JPH08158871A - Cooling device of internal combustion engine - Google Patents

Abstract

PURPOSE: To prevent an excessive temperature rise of cooling water at the time of a high load during warming up without increasing discharge of a water pump and to cool an intercooler after warming up in an internal combustion engine with a supercharger and the intercooler. CONSTITUTION: A cooling device 20 to circulate cooling water by way of changing cooling water channels 21-23 passing a cooling means 13 and a cooling water channel 24 by-passing it over to each other by a thermostat 40 and an intercooler 5 are furnished. Additionally, a water channel 25 communicated to a flow passage change-over valve 50 through the intercooler 5 from the discharge side of a water pump 30 of cooling water and two water channels 26, 27 respectively communicated to one end and the other end of the cooling means 13 from two discharge ports of the flow passage change-over valve 50 are provided, cooling water of the intercooler 5 is returned without passing the cooling means 13 at the time of a low load during warming up an engine, cooling water of the intercooler 5 is returned through the cooling means 13 at the time of a high load during warming up, and cooling water of the engine 1 and cooling water of the intercooler 5 are both returned through the cooling means 13 after warming up the engine 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling device for an internal combustion engine, and more particularly to a cooling device for an internal combustion engine which can cool an intercooler provided in an intake passage of the internal combustion engine without adding a water pump.

[0002]

2. Description of the Related Art Generally, in a water-cooled internal combustion engine, a cooling device that circulates cooling water in the engine body to cool the engine in order to prevent an excessive temperature rise due to heat generated by combustion in a cylinder. Is provided. Cooling water is pressure-fed by a water pump, cooling the internal combustion engine to raise the temperature of the cooling water is sent to a radiator for cooling, and cooling water of the lower temperature circulates to the internal combustion engine.

In addition, when the internal combustion engine is cold started, the engine body is cold, and it is necessary to warm up the engine to a predetermined temperature. If the cooling water is circulated through the radiator in such a case, the warm-up time of the engine becomes long. Therefore, the cooling device is provided with a bypass passage that bypasses the thermostat and the radiator, and when the cooling water temperature is lower than a predetermined temperature, the cooling water circulates from the bypass passage to the engine through the thermostat and does not pass through the radiator. It is like this.

By the way, in recent years, there are some internal combustion engines equipped with a supercharger and an air cooler (intercooler) in order to improve the output of the internal combustion engine. This intercooler cools the intake air that has been compressed by the supercharger and has risen in temperature to improve the volumetric efficiency of the intake air, and there are air cooling type and water cooling type.
A conventional cooling device for an internal combustion engine equipped with a water-cooled intercooler is disclosed in Japanese Utility Model Laid-Open No. 57-42114. In this cooling device, a flow path switching device provided in the cooling water passage of the engine circulates cooling water between the water pump and the engine during low load during warm-up of the engine, and cools during high load during warm-up. Part of the water is intercooler, water pump,
Supplying to the internal combustion engine to cool the intake air when the engine is under heavy load, and after warming up new cooling water with an intercooler, water pump,
A supply for an internal combustion engine is disclosed.

[0005]

[Problems to be Solved by the Invention]
In the technology disclosed in Japanese Patent Laid-Open No. 57-42114, after the engine is warmed up, the entire amount of cooling water is supplied to the internal combustion engine after passing through the intercooler, that is, since the intercooler and the internal combustion engine are in series, There is a problem that it is necessary to improve the discharge capacity.

Therefore, according to the present invention, the warming-up can be promoted by the cooling water when the engine is warming up and the load is low, and the engine can be warmed up by cooling a part of the cooling water when the engine is warming up. It is possible to prevent the temperature of the cooling water from being increased more than necessary and to cool the cooling water after the warming up without improving the discharge capacity of the water pump. An object is to provide a cooling device.

