EP3112630A1

EP3112630A1 - Vehicle cooling system

Info

Publication number: EP3112630A1
Application number: EP16177126.6A
Authority: EP
Inventors: Alessandro BENEVELLI; Riccardo Morselli
Original assignee: CNH Industrial Italia SpA
Current assignee: CNH Industrial Italia SpA
Priority date: 2015-07-03
Filing date: 2016-06-30
Publication date: 2017-01-04
Also published as: ITUB20151905A1

Abstract

A coolant system for a vehicle (10) with an internal combustion (IC) engine (12) includes a first coolant circuit (18) and air to liquid heat exchanger (14) for the engine (12) and a second coolant circuit (24) for a plurality of vehicle systems such as oil cooler, fuel cooler and charge air cooler (36, 48, 60). Additionally, an HVAC compressor (72) may be cooled. The control through the second cooling circuit (24) is maintained by valves (44, 56, 68, 78) for each heat exchanger (28, 30, 32, 34) and appropriate sensors (42, 54, 66, 74), along with the second coolant circuit pump output, and fan (86) output to achieve efficient heat transfer enabling a compact engine package. An alternate cooling system (90) includes a second heat exchanger (92) that provides a circuit for higher temperature operating heat exchangers (102, 104) and an additional circuit for a lower temperature operating heat exchanger (116).

Description

BACKGROUND OF THE INVENTION

The present invention relates to vehicle cooling systems particularly, to cooling systems for such vehicles that incorporate internal combustion (IC) engines that may be used in tractors.
Throughout the history of internal combustion engine development for powering vehicles, there has existed a need for dispersing the waste heat generated by the inherent thermal efficiency of the combustion process and heat generating vehicle components. Although the efficiency of the compression ignition or diesel engine is significantly greater than the spark ignition gasoline fueled engine, it still requires heat exchangers to carry away the excess heat.
The heat exchangers for engines may be grouped into a primary exchanger for the coolant of the engine block and head. This requires a significant flow and significant area of the heat exchanger which is usually an air to liquid heat exchanger, or radiator. Engines additionally are being called upon to provide cooling for auxiliary vehicle components and systems, both from the standpoint of increasing overall efficiency and from dispersing waste heat. A charge air cooler receives the output from a compressor to cool and thus increase the density of the charge air mixture to the engine for increased power and efficiency. Various other components and systems in the vehicle need cooling such as the fuel system, vehicle hydraulic oil system and condenser for a heating and air conditioning system (HVAC). In many instances, the engines have used a common coolant circuit for a primary engine heat exchanger and for the auxiliary component and system heat exchangers. This has resulted in less than an optimal heat transfer for the auxiliary components and systems since the operating temperatures and differential temperatures for the primary engine are higher than those for the components.
In some cases, it has been proposed to provide a separate cooling system for selected components or systems. One such component may be an air to air cooler for the engine charge air. While this permits a lower charge air temperature to the engine, it does so at the expense of a greatly increased engine envelope. Other vehicle systems requiring cooling are a hydraulic system or a condenser for an air conditioning system. While an increased engine envelope may be tolerated for an over the road transport vehicle, it presents a problem in the agricultural field where the power unit is constrained to be as compact in volume as possible and is generally positioned well within the confines of the agricultural vehicle.
What is needed in the art, therefore, is a vehicle cooling system that allows its heat exchangers to operate under efficient conditions and enables a compact overall engine envelope.

