WO2016100670A1

WO2016100670A1 - Thermostat housing configuration

Info

Publication number: WO2016100670A1
Application number: PCT/US2015/066386
Authority: WO
Inventors: Soma POTHURU; Chandrima BHATTACHARYA
Original assignee: Cummins Inc.
Priority date: 2014-12-17
Filing date: 2015-12-17
Publication date: 2016-06-23

Abstract

Thermostat housings, engines, and methods are provided comprising a housing body defining an inlet, an outlet and a valve chamber in flow communication with the inlet and the outlet, and a plurality of thermostat valves disposed in the valve chamber in a configuration relative to a center of the outlet, each valve controlling flow of coolant from the inlet to outlet and including an area and a valve center. The configuration includes placement of each valve such that a line extending between the valve center to the outlet center does not pass through an area of another valve.

Description

THERMOSTAT HOUSING CONFIGURATION

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Application Serial No. 62/093,182, filed on December 17, 2014 the entire disclosure of which is hereby expressly incorporated by reference.

TECHNICAL FIELD

[0002] The present invention relates generally to thermostat housings for engines and more particularly to thermostat valve configurations within a thermostat housing that reduce turbulence and pressure drop across the thermostat housing.

BACKGROUND OF THE DISCLOSURE

[0003] Many engine applications include a thermostat housing having a plurality of thermostat valves that respond to the temperature of coolant of the engine by passing coolant to an engine heat exchanger or radiator when the coolant is too hot or bypassing the radiator when the coolant temperature is below a threshold temperature. The flow of coolant through the housing results in a pressure drop as a result of turbulence or coolant flow interference caused by the thermostat valves. This pressure drop results in a degradation of engine performance as energy is used to force coolant through the housing that could otherwise be used to power the vehicle or other mechanism powered by the engine.

[0004] In prior configurations, the pressure drop problem was addressed by increasing the number of thermostat valves to increase the total flow path through the thermostat housing, and thus to the radiator when the valves were opened. In other prior configurations, the depth of the valve chamber was increased to improve the coolant flow across the thermostat valves by means of increased pressure differential. In either case, the result was increased cost of the thermostat housing. In any event, the placement of the thermostat valves in prior configurations contributed to the increased pressure drop across the thermostat housing because coolant flow across some of the valves interfered with the flow of coolant from other valves to the outlet to the radiator (i.e., caused turbulence in the flow of the coolant).

SUMMARY OF THE DISCLOSURE [0005] According to various embodiments, thermostat housings comprising a housing body defining an inlet, an outlet and a valve chamber in flow communication with the inlet and the outlet, and a plurality of thermostat valves disposed in the valve chamber in a configuration relative to a center of the outlet, each valve controlling flow of coolant from the inlet to the outlet and comprising an area and a valve center, wherein the configuration comprises placement of each valve such that lines extending between each of the valve centers to the outlet center do not pass through an area of another valve are provided.

[0006] Also disclosed are engines comprising an engine block, a heat exchanger, a thermostat housing connected to the heat exchanger and coupled to the engine block, the thermostat housing comprising a housing body defining an inlet, an outlet and a valve chamber in flow communication with the inlet and the outlet, and a plurality of thermostat valves disposed in the valve chamber in a configuration relative to a center of the outlet, each valve controlling flow of coolant from the inlet to the outlet and comprising an area and a valve center, wherein the configuration comprises placement of each valve such that a line extending between a center of the valve to the outlet center does not pass through an area of another valve.

[0007] Also provided are methods of cooling an engine comprising passing coolant through each valve of a plurality of valves of a thermostat housing, comprising a housing body defining an inlet, an outlet and a valve chamber in flow communication with the inlet and the outlet, and a plurality of thermostat valves disposed in the valve chamber in a configuration relative to a center of the outlet, each valve controlling flow of coolant from the inlet to the outlet and comprising an area and a valve center, wherein the configuration comprises placement of each valve such that a line extending between the valve center to the outlet center does not pass through an area of another valve.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Embodiments of the present disclosure will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0009] FIG. 1 is a side view of a prior art thermostat housing;

[0010] FIGs. 2A and 2B are conceptual side views of a prior art thermostat valve in a cold position and a hot position, respectively;

[0011] FIG. 3 is side view of a thermostat housing according to one embodiment of the present disclosure; [0012] FIG. 4 is a conceptual view of an example placement of thermostat valves in a thermostat housing according to the present disclosure; and

[0013] FIG. 5 is another conceptual view of an example placement of thermostat valves in a thermostat housing according to the present disclosure.

