JP6463139B2 - Engine cooling control device - Google Patents

Description

  The present invention relates to an engine cooling control device. In particular, the present invention relates to an engine cooling control device for suppressing engine knocking.

  In an engine (internal combustion engine) mounted on a vehicle or the like, the engine is cooled by circulating cooling water through a cooling water passage formed in a casing of the engine. The cooling water is cooled by a cooling device typified by a radiator, and is circulated through a cooling water circulation passage including a cooling water passage formed by being pumped and formed in an engine casing.

  Here, the engine is likely to be knocked due to abnormal combustion when the combustion temperature of the fuel in the combustion chamber is high, such as during high-load operation. As one method of suppressing the occurrence of such knocking, a method of cooling the cylinder head of the engine to lower the temperature of the cylinder head is known. Conventionally, in order to achieve both knocking suppression and fuel efficiency improvement, the temperature of cooling water flowing to the cylinder head is lowered to suppress knocking, and the temperature of cooling water flowing to the cylinder block is increased to improve fuel efficiency. System cooling structures have been proposed.

  For example, in Patent Document 1, a head side cooling water passage formed in a cylinder head, a block side cooling water passage formed in a cylinder block, a head radiator, a block radiator, a head water pump, and a block water. An engine cooling structure including a pump is disclosed. In such an engine cooling structure, during the non-warm-up operation of the engine, control for suppressing knocking is performed by flowing cooling water independently through the head side cooling water passage and the block side cooling water passage.

JP 2013-160183 A

  However, in the engine cooling structure described in Patent Document 1, cooling water circulates through the head side cooling water passage and the block side cooling water passage at all times during non-warm-up operation. Therefore, if the engine is operating for a long time in the knocking region, the temperature of the cooling water circulating in the head-side cooling water passage rises and the cooling effect decreases. In such a case, the engine cooling structure described in Patent Document 1 must further cool the cooling water by the radiator while circulating the cooling water to the cylinder head, thereby reducing the temperature of the cylinder head and suppressing knocking. It may take some time before

  The present invention has been made in view of the above problems, and an object of the present invention is to efficiently reduce the temperature of the cylinder head with low-temperature cooling water when the engine operating state is in the knocking region. An object of the present invention is to provide an engine cooling control device that can reduce knocking and suppress knocking.

In order to solve the above problems, according to an aspect of the present invention, a first cooling water circulation path that passes through a cylinder head and a cylinder block of an engine, and a first cooling water circulating through the first cooling water circulation path. , A first cooling device that cools the cooling water circulating through the first cooling water circulation path, a second cooling water circulation path that passes through the cylinder head of the engine, and the second cooling water circulation path A second pump for circulating cooling water, a second cooling device for cooling the cooling water circulating in the second cooling water circulation path, and a downstream side of the second pump in the second cooling water circulation path And a bypass passage that branches from the upstream side of the cylinder head and joins the upstream side of the second cooling device, and a branch position of the bypass passage, and the discharge port of the second pump is connected to the shim. And a flow path switching valve communicating with the cylinder head side or the bypass passage side, the control device for controlling the second pump and the flow path switching valve, wherein the control unit includes driving state knocking region of the engine When the temperature of the cooling water in the second cooling water circulation path is lower than a predetermined threshold value, the discharge port of the second pump is moved to the cylinder head side by the flow path switching valve. communicating, while circulating the cooling water through the cylinder head, when the temperature of the cooling water in the second cooling water circulation path is equal to or greater than the predetermined threshold value, said by the flow path switching valve the discharge port of the second pump communicating with the bypass passage side, the Ru said not through the cylinder head through the bypass passage to circulate the cooling water lowers the temperature of the cooling water, the engine cooling Your device is provided.

When the temperature of the cooling water in the second cooling water circulation path is lower than a predetermined threshold value and the operating state of the engine is not in the knocking region, the control device uses the flow path switching valve to The discharge port of the second pump may be communicated with the bypass passage side.

