EP2863030A1 - Cooling controller for internal combustion engines - Google Patents
Cooling controller for internal combustion engines Download PDFInfo
- Publication number
- EP2863030A1 EP2863030A1 EP20120879327 EP12879327A EP2863030A1 EP 2863030 A1 EP2863030 A1 EP 2863030A1 EP 20120879327 EP20120879327 EP 20120879327 EP 12879327 A EP12879327 A EP 12879327A EP 2863030 A1 EP2863030 A1 EP 2863030A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- cooling
- water
- clogging
- amount
- temperature
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Images
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01P—COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES
- F01P7/00—Controlling of coolant flow
- F01P7/14—Controlling of coolant flow the coolant being liquid
- F01P7/16—Controlling of coolant flow the coolant being liquid by thermostatic control
- F01P7/165—Controlling of coolant flow the coolant being liquid by thermostatic control characterised by systems with two or more loops
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01P—COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES
- F01P7/00—Controlling of coolant flow
- F01P7/14—Controlling of coolant flow the coolant being liquid
- F01P7/16—Controlling of coolant flow the coolant being liquid by thermostatic control
- F01P7/167—Controlling of coolant flow the coolant being liquid by thermostatic control by adjusting the pre-set temperature according to engine parameters, e.g. engine load, engine speed
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01P—COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES
- F01P11/00—Component parts, details, or accessories not provided for in, or of interest apart from, groups F01P1/00 - F01P9/00
- F01P11/14—Indicating devices; Other safety devices
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01P—COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES
- F01P3/00—Liquid cooling
- F01P3/20—Cooling circuits not specific to a single part of engine or machine
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01P—COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES
- F01P5/00—Pumping cooling-air or liquid coolants
- F01P5/10—Pumping liquid coolant; Arrangements of coolant pumps
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01P—COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES
- F01P2023/00—Signal processing; Details thereof
- F01P2023/08—Microprocessor; Microcomputer
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01P—COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES
- F01P2025/00—Measuring
- F01P2025/60—Operating parameters
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01P—COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES
- F01P2031/00—Fail safe
- F01P2031/30—Cooling after the engine is stopped
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01P—COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES
- F01P2050/00—Applications
- F01P2050/24—Hybrid vehicles
Definitions
- the present invention relates to a controller for a cooling system of an internal combustion engine, and more particularly, to a system for controlling circulation of cooling water.
- An internal combustion engine is heated by burning fuel, and if a temperature thereof is raised excessively, an abnormal combustion is caused and an energy efficiency of the engine is worsened. Therefore, the engine is provided with a cooling system.
- the engine is cooled by a water cooling method, an oil cooling method, and an air cooling method. The abnormal combustion would be caused if the engine is cooled insufficiently, and by contrast, fuel combustion would be hindered if the engine is cooled excessively regardless of the cooling method.
- Japanese Patent No. 4883225 describes a cooling system for a vehicle comprised of a first water circuit for circulating cooling water through an internal combustion engine, and a second water circuit for circulating the cooling water through a waste heat recovery system without passing through the internal combustion engine.
- a flow rate of the cooling water circulating in the first water circuit is reduced by reducing an opening degree of a valve, and the cooling waters in those circuits are mixed by increasing an opening degree of the valve.
- a valve element of the valve has a hole for letting through the cooling water even if the valve is closed.
- the cooling system is configured to judge the valve stuck at a closing position if a temperature of the water in the first cooling circuit is higher than a predetermined value, and a difference between temperatures of the cooling waters in the first cooling circuit and the second cooling water circuit is greater than a predetermined other value.
- Japanese Patent Laid-Open No. 2007-46469 describes a waste heat recovery system having a cooling passage branching out of a radiation circuit for cooling an engine to let the cooling water through a heat recovery device.
- a valve is disposed on the cooling passage, and the valve is comprised of a through hole for flowing cooling water, and a narrow hole perpendicular to the through hole. Given that the valve is turned to be opened, the through hole is connected to the cooling passage so that the cooling water is allowed to flow through the cooling passage. By contrast, given that the valve is turned to be closed, the through hole is oriented to be perpendicular to the cooling passage. In this case, however, the narrow hole is connected to the cooling passage so that the cooling water is still allowed to be delivered to the cooling passage in a small amount through the narrow hole.
- the cooling water is still allowed to flow through the hole formed in the valve element even if a valve sticks at a position where an opening degree of the valve is narrow. However, if the hole is clogged by foreign matter, the cooling water would not be allowed to circulate within the first cooling circuit.
- the cooling control system is comprised of: a cooling circuit for circulating cooling water via a water pump and the engine to cool the engine; a bypass circuit for circulating the cooling water without passing through the engine; a first temperature sensor that is disposed on the cooling circuit to detect a temperature of the cooling water flowing therethrough; a second temperature sensor that is disposed on the bypass circuit to detect a temperature of the cooling water flowing therethrough; a switching valve that is closed to reduce a flow rate of the cooling water flowing through the cooling circuit, and that is opened to increase the flow rate of the cooling water flowing through the cooling circuit; and a water passage that allows the cooling water to flow through the cooling circuit in a small amount when the switching valve is closed.
- the cooling control system is provided with an estimation means that is configured to estimate an amount of clogging of the water passage based on a temporal change in a temperature difference between a temperature of the cooling water detected by the first temperature sensor and a temperature of the cooling water detected by the second temperature sensor, under a condition in that the engine is stopped, the switching valve is closed, and the water pump is driven.
- the estimation means may be configured to estimate the amount of clogging of the water passage by subtracting the temperature difference of a case in which the water pump is not driven from the temperature difference of a case in which the water pump is driven, in case an external temperature is lower than a predetermined temperature.
- the estimation means may also be configured to estimate a current amount of clogging of the water passage while reducing a drive frequency of the water pump to be less than that of the previous case if a current estimated value of the amount of clogging is smaller than a first threshold value. In this case, if the current estimated value of the amount of clogging is larger than the first threshold value, the estimation means estimates a current amount of clogging of the water passage while increasing the drive frequency of the water pump to be more than that of the previous case.
- the estimation means may also be configured to estimate the amount of clogging of the water passage by increasing the drive frequency of the water pump with an increase in a speed of a vehicle having the engine.
- the estimation means may also be configured to estimate the amount of clogging of the water passage while increasing the drive frequency of the water pump if the estimated value of the amount of clogging is larger than the first threshold value but smaller than a second threshold value. In this case, the estimation means opens the switching valve if the estimated value of the amount of clogging is smaller than the second threshold value.
- the control system is configure to estimate an amount of clogging of the water passage based on such temporal change in the temperature difference so that an accuracy for estimating the amount of clogging can be improved.
- the drive frequency of the water pump is reduced to be less than the previous value if a current estimated value of the amount of clogging is smaller than a first threshold value. Therefore, accuracy for estimating a current amount of clogging can be improved in comparison with that for estimating a previous amount of clogging.
- the cooling control system of the present invention may be applied to a hybrid vehicle in which a prime mover is comprised of an internal combustion engine and an electric motor.
- a prime mover is comprised of an internal combustion engine and an electric motor.
- the vehicle In this case, therefore, the amount of clogging can be estimated promptly by increasing the drive frequency of the water pump.
- the vehicle is powered mainly by the motor rather than the engine. In this case, therefore, the accuracy for estimating the amount of clogging can be improved by reducing the drive frequency of the water pump.
- the switching valve is opened under a condition where the engine has not yet been warmed-up sufficiently and the amount of clogging of the water passage is larger than the first threshold value but smaller than a second threshold value, the engine may be overly cooled. In this case, therefore, a flow rate of the cooling water circulating within the cooling circuit is increased by increasing the drive frequency of the water pump. If the amount of clogging of the water passage is larger than the second threshold value, the flow rate of the cooling water circulating within the cooling circuit is increased by opening the switching valve.
- the cooling control system is comprised of a circuit for circulating cooling water passing through an internal combustion engine of a vehicle, and a circuit for circulating the cooling water without passing through the engine.
- a solenoid valve is disposed in the cooling control system.
- the solenoid valve is adapted not to completely block a flow of the cooling water circulating within the circuit passing through the engine, even if it is closed to block the circuit passing through the engine.
- the cooling control system of the present invention is applied to a hybrid vehicle in which a prime mover is comprised of an internal combustion engine and a plurality of electric motors.
- a drive mode can be selected from a hybrid mode where the vehicle is powered by both of the engine and the motor, a motor mode where the vehicle is powered by the motor(s) while stopping the engine and so on depending on a vehicle speed.
- the engine may be driven when launching the vehicle, and stopped when stopping the vehicle.
- the engine is selectively operated depending on the selected drive mode and the running condition of the vehicle.
- a gasoline engine, a diesel engine, a natural gas engine may be used as the engine 1 of the invention, and a rotational speed and an output torque of the engine 1 can be controlled electrically.
- a conventional AC motor serves as a motor and a generator may be used as the electric motor.
- Fig. 12 shows a preferred example of the cooling control system of the present invention.
- a not shown water jacket is attached to a cylinder block and a cylinder head.
- the cooling control system is provided with an electric water pump 2 for supplying the cooling water to the water jacket.
- the water pump 2 is comprised of a motor and an impeller rotated by the motor to deliver the cooling water.
- a discharging amount and a discharging pressure of the water pump 2 can be altered by electrically changing a rotational speed of the motor.
