JP5760774B2 - Cooling device for internal combustion engine - Google Patents

Description

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

  2. Description of the Related Art Conventionally, in many internal combustion engines, cooling water that has passed through a cylinder block is supplied to a cylinder head (for example, Patent Document 1), thereby warming up the cylinder head with cooling water that has received engine heat. Is promoted.

JP 2004-301003 A

  By the way, after the engine warm-up is completed, the optimum temperature differs between the cylinder head and the cylinder block. From the viewpoint of suppressing the occurrence of knocking, it is desirable that the temperature of the cylinder head be lower than that of the cylinder block. However, in the conventional cooling device, since the cooling water that has received the engine heat by the cylinder block is supplied to the cylinder head, it is difficult to cool the cylinder head more than the cylinder block.

  Therefore, if a bypass passage capable of supplying cooling water to the cylinder head without passing through the cylinder block is provided, the temperature of the cylinder head can be made lower than that of the cylinder block. However, in this case, since the low-temperature cooling water that has not passed through the cylinder block is supplied to the cylinder head during the warm-up of the engine, the warm-up of the cylinder head is suppressed.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a cooling device for an internal combustion engine capable of suitably cooling and warming up a cylinder head.

In the following, means for achieving the above object and its effects are described.
The invention according to claim 1 is a radiator for cooling cooling water, a water pump for supplying cooling water to the cylinder block, a cylinder head to which cooling water having passed through the cylinder block is supplied, the water pump, It includes a bypass passage that connects the cylinder head directly, and a state for communicating the pre-Symbol bypass passage to the suction port of the water pump, and a switching valve for switching to a state that communicates the bypass passage to the discharge port of the water pump When the engine is warmed up by switching the switching valve, the cooling water discharged from the water pump is supplied to the cylinder head after passing through the cylinder block, and is sucked into the water pump through the bypass passage, Discharged from the water pump at the time of engine cooling request The warming up the却水allowed to flow in the bypass passage in the opposite direction as its gist the supplying cooling water to the cylinder head through the bypass passage.

  According to this configuration, when cooling is requested, the cooling water discharged from the water pump is supplied to the cylinder head through the bypass passage. Accordingly, it becomes possible to supply the cooling water to the cylinder head without passing through the cylinder block, and it is possible to promote the cooling of the cylinder head.

  On the other hand, at the time of warming up, after the cooling water received by the cylinder block is supplied to the cylinder head, the cooling water is sucked into the water pump from the cylinder head through the bypass passage. Therefore, the cooling water that has not passed through the cylinder block is not supplied to the cylinder head, and only the cooling water that has passed through the cylinder block can be supplied to the cylinder head, which promotes warming up of the cylinder head. it can. Thus, according to the configuration, the cylinder head can be cooled and warmed up suitably.

  Further, when the cooling is requested, the bypass passage communicates with the discharge port of the water pump, so that the water jacket provided in the internal combustion engine and the bypass passage both communicate with the discharge port of the water pump. By configuring the parallel circuit in the cooling device in this manner, the pressure loss in the cooling water passage decreases, and the flow rate in the radiator increases. When the flow rate in the radiator is increased, the heat exchange efficiency in the radiator is improved, so that the radiator can be reduced in size.

  Note that the warm-up time in the same configuration refers to a period from when the low-temperature cooling water reaches a predetermined temperature until the warm-up of the engine is completed. Further, the cooling request time refers to a state in which cooling is given priority over engine warm-up, for example, when the engine is at a medium or high load, or when the cooling water temperature exceeds a predetermined determination value.

  According to a second aspect of the present invention, in the cooling device for an internal combustion engine according to the first aspect, the bypass passage is provided with an exhaust cooler that performs heat exchange between the exhaust gas and the cooling water. The gist.

