After two years of testing a hybrid Flywheel KERS system for road cars, Volvo has revealed their energy recovery system cuts fuel consumption by as much as 25 per cent.
The Hybrid Flywheel KERS system Volvo has developed weighs only 6kg, has a diameter of just 20cm, is made of carbon fibre, sits in a vacuum and is located on the back axle and works by recovering energy under braking which is then stored for use when the car moves off.
After braking to a halt, the KERS Flywheel kicks in as the driver sets off, giving instant torque and making for a swift take-off before the engine, which has been stopped as the Flywheel kicks in, restarts to continue the journey.
Volvo has discovered that fitting the Flywheel KERS system to an S60 with a four cylinder turbo engine gives similar performance to a six cylinder turbo engine but with economy improved by up to 25 per cent.
The system works best in stop start traffic in town – where Volvo reckon it could run the car for up to 50 per cent of the time – but the combination of the Flywheel KERS – which boosts available power by 80bhp for short periods – and the ICE engine means the S60 Volvo used for testing could get to 62mph in 5.5 seconds.
Flywheel propulsion has been around for a while and many car makers have played with it (Porsche and Williams, for example, have been playing with a magnetic KERS Flywheel on the 911 GT3), but Volvo’s system is different because it’s so light, so compact, sits in a vacuum, powers the back axle whilst an ICE engine powers the front and is relatively economical to build.
Derek Crabb, Volvo’s man in charge of powertrain engineering, said:
The testing of this complete experimental system for kinetic energy recovery was carried out during 2012. The results show that this technology combined with a four-cylinder turbo engine has the potential to reduce fuel consumption by up to 25 per cent compared with a six-cylinder turbo engine at a comparable performance level.
Giving the driver an extra 80 horsepower, it makes a car with a four-cylinder engine accelerate like one with a six-cylinder unit.
Which all sounds very promising.
Chris says
I notice Volvo seem to forget to mention that it’s based on British technology. No mention is made of Torotrak, which has designed an infinitely variable transmission (IVT) or Flybrid Automotive of Silverstone which has developed KERS using flywheel energy capture.
PhilipJH says
I can’t see a flywheel KERS having much impact on economy on a motorway but this does look like a cost effective solution for driving in town. How close is it to the real world?