Engine thermostat having bypass pressure-dampening fluid passage

Abstract

A thermostat assembly ( 200 ) includes an actuator portion ( 106 ) having a sealed container ( 126 ) with an arm ( 108 ) protruding therefrom. A retainer plate ( 118 ) connects the thermostat assembly ( 200 ) to an engine component ( 104 ). A bypass valve plate ( 228 ) is arranged to sealably engage a bypass valve seat ( 134 ) that is formed in another component ( 102 ). The bypass valve plate ( 228 ) includes a body portion ( 402 ) having a central opening ( 408 ) and an outer periphery, an inner rim ( 406 ) surrounds the central opening ( 408 ), an outer rim ( 404 ) surrounds the outer periphery, and a plurality of openings ( 230 ) are formed in the body portion ( 402 ). The plurality of openings ( 230 ) is adjacent to an interface between the body portion ( 402 ) and the outer rim ( 404 ), such that a bypass pressure-dampening fluid passage is defined through the plurality of openings ( 230 ) in the bypass valve plate ( 228 ).

1 . A thermostat assembly, the thermostat assembly capable of being assembled between a first engine component and a second engine component, comprising:
 an actuator portion that includes:
 a sealed container having an arm protruding therefrom, the sealed container containing a substance that expands under increased temperature conditions, 
 a retainer plate that is capable of connecting the thermostat assembly to the second engine component, and 
 a bypass valve retainer; 
   a thermostat plate connected to the actuator portion, wherein the thermostat plate is arranged to sealably engage a radiator outlet seat that is formed in the second engine component;   a bypass valve plate connected to the bypass valve retainer, wherein the bypass valve plate is arranged to sealably engage a bypass valve seat that is formed in the first engine component, the bypass valve plate comprising:
 a body portion having a central opening and an outer periphery, 
 an inner rim surrounding the central opening, 
 an outer rim surrounding the outer periphery, and 
 a plurality of openings formed in the body portion, the plurality of openings disposed adjacent to an interface between the body portion and the outer rim; 
   wherein a bypass pressure-dampening fluid passage is defined through the plurality of openings in the bypass valve plate.   
   
   
       2 . The thermostat assembly of  claim 1 , further comprising the first engine component and the second engine component. 
   
   
       3 . The thermostat assembly of  claim 2 , wherein the bypass valve seat that is formed in the first engine component is substantially flat and surrounds an outlet opening that is formed in the first engine component, and wherein the bypass pressure-dampening fluid passage includes an area between the bypass valve plate and the bypass valve seat. 
   
   
       4 . The thermostat assembly of  claim 1 , further comprising a spring disposed between the bypass valve retainer and the body portion of the bypass valve plate. 
   
   
       5 . The thermostat assembly of  claim 1 , further comprising a spring disposed between the retainer plate and the thermostat plate. 
   
   
       6 . The thermostat assembly of  claim 1 , wherein the substance in the sealed container is wax. 
   
   
       7 . An internal combustion engine comprising:
 a first component having an outlet opening formed therein;   a second component having a radiator return opening in fluid communication with an actuator cavity and a retention groove, wherein the radiator return opening, the actuator cavity, and the retention groove are formed in the second component, and wherein an inlet opening that is in fluid communication with the actuator cavity is defined between the first engine component and the second engine component;   a thermostat assembly that includes:
 an actuator assembly disposed in the actuator cavity, 
 a retainer plate connected to the actuator assembly, wherein the retainer plate at least partially disposed in the retention groove, 
 a thermostat valve operably connected to the actuator assembly, 
 a bypass valve retainer operably connected to the actuator assembly, and 
 a bypass valve plate operably associated with the bypass valve retainer, 
 wherein the bypass valve has a lateral surface, and wherein the lateral surface has a substantially convex conical shape; 
   wherein the first engine component forms a bypass valve seat the is in fluid communication with the outlet opening, wherein the bypass valve seat is arranged to sealably engage the bypass valve plate, and wherein a pressure-dampening fluid passage is defined from the inlet opening, through a passageway between the lateral surface of the bypass valve plate and the bypass valve seat, and the outlet opening.   
   
   
       8 . The internal combustion engine of  claim 7 , wherein the bypass valve seat has a substantially concave conical shape that is arranged to match the convex conical shape of the lateral surface. 
   
   
       9 . The internal combustion engine of  claim 7 , wherein the bypass valve seat is an edge around the outlet opening that is arranged to contact the lateral surface along a line at times when the bypass valve plate fluidly seals the outlet opening. 
   
   
       10 . A method for dampening fluid pressure pulsations for a thermostat comprising the steps of:
 passing a flow of fluid into the thermostat through an inlet opening;   routing the flow of fluid to an outlet opening when a temperature of the fluid is low by sealably engaging a thermostat plate with a seat;   routing the flow of fluid to a radiator outlet opening when a temperature of the fluid is high by sealably engaging a bypass valve plate with a bypass valve seat;   routing the flow of fluid to both the radiator outlet opening and the outlet opening when the temperature of the fluid is between the low temperature and the high temperature;   at times when the fluid temperature is approaching the hot temperature, and the bypass valve plate is approaching the bypass valve seat, providing a pressure pulsation dampening flow path between the bypass valve plate and the bypass valve seat, and passing at least a portion of the flow of fluid through the pressure pulsation dampening flow path.   
   
   
       11 . The method of  claim 10 , further comprising the step of passing at least a portion of the portion of the flow of fluid through a plurality of openings that are formed in the bypass valve plate, wherein the plurality of openings are part of the pulsation dampening flow path. 
   
   
       12 . The method of  claim 10 , wherein the pressure pulsation dampening flow path is defined between a convex conical surface that is formed on a lateral surface of the bypass valve plate and the bypass valve seat that has a concave conical shape. 
   
   
       13 . The method of  claim 10 , wherein the pressure pulsation dampening flow path is defined between a convex conical surface that is formed on a lateral surface of the bypass valve plate and the bypass valve seat that has a sharp edge transition. 
   
   
       14 . The method of  claim 10 , wherein the high temperature is any temperature above about 190 deg.F. (88 deg.C.). 
   
   
       15 . The method of  claim 10 , wherein the low temperature is any temperature below about 190 deg.F. (88 deg.C.).