JP2004132242A - Engine cooling water control valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an engine cooling water control valve of excellent response performance which can control the temperature of cooling water from the outside. <P>SOLUTION: The engine cooling water control valve comprises a main valve comprising a main valve seat 15 and a main valve element 16 disposed in a passage between an inlet 12 and an outlet 13, a diaphragm 22 to open/close the main valve element 16, a leak passage 26 to introduce the pressure on the upstream side of the main valve into a pressure chamber 38 demarcated by the diaphragm 22, and a pilot valve disposed between the pressure chamber 38 and the downstream side of the main valve and having a pilot valve seat 28 and a solenoid-driven pilot valve element 29 to control the opening by the control current from the outside. The lift of the main valve is determined by the pressure in the pressure chamber 38, and the pressure is determined by the opening of the pilot valve, i.e., the control current to the solenoid. Therefore, the main valve controls the flow rate so that the differential pressure before and behind the pilot valve is constant. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an engine coolant control valve, and more particularly to an engine coolant control valve provided in an engine coolant circulation system to control the engine coolant temperature.
[0002]
[Prior art]
In a water-cooled engine, a water jacket is formed in an engine body, connected to a radiator, and forced cooling water is circulated by an engine-driven pump. When the temperature of the cooling water is low, such as at the time of starting, the passage of the radiator is shut off, and the cooling water flowing out of the engine is returned to the engine as it is via a bypass passage that bypasses the radiator. A thermo valve using a wax thermostat is used as a temperature sensing part to open and close the passage of the radiator. (For example, see Patent Document 1).
[0003]
The wax thermostat valve senses the temperature of the cooling water by the wax thermostat, and mechanically opens and closes the thermo valve according to a change in the temperature of the cooling water. As a result, the cooling water temperature can be kept constant, so that the combustion efficiency and fuel efficiency of the engine can be improved.
[0004]
[Patent Document 1]
JP-A-11-173147 (FIGS. 1 and 8)
[0005]
[Problems to be solved by the invention]
However, in the wax thermostat valve, since the opening degree control is determined only by the cooling water temperature, there has been a problem that the cooling water temperature cannot be externally controlled according to the operating condition.
[0006]
In addition, the wax thermostat valve is a valve fail-safe mechanism, in the event that the valve falls into a state where it does not operate, the valve itself is destroyed and the cooling water is forced to flow through the radiator, returning to the normal operation state To do so, the bulb had to be replaced.
[0007]
Further, the wax thermostat valve controls the valve opening only by sensing the temperature of the wax thermoelement, and the wax thermoelement has poor response performance to temperature changes and takes a long time to operate. If the temperature at which the engine combustion efficiency is considered to be good is set at the upper limit of the control temperature range, it is not possible to cope with a sudden rise in cooling water temperature due to load operation, etc. However, since the water temperature rises to the temperature at which the engine overheats, the control temperature cannot be increased.
[0008]
The present invention has been made in view of such a point, and an object of the present invention is to provide an engine cooling water control valve having good responsiveness, which can control a cooling water temperature from the outside.
[0009]
[Means for Solving the Problems]
In the present invention, in order to solve the above problem, in an engine cooling water control valve for controlling the temperature of a cooling water of an engine, a main valve disposed in a passage between an inlet and an outlet of the cooling water; A diaphragm fixed to a valve body to open and close the main valve body and define a pressure chamber isolated from the inlet, and a leak path for introducing cooling water upstream of the main valve into the pressure chamber, A pilot valve disposed between the pressure chamber and a space downstream of the main valve, the opening of which is set by an externally controllable solenoid force to control the pressure of the pressure chamber. An engine cooling water control valve is provided.
[0010]
According to such an engine cooling water control valve, when cooling water is introduced from the radiator to the inlet, the diaphragm opens the main valve to flow the cooling water to the outlet. On the other hand, a part of the cooling water introduced into the inlet enters the pressure chamber partitioned by the diaphragm through the leak path, but when not energized, the pilot valve that is set to fully open moves the pressure chamber to the downstream side of the main valve. Since the communication is established, the main valve is maintained in the fully open state. At the time of energization, the opening of the pilot valve is set according to the value of the control current, and the pressure of the pressure chamber rises by restricting the cooling water flowing from the pressure chamber to the downstream side of the main valve, thereby increasing the diaphragm pressure. Drives the main valve body in the valve closing direction to control the flow rate of the cooling water flowing through the main valve. The opening of the main valve can be freely changed by an externally supplied control current, and can be changed almost instantaneously in response to a change in water temperature. There is no delay and the temperature is controlled to a predetermined value.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a system diagram showing a cooling water system of the engine.
