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24 Hours of Le Mans 2012 : War of the Hybrids!
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Its diesel-electric vs petrol-electric vs 'conventional' diesel at Le Mans this year. Abhishek Nigam checks out the battle of the hybrids
While alternate fuel vehicles and hybrids are already successfully plying on the roads there is no better place to showcase the effectiveness of this technology other than a racetrack. Audi and Toyota plan on doing just that at the very expensive global shop window of Le Mans, yet it also shows thrift in endurance racing. In 1990, one car's 5,000 kilometers required 2,550 litres of fuel; in 2010, the efficiency winner covered the same distance on 1,875 litres. Three years ago LMP1 cars typically used 19 sets of tyres; in 2010, that was down to 11. The Audi R18 and the Toyota TS030 should reduce those figures even further.
Audi R18 e-tron Quattro
For 2012, Audi have unveiled a new hybrid-powered car that will compete at this year's 24 hours of Le Mans race and as part of its season-long entry in the new World Endurance Championship. . Since a permanent four-wheel drive system is still banned by the FIA for use in sports car and endurance championships, Audi has gone in for a hybrid (yes, you read that right) system which uses a conventional internal combustion motor to power the rear wheels and an electrical system to power the front wheels.
Aptly named the R18 e-tron quattro, this latest race car is an evolution of Audi’s Le Mans-winning LMP1-class R18 TDI which features the latest in ultra light weight materials as well as the ‘e-tron’ moniker which the company started using with electric and hybrid concept cars. It also boasts of being the first LMP1 car to use a diesel hybrid system as well as four-wheel drive. The R18 e-tron quattro sticks with Audi’s trustworthy 3.7-litre V6 turbo diesel engine to power the rear wheels, but also features an electric motor which powers the front wheels. However, as mentioned before, the WEC rules still don’t allow cars to run with a permanent four-wheel drive system. So Audi’s boffins have come up with a slightly different way of doing things.
The electric drive system for the front axle consists of a Motor Generator Unit (MGU) connected to the front wheels through two drive shafts. Under braking, energy is recovered by using the generator part of the MGU to electrically spin a carbon-fibre flywheel running a vacuum sealed accumulator. This energy can be then used to send the recovered power back to the front wheels for a little extra oomph when the driver puts his foot down. But what is more important is not how, but when this system actually works.
The regulations allow 500 kJ of energy to be transferred to the front wheels between two braking phases. So in predetermined braking zones before corners, when the driver drops the anchors, the e-tron system recovers braking energy and stores it in the accumulator. Through the corner itself, only the rear wheels are powered by the diesel engine, ensuring that this R18 doesn’t have a traction advantage over other conventionally powered cars. But as the car comes out of the corner and the driver steps on the gas, the accumulator discharges its stored energy by powering the front wheels, which should give the car a good boost of acceleration in the straights. The energy boost process is defined by the minimum speed of 120km/h stipulated by the regulations, the race strategy selected, the throttle pedal movement and acceleration of the car. This year, for the 24 Hours of Le Mans race in June, Audi Sport Team Joest will be fielding two R18 e-tron quattros as well as a pair of regular diesel powered R18 Ultras, the lightest Le Mans prototypes that Audi Sport has ever built.
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I saw the race Toyota would of won if it wasn't for the accident wait till 2013 I bet Toyota wins it.
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