PREVOST X3-45 2011 Operator'S Manual Download

Page: 114 / 214

Other Features

108

NOTE

When driving with cruise control, the exhaust
brake automatically engages if the selected
cruise speed is exceeded by approximately 4
mph (7 km/h). The exhaust brake is then
disengaged when the speed has returned
close to selected cruise speed, provided that
the engine brake was previously enabled.

NOTE

On vehicles equipped with the I-Shift
transmission, any increase of the braking
power, such as from Auto mode

to Engine

Brake Low

, from Auto mode to Engine

Brake High

or from Engine Brake Low

to Engine Brake High

will deactivate the

cruise control.

EXHAUST BRAKE

The exhaust brake provides about 66 % of the
total available engine braking power. The
exhaust brake is most effective at high engine
speeds (1500 to 2300 rpm). The exhaust brake
is automatically disengaged if the engine speed
drops to or below 1100 rpm.

This engine brake mode provides low braking
power by containing the exhaust gases in the
exhaust manifold, thereby making the engine
work against the back pressure. This provides a
retarding force on the drive wheels.

The following must be in effect for the exhaust
brake function:



The engine brake switch found on the

dashboard is set to the ON position



The

Retarder/Engine Brake Low

button

on the steering wheel controls is depressed



Accelerator pedal is fully released



Engine speed exceeds 1150 rpm

VOLVO ENGINE BRAKE (VEB)

VEB has a higher braking effect than the
exhaust brake. This engine brake mode is most
effective at high engine speeds (1500 to 2300
rpm). It is automatically disengaged if engine
speed drops below 1000 rpm.

The VEB is engaged using the

Retarder/Engine

Brake High

button located on the steering

wheel. It works together with the exhaust brake

to provide to provide 100 % of the maximum
available braking power.

The engine brake control on the steering wheel
is achieved by the use of three buttons: OFF,
LOW

and HIGH

. With the Engine Brake

LOW

button depressed, only the exhaust

brake is engaged. With the Engine Brake HIGH

button, both the exhaust brake and the

compression brake are activated.

VEB = Exhaust Brake + Compression Brake

The following must be in effect for the VEB to
function:



The engine brake switch found on the

dashboard is set to the ON position



The

Retarder/Engine Brake Low

button

on the steering wheel controls is depressed



The vehicle speed is over 7.5 mph (12 km\h)



Engine temperature is greater than 110°F

(43°C)



Accelerator pedal is fully released



Engine speed exceeds 1150 rpm

ENGINE BRAKE – AUTO MODE

(WITH I-SHIFT TRANSMISSION ONLY)

The Auto mode

supplies 66 % of the

maximum available braking power. To engage
the engine brake Auto mode

, set the engine

brake switch to the ON position.

Engine Brake switch

When in Auto mode

, the

engine brake engages
simultaneously with service
brakes upon pressing of the
brake pedal. The engine
braking power varies with the
brake pedal position. The
further the pedal is depressed,
the more total braking power is
provided.