JP2003329167A - Thermostat device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact and inexpensive thermostat device of excellent working performance and simplified structure for controlling the flow of a cooling water in an engine cooling system from a small flow rate to a large flow rate at the temperature of the cooling water. <P>SOLUTION: A pressure chamber 12 is provided in the middle of a cooling water circuit 3 of an engine 1, which controls the flow of the cooling water in a cooling water passage 11 to constitute the cooling water circuit. A differential pressure valve 13 is provided to open/close an inlet side passage 11a to allow the cooling water to flow in and an outlet side passage 11b to allow the cooling water to flow out in a selectively communicable manner. In addition, a temperature sensing automatic valve 14 is provided continuous to the differential pressure valve, which is opened/closed by sensing the cooling water temperature to selectively communicate the pressure chamber with the outlet passage. A second inlet side passage 15 is provided, which allows the cooling water in the inlet side passage to flow into the pressure chamber, and an actuator 16 is provided to control the diameter of the second inlet side passage in a freely changeable manner. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to cooling an engine in which cooling water for cooling an internal combustion engine (hereinafter referred to as engine) used in an automobile or the like is circulated between a heat exchanger (hereinafter referred to as radiator). The present invention relates to a thermostat device used for variably controlling a cooling water temperature in a system.

[0002]

2. Description of the Related Art In an automobile engine, a water cooling type cooling system using a radiator is generally used for cooling the engine. Then, conventionally, in this type of cooling system, in order to control the temperature of the cooling water to be introduced into the engine, a thermostat using a thermal expansion body for adjusting the amount of cooling water circulated to the radiator side,
Alternatively, an electrically controlled valve unit is used.

That is, a control valve such as a thermostat using the above-mentioned thermal expansion body or a valve unit by electric control is provided in a part of the cooling water passage, for example, on the inlet side or the outlet side of the engine, and the cooling water temperature is increased. When the temperature is low, the control valve is closed and the cooling water is circulated through the bypass passage without passing through the radiator, and when the temperature of the cooling water is high, the control valve is opened and the cooling water is circulated through the radiator. And, the temperature of the cooling water can be controlled to a desired state.

By the way, in an engine cooling system using a thermostat or the like as described above, in recent cooling control, the engine is quickly warmed to clean exhaust gas quickly, and fuel consumption is improved (fuel consumption is improved). Therefore, there is a tendency to reduce the flow rate of the cooling water, such as reducing the friction of each part by maintaining the cooling water temperature at a high temperature. In the normal engine operating state, the cooling water control is performed only at a small flow rate when the thermostat is only slightly opened with respect to the maximum flow rate when the thermostat is fully opened.

On the other hand, the cooling water temperature needs to be lowered at the time of high load such as high-speed operation and climbing, and in order to prepare for such a case, the cooling water flow rate is higher than that normally used (thermostat fully open). Maximum flow rate in). Therefore, the conventional general thermostat has been designed so that a large flow rate can be controlled assuming such a case.

Further, in the control by the electric control valve unit, the engine cooling water temperature is designed to be optimized by arbitrarily changing the valve opening / closing temperature according to the engine load and the like.

[0007]

However, in the conventional engine cooling system as described above, in order to secure the cooling performance of the engine, it is necessary to control a large flow of cooling water, and the thermostat valve Although it is necessary to make the opening have a large diameter, such a large diameter causes a problem that it becomes difficult to control with a small flow rate as described above.

Further, with such a structure, since the cooling water flows at once immediately after the valve is opened, the temperature change becomes large and the temperature hunting is likely to occur. Further, in order to overcome the high water pressure due to the large flow rate, the components such as the return spring for urging the valve body also become large, and as a result, the thermostat itself becomes large. Further, there is a problem that the thermostat becomes large in resistance to the flow of the cooling water and the water flow resistance is increased due to the increase in the size of the thermostat.

Further, in the electric control valve unit, there is a problem in that the structure becomes complicated and the entire apparatus becomes large in size and cost.

