Electromagnetic suspension offers better car ride
Drivers are about to get a better car ride quality thanks to a new, active electromagnetic suspension system developed at Eindhoven University of Technology (TU/e) in the Netherlands. Built in cooperation with SKF of Sweden, this innovative suspension system is fitted in cars, making them safer because they no longer roll on turns. Ultimately, the production of more comfortable cars is just round the corner.
The team installed the system in a BMW test car that was exhibited at the AutoRAI show in Amsterdam earlier this month. At a first glance, the BMW 530i hops up and down like a car seen in a hip hop music video clip. 'Of course that isn't the intention,' says Bart Gysen, a TU/e doctoral student and team member. 'But it certainly shows what the system can do.'
According to the researchers, the wheels of the car can rise and fall very quickly, which is one of the special features of the system. While active suspension systems are already in place, they are hydraulic and are not as quick to negate the quick vibrations triggered by the road surface's irregularities. This is where the new system enters the picture; fast changes make for a smoother ride.
The system was evaluated on a testbed in 2010, where road—surface vibrations were stimulated on one single wheel. The team found a 60% jump in the quality of the ride. 'We expect that this increased comfort can also be achieved with a real car,' Mr Gysen says. 'And possibly even more, when all four wheels are fitted with the system.'
Manufacturing more comfortable and safer cars is possible due to improved roadholding. Cars equipped with this suspension system will have a much harder time flipping over, triggered by abrupt steering manoeuvres.
Ambulances would probably be very interested in acquiring this system. 'An ambulance fitted with this system will be able to transport patients quickly and free of disturbing road—surface vibrations,' Mr Gysen explains.
A car's normal shock absorber is replaced with this newer system, which is around the same size as the shock absorber. A strong electromagnetic actuator, a control unit, a passive spring and batteries are part of the package. The researchers say the system's design is based on safety. Both the springing and shock absorbers will still be operational if an electrical power failure ensues. The system's passive spring supplies the spring, and the magnets give passive, magnetic shock absorption.
Commenting on the energy consumed by the system, Mr Gysen says: 'If you install this suspension system on all four wheels, the peak consumption is 500 watt – half of what an air—conditioning system uses. Hydraulic suspension systems use four times as much power. And the consumption of our system can probably be reduced still further by optimisation. This is only the first version.'
It should be noted that the road surface—generated vibrations could produce power, which is then fed back into the battery.