JPH10131753A - Cooling device for water-cooled engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce friction loss of an engine, improve engine efficiency, and improve fuel consumption by raising a temperature of cooling water when an engine load is small, and lowering a temperature of cooling water when the engine load is large. SOLUTION: When an ignition switch is turned on, various kinds of information (a water temperature, pressure) are read in and memorized (S10). When an engine load is small, a temperature of cooling water is raised (for example 100 deg.C), and control is carried out by lowering the temperature of cooling water (for example to 80 deg.C) when the engine load is large (S20). It is judged whether the engine load is transferred from a low load to a high load or not (S30). When its judged result is 'Yes', it is judged whether the high load of the engine load is continued for a prescribed time or not (S40). When the judged result is 'Yes', a step is advanced to S40 in the case where the condition of the high load is continued for 30 minuets or more, and a water temperature of the high load is controlled. When the judged result is 'No' in S40, the engine load is transferred from the low load to the high load, a step is advanced to S60 for a prescribed time (30 minuets) in the high load condition, and the water temperature of the low load is controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling device for a water-cooled engine, and more particularly to a device for controlling the temperature of a cooling water in accordance with the load of a water-cooled engine (hereinafter, engine).

[0002]

2. Description of the Related Art Conventionally, a general engine cooling device is:
By controlling the heat radiation amount of the radiator, the engine cooling water temperature (hereinafter, cooling water temperature) is controlled to be an appropriate temperature.
Specifically, when the engine cooling water is at a predetermined temperature (for example, 10
When the temperature exceeds 0 ° C.), the engine coolant is cooled by flowing the coolant through the radiator. On the other hand, when the engine cooling water is lower than the predetermined temperature, the heat radiation amount of the radiator is set to 0, and the cooling water is caused to flow to a bypass circuit that bypasses the radiator.

[0003] The control of the amount of heat radiation in the radiator, that is, the switching to the radiator or the bypass circuit, is automatically performed by a thermostat as a temperature-sensitive valve. That is, when the temperature of the cooling water impinging on the thermostat falls below a predetermined temperature, the thermostat opens the bypass circuit. As a further development of such a cooling device, there is a device for controlling a cooling water temperature according to the engine load of an engine described in Japanese Patent Application Laid-Open No. 7-127752.

This conventional apparatus pays attention to the magnitude relation between an engine suction negative pressure (in manifold negative pressure) and an engine load,
When the engine load is large, the temperature is controlled to be low by circulating the cooling water between the engine and the radiator. On the other hand, when the engine load is small, the cooling water is prevented from hitting the thermostat, and the temperature is controlled to be high by sending the cooling water to the bypass circuit without opening the thermostat.

[0005]

According to the study by the present inventors, when the engine load is small, the cooling water is set to a high temperature (for example, 100 ° C.), and when the engine load is large, the cooling water is set to a low temperature. (Eg 80 °
C), it is known that friction loss (friction loss) of the engine is reduced, engine efficiency is improved, and fuel efficiency is improved. Also, it has been found that when the engine load is large, the cooling water is cooled to a low temperature, thereby improving the filling efficiency of the engine and suppressing knocking.

In the above-mentioned conventional apparatus, when the outside air temperature is high, for example, in summer, the vehicle waits for a signal (stop state).
When the vehicle suddenly starts, the engine load changes from a low load to a high load, so that the cooling water hits the thermostat, and the cooling water flows to the radiator. Then, the cooling water is cooled by the radiator, and the temperature rapidly decreases. And
If the high load condition is short, it takes a considerable amount of time to raise the temperature of the cooling water again when the engine load decreases, and the effect of improving fuel efficiency is not obtained much. I understood.

[0007]

Means for Solving the Problems In other words, the present inventors,
In normal vehicle running, as described above, the vehicle is suddenly started from a vehicle stop state such as waiting for a traffic light and the like, resulting in a high load. However, in such a case, it has been found that the conventional apparatus has a small effect of improving fuel efficiency in practical use.