- the water pump 2 is comprised of a PWM (Pulse Width Modulation) circuit for controlling a motor speed of the water pump 2 by a PWM method in response to a command signal from a below-mentioned electronic control unit.
- PWM Pulse Width Modulation
- a rotational speed of the motor is raised by increasing a duty cycle thereof, and lowered by decreasing the duty cycle thereof.
- a discharging port of the water pump 2 is connected with the water jacket of the engine 1 through a feeding conduit 3, and a suction port of the water pump 2 is connected with the water jacket of the engine 1 through a return conduit 4.
- a first temperature sensor is arranged in the vicinity of a connection between the water jacket and the return conduit 4.
- the return conduit 4 is also connected to a radiator 6.
- the radiator 6 is adapted to exchange heat between the cooling water warmed as a result of drawing heat from the engine 1 and the external air thereby cooling the cooling water.
- the cooling water thus cooled by the radiator 6 is delivered to the suction port of the water pump 2 through a conventional thermostat 7.
- the thermostat 7 is adapted to allow the cooling water to flow toward the radiator 6 if the temperature of the cooling water is higher than a predetermined temperature, and to inhibit the cooling water to flow toward the radiator 6 if the temperature of the cooling water is lower than a predetermined temperature.
- the predetermined temperature is set to a value that can determine whether or not warm-up of the engine 1 has been completed. In the following explanation, the predetermined temperature thus determined will be called the "warm-up temperature".
- the thermostat 7 always allows the cooling water to flow from a below-mentioned bypass conduit 8 toward the return conduit 4.
- the bypass conduit 8 connects the feeding conduit 3 to the return conduit 4, and a second temperature sensor 9 is disposed on the bypass conduit 8.
- a branch conduit 10 branches out from the return conduit 4 between the engine 1 and the radiator 6 to be connected to the bypass conduit 8, and a solenoid valve 11 is disposed on the branch conduit 10 to alter a flow rate of the cooling water supplied to the water jacket by selectively opening and closing the branch conduit 10.
- the solenoid valve 11 is closed when energized so that the flow rate of the cooling water flowing toward the water jacket is reduced.
- the solenoid valve 11 is opened when unenergized so that the flow rate of the cooling water flowing toward the water jacket is increased.
- the solenoid valve 11 is provided with a water passage indicated by a broken line in Fig. 12 for allowing the cooling water to flow through the branch conduit 10 when the solenoid valve 11 is closed.
- the water passage may be formed by forming a through hole or a notch penetrating through a valve element that selectively opens and closes input and output ports of the solenoid valve 11.
- an additional pipe may be arranged to connect an upstream side and a downstream side of the solenoid valve 11 to serve as the water passage.
- a cross-section of the water passage is smaller than that of the branch conduit 10.
- the solenoid valve 11 is connected to an auxiliary battery.
- the auxiliary battery is also connected to a main battery through a DC-DC converter to provide power to auxiliaries such as an air conditioner and a headlight.
- the hydraulic control unit is provided with an electronic control unit 12 serving as the controller of the present invention.
- the electronic control unit 12 will be abbreviated as the "ECU” 12 for the sake of convenience.
- the ECU 12 is comprised mainly of a microcomputer configured to carry out a calculation on the basis of input data and preinstalled data, and calculation results are sent to the solenoid valve 11 and the water pump 2 in the form of command signals. For example, signals from the temperature sensors 5 and 9, an engine speed sensor, a vehicle speed sensor, an igniter and so on are sent to the ECU 12.
- the temperature of the cooling water is lower than the warm-up temperature but higher than another reference temperature that is slightly lower than the warm-up temperature, the temperature of the cooling water has not yet been raised sufficiently.
- another reference temperature will be called the "pre-warm-up temperature”.
- the cooling water is prevented from flowing toward the radiator 6 by the thermostat 7 but the solenoid valve 11 is unenergized to be opened to raise the temperature of the cooling water in the water jacket in a mild manner.
- the cooling water partially flows through the feeding conduit 3, the water jacket, the branch conduit 10 and the return conduit 4, and remaining cooling water flows through the feeding conduit 3, the bypass conduit 8 and the return conduit 4.
- the cooling water is allowed by the thermostat 7 to flow toward the radiator 6.
- the solenoid valve 11 is opened so that the cooling water is partially delivered to the radiator 6 to be cooled. That is, a mixture of the cooling water thus cooled by the radiator 6 and the cooling water circulating within another circuit is discharged from the water pump 2 to circulate within each circuit. For this reason, the temperature of the cooling water in the water jacket will not be raised excessively. Accordingly, the circuit passing through the water jacket serves as the cooling circuit of the invention, and the circuit passing through the bypass conduit 8 serves as the bypass circuit of the invention.
- the cooling control system of the present invention is configured to estimate an amount of clogging of the water passage for delivering the cooling water to the water jacket in case the solenoid valve 11 is closed.
- an amount of clogging can be represented by a reduction percentage (%) of a cross-sectional area of the water passage that is clogged by foreign material such as water stain and dust. Specifically, if the amount of clogging is 15%, this means that 15% of the cross-sectional area of the water passage is closed by the foreign material.
- Fig. 1 there is shown a flowchart explaining the first control example of the cooling control system for the engine. The routine shown in Fig. 1 is repeated at predetermined internal.
- a temperature Thw of the cooling water flowing out of the water jacket of the engine 1 is detected by the first temperature sensor 5. Meanwhile, a temperature Thb of the cooling water flowing through the bypass conduit 8 is detected by the second temperature sensor 9. Then, a temperature difference ⁇ Tini is calculated by subtracting the temperature Thb of the cooling water flowing through the bypass conduit 8 from the temperature Thw of the cooling water flowing out of the engine 1.
- the temperature difference ⁇ Tini thus calculated will be called the "initial temperature difference" ⁇ Tini in the following description.
- it is determined whether or not the initial temperature difference ⁇ Tini is larger than a predetermined reference value Tdet, and whether or not the engine 1 is stopped.
- the reference value Tdet is a temperature difference determined based on a result of experimentation or simulation that is possible to determine an amount of clogging of the water passage within a predetermined period of time.
- the reference value Tdet is set to 20 degrees C.
- an engine stop can be determined based on a current running condition of the vehicle, a current driving mode, a current vehicle speed and so on. If the initial temperature difference ⁇ Tini is smaller than the reference value Tdet, or if the engine 1 is under operation so that the answer of step S1 is NO, the routine is returned without carrying out any specific control.
- the initial temperature difference ⁇ Tini is larger than the reference value Tdet and the engine 1 is stopped so that the answer of step S1 is YES
- the initial temperature difference ⁇ Tini is saved to be used at after-mentioned step S4.
- the water pump 2 is activated and the solenoid valve 11 is closed (at step S2). Specifically, the solenoid valve 11 is closed to block the bypass conduit 10. In this case, however, the cooling water is still allowed to flow through the water passage of the solenoid valve 11. In this situation, the drive duty cycle of the water pump 2 may be adjusted arbitrarily depending on the running condition of the vehicle.
- step S3 it is determined whether or not a preset time t1 has elapsed (at step S3). Given that the water passage is clogged heavily, a flow rate of the cooling water flowing therethrough is reduced. This means that a heat transfer via the cooling water is reduced. Consequently, a difference between the detection values of the temperature sensors 5 and 9 is widened.
- the flow rate of the cooling water flowing therethrough is comparatively larger than that of the case in which the water passage is clogged heavily. That is, a heat transfer via the cooling water is comparatively large so that the difference between the detection values of the temperature sensors 5 and 9 is decreased.
- Fig. 2 shows an example of a map determining the waiting time with respect to the drive duty cycle of the water pump 2.
- the drive duty cycle of the water pump 2 is large, the flow rate of the cooling water flowing through the water passage is increased. In this case, therefore, the waiting time is set to a short period of time.
- the waiting time is set to a long period of time.
- step S3 is repeated until the preset time t1 has elapsed.
- the preset time t1 has elapsed so that the answer of step S3 is YES
- the temperature Thw (now) of the cooling water flowing out of the engine 1 is detected again by the first temperature sensor 5
- the temperature Thb (now) of the cooling water flowing through the bypass conduit 8 is detected again by the second temperature sensor 9.
- a temperature difference ⁇ Tnow is calculated by subtracting the temperature Thb (now) of the cooling water flowing through the bypass conduit 8 from the temperature Thw (now) of the cooling water flowing out of the engine 1 (at step S4).
- an estimated value of an amount of clogging of the water passage is calculated (at step S5).
- the estimated value of an amount of clogging is calculated by the following procedures. Referring now to Fig. 3 , there is shown a graph indicating a relation between the initial temperature difference ⁇ Tini and the current temperature difference ⁇ Tnow. As can be seen from Fig. 3 , in case the water passage is not clogged with foreign matter or an amount of clogging is small, the cooling water is allowed to flow through the water jacket smoothly so that the current temperature difference ⁇ Tnow is small. By contrast, in case the water passage is completely clogged with the foreign matter or the amount of clogging is large, the cooling water remains in the water jacket.
- the vertical axis represents a difference ⁇ Td1 between the initial temperature difference ⁇ Tini and the current temperature difference ⁇ Tnow.
- the difference ⁇ Td1 is large in case the amount of clogging of the water passage is small, and the difference ⁇ Td1 is small in case the amount of clogging of the water passage is large. This means that the amount of clogging is large if the difference ⁇ Td1 between ⁇ Tini and ⁇ Tnow is small. Accordingly, the amount of clogging of the water passage can be estimated with reference to a map shown in Fig. 4 that determines a relation between the clogging amount and the difference ⁇ Td1.
