The invention relates a thermostat assembly providing controlled progressivity in the opening of radiator window.

Specifically, the present invention relates to a valve structure having undulated valve element allowing controlled coolant flow between radiator and thermostat interior space.

Prior Art

Thermostat assembly within engine cooling system provides proper cooling of the engine and its parts by determining the flow ratio between bypass circuitry and heat exchange circuity according to the actual temperature value of engine coolant. The change in the flow ratio between bypass circuitry and heat exchange circuity is possible with the change in the opening ratio between bypass inlet window and radiator inlet window or bypass outlet window and radiator outlet window. The change in the opening ratio is provided by the forward and backward motion of the valve structure guided by means of an actuator throughout thermostat interior space.

When the temperature value of the coolant coming from engine outlet is below than a first threshold value, the coolant continues to flow from bypass inlet to outlet throughout bypass circuitry comprising engine channels, water pump and thermostat assembly. At this temperature values below than the first threshold value, the actuator continues to be stay at fully closed position, consequently the valve structure too. At this fully closed position of the actuator, valve structure allows coolant flow from bypass inlet to outlet and prevents coolant flow from radiator inlet to outlet by closing upper valve seat via upper valve element.

When the piston starts to move forward as a result of the increase in the coolant temperature (exceeding the first threshold value), other portion of the actuator (actuator body) starts to move backward due to the piston seat that restricts the forward motion of the piston end. The backward motion of the actuator body causes the backward motion of the valve structure too thanks to the force applied on sleeve seat of valve structure by sleeve portion of the actuator. During backward motion of the valve structure, spring element is compressed. So, the spring stores potential energy. At this partially open position of the actuator, valve structure allows coolant coming from both bypass inlet and radiator inlet to flow toward outlet. When the temperature value of the coolant coming from engine outlet is equal or above than a second threshold value, opening of the actuator reaches its maximum point (full backward motion), consequently opening of the valve structure too. At this fully open position of the actuator, valve structure allows coolant coming from radiator inlet to flow toward outlet and prevents coolant flow from bypass inlet to outlet by closing the lower valve seat via lower valve element. At this temperature values above than the second threshold, the coolant coming from engine outlet continues to flow from radiator inlet to outlet throughout heat exchange circuitry comprising engine channels, radiator channels, water pump and thermostat assembly.

In the conventional thermostat assemblies, during passing from fully closed position to partially open position or partially open position to fully open position, there is not any variable except the stroke value of the actuator for determining the amount of the coolant that flows from the radiator channel to thermostat interior space. This means that the amount of the coolant flowing from radiator inlet to outlet throughout thermostat interior space depends on just the size of opening (gap) between upper valve seat and upper valve element. The opening is determined by just the stroke value provided by the actuator. However, since the amount of opening is generally more than the required opening, the cooling is more than the required cooling. So, it is not possible to reach desired cooling target at once. The valve structure has to change position forwards and backwards until reaching the desired cooling target.

The document EP2246599A1 mentions a control valve for a fluid flow circuit. There is a lateral opening permitting to control the progression of fluid flow. However, here it is not mentioned about a valve structure having undulated wall structure on the top surface of its upper valve element.

As a result, there is a require for a thermostat assembly allowing to reach the desired cooling target at once by providing controlled coolant flow from radiator inlet to outlet.

Objectives and Short Description of the Invention

The aim of the present invention is to present a thermostat assembly allowing to reach the desired cooling target at once by providing controlled coolant flow from radiator inlet to outlet.

The another aim of the present invention is to present a valve structure allowing controlled coolant flow from radiator inlet to outlet by restricting the opening between upper valve seat and upper valve element via its undulated wall structure.

Present thermostat assembly comprises - an upper frame including an upper valve seat,

- a valve structure including an upper valve element,

- an undulated wall structure formed on the top surface of mentioned upper valve element.

Mentioned undulated wall structure has at least one crest and related one trough.

In the preferred embodiment of the invention, mentioned undulated wall structure could have more than one crests and related troughs.

