KAMAZ 5490, Operation Manual

Page: 87 / 327

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Auxiliary brake system
Use the auxiliary brake system in all cases to reduce
the traveling speed and compulsorily when driving on pro-
tracted downgrades in order to prevent over-heating of
braking mechanisms.
On continuous grades up and down the optimum
utilization of the engine braking capacity is possible by
means of:
- auxiliary brake engagement;
- timely downshifting.
Auxiliary brake system works only with the gas pe-
dal not engaged.
Auxiliary brake system of vehicle includes:
- decompression brake . An auxiliary valve in the
head of cylinder block, connecting combustion chamber
and outlet passage, opens in engine operating stroke,
causing compression release. The result is that engine
«braking» is executed;
- engine brake . When the engine brake is engaged
the reverse pressure is created in exhaust system by means of
throttle valve.
The work of engine brake depends upon the engine
crankshaft speed. With increase of revolutions the braking
power and efficiency increase.
Maximum engine crankshaft speed for engine
brake operation:
- for a short period of time 2500 min
-1
;
- for a long period of time 2300 min
-1
.
Optimum engine brake range of operation is from
1500 to 2300 min
-1
.
At low rotation frequency it is necessary in ad-
vance to shift down or to apply the service brake.
- retarder (intarder). The intarder allows to exe-
cute a long time and gradual braking. Intarder operation
manual see in Appendix «Operation manual for ZF-
INTARDER. Inbuilt retarder (intarder) for trucks and
buses with gearbox ZF».
Auxiliary brake system control is carried out by
the brake pedal or the under steering switch, located to the
right of the steering wheel.
Attention!
When ABS system comes into action the auxiliary
brake system is disengaged.
With the auxiliary brake system engaged, do not
release the clutch and do not change the gears
.
Do not engage the auxiliary brake on a slippery
road to avoid the lock of wheels, it spells the vehicle
sidewise skidding.