JP2021055629A - Thermostat device - Google Patents

Abstract

To provide a thermostat device capable of improving thermal responsiveness to a temperature change of cooling water while promoting temperature rise from the low-temperature state of the cooling water in an engine.SOLUTION: A thermostat device U1 which is arranged in an engine cooling circuit U for controlling a circulation route for cooling water flowing from an engine U2 to a radiator U3, includes a housing 1, a valve element 3 provided in a passage hole 1M of the housing 1 for switching between the opening state and the closing state of the passage hole 1M according to the operation of a thermal responsive part 2, a leak passage 6 provided in the housing 1 or the valve element 3, and communicated at one end with the passage hole 1M on the upstream side of the valve element 3 and communicated at the other end with the passage hole 1M on the downstream side of the valve element 3, and a relief valve 7 for switching between the opening state and the closing state of the leak passage 6 according to the state of the cooling water.SELECTED DRAWING: Figure 2

Description

The present disclosure relates to a thermostat device.

Conventionally, a thermostat device that is arranged in an engine cooling circuit and controls a circulation path of cooling water flowing in the engine cooling circuit is known (see, for example, Patent Document 1).

This type of thermostat device opens the valve when the temperature of the cooling water in the engine (that is, the water jacket) reaches the valve opening reference temperature so that the cooling water flowing through the engine is directed to the radiator. Is set to. Then, this type of thermostat device blocks the flow of cooling water from the engine to the radiator while the temperature of the cooling water in the engine is low, such as when the engine is started, and the cooling water in the engine is used as the radiator. Immediately return to the engine via the bypass passage without passing through.

The engine cooling circuit quickly raises the temperature of the cooling water when the temperature of the cooling water in the engine is low due to the operation of the thermostat device, and when the temperature of the cooling water in the engine rises above the valve opening reference temperature. , A radiator is used to reduce the temperature of the cooling water.

In this type of thermostat device, for example, wax is used as a temperature sensitive member. Then, the thermostat device expands (that is, melts) / contracts (that is, that is, melts) the wax depending on the temperature of the cooling water that comes into contact with the temperature-sensitive case (hereinafter, also referred to as “temperature-sensitive portion”) that stores the wax. It is configured to (solidify) and operate the valve body provided in the passage hole of the housing.

Japanese Unexamined Patent Publication No. 2016-003578

By the way, in this type of thermostat device, when the passage hole of the housing is closed by the valve body (hereinafter referred to as "when the valve is closed"), the cooling water flowing through the passage hole is felt. Since the heat is not recirculated to the hot part, the amount of heat transferred from the cooling water to the temperature sensitive part is reduced, and there is a problem that the valve opening of the valve body is delayed. That is, in such a case, the valve opening of the thermostat device is performed after the temperature of the cooling water becomes considerably higher than the valve opening reference temperature.

Against this background, the inventors of the present application, as a measure to suppress the delay in the valve opening timing of the thermostat device, always pass the cooling water flowing from the engine side to the radiator side to the valve body or housing of the thermostat device. A structure was investigated to increase the amount of heat received by the wax when the valve is closed by providing a leak hole that enables conduction. However, when the inventors of the present application provide such a leak hole, the cooling water in the engine is circulated to the radiator side even when the cooling water in the engine is in a low temperature state, so that the cooling water in the engine is circulated. I came up with the problem of hindering the temperature rise.

The present disclosure has been made in view of the above problems, and makes it possible to improve the thermal responsiveness to a temperature change of the cooling water while promoting the temperature rise of the cooling water in the engine from a low temperature state. It is an object of the present invention to provide a thermostat device.

