WO2012064293A1

WO2012064293A1 - Quick response time thermostat assembly

Info

Publication number: WO2012064293A1
Application number: PCT/TR2010/000227
Authority: WO
Inventors: Faruk ÜNLÜASLAN
Original assignee: Kirpart Otomotiv Parçalari Sanayi Ve Ticare A.S.
Priority date: 2010-11-08
Filing date: 2010-11-08
Publication date: 2012-05-18
Also published as: DE112010004617T5; CN202883080U; BRPI1005376B1; CN102465753A; BRPI1005376A2; RU129152U1; DE112010004617B4

Abstract

This invention relates to a thermostat assembly for cooling circulation systems of the internal combustion engines, to stabilise the coolant temperature in the range of engine's design, featured with that a passage surrounds the thermo-actuator for coolant flow via a hole on its valve to generate a coolant flow from engine block to radiator. By this way thermo-actuator keeps always same temperature with actual engine coolant temperature.

Description

DESCRIPTION

QUICK RESPONSE TIME THERMOSTAT ASSEMBLY Technological Area:

This invention relates to a thermostat assembly for cooling circulation systems of the internal combustion engines, to stabilise the coolant temperature in the range of engine's design. Known Situation of the Art:

On the Internal Combustion Engines with liquid coolant, over heating that occurred by burning of fuel is transferred via coolant, which is circulated through channels in engine block and cylinder head. By this way engine can run in proper temperature range. Today, decreasing of total emissions of the harmful gases for environment from internal combustion engines is one of the biggest design concerns because of the regulations, which decreases the allowable emissions rate year by year. In the phases that engines run in different temperatures than the designed temperature range, engines release harmful gases in high level emission values. Due to this reason to ensure engine run in proper temperature range, stabilising of coolant temperature and engine temperature helps an efficient fuel burning and decreasing harmful gas emission release. So engine temperature stabilising is an important concern for design studies to decrease the harmful gas emission rates.

Wax type thermostats are most common solution on today's engines to keep the engine in proper temperature range. Their working method bases expansion of wax compound on, by temperature increasing. Wax compound is filled inside a wax capsule and it drives a piston top of the wax capsule expanding by temperature rise, this mechanism is called as thermo-actuator (or wax actuator). This expansion cause opening of a valve, which varies according the thermostat design. Combustion on engine causes over heating on engines and coolant consequently on thermostat. Wax compound, compressed inside a defined volume in thermo-actuator, expands. Expansion of the wax constitutes a linear movement by a piston. Linear movement of piston opens a valve, which oriented the coolant flow towards to radiator to reduce coolant temperature on the system for cooling the engine.

Heat transfer from engine to wax compound through coolant and expansion of the wax compound takes time as called Response Time of Thermostat. During this period engine temperature keeps its increasing trend since thermostatic valve has not opened yet and not let the coolant flow to radiator for cooling. During this response time period engine temperature is higher than proper engine running temperature, fuel combustion efficiency is lower, and engine is forced to run higher temperature conditions, far from it is designed for. End of response time, thermostatic valve let the coolant flow towards to radiator and coolant consequently engine temperature drop to the designated design temperature range. When coolant temperature drops lower than the designated design temperature, thermostatic valve starts to move back closing position because of the wax compound shrinkage after a response time period. Thermostatic valve gets close position and stop the coolant circulation towards to radiator and coolant gets start to warm up. However during this response time period engine temperature is lower than the proper engine running temperature, fuel combustion efficiency is lower, engine is forced to run lower temperature than it is designed.

In case of that coolant flow is not in contact with the wax vessel of thermostatic valve, due to delay of heat transfer, response time of the thermostatic valve takes longer time. Rising temperature heats wax indirectly and lately, consequently thermostatic valve opens late. On contrary situation, while valve is open, in case of the coolant temperature is lower than the efficient engine temperature range: wax temperature drops down lately in same way due to indirect heating transfer. Valve closes lately and it causes lower engine temperature. On this kind constructions keeping and stabilising the engine coolant temperature in the efficient temperature range is not always achieved, due to this indirect heating transfer to wax of the thermostatic valve.

In our invention, for quick heat transfer between the wax and the coolant, there is a coolant passage surrounding wax capsule, and to let the coolant flow through this passage, there is a small hole (approximately 2 mm). By this way coolant flow from the engine block is always in contact with the wax capsule and wax would be exposed same temperature with engine block temperature. It ensures that thermostatic valve opening and closing movements happen according the actual engine block temperatures.

Description of the Figures:

This invention is explained by following figures detailed. Figures are only for example. On these figures:

Figure 1 3D view of an assembly model.

Figure 2 Cross-section view of the model (Cross-Section A-A) Figure 3 Over view of the model

Figure 4 Cross-section view of the model (Cross-Section B-B)

Figure 5 An application example of the invention: Closed position of Thermostatic valve

Figure 6 An application example of the invention: Open position of Thermostatic valve Figure 7 Cross-section view (C-C) of the application showing the coolant flow

Figure 8 Cross-section view (D-D) of the application showing the over view of the coolant passage

Description of the References:

1 Thermo-actuator (comprising wax, wax capsule, piston)

2 Sealing

3 Valve

4 Frame

5 Spring

6 Cover

7 Housing

8 Coolant passage

9 Hole Description of Invention:

Wax compound is filled inside wax capsule and it drives a piston top of the wax capsule expanding by temperatures, this mechanism is called as thermo-actuator (1), expansion and shrinkage of wax compound inside the capsule, by temperature change, creates a linear movement on thermo-actuator (1) piston, which its top is placed on housing (7), at vertical axis up or down. Thermo-actuator (1) is fitted among the nails inside flute of the valve (3), so that they move together. Movement of the Thermo-actuator opens or closes the valve (3). There is a sealing (2) on the valve (3), to obstruct the coolant flow from engine block to radiator between valve (3) and housing (7), when valve is closed position (Fig 5).

Valve (3) is guided inside the frame (4) by runners on the frame (4). Valve (3) makes its axial movement with thermo-actuator (1) inside the frame (4). Piston of the thermo- actuator (1) is placed on the housing (7) and frame is placed on cover (6) (Figures 5-6- 7).

On our invention, there is a passage (8) between thermo-actuator (1) and valve (3) for coolant. The holes (9) generate a flow surrounds the thermo-actuator (1) continuously from the engine block to radiator on the engine. Since coolant flow surrounds the thermo-actuator (1), heat transfer is achieved directly to thermo-actuator (1) (figure 7). Rising coolant temperature heats wax compound inside the thermo-actuator (1), expansion of the wax compound inside the thermo-actuator moves piston and it opens the valve (3) without a late response time (figure 6). Opening of valve (3) generates a passage for coolant between valve (3) and housing (7) to radiator from engine block for cooling the coolant at radiator. In case of temperature drop on coolant, wax compound losses volume inside the wax capsule and spring (5) force closes the valve (3).

Claims

Thermostatic valve assembly for the cooling circulation of an internal combustion engine, in which thermo-actuator (1) fitted inside the valve(3), a seal (2) placed on the valve (3), which obstructs the coolant flow from engine block to radiator at the close position of the valve (3), frame (4) placed on the cover (6) and spring (5), which forces valve for closing when the coolant temperature drops down.

Thermostatic valve assembly according to Claim 1, characterized in that a hole (8) on the valve (4) to pass the coolant flow from engine block to radiator and featured with a passage (8) between the thermo-actuator (1) so that the coolant surrounds the thermo-actuator (1) for a direct heat transfer for quick response time.