[0012]
A cooling water system is a system that returns from a water jacket (not shown) formed in the main body of the engine 1 to one end via a radiator 2, an engine cooling water control valve 3, and an electric pump 4 to the water jacket in the engine 1. And a system for returning to the water jacket in the engine 1 via the heater core 5 and the pump 4 which are heat exchangers for heating. The cooling water system may be provided with a bypass passage 6 arranged to bypass the radiator 2 and the engine cooling water control valve 3 as necessary. The engine cooling water control valve 3 and the pump 4 are respectively controlled by a control device (not shown) based on a cooling water temperature detected by a water temperature sensor provided at a cooling water outlet of the engine 1, for example. Here, the pump 4 is controlled to be turned on and off, and circulates the cooling water at a constant rotation speed during operation.
[0013]
Here, when the temperature of the cooling water is still low, such as when starting the engine 1 which has been stopped for a while, the pump 4 is stopped and the engine cooling water control valve 3 is in a fully closed state. Thereby, the engine 1 is cooled by only a small amount of the cooling water in the water jacket, so that warm-up is promoted. When the cooling water in the water jacket reaches a predetermined temperature, the pump 4 is operated, the engine cooling water control valve 3 is fully closed, and the cooling water is circulated in the system of the heater core 5. Further, when the cooling water in the water jacket reaches the predetermined temperature again, the system of the radiator 2 circulates the cooling water by controlling the engine cooling water control valve 3 to an appropriate lift amount. Thereafter, by controlling the engine cooling water control valve 3 to an appropriate lift amount in accordance with the operating conditions and the like, optimal control of the cooling water temperature can be performed. Next, a specific configuration example of such an engine cooling water control valve 3 will be described.
[0014]
FIG. 2 is a central longitudinal sectional view showing the closed state of the engine cooling water control valve according to the first embodiment, and FIG. 3 is a central longitudinal view showing the valve opening state of the engine cooling water control valve according to the first embodiment. It is a longitudinal cross-sectional view.
[0015]
The engine cooling water control valve 3 has an inlet 12 formed on the side of the body 11 and communicating with the radiator 2, and an outlet 13 formed on the bottom of the body 11 and communicating with the pump 4. In the body 11, a tubular body 14 extending inward from the outlet 13 is formed integrally with the body 11, and the upper end of the tubular body 14 in the figure constitutes a main valve seat 15 of a main valve. are doing. A main valve body 16 is disposed opposite to the main valve seat 15 so as to be able to freely contact and separate from above in the figure. The main valve body 16 is held between a washer 17 and a guide 18, and is held by a holder 20 by a retaining ring 19. The guide 18 is integrally formed with three legs sliding along the inner wall of the tubular body 14, and moves in the axial direction while positioning the main valve body 16 and the holder 20 at the center of the tubular body 14. Guide you to move.
[0016]
The holder 20 is also fixed to the central part of the diaphragm 22. The diaphragm 22 has an outer peripheral edge sandwiched between the body 11 and the housing 21, has a larger pressure receiving area than the main valve body 16, and has a shape with a hole at the center. The center portion of the diaphragm 22 is sandwiched between two donut-shaped disks 23 and 24 from both sides, and the inner peripheral portions thereof are fixed to the holder 20 by caulking. Each of the two disks 23 and 24 has an annular groove formed so as to protrude in a direction away from the diaphragm 22, and forms a water path together with the diaphragm 22. The disk 24 facing the space communicating with the inlet 12 has a plurality of communication holes 25 formed in its annular groove. These communication holes 25 are for introducing cooling water into the pressure chamber 38 surrounded by the diaphragm 22 and the housing 21. By providing a plurality of the communication holes 25, the communication holes 25 also serve as a filter.
[0017]
The diaphragm 22 has one leak path 26 formed at a position where the annular grooves formed on the disks 23 and 24 are located, and one communication hole 27 also formed at the annular groove of the disk 23.
[0018]
The holder 20 has a passage communicating with the pressure chamber 38 and the outlet 13 at the center axis position, and a pilot valve seat 28 is integrally formed in the middle of the passage. A ball-shaped pilot valve body 29 is arranged to be able to advance and retreat from the outlet 13 side in opposition to the pilot valve seat 28, and constitutes a pilot valve that controls the pressure in the pressure chamber 38 together with the pilot valve seat 28. The valve hole of the pilot valve has a much larger cross-sectional area than the leak passage 26 formed in the diaphragm 22. The pilot valve element 29 is urged in a seating direction by a spring 30, and the spring 30 is received by an adjusting screw 31 screwed into a passage communicating between the pressure chamber 38 and the outlet 13. .
