JPH0347422A - Cooling method for internal combustion engine - Google Patents

Abstract

PURPOSE:To perform cooling of an internal combustion engine in good performance according to the car running condition varying diversified by controlling the amount of the fluid to be heat exchanged, which circulates in the engine according to the requisite cooling capacity. CONSTITUTION:A water pump 115 is operated with driving of an engine 101, and the cooling water passes through the engine 101, No.1 water introduction path 103, and radiator 102 to flow again into the engine 101. When the temp. of cooling water sensed by a temp. sensor 113 is lower than No.1 specified temp., the revolving speed of the water pump 115 is controlled, and the amount of cooling water flowing into the engine 101 will decrease. When the temp. of cooling water is over No.1 specified value, the amount of cooling water will increase; and a flow adjusting valve 106 operates when the temp. of the cooling water is over No.2 specified value, or when the revolving speed of the engine 101 is over a certain value, to allow the cooling water flowing in the No.2 water introduction path 104 to flow into a bypass 105 with the engine 101 detoured.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a cooling method for cooling an internal combustion engine such as an automobile engine.

[Conventional technology]

Generally, in order to cool an automobile engine, as shown in FIG. 8, an engine 301 and a radiator 302 are connected by a fluid pipe 304, and cooling water flowing between the two is circulated by a water pump 303.

The inlet side and the outlet side of the radiator 302 are communicated with each other through a bypass pipe 305, and when the temperature of the cooling water flowing out from the automobile engine 301 is below a predetermined value, the cooling water is allowed to flow into the bypass pipe 305. radiator 30
Bypass 2.

On the other hand, when the coolant temperature is above a predetermined value, the bypass pipe 305 is closed by closing the thermostat 306, and the coolant is allowed to flow through the radiator to cool the coolant. Note that 308 in the figure is a heater core that heats the interior of the vehicle.

In such a cooling device, the automobile engine 30
1, it is necessary to control the cooling performance of the cooling device according to variously changing operating conditions. In other words, since the water pump has traditionally been controlled by engine drive, the cooling system is most difficult to operate under various operating conditions (for example, when climbing at low speeds), or the cavity that occurs when the water pump rotates at high speeds. The capacity of the water pump is determined from the limit value. Therefore, under various operating conditions, it is sufficient to circulate the optimum amount of cooling water for areas where the amount of circulation from the water pump is greater than necessary, or conversely, where more circulation is desired. There are problems that cannot be addressed.

In addition, as the output of the automobile engine 301 increases in recent years, the amount of cooling heat released from the engine 301 to the cooling water increases, and in order to dissipate the increased amount, the radiator 30
2. There is a need to increase the size of the cooling fan 307. However, the inside of the engine room tends to become smaller and smaller, making it extremely difficult to increase the size of the radiator 302 and cooling fan 307. Therefore, increasing the discharge capacity of the water pump 303 may be considered to cope with the increase in the amount of heat lost in cooling of the engine 301, but the amount of heat lost in cooling released from the engine 301 to the coolant will also be increased by the increased amount of coolant. This results in the problem that the radiator 302 and the cooling fan 307 must be made larger. In addition, when the amount of cooling water is increased, the temperature of the cooling water rises slowly when the automobile engine 301 is started, and the automobile engine 301
There is also the problem that the warm-up characteristics of the engine deteriorate.

Therefore, as disclosed in Japanese Patent Application Laid-Open No. 63-268912, a cooling water inlet for introducing cooling water into the engine (14) and a cooling water outlet for drawing out the cooling water from the engine (14) are connected. Some of them are provided with a bypass passage (17) for adjusting the flow rate of the bypass passage (17) and a flow rate ratio of the passage on the side where the bypass passage (17) and the cooling water outlet meet.

With the above configuration, the flow of cooling water is controlled by adjusting the regulating valve (15) without deteriorating the warm-up characteristics, and the temperature of the sliding surface of the cylinder liner is maintained within the optimum temperature range. The engine can be cooled well.

[Problem to be solved by the invention]

However, in the above publication, the water pump (13) for circulating the cooling water is driven by the engine (14), so the amount of cooling water circulating in the cooling system always depends on the rotation of the engine (14). and change.

Therefore, there is a problem in that the cooling water cannot be efficiently flowed according to the cooling performance when the amount of cooling water is required or when the amount of cooling water is not so necessary.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to effectively cool an internal combustion engine in accordance with variously changing driving conditions of a vehicle.

