JPH10317967A - Cooling control device for internal combustion engine - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a cooling control device that can always control the temperature of an engine to an optimal operating state, prevent occurrence of overheating of the engine, and exhibit a fail-safe function. To provide. A control valve unit is arranged in a cooling water circulation path between an engine and a radiator. In the control valve unit 11, a thermostat-type control valve 21 and an electromagnetic control valve 22 are respectively arranged in parallel, and both are configured to control the flow rate of cooling water. The electromagnetic control valve 22 is configured to be controlled by a control unit (ECU) that manages the operating state of the engine. With this configuration, it is possible to obtain a flow control that makes use of the characteristics of the two control valves 21 and 22. Ideal temperature control of the cooling water can be realized. Further, even if a failure occurs in one of the control valves, it is possible to prevent the engine from overheating.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling control device for cooling an internal combustion engine such as an engine for an automobile,
In particular, the present invention relates to a cooling control device for an internal combustion engine that can always maintain an engine temperature in an optimum operating state.

[0002]

2. Description of the Related Art In an internal combustion engine (hereinafter referred to as an engine) used for an automobile or the like, a water-cooled cooling device using a radiator is generally used for cooling the engine. In this type of cooling device, a thermostat is used to control the temperature of the cooling water, and when the cooling water is lower than a predetermined temperature, the cooling water flows to a bypass passage by the action of the thermostat. The cooling water is circulated without passing through the radiator. FIG.
The reference numeral 1 denotes an internal combustion engine composed of a cylinder block 1a and a cylinder head 1b. The cylinder block 1a of the engine 1
Further, a fluid passage indicated by an arrow c is formed in the cylinder head 1b. Reference numeral 2 denotes a heat exchanger, that is, a radiator. The radiator 2 has a fluid passage 2c as is well known, and a cooling water inlet 2a and a cooling water outlet 2b of the radiator 2 Is connected to a cooling water passage 3 for circulating cooling water.

The cooling water passage 3 has an outlet cooling water passage 3a communicating from a cooling water outflow portion 1d provided in the upper part of the engine 1 to a cooling water inflow portion 2a provided in the upper part of the radiator 2, and a cooling water passage 3a of the radiator 2. An inflow cooling water passage 3b communicating from a cooling water outflow portion 2b provided at a lower portion to a cooling water inflow portion 1e provided at a lower portion of the engine 1, and a bypass water passage connecting midway portions of the two cooling water passages 3a, 3b. 3c. Further, a thermostat 4 is disposed at a branch portion of the cooling water channel 3 between the outflow-side cooling water channel 3a and the bypass water channel 3c. The thermostat 4 has a built-in thermal expansion body (for example, wax) that expands and contracts due to a change in cooling water temperature, and when the cooling water temperature is high (for example, 80 ° C. or higher), the thermal expansion body expands. The valve is opened to allow the cooling water flowing out of the outflow portion 1d of the engine 1 to flow into the radiator 2 through the outflow-side cooling water passage 3a, and the cooling water that has been radiated by the radiator 2 and has a low temperature flows out of the outflow portion 2b. Cooling water passage 3b
Through the inflow portion 1e of the engine 1 so as to flow into the engine 1.

When the temperature of the cooling water is low, the valve of the thermostat 4 is closed by the contraction of the thermal expansion member, and the cooling water flowing out of the outlet 1d of the engine 1 is supplied to the bypass water passage 3d.
c, it flows from the inflow portion 1e of the engine 1 to the cooling passage c in the engine 1. Note that FIG.
In the figure, reference numeral 5 denotes a water pump disposed in the inflow portion 1e of the engine 1, which rotates a rotation shaft by rotation of a crankshaft (not shown) of the engine 1 to forcibly circulate cooling water. Reference numeral 6 denotes a fan unit for forcing cooling air into the radiator 2 and includes a cooling fan 6a and a fan motor 6b for rotating the fan.