  According to the engine cooling control apparatus of the present invention, the temperature of the cooling water circulating through the second cooling water circulation path can be kept low without passing through the cylinder head. Therefore, when the engine operating state is in the knocking region, the cooling water kept at a low temperature can be circulated through the second cooling water circulation path. Thereby, when the engine operating state is in the knocking region, knocking can be suppressed by efficiently lowering the temperature of the cylinder head with low-temperature cooling water.

FIG. 1 is a schematic diagram showing a schematic configuration of an engine cooling system according to an embodiment of the present invention. FIG. 2 is a block diagram illustrating functions of the control device according to the embodiment. FIG. 3 is a flowchart showing an engine cooling control method according to the embodiment. FIG. 4 is a table showing the control contents of the second pump and the flow path switching valve.

  Exemplary embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In addition, in this specification and drawing, about the component which has the substantially same function structure, duplication description is abbreviate | omitted by attaching | subjecting the same code | symbol.

<< 1. Example of overall configuration of engine cooling control device >>
First, an example of the overall configuration of an engine cooling control apparatus 100 according to an embodiment of the present invention will be described. FIG. 1 is a schematic diagram schematically showing an overall configuration example of an engine cooling control apparatus 100. The engine cooling control device 100 is an example applied to a horizontally opposed four-cylinder gasoline engine. However, the engine may be a V-type or row-type conventional engine, and the number of cylinders is not limited to four.

  The engine includes left and right cylinder heads 12L and 12R and left and right cylinder blocks 14L and 14R. The cylinder blocks 14L and 14R have cylinders that move forward and backward as the piston slides. The cylinder heads 12L and 12R are provided at positions where one of the openings at both ends of the cylinder is closed. A combustion chamber is defined by the cylinders of the cylinder blocks 14L and 14R, the piston, and the cylinder heads 12L and 12R. The cylinder heads 12L and 12R are provided with spark plugs so as to face the combustion chamber.

  The cylinder heads 12L and 12R and the cylinder blocks 14L and 14R are respectively formed with water jackets (cooling water flow paths) (not shown). The engine cooling control apparatus 100 includes a first coolant circulation path 20 that circulates coolant while distributing the coolant to the water jackets of the cylinder heads 12L and 12R and the water jackets of the cylinder blocks 14L and 14R. In addition, the engine cooling control apparatus 100 according to the present embodiment, together with the first cooling water circulation path 20, performs the second cooling for circulating the cooling water while supplying the cooling water to the water jackets of the cylinder heads 12 </ b> L and 12 </ b> R. A water circulation path 40 is provided.

(First cooling water circulation path)
The first cooling water circulation path 20 includes a first pump 22 that pumps cooling water and a radiator 30 that cools the cooling water. The first pump 22 may be an electric water pump driven by a motor or the like. A gear pump connected to the crankshaft of the engine via a gear may be used. The radiator 30 is a cooling device that radiates the cooling water to lower the temperature of the cooling water, and corresponds to a first cooling device. The first cooling water circulation path 20 can have the same configuration as the cooling water circulation path provided in the conventional engine.

  While the first pump 22 is driven, the cooling water pumped by the first pump 22 is supplied to the left and right water separation chambers 24L and 24R. The cooling water supplied to the water separation chamber 24L is distributed to the water jackets of the cylinder head 12L and the cylinder block 14L via the cooling water passages 16L and 18L. The cooling water supplied to the water separation chamber 24R is distributed to the water jackets of the cylinder head 12R and the cylinder block 14R via the cooling water passages 16R and 18R. When the cooling water passes through the cylinder heads 12L, 12R and the cylinder blocks 14L, 14R, the heat of the cylinder heads 12L, 12R and the cylinder blocks 14L, 14R moves to the cooling water, and the cylinder heads 12L, 12R and the cylinder blocks 14L, 14R is cooled.

