JP2003184556A - Cooling system controller for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve an early warm-up performance by enhancing an engine preheating effect by hot water supplied from a heat accumulator to an engine, and also to improve reliability in the detection of the temperature of cooling water at the time of starting. <P>SOLUTION: When an operator operates an IG switch from an OFF position to an ON position, a bypass valve 19 is closed to shut off a bypass passage 17, a flow control valve 18 is kept in a state in which a passage of a radiator 13 is shut off, and an electric water pump 25 is activated to supply the hot water stored in the heat accumulator 24 into the engine 11 to preheat the engine 11. Then, when the operator starts the engine 11 by operating the IG switch from the ON position to a start position, the electric water pump 25 is turned off and the supply of the hot water into the engine 11 is ended at the time when an engine speed has reached or exceeded a predetermined starting completion speed or at the time when a predetermined time has passed from the start of the supply of the hot water. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling system control device for an internal combustion engine, which is provided with a regenerator for storing cooling water warmed by the internal combustion engine in a heat retaining state and supplying this to the internal combustion engine before the next start. It is about.

[0002]

2. Description of the Related Art In recent years, in an internal combustion engine for a vehicle, in order to improve early warm-up performance at the time of starting to reduce exhaust emission and fuel consumption, when the internal combustion engine is stopped, it is warmed by that time. The cooling water (hot water) collected is collected in the heat storage device, and the hot water in the heat storage device is supplied to the internal combustion engine by the electric pump before the next start to preheat the internal combustion engine, thereby warming up the internal combustion engine early. Have been proposed (Japanese Patent Laid-Open No. 2001-2001
No. 132447).

In addition, in order to prevent the cooling water from the internal combustion engine from flowing to the radiator until the internal combustion engine is warmed up after the start-up, a radiator is installed in the cooling water circulation circuit connecting the internal combustion engine and the radiator. A bypass flow path is provided in parallel, and a thermostat valve that switches the flow of cooling water between the flow path to the radiator and the bypass flow path is provided at the connection between the cooling water circulation circuit and the bypass flow path.
When the temperature of the cooling water is lower than the predetermined temperature corresponding to the completion of warming up, the thermostat valve shuts off the flow passage to the radiator to open the bypass flow passage, and the cooling water from the internal combustion engine is caused to flow to the bypass flow passage. There are things that are made to circulate.

[0004]

However, when hot water is supplied from the heat accumulator to the internal combustion engine before starting, this hot water flows from the internal combustion engine into the cooling water circulation circuit, and the water temperature sensor installed in the cooling water circulation circuit is used. If hot water flows around, the reliability of the detection value of the water temperature sensor at the time of start-up will be reduced. That is, in this case, the water temperature sensor detects the temperature of hot water that is higher than the actual temperature of the internal combustion engine,
Although the actual temperature of the internal combustion engine is still low, it is erroneously detected that the temperature of the internal combustion engine is high. Therefore, if the fuel injection amount is corrected based on the detection value of the water temperature sensor at the time of starting, the injection correction will be performed based on a temperature higher than the actual temperature of the internal combustion engine, and as a result, the fuel injection at the time of starting will be performed. The amount becomes smaller than the appropriate value, the air-fuel ratio at the time of starting shifts to the lean side from the target air-fuel ratio, and the disadvantage that the air-fuel ratio controllability at the time of starting deteriorates occurs.

The present invention is an object of solving the above drawbacks. Therefore, the object of the present invention is to make the water temperature sensor in the cooling water circulation circuit have a higher temperature than the actual temperature of the internal combustion engine at the time of starting. It is an object of the present invention to provide a cooling system control device for an internal combustion engine, which can prevent the detection of the temperature of the hot water and improve the reliability of the detection value of the water temperature sensor at the time of starting.

[0006]

In order to achieve the first object, a cooling system control device for an internal combustion engine according to claim 1 of the present invention is a cooling system for circulating cooling water between the internal combustion engine and a radiator. A water circulation circuit, a bypass flow passage provided so as to bypass the radiator in the cooling water circulation circuit, and cooling water (hereinafter referred to as "hot water") warmed by the internal combustion engine is stored in a heat-retaining state and then stored. When a hot water is supplied from the heat storage device to the internal combustion engine before starting by controlling a heat storage device to be supplied to the internal combustion engine before starting and a valve provided in the cooling water circulation circuit and / or the bypass passage. A cooling water circulation control means for switching the valve to a state in which the flow of cooling water from the internal combustion engine to the bypass flow passage is shut off, and a water temperature sensor for detecting the temperature of cooling water is used as the cooling water circulation circuit. And hot water from the heat accumulator in the cooling water outlet side of the internal combustion engine of are those installed at a position that does not circulate. In this way, when hot water is supplied from the heat storage device to the internal combustion engine before starting, it is possible to prevent the hot water from flowing around the water temperature sensor, so that the water temperature sensor is less than the actual temperature of the internal combustion engine at startup. It is possible to prevent detection of the temperature of hot water of high temperature and improve the reliability of the detection value of the water temperature sensor at the time of starting.

Further, as claimed in claim 2, at the time of starting, the bypass flow passage is opened to allow the cooling water flowing out of the internal combustion engine to flow through the bypass flow passage to be circulated, and at the same time, the cooling water temperature detected by the water temperature sensor at the time of start is set. Based on this, the fuel injection control means may correct the fuel injection amount. That is, when the cooling water flowing out from the internal combustion engine is made to circulate by opening the bypass flow path at the time of starting, the cooling water flowing out from the internal combustion engine can be made to flow around the water temperature sensor. Sometimes, the cooling water temperature corresponding to the actual temperature of the internal combustion engine can be accurately detected by the water temperature sensor.
As a result, if the fuel injection amount is corrected based on the cooling water temperature detected by the water temperature sensor at the time of starting, it is possible to correct the fuel injection amount according to the actual temperature of the internal combustion engine at the time of starting, and The injection amount can be optimized, and the air-fuel ratio controllability at the time of starting can be improved.

According to a third aspect of the present invention, based on the difference between the detected value of the water temperature sensor after a lapse of a predetermined period from the start of hot water supply from the heat storage device to the internal combustion engine and the detected value of the water temperature sensor before the start of hot water supply. The presence / absence of open fixation in which the bypass valve is left open may be determined by the open fixation determination means.
If the bypass valve opens and sticks, the hot water will flow from the internal combustion engine to the vicinity of the water temperature sensor in the cooling water circulation circuit when the hot water is supplied from the heat storage device to the internal combustion engine before starting. As a result, the cooling water temperature detected by the water temperature sensor becomes higher than the actual temperature of the internal combustion engine, and as a result, as the time elapses from the start of hot water supply, the detected value of the water temperature sensor and The difference from the detection value of the water temperature sensor becomes large. From this relationship, whether the difference between the detection value of the water temperature sensor after a certain amount of time has elapsed from the start of the hot water supply and the detection value of the water temperature sensor before the start of the hot water supply is greater than a predetermined open sticking determination value, Whether or not the bypass valve is stuck open can be determined.

