JP5958150B2 - Engine cooling system - Google Patents

Description

  The present invention provides a first flow path through which cooling water from an engine flows via a radiator, a second flow path through which cooling water from the engine flows around the radiator, and the first flow path A flow path portion downstream of the radiator and the second flow path merge, a merge flow path located downstream from the merge section and communicating with the engine, and cooling water in the merge flow path is returned to the engine. A circulating pump, a temperature sensing part heated by cooling water in the junction, and a valve body that opens and closes the junction of the first flow path to the junction according to the heating state of the temperature sensing part. The present invention relates to an engine cooling device including a thermostat valve.

In the engine cooling device, for example, in an operation state where the coolant temperature is low, such as warm-up operation after starting the engine, the joining portion to the joining portion of the first flow path is closed by the valve body of the thermostat valve, and the radiator is Only the cooling water of the second flow path that bypasses is allowed to flow into the merging portion and recirculate to the engine.
Then, the confluence portion is opened by heating the temperature sensing part as the cooling water temperature rises. For example, in the operation state where the cooling water temperature is high after the warm-up operation is finished, the cooling water in the first flow path and the second flow path is used. It flows into the combined flow path from the merging portion and returns to the engine.
The conventional engine cooling device is configured such that the cooling water in the first flow path can flow into the merge path only through the merge portion to the merge section of the first flow path (see, for example, Patent Document 1).

JP 2010-180779 A

Since the temperature sensing part of the thermostat valve is gradually heated by the cooling water in the merging part, the valve body that opens the merging part to the merging part of the first flow path is moved to the valve opening side as the cooling water temperature rises. Move gradually.
For this reason, the cooling water flow rate of the 1st flow path which passes a radiator increases gradually as a valve body moves to the valve opening side.
Therefore, for example, even when the coolant temperature rapidly rises due to a sudden increase in engine load and the coolant flow rate passing through the radiator is to be increased quickly, a time lag occurs until the valve element moves to the maximum valve opening position, and the timing is good. There is a possibility that it cannot be increased.

In order to reduce the time lag, for example, it is conceivable to set the cooling water temperature (valve opening temperature) at which the temperature sensing unit starts the movement of the valve body to be low.
However, in this case, the cooling water temperature in a normal operation state where the engine load does not rapidly increase may be unnecessarily lowered, resulting in problems such as deterioration in fuel consumption and increase in air pollutants in the exhaust gas.

  The present invention has been made in view of the above circumstances, and adopts a simple configuration that allows the cooling water in the first flow path to flow into the combined flow path by the operation of a thermostat valve in accordance with the cooling water temperature. An object of the present invention is to provide an engine cooling device capable of increasing the flow rate of the coolant passing therethrough in a timely manner.

FEATURES configuration of the engine cooling system according to the present invention, the second flow path and the first flow path through which cooling water from the engine flows through the radiator, the cooling water from the engine flows while bypassing the radiator A flow path portion downstream of the radiator in the first flow path and the second flow path merge, a merge flow path positioned downstream from the merge portion and communicating with the engine, and the merge flow path A circulating pump that recirculates the cooling water to the engine, a temperature sensing part that is heated by the cooling water in the joining part, and a joining part to the joining part of the first flow path according to the heating state of the temperature sensing part A thermostat valve having a valve body that opens and closes, a bypass channel that branches from a portion of the first channel downstream of the radiator, bypasses the thermostat valve, and communicates with the combined channel, and the bypass Flow A bypass valve which can open and close the, and a control unit for controlling the opening and closing operation of the bypass valve, the control unit may pre-set lower than the second temperature at which the temperature of the cooling water is opened said thermostat valve The bypass valve is opened when the temperature reaches the first temperature, and the bypass valve is closed when the temperature of the cooling water exceeds the second temperature .

  The engine cooling device of this configuration branches from a portion of the first flow path downstream of the radiator, bypasses the thermostat valve and communicates with the combined flow path, and opens and closes the bypass flow path A possible bypass valve, and a controller for controlling the opening and closing operation of the bypass valve.