Therefore, according to the first to fifth aspects of the present invention, the temperature control mechanism (5, 7, 13, 16, 18, 30)
Increases when the engine load detected by the engine load detecting means (23) is smaller than a predetermined value, and flows through the water-cooled engine (1) while the state larger than the predetermined value continues for a predetermined time. The cooling water temperature is controlled to be the first predetermined temperature, and when the state in which the engine load is higher than the predetermined value has passed for a predetermined time, the cooling water temperature flowing in the water-cooled engine (1) is lower than the second predetermined temperature.
It is characterized in that the temperature is controlled to be a predetermined temperature.

Thus, while the engine load is changed from a low load to a high load, and the high load state is maintained for a predetermined time, the temperature of the cooling water is increased by the temperature adjusting mechanism regardless of the high load to the first predetermined value of the high temperature. It is controlled so that Therefore, even if the engine load changes from a low load to a high load, the temperature of the cooling water hardly decreases and the high temperature state is maintained. As a result, the emission of the water-cooled engine can be reduced at the next low load, and the fuel efficiency can be improved.

On the other hand, when the engine load changes from a low load to a high load, and the state of the high load elapses for a predetermined time, the cooling water temperature is controlled by the temperature adjusting mechanism so as to reach the second predetermined low temperature. The emission of the water-cooled engine can be reduced even under load, and the fuel efficiency can be improved. In particular, in the invention according to claim 5, a cooling water temperature detecting means (21) for detecting a temperature of cooling water flowing in the water-cooled engine (1), an outside air temperature detecting means (20) for detecting an outside air temperature, and a radiator (2). ), And a cooling fan driven when the cooling water temperature detected by the cooling water temperature detecting means (21) is higher than a predetermined set temperature, and the flow rate adjusting means (13, 16,
30) The set temperature is set to be lower as the amount of cooling water to the radiator (2) adjusted by the radiator (2) is smaller.

Thus, by reducing the amount of cooling water to the radiator, when the temperature of the cooling water is maintained at a high temperature, the smaller the amount of cooling water, the more difficult it is to drive the cooling fan 5. As a result, the cooling water temperature can be easily maintained at a high temperature.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention; (First Embodiment) FIG. 1 shows a cooling water circuit 200 of a water-cooled engine (hereinafter, referred to as an engine) 1 for a vehicle. A radiator 2 is provided in the cooling water circuit 200 and cools the cooling water flowing out of the engine 1 by radiating heat.
This is a water pump that sucks cooling water flowing out of the engine 1 and sends it to the engine 1 under pressure. In addition, this water pump 3
Is of a viscous type (not a volume type).

Numeral 5 is a cooling fan for blowing air (outside air) toward the radiator 2.
Are driven by a fan motor 7. In the present embodiment, the cooling fan 5 is driven when the normal cooling water temperature becomes equal to or higher than a predetermined temperature (92 ° C.). Reference numeral 100 denotes a radiator water channel for returning cooling water flowing out of the engine 1 to the engine 1 via the radiator 2. Reference numeral 101 denotes a bypass water passage (temperature-sensitive water passage) for returning the cooling water flowing out of the engine 1 to the engine 1 by bypassing the radiator 2. The bypass channel 101 is connected to the radiator 2 of the radiator channel 100.
The cooling water outlet side of the cooling water outlet joins the radiator water channel 100, and a well-known thermostat (temperature-sensitive operation valve) 13 that opens and closes a valve body in accordance with the cooling water temperature is disposed at the junction 100a. .

In the bypass water passage 101, the cooling water flowing through the bypass water passage 101 in the confluence portion 100a is guided to the temperature sensing portion (a wax box filled with a thermally expandable wax material) 13a of the thermostat 13. At the junction 100a. The temperature sensing part 13a senses the temperature of the cooling water discharged from the engine 1. Since the thermostat 13 has the valve body 13b disposed on the radiator 2 side from the junction 100a to open and close the radiator water channel 100, even if the thermostat 13 is closed, the bypass water channel 101 is Communication is possible. The temperature sensing portion 13a is adapted to be contacted with cooling water flowing through the radiator channel 100 and the bypass channel 101.