[Means to solve the problem]

In order to achieve the above object, the present invention includes a bypass passage through which the heat exchange fluid that has been heat exchanged by the heat exchanger flowing into the internal combustion engine flows through the second water conduit, bypassing the internal combustion engine. In a cooling device for an internal combustion engine in which a bypass passage is opened and closed by a flow rate control means, when a temperature corresponding to the heat capacity of the internal combustion engine is lower than a first predetermined temperature, the amount of heat exchange fluid flowing into the internal combustion engine is reduced, and the internal combustion engine is cooled. When the temperature according to the heat capacity of the engine is at least a first predetermined value, increasing the amount of heat exchange fluid flowing into the internal combustion engine, and when the temperature according to the heat capacity of the internal combustion engine is at least a second predetermined value, Alternatively, when the rotational speed of the internal combustion engine exceeds a predetermined value, the flow rate control means is operated to open the bypass passage, and the heat exchange fluid flowing through the second water conduit bypasses the internal combustion engine and flows into the bypass passage. Adopt means.

[Effect]

When the internal combustion engine is driven, the circulation means is operated, and the fluid to be heat exchanged passes through the internal combustion engine, the first conduit, the heat exchanger, and the second conduit and flows into the internal combustion engine again. When the temperature corresponding to the heat capacity of the internal combustion engine is lower than the first predetermined temperature, the amount of fluid to be heat exchanged flowing into the internal combustion engine decreases. Further, when the temperature according to the heat capacity of the internal combustion engine is equal to or higher than the first predetermined value, the amount of heat exchange fluid flowing into the internal combustion engine increases, and the temperature according to the heat capacity of the internal combustion engine becomes equal to or higher than the second predetermined value. or when the rotational speed of the internal combustion engine exceeds a predetermined value, the flow rate control means is activated, the bypass passage opens, and the heat exchange fluid flowing through the second water conduit bypasses the internal combustion engine and flows into the bypass passage. .

〔Effect of the invention〕

As described above, in the present invention, the amount of heat exchange fluid circulating within the internal combustion engine can be controlled according to the required cooling capacity. Therefore, the optimal heat exchange fluid necessary for cooling the internal combustion engine can be circulated, so that the internal combustion engine can be appropriately cooled in accordance with the variously changing operating conditions of the vehicle.

〔Example〕

FIG. 1 is a piping diagram of a cooling device showing an embodiment of the present invention. The automobile running engine 101 and the automobile radiator 102 are connected to a first water conduit 103 and a second water conduit 104.
are connected by.

That is, one end 103a of the first water conduit 103 is connected to the inlet side of the radiator 102, and the other end 103b is connected to the cylinder block side of the engine 101. One end 104a of the second water conduit 104 is connected to the outlet side of the radiator 102, and the other end 104b is connected to the cylinder head side of the engine 101. Cooling water that has reached a relatively high temperature due to the engine 101 flows into the radiator through the first conduit 103, where heat is exchanged and becomes low-temperature cooling water. This low-temperature cooling water flows into the engine 101 through the second conduit 104, flows from the cylinder head side to the cylinder block side, and cools the engine.

A water pump 115 (cooling water circulation means) that circulates cooling water between the engine 101 and the radiator 102 is disposed in the middle of the second water conduit 104 . This water pump 115 is rotationally driven by a hydraulic motor (not shown) or the like. The water pump 115 can be rotated independently of the engine speed by controlling the amount of oil flowing into the water pump 115. One end of a bypass passage 105 is connected to a position downstream of the water pump 115 of the second water conduit 104, and the other end of this bypass passage 105 is connected to the first water conduit 103.
It is connected to the. A flow rate adjustment valve 106 serving as a recirculation flow rate adjustment means is disposed in the middle of this bypass path 105. This flow rate adjustment valve 106 controls the valve opening using a hydraulic, electric, or negative pressure actuator.
A mechanical relief valve or the like is used.

