Patent Application
20170175613
The present disclosure relates to thermostats for use with internal combustion engines, and more particularly to a thermostat having a wavy valve plate.
This section provides background information related to the present disclosure which is not necessarily prior art.
Internal combustion engines typically employ a cooling system for maintaining the engine within a desired operating temperature range. The cooling system for many automotive vehicles employs a coolant fluid that is circulated through the cylinder block and cylinder head of the engine and through a radiator. A thermostat is used to regulate the flow of coolant to the radiator so as to maintain the coolant at a desired temperature. Engine outlet side thermostats have historically been problematic with regards to control at low load conditions. In modern systems this can cause the thermostat to continuously open and close at steady state highway speeds. The result is that the radiator can be continuously exposed to thermal cycles to the point where the tubes fatigue and may leak.
The present disclosure provides a thermostat disposed in the coolant passage and including a valve seat and a valve plate engaged with the valve seat in a closed condition and movable away from the valve seat in an open condition, the valve plate having a wavy surface, wherein the wavy seat surface is nonplanar with surface variations of at least 300 microns. The edge of the wavy valve plate contains an elastomeric seal which engages the seat. The wavy valve plate creates a situation where the thermostat operates with two effective control regimes, a fine control for low load conditions where the valve is only traveling between 0 and approximately 1 mm while the wavy plate allows a low coolant flow, and a high flow regime (valve fully open) for high engine load situations that require maximum cooling. In contrast, the flat valve plate designs only have a coarse flow control regime for low load condition and are unable to control radiator flow during low load.
Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.
Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.
Example embodiments will now be described more fully with reference to the accompanying drawings.
Example embodiments are provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail.
The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms “a,” “an,” and “the” may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises,” “comprising,” “including,” and “having,” are inclusive and therefore specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed.
When an element or layer is referred to as being “on,” “engaged to,” “connected to,” or “coupled to” another element or layer, it may be directly on, engaged, connected or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly engaged to,” “directly connected to,” or “directly coupled to” another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.
Spatially relative terms, such as “inner,” “outer,” “beneath,” “below,” “lower,” “above,” “upper,” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. Spatially relative terms may be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the example term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.
With reference to
With reference to
In operation, as the coolant within the engine 12 heats up, the coolant heats the wax pellet 38. As the wax pellet 38 melts, it expands and presses against the rubber body 40 and causes the case 36 to be pushed in a downward direction as depicted in
According to the principles of the present disclosure, the valve plate 34 is formed with a wavy configuration as shown in
As compared to conventional thermostat valve plates that have a planar engagement surface, it has been discovered that the wavy valve plate configuration creates a situation where the thermostat 24 can regulate small amounts of flow during initial opening of the valve plate 34, resulting in an improved flow control as compared to a conventional flat plate design. The fine flow control during initial opening of the valve plate allows the thermostat 24 to be placed further away from the radiator 20 and provides a situation where the thermostat 24 can adjust the flow to a lower steady state value. In particular, the wavy valve plate 34 creates a situation where the thermostat operates with two effective flow regimes, a fine control regime for low load conditions where the valve plate 34 is only traveling between 0 and approximately 1 mm while the wavy plate 34 allows a low coolant flow, and a high flow regime (valve fully open) for high engine load situations that require maximum cooling. In contrast, the flat valve plate designs only has coarse flow control at low flows and is unable to control radiator flow during low load.
Although the wavy valve plate 34 of the present disclosure is described with a thermostat having a particular configuration, it should be understood that the wavy valve plate can be used with other known thermostat configurations. By way of example, the thermostat 24 of the present disclosure includes the valve plate 34 being connected to the case 36 and the piston 42 is fixed to the base 30, while other known thermostats include a valve plate fixed to a movable piston and a case that is fixed to the base in which the wavy valve plate could also be used without departing from the principles of the present disclosure.
The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.