- the threshold value PV1 is set to 15%. If the amount of clogging of the water passage estimated at step S5 is smaller than the threshold value PV1 so that the answer of step S6 is NO, the routine is returned without carrying out any specific control. By contrast, if the amount of clogging of the water passage estimated at step S5 is larger than the threshold value PV1 so that the answer of step S6 is YES, the solenoid valve 11 is opened (at step S7). Consequently, the cooling water flowing out of the water jacket is allowed to flow through the branch conduit 10. Accordingly, the threshold value PV1 corresponds to the first threshold value of the present invention.
- the cooling control system of the present invention is configured to estimate an amount of clogging of the water passage, and to open the solenoid valve 11 if the estimated value of the clogging amount is larger than the threshold value PV1. According to the present invention, therefore, the cooling water is allowed to circulate through the water jacket even if the water passage is clogged with foreign material.
- Fig. 5 there is shown a flowchart explaining the second control example of the cooling control system for the engine.
- the routine shown in Fig. 5 is also repeated at predetermined interval.
- common numbers are allotted to the steps identical to those in Fig. 1 .
- step S8 it is determined whether or not an external temperature measured by a not shown sensor is lower than a predetermined threshold value (at step S8). Given that the external temperature is low, a temperature of the cooling water is lowered naturally and an accuracy of the above-explained estimation of clogging amount based on the temperature difference may be deteriorated.
- the threshold value for the external temperature is set to a value sufficiently lower than the above-mentioned warm-up temperature. If the external temperature is higher than the threshold value so that the answer of step S8 is NO, the routine advances to step S1 of Fig. 1 to carry out the control shown in Fig. 1 .
- step S9 the routine advances sequentially to steps S2 and S9 to stop the water pump 2 (at step S9). Then, it is determined whether or not a preset time t2 has elapsed from a point at which the water pump 2 was stopped (at step S10). As the preset time t1 used at step S3 shown in Fig. 1 , the preset time t2 is the waiting time until the temperature of the cooling water flowing through the water passage starts changing. The determination of step S10 is also repeated until the preset time t2 has elapsed.
- a lowered amount ⁇ Tcold of the temperature of the cooling water lowered by the external temperature is calculated (at step S11).
- a temperature Thw (c) of the cooling water flowing out of the engine 1 and a temperature Thb (c) of the cooling water flowing through the bypass conduit 8 are detected when the preset time t2 has elapsed.
- the lowered amount ⁇ Tcold is calculated by subtracting a difference between the temperatures Thw (c) and Thb (c) from the initial temperature difference ⁇ Tini.
- step S12 the water pump 2 is activated (at step S12). Thereafter, the routine advances to above-explained step S3 to determine whether or not the preset time t1 has elapsed. If the preset time t1 has elapsed so that the answer of step S3 is YES, the routine advances to above-explained step S4.
- step S4 specifically, the current temperatures Thw (now) of the cooling water flowing out of the engine 1 and Thb (now) of the cooling water flowing through the bypass conduit 8 under the condition where the water pump 2 is activated are detected by the temperature sensors 5 and 9. As described, at step S4, a current temperature difference ⁇ Tnow is calculated by subtracting the temperature Thb (now) from the temperature Thw (now).
- an estimated value of an amount of clogging of the water passage is calculated while eliminating an influence of the external temperature such as the lowered amount ⁇ Tcold (at step S13).
- the difference ⁇ Td1 between the initial temperature difference ⁇ Tini and the current temperature difference ⁇ Tnow is calculated.
- the amount of clogging is large if the difference ⁇ Td2 is large.
- the amount of clogging of the water passage can be estimated with reference to a map shown in Fig. 6 that determines a relation between the clogging amount and the difference ⁇ Td2. Then, the routine advances to step S6 shown in Fig. 1 .
- the estimated value of an amount of clogging of the water passage can be calculated while eliminating an influence of the external temperature so that the accuracy of estimating the amount of clogging can be improved. That is, the cooling control system will not erroneously estimate a fact that the clogging amount of the water passage is small or zero if the water passage is clogged with the foreign material.
- Fig. 7 there is shown a flowchart explaining the third control example of the cooling control system configured to accurately estimate an amount of clogging of the water passage in case the amount of clogging during previous trip is larger than the threshold value PV1. That is, the example shown in Fig. 7 is configured to estimate the clogging amount of the water passage without determining a clogging of the water passage erroneously under a situation where the water passage is not clogged with foreign material.
- common numbers are allotted to the steps identical to those in Fig. 1 .
- step S14 it is determined whether or not an estimated value of an amount of clogging of the water passage calculated during the previous trip is smaller than the threshold value PV1 (at step S14). If the estimated value of an amount of clogging calculated during the previous trip is smaller than the threshold value PV1 so that the answer of step S14 is YES, the drive duty cycle of the water pump 2 for the current trip is set to be less than that for the previous trip (at step S15). If the estimated value of an amount of clogging calculated during the previous trip is smaller than the threshold value PV1, the control system estimates a fact that the amount of clogging is smaller than the threshold value PV1 also during the current trip. In this case, following controls are carried out while reducing the drive duty cycle of the water pump 2 to reduce electric consumption. For example, given that the drive duty cycle of the water pump 2 was 50% during the previous trip, the drive duty cycle of the water pump 2 is reduced to 40% during the current trip.
- step S14 the drive duty cycle of the water pump 2 is set to the maximum value (at step S16). Consequently, the discharging amount of the water pump 2 can be increased to increase the flow rate of the cooling water flowing through the water jacket without opening the solenoid valve 11.
- step S17 the routine advances to step S3 to determine whether or not the preset time t1 has elapsed.
- An amount of clogging during the current trip is estimated at step S5, and then, it is determined whether or not the estimated value of the amount of clogging of the water passage during the current trip is larger than another threshold value PV2 (at step S18).
- the threshold value PV2 is set to a value larger than the threshold value PV1, for example, set to 60%. If the estimated value of an amount of clogging during the current trip is larger than the threshold value PV2, the control system determines a fact that the water passage is clogged abnormally with foreign material. In this case, the solenoid valve 11 is opened (at step S19).
- step S20 it is determined whether or not the estimated value of an amount of clogging is larger than the threshold value PV1 (at step S20). If the estimated value of an amount of clogging of the water passage is smaller than the threshold value PV1 so that the answer of step S20 is NO, the control system determines a fact that the water passage is in a normal condition without being clogged with foreign material (at step S21). By contrast, if the estimated value of an amount of clogging of the water passage is larger than the threshold value PV1 so that the answer of step S20 is YES, the routine advances to step S22.
- the estimated value of an amount of clogging of the water passage is larger than the threshold value PV1 but smaller than the threshold value PV2. Consequently, the control system makes a determination of a quasi-clogging of the water passage.
- a drive duty cycle of the water pump 2 may be calculated in a manner such hat the accuracy for estimating an amount of clogging for the next trip will be improved in comparison with that during the current trip. In this case, the amount of clogging will be estimated based on the drive duty cycle of the water pump 2 calculated at step S22.
- the amount of clogging during the current trip is estimated while increasing the drive duty cycle of the water pump 2.
- the cooling water is allowed to flow through the water jacket smoother than the case in which the drive duty cycle of the water pump 2 is small so that the accuracy for estimating the amount of clogging can be improved in comparison with that during the previous trip.
- Fig. 8 there is shown a flowchart explaining the fourth control example of the cooling control system configured to alter the drive duty cycle of the water pump 2 depending on the vehicle speed to estimate an amount of clogging of the water passage.
- the control example shown in Fig. 8 may be applied to a hybrid vehicle in which a prime mover is comprised of an engine and a motor.
- common numbers are allotted to the steps identical to those in Fig. 1 .
- step S1 After making a determination of step S1, the initial temperature difference ⁇ Tini is saved and the drive duty cycle of the water pump 2 is adjusted according to the vehicle speed (at step S23).
- the drive duty cycle of the water pump 2 may be determined with reference to a preinstalled map shown in Fig. 9 . Given that the vehicle speed is higher than a predetermined speed, the engine 1 will be operated frequently and heated significantly. In this case, therefore, the drive duty cycle of the water pump 2 is increased to the maximum value. To this end, the vehicle speed can be detected by a not shown speed sensor. Then, the routine advances to step S3.
- the vehicle is powered by the motor more frequently rather than powered by the engine.
- the drive duty cycle of the water pump 2 can be reduced in comparison with the case in which the vehicle runs at a high speed so that the amount of clogging of the water passage can be estimated more accurately without operating the engine 1.
- a flow rate of the cooling water can be reduced so that the engine 1 can be prevented from being cooled excessively.
- the hybrid vehicle runs at a high speed, the vehicle is powered by the engine more frequently rather than powered by the motor. In this case, therefore, an amount of clogging of the water passage can be estimated promptly while stopping the engine 1 by increasing the drive duty cycle of the water pump 2.
- Fig. 10 there is shown a flowchart explaining the fifth control example of the cooling control system configured to alter a flow rate of the cooling water flowing through the water jacket while closing the solenoid valve 11 depending on an estimated value of clogging of the water passage.
- common numbers are allotted to the steps identical to those in Fig. 1 .
- step S5 it is determined whether or not an estimated value of an amount of clogging is larger than a still another threshold value PV3 (at step S24).
