Tail rises in response
to upward movement of front wheels eliminating pitch.
Nose rises in response
to upward motion of rear wheels - no pitch.
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HYDROLASTIC SUSPENSION
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THE PRINCIPLE OF THE HYDROLASTIC SUSPENSION The outstanding
feature is its simplicity of operation. The front and rear Hydrolastic
displacers on each side of the car are inter-connected by a small bore
pipe. The system is hermetically sealed and therefore never needs any
further attention during the normal working life of the car. Each displacer
incorporates a rubber spring, and damping of the system is achieved by
rubber valves. So when a road wheel is deflected, fluid is displaced to
the corresponding suspension unit. In turn, it is raised in anticipation
of its wheel encountering the cause of its counterpart's deflection. The
rubber springs are only slightly brought into play and the car is freed
from any tendency to pitch, although full play is given to wheel movement,
producing a soft ride.
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Tail rises in response
to upward movement of front wheels eliminating pitch.
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Nose rises in response
to upward motion of rear wheels - no pitch.
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When front and rear wheels encounter a simultaneous deflection, the fluid suspension stiffens in response to the upward motion and, while acting as a damping medium, transfers the load to the rubber springs giving a controlled, vertical, but level motion to the car.
Suspension stiffens in response to upward motion of front and rear wheels, giving controlled, level, vertical movement. The restriction
of the fluid flow, imposed by the small bore piping, rises with the speed
of the car. The ride is therefore steadied at high speeds and softened
at low speeds a most satisfying condition hitherto only achieved by complex
and costly means.
The drawings
reproduced here are diagrammatic so that the principle of Hydrolastic
suspension is easily seen. In the actual car, the front suspension units
- seen below - are mounted horizontally across the engine bulkhead.
The displacer units can be easily seen in the housing.
General layout of the Hydrolastic suspension with the inter-connecting pipes. Not to be confused
with the Hydro-pneumatic suspension used by Citroen. Their system is not
a hermetically sealed pressure system like the Hydrolastic system used
by BMC.
Citroen use
a hydraulic pump system that raises and lowers the car to different heights.
A more superior system but more costly to manufacture and maintain. The
extraordinary thing about their Hydro-pneumatic system, is that it doesn't
use o-rings as seals. The pistons and bores are machined to incredible
tolerances (microns), making seals unnecessary.
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