[0014] While the disclosure is amenable to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and are described in detail below. The disclosure, however, is not to limit the invention to the particular embodiments described. On the contrary, the invention is intended to cover all modifications, equivalents, and alternatives falling within the scope of the invention as defined by the appended claims.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE DISCLOSURE

[0015] Referring now to FIG. 1, a conventional thermostat housing is shown. Housing

10 includes a housing body 12 which generally defines an inlet 14 (not shown but present on the other side of the reference numeral 14), an outlet 16 and a bypass outlet 18 (also not shown but present on the other side of the reference numeral 18). Housing body 12 forms a flow path from inlet 14, through a valve chamber 20, to either outlet 16 or bypass outlet 18 as is further described below. Valve chamber 20 includes a plurality of thermostat valves 22. As shown, valves 22 are positioned within valve chamber 20 in a rectangular configuration (i.e., on a grid). In other conventional housings, valves 22 may be arranged in valve chamber 20 in a linear configuration. As indicated by arrow 24, the flow of coolant from the center of one or more of valves 22 to outlet 16 is obstructed by one or more of the other valves 22 within valve chamber 20. This type of flow obstruction and increased turbulence contributes to the undesirable increased pressure drop across the thermostat housing mentioned above.

[0016] FIGs. 2A and 2B provide further detail regarding the flow path of coolant through housing 10 and the operation of valves 22. As shown, valve chamber 20 formed in thermostat body 12 includes a lower chamber 26 in flow communication with inlet 14, an intermediate chamber 28 in flow communication with outlet 16, and an upper chamber 30 in flow communication with bypass outlet 18. Lower chamber 26 is separated from intermediate chamber 28 by a first housing wall 32 and intermediate chamber 28 is separated from upper chamber 30 by a second housing wall 34.

[0017] Valve 22 generally includes a base 36, a flange 38, a movable body 40 and an actuator 42. As shown, flange 38 is mounted to first wall 32 and movable body 40 moves relative to second wall 34 in sealing engagement with a seal 44. While valve 22 may be of any of a variety of different configurations, in one embodiment of the present disclosure valve actuator 42 is a charge cylinder containing a wax material (within a capsule) that expands as temperature of the coolant increases and contracts as temperature of the coolant decreases. In other embodiments, valve actuator 42 may be electronically controlled (instead of mechanically controlled).

[0018] Referring now to FIG. 2A, when the engine begins operation, particularly in a low temperature environment, the coolant circulating through the engine does not need to be further cooled by the engine radiator. Accordingly, coolant from the engine that passes through thermostat housing 10 bypasses the radiator and is routed back to the engine. More specifically, coolant passes through housing inlet 14 into lower chamber 26. The coolant then passes through openings (not shown) in flange 38 into movable body 40. From there, the coolant flows through openings (not shown) at the upper end of movable body 40 into upper chamber 30. The coolant is finally routed from upper chamber 30 through bypass outlet 18 back to the engine. The flow path of coolant when thermostat valve 22 is in the cold position depicted in FIG. 2A is represented by arrow 46.

[0019] As the coolant takes the heat rejection from the engine during operation (for example), the coolant increases the temperature of the wax in actuator 42. This causes the wax to expand, which in turn causes actuator 42 to move body 40 upwardly toward the upper wall 48 of housing body 12. In this manner, body 40 moves from a closed position wherein flow to outlet 16 is prevented (FIG. 2 A) toward an opened position wherein flow to outlet 16 (and the radiator) is permitted and flow through bypass outlet 18 directly to the engine is prevented. When body 40 reaches the opened position as shown in FIG. 2B, the coolant passes through housing inlet 14 into lower chamber 26. The coolant then passes through openings (not shown) in flange 38 into movable body 40. From there, as the coolant cannot flow through openings (not shown) at the upper end of movable body 40 because of engagement between the upper end of body 40 and upper wall 48, the coolant flows from intermediate chamber 28 through outlet 16 to the radiator to be cooled. The flow path of coolant when thermostat valve 22 is in the hot position depicted in FIG. 2B is represented by arrow 50.