For this reason, by opening the bypass valve as necessary, the coolant in the first flow path bypasses the thermostat valve and flows into the combined flow path from the bypass flow path, and the flow rate of the coolant passing through the radiator is increased. Can be made.
In addition, since the bypass flow channel causes the cooling water in the first flow channel to flow into the merge channel located downstream from the merge unit that heats the temperature sensing unit, the coolant from the bypass channel heats the temperature sensing unit. Low risk of lowering temperature.
For this reason, there is little possibility that the speed which a valve body opens a junction part falls, and the inflow of the cooling water from a junction part to a junction part is inhibited.
Further, when the temperature of the cooling water reaches a first preset temperature lower than the second temperature at which the thermostat valve opens, the bypass valve is opened, so that the thermostat valve opens the cooling water in the first flow path. It is possible to positively increase the flow rate of the cooling water that flows into the combined flow path before passing through the radiator. Further, when the temperature of the cooling water becomes equal to or higher than the second temperature, the thermostat valve is opened. Therefore, by closing the bypass valve, the entire amount of the cooling water in the first flow path is caused to flow into the merging portion through the merging portion. The flow state of the first flow path can be adjusted by the thermostat valve. In order to optimally exert the adjustment function of the thermostat valve, it is preferable to close the bypass valve when the temperature is equal to or higher than the second temperature.
Therefore, with the engine cooling device of this configuration, the cooling that passes through the radiator while adopting a simple configuration that allows the cooling water in the first flow path to flow into the combined flow path by the operation of the thermostat valve according to the cooling water temperature. The water flow rate can be increased in a timely manner.

Another characteristic configuration is that the control unit is configured to open the bypass valve when the temperature of the cooling water reaches or exceeds a third temperature that is an allowable upper limit temperature.

  With this configuration, when the cooling water temperature rises greatly in a state where the cooling water in the first channel flows into the merging portion through the merging portion, a part of the cooling water in the first channel is bypassed. The flow rate of the cooling water passing through the radiator is increased by flowing into the combined flow path through the radiator, so that the cooling capacity of the radiator can be improved.

According to another characteristic configuration, the control unit is configured to operate the circulation pump based on a control map set in advance according to each state when the bypass valve is in an open state or a closed state. It is in a certain point.

  According to this configuration, the circulation pump is set in accordance with the open state of the bypass valve in which the flow rate of the coolant passing through the radiator is likely to increase and the closed state of the bypass valve in which the flow rate of the coolant passing through the radiator is likely to be reduced. Can operate properly.

Another characteristic configuration is that the maximum output of the circulation pump in the opened state of the bypass valve is set smaller than the maximum output of the circulation pump in the closed state of the bypass valve.

  If it is this structure, the rapid fall of the cooling water temperature resulting from the increase in the discharge amount of the circulation pump in the valve open state of a bypass valve can be prevented.

According to another characteristic configuration, the control unit predicts a cooling water temperature after a predetermined time has elapsed from a current time based on a rise in the cooling water temperature after starting the engine, and the current cooling water temperature is determined by the thermostat valve. The bypass valve is configured to open when the predicted temperature is higher than the third temperature, which is the allowable upper limit temperature, when the temperature is lower than the second temperature at which the valve is opened.

  With this configuration, the flow rate of the coolant passing through the radiator is increased in a timely manner based on the actual rise in the coolant temperature after the engine is started, preventing the coolant temperature from rising beyond the allowable upper limit temperature. can do.

According to another characteristic configuration, the control unit calculates a predicted reaching temperature of the cooling water based on an output result after starting the engine, and a current cooling water temperature is higher than a second temperature at which the thermostat valve opens. When the temperature is low, the bypass valve is configured to open when the predicted temperature reaches a third temperature that is the allowable upper limit temperature.

  With this configuration, the flow rate of the coolant passing through the radiator can be increased in a timely manner based on the output performance after the engine is started, and the situation where the coolant temperature rises beyond the allowable upper limit temperature can be prevented. .

