Electromagnetic unit fuel injector

摘要

An electromagnetic unit fuel injector for use in a multi-cylinder diesel engine has an externally actuated pump for intensifying the pressure of fuel delivered to a pressure actuated injection valve controlling flow discharge out through a spray outlet and which is normally biased to a closed position by a spring. Pressurized fuel from the pump is also supplied via a throttling orifice to a modulated pressure servo control chamber having a servo piston means operatively associated with the injection valve. A drain passage extends from the servo control chamber with flow therethrough controlled by a solenoid actuated control valve in the form of a poppet valve which is normally biased to a closed position by a valve return spring of predetermined force whereby the control valve is also operative as a pressure relief valve and preferably, a secondary pressure relief valve means is also incorporated into the unit injector so that all of the unit injectors for the engine will operate at a uniform maximum peak pressure.