[0020] Referring now to FIG. 3, one embodiment of a thermostat housing according to the present disclosure is shown. As shown, housing 52 generally includes a housing body 54 which generally defines an inlet 56, an outlet 58 and a bypass outlet 60 (not shown). Housing body 54 forms a flow path from inlet 56, through a valve chamber 62, and to either outlet 58 or bypass outlet 60 (not shown) as is further described below. Valve chamber 62 includes a plurality of thermostat valves 64, 66, 68, 70 which may be the same as the prior art valves 22 described above. As shown, unlike the rectangular configuration of valves 22 in conventional housing 10 (FIG. 1), valves 64, 66, 68, 70 of housing 52 are positioned in a manner that reduces the turbulence of coolant flow from inlet 56 to outlet 58, thereby also reducing the pressure drop across housing 52 compared to that associated with a conventional rectangular configuration of valves 22.

[0021] As best shown in FIG. 4, valve 64 includes an area having a center 72, valve 66 includes an area having a center 74, valve 68 includes an area having a center 76, and valve 70 has an area having a center 78. Outlet 58 also includes an area having a center 80. FIG. 4 depicts imaginary lines extending from the valve centers to center 80 of outlet 58. More specifically, a line 82 extends from valve center 72 to outlet center 80, a line 84 extends from valve center 74 to outlet center 80, a line 86 extends from valve center 78 to outlet center 80, and a line 88 extends from valve center 76 to outlet center 80. According to the principles of the present disclosure, the configuration of valves 64, 66, 68, 70 is such that no line extending from the center of a valve to center 80 of outlet 58 passes through the area of any other valve.

[0022] Additionally, as shown for example for valve 66, tangent lines 90, 92 may be drawn from the perimeter of each valve area to center 80 of outlet 58. According to the principles of the present disclosure, the configuration of valves should be such that any area bounded by the perimeter of a valve area and a tangent line of another valve (such as area 94 of valve 64) will be less than one-half the total valve area. By providing a valve configuration that satisfies the conditions described above (i.e., no center lines pass through other valve areas and no tangent lines encompass one-half or more of the area of another valve), the interference in coolant flow is reduced, which thereby reduces the pressure drop across housing 52 without increasing the number of valves.

[0023] FIG. 5 illustrates a valve configuration in another embodiment of housing 52. In applications where a relatively large number of thermostat valves are required (such as that depicted in FIG. 5), according to the principles of the present disclosure the valves should be arranged such that the valve centers lie on concentric circles centered on the center of outlet 58. As shown, outlet 58 has an area center 96. In this embodiment, two rows of valves are depicted. The outer row includes valves 98, 100, 102, 104. Each of these valves has a valve center that lies on circle 106, which is centered on outlet center 96. The inner row of valves includes valves 108, 110, 112. Each of these valves has a valve center that lies on circle 114, which is also centered on outlet center 96. A line 116 is shown extending from the center of valve 98 to outlet center 96. Similarly, lines 118, 120, 122 are shown extending from valves 100, 102, 104, respectively, to outlet center 96. None of these lines 116, 118, 120, 122 from the outer row of valves 98, 100, 102, 104 pass through the areas of any of the inner row of valves 108, 110, 112. Additionally, as shown for valve 100 as an example, tangent lines 124, 126 from the perimeter of the area of the valve 100 to outlet center 96 bound areas 128, 130 of valves 108, 110, respectively. These areas are less than one-half the total areas of valves 128, 130. In this manner, the configuration of valves reduces coolant flow obstruction and turbulence, which consequently reduces the pressure drop across thermostat housing 52. It should be understood from the foregoing that more than two rows of valves may be provided consistent with the principles of the present disclosure.

[0024] Also disclosed herein are engines and methods of cooling an engine with the thermostat housing according to the various embodiments. Various methods of cooling an engine may comprise controlling flow of coolant through each valve of a plurality of valves of a thermostat housing with the various embodiments of the thermostat housings discussed above.