The main disclosure that solves the above-mentioned problems is
A thermostat device that is installed in the engine cooling circuit and controls the circulation path of the cooling water that flows from the engine to the radiator.
A housing having a passage hole through which the cooling water flows, and an input port, an output port, and a branch port for bypass communicating with the passage hole.
A heat-responsive portion that is movably supported with respect to the housing in the passage hole,
A valve body that is joined to the heat-responsive portion in the passage hole and switches between an open state and a closed state of the passage hole according to the operation of the heat-responsive portion.
A leak passage provided in the housing or the valve body, one end communicating with the passage hole on the upstream side of the valve body and the other end communicating with the passage hole on the downstream side of the valve body.
A relief valve that switches between an open state and a closed state of the leak passage according to the state of the cooling water.
It is a thermostat device equipped with.

According to the thermostat device according to the present disclosure, it is possible to improve the thermal responsiveness to the temperature change of the cooling water while promoting the temperature rise of the cooling water in the engine from the low temperature state.

The figure which shows the engine cooling circuit which concerns on one Embodiment The figure which shows the structure of the thermostat apparatus which concerns on one Embodiment The figure which shows the detailed structure of the relief valve which concerns on one Embodiment The figure which shows an example of the behavior of a thermostat device, a relief valve, a cooling water pressure, an engine load, and a cooling water temperature which concerns on one Embodiment.

Preferred embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. In the present specification and the drawings, components having substantially the same function are designated by the same reference numerals, so that duplicate description will be omitted.

[Engine cooling circuit]
First, an example of the configuration of the engine cooling circuit to which the thermostat device according to the present embodiment is applied will be described with reference to FIG. The thermostat device according to the present embodiment is mounted on a vehicle together with, for example, an engine and a radiator.

FIG. 1 is a diagram showing an engine cooling circuit U according to the present embodiment.

The engine cooling circuit U is a circulation path for cooling water for cooling the engine U2. The engine cooling circuit U according to the present embodiment circulates cooling water via a thermostat device U1, an engine U2, a radiator U3, a water pump U4, an air conditioner heater U5, a transmission heater U6, and an EGR cooler U7.

Specifically, the engine cooling circuit U according to the present embodiment has a feed passage T1, a return passage T2, a first branch passage T3, a second branch passage T4, a bypass passage Tp1, and so on.

Here, the feed passage T1 connects the cooling water outlet of the radiator U3 and the cooling water inlet of the engine U2, and allows the cooling water cooled by the radiator U3 to flow to the engine U2. A water pump U4 is provided in the feed passage T1, and thrust is applied to the cooling water by the water pump U4 so that the cooling water circulates in the engine cooling circuit U.

The cooling water flowing into the cooling water inlet of the engine U2 cools the oil cooler U2c, the cylinder block U2b, the cylinder head U2a, and the EGR cooler U7. Here, most of the cooling water delivered into the engine U2 passes through the water jacket formed on the oil cooler U2c, the cylinder block U2b, and the cylinder head U2a, and then heads for the return passage T2.

A part of the cooling water that has flowed into the cooling water inlet of the engine U2 passes through the water jacket formed on the oil cooler U2c, the cylinder block U2b, and the cylinder head U2a, and then heads for the first branch flow path T3. Further, the other part of the cooling water that has flowed into the cooling water inlet of the engine U2 branches from the oil cooler U2c, the cylinder block U2b, and the cylinder head U2a side, passes through the second branch flow path T4, and is an EGR cooler. After cooling the U7, it is returned to the feed passage T1.

The first branch flow path T3 sends a part of the cooling water absorbed by the engine U2 to the feed passage T1 after passing through the heat exchangers of the air conditioner heater U5 and the transmission heater U6. At this time, the heat exchanger of the air conditioner heater U5 warms the air sent to the inside of the vehicle by the heat obtained from the cooling water. Further, the heat exchanger of the transmission heater U6 warms the lubricating oil of the transmission by the heat obtained from the cooling water.

The return passage T2 connects the cooling water outlet of the engine U2 and the cooling water inlet of the radiator U3, and allows the cooling water absorbed by the engine U2 to flow to the radiator U3. A thermostat device U1 is provided in the return passage T2, and the circulation path of the cooling water sent from the engine U2 to the return passage T2 is controlled by the thermostat device U1.