The present invention has been made in view of such circumstances, and in an engine cooling system, the cooling water can be controlled appropriately and reliably from a small flow rate to a large flow rate according to the temperature of the cooling water. There is no risk of problems such as temperature hunting, and the overall structure is simplified.
Moreover, it is an object of the present invention to obtain a thermostat device which can be configured compactly and is inexpensive in cost.

[0011]

In order to meet such an object, a thermostat device according to the present invention (the invention according to claim 1) is provided in the middle of a cooling water circuit of an engine,
A pressure chamber capable of controlling the flow of cooling water in the cooling water passage forming the cooling water circuit, and an inlet side passage through which the cooling water flows in and an outlet side passage through which the cooling water flows out are selectively communicated. A differential pressure valve that opens and closes as much as possible, and is installed in parallel with the differential pressure valve,
It is characterized by comprising a temperature-sensing automatic valve capable of opening and closing by sensing the temperature of the cooling water to selectively open and close the pressure chamber and the outlet passage.

Further, the thermostat device according to the present invention (the invention according to claim 2) is the thermostat device according to claim 1 described above, wherein the second inlet side for allowing the cooling water in the inlet side passage to flow into the pressure chamber. It is characterized in that it is provided with a passage and an actuator for controlling the passage diameter of the second inlet passage to be changeable.

Further, the thermostat device according to the present invention (the invention according to claim 3) is the thermostat device according to claim 1 or 2, wherein cooling water does not stay in the pressure chamber and the engine cooling performance is improved. It is characterized in that a cooling water escape passage is provided to the extent that it does not affect the cooling water.

The present invention (the invention according to claims 1 to 3)
According to the authors, a single thermostat device consisting of a differential pressure valve and a temperature-sensing automatic valve attached to it has multiple valve functions with different flow rates, so under normal engine operating conditions, that is, at low flow rates. If it is possible to control the cooling water, the temperature sensing type automatic valve attached to the differential pressure valve (for example, a diaphragm valve) controls the minute flow rate. A large flow rate can be secured by opening the differential pressure valve. As a result, one thermostat device can control the cooling water from a small flow rate to a large flow rate without increasing the water flow resistance.

Further, the temperature sensing type automatic valve as the small flow rate control valve can be miniaturized, the structure can be simplified, the standard parts can be unified, and the durability and the cost can be reduced. It will be possible. In addition, the miniaturization of the temperature-sensing automatic valve as a small flow rate control valve simplifies the structure of the wax-type element, and it is possible to replace it with a simplified bimetal type or shape memory alloy. Become. Furthermore, since the small flow rate control valve and the large flow rate control valve are independent of each other, the small flow rate control valve opens immediately after the valve opens and a small amount of cooling water flows. The flow of water can prevent the temperature hunting that has occurred conventionally.

Further, according to the present invention (the invention according to claim 2), by changing and setting the opening diameter provided in the second inlet side passage by the actuator, the cooling water by the temperature sensing type automatic valve can be reduced. It is possible to change the timing (temperature) of switching from the control with the flow rate to the control with the large flow rate of the cooling water by the differential pressure valve. By doing so, it becomes possible to standardize and standardize the thermostat device, and one thermostat device can be applied to multiple models.
This is because the switching timing can be changed by setting the orifice diameter by an appropriate actuator in the second inlet passage.

Furthermore, a signal from an ECU (engine control unit) is output to a solenoid based on parameter information such as engine load information and outside air temperature, so that the passage diameter can be changed in a desired state according to operating conditions. Depending on the engine load information and the outside air temperature, etc., from a small flow rate of the thermostat device to a large flow rate, that is, from a small flow rate control of cooling water by a temperature sensing type automatic valve to a large flow rate by a differential pressure valve such as a diaphragm valve. It is possible to arbitrarily change the switching temperature of the cooling water control in the above.

Further, according to the present invention (the invention according to claim 3), the pressure chamber is provided with a cooling water escape passage (leak passage) in which cooling water does not stay and which does not affect the engine cooling performance. As a result, the flow of the cooling water is generated even when the thermostat device is closed, so that the thermal responsiveness of the temperature-sensitive automatic valve, that is, the responsiveness of the thermostat device is improved. Moreover, since only a small amount of cooling water needs to flow through the leak passage, there is an advantage that the responsiveness of the thermostat device is improved without affecting the engine cooling performance. Compared to the case without such a leak passage, the flow of cooling water is generated even when the valve is closed, so that the heat of the temperature-sensitive automatic valve provided in the pressure chamber is higher than that without the leak passage. This is because the responsiveness becomes good.

