JP2008175104A

JP2008175104A - Cooling device for vehicular internal combustion engine

Info

Publication number: JP2008175104A
Application number: JP2007007875A
Authority: JP
Inventors: Osamu Shintani; 治新谷
Original assignee: Toyota Motor Corp
Current assignee: Toyota Motor Corp
Priority date: 2007-01-17
Filing date: 2007-01-17
Publication date: 2008-07-31

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cooling device for a vehicular internal combustion engine capable of keeping engine cooling water temperature in a predetermined temperature range while inhibiting increase of electric power consumption of an entire cooling system. <P>SOLUTION: This cooling device is provided with cooling systems 20a, 20b circulating engine cooling water between the internal combustion engine 10 and radiators 22a, 22b by electric water pumps 21a, 21b and cooling engine cooling water in the radiators 22a, 22b by cooling air of electric fans 23a, 23b. An electronic control device 50 executes a comparison process comparing a change quantity of heat radiation quantity per unit electric power when only the drive electric power of the electric fan 23b is changed and a change quantity of heat radiation quantity per unit electric power when only the drive electric power of the electric water pump 21b is changed, and control drive electric power of the electric fans 23a, 23b and the electric water pumps 21a, 21b to keep electric power consumption of the entire cooling system small based on the result of the comparison process. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

この発明は、車両に搭載される車載内燃機関の冷却装置に関する。 The present invention relates to a cooling device for an in-vehicle internal combustion engine mounted on a vehicle.

車両に搭載される車載内燃機関の冷却装置では、機関本体に形成されたウォータジャケットに機関冷却水を循環させ、機関各部と機関冷却水との間で熱交換を行うことにより、機関各部の温度を機関運転に適した温度に維持するようにしている。また、この熱交換により温度上昇した機関冷却水は、ラジエータに供給され、空気との熱交換によって冷却された後、再び機関各部に送出される。このように車載内燃機関の冷却装置にあっては、ラジエータにより機関冷却水を冷却することにより機関冷却水の温度を所定の温度範囲に維持し、機関温度を機関運転に適した温度に維持するようにしている。 In a cooling system for an in-vehicle internal combustion engine mounted on a vehicle, engine coolant is circulated through a water jacket formed in the engine body, and heat is exchanged between the engine coolant and the engine coolant. Is maintained at a temperature suitable for engine operation. The engine cooling water whose temperature has been increased by this heat exchange is supplied to the radiator, cooled by heat exchange with air, and then sent out again to each part of the engine. As described above, in the cooling device for an on-vehicle internal combustion engine, the temperature of the engine cooling water is maintained in a predetermined temperature range by cooling the engine cooling water with the radiator, and the engine temperature is maintained at a temperature suitable for engine operation. I am doing so.

ところで、内燃機関の燃焼熱量は機関運転状態に応じて変化するため、機関冷却水温を所定の温度範囲に維持して機関温度を機関運転に適した温度とするためには、こうした燃焼熱量の変化に応じてラジエータの放熱量を変更する必要がある。しかしながら、こうした冷却装置において従来から用いられている機関駆動式のウォータポンプでは、ラジエータの放熱量を大きく左右する機関冷却水の吐出量が機関回転速度によって決定されてしまう。そのため、例えば登坂時等、機関負荷は高いものの機関回転速度が十分に上昇しないような機関運転状態においては、ラジエータの放熱量を十分に確保することができなくなるおそれがある。 By the way, since the combustion heat quantity of the internal combustion engine changes according to the engine operation state, in order to maintain the engine cooling water temperature within a predetermined temperature range and to make the engine temperature suitable for engine operation, such a change in combustion heat quantity is required. It is necessary to change the heat dissipation of the radiator according to the condition. However, in the engine-driven water pump conventionally used in such a cooling device, the discharge amount of the engine cooling water that greatly affects the heat radiation amount of the radiator is determined by the engine rotation speed. For this reason, for example, when the engine is running uphill, the engine load is high, but the engine speed is not sufficiently increased. Therefore, there is a possibility that a sufficient amount of heat radiation from the radiator cannot be secured.

そこで、特許文献１に記載の車載内燃機関の冷却装置にあっては、電動ファンの他、電動ウォータポンプを備え、これら電動ウォータポンプと電動ファンの駆動状態を機関冷却水温に基づいて変更することによってラジエータの放熱量を比較的高い自由度をもって調節するようにしている。
特開平３‐２２８１４号公報 Therefore, the on-vehicle internal combustion engine cooling device described in Patent Document 1 includes an electric water pump in addition to the electric fan, and changes the driving state of these electric water pump and electric fan based on the engine cooling water temperature. Therefore, the heat radiation amount of the radiator is adjusted with a relatively high degree of freedom.
Japanese Patent Laid-Open No. 3-22814

ここで、特許文献１に記載される装置のように、電動ファンと電動ウォータポンプとを備える車載内燃機関の冷却装置にあっては、これらを駆動するために電力が消費されるため、その電力消費量の増大を極力抑制することが重要となる。ところが、ラジエータの放熱量は、電動ファンの送風量や電動ポンプの吐出量はもとより、機関冷却水の温度、ラジエータを通過する車両走行風の量や外気温等、そのときの車両運転状態によっても種々変化する。このため、機関冷却水が所定の温度範囲に維持されるようにラジエータの放熱量を確保しつつ、電動ファンや電動ポンプの消費電力量がより少なくなるように、それらの駆動状態を制御することは極めて困難であり、従来の装置ではこの点において改善の余地を残している。 Here, as in the device described in Patent Document 1, in a cooling device for an on-vehicle internal combustion engine that includes an electric fan and an electric water pump, electric power is consumed to drive them. It is important to suppress the increase in consumption as much as possible. However, the amount of heat released from the radiator depends not only on the amount of air blown by the electric fan and the amount discharged by the electric pump, but also on the temperature of the engine cooling water, the amount of vehicle running air passing through the radiator, the outside air temperature, etc. Various changes. For this reason, controlling the driving state of the electric fan and the electric pump so that the power consumption of the electric fan and the electric pump is reduced while securing the heat radiation amount of the radiator so that the engine cooling water is maintained in a predetermined temperature range. This is extremely difficult, and there is still room for improvement in this point in the conventional apparatus.

この発明は上記実情に鑑みてなされたものであり、その目的は冷却系全体における電力消費量の増大を抑制しつつ、機関冷却水温を所定の温度域に維持することのできる車載内燃機関の冷却装置を提供することにある。 The present invention has been made in view of the above circumstances, and an object of the present invention is to cool an in-vehicle internal combustion engine capable of maintaining an engine cooling water temperature in a predetermined temperature range while suppressing an increase in power consumption in the entire cooling system. To provide an apparatus.

以下、上記目的を達成するための手段及びその作用効果について記載する。
請求項１に記載の発明は、電動ウォータポンプにより内燃機関とラジエータとの間で機関冷却水を循環させるとともに電動ファンの冷却風により前記ラジエータ内の機関冷却水を冷却する冷却系と、機関冷却水温が所定の温度域に維持されるように前記冷却系の電動ファン及び電動ウォータポンプの駆動電力を制御する制御手段とを有する車載内燃機関の冷却装置において、前記ラジエータの放熱量の変化量を機関冷却水温に基づいて推定する放熱量推定手段を備え、前記制御手段は前記電動ファンの駆動電力のみを変化させたときの単位電力当たりの放熱量の変化量と、前記電動ウォータポンプの駆動電力のみを変化させたときの単位電力当たりの放熱量の変化量とを比較する比較処理を実行し、同比較処理の結果に基づき、前記冷却系全体の電力消費量が小さくなるように前記電動ファン及び前記電動ウォータポンプの駆動電力を制御することをその要旨とする。 In the following, means for achieving the above object and its effects are described.
According to the first aspect of the present invention, there is provided a cooling system for circulating engine cooling water between an internal combustion engine and a radiator by an electric water pump, and cooling engine cooling water in the radiator by cooling air from an electric fan, and engine cooling In a cooling system for an on-vehicle internal combustion engine having a control means for controlling the driving power of the electric fan and electric water pump of the cooling system so that the water temperature is maintained in a predetermined temperature range, the amount of change in the heat radiation amount of the radiator is A heat radiation amount estimating means for estimating based on the engine coolant temperature is provided, and the control means changes the amount of heat radiation per unit power when only the driving power of the electric fan is changed, and the driving power of the electric water pump. A comparison process is performed to compare the amount of change in heat dissipation per unit power when only the change is made, and based on the result of the comparison process, the entire cooling system is As its gist to control the driving power of the electric fan and the electric water pump as the power consumption is small.

機関冷却水温が上昇している状況下でラジエータの放熱量が増大すると機関冷却水温の上昇量が減少する。また、機関冷却水温が低下している状況下でラジエータの放熱量が増大すると機関冷却水温の低下量が増大する。一方で、機関冷却水温が上昇している状況下でラジエータの放熱量が減少すると機関冷却水温の上昇量が増大し、機関冷却水温が低下している状況下でラジエータの放熱量が減少すると機関冷却水温の低下量が減少する。従って、機関冷却水温の変化量を監視することにより、ラジエータにおける放熱量の変化量を推定することができる。 When the heat dissipation amount of the radiator is increased under the condition where the engine coolant temperature is rising, the increase amount of the engine coolant temperature is decreased. Further, when the heat dissipation amount of the radiator is increased in a situation where the engine coolant temperature is decreasing, the decrease amount of the engine coolant temperature is increased. On the other hand, if the amount of heat released from the radiator decreases when the engine coolant temperature is rising, the amount of increase in the engine cooling water temperature increases, and if the amount of heat released from the radiator decreases when the engine coolant temperature is low, the engine The amount of cooling water temperature decrease is reduced. Therefore, by monitoring the amount of change in the engine coolant temperature, the amount of change in the heat dissipation amount in the radiator can be estimated.

上記請求項１に記載の構成では、電動ファンの駆動電力のみを変化させた場合と電動ウォータポンプの駆動電力のみを変化させた場合とについて、機関冷却水温に基づいて単位電力当たりの放熱量の変化量をそれぞれ推定し、それらを比較する比較処理が実行される。そして、その結果に基づいて冷却系全体の電力消費量が小さくなるように電動ファン及び電動ウォータポンプの駆動電力を変更する。そのため、機関冷却水温、車両走行風の風量、外気温等、そのときどきの車両運転状態や電動ファン及び電動ウォータポンプの各駆動状態に即した態様でラジエータの放熱量を効率的に制御することができ、冷却系全体における電力消費量の増大を抑制しつつ、機関冷却水温を所定の温度域に維持することができるようになる。 In the configuration according to claim 1, the amount of heat released per unit power based on the engine cooling water temperature when only the driving power of the electric fan is changed and when only the driving power of the electric water pump is changed. A comparison process is performed in which the amount of change is estimated and compared. Based on the result, the driving power of the electric fan and the electric water pump is changed so that the power consumption of the entire cooling system is reduced. Therefore, it is possible to efficiently control the heat radiation amount of the radiator in a manner in accordance with the vehicle driving state at that time, the driving state of the electric fan and the electric water pump, such as the engine cooling water temperature, the air flow amount of the vehicle, and the outside air temperature. Thus, the engine cooling water temperature can be maintained in a predetermined temperature range while suppressing an increase in power consumption in the entire cooling system.

請求項２に記載の発明は、請求項１に記載の車載内燃機関の冷却装置において、前記制御手段は前記ラジエータの放熱量を増大させるときに前記比較処理を実行し、前記電動ファンの駆動電力のみを変化させたときの単位電力当たりの放熱量の変化量が前記電動ウォータポンプの駆動電力のみを変化させたときの単位電力当たりの放熱量の変化量よりも大きい場合には前記電動ファンの駆動電力を増大させる一方、前記電動ファンの駆動電力のみを変化させたときの単位電力当たりの放熱量の変化量が前記電動ウォータポンプの駆動電力のみを変化させたときの単位電力当たりの放熱量の変化量よりも小さい場合には前記電動ウォータポンプの駆動電力を増大させることをその要旨とする。 According to a second aspect of the present invention, in the cooling device for an in-vehicle internal combustion engine according to the first aspect, the control means executes the comparison process when increasing the heat radiation amount of the radiator, and the driving power of the electric fan When the amount of change in the heat dissipation amount per unit power when only the change is made is larger than the amount of change in the heat dissipation amount per unit power when only the drive power of the electric water pump is changed, the electric fan The amount of heat dissipation per unit power when the amount of change in heat dissipation per unit power when only the drive power of the electric fan is changed while only the drive power of the electric water pump is changed while increasing the drive power If the amount of change is smaller than this, the gist is to increase the driving power of the electric water pump.

請求項３に記載の発明は、請求項２に記載の車載内燃機関の冷却装置において、前記制御手段は前記電動ファンの駆動電力のみを増大させたときの単位電力当たりの放熱量の増大量が前記電動ウォータポンプの駆動電力のみを増大させたときの単位電力当たりの放熱量の増大量よりも大きい場合には前記電動ファンの駆動電力を増大させる一方、前記電動ファンの駆動電力のみを増大させたときの単位電力当たりの放熱量の増大量が前記電動ウォータポンプの駆動電力のみを増大させたときの単位電力当たりの放熱量の増大量よりも小さい場合には前記電動ウォータポンプの駆動電力を増大させることをその要旨とする。 According to a third aspect of the present invention, in the cooling device for an on-vehicle internal combustion engine according to the second aspect, the amount of increase in the heat radiation amount per unit power when the control means increases only the driving power of the electric fan. When only the driving power of the electric water pump is increased, the driving power of the electric fan is increased when it is larger than the increase of the heat dissipation amount per unit power, while only the driving power of the electric fan is increased. If the increase in the amount of heat dissipation per unit power is smaller than the increase in the amount of heat dissipation per unit power when only the drive power of the electric water pump is increased, the drive power of the electric water pump is reduced. The gist is to increase it.

上記請求項２に記載の構成では、ラジエータの放熱量を増大させるときに比較処理を実行し、電動ファン及び電動ウォータポンプのうち、単位電力当たりの放熱量の変化量が大きい方の駆動電力を増大させるようにしている。そのため、より少ない消費電力の増大をもってラジエータの放熱量を効率的に増大させることができる。その結果、冷却系全体における電力消費量の増大を抑制しつつ、機関冷却水温を所定の温度域に維持することができるようになる。 In the configuration of the second aspect, the comparison process is executed when the heat dissipation amount of the radiator is increased, and the driving power having the larger change amount of the heat dissipation amount per unit power is selected from the electric fan and the electric water pump. Try to increase. Therefore, the heat dissipation amount of the radiator can be increased efficiently with a smaller increase in power consumption. As a result, the engine cooling water temperature can be maintained in a predetermined temperature range while suppressing an increase in power consumption in the entire cooling system.

具体的には請求項３に記載の発明によるように、電動ファンの駆動電力のみを増大させたときの単位電力当たりの放熱量の増大量と、電動ウォータポンプの駆動電力のみを増大させたときの単位電力当たりの放熱量の増大量とを比較する比較処理を実行し、それら電動ファン及び電動ウォータポンプのうち単位電力当たりの放熱量の増大量が大きい方の駆動電力を増大させるといった構成を採用することができる。こうした構成によれば、ラジエータの放熱量を増大させるときの電動ファン及び電動ウォータポンプの各駆動状態の変化に即した態様で比較処理を実行することができるようになり、ラジエータの放熱量をより効率的に増大させることができるようになる。 Specifically, when only the driving power of the electric fan is increased and only the driving power of the electric water pump is increased when only the driving power of the electric fan is increased. A comparison process is performed to compare the amount of increase in the heat dissipation amount per unit power, and the drive power with the larger amount of increase in the heat dissipation amount per unit power among the electric fan and the electric water pump is increased. Can be adopted. According to such a configuration, it becomes possible to perform the comparison process in a manner in accordance with changes in the driving states of the electric fan and the electric water pump when increasing the heat dissipation amount of the radiator, and the heat dissipation amount of the radiator is further increased. It can be increased efficiently.

尚ここで、「電動ファンの駆動電力を増大させる」場合には、電動ファンの駆動電力のみを増大させる場合はもとより、電動ファン及び電動ウォータポンプの駆動電力の双方を増大させる際に、その電動ファンに関する増大量を電動ウォータポンプに関する増大量よりも大きく設定する場合も含まれる。また同様に、「電動ウォータポンプの駆動電力を増大させる」場合には、電動ウォータポンプの駆動電力のみを増大させる場合の他、電動ファン及び電動ウォータポンプの駆動電力の双方を増大させる際に、その電動ウォータポンプに関する増大量を電動ファンに関する増大量よりも大きく設定する場合も含まれる。 Here, in the case of “increasing the driving power of the electric fan”, not only the driving power of the electric fan is increased, but also when the driving power of both the electric fan and the electric water pump is increased. The case where the increase amount related to the fan is set larger than the increase amount related to the electric water pump is also included. Similarly, in the case of “increasing the driving power of the electric water pump”, in addition to increasing only the driving power of the electric water pump, when increasing both the driving power of the electric fan and the electric water pump, The case where the increase amount related to the electric water pump is set larger than the increase amount related to the electric fan is also included.

請求項４に記載の発明は、請求項１に記載の車載内燃機関の冷却装置において、前記制御手段は前記ラジエータの放熱量を減少させるときに前記比較処理を実行し、前記電動ファンの駆動電力のみを変化させたときの単位電力当たりの放熱量の変化量が前記電動ウォータポンプの駆動電力のみを変化させたときの単位電力当たりの放熱量の変化量よりも小さい場合には前記電動ファンの駆動電力を減少させる一方、前記電動ファンの駆動電力のみを変化させたときの単位電力当たりの放熱量の変化量が前記電動ウォータポンプの駆動電力のみを変化させたときの単位電力当たりの放熱量の変化量よりも大きい場合には前記電動ウォータポンプの駆動電力を減少させることをその要旨とする。 According to a fourth aspect of the present invention, in the cooling apparatus for an on-vehicle internal combustion engine according to the first aspect, the control means executes the comparison process when reducing the heat radiation amount of the radiator, and the driving power of the electric fan When the amount of change in the heat dissipation amount per unit power when only the change is made is smaller than the amount of change in the heat dissipation amount per unit power when only the drive power of the electric water pump is changed, the electric fan The amount of heat dissipation per unit power when only the drive power of the electric water pump is changed while the amount of change in the heat dissipation amount per unit power when only the drive power of the electric fan is changed while reducing the drive power If the amount of change is larger than this, the gist is to reduce the drive power of the electric water pump.

請求項５に記載の発明は、請求項４に記載の車載内燃機関の冷却装置において、前記制御手段は前記電動ファンの駆動電力のみを減少させたときの単位電力当たりの放熱量の減少量が前記電動ウォータポンプの駆動電力のみを減少させたときの単位電力当たりの放熱量の減少量よりも小さい場合には前記電動ファンの駆動電力を減少させる一方、前記電動ファンの駆動電力のみを減少させたときの単位電力当たりの放熱量の減少量が前記電動ウォータポンプの駆動電力のみを減少させたときの単位電力当たりの放熱量の減少量よりも大きい場合には前記電動ウォータポンプの駆動電力を減少させることをその要旨とする。 According to a fifth aspect of the present invention, in the on-vehicle internal combustion engine cooling device according to the fourth aspect of the present invention, when the control means reduces only the driving power of the electric fan, the amount of decrease in the heat radiation amount per unit power is reduced. When the amount of heat radiation per unit power is less than the reduction amount of the electric water pump when only the driving power of the electric water pump is reduced, the driving power of the electric fan is reduced while only the driving power of the electric fan is reduced. If the reduction amount of the heat dissipation per unit power at the time is larger than the reduction amount of the heat dissipation per unit power when only the driving power of the electric water pump is reduced, the driving power of the electric water pump is reduced. The gist is to reduce it.

