DIRAVI

The DIRAVI ( "Direction à rappel assistée asserVI " German " assisted steering with dependent return") is a technology developed by the French automobile manufacturer Citroën hydraulic steering system for motor vehicles.

Design and function

The steering system is coupled to the central hydraulics of the vehicle to operation of the suspension system, hydro- pneumatic. One provided for the emergency mechanical connection in the steering gear is only effective if the hydraulic should not be operational. If the system is in operation, the movement is transmitted purely hydraulically from the steering wheel to the steering tie rods.

Driven by a high pressure pump hydraulic enables effortless operation of the steering. In addition, the return of the DIRAVI the steering automatically to the straight ahead position when the steering wheel is released in the state.

The steering is designed to steering commands are implemented very directly and increases with the driving speed, the necessary steering movements of force on the steering wheel. This adjustment of the steering, the minimum effort when parking and at the same time good straight-line stability at high speed guaranteed, is effected by this very special facility DIRAVI.

A hydraulic valve is adjusted depending on speed by a governor front connected to the transmission, so that the forwarded oil pressure with forward speed increases ( and is in the state as well as in walking speed close to zero ). To the steering column a shaped disc is now connected, corresponds to the shape of a heart. A hydraulic piston pushes with the force given by the governor a pinch radially against the contour disc. When driving straight, is the role of depression in the top center of the " heart." When steering is the "heart" twisted out of this straight-ahead, so that the pinch roller migrate out of the well and must be followed by an increasingly steeper contour, thereby thus retracted against the oil pressure of the role incriminating flask. By the variable contact pressure of the roller of the heart outline is produced with an increasing steering angle and the speed of the restoring force in this way. The steering assistance itself is almost always constant. Thus, the significant adaptation effect is caused by the fact that the restoring force of a steering with the vehicle speed ( higher oil pressure ) and the turning angle ( deflected heart stronger ) does not increase, the fact that the steering assist changes as such is; this is of course in the steering line behind the wheel contour.

Rolling stock

For the following Citroen types DIRAVI was - depending on features - built-in:

• Citroën SM
• Citroën CX
• Citroën XM