[0005]

By the way, the valve opening and valve closing action by the thermostat as described above is determined by the temperature of the cooling water, and moreover by the expansion and contraction action by a thermal expansion body such as wax. It is. The thermal expansion body, such as the wax, requires a certain period of time from the time when the temperature of the cooling water changes to the time when the valve operates due to expansion and contraction. And the so-called hysteresis characteristics are large. For this reason, there is a technical problem that it is extremely difficult to adjust the cooling water to a desired constant temperature.

In addition, in the above-described thermostat, since the lift amount of the wax element is physically constant, the valve opening and closing operations are performed unless a certain degree of temperature change (temperature rise or temperature decrease) occurs. Does not occur, and it is impossible to perform minute temperature control on the cooling water. In addition, since the thermostat as described above is disposed in the circulation path of the cooling water and operates only by the temperature of the cooling water, rapid cooling control corresponding to the load of the engine cannot be expected. Further, the thermostat is always exposed to a high temperature during operation of the engine, so that any failure due to deterioration or the like occurs, but it cannot be corrected. Therefore, accurate engine temperature control cannot be performed, and technical problems such as overheating and overcooling of the engine remain.

The present invention has been made to solve the above-mentioned technical problems, and an object thereof is to provide a cooling control device capable of always controlling the temperature of an engine to an optimum operating state. is there. Another object of the present invention is to provide a cooling control device capable of preventing a problem such as causing the engine to overheat due to a failure of a part of the control valve and exhibiting a fail-safe function. In addition, an object of the present invention is to provide a cooling control device which can easily carry out maintenance of an opening / closing valve portion for controlling a flow rate of a cooling medium, in which a failure is relatively likely to occur. Another object of the present invention is to provide a cooling control device that can be a small and inexpensive electromagnetic control valve by using the electromagnetic control valve as a complement to a thermostatic control valve.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a cooling control apparatus for an internal combustion engine according to the present invention comprises a fluid passage formed in an internal combustion engine and a fluid passage formed in a heat exchanger. A cooling control device for an internal combustion engine, wherein a cooling medium circulation path is formed between the cooling medium and the heat generated in the internal combustion engine by circulating the cooling medium through the circulation path to be radiated by the heat exchanger. A plurality of control valves for controlling the flow rate of the cooling medium circulating between the internal combustion engine and the heat exchanger are arranged in parallel. With such a configuration, the cooling control device independently controls the circulation of the cooling medium by the respective control valves arranged in parallel. Even if one of the control valves fails, the cooling control is performed by the other control valve. Demonstrate possible fail-safe function.

In this case, one of the control valves uses a thermostatic control valve that changes its shape depending on the temperature of the cooling medium and controls the flow rate of the cooling medium, and the other one of the control valves has a different shape.
First, it is desirable to use an electromagnetic control valve that controls the flow rate of the cooling medium by operating the electromagnetic actuator. According to such a configuration, the thermostatic control valve functions as a main control valve, and the electromagnetic control valve functions as a sub control valve. The slow opening / closing action of the main control valve is complemented by the sub-control valve, so that the temperature of the engine can always be controlled to an optimal operating state. In addition, a plurality of control valves arranged in parallel include one control valve.
Preferably, it is housed in two housings, said housings being arranged in the circulation of the cooling medium between the internal combustion engine and the heat exchanger. With this configuration, it is possible to remove the entire housing when one of the control valves fails or the like, so that the maintenance can be easily performed and the vehicle can be easily mounted on the outboard equipment.

