JPH0323312A - Cooling device of engine - Google Patents

Abstract

PURPOSE:To restrain the change of the temperature of cooling water following the change of the opening valve temperature and to stabilize the heating temperature by detecting and keeping the lowest outside air temperature from the start of driving and by stopping the change of the opening valve temperature of a thermo-valve when the lowest outside air temperature is below a specified value. CONSTITUTION:A thermo-valve TV is arranged at one end opening part of a by-pass passage 25 which by-passes a radiator 4 and connects through a plural number of cooling water passages 6, 13. Then the thermo-valve TV is driven and controlled by a control means C through an actuator 35 on the basis of a detection signal from a load detection means A against an engine E. In this case, the lowest outside air temperature from the start of driving is detected and maintained by an outside air temperature input means D on the basis of a detection signal from an outside air temperature detection means B. Accordingly, when the lowest outside air temperature is lower than a specified value, a regulation signal is input from a regulation means F to the control means C to stop the drive of the actuator 35.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an engine cooling system equipped with a thermovalve having a plurality of valve opening temperature settings.

(Conventional technology) Traditionally, engine cooling systems have been used to maintain the cooling water temperature in a relatively low range during high-speed, high-load operation to ensure engine reliability, and to compare the cooling water temperature during other low-load operations. In order to improve fuel economy by reducing the harmful components in the exhaust gas by setting the target high temperature, the valve opening temperature is different, as seen in Japanese Patent Publication IM {54-9865. In addition to having multiple thermo valves in series, an actuator is installed to close the cooling water passage to the radiator side by the low temperature thermo valve at low loads, and at low loads, the cooling water temperature is raised to the opening temperature of the high temperature thermo valves. This technique is publicly known.

In the above cooling system, a bypass passage that bypasses the radiator is branched from a passage leading from the outlet of the engine's water jacket to the radiator port, and a low-temperature thermovalve and a high-temperature thermovalve are interposed in series in this branching part. The actuator is interposed between the high-temperature thermovalve and the bypass passage, and under low load conditions, unless the high-temperature thermovalve opens, cooling water will not flow to the radiator and the cylinder will not flow. This improves fuel efficiency by increasing the temperature and combustion efficiency, and also suppresses the emission of unburned components such as HC.

Furthermore, a technique for configuring a heater device for indoor heating of a vehicle in which a heater passage having a heat exchange section is connected to the water jacket of the engine, bypassing the radiator, is also well known.

(Problem to be Solved by the Invention) However, in an engine cooling system equipped with a thermovalp whose valve opening temperature is variable according to the operation of the actuator as described above, the temperature of the cooling water changes as the actuator operates according to the load condition. Since the temperature changes greatly, the heat radiation amount of the heater fluctuates in response to this temperature change, resulting in a large change in the heating temperature.

In other words, under low load conditions, by operating the actuator so that the opening temperature of the thermovalve is on the high temperature side, the temperature at which the thermovalve opens and the cooling water from the engine flows to the radiator increases. .

Then, the temperature of the cooling water circulating through the water jacket of the engine increases, and since this cooling water passes through the heater passage as it is, the amount of heat dissipated in the heat exchange section increases and the heating temperature increases. On the other hand, when the actuator is in a high load state and the actuator operation is reduced to M, the opening temperature of the thermovalve becomes lower temperature, and the coolant whose temperature has been lowered by circulating the heat through the radiator is circulated to the engine. , the temperature of the cooling water flowing through the heater passage also decreases, and the heating temperature also decreases. As described above, the cooling water temperature changes by, for example, about 15° C. depending on the driving state, and the heating temperature fluctuates greatly during driving.

Therefore, in order to address the above-mentioned problems, the present invention is designed to stop changing the valve opening temperature of the thermovalve in a low outside temperature state where the outside temperature is below a predetermined value, that is, in a temperature state where the heater is used. However, if the outside temperature is not detected accurately, there is a risk that a large change in heating temperature similar to the above may occur.

Normally, the outside temperature sensor used for engine air-fuel ratio control etc. detects based on the signal of the intake air temperature sensor installed in the intake air amount sensor part of the intake passage. is greatly affected by temperature changes in the engine room, and when the vehicle is stopped after driving at high speed, the engine room temperature increases significantly, resulting in a detected value that deviates significantly from the actual outside temperature. If this value is used as is, the detected temperature will be high regardless of the outside temperature or the conditions in which the paper heater is used, and the actuator will start operating, causing a change in the heating temperature.

