Transmission Retarder; Abs Brake (Antilock Braking System) - PREVOST H3-41 Manual

TRANSMISSION RETARDER

A retarder is not a brake but a device that helps to
reduce the speed of a vehicle. It improves vehicle
control, increases driving safety, and permits
more economical operation.
provides slowing power when it is most needed;
such as, when descending mountain roads, in
stop-and-go traffic, and on crowded freeways.
The retarder is provided with a switch on the L.H.
lower control panel and a lever on the directional
column (refer to "Controls & Instruments" section).
It will operate two different ways:
accelerator pedal is released; or, when the
accelerator pedal is released and the break pedal
is depressed - depending if the lever is used.
Extended use will raise the transmission oil
temperature.
The retarder helps to reduce speed on grades
without using the vehicle conventional service
braking system. This virtually eliminates brake
overheating and reduces the risk of a runaway
vehicle. A retarder greatly increases the service
life of brake pads and discs resulting in reduced
brake maintenance costs.
Each time the transmission retarder
NOTE:
system is in operation, the stoplights will
automatically illuminate.
NOTE: For coaches equipped with the Antilock
Braking System (ABS), if the wheels start to lock-
up on slippery roads, the output retarder
automatically will become deactivated until the
wheels roll freely.
ABS BRAKE
(Anti-lock Braking System)
The purpose of the anti-lock braking system is to
maintain vehicle stability and control during
The retarder
braking, and to minimize the stopping distance
regardless of road conditions.
On slippery roads, and more generally in
emergency situations, over-braking frequently
induces wheel locking.
system provides maximum braking performance
while maintaining adequate control on slippery
roads.
when the
Also, on smooth or slippery surfaces, the stopping
distance with locked wheels is greatly extended;
on rough surfaces the problem is tire abrasion.
The basis of ABS is constant monitoring of wheel
parameters during braking.
wheel of axles 1 and 2 continually measure the
wheel speed during braking and this information is
transmitted to a four-channel electronic processor
which senses when any wheel is about to lock.
Modulating valves quickly adjust the brake
pressure (up to 5 times per second) to prevent
wheel locking. Each wheel is therefore controlled
according to the grip available between the tire
and road surface.
In this way, the coach is brought to a stop in the
shortest possible time while remaining stable and
under the driver's control.
CAUTION:
EQUIPPED COACHES MAY NOT BE ABLE TO
BRAKE AS FAST ON SLIPPERY ROADS.
WHENEVER
DRIVERS
PEDAL LIGHTLY SEVERAL TIMES BEFORE
BRAKING.
4-7
OTHER FEATURES
An anti-lock braking
Sensors on each
VEHICLES BEHIND
POSSIBLE, WARN
BY DEPRESSING
ABS-
OTHER
THE BRAKE