Will KERS be the Next Big Thing in Consumer Engine Technology?
All photos from volvo.com
Last week, Nicholas D’Amato asserted that as Formula 1 rules and regulations become more restrictive, modern sports cars and supercars have more in common with racing series like World Rally Championship than with the world’s most popular form of motorsport. He noted that those open-wheel race cars lack amenities found on even budget family cars, like ABS, active aero, and traction control. While it doesn’t seem like much technology trickles down from the top these days, there is one notable exception, and it could be a game changer.
That tech comes in the form of a kinetic energy recovery system, or KERS. Under braking, kinetic energy from the wheels is stored in a flywheel as mechanical energy, or converted into electrical energy and stored in a battery (the stored electrical energy is then converted back into mechanical when used). Either the flywheel or battery is connected to the wheels, and in Formula 1, the stored energy can be deployed at the driver’s command for a temporary speed boost. Batteries are used in F1 in lieu of a flywheel for packaging purposes, even though the battery is more inefficient due to its need to convert the different energies. During the race, the unit is charged every time the brakes are applied, but racers can only use the system in certain areas under certain conditions, due to FIA rules. In other forms of racing, like the Le Mans series, the system can be used at any time, provided that the car using the system is traveling faster than 75mph. The next challenge is fitting the system to roadgoing cars, and it’s one being tested right now.
Volvo announced last week that it has tested a preliminary KERS attached to its S60 sedan, and the results are extraordinary. In Volvo’s tests, a turbocharged four-cylinder engine driving the front wheels was mated to a flywheel system that rotated the rears when applied. In Volvo’s tests, the KERS is not user-activated the way it is in F1, but is controlled by the computer and spent when accelerating from a stop or while cruising. Volvo says the system works best while driving in congested areas, when frequent braking allows the flywheel, which spins up to 60,000RPM, to store the most energy. Braking and using that energy means that city drivers use the gasoline engine much less, as it shuts off when KERS is used.
Volvo’s system can also be tapped under heavy acceleration. The unit, which weighs only 13lbs due to its carbon fiber construction, sends an extra 80hp to the rear wheels; under these conditions, then, the car acts like an AWD system with a bias toward the front wheels. The prototype KERS-equipped four-cylinder was able to run from 0-60mph in 5.5 seconds, a jump of 0.4 seconds in the turbo-six S60, and dead even with with S60 R-Design. All of the KERS tech means that a turbocharged four-cylinder has as much horsepower as a turbo-six, but has 25% better fuel economy, according to Volvo, and that’s a monumental achievement. The dual purpose of Volvo’s KERS combines the function of traditional hybrids (which use electric motors to reduce fuel consumption) and F1 racing goals (to provide additional boost when needed).
Volvo isn’t the only one using KERS to boost power output. The Reanult Twizy Concept brought the automaker’s F1 team together with its in-house performance team, RenaultSport, and they attached a KERS unit to the electric Twizy city car. The motor in the Twizy normally develops 17hp, but the addition of the KERS unit boosts power by 100hp. Because the Twizy is a 0-door, 2-passenger vehicle that has more in common with a golf cart than a Golf, it is extremely lightweight, meaning the 117hp in the concept makes the tiny car go from 0-60mph in less than 6 seconds.
The Ferrari LaFerrari will also use a system it calls HY-KERS, which is similar in functionality to a normal KERS unit. Both under braking and when too much torque is produced for the traction control to handle, energy gets diverted to the floor-mounted battery pack that, in conjunction with the V12, produces an astonishing 950hp. No word on whether it will be utilized for conserving fuel economy, but no information from Ferrari suggests this is even a secondary goal.
It will be interesting to see whether Volvo could produce a cost-effective KERS unit for the S60 sports sedan. Such a car would obviously give Volvo an edge over its competitors, something it desperately needs at this point in the game. The BMW 5 Series, Mercedes E Class, and Cadillac CTS all compete for the same customers, and Volvo is routinely outsold by all. A sub-six second sports sedan that consumes fuel like my Volkswagen GTI? Sounds like a recipe for success to me.