[0019]
A solenoid for setting the opening of the pilot valve is provided at the upper part of the holder 20 in the drawing. The solenoid includes a movable iron core 32 whose lower end is in contact with a pilot valve body 29, a fixed iron core 33 whose relative position with respect to the main valve body 16 does not change, a movable iron core 32 and a fixed iron core 33. Between the movable iron core 32 and the fixed iron core 33 according to the value of the supplied current. And an electromagnetic coil 35. Between the fixed iron core 33 and the holder 20, two shafts 36 inserted in grooves formed in the outer periphery of the movable iron core 32 in the axial direction are interposed, and a spring 37 holds the fixed iron core 33. The fixed iron core 33 is fixed to the holder 20 by being urged downward in the figure, but is movable in the axial direction with respect to the opening and closing operation of the main valve.
[0020]
In the engine cooling water control valve 3 having the above-described configuration, when the pump 4 is stopped and the control current is not supplied to the solenoid coil 35 of the solenoid, the movable iron core is moved to a position where the loads of the springs 30 and 34 are balanced. The pilot valve is fully opened by moving the valve body 32 and the pilot valve body 29. In addition, the main valve body 16 is seated on the main valve seat 15 by the spring 37 urging the holder 20 downward in the figure via the fixed iron core 33 and the shaft 36, and the main valve is as shown in FIG. As shown, it is in the fully closed state.
[0021]
Here, when cooling water is supplied from the radiator 2 to the inlet 12 of the engine cooling water control valve 3 by starting operation of the pump 4 while the solenoid is not energized, the urging force of the spring 37 is generated by the water pressure. The diaphragm 22 is displaced almost instantaneously upward in the figure against the pressure, and as shown in FIG. 3, the main valve body 16 is pushed up and the main valve is fully opened. At this time, since the amount of water flowing to the outlet 13 side via the pilot valve which is fully open is larger than the amount of water entering the pressure chamber 38 via the leak passage 26 of the diaphragm 22, the diaphragm 22 is Maintain a state displaced upward. That is, the engine cooling water control valve 3 has a normally open configuration in which the main valve is fully opened when the solenoid is not energized. At this time, the pressure difference between the pressure in the pressure chamber 38 and the pressure in the outlet 13 is the smallest.
[0022]
Next, when a predetermined control current is supplied to the electromagnetic coil 35 of the solenoid, the fixed iron core 33 attracts the movable iron core 32 against the urging force of the spring 34. As a result, the movable iron core 32 moves upward in the drawing, and accordingly, the pilot valve body 29 also moves upward, and the pilot valve is controlled in a direction to decrease its opening. As the opening of the pilot valve decreases, the amount of water flowing from the pressure chamber 38 to the downstream side of the main valve decreases, so that the pressure in the pressure chamber 38 increases, and the diaphragm 22 generates a difference between the pressure in the pressure chamber 38 and the pressure in the outlet 13. The main valve is displaced downward in the figure to a position corresponding to the pressure, and the main valve has a valve opening corresponding to the displacement of the diaphragm 22. Thereafter, the engine cooling water control valve 3 functions as an electromagnetic constant pressure differential valve that opens and closes the main valve so that the differential pressure across the pilot valve set by the solenoid is constant. Since the set differential pressure is substantially proportional to the control current whose value is determined by the operating condition including the cooling water temperature, the main valve can be linearly controlled from the outside. In addition, since the fixed iron core 33 of the solenoid that drives the pilot valve is moved in conjunction with the displacement of the diaphragm 22, the gap between the fixed iron core 33 and the movable iron core 32 is increased even when the diaphragm 22 is displaced. Since there is no change, the main valve whose main valve element makes a large stroke can be controlled with a small electromagnetic coil.
[0023]
FIG. 4 is a system diagram using the engine cooling water control valve according to the second embodiment, and FIG. 5 is a central longitudinal sectional view showing a closed state of the engine cooling water control valve according to the second embodiment. . In FIGS. 4 and 5, the same or equivalent components as those shown in FIGS. 1 to 3 are denoted by the same reference numerals.
[0024]
This system is characterized in that the engine cooling water control valve 3 used in the system of FIG. 1 operates only by the differential pressure before and after the engine cooling water control valve 3, whereas the system uses the pressure loss generated in the radiator 2 to operate. different.
