WO2018225305A1

WO2018225305A1 - Engine cooling system

Info

Publication number: WO2018225305A1
Application number: PCT/JP2018/006237
Authority: WO
Inventors: 石田　哲朗; 井上　隆; 増次足立
Original assignee: 三菱自動車工業株式会社
Priority date: 2017-06-05
Filing date: 2018-02-21
Publication date: 2018-12-13
Also published as: EP3636893A4; EP3636893A1; JPWO2018225305A1

Abstract

This engine cooling system suppresses supply of a refrigerant to a radiator (20), sub-heat exchangers (30, 40, 50), and an area (10) to be cooled, said area being a part of an engine (1), in the cases where the temperature of the refrigerant is lower than a first predetermined value (T1), and in the cases where the temperature of the refrigerant becomes equal to the first predetermined value (T1) or higher, the engine cooling system stops suppressing the supply of the refrigerant to the area (10). Furthermore, in the cases where the temperature of the refrigerant is equal to the first predetermined value (T1) or higher but lower than a second predetermined value (T2), the engine cooling system stops supplying the refrigerant to the radiator (20), and supplies the refrigerant to the sub-heat exchangers (30, 40, 50), and in the cases where the temperature is equal to or higher than the second predetermined value (T2), the engine cooling system supplies the refrigerant to the radiator (20).

Description

Engine cooling system

The present invention relates to an engine cooling system including a liquid cooling type cooling device that cools a cooling target portion of an engine with a refrigerant.

Vehicles equipped with various engines such as gasoline engines and diesel engines are provided with a water-cooled cooling device that cools the engine body around the cylinder by circulating cooling water as a refrigerant.

In a water-cooled cooling device for cooling an engine body, cooling water is supplied to a space such as a water jacket provided in a cylinder block by a pump device called a water pump, and fuel in the cylinder is supplied by the cooling water. Excessive temperature rise of the engine body due to combustion is suppressed. The cooling water is cooled by a refrigerant cooling heat exchanger such as a radiator, and then circulates again to the engine body via the pump device.

In this type of water-cooled cooling device, control is performed to promote engine warm-up by switching the flow path of the cooling water in accordance with the temperature of the cooling water (for example, see Patent Document 1 below).

Japanese Patent Laying-Open No. 2015-175296

The technique described in Patent Document 1 includes an exhaust gas recirculation device that recirculates a part of exhaust gas as exhaust gas recirculation gas to the intake air, and cools the exhaust gas recirculation gas with cooling water for cooling the engine body. A water-cooled exhaust gas recirculation cooler is provided. A sub-radiator, which is a refrigerant cooling heat exchanger different from the radiator, is arranged in front of the radiator arranged to lower the temperature of the cooling water.

And according to the temperature of the cooling water on the downstream side of the exhaust gas recirculation gas cooler, for example, when the temperature of the cooling water is lower than a threshold value, the control is performed so that the thermostat is closed and the cooling water is not circulated through the engine. When the temperature of the cooling water is above a threshold value, the thermostat is opened so that the cooling water is circulated through the engine and only the radiator is used to cool the cooling water, and the temperature of the cooling water is higher. In the open state of the thermostat, the control is selectively performed using only the sub-radiator disposed in front of the radiator.

However, in the conventional engine cooling system, when it is desired to accelerate the temperature rise, for example, when the engine is warming up, the temperature of the cooling water is changed from a state where the circulation of the cooling water to the engine is restricted by closing the thermostat. When the thermostat opens and the thermostat opens, there may occur a situation in which the cooling water that has passed through the radiator flows into the engine all at once. For this reason, there is a problem that the coolant having a relatively low temperature that has passed through the radiator flows into the engine even if the temperature of the engine is raised at an early stage, preventing the early temperature rise.

Therefore, the present invention is to avoid the hindrance to the temperature rise caused by the low temperature refrigerant flowing into the engine when it is desired to promote the temperature rise during the warm-up operation of the engine.

In order to solve the above problems, the present invention provides a pump device that sends out a refrigerant, an engine cooling target that is cooled by heat exchange with the refrigerant, a radiator that cools the refrigerant, the pump device, and the A refrigerant circulation circuit for connecting the object to be cooled and the radiator to circulate the refrigerant; a sub refrigerant circulation circuit including a sub heat exchanger to which the refrigerant is supplied and having a heat exchange performance lower than that of the radiator; and the object to be cooled Refrigerant temperature acquisition means for acquiring information correlated with the temperature of the refrigerant in the case where the temperature of the refrigerant is less than a first predetermined value during warm-up operation, to the radiator and the sub heat exchanger When the supply of the refrigerant is suppressed, and the temperature of the refrigerant rises and the temperature of the refrigerant becomes equal to or higher than a first predetermined value, the supply of the refrigerant is canceled and the suppression is suppressed. When the temperature of the refrigerant is less than a second predetermined value set to a value higher than the first predetermined value, the supply of the refrigerant to the radiator is stopped and the sub heat exchanger An engine cooling system is used that supplies refrigerant and supplies the refrigerant to the radiator when the temperature of the refrigerant is equal to or higher than the second predetermined value.