In this case, when it is determined that the bypass valve is stuck open, the detected value of the water temperature sensor before the start of hot water supply and after the start until a predetermined period elapses from the start. Estimate the cooling water temperature based on the elapsed time,
It is advisable to correct the fuel injection amount based on the estimated cooling water temperature. If the bypass valve is stuck open, the value detected by the water temperature sensor during startup will be affected by the hot water supplied from the regenerator before startup, and will be higher than the actual internal combustion engine temperature. Therefore, estimating the cooling water temperature based on the detected value of the water temperature sensor before the start of hot water supply and the elapsed time after the start can give a temperature closer to the actual internal combustion engine temperature than the detected value of the water temperature sensor. it can.
Therefore, if the fuel injection amount is corrected based on this estimated cooling water temperature when the bypass valve is stuck open, the fuel injection amount will be greater than when the fuel injection amount is corrected based on the detection value of the water temperature sensor. Can be accurately corrected.

Even when the bypass valve is stuck open, the detected value of the water temperature sensor approaches the actual temperature of the internal combustion engine as the temperature of the internal combustion engine rises with the lapse of time after starting. Therefore, after a lapse of a predetermined period until the temperature difference between the two becomes small to some extent, the fuel injection amount may be corrected using the detection value of the water temperature sensor instead of the estimated cooling water temperature. With this configuration, when the bypass valve is stuck open, the fuel injection amount can be corrected by using the reliable one of the estimated cooling water temperature and the detected value of the water temperature sensor, and the air-fuel ratio can be corrected. It is possible to avoid deterioration of controllability.

In this case, the timing of switching between the estimated cooling water temperature used for correcting the fuel injection amount and the detection value of the water temperature sensor may be determined by the elapsed time after the start, but as in claim 5, When it is determined that the bypass valve is stuck open, the estimated cooling water temperature is used to correct the fuel injection amount until the difference between the estimated cooling water temperature and the detected value of the water temperature sensor after the start is equal to or less than a predetermined value. After that, the fuel injection amount may be corrected using the detection value of the water temperature sensor. With this configuration, even if the temperature rising speed of the internal combustion engine after the start changes due to the operating state of the internal combustion engine after the start, the outside temperature, etc., the cooling used for correcting the fuel injection amount at an appropriate timing accordingly. The water temperature information can be switched from the estimated cooling water temperature to the detection value of the water temperature sensor.

According to a sixth aspect of the present invention, a control valve having a function of switching the flow of the cooling water in the cooling water circulation circuit between the radiator and the bypass passage or a function of controlling the flow rate ratio between the radiator and the bypass passage, and the bypass passage. In a system provided with a bypass valve provided inside, when supplying hot water from the heat storage device to the internal combustion engine, the control valve is maintained in a state of blocking the flow of the cooling water to the radiator, and the bypass valve is It suffices to close the bypass passage by closing the valve. In this case, the control valve may be an electromagnetic valve capable of controlling the flow rate ratio of the cooling water flowing through the radiator and the bypass flow passage, or may be the cooling water flowing between the radiator and the bypass flow passage. A three-way switching valve that switches the flow may be used. In any case, the present invention can be realized by providing a bypass valve in the bypass flow passage.

Further, as described in claim 7, the bypass valve is closed based on the difference between the detected value of the water temperature sensor after a lapse of a predetermined period from the start and the detected value of the water temperature sensor before the start of hot water supply (or at the beginning of start). The presence / absence of closed sticking that is left may be determined by the closed sticking determination means. If the bypass valve closes and sticks, after the engine is started, the flow of cooling water to the bypass passage and radiator is blocked by the bypass valve and control valve, just as during hot water supply to the internal combustion engine. Therefore, even if the internal combustion engine warms up after a certain amount of time has passed since the engine started, the cooling water of the internal combustion engine does not flow around the water temperature sensor in the cooling water circulation circuit, and the detected value of the water temperature sensor Indicates a state in which there is not much change from the detection value of the water temperature sensor before the start of hot water supply (or at the beginning of startup). Therefore, when the bypass valve is closed and stuck, even if the internal combustion engine is actually warmed up, the detected value of the water temperature sensor does not rise to the water temperature corresponding to the completion of warming up.
It was erroneously determined that it was not warmed up, and as a result, even after it was warmed up, the flow path to the radiator was blocked by the control valve, and the increase in the cooling water temperature detected by the water temperature sensor continued to be small. It will be. From this relationship, whether or not the difference between the detection value of the water temperature sensor after a lapse of a predetermined period from the start and the detection value of the water temperature sensor before the start of hot water supply (or at the beginning of the start) is smaller than a predetermined closed sticking determination value, Whether or not the bypass valve is stuck closed can be determined.

In this case, when it is determined that the bypass valve is closed and stuck, the control valve may be switched so that the cooling water flows to the radiator. By doing this, even when the bypass valve is stuck firmly, when the stuck tightness is detected,
Cooling water can be flowed from the internal combustion engine to the vicinity of the water temperature sensor in the cooling water circulation circuit, and the cooling water temperature corresponding to the actual temperature of the internal combustion engine can be detected by the water temperature sensor, ensuring the cooling water temperature detection accuracy. can do.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. First, the configuration of the entire cooling system will be described with reference to FIG. At the inlet of the cooling water passage (water jacket) of the engine 11 which is an internal combustion engine, the engine 1
Mechanical water pump 12 driven by power of 1
Is provided. The outlet of the cooling water passage of the engine 11 and the inlet of the radiator 13 are connected by a cooling water circulation pipe 14, and the outlet of the radiator 13 and the suction port of the mechanical water pump 12 are connected by a cooling water circulation pipe 15. As a result, a cooling water circulation circuit 16 in which the cooling water circulates through the cooling water passage of the engine 11 → the cooling water circulation pipe 14 → the radiator 13 → the cooling water circulation pipe 15 → the mechanical water pump 12 → the cooling water passage of the engine 11 is configured. ing.

The cooling water circulation circuit 16 is provided with a bypass passage 17 in parallel with the radiator 13, and both ends of the bypass passage 17 are connected in the middle of the cooling water circulation pipes 14 and 15. A flow rate control valve 18 (corresponding to a control valve) is provided at the confluence of the bypass passage 17 and the cooling water circulation pipe 15. The flow rate control valve 18 is composed of an electromagnetic valve capable of controlling the flow rate ratio of the cooling water flowing through the radiator 13 and the bypass flow passage 17, respectively. Further, a bypass valve 19 is provided in the middle of the bypass passage 17. This bypass valve 19 is composed of, for example, a normally open electromagnetic valve, and by simply switching between open and closed valves,
It has no function to control the valve opening (bypass flow rate).