- the threshold value PV3 is set to 50% that is larger than the threshold value PV 1 but smaller than the threshold value PV2. If the estimated value of the amount of clogging is larger than the threshold value PV3 so that the answer of step S24 is YES, the solenoid valve 11 is opened (at step S25). That is, if the estimated value of an amount of clogging is large, the cooling water flowing out of the water jacket is allowed to circulate through the branch conduit 10.
- step S26 it is determined whether or not the estimated value of the amount of clogging is larger than the threshold value PV1 (at step S26). If the estimated value of the amount of clogging is smaller than the threshold value PV1 so that the answer of step S26 is NO, the routine is returned.
- a coefficient for correcting the drive duty cycle of the water pump 2 is calculated to alter the drive duty cycle in accordance with the estimated value of the amount of clogging (at step S27).
- the correction coefficient may be determined according to the estimated value of an amount of clogging with reference to a preinstalled map shown in Fig. 11 .
- the drive duty cycle is corrected by the correction coefficient thus calculated (at step S28). Specifically, the drive duty cycle of the water pump 2 is calculated by multiplying the current drive duty cycle by the correction coefficient, and the water pump 2 is driven in accordance with the drive duty cycle thus corrected. In this case, if the estimated value of the amount of clogging is larger than 15% but smaller than 50%, a discharging amount of the water pump 2 is increased in accordance with the correction coefficient determined according to the estimated value of the amount of clogging. It is to be noted that the maximum value of the drive duty cycle to be corrected by the correction coefficient is limited to a value that can drive the water pump 2 without reducing fuel economy, on the basis of a result of experimentation or simulation.
- the fuel economy will not be reduced even if the drive duty cycle of the water pump 2 is increased to increase a flow rate of the cooling water flowing through the water jacket.
- the solenoid valve 11 is opened to avoid such reduction in the fuel economy.
- the solenoid valve 11 will not be opened if the estimated value of the amount of clogging is smaller than the threshold value PV3 so that the engine 1 can be prevented from being cooled overly.
- the solenoid valve 11 is opened. In this case, therefore, the drive duty cycle of the water pump 2 does not have to be increased so that the fuel economy will not be reduced.
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Combined Controls Of Internal Combustion Engines (AREA)
Abstract
Description
- The present invention relates to a controller for a cooling system of an internal combustion engine, and more particularly, to a system for controlling circulation of cooling water.
- An internal combustion engine is heated by burning fuel, and if a temperature thereof is raised excessively, an abnormal combustion is caused and an energy efficiency of the engine is worsened. Therefore, the engine is provided with a cooling system. In the conventional art, the engine is cooled by a water cooling method, an oil cooling method, and an air cooling method. The abnormal combustion would be caused if the engine is cooled insufficiently, and by contrast, fuel combustion would be hindered if the engine is cooled excessively regardless of the cooling method.
- For example, Japanese Patent No.
4883225 4883225 - Japanese Patent Laid-Open No.
2007-46469 - According to the cooling system taught by Japanese Patent No.
4883225 - In order to solve the foregoing technical problems, it is therefore an object of this invention to provide a cooling control system for an internal combustion engine that can estimate a clogging amount of a hole for letting through coolant with improved accuracy even if a valve is closed.
- The cooling control system is comprised of: a cooling circuit for circulating cooling water via a water pump and the engine to cool the engine; a bypass circuit for circulating the cooling water without passing through the engine; a first temperature sensor that is disposed on the cooling circuit to detect a temperature of the cooling water flowing therethrough; a second temperature sensor that is disposed on the bypass circuit to detect a temperature of the cooling water flowing therethrough; a switching valve that is closed to reduce a flow rate of the cooling water flowing through the cooling circuit, and that is opened to increase the flow rate of the cooling water flowing through the cooling circuit; and a water passage that allows the cooling water to flow through the cooling circuit in a small amount when the switching valve is closed. In order to achieve the above-explained objective, according to the present invention, the cooling control system is provided with an estimation means that is configured to estimate an amount of clogging of the water passage based on a temporal change in a temperature difference between a temperature of the cooling water detected by the first temperature sensor and a temperature of the cooling water detected by the second temperature sensor, under a condition in that the engine is stopped, the switching valve is closed, and the water pump is driven.
- The estimation means may be configured to estimate the amount of clogging of the water passage by subtracting the temperature difference of a case in which the water pump is not driven from the temperature difference of a case in which the water pump is driven, in case an external temperature is lower than a predetermined temperature.
- The estimation means may also be configured to estimate a current amount of clogging of the water passage while reducing a drive frequency of the water pump to be less than that of the previous case if a current estimated value of the amount of clogging is smaller than a first threshold value. In this case, if the current estimated value of the amount of clogging is larger than the first threshold value, the estimation means estimates a current amount of clogging of the water passage while increasing the drive frequency of the water pump to be more than that of the previous case.
- The estimation means may also be configured to estimate the amount of clogging of the water passage by increasing the drive frequency of the water pump with an increase in a speed of a vehicle having the engine.
- The estimation means may also be configured to estimate the amount of clogging of the water passage while increasing the drive frequency of the water pump if the estimated value of the amount of clogging is larger than the first threshold value but smaller than a second threshold value. In this case, the estimation means opens the switching valve if the estimated value of the amount of clogging is smaller than the second threshold value.
- In the cooling system to which the present invention is applied, the heat would not be transported by the cooling water in the cooling circuit if the water passage is clogged and the switching valve is closed. Consequently, the difference between the temperature of the cooling water detected by the first temperature sensor and the temperature detected by the second temperature sensor is widened. By contrast, if the water passage is not clogged, the cooling water is allowed to transport the heat so that the above-mentioned temperature difference is reduced. That is, a temporal change in the above-mentioned temperature difference is increased with an increase in an amount of clogging of the water passage, and reduced with a reduction in the amount of clogging of the water passage. According to the present invention, the control system is configure to estimate an amount of clogging of the water passage based on such temporal change in the temperature difference so that an accuracy for estimating the amount of clogging can be improved.
- According to the present invention, the drive frequency of the water pump is reduced to be less than the previous value if a current estimated value of the amount of clogging is smaller than a first threshold value. Therefore, accuracy for estimating a current amount of clogging can be improved in comparison with that for estimating a previous amount of clogging.
- The cooling control system of the present invention may be applied to a hybrid vehicle in which a prime mover is comprised of an internal combustion engine and an electric motor. In case of propelling the hybrid vehicle at a high speed, the vehicle is powered mainly by the engine. In this case, therefore, the amount of clogging can be estimated promptly by increasing the drive frequency of the water pump. By contrast, in case of propelling the vehicle at a low speed, the vehicle is powered mainly by the motor rather than the engine. In this case, therefore, the accuracy for estimating the amount of clogging can be improved by reducing the drive frequency of the water pump.
- If the switching valve is opened under a condition where the engine has not yet been warmed-up sufficiently and the amount of clogging of the water passage is larger than the first threshold value but smaller than a second threshold value, the engine may be overly cooled. In this case, therefore, a flow rate of the cooling water circulating within the cooling circuit is increased by increasing the drive frequency of the water pump. If the amount of clogging of the water passage is larger than the second threshold value, the flow rate of the cooling water circulating within the cooling circuit is increased by opening the switching valve.
-
-
Fig. 1 is a flowchart showing a first example of a control carried out by the cooling control system of the present invention. -
Fig. 2 is an example of a map determining waiting time for commencement of temperature change in the cooling water with respect to a duty cycle. -
Fig. 3 is a graph indicating a relation between an initial temperature difference ΔTini and a current temperature difference ΔTnow. -
Fig. 4 is an example of a map determining a clogging amount with respect to a temperature difference ΔTd1. -
Fig. 5 is a flowchart showing a second example of a control carried out by the cooling control system of the present invention. -
Fig. 6 is an example of a map determining a clogging amount with respect to a temperature difference ΔTd2. -
Fig. 7 is a flowchart showing a third example of a control carried out by the cooling control system of the present invention. -
Fig. 8 is a flowchart showing a fourth example of a control carried out by the cooling control system of the present invention. -
Fig. 9 is an example of a map determining a pulse duty of a water pump with respect to a vehicle speed. -
Fig. 10 is a flowchart showing a fifth example of a control carried out by the cooling control system of the present invention. -
Fig. 11 is an example of a map for correcting a pulse duty of a water pump with respect to the clogging amount. -
Fig. 12 is a view schematically showing a preferred example of the cooling control system of engine according to the present invention. - Next, the present invention will be explained in more detail. The cooling control system according to the present invention is comprised of a circuit for circulating cooling water passing through an internal combustion engine of a vehicle, and a circuit for circulating the cooling water without passing through the engine. In order to switch the circuits depending on a temperature of the engine and a running condition of the vehicle including a launching condition, a stopping condition, and a vehicle speed, a solenoid valve is disposed in the cooling control system. Specifically, the solenoid valve is adapted not to completely block a flow of the cooling water circulating within the circuit passing through the engine, even if it is closed to block the circuit passing through the engine.