SUMMARY OF THE INVENTION

The present invention provides a dual loop cooling system enabling efficient operation of engine and vehicle components and efficient arrangement of such components.
The invention, in one form, is directed to a cooling system for a vehicle having an air breathing, fuel consuming, liquid cooled internal combustion (IC) engine which has a plurality of heat generating auxiliary systems. The cooling system includes a first air to liquid heat exchanger, a first pump for circulating liquid and a first fluid circuit connecting the first air to liquid heat exchanger to the first pump and the IC engine for cooling the IC engine. A second air to liquid heat exchanger is provided for a plurality of heat generating auxiliary systems. A second pump is provided for circulating liquid. A plurality of liquid to one of air and liquid heat exchangers are provided along with a second fluid circuit connecting the second air to liquid heat exchanger to the second pump and in parallel to the plurality of liquid to one of air and liquid heat exchangers. Valves are provided for each of the liquid to one of air and liquid heat exchangers of the auxiliary systems for controlling the flow therethrough and a controller is provided for independently controlling the valves.
In another form, the invention is a vehicle and an internal combustion engine including an engine block with a plurality of combustion cylinders and fuel pump for supplying fuel to the combustion cylinders. The engine includes a first air to liquid heat exchanger, a first pump for circulating liquid and a first fluid circuit for connecting the first air to liquid heat exchanger to the pump and the IC engine for cooling the IC engine. A second air to liquid heat exchanger is provided for a plurality of heat generating auxiliary systems. A second pump is provided for circulating liquid to the plurality of liquid to one of air and liquid heat exchangers. A second fluid circuit is provided for connecting the second air to liquid heat exchanger to the second pump and in parallel to the plurality of liquid to one of air and liquid heat exchangers. Valves are provided for each liquid to one of air and liquid heat exchangers for the auxiliary systems to control the flow therethrough and a controller is provided for independently controlling the valves.
In yet another form, the invention is a cooling system for a vehicle having an air breathing fuel consuming internal combustion engines including a plurality of heat generating auxiliary systems at a first level and another heat generating system at a lower operating temperature level. A first air to liquid heat exchanger and pump for circulating liquid supplies coolant to the IC engine for coolant purposes. A second pump is provided for circulating liquid through a second fluid circuit connecting to a plurality of liquid to liquid heat exchangers. A second air to liquid heat exchanger includes a first circuit for cooling a portion of the coolers operating at a higher temperature and a second cooling circuit for supplying one of the heat generating auxiliary systems at a lower temperature.
An advantage of the present invention is that coolant flow through the circuit cooling auxiliary systems may be balanced to provide the most efficient heat transfer through the system.
Another advantage is that the heat exchangers for auxiliary systems may be contiguous to and compactly arranged on the frame of an IC engine.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings, wherein:

Fig. 1 is a schematic drawing of an engine, auxiliary systems and a cooling arrangement for the auxiliary systems that embodies the present invention;
Fig. 2 is a perspective view of an engine showing the spatial location of auxiliary systems for the engine and cooling system of Fig. 1;
Fig. 3 is a schematic drawing of an engine, auxiliary systems and a cooling arrangement for the auxiliary systems that embodies an alternate form of the present invention; and,
Fig. 4 is a perspective view of a heat exchanger incorporated in the engine of Fig. 3.