A hot water circuit 20 for heating and a hot water circuit 21 for heat storage are provided in parallel with the engine 11. An electromagnetic valve 22 is provided in the hot water circuit 20 for heating.
And a heater core 23 for heating are connected in series, and in the hot water circuit 21 for heat storage, a regenerator 24 having a heat retaining structure formed of a heat retaining material (insulating material) and an electric water pump 25 are connected in series. Has been done.

When the passenger compartment is to be heated while the engine 11 is operating, the electromagnetic valve 22 is opened to allow a part of the warm water (cooling water) flowing out of the engine 11 to flow to the heater core 23.
The heat released from the heater core 23 heats the blown air from the air conditioner (not shown). Further, when the ignition switch (hereinafter referred to as “IG switch”) is turned off to stop the engine 11, the electric water pump 25 is activated to store hot water in the engine 11 in the heat storage unit 24.
It is collected inside and stored in a warm state.

On the other hand, a water temperature sensor 26 for detecting the cooling water temperature
Is installed on the cooling water outlet side of the engine 11 in the cooling water circulation circuit 16 and at a position where hot water from the heat storage device 24 does not circulate. The output signal of the water temperature sensor 26 is input to the control circuit 27 (ECU). This control circuit 27
Is mainly composed of a microcomputer, and executes the cooling system control routines of FIGS. 2 to 4 stored in the ROM (storage medium) of the microcomputer, so that each valve of the cooling system (flow control valve 18, bypass valve 19). ) And the start / stop of the electric water pump 25 in the hot water circuit 21 for heat storage.

Here, the outline of the control of the cooling system by the cooling system control routine of FIGS. 2 to 4 will be described based on the time chart of FIG. When the driver operates the IG switch from the OFF position to the ON position, the bypass valve 19 is closed and the bypass flow path 17 is shut off (bypass flow rate =
0%), the flow control valve 18 is maintained in a state in which the flow path of the radiator 13 is blocked (radiator flow rate = 0%), and the electric water pump 25 is activated.
The warm water stored in the heat storage unit 24 is preheated in the engine 11 by flowing in the engine 11 in a direction opposite to the circulation direction of the cooling water in the engine 11 after starting, as indicated by a dashed arrow in FIG.

After that, when the driver operates the IG switch from the ON position to the start position to start the starter (not shown) and starts the engine 11, the engine rotation speed N
When e has risen above a predetermined start completion rotation speed (for example, 400 rpm), it is determined that the engine 11 has been started, the electric water pump 25 is turned off, and the hot water supply to the engine 11 is terminated. .

As shown in FIG. 5, when the time from the start of supplying hot water to the engine 11 to the completion of starting the engine 11 exceeds a predetermined time (for example, 7 seconds), the engine 11 is still started. Even if is not completed, it is determined that the cooling water passage of the engine 11 is filled with hot water, the electric water pump 25 is turned off, and the hot water supply to the engine 11 is terminated.

Then, the electric water pump 25 is OF
At the time point F (when the hot water supply to the engine 11 is completed), the bypass valve 19 is opened to bypass the bypass passage 1
Open 7. After that, the cooling water is circulated from the engine 11 only to the bypass passage 17 until the warming up of the engine 11 is completed, and after the warming up is completed, the cooling water temperature detected by the water temperature sensor 26 is changed according to the engine operating state. The control amount of the flow rate control valve 18 is feedback-controlled so as to match the set target water temperature, and the cooling water flow rate to the bypass flow path 17 (bypass flow rate) and the cooling water flow rate to the radiator 13 (radiator flow rate) are controlled. Control the flow rate ratio.

When heating the passenger compartment while the engine 11 is operating, the electromagnetic valve 22 in the hot water circuit 20 for heating is used.
Is opened and a part of the warm water (cooling water) flowing out from the engine 11 is made to flow to the heater core 23, and the heat radiation of the heater core 23 heats the blown air of the air conditioner (not shown).

After that, when the driver operates the IG switch from the ON position to the OFF position to stop the operation of the engine 11, immediately the electric water pump 25 in the hot water circuit 21 for heat storage is started, 1, hot water in the engine 11 flows in a direction opposite to the circulation direction of the cooling water during engine operation, and the hot water is collected in the heat storage unit 24. As a result, hot water is stored in the heat storage unit 24 in a heat retaining state until the next engine start.

After that, when a predetermined time (for example, 7 seconds) from the start of collecting hot water in the heat storage unit 24 to the time when sufficient hot water is stored in the heat storage unit 24 has passed, the electric water pump 25 To stop collecting hot water in the heat storage unit 24.

FIG. 2 for executing the control of the cooling system described above
Through the cooling system control routine of FIG. 4, the IG switch is turned on.
Afterwards, it is activated every predetermined time (for example, every 16 msec), and plays a role as a cooling water circulation control means in the claims. When this routine is started, first, step 101
Then, it is determined whether or not the IG switch has just been operated from the OFF position to the ON position, and if it is immediately after being operated to the ON position, the process proceeds to step 102, where the current cooling water temperature detected by the water temperature sensor 26 is detected. THW is set as the cooling water temperature THWint (initial value of the cooling water temperature) before hot water supply, and in the next step 103, the drive flag XEWP of the electric water pump 25 is set to ON (drive) to set the electric water pump 25. Is started and the hot water stored in the heat storage unit 24 is supplied into the engine 11 to preheat the engine 11.

Further, in the next step 104, the drive flag XBIP of the normally open type bypass valve 19 is turned on (closed).
Is set to 0, the bypass valve 19 is closed, the bypass flow path 17 is shut off, and in the following step 105, the control amount TQ of the flow control valve 18 is set to 0%, and the flow control valve 18 is set to the flow of the radiator 13. Keep the road blocked. As a result, before starting the engine 11
The hot water supplied to the cooling water circulation circuit 16 is prevented from flowing into the cooling water circulation circuit 16.

The processing of steps 102 to 105 described above is an initialization processing which is executed only once immediately after the IG switch is operated from the OFF position to the ON position, and this routine is started at other times. Sometimes, these initialization processes (steps 102 to 105) are skipped and the process proceeds to step 106.

In step 106, it is determined whether the IG switch is ON or OFF. If the IG switch is ON, the process proceeds to step 107, where the ON time counter CIGON for counting the elapsed time after the IG switch is turned ON is incremented, In the next step 108, an OFF time counter CIGO that counts the elapsed time after the IG switch is turned off
Reset FF to 0. On the contrary, the IG switch is OF
If it is F, the process proceeds to step 109, the ON time counter CIGON is reset to 0, and the next step 110
Then, the OFF time counter CIGOFF is incremented.