Here, the sub heat exchanger can adopt a configuration in which the amount of refrigerant flowing out from the sub heat exchanger per unit time is smaller than the radiator.

In each of these aspects, the sub heat exchanger employs a configuration in which the temperature of the refrigerant after being dissipated through the sub heat exchanger is higher than the temperature of the refrigerant after passing through the radiator. can do.

In each of these aspects, when the temperature of the refrigerant is lower than the first predetermined value during the warm-up operation, supply of the refrigerant to the radiator and the sub heat exchanger is stopped, and the temperature of the refrigerant is A configuration may be adopted in which supply of the refrigerant to the sub heat exchanger is started when the temperature of the refrigerant rises and becomes equal to or higher than the first predetermined value.

Here, the sub refrigerant circulation circuit includes, as the sub heat exchanger, a first type sub heat exchanger that raises the temperature of the refrigerant and a second type sub heat exchanger that lowers the temperature of the refrigerant, When supplying the refrigerant to the exchanger, if the temperature of the refrigerant is less than a third predetermined value set between the first predetermined value and the second predetermined value, the first type sub heat exchanger The refrigerant is supplied to the second-type sub heat exchanger, the supply of the refrigerant to the second-type sub heat exchanger is stopped, and when the refrigerant temperature is equal to or higher than the third predetermined value, the second-type sub-heat exchanger is supplied. The structure which supplies the refrigerant | coolant of this can be employ | adopted.

Further, the sub refrigerant circulation circuit includes a small capacity sub heat exchanger having a relatively low cooling performance and a large capacity sub heat exchanger having a relatively high cooling performance as the sub heat exchanger for lowering the temperature of the refrigerant. When the refrigerant is supplied to the sub heat exchanger that lowers the temperature of the refrigerant, the temperature of the refrigerant is less than a fourth predetermined value set between the first predetermined value and the second predetermined value In the case where the refrigerant is supplied to the small-capacity sub heat exchanger and the supply of the refrigerant to the large-capacity sub heat exchanger is stopped, and the temperature of the refrigerant is equal to or higher than the fourth predetermined value. A configuration for supplying the refrigerant to the large-capacity sub heat exchanger can be adopted.

In each of these aspects, the engine includes an exhaust gas recirculation device that recirculates a part of the exhaust gas to the intake air as exhaust gas recirculation gas, and the exhaust gas recirculation device cools the exhaust gas recirculation gas with the refrigerant. An exhaust gas recirculation cooler of the type can be provided, and the sub heat exchanger can employ a configuration including the exhaust gas recirculation gas cooler.

In each of these aspects, the sub heat exchanger can employ a configuration including a heater core provided in an air conditioner of a vehicle on which the engine is mounted.

In each of these aspects, the sub heat exchanger includes a liquid-cooled engine oil cooler that cools the engine lubricating oil with the refrigerant, a liquid-cooled intercooler that cools intake air with the refrigerant, and an engine driving force. It is possible to adopt a configuration including a single element or a plurality of elements selected from a liquid-cooled transmission oil cooler that cools the lubricating oil of the transmission to which the above-mentioned transmission is performed with the refrigerant.

In the present invention, when it is desired to increase the temperature, for example, when the engine is warming up, before the refrigerant that has passed through the radiator is supplied to the engine, the refrigerant common to the radiator is supplied to increase the temperature of the refrigerant or the radiator. Since the refrigerant that has passed through the sub heat exchanger with lower cooling performance is supplied, when the temperature rise is to be promoted, such as during warm-up of the engine, the temperature rises due to the low-temperature refrigerant flowing into the engine. The temperature hindrance can be avoided.

It is a mimetic diagram showing a refrigerant circulation circuit of an embodiment of this invention. It is a graph which shows the temperature change of a refrigerant | coolant. It is a graph which shows control of this invention.

An engine cooling system according to an embodiment of the present invention will be described with reference to the drawings. This embodiment includes a cylinder block in which a piston 2 is accommodated in a cylinder of an engine 1 to form a combustion chamber 3, and a liquid cooling type cooling device for cooling members around the cylinder block. A main body of the engine 1 including a cylinder block and members around the cylinder block is a cooling target portion 10 that is cooled by heat exchange with the refrigerant.

Connected to the combustion chamber 3 are an intake passage 4 for sending intake air into the combustion chamber 3 and an exhaust passage 5 for sending exhaust gas from the combustion chamber 3. The intake passage 4 and the exhaust passage 5 are opened and closed to the combustion chamber 3 by an intake valve 6 and an exhaust valve 7. Reference numeral 8 in the figure denotes an ignition device that generates an ignition spark in the combustion chamber 3. The engine 1 of this embodiment is a gasoline engine, but the ignition device 8 is not provided when the engine 1 is a diesel engine.

The liquid cooling type cooling device of the embodiment is a water cooling type cooling device using water (hereinafter referred to as cooling water) as a refrigerant. The water-cooled cooling device includes a pump device 11 called a water pump that sends out cooling water, and a radiator 20 that is a core for cooling the cooling water. The pump device 11, the object to be cooled 10, and the radiator 20 are annularly connected via a refrigerant passage, thereby constituting a refrigerant circulation circuit 21 that circulates cooling water. The pump device 11 has a function of sending out the cooling water by the driving force of the electric motor or the driving force of the engine. The radiator 20 has a function of reducing the temperature of the cooling water by heat exchange with air or the like.

