THEORY OF OPERATION -- CONTINUED
AUXILIARY POWER UNIT (APU) -- CONTINUED
The fuel system consists basically of a primary (23) and secondary fuel filter (24), fuel transfer pump (25), injection
pump (26), injection nozzles (27) and fuel sediment bowl (28). The transfer pump (25), operating off the camshaft
draws fuel from the supply tank, through the fuel sediment bowl (28) and delivers it through two filters (23, 24) to
the injection pump (26). The injection pump (26) meters and delivers the fuel at high pressure to the nozzles (27).
GAS/PARTICULATE FILTER UNIT (GPFU), M2A2 AIR PURIFIER WITH M3 HEATERS
The gas/particulate filter unit (GPFU) installation in the M88A2 HRV is made up of two separate M2A2 systems.
One M2A2 GPFU (1) is located on the left side of the vehicle. It serves the driver and positions on the left side of
the vehicle and is operated by control assembly (2) to the right of drivers position. The M2A2 GPFU (1) on the left
side is equipped with two M3 air heaters (3). The other M2A2 GPFU (1) is located on the right side of the vehicle
and serves the commander, mechanic and positions on the right side of the vehicle, and is operated by control as-
sembly (2) located left of the mechanics position. This system is equipped with only one M3 heater (3). The GPFU
supplies filtered air through hoses to NBC mask worn by personnel.
The three M3 heaters (3) in the GPFU systems are individually controlled by switches (4) located on each M3 heat-
er (3). The switch on control assembly (2) must be in the ON position to operate the M3 heaters (3). The M3 heat-
ers (3) heat the filtered air provided by the M2A2 GPFU prior to the air entering the individual NBC mask.