In view of the above-mentioned circumstances, the present invention aims to improve fuel efficiency during low-negative 6th generation by changing the opening temperature of the thermovalve according to the load condition.Changes in the temperature of the cooling water flowing through the heater passage under low outside temperature conditions It is an object of the present invention to provide an engine cooling device that suppresses heating performance and stabilizes heating performance.

(Means for Solving the Problems) In order to achieve the above object, the cooling device of the present invention includes a heater passage including a heat exchange section and arranged to bypass a radiator, and a thermovalve having a plurality of different valve opening temperature settings. and,
an actuator that operates to change the opening temperature of the thermovalve to a higher temperature side; and an actuator control means that changes the actuator to a higher temperature side in a low load state depending on the load state of the engine; , an outside temperature detection means for detecting the outside temperature from intake air temperature, etc.; an outside temperature input means for receiving a signal from the outside temperature detection means to detect and hold the lowest outside temperature since the start of operation; and a signal from the outside temperature input means. In response to this, the actuator is configured to include a regulating means for stopping the operation of the actuator, especially when the lowest outside temperature is below a predetermined value.

As shown in FIG. 1, the basic configuration of the present invention is shown in FIG. The heat is radiated from the radiator 4 and circulated through the second cooling water passage 13 to the engine E via the water bomb 14. Further, a bypass passage 25 is installed which bypasses the radiator 4 and communicates the first cooling water passage 6 and the second cooling water passage 13.
A thermovalve TV having a plurality of different valve-opening temperature settings is disposed at the branching point with the valve opening temperature. The thermobulp TV
is the first valve to the radiator 4 side below the set valve opening temperature.
The cooling water passage 6 is closed, the bypass passage 25 is opened, and the cooling water is made to viscous through the bypass passage 25. The thermovalve TV is provided with an actuator 35 that changes the valve opening temperature to a higher temperature.

Further, a heater passage 47 that bypasses the radiator 4 and communicates with the second cooling water passage 13 flowing through the radiator 4 is connected to an intermediate part of the cooling water circulating in the engine E, A heat exchange section 48 for heat radiation is interposed in the.

A load detection means A for detecting the load state of the engine E is provided, and an actuator control means C for controlling the operation of the actuator 35 operates the actuator 35 to a high temperature side in a low load state according to the load state of the engine E. do.

Further, an outside temperature detection means B is provided for detecting the outside temperature from the intake air temperature, etc., and the outside temperature input means D, which receives a signal from the outside temperature detection means B, detects and holds the lowest outside temperature since the start of operation. A signal from the outside temperature input means/device D is outputted to the regulating means F, and when the lowest outside temperature is lower than a predetermined value, a signal is outputted to the actuator control means C to stop the operation of the actuator 35. It is composed of

(Function) In the engine cooling system as described above, the outside temperature detection signal such as the intake air temperature is detected and held by the outside temperature input means, and the minimum outside temperature from the start of operation is detected and held, and a predetermined value is set based on this minimum outside temperature. Since there is a possibility of using a heater in the following low outside temperature Samurai, the operation of changing the valve opening temperature of the thermovalve is stopped, and even if the load condition changes, the valve opening temperature can be changed without operating the actuator. The system aims to stabilize the heating temperature by suppressing large fluctuations in the cooling water temperature caused by the heating.

In addition, even if the engine room temperature rises after high-speed driving by maintaining the minimum outside temperature, if the minimum outside temperature up to that point is below a predetermined value, the actuator will stop operating, and the initially detected temperature Even if the temperature is high, the operation of the actuator is stopped as the minimum temperature thereafter decreases, and fluctuations in the warm-up temperature are suppressed by accurately determining the low outside temperature state.

On the other hand, when the minimum outside temperature is higher than the predetermined value, the actuator is operated under low load conditions, the thermovalve opening temperature is changed to the high temperature side, the temperature of the cooling water circulating through the engine becomes high, and the combustion Improve fuel efficiency by increasing efficiency. In addition, under load conditions, the thermovalve opening temperature is set to a low temperature side, and cooling water flows into the radiator, increasing the amount of cooling and maintaining the engine temperature within a predetermined range.

Ensures axiality.

(Example) Embodiments of the present invention will be described below along with the drawings.

FIG. 2 shows a schematic configuration of an engine cooling system in one example. This embodiment is an example in which two thermo valves with different set temperatures are provided.

