VARIABLE VOLUMETRIC FUEL DELIVERY VALVE ASSEMBLY

PURPOSE: To optimize fuel processing characteristics and actuation of an engine by providing a variable displacement type retraction valve collar on a delivery valve, and providing this with a leak passage provided by a small flat part extended to cross only part of it. CONSTITUTION: In high speed operation of an engine 14, a valve assembly is rapidly moved from a valve seat 100 of it, fuel pressure waves move through a delivery passage 110 of a rotor 62 to a fuel supply passage, and after delivery, rapid retraction is started. During this while, for speed of a valve element 78, flat parts 116, 118 will not have discharge effect because of rapid stop, but only a very little quantity of fuel is brought by the flat parts 116, 118. In low speed operation of the engine 14, the valve element moves toward the valve seat 100 at a relatively low speed, so the flat parts 116, 118 act as fluid leak passages. Capacity of fuel retracted by a retraction collar 96 is thus smaller than that in high speed operation because of leak from around the flat parts 116, 118 into a pocket 106.