Although the thermostat 13 is well known, its operation will be briefly described. For example, temperature sensing part 1
When the temperature of the cooling water corresponding to 3a becomes higher than, for example, 83 ° C., it operates so as to extend upward in the drawing of the temperature sensing portion 13a, close the bypass water passage 101 at the valve body 13c, and open the radiator water passage 100. On the other hand, when the temperature of the cooling water hitting the temperature sensing portion 13a becomes lower than, for example, 83 ° C., the temperature sensing portion 13a extends downward in the drawing to open the bypass water passage 101 at the valve body portion 13c and operate to close the radiator water passage 100. .

Thus, the thermostat 13 adjusts the amount of cooling water flowing through the radiator channel 100 and the bypass channel 101. The bypass water passage 101 is provided with a flow control valve 16, which is a flow control means for adjusting the amount of cooling water flowing through the bypass water passage 101, on the upstream side of the thermostat 13. In addition,
This flow control valve 16 is actually a cross-sectional view in FIG. 1, but hatching is omitted here.

In this embodiment, the flow control valve 16 comprises a resin-made valve housing 16a and a rotary valve body 16b rotatably installed in the valve housing 16a. A control channel 16c is formed in the valve body 16b as shown in the figure. When the valve body 16b rotates, the flow area of the bypass water passage 101 is adjusted by the control flow passage 16c. By the way, 16
d is a sealing member made of a fluororesin that seals a gap between the valve body 16b and the valve housing 16a.

A shaft (not shown) is integrally formed at one end of the valve body 16a in the direction of the rotation axis, and an actuator 17 such as a servo motor as a driving means is provided on the shaft.
Are connected. Thus, the valve body 16a is driven to rotate by the actuator 17. The actuator 17 is controlled by a control device 18 as shown in FIG. 2. The control device 18 has an outside air temperature sensor 20 for detecting the temperature outside the vehicle compartment (outside air temperature), A water temperature sensor 21 for detecting a cooling water temperature (or a cooling water temperature in the engine 1), a pressure sensor (engine load detecting means) 23 for electrically detecting a suction negative pressure of the engine 1, and detecting an operating state of the engine 1. Signal from the ignition switch 24 for inputting the signal.

The control device 18 controls the water temperature sensor 20
The actuator 17 and the cooling fan 7 are controlled in accordance with a preset program based on a signal from the air conditioning sensor 22. The water temperature sensor 21 is a thermistor type having excellent responsiveness (time constant is about 1 to 2 seconds). The control device 18 has a position detecting function such as a potentiometer so that the valve opening of the valve body 16b can be determined.

Next, the control device 1 according to the present embodiment will be described.
8 will be described with reference to the flowchart of FIG. This flowchart is executed when the ignition switch is turned on. First, in step S10, the water temperature sensor 21 and the pressure sensor 23 are read and stored as various information.

Next, in step S20, as described above, in order to improve the fuel efficiency, when the engine load is small, the cooling water is set to a high temperature (for example, 100 ° C.) and the engine load is controlled in accordance with the engine load. When the cooling water is large, the cooling water is set to a low temperature (for example, 80 ° C.). Specifically, first, in the present embodiment, the absolute value Pin of the suction negative pressure detected by the pressure sensor 23 is set to a predetermined value (in the present embodiment, 26 k
If it is higher than pa), the engine load is small and the load is low. If the absolute value Pin of the suction negative pressure is smaller than 26 kpa, it is determined that the engine load is large and the load is high.

When the engine load is low,
As low-load water temperature control, the valve opening of the flow control valve 16 shown in FIG. 1 is reduced so that the amount of cooling water flowing through the bypass water passage 101 is reduced. As a result, the amount of cooling water flowing through the bypass water passage 101 decreases, so that the operation of the thermostat 13 becomes slow, and it becomes difficult to open the radiator water passage 100. As a result, the amount of cooling water flowing through the radiator 2 is small, and the amount of heat radiation in the radiator 2 is small.
The cooling water temperature is controlled to be high (for example, 100 ° C.).