After that, the process proceeds to step 111 of FIG.
By determining whether or not the count value of the N-hour counter CIGON has reached a predetermined time (for example, 7 seconds) or more, it is determined whether or not a predetermined time (for example, 7 seconds) has elapsed from the start of hot water supply, and the predetermined time If so, step 1
13, the drive flag X of the electric water pump 25
The EWP is set to OFF (stop), the electric water pump 25 is stopped to end the hot water supply to the engine 11, and the drive flag XBIP of the normally open type bypass valve 19 is set to OFF (open). Then, the bypass valve 19 is opened and the bypass flow path 17 is opened.

On the other hand, when the count value of the ON time counter CIGON has not reached the predetermined time (for example, 7 seconds), the routine proceeds from step 111 to step 112, where the engine rotation speed Ne is the predetermined start completion rotation speed (for example, 40 seconds).
0 rpm) or more, it is determined whether or not the engine 11 has been started. If it is determined that the engine 11 has been started, the process proceeds to step 113, and the electric water pump 25 is stopped. Then, the hot water supply to the engine 11 is terminated, and the bypass valve 19 is opened to open the bypass flow passage 17.

When it is determined to be "No" in both steps 111 and 112, if the hot water is being supplied to the engine 11, the hot water supply is continued as it is, and if it is immediately after the IG switch is turned off, the operation described later. Step 4 of 4
By the subsequent processing, the warm water in the engine 11 is stored
Collect in.

When the hot water supply to the engine 11 has been completed by the processing of step 113, the routine proceeds to step 114, where it is determined whether or not the cooling water temperature THW detected by the water temperature sensor 26 has risen above a predetermined temperature (for example, 80 ° C.). Then, it is determined whether or not the warm-up of the engine 11 is completed, and if it is determined that the warm-up is not completed, the routine proceeds to step 117, where the control amount TQ of the flow control valve 18 is set to 0%, and the flow control is performed. The valve 18 is maintained in a state of blocking the flow path of the radiator 13. As a result, before the completion of warming up, the cooling water flowing out from the engine 11 does not flow through the radiator 13 and the bypass passage 1
Circulation through 7 prevents the radiator 13 from lowering the temperature of the cooling water.

On the other hand, if it is determined in the above step 114 that the warm-up is completed (cooling water temperature THW ≧ predetermined temperature), the routine proceeds to step 115, where the current engine operating state (for example, engine rotation speed Ne, intake air amount GN). ), The target water temperature THWTG is calculated by a map or a mathematical formula. Thereafter, the routine proceeds to step 116, where the control amount TQ of the flow rate control valve 18 is feedback-controlled so that the cooling water temperature THW detected by the water temperature sensor 26 matches the target water temperature THWTG. As a result, after warm-up, if the cooling water temperature THW detected by the water temperature sensor 26 is higher than the target water temperature THWTG, the cooling water flow rate to the radiator 13 (radiator flow rate).
To decrease the cooling water flow rate to the bypass passage 17 (bypass flow rate), and conversely, if the cooling water temperature THW detected by the water temperature sensor 26 is lower than the target water temperature THWTG, the cooling water flow rate to the radiator 13 ( Radiator flow rate)
Is controlled to increase the cooling water flow rate (bypass flow rate) to the bypass flow path 17 by feedback control of the control amount TQ of the flow rate control valve 18.

After that, the process proceeds to step 118 of FIG.
It is determined whether or not it is immediately after the G switch is operated from the ON position to the OFF position (immediately after the engine is stopped). If it is immediately after the G switch is operated to the OFF position, the process proceeds to step 119.
Turns on the drive flag XEWP of the electric water pump 25
(Drive) to start the electric water pump 25. As a result, immediately after the engine is stopped
The hot water inside is collected in the heat storage unit 24.

After that, the routine proceeds to step 120, where it is determined whether or not the count value of the OFF time counter CIGOFF has become a predetermined time (for example, 7 seconds) or more, so that it is a predetermined time (for example, 7 seconds) or more from the start of hot water recovery. It is determined whether or not the time has passed, and if the predetermined time or more has passed, step 12
1, the drive flag XE of the electric water pump 25
WP is set to OFF (stop), the electric water pump 25 is stopped, and hot water recovery to the heat storage unit 24 is completed.

Further, the control circuit 27 executes the bypass valve open / sticking determination routine of FIG. 6 stored in the ROM so that a predetermined time (for example, 3 to 7 seconds) has elapsed from the start of supplying hot water to the engine 11. Detection value T of the water temperature sensor 26
HW and detection value THW of the water temperature sensor 26 before the start of hot water supply
Based on the difference from int, it is determined whether or not there is open sticking that leaves the bypass valve 19 open.

If the bypass valve 19 is stuck open, when hot water is supplied from the heat storage unit 24 to the engine 11 before starting, the hot water flows from the engine 11 to the vicinity of the water temperature sensor 26 in the cooling water circulation circuit 16. Since it flows in, the cooling water temperature THW detected by the water temperature sensor 26 becomes higher than the actual temperature of the engine 11 due to the influence of the hot water. As a result, when the bypass valve 19 is stuck open, as shown in FIG. 7, the detection value TH of the water temperature sensor 26 increases as time elapses from the start of hot water supply.
W and the detection value THWi of the water temperature sensor 26 before the start of hot water supply
The difference from nt (normal cooling water temperature) becomes large. From this relationship, the difference (absolute value) between the detection value THW of the water temperature sensor 16 after a certain amount of time from the start of the hot water supply and the detection value THWint before the start of the hot water supply is a predetermined open sticking determination value. It is possible to determine whether or not the open valve of the bypass valve 19 is stuck.

In this embodiment, in order to increase the reliability of the open sticking determination, after a predetermined time has elapsed from the start of hot water supply,
Difference between detection value THW of water temperature sensor 16 and detection value THWint of water temperature sensor 26 before starting hot water supply | THW-TH
The process of determining whether Wint | is larger than a predetermined open-sticking determination value is repeated in a predetermined cycle, and as a result, | TH
When the state where W-THWint | is determined to be larger than the open sticking determination value continues for a predetermined number of times, it is determined that the bypass valve 19 is open stuck, and the bypass valve open sticking flag is set to "1". ing.

