Importance

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Abstract

An electromagnetic unit fuel injector for use in a diesel engine includes a housing with a pump therein defined by an externally actuated plunger reciprocable in a bushing and defining therewith a pump chamber open at one end for the discharge of fuel to a spring biased, pressure actuated fuel injection nozzle. The pump chamber is also connected to a spill chamber via a solenoid actuated, normally open, hollow, ported valve controlled passage to permit the ingress and egress of fuel. The spill chamber adjacent to the head end of the valve is in flow communication with a supply chamber at the opposite end of the valve and these chambers are connected to a drain passage and supply passage, respectively and are interconnected to each other by the valve and by a second passage in parallel with the hollow valve. The poppet valve in one embodiment is provided with a pressure assist plunger next adjacent to the head of the valve in the spill chamber so as to be acted upon by spill fuel to effect more rapid opening of the valve. During a pump stroke, the solenoid can be energized to move the valve in position to block flow from the pump chamber to the spill chamber so as to allow the pressurization of fuel by the pump to effect discharge of fuel from the injection nozzle.

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First Claim