| 摘要 |
A fuel injection system having a novel electromagnetic actuated fuel pump in which four pumping elements, equally-spaced around a camshaft are mounted such that a pair of opposed pumping elements alternate to deliver pressure to a high pressure common rail with a second pair of the pumping pair of pumping elements. In one embodiment of the invention, the pumping process is mechanically actuated, and in another is electronically actuated. The high pressure common rail is adapted to reduce surges in the fuel pressure from the pump by using central and side chambers connected with cross-drilled orifices. The common rail has a relief valve for safety protection not to allow the pressure in the rail to exceed the maximum preset pressure. The electromagnetic injector has a pressure balanced control valve to control fuel flow to the nozzle and has a pressure assistance mechanism at the end of injection to obtain a sharp end of injection. Also, at the beginning of the next injection, the needle opening can be slowed down to meet the engine requirements.
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