上記請求項４に記載の構成では、ラジエータの放熱量を減少させるときに比較処理を実行し、電動ファン及び電動ウォータポンプのうち、単位電力当たりの放熱量の変化量が小さい方の駆動電力を減少させるようにしている。そのため、ラジエータの放熱量を所定量だけ減少させるのに際し、冷却系全体における駆動電力をより大きく減少させることができる。その結果、冷却系全体における電力消費量の増大を抑制しつつ、機関冷却水温を所定の温度域に維持することができるようになる。 In the configuration according to claim 4, the comparison process is performed when the heat dissipation amount of the radiator is decreased, and the driving power having the smaller change amount of the heat dissipation amount per unit power is selected from the electric fan and the electric water pump. I try to decrease. Therefore, when reducing the amount of heat released from the radiator by a predetermined amount, the driving power in the entire cooling system can be greatly reduced. As a result, the engine cooling water temperature can be maintained in a predetermined temperature range while suppressing an increase in power consumption in the entire cooling system.

具体的には請求項５に記載の発明によるように、ラジエータの放熱量を減少させるときに電動ファンの駆動電力のみを減少させたときの単位電力当たりの放熱量の減少量と、電動ウォータポンプの駆動電力のみを減少させたときの単位電力当たりの放熱量の減少量とを比較する比較処理を実行し、それら電動ファン及び電動ウォータポンプのうち単位電力当たりの放熱量の減少量が小さい方の駆動電力を減少させるといった構成を採用することができる。こうした構成によれば、ラジエータの放熱量を減少させるときの電動ファン及び電動ウォータポンプの各駆動状態の変化に即した態様で比較処理を実行することができるようになり、ラジエータの放熱量をより効率的に減少させることができるようになる。 Specifically, according to the invention described in claim 5, when the amount of heat radiation of the radiator is decreased, the amount of decrease in the amount of heat radiation per unit power when only the driving power of the electric fan is decreased, and the electric water pump One of the electric fan and electric water pump that has the smaller amount of decrease in heat dissipation per unit power is compared with the amount of decrease in heat dissipation per unit power when only the drive power of the motor is reduced. It is possible to adopt a configuration in which the driving power of the motor is reduced. According to such a configuration, the comparison process can be executed in a manner in accordance with changes in the driving states of the electric fan and the electric water pump when the heat dissipation amount of the radiator is reduced, and the radiator heat dissipation amount is further increased. It can be reduced efficiently.

尚ここで、「電動ファンの駆動電力を減少させる」場合には、電動ファンの駆動電力のみを減少させる場合はもとより、電動ファン及び電動ウォータポンプの駆動電力の双方を減少させる際に、その電動ファンに関する減少量を電動ウォータポンプに関する減少量よりも大きく設定する場合も含まれる。また同様に、「電動ウォータポンプの駆動電力を減少させる」場合には、電動ウォータポンプの駆動電力のみを減少させる場合の他、電動ファン及び電動ウォータポンプの駆動電力の双方を減少させる際に、その電動ウォータポンプに関する減少量を電動ファンに関する減少量よりも大きく設定する場合も含まれる。 Here, in the case of “decreasing the drive power of the electric fan”, not only the drive power of the electric fan is reduced, but also when the drive power of both the electric fan and the electric water pump is reduced. The case where the amount of reduction related to the fan is set larger than the amount of reduction related to the electric water pump is also included. Similarly, in the case of “decreasing the driving power of the electric water pump”, when reducing both the driving power of the electric fan and the electric water pump, in addition to reducing only the driving power of the electric water pump, The case where the amount of reduction related to the electric water pump is set larger than the amount of reduction related to the electric fan is also included.

請求項６に記載の発明は、請求項１〜５のいずれか一項に記載の車載内燃機関の冷却装置において、放熱量推定手段は前記ラジエータから送出されて前記内燃機関に流入する前の機関冷却水の温度を検出する水温検出手段を備え、同水温検出手段によって検出された機関冷却水温に基づいて前記ラジエータの放熱量の変化量を推定することをその要旨とする。 According to a sixth aspect of the present invention, in the on-vehicle internal combustion engine cooling apparatus according to any one of the first to fifth aspects, the heat radiation amount estimating means is an engine before being sent from the radiator and flowing into the internal combustion engine. The gist of the invention is to provide a water temperature detecting means for detecting the temperature of the cooling water, and to estimate the amount of change in the heat radiation amount of the radiator based on the engine cooling water temperature detected by the water temperature detecting means.

ラジエータから送出されて内燃機関に流入する前の機関冷却水温を検出し、その機関冷却水温に基づいてラジエータの放熱量の変化量を推定するようにした上記構成によれば、同水温検出手段により検出される機関冷却水温が機関燃焼熱の影響により変化することを抑制することができ、ラジエータにおける放熱量の変化量をより正確に推定することができるようになる。 According to the above configuration in which the engine coolant temperature before being sent from the radiator and flowing into the internal combustion engine is detected, and the amount of change in the heat radiation amount of the radiator is estimated based on the engine coolant temperature, the water temperature detecting means It is possible to suppress the detected engine coolant temperature from changing due to the influence of engine combustion heat, and it is possible to more accurately estimate the amount of change in the heat radiation amount in the radiator.

請求項７に記載の発明は、電動ウォータポンプにより内燃機関とラジエータとの間で機関冷却水を循環させるとともに電動ファンの冷却風によりラジエータ内の機関冷却水を冷却する一対の冷却系が機関冷却水の循環経路に並列に配設され、機関冷却水温が所定の温度域に維持されるように前記一対の冷却系の各電動ファン及び各電動ウォータポンプの駆動電力を制御する制御手段を有する車載内燃機関の冷却装置において、前記一対の冷却系の各ラジエータから送出されて他方のラジエータから放出された機関冷却水温と合流する前の機関冷却水温をそれぞれ検出する一対の水温検出手段を有し、同水温検出手段によって検出される機関冷却水温に基づいて各ラジエータの放熱量を各別に推定する放熱量推定手段を備え、前記制御手段は前記一対の冷却系のうち一方の冷却系における電動ファンの駆動電力のみを変化させたときの単位電力当たりの放熱量の変化量と、他方の冷却系における電動ウォータポンプの駆動電力のみを変化させたときの単位電力当たりの放熱量の変化量とを比較する比較処理を実行し、同比較処理の結果に基づき、前記冷却系全体の電力消費量が小さくなるように前記一対の冷却系の各電動ファン及び各電動ウォータポンプの駆動電力を制御することをその要旨とする。 According to the seventh aspect of the present invention, a pair of cooling systems for circulating the engine cooling water between the internal combustion engine and the radiator by the electric water pump and cooling the engine cooling water in the radiator by the cooling air of the electric fan are engine cooling. An in-vehicle unit that is arranged in parallel with the water circulation path and has control means for controlling the driving power of each electric fan and each electric water pump of the pair of cooling systems so that the engine cooling water temperature is maintained in a predetermined temperature range. In the cooling apparatus for an internal combustion engine, the engine includes a pair of water temperature detecting means for detecting the engine cooling water temperature before being merged with the engine cooling water temperature sent from each radiator of the pair of cooling systems and discharged from the other radiator, The control means comprises a heat radiation amount estimating means for estimating the heat radiation amount of each radiator separately based on the engine cooling water temperature detected by the water temperature detecting means. Of the pair of cooling systems, only the drive power of the electric fan in one cooling system was changed, and the amount of change in heat dissipation per unit power and only the drive power of the electric water pump in the other cooling system were changed. A comparison process for comparing the amount of change in the heat dissipation amount per unit power is performed, and based on the result of the comparison process, the electric motors of the pair of cooling systems are reduced so that the power consumption of the entire cooling system is reduced. The gist is to control the driving power of the fan and each electric water pump.

上記構成では、機関冷却水の循環経路に並列に配設された一対の冷却系に各ラジエータから送出されて他方のラジエータから放出された機関冷却水と合流する前の機関冷却水温を検出する水温検出手段がそれぞれ設けられている。そのため、他方のラジエータの放熱量が変化することによる影響によって各水温検出手段により検出される機関冷却水温が変化することを抑制することができ、各ラジエータにおける放熱量の変化量をより正確に推定することができるようになる。そして、一対の冷却系のうち一方の冷却系の電動ファンの駆動電力のみを変化させたときの単位電力当たりの放熱量の変化量と、他方の冷却系の電動ウォータポンプの駆動電力のみを変化させたときの単位電力当たりの放熱量の変化量とを比較する比較処理を実行し、その結果に基づいて冷却系全体の電力消費量が小さくなるように一対の冷却系の各電動ファン及び各電動ウォータポンプの駆動電力を変化させるようにしている。従って、上記請求項７に記載の発明によれば、機関冷却水温、車両走行風の風量、外気温等、そのときどきの車両運転状態や電動ファン及び電動ウォータポンプの各駆動状態により即した態様でラジエータの放熱量を効率的に制御することができ、冷却系全体における電力消費量の増大を抑制しつつ、機関冷却水温を所定の温度域に維持することができるようになる。 In the above configuration, the water temperature for detecting the engine cooling water temperature before joining the engine cooling water sent from each radiator to the pair of cooling systems arranged in parallel with the circulation path of the engine cooling water and discharged from the other radiator. Each detecting means is provided. Therefore, it is possible to suppress changes in the engine cooling water temperature detected by each water temperature detection means due to the influence of the change in the heat dissipation amount of the other radiator, and more accurately estimate the amount of change in the heat dissipation amount in each radiator. Will be able to. And, only the drive power of the electric water pump of the other cooling system and the change amount of the heat dissipation per unit power when only the drive power of the electric fan of one cooling system is changed among the pair of cooling systems are changed. A comparison process is performed to compare the amount of change in the amount of heat dissipation per unit power at the time of the operation, and based on the result, the electric fans of the pair of cooling systems and each of the cooling systems so that the power consumption of the entire cooling system is reduced The driving power of the electric water pump is changed. Therefore, according to the seventh aspect of the present invention, the engine cooling water temperature, the volume of the vehicle traveling wind, the outside air temperature, etc., such as the vehicle operating state at that time and the driving states of the electric fan and the electric water pump can be used. The amount of heat released from the radiator can be efficiently controlled, and the engine cooling water temperature can be maintained in a predetermined temperature range while suppressing an increase in power consumption in the entire cooling system.

請求項８に記載の発明は、請求項７に記載の車載内燃機関の冷却装置において、前記制御手段は前記比較処理に際して前記一対の冷却系のうち一方の冷却系における電動ファンの駆動電力と、他方の冷却系における電動ウォータポンプの駆動電力とを同時に変化させることをその要旨とする。 According to an eighth aspect of the present invention, in the cooling device for an in-vehicle internal combustion engine according to the seventh aspect, the control means includes a driving power of an electric fan in one cooling system of the pair of cooling systems during the comparison process, The gist is to simultaneously change the driving power of the electric water pump in the other cooling system.

比較処理に際し、電動ファンの駆動電力のみを変化させたときの単位電力当たりの放熱量の変化量を推定する時期と、電動ウォータポンプの駆動電力のみを変化させたときの単位電力当たりの放熱量の変化量を推定する時期とが大きく異なっていると、それら推定時期の間に車両走行風の風量や外気温等、車両運転状態が変動した場合にその影響が無視できないものとなり、比較処理における比較結果の信頼性が低下することとなる。 During the comparison process, the time to estimate the amount of change in heat dissipation per unit power when only the drive power of the electric fan is changed, and the amount of heat dissipation per unit power when only the drive power of the electric water pump is changed If the amount of change in the vehicle is significantly different from the estimated time, the effects of changes in vehicle operating conditions, such as the volume of the vehicle running wind and the outside air temperature during these estimated times, cannot be ignored. The reliability of the comparison result will be reduced.

この点、上記請求項８に記載の構成によれば、比較処理に際して電動ファンの駆動電力と電動ウォータポンプの駆動電力とを同時に変化させるようにしているため、車両運転状態が変動しているような状況にあっても、電動ファン、電動ウォータポンプの駆動電力を変化させたときの単位電力当たりの放熱量の各変化量を同じ車両運転状態のもとで推定することができ、比較処理における比較結果の信頼性低下を回避することができるようになる。 In this regard, according to the configuration described in claim 8, since the driving power of the electric fan and the driving power of the electric water pump are changed at the same time in the comparison process, the vehicle operating state seems to fluctuate. Even if there is a situation, it is possible to estimate the amount of change in the heat dissipation per unit power when the driving power of the electric fan and electric water pump is changed under the same vehicle operating condition, A reduction in the reliability of the comparison result can be avoided.

請求項９に記載の発明は、請求項７又は請求項８に記載の車載内燃機関の冷却装置において、前記制御手段は各ラジエータの放熱量を増大させて前記冷却系全体の冷却能力を増大させるときに前記比較処理を実行し、前記一方の冷却系における電動ファンの駆動電力のみを変化させたときの単位電力当たりの放熱量の変化量が前記他方の冷却系における電動ウォータポンプの駆動電力のみを変化させたときの単位電力当たりの放熱量の変化量よりも大きい場合には前記一対の冷却系における各電動ファンの駆動電力をそれぞれ増大させる一方、前記一方の冷却系における電動ファンの駆動電力のみを変化させたときの単位電力当たりの放熱量の変化量が前記他方の冷却系における電動ウォータポンプの駆動電力のみを変化させたときの単位電力当たりの放熱量の変化量よりも小さい場合には前記一対の冷却系における各電動ウォータポンプの駆動電力をそれぞれ増大させることをその要旨とする。 According to a ninth aspect of the present invention, in the on-vehicle internal combustion engine cooling device according to the seventh or eighth aspect, the control means increases the heat radiation amount of each radiator to increase the cooling capacity of the entire cooling system. Sometimes when the comparison process is executed and only the driving power of the electric fan in the one cooling system is changed, the amount of change in the heat dissipation amount per unit power is only the driving power of the electric water pump in the other cooling system. Is larger than the amount of change in the amount of heat dissipation per unit power when the power is changed, the driving power of each electric fan in the pair of cooling systems is increased while the driving power of the electric fan in the one cooling system The amount of change in the amount of heat released per unit power when only the change is made changes only the drive power of the electric water pump in the other cooling system. It is smaller than the amount of change in the heat radiation amount per are and its gist at increasing respectively the driving power of the electric water pump in the pair of the cooling system.

請求項１０に記載の発明は、請求項９に記載の車載内燃機関の冷却装置において、前記制御手段は前記一方の冷却系における電動ファンの駆動電力のみを増大させたときの単位電力当たりの放熱量の増大量が前記他方の冷却系における電動ウォータポンプの駆動電力のみを増大させたときの単位電力当たりの放熱量の増大量よりも大きい場合には前記一対の冷却系の電動ファンの駆動電力を増大させる一方、前記一方の冷却系における電動ファンの駆動電力のみを増大させたときの単位電力当たりの放熱量の増大量が前記他方の冷却系における電動ウォータポンプの駆動電力のみを増大させたときの単位電力当たりの放熱量の増大量よりも小さい場合には前記一対の冷却系の電動ウォータポンプの駆動電力を増大させることをその要旨とする。 According to a tenth aspect of the present invention, in the cooling device for an on-vehicle internal combustion engine according to the ninth aspect, the control means releases the discharge per unit power when only the driving power of the electric fan in the one cooling system is increased. When the amount of increase in heat is larger than the amount of increase in heat dissipation per unit power when only the driving power of the electric water pump in the other cooling system is increased, the driving power of the pair of cooling system electric fans On the other hand, when only the driving power of the electric fan in the one cooling system is increased, only the driving power of the electric water pump in the other cooling system is increased due to the increase in the heat dissipation amount per unit power. The main point is to increase the driving power of the electric water pump of the pair of cooling systems when the amount of heat radiation per unit power is smaller than the increase amount.

上記請求項９に記載の構成では、一対の冷却系全体の冷却能力を増大させるときに比較処理を実行し、電動ファン及び電動ウォータポンプのうち、単位電力当たりの放熱量の変化量が大きい方の駆動電力を増大させるようにしている。そのため、より少ない消費電力の増大をもって冷却系全体の冷却能力を効率的に増大させることができる。その結果、冷却系全体における電力消費量の増大を抑制しつつ、機関冷却水温を所定の温度域に維持することができるようになる。 In the configuration according to the ninth aspect, the comparison process is executed when the cooling capacity of the entire pair of cooling systems is increased, and one of the electric fan and the electric water pump having the larger amount of change in the heat radiation amount per unit electric power. The driving power is increased. Therefore, the cooling capacity of the entire cooling system can be efficiently increased with a smaller increase in power consumption. As a result, the engine cooling water temperature can be maintained in a predetermined temperature range while suppressing an increase in power consumption in the entire cooling system.

具体的には請求項１０に記載の発明によるように、一方の冷却系における電動ファンの駆動電力のみを増大させたときの単位電力当たりの放熱量の増大量と、他方の冷却系における電動ウォータポンプの駆動電力のみを増大させたときの単位電力当たりの放熱量の増大量とを比較する比較処理を実行し、それら電動ファン及び電動ウォータポンプのうち単位電力当たりの放熱量の増大量が大きい方の駆動電力を増大させるといった構成を採用することができる。こうした構成によれば、冷却系全体の冷却能力を増大させるときの電動ファン及び電動ウォータポンプの各駆動状態の変化に即した態様で比較処理を実行することができるようになり、冷却系全体の冷却能力をより効率的に増大させることができるようになる。 Specifically, according to the invention described in claim 10, when only the driving power of the electric fan in one cooling system is increased, the amount of heat dissipation per unit power is increased, and the electric water in the other cooling system. A comparison process is performed to compare the amount of increase in heat dissipation per unit power when only the drive power of the pump is increased, and the amount of increase in heat dissipation per unit power is large among those electric fans and electric water pumps. It is possible to adopt a configuration in which the driving power of the other side is increased. According to such a configuration, the comparison process can be executed in a manner in accordance with changes in the driving states of the electric fan and the electric water pump when the cooling capacity of the entire cooling system is increased. The cooling capacity can be increased more efficiently.

請求項１１に記載の発明は、請求項７又は請求項８に記載の車載内燃機関の冷却装置において、前記制御手段は各ラジエータの放熱量を減少させて前記冷却系全体の冷却能力を低下させるときに前記比較処理を実行し、前記一方の冷却系における電動ファンの駆動電力のみを変化させたときの単位電力当たりの放熱量の変化量が前記他方の冷却系における電動ウォータポンプの駆動電力のみを変化させたときの単位電力当たりの放熱量の変化量よりも小さい場合には前記一対の冷却系の電動ファンの駆動電力を減少させる一方、前記一方の冷却系における電動ファンの駆動電力のみを変化させたときの単位電力当たりの放熱量の変化量が前記他方の冷却系における電動ウォータポンプの駆動電力のみを変化させたときの単位電力当たりの放熱量の変化量よりも大きい場合には前記一対の冷却系の電動ウォータポンプの駆動電力を減少させることをその要旨とする。 According to an eleventh aspect of the present invention, in the cooling device for an on-vehicle internal combustion engine according to the seventh or eighth aspect, the control means decreases a cooling capacity of the entire cooling system by decreasing a heat radiation amount of each radiator. Sometimes when the comparison process is executed and only the driving power of the electric fan in the one cooling system is changed, the amount of change in the heat dissipation amount per unit power is only the driving power of the electric water pump in the other cooling system. Is smaller than the amount of change in heat dissipation per unit power when changing the power, the drive power of the electric fan of the pair of cooling systems is reduced, while only the drive power of the electric fan in the one cooling system is reduced. Heat dissipation per unit power when the amount of change in heat dissipation per unit power when changing only the drive power of the electric water pump in the other cooling system When than the amount of change is greater, and its gist to reduce the driving power of the electric water pump of the pair of cooling system.

