Fuel-injection timing point control system for fuel injection pump in diesel engine

摘要

The adjustment of the injection time point depends on the pressure difference between the high-pressure (HP) and low-pressure (LP) chambers (22,24). An oil pressure regulating valve alters a fuel pressure in at least one of the two chambers. The valve has a valve body (40), a valve cylinder (44) and a valve seat (37), having first and second truncated conical sections. A valve needle (43) is moved in the cylinder by a control unit. A unit introduces a fuel pressure applied to the valve needle at one of the end sections, in order to balance the pressure at the opposing end section. The first and second truncated conical surfaces when engaged together, form a circular sealing line, at which the conical surfaces butt. This sealing line has a dia. (d1,d6), which is essentially the same as the dia. (d1) of the valve needle.