Cooling water is supplied to a space such as a water jacket provided in the cylinder block of the engine 1 by the pump device 11, and the cooling water causes an excessive temperature rise of the engine 1 due to combustion of fuel in the combustion chamber 3. Suppressed. The cooling water is cooled by the radiator 20 and then circulates again to the main body side of the engine 1 via the pump device 11.

Since the refrigerant circulation circuit 21 is provided with a valve 22, the cooling water can be circulated in the refrigerant circulation circuit 21 when the valve 22 is opened, and the cooling water is supplied to the refrigerant circulation circuit 21 when the valve 22 is closed. Will be unable to circulate.

In this water-cooled cooling device, a bypass circulation passage 13 branched from the middle of the refrigerant circulation circuit 21 is provided, and the bypass circulation passage 13 cools the cooling water from the pump device 11 without passing through any heat exchanger. The target unit 10 is constantly circulated. A water temperature sensor 12 serving as a refrigerant temperature acquisition means is provided in the bypass circulation passage 13 to detect information correlated with the cooling water temperature in the cooling target unit 10, and based on the information of the water temperature sensor 12, the temperature of the refrigerant ( Hereinafter, if the temperature of the cooling water, which is the refrigerant of this embodiment, is referred to as the water temperature) is equal to or higher than the first predetermined value T1, the valve 22 is opened, and the cooling water is cooled by the drive of the pump device 11 The cooling water can be circulated through the refrigerant circulation circuit 21 by being fed into the section 10. When it is desired to raise the temperature when the engine 1 is warming up or the like, if the water temperature is lower than the first predetermined value T1, the valve 22 is closed and the cooling water is not sent to the cooling target portion 10 of the engine 1 That is, the control for stopping the supply of the cooling water to the cooling target portion 10 and promoting the warm-up of the engine 1 is performed.

The water-cooled cooling device is controlled by an electronic control unit 60 provided in a vehicle on which the engine 1 is mounted. The electronic control unit 60 controls the operation of the engine 1 and also controls the water-cooled cooling device according to the temperature condition of the cooling target unit 10, the water temperature, various operating conditions, and the like.

In addition, this water-cooled cooling device is supplied with a refrigerant (cooling water) common to the refrigerant circulation circuit 21 to increase the temperature of the refrigerant, or to lower the temperature of the refrigerant and lower in cooling performance of the refrigerant than the radiator 20. Three sub

refrigerant circulation circuits

31, 41, 51 each including three

sub heat exchangers

30, 40, 50 are provided. That is, each of the

sub heat exchangers

30, 40, 50 has a lower heat exchange performance with the refrigerant than the radiator 20. The

sub heat exchangers

30, 40, 50 are designed such that the amount of refrigerant flowing out per unit time is smaller than that of the radiator 20. When cooling water having the same temperature condition flows in, the

sub heat exchanger

30, 40, 50 is sub heat exchanged. The temperature of the cooling water after being radiated through the

vessels

30, 40, 50 becomes higher than the temperature of the cooling water after passing through the radiator 20.

The first sub heat exchanger 30 is composed of a liquid-cooled engine oil cooler that cools the lubricating oil of the engine 1 with cooling water common to the refrigerant circulation circuit 21. Hereinafter, in this embodiment, the sub heat exchanger 30 is referred to as an engine oil cooler 30.

Since the valve 32 is provided in the sub refrigerant circulation circuit 31 including the engine oil cooler 30, if the valve 32 is opened, the cooling water can be circulated through the sub refrigerant circulation circuit 31 including the engine oil cooler 30, If the valve 32 is closed, the cooling water cannot be circulated through the sub refrigerant circulation circuit 31.

The sub refrigerant circulation circuit 31 including the engine oil cooler 30 is joined to the refrigerant circulation circuit 21 on the downstream side of the radiator 20 and the upstream side of the valve 22 to circulate the cooling water to the sub refrigerant circulation circuit 31. It may be configured to be commonly controlled by the valve 22 of the refrigerant circulation circuit 21. In this case, the cooling water is supplied to the radiator 20 and the cooling water is supplied to the engine oil cooler 30 at the same time.

The engine 1 includes an exhaust gas recirculation device 15 that recirculates a part of the exhaust gas discharged from the combustion chamber 3 to the intake air as exhaust gas recirculation gas and introduces it into the combustion chamber 3. The exhaust gas recirculation device 15 includes an exhaust gas recirculation gas passage 16 that connects the air intake passage 4 and the exhaust gas passage 5, an exhaust gas recirculation valve 17 that opens and closes the exhaust gas recirculation gas passage 16, and a merge of the exhaust gas recirculation gas passage 16 and the air intake passage 4. A throttle valve (not shown) that is provided in the intake passage 4 upstream of the air passage to guide the intake passage 4 to a negative pressure state, a liquid-cooled exhaust gas recirculation gas cooler 40 provided in the middle of the exhaust gas recirculation gas passage 16, etc. I have.