請求項１２に記載の発明は、請求項１１に記載の車載内燃機関の冷却装置において、前記制御手段は前記一方の冷却系の電動ファンの駆動電力のみを減少させたときの単位電力当たりの放熱量の減少量が前記他方の冷却系の電動ウォータポンプの駆動電力のみを減少させたときの単位電力当たりの放熱量の減少量よりも小さい場合には前記一対の冷却系の電動ファンの駆動電力を減少させる一方、前記一方の冷却系の電動ファンの駆動電力のみを減少させたときの単位電力当たりの放熱量の減少量が前記他方の冷却系の電動ウォータポンプの駆動電力のみを減少させたときの単位電力当たりの放熱量の減少量よりも大きい場合には前記一対の冷却系の電動ウォータポンプの駆動電力を減少させることをその要旨とする。 According to a twelfth aspect of the present invention, there is provided a cooling system for an on-vehicle internal combustion engine according to the eleventh aspect, wherein the control means releases the power per unit power when only the driving power of the electric fan of the one cooling system is reduced. When the amount of decrease in heat is smaller than the amount of decrease in heat dissipation per unit power when only the drive power of the electric water pump of the other cooling system is decreased, the drive power of the pair of cooling system electric fans On the other hand, when only the driving power of the electric fan of the one cooling system is reduced, the amount of decrease in the heat radiation per unit power reduces only the driving power of the electric water pump of the other cooling system. The main point is to reduce the driving power of the electric water pump of the pair of cooling systems when the heat dissipation amount per unit power is larger than the decrease amount.

上記請求項１１に記載の構成では、一対の冷却系全体の冷却能力を低下させるときに比較処理を実行し、電動ファン及び電動ウォータポンプのうち、単位電力当たりの放熱量の変化量が小さい方の駆動電力を減少させるようにしている。そのため、一対の冷却系全体の冷却能力を所定量だけ減少させるのに際し、冷却系全体における駆動電力をより大きく減少させることができる。その結果、冷却系全体における電力消費量の増大を抑制しつつ、機関冷却水温を所定の温度域に維持することができるようになる。 In the configuration according to claim 11, the comparison process is executed when the cooling capacity of the entire pair of cooling systems is reduced, and the change in the amount of heat radiation per unit power is smaller between the electric fan and the electric water pump. The drive power is reduced. Therefore, when reducing the cooling capacity of the entire pair of cooling systems by a predetermined amount, the driving power in the entire cooling system can be greatly reduced. As a result, the engine cooling water temperature can be maintained in a predetermined temperature range while suppressing an increase in power consumption in the entire cooling system.

具体的には請求項１２に記載の発明によるように、一対の冷却系の放熱量を減少させるときに一方の冷却系の電動ファンの駆動電力のみを減少させたときの単位電力当たりの放熱量の減少量と、他方の電動ウォータポンプの駆動電力のみを減少させたときの単位電力当たりの放熱量の減少量とを比較する比較処理を実行し、それら電動ファン及び電動ウォータポンプのうち単位電力当たりの放熱量の減少量が小さい方の駆動電力を減少させるといった構成を採用することができる。こうした構成によれば、一対の冷却系全体の冷却能力を低下させるときの電動ファン及び電動ウォータポンプの各駆動状態の変化に即した態様で比較処理を実行することができるようになり、一対の冷却系全体の冷却能力をより効率的に減少させることができるようになる。 Specifically, as in the invention described in claim 12, when the heat radiation amount of the pair of cooling systems is decreased, the heat radiation amount per unit power when only the driving power of the electric fan of one cooling system is decreased. Is compared with the reduction amount of heat dissipation per unit power when only the driving power of the other electric water pump is reduced, and the unit power of the electric fan and electric water pump is compared. It is possible to employ a configuration in which the drive power with the smaller amount of reduction in the amount of heat released per unit is reduced. According to such a configuration, the comparison process can be executed in a manner in accordance with changes in the driving states of the electric fan and the electric water pump when the cooling capacity of the entire pair of cooling systems is reduced. The cooling capacity of the entire cooling system can be reduced more efficiently.

以下、この発明にかかる車載内燃機関の冷却装置を具体化した一実施形態について、図１〜図７を参照して説明する。
図１は、本実施形態にかかる冷却装置の概略構成を示している。図１に示されるように、内燃機関１０には、そのシリンダを取り囲むように機関冷却水が循環するウォータジャケット１２が形成されている。また、ウォータジャケット１２には、機関冷却水温ＴＨＷを検出する機関水温センサ５１が設けられている。 Hereinafter, an embodiment of a cooling device for an onboard internal combustion engine according to the present invention will be described with reference to FIGS.
FIG. 1 shows a schematic configuration of a cooling device according to the present embodiment. As shown in FIG. 1, the internal combustion engine 10 is formed with a water jacket 12 through which engine cooling water circulates so as to surround the cylinder. The water jacket 12 is provided with an engine water temperature sensor 51 for detecting the engine cooling water temperature THW.

また、機関冷却水の循環経路には、図１に示されるようにそれぞれ同じ諸元を有する電動ウォータポンプ２１、ラジエータ２２、電動ファン２３とこれらを接続する冷却水通路を備えた第１冷却系２０ａと第２冷却系２０ｂとが並列に接続されている。 Further, in the circulation path of the engine cooling water, as shown in FIG. 1, a first cooling system provided with an electric water pump 21, a radiator 22 and an electric fan 23 each having the same specifications and a cooling water passage connecting them. 20a and the second cooling system 20b are connected in parallel.

以下、第１冷却系２０ａについてその構成を詳しく説明する。尚、第２冷却系２０ｂは、第１冷却系２０ａと構成が同一であるため、その説明を割愛する。以下の説明では、各冷却系２０ａ，２０ｂにおいて同じ機能を有する部材については同じ符号を付すとともに、第１冷却系２０ａを構成する各部材についてはその符号に添え字「ａ」を付し、第２冷却系２０ｂを構成する部材についてはその符号に「ｂ」を付すことによってそれらを区別する。また、各部材について特に添え字を付さない場合には、これら第１冷却系２０ａ及び第２冷却系２０ｂの双方の部材を示すこととする。 Hereinafter, the configuration of the first cooling system 20a will be described in detail. Note that the second cooling system 20b has the same configuration as the first cooling system 20a, and thus the description thereof is omitted. In the following description, the members having the same functions in the respective cooling systems 20a and 20b are denoted by the same reference numerals, and the members constituting the first cooling system 20a are denoted by the suffix “a”. The members constituting the two cooling systems 20b are distinguished from each other by attaching “b” to the reference numerals. In addition, in the case where no subscript is attached to each member, both the members of the first cooling system 20a and the second cooling system 20b are shown.

第１冷却系２０ａにおける電動ウォータポンプ２１ａは、吐出通路２４ａによって内燃機関１０のウォータジャケット１２に接続されている。電動ウォータポンプ２１ａによって吐出された機関冷却水は、吐出通路２４ａを通じてウォータジャケット１２に導入され、同ウォータジャケット１２を循環することによりシリンダ及び機関各部を冷却する。そして、シリンダ及び機関各部の熱を奪って温められた機関冷却水は、排出通路２５ａを通じて第１冷却系２０ａへと供給される。この排出通路２５ａはその下流側においてラジエータ２２ａに接続される導入通路２６ａと、サーモスタットバルブ３０に接続されるバイパス通路２７ａとに分岐しており、排出通路２５ａの機関冷却水は導入通路２６ａを通じてラジエータ２２ａに導入される。ラジエータ２２ａには、その車両後方側に位置し、電動モータの駆動力によってラジエータ２２ａに冷却風を送風する電動ファン２３ａが取り付けられている。尚、電動ウォータポンプ２１ａの吐出量はその駆動電力が大きくなるほど多くなり、電動ファン２３ａについても同様に、駆動電力が大きくなるほど送風量が多くなる。 The electric water pump 21a in the first cooling system 20a is connected to the water jacket 12 of the internal combustion engine 10 by a discharge passage 24a. The engine cooling water discharged by the electric water pump 21a is introduced into the water jacket 12 through the discharge passage 24a and circulates in the water jacket 12 to cool the cylinder and each part of the engine. The engine cooling water heated by removing heat from the cylinders and the engine parts is supplied to the first cooling system 20a through the discharge passage 25a. The discharge passage 25a is branched downstream into an introduction passage 26a connected to the radiator 22a and a bypass passage 27a connected to the thermostat valve 30, and the engine coolant in the discharge passage 25a passes through the introduction passage 26a. 22a. The radiator 22a is provided with an electric fan 23a that is located on the rear side of the vehicle and blows cooling air to the radiator 22a by the driving force of the electric motor. The discharge amount of the electric water pump 21a increases as the driving power increases, and the electric fan 23a similarly increases the blowing amount as the driving power increases.

また、ラジエータ２２ａの下流側には、還流通路２８ａが接続されている。この還流通路２８ａは、サーモスタットバルブ３０ａ及び吸入通路２９ａを介して電動ウォータポンプ２１ａに接続されている。即ち、ラジエータ２２ａによって冷却された機関冷却水は、還流通路２８ａ、サーモスタットバルブ３０ａ、吸入通路２９ａを介して電動ウォータポンプ２１ａに吸入され、再び、内燃機関１０のウォータジャケット１２に吐出される。また、図１に示されるようにこの還流通路２８ａには、ラジエータ２２ａから送出された機関冷却水の水温ＴＨＷ１を検出する水温センサ５２ａが設けられている。 A reflux passage 28a is connected to the downstream side of the radiator 22a. The recirculation passage 28a is connected to the electric water pump 21a via a thermostat valve 30a and a suction passage 29a. That is, the engine coolant cooled by the radiator 22a is sucked into the electric water pump 21a through the recirculation passage 28a, the thermostat valve 30a, and the suction passage 29a, and is discharged again to the water jacket 12 of the internal combustion engine 10. Further, as shown in FIG. 1, a water temperature sensor 52a for detecting the temperature THW1 of the engine cooling water sent from the radiator 22a is provided in the recirculation passage 28a.

また、バイパス通路２７ａ、還流通路２８ａ及び吸入通路２９ａがそれぞれ接続されるサーモスタットバルブ３０ａは、機関冷却水の温度に応じてその循環態様を切り替える。具体的には、機関冷間始動時のように機関冷却水の温度が低い場合には、バイパス通路２７ａと吸入通路２９ａとを連通させるとともに、還流通路２８ａを閉鎖する。従って、ウォータジャケット１２から排出された機関冷却水はラジエータ２２ａをバイパスして再びウォータジャケット１２に戻される。こうして機関冷間時には、ラジエータ２２ａによる機関冷却水の冷却を行わずに機関冷却水の温度を速やかに上昇させる。一方で、機関冷却水の温度が高くなった場合には、バイパス通路２７ａを閉鎖するとともに、還流通路２８ａと吸入通路２９ａとを連通させ、ラジエータ２２ａを介して機関冷却水を循環させる。 Further, the thermostat valve 30a to which the bypass passage 27a, the reflux passage 28a, and the suction passage 29a are respectively connected switches the circulation mode according to the temperature of the engine cooling water. Specifically, when the temperature of the engine coolant is low, such as at the time of engine cold start, the bypass passage 27a and the suction passage 29a are communicated with each other and the recirculation passage 28a is closed. Accordingly, the engine coolant discharged from the water jacket 12 bypasses the radiator 22a and is returned to the water jacket 12 again. Thus, when the engine is cold, the temperature of the engine cooling water is quickly raised without cooling the engine cooling water by the radiator 22a. On the other hand, when the temperature of the engine cooling water becomes high, the bypass passage 27a is closed, the reflux passage 28a and the suction passage 29a are connected, and the engine cooling water is circulated through the radiator 22a.

上述したように第２冷却系２０ｂは、第１冷却系２０ａと同様の構成を有している。そして、こうした一対の冷却系２０ａ，２０ｂを備える本実施形態の冷却装置では、内燃機関１０のウォータジャケット１２から排出された機関冷却水をこれら冷却系２０ａ，２０ｂを通じて冷却することにより、内燃機関１０の温度を機関運転に適した温度に維持するようにしている。即ち、内燃機関１０の温度が過度に上昇すると、ピストンの焼き付き等が発生する一方、その温度が過度に低下すると燃焼状態の悪化や駆動抵抗の増大、ひいてはそれらに起因する燃費の低下を招くこととなる。このため、本冷却装置は機関冷却水の温度を所定の温度範囲に維持することにより、こうした機関温度の過度な上昇や低下を抑制するようにしている。 As described above, the second cooling system 20b has the same configuration as the first cooling system 20a. And in the cooling device of this embodiment provided with such a pair of cooling systems 20a, 20b, the engine cooling water discharged from the water jacket 12 of the internal combustion engine 10 is cooled through these cooling systems 20a, 20b, whereby the internal combustion engine 10 The temperature of the engine is maintained at a temperature suitable for engine operation. In other words, if the temperature of the internal combustion engine 10 rises excessively, piston seizure or the like occurs. On the other hand, if the temperature drops excessively, the combustion state deteriorates and the driving resistance increases, and as a result, the fuel consumption resulting from them deteriorates. It becomes. For this reason, this cooling device keeps the temperature of the engine cooling water in a predetermined temperature range, thereby suppressing such an excessive increase or decrease in the engine temperature.

ところで、内燃機関の燃焼熱量は機関運転状態に応じて変化するため、機関冷却水温ＴＨＷを所定の温度範囲に維持して機関温度を機関運転に適した温度に維持するためには、こうした燃焼熱量の変化に応じてラジエータ２２の放熱量を変更する必要がある。そこで、本実施形態の冷却装置では、電動ウォータポンプ２１と電動ファン２３の駆動状態を機関水温センサ５１によって検出される機関冷却水温ＴＨＷに基づいて変更し、ラジエータ２２の放熱量を調節するようにしている。 By the way, since the combustion heat quantity of the internal combustion engine changes according to the engine operating state, in order to maintain the engine cooling water temperature THW in a predetermined temperature range and maintain the engine temperature at a temperature suitable for engine operation, such combustion heat quantity is required. It is necessary to change the heat radiation amount of the radiator 22 in accordance with the change of the radiator. Therefore, in the cooling device of the present embodiment, the driving state of the electric water pump 21 and the electric fan 23 is changed based on the engine cooling water temperature THW detected by the engine water temperature sensor 51 to adjust the heat radiation amount of the radiator 22. ing.

こうした駆動電力の制御は電子制御装置５０によって行われる。電子制御装置５０には、図１に示されるように機関水温センサ５１、第１冷却系２０ａの還流通路２８ａに設けられた水温センサ５２ａ、第２冷却系２０ｂの還流通路２８ｂに設けられた水温センサ５２ｂの他、機関回転速度ＮＥを検出する回転速度センサ５３、内燃機関１０の吸入空気量ＧＡを検出するエアフロメータ５４等が接続されており、これら各種センサ５１〜５４の検出信号が取り込まれる。この電子制御装置５０は、各種センサ５１〜５４から取り込んだ検出値に基づいて第１冷却系２０ａ及び第２冷却系２０ｂにおける電動ウォータポンプ２１及び電動ファン２３の駆動電力を制御する。 Such control of driving power is performed by the electronic control unit 50. As shown in FIG. 1, the electronic control unit 50 includes an engine water temperature sensor 51, a water temperature sensor 52a provided in the return passage 28a of the first cooling system 20a, and a water temperature provided in the return passage 28b of the second cooling system 20b. In addition to the sensor 52b, a rotational speed sensor 53 for detecting the engine rotational speed NE, an air flow meter 54 for detecting the intake air amount GA of the internal combustion engine 10, and the like are connected, and detection signals of these various sensors 51 to 54 are captured. . The electronic control unit 50 controls the driving power of the electric water pump 21 and the electric fan 23 in the first cooling system 20a and the second cooling system 20b based on the detection values acquired from the various sensors 51 to 54.

ここで、本実施形態の冷却装置のように、電動ファン２３と電動ウォータポンプ２１とを備える車載内燃機関の冷却装置にあっては、これらを駆動するために電力が消費されるため、その電力消費量の増大を極力抑制することが重要となる。そこで、本実施形態の冷却装置では、機関冷却水温ＴＨＷ、車両走行風の風量、外気温等、車両運転状態や電動ファン２３及び電動ウォータポンプ２１の各駆動状態により即した態様でラジエータ２２の放熱量を効率的に制御することにより、これら電動ファン２３及び電動ウォータポンプ２１電力消費量の増大を抑制するようにしている。具体的には、第１冷却系２０ａにおける電動ファン２３ａの駆動電力のみを変化させたときの単位電力当たりの放熱量の変化量と、第２冷却系２０ｂにおける電動ウォータポンプ２１ｂの駆動電力のみを変化させたときの単位電力当たりの放熱量の変化量を比較する比較処理を実行し、その比較結果に基づいて冷却系全体の電力消費量が小さくなるように冷却系２０ａ，２０ｂの電動ファン２３及び電動ウォータポンプ２１の駆動電力を変更するようにしている。 Here, in the cooling device for an on-vehicle internal combustion engine including the electric fan 23 and the electric water pump 21 as in the cooling device of the present embodiment, electric power is consumed to drive them. It is important to suppress the increase in consumption as much as possible. Therefore, in the cooling device of the present embodiment, the radiator 22 is released in a manner that is more appropriate to the vehicle operating state and the driving states of the electric fan 23 and the electric water pump 21 such as the engine cooling water temperature THW, the air volume of the vehicle traveling wind, and the outside air temperature. By controlling the amount of heat efficiently, the electric fan 23 and the electric water pump 21 are prevented from increasing in power consumption. Specifically, only the amount of change in the heat dissipation amount per unit power when only the driving power of the electric fan 23a in the first cooling system 20a is changed, and the driving power of the electric water pump 21b in the second cooling system 20b. A comparison process for comparing the amount of change in the amount of heat radiation per unit power when changed is performed, and the electric fans 23 of the cooling systems 20a and 20b are reduced so that the power consumption of the entire cooling system is reduced based on the comparison result. And the drive electric power of the electric water pump 21 is changed.

以下、この比較処理を含め、電動ファン２３及び電動ウォータポンプ２１の駆動電力を制御する際の制御態様について図２〜図７を参照して説明する。図２及び図３は、電動ファン２３及び電動ウォータポンプ２１の駆動電力を制御する処理の一連の流れを示すフローチャートである。この処理は、機関運転中に機関冷却水温ＴＨＷが所定の温度以上となり、サーモスタットバルブ３０によって循環経路が切り替えられて第１冷却系２０ａ及び第２冷却系２０ｂのラジエータ２２を介して機関冷却水が循環される状態にあることを条件に、電子制御装置５０によって予め設定された所定期間Ｔｉｎｔ毎に繰り返し実行される。 Hereinafter, control modes for controlling the driving power of the electric fan 23 and the electric water pump 21 including this comparison processing will be described with reference to FIGS. 2 and 3 are flowcharts showing a series of processes for controlling the driving power of the electric fan 23 and the electric water pump 21. FIG. In this process, the engine cooling water temperature THW becomes equal to or higher than a predetermined temperature during engine operation, and the circulation path is switched by the thermostat valve 30 so that the engine cooling water flows through the radiators 22 of the first cooling system 20a and the second cooling system 20b. It is repeatedly executed every predetermined period Tint set in advance by the electronic control unit 50 on condition that it is in a circulating state.

