•  The pump is composed of: a feed pump that siphons fuel from the fuel tank into the supply pump, a suction control valve that controls the intake amount of fuel to the pump chamber, a delivery valve that pressure feeds fuel to the common rail, and a pump body.

•  The pump body is composed of a camshaft, outer cam and plunger.

•  The pump is driven by the engine. A pulley on the front end of the pump is connected to the crankshaft via a belt, thus engine torque is transmitted to the outer cam.

•  Two plungers are attached in opposing pairs on the outside of the outer cam. One is used for the intake stroke and the other is for the pressure feed stroke.

•  The regulator valve regulates the fuel pressure within the pump and returns fuel to the fuel tank.

•  Fuel is supplied by the feed pump and sent to the high-pressure chamber formed at the top-dead center point of the plunger through the suction control valve, which controls the intake amount, and passes through the intake valve.

•  As the plunger moves towards the top-dead center point of the high-pressure chamber (direction of increasing fuel pressure), the fuel delivered to the chamber is compressed and sent out the delivery valve, through piping, and pressure fed into the common rail.

•  The reciprocating movement of the cam ring is caused by the eccentric drive of the outer cam due to camshaft rotation. The outer face of the cam ring slides against the plungers, causing them to move reciprocally.