Patent ID: 9194352
Filing Date: 2015-11-24
Classification: F02M,F16K,Y10T

Abstract:
1. A pressure relief valve for a common rail fuel system, comprising: a soft metallic valve body having an inner surface defining a high pressure passage separated from a low pressure passage by a conical valve seat; an adapter attached to the soft metallic valve body to define a low pressure chamber fluidly connected to a drain port; a hard ceramic spherical valve member in contact with the conical valve seat, and having an opening hydraulic surface exposed to fluid pressure in the high pressure passage; a soft metallic pin guide with a concave surface in contact with the ceramic spherical valve member in which a yielded contact area between the ceramic spherical valve member and the concave surface matches a spherical shape of the ceramic spherical valve member to distribute a loading force; a spring compressed in the low pressure chamber between the soft metallic pin guide and the adapter; a shim in contact with the spring and having a thickness that sets a preload on the spring to define a valve opening pressure; and wherein the ceramic spherical valve member moves out of contact with the conical valve seat when a pressure in the high pressure passage acting on the opening hydraulic surface exceeds the valve opening pressure.