It is a cooling circuit diagram of an engine cooling device. It is a mimetic diagram showing the inside of a thermostat device in the state where both a thermostat valve and a bypass valve are closed. It is a mimetic diagram showing the inside of a thermostat device in the state where a thermostat valve was closed and a bypass valve was opened. It is a mimetic diagram showing the inside of a thermostat device in the state where a thermostat valve was opened and a bypass valve was closed. It is a schematic diagram which shows the inside of a thermostat apparatus in the state in which both a thermostat valve and a bypass valve were open. It is a graph which shows the control map of a circulation pump. It is a flowchart which shows the control action by a control part. It is a flowchart which shows the control action by the control part of 2nd Embodiment. It is a time chart explaining the prediction method of cooling water temperature. It is a graph explaining the setting method of predetermined temperature. It is a flowchart which shows the control action by the control part of 2nd Embodiment. It is a time chart explaining the calculation method of predicted arrival temperature.

Embodiments of the present invention will be described below with reference to the drawings.
[First Embodiment]
FIG. 1 shows a cooling circuit diagram of an engine cooling device B according to the present invention for cooling a cylinder block A1 and a cylinder head A2 of an automobile engine (internal combustion engine) A.

  The engine cooling device B includes a radiator 3 for cooling the cooling water of the engine A, a first flow path 1 through which the cooling water from the engine A flows via the radiator 3, and a cooling water from the engine A for the radiator 3 A thermostat device C that mixes and mixes the second flow path 2 that bypasses and flows the cooling water of the first flow path 1 and the second flow path 2 in accordance with the cooling water temperature thw, and the thermostat apparatus C. A circulation pump 5 that recirculates the passed cooling water to the engine A and a control unit 6 that controls the operation of the circulation pump 5 are provided.

  The radiator 3 is connected in the middle of the first flow path 1. A heat transfer device 7 having a heat exchanger such as a heater core heated by the cooling water of the engine A and an EGR cooler cooled by the cooling water of the engine A is connected in the middle of the second flow path 2.

In this embodiment, the circulation pump 5 is constituted by an electric water pump capable of changing the discharge force (discharge amount) without depending on the engine speed, but is constituted by a mechanical variable water pump. May be.
The circulation pump 5 press-fits cooling water into an engine inlet of a water jacket (not shown) formed in the cylinder block A1.
Cooling water that has been press-fitted into the engine inlet and passed through the water jacket of the cylinder block A1 passes through a water jacket (not shown) formed in the cylinder head A2, and passes from the engine outlet to the first flow path 1 and the second flow path. 2 is circulated in a state of being sucked into the circulation pump 5 via the thermostat device C.

The thermostat device C includes a resin valve unit 4 equipped with a thermostat valve 8 and a bypass valve 9 as shown in FIGS.
In addition to the operation of the circulation pump 5, the control unit 6 controls the opening / closing operation of the bypass flow path 12 by the bypass valve 9 according to the operating state of the engine A.

FIG. 2 shows the thermostat device C in which the thermostat valve 8 and the bypass valve 9 are closed, and only the cooling water of the second flow path 2 flows into the merge section 10 and flows into the circulation pump 5 from the merge path 11. .
FIG. 3 shows a thermostat device C in which the thermostat valve 8 is closed and the bypass valve 9 is open. The cooling water in the first flow path 1 from the bypass flow path 12 and the second flow from the junction 10 are shown. The cooling water in the passage 2 joins in the joint passage 11 and flows into the circulation pump 5.
FIG. 4 shows the thermostat device C in which the thermostat valve 8 is in the open state and the bypass valve 9 is in the closed state, and the cooling water in the first flow path 1 and the cooling water in the second flow path 2 from the merging portion 1b. It merges at the merge unit 10 and flows into the circulation pump 5 from the merge channel 11.
FIG. 5 shows the thermostat device C in which the thermostat valve 8 and the bypass valve 9 are opened, and the cooling water of the first flow path 1 and the cooling water of the second flow path 2 from the joining portion 1 b and the bypass flow path 12. However, it flows into the circulation pump 5 from the combined flow path 11.
The bypass channel 12 is formed with a smaller diameter than the combined channel 11.