この処理が開始されると、まずステップＳ１００において、機関水温センサ５１によって検出される機関冷却水温ＴＨＷが比較処理下限水温ＴＨＷｍｉｎ以上であるか否かが判定される。尚、比較処理下限水温ＴＨＷｍｉｎは、比較処理を実行する温度域の下限値として、例えば、機関運転に適した機関冷却水温の下限値が設定されている。 When this process is started, first, at step S100, it is determined whether or not the engine cooling water temperature THW detected by the engine water temperature sensor 51 is equal to or higher than the comparison processing lower limit water temperature THWmin. The comparison process lower limit water temperature THWmin is set to, for example, a lower limit value of the engine cooling water temperature suitable for engine operation as the lower limit value of the temperature range in which the comparison process is executed.

ステップＳ１００において、機関冷却水温ＴＨＷが比較処理下限水温ＴＨＷｍｉｎ未満である旨推定された場合には（ステップＳ１００：ＮＯ）、ステップＳ２００へと進む。そして、ステップＳ２００において、電動ファン２３を停止し、電子制御装置５０のメモリに予め記憶された演算マップを参照して機関運転状態に応じた電動ウォータポンプ２１の駆動電力を演算し、電動ウォータポンプ２１を駆動制御する。即ち、機関冷却水温ＴＨＷが機関運転に適した温度域以下であり、速やかに機関冷却水温ＴＨＷを上昇させる必要がある場合には、比較処理を実行せずに機関運転状態に基づいて予め決められた駆動電力にて電動ウォータポンプ２１を駆動する。 If it is estimated in step S100 that the engine cooling water temperature THW is lower than the comparison processing lower limit water temperature THWmin (step S100: NO), the process proceeds to step S200. In step S200, the electric fan 23 is stopped, the driving power of the electric water pump 21 according to the engine operating state is calculated with reference to the calculation map stored in advance in the memory of the electronic control unit 50, and the electric water pump 21 is driven and controlled. That is, when the engine coolant temperature THW is below the temperature range suitable for engine operation and the engine coolant temperature THW needs to be quickly raised, it is determined in advance based on the engine operating state without executing the comparison process. The electric water pump 21 is driven with the drive power.

尚、このとき参照される演算マップは、図４に示されるように、機関冷却水温ＴＨＷが高いときほど、また吸入空気量ＧＡ、機関回転速度ＮＥに基づいて算出される機関負荷が高く、内燃機関１０の燃焼熱量が多いときほど電動ウォータポンプ２１の駆動電力が大きくなるように設定されている。従って、機関負荷が高いときほど、また機関冷却水温ＴＨＷが高いときほど、電動ウォータポンプ２１の吐出量は多くなる。 As shown in FIG. 4, the calculation map referred to at this time has a higher engine load calculated based on the intake air amount GA and the engine rotational speed NE as the engine coolant temperature THW is higher, and the internal combustion engine temperature is increased. It is set so that the drive power of the electric water pump 21 increases as the combustion heat amount of the engine 10 increases. Therefore, the discharge amount of the electric water pump 21 increases as the engine load is higher and as the engine coolant temperature THW is higher.

ステップＳ２００において、演算マップを参照して電動ウォータポンプ２１の駆動電力を変更した後、この処理を一旦終了する。
一方、ステップＳ１００において、機関冷却水温ＴＨＷが比較処理下限温度ＴＨＷｍｉｎ以上である旨判定された場合には（ステップＳ１００：ＹＥＳ）、ステップＳ１１０へと進み、ステップＳ１１０において、機関冷却水温ＴＨＷが比較処理上限水温ＴＨＷｍａｘ以下であるか否かが判定される。尚、比較処理上限水温ＴＨＷｍａｘは、比較処理を実行する温度域の上限値として、例えば、機関運転に適した機関冷却水温の上限値が設定されている。 In step S200, the driving power of the electric water pump 21 is changed with reference to the calculation map, and then this process is temporarily terminated.
On the other hand, if it is determined in step S100 that the engine coolant temperature THW is equal to or higher than the comparison process lower limit temperature THWmin (step S100: YES), the process proceeds to step S110, and in step S110, the engine coolant temperature THW is compared. It is determined whether or not the upper limit water temperature is THWmax or less. Note that the upper limit value of the engine cooling water temperature suitable for engine operation is set as the upper limit value of the temperature range in which the comparison process is performed, for example, as the upper limit value of the comparison process upper limit water temperature THWmax.

ステップＳ１１０において、機関冷却水温ＴＨＷが比較処理上限水温ＴＨＷｍａｘよりも高い旨判定された場合（ステップＳ１１０：ＮＯ）、即ち機関冷却水温ＴＨＷが機関運転に適した温度域を超えて高くなっており、直ちに機関冷却水温ＴＨＷを低下させる必要がある旨判定された場合には、ステップＳ３００へと進む。そして、ステップＳ３００において、電動ファン２３及び電動ウォータポンプ２１の駆動電力をその最大値に設定することにより、電動ファン２３を最大送風量で駆動させるとともに、電動ウォータポンプ２１を最大吐出量で駆動させ、この処理を終了する。 In step S110, when it is determined that the engine cooling water temperature THW is higher than the comparison processing upper limit water temperature THWmax (step S110: NO), that is, the engine cooling water temperature THW is higher than the temperature range suitable for engine operation. If it is immediately determined that the engine coolant temperature THW needs to be reduced, the process proceeds to step S300. In step S300, the driving power of the electric fan 23 and the electric water pump 21 is set to the maximum value, so that the electric fan 23 is driven with the maximum blowing amount and the electric water pump 21 is driven with the maximum discharge amount. This process is terminated.

一方、ステップＳ１１０において、機関冷却水温ＴＨＷが比較処理上限水温ＴＨＷｍａｘ以下である旨判定された場合（ステップＳ１１０：ＹＥＳ）、即ち機関冷却水温ＴＨＷが比較処理下限水温ＴＨＷｍｉｎ以上であり、且つ比較処理上限水温ＴＨＷｍａｘ未満である旨判定された場合には、図３に示されるステップＳ１３０へと進む。そして、ステップＳ１３０において、機関冷却水温ＴＨＷが上昇中か否かが判定される。具体的には、前回の制御周期における機関冷却水温ＴＨＷと今回の制御周期における機関冷却水温ＴＨＷとを比較し、今回の制御周期における機関冷却水温ＴＨＷが前回の制御周期における機関冷却水温ＴＨＷよりも所定量以上高い場合には、機関冷却水温ＴＨＷが上昇中である旨判定される。 On the other hand, when it is determined in step S110 that the engine cooling water temperature THW is equal to or lower than the comparison processing upper limit water temperature THWmax (step S110: YES), that is, the engine cooling water temperature THW is equal to or higher than the comparison processing lower limit water temperature THWmin, and the comparison processing upper limit is set. When it is determined that the water temperature is lower than THWmax, the process proceeds to step S130 shown in FIG. In step S130, it is determined whether the engine coolant temperature THW is increasing. Specifically, the engine coolant temperature THW in the previous control cycle is compared with the engine coolant temperature THW in the current control cycle, and the engine coolant temperature THW in the current control cycle is greater than the engine coolant temperature THW in the previous control cycle. If it is higher than the predetermined amount, it is determined that the engine coolant temperature THW is increasing.

ステップＳ１３０において、機関冷却水温ＴＨＷが上昇中である旨判定された場合（ステップＳ１３０：ＹＥＳ）、換言すると各ラジエータ２２の放熱量を増大させて各冷却系２０ａ，２０ｂ全体の冷却能力を増大させる必要がある場合には、ステップＳ１４０へと進み、電動ウォータポンプ２１が最大吐出量で駆動されているか否かが判定される。そして、ステップＳ１４０において、電動ウォータポンプ２１が最大吐出量で駆動されている旨判定された場合には（ステップＳ１４０：ＹＥＳ）、ステップＳ１８０へと進み、ステップＳ１８０において、第１冷却系２０ａ及び第２冷却系２０ｂにおける電動ファン２３の駆動電力をそれぞれ所定量αだけ増大させる。即ち、これ以上電動ウォータポンプ２１の駆動電力を増大させることができないため、電動ファン２３の駆動電力を増大させることにより、ラジエータ２２の放熱量を増大させる。 If it is determined in step S130 that the engine coolant temperature THW is increasing (step S130: YES), in other words, the heat radiation amount of each radiator 22 is increased to increase the cooling capacity of the entire cooling systems 20a and 20b. If necessary, the process proceeds to step S140, and it is determined whether or not the electric water pump 21 is driven at the maximum discharge amount. If it is determined in step S140 that the electric water pump 21 is driven at the maximum discharge amount (step S140: YES), the process proceeds to step S180, and in step S180, the first cooling system 20a and the first The driving power of the electric fan 23 in the two cooling system 20b is increased by a predetermined amount α. That is, since the drive power of the electric water pump 21 cannot be increased any more, the heat dissipation amount of the radiator 22 is increased by increasing the drive power of the electric fan 23.

尚、所定量αは、同所定量αだけ駆動電力を増大させることにより、第１冷却系２０ａに設けられた水温センサ５２ａによって検出される水温ＴＨＷ１（以下、「水温ＴＨＷ１」という）と、第２冷却系２０ｂに設けられた水温センサ５２ｂによって検出される水温ＴＨＷ２（以下、「水温ＴＨＷ２」という）とを変化させることのできる駆動電力の変更量の最小値よりも大きな値に設定されている。こうして第１冷却系２０ａ及び第２冷却系２０ｂにおける電動ファン２３の駆動電力を増大させた後、この処理を一旦終了する。 Note that the predetermined amount α is obtained by increasing the driving power by the predetermined amount α to detect the water temperature THW1 (hereinafter referred to as “water temperature THW1”) detected by the water temperature sensor 52a provided in the first cooling system 20a. 2 is set to a value larger than the minimum value of the change amount of the driving power that can change the water temperature THW2 (hereinafter referred to as “water temperature THW2”) detected by the water temperature sensor 52b provided in the cooling system 20b. . After increasing the driving power of the electric fan 23 in the first cooling system 20a and the second cooling system 20b in this way, this process is temporarily terminated.

一方、ステップＳ１４０において、電動ウォータポンプ２１が最大吐出量で駆動されていない旨判定された場合には（ステップＳ１４０：ＮＯ）、ステップＳ１５０へと進み、電動ファン２３が最大送風量で駆動されているか否かが判定される。 On the other hand, when it is determined in step S140 that the electric water pump 21 is not driven with the maximum discharge amount (step S140: NO), the process proceeds to step S150, and the electric fan 23 is driven with the maximum air flow rate. It is determined whether or not there is.

ステップＳ１５０において、電動ファン２３が最大吐出量で駆動されている旨判定された場合には（ステップＳ１５０：ＹＥＳ）、ステップＳ１８２へと進み、ステップＳ１８２において、第１冷却系２０ａ及び第２冷却系２０ｂにおける電動ウォータポンプ２１の駆動電力をそれぞれ所定量αだけ増大させる。即ち、これ以上電動ファン２３の駆動電力を増大させることができないため、電動ウォータポンプ２１の駆動電力を増大させてその吐出量を増大させることにより、ラジエータ２２の放熱量を増大させる。こうして電動ウォータポンプ２１の駆動電力を増大させた後、この処理を一旦終了する。 If it is determined in step S150 that the electric fan 23 is driven with the maximum discharge amount (step S150: YES), the process proceeds to step S182, and in step S182, the first cooling system 20a and the second cooling system are processed. The driving power of the electric water pump 21 at 20b is increased by a predetermined amount α. That is, since the drive power of the electric fan 23 cannot be increased any more, the heat dissipation amount of the radiator 22 is increased by increasing the drive power of the electric water pump 21 and increasing the discharge amount. After increasing the driving power of the electric water pump 21 in this way, this process is temporarily terminated.

これに対して、ステップＳ１５０において、電動ファン２３が最大送風量で駆動されていない旨判定された場合には（ステップＳ１５０：ＮＯ）、ステップＳ１６０へと進む。
ステップＳ１６０では、第１冷却系２０ａにおける電動ファン２３ａ及び電動ウォータポンプ２１ａのうち電動ファン２３ａの駆動電力のみを所定量αだけ増大させるとともに、第２冷却系２０ｂにおける電動ファン２３ｂ及び電動ウォータポンプ２１ｂのうち電動ウォータポンプ２１ｂの駆動電力のみを同じく所定量αだけ増大させる。こうしてステップＳ１６０を通じて電動ファン２３ａ及び電動ウォータポンプ２１ｂの駆動電力をそれぞれ所定量αだけ増大させた後、水温ＴＨＷ１及び水温ＴＨＷ２が変化するまで予め設定された所定の期間だけ待ってステップＳ１７０へと進む。 On the other hand, when it is determined in step S150 that the electric fan 23 is not driven with the maximum air flow (step S150: NO), the process proceeds to step S160.
In step S160, only the driving power of the electric fan 23a in the first cooling system 20a and the electric water pump 21a is increased by a predetermined amount α, and the electric fan 23b and the electric water pump 21b in the second cooling system 20b are increased. Among them, only the driving power of the electric water pump 21b is similarly increased by a predetermined amount α. Thus, after the drive power of the electric fan 23a and the electric water pump 21b is increased by a predetermined amount α through the step S160, the process proceeds to the step S170 after waiting for a predetermined period until the water temperature THW1 and the water temperature THW2 change. .

ステップＳ１７０では、水温ＴＨＷ１と、水温ＴＨＷ２とが比較され、水温ＴＨＷ１が水温ＴＨＷ２よりも低いか否かが判定される。
内燃機関１０のウォータジャケット１２から排出され、排出通路２５を通じて各冷却系２０ａ，２０ｂのラジエータ２２に供給される機関冷却水の温度は等しい。そのため、ラジエータ２２ａから送出された機関冷却水の温度（水温ＴＨＷ１）と、ラジエータ２２ｂから送出された機関冷却水の温度（水温ＴＨＷ２）とを比較することにより、ラジエータ２２ａとラジエータ２２ｂとの放熱量の大小を比較することができ、ひいては単位電力当たりの放熱量の変化量を比較することができる。 In step S170, the water temperature THW1 is compared with the water temperature THW2, and it is determined whether or not the water temperature THW1 is lower than the water temperature THW2.
The temperature of the engine coolant discharged from the water jacket 12 of the internal combustion engine 10 and supplied to the radiator 22 of each cooling system 20a, 20b through the discharge passage 25 is equal. Therefore, by comparing the temperature of the engine cooling water sent from the radiator 22a (water temperature THW1) and the temperature of the engine cooling water sent from the radiator 22b (water temperature THW2), the amount of heat released between the radiator 22a and the radiator 22b. Can be compared, and as a result, the amount of change in heat radiation per unit power can be compared.

より具体的には、水温ＴＨＷ１が水温ＴＨＷ２よりも低い場合には、電動ファン２３ａの駆動電力を所定量αだけ増大させた第１冷却系２０ａのラジエータ２２ａにおける放熱量の変化量が、電動ウォータポンプ２１ｂの駆動電力を所定量αだけ増大させた第２冷却系２０ｂのラジエータ２２ｂにおける放熱量の変化量よりも大きい旨推定することができる。その結果、この比較処理が行われた時点において、電動ファン２３と電動ウォータポンプ２１のうち電動ファン２３の方が単位電力当たりの放熱量の変化量が大きい旨判定することができる。 More specifically, when the water temperature THW1 is lower than the water temperature THW2, the amount of change in the heat radiation amount in the radiator 22a of the first cooling system 20a obtained by increasing the drive power of the electric fan 23a by a predetermined amount α is the electric water. It can be estimated that the amount of heat dissipation in the radiator 22b of the second cooling system 20b in which the driving power of the pump 21b is increased by a predetermined amount α is larger. As a result, when this comparison process is performed, it can be determined that the electric fan 23 of the electric fan 23 and the electric water pump 21 has a larger amount of change in the heat radiation amount per unit power.

ステップＳ１７０において、水温ＴＨＷ１が水温ＴＨＷ２よりも低い旨判定された場合（ステップＳ１７０：ＹＥＳ）、即ち電動ファン２３と電動ウォータポンプ２１のうち電動ファン２３の方が単位電力当たりの放熱量の変化量が大きい旨判定された場合には、ステップＳ１８０へと進み。ステップＳ１６０において増大させた電動ウォータポンプ２１ｂの駆動電力を所定量αだけ減少させて元に戻すとともに、第２冷却系２０ｂにおける電動ファン２３ｂの駆動電力を所定量αだけ増大させる。即ち、ステップＳ１６０において駆動電力を増大させる直前の状態に対して第１冷却系２０ａ及び第２冷却系２０ｂの双方の電動ファン２３の駆動電力をそれぞれ所定量αだけ増大させる。こうして第１冷却系２０ａ及び第２冷却系２０ｂにおける電動ファン２３の駆動電力をそれぞれ所定量αだけ増大させ、ラジエータ２２の放熱量を増大させた後、この処理を一旦終了する。 In step S170, when it is determined that the water temperature THW1 is lower than the water temperature THW2 (step S170: YES), that is, the electric fan 23 of the electric fan 23 and the electric water pump 21 changes the amount of heat radiation per unit power. If it is determined that is large, the process proceeds to step S180. The drive power of the electric water pump 21b increased in step S160 is reduced by a predetermined amount α and returned to the original state, and the drive power of the electric fan 23b in the second cooling system 20b is increased by a predetermined amount α. That is, the driving power of the electric fans 23 of both the first cooling system 20a and the second cooling system 20b is increased by a predetermined amount α with respect to the state immediately before the driving power is increased in step S160. In this way, the driving power of the electric fan 23 in the first cooling system 20a and the second cooling system 20b is increased by a predetermined amount α, and the heat dissipation amount of the radiator 22 is increased.

一方、ステップＳ１７０において、水温ＴＨＷ１が水温ＴＨＷ２以上である旨判定された場合（ステップＳ１７０：ＮＯ）、即ち電動ファン２３の単位電力当たりの放熱量の変化量が電動ウォータポンプ２１の単位電力当たりの放熱量の変化量以下である旨判定された場合には、ステップＳ１８２へと進む。そして、ステップＳ１８２では、ステップＳ１６０において増大させた電動ファン２３ａの駆動電力を所定量αだけ減少させて元に戻すとともに、第１冷却系２０ａにおける電動ウォータポンプ２１ａの駆動電力を所定量αだけ増大させる。即ち、ステップＳ１６０において駆動電力を増大させる直前の状態に対して第１冷却系２０ａ及び第２冷却系２０ｂの双方の電動ウォータポンプ２１の駆動電力をそれぞれ所定量αだけ増大させる。こうして第１冷却系２０ａ及び第２冷却系２０ｂにおける電動ウォータポンプ２１の駆動電力をそれぞれ所定量αだけ増大させ、ラジエータ２２の放熱量を増大させた後、この処理を一旦終了する。 On the other hand, when it is determined in step S170 that the water temperature THW1 is equal to or higher than the water temperature THW2 (step S170: NO), that is, the amount of change in the heat dissipation amount per unit power of the electric fan 23 is per unit power of the electric water pump 21. If it is determined that the amount of change is not more than the amount of change in the heat dissipation amount, the process proceeds to step S182. In step S182, the driving power of the electric fan 23a increased in step S160 is decreased by a predetermined amount α and returned to the original state, and the driving power of the electric water pump 21a in the first cooling system 20a is increased by a predetermined amount α. Let That is, the driving power of the electric water pumps 21 of both the first cooling system 20a and the second cooling system 20b is increased by a predetermined amount α with respect to the state immediately before the driving power is increased in step S160. In this way, the driving power of the electric water pump 21 in the first cooling system 20a and the second cooling system 20b is increased by a predetermined amount α, and the heat radiation amount of the radiator 22 is increased.

