ELECTRICALLY HEATED MAP CONTROLLED THERMOSTATIC VALVE CONSTRUCTION FOR AN INTERNAL COMBUSTION ENGINE

TECHNICAL FIELD OF INVENTION

This invention relates to an electrically heated and map controlled thermostat,- which has a construction for connecting the leads of electrically heated piston to a power connector socket which does not need to disassemble of wax capsule and electrically heated piston while fixing it into the thermostat housing. PRIOR ART (STATE of THE ART)

On the internal combustion engines with liquid coolant, over heating that occurred by burning of fuel is transferred via coolant. By this way engine can run in proper temperature range. In some cases, engine may reach to different temperatures than the designed temperature range. Due to this reason engine temperature stabilising is an important concern for design studies in order to decrease the harmful gas emission rates.

Wax type thermostat is a solution in order to keep the engine in proper temperature range. Their working method based on an expandable wax compound which is filled in a capsule, sealed from outer environment arid closed with a cover. This subassembly mechanism is called as a Thermal Actuator.

Expansion of the wax constitutes a linear movement. 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 valve has not opened During this response time period engine temperature is higher than proper engine running temperature, engine is forced to run higher temperature conditions, far from it is designed for.

Stabilising and keeping coolant temperature of engine in designed range may not be possible due to response time of wax compound, especially in high load engine running conditions. In order to eliminate response time delays, before engine over heating or low temperature of coolant, wax compound may be heated by an Electrically Heated Piston. When a voltage is applied to Electrically Heated Piston, it heats wax compound by conduction consequently wax compound expands and it forces to open valve in order to cool down the engine temperature.

In the prior art, in order to fix the Thermal Actuator assembly to Thermostat Housing, Thermal Actuator assembly (shown in Fig-3) should be disassembled as shown in Fig-4 and Electrically Heated Piston and remaining sub assembly should be re-assembled through Thermostat Housing for obtaining assembly as shown in Fig-5. Fig-3 shows the initial position of thermal actuator assembly after the production. Fig- 4 shows the separation of Electrically Heated Piston and Wax Capsule then re-assembled into Thermostat Housing as seen in Fig-5. This process is one of the most significant operation in Thermostatic Valve production and may lose its calibration and therefore precision of Thermostatic Valve opening temperature feature. In the present invention, a Thermal Actuator assembly, as shown in Fig-1 and Fig-2, is designed in which construction Thermal Actuator assembly can be fixed to thermostat housing without separation of Wax Capsule and Electrically Heated Piston. By this way lose of calibration risk is avoided.

Description of the Figures: In order to explain the present invention the attached figures have been prepared. Definition of the Figures is given below. Figures are only for example.

Figure 1 Cross-section view that shows details of Thermostatic Valve in the present invention.

Figure 2 Cross-section view that shows details of connection between Power

Connector Socket and Electrically Heated Piston in the present invention.

Figure 3 Cross-section view of Thermal Actuator in the prior art that shows state of an assembly just after the production. Figure 4 Cross-section view of Thermal Actuator in the prior art that shows state of disassembled (electrically heated piston separated from wax capsule) situation just before fixing to the thermostat housing.

Figure 5 Cross-section view of final assembled Map Controlled Thermostat in the prior art. Electrically Heated Piston is re-assembled with wax capsule on Thermostat Housing.

Figure 6 Cross-section view of Thermal Actuator that shows the detail of Electrically

Heated Piston and Wax Capsule assembly in the present invention with plain wire resistance.

Figure 7 Cross-section view of Thermal Actuator that shows the detail of Electrically

Heated Piston and Wax Capsule assembly in the present invention with PTC heating element.

Description of the References:

1 Electrically Heated Piston

2 Wax Capsule

3 Cover

4 Main sealing element

5 Male lead 1

6 Male lead 2

7 Outer sealing element

8 Inner sealing element

9 Fastener- 1

10 Fastener-2

1 1 Power Connector Socket with adaptor female leads

12 Lower Frame

13 Spring

14 Main Valve

15 Wax Compound

16 Thermostat Housing 17 Sealing Element

18 Heater

19 Tube

20 Integrated Power Connection Socket

21 Fastener seal

22 Heater power connection cable

DETAILED EXPLANATION OF THE INVENTION:

Wax compound (15) is filled inside wax capsule (2) and it drives the Electrically Heated Piston (1) with expanding by temperature increase caused by engine coolant temperature or Heater (18). Expansion and shrinkage of wax compound (15) inside the wax capsule (2) generates a linear movement of Electrically Heated Piston (1). Movement of the Electrically Heated Piston (1) opens or closes the main valve (14). An Electrically Heated Piston (1) includes a Heater (18) placed in bottom of tube (19). A Heater (18) may be a plain wire resistance or PTC heating element once energized with electrical current should increase its temperature. A main advantage of PTC heating element with respect to plain wire resistance is its self temperature regulation feature and long term endurance against vibration.

Opening or closing of the main valve (14) is orienting the coolant flow. In case of expansion of wax compound (15), spring (13) is compressed, this occurs on lower frame (12). In case of shrinkage of wax compound (15), spring (13) force pushes the main valve (14) to initial closed position.

Cover (3) fixes and seals the open side of wax capsule (2) besides, keeps Electrically Heated Piston (1) to ensure its axial linear movement. Outer sealing element (7) is used to seal from outer environment, Main sealing element (4) is used to keep the wax compound (2) inside wax capsule (1). Inner sealing element (8) prevents the coolant leakage to outside.

Electrically Heated Piston (1) is placed inside of the wax capsule (2) in order to heat wax compound (15). This subassembly is called Thermal Actuator as shown in Fig-6 should be connected with a separate Power Connector Socket (11) through Thermostat Housing (16) without disassembling of Thermal Actuator assembly ; then it should be tightly fixed with fastener (9 and 10).

Energy is supplied to electrically heated piston (1) through leads (5 and 6) and connection cable (22) via power connector socket (11) for actuation of Thermal Actuator.

In order to fix the thermal actuator to thermostat housing (16), heater (18) is not being disassembled from wax capsule (2). Thermal actuator is fixed with Power Connector Socket (1 1) through Thermostat Housing (16) and tightened via fastener (9).

The present invention which is electrically heated map controlled thermostatic valve construction for an internal combustion engine can be assembled through the thermostat housing without separation of Electrically Heated Piston from the Wax Capsule and allows disassembly of the leads of heating element from power connector socket in order to fix the thermal actuator assembly to thermostat housing without re-calibration requirement and lose of calibration risk comprises the main features with the prior art actuators as below;

Electrically Heated Piston (1),

Wax Capsule (2),

Cover (3),

Main sealing element (4),

Lower Frame (12),

Spring (13),

Main Valve (14),

Wax Compound (15),

Thermostat Housing (16),

Sealing Element (17),

Heater (18)

Tube (19)

Heater power connection cable (22)

Integrated power connection socket (20).

The present invention is characterized in that it comprises; Electrically heated piston (1) comprises male leads (5 and 6),

Power Connector Socket with adaptor female leads (11),

Fasteners (9 and 10)

Outer sealing element (7),

Fastener seal (21)

Inner sealing element (8).