Specifically, the thermostat device U1 allows the cooling water sent from the engine U2 to the return passage T2 to flow through either the radiator U3 or the bypass passage Tp1 under the control of its own valve body (see FIG. 2). And later).

When the temperature of the cooling water exceeds the valve opening reference temperature, the thermostat device U1 directs the cooling water sent from the engine U2 to the return passage T2 to the radiator U3 side as it is. On the other hand, when the temperature of the cooling water is equal to or lower than the valve opening reference temperature, the thermostat device U1 directs the cooling water sent from the engine U2 to the return passage T2 toward the bypass passage Tp1, bypasses the radiator U3, and sends the cooling water. Return to passage T1.

The bypass passage Tp1 is provided so as to branch from the middle of the return passage T2, and the cooling water from the engine U2 to the radiator U3 is sent to the feed passage T1 by bypassing the radiator U3 and returned to the cooling water inlet of the engine U2. ..

The feed passage T1, the return passage T2, the first branch passage T3, the second branch passage T4, and the bypass passage Tp1 are made of, for example, a hose material.

[Thermostat device]
Next, an example of the configuration of the thermostat device U1 according to the present embodiment will be described with reference to FIGS. 2 to 4. The thermostat device U1 according to the present embodiment is, for example, a wax type thermostat device.

FIG. 2 is a diagram showing a configuration of a thermostat device U1 according to the present embodiment. In the following, in order to clarify the positional relationship of each configuration, the flow direction of the cooling water flowing through the passage hole 1M of the thermostat device U1 is referred to as "downstream side" (upward direction in FIG. 2) for cooling. The direction opposite to the water flow direction will be referred to as "upstream side" (downward direction in FIG. 2).

The thermostat device U1 includes a housing 1, a heat receiving portion 2, a valve body 3, a frame 4, a spring 5, a leak passage 6, and a relief valve 7.

The housing 1 is arranged in the return passage T2 of the engine cooling circuit U. The housing 1 has a passage hole 1M, an input port 1a, an output port 1b, and a branch port 1c.

Here, the input port 1a receives the cooling water sent from the cooling water outlet of the engine U2. Further, the passage hole 1M allows the cooling water received by the input port 1a to flow through. The output port 1b is provided on the downstream side of the valve body 3, and sends the cooling water flowing through the passage hole 1M to the radiator U3. Further, the branch port 1c (“branch port for bypass” of the present invention) constitutes a part of the bypass passage Tp1 and is provided so as to branch from the passage hole 1M on the upstream side of the valve body 3 and is provided so as to branch from the passage hole 1M. The cooling water flowing inside is sent to the bypass passage Tp1.

The heat-responsive portion 2 is supported in the passage hole 1M so as to be able to move along the extending direction of the passage hole 1M. Here, the heat-responsive portion 2 is supported by a frame 4 fixed to the inner wall of the housing 1.

The heat-responsive portion 2 includes, for example, a temperature-sensitive case 2a in which wax is stored, and a piston pin 2b that moves upstream or downstream in response to expansion or compression of the wax in the temperature-sensitive case 2a. Will be done. Here, the temperature sensitive case 2a is arranged on the upstream side of the valve body 3. Further, the piston pin 2b is arranged so as to project downstream from the temperature sensitive case 2a and have its tip abut on the frame 4.

For example, when the temperature of the cooling water is low, the heat-responsive portion 2 keeps the piston pin 2b in a contracted state, and expands the piston pin 2b to the downstream side as the temperature of the cooling water rises. As a result, the heat-responsive portion 2 (temperature-sensitive case 2a) moves in the direction opposite to the direction in which the tip of the piston pin 2b tends to expand (here, the upstream side) due to the reaction force from the frame 4.

The frame 4 extends in the passage hole 1M along the extending direction of the passage hole 1M, and the flange portion 4a of the frame 4 is fixed to the inner wall of the housing 1. The frame 4 movably supports the heat-responsive portion 2 to the upstream side or the downstream side, and also supports one end of the spring 5 on the upstream side of the heat-responsive portion 2.

