The Shock eROT-ic: Audi Details Electric-Generating Rotary Dampers

2017 Audi SQ7 (Euro-spec)

Audi’s 48-volt electrical subsystem promises a new world order for suspension and powertrain design. Onward, then, to the company’s third act: Electric rotary dampers to replace traditional tube dampers.

Two years ago, Audi R&D chief Dr. Ulrich Hackenberg referenced a “generator suspension” that would convert a damper’s kinetic energy into electricity. Now there’s a name for it—eROT—which Audi promises has nothing at all to do with composting, just rotation. Audi fits the electromechanical rotary dampers to the rear axle and connects them to the independent rear suspension with vertical links, very similar to an anti-roll bar’s end link. With each bump in the road, the links move up and down, a gearbox converts this linear action into a circular motion, thus turning the alternator to generate current.


Audi claims these dampers generate an average of 100 to 150 watts on German roads. A 0.5-kWh lithium-ion battery in the cargo hold stores the energy. On Audi’s tests across “freshly paved” highways and bumpy back roads, the dampers generate anywhere from three to 613 watts.

But energy recuperation, no matter how small, may be useful to feed Audi’s other 48-volt tricks, such as the electric supercharger in the SQ7 TDI and the electromechanical anti-roll bars in both the SQ7 and Bentley Bentayga. Audi says eROT can separate the compression and rebound strokes in precise, individual motions, so that the vehicle can go soft over a bump and then immediately stiffen. As an added bonus, the horizontal arrangement frees up some cargo space.

While Audi didn’t specify a production timeline, it did hint that the 48-volt subsystem (connected as it is to a normal 12-volt main system) would debut on a “high-performance mild hybrid” next year. Whether this refers to an RS model, the R8, or something completely different is matter for speculation. Top-end VW Group products are already complex enough, and there’s no word from Audi what this system would add in terms of weight and cost.

from Car and Driver Blog

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