Range Rover Classic
AIR SUSPENSION
1
DESCRIPTION AND OPERATION
ELECTRONIC AIR SUSPENSION - (EAS)
Description
The electronic air suspension is a versatile
microprocessor controlled system that exploits the
advantages of air suspension. It provides a variable
spring rate which achieves near constant ride
frequency for all load conditions, giving:
•
Improved ride quality.
•
Continuity of ride quality, laden or unladen.
•
Constant ride height.
•
Improved headlamp levelling.
The function of the system is to provide five height
modes, each of which is automatically maintained at
the given height by the system logic with the minimum
of driver involvement. Vehicle height is sensed by four
rotary potentiometer type height sensors. Vehicle
height information from each potentiometer signals
the ECU to adjust each air spring by switching the
solenoid valves to hold, add or release air. The
system provides five height settings and automatic
self levelling as follows:
Standard - standard ride height measured from
centre of wheelarch eyebrow to floor = 790mm
±
7mm.
Low profile: 20 mm below standard.
Access: 60 mm below standard.
High profile: 40 mm above standard.
Extended profile: 20 to 30 mm above high profile.
Self levelling
The system provides self levelling under varying
vehicle loads. The vehicle will self level to the lowest
corner height level for 20 seconds after switching off
engine, exiting vehicle and closing doors.
Standard
Vehicle ride height is the same as with conventional
suspension, but is maintained under all load
conditions. This also provides improved headlamp
levelling.
Low profile
This position gives improved handling and fuel
consumption at high speed. When the vehicle speed
exceeds 80 kph (50 mph) for more than 30 seconds,
with INHIBIT switch off, the vehicle will enter the low
profile position. The vehicle will return to standard
height when vehicle speed drops below 56 kph (35
mph) for more than 30 seconds, unless vehicle stops,
in which case it returns to standard when driven away.
The LOWER lamp is illuminated in this condition.
Access
This position makes passenger boarding and luggage
loading easier. With the vehicle stationary, park brake
on (manual), ’P’ selected (automatic), footbrake off,
doors closed and INHIBIT switch off, pressing the
LOWER switch will select the ACCESS position. It is
possible to select access for 15 seconds after
switching engine off. The LOWER lamp flashes until
access position is reached, when it remain constantly
illuminated
NOTE: Opening a door will freeze vehicle
position.
From access the vehicle will return to standard ride
height if:
the RAISE switch is pressed,
or the INHIBIT switched is on,
or park brake is released,
or the is vehicle driven off.
High profile
This position is used to improve approach and
departure angles and when wading. Pressing the
RAISE switch will select this position provided the
road speed is below 56 kph (35 mph) with INHIBIT off.
The vehicle will return to standard position when road
speed exceeds 56 kph (35 mph) or LOWER switch is
pressed. The RAISE lamp is illuminated in this
condition.
NOTE: When raising ride height, rear of
vehicle will raise by 70% of movement first
followed by 70% of front. Rear will raise
remaining 30% before front. Lowering will be
achieved by lowering front of vehicle first. This
will ensure that, with headlamps illuminated, there
is no inconvenience from headlamp dazzle to
other road users. BUT, lowering to access
position will be achieved by the fastest possible
means, by opening all air valves at the same time.