The spring 5 is arranged so as to be interposed between the valve body 3 and the frame 4, and urges the valve body 3 toward the flange portion 4a.

The valve body 3 is joined to the heat-responsive portion 2 in the passage hole 1M, and as the heat-responsive portion 2 moves upstream or downstream along the extending direction of the passage hole 1M, the passage hole 1M is formed. Open or block.

More specifically, the valve body 3 is joined to the heat-responsive portion 2 so as to be located near the opening of the flange portion 4a of the frame 4 fixed to the inner wall of the housing 1. The valve body 3 is arranged in a state of being urged by a spring 5 interposed between the valve body 3 and the frame 4 on the side that closes the opening of the flange portion 4a (here, the downstream side). Then, in the state where the heat-responsive portion 2 is contracted, the valve body 3 closes the opening of the flange portion 4a by the urging force of the spring 5, thereby closing the passage hole 1M. Further, when the heat-responsive portion 2 expands, the valve body 3 moves to the side where the opening of the flange portion 4a is opened against the urging force of the spring 5 due to the expansion force of the heat-responsive portion 2. As a result, the passage hole 1M is opened.

The leak passage 6 is formed in the housing 1 so that one end communicates with the passage hole 1M on the upstream side of the valve body 3 and the other end communicates with the passage hole 1M on the downstream side of the valve body 3. The leak passage 6 suppresses all of the cooling water flowing into the input port 1a from flowing into the bypass passage T1p when the thermostat device U1 is closed, and is one of the cooling waters flowing into the input port 1a. The unit is directed to the output port 1c via itself. As a result, even when the thermostat device U1 is closed, the thermostat device U1 can be recirculated around the temperature sensitive case 2a via the leak passage 6.

The relief valve 7 switches between an open state and a closed state of the leak passage 6 according to the state of the cooling water in the engine cooling circuit U. The relief valve 7 typically closes the leak passage 6 when the cooling water in the engine U2 is in a low temperature state, and when the temperature of the cooling water approaches the valve opening reference temperature or the temperature of the cooling water. Is presumed to approach the valve opening reference temperature, it operates so as to open the leak passage 6.

The relief valve 7 is, for example, a pressure-operated valve that operates to open or close the leak passage 6 according to the pressure of the cooling water flowing on the upstream side of the valve body 3 (see FIG. 3). The relief valve 7 is composed of, for example, a ball body 7a arranged in the leak passage 6 and an urging spring 7b for urging the ball body 7a. In FIG. 3, the leak passage 6 communicates with the valve arrangement space 6a extending upward from the leak passage 6, and the ball body 7a and the urging spring 7b form the valve arrangement space. It is arranged in 6a.

The ball body 7a has, for example, a diameter substantially the same as the diameter of the leak passage 6, and is configured to be able to block the leak passage 6. The ball body 7a is arranged so as to be able to enter the leak passage 6 and to be retracted into the valve arrangement space 6a in the boundary region between the valve arrangement space 6a and the leak passage 6. Further, one end of the urging spring 7b is connected to the ball body 7a, and the other end is connected to the upper end of the valve arrangement space 6a to urge the ball body 7a downward.

With this configuration, when the pressure of the cooling water flowing on the upstream side of the valve body 3 is low, the relief valve 7 allows the ball body 7a to enter the leak passage 6 side by the urging force of the urging spring 7b, and the leak passage 6 is closed. Further, when the pressure of the cooling water flowing on the upstream side of the valve body 3 becomes high, the ball body 7a retracts into the valve arrangement space 6a against the urging force of the urging spring 7b, and the leak passage. Open 6

Here, the pressure of the cooling water flowing through the engine cooling circuit U depends on the pump output of the water pump U4. The water pump U4 adjusts the output based on, for example, the engine load. When the engine load is small, the pump output is also reduced, and when the engine load is large, the pump output is also increased. In other words, when the engine load increases, the water pump U4 increases the pump output in order to increase the amount of heat radiated from the cooling water in the radiator U3. Then, depending on the increase in the pump output of the water pump U4, the pressure of the cooling water flowing through the engine cooling circuit U also increases. The water pump U4 has acquired engine output information from the vehicle ECU (not shown), for example, and has detected that the engine U2 has been in high load operation.