The second sub heat exchanger 40 is constituted by an exhaust gas recirculation gas cooler provided in the exhaust gas recirculation device 15. Hereinafter, in this embodiment, the sub heat exchanger 40 is referred to as an exhaust gas recirculation gas cooler 40. The exhaust gas recirculation gas cooler 40 cools the exhaust gas recirculation gas passing through the core connected to the exhaust gas recirculation gas passage 16 by the cooling water circulated through the core. The cooling water supplied to the exhaust gas recirculation gas cooler 40 is common cooling water with the refrigerant circulation circuit 21 including the radiator 20.

Since the sub refrigerant circulation circuit 41 is provided with a valve 42, if the valve 42 is opened, cooling water can be circulated to the sub refrigerant circulation circuit 41 including the exhaust gas recirculation gas cooler 40, and the valve 42 is closed. Then, the cooling water cannot be circulated through the sub refrigerant circulation circuit 41.

The vehicle equipped with this engine 1 is provided with an air conditioner 53. The air conditioner 53 includes a heater core 50 that is provided to generate warm air in the passenger compartment.

The third sub heat exchanger 50 is composed of a heater core provided in the air conditioner 53. Hereinafter, in this embodiment, the sub heat exchanger 50 is referred to as a heater core 50. The heater core 50 is provided with an electric blower fan, and cooling water common to the refrigerant circulation circuit 21 including the radiator 20 is supplied into the core. If the blower fan is rotated, the amount of heat of the cooling water is radiated to the air sent out into the passenger compartment, and hot air is generated, so that the temperature in the passenger compartment can be raised.

The sub refrigerant circulation circuit 51 including the heater core 50 branches on the downstream side of the exhaust gas recirculation gas cooler 40 of the sub refrigerant circulation circuit 41, and then passes through the heater core 50 and on the downstream side of the valve 42 of the sub refrigerant circulation circuit 41. It joins the circuit 41 and returns to the pump device 11. Since the valve 52 is provided on the downstream side of the heater core 50 in the sub refrigerant circulation circuit 51, if the valve 52 is opened, the cooling water can be circulated through the sub refrigerant circulation circuit 51 including the heater core 50. If 52 is closed, the cooling water cannot be circulated in the sub refrigerant circulation circuit 51.

The sub refrigerant circulation circuit 51 including the heater core 50 may be branched on the upstream side of the exhaust gas recirculation gas cooler 40 of the sub refrigerant circulation circuit 41, or the sub refrigerant circulation circuit 51 may be divided into the sub refrigerant circulation circuit 31 and the sub refrigerant circulation circuit 31. Similar to the refrigerant circulation circuit 41, the refrigerant circulation circuit 41 may be directly drawn out from the cooling target unit 10.

These

valves

32, 42, 52 of the air conditioner 53 and the sub

refrigerant circulation circuits

31, 41, 51 are all controlled by the electronic control unit 60.

In this embodiment, as the

valves

22, 32, 42, 52, rotary valves that control the flow rate by rotating members such as a rotor are employed. If a member such as a rotor is rotated, the

valves

22, 32, 42, 52 are opened, and an amount of cooling water corresponding to the rotation speed flows, and if the rotation of the member is stopped, the

valves

22, 32, 42, 52 is closed to stop the flow of cooling water. As the

valves

22, 32, 42, 52, valve devices having other configurations having a function of controlling the flow rate of the fluid may be employed instead of the rotary valves.

The air conditioner 53 having the heater core 50 can be manually controlled based on an input signal when the driver operates the vehicle interior air conditioning switch 61 and the vehicle interior fan switch 62 provided in the vehicle interior, and can also control the temperature in the vehicle interior. It can also be set to be automatically controlled based on information from the vehicle interior temperature detection means 63 for detecting and the outside air temperature detection means 64 for detecting the temperature outside the vehicle.

In manual control, air blowing occurs based on the ON signal of the vehicle interior fan switch 62, and air blowing stops when the OFF signal or the ON signal stops. It is also possible to set the intensity of the air blow at the ON signal. Further, based on the ON signal of the vehicle interior air conditioning switch 61, the air passes through the core, and the air at normal temperature is switched to hot air having a higher temperature to perform heating. When the vehicle interior air conditioning switch 61 is turned off or stopped, the supply of hot air is switched to the normal temperature. In automatic control, the presence / absence of air flow and the temperature and intensity of hot air are automatically controlled so that the temperature in the vehicle interior approaches the set temperature (target temperature), and the set temperature is automatically set based on the temperature outside the vehicle. Can also be set.

In conventional air conditioners, cooling water is generally supplied to the heater core at all times. However, in the present invention, the air conditioner 53 can be set so that the valve 52 of the sub refrigerant circulation circuit 51 is closed and the cooling water is not supplied to the heater core 50 when the vehicle interior is not required to be heated. Therefore, it can suppress that the temperature of cooling water falls unexpectedly according to an operating condition.

Here, the conditions that do not require heating of the vehicle interior include a case where the temperature detected by the intake air temperature sensor 9, the outside air temperature detection means 64, and the vehicle interior temperature detection means 63 is equal to or higher than a predetermined temperature, or the vehicle interior air conditioning switch 61. Or when the vehicle interior fan switch 62 is OFF.

