| 摘要 |
A pump injector comprising a pumping chamber, a valve needle controlling communication between the pumping chamber and one or more outlet openings, and a spill valve controlling communication between the pumping chamber and a low pressure fuel reservoir, in use. The pump injector also comprises an inlet non-return valve arranged to permit fuel to flow from the fuel reservoir to the pumping chamber, in use, but substantially preventing fuel flow in the reverse direction. Alternatively, the pump injector may comprise an abutment piston engageable with the valve needle which defines, in part, a control chamber for fuel, and a control valve controlling communication between the pumping chamber and the control chamber.
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