JP2018123724A - Cooling system for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cooling system for more suitably improving performance of an internal combustion engine by using a simple configuration in the cooling system comprising two cooling systems.SOLUTION: A cooling system for an internal combustion engine includes: an intercooler provided downstream of a compressor provided in an intake passage of the internal combustion engine; a first cooling system that is a cooling system connected to the internal combustion engine to cool the internal combustion engine; and a second cooling system that is a cooling system connected to the intercooler to cool intake air passing through the intercooler. The cooling system further includes a heat pipe for transferring heat through change of a phase of working fluid. An evaporation portion side of the heat pipe is provided in a predetermined section in the intake passage downstream of the compressor and upstream of the intercooler, and a condensation portion side of the heat pipe is provided in the first cooling system.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a cooling system for an internal combustion engine.

  A cooling system connected to the internal combustion engine (hereinafter also referred to as “cooling system of the internal combustion engine”) and a cooling system connected to the water cooling intercooler (hereinafter referred to as “cooling system of the water cooling intercooler”) There is also known a cooling system provided with two cooling systems. And in patent document 1, in such a cooling system, the technique provided with the switching means of a flowing water path | route so that a cooling water can be poured from any cooling system to the thermal radiation part which each cooling system has is disclosed. ing.

Japanese Patent No. 3422036

  In a cooling system provided with two cooling systems, an internal combustion engine cooling system and a water cooling intercooler cooling system, if there is a surplus in the cooling capacity of the internal combustion engine cooling system, the surplus cooling capacity is By using it for the cooling system of the cooler, cooling of the intake air can be promoted, thereby improving the performance of the internal combustion engine. And conventionally, the cooling capacity of the surplus was utilized for the cooling system of the water cooling intercooler by switching the flow path of the cooling water. However, when switching the flow path of the cooling water, control associated with the switching is required.

  It is an object of the present invention to provide a cooling system that suitably improves the performance of an internal combustion engine with a simple configuration in a cooling system provided with two cooling systems.

  In order to solve the above problems, an internal combustion engine cooling system according to the present invention is connected to an intercooler provided in the intake passage downstream of a compressor provided in the intake passage of the internal combustion engine, and the internal combustion engine. A system comprising: a first cooling system that is a cooling system that cools the internal combustion engine; and a second cooling system that is connected to the intercooler and cools intake air that passes through the intercooler. A hydraulic fluid enclosed in the casing; an evaporation portion that is a portion where the hydraulic fluid evaporates; and a condensing portion that is a portion where the vapor of the hydraulic fluid condenses. A heat pipe that moves heat by changing, wherein the evaporator side of the heat pipe is downstream of the compressor and upstream of the intercooler. Provided at a predetermined interval in the road, the condensing side of the heat pipe comprises a heat pipe provided in the first cooling system.

Here, the heat pipe moves heat from the evaporation section to the condensation section by the phase change of the working fluid. Specifically, when the atmospheric temperature on the evaporation part side of the heat pipe is higher than the atmospheric temperature on the condensation part side, the working liquid evaporates in the evaporation part, and the vapor of the working liquid condenses in the condensing part. The heat of the atmosphere is moved to the atmosphere on the condensing part side. Therefore, in the above cooling system, when the temperature of a predetermined section in the intake passage provided with the evaporation portion side of the heat pipe is higher than the temperature of the first cooling system provided with the condensation portion side of the heat pipe, the intake passage Thus, the heat of the intake air flowing through the predetermined section moves to the first cooling system. On the other hand, when the temperature of the predetermined section in the intake passage provided with the evaporation portion side of the heat pipe is lower than the temperature of the first cooling system provided with the condensation portion side of the heat pipe, the heat pipe Heat is not transferred from the system to the intake air flowing through a predetermined section in the intake passage.

  ADVANTAGE OF THE INVENTION According to this invention, in the cooling system provided with two cooling systems, the cooling system which improves the performance of an internal combustion engine suitably with a simple structure can be provided.

