CN114514365A

CN114514365A - Thermostat device

Info

Publication number: CN114514365A
Application number: CN202080067007.9A
Authority: CN
Inventors: 戸田聡; 三轮纯一; 梶山昌宏; 渡邉秀次; 渡边正人
Original assignee: Isuzu Motors Ltd
Current assignee: Isuzu Motors Ltd
Priority date: 2019-09-30
Filing date: 2020-09-30
Publication date: 2022-05-17
Anticipated expiration: 2040-09-30
Also published as: CN114514365B; JP2021055629A; WO2021066014A1

Abstract

A thermostat device (U1) is disposed in an engine cooling circuit (U) and controls a circulation path of cooling water flowing from an engine (U2) to a radiator (U3), and the thermostat device (U1) includes: a housing (1); a valve body (3) which is provided in the passage hole (1M) of the housing (1) and which switches between an open state and a closed state of the passage hole (1M) in accordance with the operation of the thermal actuator (2); a leakage passage (6) provided in the housing (1) or the valve body (3), one end of the leakage passage communicating with the passage hole (1M) on the upstream side of the valve body (3), and the other end of the leakage passage communicating 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 leakage passage (6) in accordance with the state of the cooling water.

Description

Thermostat device

Technical Field

The present invention relates to a thermostat device.

Background

Conventionally, there is known a thermostat device which is disposed in an engine cooling circuit and controls a circulation path of cooling water flowing into the engine cooling circuit (for example, see patent document 1).

Such a thermostat device is set to open a valve when the temperature of the cooling water in the engine (i.e., the water jacket) reaches a valve-opening reference temperature, and to flow the cooling water flowing through the engine to the radiator. In addition, in such a thermostat device, while the temperature of the cooling water in the engine is low, such as when the engine is started, the flow of the cooling water from the engine to the radiator is shut off, and the cooling water in the engine is directly returned to the engine through the bypass passage without passing through the radiator.

The engine cooling circuit is configured to rapidly increase the temperature of the cooling water by the operation of the thermostat device when the temperature of the cooling water in the engine is low, and to decrease the temperature of the cooling water by the radiator when the temperature of the cooling water in the engine is increased to or above the valve opening reference temperature.

In addition, in such a thermostat device, for example, wax is used as the temperature sensing member. The thermostat device is configured to expand (i.e., melt) and contract (i.e., solidify) the wax in accordance with the temperature of the cooling water that comes into contact with a temperature sensing case (hereinafter also referred to as a "temperature sensing unit") that contains the wax, and to operate a valve body provided in a passage hole of the housing.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2016-.

Disclosure of Invention

Problems to be solved by the invention

However, in such a thermostat device, there are the following problems: when the passage hole of the housing is closed by the valve element (hereinafter referred to as "valve closing time"), no cooling water flowing through the passage hole flows around the temperature sensing unit, so that the amount of heat transferred from the cooling water to the temperature sensing unit is reduced, and the valve element is delayed from opening. That is, in such a case, the valve opening of the thermostat device is performed after the temperature of the cooling water is much higher than the valve opening reference temperature.

Under such a background, the inventors of the present application have studied the following configuration as a measure for suppressing the delay of the valve opening timing of the thermostat device: a leakage hole capable of always conducting cooling water flowing from an engine side to a radiator side is provided in a valve body or a housing of a thermostat device, thereby increasing the amount of heat received by wax when the valve is closed. However, the inventors of the present application also consider the following problems: in the case where such a leak hole is provided, even when the temperature of the cooling water in the engine is low, the cooling water is circulated to the radiator side, and therefore, the leakage hole becomes an obstacle when the temperature of the cooling water in the engine is raised.

The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a thermostat device that can promote a temperature rise of cooling water in an engine from a low temperature state and improve thermal responsiveness to a temperature change of the cooling water.

Means for solving the problems

As a main aspect of the present invention for solving the above problems, a thermostat device according to one aspect includes:

a passage hole for allowing cooling water to flow to the radiator;

a bypass branch port that branches from the passage hole;

a valve body that switches the passage hole between an open state and a closed state;

a leak passage capable of communicating an upstream side and a downstream side of the passage hole when the passage hole is in a closed state; and

and a relief valve that switches between an open state and a closed state of the leakage passage in accordance with a state of the cooling water.