- For example, the cooling control system of the present invention is applied to a hybrid vehicle in which a prime mover is comprised of an internal combustion engine and a plurality of electric motors. In the hybrid vehicle, a drive mode can be selected from a hybrid mode where the vehicle is powered by both of the engine and the motor, a motor mode where the vehicle is powered by the motor(s) while stopping the engine and so on depending on a vehicle speed. In the hybrid vehicle, the engine may be driven when launching the vehicle, and stopped when stopping the vehicle. Thus, the engine is selectively operated depending on the selected drive mode and the running condition of the vehicle. For example, a gasoline engine, a diesel engine, a natural gas engine may be used as the
engine 1 of the invention, and a rotational speed and an output torque of theengine 1 can be controlled electrically. On the other hand, a conventional AC motor serves as a motor and a generator may be used as the electric motor. -
Fig. 12 shows a preferred example of the cooling control system of the present invention. In order to conduct heat away from theengine 1, a not shown water jacket is attached to a cylinder block and a cylinder head. To this end, the cooling control system is provided with anelectric water pump 2 for supplying the cooling water to the water jacket. Although not shown in detail, thewater pump 2 is comprised of a motor and an impeller rotated by the motor to deliver the cooling water. A discharging amount and a discharging pressure of thewater pump 2 can be altered by electrically changing a rotational speed of the motor. - Here will be briefly explained a structure of the
water pump 2. Although not especially shown, thewater pump 2 is comprised of a PWM (Pulse Width Modulation) circuit for controlling a motor speed of thewater pump 2 by a PWM method in response to a command signal from a below-mentioned electronic control unit. For example, a rotational speed of the motor is raised by increasing a duty cycle thereof, and lowered by decreasing the duty cycle thereof. - A discharging port of the
water pump 2 is connected with the water jacket of theengine 1 through afeeding conduit 3, and a suction port of thewater pump 2 is connected with the water jacket of theengine 1 through areturn conduit 4. In order to measure a temperature of the cooling water flowing out of the water jacket, a first temperature sensor is arranged in the vicinity of a connection between the water jacket and thereturn conduit 4. Thereturn conduit 4 is also connected to aradiator 6. As known in the prior art, theradiator 6 is adapted to exchange heat between the cooling water warmed as a result of drawing heat from theengine 1 and the external air thereby cooling the cooling water. The cooling water thus cooled by theradiator 6 is delivered to the suction port of thewater pump 2 through aconventional thermostat 7. - The
thermostat 7 is adapted to allow the cooling water to flow toward theradiator 6 if the temperature of the cooling water is higher than a predetermined temperature, and to inhibit the cooling water to flow toward theradiator 6 if the temperature of the cooling water is lower than a predetermined temperature. Specifically, the predetermined temperature is set to a value that can determine whether or not warm-up of theengine 1 has been completed. In the following explanation, the predetermined temperature thus determined will be called the "warm-up temperature". In addition, thethermostat 7 always allows the cooling water to flow from a below-mentionedbypass conduit 8 toward thereturn conduit 4. - The
bypass conduit 8 connects thefeeding conduit 3 to thereturn conduit 4, and a second temperature sensor 9 is disposed on thebypass conduit 8. Abranch conduit 10 branches out from thereturn conduit 4 between theengine 1 and theradiator 6 to be connected to thebypass conduit 8, and asolenoid valve 11 is disposed on thebranch conduit 10 to alter a flow rate of the cooling water supplied to the water jacket by selectively opening and closing thebranch conduit 10. - Here will be briefly explained a structure of the
solenoid valve 11. Thesolenoid valve 11 is closed when energized so that the flow rate of the cooling water flowing toward the water jacket is reduced. By contrast, thesolenoid valve 11 is opened when unenergized so that the flow rate of the cooling water flowing toward the water jacket is increased. Thesolenoid valve 11 is provided with a water passage indicated by a broken line inFig. 12 for allowing the cooling water to flow through thebranch conduit 10 when thesolenoid valve 11 is closed. For example, the water passage may be formed by forming a through hole or a notch penetrating through a valve element that selectively opens and closes input and output ports of thesolenoid valve 11. Alternatively, an additional pipe may be arranged to connect an upstream side and a downstream side of thesolenoid valve 11 to serve as the water passage. A cross-section of the water passage is smaller than that of thebranch conduit 10. Although not especially illustrated, thesolenoid valve 11 is connected to an auxiliary battery. The auxiliary battery is also connected to a main battery through a DC-DC converter to provide power to auxiliaries such as an air conditioner and a headlight. - In order to electrically control the
solenoid valve 11 and thewater pump 2, the hydraulic control unit is provided with an electronic control unit 12 serving as the controller of the present invention. In the following description, the electronic control unit 12 will be abbreviated as the "ECU" 12 for the sake of convenience. The ECU 12 is comprised mainly of a microcomputer configured to carry out a calculation on the basis of input data and preinstalled data, and calculation results are sent to thesolenoid valve 11 and thewater pump 2 in the form of command signals. For example, signals from thetemperature sensors 5 and 9, an engine speed sensor, a vehicle speed sensor, an igniter and so on are sent to the ECU 12. - Next, here will be briefly explained an action of the cooling control system shown in
Fig. 12 . For example, temperatures of theengine 1 and the cooling water are low just after starting-up theengine 1. In this situation, the cooling water is prevented from flowing toward theradiator 6 by thethermostat 7, and an electromagnetic coil of thesolenoid valve 11 is energized to close thesolenoid valve 11 so as to expedite warming-up of theengine 1. Accordingly, the cooling water discharged from thewater pump 2 mostly circulates within thefeeding conduit 3, thebypass conduit 8, and thereturn conduit 4, but partially flows through the water passage of thesolenoid valve 11. Consequently, a flow rate of the cooling water flowing through the water jacket is reduced so that the temperature of the cooling water in the water jacket can be raised promptly. In addition, since the cooling water is still allowed to flow through the water jacket in small amount, a local temperature difference in the water jacket can be reduced. - Given that the temperature of the cooling water is lower than the warm-up temperature but higher than another reference temperature that is slightly lower than the warm-up temperature, the temperature of the cooling water has not yet been raised sufficiently. In the following description, such another reference temperature will be called the "pre-warm-up temperature". In this case, the cooling water is prevented from flowing toward the
radiator 6 by thethermostat 7 but thesolenoid valve 11 is unenergized to be opened to raise the temperature of the cooling water in the water jacket in a mild manner. In this situation, specifically, the cooling water partially flows through thefeeding conduit 3, the water jacket, thebranch conduit 10 and thereturn conduit 4, and remaining cooling water flows through thefeeding conduit 3, thebypass conduit 8 and thereturn conduit 4. Consequently, the cooling water flowing through the water jacket is mixed with the cooling water flowing through thebypass conduit 8 at thebypass conduit 8 and thereturn conduit 4. As a result, the temperature of the cooling water in the water jacket is raised mildly in comparison with a case in which thesolenoid valve 11 is closed. - Given that the temperature of the cooling water is higher than the warm-up temperature, the cooling water is allowed by the
thermostat 7 to flow toward theradiator 6. In this case, thesolenoid valve 11 is opened so that the cooling water is partially delivered to theradiator 6 to be cooled. That is, a mixture of the cooling water thus cooled by theradiator 6 and the cooling water circulating within another circuit is discharged from thewater pump 2 to circulate within each circuit. For this reason, the temperature of the cooling water in the water jacket will not be raised excessively. Accordingly, the circuit passing through the water jacket serves as the cooling circuit of the invention, and the circuit passing through thebypass conduit 8 serves as the bypass circuit of the invention. - The cooling control system of the present invention is configured to estimate an amount of clogging of the water passage for delivering the cooling water to the water jacket in case the
solenoid valve 11 is closed. For example, an amount of clogging can be represented by a reduction percentage (%) of a cross-sectional area of the water passage that is clogged by foreign material such as water stain and dust. Specifically, if the amount of clogging is 15%, this means that 15% of the cross-sectional area of the water passage is closed by the foreign material. Referring now toFig. 1 , there is shown a flowchart explaining the first control example of the cooling control system for the engine. The routine shown inFig. 1 is repeated at predetermined internal. - First of all, a temperature Thw of the cooling water flowing out of the water jacket of the
engine 1 is detected by thefirst temperature sensor 5. Meanwhile, a temperature Thb of the cooling water flowing through thebypass conduit 8 is detected by the second temperature sensor 9. Then, a temperature difference ΔTini is calculated by subtracting the temperature Thb of the cooling water flowing through thebypass conduit 8 from the temperature Thw of the cooling water flowing out of theengine 1. The temperature difference ΔTini thus calculated will be called the "initial temperature difference" ΔTini in the following description. At step S1, accordingly, it is determined whether or not the initial temperature difference ΔTini is larger than a predetermined reference value Tdet, and whether or not theengine 1 is stopped. - Specifically, the reference value Tdet is a temperature difference determined based on a result of experimentation or simulation that is possible to determine an amount of clogging of the water passage within a predetermined period of time. In the example shown in
Fig. 1 , the reference value Tdet is set to 20 degrees C. For example, an engine stop can be determined based on a current running condition of the vehicle, a current driving mode, a current vehicle speed and so on. If the initial temperature difference ΔTini is smaller than the reference value Tdet, or if theengine 1 is under operation so that the answer of step S1 is NO, the routine is returned without carrying out any specific control. - By contrast, if the initial temperature difference ΔTini is larger than the reference value Tdet and the