One end of a radiator bypass passage 107 is connected to a position upstream of the water pump 115 of the second water conduit 104 . The other end of this radiator bypass passage 107 is connected to the first water conduit 103 so that the cooling water flowing through the first water conduit 103 can bypass the radiator 102 . Radiator bypass path 107 and second water conduit 1
A thermostat 108 is arranged at the connection part of 04, and when the temperature of the cooling water flowing into the radiator bypass passage 107 from the first water conduit 103 is below the set value, the radiator bypass passage 107 is opened and the set value is set. In the above case, the radiator bypass passage 107 is closed and the first water conduit 1
The entire amount of cooling water flowing through 03 flows into the radiator.

A radiator fan 112 for sucking cooling air into the radiator 102 is disposed on the rear surface of the radiator 102. This radiator fan 112 is rotationally driven by an electric motor 114 and a hydraulic motor (not shown).

One end of a heater flow path 109 is connected to the first water flow path 103, and the other end of this heater flow path 109 is connected to the second water flow path 103.
It is connected between the thermostat 108 of 04 and the water pump 115. A conventionally known heater core 110 is connected in the middle of the heater flow path 109, and a water valve 111 is disposed upstream thereof.

A water temperature sensor 113 is disposed within the first water conduit 103 to measure the temperature of the cooling water immediately after flowing out from the engine 101. Note that the engine wall temperature may be measured instead of the cooling water temperature.

Further, the cylinder head of the engine 101 is provided with a wall temperature sensor 120 that detects the head wall temperature.

Reference numeral 200 in FIG. 2 is an electronic control circuit (ECU), which includes an outside air temperature sensor 201 that senses the air temperature outside the vehicle interior, an intake air temperature sensor 202 that senses the air temperature taken into the engine 1. A negative pressure sensor 203 that senses the pressure inside the pipe, and a vehicle speed sensor 204 that senses the vehicle speed.
, a rotation speed sensor 205 that detects the engine 1010 rotation speed.
, receives a sensing signal from the wall temperature sensor 120. Upon receiving these signals, the optimal state of the cooling device is calculated, and control signals are sent to each of the flow rate adjustment valve 106, water valve 111, electric motor 114, and water pump 115.

Next, the operation of this embodiment will be explained.

When the engine 101 is driven, the hydraulic motor operates in response to the driving force, and the water pump 115 is rotated by the operation of the hydraulic motor. A portion of the cooling water discharged from the water pump 115 flows to the bypass passage 105 side, and the rest flows into the engine 101. The cooling water that cooled the engine 101 and became high temperature is transferred to the first water conduit 1
03 and flows into the radiator 102 through this first water conduit 103. Inside the radiator 102, heat is exchanged between the high-temperature cooling water and the outside air, and the cooled water is led out into the second water conduit 104, where it is returned to the water pump 1.
15 inhaled.

When the water temperature is below a predetermined value, such as immediately after starting the engine 101, the thermostat 108 opens and the cooling water flowing into the first water conduit 103 is transferred to the radiator bypass path 1.
By flowing through 07, the radiator 102 is bypassed.

When attempting to heat the interior of the vehicle, the water valve 111 is opened. Then, a portion of the high-temperature cooling water flowing out from the engine 101 into the first water conduit 103 flows through the heater flow path 109, exchanges heat with the introduced air within the heater core 110, and warms the introduced air. The heat-exchanged cooling water is again guided to the suction side of the water pump 115.

Here, the operation of water pump 115 will be explained in detail.

As shown in Fig. 3, the discharge flow rate of the water pump 115 is varied with respect to the engine rotation speed Ne (indicated by I in the figure).
, operation ■ (indicated by ■ in the figure), and operation ■ (indicated by ■ in the figure). In operation ■, engine speed Ne is N+
(approximately 800 rpm) or more, the discharge flow rate of the water pump 115 is kept constant at approximately 2 to 15 (1/win), and in operation
500 rpm) or more, water pump 1
15 discharge flow rate from 4 () to 60 (12/5in)
In operation ■, the engine speed Ne is N3.
(approximately 20 rpm) or more, the discharge flow rate of the water pump 115 is set to 100 to 150 (I!, 7 m1).
It is assumed to be constant at about n).

As described above, by changing the discharge -frLi of the water pump under certain conditions regardless of the engine speed, the required amount of cooling water can be circulated as needed. Therefore, the engine can be efficiently cooled.