[0025]
That is, the configuration of the engine cooling water control valve 3a having the main valve that is opened and closed by the diaphragm 22 between the inlet 12 and the outlet 13 is the same as that of the engine cooling water control valve 3 of the first embodiment. However, cooling water is introduced into the pressure chamber 38 from the upstream side of the radiator 2 via a pilot valve, and the cooling water is discharged from the pressure chamber 38 to the outlet 13 through the leak passage 26 formed in the diaphragm 22. Is configured. As a result, the diaphragm 22 is displaced by receiving a pressure loss generated when the cooling water passes through the radiator 2, and controls the opening of the main valve.
[0026]
As shown in detail in FIG. 5, the engine cooling water control valve 3a is provided on a main valve seat 15 formed between the inlet 12 and the outlet 13 so as to be able to freely contact and separate from the upstream side. The main valve body 16 is connected by a disk 40 to a diaphragm 22 provided to isolate a space communicating with the outlet 13 from the pressure chamber 38. The disk 40 is urged by a spring 41 in the valve closing direction of the main valve, and is provided with a leak path 26 that connects the outlet 13 and the pressure chamber 38.
[0027]
The pilot valve has an inlet 42 connected to the piping on the upstream side of the radiator 2 and an outlet 43 connected to the pressure chamber 38, and has a pilot valve body with respect to the pilot valve seat 28 formed therebetween. 29 is disposed so as to be able to freely contact and separate from the downstream side. The pilot valve element 29 is urged in a valve closing direction by a spring 34 disposed between a movable iron core 32 and a fixed iron core 33 of a solenoid.
[0028]
In the engine cooling water control valve 3a having the above configuration, when the electromagnetic coil 35 is not energized, the pilot valve is fully closed, and therefore, the pressure chamber 38 communicates with the low pressure side outlet 13 through the leak passage 26. Therefore, the diaphragm 22 is urged by the spring 41 so that the main valve body 16 is seated on the main valve seat 15 and is fully closed. Therefore, when the pump 4 is operated, the cooling water in the engine 1 circulates through the system of the heater core 5.
[0029]
When the electromagnetic coil 35 is energized, the movable iron core 32 is attracted to the fixed iron core 33, so that the high-pressure cooling water upstream of the radiator 2 pushes open the pilot valve body 29 and is introduced into the pressure chamber 38. You. As a result, the pressure in the pressure chamber 38 increases, so that the diaphragm 22 drives the main valve body 16 in the valve opening direction to open the main valve. The cooling water that has passed through the radiator 2 flows to the pump 4 via the opened main valve.
[0030]
When the control current supplied to the electromagnetic coil 35 is increased, the attraction force increases. Therefore, the pilot valve element 29 is further separated from the pilot valve seat 28 by the differential pressure between the pressure on the upstream side of the radiator 2 and the pressure in the pressure chamber 38. Thus, the opening of the pilot valve increases. As a result, the pressure in the pressure chamber 38 also increases, and the main valve body 16 is further separated from the main valve seat 15, so that the opening of the main valve can be increased.
[0031]
As described above, the main valve is provided on the downstream side of the radiator 2, and the differential pressure between the pressure on the upstream side of the radiator 2 and the pressure in the pressure chamber 38 is controlled by the pilot valve. The engine cooling water control valve according to the first embodiment, in which a large pressure loss inevitably generated by the flow of water can be used for the operation of the main valve, and the main valve is operated only by the pressure difference before and after the main valve. 3 can be operated more reliably.
[0032]
In the systems shown in FIGS. 1 and 4, an example in which the engine cooling water is circulated by an electric pump is shown. However, the present invention can be similarly applied to a system using an engine-driven internal pump.
[0033]
Further, in the second embodiment utilizing the pressure loss of the radiator, an example of the normally closed type in which the main valve is fully closed when the solenoid is not energized has been described. However, in the first embodiment, the diaphragm is used in the first embodiment. Is provided in the housing 21 or in a pipe connected to the housing 21, and the cooling water upstream of the radiator is introduced into the pressure chamber 38, thereby forming a normally open type engine cooling water control valve. be able to.
[0034]
【The invention's effect】
As described above, according to the present invention, the engine cooling water control valve is controlled by a pilot type electromagnetic valve in which the main valve is controlled by externally controlling the differential pressure between the inlet pressure and the pressure chamber by the pilot valve. It consisted of a constant differential pressure valve. As a result, the responsiveness is remarkably improved as compared with the wax thermostat valve, and the flow rate can be linearly controlled from the outside, so that the optimal cooling water temperature can be controlled according to the operating conditions and the like.
[0035]
By using a pilot-type electromagnetic constant differential pressure valve, a main valve element having a large pressure receiving diameter and a large lift amount can be controlled by a small electromagnetic coil, so that a small engine cooling water control valve can be configured.
