WO2020060523A2

WO2020060523A2 - A valve structure minimazing force required for valve control and a thermostat assembly therefor

Info

Publication number: WO2020060523A2
Application number: PCT/TR2019/050771
Authority: WO
Inventors: Faruk UNLUASLAN; Hikmet KANBUR
Original assignee: Kirpart Otomotiv Parcalari Sanayi Ve Ticaret A.S
Priority date: 2018-09-18
Filing date: 2019-09-18
Publication date: 2020-03-26
Also published as: TR201813363A1; WO2020060523A3

Abstract

This invention relates to a valve structure (30) which reduces the force required for control of valve structure (30) by allowing equalization of the coolant pressures exerted on valve structure (30) from both bottom and top sides, and a thermostat assembly (1) therefor. Pressure relief between thermostat interior space (15) and pressure balance chamber (14) provided by a pressure balance channel (33) formed throughout said valve structure (30) between said upper valve element (31) in contact with the coolant within the pressure balance chamber (14) and lower valve element (32) in contact with the coolant within the thermostat interior space (15).

Description

A VALVE STRUCTURE MINIMAZING FORCE REQUIRED FOR VALVE CONTROL AND A

THERMOSTAT ASSEMBLY THEREFOR

Technical Field

The invention relates a wax-based thermostat assembly which exhibits valve control with minimum forces thanks to a pressure balance channel formed through valve structure between closed volume located above thermo-actuator and interior space of thermostat body.

Especially, present invention relates to a valve structure reducing the force required to actuate the valve structure for flow control by allowing pressure balance between mentioned closed volume and interior space of thermostat body via mentioned pressure balance channel formed through valve structure, and a thermostat assembly therefor.

Prior Art

In combustion engines, coolant temperature control is a crucial issue for maintaining vehicle performance. Coolant temperature control provides indirectly temperature control of the engine and engine parts within vehicle.

The coolant temperature control is provided by thermostat assembly which is one of the important components of engine cooling systems within vehicles. Thermostat assembly determines coolant flow ratios between radiator outlet and bypass outlet by guiding valve structure via a thermo-actuator through thermostat interior space according to temperature value of inlet coolant coming from engine outlet.

Engineers designs different type, shape and dimension of thermostats according to specifications determined by the vehicles’ design restrictions. Some of the vehicle design requires inlet and outlets to be formed on side wall of thermostat body, so a closed volume is formed above the thermo-actuator as a result of this requirement of these type thermostat designs. Such thermostat assemblies need pipe type valve structures. Although pipe type valve structures have equal surface areas in contact with coolant at both the top and bottom sides, coolant pressure difference between this closed volume and the thermostat interior space allows the magnitude of the force which should be applied by thermo-actuator for actuation of the valve structure to increase. The document US3554440 mentions a solution under title Thermostatic Valve’. Here, a thermostatic valve which has a bimetallic element controlling the flow of fluid between two chambers of valve is presented. There is not any channel structure that would make easier to control of valve structure.

The document US6286534 mentions a solution under title‘Pressure Relief Valve System Including a Pilot Valve Having a Radial Damper Mechanism’. Here, a pilot valve structure which assists the main valve is presented.

As a result, in the prior art, there is a require for a valve structure which eliminates mentioned coolant pressure difference between said closed volume and the thermostat interior space. So that, the solution of the present invention has emerged. However, here, there is not any channel structure that would make easier to control of valve structure, too.

Objectives and Short Description of the Invention

The aim of the present invention is to reduce the force required for motion of the valve structure by providing pressure relief between closed volume and the thermostat interior space via a pressure balance channel formed throughout valve structure.

Another aim of the present invention is to provide pressure balance between coolant pressures within closed volume and thermostat interior space.

