Delphi's Active Rear Steering System Provides High-Value Solution For Handling Enhancement On Passenger Vehicles

Rear-wheel steering system delivers improved active safety while providing optimal handling characteristics without traditional chassis tuning tradeoffs

PARIS, May 3 -- Delphi Corporation is providing customers and journalists with an opportunity to experience Active Rear Steering for the first time this week at a test track in Mortefontaine, France.

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  Delphi introduced the concept at the Frankfurt Motor Show last fall.

Active Rear Steering is a low-angle rear wheel steering system, specifically designed to offer European vehicle manufacturers an innovative, affordable solution for dynamic handling enhancement and active safety management on passenger vehicles.

"Vehicle suspensions are traditionally tuned with a bias for either handling or ride comfort," said Robert J. Remenar, president of Delphi Steering. "Now vehicle manufacturers can optimize their vehicle's ride and handling characteristics using Delphi Active Rear Steering."

Active Rear Steering can serve as a primary mechanism for enhancing the vehicle's handling performance by using its highly tunable software. Using dynamic control algorithms, the system provides the ability to specifically "dial in" desired handling characteristics. For instance, if the desired vehicle character is for a smoother ride via a softer suspension, Active Rear Steering can be used to help regain the desired handling using an algorithm that dynamically adjusts the rear wheel angle according to a vehicle behavior model. The result is optimized handling performance and ride comfort.

The real beauty of Delphi Active Rear Steering is in the way it helps balance ride and handling performance with improved vehicle dynamics, or active safety, Remenar said.

This combination delivers value to the end user who wants to be safe but also desires superior ride and handling characteristics for every day driving comfort and enjoyment.

"Active Rear Steering separates the yaw and lateral dynamics of the vehicle," said Dr. Jean Botti, chief technologist, Innovation Center, Delphi Dynamics & Propulsion Center. "This gives chassis design and tuning experts a new degree of freedom to control vehicle motion. When combined with the latest in advanced algorithms, Active Rear Steering allows our customers to achieve superior handling performance while also increasing dynamic safety through active rear steering."

Delphi Active Rear Steering helps minimize over steer and under steer at all speeds, and on virtually all surfaces, even during normal driving, without slowing the vehicle. Emergency lane changes, or elk test maneuvers, become more predictable, more manageable and less stressful when rear steering is added to the equation.

Active Rear Steering can be integrated with controlled braking to provide a more effective vehicle system solution to stability control than brakes alone. Together these systems help deliver instantaneous rear steering control to bring a vehicle back on its intended course and blended braking as needed. This approach minimizes any slowing of the vehicle making the correction less intrusive to the driver. In addition, by allowing steering to maintain directional control and braking to slow the vehicle, this integration can help reduce vehicle-stopping distances on split and mixed coefficient surfaces, such as snow and ice, in a stable, controlled manner.

"Active Rear Steering complements and expands the impact of brake-based stability control systems on vehicle dynamics by improving handling and yaw stability," said Botti. "Bringing steering into the equation allows our customers to deliver the ultimate in active safety combined with a comfortable ride and superior handling."

Traditional four-wheel steering benefits seen on today's full size trucks and SUVs in the U.S. are also maintained on passenger car applications. Active Rear Steering will reduce the vehicle's turn circle for added maneuverability during city driving or parking. The system can also be configured with unique algorithms for improved handling and safety while towing a caravan or utility trailer.

The Delphi Active Rear Steering system represents a high-value enhancement for vehicle manufacturers using proven, reliable technology. The system features a low-cost, lightweight and modular actuator flexible enough to work with different suspension configurations.

"Active Rear Steering for passenger cars is a leading edge system in our growing electric steering portfolio," said Remenar.

"With more than two-and-a-half million Delphi electric power steering systems on the road in Europe and nearly two years of Quadrasteer(TM) Four Wheel Steering production in the U.S., our engineers have the experience and expertise to deliver safe, reliable and high-value systems to our customers," he said.