It is a figure showing a schematic structure of a cooling system of an internal-combustion engine concerning an embodiment of the present invention. It is a figure which shows the concept of a heat pipe. It is a figure for demonstrating the effect | action of the heat pipe in embodiment of this invention, Comprising: It is a figure which shows the heat flow in a high water temperature cooling system and a low water temperature cooling system, and the change of intake air temperature.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be exemplarily described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the component parts described in this embodiment are not intended to limit the scope of the present invention only to those unless otherwise specified.

<System configuration>
FIG. 1 is a diagram showing a schematic configuration of a cooling system for an internal combustion engine according to the present embodiment. FIG. 1 shows an intake / exhaust system of the internal combustion engine together with a cooling system of the internal combustion engine. An internal combustion engine 1 shown in FIG. 1 is a water-cooled internal combustion engine.

  First, the intake / exhaust system of the internal combustion engine 1 will be described. The internal combustion engine 1 is connected to the intake passage 4. In the intake passage 4, an air cleaner 41, a compressor 61 of a supercharger 6 that operates using exhaust energy as a drive source, an evaporator 33 side of a heat pipe 3 to be described later, and a water-cooled intercooler 2 are provided in order according to the flow of intake air. ing. An air flow meter (not shown) is provided in the air cleaner 41 into which outside air is introduced, and the air flow meter outputs an electric signal corresponding to the amount (mass) of intake air (air) flowing through the intake passage 4. Is input to an ECU (not shown). The compressor 61 can supercharge intake air from the air cleaner 41. The heat pipe 3 provided with a later-described evaporation section 33 side in a predetermined section in the intake passage 4 (hereinafter sometimes referred to as “intake passage 4a”) downstream of the compressor 61 and upstream of the water-cooled intercooler 2 is: The heat of the intake air flowing through the predetermined section in the intake passage 4a can be moved to the high water temperature cooling system 7 described later. Details of the heat pipe 3 will be described later. The water cooling intercooler 2 cools the intake air using cooling water of a low water temperature cooling system 8 described later. Then, the intake air that has passed through the water-cooled intercooler 2 is sucked into the internal combustion engine 1. The intake passage 4 between the water-cooled intercooler 2 and the internal combustion engine 1 is provided with a throttle valve (not shown). The throttle valve changes the cross-sectional area of the intake passage 4 so that the internal combustion engine Adjust the intake air amount of 1.

  The internal combustion engine 1 is connected to the exhaust passage 5. A turbine 62 of the supercharger 6 is provided in the middle of the exhaust passage 5. The exhaust passage 5 is opened to the atmosphere via a catalyst and a silencer (not shown).

Next, a cooling system for an internal combustion engine according to the present embodiment will be described. A high water temperature cooling system 7 that cools the internal combustion engine 1 is connected to the internal combustion engine 1. In the present embodiment, the high water temperature cooling system 7 corresponds to the first cooling system in the present invention. The high water temperature cooling system 7 includes a first cooling circuit 71, a first radiator 72, a thermostat 73, and a first water pump 74. The cooling water of the high water temperature cooling system 7 is a low water temperature cooling system whose temperature will be described later. 8 is higher than the cooling water temperature. In the high water temperature cooling system 7, the first water pump 74 pumps the cooling water of the first cooling circuit 71. Specifically, cooling water is pumped from a first cooling circuit 71 (represented as a flow path 71a in FIG. 1) between the thermostat 73 and the first water pump 74. Then, the first water pump 74 discharges the cooling water to the water jacket of the internal combustion engine 1, whereby the cooling water is supplied to the water jacket of the internal combustion engine 1.

  A first cooling circuit 71 is connected to the water jacket outlet of the internal combustion engine 1 (represented as a flow path 71b in FIG. 1), and is supplied by the first water pump 74 and flows through the water jacket. Returns to the first cooling circuit 71. Then, the cooling water in the flow path 71 b flows into the first radiator 72. The first radiator 72 takes heat from the cooling water by exchanging heat between the cooling water and the outside air. Then, the first water pump 74 pumps the cooling water of the first radiator 72 through the first cooling circuit 71 so that the cooling water circulates through the first cooling circuit 71. As a result, the internal combustion engine 1 is cooled by the cooling water cooled by the first radiator 72. The first cooling circuit 71 between the first radiator 72 and the first water pump 74 through which the cooling water cooled by the first radiator 72 circulates is provided with a condenser 34 side of the heat pipe 3 to be described later. ing. Details of the heat pipe 3 will be described later.