Corresponding reference characters indicate corresponding parts throughout the several views. The exemplification set out herein illustrates one embodiment of the invention, in one form, and such exemplification is not to be construed as limiting the scope of the invention in any manner.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings, and more particularly to Fig. 1, there is shown a schematic arrangement of a vehicle 10 and its auxiliary systems. The vehicle 10 may be an agricultural or work machine. The vehicle 10 includes an engine 12 that is air consuming and fuel burning to produce a useful rotary work output to provide prime motive power and power auxiliary equipment. The preferred form for an engine utilized in the agricultural and work machine environment is a multi-cylinder compression ignition or diesel engine in which the heat of compression of intake air, combined with injection of fuel, produces compression ignition according to the diesel cycle. This type of engine is preferred because of its inherent durability and its efficiency, particularly at part power conditions. Although the system is illustrated in connection with such an engine, it should be noted that other engine cycles may utilize the invention with similar advantages.
Engine 12 includes a first air to liquid heat exchanger 14 in a coolant circuit 18 having a coolant pump 16 for pressurizing flow of liquid coolant through internal passages and engine 12 for dissipating heat to the ambient air through air flowing through heat exchanger 14 which is sometimes referred to as a radiator. An appropriate fan (not shown) is provided for directing flow through the heat exchanger 14 to provide cooling to the engine. The heat exchanger 14 is designed to dissipate heat from an engine operating condition that is approximately around the temperature of the boiling point of water and is usually higher than that value for efficient heat transfer.
In accordance with the present invention, a second heat exchange system is provided for engine components to be operated at a lower operating temperature so as to more closely match the anticipated lower heat generating properties of the auxiliary systems. The second heat exchange circuit includes a second air to liquid heat exchanger 20 which is positioned in line with and in front of the heat exchanger 14. A second pump 22 is provided in a second liquid coolant circuit 24 and provides coolant flow through a second pump outlet line 26. A series of auxiliary heat exchangers are connected in parallel with the second pump output line 26 as described below.
A liquid to liquid oil cooler 28 is one such cooler. Additionally, a liquid to liquid fuel cooler 30 is provided, as well as a liquid to air charge cooler 32. Finally, a liquid to liquid and air conditioning (HVAC) condenser 34 is provided.
Turning to the individual components, an oil pump 36 receives lubricant from a sump indicated at 38 and delivers it to an oil feed circuit 40 which connects with tubing, conduits and actuators of an auxiliary hydraulic system 43. An oil temperature sensor 42 is provided in the oil feed circuit 40, usually by the outlet port of the oil cooler 28. The flow through the oil cooler 28 is controlled by a control valve 44 allowing flow through the oil cooler flow circuit 46 from the coolant line 26 for the second pump 22.
A fuel pump 48 receives fuel from a fuel supply 50 (not shown) and delivers it to a fuel feed circuit 52. The fuel feed circuit 52 may take many forms having as an objective the delivery of the correct metered amount of fuel at the correct timing and appropriate delivery pressure for efficient combustion. Details of the fuel feed circuit 52 are not discussed to enable a clearer understanding of the present invention. The fuel feed circuit 52 includes a fuel temperature sensor 54 which provides a signal proportional to the temperature of the fuel. A fuel coolant control valve 56 varies the flow through a fuel cooler control circuit 58 which connects to the output line 26 of pump 22 in parallel with the other heat exchangers.
A compressor 60 is provided to pre-pressurize combustion air delivered to engine 12 from an intake system 62 through a charge air intake system 64. The compressor 60 may take any one of a number of forms and usually the compressor is driven a turbine which receives its energy from the exhaust gases discharged from engine 12. The charge air intake system 64 includes a temperature sensor 66 which generates a signal proportional to the air temperature downstream of the charge air cooler 32. A charge air coolant control valve 68 varies the flow through a charge air cooler liquid control circuit 70.
The auxiliary component that may or may not be present in the vehicle 10 would be the condenser 34 for the HVAC system. An HVAC compressor 72 is interposed in an HVAC coolant circuit and has an HVAC pressure sensor 74 at the output of compressor 72. The HVAC coolant circuit 76 passes through cooler 34 to condense the liquid or refrigerant to provide coolant for operator comfort. A condenser coolant control valve 78 varies the flow through a condenser cooler control circuit 80. The coolant control circuit 80, along with circuits 70, 58 and 46 all connect to a second liquid coolant return line 82 in parallel, which then connects to the second air to liquid heat exchanger 20 for dissipating the heat generated in the engine auxiliary systems.
The control of the valves 44, 56, 68 and 78 is in response to sensor inputs from sensors 42, 54, 66 and 74 that are all fed to an engine control unit 84 (ECU). ECU 84 may be provided as the master control for the propulsion system 10 in which it controls the fuel flow, manages the charge air temperature and coordinates the cooling of the auxiliary systems through the second control circuit. For the sake of focusing on the invention, the schematic representation of interconnections between the ECU 84 and the various valves and sensors are not illustrated. However, it should be understood to those skilled in the art that appropriate interconnections may be provided between the engine components. A cooling fan, indicated at 86, is interconnected with, and controlled by, ECU 84 through line 88.
In operation, the first coolant circuit deals with the cooling of the primary parts of the engine. As stated previously, this involves a far greater generation of heat than those of auxiliary systems and for that purpose has a larger heat exchanger or radiator than for the auxiliary systems. The flow through the individual heat exchangers is controlled by the valves through the ECU to maintain appropriate temperatures. Furthermore, the flow through the second system may be varied by the output of the pump 22. This may be accomplished by utilizing an electric pump whose rpm and therefor output is varied by control inputs from the ECU 84. In addition, the flow of the cooling fan 86 is controlled by ECU 84 to vary the heat taken out of the system by first and second heat exchangers 14, 20, respectively.