  The ratio of the cooling water distributed from the water separation chamber 24L to the cylinder head 12L and the cylinder block 14L and the ratio of the cooling water distributed from the water separation chamber 24R to the cylinder head 12R and the cylinder block 14R are, for example, 9: 1 can be used. Thereby, cooling of the cylinder heads 12L and 12R having a large influence on the combustion temperature is efficiently performed. The ratio of the cooling water can be adjusted, for example, by changing the ratio of the flow path areas of the cooling water passages 16L and 18L (16R and 18R).

  The cooling water that has passed through the water jacket of the cylinder head 12L and the cylinder block 14R joins in the water collecting chamber 26L, and then flows into the collecting pipe 28. The cooling water that has passed through the water jacket of the cylinder head 12R and the cylinder block 14R joins in the water collecting chamber 26R and then flows into the collecting pipe 28. The cooling water flowing into the collecting pipe 28 is returned to the radiator 30 via the cooling water passage 20a. The cooling water returned to the radiator 30 is radiated and cooled, and then circulates again to the first pump 22 via the thermostat valve 32. Further, a part of the cooling water circulates from the collecting pipe 28 to the first pump 22 via the cooling water passage 20 b and not via the radiator 30 but via the thermostat valve 32.

  In the present embodiment, the cooling water flowing through the collecting pipe 28 flows around an EGR (Exhaust Gas Recirculation) valve 62 and cools the EGR valve 62. In this embodiment, part of the cooling water in the collecting pipe 28 flows to the heater core 74 via the heater cock 72. The heater core 74 is for heating the passenger compartment by exchanging heat with the cooling water. For example, when there is a heating request while the engine is warming up, the heater cock 72 is opened and the cooling water is supplied. It flows to the heater core 74. The cooling water flowing through the heater core 74 is cooled by heat exchange and circulates to the first pump 22 via the thermostat valve 32.

  In the present embodiment, part of the cooling water in the collecting pipe 28 passes through the cooling passage of the throttle chamber 64 provided with a throttle valve. The cooling water that has flowed through the throttle chamber 64 is also circulated to the first pump 22 via the thermostat valve 32.

  The thermostat valve 32 is provided to open and close the suction port of the first pump 22. The thermostat valve 32 closes when the temperature of the cooling water is lower than a predetermined threshold value, and stops the circulation of the cooling water via the radiator 30. On the other hand, the thermostat valve 32 opens when the temperature of the cooling water is equal to or higher than a predetermined threshold, and circulates the cooling water through the radiator 30. Regardless of whether the thermostat valve 32 is open or closed, the flow path of the cooling water circulating from the heater core 74 side and the throttle chamber 64 side to the first pump 22 is opened. The threshold value can be set to 85 ° C., for example.

  The thermostat valve 32 is a thermostat valve 32 with a bottom bypass valve 76, and opens the cooling water passage 20b side when the temperature of the cooling water is lower than a predetermined threshold. Therefore, when the temperature of the cooling water is less than the predetermined threshold, the cooling water that has passed through the cylinder heads 12L and 12R and the cylinder blocks 14L and 14R circulates in the first cooling water circulation path 20 without passing through the radiator 30. Thereby, when the temperature of a cooling water is low, a cooling water can be heated up rapidly. The threshold value can be set to 75 ° C., for example.

  Moreover, in this embodiment, the cooling water pumped by the 1st pump 22 is comprised so that it may flow to the transmission heat exchanger 68 side provided with the transmission. In the transmission heat exchanger 68, the transmission is cooled by transferring the heat of the transmission to the cooling water. The cooling water flowing to the transmission heat exchanger 68 side joins the collecting pipe 28 via the thermostat valve 66. The thermostat valve 66 is opened when the temperature of the cooling water exceeds a predetermined temperature.

(Second cooling water circulation path)
The second cooling water circulation path 40 includes a second pump 42 that pumps the cooling water, a flow path switching valve 44, a radiator 46 that cools the cooling water, and a water tank 48. Similar to the first pump 22, the second pump 42 may be an electric water pump driven by a motor or the like. A gear pump connected to the crankshaft of the engine via a gear may be used. The radiator 46 is a cooling device that radiates the cooling water to lower the temperature of the cooling water, and corresponds to a second cooling device. The water tank 48 stores the cooling water radiated through the radiator 46.