Further, as shown in FIG. 4, the cooling water temperature Tw is at the first predetermined value Tw (60 to 80°
C), the discharge flow rate characteristic of the water pump 115 is set to operation I, and the cooling water temperature is 1%11 (60 to 80 degrees
C) or higher and the cooling water temperature Tw is lower than the second predetermined temperature THt (approximately 80 to 90°C), the discharge flow rate characteristic of the water pump 115 is activated (■), and the cooling water temperature Tw is set to Twt (approximately 90 to 90°C). (approximately 110°C) or higher, the discharge flow rate characteristic of the water pump 115 is activated. still,
In the figure, ■ indicates the discharge flow rate characteristic of the water pump 115 during idling, and when the cooling water temperature is Tw or higher, the discharge flow rate is always constant. Further, more detailed water pump control may be performed depending on the usage conditions of the vehicle.

Next, the processing executed by the ECU 200 will be explained based on the program flowchart shown in FIG. The program shown in FIG. 5 is executed from the time when starting of the engine 101 is completed.

First, in step 1001, the cooling water temperature is detected based on the signal from the water temperature sensor 113, and the cooling water temperature Tw is Tsyl.
If it is determined that it is lower, the process proceeds to step 1002.

In step 1002, water pump (W/P) 115
The discharge flow rate characteristic of the electric motor 1 is set to operation ■, and the
14 is turned off.

At this time, the cooling water is discharged by the water pump 115, and the cooling water is discharged from the other end side 104b of the second water conduit 104 to the engine 10.
1, the cylinder block of the engine 101, the other end side 103b of the first water conduit 103, and the bypass passage 107, and is sucked in by the water pump 115 from the one end side 104a of the first water conduit 104. That is, at this time, since the amount of cooling water is relatively low, the amount of circulating water is kept low to prevent overcooling of the engine 101, and
Good rise in cooling water temperature. Therefore, the engine is warmed up well. Note that at this time, the thermostat 108 is open, the cooling water bypasses the radiator 102 and flows through the radiator bypass path 107, and the electric motor 114 is not operating, so the radiator fan 11
2 does not rotate.

Then, the process advances to step 1003.

In step 1003, the flow rate adjustment valve 106 is closed, and then the process returns to step 1001 (in microsec units).

Further, in step 1001, the cooling water temperature Tw is Tw.

If it is determined that the above is the case, the process advances to step 1004.

In step 1004, if it is determined that the cooling water temperature Tw is lower than Twz based on the signal from the water temperature sensor 113,
Proceeding to step 1005, the discharge flow rate characteristic of the water pump 115 is set to operation (2). moreover,
The electric motor 114 operates, the radiator fan 112 rotates, and the cooling water flowing inside the radiator 102 is forcibly cooled. That is, as the temperature of the cooling water increases, the amount of circulating water is increased to suppress the temperature rise of the cooling water. This maintains the cooling water at an appropriate temperature (Tw, ~Twz) and cools the engine 101 well.

Note that since the thermostat 108 closes when the cooling water temperature Tw reaches about 80 to 90°C, the cooling water does not flow through the radiator bypass passage 107 but entirely flows through the radiator 102. Thereby, the cooling water is further cooled down.

Thereafter, the process advances to step 1003.

Further, in step 1004, the cooling water temperature Tw is Tw.

If it is determined that the above is the case, the process proceeds to step 1006, and in step 1006, the discharge flow rate characteristic of the water pump 115 is set to operation (2). At this time, as the cooling water temperature increases, the amount of circulating water is further increased to lower the cooling water temperature and maintain the cooling water temperature at an appropriate temperature (Tw+"Twz).

Thereafter, the process advances to step 1007.

In step 1007, the temperature of the engine head wall is detected based on the signal from the wall temperature sensor 120, and when it is determined that the temperature is equal to or higher than the engine head wall T□ (approximately 150 to 180°C), the process proceeds to step 1003.

In step 1003, the flow rate adjustment valve 106 is closed. Thereby, overheating of the wall temperature of the engine 101 can be prevented.

After that, the process returns to step 1001 again.

Further, when it is determined in step l007 that TI is lower than THI, the process proceeds to step 1008, and the flow rate adjustment valve 106
After opening the valve, the process returns to step 1001 again.

According to the above-described process, when the coolant temperature is low when starting the engine, the amount of coolant circulated to the engine 101 is reduced, so that the coolant temperature can rise more quickly. Therefore, the warm-up characteristics of the engine 101 can be improved. Furthermore, by increasing the engine wall temperature in a short period of time, exhaust efficiency can be improved, and fuel efficiency can also be improved.