The valve unit 4 includes a first connection path 1 a connected to the downstream side of the first flow path 1, a second connection path 2 a connected to the downstream side of the second flow path 2, and a radiator among the first flow paths 1. 3, a large-diameter merge portion 10 where the downstream flow path portion and the second flow path 2 merge via the first connection path 1 a and the second connection path 2 a, and the engine located downstream from the merge section 10. A combined flow path 11 that communicates with A, and a bypass flow path 12 that is branched from a portion of the first flow path 1 downstream of the radiator 3 and that bypasses the thermostat valve 8 and communicates with the combined flow path 11. Yes.
The merge channel 11 is formed with a smaller diameter than the merge portion 10. The bypass flow path 12 causes the cooling water of the first connection path 1 a to flow into the combined flow path 11 bypassing the thermostat valve 8.
The circulation pump 5 recirculates the cooling water that has passed through the combined flow path 11 to the engine A.

The thermostat valve 8 is fixed to one end side of the temperature sensing part 8a, which is heated and cooled by the cooling water in the joining part 10 and expands and contracts, and is fixed to one end side of the temperature sensing part 8a. A valve body 8b for opening and closing the joining portion 1b to the joining portion 10 via the first connection path 1a, a holding member 8c for holding the other end of the temperature sensing portion 8a at a fixed position in the joining portion 10, and a valve body A guide rod 8d that guides the moving direction of 8b and a compression coil spring 8e that urges the valve body 8b to move toward the side of closing the joining portion 1b.
The guide rod 8d is disposed so as to enter the inside of the first connection path 1a through the joining portion 1b. The compression coil spring 8e is mounted between the valve body 8b and the holding member 8c.

A thermal expansion body such as wax that changes in volume according to the temperature of the cooling water is accommodated in the temperature sensing portion 8a.
As shown in FIGS. 4 and 5, the valve body 8 b is contracted by heating of the temperature sensing portion 8 a, moves to the side where the joining portion 1 b is opened against the urging force of the compression coil spring 8 e, and the temperature sensing portion 8 a As shown in FIGS. 2 and 3, due to the extension by cooling, the joining portion 1b is moved to the closing side, and the joining portion 1b is sealed by the urging force of the compression coil spring 8e.

A bypass valve 9 made up of a normally closed electromagnetic valve that opens the bypass flow path 12 when energized is mounted in the middle of the bypass flow path 12.
The control unit 6 uses the coolant temperature thw at the engine outlet as the coolant temperature T1 when the bypass valve 9 opens (first temperature: hereinafter referred to as bypass valve open temperature) T1 and the valve body 8b of the thermostat valve 8. Is stored in advance in the memory with a coolant temperature (second temperature: hereinafter referred to as a thermostat valve opening temperature) T2 and a permissible upper limit temperature (third temperature) T3 of the engine water temperature. doing.
The bypass valve opening temperature T1 is preset to a temperature lower than the thermostat valve opening temperature T2.

  As shown in FIG. 4, when the thermostat valve 8 is open and the bypass valve 9 is closed, the cooling water of the first flow path 1 that has passed through the radiator 3 flows into the merge path 11 only from the merge portion 1b. Therefore, the cooling water temperature thw is likely to rise.

  Further, as shown in FIG. 5, when the thermostat valve 8 and the bypass valve 9 are in the open state, the cooling water of the first flow path 1 that has passed through the radiator 3 is merged from the merge portion 1 b and the bypass flow path 12. 11, the flow rate of the cooling water passing through the radiator 3 increases and the cooling water temperature thw tends to decrease. The timing at which these states are changed will be described later.

For this reason, as shown in FIG. 6, the control maps M1 and M2 of the circulation pump 5 set in advance according to the respective states when the bypass valve 9 is in the open state and when the bypass valve 9 is in the closed state are stored in the memory. Is remembered.
The control maps M1 and M2 set the correlation between the coolant temperature thw at the engine outlet and the output of the circulation pump 5.
In FIG. 6, a control map M1 is a control map when the bypass valve 9 is in the closed state, and a control map M2 is a control map when the bypass valve 9 is in the open state.