Engine E (two-cylinder rotary piston engine) is equipped with a water jacket 2 on the outer periphery of an engine body 1 (casing) consisting of a rotor housing 1a and a side housing 1b. 2 flows in the axial direction from one end to the other, turns back at the other end, and returns to the one end.

The outlet portion 3 of the water jacket 2 is connected to the first cooling water passage 6
It is connected to the inlet 5 of the hot tank 23 of the radiator 4 by. From the outlet 12 of the lower tank 24 of the radiator 4 to the water jacket 2 of the engine body 1
The artificial parts 17 are connected by a second cooling water passage 13. A water pump 14 is disposed in the engine side portion of the second cooling water passage 13, and cooling water is circulated by the water pump 14.

Two parallel opening passages 7 and 8 are formed in the middle of the first cooling water passage 6, one passage 7 having a high temperature thermo valve 9 and the other passage 8 having a low temperature thermo valve 10. are arranged respectively. The high-temperature thermovalve 9 opens at a predetermined high temperature (for example, about 97°C) or above, while the low-temperature thermovalve 10 opens at a temperature slightly lower than this (for example, about 8°C).
The valve is set to open at temperatures above 2°C.

Furthermore, the parallel passage 7 is provided between the first cooling water passage 6 and the second cooling water passage 13 by bypassing the radiator 4.
．． A bypass passage 25 is provided that connects the upstream side of water bomb 8 and the upstream side of water bomb 14 . This bypass passage 2
5 has an end connected to the first cooling water passage 6 branched into a small diameter bypass passage 25a and a large diameter bypass passage 25b.

The small diameter bypass passage 25a is the first cooling water passage 6.
On the other hand, the large-diameter bypass passage 25b is connected and opened to the high temperature thermovalve 9, and the large diameter bypass passage 25b is similarly opened and connected to the low temperature thermovalve 10.

The wax pellets 29 and 29 of both thermovalves 9 and 10 move up and down in response to temperature changes.

The wax pellets 29 and 29 in the high and low temperature thermovalve 9 and 10 have a parallel passage 7 on the upper end side.
．． Valve bodies 9a, 10a for opening and closing the valves 25a, 25a, 25a, 25a, 25a, 25a, 25a, 25b, 25a, 25b, 25b, 25b, 25b, 25b, 25b, 25b, 25a, 25a, 25a, 25a, 25a, 25a, 25a, . A second on-off valve 9b and a third on-off valve tob are attached to open and close the openings of 25b, respectively, and the wax pellets 29.29 are urged by springs 33.33 in the direction of closing the valve bodies 9a, 10a.

The wax pellets 29.29 are activated by springs 33.3 when the cooling water temperature rises above the respective installation temperatures.
3, and after the valve body 9a or 10a opens the parallel passage 7 or 8 which was in the closed state, the second or third opening/closing valve 9b, 10 opens as the temperature further increases.
b closes the small diameter or large diameter bypass passages 25a, 25b.

Furthermore, a first on-off valve 34 is disposed in the open passage 8 on the downstream side of the low-temperature thermovalve 10, and this first on-off valve 34 is attached to the tip of an operating shaft 36 of a negative pressure actuator 35. The negative pressure chamber 37 of the actuator 35 has a negative pressure introduction passage 38 whose one end communicates with the intake manifold 11.
is connected, and the first on-off valve 3 is connected by the negative pressure introduction passage 38.
4 is introduced, and the opening operation of the first on-off valve 34 is caused by the negative pressure chamber 3 of the actuator 35.
7 is popularly released and is performed by its spring 39.

A three-way solenoid valve 40 is provided in the middle of the negative pressure introduction passage 38.
, a delay valve 41, and a check valve 42 are provided.

Further, in the radiator 4, two motor-driven first and second electric fans 45 and 46 are disposed vertically on the back of the cooling core. Further, a heater passage 47 is provided which communicates with the second cooling water passage 13 downstream of the radiator 4 from an intermediate portion of the water jacket 2 of the engine body 1, and a heat exchanger 48 for heat radiation is provided in the middle of the heater passage 47.
is interposed.