  According to this configuration, when cooling is requested, low-temperature cooling water that has not passed through the cylinder block is supplied to the exhaust cooler, so that the exhaust cooling efficiency is improved. When the cooling efficiency of the exhaust gas is improved in this way, it is possible to reduce the increase in the injection amount for lowering the exhaust temperature performed in the engine high load region, or to narrow the operation region where the increase in the injection amount is required. It is possible to suppress deterioration in fuel consumption associated with execution of injection amount increase.

The gist of the invention described in claim 3 is that, in the cooling device for an internal combustion engine according to claim 1 or 2, a heat exchanger is provided in parallel with the bypass passage.
According to this configuration, when cooling is requested, low-temperature cooling water that has not passed through the cylinder block can be supplied to the heat exchanger, and the cooling effect of the heat exchanger can be enhanced. Further, since the cooling of the heat exchanger with the cooling water is promoted, for example, it is possible to avoid an increase in the size of a member for heat compensation, and it is possible to reduce the size of the heat exchanger. On the other hand, at the time of warming up, since the high-temperature cooling water received by the cylinder block is supplied to the heat exchanger, the temperature rising effect by the heat exchanger can be enhanced.

  As the heat exchanger provided in parallel with the bypass passage, the oil cooler for the internal combustion engine, the oil cooler for the transmission, the EGR cooler, and the turbocharger housing, as described in claim 4. It is possible to adopt a configuration that is at least one of the provided water jackets.

  The gist of the invention according to claim 5 is the cooling apparatus for an internal combustion engine according to any one of claims 1 to 4, wherein a thermostat is connected to the suction port of the water pump. .

  According to this configuration, when the engine is warmed up, the bypass passage communicates with the water pump suction port, so that the bypass passage is arranged in parallel downstream of the water jacket provided in the internal combustion engine. The pressure loss on the downstream side is reduced. When the pressure loss is reduced in this manner, the negative pressure at the suction port of the water pump located on the downstream side of the engine is reduced, so that the negative pressure acting on the thermostat connected to the suction port is also reduced. Therefore, the forced opening of the thermostat due to the negative pressure acting on the thermostat can be suppressed.

  The invention according to claim 6 is the cooling apparatus for an internal combustion engine according to any one of claims 1 to 5, wherein the switching valve is a rotary valve having a cylindrical valve body, and the valve body Is composed of a discharge side valve part to which the discharge side of the water pump is connected and a suction side valve part to which the suction port of the water pump is connected, and the discharge side valve part and the suction side valve part are The gist of the invention is that they are provided in series in the axial direction of the valve body.

  According to this configuration, the passage connected to the discharge side of the water pump and the passage connected to the suction side of the water pump can be switched simultaneously by rotating the valve body of the rotary valve. That is, simultaneous switching of the discharge side passage and the suction side passage can be performed with a simple configuration.

The schematic diagram which shows the whole structure in one Embodiment of the cooling device concerning this invention. Sectional drawing of the rotating shaft direction of the rotary valve which shows the structure of the valve | bulb in the same embodiment typically. Sectional drawing of the radial direction of the rotary valve which shows the state of the valve at the time of warming-up. The schematic diagram which shows the flow of the cooling water at the time of warming up. Sectional drawing of the radial direction of the rotary valve which shows the state of the valve | bulb at the time of cooling request | requirement. The schematic diagram which shows the flow of the cooling water at the time of a cooling request | requirement.

Hereinafter, an embodiment of a cooling device for an internal combustion engine according to the present invention will be described with reference to FIGS.
As shown in FIG. 1, the engine 1 includes a cylinder block 1a and a cylinder head 1b. Each of the cylinder block 1a and the cylinder head 1b is provided with a water jacket through which cooling water flows, and the cooling water that has passed through the cylinder block 1a is supplied to the cylinder head 1b through these water jackets.

  A discharge port of a water pump (WP) 10 is connected to a water jacket inlet of the cylinder block 1a through a supply passage 100. The water pump 10 includes a pump that pumps cooling water and a rotary valve 20 that switches a supply destination of the cooling water.