The bypass valve open / fixed determination routine of FIG. 6 for executing the open / closed determination of the bypass valve 19 described above is performed at predetermined intervals (for example, 16 times) after the IG switch is turned on.
It is activated every m seconds) and functions as an open sticking determination means in the claims. When this routine is started, first, at step 201, whether the open sticking determination execution condition is satisfied or not is incremented at step 107 of FIG. 2 and the count value of the ON time counter CIGON is, for example, 3 seconds to 7 seconds. Within the range up to and before starting. That is, if the elapsed time after the start of supplying hot water to the engine 11 is, for example, a period from 3 seconds to 7 seconds and before the start, the open sticking determination execution condition is satisfied, and in other cases, the open sticking is performed. The determination execution condition is not satisfied, and this routine is terminated without performing the subsequent processing.

On the other hand, if the open sticking determination execution condition is satisfied, the routine proceeds to step 202, where the difference | THW- between the current detected value THW of the water temperature sensor 16 and the detected value THWint of the water temperature sensor 26 before the start of hot water supply. It is determined whether THWint | is larger than a predetermined open sticking determination value, and | THW-
If THWint | is less than or equal to the open sticking determination value, it is determined that the open sticking of the bypass valve 19 has not occurred, the process proceeds to step 203, the open sticking counter is reset to “0”, and in the next step 204, The bypass valve open fixation flag is reset to "0" and this routine ends.

On the other hand, in step 202, | T
If it is determined that HW-THWint | is larger than the open sticking determination value, there is a possibility that open sticking of the bypass valve 19 has occurred, so the routine proceeds to step 205, where the open sticking counter is incremented, and Step 206
Then, it is determined whether or not the value of the open sticking counter exceeds a predetermined value. As a result, if the value of the open sticking counter is equal to or less than the predetermined value, the routine is finished without determining the open sticking.

If it is determined in step 206 that the value of the open sticking counter exceeds the predetermined value, it is finally determined that the sticking is open, and the process proceeds to step 207, in which the bypass valve open sticking flag is set to "1". “” To end this routine.

Further, the control circuit 27 executes the bypass valve closed / sticking determination routine stored in the ROM shown in FIG. 8 to detect the detected value THW of the water temperature sensor 26 after a predetermined time has elapsed from the start and before starting the hot water supply. Based on the difference from the detected value THWint of the water temperature sensor 26, it is determined whether or not there is a closed sticking condition in which the bypass valve 19 is left closed.

If the bypass valve 19 is stuck closed, as shown in FIG. 9, the bypass flow by the bypass valve 19 and the flow rate control valve 18 is the same as that during the hot water supply to the engine 11 before the start as shown in FIG. Since the flow of the cooling water to the passage 17 and the radiator 13 is maintained in a blocked state, the cooling water of the engine 11 circulates in the cooling water even if the engine 11 is warmed up after a certain time has passed from the start. There is no flow around the water temperature sensor 26 in the circuit 16, and the detection value THW of the water temperature sensor 26 does not change much from the detection value THWint of the water temperature sensor 26 before the start of hot water supply. Therefore, when the bypass valve 19 is stuck closed, as shown in FIG. 9, the detected value THW of the water temperature sensor 26 does not rise to the water temperature corresponding to the completion of warming up, even if the engine 11 has actually warmed up. It is erroneously determined that the flow control valve 18 has not been warmed up.
As a result, the flow of the cooling water to the radiator 13 is maintained in a blocked state, and the state in which the increase in the cooling water temperature THW detected by the water temperature sensor 26 is small continues. From this relationship, the detected value THW of the water temperature sensor 26 after a lapse of a predetermined time from the start and the detected value T of the water temperature sensor 26 before the start of hot water supply
Whether or not the bypass valve 19 is stuck closed can be determined based on whether or not the difference from HWint is smaller than a predetermined closed sticking determination value.

When it is determined that the bypass valve 19 is closed and stuck, the flow control valve 18 is forcibly switched so that all the cooling water from the engine 11 flows to the radiator 13. By doing so, even when the bypass valve 13 is stuck and closed, the cooling water can be caused to flow from the engine 11 to the vicinity of the water temperature sensor 26 in the cooling water circulation circuit 16 when the close and sticking is detected. Thus, the water temperature sensor 26 can detect the cooling water temperature corresponding to the actual temperature of the engine 11.

In this embodiment, in order to improve the reliability of the closed sticking determination, a predetermined time (for example, 10 to 30) from the start.
Seconds), a process of determining whether the difference | THW-THWint | between the detection value THW of the water temperature sensor 16 and the detection value THWint of the water temperature sensor 26 before the start of hot water supply is smaller than a predetermined closed fixation determination value. Is repeated at a predetermined cycle, and as a result, | THW-THWint | is determined to be smaller than the closed sticking determination value for a predetermined number of times consecutively,
When it is determined that the bypass valve 19 is stuck closed, the bypass valve closed sticking flag is set to "1".

The bypass valve open / fixed determination routine of FIG. 8 for executing the closed / closed determination of the bypass valve 19 described above is performed every predetermined time (for example, 16 times) after the IG switch is turned on.
It is activated every m seconds) and functions as the closed sticking determination means in the claims. When this routine is started, first, at step 301, it is determined whether or not the engine has been started after the engine speed Ne has risen above a predetermined start completion speed (for example, 400 rpm) and whether or not the starter has been turned off. If it is determined that it has not been started yet, the routine proceeds to step 302, where a post-start counter that counts the elapsed time after the start is reset to "0". on the other hand,
If it is determined that the engine has been started, the routine proceeds to step 303, where the after-start counter is incremented.

After this, the routine proceeds to step 304, where the count value of the post-start counter (elapsed time after start) is, for example, 10
Whether or not it is the closed sticking determination period is determined depending on whether it is within the range from 2 seconds to 30 seconds. If it is not the closed sticking determination period, the present routine is terminated without performing the subsequent processing.

On the other hand, if it is the closed sticking determination period, the routine proceeds to step 305, where the current detected value T of the water temperature sensor 16 is reached.
HW and detection value THW of the water temperature sensor 26 before the start of hot water supply
It is determined whether the difference | THW-THWint | from the int is smaller than a predetermined closed sticking determination value, and | THW-THW
If int | is greater than or equal to the closed sticking determination value, it is determined that the closed sticking of the bypass valve 19 has not occurred, and step 3
In step 06, the closed sticking counter is reset to "0", and in the next step 307, the bypass valve closed sticking flag is reset to "0", and this routine ends.

On the other hand, in step 305, | T
If it is determined that HW-THWint | is smaller than the closed sticking determination value, there is a possibility that closed sticking of the bypass valve 19 has occurred, so the routine proceeds to step 308, where the closed sticking counter is incremented, and Step 309
Then, it is determined whether or not the value of the closed sticking counter exceeds a predetermined value. As a result, if the value of the closed sticking counter is equal to or smaller than the predetermined value, the routine is finished without determining the closed sticking.

