How Electronic Suspensions Work and Why They Fail
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Car enthusiasts in the United States got their first taste of electronically controlled shocks and struts in the early 1980s when Japanese automakers used the technology on select vehicles to deliver a sportier ride. Since then, just about every major vehicle manufacturer has dabbled at some point in the business of offering vehicles with a form of electronic suspension. These electronic suspension systems have evolved to the point where computers in today’s vehicles are capable of making dozens of changes to suspension dampening and handling characteristics in a fraction of a second. The latest technology delivers an amazing driving experience, but it comes with a price. Vehicles equipped with electronically controlled suspensions cost thousands more. And there’s the high cost of maintenance to deal with down the road. In many cases, the vehicle’s unsuspecting second or third owners are left to clean up an expensive mess when these systems wear out and need to be replaced. Repairs or the replacement of higher-end electronic suspension systems can reach $8,000 with original equipment parts and labor costs. Despite a wide variety of names and marketing campaigns, all of these systems can be separated into two major categories: adaptive and fully active. Adaptive or semi-active systems are the most basic and economical type of electronic suspension. An electronic connection to the strut or shock tells a solenoid valve inside the unit to open or close, altering the flow of its hydraulic fluid. This operation controls the rebound and compression rate of the shock or strut, delivering a softer or firmer ride on demand. Fully active systems are vastly more complicated and more expensive to replace. These systems use more advanced computers and vehicle sensors, incorporating the use of magnetically charged metal particles inside the struts or shocks. When an electric current controlled by the computer system is sent through the strut at a higher rate, it causes the metal particles to increase the viscosity of the hydraulic fluid inside the strut or shock, thus producing a firmer or stiffer ride. When the electric current subsides, the metal particles dissipate inside the shock or strut, thus making the fluid flow easier and ride softer.