[0007]

A cooling device for an internal combustion engine according to the present invention, which achieves the above object, comprises a first communication passage communicating between a discharge port of a water pump and a cooling water passage inlet of the internal combustion engine.
A second communication passage that connects the cooling water passage outlet of the internal combustion engine to one end of the cooling water cooling means, a third communication passage that connects the other end of the cooling means and the suction port of the pump, and a second communication passage The first branch point located on the way and the second point located on the way to the third communication passage
And a fourth communication passage communicating with a branch point of the cooling water, and a fourth communication passage provided at the second branch point to communicate the fourth communication passage with a pump when the cooling water temperature is lower than a predetermined temperature. An internal combustion engine equipped with a cooling device, which sometimes comprises a thermostat for communicating the other end of the cooling means with a pump, wherein the intake passage is equipped with an intercooler, and the cooling device is further provided in the middle of the first communication passage. A fifth communicating passage that connects the located third branch point to the cooling water inlet of the intercooler, and a fourth communicating passage that is located closer to the cooling means than the cooling water outlet of the intercooler and the first branch point of the second communicating passage. A sixth communication passage communicating with the branch point, a fifth branch point located in the middle of the sixth communication passage, and a sixth branch point located on the cooling means side of the thermostat of the third communication passage. Provided at the 7th communication passage and the 5th branch point Flow path switching valve, operating state parameter detecting means for detecting operating state parameters of the internal combustion engine, cooling water outlet of the intercooler during warming up of the internal combustion engine and low load, and after warming up of the internal combustion engine Is connected to the second communication passage, and when the internal combustion engine is warming up and the load is high, the flow passage switching valve is connected so that the cooling water outlet of the intercooler communicates with the third communication passage. And a flow path switching valve control means for switching between the two.

[0008]

According to the cooling system for an internal combustion engine of the present invention, the cooling water simultaneously flows through the following two routes according to the warm-up state of the engine and the load state of the engine. (1) When the engine is warming up and under low load Water pump → first communication passage → cooling passage of internal combustion engine → part of second communication passage → fourth communication passage → thermostat → part of third communication passage → water Pump Water pump → Part of 1st communication path → 5th communication path →
Intercooler → 6th communication passage → Part of 2nd communication passage → 4th communication passage → Thermostat → Part of 3rd communication passage → Water pump (2) At high load while engine is warming up Water pump → 1st connection Passage → Cooling passage of internal combustion engine → Part of second communication passage → Fourth communication passage → Thermostat → Part of third communication passage → Water pump Water pump → Part of first communication passage → Fifth communication passage →
Intercooler-> Part of 6th communication path-> 7th communication path-> Part of 3rd communication path-> Cooling means-> Part of 2nd communication path-> 4th communication path->Thermostat-> Part of 3rd communication path-> Water Pump (3) After warming up the engine Water pump → First communication passage → Internal combustion engine cooling passage → Second communication passage → Cooling means → Third communication passage → Water pump Water pump → Part of first communication passage → First passage 5 passages →
Intercooler → Sixth communication path → Part of second communication path → Cooling means → Third communication path → Water pump

[0009]

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 shows a structure of a cooling device 20 of the present invention in an internal combustion engine 1 provided with a supercharger 4 and an intercooler 5. In the intake passage 2 of the internal combustion engine 1, the compressor 4 of the supercharger 4 is arranged from the upstream side to the downstream side of the air cleaner 3.
A, an intercooler 5, and a throttle valve 6 are provided. The compressor 4A of the supercharger 4 is provided coaxially with the turbine 4B provided in the exhaust passage 8 of the internal combustion engine 1. When the turbine 4B is rotated by the exhaust gas, the compressor 4A rotates to compress intake air. There is. The intercooler 5 is a water-cooled type, and lowers the temperature of the intake air that has been compressed by the compressor 4A and increased in temperature to increase the volumetric efficiency of the intake air.

Further, the throttle valve 6 of the intake passage 2 is provided with a load sensor 7 for detecting the load of the engine based on its opening degree, and its output is inputted to an engine control unit (ECU) 10. . Further, a water temperature sensor 9 is provided in the cooling water passage in the main body of the internal combustion engine 1, and the output thereof is also input to the ECU 10.