If it is determined in step 309 that the value of the closed sticking counter exceeds the predetermined value, it is finally determined that the sticking is closed, and the process proceeds to step 310 to set the bypass valve closed sticking flag to "1". ", And the control amount TQ of the flow rate control valve 18 is set to 100%, and the flow rate control valve 18 is switched so that all the cooling water from the engine 11 flows to the radiator 13.

Further, the control circuit 27 executes the fuel injection control routine of FIG. 10 stored in the ROM to correct the fuel injection amount according to the cooling water temperature detected by the water temperature sensor 26 or the estimated water temperature, and finally. Calculate the injection amount.

By the way, when the bypass valve 19 is in the open and fixed state, as shown in FIG. 11, the detection value THW of the water temperature sensor 26 at the time of starting is affected by the hot water supplied from the heat storage unit 24. Since the temperature is higher than the actual temperature of the engine 11, it is better to estimate the cooling water temperature based on the detection value THWint of the water temperature sensor 26 before the start of the hot water supply and the elapsed time after the start of the detection value T of the water temperature sensor 26.
A temperature closer to the actual temperature of the engine 11 than HW can be obtained. Therefore, when the bypass valve 19 is stuck open, if the fuel injection amount is corrected based on this estimated cooling water temperature, compared to the case where the fuel injection amount is corrected based on the detection value THW of the water temperature sensor 26. The fuel injection amount can be accurately corrected.

Even if the bypass valve 19 is stuck open, the detected value TH of the water temperature sensor 26 increases as the temperature of the engine 11 increases with the lapse of time after the start.
Since W approaches the actual temperature of the engine 11, the fuel injection amount is corrected using the detected value THW of the water temperature sensor 26 instead of the estimated cooling water temperature after the temperature difference between the two has decreased to some extent. With this configuration, when the bypass valve 19 is stuck open, the fuel injection amount can be corrected by using the reliable one of the estimated cooling water temperature and the detected value THW of the water temperature sensor 26. It is possible to avoid deterioration of air-fuel ratio controllability.

FIG. 1 for executing the fuel injection control described above
The fuel injection control routine of 0 is activated every predetermined time (for example, every 16 msec) after the IG switch is turned on, and functions as a fuel injection control means in the claims.
When this routine is started, first, at step 401, it is judged if the count value of the post-start counter (elapsed time after start) incremented at step 301 of FIG. 8 is less than or equal to the predetermined time K1. Here, the predetermined time K
1 is for setting a period in which it is assumed that the cooling water temperature on the cooling water outlet side of the engine 11 (hereinafter referred to as "engine outlet cooling water temperature") ETHW is equal to the detected value THWint of the water temperature sensor 26 before the start of hot water supply. is there. Therefore,
If the count value of the after-start counter is less than or equal to the predetermined time K1, the detection value THWint of the water temperature sensor 26 before the start of hot water supply is used as the engine outlet cooling water temperature ETHW.

On the other hand, if the count value of the counter after starting exceeds the predetermined time K1, the routine proceeds to step 403, where it is determined whether or not the bypass valve open / sticking flag is "1" and the bypass valve 19 is open / fixed. When the open sticking has not occurred (when the bypass valve open sticking flag = 0), the engine outlet cooling water temperature ETHW and the detection value THW of the water temperature sensor 26 substantially match. Therefore, the process proceeds to step 406, and the detected value THW of the water temperature sensor 26 is used as it is as the engine outlet cooling water temperature ETHW.

On the other hand, when the bypass valve 19 is stuck open (bypass valve open flag = 1), the engine outlet cooling water temperature ETHW and the water temperature sensor 2 are detected.
Since the detected value THW of 6 does not match, step 404
Then, the engine outlet cooling water temperature ETHW is estimated by the following equation. ETHW (i) = ETHW (i-1) + C

Here, ETHW (i) is the current engine outlet cooling water temperature estimated value, ETHW (i-1) is the previous engine outlet cooling water temperature estimated value, and C is the water temperature increase amount per calculation cycle. The water temperature increase amount C per calculation cycle may be a fixed value in order to simplify the calculation process, but the engine operating state, the outside air temperature, the previous engine outlet cooling water temperature ETHW (i
-1) or the like, the water temperature increase amount C per calculation cycle may be calculated by a map or a mathematical formula. In the above equation, the initial value of the engine outlet cooling water temperature ETHW becomes the detection value THWint stored in step 402 before the hot water supply starts, and therefore the engine outlet cooling water temperature ETHW is estimated by the above equation. It is performed based on the previous detection value THWint of the water temperature sensor 26, the elapsed time after start (the number of calculations after start), and the like.

After estimating the engine outlet cooling water temperature ETHW,
Whether the count value of the post-start counter (elapsed time after start) has become equal to or greater than the predetermined time K2 in step 405,
Alternatively, the difference between the estimated engine outlet cooling water temperature ETHW and the current detected value THW of the water temperature sensor 26 | ETHW-T
It is determined whether HW | has become equal to or less than a predetermined value. Here, in the predetermined time K2, the difference between the engine outlet cooling water temperature ETHW and the detection value THW of the water temperature sensor 26 becomes small (becomes less than or equal to the predetermined value) when the bypass valve 19 is stuck open.
It is the elapsed time after startup required up to and is set by being measured in advance by experiments or the like. The predetermined time K2 may be a fixed value in order to simplify the calculation process, but the predetermined time K2 may be a map or a mathematical expression according to the engine operating state, the outside temperature, and the like.
2 may be calculated.

In step 405, if the count value of the counter after starting exceeds the predetermined time K2, or
Difference between estimated engine outlet cooling water temperature ETHW and current detection value THW of water temperature sensor 26 | ETHW-THW |
If either of the values falls below a predetermined value, the estimation of the engine outlet cooling water temperature ETHW is ended, the process proceeds to step 406, and the detected value THW of the water temperature sensor 26 is used as the engine outlet cooling water temperature ETHW (that is, the engine outlet cooling water temperature ETHW). The outlet cooling water temperature ETHW is detected by the water temperature sensor 26).
On the other hand, in step 405, if neither of the above conditions is met, the engine outlet cooling water temperature ETHW estimated in step 404 is used as it is.

As described above, the engine outlet cooling water temperature E
After THW is determined to be either the estimated value or the detected value, the routine proceeds to step 407, where correction factors ephase1, e for the fuel injection amount are based on the engine outlet cooling water temperature ETHW.
face2 and FWL are calculated by a map or a mathematical formula.

After that, the routine proceeds to step 408, where the fuel injection amount TAU is calculated by the following equation. TAU = basic injection amount × α × (1 + FWL + ephase1
+ Efase2) Here, the basic injection amount is a basic fuel injection amount calculated by a map or the like according to the engine operating state (for example, engine rotation speed, intake air amount, etc.). α is various correction coefficients such as an air-fuel ratio feedback correction coefficient, a learning correction coefficient, and an acceleration / deceleration correction coefficient.