The controller 5 controls the operation of the three-way solenoid valve 40 of the negative pressure introduction passage 38 for the actuator 35 and the rotational drive of the first electric fan 45 of the radiator 4.
This is done by a drive signal from 0 (control circuit). The controller 50 uses the following as a detection signal for its control:
A fuel injection/l pulse signal Ps that detects the load condition of the engine E, an engine rotation speed signal Ne, an outside temperature signal Ta that detects the temperature of the intake air by a temperature sensor (not shown) installed in the intake passage, Water temperature signal Tw from a water temperature sensor 51 installed in the first cooling water passage 6 upstream of the thermovalve 9 to detect the cooling water temperature, thermovalve 9, 10
A signal SWI from a first water temperature switch 52 that outputs an on signal when the water temperature of the downstream first cooling water passage 6 reaches a set temperature is input.

Further, a second water temperature switch 53 that operates at a degree higher than the operating set temperature of the first water temperature switch 52 is installed in parallel with the first water temperature switch 52, and a second electric fan is operated based on a signal from the second water temperature switch 53. 46 drives are performed. The first water temperature switch 52 is turned ON at a first temperature (approximately 97°C) that is higher than the opening temperature (97°C) of the high temperature thermovalve 9, and the second water temperature switch 53 is turned ON at a second temperature higher than this (97°C). It is set to turn on at a temperature of 108 degrees Celsius (for example, 108 degrees Celsius).

The controller 50 receives signals from each of the sensors and switches, updates and stores this when the detected outside temperature Ta falls below the previous maximum outside temperature Taiin, and
It is determined whether the lowest outside temperature Tamln is equal to or higher than a set value for heater use (for example, 15° C.), and when the outside temperature is low, the actuator 35 is inactive and the first on-off valve 34 is in the open state, that is, the valve opening temperature on the low temperature side. It is controlled so that it is maintained at .

Also, if the minimum outside temperature Tasln is higher than the set value, the engine
is in a low load state, the three-way solenoid valve 40
The first on-off valve 34 is closed by applying negative intake pressure to the actuator 35.

Also, turn on the first water temperature switch 52 (1f to No. 2).
℃ or higher, if the first on-off valve 34 is open, the rotation of the first electric fan 745 is started, and when the first on-off valve 34 is closed, the drive is stopped. . on the other hand,
If the first on-off valve 34 is in the closed state at a temperature of 108° C. or higher based on the detection by the water temperature sensor 51, the three-way solenoid valve 40 is opened (opened to the atmosphere) to open the first on-off valve 34.
The actuator 35 is actuated to open the door 4.

The processing of the controller 50 that performs the above control is performed in a third manner.
This will be explained along the flowchart in the figure.

First, after starting the control, in step S1 the maximum ff (outside air m
After setting TaIIin to the initial light value (20°C), in step S2, the outside air WTa, water temperature Tw, and engine revolution number N are set.
e, fuel injection pulse Ps, and first water temperature switch SWI signals are read.

Then, in step S3, the detected outside temperature Ta is the lowest outside temperature T
It is determined whether or not the temperature is lower than awin, and if the determination is YES, the value of the minimum outside temperature Tasln is updated by the detected outside temperature Ta, and the minimum outside temperature T is sequentially updated.
Remember amin.

Next, in steps S5 to S8, the driving conditions of the actuator 35 are determined. First, in step S5, the water temperature Tw is IO
Determine whether the water temperature is 8℃ or higher, and if the determination is YES, the water temperature is l
If the temperature is 08℃ or higher, step SIO
Then, the three-way solenoid valve 40 is slightly opened, atmospheric pressure is introduced into the actuator 35, and the first on-off valve 34 is opened.

On the other hand, water 4! If Tw is 108°C or less, it is determined in step S6 whether the minimum outside temperature Tamln is 15°C or more, and in step S7 the engine revolution number N is determined.
In step S8, it is determined whether e is in a quadratic rotation state where e is 250 (lrpm or less) and whether or not the fuel injection pulse Ps is in a low load state where it is 5.15 mmsec or less. If any of the determinations is No, the above Proceeding to step S10, the first on-off valve 34 is opened.

In a high rotation range where the engine rotation speed Ne is 2500 rpm or more, the first on-off valve 34 is not closed because the engine generates a large amount of heat and gives priority to cooling performance.

Then, the fuel injection 1.1 pulse Ps is 5. I5IIlls
Low negative 6 below ec: In state j, the lowest outside temperature T a
When min is 15℃ or higher and engine speed Ne is 25
00 rpm or less, the process advances to step S9, where the three-way solenoid valve 40 is operated to close the actuator 3.
5, the first on-off valve 34 is closed,
Start water temperature increase control to increase combustion efficiency.