engine 1 is stopped so that the answer of step S1 is YES, the initial temperature difference ΔTini is saved to be used at after-mentioned step S4. In addition, thewater pump 2 is activated and thesolenoid valve 11 is closed (at step S2). Specifically, thesolenoid valve 11 is closed to block thebypass conduit 10. In this case, however, the cooling water is still allowed to flow through the water passage of thesolenoid valve 11. In this situation, the drive duty cycle of thewater pump 2 may be adjusted arbitrarily depending on the running condition of the vehicle. - Then, it is determined whether or not a preset time t1 has elapsed (at step S3). Given that the water passage is clogged heavily, a flow rate of the cooling water flowing therethrough is reduced. This means that a heat transfer via the cooling water is reduced. Consequently, a difference between the detection values of the
temperature sensors 5 and 9 is widened. By contrast, given that the water passage is clogged not so heavily, the flow rate of the cooling water flowing therethrough is comparatively larger than that of the case in which the water passage is clogged heavily. That is, a heat transfer via the cooling water is comparatively large so that the difference between the detection values of thetemperature sensors 5 and 9 is decreased. In any cases, however, it takes some time before the temperature of the cooling water flowing through the water passage starts changing since thesolenoid valve 11 was closed. That is, the above-mentioned preset time t1 is the waiting time until the temperature of the cooling water flowing through the water passage starts changing.Fig. 2 shows an example of a map determining the waiting time with respect to the drive duty cycle of thewater pump 2. As can be seen fromFig. 2 , in case the drive duty cycle of thewater pump 2 is large, the flow rate of the cooling water flowing through the water passage is increased. In this case, therefore, the waiting time is set to a short period of time. By contrast, in case the drive duty cycle of thewater pump 2 is small, the flow rate of the cooling water flowing through the water passage is decreased. In this case, therefore, the waiting time is set to a long period of time. - If the preset time t1 has not elapsed yet so that the answer of step S3 is NO, the determination of step S3 is repeated until the preset time t1 has elapsed. By contrast, if the preset time t1 has elapsed so that the answer of step S3 is YES, the temperature Thw (now) of the cooling water flowing out of the
engine 1 is detected again by thefirst temperature sensor 5, and the temperature Thb (now) of the cooling water flowing through thebypass conduit 8 is detected again by the second temperature sensor 9. Then, a temperature difference ΔTnow is calculated by subtracting the temperature Thb (now) of the cooling water flowing through thebypass conduit 8 from the temperature Thw (now) of the cooling water flowing out of the engine 1 (at step S4). - Thereafter, an estimated value of an amount of clogging of the water passage is calculated (at step S5). The estimated value of an amount of clogging is calculated by the following procedures. Referring now to
Fig. 3 , there is shown a graph indicating a relation between the initial temperature difference ΔTini and the current temperature difference ΔTnow. As can be seen fromFig. 3 , in case the water passage is not clogged with foreign matter or an amount of clogging is small, the cooling water is allowed to flow through the water jacket smoothly so that the current temperature difference ΔTnow is small. By contrast, in case the water passage is completely clogged with the foreign matter or the amount of clogging is large, the cooling water remains in the water jacket. In this case, therefore, heat transfer via the cooling water is rather small. Consequently, the current temperature difference ΔTnow is widened in comparison with that of the case in which the amount of clogging is small. InFig. 3 , the vertical axis represents a difference ΔTd1 between the initial temperature difference ΔTini and the current temperature difference ΔTnow. As can be seen fromFig. 3 , the difference ΔTd1 is large in case the amount of clogging of the water passage is small, and the difference ΔTd1 is small in case the amount of clogging of the water passage is large. This means that the amount of clogging is large if the difference ΔTd1 between ΔTini and ΔTnow is small. Accordingly, the amount of clogging of the water passage can be estimated with reference to a map shown inFig. 4 that determines a relation between the clogging amount and the difference ΔTd1. - Then, it is determined whether or not the amount of clogging of the water passage estimated at step S5 is larger than a predetermined threshold value PV1 (at step S6). According to the preferred example, the threshold value PV1 is set to 15%. If the amount of clogging of the water passage estimated at step S5 is smaller than the threshold value PV1 so that the answer of step S6 is NO, the routine is returned without carrying out any specific control. By contrast, if the amount of clogging of the water passage estimated at step S5 is larger than the threshold value PV1 so that the answer of step S6 is YES, the
solenoid valve 11 is opened (at step S7). Consequently, the cooling water flowing out of the water jacket is allowed to flow through thebranch conduit 10. Accordingly, the threshold value PV1 corresponds to the first threshold value of the present invention. - Thus, the cooling control system of the present invention is configured to estimate an amount of clogging of the water passage, and to open the
solenoid valve 11 if the estimated value of the clogging amount is larger than the threshold value PV1. According to the present invention, therefore, the cooling water is allowed to circulate through the water jacket even if the water passage is clogged with foreign material. - Referring now to
Fig. 5 , there is shown a flowchart explaining the second control example of the cooling control system for the engine. The routine shown inFig. 5 is also repeated at predetermined interval. Here, in the flowchart shown inFig. 5 , common numbers are allotted to the steps identical to those inFig. 1 . According to the example shown inFig. 5 , if the answer of step S1 is YES, it is determined whether or not an external temperature measured by a not shown sensor is lower than a predetermined threshold value (at step S8). Given that the external temperature is low, a temperature of the cooling water is lowered naturally and an accuracy of the above-explained estimation of clogging amount based on the temperature difference may be deteriorated. Therefore, the threshold value for the external temperature is set to a value sufficiently lower than the above-mentioned warm-up temperature. If the external temperature is higher than the threshold value so that the answer of step S8 is NO, the routine advances to step S1 ofFig. 1 to carry out the control shown inFig. 1 . - By contrast, if the external temperature is lower than the threshold value so that the answer of step S8 is YES, the routine advances sequentially to steps S2 and S9 to stop the water pump 2 (at step S9). Then, it is determined whether or not a preset time t2 has elapsed from a point at which the
water pump 2 was stopped (at step S10). As the preset time t1 used at step S3 shown inFig. 1 , the preset time t2 is the waiting time until the temperature of the cooling water flowing through the water passage starts changing. The determination of step S10 is also repeated until the preset time t2 has elapsed. - If the preset time t2 has elapsed so that the answer of step S10 is YES, a lowered amount ΔTcold of the temperature of the cooling water lowered by the external temperature is calculated (at step S11). To this end, specifically, a temperature Thw (c) of the cooling water flowing out of the
engine 1, and a temperature Thb (c) of the cooling water flowing through thebypass conduit 8 are detected when the preset time t2 has elapsed. Then the lowered amount ΔTcold is calculated by subtracting a difference between the temperatures Thw (c) and Thb (c) from the initial temperature difference ΔTini. - Subsequently, the
water pump 2 is activated (at step S12). Thereafter, the routine advances to above-explained step S3 to determine whether or not the preset time t1 has elapsed. If the preset time t1 has elapsed so that the answer of step S3 is YES, the routine advances to above-explained step S4. At step S4, specifically, the current temperatures Thw (now) of the cooling water flowing out of theengine 1 and Thb (now) of the cooling water flowing through thebypass conduit 8 under the condition where thewater pump 2 is activated are detected by thetemperature sensors 5 and 9. As described, at step S4, a current temperature difference ΔTnow is calculated by subtracting the temperature Thb (now) from the temperature Thw (now). - Then, an estimated value of an amount of clogging of the water passage is calculated while eliminating an influence of the external temperature such as the lowered amount ΔTcold (at step S13). To this end, the difference ΔTd1 between the initial temperature difference ΔTini and the current temperature difference ΔTnow is calculated. In this case, however, the difference ΔTd1 thus calculated is affected by the external temperature. Therefore, a difference ΔTd2 from which an influence of the external temperature is eliminated is calculated as expressed by the following expression:
- Although not especially indicated in the accompanying drawings, as the case of the difference ΔTd1, the amount of clogging is large if the difference ΔTd2 is large. In this case, accordingly, the amount of clogging of the water passage can be estimated with reference to a map shown in
Fig. 6 that determines a relation between the clogging amount and the difference ΔTd2. Then, the routine advances to step S6 shown inFig. 1 . - Thus, according to the control example shown in
Fig. 5 , the estimated value of an amount of clogging of the water passage can be calculated while eliminating an influence of the external temperature so that the accuracy of estimating the amount of clogging can be improved. That is, the cooling control system will not erroneously estimate a fact that the clogging amount of the water passage is small or zero if the water passage is clogged with the foreign material. - Referring now to
Fig. 7 , there is shown a flowchart explaining the third control example of the cooling control system configured to accurately estimate an amount of clogging of the water passage in case the amount of clogging during previous trip is larger than the threshold value PV1. That is, the example shown inFig. 7 is configured to estimate the clogging amount of the water passage without determining a clogging of the water passage erroneously under a situation where the water passage is not clogged with foreign material. Here, in the flowchart shown inFig. 7 , common numbers are allotted to the steps identical to those inFig. 1 . - After the determination at step S1, it is determined whether or not an estimated value of an amount of clogging of the water passage calculated during the previous trip is smaller than the threshold value PV1 (at step S14). If the estimated value of an amount of clogging calculated during the previous trip is smaller than the threshold value PV1 so that the answer of step S14 is YES, the drive duty cycle of the
water pump 2 for the current trip is set to be less than that for the previous trip (at step S15). If the estimated value of an amount of clogging calculated during the previous trip is smaller than the threshold value PV1, the control system estimates a fact that the amount of clogging is smaller than the threshold value PV1 also during the current trip. In this case, following controls are carried out while reducing the drive duty cycle of thewater pump 2 to reduce electric consumption. For example, given that the drive duty cycle of thewater pump 2 was 50% during the previous trip, the drive duty cycle of thewater pump 2 is reduced to 40% during the current trip. - By contrast, if the estimated value of an amount of clogging calculated during the previous trip is larger than the threshold value PV1 so that the answer of step S14 is NO, the drive duty cycle of the