Furthermore, when using the heater in winter or the like, the heater can be started up extremely quickly.

Furthermore, when the cooling water temperature rises and the thermostat 108 closes to block the radiator bypass passage 107, the cooling water flows through the radiator and the amount of heat dissipated from the radiator can be maximized, so the cooling water temperature is effectively reduced. Ru. Therefore, since the engine wall temperature can be reduced satisfactorily, engine output can be improved, and fuel efficiency can also be improved. Furthermore, by controlling the flow rate adjustment valve 106 according to the engine wall temperature and controlling the amount of cooling water flowing into the engine 101 and the amount of cooling water flowing bypassing the engine 101, even when the engine is at a transient high temperature,
The engine can be cooled well. Therefore, engine durability can be improved and fuel efficiency can also be improved.

Next, another embodiment will be described with reference to FIG.

First, regarding the configuration, the water pump 115 is driven directly by the engine, and the amount of circulating water increases as the engine speed increases.

Further, the flow rate adjustment valve 106 is set to valve throttle I, valve throttle ■, and completely closed.

The other configurations are the same as in the first embodiment.

Note that the water pump 115 may be driven by a hydraulic motor, and the discharge capacity of the water pump may be changed as necessary.

Here, the circulation flow rate Ve of the cooling water flowing through the engine 101 is
and a bypass flow 1vb of cooling water flowing through the bypass path 105.
The relationship between the two will be explained based on FIG.

Generally, the discharge capacity Vp of the water pump increases in proportion to the rotational speed Ne of the engine 101, as indicated by the symbol A in FIG. When the engine outlet side water temperature tw sensed by the water temperature sensor 113 is lower than the first set temperature Tw+, as shown by the symbol C in the figure, the water pump discharge flow rate is Half the amount of cooling water is circulated within the engine 101 while increasing in proportion to the engine speed Ne. The difference between line A and line C in the figure represents bypass flow 1vb. (Valve throttle 1) In this way, instead of circulating the entire water pump discharge flow rate to the engine 101, a reduced flow rate is circulated, so the cooling water temperature receives heat from the engine 101 and increases in a short period of time. This improves engine warm-up characteristics in cold and cold conditions. Note that when the heater is in use, the cooling water that has circulated through the engine 101 and the cooling water that has flowed through the bypass passage 105 are combined and then flow into the heater flow passage 109, so the amount of cooling water that flows to the heater core is not reduced, and the heater characteristics are There will be no decline.

When the engine outlet side water temperature tw exceeds the first set temperature Tw, the engine rotation speed Ne
When the rotational speed Ne is less than the set rotational speed Ne (for example, 1500 rpm), the flow rate adjustment valve 106 is fully closed, and the entire amount of the water pump discharge flow IVp is circulated within the engine 101. When the engine rotation speed Ne becomes equal to or higher than the set rotation speed Net, the opening degree of the flow rate adjustment valve 106 is set to a predetermined opening degree, and a part of the water pump discharge flow ff1Vp is bypassed,
The amount of cooling water circulating through the engine 101 is reduced.

(Valve Throttle ■) Next, the process executed by the ECU 200 for the above operation will be explained based on the program flowchart shown in FIG. The program shown in FIG.
It is executed from the time when the start is completed.

First, in step 2001, the cooling water temperature is detected based on the signal from the water temperature sensor 113, and if it is determined that the cooling water temperature Tw is lower than T1, the process proceeds to step 2002. In step 2002, the operation of the valve regulating valve 106 is set to valve throttle (13P), and the electric motor 114 is turned off. At this time, the cooling water is discharged by the water pump 115 to the other end of the second water conduit 104, the cylinder head of the engine 101, the cylinder block of the engine 101,
The other end side 103b of the first water conduit 103, the bypass passage 10
7 and is sucked in by the water pump 115 from one end side 104a of the first water conduit 104.

That is, at this time, since the amount of cooling water is relatively low, the amount of circulating water flowing through the engine 101 is kept low, and the amount of cooling water flowing through the engine 101 is kept low.
01 overcooling is prevented, and the coolant temperature rises well, so the engine is warmed up well. Note that at this time, the thermostat 108 is open, the cooling water bypasses the radiator 102 and flows through the radiator bypass path 107, and the electric motor 114 is not operating, so the radiator fan 112 does not rotate.