A thermostat device according to another aspect is disposed in an engine cooling circuit and controls a circulation path of cooling water flowing from an engine to a radiator, the thermostat device including:

a housing, comprising: a passage hole through which the cooling water flows, and an input port, an output port, and a branch port for bypass, which are communicated with the passage hole;

a thermal element movably supported in the passage hole with respect to the housing;

a valve body engaged with the thermal actuator in the passage hole, and switching between an open state and a closed state of the passage hole according to an operation of the thermal actuator;

a leakage passage provided in the housing or the valve body, and having 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; and

Effects of the invention

According to the thermostat device of the present invention, it is possible to promote the temperature rise of the cooling water in the engine from a low temperature state and to improve the thermal responsiveness to the temperature change of the cooling water.

Drawings

FIG. 1 is a diagram illustrating an engine cooling circuit according to one embodiment;

fig. 2 is a diagram showing a structure of a thermostat device according to an embodiment;

fig. 3 is a diagram showing a detailed configuration of a relief valve according to an embodiment;

fig. 4 is a diagram showing an example of variations in the thermostat device, relief valve, coolant pressure, engine load, and coolant temperature according to one embodiment.

Detailed Description

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In the present specification and the drawings, the same reference numerals are given to the components having substantially the same function, and redundant description is omitted.

[ Engine Cooling Circuit ]

First, an example of the structure of an engine cooling circuit to which the thermostat device of the present embodiment is applied will be described with reference to fig. 1. 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 of cooling water for cooling the engine U2. The engine cooling circuit U of the present embodiment circulates cooling water through 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 (Exhaust Gas Recirculation) cooler U7.

Specifically, the engine cooling circuit U of the present embodiment has a feed passage T1, a return passage T2, a first branch passage T3, a second branch passage T4, and a bypass passage Tp 1.

Here, the feed passage T1 connects the cooling water outlet of the radiator U3 to the cooling water inlet of the engine U2, and allows the cooling water cooled by the radiator U3 to flow to the engine U2. The water pump U4 is provided in the feed passage T1, and the water pump U4 applies a thrust force to the coolant so that the coolant 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. Most of the cooling water sent to the engine U2 flows through water jackets formed in the oil cooler U2c, the cylinder block U2b, and the cylinder head U2a, and then flows to the return passage T2.

Further, a part of the cooling water flowing into the cooling water inlet of the engine U2 flows through the water jackets formed in the oil cooler U2c, the cylinder block U2b, and the cylinder head U2a, and then flows into the first branch passage T3. The other part of the coolant flowing into the coolant inlet of the engine U2 branches off from the side of the oil cooler U2c, the cylinder block U2b, and the cylinder head U2a, flows through the second branch passage T4, cools the EGR cooler U7, and then returns to the feed passage T1.

The first branch passage T3 sends a part of the cooling water having absorbed heat in the engine U2 to the feed passage T1 after passing through the heat exchangers of the air conditioning heater U5 and the transmission heater U6, respectively. At this time, the heat exchanger of the air conditioner heater U5 warms the air to be sent to the vehicle interior by the heat obtained from the cooling water. 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 to the cooling water inlet of the radiator U3, and allows the cooling water that has absorbed heat in 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 coolant fed from the engine U2 to the return passage T2 is controlled by the thermostat device U1.

Specifically, the thermostat device U1 causes the cooling water sent from the engine U2 to the return passage T2 to flow to one of the radiator U3 and the bypass passage Tp1 (described later with reference to fig. 2) by control of its own valve body.

When the temperature of the coolant exceeds the valve opening reference temperature, the thermostat device U1 causes the coolant sent from the engine U2 to the return passage T2 to flow 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 causes the cooling water sent from the engine U2 to the return passage T2 to flow through the bypass passage Tp1, and to return to the feed passage T1 while bypassing the radiator U3.

The bypass passage Tp1 is provided so as to branch from the middle of the return passage T2, and the cooling water flowing from the engine U2 to the radiator U3 is sent to the feed passage T1 by bypassing the radiator U3, and is 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 structure of the thermostat device U1 according to the present embodiment will be described with reference to fig. 2 to 4. The thermostat device U1 of the present embodiment is, for example, a wax-type thermostat device.