[0019]

1 to 4 show one embodiment of a thermostat device according to the present invention. In these drawings, first, an overall outline of a cooling water temperature control system for an automobile engine including a thermostat device will be described below with reference to FIG.

In FIG. 4, reference numeral 1 denotes an automobile engine as an internal combustion engine composed of a cylinder block and a cylinder head. In the cylinder block and cylinder head of the engine 1, a cooling water passage indicated by an arrow a is shown. Has been formed. Reference numeral 2 denotes a heat exchanger, that is, a radiator, and a cooling water passage 2c is formed in the radiator 2 as is well known, and a cooling water inlet portion 2a and a cooling water outlet portion 2b of the radiator 2 are connected to the engine 1. They are connected by a cooling water circuit 3 that circulates cooling water between them.

The cooling water circuit 3 has an outlet side cooling water passage 3a which communicates from a cooling water outlet 1c provided in the engine 1 to a cooling water inlet 2a provided in the radiator 2.
And an inflow side cooling water passage 3b which communicates from the cooling water outlet portion 2b provided in the radiator 2 to the cooling water inlet portion 1b provided in the engine 1 and the midway portions of these cooling water passages 3a, 3b. It is composed of a bypass passage 3c. The engine 1, the radiator 2 and the cooling water passage 3 form a cooling water circulation passage.

In this embodiment, the thermostat device 10 for controlling the flow and flow rate of the cooling water in the cooling water passage 3 according to the temperature of the cooling water flowing in the cooling water passage 3 is provided at the outlet side of the engine 1. In the middle of the cooling water channel 3a of
It is provided in a portion where distribution control is performed between the radiator 2 side and the bypass water passage 3c. With such a thermostat device 10, when the cooling water temperature is low, the cooling water is circulated through the bypass passage 3c, and when the cooling water temperature is high, the cooling water is cooled instead of the bypass passage 3c. The flow and the flow rate of the cooling water are controlled so as to be sent to the radiator 2 via the water passage 3a and circulated to the engine 1 side via the radiator 2.

Although not shown in FIG. 4, at the inlet portion 1b of the engine 1, the rotation shaft is rotated by the rotation of a crank shaft (not shown) of the engine 1 to force the cooling water in the cooling water passage 3. A water pump is arranged to circulate the water. Further, reference numeral 5 is a cooling fan unit for forcibly introducing cooling air into the radiator 2, and is composed of a fan and an electric motor for rotationally driving the fan.

According to the present invention, as the thermostat device 10 described above, as shown in FIGS. 1 and 2, the cooling water passage 11 is provided in the middle of the cooling water passage 3a from the engine 1 and constitutes the cooling water passage 3a. A pressure chamber 12 capable of controlling the flow of cooling water therein, an inlet side passage 11a into which the cooling water flows in, and an outlet side passage 11b into which the cooling water flows out.
And a diaphragm valve 13 as a differential pressure valve that selectively opens and closes the valve and a valve body 13a of the diaphragm valve 13.
And a temperature-sensing automatic valve 14 that can be opened and closed by sensing the temperature of the cooling water to selectively communicate the pressure chamber 12 and the outlet passage 11b.

To explain this in detail, in FIG. 1 and FIG.
Reference numerals 10a and 10b denote device housings. The device housings 10a and 10b are provided with a cooling water inlet portion 21 connected to the outlet portion 1c of the engine 1 and a cooling water outlet portion 22 connected to the radiator 2. There is. Further, a bypass connecting portion 23 connected to the bypass water channel 3c is provided.

A diaphragm valve 13 is provided in the middle of the cooling water passage 11 from the cooling water inlet portion 21 to the cooling water outlet portion 22 so that the passage can be opened and closed, and the pressure on the rear side of the valve body 13a is increased. A chamber 12 is provided.
In addition, 13b is a valve return spring that constantly urges the valve body 13a in the closing direction, and 13c is a valve seat portion on which the valve body 13a is seated.

