DETROIT DIESEL 53
12.4
AIR COMPRESSOR
The air compressor
is flange-mounted to the flywheel housing and gear
driven by means of an accessory drive attached to the
camshaft gear.
The air compressor runs continuously while the engine
is running. While the compressor is running, actual
compression of air is controlled by the compressor
governor which acts in conjunction with the unloading
mechanism in the compressor cylinder block. The
governor starts and stops the compression of air by
loading or unloading the compressor when the air
pressure in the system reaches the desired minimum or
maximum pressure.
During the down stroke of each piston, a partial vacuum
is created above the piston which unseats the inlet valve
and then allows air drawn from the air box
Fig. 1.- Typical Air Compressor With Drive
Hub
in the engine cylinder block or through an intake strainer
to enter the cylinder above the piston. As the piston
starts the upward stroke, the air pressure on top of the
inlet valves plus the inlet valve return spring force,
closes the inlet valve. The air above the piston is
further compressed until the pressure lifts the discharge
valve and the compressed air is discharged through the
discharge line into the reservoir.
Fig. 2. - Fixture For Holding Drive While
Installing or Removing Slotted Nut
1972 General Motors Corp.
July, 1972
SEC. 12.4 Page 1