That is, the control unit 6 operates the circulation pump 5 with a constant start output until the cooling water temperature thw reaches the bypass valve opening temperature T1.
Then, after reaching the bypass valve opening temperature T1, the circulation pump 5 is operated based on the control maps M1 and M2 corresponding to the closed state and the opened state of the bypass valve 9, respectively.

  In the control map M1 corresponding to the closed state of the bypass valve 9, the circulation pump 5 is operated at a constant start output until the cooling water temperature thw reaches the bypass valve opening temperature T1, and the cooling water temperature thw is opened. When the valve temperature T1 is reached, the circulation pump 5 is operated while increasing the output at a constant increase rate so that the maximum output M1max is 100% when the allowable upper limit temperature T3 is reached.

On the other hand, in the control map M2 corresponding to the open state of the bypass valve 9, the operation of the circulation pump 5 with a constant start output is maintained even after the coolant temperature thw reaches the bypass valve open temperature T1. When the coolant temperature thw reaches the thermostat valve opening temperature T2, the circulating pump 5 is operated while increasing the output at a constant increase rate so that the maximum output M2max is less than 100% when the allowable upper limit temperature T3 is reached. To do.
Therefore, the maximum output M2max of the circulation pump 5 when the bypass valve 9 is open is set smaller than the maximum output M1max of the circulation pump 5 when the bypass valve 9 is closed.

Control operations by the control unit 6 of the circulation pump 5 and the bypass valve 9 will be described with reference to the flowchart of FIG.
When engine A is started, in order to perform warm-up operation, as shown in FIG. 2, the bypass valve 9 is closed (step # 1), and the circulation pump 5 is operated with a constant start output according to the control map M1. Start (step # 2).

When the coolant temperature thw becomes equal to or higher than the bypass valve opening temperature T1, the bypass valve 9 is opened as shown in FIG. 3 (steps # 3 and 4), and the operation shifts to the operation of the circulation pump 5 based on the control map M2 ( Step # 5), maintaining the operation of the circulation pump 5 with a constant start output.
Therefore, it is possible to increase the flow rate of the cooling water passing through the radiator 3 by causing the cooling water in the first flow path 1 to bypass the thermostat valve 8 and flow into the combined flow path 11 from the bypass flow path 12.

When the coolant temperature thw becomes equal to or higher than the thermostat valve opening temperature T2, the bypass valve 9 is closed as shown in FIG. 4 (steps # 6 and 7), and the operation returns to the operation of the circulation pump 5 by the control map M1. (Step # 8).
That is, the output is increased from the output corresponding to the thermostat valve opening temperature T2 in the control map M1 to a maximum output M1max of 100% at a constant increase rate.

  When the cooling water temperature thw is equal to or higher than the thermostat valve opening temperature T2, the bypass valve 9 is closed and the thermostat valve 8 is opened, so that the total amount of the cooling water in the first flow path 1 is joined through the joining portion 1b. 10, the flow state of the first flow path 1 is adjusted by the thermostat valve 8. In order to optimally exert the adjustment function of the thermostat valve 8, it is preferable to close the bypass valve 9 when the thermostat valve opening temperature T2 or higher.

When the cooling water temperature thw reaches the allowable upper limit temperature T3 (step # 9), the bypass valve 9 is opened as shown in FIG. 5 (step # 10), and the flow rate of the cooling water passing through the radiator 3 is increased. To prevent an excessive increase in the temperature of the cooling water.
Therefore, when the cooling water temperature thw rises greatly with the cooling water in the first flow path 1 flowing into the merge section 10 through the merge portion 1b, a part of the cooling water in the first flow path 1 is bypassed. It flows into the combined flow path 11 through the path 12. Therefore, the cooling water flow rate which passes the radiator 3 can be increased, and the cooling capacity by the radiator 3 can be improved.

[Second Embodiment]
FIG. 8 is a flowchart showing another embodiment of the control operation by the control unit 6.
In the present embodiment, when the cooling water temperature thw is lower than the thermostat valve opening temperature T2 (step # 20), as shown in FIG. 9, based on the rise record of the cooling water temperature thw after the start of the engine A, A cooling water temperature (hereinafter referred to as a predicted cooling water temperature) T4 after the current time TM0 is predicted.