  The thermostat 73 is connected to a flow path 71c branched from the flow path 71b, and the thermostat 73 switches between conduction and blocking of the flow path 71c. Specifically, the thermostat 73 makes the flow path 71c conductive when the temperature of the cooling water is lower than a predetermined temperature (for example, 90 ° C.). Further, at this time, the thermostat 73 blocks the first cooling circuit 71 (represented as a flow path 71d in FIG. 1) between the heat pipe 3 and the thermostat 73. Thereby, the internal combustion engine 1 can be warmed up early. On the other hand, when the temperature of the cooling water is equal to or higher than the predetermined temperature, the thermostat 73 blocks the flow path 71c and makes the flow path 71d conductive. However, the above is an example, and the thermostat 73 can simultaneously conduct both the flow path 71c and the flow path 71d. In this case, the flow rate on the flow channel 71c side and the flow rate on the flow channel 71d side are adjusted by the thermostat 73.

  The water cooling intercooler 2 is connected to a low water temperature cooling system 8 that cools intake air that passes through the water cooling intercooler 2. In the present embodiment, the low water temperature cooling system 8 corresponds to the second cooling system in the present invention. The low water temperature cooling system 8 includes a second cooling circuit 81, a second radiator 82, and a second water pump 83. In the low water temperature cooling system 8, cooling water is pumped from the second radiator 82 by the second water pump 83. The second radiator 82 takes heat from the cooling water by exchanging heat between the cooling water and the outside air. Then, the cooling water cooled by the second radiator 82 flows into the water-cooled intercooler 2 via the second cooling circuit 81 (this flow path is represented as a flow path 81a in FIG. 1). And the water cooling intercooler 2 cools intake air using the cooling water. Then, the cooling water of the water-cooled intercooler 2 is returned to the second radiator 82 via the second cooling circuit 81 (this flow path is represented as the flow path 81b in FIG. 1), whereby the second cooling is performed. Cooling water circulates through the circuit 81. For the second water pump 83, for example, an electric pump is used.

Here, when the operating state of the internal combustion engine 1 belongs to the supercharging region, the intake air is supercharged by the compressor 61 and the intake air temperature sucked into the internal combustion engine 1 tends to be high. When the intake air temperature of the internal combustion engine 1 increases, for example, when the internal combustion engine 1 is a gasoline engine, abnormal combustion such as knocking and pre-ignition is likely to occur in the cylinder. Also,
When the intake air temperature of the internal combustion engine 1 is high, the charging efficiency is lower than when the intake air temperature is low, and the output of the internal combustion engine 1 tends to decrease. Therefore, the water-cooled intercooler 2 is used to cool the intake air supercharged by the compressor 61. Here, it becomes easier to cool the intake air as the temperature of the cooling water flowing through the water-cooled intercooler 2 is lower. Therefore, it is desirable that the temperature of the cooling water of the low water temperature cooling system 8 connected to the water cooling intercooler 2 be as low as possible. Further, as the temperature of the intake air flowing into the water-cooled intercooler 2 is lower, the temperature of the intake air flowing out from the water-cooled intercooler 2, that is, the intake air temperature of the internal combustion engine 1 tends to be lower. Therefore, it is desirable that the temperature of the intake air flowing into the water-cooled intercooler 2 is as low as possible.

<Heat pipe>
FIG. 2 is a diagram illustrating the concept of the heat pipe 3. As shown in FIG. 2, the heat pipe 3 has a casing 31 that encloses the hydraulic fluid therein. And the heat pipe 3 moves heat using the phase change of a hydraulic fluid. Here, in FIG. 2, a portion where the working fluid evaporates in the heat pipe 3 is referred to as an evaporation portion 33, and a portion where the working fluid vapor condenses in the heat pipe 3 is referred to as a condensing portion 34. Further, it is assumed that the atmosphere on the evaporation portion 33 side of the heat pipe 3 is higher than the atmosphere on the condensation portion 34 side. In such a heat pipe 3, the working fluid in the evaporation section 33 absorbs the heat of the atmosphere on the high temperature side. Then, the working fluid that has absorbed the heat evaporates, and the working fluid vapor moves to the condensing unit 34. Then, the hydraulic fluid vapor that has moved to the condensing unit 34 is condensed by releasing heat to the low temperature atmosphere. That is, the heat of the high temperature side atmosphere moves to the low temperature side atmosphere. The condensed hydraulic fluid is refluxed to the evaporation unit 33 by the action of gravity, for example.