The internal combustion engine 1 is provided with a cooling device 20 for cooling the internal combustion engine 1 regardless of the presence or absence of the supercharger 4 and the intercooler 5. This cooling device 20 keeps the cooling water that has passed through the internal combustion engine 1 during operation and circulates by cooling the cooling water whose temperature has risen and the cooling water that has passed through the internal combustion engine 1 during cold start without cooling. A path during warming up to improve the warming up characteristics by returning to the internal combustion engine 1. The running route and the warming-up route are performed by a thermostat 40 that switches the passage according to the cooling water temperature.

The route during operation is such that the first communication passage 21 that connects the discharge port of the water pump 30 and the cooling water passage inlet 11 of the internal combustion engine 1, the cooling water passage outlet 12 of the internal combustion engine 1, and the cooling water are cooled. A second communication passage 22 that communicates with one end of the radiator 13 that is a means, and a third communication passage 23 that communicates the other end of the radiator 13 with the suction port of the water pump 30.

The warming-up path is a fourth connecting point that connects a first branch point 31 located in the middle of the second communicating path 22 and a second branch point 32 located in the middle of the third communicating path 23. Passage 24
When the cooling water temperature is lower than a predetermined temperature, the fourth communication passage 24 is provided at the second branch point 32, and the fourth communication passage 24 is connected to the water pump 30.
And a thermostat 40 for connecting the other end of the radiator 13 to the water pump 30 when the cooling water temperature is equal to or higher than a predetermined temperature.

Next, when the internal combustion engine 1 is provided with the supercharger 4 and the intake passage 2 is provided with the intercooler 5, in the embodiment shown in FIG. 1, the cooling path of the intercooler is provided in the cooling device 20 described above. I am adding. The cooling path of the intercooler 5 is the third branch point 3 located in the middle of the first communication passage 21.
No. 3 for communicating the cooling water inlet 5A of the intercooler 5 with each other
The communication passage 25, the cooling water outlet 5B of the intercooler 5, and the second
The sixth communication passage 26 that communicates with the fourth branch point 34 located on the radiator 13 side of the first branch point 31 of the communication passage 22.
And a fifth branch point 35 located in the middle of the sixth communication passage 26.
From the seventh communication passage 27 that communicates with the sixth branch point 36 located on the radiator 13 side of the thermostat 40 of the third communication passage 23, and the flow path switching valve 50 provided at the fifth branch point 35. Composed.

The flow path switching valve 50 is constructed as an electromagnetic three-way valve in this embodiment, and its actuator 51 is driven by a signal from the above-mentioned ECU 10 to connect the paths shown by black-black in the figure. Alternatively, a switching operation is performed to determine whether the path shown in white-white is connected. When the black-black path is connected, the sixth path is provided via the flow path switching valve 50.
The communication passage 26 communicates with the cooling water outlet 5B of the intercooler 5.
The cooling water from the second communication passage 2 passes through the sixth communication passage 26.
Inflow to 2. On the other hand, when the white-white path is connected, the cooling water from the cooling water outlet 5B of the intercooler 5 passes through a part of the sixth communication path 26 and enters the seventh communication path 27,
It flows into the third communication passage 23.

The ECU 10 outputs a flow passage switching signal to the actuator 51 of the flow passage switching valve 50 according to the operating state of the internal combustion engine 1. That is, the ECU 10 determines that the cooling water outlet 5B of the intercooler 5 is in the second communication passage 2 when the internal combustion engine 1 is warming up and at a low load, and after the internal combustion engine 1 is warming up.
2, the flow passage switching valve 50 is switched to connect the black-black path, and when the internal combustion engine 1 is warming up and the load is high, the cooling water outlet 5B of the intercooler 5 is in the third position.
The flow path switching valve 50 is switched so as to communicate with the communication passage 23 so that the white-white path is communicated.

Next, the difference between the warm-up state of the engine and the circulation path of the cooling water according to the load of the engine of the cooling device 20 of the embodiment configured as described above will be described with reference to FIGS. 2 to 4. To do. (1) When the engine is warming up and the load is low [Fig. 2] When the engine is warming up and the load is low, the cooling water temperature is low and the suction port of the water pump 30 is connected to the fourth communication passage 24 via the thermostat 40. Has been done. In this state, EC
U10 connects black-black of the flow path switching valve 50, and connects the cooling water outlet 5B of the intercooler 5 to the sixth communication passage 26.