The control of the engine cooling system of the present invention will be described below.

The basic configuration of the control is first when the water temperature is less than a preset first predetermined value T1 under operating conditions that require an early temperature increase, such as during warm-up operation of the engine 1 (region of FIG. 3). a), the cooling water of the refrigerant circuit 21 including the radiator 20 is stopped from being supplied to the cooling target portion 10 of the engine 1. This stop can be performed by closing the valve 22 of the refrigerant circuit 21. At this time, the cooling water of the refrigerant circuit 21 including the radiator 20 may not be completely stopped from being supplied to the cooling target portion 10 of the engine 1 but may be controlled to suppress the supply amount. By stopping or suppressing the supply of cooling water to the object to be cooled 10, the supply of cooling water to the radiator 20 and the sub heat exchanger is also stopped or suppressed.

At this time, the pump device 11 is continuously driven when the engine 1 is in operation, and the

other valves

32, 42, and 52 are also closed. Therefore, the cooling water sent from the pump device 11 is supplied to the radiator 20 or the sub It circulates in the bypass circulation passage 13 that does not pass through any heat exchanger such as the engine oil cooler 30, the exhaust gas recirculation gas cooler 40, and the heater core 50 that are heat exchangers.

In addition, as the valve 22 of the refrigerant circulation circuit 21, a valve that opens only under the condition of the water temperature equal to or higher than the first predetermined value T1 may be adopted by the function of the thermostat.

When the water temperature rises with the warm-up operation of the engine 1 and the water temperature becomes equal to or higher than the first predetermined value T1, the cooling water that has passed through the heat exchanger is supplied to the cooling target portion 10 of the engine 1. Start.

Here, when the supply of the cooling water via the heat exchanger to the cooling target portion 10 of the engine 1 is started or when the supply suppression is canceled, the water temperature is set to a value higher than the first predetermined value T1. If it is less than the second predetermined value T2 (see regions b, c, d in FIG. 3), the valve 22 is closed and the supply of the cooling water to the radiator 20 is stopped, and the valve 32, the valve 42, and the valve 52 are sequentially or selectively opened, and supply of cooling water to the engine oil cooler 30, the exhaust gas recirculation gas cooler 40, and the heater core 50, which are sub heat exchangers, is started sequentially or selectively.

At this time, the exhaust gas recirculation gas cooler 40 that is a sub heat exchanger of the sub refrigerant circulation circuit 41 is defined as a first type sub heat exchanger H that raises the water temperature. Further, the engine oil cooler 30 that is a sub heat exchanger of the sub refrigerant circulation circuit 31 and the heater core 50 that is a sub heat exchanger of the sub refrigerant circulation circuit 51 are defined as a second type sub heat exchanger C that lowers the water temperature. To do.

When the cooling water is supplied to the sub heat exchanger when the water temperature is equal to or higher than the first predetermined value T1 and lower than the second predetermined value T2, the water temperature is set between the first predetermined value T1 and the second predetermined value T2. If it is less than the third predetermined value T3 (see region b in FIG. 3), the cooling water is supplied to the first type sub heat exchanger H, and the second type sub heat exchanger C is supplied. Stop supplying cooling water.

The first type sub heat exchanger H is a radiator, and the cooling water receives the heat of the exhaust gas recirculation gas so that the temperature rises. Therefore, the first type sub heat exchanger C is preceded by the first type sub heat exchanger C. By supplying the cooling water whose temperature has risen somewhat after passing through the exchanger H to the cooling target portion 10 of the engine 1, it is possible to avoid the hindering of the temperature rise due to the low temperature cooling water flowing into the engine 1 at a stretch. be able to.

Then, when the water temperature is equal to or higher than the third predetermined value T3 (see the areas c and d in FIG. 3), the supply of the cooling water to the second-type sub heat exchanger C is started. Since the water temperature has risen to the third predetermined value T3 or higher, even if the cooling water has passed through the sub heat exchanger that lowers the temperature of the cooling water, the water temperature of the refrigerant circuit 21 that has passed through the radiator 20 has increased. As long as it is not extremely low like cooling water, even if it supplies to the engine 1, temperature rise is not inhibited.

Here, the two sub-heat exchanger C, as a sub-heat exchanger to lower the temperature of the cooling water, a relatively cooling performance is low small capacity sub heat exchanger C _S, relatively cooling performance is high and a large sub-heat exchanger C _L.

Here, when supplying the cooling water to the second type sub heat exchanger C, the water temperature is lower than a fourth predetermined value T4 set between the first predetermined value T1 and the second predetermined value T2 ( the reference area c) of FIG. 3, first, performs a supply of cooling water to the small capacity sub heat exchanger C _S, and to stop the supply of cooling water to the high capacity sub-heat exchanger C _L. Thus, before the large sub heat exchanger C _L relatively water temperature is low, the engine 1 relatively high water temperature cooling water which has passed through the cooling performance is low small capacity sub heat exchanger C _S Will be supplied.

