GILLIG LOW FLOOR, Руководство по обслуживанию

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93
Air System
AIR COMPRESSOR
Your Gillig Low Floor bus comes equipped with a Cummins 18.7 heavy-duty air compressor.
The manufacturer of this compressor has determined that it is not
rebuildable. Therefore, if service is required on this unit, contact your
Gillig Parts representative for a remanufactured compressor to install.
The air compressor is flange mounted to the
engine and is coupling driven. Inlet air, oil lubri-
cation, and coolant is supplied from the engine.
Pneumatic pressure signals from the governor
control compression. An integrated pressure
relief valve protects the compressor and engine
if discharge or governor lines become blocked,
or if the compressor cannot unload. The valve
prevents the compressor from pumping above
250 psi in the event of a blocked discharge line
or other malfunction. The swept volume dis-
placement of this compressor is 18.7 cubic feet
per minute.
See Figure 6- 5 to determine whether the air
compressor is a through-drive or non-through-
drive version. The through-drive version is
required to run hydraulic power-steering pumps.
Description
The Cummins 18.7 air compressor provides and maintains air under pressure to operate devices in the
air brake and auxiliary air systems of the bus. It consists of two major subassemblies: the cylinder head
and the crankcase/cylinder block (see Figure 6- 6).
The cylinder head contains the inlet, discharge, and unloader valving, as well as an integral relief valve.
There are two water ports, marked Port 9, an air discharge port, marked Port 2, and an inlet port, marked
Port 0. The cylinder head is mounted on the crankcase/cylinder block. The crankcase/cylinder block con -
tains the cylinder bore, piston, bearings, crankshaft, governor port, and connecting rod.
Figure 6-5, Cummins 18.7 Air Compressors
NON-THROUGH DRIVE THROUGH DRIVE