  And the heat pipe 3 moves heat only from the evaporation part 33 side to the condensation part 34 side. That is, when the temperature on the evaporation part 33 side of the heat pipe 3 is higher than the temperature on the condensation part 34 side, heat is transferred from the evaporation part 33 side to the condensation part 34 side, and the temperature on the evaporation part 33 side of the heat pipe 3 If the temperature is lower than the temperature on the condensing unit 34 side, heat is not transferred.

  In the cooling system for the internal combustion engine according to the present embodiment, as shown in FIG. 1 above, the evaporation portion 33 side of the heat pipe 3 is provided in a predetermined section in the intake passage 4a, and the condensation portion 34 of the heat pipe 3 is provided. The side is provided in the first cooling circuit 71 between the first radiator 72 and the thermostat 73. The operation of the internal combustion engine cooling system according to this embodiment will be described below.

<Action>
FIG. 3 is a view for explaining the operation of the heat pipe 3, and is a diagram showing the heat flow in the high water temperature cooling system 7 and the low water temperature cooling system 8, and the change in the intake air temperature. The operating state of the internal combustion engine 1 in FIG. 3 belongs to the supercharging region, and intake air at a high temperature is supercharged by the compressor 61. And the intake air supercharged by the compressor 61 becomes high temperature. Here, the temperature of the intake air supercharged by the compressor 61 tends to be higher than the temperature of the cooling water in the high water temperature cooling system 7. When the temperature of the intake air supercharged by the compressor 61 becomes higher than the temperature of the cooling water of the high water temperature cooling system 7, the heat of the intake air is absorbed by the evaporation section 33 of the heat pipe 3, and the heat is absorbed by the heat pipe 3. It is discharged to the high water temperature cooling system 7 by the condenser 34. As a result, as shown in FIG. 3, the heat of the intake air flowing through a predetermined section in the intake passage 4a (hereinafter, also referred to as “intake of the predetermined section”) moves to the high water temperature cooling system 7, The intake air is cooled. Here, when the heat of the intake air in a predetermined section is released to the first cooling circuit 71 between the first radiator 72 and the thermostat 73 as shown in FIG. Then, the cooling water that has received the heat flows into the first radiator 72 through the water jacket of the internal combustion engine 1, and is finally radiated by the first radiator 72.

Note that the heat of the intake air in the predetermined section may be directly discharged to the first radiator 72 without passing through the first cooling circuit 71. In this case, for example, the condenser 34 side of the heat pipe 3 is provided in the first radiator 72. As described above, when the heat of the intake air in the predetermined section is directly discharged to the first radiator 72, for example, as much as possible even when the flow rate of the cooling water circulating through the first cooling circuit 71 is small. Can be transferred to the high water temperature cooling system 7.

  The intake air cooled by the heat pipe 3 in this way flows into the water-cooled intercooler 2. Then, the heat of the intake air passing through the water-cooled intercooler 2 moves to the second radiator 82, whereby the intake air is cooled. As a result, the intake air temperature of the internal combustion engine 1 is relatively low.

  Here, the cooling system for the internal combustion engine according to the present embodiment includes the heat pipe 3, and in comparison with a system that does not include the heat pipe 3, the operation state of the internal combustion engine 1 belongs to the supercharging region. The temperature of the intake air flowing into the water-cooled intercooler 2 can be lowered. Thereby, the intake air temperature of the internal combustion engine 1 can be lowered as compared with a system that does not include the heat pipe 3. When the intake air temperature of the internal combustion engine 1 becomes low, for example, when the internal combustion engine 1 is a gasoline engine, abnormal combustion such as knocking and pre-ignition is unlikely to occur in the cylinder, so the ignition timing may be advanced. it can. In other words, the internal combustion engine cooling system according to the present embodiment enables the advance of the ignition timing when the operating state of the gasoline engine to which the cooling system is applied belongs to the supercharging region. Fuel consumption can be reduced. Further, when the intake air temperature of the internal combustion engine 1 is lowered, the charging efficiency of the internal combustion engine 1 is increased and the output of the internal combustion engine 1 is easily increased.