The process then proceeds to step 2003 again.

In step 2003, the flow rate adjustment valve 106 is closed, and then the process returns to step 2001 (in microsee units).

Further, in step 2001, the cooling water temperature Tw is Tw.

If it is determined that the above is the case, the process advances to step 2004.

If it is determined in step 2004 that the engine rotation speed N is lower than Ne based on the signal from the rotation speed sensor 205, the process returns to step 2001 via step 2003. Also, in step 2004, the engine speed N is set to N.
e. If it is determined that the above is the case, proceed to step 2005;
Then, when the electric motor 114 operates, the radiator fan 112 rotates, and the cooling water flowing inside the radiator 102 is forcibly cooled. In step 2005, flow 1
The operation of the regulating valve 106 is a valve throttle ■, and the electric motor 114
Turn on. That is, as the temperature of the cooling water increases, the amount of circulating water is increased to suppress the temperature rise of the cooling water. This maintains the cooling water at an appropriate temperature and cools the engine 101 well.

Note that since the thermostat 108 opens when the cooling water temperature Tw reaches about 80 to 90°C, the cooling water does not flow through the radiator bypass passage 107 but flows through the radiator 102.

Thereafter, the process proceeds to step 2006.

In step 2006, the temperature of the engine head wall is detected based on the signal from the wall temperature sensor 120, and when it is determined that the engine head wall temperature is equal to or higher than TNI (approximately 150 to 180 degrees Celsius), the process proceeds to step 2003. 2003
Now, the flow rate adjustment valve 106 is closed. Thereby, overheating of the wall temperature of the engine 101 can be prevented.

After that, the process returns to step 2001 again.

Further, when it is determined in step 2006 that To is lower than THI, the process proceeds to step 2007, and the flow rate adjustment valve 106
After opening the valve, the process returns to step 2001 again.

According to the above process, the engine rotation speed Ne is the set rotation speed N
e. In the following cases, by circulating the entire amount of cooling water from the cylinder head side of the engine 101, the wall temperature of the cylinder head can be more effectively reduced, and the rise in engine intake air temperature can be suppressed. . Therefore, as the engine output improves, the idle speed can be reduced, and fuel efficiency during idle can be improved.

At medium and high engine speeds when the engine speed Ne exceeds the set speed Ne, by appropriately controlling the circulation flow rate of the cooling water to the engine 101, the amount of cooling loss heat released from the engine 101 to the cooling water is reduced. It does not increase more than necessary depending on the operating state of the engine 101. Further, since the heat dissipation capacity of the radiator 102 does not change, the temperature of the cooling water flowing from the engine 101 decreases when the water temperature is in equilibrium (cooling loss heat amount = heat dissipation amount of the radiator), and the margin against overheating increases. Therefore, the net horsepower of the engine increases, and the engine output can be improved. Furthermore, since the cooling water cooled by the radiator 102 is circulated from the cylinder head side of the engine, the wall temperature of the cylinder head can be further lowered, which not only improves the filling efficiency of intake air but also improves the efficiency of the engine 101. The ignition timing can be advanced, and the output of the engine can be improved.

In this way, at least when the engine 101 rotates at a high speed, that is, when the discharge amount of the water pump 115 is large, the flow rate adjustment valve 106 is opened to bypass the engine 101, so that the wave path resistance on the discharge side of the water pump 115 is reduced. water pump 115
Even when the discharge amount is large, a large pressure difference does not occur between the suction side and the discharge side. Therefore, water pump 1
It is possible to suppress the occurrence of cavitation within 15.

Additionally, when the suction side pressure drops below a predetermined value and there is a risk of cavitation occurring, a pressure sensor is placed on the suction side of the water pump 115 to detect this, and the ECU 200 opens the flow rate regulating valve 106. command to increase the degree even further. As a result, the amount of cooling water that bypasses the engine 101 increases, and the flow path resistance on the discharge side of the water pump 115 can be reduced, thereby preventing the occurrence of cavitation.

The water pump 115 may be one that rotates under the driving force of the engine 101, or may be an electric or hydraulic water pump.Also, in order to increase the capacity of the water pump, a two-barrel water pump may be used. Alternatively, a conventional water pump and an electric water pump may be arranged in series or in parallel.