In step 407, three kinds of correction coefficients efas are set according to the engine outlet cooling water temperature ETHW.
e1, efase2, and FWL are calculated,
These three types of correction coefficients may be integrated into one correction coefficient for calculation.

According to the cooling system control routine of FIGS. 2 to 4 described above, when the hot water in the heat storage unit 24 is supplied to the engine 11 before starting, the radiator 13 and the bypass flow are controlled by the flow rate control valve 18 and the bypass valve 19. The flow of cooling water to the passage 17 is cut off.

In the present embodiment described above, the bypass valve 19 is provided in the bypass passage 17, and when the hot water in the heat storage unit 24 is supplied to the engine 11 before starting, the bypass valve 19 is closed to bypass. Since the flow passage 17 is cut off and the flow passage of the radiator 13 is cut off by the flow control valve 18, the hot water supplied to the engine 11 from the heat storage device 24 before starting is prevented from flowing into the cooling water circulation circuit 16. As a result, it is possible to prevent the preheating effect of the inner engine 11 from being reduced by the hot water, and to improve the early warm-up performance at the time of starting.

Moreover, when the hot water in the heat storage unit 24 is supplied to the engine 11 before starting, it is possible to prevent the hot water from flowing around the water temperature sensor 26 in the cooling water circulation circuit 16, so that the water temperature sensor before starting. It is possible to prevent the detected water temperature of 26 from rising and prevent the water temperature sensor 26 from detecting a temperature of hot water that is higher than the actual temperature of the engine 11 at the time of starting. The reliability can be improved. As a result, even if the fuel injection amount is corrected based on the cooling water temperature detected by the water temperature sensor 26 at the time of starting, it is possible to prevent the air-fuel ratio from becoming leaner than the target air-fuel ratio at the time of starting, and to set the target air-fuel ratio. It can be stabilized near the air-fuel ratio, and engine speed fluctuations can be reduced.

In the conventional cooling system, the heat accumulator 2 is set before starting.
The hot water supplied to the engine 11 from the cooling water circulation circuit 1
6, and the hot water flows around the water temperature sensor 26 installed in the cooling water circulation circuit 16, as shown in FIG. 12, the water temperature detected by the water temperature sensor 26 rises from before the start, and the actual engine 11 The temperature of hot water that is higher than the temperature is detected, and the actual temperature of the engine 11 is still low, but it is erroneously detected that the temperature of the engine 11 is high. Therefore, if the fuel injection amount is corrected based on the detection value of the water temperature sensor 26 at the time of starting, the injection correction will be performed based on a temperature higher than the actual temperature of the engine 11, and as a result, it will be shown in FIG. As described above, the fuel injection amount at the time of starting becomes smaller than the appropriate value, the air-fuel ratio at the time of starting deviates to the lean side from the target air-fuel ratio, and the air-fuel ratio becomes unstable, resulting in large engine speed fluctuations. I got angry.

On the other hand, in the present embodiment, the detected value of the water temperature sensor 26 after a certain amount of time has elapsed from the start of the supply of hot water from the heat storage unit 24 to the engine 11 and the water temperature sensor 26 before the start of hot water supply. The presence or absence of open fixation of the bypass valve 19 is determined based on whether or not the difference from the detected value is larger than a predetermined open fixation determination value.
An appropriate fail-safe process can be performed when the open fixation of 9 occurs.

In this embodiment, when the bypass valve 19 is stuck open, the actual temperature of the engine 11 is affected by the detected value of the water temperature sensor 26 at the time of starting, which is affected by the hot water supplied from the heat accumulator 24 before starting. When it is determined that the bypass valve 19 is stuck open in consideration of the fact that the temperature is higher than the above temperature, the detected value of the water temperature sensor 26 before the start of the hot water supply is started until a predetermined period elapses from the start. Since the cooling water temperature is estimated based on the elapsed time after startup and the fuel injection amount is corrected based on the estimated cooling water temperature, the fuel is detected based on the detection value of the water temperature sensor 26 when the bypass valve 19 is stuck open. Compared with the case where the injection amount is corrected, the fuel injection amount can be corrected more accurately, and the air-fuel ratio can be prevented from shifting to the lean side.

Further, in the present embodiment, whether the difference between the detected value of the water temperature sensor 26 after a lapse of a predetermined period from the start and the detected value of the water temperature sensor 26 before the start of hot water supply is smaller than a predetermined closed sticking determination value. Therefore, the presence or absence of the closed sticking of the bypass valve 19 is determined. Therefore, when the closed sticking of the bypass valve 19 occurs, an appropriate fail-safe process can be performed.

In this case, when it is determined that the bypass valve 19 is closed and stuck, the flow control valve 18 is forcibly switched to flow the cooling water to the radiator 13, so that the bypass valve 19 is closed. Even when the engine 11 is stuck, the engine 11
The cooling water can be caused to flow around the water temperature sensor 26 in the cooling water circulation circuit 16, and the cooling water temperature corresponding to the actual temperature of the engine 11 can be detected by the water temperature sensor 26. Can be secured.

The bypass valve 19 determines whether the difference between the detected value of the water temperature sensor 26 after a lapse of a predetermined period from the start and the detected value of the water temperature sensor 26 at the beginning of the start is smaller than a predetermined closed sticking determination value. It may be possible to determine the presence or absence of closed sticking.

The flow control valve 18 used in the present embodiment is composed of an electromagnetic valve capable of controlling the flow rate ratio of the cooling water flowing through the radiator 13 and the bypass flow passage 17, respectively. A three-way switching valve that switches the flow of cooling water to and from the bypass passage 17 may be used.

Alternatively, instead of providing the bypass valve 19, an electromagnetic valve is provided upstream or downstream of the water temperature sensor 26 in the cooling water circulation pipe 14 to supply the hot water in the heat storage unit 24 to the engine 11 before starting. At this time, the flow of the cooling water to the radiator 13 and the bypass passage 17 may be blocked by closing this electromagnetic valve. In this case, it is not necessary to provide the bypass valve 19 in the bypass passage 17.

Further, the bypass valve 19 used in the present embodiment is only required to be able to simply switch between the open valve and the closed valve, and the function of controlling the opening degree (bypass flow rate) of the bypass valve 19 is not required. When the bypass valve 19 is composed of an electromagnetic valve whose opening degree can be controlled, an electromagnetic valve whose opening degree can be controlled is provided on the inlet side or the outlet side of the radiator 13 instead of the flow rate control valve 18, and these two opening degrees are controlled. By controlling the opening of the controllable electromagnetic valve, the same flow rate control as the flow rate control valve 18 of the present embodiment may be performed.

