87
Air flows from the engine air filter to the compressor cylinders via reed
-
type
inlet valves. The air compressed by the pistons is forced out to the pneumatic sys-
tem via reed-type delivery valves located in the cylinder head.
The block and head are cooled by the coolant supplied from the engine cool-
ing system. The compressor cooling system is only filled in while the engine is
running.
The oil is supplied to the compressor friction surfaces via a pipe from the en-
gine oil line to the rear cover of the compressor case and through the seal, via the
crankshaft channels to the connecting-rod bearings.
Compressor maintenance.
The valves, which can not keep tightness, should be
set to their seats, worn-out or damaged ones should be replaced.
Set new valves to their seats until continuous ring contact is reached, then
checking it with the help of paint.
Tighten the nuts fastening the block head studs in pairs, starting from the in-
termediate diametrically located pair. Tighten the nuts in two steps: the final tight-
ening torque should be 12-16 N
·
m (1.2-1.6 kgf
·
m).
Signs of compressor failure: noise and rattle, increased heating, excess oil in
condensate, which is usually a result of wear of the piston rings and crankshaft rear
end seal, that of the connecting
-
rod bearings. Compressor drive belt tightening
control and adjustment should be carried out according to YAMZ-236M2, YAMZ-
238M2 Operation Manual
The pressure regulator
is intended to adjust pressure of the compressed air
supplied from the compressor. The compressed air is delivered from the compressor
through outlet IV (Fig. 69) filter 2, duct 12 to circular duct 9. The compressed air is
delivered to outlet II through return valve 10 and then to the truck air bottles. Sim-
ultaneously, the compressed air flows via duct 8 to hollow A under piston 7, which
is loaded by equalizing spring 5. In so doing outlet valve 4 is opened, and inlet
valve 11 is closed.
Fig. 69. Pressure Regulator:
1 - relief valve; 2 - filter; 3 - air
take
-
off duct plug; 4 - outlet valve; 5
- equalizing spring; 6 - bolt; 7 -
equalizing piston; 8, 12 - ducts; 9 -
circular duct; 10 - return valve; 11 -
inlet valve; 13 - relief piston; 14 -
relief valve seat; A-hollow under
equalizing piston; B - hollow above
relief piston; I, III - outlets to atmos-
phere; II - outlet to pneumatic system;
IV - inlet from compressor
