The 6.2L diesel engine uses the Stanadyne DB2, distributor-type, fuel injection pump (Figure 4-31).
The function of the fuel injection pump is to meter the fuel according to engine power requirements and to inject it at high pressure through nozzles into the combustion chambers of the engine at the correct timing intervals. The metering calls for careful design and construction, as it has to be carried out at a high speed and with great precision, in order to ensure even fuel distribution with smooth running, and sensitive response to power control.
The timing of the injections must also be done with perfect precision, or high efficiency is impossible to achieve,
and since the operating pressure may be as high as 6,000 PSI, the pump itself must be constructed with the utmost care, employing high-grade materials and the finest of working tolerances for the pump elements.
The employment of a separate pumping element for each cylinder, together with suitable means of output control, has been the general practice of fuel injection pump manufacture for some time. The idea of using one pump barrel and a set of plungers to supply all cylinders in turn is a natural one, as it offers obvious savings; the pumping element operates more often (according to the number of cylinders), and is provided with a distributor or means of connecting the pump delivery to each of the injectors in turn.
The distributor type pump is thus an attractive proposition, since the number of pumping elements is reduced to one in all cases.