The purpose of this system is to provide a sensitive, dynamic and high-capacity suspension that offers superior ride quality on a variety of surfaces. Pneumatic systems are based jcb generator pdf the fact that gas is compressible, so equipment is less subject to shock damage. The suspension system usually features both self-leveling and driver-variable ride height, to provide extra clearance in rough terrain. The principles illustrated by the successful use of hydropneumatic suspension are now used in a broad range of applications, such as aircraft oleo struts and gas filled automobile shock absorbers, first patented in the U.
Hydropneumatic suspension has a number of natural advantages over steel springs, generally recognized in the auto industry. Suspension and springing technology is not generally well understood by consumers, leading to a public perception that hydropneumatics are merely “good for comfort”. They also have advantages related to handling and control efficiency, solving a number of problems inherent in steel springs that suspension designers have previously struggled to eliminate. Although auto manufacturers understood the inherent advantages over steel springs, there were two problems. Citroën’s application of the system had the disadvantage that only garages equipped with special tools and knowledge were qualified to work on the cars, making them radically different from ordinary cars with common mechanicals. Hydropneumatic suspension offers no natural roll stiffness. This system uses a belt or camshaft driven pump from the engine to pressurise a special hydraulic fluid, which then powers the brakes, suspension and power steering.
Nitrogen is used as the trapped gas to be compressed, since it is unlikely to cause corrosion. A nitrogen reservoir with variable volume yields a spring with non-linear force-deflection characteristics. Citroën first introduced this system in 1954 on the rear suspension of the Traction Avant. The first four-wheel implementation was in the advanced DS in 1955. During World War II, Paul Magès, an employee of Citroën, with no formal training in engineering, secretly develops the concept of an oil and air suspension to combine a new level of softness with vehicle control and self-levelling. 1954 Traction Avant 15H: Rear suspension, using LHS hydraulic fluid.