Fig. 2 is a diagram showing a structure of a thermostat device U1 according to the present embodiment. In the following description, in order to clarify the positional relationship of the respective configurations, the flow direction of the cooling water flowing through the passage hole 1M of the thermostat device U1 is referred to as the "downstream side" (the upward direction in fig. 2), and the direction opposite to the flow direction of the cooling water is referred to as the "upstream side" (the downward direction in fig. 2).

The thermostat device U1 includes a case 1, a thermal actuator 2, a valve body 3, a frame 4, a spring 5, a leak passage 6, and a relief valve 7.

The housing 1 is disposed in a 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 1 c.

Here, the input port 1a receives the cooling water sent from the cooling water outlet of the engine U2. The passage hole 1M allows the cooling water received by the input port 1a to flow therethrough. 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. The branch port 1c (the "branch port for bypass" in the present invention) constitutes a part of the bypass passage Tp1, is provided on the upstream side of the valve element 3 so as to branch from the passage hole 1M, and sends the cooling water flowing through the passage hole 1M to the bypass passage Tp 1.

The thermal element 2 is supported in the passage hole 1M so as to be movable in the extending direction of the passage hole 1M. Here, the thermal actuator 2 is supported by a frame 4 fixed to an inner wall of the casing 1.

The thermal actuator 2 includes, for example, a temperature sensing case 2a containing wax and a piston pin 2b, and moves to an upstream side or a downstream side in accordance with expansion or compression of the wax in the temperature sensing case 2 a. Here, the temperature sensing case 2a is disposed upstream of the valve element 3. The piston pin 2b projects downstream from the temperature sensing case 2a and is disposed such that the tip thereof abuts against the frame 4.

The thermal actuator 2 keeps the piston pin 2b in a contracted state when the temperature of the coolant is low, for example, and expands the piston pin 2b toward the downstream side in accordance with the temperature increase of the coolant. Thereby, the thermal actuator 2 (the temperature sensing case 2a) moves in a direction (here, the upstream side) opposite to the direction in which the front end of the piston pin 2b is expanded by the reaction force from the frame 4.

The frame 4 extends in the direction in which the passage hole 1M extends, and a flange portion 4a of the frame 4 is fixed to the inner wall of the housing 1. The frame 4 supports the thermal element 2 in such a manner that the thermal element 2 can move to the upstream side or the downstream side, and supports one end of the spring 5 on the upstream side of the thermal element 2.

The spring 5 is disposed between the valve body 3 and the frame 4, and biases the valve body 3 toward the flange portion 4 a.

The valve body 3 is engaged with the thermal actuator 2 in the passage hole 1M, and opens or closes the passage hole 1M in response to movement of the thermal actuator 2 toward the upstream side or the downstream side in the extending direction of the passage hole 1M.

More specifically, the valve body 3 is joined to the thermal actuator 2 so as to be located in the vicinity of an opening of a flange portion 4a of a frame 4 fixed to an inner wall of the housing 1. The valve body 3 is disposed in a state of being biased toward the side (here, the downstream side) that closes the opening of the flange portion 4a by a spring 5, and the spring 5 is interposed between the valve body 3 and the frame 4. The valve body 3 closes the opening of the flange portion 4a by the biasing force of the spring 5 in a state where the thermal actuator 2 is contracted, thereby closing the passage hole 1M. When the thermal actuator 2 is expanded, the valve element 3 moves to the side where the opening of the flange portion 4a is opened against the biasing force of the spring 5 due to the expansion force of the thermal actuator 2, thereby opening the passage hole 1M.

The leak passage 6 is formed in the housing 1 such 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 leakage path 6 prevents all of the cooling water flowing into the input port 1a from flowing through the bypass path T1p when the thermostat device U1 is closed, and allows a part of the cooling water flowing into the input port 1a to flow to the output port 1c through the leakage path 6. Thus, even when the thermostat device U1 is closed, the cooling water can be circulated around the temperature sensitive case 2a via the leakage path 6.