The cooling water inlet portion 21 is connected to the bypass connecting portion 23 by a passage portion 23a, and the cooling water on the inlet side is an orifice passage provided as a second inlet side passage in a part of the housing 10b. It is configured to flow into the pressure chamber 12 via 15. Further, an actuator for controlling the passage diameter of the passage, for example, an electromagnetic solenoid 16 as shown in the drawing is attached to the orifice passage 15, and the passage diameter b is changed through the movable rod thereof. Has been done.

The temperature-sensing automatic valve 14 includes a wax element, etc., as is well known in the art.
A valve that uses the expansion and contraction of wax to open and close the valve body by circulating the cooling water by sensing the temperature of the cooling water, or a bimetal, and a valve that uses the deformation of the bimetal. A device having a structure for opening and closing the body may be appropriately used. Reference numeral 17 in the drawing denotes a return spring of the curved automatic valve 14, which keeps the valve closed at all times due to its urging force, and when the temperature of the cooling water becomes high, the temperature-sensitive automatic valve 14 The valve is opened against the urging force of the return spring 17 and functions to flow a predetermined flow rate of cooling water from the pressure chamber 12 to the outlet side passage 11b.

Further, the pressure chamber 12 is provided with a cooling water escape passage 18a or 18b to the extent that the cooling water does not stay therein and does not affect the engine cooling performance. Here, 18a is a relief passage by a small diameter hole formed in the valve body 13a of the diaphragm valve 13, and 18b is a passage provided in the housing 10b and connected to, for example, a water pump or the like, at least one of which may be provided. .

The thermostat device 10 having the above structure
Is operated as follows.

1. At low temperature (immediately after starting the engine, warming up)
When the temperature-sensing automatic valve 14 is not opened yet, the diaphragm valve 13 is pulled to the water pump side by the suction pressure of the water pump (not shown) from the radiator 2 side at the same time when the engine 1 is started. Therefore, the outlet side passage 11b is closed, and the discharge pressure from the engine 1 side is also applied to the pressure chamber 12 through the orifice passage 15, so that the cooling water hardly flows and the cooling water is generated by the heat generated by the engine 1. The temperature rises early.

At this time, the water pressure P2 in the inlet side passage 11a directly connected to the diaphragm valve 13 among the plurality of passages from the outlet side of the engine 1 and the orifice passage provided with the electromagnetic solenoid 16 which is the other inlet side passage The water pressure P1 in the pressure chamber 12 introduced from 15 has the same pressure.

2. At high temperature (end of warm-up, low load running, etc.)
When the temperature-sensing automatic valve 14 opens (at a small flow rate) and the temperature of the cooling water on the engine 1 side rises, the temperature-sensing automatic valve 14 attached to the diaphragm valve 13 causes the orifice passage 15 to move. Detecting a rise in the temperature of the cooling water flowing into the pressure chamber 12 via the valve, the valve is opened as shown by the imaginary line in FIG. 1, and the opening (small flow passage) from the pressure chamber 12 is provided to the radiator 2. The cooling water is flowed to the radiator 2 side by opening the outlet side passage 11b which communicates. As a result, the cooling water circulates between the engine 1 and the radiator 2.

Here, when the flow rate of the opening portion opened by the temperature sensing automatic valve 14 is smaller than the flow rate from the orifice passage 15 to the pressure chamber 12, the cooling water flows only from the temperature sensing automatic valve 14. , Out of the pressure chamber 12.

3. The diaphragm valve 1 opens when the temperature-sensing automatic valve 14 opens at high temperatures (such as when running under high load).
When the temperature of the cooling water on the engine 1 side further rises when 3 is also opened (at a large flow rate), the temperature-sensing automatic valve 14 attached to the diaphragm valve 13
The opening further expands, and the pressure passage 1 extends from the orifice passage 15.
The flow rate at the opening opened by the temperature-sensing automatic valve 14 is larger than the flow rate flowing into the valve 2. Further, the water pressure P2 of the cooling water on the inlet side passage 11a side also becomes larger than the water pressure P1 in the pressure chamber 12, so the diaphragm valve 13
Is separated from the valve seat portion 13c and pulled to the pressure chamber 12 side, so that the cooling water flows from the inlet side passage 11a to the outlet side passage 11b, and a large amount of cooling water flows out to the radiator 2 side. Become. When this happens,
The cooling water is further cooled by the radiator 2, and the temperature of the cooling water inside the engine 1 is lowered, so that the engine cooling function can be maximized.

