| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a fluid loss/oil pressure fluctuation reducing structure for a common rail fuel injection system, (1) reducing pulsation during pressure feed and preventing high pressure fuel relief loss during pressure control for a high pressure supply pump 5; and (2) reducing high pressure oil bypassing loss through an outlet passage of a nozzle needle valve back pressure chamber controlling fuel injection, for a CR fuel injector 9. <P>SOLUTION: (1) For the high pressure supply pump 5, a variable stroke structure for self-adjusting pressure feed strokes is used to prevent relief losses of high pressure fuel during pressure control, while a delivery valve is provided in a push rod chamber at a position of minimum clearance volume to improve a pressurization performance and a followability to the pressure fluctuation inside a rail 7, for reducing the pressure fluctuation. (2) For the CR fuel injector 9, a poppet valve is employed as the electromagnetic valve for a rapid injection control, and an opening is provided on a cylindrical shaped sliding surface of the poppet valve. For letting high pressure oil flow into the needle valve back pressure chamber, achieving a structure with an inlet area variable with lift of the valve, so that high pressure bypassing losses are reduced by closing the opening during the lift. <P>COPYRIGHT: (C)2004,JPO |