  A radiator passage 210, a heater passage 220, an oil cooler passage 230, a bypass passage 240, and a turbo passage 250 are connected to the water jacket outlet of the cylinder head 1b.

  The radiator passage 210 is provided with a radiator 40 for cooling the cooling water, and the radiator passage 210 on the downstream side of the radiator 40 is connected to the first inlet port of the thermostat 30. The first inlet port is a port into which cooling water flows when the temperature of the cooling water rises and the thermostat 30 is opened.

  The heater passage 220 is provided with a heater 50 for heating the passenger compartment, and the heater passage 220 on the downstream side of the heater 50 is connected to the second inlet port of the thermostat 30. The second inlet port is a port through which cooling water always flows regardless of the opened state of the thermostat 30.

  The oil cooler passage 230 is provided with an oil cooler 60 for heating and cooling the lubricating oil of the engine 1. The oil cooler passage 230 on the downstream side of the oil cooler 60 is connected to the water pump 10. The rotary valve 20 is connected.

  The bypass passage 240 is a passage that directly connects the water pump 10 and the cylinder head 1b (more specifically, a water jacket of the cylinder head 1b), and is an exhaust cooler 70 that exchanges heat between exhaust gas and cooling water. Is provided. The exhaust cooler 70 itself is integrally formed in the vicinity of the outlet of the exhaust port provided in the cylinder head 1b. A bypass passage 240 on the downstream side of the exhaust cooler 70 is connected to the rotary valve 20.

  The turbo passage 250 is provided with a water jacket 80 formed in a turbocharger (supercharger) housing. The water jacket 80 heats and cools the turbocharger by exchanging heat between the turbocharger housing and the cooling water. The turbo passage 250 on the downstream side of the water jacket 80 is connected to the rotary valve 20.

The suction port of the water pump 10 is connected to the outlet port of the thermostat 30 through the suction passage 600.
Next, the structure of the rotary valve 20 provided in the water pump 10 will be described. The rotary valve 20 is a switching valve that switches the flow direction of the cooling water in the oil cooler passage 230, the bypass passage 240, and the turbo passage 250, and its drive is controlled by the control device 200.

As shown in FIG. 2, the rotary valve 20 includes a valve body 22 provided in the housing 21 of the water pump 10 and various passages formed in the housing 21.
The valve body 22 has a hollow cylindrical shape and is rotationally driven by an appropriate actuator.

  A partition portion 22b is provided inside the valve body 22, and the valve body 22 is divided into two valve portions in the upper and lower directions in the rotation axis direction by the partition portion 22b. More specifically, a portion of the valve body 22 above the partition portion 22b is a discharge side valve portion 22au to which the discharge side of the water pump 10 is connected. Further, a portion of the valve body 22 below the partition portion 22b is a suction side valve portion 22ad to which the suction side of the water pump 10 is connected. The discharge side valve portion 22au and the suction side valve portion 22ad are provided in series in the rotation axis direction of the valve body 22. The partition portion 22b can be formed by using an appropriate seal member or integrally formed with the valve body 22.

  As shown in FIGS. 2 and 3, the discharge-side valve portion 22au is provided with a first opening 22c1, a second opening 22c2, and a third opening 22c3, respectively. The second opening 22c2 is formed at a position shifted by 90 degrees counterclockwise in the circumferential direction of the valve body 22 from the first opening 22c1. Further, the third opening 22c3 is formed at a position shifted from the second opening 22c2 by 90 degrees in the counterclockwise direction of the valve body 22 in the circumferential direction.

  The suction side valve portion 22ad is provided with a fourth opening portion 22c4 and a fifth opening portion 22c5, respectively. The fifth opening 22c5 is formed at a position shifted from the fourth opening 22c4 by 180 degrees in the circumferential direction of the valve body 22. The fourth opening 22c4 is formed below the second opening 22c2.

  As shown in FIGS. 2 and 3, the housing 21 has a first passage 21a communicating with the discharge port of the water pump 10 and a water jacket of the cylinder block 1a around the discharge valve portion 22au. A third passage 21c communicating with the second passage 21b, the oil cooler passage 230, the bypass passage 240, and the turbo passage 250 is formed.