In addition, the flow through the second system may be accomplished by a combination of flow permitted by the valves 36, 48, 68, 78, by the pump 22 output and fan 86 output to provide the appropriate temperature gradient across the heat exchangers and thus have a most efficient heat transfer. Although the heat exchangers for oil fuel and charge air are operating constantly, the condenser for the HVAC system operates only when that system is working. In that case, when the HVAC system is not working, the valve 78 is closed thus requiring a rebalancing of the flow through the parallel circuits through the heat exchangers. The ECU 84 enables the independent control of flow through the plurality of component heat exchangers to achieve the most efficient heat transfer.
The arrangement of the system in Fig. 1 enables a highly compact engine propulsion system 10 which is illustrated in Fig. 2. Referring to Fig. 2, the engine 12 has the first heat exchanger 14 adjacent one end and the second heat exchanger 20 in line with and immediately in front of it. The pump 22 for the second coolant circuit is a small one contiguous to and on the side of the engine. The oil cooler 28 is a compact module also contiguous to the side of the engine. The fuel cooler 30 is also contiguous to the engine 12 and is in line with the fuel system. The charge air cooler 32 is included in the charge air circuit and provides a significant reduction in volume compared to prior air to air charge air coolers. Finally, the liquid to liquid condenser cooler 34 is contiguous to and mounted on the engine 12 and is close to the HVAC compressor 70, normally mounted on and driven mechanically by engine 12. This minimizes the volume of coolant in the HVAC system. All these coolers and their positions on the engine enable a much denser package for the engine propulsion system 10. This enables a more efficient vehicle 10, especially as a tractor, combine or other work machine.
The cooling system arrangement 90, shown in Figs. 3 and 4, provides the same benefits realized by the cooling system of 1 and 2. The arrangement in system 90 further capitalizes on the variation in operating temperatures of the heat generating components of the system. The operating system components, as they relate to the primary several components of the propulsion system shown in Figs. 1 and 2, are identical and these will be given identical references. Thus, engine 12 generates heat in operation and the line 18 and pump 16 circulate the coolant through radiator 13. A fan 20 is appropriately controlled to provide the coolant needs of engine 12.
As a part of the cooling system 90, there is a second heat exchanger or radiator 92 that receives coolant from a circulating pump 94 via a line 96. A first outlet line 98 connects to heat exchange devices including a liquid to liquid charge air cooler 102 and a liquid to liquid oil cooler 104 through conduit 100. Return flow from coolers 102 and 104 passes via lines 106, 108 to a return line 110 via a four way junction 112. Return line 110 feeds the inlet of pump 94.
The charge air cooler 102 and oil cooler 104 have operating temperatures that are in equivalent ranges and can be balanced by a common radiator. However the liquid to liquid AC condenser 116 efficiently operates at a lower temperature. For this purpose a secondary coolant line 114 leads from heat exchanger 92 to the liquid to liquid A/C condenser 116 and from there via return line 118 to four way junction 112 and thence to the inlet of pump 94. As illustrated, the flow of coolant through charge air cooler 102 and oil cooler 104 is respectively controlled by valves 122 and 120. The flow of coolant through the A/C condenser is controlled by valve 124. Valves 120, 122 and 124 are appropriately controlled, preferably through an ECU, in response to selected temperature parameters to maintain the optimum cooling flow according to the needs of the cooler. The details of the control interconnection are not shown to enable a clearer understanding of the present invention.
The primary and secondary flows through second heat exchanger 92 are illustrated in Fig. 4 which shows a housing 126 for the heat exchange medium 130 and 132. The heat exchange housing 126 has brackets 128 to enable mounting in a vehicle. The heat exchange medium 130 and 132 consists of tube and fin arrangements in which the liquid coolant is passed through a multiplicity of tubes and air is passed over fins connected to the tubes in heat exchange relationship in a u-shaped pattern to draw heat from the coolant mediums 130 and 132. Cooling medium 130 is fed with liquid coolant via inlet 134 which is connected to line 96. Coolant medium 130 has a first outlet 136 connected to line 98 extending to the charge air cooler and oil coolers. Coolant medium 132 also consists of tube and fins but is fed with an input liquid flow via an orifice 138 between medium 130 and 132. The medium 132 has an outlet connection 140 to line 114 which supplies coolant to the A/C condenser. Heat exchange medium 132 receives an input flow at the lowest temperature of the coolant medium 130, therefore cooling it to a significantly lower temperature through coolant medium 132. As a result, the second heat exchanger 92, within an envelope no larger than the overall envelope for the secondary heat exchanger of Figs. 1 and 2, provides a coolant level that is much more appropriate for the needs of the A/C condenser. As a result, the flow balance between the various components can be more easily achieved without the need for additional variable geometry in the liquid flow system.
While the system in Figs. 3 and 4 shows a fixed orifice 138 between coolant medium 130 and 132 it should be understood those skilled in the art that a variable orifice may be provided therebetween to perform functions similar to the control valve 124.
In both the embodiments shown in Figs. 1 and 2 and 3 and 4 the dissipation of the heat generated may be achieved in the compact fashion enabling an overall engine package size to be like that shown in Fig. 2. This makes the cooling system particularly applicable to work machines and agriculture equipment in particular where the primary power unit is surrounded by other components of the agricultural machine.
While this invention has been described with respect to at least one embodiment, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.