That is, the relief valve 7 operates so as to open the leak passage 6 when the pump output of the water pump U4 increases when the engine load increases and the cooling water temperature tends to rise. As a result, the relief valve 7 opens the leak passage 6 before the cooling water temperature reaches the valve opening reference temperature. As a result, a flow circulating around the temperature sensitive case 2a is generated via the leak passage 6.

Here, the operation of the thermostat device U1 according to the present embodiment will be described with reference to FIG.

FIG. 4 is a diagram showing an example of the behavior of the thermostat device U1, the relief valve 7, the cooling water pressure [Pa], the engine load [W], and the cooling water temperature [° C.].

FIG. 4 shows, as an example, the behavior of the thermostat device U1 until the valve is opened when the vehicle is loaded with luggage and is in high-load operation.

When the vehicle is in a low load operation state (timing T0), the cooling water is in a low temperature state, and the thermostat device U1 is in a valve closed state. At this time, the water pump U4 sets the pump output to a small output, and the relief valve 7 maintains the leak passage 6 in a closed state.

Therefore, at this time, all of the cooling water that has flowed into the input port 1a of the thermostat device U1 flows through the bypass passage Tp1 via the branch port 1c without being sent to the radiator U3 side.

When the engine U2 is in high load operation (timing T1) due to loading a load on the vehicle or the like, the cooling water absorbs heat from the engine U2 and starts to rise in temperature.

Then, when the engine U2 is in high load operation, the water pump U4 increases the pump output (timing T2). As the water pump U4 increases the pump output, the pressure of the cooling water circulating in the engine cooling circuit U also increases. As a result, the relief valve 7 opens the leak passage 6.

As a result, before the temperature of the cooling water circulating in the engine cooling circuit U rises to the valve opening reference temperature, a part of the cooling water flowing into the input port 1a is passed through the leak passage 6 to the output port 1b. It begins to flow to the side. At this time, the cooling water flowing to the output port 1b side via the leak passage 6 is also circulated in the vicinity of the temperature sensitive case 2a of the heat receiving portion 2, thereby increasing the amount of heat received in the temperature sensitive case 2a. become.

Then, as the temperature of the cooling water sent from the engine U2 side rises to the valve opening reference temperature, the wax in the temperature sensitive case 2a expands (timing T3). As a result, the thermostat device U1 moves the valve body 3 to open the passage hole 1M. As a result, when the temperature of the cooling water rises, the cooling water that has flowed into the input port 1a of the thermostat device U1 is sent to the radiator U3 via the output port 1b and cooled.

In this way, the thermostat device U1 controls the circulation path of the cooling water in the engine cooling circuit U, and when the temperature of the cooling water in the engine U2 is low, the temperature of the cooling water is rapidly raised in the engine U2. When the temperature of the cooling water rises to the valve opening reference temperature, the temperature of the cooling water is lowered by the radiator U3.

[effect]
As described above, in the thermostat device U1 according to the present embodiment, one end communicates with the passage hole 1M on the upstream side of the valve body 3, and the other end communicates with the passage hole 1M on the downstream side of the valve body 3. And a relief valve 7 that switches between an open state and a closed state of the leak passage 6 according to the state of the cooling water.

Therefore, according to the thermostat device U1 according to the present embodiment, when the temperature of the cooling water in the engine U2 is low, the leak passage 6 is kept closed and the cooling water flows into the radiator U3 side. Can be suppressed. Then, when it is estimated that the temperature of the cooling water approaches the valve opening reference temperature, the leak passage 6 is opened and the cooling water is circulated around the temperature sensitive case 2a via the leak passage 6. be able to.