これに対して、ステップＳ１３０において、機関冷却水温ＴＨＷが上昇中ではない旨判定された場合には（ステップＳ１３０：ＮＯ）、ステップＳ１４５へと進み、ステップＳ１４５において、機関冷却水温ＴＨＷが低下中か否かが判定される。具体的にはこの判定は、ステップＳ１３０の処理と同様、前回の制御周期における機関冷却水温ＴＨＷと今回の制御周期における機関冷却水温ＴＨＷとを比較し、今回の制御周期における機関冷却水温ＴＨＷが前回の制御周期における機関冷却水温ＴＨＷよりも所定量以上低い場合には、機関冷却水温ＴＨＷが低下中である旨判定される。 In contrast, if it is determined in step S130 that the engine coolant temperature THW is not increasing (step S130: NO), the process proceeds to step S145, and in step S145, whether the engine coolant temperature THW is decreasing. It is determined whether or not. Specifically, in this determination, as in the process of step S130, the engine cooling water temperature THW in the previous control cycle is compared with the engine cooling water temperature THW in the current control cycle, and the engine cooling water temperature THW in the current control cycle is compared with the previous time. When the engine coolant temperature THW is lower than the engine coolant temperature THW in the control cycle by a predetermined amount or more, it is determined that the engine coolant temperature THW is decreasing.

ステップＳ１４５において、機関冷却水温ＴＨＷが低下中である旨判定された場合（ステップＳ１４５：ＹＥＳ）、換言すると各ラジエータ２２の放熱量を減少させて各冷却系２０ａ，２０ｂ全体の冷却能力を低下させる必要がある場合には、ステップＳ１５５へと進み、電動ファン２３が停止しているか否かが判定される。ステップＳ１５５において、電動ファン２３が停止している旨判定された場合には（ステップＳ１５５：ＹＥＳ）、ステップＳ１８６へと進み、ステップＳ１８６において、第１冷却系２０ａ及び第２冷却系２０ｂにおける電動ウォータポンプ２１の駆動電力をそれぞれ所定量αだけ減少させる。即ち、これ以上電動ファン２３の駆動電力を減少させることができないため、電動ウォータポンプ２１の駆動電力を減少させてその吐出量を減少させることにより、ラジエータ２２の放熱量を減少させる。こうして電動ウォータポンプ２１の駆動電力を減少させた後、この処理を一旦終了する。 When it is determined in step S145 that the engine coolant temperature THW is decreasing (step S145: YES), in other words, the heat radiation amount of each radiator 22 is decreased to reduce the cooling capacity of the entire cooling systems 20a and 20b. If necessary, the process proceeds to step S155, and it is determined whether or not the electric fan 23 is stopped. When it is determined in step S155 that the electric fan 23 is stopped (step S155: YES), the process proceeds to step S186, and in step S186, the electric water in the first cooling system 20a and the second cooling system 20b. The driving power of the pump 21 is decreased by a predetermined amount α. That is, since the drive power of the electric fan 23 cannot be reduced any more, the heat dissipation amount of the radiator 22 is reduced by reducing the drive power of the electric water pump 21 and reducing the discharge amount. After the drive power of the electric water pump 21 is reduced in this way, this process is temporarily terminated.

一方、電動ファン２３が停止されていない旨判定された場合には（ステップＳ１５５：ＮＯ）、ステップＳ１６５へと進む。
ステップＳ１６５では、第１冷却系２０ａにおける電動ファン２３ａ及び電動ウォータポンプ２１ａのうち電動ファン２３ａの駆動電力のみを所定量αだけ減少させるとともに、第２冷却系２０ｂにおける電動ファン２３ｂ及び電動ウォータポンプ２１ｂのうち電動ウォータポンプ２１ｂの駆動電力のみを同じく所定量αだけ減少させる。 On the other hand, when it is determined that the electric fan 23 is not stopped (step S155: NO), the process proceeds to step S165.
In step S165, only the driving power of the electric fan 23a in the first cooling system 20a and the electric water pump 21a is reduced by a predetermined amount α, and the electric fan 23b and the electric water pump 21b in the second cooling system 20b are reduced. Among them, only the driving power of the electric water pump 21b is similarly reduced by a predetermined amount α.

こうしてステップＳ１６５を通じて電動ファン２３ａ及び電動ウォータポンプ２１ｂの駆動電力をそれぞれ所定量αだけ減少させた後、水温ＴＨＷ１及び水温ＴＨＷ２が変化するまで予め設定された所定の期間だけ待ってステップＳ１７５へと進む。 Thus, after the drive power of the electric fan 23a and the electric water pump 21b is decreased by a predetermined amount α through step S165, the process waits for a predetermined period until the water temperature THW1 and the water temperature THW2 change, and then proceeds to step S175. .

ステップＳ１７５では、水温ＴＨＷ１と、水温ＴＨＷ２とが比較され、水温ＴＨＷ１が水温ＴＨＷ２よりも低いか否かが判定される。
上述したように水温ＴＨＷ１と水温ＴＨＷ２とを比較することにより、ラジエータ２２ａとラジエータ２２ｂとの放熱量の大小を比較することができる。具体的には、水温ＴＨＷ１が水温ＴＨＷ２よりも低い場合には、電動ファン２３ａの駆動電力を所定量αだけ減少させた第１冷却系２０ａのラジエータ２２ａにおける放熱量の変化量が、電動ウォータポンプ２１ｂの駆動電力を所定量αだけ減少させた第２冷却系２０ｂのラジエータ２２ｂにおける放熱量の変化量よりも小さい旨推定することができる。その結果、この比較処理が行われた時点において、電動ファン２３と電動ウォータポンプ２１のうち電動ファン２３の方が単位電力当たりの放熱量の変化量が小さい旨判定することができる。 In step S175, the water temperature THW1 is compared with the water temperature THW2, and it is determined whether or not the water temperature THW1 is lower than the water temperature THW2.
As described above, by comparing the water temperature THW1 and the water temperature THW2, it is possible to compare the amount of heat radiation between the radiator 22a and the radiator 22b. Specifically, when the water temperature THW1 is lower than the water temperature THW2, the amount of change in the amount of heat radiation in the radiator 22a of the first cooling system 20a obtained by reducing the drive power of the electric fan 23a by a predetermined amount α is the electric water pump. It can be estimated that the amount of heat radiation in the radiator 22b of the second cooling system 20b, in which the driving power of 21b is reduced by a predetermined amount α, is smaller than the amount of change. As a result, when this comparison process is performed, it can be determined that the electric fan 23 of the electric fan 23 and the electric water pump 21 has a smaller amount of change in the heat radiation amount per unit power.

ステップＳ１７５において、水温ＴＨＷ１が水温ＴＨＷ２よりも低い旨判定された場合（ステップＳ１７５：ＹＥＳ）、即ち電動ファン２３と電動ウォータポンプ２１のうち電動ファン２３の方が単位電力当たりの放熱量の変化量が小さい旨判定された場合には、ステップＳ１８４へと進み。ステップＳ１６５において減少させた電動ウォータポンプ２１ｂの駆動電力を所定量αだけ増大させて元に戻すとともに、第２冷却系２０ｂにおける電動ファン２３ｂの駆動電力を所定量αだけ減少させる。即ち、ステップＳ１６５において駆動電力を減少させる直前の状態に対して第１冷却系２０ａ及び第２冷却系２０ｂの双方の電動ファン２３の駆動電力をそれぞれ所定量αだけ減少させる。こうして第１冷却系２０ａ及び第２冷却系２０ｂにおける電動ファン２３の駆動電力をそれぞれ所定量αだけ減少させ、ラジエータ２２の放熱量を増大させた後、この処理を一旦終了する。 When it is determined in step S175 that the water temperature THW1 is lower than the water temperature THW2 (step S175: YES), that is, the electric fan 23 of the electric fan 23 and the electric water pump 21 changes the amount of heat released per unit power. If it is determined that is small, the process proceeds to step S184. The drive power of the electric water pump 21b decreased in step S165 is increased by a predetermined amount α and returned to the original state, and the drive power of the electric fan 23b in the second cooling system 20b is decreased by a predetermined amount α. That is, in step S165, the driving power of the electric fans 23 of both the first cooling system 20a and the second cooling system 20b is decreased by a predetermined amount α with respect to the state immediately before the driving power is decreased. In this way, the driving power of the electric fan 23 in the first cooling system 20a and the second cooling system 20b is decreased by a predetermined amount α, and the heat dissipation amount of the radiator 22 is increased.

一方、ステップＳ１７５において、水温ＴＨＷ１が水温ＴＨＷ２以上である旨判定された場合（ステップＳ１７５：ＮＯ）、即ち電動ファン２３の単位電力当たりの放熱量の変化量が電動ウォータポンプ２１の単位電力当たりの放熱量の変化量以上である旨判定された場合には、ステップＳ１８６へと進む。そして、ステップＳ１８６では、ステップＳ１６５において減少させた電動ファン２３ａの駆動電力を所定量αだけ増大させて元に戻すとともに、第１冷却系２０ａにおける電動ウォータポンプ２１ａの駆動電力を所定量αだけ減少させる。即ち、ステップＳ１６５において駆動電力を減少させる直前の状態に対して第１冷却系２０ａ及び第２冷却系２０ｂの双方の電動ウォータポンプ２１の駆動電力をそれぞれ所定量αだけ減少させる。こうして第１冷却系２０ａ及び第２冷却系２０ｂにおける電動ウォータポンプ２１の駆動電力をそれぞれ所定量αだけ減少させ、ラジエータ２２の放熱量を減少させた後、この処理を一旦終了する。 On the other hand, when it is determined in step S175 that the water temperature THW1 is equal to or higher than the water temperature THW2 (step S175: NO), that is, the amount of change in the heat dissipation amount per unit power of the electric fan 23 is per unit power of the electric water pump 21. If it is determined that the amount of change is greater than the amount of change in the heat dissipation amount, the process proceeds to step S186. In step S186, the driving power of the electric fan 23a decreased in step S165 is increased by a predetermined amount α and returned to the original state, and the driving power of the electric water pump 21a in the first cooling system 20a is decreased by a predetermined amount α. Let That is, in step S165, the driving power of the electric water pumps 21 of both the first cooling system 20a and the second cooling system 20b is decreased by a predetermined amount α with respect to the state immediately before the driving power is decreased. In this way, the driving power of the electric water pump 21 in each of the first cooling system 20a and the second cooling system 20b is decreased by a predetermined amount α, and the heat radiation amount of the radiator 22 is decreased.

これに対して、ステップＳ１４５において、機関冷却水温ＴＨＷが低下中ではない旨判定された場合（ステップＳ１４５：ＮＯ）、即ち前回の制御周期における機関冷却水温ＴＨＷと今回の制御周期における機関冷却水温ＴＨＷとの差が所定量よりも小さく、機関冷却水温ＴＨＷがあまり変化していない旨判定された場合には、電動ファン２３及び電動ウォータポンプ２１の駆動電力を変化させずにこの処理を一旦終了する。 On the other hand, when it is determined in step S145 that the engine coolant temperature THW is not decreasing (step S145: NO), that is, the engine coolant temperature THW in the previous control cycle and the engine coolant temperature THW in the current control cycle. Is smaller than the predetermined amount and it is determined that the engine coolant temperature THW has not changed so much, the process is temporarily terminated without changing the drive power of the electric fan 23 and the electric water pump 21. .

以下、この一連の処理を通じて制御される機関冷却水温ＴＨＷの変化について、図５〜７を参照して説明する。図５は、機関冷却水温ＴＨＷと、本実施形態の冷却装置における電動ファン２３及び電動ウォータポンプ２１の駆動電力の制御態様との関係を示している。 Hereinafter, changes in the engine coolant temperature THW controlled through this series of processes will be described with reference to FIGS. FIG. 5 shows the relationship between the engine coolant temperature THW and the control mode of the driving power of the electric fan 23 and the electric water pump 21 in the cooling device of the present embodiment.

図５に示されるように、機関冷却水温ＴＨＷが比較処理下限水温ＴＨＷｍｉｎ未満の場合には（時刻Ｔ１以前）、電動ファン２３は停止され、電動ウォータポンプ２１の駆動電力が演算マップを参照して設定される。時刻Ｔ１において、機関冷却水温ＴＨＷが比較処理下限水温ＴＨＷｍｉｎ以上であり、且つ機関冷却水温ＴＨＷが上昇中である旨判定されると、上述したように、第１冷却系２０ａにおける電動ファン２３ａと第２冷却系２０ｂにおける電動ウォータポンプ２１ｂの駆動電力を増大させて放熱量の変化量を比較する水温上昇時の比較処理が実行される。そして、この比較処理の結果に基づいて、電動ファン２３と電動ウォータポンプ２１のうち単位電力当たりの放熱量の変化量が大きい方の駆動電力が増大される。 As shown in FIG. 5, when the engine cooling water temperature THW is lower than the comparison processing lower limit water temperature THWmin (before time T1), the electric fan 23 is stopped and the driving power of the electric water pump 21 is referred to the calculation map. Is set. When it is determined at time T1 that the engine cooling water temperature THW is equal to or higher than the comparison processing lower limit water temperature THWmin and the engine cooling water temperature THW is increasing, as described above, the electric fan 23a in the first cooling system 20a and the first The comparison process at the time of the water temperature rise in which the drive power of the electric water pump 21b in the two cooling system 20b is increased to compare the amount of change in the heat radiation amount is executed. Then, based on the result of this comparison processing, the driving power having the larger amount of change in the heat dissipation amount per unit power of the electric fan 23 and the electric water pump 21 is increased.

こうした比較処理を繰り返し実行しながら電動ファン２３及び電動ウォータポンプ２１の駆動電力を増大させることにより、ラジエータ２２の放熱量が増大し、機関冷却水温ＴＨＷの変化量が次第に小さくなる。そして、時刻Ｔ２において機関冷却水温ＴＨＷがあまり変化していない旨判定されると、駆動電力はそのまま維持され、機関冷却水温ＴＨＷが機関運転に適した温度域に維持されるようになる。 By increasing the driving power of the electric fan 23 and the electric water pump 21 while repeatedly performing such comparison processing, the heat dissipation amount of the radiator 22 increases and the change amount of the engine cooling water temperature THW gradually decreases. When it is determined that the engine coolant temperature THW has not changed much at time T2, the drive power is maintained as it is, and the engine coolant temperature THW is maintained in a temperature range suitable for engine operation.

また、内燃機関１０の燃焼熱量が非常に大きい場合には、時刻Ｔ３以降のように、水温上昇時の比較処理が繰り返し実行され、電動ファン２３と電動ウォータポンプ２１の駆動電力が増大しているにも関わらず、機関冷却水温ＴＨＷが上昇し続ける。こうした場合には、機関冷却水温ＴＨＷが比較処理上限水温ＴＨＷｍａｘよりも高い旨判定されると（時刻Ｔ４）、電動ファン２３及び電動ウォータポンプ２１の駆動電力がともに最大値に設定され、電動ファン２３が最大送風量で駆動されるとともに、電動ウォータポンプ２１が最大吐出量で駆動される。こうしてラジエータ２２の放熱量が最大限増大されると、機関冷却水温ＴＨＷは、速やかに低下するようになる（時刻Ｔ４以降）。 Further, when the amount of heat of combustion of the internal combustion engine 10 is very large, the comparison processing at the time of the water temperature rise is repeatedly executed as after time T3, and the driving power of the electric fan 23 and the electric water pump 21 is increased. Nevertheless, the engine coolant temperature THW continues to rise. In such a case, when it is determined that the engine cooling water temperature THW is higher than the comparison processing upper limit water temperature THWmax (time T4), the drive power of the electric fan 23 and the electric water pump 21 are both set to the maximum value, and the electric fan 23 Is driven with the maximum air flow rate, and the electric water pump 21 is driven with the maximum discharge amount. When the heat radiation amount of the radiator 22 is increased to the maximum extent in this way, the engine cooling water temperature THW quickly decreases (after time T4).

そして、時刻Ｔ５において、機関冷却水温ＴＨＷが比較処理上限水温ＴＨＷｍａｘ以下になり、且つ機関冷却水温ＴＨＷが低下中である旨判定されると、上述したように、第１冷却系２０ａにおける電動ファン２３ａと第２冷却系２０ｂにおける電動ウォータポンプ２１ｂの駆動電力を減少させて放熱量の変化量を比較する水温低下時の比較処理が実行され、電動ファン２３と電動ウォータポンプ２１のうち単位電力当たりの放熱量の変化量が小さい方の駆動電力が減少される。 When it is determined at time T5 that the engine cooling water temperature THW is equal to or lower than the comparison processing upper limit water temperature THWmax and the engine cooling water temperature THW is decreasing, as described above, the electric fan 23a in the first cooling system 20a. And a comparison process at the time of water temperature reduction that compares the amount of change in heat radiation by reducing the driving power of the electric water pump 21b in the second cooling system 20b is performed, and the electric fan 23 and the electric water pump 21 per unit power The drive power with the smaller amount of change in heat dissipation is reduced.

こうした比較処理が繰り返し実行され、電動ファン２３と電動ウォータポンプ２１の駆動電力が減少されることにより、ラジエータ２２の放熱量が減少し、機関冷却水温ＴＨＷの変化量が小さくなる。そして、時刻Ｔ６において機関冷却水温ＴＨＷがあまり変化していない旨判定されると、駆動電力はそのまま維持され、機関冷却水温ＴＨＷが機関運転に適した温度域に維持されるようになる。 Such comparison processing is repeatedly executed, and the driving power of the electric fan 23 and the electric water pump 21 is reduced, so that the heat radiation amount of the radiator 22 is reduced and the change amount of the engine cooling water temperature THW is reduced. When it is determined at time T6 that the engine coolant temperature THW has not changed much, the drive power is maintained as it is, and the engine coolant temperature THW is maintained in a temperature range suitable for engine operation.

次に、水温上昇時の比較処理における電動ファン２３及び電動ウォータポンプ２１の駆動電力の変化について図６を参照して具体的に説明する。図６は、水温上昇時の比較処理による第１冷却系２０ａ及び第２冷却系２０ｂにおける電動ファン２３及び電動ウォータポンプ２１の駆動電力の変化と、水温ＴＨＷ１及び水温ＴＨＷ２の変化との関係を示している。尚、図６に示されるように、時刻ｔ１から時刻ｔ３までの所定期間Ｔｉｎｔが図２及び図３を参照して説明した一連の処理の制御周期に相当する。即ち、上述した処理は、所定期間Ｔｉｎｔ毎に図６における時刻ｔ１、ｔ３、ｔ５を開始タイミングとして実行される。 Next, changes in driving power of the electric fan 23 and the electric water pump 21 in the comparison process when the water temperature rises will be specifically described with reference to FIG. FIG. 6 shows the relationship between changes in the driving power of the electric fan 23 and the electric water pump 21 in the first cooling system 20a and the second cooling system 20b and the changes in the water temperature THW1 and the water temperature THW2 in the comparison process when the water temperature rises. ing. As shown in FIG. 6, a predetermined period Tint from time t1 to time t3 corresponds to a control cycle of a series of processes described with reference to FIGS. That is, the above-described processing is executed for each predetermined period Tint with the times t1, t3, and t5 in FIG. 6 as the start timing.

