How Do Electronic Suspension Systems Work?
The basic idea behind simpler electronic suspensions is to use electronically adjustable shocks and/or struts so suspension ride control characteristics can be adjusted or adapted to changing driving conditions, resulting in improved ride and handling.
Electronic shocks and struts have a small electric actuator motor mounted either atop the unit or inside to rotate a control rod or selector valve that opens or closes metering orifices in the piston valve.
This changes the relative stiffness of the shock as it travels through compression and rebound. The next generation of electronic shocks will use solenoids rather than motors because solenoids allow faster response times.
The position of the control rod or selector valve inside the shock or strut is determined by a dash-mounted switch in manually controlled systems and/or a microprocessor in systems with more sophisticated automatic controls.
Electronic shocks are nothing new. The Japanese introduced them to the U.S. market back in 1983 on the Mazda LX626 and the Nissan 300ZX. Since then, they have been offered on a variety of Japanese sports coupes and luxury sedans.
In recent years, systems have been adopted by numerous domestic models as well. The 1988 Lincoln Continental was the first domestically-built vehicle to sport electronically adjustable shocks, followed by the Ford Probe and Corvette in 1989.
One advantage of electronically adjustable shocks/struts that becomes quickly apparent when you are behind the wheel is that no one ride control setting is right for all road conditions. The damper setting that works best depends on the frequency and severity of the oscillations. A soft setting that gives a boulevard-smooth ride under one type of driving condition lacks sufficient dampening action to control the vibrations that are produced under different road conditions.
Conversely, a firm setting may give better ride control under different driving conditions, but become unacceptably harsh under others.
The more complicated systems add automatic load leveling (to compensate for changes in vehicle loading) and/or ride height adjustment (vehicle lowers at speed to reduce wind resistance).
The most advanced electronic suspension today is the optional active suspension under the Infinity Q45. It uses hydraulic actuators instead of conventional or electronic shocks to support a portion of the vehicle’s weight.