The invention is a wax-based thermostat assembly which, comprising a frame including inlet, bypass outlet, radiator outlet portions, a thermo-actuator including heat sensitive reservoir, piston and sleeve portions, a tube type valve structure including upper valve element and lower valve element portions, a spring, a cover including inward recess and spring seat portions, reduces magnitude of force required for control of valve structure by equalizing the coolant pressures exerted on valve structure from both bottom and top sides, and also comprises a pressure balance chamber formed between mentioned upper valve element of mentioned valve structure and frame and,

to allow pressure relief from thermostat interior space towards mentioned pressure balance chamber or vice versa; a pressure balance channel formed throughout said valve structure between said upper valve element in contact with the coolant within the pressure balance chamber and lower valve element in contact with the coolant within the thermostat interior space. Description of the Figures

In figure 1 , a perspective view of the present valve structure which is used within the present thermostat assembly is given.

In figure 2a, top view of the present valve structure is shown. A cross-sectional view (taken from section A-A that is shown in figure 2a) of the present valve structure is given in figure 2b. A side view of the present valve structure is given in figure 2c. A front view the present valve structure is shown in figure 2d.

In figure 3, an exploded perspective view of the present invention is given. As seen this exploded view, the present valve structure is pipe type.

In figure 4a, a perspective view of the present thermostat assembly which comprising mentioned present valve structure is given. In figure 4b, a front view of the present thermostat assembly is shown. In figure 4c, a top view of the present thermostat assembly is given. In figure 4d, a cross- sectional view (taken from section B-B that is shown in figure 4c) of the present thermostat assembly at fully closed position is given.

In figure 5, a cross-sectional view (taken from section A-A that is shown in figure 4c) of the present thermostat assembly at fully closed position is given. As seen this figure, here, the present valve structure allows coolant flow from inlet to just bypass outlet since the coolant temperature is still below the first threshold coolant temperature value.

In figure 6, a cross-sectional view (taken from section B-B that is shown in figure 4c) of the present thermostat assembly at fully open position is given. As seen this figure, here, mentioned present valve structure guided by thermo-element allows coolant flow from inlet to just radiator outlet since the coolant temperature is above the second threshold coolant temperature value.

Reference Numerals

I . Thermostat assembly

10. Frame

I I . Inlet

12. Bypass outlet

13. Radiator outlet

14. Pressure balance chamber

14.1. Piston seat 15. Thermostat interior space

16. Mounting element

20. Thermo-actuator

21. Heat sensitive reservoir

22. Piston

23. Sleeve

25. O-ring

30. Valve structure

31. Upper valve element

31.1. Sleeve seat

31.2. Reservoir nest

32. Lower valve element

32.1. Spring nest

33. Pressure balance channel

33.1. Upper end

33.2. Lower end

34. Upper valve element-closed position

35. Upper valve element-open position

36. Lower valve element-closed position

37. Lower valve element-open position

40. Spring

50. Cover

51. Inward recess

52. Spring seat

Detailed Description of the Invention

This invention relates to a thermostat assembly (1) which reduces force required for control of valve structure (30) by equalizing the coolant pressures exerted on valve structure (30) from both bottom and top sides via a pressure balance channel (33) formed throughout valve structure (30).

The thermostat assembly (1) provides temperature control within engine cooling system by adjusting coolant flow ratio between bypass circuitry and heat exchange circuitry according to the temperature value of coolant incoming from engine outlet. Coolant flow ratio is determined by heat sensitive reservoir (21) portions of thermo-actuators (20) located within thermostat assemblies (10). Heat sensitive reservoir (21) allows the temperature of the engine outlet coolant to be sensed via heat transmission between wax compound and coolant incoming from engine outlet through its reservoir wall. The increase in the wax temperature causes the increase in the wax volume, or vice versa, the decrease in the wax temperature causes the reduce in the wax volume. The volume change in the wax compound allows forward and backward motion of piston (22), consequently forward and backward motion of the valve structure (30) guided by mentioned thermo-actuator (20). Thus, coolant flow control is provided between bypass outlet (12) and radiator outlet (13) according to the valve structure (30) position determined by the temperature of the coolant incoming from engine outlet.