By the way, in this embodiment, since 1st type sub heat exchanger H and 2nd type sub heat exchanger C are used together as a sub heat exchanger, 4th predetermined value T4 is set to 1st type sub heat exchanger. It is set between the third predetermined value T3 related to the boundary condition of the operation between the exchanger H and the second type sub heat exchanger C and the second predetermined value T2. If the first type sub heat exchanger H and the second type sub heat exchanger C are not used together and only the second type sub heat exchanger C is adopted as the sub heat exchanger, the fourth predetermined The value T4 is set between the first predetermined value T1 and the second predetermined value T2.

Then, if the water temperature becomes a fourth predetermined value T4 or more (see the region d of FIG. 3) is to supply the refrigerant to the high capacity sub-heat exchanger C _L. Already, water temperature, since a fourth predetermined value T4 or more, even relatively temperature which has passed through the large sub heat exchanger C _L is a low cooling water, the water temperature, passes through the radiator 20 As long as it is not extremely low like the cooling water of the refrigerant circulation circuit 21, even if it supplies to the engine 1, temperature rise is not inhibited.

In this embodiment, as a small-capacity sub heat exchanger C _S of the two sub-heat exchanger C, employing an engine oil cooler 30, as a large-capacity sub heat exchanger C _L, it employs a heater core 50. When supplying cooling water to the engine oil cooler 30, the valve 32 is opened, and when supplying cooling water to the heater core 50, the valve 52 is sequentially opened.

Finally, when the water temperature becomes equal to or higher than the second predetermined value T2 (see region e in FIG. 3), supply of cooling water to the radiator 20 is started. Since the water temperature has risen to the second predetermined value T2 or more and the temperature rise has been completed, there is no problem even if cooling water having a low water temperature that has passed through the radiator 20 is supplied to the engine 1, and thereafter the cooling water is The engine 1 exhibits a predetermined cooling performance.

The graph of FIG. 2 shows the cylinder temperature (liner temperature) when the supply of cooling water to the radiator 20 is stopped and the cooling water is supplied only to the exhaust gas recirculation gas cooler 40 after the warm-up operation of the engine 1 is started. Show. As a behavior of the cylinder temperature, a line indicated by X in the figure is obtained when only the valve 42 is opened and the others are closed. The line indicated by X + Y in the figure is when both the valve 42 and the valve 52 are opened and the others are closed. A line indicated by X + Y + Z in the drawing is the one when the valve 42, the valve 52, and the valve 22 are opened.

In the figure, the line indicated by X + Y + Z indicates that the cooling water that has passed through the radiator 20 is supplied to the engine 1, and therefore the increase in the cylinder temperature is slow. Although the line indicated by X + Y in the figure is supplied with cooling water to both the exhaust gas recirculation gas cooler 40 and the heater core 50, the cooling water is not supplied to the radiator 20, and therefore the cylinder is more than the line indicated by X + Y + Z in the figure. The temperature rises faster. The line indicated by X in the figure shows that the cooling water is supplied only to the exhaust gas recirculation gas cooler 40, and no cooling water is supplied to the heater core 50 and the radiator 20, so that the degree of increase in the cylinder temperature is the fastest. Further, the amount of temporary decrease in the cylinder temperature when the supply of cooling water to the engine 1 is started (the amount of undershoot at the time indicated by symbol a in the figure) is also reduced.

Conventionally, during warm-up operation, the flow of cooling water in the engine is stopped as much as possible, and the temperature distribution in each part of the engine is made uneven, that is, the heat transfer from the high temperature part to the low temperature part is obstructed. For this reason, there is a demand to improve the fuel efficiency during warm-up by raising the temperature of the cylinder liner portion, which is considered to have a large influence on friction, at an early stage.

However, the flow of low-temperature cooling water from the refrigerant circuit including the radiator is automatically controlled by a thermostat, and the radiator-type refrigerant circuit has a large capacity required for engine cooling. Therefore, the flow rate is large and the heat dissipation is large. For this reason, even if the thermostat is opened with a very small opening, a relatively large amount of low-temperature cooling water flows into the engine all at once and the temperature is raised at an early stage, but temporary supercooling occurs. There was a problem. The occurrence of this supercooling is considered to be affected by the amount of inflowing cooling water per unit time, the temperature of the cooling water after being radiated by the heat exchanger, and the like.

Therefore, in the present invention, as described above, after the water temperature of the engine 1 has risen to some extent by the warm-up promotion control that restricts the supply of cooling water from the refrigerant circuit 21 including the radiator 20 (the first predetermined value T1). In fact, when starting the supply of the cooling water that has passed through the heat exchanger, the water flow control valve corresponding to the thermostat in the conventional radiator system is not suddenly opened, but rather than the refrigerant circulation circuit 21 including the radiator 20. Start supplying cooling water to the sub heat exchanger with relatively low cooling performance (relatively small flow rate or low heat dissipation) or the sub heat exchanger that raises the water temperature first. It is what. Thereafter, when the water temperature rises and the temperature rise is completed (corresponding to the second predetermined value T2), the cooling water is supplied to the refrigerant circulation circuit 21 including the radiator 20.