The relief valve 7 switches between an open state and a closed state of the leak passage 6 in accordance with the state of the cooling water in the engine cooling circuit U. Typically, the pressure relief valve 7 acts in the following way: when the coolant in the engine U2 is in a low temperature state, the leak path 6 is closed, and when the temperature of the coolant is close to the valve opening reference temperature or when the temperature of the coolant is estimated to be close to the valve opening reference temperature, the leak path 6 is opened.

The relief valve 7 is, for example, a pressure-actuated valve that operates to open or close the leak passage 6 in accordance with the pressure of the cooling water flowing on the upstream side of the valve body 3 (see fig. 3). The pressure release valve 7 includes, for example: a ball 7a provided in the leak passage 6; and an urging spring 7b for urging the ball 7 a. In fig. 3, the leak passage 6 communicates with a valve arrangement space 6a extending upward from the leak passage 6, and the ball 7a and the biasing spring 7b are arranged in the valve arrangement space 6 a.

The ball 7a is configured to have a diameter substantially equal to the diameter of the leak passage 6, for example, and to be able to close the leak passage 6. The ball 7a is disposed in a boundary region between the valve disposition space 6a and the leak path 6 so as to be able to enter the leak path 6 and to be able to retreat into the valve disposition space 6 a. The biasing spring 7b has one end connected to the ball 7a and the other end connected to the upper end of the valve arrangement space 6a, and biases the ball 7a downward.

With such a configuration, when the pressure of the cooling water flowing on the upstream side of the valve body 3 is low, the relief valve 7 is configured such that the ball 7a enters the leakage passage 6 side by the biasing force of the biasing spring 7b, and closes the leakage passage 6. When the pressure of the cooling water flowing on the upstream side of the valve element 3 becomes high, the ball 7a is retracted into the valve arrangement space 6a against the biasing force of the biasing spring 7b, and the leak passage 6 is opened.

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 the engine load, for example, and makes the pump output small when the engine load is small and large when the engine load is large. In other words, in the case where the engine load increases, the water pump U4 increases the pump output so that the amount of heat radiation that radiates heat via the cooling water in the radiator U3 increases. Further, the pressure of the cooling water flowing through the engine cooling circuit U increases in accordance with an increase in the pump output of the water pump U4. The water pump U4 detects that the engine U2 is in a high-load operation by obtaining engine output information from, for example, an Electronic Control Unit (ECU) (not shown) of the vehicle.

That is, the relief valve 7 operates as follows: when the engine load increases and the cooling water temperature tends to increase, the leak passage 6 is opened when the pump output of the water pump U4 increases. Thus, the relief valve 7 opens the leak passage 6 before the cooling water temperature reaches the valve opening reference temperature. Thereby, a flow circulating around the temperature sensitive housing 2a is generated via the leakage path 6.

Here, the operation of the thermostat device U1 of the present embodiment will be described with reference to fig. 4.

Fig. 4 is a diagram showing an example of changes in 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, a variation until the thermostat device U1 is opened when the vehicle is loaded and the vehicle is operating at a high load.

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

Therefore, at this time, all the cooling water flowing into the input port 1a of the thermostat device U1 is not sent to the radiator U3 side, but flows to the bypass passage Tp1 via the branch port 1 c.

When the engine U2 is in a high-load operation state (at timing T1) due to loading of cargo or the like in the vehicle, the cooling water absorbs heat from the engine U2 and starts to increase in temperature.

Also, in the case where the engine U2 becomes a high load operation, the water pump U4 increases the pump output (timing T2). Since the water pump U4 increases the pump output, the pressure of the cooling water circulating in the engine cooling circuit U also increases. Then, the relief valve 7 opens the leak passage 6 due to the increase in pressure.

Thus, before the temperature of the coolant circulating in the engine cooling circuit U rises to the valve opening reference temperature, a part of the coolant flowing into the input port 1a starts to flow to the output port 1b via the leakage passage 6. At this time, the cooling water flowing to the output port 1b side through the leakage passage 6 also flows around the vicinity of the temperature sensing case 2a of the heat actuator 2, and the amount of heat received in the temperature sensing case 2a also increases.

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 accordingly (timing T3). Thereby, the thermostat device U1 moves the valve body 3 to open the passage hole 1M. Thus, when the temperature of the cooling water has increased, the cooling water flowing into the input port 1a of the thermostat device U1 is sent to the radiator U3 via the output port 1b, and is cooled.