In this state, the cooling water flows through two paths as shown by the arrows in FIG. After being discharged from the water pump 30, the cooling water flowing through the first passage enters the internal combustion engine 1 from the cooling passage inlet 11 through the first communication passage 21, cools the inside, and then exits from the cooling water outlet 12. It passes through a part of the 2nd communicating path 22, enters into the 4th communicating path 24, and returns from the thermostat 40 to a water pump 30 through a part of the 3rd communicating path 23. After being discharged from the water pump 30, the cooling water flowing through the second path enters the fifth communication path 25 through a part of the first communication path 21 and exchanges heat with the intercooler 5, and then the flow path switching valve 50. Through the second communication passage 22 to the fourth communication passage 24, and from the thermostat 40 to the water pump 30 through a part of the third communication passage 23.

Thus, when the engine is warming up and the load is low,
Since a part of the cooling water flows through the intercooler 5, the intake air (supercharged air) compressed by the supercharger is cooled. Further, since the cooling water is warmed by the supercharged air temperature in the intercooler 5, the warm-up of the internal combustion engine 1 can be promoted. At this time, the supercooled air cooling heat is added to the engine cooling water to accelerate warm-up, and due to the rise in the temperature of the engine intake port wall, port wetting is reduced and emission is reduced. (2) When the engine is warming up and under high load [Fig. 3] When the engine is warming up and under high load, the cooling water temperature is low and the suction port of the water pump 30 is connected to the fourth communication passage 24 via the thermostat 40. This occurs when the engine load suddenly rises due to a sudden depression of the accelerator while connected. At this time, the supercharged air with high pressure and temperature is intercooler 5
It is when it is necessary to increase the cooling capacity of the intercooler 5. In this state, the ECU 10 detects the high load state of the engine by the output from the load sensor 7, connects the white of the flow path switching valve 50 to the white, and connects the cooling water outlet 5B of the intercooler 5 to the seventh communication passage 27. To do.

In this state, the cooling water flows through two paths as shown by the arrows in FIG. After being discharged from the water pump 30, the cooling water flowing through the first passage enters the internal combustion engine 1 from the cooling passage inlet 11 through the first communication passage 21, cools the inside, and then exits from the cooling water outlet 12. It passes through a part of the 2nd communicating path 22, enters into the 4th communicating path 24, and returns from the thermostat 40 to a water pump 30 through a part of the 3rd communicating path 23. After being discharged from the water pump 30, the cooling water flowing through the second path enters the fifth communication path 25 through a part of the first communication path 21 and exchanges heat with the intercooler 5, and then the flow path switching valve 50. Through the seventh communication passage 27, through a part of the third communication passage 23, from the outlet 13B of the radiator 13 into the radiator 13,
After flowing back through the inside of the inlet 13A and passing through a part of the second communication passage 22 into the fourth communication passage 24, the thermostat 4
From 0 to a part of the third communication passage 23, the water pump 3
Return to 0.

In this way, when the engine is warming up and under high load,
Since the cooling water flowing through the intercooler 5 whose temperature has risen due to a large amount of supercharged air is cooled by backflowing the radiator 13, the cooling capacity of the intercooler 5 can be increased. (3) After warming up the engine [Fig. 4] Since the temperature of the cooling water is high after warming up the engine, the thermostat 40
Is opened, and the suction port of the water pump 30 is connected to the third communication passage 23.
It is connected to the radiator 13 via. Further, in this state, the ECU 10 causes the black-black of the flow path switching valve 50 to communicate with each other, and the cooling water outlet 5B of the intercooler 5 is connected to the sixth communication passage 2.
Connected to 6.