  Specifically, the predicted cooling water temperature T4 at the time TM1 when the predetermined time t1 has elapsed from the current time TM0 is obtained, and when the predicted cooling water temperature T4 becomes higher than the allowable upper limit temperature T3, the bypass at the current time TM0. The valve 9 is opened (steps # 21 and 22, FIG. 3).

  In the first embodiment, the bypass valve 9 is closed when the cooling water temperature thw reaches the thermostat valve opening temperature T2, but in this embodiment, the cooling water temperature thw exceeds the allowable upper limit temperature T3. The valve is opened when it is calculated that there is a possibility. Therefore, the actual bypass valve opening temperature T1 when the bypass valve 9 is opened is not constant.

As a result, it becomes a problem at what timing the bypass valve 9 once opened is closed.
If the bypass valve 9 is set to be closed when the coolant temperature thw reaches the thermostat valve opening temperature T2, the coolant temperature thw when the bypass valve 9 is opened is relatively low. The temperature difference between the temperature and the thermostat valve opening temperature T2 becomes large.

However, since the degree to which the coolant temperature thw rises is mitigated by opening the bypass valve 9, it may take a long time for the coolant temperature thw to actually rise to the thermostat valve opening temperature T2. .
As a result, an increase in the engine temperature is suppressed, and there is a case where the warm-up operation cannot be completed early.

  Therefore, in this embodiment, when it is calculated that the above-described allowable upper limit temperature T3 is exceeded, the bypass valve 9 is closed based on the time predicted to reach the thermostat valve opening temperature T2. That is, the bypass valve 9 is closed at time t2 when the broken line indicating the predicted cooling water temperature T4 in FIG. 9 becomes the thermostat valve opening temperature T2 (steps # 23 and 24).

  That is, as shown in FIG. 9, the water temperature slope (water temperature increase rate in the past predetermined time) dthw / dt at the current time TM0 is calculated based on the change over time of the coolant temperature thw up to the current time TM0. Assuming that the cooling water temperature thw after the current time TM0 rises at the water temperature gradient dthw / dt, the cooling water temperature thw at the current time TM0 and the elapsed time t from the current time TM0 are added to the water temperature gradient dthw / dt. A temperature (thw + (dT / dt) × t) obtained by adding the multiplied temperature rise (dT / dt) × t is set as a predicted cooling water temperature T4.

  As shown in FIG. 10, the predetermined time t1 is equal to the cooling water temperature thw at the current time TM0 and the magnitude of the water temperature gradient dthw / dt, even if the cooling water temperature thw is the same, the water temperature gradient dthw / dt. The larger the is, the shorter the predetermined time t1 is set.

  That is, the correlation between the cooling water temperature thw at the current time TM0 and the predetermined time t1 is preset according to the magnitude of the water temperature gradient dthw / dt, and the cooling water temperature thw corresponding to the calculated water temperature gradient dthw / dt. And the predetermined time t1 is set using the correlation between the predetermined time t1 and the predetermined time t1.

Thus, by opening the bypass valve 9 according to the relationship between the inclination of the coolant temperature thw and the allowable upper limit temperature T3, it is possible to reliably prevent the coolant temperature thw from exceeding the allowable upper limit temperature T3. . In the present invention, the rise of the coolant temperature thw is calculated before the thermostat valve 8 is opened, and the bypass valve 9 is opened prior to the opening of the thermostat valve 8, so that the coolant temperature thw rises excessively. This is to prevent this from happening.
Other configurations are the same as those of the first embodiment.

[Third Embodiment]
FIG. 11 is a flowchart showing another embodiment of the control operation by the control unit 6.
In the present embodiment, when the current cooling water temperature thw is lower than the thermostat valve opening temperature T2 (step # 30), as shown in FIG. The ultimate temperature T5 is calculated.

  That is, the engine output from the start of the engine A is integrated, and a value (ΣPe × K) obtained by multiplying the engine output integrated value ΣPe by a temperature conversion coefficient (coefficient for converting engine output into temperature) K and the current cooling water A value (thw + ΣPe × K) obtained by adding the temperature thw is set as a predicted arrival temperature T5.