  The flow path switching valve 44 communicates the discharge port of the second pump 42 to the cooling water passages 56L, 56R or the bypass passage 54 on the cylinder heads 12L, 12R side. That is, the flow path switching valve 44 switches whether the cooling water pumped by the second pump 42 passes through the water jacket of the cylinder heads 12L, 12R or bypasses the cylinder heads 12L, 12R. The cooling water flowing toward the cylinder heads 12L, 12R cools the engine heads 12L, 12R by heat exchange, and then returns to the radiator 46 via the water collecting chambers 26L, 26R, the collecting pipe 28, and the cooling water passage 58. . The water jacket formed in the cylinder heads 12L and 12R may be shared with the water jacket of the cylinder heads 12L and 12R in the first coolant circulation path 20, or may be another water jacket.

  In a state where the flow path switching valve 44 is switched to the cooling water passages 56L and 56R, the cooling that circulates in the second cooling water circulation path 40 together with the cooling water that circulates in the first cooling water circulation path 20 The cylinder heads 12L and 12R are cooled by water. That is, the flow rate of the cooling water passing through the water jackets of the cylinder heads 12L and 12R is increased, and the cooling efficiency is improved. Moreover, since the cooling water circulating through the second cooling water circulation path 40 is in a low temperature state, the cooling efficiency of the cylinder heads 12L and 12R is improved. Therefore, the combustion temperature in the combustion chamber is lowered, and knocking is suppressed quickly.

  On the other hand, the cooling water that has flowed toward the bypass passage 54 and bypasses the cylinder heads 12L and 12R is returned to the radiator 46 as it is. In a state where the flow path switching valve 44 is switched to the bypass passage 54 side, the cooling water circulates repeatedly through the radiator 46 and the second pump 42 without passing through the high temperature region. Therefore, the cooling water is cooled by repeatedly releasing heat and maintained at a low temperature.

  The flow path switching valve 44 is basically switched so that the discharge port of the second pump 42 communicates with the cylinder heads 12L and 12R when the engine is in the knocking region, and the coolant is supplied to the cylinder heads 12L and 12L. Flowed to the 12R side. However, when the radiator temperature detected by the temperature sensor 52 provided in the radiator 46 exceeds a predetermined threshold, the discharge port of the second pump 42 is switched to communicate with the bypass passage 54 side. As a result, the cooling water circulates around the cylinder heads 12L and 12R to be in a low temperature state.

  In the present embodiment, when the flow path switching valve 44 is energized, the discharge port of the second pump 42 communicates with the cylinder heads 12L and 12R, and when the flow path switching valve 44 is not energized, the second pump 42 is connected. The discharge port communicates with the bypass passage 54 side.

(Control device)
FIG. 2 is a functional block diagram showing the configuration of the control device 200 provided in the engine cooling control device 100 according to the present embodiment. FIG. 2 shows a part related to the control of the second pump 42 and the flow path switching valve 44 provided in the second cooling water circulation path 40 in the configuration of the control device 200. The control device 200 is mainly configured by a known microcomputer, and includes a knocking region determination unit 210, a radiator temperature detection unit 220, a pump control unit 230, and a flow path switching valve control unit 240. Specifically, each of these units is realized by executing a software program by a microcomputer.

  The control device 200 includes a storage element (not shown) such as a RAM (Random Access Memory) and a ROM (Read Only Memory). The control device 200 can read information related to the engine speed Ne, the intake air amount Va, the EGR amount Ve, the radiator temperature Trad, and the like.

  Knocking area determination unit 210 determines whether or not the engine operating state is in a knocking area where knocking may occur. In the present embodiment, knocking region determination unit 210 determines whether or not the engine operating state is in the knocking region by determining the presence or absence of knocking based on the amount of change in engine speed Ne. However, another method may be used for determining whether or not the engine operating state is in the knocking region.

  The radiator temperature detector 220 reads the sensor signal of the temperature sensor 52 provided in the radiator 46 and detects the radiator temperature Trad. Thereby, the temperature of the cooling water circulating through the second cooling water circulation path 40 is grasped.