Lowest point of each trough could be designed as different to each other according to the cooling requirement of the cooling system.

Highest point of each crest could be designed as different to each other according to the cooling requirement of the cooling system.

Dimensions of each crest and of trough could be designed independent to each other according to the cooling requirement of the cooling system.

In the other preferred embodiments of the present invention, mentioned upper valve seat has an undulated form.

Description of the Figures

In figure 1 , a perspective view of the present valve structure is given.

In figure 2a, a top view of the mentioned valve structure is shown.

In figure 2b, a cross-sectional view of the said valve structure is shown.

In figure 2c, a perspective view of another embodiment of the present valve structure is given.

In figure 2d, a cross-sectional view of mentioned embodiment of the present valve structure is given.

In figure 3, a cross-sectional view of the present thermostat assembly in fully closed position is given.

In figure 4, a cross-sectional view of the mentioned thermostat assembly in partially open position is given.

In figure 5, a cross-sectional view of the said thermostat assembly in fully open position is given.

In figure 6, an exploded perspective view of the present thermostat assembly is shown.

In figure 7a, a perspective view of conventional valve structure is given. In figure 7b, a cross-sectional view of the conventional valve structure is given.

In figure 8, a cross-sectional view of the conventional thermostat assembly in fully closed position is given.

In figure 9, a cross-sectional view of mentioned conventional thermostat assembly in partially open position is given.

In figure 10, a cross-sectional view of said conventional thermostat assembly in fully open position is given.

In figure 1 1a, a close cross-sectional view of the present thermostat assembly in the fully closed position is given. (11.2 upper valve seat)

In figure 11 b, a close cross-sectional view of conventional thermostat assembly in the fully closed position is given.

In figure 12a, a close cross-sectional view of mentioned present thermostat assembly in the partially open position where actuator has 1 mm stroke value is given.

In figure 12b, a close cross-sectional view of mentioned conventional thermostat assembly in the partially open position where actuator has 1 mm stroke value is given.

In figure 13a, a close cross-sectional view of said present thermostat assembly in the partially open position where actuator has 2 mm stroke value is given.

In figure 13b, a close cross-sectional view of said conventional thermostat assembly in the partially open position where actuator has 2 mm stroke value is given.

In figure 14a, a close cross-sectional view of the present thermostat assembly in the partially open position where actuator has 3 mm stroke value is given.

In figure 14b, a close cross-sectional view of the conventional thermostat assembly in the partially open position where actuator has 3 mm stroke value is given.

In figure 15a, a close cross-sectional view of the present thermostat assembly in the fully open position where actuator has 4 mm stroke value is given.

In figure 15b, a close cross-sectional view of the conventional thermostat assembly in the fully open position where actuator has 4 mm stroke value is given In figure 16a, progressivity graph of the present thermostat assembly is given In figure 16b, progressivity graph of the conventional thermostat assembly is given.

