L322 Range Rover System Description and Operation
SUSPENSION
DESCRIPTION AND OPERATION
60-3
Description
General
The main function of the four corner air suspension system is to maintain the vehicle at the correct ride height,
irrespective of load. Additionally, the system allows the driver to request ride height changes to improve off-road
performance or ease of access or loading. The system automatically adjusts the ride height to improve the vehicle
handling and dynamics when speed increases or decreases.
The system will temporarily inhibit height adjustments when the vehicle is subject to cornering, heavy acceleration or
heavy braking. The inhibit function prevents unsettling of the vehicle by reducing the effective spring rates.
Height changes are also inhibited for safety reasons, when a door is opened and the vehicle is stationary for example.
The air suspension system fitted to Range Rover is controlled by an ECU located behind the passenger side of the
fascia. The ECU monitors the height of each corner of the vehicle via four height sensors, which are mounted in-board
of each road wheel. The ECU also performs an 'on-board diagnostic' function to perform 'health checks' on the
system. If faults are detected, codes are stored in the ECU and can be retrieved using TestBook/T4.
The independent front and rear suspension offers many design and performance advantages over the conventional
beam axle design.
Front Suspension
The independent front suspension offers a reduction of un-sprung mass over the conventional beam axle design. The
suspension geometry features positive ground level off-set for improved control under braking. The suspension arms
have been designed for maximum ground clearance. Suspension geometry can be adjusted via the strut top mount
for camber and on the steering rack track rod ends for toe-in.
Front suspension features a 6mm positive off-set.
The following wheel travels are shown for on road and off-road vehicle operation. The difference between the two
operating conditions is a result of operation of the front cross-link valve. When the cross-link valve is opened the
suspension travel is as given for off-road wheel travel. When the cross-link valve is closed the suspension travel given
for on road applies.
The off road mode wheel travel is:
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175 mm bump
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95 mm rebound
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This gives a total of 270 mm off road suspension travel.
The on road standard wheel travel is:
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115 mm bump
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155 mm rebound
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This gives a total of 270 mm on road suspension travel.
The front suspension comprises:
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Two air spring damping struts
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Subframe
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Anti-roll bar
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Anti-roll bar links
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Suspension arms
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Two hub assemblies.