On the other hand, when the engine load is high, the flow control valve 16 is fully opened as shown in FIG. 1 for low load water temperature control. Thus, the amount of cooling water flowing through the bypass water passage 101 becomes larger than when the engine load is low. Therefore, the cooling water hardly hits the temperature sensing part 13a, the operation of the thermostat 13 becomes sensitive, and the amount of cooling water flowing through the radiator water channel 100 increases. As a result, the cooling water is less likely to be sent to the radiator 2, so that the amount of heat radiation in the radiator 2 increases, and the cooling water temperature is controlled to be low (for example, 80 ° C.).

Next, in step S30, it is determined whether the engine load has changed from a low load to a high load. Specifically, as described above, the absolute value Pin of the suction negative pressure is 26 kp.
It is determined whether or not the value has become smaller since the time is higher than a. This is, for example, when the vehicle suddenly starts from a signal waiting state (stop state) as described above. And step S
If the determination result in 30 is YES, the process proceeds to step S40, and if NO, the process proceeds to step S70.

In step S40, the state in which the engine load is high is maintained for a predetermined time (30 seconds in this embodiment).
It is determined whether or not it has continued (predetermined time determination means). That is, in step S40, together with step S30, it is determined whether or not the engine load has changed from a low load state to a high load state, and whether or not the high load state has continued for a predetermined time. If the result of this determination is YES, that is, if the state of high load has continued for 30 seconds or longer, step S50
Then, the above-mentioned high-load water temperature control is performed.

On the other hand, if the decision result in the step S40 is NO,
In other words, if the engine load changes from a low load to a high load, and the state of the high load continues for a predetermined time (30 seconds), the process proceeds to step S60, and the above-described low load water temperature control is performed. That is, in this embodiment, when the engine load changes from a low load to a high load, the low load water temperature control is performed so that the cooling water temperature becomes high even when the engine load is high, and the flow control valve 16 is set to the position shown in FIG. From the indicated opening degree, the bypass waterway 10
The aperture is set so that 1 is reduced.

Such an idea is that, as described above, in normal vehicle running, the vehicle suddenly starts from a vehicle stop state such as waiting for a traffic light and becomes a high load, and this high load is only for a short time, followed by a low load. It is based on the prediction that the frequency is very high and the load will always be low after a short period of high load. As a result, the load of the engine changes from a low load to a high load, and for a short time in the high load state, the cooling water temperature is controlled to the low load water temperature regardless of the high load, and the cooling water temperature is changed to the low temperature state. Will be sustained. As a result, when the load becomes low next time, the temperature of the cooling water is maintained at a high temperature, so that the emission of the engine 1 at this time can be reduced and the fuel efficiency can be remarkably improved.

On the other hand, in this embodiment, when the high load state lasts (elapses) for a predetermined time, for example, when the vehicle runs on a long uphill, the high load water temperature control is performed as shown in step S50, and the cooling water is cooled to a low temperature. In this case, the emission of the engine 1 at this time can be reduced, and the fuel efficiency can be improved. By the way, as described above, the amount of cooling water flowing through the bypass water passage 101 is reduced by the flow control valve 16, and at this time, the radiator water passage 100 is slightly opened depending on the cooling water temperature hitting the temperature sensing portion 13a.

Therefore, when the high-temperature state is maintained without lowering the cooling water temperature as the low-load water temperature control regardless of the high load as described above, the cooling water flows through the radiator channel 100, and at this time, the cooling water temperature decreases. When the temperature is higher than 92 ° C. and the cooling fan 5 is driven, the temperature of the cooling water tends to decrease. As a result, although the cooling water temperature is desired to be maintained at a high temperature, the ventilation of the radiator 2 of the cooling fan 5 promotes a decrease in the cooling water temperature.

Therefore, in this embodiment, when the low load water temperature control is performed, the process proceeds to step S70 (first stage), and the set temperature Tf at which the cooling fan 5 is driven is reset. Specifically, as shown in FIG. 4, the set temperature Tf is set to be smaller as the valve opening of the valve body 16a of the flow regulating valve 16 is smaller, that is, as the amount of cooling water flowing through the radiator 2 is smaller.