As a result, the opening operation of the low-temperature thermovalve 10 is disabled, the cooling water is not circulated to the radiator 4 until the high-temperature thermovalve 9 is opened, and the temperature of the water jacket 2 of the engine body 1 is increased.

Next, in steps Sll and Sl2, the first electric fan 4
Determine the driving conditions of No. 5. In step Sl1, it is determined whether water temperature increase control in which the three-way solenoid valve 40, that is, the first on-off valve 34 is closed, is being executed, and in step Sl2, the signal SWl of the first water temperature switch 52 is in the ON state, that is, the water temperature is Determine whether the temperature is 97°C or higher. Then, when the first on-off valve 34 is open and the water temperature is 97°C or higher, the first electric fan 745 is driven in step SI3, and the first on-off valve 34 is closed and the water temperature is 97°C.
In the following conditions, the process advances to step 514 and the first electric valve 7
The engine 45 is not driven.

FIG. 4 shows an example of a modified structure of an actuator 35' that opens and closes the first on-off valve 34. As shown in FIG.

A negative pressure chamber 57 is formed in the case 55 by a diaphragm 56, and the base end of the rod 58 is attached to the diaphragm 56.
i! i1, and the first on-off valve 34 is attached to the tip of this rod 58.
is installed. Five springs that bias the first on-off valve 34 in the closing direction are compressed in the negative pressure chamber 57, and the negative pressure introducing passage 38 is connected to the negative pressure chamber 57. A double sealing member 6-1, 62 is provided on the outer periphery of the rod 58 to prevent cooling water from entering the negative pressure chamber 57, thereby improving sealing performance. Note that if cooling water enters the negative pressure chamber 57, it will be sucked into the engine E from the intake passage through the negative pressure introduction passage 38, causing a serious problem, so the above-mentioned double seal structure is adopted.

Furthermore, when the ml seal member 61 is damaged and water intrudes into the second seal member 62, the structure is such that water is jetted out from the water hole 63 to warn of the damage. Further, when the amount of cooling water is reduced due to this jetting of cooling water, the level sensor displays the amount of the amount of the cooling water. Further, instead of installing the water hole 63, a water sensor is provided between the first seal member 61 and the second seal member 62,
An alarm may be displayed to indicate that cooling water has entered this area.

The operation of the above embodiment will be explained with reference to FIG.
-IE shows the operational change with respect to temperature change in a low load state, and IIA to IIE show the operational change with respect to temperature change in a high negative direction state.

First, in the high load, high rotation, or low outer 27u state (2), the first on-off valve 34 is opened by the operation of the actuator 35. In this state, if the water temperature is below 82℃ (IIA), the low and high temperature thermoharves 10,9
Both are closed and cooling water is circulated through the large and small bypass passages 25, and in this state, the electric fan 45 is OFF. When the water temperature exceeds 82°C, the valve body 10a of the low-temperature thermovalve 10 begins to open, while both bypass passages 25 are open and a portion of the cooling water flows toward the radiator 4 (I
IB).

When the water temperature further rises to about 97°C (■C), the large diameter bypass passage 25b is closed by the third rA closing valve 10b of the low temperature thermovalve 10, while the high temperature thermovalve 9
The valve body 9a begins to open, and the amount of cooling water flowing to the radiator 4 side increases. Further, the driving of the first electric fan 745 is started, and the amount of heat dissipated from the radiator 4 increases. The water temperature further rises to 1 (range CUD from 15℃ to IO8℃)? :4
:i, the second on-off valve 9b of the high-temperature thermovalve 9 closes the small-diameter bypass passage 25a, and the entire amount of cooling water flows into the radiator 4. When the temperature reaches 108℃ or higher (IIE), the second
The driving of the electric fan 46 is also started, and cooling is performed using the maximum cooling capacity.

On the other hand, in the low load, low rotation, and low outside temperature state I, the first on-off valve 34 is closed in a region where the water temperature is below IH°C. In this state, the water temperature is below 82℃ (I
In A), the high load ■,! Similarly to 7, both the low temperature and high temperature thermo valves 10 and 9 are closed, and cooling water is circulated through the large and small bypass passages 25, and in this state, the electric fan 45 is OFF. When the water temperature exceeds 82°C, the valve body 10a of the low-temperature thermovalve 10 starts to open, but the first on-off valve 34 closes, so the cooling water does not flow to the radiator 4, and the both bypass passages 25 that are open allow the cooling water to flow. It circulates within the engine body 1 (IB).