Thereby, it is possible to improve the thermal responsiveness to the temperature change of the cooling water while promoting the temperature rise of the cooling water in the engine U2 from the low temperature state. That is, this makes it possible to suppress a delay in the valve opening timing of the thermostat device U1.

Further, since the relief valve 7 of the thermostat device U1 according to the present embodiment is composed of a pressure-operated valve, the relief valve 7 operates reliably (that is, the valve is opened) before the temperature of the cooling water rises to the valve opening reference temperature. ) Is possible.

(Other embodiments)
The present invention is not limited to the above embodiment, and various modifications can be considered.

In the above embodiment, as an example of the thermostat device U1, a mode in which the leak passage 6 is provided in the housing 1 is shown. However, instead of this, the leak passage 6 may be arranged in the valve body 3.

Further, in the above embodiment, as an example of the thermostat device U1, a mode in which the relief valve 7 is configured by a pressure-operated valve is shown. However, instead of this, it may be configured by the relief valve 7 of the thermal actuated valve. However, when the relief valve 7 is composed of a heat-operated valve, the problem of thermal responsiveness arises as in the case of the heat-responsive portion 2 of the thermostat device U1, so the relief valve 7 is composed of a pressure-operated valve. Is desirable.

Further, in the above embodiment, as an example of the water pump U4, an aspect of controlling its own pump output based on the engine load is shown. However, the water pump U4 may control its own pump output in place of or together with the engine load by referring to the elapsed time from the start of the engine, the cooling water temperature, and the like. ..

Further, in the above embodiment, the vehicle is shown as an example of the application target of the thermostat device U1, but the application target of the thermostat device U1 is not limited to this. For example, the thermostat device U1 may be applied to a generator, a construction machine, a ship, or the like.

Although specific examples of the present invention have been described in detail above, these are merely examples and do not limit the scope of claims. The techniques described in the claims include various modifications and modifications of the specific examples illustrated above.

According to the thermostat device according to the present disclosure, it is possible to improve the thermal responsiveness to the temperature change of the cooling water while promoting the temperature rise of the cooling water in the engine from the low temperature state.

1 Housing 1M Passage hole 1a Input port 1b Output port 1c Branch port 2 Heat response part 2a Temperature sensitive case 2b Piston pin 3 Valve body 4 Frame 4a Flange part 5 Spring 6 Leak passage 7 Relief valve U Engine cooling circuit U1 Thermostat device U2 Engine U2a Cylinder head U2b Cylinder block U2c Oil cooler U3 Radiator U4 Water pump U5 Air conditioner heater U6 Transmission heater U7 EGR cooler T1 Feed passage T2 Return passage T3 First branch flow path T4 Second branch flow path Tp1 Bypass passage

Claims (4)

A thermostat device that is installed in the engine cooling circuit and controls the circulation path of the cooling water that flows from the engine to the radiator.
A housing having a passage hole through which the cooling water flows, and an input port, an output port, and a branch port for bypass communicating with the passage hole.
A heat-responsive portion that is movably supported with respect to the housing in the passage hole,
A valve body that is joined to the heat-responsive portion in the passage hole and switches between an open state and a closed state of the passage hole according to the operation of the heat-responsive portion.
A leak passage provided in the housing or the valve body, one end communicating with the passage hole on the upstream side of the valve body and the other end communicating with the passage hole on the downstream side of the valve body.
A relief valve that switches between an open state and a closed state of the leak passage according to the state of the cooling water.
Thermostat device equipped with. The relief valve is a pressure-operated valve that operates to switch between an open state and a closed state of the leak passage according to the pressure of the cooling water flowing on the upstream side of the valve body. The thermostat device described. The one end of the leak passage communicates with the passage hole on the upstream side of the valve body and on the downstream side of the temperature-sensitive portion of the heat-responsive portion.
The thermostat device according to claim 1 or 2. When the temperature of the cooling water rises from a low temperature state, the timing at which the relief valve opens the leak passage is earlier than the timing at which the valve body opens the passage hole.
The thermostat device according to any one of claims 1 to 3.

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