A THERMOSTAT ASSEMBLY FOR INTERNAL COMBUSTION

ENGINES

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.

Internal combustion engine thermostats carry on this duty by closing and opening their valve on coolant flow passage from engine block to radiator; according to they are adjusted temperature to open or to close. They are adjusted for efficient engine temperature range. In case of higher temperature than the efficient engine temperature, thermostatic valve opens the flow to radiator for cooling of the coolant. On the lower temperature conditions, thermostatic valve stays at close position.

Wax type thermostats are most common solution on today's engines to keep the engine in proper temperature range. Their working method bases an expandable 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 temperatures, this mechanism is called as thermo-actuator. They adjusted to efficient engine temperature range by using proper wax compound, which its expansion temperature matches with the engine efficient temperature. This expansion cause opening of a valve for cold coolant by a mechanism, which varies according the thermostat design. Wax type thermostats constructions may vary.

In our invention is an alternative thermostat assembly that comprises a typical wax actuator, a valve, a seal on the valve where valve seat on the housing to close coolant flow to radiator, a spring, which forces valve for closing when the coolant temperature drops down, a frame, which valve guided inside it.

Description of the Figures:

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

Figure 1 Exploded view of the thermostat assembly.

Figure 2 3D view of the thermostat assembly

Figure 3 Cross-section view of the thermostat assembly

Figure 4 Cross-section view of the thermostat assembly without Thermo-actuator

Figure 5 An application example of the thermostat assembly on engine circulation system

Description of the References:

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

2 Seal

3 Valve

4 Seal groove

5 Valve arms

6 Valve Claws

' 7 Spring

8 By-pass barrier of frame

9 Frame

10 Frame Claws

1 1 Semicircle shaped passages 12 Runners (on Frame)

13 Internal claws (for thermo-actuator fitting)

14 Housing

15 Cover

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, generates a linear movement on thermo-actuator' s (1) piston, which its top is placed on housing (14). Thermo-actuator (1) is fitted among internal claws (13) inside the valve (3), so that they move together (Figure 3 - Figure4). Press fitting of the thermo-actuator (1) among internal claws (13) strengthens the valve arms (5) and obstructs the stretching of them, to avoid disassembling of valve(5) from frame (9), which valve (3) is assembled by valve claws (6) inside the runners (12) of the frame (9). Movement of the Thermo- actuator (1) opens or closes the valve (3). There is a sealing (2) that placed on a groove (4) on the valve (3), to obstruct the coolant flow from engine block to radiator between valve (3) and housing (14), when valve (3) is in closed position.

Valve claws (6) are guided inside the frame (9) by runners (12) on inner surface of the cylindrical shaped frame (9). Valve (3) makes its linear movement with thermo-actuator (1) by valve arms (5) inside the frame (9). Piston of the thermo-actuator (1) is placed on the housing (14) and flange side of the frame (9) is placed on housing (14) by frame claws (10) placed in the channels on the housing (14) (Figure 5). These frame claws (10) hold the thermostat stable inside the housing (14) and do not reflect the spring (7) force on the cover (15). Outer skirts of the frame (9) is placed on the housing (14) and ensure the sealing between housing (14) and frame (9).

Rising coolant temperature reflect to wax compound inside the thermo-actuator (1), expansion of the wax compound inside the thermo-actuator moves piston and it opens the valve (3). By opening of the valve (3) from a big cross-section high coolant flow goes to radiator from engine block to reduce the coolant temperature on the radiator. In this position, which called as valve open position, valve arms (5) go down through frame (9) and it is surrounded by the By-pass barrier (8) of the frame (9), so that it obstructs the flow towards to by-pass way on cooling system. There is just a small flow through the semicircle shaped passage (11) on the barrier (8), which ensures the temperature of the coolant around the Thermo-actuator (1) is same with the actual temperature of the coolant on the cooling system. This feature helps thermo-actuator (1) to move correctly according the actual system temperature.

In case of temperature drop on coolant, wax compound losses volume inside the wax capsule and spring (7) force closes the valve (3). Spring (7) is set between the valve (3) and the flange of frame (9).