According to this structure, the diaphragm valve 13 which is a differential pressure valve and the temperature-sensitive automatic valve 1 attached to the diaphragm valve 13 are provided.
Since one thermostat device 10 composed of 4 has a plurality of valve functions with different flow rates, the diaphragm is operated under normal engine operating conditions, that is, when cooling water can be controlled at a low flow rate. A minute flow rate is controlled by a temperature-sensing automatic valve 14 attached to the valve 13, and
When control at a large flow rate becomes necessary, it is possible to secure a large flow rate by opening the diaphragm valve 13 described above. As a result, with one thermostat device 10, it becomes possible to control the cooling water from a small flow rate to a large flow rate without increasing the water flow resistance in the cooling water circuit. The control of the small flow rate and the large flow rate by the thermostat device 10 is shown by a solid line in FIG. 3 in relation to the temperature of the cooling water.

Now, the operation of changing the passage diameter (opening diameter) in the orifice passage 15 will be described. That is, an electromagnetic solenoid 16 is provided in the orifice passage 15 and the opening diameter is arbitrarily changed, so that the pressure chamber 12
Since the cooling water pressure P1 applied to the valve changes, the relationship with the water pressure P2 on the inlet side passage 11a side and the flow rate in the orifice passage 15 change, it is possible to change the timing of switching from a small flow rate to a large flow rate. It will be.

As a result, the thermostat device 1 is based on the parameter information such as the engine load information and the outside air temperature.
The opening temperature of 0, that is, the timing and temperature from the small flow rate control of the cooling water by the temperature sensing type automatic valve 14 to the large flow rate control of the cooling water at the large flow rate by the differential pressure valve such as the diaphragm valve 13 are appropriately changed. Will be possible. Explaining this state with reference to FIG. 3, the differential pressure valve characteristic changes to the left and right depending on the diameter of the orifice passage 15 as shown by the arrow in the figure.

Therefore, when high load of the engine 1 continues, such as high-speed continuous running, uphill running, and high outside temperature, the orifice passage diameter is reduced and the amount of cooling water flowing into the pressure chamber 12 is reduced. By reducing the amount of water, the water pressure P1 of the cooling water in the pressure chamber 12 becomes small. On the other hand, since the pressure of P2 that causes the diaphragm valve 13 to act in the valve opening direction becomes strong, the valve body 13a opens promptly, and as a result, the switching timing to the large flow rate becomes faster, so that the cooling is performed. It is possible to set the water temperature lower. On the contrary, immediately after the engine is started, when the vehicle is traveling under a low load, or the like, the orifice passage diameter is increased and the amount of cooling water introduced into the pressure chamber 12 is increased, whereby the cooling water in the pressure chamber 12 is increased. The water pressure P1 becomes large. On the other hand, since the pressure of the water pressure P2 that acts on the diaphragm valve 13 in the valve opening direction becomes weak, the valve body 13a opens slowly, and as a result, the timing of switching to a large flow rate becomes late, so that cooling is performed. It is possible to set the water temperature higher.

Further, according to the thermostat device 10 having the above-described structure, the temperature sensing type automatic valve 14 as the small flow rate control valve can be downsized, the structure can be simplified, the parts can be shared, and the standard parts can be unified. It is also possible to improve the durability, improve the durability, and reduce the cost. In addition, the temperature-sensing automatic valve 14 as a small flow rate control valve
The miniaturization of the wax type makes it possible to simplify the structure of the wax type element, and further, to replace it with a valve element using a simplified bimetal type or shape memory alloy.

