Fuel injector especially for diesel engine with integral solenoid valve to connect high and low pressure fuel connections

摘要

A fuel injector especially for diesel engines and engines using heavy oil fuels has a high pressure feed (11) and a low pressure return feed (19) and a control needle (6) pressed into the valve seal (4) by a combination of spring pressure (7) and fuel pressure, via a bleed duct (29). The injector is operated by a solenoid valve (20) which reduces the hydraulic pressure behind the injector needle in short or long fed pulses. The injector is also used in the cold starting phase where fuel is pumped through the injector, between high and low pressures, in order to preheat the fuel and injector prior to starting the engine.