However, in the conventional thermostat assemblies (1), pressure difference occurs between coolant at top side and coolant bottom side of the tube type valve structure (30). The pressure difference occurred between top and bottom sides of valve structure (30) causes increasement in the force required for control of the valve structure (30). Due to dimension restriction of thermostat assemblies (1 ), it is not possible that mentioned additional force required for compensation of mentioned pressure difference is provided by using greater thermo-actuators (20).

The present invention relates to a thermostat assembly (1) comprising a valve structure (30) which provides pressure relief between its top and bottom sides via a pressure balance channel (33) formed through it. So, it is not requiring an additional force for control of the valve structure (30).

The present thermostat assembly (1) comprises a frame (10) including inlet (1 1), bypass outlet (12), radiator outlet (13), pressure balance chamber (14) (closed volume), thermostat interior space (15) and mounting element (16) portions, a thermo-actuator (20) including heat sensitive reservoir (21), piston (22) and sleeve (23) portions, a valve structure (30) including upper valve element (31), lower valve element (32) and pressure balance channel (33) portions, a spring (40), a cover (50) including inward recess (51) and spring seat (52) portions.

Present thermostat assembly (1) provides the force required for control of the valve structure (30) to be reduced by equalizing the coolant pressures exerted on both bottom and top sides of valve structure (30). For equalization of bottom and top side pressures, firstly a pressure balance chamber (14) portion is formed between top side of valve structure (30) and frame (10). Then a pressure balance channel (33) is formed through on the valve structure (30) between mentioned pressure balance chamber (14) and thermostat interior space (15) to allow pressure relief from thermostat interior space (15) towards mentioned pressure balance chamber (14) or vice versa. It could be better to explain the invention through the figures from 1 to 6 for a better understanding.

A perspective view of the present valve structure (30) is given in figure 1. The valve structure (30) comprises an upper valve element (31), a lower valve element (32) and a pressure balance channel (33) formed between mentioned valve elements. Mentioned pressure balance channel (33) formed throughout said valve structure (30) between said upper valve element (31) in contact with the coolant within the pressure balance chamber (14) and lower valve element (32) in contact with the coolant within the thermostat interior space (15). On the upper valve element (31), there are sleeve seat

(31.1) and reservoir nest (31.2) portions formed for the sleeve (23) and heat sensitive reservoir (21) portions of the thermo-actuator (20), respectively. Upper end (33.1) of mentioned pressure balance channel (33) locates on the mentioned sleeve seat (31.1). On the lower valve element (32), there is a spring nest (32.1) portion allowing upper portion of the spring (40) to be located therein. Lower end

(33.2) of said pressure balance channel (33) locates on mentioned spring nest (32.1).

A top view of the present valve structure (30) is given in figure 2a. Mentioned upper end (33.1) of the pressure balance channel (33) which is located on the sleeve seat (31.1) portion of upper valve element (31) is clearly seen from this figure. A cross-sectional view of the present valve structure (30) which is taken from section A-A shown in figure 2a is given in figure 2b. Here, said pressure balance channel (33) which is lying between upper valve element (31) and lower valve element (32) is clearly seen. A side and a front view of the present valve structure (30) are given respectively in figure 2c and 2d.

An exploded perspective view of the present thermostat assembly (1) is shown in figure 3. As understood from this figure, during mounting operation of present thermostat assembly (1), firstly heat sensitive reservoir (21) portion of thermo-actuator (20) is inserted within reservoir nest (31.2) portion formed on upper valve element (31). So, sleeve (23) portion of thermo-actuator (20) locates on sleeve seat (31.1) portion formed on upper valve element (31), too. Then, valve structure (30) comprising thermo-actuator (20) is inserted through frame (10) until piston (22) end of thermo actuator (20) locates within piston seat (14.1) formed on top inner surface of frame (10). Lastly, spring (40) element is inserted between spring nest (32.1) formed on lower valve element (32) and spring seat (52) formed on inner surface of cover (50) via an inward recess (51) structure. So, frame (10) and cover (50) hold all other components of present thermostat assembly (1) between them.

