US Patent 6837219 Ported pressure relief valve

A ported pressure relief valve (10) used in an automotive fuel system (F) includes an unrestricted constant bleed orifice (32) for routing pressurized fuel from a fuel pump (P) back to a fuel source (T, M) when an engine (E) is running. A check valve (30) prevents flow from a fuel system back to the fuel source when the engine is off, so to retain sufficient pressure in the delivery system that the engine will readily start when cranked. A pressure relief valve (50) drains fuel from the delivery system back to the source of fuel in response to a pressure build up in the fuel delivery system above a predetermined pressure level so to prevent an overpressure condition which would otherwise damage the fuel delivery system.