Patent ID: 7739942

Claim:
A vehicular hydraulic system comprising: a hydraulic circuit having, arranged in series and in serial order along a primary flow path, a hydraulic pump, a first hydraulic application, and a second hydraulic application; and wherein said hydraulic circuit further includes a pressure-dump valve having a valve body and a valve member; said valve body defining an elongate valve chamber defining an axis wherein said valve member is axially slidable within said chamber between a first axial position and a second axial position and sealingly partitions said chamber into a primary flow channel and a low pressure volume; said valve body further defining an inlet port in fluid communication with said primary flow channel; an outlet port in fluid communication with said primary flow channel, a low pressure port in fluid communication with said low pressure volume and a bypass port, said bypass port being disposed at an axially intermediate position with said low pressure port being disposed on one side of said bypass port and said inlet port and said outlet port being disposed on the opposing axial side of said bypass port, said bypass port being sealed from fluid communication with said valve chamber when said valve member is in said first axial position and said bypass port being in fluid communication with said primary flow channel when said valve member is in said second axial position, said valve member being axially displaced from said first axial position to said second axial position when the fluid pressure in said primary flow channel is elevated to a second threshold value; and wherein said pressure-dump valve is operably disposed in said hydraulic circuit downstream of said first hydraulic application and upstream of said second hydraulic application wherein said primary flow path extends from said first hydraulic application to said inlet port, through said primary flow channel and said outlet port of said valve to said second hydraulic application; said bypass port being in fluid communication with said primary flow path at a point downstream of said second hydraulic application and upstream of said hydraulic pump; and wherein the hydraulic fluid pressure in said primary flow path immediately upstream of said first hydraulic application can be elevated to a first threshold value and wherein said first threshold value is greater than said second threshold value.