That is, with two large and small heat exchangers with different cooling performances, when warming up, use a heat exchanger with a relatively small cooling performance first, or reduce the temperature of the cooling water and the cooling water. By using a heat exchanger that raises the temperature and using a method that uses the heat exchanger that raises the temperature of the cooling water first when warming up, it is possible to suppress overcooling and undershoot of the engine cylinder temperature Can do.

Here, in the sub refrigerant circulation circuit including the sub heat exchanger that lowers the temperature of the cooling water, the cooling performance needs to be relatively smaller than that of the refrigerant circulation circuit 21 including the radiator 20 that is the main cooling system. is there. Here, in order for the cooling performance to be relatively small, for example, when viewed from the engine 1 side, the inflow cooling water amount per unit time, and from the heat exchanger side, the outflow water amount per unit time, that is, outflow A small amount of refrigerant is required. Further, the temperature of the cooling water after passing through the sub heat exchanger and dissipating heat, that is, the temperature of the refrigerant, should be higher than the temperature of the cooling water after passing through the radiator 20 of the main cooling system, that is, the temperature of the refrigerant. More preferable.

Regarding the conditions of the inflow cooling water amount and the outflow water amount per unit time described above, for example, the water flow resistance of the sub refrigerant circulation circuit including the sub heat exchanger rather than the refrigerant circulation circuit 21 including the radiator 20 which is the main cooling system. It can be realized by increasing. Specifically, a method of narrowing (squeezing) the pipe diameter inside the core of the sub heat exchanger than the pipe system inside the core of the radiator 20 of the main cooling system can be mentioned.

The temperature condition of the cooling water after heat radiation can be realized by reducing the capacity of the sub heat exchanger as compared with the radiator 20 of the main cooling system. Specifically, this can be realized by reducing the heat radiation amount and the heat radiation area by a method such as shortening the pipe length of the sub refrigerant circulation circuit including the sub heat exchanger.

For example, the heater core 50 employed as a sub heat exchanger has a pipe diameter inside the core smaller than that of the radiator 20 and the entire volume of the heater core 50 is smaller than the core of the radiator 20. Resistance is large and heat dissipation tends to be small. Depending on the installation position of the heater core 50, the pipe length of the sub refrigerant circulation circuit 51 including the heater core 50 may be longer than the pipe length of the refrigerant circulation circuit 21 including the radiator 20. Since the long length is also a factor that increases the water flow resistance, the cooling performance of the sub refrigerant circuit 51 including the heater core 50 exceeds the cooling performance of the refrigerant circuit 21 including the radiator 20 because the pipe length is long. Basically not considered.

Regarding the comparison of the cooling performance, in the case where there are a plurality of sub refrigerant circulation circuits including a sub heat exchanger that lowers the temperature of the refrigerant as well as between the radiator 20 and the sub heat exchanger, It can be said that the same tendency exists between the refrigerant circulation circuits.

In the above embodiment, the engine oil cooler 30, the exhaust gas recirculation gas cooler 40, and the heater core 50 are employed as the sub heat exchanger, and in particular, the exhaust gas recirculation gas cooler 40 is raised to the first type sub heat exchanger H (the temperature of the refrigerant is increased). Sub-heat exchanger), engine oil cooler 30 and heater core 50 are second-type sub-heat exchanger C (sub-heat exchanger that lowers the temperature of the refrigerant), but the present invention is not limited to this embodiment. Various heat exchangers can be adopted as the sub heat exchanger to be controlled by the engine cooling system.

For example, as a sub heat exchanger to be controlled, an embodiment in which only one first type sub heat exchanger H is employed and the second type sub heat exchanger C is not employed, the first type sub heat exchanger H is employed. , An embodiment in which the second type sub heat exchanger C is not used, an embodiment in which only the second type sub heat exchanger C is used without using the first type sub heat exchanger H, the first An embodiment in which a plurality of second-type sub heat exchangers C are employed without using the seed sub-heat exchanger H is conceivable.

As another example of the sub heat exchanger, a liquid-cooled intercooler that cools intake air with a refrigerant common to the refrigerant circulation circuit 21 including the radiator 20, or a transmission that transmits engine driving force. Examples thereof include a liquid-cooled transmission oil cooler that cools the lubricating oil with a refrigerant common to the refrigerant circuit 21 including the radiator 20. One or a plurality of sub heat exchangers to be controlled can be selected from these various sub heat exchangers.

In this embodiment, the engine cooling system of the present invention has been described with respect to an example in which a water-cooled cooling device using cooling water as a refrigerant is adopted as the liquid-cooled cooling device. A cooling device using other refrigerants such as an oil cooling type cooling device may be adopted.