In a preferred embodiment, the thermostatic control valve contains a wax that expands or contracts depending on the temperature of a cooling medium, and is opened or closed according to a change in the volume of the wax. It is configured to be. As a result, valve opening and valve closing actions against the flow pressure of the cooling medium can be reliably obtained, and the reliability of the thermostatic control valve using wax can be ensured by utilizing the characteristics of the thermostatic control valve. Further, in a preferred embodiment, a control unit that generates a control signal in accordance with a detection signal from at least one detection sensor that detects an operation state of the internal combustion engine is provided, and a control signal from the control unit includes: It is configured to control the electromagnetic actuator. Therefore, it is possible to more precisely and quickly control the temperature of the internal combustion engine by the electronic action. In this case, the detection sensor is arranged in the circulation path of the cooling medium of the internal combustion engine, and is configured to detect the temperature of the cooling medium in the circulation path, so that the accuracy of temperature management can be improved. Become.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a cooling control device for an internal combustion engine according to the present invention will be described based on an embodiment shown in the drawings. FIG. 1 shows an entire configuration applied to a cooling control device for an automobile engine. In FIG. 1, the same reference numerals as those in the conventional apparatus shown in FIG. 3 indicate corresponding parts, and therefore, the description of the individual configurations and operations will be omitted as appropriate. As shown in FIG. 1, the cooling water is provided between an outflow portion 1 d of cooling water provided at an upper portion of an engine 1 as an internal combustion engine and an inflow portion 2 a of cooling water provided at an upper portion of a radiator 2 as a heat exchanger. The control valve unit 11 is connected to the outlet-side cooling water channel 3a.
As a result, a cooling medium, that is, a cooling water circulation path 12 is formed so as to include the control valve unit 11. Further, the outflow portion 1d of the cooling water in the engine 1 includes:
For example, a temperature detecting element 13 such as a thermistor is arranged. The value detected by the temperature detection element 13 is
The data is converted into data recognizable by the control unit (ECU) 15 and supplied to the control unit (ECU) 15 for controlling the operating state of the entire engine.

Further, in the embodiment shown in FIG.
Data from a throttle position sensor 17 for detecting the opening of the throttle valve 16 of the engine 1 is also supplied to the control unit 15. Although not shown, the control unit 15 is also configured to be supplied with information such as the number of revolutions of the engine. On the other hand, a control signal is supplied from the control unit 15 to the current control circuit 18. The current control circuit 18 is configured so that the current supplied from the battery 19 is supplied from the control unit 15 to an electromagnetic actuator described later in the control valve unit 11 according to a control signal.

FIG. 2 shows the configuration of the control valve unit 11 in a sectional state. This control valve unit 11
Have connection flanges 11a, 11b
Are formed to form a housing, and are connected to an intermediate portion of the cooling water passage 3a through the flanges 11a and 11b. In the control valve unit 11, control valves for independently controlling the flow rate of cooling water as a cooling medium via a central partition wall 11c are arranged in parallel. One of the control valves is a thermostat-type control valve 21 that changes its shape depending on the temperature of the cooling water and controls the flow rate of the cooling water, and the other one of the control valves cools by operating an electromagnetic actuator. An electromagnetic control valve 22 for controlling the flow rate of water.

The thermostatic control valve 21 includes a frame 21a, a flange 21c attached to the frame 21a and supporting a thermo-element 21b as a temperature-sensitive operating body, and a valve 21d opened and closed by the thermo-element 21b. And a spring 21e for urging the valve body 21d in a direction to always close the valve body. The thermoelement 21b further advances and retreats while being guided by the piston guide 21f, and has a front end at the flange portion 2.
A piston 21h engaged with the top of the supporting portion 21g formed in 1c, a temperature sensing portion 21j including a wax 21i as a thermal expansion body that expands or contracts due to a temperature change of the cooling water and moves the piston 21h forward and backward. It is composed of The flange portion 21c is attached to a housing constituting the outer shell of the control valve unit 11.

Therefore, the cooling water flowing into the control valve unit 11 is at a predetermined temperature or higher (for example, at 80 ° C. or higher).
Then, the wax 2 built in the temperature sensing unit 21j
1i expands, and the piston 21h projects toward the top of the support 21g formed on the frame 21a. For this reason,
The reaction causes the valve body 21d to open and acts to allow cooling water to pass. Further, when the heat radiation of the cooling water is promoted and the cooling water flowing into the control valve unit 11 becomes a predetermined temperature or lower (for example, 80 ° C. or lower), the temperature sensor 21
The wax 21i contained in j is shrunk, and the valve body 21d is closed by the action opposite to the above, and acts to prevent the passage of cooling water.

