Vehicular hydraulic system with pressure dump and relief valve arrangement

摘要

A vehicular hydraulic system having a pump, first application, pressure-dump valve and second application arranged in series. The pressure-dump valve diverts a portion of the primary fluid flow past the second application when the pressure exceeds a threshold value. A valve member in the pressure-dump valve defines a pressure-reducing orifice that communicates fluid across the valve member. A check valve prevents flow through the pressure-reducing orifice when the pressure in the valve is below the threshold value. When the pressure exceeds the threshold value, fluid flows through check valve and the pressure reducing orifice resulting in the movement of the valve member and exposure of a bypass port thereby diverting a portion of the primary fluid flow past the second application. The check valve may be selectively variable to provide for the adjustment of the threshold value. A priority valve may also be provided upstream of the first application.