At fully closed thermostat position, mentioned spring (40) element inserted between spring nest (32.1) and spring seat (52) allows the contact position between valve structure (30) and thermo-actuator (20) to be maintained by saving recent position of valve structure (30). So, spring (40) element allows thermostat assembly (1) to be stayed at closed position by applying forward force on lower valve element (32) from bottom side. During position change of thermostat assembly (1) from fully open to fully closed, said spring (40) element allows contact position between valve structure (30) and thermo-actuator (20) to be maintained by moving the valve structure (30) forward. A perspective view, a front view and top view of the present thermostat assembly (1) are given respectively in figure 4a, 4b and 4c.

A cross-sectional view of the present thermostat assembly (1) at fully closed position is given in figure 4d. As seen this figure, here, coolant incoming from engine outlet is allowed to flow throughout bypass circuitry (including inlet (11), bypass outlet (12), engine channels, water pump). This means engine coolant temperature is not high enough to cause said thermo-actuator (20) to start actuation. In other words, engine coolant temperature is still convenient for working condition of engine and engine parts. At this fully closed position of present thermostat assembly (1), upper valve element-closed position (34) allows incoming coolant to flow from inlet (11) to bypass outlet (12) while lower valve element-closed position (36) prevents incoming coolant to flow from inlet (1 1) to radiator outlet (13). Also, here, it is possible to see the pressure balance chamber (14) formed between top side of valve structure (30) and frame (10).

Another cross-sectional view of the present thermostat assembly (1) at fully closed position is given in figure 5. Here, it is possible to see the pressure balance channel (33) formed through present valve structure (30). Mentioned pressure balance channel (14) provides pressure relief between pressure balance chamber (14) and thermostat interior space (15) by connecting them.

A cross-sectional view of the present thermostat assembly (1) at fully open position is given in figure 6. As seen this figure, here, coolant incoming from engine outlet is allowed to flow throughout heat exchange circuitry (including inlet (11), radiator outlet (13), radiator channels, engine channels, water pump). This means engine coolant temperature is high enough to cause thermo-actuator (20) to be fully actuated. In other words, engine coolant temperature is no longer convenient for working condition of engine and engine parts. At this fully open position of present thermostat assembly (1), upper valve element-open position (35) prevents incoming coolant to flow from inlet (1 1) to bypass outlet (12) while lower valve element-open position (37) allows incoming coolant to flow from inlet (1 1) to radiator outlet (13).

Claims

1. The invention is a wax-based thermostat assembly (1) comprising

a frame (10) including inlet (11), bypass outlet (12), radiator outlet (13) portions, a thermo actuator (20) including heat sensitive reservoir (21), piston (22) and sleeve (23) portions; a tube type valve structure (30) including upper valve element (31 ) and lower valve element (32) portions;

a spring (40);

a cover (50) including inward recess (51) and spring seat (52) portions,

characterized in that it also comprising;

a pressure balance chamber (14) formed between mentioned upper valve element (31) of mentioned valve structure (30) and frame (10) and,

a pressure balance channel (33) formed throughout said valve structure (30) between said upper valve element (31) in contact with the coolant within the pressure balance chamber (14) and lower valve element (32) in contact with the coolant within the thermostat interior space (15).

2. A wax-based thermostat assembly (1) according to claim 1 characterized in that mentioned pressure balance channel (33) comprises an upper end (33.1) and a lower end (33.2).

3. A wax-based thermostat assembly (1) according to claim 1 or 2 characterized in that upper valve element (31) comprises a sleeve seat (31.1) and a reservoir nest (31.2).

4. A wax-based thermostat assembly (1) according to claim 3 characterized in that mentioned upper end (33.1) of said pressure balance channel (33) is formed on mentioned sleeve seat

(31.1).

5. A wax-based thermostat assembly (1) according to one of the preceding claims characterized in that lower valve element (32) comprises a spring nest (32.1).

6. A wax-based thermostat assembly (1) according to claim 5 characterized in that mentioned lower end (33.2) of said pressure balance channel (33) is formed on mentioned spring nest

(32.1).