DESCRIPTION OF SYMBOLS 1 Engine 2 Piston 3 Combustion chamber 4 Intake passage 5 Exhaust passage 6 Intake valve 7 Exhaust valve 8 Ignition device 9 Intake temperature sensor 10 Cooling target part 11 Pump device (water pump)
12 Water temperature sensor 15 Exhaust gas recirculation device 16 Exhaust gas recirculation gas passage 17 Exhaust gas recirculation valve 20 Radiator 21 Refrigerant circulation circuit 22 Valve 30 Engine oil cooler (sub heat exchanger)
31 Sub refrigerant circulation circuit 32 Valve 40 Exhaust gas recirculation cooler (sub heat exchanger)
41 Sub refrigerant circulation circuit 42 Valve 50 Heater core (sub heat exchanger)
51 Sub refrigerant circulation circuit 52 Valve 53 Air conditioner 60 Electronic control unit 61 Car interior air conditioning switch 62 Car interior fan switch 63 Car interior temperature detecting means 64 Outside air temperature detecting means H First-class sub heat exchanger (raises the temperature of the refrigerant) Sub heat exchanger)
C 2nd type sub heat exchanger (sub heat exchanger that lowers the temperature of the refrigerant)
_CS small capacity sub heat exchanger _CL large capacity sub heat exchanger

Claims

A pump device for delivering refrigerant;
A cooling target portion of the engine cooled by heat exchange with the refrigerant;
A radiator for cooling the refrigerant;
A refrigerant circulation circuit for connecting the pump device, the cooling target part, and the radiator to circulate the refrigerant;
A sub refrigerant circulation circuit including a sub heat exchanger to which the refrigerant is supplied and whose heat exchange performance is lower than that of the radiator;
Refrigerant temperature acquisition means for acquiring information correlated with the temperature of the refrigerant in the cooling target section;
With
When the temperature of the refrigerant is lower than the first predetermined value during the warm-up operation, the supply of the refrigerant to the radiator and the sub heat exchanger is suppressed, the temperature of the refrigerant rises, and the temperature of the refrigerant When it becomes one predetermined value or more, the supply suppression of the refrigerant is released,
When releasing the suppression, if the temperature of the refrigerant is less than a second predetermined value set to a value higher than the first predetermined value, supply of the refrigerant to the radiator is stopped and the sub heat exchange is performed. An engine cooling system that supplies a refrigerant to a heater and supplies the refrigerant to the radiator when the temperature of the refrigerant is equal to or higher than the second predetermined value.
The engine cooling system according to claim 1, wherein the sub heat exchanger has an amount of refrigerant flowing out of the sub heat exchanger per unit time smaller than that of the radiator.
The engine according to claim 1 or 2, wherein the temperature of the refrigerant after the sub heat exchanger passes through the sub heat exchanger and is dissipated is higher than the temperature of the refrigerant after passing through the radiator. Cooling system.
When the temperature of the refrigerant is lower than the first predetermined value during the warm-up operation, the supply of the refrigerant to the radiator and the sub heat exchanger is stopped, the temperature of the refrigerant rises, and the temperature of the refrigerant The engine cooling system according to any one of claims 1 to 3, wherein supply of the refrigerant to the sub heat exchanger is started when the first predetermined value or more is reached.
The sub refrigerant circulation circuit includes, as the sub heat exchanger, a first type sub heat exchanger that increases the temperature of the refrigerant and a second type sub heat exchanger that decreases the temperature of the refrigerant,
When supplying the refrigerant to the sub heat exchanger, if the temperature of the refrigerant is less than a third predetermined value set between the first predetermined value and the second predetermined value, the first type sub When the refrigerant is supplied to the heat exchanger and the supply of the refrigerant to the second type sub heat exchanger is stopped, and the temperature of the refrigerant is equal to or higher than the third predetermined value, the second type sub heat is supplied. The engine cooling system according to claim 4, wherein the refrigerant is supplied to the exchanger.
The sub refrigerant circulation circuit includes a small capacity sub heat exchanger with relatively low cooling performance and a large capacity sub heat exchanger with relatively high cooling performance as the sub heat exchanger for lowering the temperature of the refrigerant,
When supplying the refrigerant to the sub heat exchanger that lowers the temperature of the refrigerant, when the temperature of the refrigerant is less than a fourth predetermined value set between the first predetermined value and the second predetermined value Supplies the refrigerant to the small-capacity sub-heat exchanger and stops supplying the refrigerant to the large-capacity sub-heat exchanger, and if the refrigerant temperature is equal to or higher than the fourth predetermined value, The engine cooling system according to claim 4 or 5, wherein the refrigerant is supplied to the capacity sub heat exchanger.
The engine includes an exhaust gas recirculation device that recirculates a part of the exhaust gas to the intake air as an exhaust gas recirculation gas,
The exhaust gas recirculation device includes a liquid-cooled exhaust gas recirculation cooler that cools the exhaust gas recirculation gas with the refrigerant,
The engine cooling system according to any one of claims 1 to 6, wherein the sub heat exchanger includes the exhaust gas recirculation gas cooler.
The sub heat exchanger is
The engine cooling system according to any one of claims 1 to 7, further comprising a heater core provided in an air conditioner of a vehicle on which the engine is mounted.
The sub heat exchanger is
A liquid-cooled engine oil cooler that cools the engine lubricating oil with the refrigerant;
A liquid-cooled intercooler for cooling the intake air with the refrigerant,
9. The apparatus according to claim 1, further comprising a single element or a plurality of elements selected from a liquid-cooled transmission oil cooler that cools a lubricating oil of a transmission to which engine driving force is transmitted with the refrigerant. The engine cooling system described.