As described above, by reducing the amount of cooling water to the radiator by narrowing the bypass water passage 101 as described above, the cooling water flows into the radiator 2 when the temperature of the cooling water is maintained at a high temperature without decreasing the temperature. However, it becomes difficult to drive the cooling fan 5. As a result, the cooling water temperature can be easily maintained at a high temperature. Then, the process further proceeds to step S80, and as a second stage, the set temperature Tf reset in step S70 is set again by the following equation (1).

[0032]

## EQU00001 ## True set temperature TF = Tf + .DELTA.Tf 'Specifically, as shown in FIG. 5, .DELTA.Tf' becomes positive when the detected temperature Tam of the outside air temperature sensor 20 becomes high as shown in FIG. It is set so that it becomes negative. The reason for setting ΔTf ′ in this manner is that the temperature detected by the outside air temperature sensor 20 is slightly affected by the outside air temperature. That is, the detection value of the outside air temperature sensor 20 tends to be higher than the actual cooling water temperature when the outside air temperature is high, and tends to be lower than the actual cooling water temperature when the outside air temperature is low.

Therefore, for example, when the outside air temperature is high,
When the cooling water temperature is set to 100 ° C. by performing the above-described low load water temperature control, it is possible to prevent the cooling fan 5 from being driven early. As a result, the cooling water temperature can be accurately controlled. Note that ΔTf ′
May be set in the actual vehicle test in consideration of the influence of the outside air temperature according to the vehicle.

(Second Embodiment) In the first embodiment,
In this embodiment, the thermostat 13 and the flow control valve 16 are eliminated as shown in FIG.
Further, a cooling water amount adjusting valve 30 for adjusting the amount of cooling water flowing through the radiator 2 is provided. The components having the same functions as those of the first embodiment are denoted by the same reference numerals. FIG. 7 is a cross-sectional view taken along the line AA of FIG.
0 is shown as a whole. ). The cooling water amount adjustment valve 30 shown in FIG. 6 is actually a cross-sectional view, but is not hatched here.

The cooling water amount adjusting valve 30 is provided in the radiator water channel 1.
The valve 30a is driven by a disc-shaped valve 30a that opens and closes and a servo motor 31 that is a driving unit that drives the valve 30a. And this servo motor 31
As shown in FIG. 2, the valve opening is controlled by the controller 18 based on the detection values of the outside air temperature sensor 21 and the pressure sensor 23.

Next, the control contents of the cooling water amount adjusting valve 30 will be described with reference to a flowchart shown in FIG. Note that FIG.
Shows the control contents of the flow rate adjusting valve 16 and the cooling fan 5 in the first embodiment. However, the concept of the present embodiment is the same as that of the first embodiment, so that it is used as it is. I do. First, step S10,
20 is the same as that of the first embodiment, except that step S
The low load water temperature control and the high load water temperature control at 20 are slightly different.

That is, in step S20, when the engine load is low, the valve opening degree of the valve body 30a of the cooling water flow control valve 30 shown in FIG. Squeeze so that there is less. This reduces the amount of cooling water flowing through the radiator water channel 100, so that the amount of heat radiation in the radiator 2 decreases, and the cooling water temperature is controlled to a high temperature (for example, 100 ° C.).

On the other hand, when the engine load is high, the valve body 30a of the cooling water amount adjusting valve 30 is used as low load water temperature control.
Is set to a fully open state as shown in FIGS. As a result, the amount of cooling water flowing through the radiator channel 100 becomes larger than when the engine load is low. Therefore,
The amount of heat radiation in the radiator 2 increases, and the cooling water temperature is controlled to be low (for example, 80 ° C.).

Next, steps S30 to S80 are the same as those in the first embodiment, and a description thereof will be omitted. By doing so, the same effect as in the first embodiment can be obtained. In the present embodiment, the cooling water amount adjusting valve 3
By providing 0 in the radiator waterway 100, the thermostat 13 can be eliminated, and cost reduction can be realized by reducing the number of parts.

