The KERS debate is ON. You F1 fanatics will like this one and this season the KERS (Kinetic energy recovery system) will be so determining in races were overtaking is difficult who will have what it takes to get the best KERS package and have the edge, and on what expense.
With the return of KERS to F1 in 2011, designers once again face the headache of how best to package the vital yet cumbersome battery packs. But with the 2013 regulations calling for a more powerful KERS, there’s a chance the batteries may be abandoned for the mechanical flywheel KERS system.
Jon Hilton of flywheel specialists Flybrid Systems explained why: “Battery-based KERS systems are not very efficient. Under current regulations, you can release 400 kilojoules of energy every lap, which gives you 6.6 seconds of full power use. The problem is that there’s something like 800kJ available each lap, but because you only need to return 400kJ to the wheels, your system needs to be only 50 per cent efficient to meet requirements. There is no incentive at all to be efficient.”
That could change if the KERS rules are tweaked to allow for more power from 2013. “My understanding is that they’re putting up the power; 120 kilowatts has been mentioned and they’re rumoured to be increasing energy to two megajoules storage per lap,” Hilton said. “At those levels, efficiency is crucial. In a battery-based system, there are losses in turning the energy from mechanical energy at the wheel into electrical energy at the motor and then chemical energy at the battery. Our solution is mechanical – we don’t change the state of the energy at all. There’s a loss, but we put 20 per cent more of the energy back into the wheels than an electrical system. The difference between our efficiency and the efficiency of a battery electric solution is around 2.2 seconds a lap on full KERS boost.”
But if the flywheel is so good, why didn’t the teams adopt it in 2009? After all, Flybrid were working with the Honda team and Williams’ F1 offshoot Williams Hybrid Power were developing their own system.
“If in mid-2007 you wanted a KERS system on the car in 18 months for the first race of 2009, we’d have been a risky bet,” Hilton admitted. “There were unanswered questions on our side. The battery electric solution, while technically inferior, was more mature.
At the same time most car companies were making battery hybrid cars. But the tide is turning. The flywheel is half the weight, half the size and half the cost of a battery solution. We’re involved with manufacturers working on flywheel hybrid road cars now and you’ll be able to buy the first one in 2013.” But flywheels don’t have all the answers.
The general consensus is that while they’re good at peak power output, They’re not so good at storing energy. For battery systems, it’s the other way round. So which will the teams choose? We’ll find out in 2013.