When the water temperature further rises to about 97°C (IC), the large-diameter bypass passage 25b is closed by the third on-off valve 10b of the low-temperature thermovalve 10, while the valve body 9a of the high-temperature thermovalve 9 begins to open, and the radiator 4 side The cooling water begins to flow, and the cooling water temperature reaches 97°C by the closing operation of the first on-off valve 34.
The temperature is maintained at a higher temperature than above, and fuel efficiency is improved by improving combustion efficiency. Further, the first electric fan 45 is maintained in a stopped state.

When the water temperature rises to 105°C to 108°C (ID), the second on-off valve 9b of the high temperature thermovalve 9
5a is closed and the entire amount of cooling water flows to the radiator 4 via the high temperature thermo valve 9. Even in this state, the first electric fan 45 is kept in a stopped state, and the temperature of the cooling water flowing into the engine body 1 is prevented from rapidly decreasing due to an increase in the amount of heat dissipated by the radiator 4 due to the operation of the electric fan 745. This is done to maintain combustion efficiency. When the water temperature reaches 108° C. or higher (IE), the first on-off valve 34 is opened, and the first and second electric fans 45.4
6 is also started, and the temperature rise is suppressed.

As mentioned above, under high load conditions, the cooling performance is gradually increased from 82°C by opening and closing the low-temperature thermovalve 10, and the cooling performance is gradually increased from 82°C to 97°C.
The operation of the electric fan 45 is started from ℃ to maintain an appropriate temperature state, while in the low negative -:f state, the first on-off valve 34 qualitatively disables the operation of the low-temperature thermovalve 10 and opens and closes the high-temperature thermovalve 9. Through operation, the cooling performance is increased from 97°C to maintain the high temperature state, and the vibration of the electric fan 45 is stopped to maintain the high temperature up to 108°C. I am trying to avoid this and improve fuel efficiency.

Also, due to the configuration of large and small bypass passages that are opened and closed by the low-temperature and high-temperature thermovalve 10, 9, the first on-off valve 34 is closed in a low load state, and the large-diameter bypass passage 25b is closed by the third on-off valve 10b of the low-temperature thermovalve 10. When the engine suddenly shifts to high-load operation from a closed state where cooling water is being circulated through the small-diameter bypass passage 25a, the first on-off valve 34 will open. Since the bypass passage 25a has a small diameter, most of the cooling water passes through the low-temperature thermovalve 10 and flows into the first cooling water passage 7i! It is sent from the i6 to the radiator 4, improving its cooling capacity and being able to respond to high load conditions.

The lowest outside air temperature mTamin in the above embodiment is the lowest intake air temperature detected from the start of operation, and even if the ambient temperature of the engine E increases, it shows a temperature close to the actual outside air temperature, and this lowest outside air temperature Tati1n Since the heater is used when the outside temperature is low, below 15 degrees Celsius, the actuator 35 is used to prevent large changes in the cooling water temperature.
is in a non-operating state so that the first on-off valve 34 does not close.

Further, according to the embodiment, when the heater is used according to the outside temperature and the change in the heating temperature is suppressed between 0 and +7, and when the cooling water temperature is increased by changing the actuator 35, By restricting the rotation of the electric fan 45 installed in the radiator 4 even at its rotation start temperature, the amount of heat dissipated due to the rotation of the electric fan 45 when the cooling water temperature increases is reduced. This prevents the cooling water temperature from decreasing rapidly due to a sudden drop in the cooling water temperature, thereby ensuring the high temperature effect, and further reducing engine negative C due to unnecessary driving of the electric fan 45.
It is possible to prevent an increase in I and further improve fuel efficiency. Furthermore, when the cooling water temperature rises, the actuator 35 is operated to the low temperature side, thereby increasing the amount of cooling water circulating to the radiator 4 to lower the temperature and improve reliability. can be secured.