水温上昇時の比較処理が実行されると、図６に示されるように、まず時刻ｔ１において第１冷却系２０ａにおける電動ファン２３ａと第２冷却系２０ｂにおける電動ウォータポンプ２１ｂの駆動電力が所定量αだけ増大される。そして、時刻ｔ２において、図６において実線で示される水温ＴＨＷ１と破線で示される水温ＴＨＷ２とが比較される。ここでは、水温ＴＨＷ１が水温ＴＨＷ２以上である旨判定されるため、第１冷却系２０ａにおける電動ファン２３ａの駆動電力が所定量αだけ減少され、その一方で電動ウォータポンプ２１ａの駆動電力が所定量αだけ増大される。こうして時刻ｔ１における状態に対して第１冷却系２０ａ及び第２冷却系２０ｂにおける電動ウォータポンプ２１の駆動電力がそれぞれ所定量αだけ増大される。こうしてラジエータ２２の放熱量が増大すると機関冷却水温ＴＨＷの上昇量は減少する。 When the comparison process when the water temperature rises is executed, as shown in FIG. 6, first, at time t1, the driving power of the electric fan 23a in the first cooling system 20a and the electric water pump 21b in the second cooling system 20b is a predetermined amount. Increased by α. Then, at time t2, the water temperature THW1 indicated by the solid line in FIG. 6 is compared with the water temperature THW2 indicated by the broken line. Here, since it is determined that the water temperature THW1 is equal to or higher than the water temperature THW2, the driving power of the electric fan 23a in the first cooling system 20a is reduced by a predetermined amount α, while the driving power of the electric water pump 21a is predetermined amount. Increased by α. Thus, the driving power of the electric water pump 21 in the first cooling system 20a and the second cooling system 20b is increased by a predetermined amount α with respect to the state at time t1. Thus, when the amount of heat released from the radiator 22 increases, the amount of increase in the engine coolant temperature THW decreases.

そして、次の制御周期である時刻ｔ３において、機関冷却水温ＴＨＷが未だ上昇中である旨判定されると、再び比較処理が実行され、第１冷却系２０ａにおける電動ファン２３ａと第２冷却系２０ｂにおける電動ウォータポンプ２１ｂの駆動電力が所定量αだけ増大される。時刻ｔ４において、水温ＴＨＷ１と水温ＴＨＷ２とが比較され、水温ＴＨＷ１が水温ＴＨＷ２よりも低い旨判定されると、第２冷却系２０ｂにおける電動ウォータポンプ２１ｂの駆動電力が所定量αだけ減少され、その一方で電動ファン２３ｂの駆動電力が所定量αだけ増大される。こうして時刻ｔ３における状態に対して第１冷却系２０ａ及び第２冷却系２０ｂにおける電動ファン２３の駆動電力が所定量αだけそれぞれ増大される。こうしてラジエータ２２の放熱量が増大すると機関冷却水温ＴＨＷの上昇量は更に減少する。時刻ｔ５においても同様に水温上昇時の比較処理が実行され、時刻ｔ６において第１冷却系２０ａ及び第２冷却系２０ｂにおける電動ファン２３の駆動電力が所定量αだけ増大される。 When it is determined at time t3 that is the next control cycle that the engine coolant temperature THW is still rising, the comparison process is executed again, and the electric fan 23a and the second cooling system 20b in the first cooling system 20a are executed. The driving power of the electric water pump 21b is increased by a predetermined amount α. When the water temperature THW1 is compared with the water temperature THW2 at time t4 and it is determined that the water temperature THW1 is lower than the water temperature THW2, the drive power of the electric water pump 21b in the second cooling system 20b is decreased by a predetermined amount α, On the other hand, the driving power of the electric fan 23b is increased by a predetermined amount α. Thus, the driving power of the electric fan 23 in the first cooling system 20a and the second cooling system 20b is increased by a predetermined amount α with respect to the state at time t3. Thus, when the heat dissipation amount of the radiator 22 increases, the increase amount of the engine coolant temperature THW further decreases. Similarly, at time t5, the comparison process when the water temperature rises is executed, and at time t6, the driving power of the electric fan 23 in the first cooling system 20a and the second cooling system 20b is increased by a predetermined amount α.

機関冷却水温ＴＨＷが比較処理下限水温ＴＨＷｍｉｎ以上であり、且つ機関冷却水温ＴＨＷが上昇している場合には、このように電動ファン２３ａと電動ウォータポンプ２１ｂの駆動電力を所定量αだけ増大させる比較処理が所定期間Ｔｉｎｔ毎に繰り返し実行される。そして、その結果に基づいて第１冷却系２０ａ及び第２冷却系２０ｂの電動ファン２３又は電動ウォータポンプのうち単位電力当たりの放熱量の増大量が大きい方の駆動電力が選択的に増大される。こうして、ラジエータ２２の放熱量が徐々に増大され、機関冷却水温ＴＨＷの上昇量が減少して機関冷却水温ＴＨＷが所定の温度域に維持されるようになる。 When the engine cooling water temperature THW is equal to or higher than the comparison processing lower limit water temperature THWmin and the engine cooling water temperature THW is rising, the comparison is made to increase the drive power of the electric fan 23a and the electric water pump 21b by a predetermined amount α in this way. The process is repeatedly executed every predetermined period Tint. Based on the result, the driving power having the larger increase in the amount of heat radiation per unit power of the electric fan 23 or the electric water pump of the first cooling system 20a and the second cooling system 20b is selectively increased. . Thus, the amount of heat released from the radiator 22 is gradually increased, the amount of increase in the engine coolant temperature THW is decreased, and the engine coolant temperature THW is maintained in a predetermined temperature range.

次に、水温低下時の比較処理における電動ファン２３及び電動ウォータポンプ２１の駆動電力の変化について図７を参照して具体的に説明する。図７は、水温低下時の比較処理による第１冷却系２０ａ及び第２冷却系２０ｂにおける電動ファン２３及び電動ウォータポンプ２１の駆動電力の変化と、水温ＴＨＷ１及び水温ＴＨＷ２の変化との関係を示している。尚、図６を参照して説明した水温上昇時の比較処理と同様に、図７に示される時刻ｔ１から時刻ｔ３までの所定期間Ｔｉｎｔが図２及び図３を参照して説明した処理の制御周期に相当する。 Next, changes in driving power of the electric fan 23 and the electric water pump 21 in the comparison process when the water temperature is lowered will be specifically described with reference to FIG. FIG. 7 shows the relationship between changes in the driving power of the electric fan 23 and the electric water pump 21 in the first cooling system 20a and the second cooling system 20b and the changes in the water temperature THW1 and the water temperature THW2 in the comparison process when the water temperature is lowered. ing. In addition, similarly to the comparison process at the time of the water temperature rise described with reference to FIG. 6, the predetermined period Tint from time t1 to time t3 shown in FIG. 7 is controlled by the process described with reference to FIGS. It corresponds to a period.

水温低下時の比較処理が実行されると、図７に示されるように、まず時刻ｔ１において第１冷却系２０ａにおける電動ファン２３ａと第２冷却系２０ｂにおける電動ウォータポンプ２１ｂの駆動電力が所定量αだけ減少される。そして、時刻ｔ２において、図７において実線で示される水温ＴＨＷ１と破線で示される水温ＴＨＷ２とが比較される。ここでは、水温ＴＨＷ１が水温ＴＨＷ２以上である旨判定されるため、第１冷却系２０ａにおける電動ファン２３ａの駆動電力が所定量αだけ増大され、その一方で電動ウォータポンプ２１ａの駆動電力が所定量αだけ減少される。こうして時刻ｔ１における状態に対して第１冷却系２０ａ及び第２冷却系２０ｂにおける電動ウォータポンプ２１の駆動電力がそれぞれ所定量αだけ減少される。こうしてラジエータ２２の放熱量が減少すると機関冷却水温ＴＨＷの低下量は減少する。 When the comparison process when the water temperature is reduced is executed, as shown in FIG. 7, first, at time t1, the driving power of the electric fan 23a in the first cooling system 20a and the electric water pump 21b in the second cooling system 20b is a predetermined amount. It is decreased by α. Then, at time t2, the water temperature THW1 indicated by the solid line in FIG. 7 is compared with the water temperature THW2 indicated by the broken line. Here, since it is determined that the water temperature THW1 is equal to or higher than the water temperature THW2, the driving power of the electric fan 23a in the first cooling system 20a is increased by a predetermined amount α, while the driving power of the electric water pump 21a is predetermined amount. It is decreased by α. Thus, the driving power of the electric water pump 21 in the first cooling system 20a and the second cooling system 20b is decreased by a predetermined amount α with respect to the state at the time t1. Thus, when the heat radiation amount of the radiator 22 is reduced, the reduction amount of the engine coolant temperature THW is reduced.

そして、次の制御周期である時刻ｔ３において、機関冷却水温ＴＨＷが未だ低下中である旨判定されると、再び比較処理が実行され、第１冷却系２０ａにおける電動ファン２３ａと第２冷却系２０ｂにおける電動ウォータポンプ２１ｂの駆動電力が所定量αだけ減少される。時刻ｔ４において、水温ＴＨＷ１と水温ＴＨＷ２とが比較され、水温ＴＨＷ１が水温ＴＨＷ２よりも低い旨判定されると、第２冷却系２０ｂにおける電動ウォータポンプ２１ｂの駆動電力が所定量αだけ増大され、その一方で電動ファン２３ｂの駆動電力が所定量αだけ減少される。こうして時刻ｔ３における状態に対して第１冷却系２０ａ及び第２冷却系２０ｂにおける電動ファン２３の駆動電力が所定量αだけそれぞれ減少される。こうしてラジエータ２２の放熱量が減少すると機関冷却水温ＴＨＷの低下量は更に減少する。時刻ｔ５においても同様に水温低下時の比較処理が実行され、時刻ｔ６において第１冷却系２０ａ及び第２冷却系２０ｂにおける電動ファン２３の駆動電力が所定量αだけ減少される。 When it is determined at time t3 that is the next control cycle that the engine coolant temperature THW is still decreasing, the comparison process is executed again, and the electric fan 23a and the second cooling system 20b in the first cooling system 20a are executed. The driving power of the electric water pump 21b is reduced by a predetermined amount α. At time t4, the water temperature THW1 and the water temperature THW2 are compared, and if it is determined that the water temperature THW1 is lower than the water temperature THW2, the driving power of the electric water pump 21b in the second cooling system 20b is increased by a predetermined amount α, On the other hand, the driving power of the electric fan 23b is reduced by a predetermined amount α. Thus, the driving power of the electric fan 23 in the first cooling system 20a and the second cooling system 20b is decreased by a predetermined amount α with respect to the state at time t3. Thus, when the heat radiation amount of the radiator 22 is reduced, the reduction amount of the engine coolant temperature THW is further reduced. Similarly, at time t5, the comparison process when the water temperature is reduced is executed, and at time t6, the driving power of the electric fan 23 in the first cooling system 20a and the second cooling system 20b is reduced by a predetermined amount α.

機関冷却水温ＴＨＷが比較処理下限水温ＴＨＷｍｉｎ以上であり、且つ機関冷却水温ＴＨＷが低下している場合には、このように電動ファン２３ａと電動ウォータポンプ２１ｂの駆動電力を所定量αだけ減少させる比較処理が所定期間Ｔｉｎｔ毎に繰り返し実行され、その結果に基づいて第１冷却系２０ａ及び第２冷却系２０ｂの電動ファン２３又は電動ウォータポンプのうち単位電力当たりの放熱量の減少量が小さい方の駆動電力が選択的に減少される。こうして、ラジエータ２２の放熱量が徐々に減少され、機関冷却水温ＴＨＷの低下量が減少して機関冷却水温ＴＨＷが所定の温度域に維持されるようになる。 When the engine cooling water temperature THW is equal to or higher than the comparison processing lower limit water temperature THWmin and the engine cooling water temperature THW is lowered, the comparison is made to decrease the drive power of the electric fan 23a and the electric water pump 21b by a predetermined amount α in this way. The process is repeatedly executed every predetermined period Tint, and based on the result, the one with the smaller amount of decrease in the heat dissipation amount per unit power of the electric fan 23 or the electric water pump of the first cooling system 20a and the second cooling system 20b. Drive power is selectively reduced. Thus, the amount of heat released from the radiator 22 is gradually reduced, the amount of decrease in the engine cooling water temperature THW is reduced, and the engine cooling water temperature THW is maintained in a predetermined temperature range.

こうして機関冷却水温ＴＨＷが比較処理下限水温ＴＨＷｍｉｎ以上であり、且つ比較処理上限水温ＴＨＷｍａｘ以下である場合には、電動ファン２３の駆動電力を変更する場合と、電動ウォータポンプ２１の駆動電力を変更する場合との単位電力あたりの放熱量の変化量を比較する比較処理が実行され、この結果に基づいて第１冷却系２０ａ及び第２冷却系２０ｂの双方における電動ファン２３及び電動ウォータポンプ２１のうちいずれか一方の駆動電力が選択的に変更される。 Thus, when the engine cooling water temperature THW is equal to or higher than the comparison processing lower limit water temperature THWmin and equal to or lower than the comparison processing upper limit water temperature THWmax, the driving power of the electric fan 23 is changed and the driving power of the electric water pump 21 is changed. A comparison process for comparing the amount of change in the heat radiation amount per unit power with the case is executed, and based on this result, among the electric fan 23 and the electric water pump 21 in both the first cooling system 20a and the second cooling system 20b Either one of the drive powers is selectively changed.

以上説明した本実施形態によれば、以下の効果が得られるようになる。
（１）機関冷却水の循環経路に並列に配設された第１冷却系２０ａ及び第２冷却系２０ｂにおける還流通路２８に機関冷却水の温度を検出する水温センサ５２がそれぞれ設けられている。そのため、各ラジエータ２２から送出されて他方のラジエータ２２から放出された機関冷却水と合流する前の水温を検出することができる。その結果、他方のラジエータ２２の放熱量が変化することによる影響によって各水温センサ５２により検出される水温ＴＨＷ１，ＴＨＷ２が変化することを抑制することができ、各ラジエータ２２における放熱量の変化量をより正確に推定することができるようになる。そして、第１冷却系２０ａの電動ファン２３ａの駆動電力のみを変化させたときの単位電力当たりの放熱量の変化量と、第２冷却系２０ｂの電動ウォータポンプ２１ｂの駆動電力のみを変化させたときの単位電力当たりの放熱量の変化量を比較する比較処理を実行し、その結果に基づいて冷却系全体の電力消費量が小さくなるように第１冷却系２０ａ及び第２冷却系２０ｂにおける各電動ファン２３及び各電動ウォータポンプ２１の駆動電力を変化させるようにしている。従って、機関冷却水温ＴＨＷ、車両走行風の風量、外気温等、そのときどきの車両運転状態や電動ファン２３及び電動ウォータポンプ２１の各駆動状態により即した態様でラジエータ２２の放熱量を効率的に制御することができ、冷却系全体における電力消費量の増大を抑制しつつ、機関冷却水温ＴＨＷを所定の温度域に維持することができる。 According to the embodiment described above, the following effects can be obtained.
(1) A water temperature sensor 52 for detecting the temperature of the engine cooling water is provided in the recirculation passage 28 in the first cooling system 20a and the second cooling system 20b arranged in parallel with the circulation path of the engine cooling water. Therefore, it is possible to detect the water temperature before merging with the engine cooling water sent from each radiator 22 and released from the other radiator 22. As a result, it is possible to suppress changes in the water temperatures THW1, THW2 detected by the water temperature sensors 52 due to the influence of the change in the heat dissipation amount of the other radiator 22, and the amount of change in the heat dissipation amount in each radiator 22 can be reduced. It becomes possible to estimate more accurately. And only the drive power of the electric water pump 21b of the 2nd cooling system 20b and the variation | change_quantity of the heat dissipation per unit power when changing only the drive power of the electric fan 23a of the 1st cooling system 20a were changed. Comparison processing for comparing the amount of change in the amount of heat dissipation per unit power is performed, and based on the result, each of the first cooling system 20a and the second cooling system 20b is reduced so that the power consumption of the entire cooling system is reduced. The drive power of the electric fan 23 and each electric water pump 21 is changed. Therefore, the amount of heat released from the radiator 22 is efficiently adjusted in a manner that is more appropriate to the state of the vehicle operation and the driving state of the electric fan 23 and the electric water pump 21 such as the engine cooling water temperature THW, the airflow of the vehicle running air, and the outside air temperature. The engine coolant temperature THW can be maintained in a predetermined temperature range while suppressing an increase in power consumption in the entire cooling system.

（２）比較処理に際して電動ファン２３ａの駆動電力と電動ウォータポンプ２１ｂの駆動電力とを同時に変化させるようにしているため、車両運転状態が変動しているような状況にあっても、電動ファン２３ａ、電動ウォータポンプ２１ｂの駆動電力を変化させたときの単位電力当たりの放熱量の各変化量を同じ車両運転状態のもとで推定することができ、比較処理における比較結果の信頼性低下を回避することができる。 (2) Since the driving power of the electric fan 23a and the driving power of the electric water pump 21b are changed at the same time in the comparison process, the electric fan 23a can be used even in a situation where the vehicle operating state fluctuates. The amount of change in heat dissipation per unit power when the drive power of the electric water pump 21b is changed can be estimated under the same vehicle operating condition, and the reliability of the comparison result in the comparison process is prevented from being lowered. can do.

（３）機関冷却水温ＴＨＷが上昇しており、ラジエータ２２の放熱量を増大させて冷却系全体の冷却能力を増大させるときに比較処理を実行し、電動ファン２３及び電動ウォータポンプ２１のうち、単位電力当たりの放熱量の変化量が大きい方の駆動電力を増大させるようにしている。そのため、より少ない消費電力の増大をもって冷却系全体の冷却能力を効率的に増大させることができる。その結果、冷却系全体における電力消費量の増大を抑制しつつ、機関冷却水温を所定の温度域に維持することができるようになる。 (3) When the engine coolant temperature THW is rising and the heat radiation amount of the radiator 22 is increased to increase the cooling capacity of the entire cooling system, the comparison process is executed, and the electric fan 23 and the electric water pump 21 are The drive power with the larger amount of change in the heat dissipation amount per unit power is increased. Therefore, the cooling capacity of the entire cooling system can be efficiently increased with a smaller increase in power consumption. As a result, the engine cooling water temperature can be maintained in a predetermined temperature range while suppressing an increase in power consumption in the entire cooling system.

（４）冷却系全体の冷却能力を増大させるときに、第１冷却系２０ａにおける電動ファン２３ａの駆動電力のみを増大させたときの単位電力当たりの放熱量の増大量と、第２冷却系２０ｂにおける電動ウォータポンプ２１ｂの駆動電力のみを増大させたときの単位電力当たりの放熱量の増大量とを比較する比較処理を実行し、その結果に基づいて電動ファン２３及び電動ウォータポンプ２１のうち単位電力当たりの放熱量の増大量が大きい方の駆動電力を増大させるようにしている。そのため、冷却系全体の冷却能力を増大させるときの電動ファン２３及び電動ウォータポンプ２１の各駆動状態の変化に即した態様で比較処理を実行することができ、冷却系全体の冷却能力をより効率的に増大させることができる。 (4) When increasing the cooling capacity of the entire cooling system, the amount of increase in the amount of heat radiation per unit power when only the driving power of the electric fan 23a in the first cooling system 20a is increased, and the second cooling system 20b A comparison process is performed for comparing the amount of heat dissipation per unit power when only the driving power of the electric water pump 21b is increased, and based on the result, the unit of the electric fan 23 and the electric water pump 21 is compared. The drive power with the larger increase in the amount of heat dissipation per power is increased. Therefore, the comparison process can be executed in a manner in accordance with changes in the driving states of the electric fan 23 and the electric water pump 21 when the cooling capacity of the entire cooling system is increased, and the cooling capacity of the entire cooling system is made more efficient. Can be increased.

