Injection Pump
Injection pump is a single-plunger mechanical pump. It distributes fuel to fuel injectors in correct firing order sequence, meters fuel according to engine load and speed, pressurizes fuel, and precisely times fuel delivery. See Fig 1 . The injection pump uses a centrifugal governor to limit engine speed to 5400 RPM.
The maintenance-free injection pump is belt driven at one half of crankshaft speed. It is lubricated by the diesel fuel passing through it. Clean fuel is essential for trouble-free pump operation.
The injection pump driveshaft turns the vane pump, cam plate and distributor plunger. Springs hold cam plate and distributor plunger against 4 rollers allowing plunger to turn and move back and forth.
When an intake port on plunger is in line with a filling port in pump body, fuel from vane pump fills the high pressure chamber. The cam plate pushes the plunger squeezing fuel into the high pressure chamber. High pressure chamber pressure can reach approximately 1800 psi (126.6 kg/cm2 ). See Fig 2 .
As plunger continues to turn, outlet ports align with injection ports in pump body. The delivery valve opens under pressure, supplying fuel to fuel injector. Ports in injection pump are arranged so injectors receive fuel in correct firing order.