Renault

Renault is a French automaker producing cars, vans, and in the past, auto rail vehicles, trucks, tractors, vans and also buses or coaches. The Renault Corporation was founded in 1899 as Société Renault Frères by Louis Renault and his brothers Marcel and Fernand. Louis was a bright, aspiring young engineer who had already designed and built several models before teaming up with his brothers, who had honed their business skills working for their father's textiles firm. While Louis handled design and production, Marcel and Fernand handled company management.

The first Renault car, the Renault Voiturette 1CV was sold to a friend of Louis' father after giving him a test ride on 24 December 1898. The client was so impressed with the way the tiny car ran and how it climbed the streets that he bought it.

Electronic Four-Wheel Steering System From Renault

April 9, 2008 Renault is set to introduce its new Active Drive chassis with four-wheel steering with the European introduction of the new high-performance GT versions of the new Laguna Hatch. 
 

Renault System Developed & Renault Technologies produced the Active Drive chassis with four-wheel steering.

If we look at the new Renault system Developed jointly by Renault and Renault Sport Technologies, the Active Drive chassis with four-wheel steering brings many benefits, starting with improved maneuverability, sharpened dynamic response, and unrivaled steering precision giving the driver superb control over the cornering line, achieving new heights in drive ability and active safety.

In town and on country roads, the car is easy to drive because it highly maneuverable and precise. Laguna GT corners with very little body roll and a precise line is achieved with small steering inputs. The Active Drive chassis with four-wheel steering also excels in active safety, both under difficult braking conditions (with a good control over asymmetrical grip and with the ESP matched to a more sporting driving style), and during avoidance maneuvers at speed test.

The Active Drive system builds on this approach by ensuring a more dynamic and more reactive response to make the most of the inherent qualities of Laguna GT's chassis and consequently deliver even greater driving enjoyment.

In addition, for the complex modeling of the vehicle's handling, real-time response to the driver's instructions (every 10 milliseconds) and its ability to adapt to different conditions, Laguna GT's Active Drive four-wheel steering system means that active safety systems are only required as a very last reponse, which means the drivers benefit from more efficient and even more reassuring reactions when faced with an unexpected hazard.

The Active Drive chassis with four-wheel steering makes Laguna GT easy to be handle in town and agile on winding roads. At speeds of less than 38mph (60 km/h), the rear wheels turn in the opposite direction to the front wheels, up to an angle of 3.5°. This brings two advantages: a smaller turning circle, for easy maneuvering; and reduced steering wheel input required thanks to the more direct, specially calibrated steering.

With four-wheel steering on the Active Drive chassis, Laguna GT has a 10% smaller turning circle than with two-wheel steering which is 10.80 meters, incredibly the same as Renault Clio, instead of 12.05m. Enhanced maneuverability is especially noticeable in tight parking situations and it is suitable for women to drive.

With front and rear wheels turning in opposite directions, the car effectively pivots, which means smaller steering angles are needed for the same turning effect. Whereas it takes a 16° steering wheel angle to produce a 1° turn in the front wheels on New Laguna, it takes just 13.5° with the Active Drive chassis. And this drops to 12° when the rear wheels are turned at the maximum 3.5° angle in the opposite direction to the front wheels. Because the steering is more direct, with less need for large steering wheel angles, the impression of maneuverability and agility is greatly enhanced. For any given bend, the driver will need less input on the steering wheel, making for more effective avoidance.

From 38mph(61km/h), the emphasis is on steering precision. The rear wheels turn simultaneously in the same direction as the front wheels, to enhance stability. The Active Drive system with four-wheel steering counters the centrifugal force that tends to push the rear end outwards round bends, and thus raises the safe cornering speed.

The Active Drive chassis with four-wheel steering enhances dynamic handling, with a reassuring response for outstanding driving pleasure. It also improves safety for heightened reassurance during avoidance maneuvers. In an emergency situation, the rear-wheel angle can rise to 3.5°. The involvement of the ESP system, specially configured for a more sporting driving style, is delayed, so that the maneuver can be performed both safely and more swiftly.

Via the ABS unit, the four-wheel steering control unit also detects asymmetrical braking situations, adapting the rear-wheel turn angle automatically to keep the car stable with no driver action required. This also helps the driver keep control during critical situations, and ensures uninterrupted peace of mind during everyday driving conditions.

The Active Drive chassis implements electronic control of the vehicle dynamics. A sensor on the steering column sends steering wheel angle information via the CAN (controller area network) to the four-wheel steer control unit, located behind the rear axle. The four-wheel steer control unit also inputs vehicle speed from the ABS unit and tracks steering wheel angle information to detect sharp steering wheel movements of a sporting driving style or avoidance situation. All these parameters are analyzed to determine the required rear-wheel turn angle, which is implemented by means of an electric actuator on the rear axle.


The controller and electric actuator are supplied by Aisin, a Japanese equipment supplier reputed for its experience in four-wheel steering systems.