With electric vehicles, efficiency is critical. Whether they’re in the wind tunnel carefully massaging a body panel’s aerodynamics, refining motor designs to minimize internal drag or updating a climate control system to consume less power, engineers fight for every fraction of a percent they can to maximize EV range. But there’s one unlikely vehicle system that can help improve efficiency: the suspension.
German supplier company ZF has developed an air suspension system that’s up to 30% more efficient than competing designs. In comparison, the firm’s Twin Compressor setup consumes less power, is lighter and operates nearly silently.
At a recent event in Pontiac, Michigan, Gunasekar Elumalai, systems and applications engineer at ZF explained that this system combines two compressor stages in one unit. The compact design is also oil-free and provides up to 20 bar of pressure (290 psi). Additionally, there’s mechanical intercooling to keep temperatures in check and an internal air dryer comprised of self-cleaning desiccant.
Giving automakers choice, the Twin Compressor, which is of a positive displacement, reciprocating design, can run on either 12 or 48 volts. ZF’s air suspension design is also completely sealed, so no moisture can intrude, even if a vehicle is driven right through standing water. This, of course, is ideal for off-road vehicles or hardworking pickup trucks.
Elumalai said pneumatic systems make noise when they release pressurized air; electric motors and compressors contribute to this as well. Helping minimize racket when a vehicle’s air suspension system is raising or lowering, he said ZF’s Twin Compressor has an “isolated design” that absorbs noise and vibration. “But recently,” he noted, “we bolt a special connecting rod that is dynamically balanced.” This finely tuned rotating assembly produces “less vibration and noise,” so attenuation efforts are greatly reduced.
Like other air suspension systems, ZF’s design offers self-leveling and can provide a range of ride heights, from a lowered entry/exit mode to an elevated off-road setting to a sport mode and everything an OEM desires in between. Thanks to its reduced component count, ZF’s Twin Compressor air suspension system is also designed to be affordable, inexpensive enough to be fitted to low-end vehicles, not just luxury models, which is often the case today.
This system is quieter and more cost-effective than other air suspension designs, though it’s also significantly more efficient. How much of an impact this has on EV range is debatable, but every little bit helps. Pushing forward, Elumalai said, “we are currently working for the next generation.” They’re aiming to “integrate everything within the compressor,” that is, to have one module control everything.
ZF demonstrated the Twin Compressor air suspension system in a Maserati Grecale SUV, but the technology is currently available in a range of different vehicles, including electrics from a variety of automakers, so you can experience it right now.