  On the other hand, when the operating state of the internal combustion engine 1 does not belong to the supercharging region, the intake air is not supercharged by the compressor 61, so that the temperature of the intake air after passing through the compressor 61 remains at a high temperature. Easy to be. In this case, the temperature of the intake air in the predetermined section tends to be lower than the temperature of the cooling water in the high water temperature cooling system 7. Here, in the cooling system for the internal combustion engine according to the present embodiment, the system is configured so that the heat pipe 3 transfers heat only from the intake air in the predetermined section to the high water temperature cooling system 7. It becomes difficult for the heat of the cooling water of the cooling system 7 to move to the intake air in the predetermined section.

  If, in a predetermined section of the intake passage 4a, the heat of the intake air flowing through the predetermined section is moved to the high water temperature cooling system 7 by means not based on the configuration of the present invention, the intake air and the high water temperature cooling system in the predetermined section are moved. Heat can move in both directions between the two. In this case, when the temperature of the intake air in the predetermined section is lower than the temperature of the cooling water in the high water temperature cooling system 7, the heat of the cooling water in the high water temperature cooling system 7 easily moves to the intake air in the predetermined section. The heat thus moved is radiated to the low water temperature cooling system 8 when the intake air that has received the heat flows into the water cooling intercooler 2. That is, heat is transferred from the high water temperature cooling system 7 to the intake air in a predetermined section, and as a result, heat is transferred from the high water temperature cooling system 7 to the low water temperature cooling system 8. As a result, the temperature of the cooling water in the low water temperature cooling system 8 rises. When the temperature of the cooling water in the low water temperature cooling system 8 rises, the intake air temperature of the internal combustion engine 1 tends to increase in the next supercharging operation.

  In the present embodiment, since the heat pipe 3 transfers heat only from the intake air in the predetermined section to the high water temperature cooling system 7, when the operating state of the internal combustion engine 1 does not belong to the supercharging region, the high water temperature cooling system 7 It becomes difficult for heat to move to the low water temperature cooling system 8. That is, the cooling system for the internal combustion engine according to the present embodiment can suppress an increase in the temperature of the cooling water in the low water temperature cooling system 8 when the operating state of the internal combustion engine 1 does not belong to the supercharging region. As a result, an increase in the intake air temperature of the internal combustion engine 1 in the next supercharging operation can be suppressed, which contributes to a reduction in fuel consumption in the internal combustion engine 1 and an increase in the output of the internal combustion engine 1.

  As described above, the cooling system for an internal combustion engine according to the present embodiment enables the performance of the internal combustion engine 1 to be preferably improved by the simple configuration of the heat pipe 3.

DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine 2 ... Water cooling intercooler 3 ... Heat pipe 4 ... Intake passage 5 ... Exhaust passage 6 ... Supercharger 7 ... High water temperature cooling system 8 ... Low water temperature cooling system 31 .. Casing 33.. Evaporation section 34. Condensing section 61. Compressor 71.

Claims (1)

An intercooler provided in the intake passage downstream of the compressor provided in the intake passage of the internal combustion engine;
A first cooling system that is connected to the internal combustion engine and cools the internal combustion engine;
A cooling system for an internal combustion engine having a second cooling system that is connected to the intercooler and that cools intake air that passes through the intercooler,
A casing, a hydraulic fluid enclosed in the casing, an evaporation portion that is a portion where the hydraulic fluid evaporates, and a condensing portion that is a portion where the vapor of the hydraulic fluid condenses, the hydraulic fluid Is a heat pipe that moves heat by phase change, wherein the evaporation portion side of the heat pipe is provided in a predetermined section in the intake passage downstream of the compressor and upstream of the intercooler. A cooling system for an internal combustion engine, wherein the condensing part side of the pipe includes a heat pipe provided in the first cooling system.

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