Retarder - Volvo 9700 US/CAN Driver's Handbook Manual

90 Starting and Driving

Retarder

The function of the retarder is to supplement
the main brake, and it acts as an additional
brake. This function may be based on
an engine brake, or a transmission brake
together with the VEB (Volvo Engine Brake),
which is an exhaust brake combined with a
compression brake.
When the retarder stalk is in its (A) position,
depressing the brake pedal will engage both
the footbrake and the auxiliary brake. This
mode is called "brake blending", and means
that the brake system decides how great a
contribution to the total braking force will
come from the auxiliary brake, and how much
from the footbrake. It allows for optimal use
of the auxiliary brake.
In other situations (1-3) the bus is braked by
the additional brake as soon as the accelerator
pedal is released. The braking force is
increased by moving the lever down and
decreased by moving the lever up.
Note: The retard function works together
with the EBS system. See the separate driver
instructions for "EBS".
DANGER
Avoid using the retarder on slippery roads
because of the risk of locking the wheels
and skidding (the retarder brakes only the
driving wheels). Failure to do so may lead
to an accident, resulting in serious personal
injury or death.
The (B) position of the stalk is only present
in buses fitted with I-shift. For additional
information, see the separate Operating
Instruction "I-shift".
T0010263