  When the predicted reaching temperature T5 becomes higher than the allowable upper limit temperature T3 of the engine water temperature, the bypass valve 9 is opened as shown in FIG. 3 (steps # 31 and 32), and the engine output integrated value ΣPe is set. When reset (step # 33) and the actual coolant temperature thw reaches the thermostat valve opening temperature T2, the bypass valve 9 is closed as shown in FIG. 4 (steps # 34 and 35).

In the present embodiment, since the predicted reaching temperature T5 of the cooling water is calculated based on the engine output integrated value ΣPe, when the cooling water temperature thw is predicted to exceed the allowable upper limit temperature T3, a predetermined value is given from the engine A. It is scheduled to have a fever. For this reason, the closing timing of the bypass valve 9 in the present embodiment is closed when the cooling water temperature thw actually reaches the thermostat valve opening temperature T2, as shown in FIG.
Other configurations are the same as those of the first embodiment.

[Other Embodiments]
In the engine cooling device according to the present invention, a bypass valve 9 whose flow rate can be adjusted by a command from the control unit 6 may be connected to the bypass flow path 12.

The engine cooling device according to the present invention can be used for cooling various engines.

DESCRIPTION OF SYMBOLS 1 1st flow path 1b Merge part 2 2nd flow path 3 Radiator 5 Circulation pump 6 Control part 8 Thermostat valve 8a Temperature sensing part 8b Valve body 9 Bypass valve 10 Merge part 11 Merge flow path 12 Bypass flow path A Engine M1, M2 control Maps M1max, M2max Maximum output T1 First temperature T2 Second temperature T3 Third temperature (allowable upper limit temperature)
T4 predicted temperature T5 predicted temperature thw Cooling water temperature

Claims (6)

A first flow path through which cooling water from the engine flows through the radiator;
A second flow path in which cooling water from the engine flows around the radiator;
A flow path portion downstream of the radiator in the first flow path and the second flow path merge, and a merge flow path that is located downstream from the merge portion and communicates with the engine;
A circulation pump for recirculating cooling water of the combined flow path to the engine;
A thermostat valve provided with a temperature sensing part heated by cooling water in the joining part, and a valve body that opens and closes a joining part to the joining part of the first flow path according to a heating state of the temperature sensing part;
A bypass channel that branches from a portion of the first channel downstream of the radiator, bypasses the thermostat valve, and communicates with the combined channel;
A bypass valve capable of opening and closing the bypass flow path;
A control unit for controlling the opening and closing operation of the bypass valve ,
The controller opens the bypass valve when the temperature of the cooling water reaches a first preset temperature lower than a second temperature at which the thermostat valve opens, and the temperature of the cooling water is set to the second temperature. An engine cooling device configured to close the bypass valve when the above is reached . 2. The engine cooling device according to claim 1 , wherein the control unit is configured to open the bypass valve when a temperature of the cooling water is equal to or higher than a third temperature that is an allowable upper limit temperature. Wherein, said when the bypass valve is in the open state or closed state, claim based on a control map which is set in advance depending on the state of each is arranged to operate the circulation pump 1 Or the engine cooling device of 2. The maximum output of the circulating pump in the open state of the bypass valve, according to any one of claims 1-3 that is set smaller than the maximum output of the circulating pump in the closed state of the bypass valve Engine cooling device. The control unit predicts a cooling water temperature after a predetermined time has elapsed from the current time based on an actual increase in the cooling water temperature after starting the engine, and the current cooling water temperature is a second temperature at which the thermostat valve opens. lower than in, when the predicted temperature is higher than the third temperature is a permissible upper limit temperature, engine cooling apparatus according to claim 1 which is arranged to open the bypass valve. The control unit calculates a predicted arrival temperature of the cooling water based on an output result after starting the engine, and the prediction is performed when the current cooling water temperature is lower than a second temperature at which the thermostat valve opens. when the temperature reached is higher than the third temperature is a permissible upper limit temperature, engine cooling apparatus according to claim 1 which is arranged to open the bypass valve.

Images