[0036]
In the first embodiment, when the pump starts operating with the solenoid turned off, the main valve is automatically set to a fully open state so that a fail-safe mechanism can be ensured. Performance can be improved. By arranging the main valve, the diaphragm for operating the main valve, and the pilot valve coaxially, the engine cooling water control valve can be made smaller.
[0037]
In the second embodiment, the main valve can be reliably operated by employing a configuration in which the pressure loss inevitably generated in the radiator is used for the operation of the main valve.
[Brief description of the drawings]
FIG. 1 is a system diagram showing a cooling water system of an engine.
FIG. 2 is a central longitudinal sectional view showing a closed state of the engine cooling water control valve according to the first embodiment.
FIG. 3 is a central vertical sectional view showing an open state of the engine cooling water control valve according to the first embodiment.
FIG. 4 is a system diagram using an engine cooling water control valve according to a second embodiment.
FIG. 5 is a central longitudinal sectional view showing a closed state of an engine cooling water control valve according to a second embodiment.
[Explanation of symbols]
Reference Signs List 1 engine 2 radiator 3, 3a engine cooling water control valve 4 pump 5 heater core 6 bypass passage 11 body 12 inlet 13 outlet 14 cylindrical body 15 main valve seat 16 main valve body 17 washer 18 guide 19 retaining ring 20 holder 21 housing 22 diaphragm 23, 24 Disc 25 Communication hole 26 Leak path 27 Communication hole 28 Pilot valve seat 29 Pilot valve body 30 Spring 31 Adjust screw 32 Movable iron core 33 Fixed iron core 34 Spring 35 Electromagnetic coil 36 Shaft 37 Spring 38 Pressure chamber 40 Disk 41 Spring 42 entrance 43 exit

Claims (7)

In an engine cooling water control valve for controlling an engine cooling water temperature,
A main valve arranged in the passage between the inlet and outlet of the cooling water,
A diaphragm fixed to the main valve body of the main valve to open and close the main valve body and define a pressure chamber isolated from the inlet;
A leak path for introducing cooling water upstream of the main valve into the pressure chamber;
A pilot valve that is disposed between the pressure chamber and a space on the downstream side of the main valve, and whose opening is set by an externally controllable solenoid force to control the pressure of the pressure chamber,
An engine cooling water control valve, comprising: The engine cooling water control valve according to claim 1, wherein the leak path is formed in the diaphragm. A pilot valve seat formed on a holder holding the main valve element and the diaphragm, and a state in which the pilot valve is biased in a valve closing direction from a downstream side of the main valve against the pilot valve seat. 2. The engine cooling water control valve according to claim 1, further comprising: a pilot valve element arranged in a direction indicated by the arrow, and a solenoid for controlling the pilot valve element in a valve closing direction according to a value of a control current. The solenoid includes a movable iron core that is in contact with the pilot valve body, a fixed iron core that can move forward and backward in the axial direction in a state where a relative position with respect to the holder is fixed, and according to a value of the control current. An electromagnetic coil that controls a gap between the movable iron core and the fixed iron core, and a pilot valve that is disposed between the movable iron core and the fixed iron core and that fully opens the pilot valve when the electromagnetic coil is de-energized; 4. The engine cooling water control valve according to claim 3, further comprising: a first spring that maintains the engine cooling water. The fixed iron core is maintained at a distance from the holder by a shaft disposed through the movable iron core, and is urged to abut the shaft by a second spring. Item 5. An engine cooling water control valve according to Item 4. In an engine cooling water control valve for controlling an engine cooling water temperature,
A main valve arranged in the passage between the inlet and outlet of the cooling water,
A diaphragm fixed to the main valve body of the main valve to open and close the main valve body and define a pressure chamber isolated from the inlet;
A pilot valve that is arranged between the pressure chamber and the piping on the upstream side of the radiator and whose opening is set by an externally controllable solenoid force to control the pressure of the pressure chamber;
A leak path for communicating the pressure chamber with a space downstream of the main valve;
An engine cooling water control valve, comprising: In an engine cooling water control valve for controlling an engine cooling water temperature,
A main valve arranged in the passage between the inlet and outlet of the cooling water,
A diaphragm fixed to the main valve body of the main valve to open and close the main valve body and define a pressure chamber isolated from the inlet;
A leak path for introducing cooling water upstream of the radiator into the pressure chamber,
A pilot valve that is disposed between the pressure chamber and a space on the downstream side of the main valve, and whose opening is set by an externally controllable solenoid force to control the pressure of the pressure chamber,
An engine cooling water control valve, comprising:

Images