On the other hand, the electromagnetic control valve 22 also controls the control valve unit 1.
1 housing. This control valve 22
Is composed of a circular opening 11d formed in the central partition wall 11c in the housing of the control valve unit 11 and communicating the inflow side and the outflow side of the cooling water, and a poppet valve 22a for closing and opening this opening 11d. Have been. The poppet valve 22a penetrates a housing side wall of the control valve unit 11, and is attached to an end of a rod 22b held by a seal portion 11e so as to be able to reciprocate in the axial direction. The other end of the rod 22b outside the side wall of the housing is provided with a cylindrical magnetic body 22c as a mover.
Is fitted, and an electromagnetic coil 22d is arranged so as to surround the magnetic body 22c. This magnetic body 22
c and an electromagnetic coil 22d constitute an electromagnetic actuator, and the electromagnetic coil 22d is attached to the housing by a casing 22e attached to the side wall of the housing.

A coil-shaped expanding spring 2 is provided in a space between the cylindrical magnetic body 22c and the casing 22e.
2f is disposed, and is urged by the spring 22f in a direction to close the opening 11d by the poppet valve 22a. The control current is supplied from the current control circuit 18 to the electromagnetic coil 22d as shown in FIG. 1, so that the poppet valve 22a moves in the direction AA 'in FIG. 2 according to the amount of the control current. Moved to Thus, the flow rate of the cooling water is controlled by the electromagnetic control valve 22.

When the engine 1 is operated in the above configuration, the water pump 5 is driven, and as a result, the cooling water sealed in the circulation path 12 is circulated. Engine 1
In the normal temperature state of the engine immediately after the start of the operation, the thermostatic control valve 21 and the electromagnetic control valve 22 arranged in the control valve unit 11 are both closed. As a result, the cooling water sealed in the circulation passage 12 is circulated between the cooling water and the fluid passage c in the engine 1 via the bypass passage 3c. Here, as described above, the thermostat-type control valve 21 in the control valve unit 11 has a slow opening and closing action on the cooling water temperature. on the other hand,
The control unit 15 is supplied with temperature information from the temperature detecting element 13 disposed at the outflow portion 1 d of the cooling water in the engine 1.

Therefore, prior to the valve opening operation of the thermostatic control valve 21 based on the temperature rise of the cooling water, the electromagnetic control valve 22 is opened, and the cooling water flows to the radiator 2 side. Then, when the temperature of the cooling water is sufficiently increased, the thermostat-type control valve 21 is opened, and the cooling water flows to the radiator 2 via the two. In this way, the heat radiation by the radiator 2 is promoted, and when the cooling water temperature decreases, prior to the closing action of the thermostat-type control valve 21,
Based on the temperature information from the temperature detecting element 13, the electromagnetic control valve 22
Is closed to reduce the amount of cooling water flowing to the radiator 2 side. Accordingly, the temperature of the cooling water is prevented from being excessively lowered, and the hysteresis characteristic of the on-off valve operation with respect to the temperature of the thermostatic control valve 21 is complemented by the operation of the electromagnetic control valve 22.

As a result, the operation of the engine 1 is performed within a predetermined temperature range. For example, when the temperature is controlled only by the thermostatic control valve 21, the delay of the opening / closing operation of the engine 1 causes the ideal engine temperature to be reduced. As a result, the occurrence of a so-called hunting phenomenon in which the cooling water temperature moves up and down can be suppressed. The control unit 15 is also supplied with information on the opening degree of the throttle valve 16 and information on the number of revolutions of the engine from the throttle position sensor 17, and therefore, by utilizing these information other than the cooling water temperature, By predicting the vertical movement of the water temperature, it is possible to control the temperature of the cooling water, that is, to ideally control the temperature of the combustion chamber of the engine.

According to the present invention, in addition to the above-described special effects provided by the provision of the thermostatic control valve and the electromagnetic control valve as described above, even if a failure occurs in either the thermostatic control valve or the electromagnetic control valve. However, since the flow of the cooling water can be controlled independently of each other, it is possible to prevent the occurrence of overheating of the engine, etc., and to exhibit the fail-safe function. In the above-described embodiment, a linear electromagnetic actuator that controls the valve opening amount in accordance with the amount of current supplied from the current control circuit 18 is used. The valve opening time may be controlled in place of the plunger type solenoid that takes two states.