Further, since the small flow rate control valve and the large flow rate control valve are independent such as the temperature sensing type automatic valve 14 and the diaphragm valve 13, the small flow rate control valve opens immediately after opening. A small amount of cooling water flows, and a large amount of cooling water flows at once, so that temperature hunting that has conventionally occurred can be prevented.

Further, the diameter of the orifice passage 15 provided as the second inlet side passage is changed by an actuator,
By setting it, the temperature sensing type automatic valve 14 controls the cooling water with a small flow rate, and the differential pressure valve (diaphragm valve 1
It is possible to change the timing (temperature) of switching to control with a large flow rate of cooling water according to 3). By doing so, the thermostat device 10 can be standardized and standardized, and one thermostat device 10 can be applied to multiple models. This is because the switching timing can be arbitrarily changed by setting the orifice passage diameter by the actuator in the orifice passage 15.

Further, the thermostat device 10 described above.
According to the above, by outputting a signal from the ECU (engine control unit) to the electromagnetic solenoid 16 based on the engine load information and the parameter information such as the outside air temperature, the orifice passage diameter can be appropriately set according to the operating condition. The temperature of the thermostat device 10 can be changed according to the engine load information, the outside air temperature, etc.
From a small flow rate at a valve opening temperature to a large flow rate, that is, from a small flow rate control of cooling water by the temperature sensing type automatic valve 14 to a timing (temperature) of cooling water control at a large flow rate by a differential pressure valve such as the diaphragm valve 13. It is possible to change it arbitrarily.

Further, the thermostat device 10 described above.
According to this, by providing the pressure chamber 12 with the cooling water escape passage (leak passage) 18a or 18b to the extent that the cooling water does not stay and does not affect the engine cooling performance, even when the thermostat device 10 is closed. , Because the flow of cooling water is generated, the thermal response of the temperature-sensing automatic valve 14,
That is, the responsiveness of the thermostat device 10 can be improved. Moreover, the escape passage 18a or 18b
Since it suffices to flow a small amount of cooling water, there is an advantage that the responsiveness of the thermostat device 10 is improved without affecting the engine cooling performance. This is because a temperature-sensing automatic valve provided in the pressure chamber 12 is provided for the case where there is no escape passage by causing the flow of cooling water even when the valve is closed, as compared with the case where such an escape passage is not provided. This is because the thermal response of No. 14 becomes good.

It is needless to say that the present invention is not limited to the structure described in the above embodiment, and the shape, structure, etc. of each part of the thermostat device 10 can be appropriately modified or changed. For example, in the above-described embodiment, the case where the thermostat device 10 is provided on the outlet side of the engine 1 has been described, but the present invention is not limited to this. When the thermostat device 10 is provided on the inlet side of the engine 1, the cooling water inlet portion 21 is connected to the outlet portion 22 of the radiator 2, and the cooling water outlet portion 22 is provided on the water pump side provided at the inlet portion of the engine 1. Connect to. At this time, the bypass connection portion 23 is removed.

Further, in the above-described embodiment, the case where the diaphragm valve 13 is used as the differential pressure valve and the wax type element is used as the temperature sensing type automatic valve 14 has been described, but the present invention is not limited to this. Any valve that can operate can be freely adopted. Furthermore, the second
The electromagnetic solenoid 16 is also used as an actuator for varying the passage diameter of the orifice passage as the inlet side passage of
It is not limited to.

[0047]

As described above, according to the thermostat device of the present invention, one thermostat device comprising a differential pressure valve and a temperature-sensing automatic valve attached thereto has a plurality of valve functions of different flow rates. Therefore, under normal engine operating conditions, that is, when the cooling water can be controlled with a small flow rate, such as when the load is relatively small, the temperature attached to the differential pressure valve (for example, diaphragm valve) When a small flow rate is controlled by the sensing type automatic valve and control at a large flow rate is required, it is possible to secure a large flow rate by opening the differential pressure valve described above. As a result, one thermostat device can control the cooling water from a small flow rate to a large flow rate without increasing the water flow resistance.

Further, the temperature sensing type automatic valve as the small flow rate control valve can be miniaturized, the structure can be simplified and the standard parts can be unified, and the durability and the cost can be reduced. It will be possible. In addition, the miniaturization of the temperature-sensing automatic valve as a small flow rate control valve simplifies the structure of the wax-type element, and it is possible to replace it with a simplified bimetal type or shape memory alloy. Become.