Reference Numbers

10. Thermostat assembly

10.1. Thermostat interior space

11. Upper frame

11.1. Piston seat

11.2. Upper valve seat

12. Lower frame

12.1. Lower valve seat

14. First spring element

15. Valve structure

15.1. Upper valve element

15.2. Undulated wall structure

15.3. Lower valve element

15.4. Sealing groove

15.5. Sleeve seat

16. Sealing element

17. Guide element

18. Second spring element

30. Actuator

30.1. Sleeve

30.2. Piston

A. Progressivity line of present thermostat assembly

B. Progressivity line of conventional thermostat assembly

C. Crest

T. Trough

Detailed Description of the Invention

This invention relates to a thermostat assembly (10) which provides controlled coolant flow between radiator inlet and thermostat interior space (10.1) via valve structure (15) having undulated valve element restricting amount of coolant flow therefor. In the conventional thermostat assemblies, during passing from fully closed valve position to partially open position or from partially open position to fully open position, the amount of the coolant flowing from the opening between the valve seat and valve element cannot be controlled by the other variant except the stroke value of the actuator. Since the amount of opening versus the unit stroke value is greater than the required amount, this causes a sudden decrease in the temperature value of the engine coolant. Then, the valve moves forward for decreasing amount of the coolant coming from radiator inlet and consequently for increasing the amount of the coolant coming from the bypass inlet. However, this time, the amount of closing versus the unit stroke value is greater than the required amount, so this causes a sudden increase in the temperature value of the engine coolant. Then, the valve moves backward for increasing amount of the coolant coming from radiator inlet and consequently for decreasing the amount of the coolant coming from the bypass inlet. However, this time, the amount of opening versus the unit stroke value is again greater than the required amount, so this causes a sudden decrease in the temperature value of the engine coolant. This forward and backward motions of the valve structure continue until reaching desired cooling target. Since the opening or closing amount versus unit stroke of the actuator is greater than the required one, it takes time to reach the desired cooling target. Here, it is not possible to reach the target at once. The table showing the clearance and opening values versus each stroke for conventional valve structure is given below. Here, clearance is the perpendicular distance between upper valve element and upper valve seat.

The present invention allows the desired cooling target to be reached at once without unnecessary forward and backward motions of the valve structure (15). This is possible thanks to the valve structure (15) having an upper valve element (15.1) with undulated wall structure (15.2).

As shown in Figure 6, the present thermostat assembly (10) comprises an upper frame (1 1) which includes an upper valve seat (11.2) located on its lower surface and a piston seat (11.1) formed inside as coinciding to the center of the mentioned upper valve seat (11.2),

an actuator (30) including a sleeve (30.1) and a piston (30.2), a valve structure (15) which includes an upper valve element (15.1) with an undulated wall structure (15.2) and a lower valve element (15.3) with a sealing groove (15.4),

a first spring element (14) which is located between mentioned upper valve element (15.1) and lower valve element (15.3),

a sealing element (16) which is located within mentioned sealing groove (15.4) on the lower valve element (15.3),

a lower frame (12),

a guide element (17) which is located between lower valve element (15.3) and mentioned lower frame (12),

a second spring element (18) which is located between mentioned guide element (17) and said lower frame (12).

Present thermostat assembly (10) provides controlled coolant flow between radiator inlet and outlet, versus unit stroke value of the actuator (30) thanks to the undulated wall structure (15.2) formed on the top surface of the upper valve element (15.1). The undulated wall structure (15.2) could have one or more crests (C) and troughs (T) according to the cooling control requirement of the cooling system. In another embodiment of the invention, the upper frame (1 1) has an undulated wall form instead of the undulated wall structure (15.2) of the upper valve element

(15.1). The undulated wall form could have one or more crests and troughs according to the cooling control requirement of the cooling system. And also, the geometries and dimensions of each crest (C) and related trough (T) can vary according to the requirements. A perspective view of the valve structure (15) having an upper valve element (15.1) with an undulated wall structure

(15.2) is given in Figure 1. As seen from the Figure 1 , in this embodiment of the invention, the lowest level of each trough (T) is different to each other. So, the opening amount corresponding to the unit stroke value could be chanced according to the cooling requirement by designing the troughs (T) in different levels and dimensions. During passing from fully closed position to partially open position, the coolant within the radiator channel flows firstly throughout the trough (T) that is located at the lowest level. Then, with the backward advance of the valve structure (15), the coolant continues to flow respectively throughout the other troughs (T) according to their levels. Thus, unlike the conventional valve structures, the present valve structure (15) provides controlled flow of the coolant within the radiator channel towards thermostat interior space (10.1). Thanks to the controlled coolant flow, there is not any sudden decrease or increase in the temperature of the engine coolant circulating throughout engine channel. So, it is possible to reach the desired cooling target at once without any unnecessary forward and backward motions of the valve structure (15). The table showing the clearance and opening values versus each stroke for present valve structure (15) is given below. Here, clearance is the perpendicular distance between upper valve element (15.1) and upper valve seat (11.2).

