2.3. Outline of fuel injection pump Yanmar distribution type fuel injection pump YPD-MP consists of a hydraulic head that is equipped with a single plunger, a single distribution shaft, and delivery valves for each individual cylinders, a pump housing that includes camshafts, and a governor, all of which are integrated into the main unit of the pump. For the feed of the fuel, the plunger moves up / down and the distribution shaft rotates with the revolution of the camshaft to distribute the fuel among the cylinders individually.
Specifically, one revolution of camshaft completes three cycles (for three cylinder engine) of a process, including switching over to the high pressure flow path to each cylinder with the distribution shaft, opening delivery valve, high pressure pipe, fuel injection valve, and engine cylinders in this order. This process is repeated by the revolution of the camshaft.
The Flow of the Fuel > orifice Fuel injection pipe Injection pump Fuel filter Timer piston Plunger Thermo-element Distributor shaft Engine coolant Nozzle Accumulator 12/48 Electric fuel feed pump joint Water separator Fuel return tappet Overflow orifice High pressure gallery Fuel tank Cam Engine crankcase Oil seal Engine oil Torochoid pump Low pressure gallery Pressure control valve 6