In this way, the thermostat device U1 controls the circulation path of the coolant in the engine cooling circuit U, and when the temperature of the coolant in the engine U2 is low, the coolant is quickly increased in temperature, and when the temperature of the coolant in the engine U2 has increased to the valve opening reference temperature, the temperature of the coolant is decreased by the radiator U3.

[ Effect ]

As described above, the thermostat device U1 of the present embodiment includes the leakage passage 6 and the relief valve 7, one end of the leakage passage 6 communicates with the passage hole 1M on the upstream side of the valve body 3, the other end communicates with the passage hole 1M on the downstream side of the valve body 3, and the relief valve 7 switches the open state and the closed state of the leakage passage 6 in accordance with the state of the cooling water.

Therefore, according to the thermostat device U1 of the present embodiment, when the temperature of the coolant in the engine U2 is low, the leak passage 6 can be closed, and the coolant can be prevented from flowing into the radiator U3. When it is estimated that the temperature of the cooling water is close to the valve opening reference temperature, the leakage path 6 can be opened, and the cooling water can be circulated around the temperature sensitive case 2a through the leakage path 6.

This can promote the temperature rise of the cooling water in the engine U2 from the low temperature state, and improve the thermal responsiveness to the temperature change of the cooling water. That is, this can suppress the 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 configured by a pressure-actuated valve, it can be reliably operated (i.e., opened) before the temperature of the cooling water rises to the valve-opening reference temperature.

(other embodiments)

The present invention is not limited to the above embodiments, and various modifications are conceivable.

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

In the above embodiment, the relief valve 7 is configured by a pressure-actuated valve as an example of the thermostat device U1. However, instead, it may be constituted by a relief valve 7 of a thermally actuated valve. However, in the case where the relief valve 7 is formed by a thermally actuated valve, the thermal valve 7 is preferably formed by a pressure actuated valve because a problem of thermal responsiveness occurs similarly to the thermal valve unit 2 of the thermostat device U1.

In the above embodiment, the pump output of the water pump U4 is controlled based on the engine load as an example. However, the water pump U4 may control its pump output by referring to the elapsed time from the start of the engine, the cooling water temperature, and the like instead of the engine load, or by referring to the elapsed time from the start of the engine, the cooling water temperature, and the like in addition to the engine load.

In the above-described embodiment, the vehicle is shown as an example of the object to which the thermostat device U1 is applied, but the object to which the thermostat device U1 is applied is not limited to this. For example, the thermostat device U1 may also be applied to a generator, a construction machine, a ship, and the like.

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

The present application is based on the japanese patent application (japanese patent application 2019-180338) filed on 30.9.2019, the contents of which are hereby incorporated by reference.

Industrial applicability

Description of the reference numerals

1 outer cover

1M via hole

1a input port

1b output port

1c Branch Port

2 thermal power part

2a temperature sensing shell

2b piston pin

3 valve body

4 frame

4a flange part

5 spring

6 leakage path

7 pressure release 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 path

T2 return path

T3 first shunt

T4 second branch path

Tp1 bypass path

Claims

1. A thermostat device is characterized by comprising:

a passage hole for allowing cooling water to flow to the radiator;

a bypass branch port that branches from the passage hole;

2. A thermostat device that is disposed in an engine cooling circuit and controls a circulation path of cooling water flowing from an engine to a radiator, the thermostat device comprising:

a housing including a passage hole through which the cooling water flows, and an input port, an output port, and a branch port for bypass, which communicate with the passage hole;

3. The thermostat device of claim 2,

the relief valve is a pressure-actuated valve that operates to switch between an open state and a closed state of the leakage passage in accordance with the pressure of the cooling water flowing on the upstream side of the valve body.

4. The thermostat device of claim 3,

the one end of the leakage passage communicates with the passage hole at a position located on an upstream side of the valve body and on a downstream side of the temperature sensing unit of the thermal actuator.

5. The thermostat device of claim 2,

when the cooling water increases in temperature from a low temperature state, the relief valve opens the leakage passage at a timing earlier than a timing at which the valve body opens the passage hole.