In this state, the cooling water flows through two paths as shown by the arrows in FIG. After being discharged from the water pump 30, the cooling water flowing through the first passage enters the internal combustion engine 1 from the cooling passage inlet 11 through the first communication passage 21, cools the inside, and then exits from the cooling water outlet 12. After entering the radiator 13 through the second communication passage 22 from the inlet 13A of the radiator 13, being cooled by the radiator 13, flowing through the radiator 13 and exiting from the outlet 13B, the thermostat 40 is passed through the third communication passage 23. Return to the water pump 30 from. After being discharged from the water pump 30, the cooling water flowing through the second path enters the fifth communication path 25 through a part of the first communication path 21 and exchanges heat with the intercooler 5, and then the flow path switching valve 50. Through the sixth communication passage 26, and through a part of the second communication passage 22 to the inlet 13 of the radiator 13.
It enters into the radiator 13 from A and returns to the water pump 30 similarly to the first path.

As described above, after the engine is warmed up, a part of the cooling water flows through the intercooler 5, so that the intake air (supercharged air) compressed by the supercharger is cooled. In this embodiment, the flow passage switching valve 50 is configured to completely switch the flow passage, but a flow passage switching valve 50 that can adjust the flow rate is used, and when the engine load is small, the flow passage is changed. If the amount of cooling water passing through the switching valve 50 is reduced and the amount of cooling water passing through the flow passage switching valve 50 is increased when the load on the engine is large, the accelerator is suddenly depressed after the engine warms up and the intercooler 5 Even if the temperature of the engine suddenly rises, it is possible to increase the amount of heat exchange by the cooling water and prevent high temperature damage to the engine.

FIG. 5 shows another embodiment of the flow path switching valve 50, and shows the structure of the flow path switching valve 50 capable of adjusting the flow rate of the cooling water. Flow path switching valve 50 of this embodiment
As shown in FIG. 5A, is composed of an actuator (step motor in this embodiment) 51 and a switching valve body 53. The switching valve body 53 is attached to the rotary shaft 52 of the actuator 51, and a switching water passage 54 is provided in the switching valve body 53. As shown in FIG. 5B, the flow passage switching valve 50 includes a sixth communication passage 26 connected to the intercooler 5, a sixth communication passage 26 connected to the second communication passage 22, and a seventh communication passage 27 ( (Not shown) is housed in a housing 55 to which it is connected. The actuator 51 either fully rotates the sixth communication passage 26 by rotating the switching valve body 53 by 90 °, or connects the sixth communication passage 26 connected to the intercooler 5 to the seventh communication passage 27. Can be in the state of.

FIG. 5 (c) is a flow path switching valve 5 shown in FIG. 5 (a).
FIG. 5 is a diagram illustrating the position of the switching valve body 53 (state of the switching water passage 54) when 0 connects the fifth communication passage 25 and the seventh communication passage 27, and FIG. 5 (d) is FIG. 5 (a). 6 is a diagram illustrating the position of the switching valve body 53 (state of the switching water passage 54) when the flow path switching valve 50 of FIG. The flow path switching valve 50 of this embodiment can adjust the flow rate of the cooling water as described above. That is, as shown by the broken line in FIG. 5 (d), the rotation angle of the switching valve body 53 is changed to adjust the degree of overlap between the switching water passage 54 and the sixth communication passage 26, so that when the engine load is small, the flow is reduced. It is possible to reduce the amount of cooling water passing through the passage switching valve 50 and increase the amount of cooling water passing through the passage switching valve 50 when the load on the engine is large. As a result, if the temperature of the cooling water at the inlet 5A of the intercooler 5 is constant, the cooling capacity of the intercooler 5 is improved by increasing the cooling water amount by the flow path switching valve 50, and the temperature of the intercooler 5 is lowered to the maximum water amount. be able to.