Claims

A cooling system for a vehicle having an air breathing fuel consuming internal combustion (IC) engine, having a plurality of heat generating auxiliary systems (36, 48, 60, 72), said cooling system comprising:
a first air to liquid heat exchanger (14);

a first pump (16) for circulating liquid;

a first fluid circuit (18) connecting the first air to liquid heat exchanger (14) to said pump (16) and IC engine (12) for cooling said IC engine (12);

a second air to liquid heat exchanger (20) for the plurality of heat generating auxiliary systems (36, 48, 60, 72);

a second pump (22) for circulating liquid;

a plurality of liquid to one of air and liquid heat exchangers (28, 30, 32, 34);

a second fluid circuit (24) connecting the second air to liquid heat exchanger (20) to said second pump (22) and in parallel flow relationship to said plurality of liquid to one of air and liquid heat exchangers (28, 30, 32, 34);

said system characterized by:
a valve (44, 56, 68, 78) for at least one of said liquid to one of air and liquid heat exchangers (28, 30, 32, 34) of the auxiliary systems (36, 48, 60, 72) controlling the liquid flow therethrough and a controller (84) for independently controlling said valve (44, 56, 68, 78).
The cooling system as claimed in claim 1, wherein said second pump (22) has a variable speed.
The cooling system as claimed in claim 2, wherein said second pump (22) is electrically driven.
The cooling system as claimed in any one of the previous claims further comprising a fan (86) operated by said controller (84) for cooling said second air to liquid heat exchanger (20), in which the flow control through said second fluid circuit (24) is made by a combination of said second pump (22) output and valve (44, 56, 68, 78) control and air flow of said fan (86) through said second air to liquid heat exchanger (20).
The cooling system as claimed in any of the proceeding claims, further comprising heat generating auxiliary systems having at least one system selected from the group having a charge air compressor (60) cooled by a liquid to air heat exchanger (32) in said second fluid circuit (24), an oil pump (36) cooled by a liquid to liquid heat exchanger (28) in said second fluid circuit (24), a fuel system including a fuel pump (48) cooled by a liquid to liquid heat exchanger (30) in said second fluid circuit (24), and a condenser for an air conditioning system including a compressor (72) cooled by a liquid to liquid heat exchanger (34) in said second fluid circuit (24).
The cooling system as claimed in any of the preceding claims in combination with a vehicle and an internal combustion (IC) engine (12) comprising:
an engine block including a plurality of combustion cylinders; and,

wherein said liquid to one of air and liquid heat exchangers (28, 30, 32, 34) are contiguous to and on the engine block.
The cooling system of claim 6, further including a controller (84) for controlling the flow through said auxiliary heat exchangers (28, 30, 32, 34) to maintain temperatures of said auxiliary heat generating components (36, 48, 60, 72).
The cooling system as claimed in claim 7 further comprising temperature sensors (42, 54, 66) for generating a signal in response to the temperature output of at least a portion of said plurality of heat exchangers (28, 30, 32, 34) and supplying said signal to said controller (84) for control of the temperature in said second system (24).
A cooling system as claimed in claim 1 wherein said second air to liquid heat exchanger (92) for cooling the flow through the fluid circuit (96, 98, 100 114, 110) cools a portion of the liquid to liquid heat exchangers (102, 104) to a first temperature level and cools the heat exchanger (116) having a lower operating temperature to a lower temperature level.
The cooling system as claimed in claim 9 wherein said second heat exchanger (92) has first and second coolant mediums (130, 132) the first of which provides coolant for higher temperature operating coolers (102, 104) and the second cooling system medium (132) receives cooled flow from coolant medium (132) and provides it to the said lower operating temperature heat exchanger (116).
The cooling system as claimed in claim 10 wherein said second air to liquid heat exchanger (92) includes a first coolant medium (130) arranged in an orientation where the inlet is at a bottom of the second air to liquid heat exchanger and the outlet is at the bottom and said second heat exchange medium (132) is side by side with the entry to the second heat exchange medium (132) at the bottom and the flow traveling in a u-shaped pattern to an outlet (140) at the bottom of the second air to liquid heat exchanger (92).
The cooling system as claimed in claims 10 to 11 wherein an orifice (138) is provided between said first coolant medium (130) and said second coolant medium (132).
The cooling system as claimed in claims 10 to 12 wherein the heat exchanger having a lower operating temperature is an A/C condenser (116).