  As shown in FIG. 3, the second passage 21 b is formed at a position shifted from the first passage 21 a by 90 degrees in the clockwise direction of the valve body 22 in the circumferential direction. The third passage 21c is formed at a position shifted from the second passage 21b by 90 degrees in the clockwise direction of the valve body 22 in the circumferential direction. When the engine is warmed up, the rotational phase of the valve body 22 is adjusted so that the first passage 21a communicates with the second opening 22c2, whereby the second passage 21b communicates with the first opening 22c1, The third passage 21c is closed.

  On the other hand, in the housing 21, around the suction side valve portion 22ad, a fourth passage 21d communicating with the suction port of the water pump 10, a fifth passage communicating with the oil cooler passage 230, the bypass passage 240, and the turbo passage 250 is provided. A passage 21e is formed.

  As shown in FIG. 3, the fifth passage 21 e is formed at a position shifted by 180 degrees in the circumferential direction of the valve body 22 from the fourth passage 21 d. When the engine is warmed up, as described above, the rotational phase of the valve body 22 is adjusted so that the first passage 21a communicates with the second opening 22c2, so that the fourth passage 21d becomes the fourth opening 22c4. The formation positions of the fourth passage 21d and the fifth passage 21e are determined so that the fifth passage 21e communicates with the fifth opening 22c5.

  In the cooling device configured as described above, when the engine is warmed up, that is, while the cooling water in the low temperature state does not reach the predetermined temperature and the engine is not warmed up, the control device 200 performs the rotary valve operation. The rotational phase of the 20 valve bodies 22 is controlled, and the rotational phase of the valve body 22 is brought into the state shown in FIG. In this state, as described above, in the discharge side valve portion 22au, the first passage 21a communicates with the second opening 22c2, the second passage 21b communicates with the first opening 22c1, and the third passage 21c is closed. Is done. Therefore, as shown in FIGS. 3 and 4, the cooling water discharged from the water pump 10 is supplied only to the cylinder block 1a.

  On the other hand, in the suction side valve portion 22ad, the fourth passage 21d communicates with the fourth opening 22c4 and the fifth passage 21e communicates with the fifth opening 22c5. Therefore, as shown in FIGS. 3 and 4, the cooling water received by the cylinder block 1a and discharged from the cylinder head 1b is supplied to the oil cooler 60, the exhaust cooler 70, and the water jacket 80 of the turbocharger. It is sucked into the water pump 10.

  On the other hand, when the engine is requested to be cooled, that is, in a request state in which the cooling is given priority over the engine warm-up, the rotation phase of the valve element 22 of the rotary valve 20 is controlled by the control device 200, Is brought into the state shown in FIG. 5 (the state rotated 90 degrees clockwise from the warm-up state). It should be noted that the determination as to whether or not the engine cooling request is made by the control device 200 is performed based on the determination as to whether the current engine load is a medium or high load or the cooling water temperature exceeds a predetermined determination value. This is done by determining whether or not.

  In the state shown in FIG. 5, in the discharge side valve portion 22au, the first passage 21a communicates with the third opening 22c3, the second passage 21b communicates with the second opening 22c2, and the third passage 21c is the first. It communicates with the opening 22c1. Therefore, as shown in FIGS. 5 and 6, the cooling water discharged from the water pump 10 is not only for the cylinder block 1a but also for the oil cooler 60, the exhaust cooler 70, and the water jacket 80 of the turbocharger. It is supplied directly without passing through.

  On the other hand, in the suction side valve portion 22ad, the fourth passage 21d and the fifth passage 21e are closed by the wall surface of the suction side valve portion 22ad. Therefore, as shown in FIG. 6, the coolant supplied directly to the oil cooler 60, the exhaust cooler 70, and the water jacket 80 of the turbocharger without passing through the engine 1 has passed through the engine 1. The coolant merges with the cylinder head 1b. The merged cooling water is then sucked into the water pump 10 via the radiator 40 and the heater 50.