The amount of the cooling water for cooling the internal combustion engine 1 is reduced by the amount of the cooling water diverted to the intercooler 5, and the temperature of the cooling water discharged from the cooling water outlet 12 of the internal combustion engine 1 is increased. Since the temperature of the cooling water that has passed through the intercooler 5 also rises due to heat exchange with the intercooler 5,
If the capacity of the radiator 13 is not changed, the radiator 13
The temperature of the cooling water discharged from the plant also rises. When the cooling water temperature rises, the opening degree of the thermostat 40 increases, the inlet resistance of the water pump 30 decreases, and the amount of cooling water increases. As the amount of cooling water increases, the amount of cooling water processed from the radiator 13 increases by the capacity of the radiator 13, and the thermostat 40 controls the flow rate of cooling water according to the required cooling amount of the intercooler and the required cooling amount of the engine. This makes it possible to improve the cooling capacity of the intercooler 5 by the flow path switching valve 50.

FIG. 6 shows an example of the structure of the thermostat 40 provided at the second branch point 32 of FIG.
The thermostat 40 is closed in the casing 44 by the spring 43 when the cooling water temperature is low.
The valve body 42 is provided, and the first valve body 41 that moves in a direction away from the casing 44 when the cooling water temperature is high is provided outside the casing 44. Further, a thermo wax 45 that expands when the cooling water temperature rises is built in the casing 44.
When 5 expands, the first valve body 42 moves in a direction away from the casing 44, and at the same time, the second valve body 42 opens.

The thermostat 40 constructed as described above
Is attached to the housing 40 with the dome portion 46 having an opening (not shown) exposed to the outside,
A valve seat 15 is provided in a direction in which the first valve body 41 of the housing 14 moves. The first communication passage 21 connected to the water pump 30 is connected to the side surface of the housing 14, and the third communication passage 23 connected to the radiator 13 is connected to the outside of the dome portion 46, and the first communication passage 21 is connected to the valve seat 15. The fourth communication passage 24 is connected to the outside. FIG. 6 shows the state of the thermostat 40 when the cooling water temperature is low,
In this state, since the second valve body 42 seals the dome portion 46, the first communication passage 21 is connected to the fourth communication passage 24. Then, when the cooling water temperature rises from this state, the thermowax 45 expands and the first valve body 41 is raised against the spring 43 to seal the valve seat 15. First
When the valve body 41 of the second valve body rises, the second valve body 42
Also rises to open the dome portion 46. As a result, when the cooling water temperature is high, the first communication passage 21 is connected to the third communication passage 23.

FIG. 7 is a characteristic diagram showing an increase characteristic of the cooling water temperature after starting the engine of the internal combustion engine 1 using the cooling device 20 for the internal combustion engine of the present invention. Cooling device 2 of the embodiment described above
If 0 is used, the temperature of the cooling water increases linearly with the passage of time during warm-up when the engine is cold started at time t1, and after the time t2 when warm-up ends, the thermostat 40
Keeps the water temperature constant.

In such a state, when the accelerator is suddenly depressed while the engine is warming up, the temperature of the cooling water after heat exchange with the intercooler 5 is normally indicated by a broken line due to the rise in the temperature of the supercharged air. However, in the cooling device 20 of the present invention which operates as described above, the cooling water temperature whose temperature has risen is cooled by the radiator 13, so the cooling water temperature rises as shown by the solid line. Even if the accelerator is suddenly depressed after warming up the engine, the temperature of the cooling water after heat exchange with the intercooler 5 normally rises as shown by the broken line even though the temperature of the supercharged air rises. In the cooling device 20 of the invention, by increasing the amount of cooling water flowing through the flow path switching valve 50, the cooling water temperature whose temperature has risen is efficiently cooled by the radiator 13, so the cooling water temperature should be kept constant as indicated by the solid line. It is possible to prevent excessive temperature rise of the internal combustion engine.

[0031]

As described above, according to the cooling device for an internal combustion engine of the present invention, the cooling water is not cooled by the cooling means at the time of low load during warm-up of the engine, and is kept warm during the warm-up of the engine. At high load, part of it is cooled by the cooling means,
After the engine is warmed up, the entire amount is cooled by the cooling means,
When the engine is warming up and the load is low, warming up can be promoted by the cooling water, and when the engine is warming up and under high load, part of the cooling water can be cooled to promote warming up and the cooling water can be promoted. There is an effect that it is possible to prevent an excessive temperature rise, and further, after the warm-up, the cooling water can be efficiently cooled without improving the discharge capacity of the water pump. Therefore, in the present invention, the cooling water can be cooled by the single cooling means and the pump in the internal combustion engine equipped with the supercharger and the water-cooled intercooler, so that the cost can be reduced. Also, an intercooler can be installed without sticking to the cooling water path.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing a configuration of an internal combustion engine provided with a cooling device of the present invention.