water pump 2 is set to the maximum value (at step S16). Consequently, the discharging amount of thewater pump 2 can be increased to increase the flow rate of the cooling water flowing through the water jacket without opening thesolenoid valve 11. - Thereafter, the initial temperature difference ΔTini is saved and the
solenoid valve 11 is closed (at step S17). Then, the routine advances to step S3 to determine whether or not the preset time t1 has elapsed. - An amount of clogging during the current trip is estimated at step S5, and then, it is determined whether or not the estimated value of the amount of clogging of the water passage during the current trip is larger than another threshold value PV2 (at step S18). The threshold value PV2 is set to a value larger than the threshold value PV1, for example, set to 60%. If the estimated value of an amount of clogging during the current trip is larger than the threshold value PV2, the control system determines a fact that the water passage is clogged abnormally with foreign material. In this case, the
solenoid valve 11 is opened (at step S19). - If the estimated value of an amount of clogging of the water passage is smaller than the threshold value PV2 so that the answer of step S18 is NO, it is determined whether or not the estimated value of an amount of clogging is larger than the threshold value PV1 (at step S20). If the estimated value of an amount of clogging of the water passage is smaller than the threshold value PV1 so that the answer of step S20 is NO, the control system determines a fact that the water passage is in a normal condition without being clogged with foreign material (at step S21). By contrast, if the estimated value of an amount of clogging of the water passage is larger than the threshold value PV1 so that the answer of step S20 is YES, the routine advances to step S22. In this case, specifically, the estimated value of an amount of clogging of the water passage is larger than the threshold value PV1 but smaller than the threshold value PV2. Consequently, the control system makes a determination of a quasi-clogging of the water passage. At step S22, optionally, a drive duty cycle of the
water pump 2 may be calculated in a manner such hat the accuracy for estimating an amount of clogging for the next trip will be improved in comparison with that during the current trip. In this case, the amount of clogging will be estimated based on the drive duty cycle of thewater pump 2 calculated at step S22. - Thus, given that the amount of clogging during the previous trip was larger than the threshold value PV1, the amount of clogging during the current trip is estimated while increasing the drive duty cycle of the
water pump 2. According to the third example shown inFig. 7 , therefore, the cooling water is allowed to flow through the water jacket smoother than the case in which the drive duty cycle of thewater pump 2 is small so that the accuracy for estimating the amount of clogging can be improved in comparison with that during the previous trip. - Referring now to
Fig. 8 , there is shown a flowchart explaining the fourth control example of the cooling control system configured to alter the drive duty cycle of thewater pump 2 depending on the vehicle speed to estimate an amount of clogging of the water passage. For example, the control example shown inFig. 8 may be applied to a hybrid vehicle in which a prime mover is comprised of an engine and a motor. Here, in the flowchart shown inFig. 8 , common numbers are allotted to the steps identical to those inFig. 1 . After making a determination of step S1, the initial temperature difference ΔTini is saved and the drive duty cycle of thewater pump 2 is adjusted according to the vehicle speed (at step S23). For example, the drive duty cycle of thewater pump 2 may be determined with reference to a preinstalled map shown inFig. 9 . Given that the vehicle speed is higher than a predetermined speed, theengine 1 will be operated frequently and heated significantly. In this case, therefore, the drive duty cycle of thewater pump 2 is increased to the maximum value. To this end, the vehicle speed can be detected by a not shown speed sensor. Then, the routine advances to step S3. - Specifically, given that the hybrid vehicle runs at a low speed, the vehicle is powered by the motor more frequently rather than powered by the engine. In this case, the drive duty cycle of the
water pump 2 can be reduced in comparison with the case in which the vehicle runs at a high speed so that the amount of clogging of the water passage can be estimated more accurately without operating theengine 1. In addition, a flow rate of the cooling water can be reduced so that theengine 1 can be prevented from being cooled excessively. By contrast, given that the hybrid vehicle runs at a high speed, the vehicle is powered by the engine more frequently rather than powered by the motor. In this case, therefore, an amount of clogging of the water passage can be estimated promptly while stopping theengine 1 by increasing the drive duty cycle of thewater pump 2. - Referring now to
Fig. 10 , there is shown a flowchart explaining the fifth control example of the cooling control system configured to alter a flow rate of the cooling water flowing through the water jacket while closing thesolenoid valve 11 depending on an estimated value of clogging of the water passage. Here, in the flowchart shown inFig. 10 , common numbers are allotted to the steps identical to those inFig. 1 . - According to the control example shown in
Fig. 10 , after step S5, it is determined whether or not an estimated value of an amount of clogging is larger than a still another threshold value PV3 (at step S24). For example, the threshold value PV3 is set to 50% that is larger than thethreshold value PV 1 but smaller than the threshold value PV2. If the estimated value of the amount of clogging is larger than the threshold value PV3 so that the answer of step S24 is YES, thesolenoid valve 11 is opened (at step S25). That is, if the estimated value of an amount of clogging is large, the cooling water flowing out of the water jacket is allowed to circulate through thebranch conduit 10. - By contrast, if the estimated value of the amount of clogging is smaller than the threshold value PV3 so that the answer of step S24 is NO, it is determined whether or not the estimated value of the amount of clogging is larger than the threshold value PV1 (at step S26). If the estimated value of the amount of clogging is smaller than the threshold value PV1 so that the answer of step S26 is NO, the routine is returned.
- By contrast, if the estimated value of the amount of clogging is larger than the threshold value PV1 so that the answer of step S26 is YES, a coefficient for correcting the drive duty cycle of the
water pump 2 is calculated to alter the drive duty cycle in accordance with the estimated value of the amount of clogging (at step S27). For example, the correction coefficient may be determined according to the estimated value of an amount of clogging with reference to a preinstalled map shown inFig. 11 . - Then, the drive duty cycle is corrected by the correction coefficient thus calculated (at step S28). Specifically, the drive duty cycle of the
water pump 2 is calculated by multiplying the current drive duty cycle by the correction coefficient, and thewater pump 2 is driven in accordance with the drive duty cycle thus corrected. In this case, if the estimated value of the amount of clogging is larger than 15% but smaller than 50%, a discharging amount of thewater pump 2 is increased in accordance with the correction coefficient determined according to the estimated value of the amount of clogging. It is to be noted that the maximum value of the drive duty cycle to be corrected by the correction coefficient is limited to a value that can drive thewater pump 2 without reducing fuel economy, on the basis of a result of experimentation or simulation. That is, given that the estimated value of the amount of clogging falls within a range between the threshold values PV1 and PV3, the fuel economy will not be reduced even if the drive duty cycle of thewater pump 2 is increased to increase a flow rate of the cooling water flowing through the water jacket. However, if the estimated value of the amount of clogging is larger than the threshold value PV3, the fuel economy may be deteriorated. In this case, thesolenoid valve 11 is opened to avoid such reduction in the fuel economy. - Thus, according to the example shown in
Fig. 10 , thesolenoid valve 11 will not be opened if the estimated value of the amount of clogging is smaller than the threshold value PV3 so that theengine 1 can be prevented from being cooled overly. By contrast, if the estimated value of the amount of clogging is larger than the threshold value PV3, thesolenoid valve 11 is opened. In this case, therefore, the drive duty cycle of thewater pump 2 does not have to be increased so that the fuel economy will not be reduced. - Here will be briefly explained a relation between the foregoing examples and the present invention. Functional means of steps S2 to S6, S8 to S13, S14 to S16, and S23 serve as the estimation means of the present invention.
Claims (5)
- A cooling control system for an engine, comprising:a cooling circuit for circulating cooling water via a water pump and the engine to cool the engine;a bypass circuit for circulating the cooling water without passing through the engine;a first temperature sensor that is disposed on the cooling circuit to detect a temperature of the cooling water flowing therethrough;a second temperature sensor that is disposed on the bypass circuit to detect a temperature of the cooling water flowing therethrough;a switching valve that is closed to reduce a flow rate of the cooling water flowing through the cooling circuit, and that is opened to increase the flow rate of the cooling water flowing through the cooling circuit; anda water passage that allows the cooling water to flow through the cooling circuit in a small amount when the switching valve is closed,characterized by:an estimation means that is configured to estimate an amount of clogging of the water passage based on a temporal change in a temperature difference between a temperature of the cooling water detected by the first temperature sensor and a temperature of the cooling water detected by the second temperature sensor, under a condition in that the engine is stopped, the switching valve is closed, and the water pump is driven.
- The cooling control system as claimed in claim 1,
wherein the estimation means includes a means configured to estimate the amount of clogging of the water passage by subtracting the temperature difference of a case in which the water pump is not driven from the temperature difference of a case in which the water pump is driven, in case an external temperature is lower than a predetermined temperature. - The cooling control system as claimed in claim 1 or 2, wherein the estimation means includes a means configured to:estimate a current amount of clogging of the water passage while reducing a drive frequency of the water pump to be less than the previous value if a current estimated value of the amount of clogging is smaller than a first threshold value, andestimate a current amount of clogging of the water passage while increasing the drive frequency of the water pump to be more than that of the previous case if the current estimated value of the amount of clogging is larger than the first threshold value.