  The pump control unit 230 performs drive control of the second pump 42 based on the determination result of the knocking region determination unit 210 and the radiator temperature Trad. In the present embodiment, the second pump 42 is driven with a constant output, and the pump control unit 230 switches driving or stopping of the second pump 42.

  The channel switching valve control unit 240 controls the channel switching valve 44 based on the determination result of the knocking region determination unit 210 and the radiator temperature Trad. In the present embodiment, the flow path switching valve controller 240 energizes the flow path switching valve 44 when circulating the cooling water through the second cooling water circulation path 40 while passing the water jacket of the cylinder heads 12L, 12R. Let Thereby, the discharge port of the second pump 42 communicates with the cylinder heads 12L and 12R. The flow path switching valve controller 240 stops energization of the flow path switching valve 44 when circulating the cooling water in the second cooling water circulation path 40 while bypassing the water jacket of the cylinder heads 12L, 12R. To do. Thereby, the discharge port of the second pump 42 communicates with the bypass passage 54 side.

<< 2. Example of engine cooling control method >>
Next, an example of an engine cooling control method executed by the control device 200 of the engine cooling control device 100 according to the present embodiment will be described. FIG. 3 is a flowchart illustrating an example of an engine cooling control method. The following control is always executed, for example, during engine operation. Note that this control is to control the flow of the cooling water in the second cooling water circulation path 40, and the first pump 22 is always in the first cooling water circulation path 20 while the control is executed. Circulates the cooling water.

  First, in step S10, the control device 200 determines whether or not the radiator temperature Trad detected by the temperature sensor 52 provided in the radiator 46 is equal to or lower than a preset threshold value Trad_0. When the radiator temperature Trad exceeds the threshold value Trad_0 (S10: No), it is necessary to reduce the temperature of the cooling water circulating through the second cooling water circulation path 40, so the control device 200 proceeds to step S30, The second pump 42 is driven while energization to the flow path switching valve 44 is stopped. The threshold value Trad_0 can be set to 75 ° C., for example.

  Thereby, the cooling water pumped by the second pump 42 bypasses the water jacket of the cylinder heads 12L and 12R and returns to the second pump 42 via the bypass passage 54 and the radiator 46. Accordingly, the cooling water repeatedly passes through the radiator 46 and is brought into a low temperature state by repeatedly releasing heat.

  On the other hand, when the radiator temperature Trad is equal to or lower than the threshold value Trad_0 (S10: Yes), the control device 200 determines in step S20 whether or not the operating state of the engine is in the knocking region. In the present embodiment, the control device 200 determines whether or not knocking has occurred depending on whether or not the fluctuation amount ΔNe of the engine speed Ne per unit time is greater than or equal to a predetermined threshold value ΔNe_0 set in advance.

  When the engine operating state is not in the knocking region (S20: No), there is no need to increase the flow rate of the cooling water that passes through the cylinder heads 12L and 12R. Accordingly, the control device 200 proceeds to step S50, stops energization of the flow path switching valve 44, and stops the driving of the second pump 42. Thereby, the 2nd cooling water circulation path 40 is maintained in the state where the flow of cooling water stopped.

  On the other hand, when the engine operating state is in the knocking region (S20: Yes), it is necessary to lower the combustion temperature of the fuel in the combustion chamber. Therefore, the control device 200 proceeds to step S40, drives the second pump 42, and energizes the flow path switching valve 44. As a result, the discharge port of the second pump 42 is communicated with the cooling water passages 56L and 56R. Then, the cooling water pumped by the second pump 42 returns to the second pump 42 via the cooling water passages 56L and 56R, the water jackets of the cylinder heads 12L and 12R, the cooling water passage 58, and the radiator 46.