In the above-described embodiment, a thermostat-type control valve having a built-in wax is used. Alternatively, for example, a bimetal or a bellows operated by changing the internal pressure depending on the temperature may be used. Type thermostats can also be used. Also,
The cooling control device for an automobile engine has been described as an example, but the present invention is not limited to such a specific one, and similar effects can be obtained by applying the present invention to other internal combustion engines.

[0023]

As described above, according to the cooling control apparatus for an internal combustion engine according to the present invention, for example, a thermostat-type control valve and an electromagnetic valve are provided in a circulation path of a cooling medium formed between the internal combustion engine and the heat exchanger. By arranging the control valve and the control valve in parallel and controlling the flow rate of the cooling medium by these, it is possible to obtain flow rate control that makes use of the characteristics of both, and realize ideal temperature management of the cooling medium Can be done. Further, even if a failure occurs in any one of the control valves, it is possible to prevent occurrence of overheating of the engine and the like, and to exhibit a fail-safe function. Further, in the present invention, since the electromagnetic control valve is used as a complement to the thermostat type control valve, it is not necessary to prepare an electromagnetic actuator having a particularly strong driving force, thereby providing a small and inexpensive electromagnetic control valve. The used flow control unit can be used.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an embodiment of a cooling control device for an internal combustion engine according to the present invention.

FIG. 2 is a sectional view showing a configuration of a control valve unit in the device shown in FIG.

FIG. 3 is a configuration diagram illustrating an example of a conventional cooling control device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Internal-combustion engine (engine) 2 Heat exchanger (radiator) 2c Fluid path 3 Cooling water channel 5 Water pump 6 Fan unit 6a Cooling fan 6b Fan motor 11 Control valve unit (housing) 12 Cooling medium circulation path 13 Temperature detection element 15 Control unit ( ECU) 16 Throttle valve 17 Throttle position sensor 18 Current control circuit 19 Battery 21 Thermostat type control valve 22 Electromagnetic control valve 22c Magnetic body (electromagnetic actuator) 22d Electromagnetic coil (electromagnetic actuator) c Fluid passage in internal combustion engine

Claims (6)

[Claims] 1. A cooling medium circulation path is formed between a fluid passage formed in an internal combustion engine and a fluid passage formed in a heat exchanger, and the cooling medium is circulated through the circulation path. A cooling control device for an internal combustion engine configured to radiate heat generated by the heat exchanger, wherein a plurality of control valves for controlling a flow rate of a cooling medium circulating between the internal combustion engine and the heat exchanger are provided. A cooling control device for an internal combustion engine, wherein the cooling control devices are arranged in parallel. 2. One of the control valves uses a thermostat-type control valve that changes its shape depending on the temperature of a cooling medium and controls a flow rate of the cooling medium. 2. The cooling control device for an internal combustion engine according to claim 1, wherein an electromagnetic control valve that controls the flow rate of the cooling medium by operating the actuator is used. 3. The plurality of control valves arranged in parallel are housed in one housing, and the housing is arranged in a circulation path of a cooling medium between an internal combustion engine and a heat exchanger. The cooling control device for an internal combustion engine according to claim 1 or 2, wherein: 4. The thermostatic control valve has a built-in wax that expands or contracts depending on the temperature of a cooling medium, and is configured to open or close according to a change in the volume of the wax. The cooling control device for an internal combustion engine according to claim 2 or 3, wherein 5. A control unit for generating a control signal according to a detection signal from at least one detection sensor for detecting an operation state of the internal combustion engine, wherein the electromagnetic actuator is controlled by the control signal from the control unit. 4. The cooling control device for an internal combustion engine according to claim 2, wherein the cooling control device is configured to perform control. 6. The sensor according to claim 5, wherein the detection sensor is disposed in a circulation path of a cooling medium of the internal combustion engine, and is configured to detect a temperature of the cooling medium in the circulation path. Internal combustion engine cooling control device.