(Other Examples) In each of the above embodiments, the valve opening of the flow control valve 16 and the cooling water control valve 30 is switched in two stages between the low load water temperature control and the high load low temperature control. As the value becomes larger, in other words, as the absolute value of the suction negative pressure Pin detected by the pressure sensor 23 decreases, the switching may be performed in more stages or may be performed continuously.

In each of the above embodiments, the flow control valve 1
Although the low load water temperature control and the high load low temperature control are switched by the control unit 6 and the cooling water amount control valve 30, for example, the following may be used. First, instead of omitting the flow control valve 16 in FIG. 1, an electric heater as a heating means is disposed in the thermosensitive section 13 a of the thermostat 13. The on / off (energization / interruption) of the electric heater is controlled by the control device 18. Also, the temperature sensing unit 13
The expansion start temperature of “a” is set higher than in the above embodiments. For example, in the low-load water temperature control, the cooling water temperature is maintained at a high temperature by turning off the electric heater in order to raise the cooling water temperature. On the other hand, in the high-load water temperature control, in order to lower the cooling water temperature, by turning on the electric heater, the thermostat 13 is operated earlier to open the radiator waterway 100. Thereby, the cooling water temperature is maintained at a low temperature.

In the above embodiment, when the engine load is changed from a low load to a high load, and the state of the high load is maintained for a predetermined time or more, the set temperature of the cooling fan 5 may be simply increased. . In addition, a threshold value of 26 kp, which is a threshold value for performing low-load water temperature control or high-load water temperature control.
As is well known, a (absolute value of the suction negative pressure Pin) is an index indicating the magnitude of the engine load, and is not limited to 26 kpa, but is appropriately determined according to the engine displacement, the output characteristics of the engine 1, and the like. Is what is done.

In each of the above embodiments, the means for detecting the engine load uses the suction negative pressure Pin of the engine 1. Instead, the engine load may be detected based on, for example, the accelerator opening or the vehicle speed. You may do it.

[Brief description of the drawings]

FIG. 1 is a diagram showing a cooling water circuit 200 of an engine 1 according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a control device 18 according to the first and second embodiments of the present invention.

FIG. 3 is a flowchart showing control contents of a control device 18 according to the first and second embodiments of the present invention.

FIG. 4 is a set temperature Tf in the first and second embodiments.
FIG. 5 is a diagram showing a correlation between the load and the engine load.

FIG. 5 is a set temperature Tf in the first and second embodiments.
FIG. 6 is a diagram showing a correlation between the correction term Tf ′ of FIG.

FIG. 6 is a diagram showing a cooling water circuit 200 of the engine 1 according to a second embodiment of the present invention.

FIG. 7 is a sectional view taken along line AA of FIG. 6;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Water-cooled engine, 2 ... Radiator, 5 ... Cooling fan, 7 ... Fan motor 13 ... Thermostat, 16 ... Flow control valve, 18 ... Control device 23 ... Pressure sensor, 30 ... Cooling water amount control valve

Claims (6)