Furthermore, in the above embodiment, the first water conduit 103 is connected to the cylinder block side, and the second water conduit 104 is connected to the cylinder header side, so that the cooling water flows from the cylinder header side toward the cylinder block side. However, it may be made to flow from the cylinder block side toward the cylinder header side.

As the recirculation flow rate adjustment means, an electric water pump may be used instead of the above-mentioned flow rate adjustment valve, and the flow rate of cooling water flowing through the bypass path 105 can also be controlled by changing the rotation speed.

The above-mentioned cooling device enables more detailed engine cooling control by combining the rotation control of the radiator fan 112 and the control of ventilation systems such as the radiator inner ivy and the sub-radiator.

[Brief explanation of drawings]

Fig. 1 is a schematic circuit diagram showing one embodiment of the present invention, Fig. 2 is a configuration diagram showing the connection relationship between the ECU and each device, and Fig. 3 is the relationship between the engine rotation speed and the discharge capacity of the water pump. FIG. 4 is a characteristic diagram showing the relationship between cooling water temperature and water pump discharge capacity, FIG. 5 is a flowchart of a program executed in one embodiment of the present invention, and FIG. FIG. 7 is a flowchart of a program executed in another embodiment of the present invention, and FIG. 8 is a diagram showing a conventional embodiment. FIG. 101... Engine (internal combustion engine), 102... Radiator (heat exchanger), 103... First water conduit, 104
...Second water conduit, 105...Bypass path, 106.
...Flow rate adjustment valve (flow rate adjustment means), 113...Temperature sensor (temperature detection means), 115...Water pump (
circulation means).

Claims (5)

[Claims] (1) a heat exchanger that cools a heat exchange fluid that cools the internal combustion engine by exchanging heat with air; a first water conduit that guides the heat exchange fluid flowing out from the internal combustion engine to the heat exchanger; a second water conduit that causes the heat exchange fluid that has been heat exchanged by the heat exchanger to flow back to the internal combustion engine; a circulation means that is operated by the driving force of the internal combustion engine and circulates the heat exchange fluid; a bypass path that branches from the headrace and causes the internal combustion engine to bypass the fluid to be heat exchanged flowing through the second headrace; a temperature detection means for detecting a temperature according to the heat capacity of the internal combustion engine; A cooling device for an internal combustion engine, comprising: a flow rate adjusting means for adjusting the amount of fluid to be heat exchanged flowing through the bypass passage based on a signal, wherein a temperature according to a heat capacity of the internal combustion engine is lower than a first predetermined temperature. When the temperature corresponding to the heat capacity of the internal combustion engine is equal to or higher than a first predetermined value, the amount of the heat exchange fluid flowing into the internal combustion engine is increased. , and when the temperature corresponding to the heat capacity of the internal combustion engine is equal to or higher than a second predetermined value, or when the rotational speed of the internal combustion engine is equal to or higher than a predetermined value, actuate the flow rate control means to open the bypass passage; A method for cooling an internal combustion engine, characterized in that the fluid to be heat exchanged flowing through the second water conduit bypasses the internal combustion engine and flows into the bypass passage. (2) The internal combustion engine according to claim 1, wherein the circulation means circulates the heat exchange fluid by changing the discharge capacity of the heat exchange fluid independently of the rotation of the internal combustion engine. cooling method. (3) When the temperature corresponding to the heat capacity of the internal combustion engine is at least a second predetermined value, or when the rotation speed of the internal combustion engine is at least a predetermined value, and the cylinder head wall temperature of the internal combustion engine is at a predetermined value. 2. The method for cooling an internal combustion engine according to claim 1, wherein when the above temperature is reached, the bypass passage is shut off by the flow rate control valve and the heat exchange fluid is allowed to flow into the internal combustion engine. (4) Claim (2) characterized in that when the temperature according to the heat capacity of the internal combustion engine is lower than a first predetermined value, the circulation means is controlled to reduce the discharge capacity of the heat exchange fluid.
Method of cooling the internal combustion engine described. (5) When the temperature according to the heat capacity of the internal combustion engine is lower than the first predetermined value, the flow rate control valve is operated to open the bypass passage, and the heat exchange fluid flowing through the second conduit is transferred to the internal combustion engine. 2. The method for cooling an internal combustion engine according to claim 1, wherein the amount of heat exchange fluid flowing into the internal combustion engine is reduced by detouring the engine and causing the fluid to flow into the bypass passage.