FIG. 2 is an explanatory diagram showing a circulation path at a low load during engine warm-up in the internal combustion engine cooling device of FIG. 1;

FIG. 3 is an explanatory diagram showing a circulation path during high load during engine warm-up in the internal combustion engine cooling device of FIG. 1;

FIG. 4 is an explanatory diagram showing a circulation path after completion of engine warming in the internal combustion engine cooling device of FIG. 1;

5 (a) is a perspective view showing the basic structure of an embodiment of the flow path switching valve of FIG. 1, (b) is a sectional view of a housing incorporating the flow path switching valve of (a), (c). Is a diagram for explaining the position of the valve element when the flow passage switching valve of (a) connects the fifth communication passage and the seventh communication passage, and (d) is the flow passage switching valve of (a) fifth communication passage. It is a figure explaining the position of a valve body when connecting a passage and the 6th free passage.

FIG. 6 is a cross-sectional view showing an example of the configuration of a thermostat provided at the second branch point of FIG.

FIG. 7 is a characteristic diagram showing a rising characteristic of a cooling water temperature after engine start of an internal combustion engine using the internal combustion engine cooling device of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine 2 ... Intake passage 4 ... Supercharger 5 ... Intercooler 6 ... Throttle valve 7 ... Load sensor 8 ... Exhaust passage 9 ... Water temperature sensor 10 ... ECU (engine control unit) 13 ... Radiator 14 ... Thermostat housing 15 ... Valve seat 20 ... Cooling device 21-27 ... 1st-7th communication passage 31-36 ... 1st-6th branch point 40 ... Thermostat 41 ... 1st valve body 42 ... 2nd valve body 45 ... Thermo wax 50 ... Flow path switching valve 51 ... Actuator 53 ... Switching valve body 54 ... Switching water channel

Claims (1)

[Claims] 1. A first communication passage that connects a discharge port of a water pump and a cooling water passage inlet of an internal combustion engine, and a second communication passage that communicates a cooling water passage outlet of the internal combustion engine with one end of cooling water cooling means. A passage, a third communicating passage that connects the other end of the cooling means and the suction port of the pump, a first branch point located in the middle of the second communicating passage, and a middle of the third communicating passage A fourth communication passage communicating with the second branch point, and a fourth communication passage provided at the second branch point and communicating the fourth communication passage with the pump when the cooling water temperature is lower than a predetermined temperature. An internal combustion engine having a cooling device including a thermostat that communicates the other end of the cooling means to the pump when the temperature is equal to or higher than a predetermined temperature, and the cooling device further includes an intercooler in the intake passage. Located in the middle of the first communication passage A fifth communication passage that connects the third branch point and the cooling water inlet of the intercooler, a cooling water outlet of the intercooler, and a fifth communication passage that is located closer to the cooling means than the first branch point of the second communication passage. A sixth communication passage communicating with the fourth branch point, a fifth branch point located in the middle of the sixth communication passage, and a sixth communication passage located closer to the cooling means than the thermostat of the third communication passage. A seventh communication passage communicating with the branch point of the internal combustion engine, a flow path switching valve provided at the fifth branch point, an operating state parameter detecting means for detecting an operating state parameter of the internal combustion engine, and an internal combustion engine warming up. In the middle and low load, and after warming up the internal combustion engine, the flow path switching valve is switched so that the cooling water outlet of the intercooler communicates with the second communication passage, and the internal combustion engine is warming up and When the load is high, the intercooler Cooling system for an internal combustion engine 却水 outlet is characterized by providing a flow path switching valve control means for switching the flow path switching valve so as to communicate with the third communication passage.