[Claims] An engine (1) is provided in a water-cooled engine (1) and a cooling water circuit (200) of the water-cooled engine (1).
A radiator (2) for cooling the cooling water by heat radiation; an engine load detecting means (23) for detecting an engine (1) load of the water-cooled engine (1); A temperature control mechanism (5, 7, 1) for controlling the amount of heat radiated by the radiator (2) so that the flowing cooling water temperature becomes higher as the engine load detected by the engine load detecting means (23) becomes smaller.
A cooling device for a water-cooled engine provided with the temperature control mechanism (5, 7, 13, 16, 18, 30, 30).
The engine load detected by the engine load detecting means (23) increases when the engine load is smaller than a predetermined value, and while the state larger than the predetermined value continues for a predetermined time, the water-cooled engine (1) The temperature of the cooling water flowing through the water-cooled engine (1) is controlled so that the temperature of the cooling water flowing through the water-cooled engine (1) becomes equal to the first predetermined temperature. A cooling device for a water-cooled engine, wherein the cooling device controls the temperature to be a second predetermined temperature lower than the predetermined temperature. 2. A water-cooled engine (1) and an engine (1) in a cooling water circuit (200) of the water-cooled engine (1).
A radiator (2) for cooling the cooling water by heat radiation; an engine load detecting means (23) for detecting an engine (1) load of the water-cooled engine (1); The engine load detected by the engine load detecting means (23) is larger than a predetermined value so that the cooling water temperature becomes a first predetermined temperature when the engine load detected by the engine load detecting means (23) is smaller than a predetermined value. And a temperature control mechanism (5, 7, 13, 16, 18, 18, 3) for controlling the amount of heat radiated by the radiator (2) so as to reach a second predetermined temperature higher than the first predetermined temperature.
0), wherein the temperature control mechanism (5, 7, 13, 16, 18, 30) is provided.
The engine load detected by the engine load detecting means (23) increases when the engine load is smaller than a predetermined value, and while the state larger than the predetermined value continues for a predetermined time, the water-cooled engine (1) The cooling water temperature flowing through the water-cooled engine (1) is controlled such that the temperature of the cooling water flowing through the water-cooled engine (1) is controlled to be equal to the first predetermined temperature. 2. A cooling device for a water-cooled engine, wherein the cooling device controls the temperature to be a predetermined temperature. 3. A cooling water circuit (200),
Flow rate adjusting means (13, 16, 30) for adjusting the amount of cooling water discharged from the water-cooled engine (1) and sent to the radiator (2); and the temperature control mechanism (5, 7, 13, 16) , 18, 30)
Is constituted by the flow rate adjusting means (13, 16, 18, 30). The flow rate adjusting means (13, 16, 18, 30) is provided with an engine load detected by the engine load detecting means (23). Is larger than the predetermined value from when the predetermined value is smaller than the predetermined value, and while the state larger than the predetermined value is maintained for a predetermined time, the amount of cooling water flowing through the radiator (2) is adjusted so that the cooling is performed. The water temperature is controlled to be the first predetermined temperature, and when the engine load is larger than the predetermined value when the predetermined time has elapsed, the cooling water temperature is increased by increasing the amount of cooling water flowing through the radiator (2). 2 is controlled so as to reach the second predetermined temperature.
Or a cooling device for a water-cooled engine according to 2. 4. A cooling water circuit (100),
A radiator channel (100) for guiding the cooling water flowing out of the water-cooled engine (1) to the radiator (2); a cooling water disposed in the radiator channel (100) and discharged from the water-cooled engine (1). A temperature-sensitive operating valve (13) having a temperature-sensing part (13a) for sensing temperature, for opening and closing the radiator channel (100) in accordance with the cooling water temperature sensed by the temperature-sensing part (13a); A temperature-sensitive water channel (101) for guiding cooling water discharged from the water-cooled engine (1) to the temperature-sensitive portion (13a); and the flow rate adjusting means (13, 16, 30) includes the radiator water channel (100). ) And the thermosensitive water channel (10
4. The cooling device for a water-cooled engine according to claim 3, wherein the amount of cooling water flowing through 1) is adjusted. 5. A cooling water temperature detecting means (21) for detecting a temperature of a cooling water flowing in the water-cooled engine (1), an outside air temperature detecting means (20) for detecting an outside air temperature, and toward the radiator (2). A cooling fan driven when the cooling water temperature detected by the cooling water temperature detecting means (21) is higher than a predetermined set temperature, and the flow rate adjusting means (13, 16, 30) The cooling device for a water-cooled engine according to any one of claims 2 to 4, wherein the set temperature is set so as to decrease as the amount of cooling water to the radiator (2) adjusted by) is reduced. . 6. A cooling water temperature detecting means (21) for detecting a temperature of a cooling water flowing in the water-cooled engine (1), an outside air temperature detecting means (20) for detecting an outside air temperature, and toward the radiator (2). A cooling fan (5) driven when the cooling water temperature detected by the cooling water temperature detection means is higher than a predetermined set temperature, and an outside air temperature detected by the outside air temperature detection means (20). The cooling device for a water-cooled engine according to any one of claims 1 to 5, wherein the higher the temperature, the higher the set temperature.