Next, the operation of this embodiment will be described.
(Operation during warm-up)
The bypass passage 240 that directly connects the water pump 10 and the cylinder head is communicated with the suction port of the water pump 10 when the engine is warmed up. Therefore, the cooling water received by the cylinder block 1a is supplied to the cylinder head 1b and then sucked into the water pump 10 from the cylinder head 1b through the bypass passage 240. Accordingly, the cooling water that has not passed through the cylinder block 1a is not supplied to the cylinder head 1b, and only the cooling water that has passed through the cylinder block 1a can be supplied to the cylinder head 1b. The opportunity is promoted.

  Further, an oil cooler passage 230 and a turbo passage 250 are provided in parallel with the bypass passage 240, the oil cooler 60 serving as a heat exchanger is provided in the oil cooler passage 230, and a water jacket 80 serving as a heat exchanger is provided in the turbo passage 250. Is provided. As shown in FIG. 4 above, since the high-temperature cooling water received by the cylinder block 1a and the cylinder head 1b is supplied to these heat exchangers during warm-up, the temperature rise effect by the heat exchanger is increased. Get higher. Therefore, for example, the viscosity of the lubricating oil for the engine 1 or turbocharger can be promoted in the warming-up process, thereby improving the fuel consumption.

A thermostat 30 is connected to the suction port of the water pump 10. Here, at the time of warming up, the bypass passage 240 is communicated with the suction port of the water pump 10, whereby the bypass passage 240 is arranged in parallel downstream of the water jacket provided in the engine 1. The pressure loss on the downstream side is reduced. When the pressure loss is reduced in this way, the negative pressure at the suction port of the water pump 10 located on the downstream side of the engine is reduced, so that the negative pressure acting on the thermostat 30 connected to the suction port is also reduced. Therefore, the forced valve opening of the thermostat 30 due to the negative pressure acting on the thermostat 30 is suppressed. By suppressing the forced opening of the thermostat 30 during warm-up in this way, it is possible to prevent the coolant from passing through the radiator 40 during warm-up, thereby reducing the warm-up performance of the engine. Can be suppressed.
(Action when cooling is required)
After the engine warm-up is completed, the optimum temperature differs between the cylinder head 1b and the cylinder block 1a. From the viewpoint of suppressing the occurrence of knocking, the temperature of the cylinder head 1b may be lower than that of the cylinder block 1a. desirable.

  Therefore, the bypass passage 240 that directly connects the water pump 10 and the cylinder head is communicated with the discharge port of the water pump 10 when the engine is requested to be cooled. Therefore, the cooling water discharged from the water pump 10 is supplied to the cylinder head 1b through the bypass passage 240. Thus, since it becomes possible to supply cooling water to the cylinder head 1b without passing through the cylinder block 1a, cooling of the cylinder head 1b can be promoted, and the temperature of the cylinder head 1b is made lower than that of the cylinder block 1a. can do.

  Further, when the cooling is requested, the bypass passage 240 is communicated with the discharge port of the water pump 10 so that the water jacket provided in the engine 1 and the bypass passage 240 are both communicated with the discharge port of the water pump 10. become. By configuring the parallel circuit in the cooling device in this manner, the pressure loss in the cooling water passage is reduced, and the flow rate in the radiator 40 is increased. When the flow rate in the radiator 40 is increased, the heat exchange efficiency in the radiator 40 is improved, so that the radiator 40 can be reduced in size.

  Further, the bypass passage 240 is provided with an exhaust cooler 70 for exchanging heat between the exhaust and the cooling water, and when cooling is requested, the low-temperature cooling water that has not passed through the cylinder block 1a is exhaust-cooled. It supplies to the container 70. Therefore, the cooling efficiency of the exhaust gas is improved. When the cooling efficiency of the exhaust gas is improved in this way, it is possible to reduce the increase in the injection amount for lowering the exhaust temperature performed in the engine high load region, or to narrow the operation region where the increase in the injection amount is required. It is possible to suppress deterioration in fuel consumption associated with execution of injection amount increase.

