Electronic unit injector.

摘要

An electronic unit injector (12) employs an expandable chamber (134) which expands as pressure in the injector (12) increases between a pair of threshold pressures. The expansion of the chamber (134) results in a two-phase rate of injection of the injector (12) whereby the initial injection rate is significantly lower than the second injection rate. In one embodiment, the expandable chamber (134) is formed by a pin (128) which is displaceable in a cap (120) mounted to the injector body (25). The pin (128) bottoms against the cap (120) to define the phase transition.