Besides, all above properties given according to the thermostat assembly (10) having two inlets- one outlet can be also applicable for the thermostat assembly (10) having one inlet-two outlets.

Present valve structure’s (15) a top view showing mentioned undulated wall structure (15.2) is given in Figure 2a. A cross-sectional view of the present valve structure (15) is given in Figure 2b. From this figure, it is possible to see that the levels of two consecutive (or each) troughs (T) are different to each other while level of each crest (C) is equal to each other. This provides the controlled coolant flow at changing ratios according to the design of the valve structure (15) versus each advance in the stroke value of the actuator (30).

Perspective and cross-sectional views of another preferred embodiment of the present valve structure (15) are given respectively in Figure 2c and 2d. Here, level of each crest (C) is different to each other while level of each trough (T) is equal to each other.

A cross-sectional view of the present thermostat assembly (10) in the fully closed position is given in Figure 3. As seen from this figure, since the upper valve seat (11.2) is closed by the upper valve element (15.1), at this fully closed thermostat position the coolant within the radiator channel cannot flow towards the thermostat interior space (10.1). Here, coolant flows throughout just the bypass circuitry.

A cross-sectional view of the present thermostat assembly (10) in the partially open position is given in Figure 4. As a result of the backward motion of the valve structure (15), the upper valve element (15.1) also moves backward. As seen from this figure, there is opening only between the trough (T) portion of the upper valve element (15.1) and the upper valve seat (11.2). The crest (C) portion of the upper valve element (15.1) continues to be in contact with the upper valve seat (1 1.2). So, at this position of the present thermostat assembly (10), the coolant within the radiator channel flows through between the upper valve seat (1 1.2) and the troughs (T) that do not be in contact with the upper valve seat (11.2). By designing the level of each trough (T) as being different to each other, it is possible to control amount of the coolant flow corresponding to unit stroke value of the actuator (30).

A cross-sectional view of the present thermostat assembly (10) in the fully open position is given in Figure 5. As seen from this figure, since the lower valve seat (12.1 ) is closed by the lower valve element (15.3), at this fully open thermostat position the coolant within the bypass channel cannot flow towards the thermostat interior space (10.1). Here, coolant flows throughout just the heat exchange circuitry.

An exploded perspective view of the present thermostat assembly (10) is given in Figure 6. Here, it is possible to see easily the undulated wall structure (15.2) of the upper valve element (15.1).

Perspective and cross-sectional views of the conventional valve structure are given respectively in Figure 7a and 7b.

A cross-sectional view of the conventional thermostat assembly in the fully closed position is given in Figure 8. A cross-sectional view of the conventional thermostat assembly in the partially open position is given in Figure 9. As seen from this figure, since there is not any undulated structure on the upper valve element, here, the opening between the upper valve seat and the upper valve element is equal everywhere. So, it is not possible to control amount of the coolant flow corresponding to unit stroke value of the actuator (30). A cross-sectional view of the conventional thermostat assembly in fully open position is given in Figure 10.

Close cross-sectional views of present and conventional thermostat assemblies in the fully closed position are given respectively in Figure 1 1a and 1 1 b.

Close cross-sectional views of present and conventional thermostat assemblies in the partially open position wherein thermo element has 1 mm stroke value are given respectively in Figure 12a and 12b.

Close cross-sectional views of present and conventional thermostat assemblies in the partially open position wherein thermo element has 2 mm stroke value are given respectively in Figure 13a and 13b.

Close cross-sectional views of present and conventional thermostat assemblies in the partially open position wherein thermo element has 3 mm stroke value are given respectively in Figure 14a and 14b. Close cross-sectional views of present and conventional thermostat assemblies in the fully open position wherein thermo element has 4 mm stroke value are given respectively in Figure 15a and 15b.

Progressivity line of present thermostat assembly (A) and the progressivity line of conventional thermostat assembly (B) are shown respectively in the graphs given in Figure 16a and 16b.