Further, an oil cooler passage 230 and a turbo passage 250 are provided in parallel with the bypass passage 240, the oil cooler 60 serving as a heat exchanger is provided in the oil cooler passage 230, and a water jacket 80 serving as a heat exchanger is provided in the turbo passage 250. Is provided. And as shown in previous FIG. 6, since the low temperature cooling water which has not passed the cylinder block 1a is supplied to these heat exchangers at the time of a cooling request | requirement, the cooling effect by a heat exchanger becomes high. Further, since the cooling of the heat exchanger with the cooling water is promoted, for example, it is possible to avoid an increase in the size of a member for heat compensation, and it is possible to reduce the size of the heat exchanger.
(Other effects)
In the rotary valve 20 having the cylindrical valve body 22, the valve body 22 includes a discharge side valve portion 22au to which the discharge side of the water pump 10 is connected, and a suction side valve portion 22ad to which the suction port of the water pump 10 is connected. The discharge side valve portion 22au and the suction side valve portion 22ad are provided in series in the axial direction of the valve body 22. Therefore, the passage connected to the discharge side of the water pump 10 and the passage connected to the suction side of the water pump 10 can be simultaneously switched by rotating the valve body 22. That is, simultaneous switching of the discharge side passage and the suction side passage can be performed with a simple configuration.

As described above, according to the present embodiment, the following effects can be obtained.
(1) A bypass passage 240 for directly connecting the water pump 10 and the cylinder head 1b is provided. A rotary valve 20 is provided as a switching valve that connects the bypass passage 240 to the suction port of the water pump 10 when the engine is warmed up, and connects the bypass passage 240 to the discharge port of the water pump 10 when the engine is required to be cooled. I have to. Therefore, the cylinder head 1b can be suitably cooled and warmed up.

Further, since the flow rate in the radiator increases when cooling is requested, the radiator can be reduced in size.
(2) The bypass cooler 240 is provided with an exhaust cooler 70 that exchanges heat between the exhaust and the cooling water. Therefore, the cooling efficiency of exhaust gas is improved when cooling is requested. Further, by improving the exhaust cooling efficiency in this way, it is possible to suppress the deterioration of fuel consumption due to the execution of the injection amount increase in the high load region of the engine.

  (3) An oil cooler 60 that is a heat exchanger and a water jacket 80 of a turbocharger are provided in parallel with the bypass passage 240. Therefore, the cooling effect by these heat exchangers can be enhanced when cooling is required. Moreover, since the cooling of the heat exchanger with the cooling water is promoted, the heat exchanger can be downsized. On the other hand, at the time of warming up, the temperature rising effect by the heat exchanger can be enhanced.

  (4) In the cooling device in which the thermostat 30 is connected to the suction port of the water pump 10, the above-described bypass passage 240 and the rotary valve 20 are provided. Therefore, the forced valve opening of the thermostat 30 due to the negative pressure acting on the thermostat 30 is suppressed during warm-up.

  (5) In the rotary valve 20 having the cylindrical valve body 22, the discharge side valve portion 22 au and the suction side valve portion 22 ad are provided in series in the axial direction of the valve body 22. Therefore, simultaneous switching of the discharge side passage and the suction side passage can be performed with a simple configuration.

In addition, the said embodiment can also be changed and implemented as follows.
-As the heat exchanger provided in parallel with the bypass passage 240, the oil cooler 60 for the internal combustion engine and the water jacket 80 provided in the housing of the supercharger are applied. You may make it apply. For example, an oil cooler or an EGR cooler for a transmission may be applied. That is, at least one of an oil cooler for an internal combustion engine, an oil cooler for a transmission, an EGR cooler, and a water jacket provided in the housing of the supercharger may be provided. By increasing such parallel circuits, the pressure loss on the downstream side of the engine at the time of warm-up is promoted, so that the forced opening of the thermostat 30 described above can be further suppressed. In addition, since the pressure loss in the cooling water passage at the time of the cooling request is promoted, the flow rate in the radiator 40 is further increased. For example, the radiator 40 can be further downsized.