  As a result, the cylinder heads 12L and 12R are pumped by the first pump 22 and are pumped by the second pump 42 together with the cooling water flowing through the first cooling water circulation path 20 to circulate the second cooling water. Cooling water flowing in the path 40 flows. Therefore, the cooling efficiency of the cylinder heads 12L and 12R is improved, and the temperature of the cylinder heads 12L and 12R, that is, the combustion temperature is lowered early, so that the knocking that has occurred is suppressed.

  In the above flowchart, when the engine operating state is not in the knocking region and the radiator temperature Trad is equal to or lower than the threshold value Trad_0 (S10: Yes and S20: No), the second cooling water circulation path 40 Cooling water circulation is stopped. However, also in this case, the process may proceed to step S30, and the cooling water may bypass the cylinder heads 12L and 12R and repeatedly pass through the radiator 46. That is, step S50 may be omitted.

  In the case of such control, the cooling water circulates through the radiator 46 at all times during a period in which the cooling water in the second cooling water circulation path 40 does not pass through the cylinder heads 12L and 12R. Therefore, not only the cooling water in the radiator 46 but also the cooling water circulating through the second pump 42, the flow path switching valve 44, the bypass passage 54, and the water tank 48 is maintained at a low temperature uniformly. Therefore, when the cylinder heads 12L and 12R need to be cooled, low-temperature cooling water can be stably supplied to the water jackets of the cylinder heads 12L and 12R.

(Other control examples)
The control device 200 may execute the above cooling control using a control map instead of executing the cooling control according to the flowchart of FIG. FIG. 4 shows an example of a usable control map. In such a control map, the on / off state of the second pump 42 and the on / off state of the flow path switching valve 44 are determined in advance depending on whether the engine operating state is in the knocking region and whether the radiator temperature Trad is equal to or lower than the threshold value Trad_0. Is set.

  For example, the control device 200 detects the fluctuation amount ΔNe of the engine speed Ne and the radiator temperature Trad, and refers to the control map to determine whether the second pump 42 and the flow path switching valve 44 are turned on or off. When controlling according to the control map, low-temperature cooling water is supplied from the second cooling water circulation path 40 when the operating state of the engine is in the knocking region and the radiator temperature Trad is equal to or lower than the threshold value Trad_0. Therefore, the cooling water flowing in the second cooling water circulation path 40 flows together with the cooling water flowing in the first cooling water circulation path 20 to the cylinder heads 12L and 12R, and the cylinder heads 12L and 12R efficiently To be cooled.

  When the control is performed according to the control map, the circulation of the cooling water in the second cooling water circulation path 40 is stopped when the operating state of the engine is not in the knocking region and the radiator temperature Trad is equal to or lower than the threshold value Trad_0. Further, when the control is performed according to the control map, when the radiator temperature Trad exceeds the threshold value Trad_0, regardless of whether or not the operating state of the engine is in the knocking region, the cylinder heads 12L and 12R are bypassed, It circulates in the second cooling water circulation path 40. Accordingly, the cooling water in the second cooling water circulation path 40 is maintained at a low temperature.

  As described above, according to the present embodiment, while the engine is operating while cooling the cylinder heads 12L, 12R and the cylinder blocks 14L, 14R with the cooling water circulating in the first cooling water circulation path 20. When the combustion temperature of the engine rises and knocking is likely to occur, the cooling water circulating through the second cooling water circulation path 40 is supplied to the cylinder heads 12L and 12R. Accordingly, the flow rate of the cooling water passing through the cylinder heads 12L and 12R increases, and the cylinder heads 12L and 12R are efficiently cooled. As a result, the combustion temperature of the engine decreases, and the knocking that has occurred is suppressed.

  Further, according to the present embodiment, the temperature of the cooling water circulating through the second cooling water circulation path 40 is low even during the period when the cooling water in the second cooling water circulation path 40 is not supplied to the cylinder heads 12L, 12R. To be maintained. Therefore, when the combustion temperature of the engine rises and knocking occurs, low-temperature cooling water can be quickly supplied to the cylinder heads 12L and 12R. Thereby, the temperature of the cylinder heads 12L and 12R can be lowered at an early stage, and knocking occurring can be suppressed.

