Energy recuperating suspension promises to improve fuel efficiency and ride quality for future models.
Imagine a suspension system that converts every movement it undergoes into electricity. Every bump in the road, curve the driver takes, and pothole the wheel dives into would generate electricity for the vehicle. That is the claim behind Audi's prototype eROT system.
Though the concept of a suspension system capable of generating its electricity isn't new German automotive parts manufacturer ZF jointly developed an energy recuperation suspension that uses the flow of hydraulic fluid in 2013 Audi's eROT is said to abandon the traditional upright telescopic shock absorbers for a horizontally arranged electromechanical rotary dampers attached to its rear axle.
These dampers convert the kinetic energy during the suspension's compression and rebound into electricity by means of a lever arm that is attached to the rear wheels' suspension arms. Movements from the wheel carriers that are picked up by the lever arm is transmitted via a series of gears to an electric motor, which converts the kinetic energy into electricity.
Audi says the power output under customer driving conditions would cut back on CO2 emissions by as much as three grams per kilometre.
According to Audi's estimates, the eROT system is able to achieve an average recuperation output of between 100 to 150W on German roads, with outputs ranging from a mere 3W on freshly paved highways to 613W on rough B-roads. Considering Germany's longstanding reputation for maintaining impressively smooth roads, the system's power output might be exponentially larger when put to use on less-than perfect Australian roads.
Even so, Audi says the power output under customer driving conditions would cut back on CO2 emissions by as much as three grams per kilometre, and has the potential of reducing fuel consumption by up to 0.7L/100km. It isn't much, but with ever tightening emission regulations, every little bit helps.
As for energy storage, the eROT system is paired to a 48volt electrical system where its lithiumion battery, in its current configuration, is able to store 0.5kWh of electricity with a peak output of 13kW.
It is not all about dollars and cents. Despite being developed for energy recuperation, Audi says the eROT system is still able to deliver a smooth ride and sharp handling characteristics with an actively controlled suspension system. Furthermore the horizontally mounted electric motors on the rear axle would allow for better vehicle packaging and thus a bigger luggage compartment.
Audi is certainly entertaining the plausibility of the eROT being introduced on future production models, though its application will require the use of an 48volt electrical system. For now the 48volt electrical system is found on the Audi SQ7 TDI and the Bentley Bentayga SUVs, though Audi says the high output electrical system will be the primary electrical system in a new model and will feature in a high performance mild hybrid drive next year. The 48volt system will be introduced over more models eventually.
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