（５）機関冷却水温ＴＨＷが低下しており、ラジエータ２２の放熱量を減少させて冷却系全体の冷却能力を低下させるときに比較処理を実行し、電動ファン２３及び電動ウォータポンプ２１のうち、単位電力当たりの放熱量の変化量が小さい方の駆動電力を減少させるようにしている。そのため、冷却系全体の冷却能力を所定量だけ減少させるのに際し、冷却系全体における駆動電力をより大きく減少させることができる。その結果、冷却系全体における電力消費量の増大を抑制しつつ、機関冷却水温を所定の温度域に維持することができるようになる。 (5) When the engine coolant temperature THW is lowered and the amount of heat released from the radiator 22 is reduced to reduce the cooling capacity of the entire cooling system, the comparison process is executed, and among the electric fan 23 and the electric water pump 21, The drive power with the smaller change amount of the heat dissipation per unit power is reduced. Therefore, when reducing the cooling capacity of the entire cooling system by a predetermined amount, the driving power in the entire cooling system can be greatly reduced. As a result, the engine cooling water temperature can be maintained in a predetermined temperature range while suppressing an increase in power consumption in the entire cooling system.

（６）冷却系全体の冷却能力を低下させるときに、第１冷却系２０ａの電動ファン２３ａの駆動電力のみを減少させたときの単位電力当たりの放熱量の減少量と、第２冷却系２０ｂの電動ウォータポンプ２１ｂの駆動電力のみを減少させたときの単位電力当たりの放熱量の減少量とを比較する比較処理を実行し、その結果に基づいて、電動ファン２３及び電動ウォータポンプ２１のうち単位電力当たりの放熱量の減少量が小さい方の駆動電力を減少させるようにしている。そのため、冷却系全体の冷却能力を低下させるときの電動ファン２３及び電動ウォータポンプ２１の各駆動状態の変化に即した態様で比較処理を実行することができるようになり、冷却系全体の冷却能力をより効率的に減少させることができるようになる。 (6) When the cooling capacity of the entire cooling system is reduced, the amount of decrease in the heat radiation amount per unit power when only the drive power of the electric fan 23a of the first cooling system 20a is reduced, and the second cooling system 20b Of the electric water pump 21b is compared with the amount of decrease in the amount of heat released per unit power when the electric water pump 21b is reduced. Based on the result, the electric fan 23 and the electric water pump 21 The drive power with the smaller amount of reduction in heat dissipation per unit power is reduced. Therefore, the comparison process can be executed in a manner in accordance with changes in the driving states of the electric fan 23 and the electric water pump 21 when the cooling capacity of the entire cooling system is reduced, and the cooling capacity of the entire cooling system Can be reduced more efficiently.

尚、上記実施形態は、これを適宜変更した以下の形態にて実施することもできる。
・上記実施形態では、機関冷却水温ＴＨＷが上昇しており、ラジエータ２２の放熱量を増大させて冷却系全体の冷却能力を増大させる場合に、第１冷却系２０ａにおける電動ファン２３ａと第２冷却系２０ｂにおける電動ウォータポンプ２１ｂの駆動電力を増大させて放熱量の変化量を比較する水温上昇時の比較処理を実行する構成を示した。これに対して、この発明はこうした構成に限定されるものではなく、第１冷却系２０ａにおける電動ファン２３ａと、第２冷却系２０ｂにおける電動ウォータポンプ２１ｂとの駆動電力をそれぞれ所定量αだけ変化させ、その後に検出される水温ＴＨＷ１及びＴＨＷ２に基づいて放熱量の変化量を比較することができる構成であればよい。例えば、電動ファン２３ａ及び電動ウォータポンプ２１ｂの駆動電力を所定量αだけ減少させたときの放熱量の低下量を比較し、それぞれの低下量を比較した結果に基づいて電動ファン２３、電動ウォータポンプ２１の駆動電力を増大させる構成を採用することもできる。 In addition, the said embodiment can also be implemented with the following forms which changed this suitably.
In the above embodiment, when the engine cooling water temperature THW has risen and the heat radiation amount of the radiator 22 is increased to increase the cooling capacity of the entire cooling system, the electric fan 23a and the second cooling in the first cooling system 20a The structure which performs the comparison process at the time of the water temperature rise which increases the drive electric power of the electric water pump 21b in the system 20b, and compares the variation | change_quantity of thermal radiation amount was shown. In contrast, the present invention is not limited to such a configuration, and the driving power of the electric fan 23a in the first cooling system 20a and the electric water pump 21b in the second cooling system 20b is changed by a predetermined amount α, respectively. The amount of change in the amount of heat release may be compared based on the water temperatures THW1 and THW2 detected thereafter. For example, when the driving power of the electric fan 23a and the electric water pump 21b is reduced by a predetermined amount α, the amount of decrease in the heat radiation amount is compared, and the electric fan 23 and the electric water pump are compared based on the result of comparing the respective reduction amounts. It is also possible to adopt a configuration in which the drive power of 21 is increased.

・また同様に、機関冷却水温ＴＨＷが低下しており、ラジエータ２２の放熱量を減少させて冷却系全体の冷却能力を低下させる場合に、第１冷却系２０ａにおける電動ファン２３ａと第２冷却系２０ｂにおける電動ウォータポンプ２１ｂの駆動電力を減少させて放熱量の変化量を比較する水温低下時の比較処理を実行する構成を示したが、この発明は、こうした構成に限定されるものではない。即ち、第１冷却系２０ａにおける電動ファン２３ａと、第２冷却系２０ｂにおける電動ウォータポンプ２１ｂとの駆動電力をそれぞれ所定量αだけ変化させ、その後に検出される水温ＴＨＷ１及び水温ＴＨＷ２に基づいて放熱量の変化量を比較することができる構成であればよい。例えば、電動ファン２３ａ及び電動ウォータポンプ２１ｂの駆動電力を所定量αだけ増大させたときの放熱量の増大量を比較し、それぞれの増大量を比較した結果に基づいて電動ファン２３、電動ウォータポンプ２１の駆動電力を減少させる構成を採用することもできる。 Similarly, when the engine cooling water temperature THW is lowered and the cooling capacity of the entire cooling system is lowered by reducing the heat radiation amount of the radiator 22, the electric fan 23a and the second cooling system in the first cooling system 20a Although the configuration has been shown in which the comparison processing at the time of the water temperature decrease is performed in which the driving power of the electric water pump 21b in 20b is reduced to compare the amount of change in the heat dissipation amount, the present invention is not limited to such a configuration. That is, the driving power of the electric fan 23a in the first cooling system 20a and the electric water pump 21b in the second cooling system 20b are changed by a predetermined amount α, respectively, and then released based on the detected water temperature THW1 and water temperature THW2. Any configuration that can compare the amount of change in the amount of heat is acceptable. For example, when the driving power of the electric fan 23a and the electric water pump 21b is increased by a predetermined amount α, the amount of increase in heat dissipation is compared, and the electric fan 23 and the electric water pump are compared based on the results of comparing the respective increases. It is also possible to employ a configuration in which the drive power of 21 is reduced.

・また、上記実施形態では、第１冷却系２０ａにおける電動ファン２３ａと、第２冷却系２０ｂにおける電動ウォータポンプ２１ｂの駆動電力をそれぞれ所定量αだけ変化させる比較処理を実行し、その結果に基づいて第１冷却系２０ａ及び第２冷却系２０ｂの双方における電動ファン２３及び電動ウォータポンプ２１のうち一方の駆動電力を所定量αだけ変化させる構成を示した。これに対して、比較処理の際の駆動電力の変更量と、その結果に基づいて電動ファン２３又は電動ウォータポンプ２１の駆動電力を変化させる際の変更量とは異なっていてもよい。但し、これら変更量の差が大きいと、各冷却系２０ａ，２０ｂの比較処理実行時の状態と実際に電動ファン２３又は電動ウォータポンプ２１の駆動電力を変化させたときの状態とが大きく異なることとなり、比較処理の精度が低下することとなる。このため、比較処理の際の駆動電力の変更量と、その結果に基づいて電動ファン２３又は電動ウォータポンプ２１の駆動電力を変化させる際の変更量との差は所定量以下に設定するのが望ましい。 -Moreover, in the said embodiment, the comparison process which changes the drive electric power of the electric fan 23a in the 1st cooling system 20a and the electric water pump 21b in the 2nd cooling system 20b by each predetermined amount (alpha) is performed, and based on the result Thus, the configuration is shown in which the drive power of one of the electric fan 23 and the electric water pump 21 in both the first cooling system 20a and the second cooling system 20b is changed by a predetermined amount α. On the other hand, the amount of change in the driving power during the comparison process may be different from the amount of change in changing the driving power of the electric fan 23 or the electric water pump 21 based on the result. However, if the difference between these change amounts is large, the state when the comparison processing of the cooling systems 20a and 20b is executed and the state when the driving power of the electric fan 23 or the electric water pump 21 is actually changed greatly differ. Thus, the accuracy of the comparison process is reduced. For this reason, the difference between the amount of change in driving power during the comparison process and the amount of change in changing the driving power of the electric fan 23 or the electric water pump 21 based on the result is set to a predetermined amount or less. desirable.

・また、駆動電力の変更量が上記実施形態のように常に一定に設定されている構成の他、機関冷却水温ＴＨＷの変化度合に応じて駆動電力の変更量を可変設定する構成を採用することもできる。例えば、機関冷却水温ＴＨＷの変化量が大きいときには、駆動電力の変更量を大きくするといった構成を採用することもできる。 In addition to the configuration in which the change amount of the drive power is always set to be constant as in the above embodiment, a configuration in which the change amount of the drive power is variably set according to the change degree of the engine coolant temperature THW is adopted. You can also. For example, when the change amount of the engine coolant temperature THW is large, a configuration in which the change amount of the drive power is increased can be employed.

・また、比較処理の結果に基づいて電動ファン２３の駆動電力を増大させる場合には、上記実施形態のように電動ファン２３の駆動電力のみを増大させる構成の他、電動ファン２３及び電動ウォータポンプ２１の駆動電力の双方を増大させる際に、その電動ファン２３に関する増大量を電動ウォータポンプ２１に関する増大量よりも大きく設定する構成を採用することもできる。また同様に、比較処理の結果に基づいて電動ウォータポンプ２１の駆動電力を増大させる場合には、電動ウォータポンプ２１の駆動電力のみを増大させる構成の他、電動ファン２３及び電動ウォータポンプ２１の駆動電力の双方を増大させる際に、その電動ウォータポンプ２１に関する増大量を電動ファン２３に関する増大量よりも大きく設定する構成を採用することもできる。この点は、比較処理の結果に基づいて電動ファン２３の駆動電力を減少させる場合、及び電動ウォータポンプ２１の駆動電力を減少させる場合についても同様である。 In addition, when the driving power of the electric fan 23 is increased based on the result of the comparison process, the electric fan 23 and the electric water pump are configured in addition to the configuration in which only the driving power of the electric fan 23 is increased as in the above embodiment. It is also possible to employ a configuration in which the amount of increase related to the electric fan 23 is set larger than the amount of increase related to the electric water pump 21 when both of the drive power of 21 are increased. Similarly, when the drive power of the electric water pump 21 is increased based on the result of the comparison process, in addition to the configuration in which only the drive power of the electric water pump 21 is increased, the drive of the electric fan 23 and the electric water pump 21 is increased. It is also possible to employ a configuration in which the amount of increase related to the electric water pump 21 is set larger than the amount of increase related to the electric fan 23 when both the electric powers are increased. The same applies to the case where the driving power of the electric fan 23 is reduced based on the result of the comparison process and the case where the driving power of the electric water pump 21 is reduced.

・また、上記実施形態では、比較処理下限水温ＴＨＷｍｉｎとして機関運転に適した機関冷却水温の下限値が設定され、比較処理上限水温ＴＨＷｍａｘとして機関運転に適した機関冷却水温の上限値が設定されている。そして、機関冷却水温ＴＨＷが比較処理下限水温ＴＨＷｍｉｎ以上、且つ比較処理上限水温ＴＨＷｍａｘ以下であるときに、比較処理を実行して電動ファン２３及び電動ウォータポンプ２１の駆動電力を制御する構成を示した。これに対して、比較処理下限水温ＴＨＷｍｉｎ及び比較処理上限水温ＴＨＷｍａｘは、こうした値に限定されるものではなく適宜変更して設定することができる。また、こうした比較処理下限水温ＴＨＷｍｉｎ及び比較処理上限水温ＴＨＷｍａｘを設定せずに常に比較処理を実行して駆動電力を制御する構成や、比較処理下限水温ＴＨＷｍｉｎ又は比較処理上限水温ＴＨＷｍａｘの一方のみを設定する構成を採用してもよい。 In the above embodiment, the lower limit value of the engine cooling water temperature suitable for engine operation is set as the comparison processing lower limit water temperature THWmin, and the upper limit value of the engine cooling water temperature suitable for engine operation is set as the comparison processing upper limit water temperature THWmax. Yes. Then, when the engine cooling water temperature THW is equal to or higher than the comparison processing lower limit water temperature THWmin and equal to or lower than the comparison processing upper limit water temperature THWmax, the comparison processing is executed to control the driving power of the electric fan 23 and the electric water pump 21. . On the other hand, the comparison process lower limit water temperature THWmin and the comparison process upper limit water temperature THWmax are not limited to these values and can be appropriately changed and set. In addition, a configuration in which the comparison process is always executed without setting the comparison process lower limit water temperature THWmin and the comparison process upper limit water temperature THWmax, and only one of the comparison process lower limit water temperature THWmin or the comparison process upper limit water temperature THWmax is set. You may employ | adopt the structure to do.

・また、機関冷却水温ＴＨＷが上昇しているときにのみ、又は機関冷却水温ＴＨＷが低下しているときにのみ比較処理を実行する構成を採用することもできる。
・上記実施形態では、比較処理に際して第１冷却系２０ａにおける電動ファン２３ａと、第２冷却系２０ｂにおける電動ウォータポンプ２１ｂの駆動電力を同時に変化させる構成を示したが、第１冷却系２０ａにおける電動ファン２３ａと第２冷却系２０ｂにおける電動ウォータポンプ２１ｂの駆動電力を変化させる時期は必ずしも同時でなくてもよい。但し、このようにした場合であっても、比較処理の精度を高める上では、第１冷却系２０ａにおける電動ファン２３ａの駆動電力を変化させる時期と第２冷却系２０ｂにおける電動ウォータポンプ２１ｂの駆動電力を変化させる時期との時間間隔を極力短く設定することが望ましい。 Further, it is possible to adopt a configuration in which the comparison process is executed only when the engine coolant temperature THW is rising or only when the engine coolant temperature THW is decreasing.
In the above embodiment, the configuration in which the driving power of the electric fan 23a in the first cooling system 20a and the electric water pump 21b in the second cooling system 20b are simultaneously changed during the comparison process is shown. The timing for changing the driving power of the electric water pump 21b in the fan 23a and the second cooling system 20b is not necessarily the same. However, even in this case, in order to increase the accuracy of the comparison process, the timing for changing the driving power of the electric fan 23a in the first cooling system 20a and the driving of the electric water pump 21b in the second cooling system 20b are used. It is desirable to set the time interval with the time to change the power as short as possible.

・上記実施形態では、並列に配設された第１冷却系２０ａと第２冷却系２０ｂとを備え、比較処理に際して、第１冷却系２０ａにおける電動ファン２３ａと、第２冷却系２０ｂにおける電動ウォータポンプ２１ｂの駆動電力を変化させる構成を示したが、この発明はこのように並列に配設された一対の冷却系を有する冷却装置に限定されるものではない。即ち、電動ウォータポンプと電動ファンとを備え、それぞれの駆動電力を変更することによりラジエータの放熱量を変化させることのできる冷却装置であれば、比較処理を実行することができる。こうした構成を採用する場合には、まず電動ファン及び電動ウォータポンプうち一方の駆動電力のみを変化させたときの放熱量の変化量を推定したあと、駆動電力を元の状態に戻して機関冷却水温を安定させ、機関冷却水温が安定した状態で他方の駆動電力のみを変化させて放熱量の変化量を推定するといった構成を採用することにより、放熱量の変化量を比較することができる。 In the above embodiment, the first cooling system 20a and the second cooling system 20b arranged in parallel are provided, and the electric fan 23a in the first cooling system 20a and the electric water in the second cooling system 20b are provided for the comparison process. Although the configuration in which the driving power of the pump 21b is changed is shown, the present invention is not limited to the cooling device having a pair of cooling systems arranged in parallel as described above. In other words, the comparison process can be executed as long as the cooling device includes an electric water pump and an electric fan and can change the heat radiation amount of the radiator by changing the driving power. When such a configuration is adopted, first, after estimating the amount of change in heat dissipation when only the driving power of one of the electric fan and electric water pump is changed, the driving power is returned to the original state and the engine cooling water temperature is changed. The amount of change in heat release can be compared by adopting a configuration in which the amount of change in heat release is estimated by changing only the other drive power while the engine cooling water temperature is stable.

・また、こうした構成を採用する場合にあっても、比較処理の結果に基づいて電動ファンの駆動電力を増大させる場合には、電動ファンの駆動電力のみを増大させる構成の他、電動ファン及び電動ウォータポンプの駆動電力の双方を増大させる際に、その電動ファンに関する増大量を電動ウォータポンプに関する増大量よりも大きく設定する構成を採用することができる。また同様に、比較処理の結果に基づいて電動ウォータポンプの駆動電力を増大させる場合には、電動ウォータポンプの駆動電力のみを増大させる構成の他、電動ファン及び電動ウォータポンプの駆動電力の双方を増大させる際に、その電動ウォータポンプに関する増大量を電動ファンに関する増大量よりも大きく設定する構成を採用することもできる。この点は、比較処理の結果に基づいて電動ファンの駆動電力を減少させる場合、電動ウォータポンプの駆動電力を減少させる場合についても同様である。 Even when such a configuration is adopted, in the case where the driving power of the electric fan is increased based on the result of the comparison process, in addition to the configuration in which only the driving power of the electric fan is increased, the electric fan and the electric motor When increasing both of the drive power of the water pump, it is possible to employ a configuration in which the increase amount related to the electric fan is set larger than the increase amount related to the electric water pump. Similarly, in the case of increasing the driving power of the electric water pump based on the result of the comparison process, in addition to the configuration in which only the driving power of the electric water pump is increased, both the driving power of the electric fan and the electric water pump are When increasing, the structure which sets the increase amount regarding the electric water pump larger than the increase amount regarding the electric fan can also be employ | adopted. The same applies to the case where the drive power of the electric fan is reduced based on the result of the comparison process and the case where the drive power of the electric water pump is reduced.