[0025] Various modifications and additions can be made to the exemplary embodiments discussed without departing from the scope of the present invention. For example, while the embodiments described above refer to particular features, the scope of this invention also includes embodiments having different combinations of features and embodiments that do not include all of the described features. Accordingly, the scope of the present invention is intended to embrace all such alternatives, modifications, and variations in mechanical as well as electronic thermostat housings as fall within the scope of the claims, together with all equivalents thereof.

Claims

CLAIMS: What is claimed is:

1. A thermostat housing, comprising: a housing body defining an inlet, an outlet and a valve chamber in flow

communication with the inlet and the outlet; and a plurality of thermostat valves disposed in the valve chamber in a configuration relative to a center of the outlet, each valve controlling flow of coolant from the inlet to the outlet and comprising an area and a valve center; wherein the configuration comprises placement of each valve such that lines extending between each of the valve centers to the outlet center do not pass through an area of another valve.

2. The thermostat housing of claim 1 , wherein the configuration further comprises placement of each valve such that a tangent line extending between a perimeter of the valve area to the outlet center does not pass through an area of another valve in a manner that, in combination with a perimeter of the other valve area, defines an area of the other valve area that is equal to or greater than one-half the other valve area.

3. The thermostat of claim 1, wherein the housing body forms a flow path from the inlet through the valve chamber.

4. The thermostat housing of claim 1 , further comprising at least seven valves.

5. The thermostat housing of claim 2, further comprising at least seven valves.

6. The thermostat housing of claim 1, wherein the plurality of valves form two rows.

7. The thermostat housing of claim 1, wherein the centers of each of the plurality of valves lie on a circle.

8. The thermostat housing of claim 7, wherein a first plurality of valve centers lie on first circle and a second plurality of valve centers lie on a second circle, the first and second circles being concentric.

9. The thermostat housing of claim 8, wherein the concentric circles are centered on the outlet.

10. The thermostat housing of claim 1 , wherein the plurality of valves form more than two rows.

11. The thermostat housing of claim 1 , further comprising a bypass valve.

12. An engine comprising: an engine block; a heat exchanger; a thermostat housing connected to the heat exchanger and coupled to the engine block, the thermostat housing comprising: a housing body defining an inlet, an outlet and a valve chamber in flow

communication with the inlet and the outlet; and a plurality of thermostat valves disposed in the valve chamber in a configuration relative to a center of the outlet, each valve controlling flow of coolant from the inlet to the outlet and comprising an area and a valve center; wherein the configuration comprises placement of each valve such that a line extending between a center of the valve to the outlet center does not pass through an area of another valve.

13. The engine of claim 12, wherein the configuration further comprises placement of each valve such that a tangent line extending between a perimeter of the valve area to the outlet center does not pass through an area of another valve in a manner that, in combination with a perimeter of the other valve area, defines an area of the other valve area that is equal to or greater than one-half the other valve area.

14. The engine of claim 12, wherein the housing body forms a flow path from the inlet through the valve chamber.

15. The engine of claim 12, the plurality of valves form more than two rows.

16. The engine of claim 12, wherein the thermostat housing comprises a bypass valve.

17. The engine of claim 12, wherein the thermostat housing comprises at least seven valves.

18. A method of cooling an engine, comprising: passing coolant through each valve of a plurality of valves of a thermostat housing, comprising: a housing body defining an inlet, an outlet and a valve chamber in flow

communication with the inlet and the outlet; and a plurality of thermostat valves disposed in the valve chamber in a configuration relative to a center of the outlet, each valve controlling flow of coolant from the inlet to the outlet and comprising an area and a valve center; wherein the configuration comprises placement of each valve such that a line extending between the valve center to the outlet center does not pass through an area of another valve.

19. The method of claim 18, wherein the configuration further comprises placement of each valve such that a tangent line extending between a perimeter of the valve area to the outlet center does not pass through an area of another valve in a manner that, in combination with a perimeter of the other valve area, defines an area of the other valve area that is equal to or greater than one-half the other valve area.

20. The method of claim 18, the centers of each of the plurality of valves lie on a circle.