PREVOST X3-45 VIP 2015, Owner'S Manual

Page: 101 / 190

Other Features 5-23
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.
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
ANTILOCK BRAKING SYSTEM (ABS)
– AUTOMATIC TRACTION CONTROL
(ATC) – ELECTRONIC STABILITY
CONTROL (ESC)
The purpose of the Antilock Braking System
(ABS) is to maintain vehicle stability and control
during braking and to minimize the stopping
distance in any road condition.
On slippery roads and more generally in
emergency situations, over-braking frequently
induces wheel locking. Wheel locking greatly
increases breaking distance on any road
surface. Locked wheels also impede directional
control and cause severe tire abrasion. An anti-
lock braking system provides maximum braking
performance while maintaining adequate control
on slippery roads.
The basis of ABS is constant monitoring of
wheel parameters during braking. Sensors on
each wheel of the front and drive axles
constantly measure wheel speed during braking.
This information is transmitted to a four-channel
electronic processor which senses when any
wheel is about to lock. Modulating valves quickly
adjust brake pressure (up to 5 times every
second) to prevent wheel lock. Each wheel is
therefore controlled according to the available
grip.
In this way, the vehicle is brought to a stop in the
shortest possible time while remaining stable
and under the driver's control.