この発明の一実施形態にかかる冷却装置の概略構成を示す模式図。The schematic diagram which shows schematic structure of the cooling device concerning one Embodiment of this invention. 同実施形態にかかる冷却装置の駆動電力制御の流れを示すフローチャート。The flowchart which shows the flow of the drive electric power control of the cooling device concerning the embodiment. 同実施形態にかかる冷却装置の駆動電力制御の流れを示すフローチャート。The flowchart which shows the flow of the drive electric power control of the cooling device concerning the embodiment. 機関冷却水温及び機関負荷と電動ウォータポンプの駆動電力の関係を示すグラフ。The graph which shows the relationship between engine cooling water temperature and engine load, and the drive power of an electric water pump. 機関冷却水温の変化と電動ファン及び電動ウォータポンプの駆動電力の制御態様との関係を示すタイムチャート。The time chart which shows the relationship between the change of engine cooling water temperature, and the control aspect of the drive electric power of an electric fan and an electric water pump. 水温上昇時の比較処理における電動ファン及び電動ウォータポンプの駆動電力の変化と水温の変化との関係を示すタイムチャート。The time chart which shows the relationship between the change of the drive electric power of an electric fan and an electric water pump, and the change of water temperature in the comparison process at the time of water temperature rise. 水温低下時の比較処理における電動ファン及び電動ウォータポンプの駆動電力の変化と水温の変化との関係を示すタイムチャート。The time chart which shows the relationship between the change of the drive electric power of an electric fan and an electric water pump, and the change of water temperature in the comparison process at the time of water temperature fall.

符号の説明Explanation of symbols

１０…内燃機関、１２…ウォータジャケット、２０ａ…第１冷却系、２０ｂ…第２冷却系、２１…電動ウォータポンプ、２２…ラジエータ、２３…電動ファン、２４…吐出通路、２５…供給通路、２６…導入通路、２７…バイパス通路、２８…還流通路、２９…吸入通路、３０…サーモスタットバルブ、５０…電子制御装置、５１…機関水温センサ、５２…水温センサ、５３…回転速度センサ、５４…エアフロメータ。 DESCRIPTION OF SYMBOLS 10 ... Internal combustion engine, 12 ... Water jacket, 20a ... 1st cooling system, 20b ... 2nd cooling system, 21 ... Electric water pump, 22 ... Radiator, 23 ... Electric fan, 24 ... Discharge passage, 25 ... Supply passage, 26 DESCRIPTION OF SYMBOLS ... Introduction passage, 27 ... Bypass passage, 28 ... Recirculation passage, 29 ... Intake passage, 30 ... Thermostat valve, 50 ... Electronic control device, 51 ... Engine water temperature sensor, 52 ... Water temperature sensor, 53 ... Rotation speed sensor, 54 ... Air flow Meter.

Claims

電動ウォータポンプにより内燃機関とラジエータとの間で機関冷却水を循環させるとともに電動ファンの冷却風により前記ラジエータ内の機関冷却水を冷却する冷却系と、機関冷却水温が所定の温度域に維持されるように前記冷却系の電動ファン及び電動ウォータポンプの駆動電力を制御する制御手段とを有する車載内燃機関の冷却装置において、
前記ラジエータの放熱量の変化量を機関冷却水温に基づいて推定する放熱量推定手段を備え、
前記制御手段は前記電動ファンの駆動電力のみを変化させたときの単位電力当たりの放熱量の変化量と、前記電動ウォータポンプの駆動電力のみを変化させたときの単位電力当たりの放熱量の変化量とを比較する比較処理を実行し、同比較処理の結果に基づき、前記冷却系全体の電力消費量が小さくなるように前記電動ファン及び前記電動ウォータポンプの駆動電力を制御する
ことを特徴とする車載内燃機関の冷却装置。 A cooling system for circulating the engine cooling water between the internal combustion engine and the radiator by the electric water pump and cooling the engine cooling water in the radiator by the cooling air of the electric fan, and the engine cooling water temperature are maintained in a predetermined temperature range. In the cooling system for an on-vehicle internal combustion engine having control means for controlling the driving power of the electric fan and the electric water pump of the cooling system,
A heat radiation amount estimating means for estimating the amount of change in the heat radiation amount of the radiator based on the engine coolant temperature;
The control means changes the amount of heat released per unit power when only the driving power of the electric fan is changed, and changes in the amount of heat released per unit power when only the driving power of the electric water pump is changed. A comparison process is performed to compare the amount of the electric fan, and based on the result of the comparison process, the drive power of the electric fan and the electric water pump is controlled so that the power consumption of the entire cooling system is reduced. A cooling device for an on-vehicle internal combustion engine.

請求項１に記載の車載内燃機関の冷却装置において、
前記制御手段は前記ラジエータの放熱量を増大させるときに前記比較処理を実行し、前記電動ファンの駆動電力のみを変化させたときの単位電力当たりの放熱量の変化量が前記電動ウォータポンプの駆動電力のみを変化させたときの単位電力当たりの放熱量の変化量よりも大きい場合には前記電動ファンの駆動電力を増大させる一方、前記電動ファンの駆動電力のみを変化させたときの単位電力当たりの放熱量の変化量が前記電動ウォータポンプの駆動電力のみを変化させたときの単位電力当たりの放熱量の変化量よりも小さい場合には前記電動ウォータポンプの駆動電力を増大させる
ことを特徴とする車載内燃機関の冷却装置。 The cooling device for an on-vehicle internal combustion engine according to claim 1,
The control means performs the comparison process when increasing the heat dissipation amount of the radiator, and the amount of change in the heat dissipation amount per unit power when only the drive power of the electric fan is changed is the driving of the electric water pump. If the amount of heat dissipation per unit power is larger than the amount of change in heat dissipation when only the power is changed, the driving power of the electric fan is increased, while the unit power per unit power when only the driving power of the electric fan is changed. When the amount of change in the heat dissipation amount is smaller than the amount of change in the heat dissipation amount per unit power when only the drive power of the electric water pump is changed, the drive power of the electric water pump is increased. A cooling device for an on-vehicle internal combustion engine.

請求項２に記載の車載内燃機関の冷却装置において、
前記制御手段は前記電動ファンの駆動電力のみを増大させたときの単位電力当たりの放熱量の増大量が前記電動ウォータポンプの駆動電力のみを増大させたときの単位電力当たりの放熱量の増大量よりも大きい場合には前記電動ファンの駆動電力を増大させる一方、前記電動ファンの駆動電力のみを増大させたときの単位電力当たりの放熱量の増大量が前記電動ウォータポンプの駆動電力のみを増大させたときの単位電力当たりの放熱量の増大量よりも小さい場合には前記電動ウォータポンプの駆動電力を増大させる
ことを特徴とする車載内燃機関の冷却装置。 The cooling device for an on-vehicle internal combustion engine according to claim 2,
The control means increases the amount of heat dissipation per unit power when the amount of increase in heat dissipation per unit power when only the drive power of the electric fan is increased increases only the drive power of the electric water pump. Is larger than the driving power of the electric fan, the increase in the amount of heat dissipation per unit power when only the driving power of the electric fan is increased increases only the driving power of the electric water pump. A cooling apparatus for an on-vehicle internal combustion engine, wherein the driving power of the electric water pump is increased when the amount of heat radiation per unit electric power is smaller than the increase in heat dissipation.

請求項１に記載の車載内燃機関の冷却装置において、
前記制御手段は前記ラジエータの放熱量を減少させるときに前記比較処理を実行し、前記電動ファンの駆動電力のみを変化させたときの単位電力当たりの放熱量の変化量が前記電動ウォータポンプの駆動電力のみを変化させたときの単位電力当たりの放熱量の変化量よりも小さい場合には前記電動ファンの駆動電力を減少させる一方、前記電動ファンの駆動電力のみを変化させたときの単位電力当たりの放熱量の変化量が前記電動ウォータポンプの駆動電力のみを変化させたときの単位電力当たりの放熱量の変化量よりも大きい場合には前記電動ウォータポンプの駆動電力を減少させる
ことを特徴とする車載内燃機関の冷却装置。 The cooling device for an on-vehicle internal combustion engine according to claim 1,
The control means executes the comparison process when reducing the heat dissipation amount of the radiator, and the amount of change in the heat dissipation amount per unit power when only the drive power of the electric fan is changed is the drive of the electric water pump. When it is smaller than the amount of change in heat dissipation per unit power when only the power is changed, the driving power of the electric fan is reduced, while per unit power when only the driving power of the electric fan is changed. When the amount of change in the amount of heat released is greater than the amount of change in the amount of heat released per unit power when only the drive power of the electric water pump is changed, the drive power of the electric water pump is reduced. A cooling device for an on-vehicle internal combustion engine.

請求項４に記載の車載内燃機関の冷却装置において、
前記制御手段は前記電動ファンの駆動電力のみを減少させたときの単位電力当たりの放熱量の減少量が前記電動ウォータポンプの駆動電力のみを減少させたときの単位電力当たりの放熱量の減少量よりも小さい場合には前記電動ファンの駆動電力を減少させる一方、前記電動ファンの駆動電力のみを減少させたときの単位電力当たりの放熱量の減少量が前記電動ウォータポンプの駆動電力のみを減少させたときの単位電力当たりの放熱量の減少量よりも大きい場合には前記電動ウォータポンプの駆動電力を減少させる
ことを特徴とする車載内燃機関の冷却装置。 The cooling device for an on-vehicle internal combustion engine according to claim 4,
The control means reduces the amount of heat dissipation per unit power when the amount of decrease in heat dissipation per unit power when only the drive power of the electric fan is reduced decreases the drive power of the electric water pump. Is smaller than the driving power of the electric fan, the decrease in the amount of heat dissipation per unit power when only the driving power of the electric fan is decreased reduces only the driving power of the electric water pump. A cooling device for an on-vehicle internal combustion engine, wherein the driving power of the electric water pump is reduced when the amount of heat dissipation per unit power is larger than the amount of reduction in heat dissipation.

請求項１〜５のいずれか一項に記載の車載内燃機関の冷却装置において、
放熱量推定手段は前記ラジエータから送出されて前記内燃機関に流入する前の機関冷却水の温度を検出する水温検出手段を備え、同水温検出手段によって検出された機関冷却水温に基づいて前記ラジエータの放熱量の変化量を推定する
ことを特徴とする車載内燃機関の冷却装置。 In the cooling device for a vehicle-mounted internal combustion engine according to any one of claims 1 to 5,
The heat radiation amount estimating means includes a water temperature detecting means for detecting the temperature of the engine cooling water sent from the radiator and flowing into the internal combustion engine, and based on the engine cooling water temperature detected by the water temperature detecting means, A cooling device for an on-vehicle internal combustion engine, characterized in that the amount of change in heat radiation is estimated.

電動ウォータポンプにより内燃機関とラジエータとの間で機関冷却水を循環させるとともに電動ファンの冷却風によりラジエータ内の機関冷却水を冷却する一対の冷却系が機関冷却水の循環経路に並列に配設され、機関冷却水温が所定の温度域に維持されるように前記一対の冷却系の各電動ファン及び各電動ウォータポンプの駆動電力を制御する制御手段を有する車載内燃機関の冷却装置において、
前記一対の冷却系の各ラジエータから送出されて他方のラジエータから放出された機関冷却水温と合流する前の機関冷却水温をそれぞれ検出する一対の水温検出手段を有し、同水温検出手段によって検出される機関冷却水温に基づいて各ラジエータの放熱量を各別に推定する放熱量推定手段を備え、
前記制御手段は前記一対の冷却系のうち一方の冷却系における電動ファンの駆動電力のみを変化させたときの単位電力当たりの放熱量の変化量と、他方の冷却系における電動ウォータポンプの駆動電力のみを変化させたときの単位電力当たりの放熱量の変化量とを比較する比較処理を実行し、同比較処理の結果に基づき、前記冷却系全体の電力消費量が小さくなるように前記一対の冷却系の各電動ファン及び各電動ウォータポンプの駆動電力を制御する
ことを特徴とする車載内燃機関の冷却装置。 A pair of cooling systems that circulate the engine cooling water between the internal combustion engine and the radiator by the electric water pump and cool the engine cooling water in the radiator by the cooling air of the electric fan are arranged in parallel to the circulation path of the engine cooling water. And a cooling device for an on-vehicle internal combustion engine having control means for controlling the driving power of each electric fan and each electric water pump of the pair of cooling systems so that the engine cooling water temperature is maintained in a predetermined temperature range.
It has a pair of water temperature detecting means for detecting the engine cooling water temperature before joining the engine cooling water temperature sent from each radiator of the pair of cooling systems and discharged from the other radiator, and is detected by the water temperature detecting means. Heat radiation amount estimating means for estimating the heat radiation amount of each radiator based on the engine coolant temperature
The control means changes the amount of heat radiation per unit power when only the driving power of the electric fan in one cooling system of the pair of cooling systems is changed, and the driving power of the electric water pump in the other cooling system. A comparison process is performed to compare the amount of change in the heat dissipation amount per unit power when only the change is made, and based on the result of the comparison process, the pair of the pair of cooling systems is configured so that the power consumption of the entire cooling system is reduced. A cooling system for an on-vehicle internal combustion engine, wherein driving electric power of each electric fan and each electric water pump of the cooling system is controlled.

請求項７に記載の車載内燃機関の冷却装置において、
前記制御手段は前記比較処理に際して前記一対の冷却系のうち一方の冷却系における電動ファンの駆動電力と、他方の冷却系における電動ウォータポンプの駆動電力とを同時に変化させる
ことを特徴とする車載内燃機関の冷却装置。 The cooling device for an on-vehicle internal combustion engine according to claim 7,
The control means simultaneously changes the driving power of the electric fan in one cooling system of the pair of cooling systems and the driving power of the electric water pump in the other cooling system during the comparison process. Engine cooling system.

請求項７又は請求項８に記載の車載内燃機関の冷却装置において、
前記制御手段は各ラジエータの放熱量を増大させて前記冷却系全体の冷却能力を増大させるときに前記比較処理を実行し、前記一方の冷却系における電動ファンの駆動電力のみを変化させたときの単位電力当たりの放熱量の変化量が前記他方の冷却系における電動ウォータポンプの駆動電力のみを変化させたときの単位電力当たりの放熱量の変化量よりも大きい場合には前記一対の冷却系における各電動ファンの駆動電力をそれぞれ増大させる一方、前記一方の冷却系における電動ファンの駆動電力のみを変化させたときの単位電力当たりの放熱量の変化量が前記他方の冷却系における電動ウォータポンプの駆動電力のみを変化させたときの単位電力当たりの放熱量の変化量よりも小さい場合には前記一対の冷却系における各電動ウォータポンプの駆動電力をそれぞれ増大させる
ことを特徴とする車載内燃機関の冷却装置。 In the cooling device for an on-vehicle internal combustion engine according to claim 7 or 8,
The control means executes the comparison process when increasing the heat radiation amount of each radiator to increase the cooling capacity of the entire cooling system, and changes only the driving power of the electric fan in the one cooling system. When the amount of change in the heat dissipation amount per unit power is larger than the amount of change in the heat dissipation amount per unit power when only the driving power of the electric water pump in the other cooling system is changed, in the pair of cooling systems While the drive power of each electric fan is increased, the amount of change in the heat dissipation per unit power when only the drive power of the electric fan in the one cooling system is changed is the amount of change in the electric water pump in the other cooling system. If the amount of heat radiation per unit power is smaller than when only the driving power is changed, each electric water poWer in the pair of cooling systems Cooling apparatus for an internal combustion engine which comprises bringing the drive power of up to increase respectively.

請求項９に記載の車載内燃機関の冷却装置において、
前記制御手段は前記一方の冷却系における電動ファンの駆動電力のみを増大させたときの単位電力当たりの放熱量の増大量が前記他方の冷却系における電動ウォータポンプの駆動電力のみを増大させたときの単位電力当たりの放熱量の増大量よりも大きい場合には前記一対の冷却系の電動ファンの駆動電力を増大させる一方、前記一方の冷却系における電動ファンの駆動電力のみを増大させたときの単位電力当たりの放熱量の増大量が前記他方の冷却系における電動ウォータポンプの駆動電力のみを増大させたときの単位電力当たりの放熱量の増大量よりも小さい場合には前記一対の冷却系の電動ウォータポンプの駆動電力を増大させる
ことを特徴とする車載内燃機関の冷却装置。 The cooling device for an on-vehicle internal combustion engine according to claim 9,
When the control means increases only the driving power of the electric water pump in the other cooling system when the increase amount of the heat dissipation per unit power when only the driving power of the electric fan in the one cooling system is increased When the heat dissipation amount per unit power is larger than the increase amount of the heat dissipation amount per unit power, the drive power of the pair of cooling system electric fans is increased, while only the drive power of the electric fan in the one cooling system is increased. If the increase in the heat dissipation amount per unit power is smaller than the increase in the heat dissipation amount per unit power when only the driving power of the electric water pump in the other cooling system is increased, the pair of cooling systems A cooling device for an on-vehicle internal combustion engine, characterized in that the driving power of an electric water pump is increased.

請求項７又は請求項８に記載の車載内燃機関の冷却装置において、
前記制御手段は各ラジエータの放熱量を減少させて前記冷却系全体の冷却能力を低下させるときに前記比較処理を実行し、前記一方の冷却系における電動ファンの駆動電力のみを変化させたときの単位電力当たりの放熱量の変化量が前記他方の冷却系における電動ウォータポンプの駆動電力のみを変化させたときの単位電力当たりの放熱量の変化量よりも小さい場合には前記一対の冷却系の電動ファンの駆動電力を減少させる一方、前記一方の冷却系における電動ファンの駆動電力のみを変化させたときの単位電力当たりの放熱量の変化量が前記他方の冷却系における電動ウォータポンプの駆動電力のみを変化させたときの単位電力当たりの放熱量の変化量よりも大きい場合には前記一対の冷却系の電動ウォータポンプの駆動電力を減少させる
ことを特徴とする車載内燃機関の冷却装置。 In the cooling device for an on-vehicle internal combustion engine according to claim 7 or 8,
The control means executes the comparison process when the heat radiation amount of each radiator is decreased to reduce the cooling capacity of the entire cooling system, and only the driving power of the electric fan in the one cooling system is changed. When the amount of change in the heat dissipation amount per unit power is smaller than the amount of change in the heat dissipation amount per unit power when only the driving power of the electric water pump in the other cooling system is changed, the pair of cooling systems While the drive power of the electric fan is reduced, the amount of change in the heat dissipation per unit power when only the drive power of the electric fan in the one cooling system is changed is the drive power of the electric water pump in the other cooling system If it is larger than the amount of change in the heat dissipation per unit power when only the change is made, the drive power of the electric water pump of the pair of cooling systems is reduced. Cooling apparatus for an internal combustion engine, characterized in that.

請求項１１に記載の車載内燃機関の冷却装置において、
前記制御手段は前記一方の冷却系の電動ファンの駆動電力のみを減少させたときの単位電力当たりの放熱量の減少量が前記他方の冷却系の電動ウォータポンプの駆動電力のみを減少させたときの単位電力当たりの放熱量の減少量よりも小さい場合には前記一対の冷却系の電動ファンの駆動電力を減少させる一方、前記一方の冷却系の電動ファンの駆動電力のみを減少させたときの単位電力当たりの放熱量の減少量が前記他方の冷却系の電動ウォータポンプの駆動電力のみを減少させたときの単位電力当たりの放熱量の減少量よりも大きい場合には前記一対の冷却系の電動ウォータポンプの駆動電力を減少させる
ことを特徴とする車載内燃機関の冷却装置。 The cooling device for an in-vehicle internal combustion engine according to claim 11,
When the control means decreases only the drive power of the electric fan of the other cooling system, the amount of decrease in the heat dissipation amount per unit power when only the drive power of the electric fan of the one cooling system decreases When the amount of heat dissipation per unit power is smaller than the amount of decrease in the heat dissipation amount, the drive power of the pair of cooling system electric fans is reduced, while only the drive power of the one cooling system electric fan is reduced. If the amount of decrease in heat dissipation per unit power is greater than the amount of decrease in heat dissipation per unit power when only the drive power of the electric water pump of the other cooling system is decreased, the pair of cooling systems A cooling device for an on-vehicle internal combustion engine, characterized in that the driving power of an electric water pump is reduced.