  Although a heat exchanger is provided in parallel with the bypass passage 240, such a heat exchanger may be omitted. Even in this case, the effects described in (1), (2), (4), and (5) can be obtained.

The exhaust cooler 70 provided in the bypass passage 240 may be omitted. Even in this case, the effects described in (1), (3), (4), and (5) can be obtained.
Although the exhaust cooler 70 is formed integrally with the cylinder head 1b, it may be provided separately. Further, such an exhaust cooler may be provided at any part of the exhaust system.

  Although the rotary valve 20 is built in the water pump 10, the rotary valve 20 and the water pump 10 may be separated and connected to each other through an appropriate passage.

-The structure of the rotary valve 20 mentioned above is an example, and you may apply another structure.
The drive of the rotary valve 20 is controlled by the control device 200. In addition, the rotational phase of the rotary valve 20 may be changed using a material that deforms according to temperature, such as bimetal.

  DESCRIPTION OF SYMBOLS 1 ... Engine, 1a ... Cylinder block, 1b ... Cylinder head, 10 ... Water pump, 20 ... Rotary valve, 21 ... Housing, 21a ... First passage, 21b ... Second passage, 21c ... Third passage, 21d ... Fourth Passage, 21e ... fifth passage, 22 ... valve body, 22b ... partition, 22ad ... suction side valve, 22au ... discharge side valve, 22c1 ... first opening, 22c2 ... second opening, 22c3 ... third Opening, 22c4 ... 4th opening, 22c5 ... 5th opening, 30 ... Thermostat, 40 ... Radiator, 50 ... Heater, 60 ... Oil cooler, 70 ... Exhaust cooler, 80 ... Water jacket, 100 ... Supply passage, 200 ... Control device, 210 ... Radiator passage, 220 ... Heater passage, 230 ... Oil cooler passage, 240 ... Bypass passage, 250 ... Turbo passage, 6 0 ... suction passage.

Claims (6)

A radiator for cooling the cooling water;
A water pump for supplying cooling water to the cylinder block;
A cylinder head supplied with cooling water that has passed through the cylinder block;
A bypass passage directly connecting the water pump and the cylinder head;
And a state communicating the pre Symbol bypass passage to the suction port of the water pump, and a switching valve for switching to a state that communicates the bypass passage to the discharge port of the water pump,
By switching the switching valve, when the engine is warmed up, the cooling water discharged from the water pump is supplied to the cylinder head after passing through the cylinder block and is sucked into the water pump through the bypass passage. The cooling water discharged from the water pump is circulated through the bypass passage in the opposite direction to that during warm-up, and the cooling water is supplied to the cylinder head through the bypass passage. apparatus. The cooling device for an internal combustion engine according to claim 1, wherein an exhaust cooler that performs heat exchange between exhaust gas and cooling water is provided in the bypass passage. The cooling device for an internal combustion engine according to claim 1, wherein a heat exchanger is provided in parallel with the bypass passage. The internal combustion engine according to claim 3, wherein the heat exchanger is at least one of an oil cooler for an internal combustion engine, an oil cooler for a transmission, an EGR cooler, and a water jacket provided in a housing of the supercharger. Cooling system. The cooling device for an internal combustion engine according to any one of claims 1 to 4, wherein a thermostat is connected to the suction port of the water pump. The switching valve is a rotary valve having a cylindrical valve body,
The valve body is composed of a discharge side valve portion to which a discharge side of the water pump is connected and a suction side valve portion to which a suction port of the water pump is connected,
The cooling device for an internal combustion engine according to any one of claims 1 to 5, wherein the discharge side valve portion and the suction side valve portion are provided in series in an axial direction of the valve body.

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