Hydraulically controlled and cooled unit fuel injector

摘要

A unit injector (200) of the cam actuated, open nozzle type includes an extremely compact injector body (202) having a minimum number of internal flow passages and a two piece injector plunger (222) arranged to provide pressure/time metering, scavenging fuel flow, hydraulic timing and wear compensation in advance timing mode. Sharp cut off of fuel injection without high "crush" loads and wear compensation in retard and advance modes is also provided by the embodiment of Fig. 3. The injector body (202) has an exterior shape designed to form a fuel supply flow path (204) and an isolated fuel drain flow path (206) between the exterior surface of the injector body (202) and the interior surface of the recess (203) in which the injector (200) is received. This arrangement allows a very simple pattern of passages (mostly radial passages) to be formed in the injector body.