  The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to such examples. It is obvious that a person having ordinary knowledge in the technical field to which the present invention pertains can make various modifications or application examples within the scope of the technical idea described in the claims. Of course, it is understood that these also belong to the technical scope of the present invention.

  For example, in the above embodiment, the output of the second pump 42 is constant, and the control device 200 controls only on / off of the second pump 42, but this control is not limited to this example. The control device 200 may variably control the output of the second pump 42 according to the variation amount ΔNe of the engine speed Ne. That is, as the fluctuation amount ΔNe of the engine speed Ne is larger, the degree of abnormal combustion in the combustion chamber is severer and the combustion temperature is estimated to be higher. Therefore, the output of the second pump 42 is increased and cooling is performed. You may make it increase the flow volume of water.

  Further, in the above embodiment, the control for cooling the cylinder heads 12L, 12R with the cooling water circulating in the second cooling water circulation path 40 is executed. However, the control device of the above embodiment has the cylinder head 12L, You may use for control which warms 12R. For example, the second cooling water circulation path 40 in the engine cooling control apparatus 100 is completely separated from the first cooling water circulation path 20 to be a separate flow path, and the radiator 46 is replaced with a heating device or the like. Then, when the combustion temperature of the engine is lowered and a surge is likely to occur, a high-temperature medium is circulated in the second circulation path so as to pass through the cylinder heads 12L and 12R. Thereby, the temperature of the cylinder heads 12L, 12R rises, the combustion temperature of the engine rises, and the generated surge is suppressed.

12L, 12R Cylinder head 14L, 14R Cylinder block 16L, 18L, 16R, 18R Cooling water passage 20 First cooling water circulation passage 20a, 20b Cooling water passage 22 First pump 24L, 24R Water separation chamber 26L, 26R Water collecting chamber 28 Collecting pipe 30 Radiator 32 Thermostat valve 40 Second cooling water circulation path 42 Second pump 44 Flow path switching valve 46 Radiator 48 Water tank 52 Temperature sensor 54 Bypass path 56L, 56R Cooling water path 58 Cooling water path 62 EGR valve 64 Throttle chamber 66 Thermostat valve 68 Transmission heat exchanger 72 Heater cock 74 Heater core 76 Bottom bypass valve 100 Engine cooling control device 200 Control device 210 Knocking area determination unit 220 Radiator temperature detection Outlet 230 Pump control unit 240 Flow path switching valve control unit

Claims (2)

A first coolant circulation path that passes through the cylinder head and cylinder block of the engine;
A first pump for circulating cooling water in the first cooling water circulation path;
A first cooling device for cooling the cooling water circulating in the first cooling water circulation path;
A second coolant circulation path that passes through the cylinder head of the engine;
A second pump for circulating cooling water in the second cooling water circulation path;
A second cooling device for cooling the cooling water circulating in the second cooling water circulation path;
A bypass passage branched from the second pump downstream side of the second cooling water circulation path and upstream of the cylinder head to join the upstream side of the second cooling device;
A flow path switching valve provided at a branch position of the bypass passage and communicating the discharge port of the second pump to the cylinder head side or the bypass passage side;
A control device for controlling the second pump and the flow path switching valve,
The control device includes:
When the operating state of the engine is in the knocking region,
When the temperature of the cooling water in the second cooling water circulation path is less than a predetermined threshold, the discharge port of the second pump is communicated to the cylinder head side by the flow path switching valve, and the cylinder While circulating the cooling water through the head,
The second when the temperature of the cooling water of the cooling water circulation path is equal to or greater than the predetermined threshold, communicates the discharge port of the second pump in the bypass passage side by the flow path switching valve, the Ru lowers the temperature of the cooling water by circulating the cooling water through the bypass passage without passing through the cylinder head, the engine cooling control unit. When the temperature of the cooling water in the second cooling water circulation path is lower than a predetermined threshold value and the operating state of the engine is not in the knocking region, the control device uses the flow path switching valve to The engine cooling control device according to claim 1, wherein a discharge port of a second pump communicates with the bypass passage side.

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