Further, in this embodiment, when the driver operates the IG switch from the OFF position to the ON position, the bypass valve 19 is closed and the electric water pump 25
Was started to start the supply of hot water from the heat storage device 24 to the engine 11. For example, when the door of the driver's seat is opened from the outside of the vehicle during parking (the door switch is turned on).
At the time), the bypass valve 19 may be closed to start the electric water pump 25 to start supplying hot water from the heat storage device 24 to the engine 11. In short, the engine 11 is started. The hot water supply to the engine 11 may be started at some point when it is detected that there is a high possibility that it will occur.

Further, in this embodiment, the flow control valve 1
8 is used, a thermostat valve may be used instead of the flow control valve 18. In addition, it goes without saying that the present invention may be implemented by omitting some of the various functions described above.

[Brief description of drawings]

FIG. 1 is a block diagram schematically showing a configuration of a cooling system according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a processing flow of a cooling system control routine (part 1).

FIG. 3 is a flowchart (part 2) showing a processing flow of a cooling system control routine.

FIG. 4 is a flowchart showing a processing flow of a cooling system control routine (part 3).

FIG. 5 is a time chart showing an example of control by a cooling system control routine.

FIG. 6 is a flowchart showing a processing flow of a bypass valve open / sticking determination routine.

FIG. 7 is a time chart showing an example of control when an open sticking of a bypass valve occurs.

FIG. 8 is a flowchart showing a processing flow of a bypass valve closed / sticking determination routine.

FIG. 9 is a time chart showing an example of control when the bypass valve is stuck closed.

FIG. 10 is a flowchart showing a flow of processing of a fuel injection control routine.

FIG. 11 is a time chart showing an example of control by a fuel injection control routine.

FIG. 12 is a time chart for explaining the effect of the present embodiment in comparison with the related art.

[Explanation of symbols]

11 ... Engine (internal combustion engine), 12 ... Mechanical water pump, 13 ... Radiator, 16 ... Cooling water circulation circuit, 17
... bypass passage, 18 ... flow rate control valve (control valve), 19 ... bypass valve, 23 ... heater core, 24
... heat storage device, 25 ... electric water pump, 26 ... control circuit (cooling water circulation control means, fuel injection control means, open sticking determination means, closed sticking determination means).

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F02N 17/06 F02N 17/06 D 17/08 17/08 E (72) Inventor Shigeru Kamio Kariya city, Aichi prefecture 1-chome, Showa-cho, DENSO Co., Ltd. (72) Inventor, Eizo Takahashi 1-1-chome, Showa-cho, Kariya City, Aichi Prefecture Automobile Co., Ltd. (72) Inventor Shigetaka Yoshikawa 1 Toyota-cho, Toyota-shi, Aichi F-Term (To be referred to) Toyota Automobile Co., Ltd. (reference) 3G084 BA09 BA13 BA28 CA01 CA02 DA04 DA09 DA12 EA07 FA07 FA20 FA33 FA36 3G301 HA01 JA08 JA20 KA01 LB01 MA11 PA01Z PE01Z PE08Z

Claims (8)

[Claims] 1. A cooling water circulation circuit for circulating cooling water between an internal combustion engine and a radiator, a bypass flow passage provided in the cooling water circulation circuit so as to bypass the radiator, and a cooling passage heated by the internal combustion engine. Cooling water (hereinafter "warm water"
Is stored in a heat retaining state and supplies it to the internal combustion engine before the next start, and a valve provided in the cooling water circulation circuit and / or the bypass flow path is controlled to store the heat before starting. In a cooling system control device for an internal combustion engine, comprising: a cooling water circulation control means for switching the valve to a state in which the flow of the cooling water from the internal combustion engine to the bypass flow passage is cut off when hot water is supplied from the reactor to the internal combustion engine, A cooling system for an internal combustion engine, wherein a water temperature sensor for detecting the temperature of cooling water is installed at a cooling water outlet side of the internal combustion engine in the cooling water circulation circuit and at a position where hot water from the heat accumulator does not circulate. Control device. 2. The cooling water circulation control means opens the bypass flow passage at the time of start-up and causes the cooling water flowing out of the internal combustion engine to flow through the bypass flow passage to be circulated, and the cooling water temperature detected by the water temperature sensor at the time of start-up. 2. The cooling system control device for an internal combustion engine according to claim 1, further comprising fuel injection control means for correcting the fuel injection amount based on the above. 3. The bypass valve is based on a difference between a detection value of the water temperature sensor after a lapse of a predetermined period from the start of hot water supply from the heat storage device to the internal combustion engine and a detection value of the water temperature sensor before start of hot water supply. The cooling system control device for an internal combustion engine according to claim 1 or 2, further comprising open sticking determination means for determining whether there is open sticking that is left open. 4. The detection value of the water temperature sensor before the start of hot water supply and after the start until a predetermined period elapses from the start when the open sticking determination means determines that the bypass valve is stuck open. 4. The cooling system control device for an internal combustion engine according to claim 3, further comprising means for estimating the cooling water temperature based on the elapsed time and correcting the fuel injection amount based on the estimated cooling water temperature. 5. The cooling water temperature based on the detection value of the water temperature sensor before starting hot water supply after starting and the elapsed time after starting when the bypass sticking determining means determines that the bypass valve is stuck open. And a means for correcting the fuel injection amount based on the estimated cooling water temperature until the difference between the estimated cooling water temperature and the detected value of the water temperature sensor after starting becomes less than a predetermined value. The cooling system control device for an internal combustion engine according to claim 3. 6. A control valve having a function of switching the flow of cooling water in the cooling water circulation circuit between the radiator and the bypass passage or a function of controlling a flow rate ratio between the radiator and the bypass passage, and a control valve provided in the bypass passage. And a bypass valve, wherein the cooling water circulation control means maintains the control valve in a state of blocking the flow of cooling water to the radiator when supplying hot water from the heat storage device to the internal combustion engine, and 6. The cooling system control device for an internal combustion engine according to claim 1, wherein a bypass valve is closed to shut off the bypass flow passage. 7. A closed sticking condition in which the bypass valve is left closed based on a difference between a detected value of the water temperature sensor after a lapse of a predetermined period from the start and a detected value of the water temperature sensor before or at the start of hot water supply. 7. The cooling system control device for an internal combustion engine according to claim 6, further comprising closed sticking determination means for determining presence / absence. 8. The cooling water circulation control means, when the closed sticking determination means determines that the bypass valve is stuck closed, switches the control valve to flow cooling water to the radiator. The cooling system control device for an internal combustion engine according to claim 7.