FOR RELEASE: May 9, 2002
Detroit, Mich. - General Motors took vehicle handling and comfort to a new level with the January introduction of Magnetic Ride Control on the 2002 Cadillac Seville STS, the world's first production car with this leading-edge active suspension.
GM's Magnetic Ride Control is a complete, stand-alone vehicle suspension control system that uses innovative magneto-rheological fluid-based actuators, four wheel-to-body displacement sensors, and an onboard computer to provide real-time, continuous control of vehicle suspension damping.
The system responds in one millisecond to provide superior ride, handling and control on even the roughest road surfaces. Magnetic Ride Control uses a simple combination of sensors, as well as steering wheel and braking inputs from the driver, to reduce noise, vibration and harshness for a smoother ride.
The system's onboard computer reacts to wheel inputs from the road-sensing suspension by sending an electronic signal to coils in each damper, changing the damping fluid's flow properties. This fluid contains randomly dispersed iron particles that, in the presence of a magnetic field, align themselves into structures adopting a near-plastic state. This action regulates the damping properties of the monotube struts, changing up to 1,000 times per second.
The system offers an expanded range of soft-to-firm damping capabilities for increased control over vehicle motions for a flat ride and precise handling. The active suspension helps maintain the maximum amount of tire patch in contact with the road, providing improved wheel control for a safer more secure ride. This new technology also helps reduce the traditional tradeoff between ride and handling.
Magnetic Ride Control is superior to the traditional suspensions and the real-time-damping systems found in other performance and luxury vehicles that use an electromechanical valve to control hydraulic pressure for shock damping.
Engineers at GM Research & Development laboratories, and later with experts at Delphi Automotive Systems, explored ways to reduce or even eliminate the inherent restrictions of valve-based damping systems. The result is GM's revolutionary system that eliminates electro-mechanical valves entirely.
Magnetic Selective Ride Control will debut as standard equipment in the 50th anniversary Chevrolet Corvette for the 2003 model year. That system will feature tour and sport suspension settings. The tour mode, with its extended range of damping capability, is so capable that it alone provides all the control an everyday driver needs. The sport mode, provides an extra measure of control and feel for performance enthusiasts who want to take their cars on track.
This technology yields greater levels of tuning precision and ride quality. Ride and handling engineers developing vehicles with Magnetic Ride Control can spend their time adjusting the algorithms that control the damping responses on a computer, and are enabled to fine-tune ride and handling characteristics to unprecedented levels of specificity. As a result, drivers will notice better ride quality, less body roll and improvements in overall handling.
General Motors (NYSE: GM), the world's largest vehicle manufacturer, designs, builds and markets cars and trucks worldwide. In 2001, GM earned $1.5 billion on sales of $177.3 billion, excluding special items. It employs about 362,000 people globally.
Magnetic Ride Control: Fact Sheet
What is Magnetic Ride Control?
Magnetic Ride Control is a complete, stand-alone vehicle suspension control system that uses magneto-rheological fluid-based actuators, four wheel-to-body displacement sensors, and an on-board computer to provide real-time, continuous control of vehicle suspension damping.
How does it work?
Magnetic Ride Control is made possible by the development of magneto-rheological (MR) fluid located inside the monotube shock dampers. The fluid is a suspension of magnetically soft, tiny iron particles in a synthetic hydrocarbon-based solution. The fluid's consistency can be manipulated through the precise application of electronic current, resulting in continuously variable, real-time damping. In fact, the development of MR fluid is so significant that medical researchers have adapted it for use in high-tech prosthetic devices, such artificial knees.
What are its benefits?
The system provides a greatly expanded range of soft to firm damping capability, a truly continuous range of damping settings providing increased control over vehicle motions for a flat ride and more precise handing. The enhanced road-holding capabilities improve wheel control for a safer, more secure ride.
Magnetic Ride Control offers greater roll control and handling during transient maneuvers, and helps reduce noise, vibration and harshness for a smoother ride. This new technology helps reduce the traditional tradeoff between ride and handling, and responds 5 times faster than previous real-time damping systems. In addition, greater reliability is possible with its simpler design.
The 2002 Cadillac Seville STS is the world's first production car with this leading-edge active suspension.
Magnetic Selective Ride Control will debut in 2003 as standard equipment in the 50th anniversary Chevrolet Corvette. The system also will be optional on other 2003 Corvette coupe and convertible models, except the Z06.
Alan D. Gagne, GM Communications