In the above embodiment, the first on-off valve 34, the low-temperature thermovalve 10, and the high-temperature thermovalve 9 are configured separately, but the supporting positions of the two wax pellets are changed to allow one
A mechanism may be adopted in which one thermovalve is used and its opening temperature is nl<. In addition to the wax type thermovalve, a bellows type thermovalve may also be used. Furthermore, the actuator 35 for opening and closing the first on-off valve 34 may be composed of an electromagnetic plunger or the like instead of the diaphragm type. You may also do so. Furthermore, since the second and third on-off valves 9b and 10b can be opened and closed in conjunction with the operation of the thermovalve 9 and 10, the way in which they are mounted can be changed as appropriate depending on the type of thermovalve.

In addition, the outside air temperature is detected by the intake air amount sensor in the intake passage, which is used to control the engine air-fuel ratio.In addition, a separate temperature sensor is placed in a part that is not easily affected by the engine temperature to detect the outside air temperature. Detection may be performed by snooping.

Furthermore, in the above embodiment, when the first on-off valve 34 is closed under low load, when the water temperature reaches 108° C., the actuator 35 is actuated to open the first on-off valve 34, and at the same time, the electric fan 45 and 46, however, simply opening the first on-off valve 34 to increase the amount of flow to the radiator 4 can improve cooling performance and ensure reliability. Furthermore, in the above example, the opening temperature of the high-temperature thermovalve 9 and the drive start temperature of the lm-th electric fan 45 are set to the same temperature (97°C), but the drive start temperature of the first electric fan 45 is The temperature is set to be higher than the opening temperature of the kagome thermovalve 9. First, the engine body 1 is not intended to be a rotary piston engine.

(Effects of the Invention) According to the present invention as described above, the substantial valve opening temperature of the thermovalp, which is equipped with a heater passage that bypasses the radiator and has a plurality of different valve opening constant temperatures of 6°, can be changed by an actuator. By controlling the temperature of the cooling water that circulates through the engine at a high level during low-load conditions, it is possible to improve fuel efficiency by increasing the temperature of the cooling water that circulates through the engine and improving combustion efficiency. It is possible to improve cooling performance and maintain engine temperature within a predetermined range to ensure reliability.

Also, the lowest detected outside temperature is maintained from the start of operation. '
7L, the lowest outside temperature is below the predetermined value, 11,!
At f, the operation of the actuator is stopped and the temperature setting for opening the thermovalve is changed to f'>J}-, so that the outside air is low. Since there is a possibility that the heater will be used, the actuator will not be operated even if the load condition is high, and the large fluctuation in the cooling water temperature caused by the valve opening temperature will be suppressed. By accurately determining whether the outside temperature is low, it is possible to ensure fuel efficiency while suppressing fluctuations in heating temperature.

4. R+T+QT explanation of the drawings FIG. 1 is a schematic configuration diagram of an engine cooling system showing the basic configuration of the present invention, FIG. 2 is an overall configuration diagram of an engine cooling system showing a specific example, and FIG. FIG. 4 is a sectional view showing a specific example of the actuator, and FIG. 5 is an explanatory view showing a negative Gj state and an operating state in which temperature changes by χ·1.

E...Engine, A...Negative Q detection means, B...Outside temperature detection T stage, C...Actuator control T stage, D... Outside temperature input stage R, F...
...Regulation stage, TV...Thermo valve, 1
... Engine body, 2 ... Water jacket, 4 ... Radiator, 6.13 ...
...Cooling water passage, 14...Water bomb, 7,
8... Open passage, 9... High temperature thermo valve, 10... Low temperature thermo valve, 25...
...Bypass passage, 34...First on-off valve, 3
5. 35'...actuator, 40...
... Three-way solenoid valve, 47 ... Heater passage, 48 ... Heat exchange section, 50 ... Controller, 51 ... Water temperature sensor, 52 ...
...Watermelon switch.

Claims (1)

[Claims] (1) A cooling water passage that circulates cooling water from the engine water jacket to an external radiator has a heater passage that is equipped with a heat exchange section and is arranged to bypass the radiator, and has a plurality of different valve opening temperature settings. A thermovalve, an actuator that operates to substantially change the valve opening temperature of the thermovalve to a high temperature side, and actuator control means that changes the actuator to a high temperature side in a low load state depending on the load condition of the engine. In an engine cooling system, an outside temperature detection means detects outside temperature from intake air temperature, etc., an outside temperature input means receives a signal from the outside temperature detection means, and detects and holds the lowest outside temperature since the start of operation, and the above-mentioned 1. A cooling device for an engine, comprising: a regulating means that receives a signal from an outside temperature input means and stops the operation of the actuator when the lowest outside temperature is lower than a predetermined value.