- The cooling control system as claimed in any of claims 1 to 3,
wherein the estimation means includes a means configured to estimate the amount of clogging of the water passage by increasing the drive frequency of the water pump with an increase in a speed of a vehicle having the engine. - The cooling control system as claimed in any of claims 1 to 4, wherein the estimation means includes a means configured to:estimate the amount of clogging of the water passage while increasing the drive frequency of the water pump if the estimated value of the amount of clogging is larger than the first threshold value but smaller than a second threshold value, andopen the switching valve if the estimated value of the amount of clogging is smaller than the second threshold value.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
PCT/JP2012/065530 WO2013190619A1 (en) | 2012-06-18 | 2012-06-18 | Cooling controller for internal combustion engines |
Publications (2)
Publication Number | Publication Date |
---|---|
EP2863030A1 true EP2863030A1 (en) | 2015-04-22 |
EP2863030A4 EP2863030A4 (en) | 2016-02-24 |
Family
ID=49768250
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP12879327.0A Withdrawn EP2863030A4 (en) | 2012-06-18 | 2012-06-18 | Cooling controller for internal combustion engines |
Country Status (5)
Country | Link |
---|---|
US (1) | US20150240702A1 (en) |
EP (1) | EP2863030A4 (en) |
JP (1) | JP5910743B2 (en) |
CN (1) | CN104379894A (en) |
WO (1) | WO2013190619A1 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP2993326A4 (en) * | 2013-04-30 | 2016-12-28 | Toyota Motor Co Ltd | Cooling-water control device |
US9903260B2 (en) | 2014-12-01 | 2018-02-27 | Toyota Jidosha Kabushiki Kaisha | Apparatus and method for determining pore clogging in engine cooling system |
Families Citing this family (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP6079764B2 (en) * | 2014-12-10 | 2017-02-15 | トヨタ自動車株式会社 | Internal combustion engine cooling system and control method thereof |
JP6079766B2 (en) * | 2014-12-12 | 2017-02-15 | トヨタ自動車株式会社 | Engine cooling system and operation method thereof |
JP6241435B2 (en) * | 2015-03-03 | 2017-12-06 | トヨタ自動車株式会社 | Internal combustion engine temperature control device |
JP6160646B2 (en) | 2015-03-27 | 2017-07-12 | トヨタ自動車株式会社 | Engine cooling system |
JP6374342B2 (en) * | 2015-04-08 | 2018-08-15 | トヨタ自動車株式会社 | Engine cooling system |
JP6265195B2 (en) * | 2015-10-01 | 2018-01-24 | トヨタ自動車株式会社 | Control device for internal combustion engine |
CN106089395B (en) | 2016-07-26 | 2018-11-02 | 广州汽车集团股份有限公司 | Engine water temperature control method and device |
JP6627826B2 (en) * | 2017-07-10 | 2020-01-08 | トヨタ自動車株式会社 | Control unit for heat exchange system |
JP6610622B2 (en) * | 2017-07-10 | 2019-11-27 | トヨタ自動車株式会社 | Control device for heat exchange system |
JP7076396B2 (en) * | 2019-03-27 | 2022-05-27 | 日立建機株式会社 | Work machine |
CN113109390B (en) * | 2021-05-17 | 2023-09-12 | 西安热工研究院有限公司 | Method for evaluating chemical cleaning effect of turbine generator stator cooling water |
Family Cites Families (19)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2712711B2 (en) * | 1990-02-16 | 1998-02-16 | 株式会社デンソー | Method and apparatus for cooling internal combustion engine |
US5404842A (en) * | 1992-12-15 | 1995-04-11 | Nippon Soken, Inc. | Internal combustion engine cooling apparatus |
US5458096A (en) * | 1994-09-14 | 1995-10-17 | Hollis; Thomas J. | Hydraulically operated electronic engine temperature control valve |
JP4045894B2 (en) * | 2002-08-19 | 2008-02-13 | 株式会社デンソー | Engine and fuel cell cooling system |
JP3932035B2 (en) * | 2002-08-21 | 2007-06-20 | 株式会社デンソー | Abnormality diagnosis device for cooling system of internal combustion engine |
US7182048B2 (en) * | 2002-10-02 | 2007-02-27 | Denso Corporation | Internal combustion engine cooling system |
JP4172269B2 (en) * | 2002-12-27 | 2008-10-29 | トヨタ自動車株式会社 | Internal combustion engine equipped with a heat storage device |
JP2007046469A (en) * | 2005-08-05 | 2007-02-22 | Denso Corp | Exhaust heat recovery device |
JP4679485B2 (en) * | 2006-07-10 | 2011-04-27 | カルソニックカンセイ株式会社 | EGR device |
US7581517B2 (en) * | 2007-06-07 | 2009-09-01 | Brown Myron L | Automatic by-pass safety cooling system for fire pump engines |
JP2008308124A (en) * | 2007-06-18 | 2008-12-25 | Toyota Motor Corp | Hybrid car |
JP4306782B2 (en) * | 2007-11-21 | 2009-08-05 | トヨタ自動車株式会社 | Vehicle cooling control apparatus and cooling control method |
JP4456162B2 (en) * | 2008-04-11 | 2010-04-28 | 株式会社山田製作所 | Engine cooling system |
JP5175764B2 (en) * | 2009-02-19 | 2013-04-03 | 日立オートモティブシステムズ株式会社 | Cooling device for internal combustion engine |
WO2011042942A1 (en) * | 2009-10-05 | 2011-04-14 | トヨタ自動車 株式会社 | Cooling device for vehicle |
JP2011099400A (en) * | 2009-11-06 | 2011-05-19 | Toyota Motor Corp | Cooling device for vehicle |
JP2011111962A (en) * | 2009-11-26 | 2011-06-09 | Aisin Seiki Co Ltd | Internal combustion engine cooling system |
JP5526982B2 (en) * | 2010-04-27 | 2014-06-18 | 株式会社デンソー | Internal combustion engine cooling device |
JP5569350B2 (en) * | 2010-11-11 | 2014-08-13 | トヨタ自動車株式会社 | Switching valve failure judgment device |
-
2012
- 2012-06-18 JP JP2014521109A patent/JP5910743B2/en not_active Expired - Fee Related
- 2012-06-18 US US14/408,328 patent/US20150240702A1/en not_active Abandoned
- 2012-06-18 CN CN201280074088.0A patent/CN104379894A/en active Pending
- 2012-06-18 WO PCT/JP2012/065530 patent/WO2013190619A1/en active Application Filing
- 2012-06-18 EP EP12879327.0A patent/EP2863030A4/en not_active Withdrawn
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP2993326A4 (en) * | 2013-04-30 | 2016-12-28 | Toyota Motor Co Ltd | Cooling-water control device |
US9903260B2 (en) | 2014-12-01 | 2018-02-27 | Toyota Jidosha Kabushiki Kaisha | Apparatus and method for determining pore clogging in engine cooling system |
Also Published As
Publication number | Publication date |
---|---|
EP2863030A4 (en) | 2016-02-24 |
WO2013190619A1 (en) | 2013-12-27 |
CN104379894A (en) | 2015-02-25 |
JP5910743B2 (en) | 2016-04-27 |
US20150240702A1 (en) | 2015-08-27 |
JPWO2013190619A1 (en) | 2016-02-08 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
EP2863030A1 (en) | Cooling controller for internal combustion engines | |
US9324199B2 (en) | Method and system for controlling an engine cooling system | |
US9341105B2 (en) | Engine cooling system control | |
US9217689B2 (en) | Engine cooling system control | |
US9022647B2 (en) | Engine cooling system control | |
JP6264443B2 (en) | COOLING SYSTEM CONTROL DEVICE AND COOLING SYSTEM CONTROL METHOD | |
US9677458B2 (en) | Temperature control device for internal combustion engine | |
CN102482982B (en) | Control device for variable water pump | |
JP4755687B2 (en) | Method for adjusting the temperature of an electromechanical component and apparatus for carrying out the method | |
US9874134B2 (en) | Cooling water control apparatus | |
US20140069522A1 (en) | Fluid control system | |
US10190479B2 (en) | Cooling system with a coolant pump for an internal combustion engine | |
US20170016380A1 (en) | Control Device for Internal Combustion Engine and Control Method for Cooling Device | |
US8978599B2 (en) | Cooling apparatus of internal combustion engine for vehicle | |
KR102030880B1 (en) | Fluid supply device | |
US20220063394A1 (en) | Cooling apparatus for hybrid vehicle | |
JP2009197616A (en) | Cooling system, cooling control device, and flow rate control method | |
JP3957531B2 (en) | Engine cooling system | |
JP2006037883A (en) | Cooling system of internal combustion engine | |
JP2009046077A (en) | Abnormality determination device for electric water pump | |
JP2013092131A (en) | Engine cooling device | |
KR101039525B1 (en) | Oil heating apparatus | |
JP2008175104A (en) | Cooling device for vehicular internal combustion engine |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
17P | Request for examination filed |
Effective date: 20141212 |
|
AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR |
|
AX | Request for extension of the european patent |
Extension state: BA ME |
|
DAX | Request for extension of the european patent (deleted) | ||
RA4 | Supplementary search report drawn up and despatched (corrected) |
Effective date: 20160126 |
|
RIC1 | Information provided on ipc code assigned before grant |
Ipc: F01P 7/14 20060101ALI20160120BHEP Ipc: F01P 7/16 20060101AFI20160120BHEP Ipc: F01P 7/04 20060101ALI20160120BHEP Ipc: F01P 11/14 20060101ALI20160120BHEP |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN |
|
18D | Application deemed to be withdrawn |
Effective date: 20160823 |