11-100
140-3 SERIES
STRUCTURE AND FUNCTION, MAINTENANCE STANDARD EXHAUST BRAKE
Operation
Exhaust brake (butterfly valve type)
1. When exhaust brake switch is OFF
When the switch is at the OFF position, solenoid (1)
of the exhaust brake valve is de-energized.
In this condition, ports
A
and
B
of the exhaust brake
valve are closed, and ports
B
and
C
are open.
Therefore, the air entering cylinder (5) of the butter-
fly valve returns from port
B
to port
C
and is
released to the atmosphere, and butterfly valve (7)
fully opens the passage from the turbocharger to the
muffler.
2. When exhaust brake switch is ON
When the switch is turned ON, solenoid (1) of the
exhaust brake valve is energized, plunger (3) and
valve (4) move up, ports
B
and
C
close, and ports
A
and
B
open. The air from the dry tank enters port B
and flows to cylinder (5) of the butterfly valve.
When this happens, the cylinder extends, lever (6)
moves down and butterfly valve (7) fully closes the
passage from the turbocharger to the muffler.
As a result, the engine speed goes down and the
travel speed of the machine when going down hills is
limited.
Even if the switch is ON, if the accelerator pedal is
being depressed, the exhaust brake limit switch is
actuated to stop the engine brake from having any
effect.
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