Plunger & Barrel Fuel injection Pump (in-line)

Plunger stroke from opening of the inlet port to top dead center

Use is made of symmetrical cams,eccentric cams,and back-kick cam which prevent the engine being started in the false direction of rotation.

Pump and barrel assemblies ( pumping elements) :

plunger and barrel assembly: basic version. The pump plunger together with the pump barrel form the plunger-and-barrel assy. This utilizes the overflow principle in conjunction with port and helix control.

The pump plunger has been so finely lapped into the plunger barrel that it provides and adequate seal even at high pressures and low speeds, and no additional sealing elements are required.

In addition to its vertical slot, the pump plunger has also been machined on the side and the resulting diagonal edge cut in the plunger's wall is termed the control helix.

A single helix suffices for injection pressures up to 600 bar, but above this figure the plunger needs two diametricall opposite helixes, This measure serves to prevent plunger 'seizure' because the plunger is no longer forced against the barrel wall by the injection pressure. The barrel is provided with one or two inlet ports for fuel inlet and end of delivery.

Reversal of plunger travel.

A total stroke.

Plunger-stroke phases:

Due to the precise matching of the plunger to the barrel, it is essential that only complete plunger anc barrel assy are exchanged , and never the plunger or the barrel alone.

Plunger and barrel assy with leakage-return passage ( duct):

If the fuel injection pump is connected to the engine's lube-oil circuit, under certain circumstances leak fuel can result in lube-oil dilution. This is avoided to a great extent by plunger and barrel assy with a leakage-return passage to the pump's fuel gallery. In such cases, the barrel is provided with a right-shaped groove which is connected to the fuel gallery through a separate passage, or the leak oil is collected in a ring-shaped plunger groove and then returned to the fuel gallery through appropriate slots in the plunger.

Versions:

Special requirements calling for the reduction of noise or exhaust emissions , for instance, dictate that some form of load-dependent start-of-delivery ( Port closing ) is provided, plunger versions which in addition to the lower helix also have an upper helix permit the start of delivery to be adjusted as a function of load.

Fuel delivery control using a toothed control rack:

1, pump barrel , 2, inlet port, 3, pump plunger, 4, helix, 5, control rack