Further, according to the present invention, since the small flow control valve and the large flow control valve are independent of each other, the small flow control valve is opened immediately after the valve is opened and a small amount of cooling water flows. As a result, the temperature hunting that has conventionally occurred due to a large flow of cooling water flowing at once can be prevented.

Further, according to the present invention, the opening diameter provided in the second inlet passage is changed and set by the actuator, so that the differential pressure valve can be controlled by controlling the temperature sensing type automatic valve with a small flow rate of the cooling water. It is possible to change the timing (temperature) of switching to control with a large flow rate of cooling water by. By doing so, it becomes possible to standardize and standardize the thermostat device, and one thermostat device can be applied to multiple models.

Furthermore, by outputting a signal from an ECU (engine control unit) to a solenoid based on parameter information such as engine load information and outside air temperature, the passage diameter can be appropriately changed according to operating conditions. Therefore, the switching temperature of the cooling water control from a small flow rate of the thermostat device to a large flow rate, that is, from a small flow rate control of the cooling water by the temperature sensing type automatic valve to a large flow rate by the differential pressure valve such as a diaphragm valve can be arbitrarily set. Since it can be changed, the cooling water temperature can be arbitrarily controlled according to the engine load information, the outside air temperature, and the like.

Further, according to the present invention, the pressure chamber is provided with the cooling water escape passage to the extent that the cooling water does not stay and does not affect the engine cooling performance, so that the cooling is performed even when the thermostat device is closed. Since the flow of water is generated, the thermal response of the temperature-sensitive automatic valve, that is, the response of the thermostat device is improved. Moreover, since only a small amount of cooling water needs to flow through the leak passage, there is an advantage that the responsiveness of the thermostat device is improved without affecting the engine cooling performance.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of an essential part structure of a thermostat device according to one embodiment of the present invention when a cooling water temperature is in a low temperature state.

FIG. 2 is a schematic cross-sectional view when the cooling water temperature changes from the state of FIG. 1 to a high temperature state.

FIG. 3 is a graph for explaining a flow rate control state of cooling water by the thermostat device according to the present invention.

FIG. 4 is a schematic configuration diagram for explaining an outline of a suitable engine cooling water circuit to which the thermostat device according to the present invention is applied.

[Explanation of symbols]

1 ... Engine, 2 ... Radiator, 3 ... Cooling channel, 10 ...
Thermostat device, 11 ... Cooling water passage, 11a ... Inlet side passage, 11b ... Outlet side passage, 12 ... Pressure chamber, 13 ... Diaphragm valve (differential pressure valve), 13a ... Valve body, 13b ... Return spring, 13c ... Valve seat part , 14 ... Temperature-sensing automatic valve, 15 ... Orifice passage (second inlet side passage), 16 ... Electromagnetic solenoid (actuator), 17
... Return spring, 18a, 18b ... Cooling water escape passage, 21 ... Cooling water inlet, 22 ... Cooling water outlet, 23
… Bypass connections.

Claims (3)

[Claims] 1. A pressure chamber provided in the middle of a cooling water circuit of an engine for controlling the flow of cooling water in a cooling water passage forming the cooling water circuit, and an inlet side into which the cooling water flows. A differential pressure valve for selectively opening and closing a passage and an outlet-side passage through which cooling water flows, and a differential pressure valve that is installed in parallel with the differential pressure valve and opens and closes by sensing a cooling water temperature to open and close the pressure chamber and the outlet passage. And a temperature-sensing automatic valve capable of selectively communicating with the thermostat device. 2. The thermostat device according to claim 1, further comprising a second inlet-side passage through which cooling water in the inlet-side passage flows into the pressure chamber, and a passage diameter of the second inlet-side passage. A thermostat device, which is provided with an actuator for freely changing the temperature. 3. The thermostat device according to claim 1 or 2, wherein the pressure chamber is provided with a cooling water escape passage to the extent that cooling water does not stay and does not affect engine cooling performance. Thermostat device.