Le Mans 2012: The hybrids cometh

It's diesel-electric vs petrol-electric vs 'conventional' diesel at Le Mans this year. Danny Cobbs investigates Audi and Toyota's techno-battle

To explain the finer workings of the R18 e-tron Quattro, the diesel-hybrid Audi is fielding at this year's Le Mans 24 hours, is not a simple task. The basics are easy, but the detail is monumentally and infinitely complex. So I ask Dr Wolfgang Ullrich, head of Audi AG Motorsport, if he had to describe exactly how it works to a complete idiot with the barest of race car knowledge (that's me), how would he succinctly sum it up in one or two sentences.

Audi: not one to do motorsport by halves

The German looks puzzled, ponders for a few moments, and then answers in fluent English: "The power from the turbodiesel is supplemented by the hybrid system, regenerating brake energy into a flywheel that is then fed back into the front wheels under acceleration, while the V6 TDI feeds 510hp to the rear wheels."

Even with my limited race car knowledge I can grasp that, but surely the hybrid system is going to add to the overall weight of the car, Dr Ullrich? "It does, but we've reduced the weight in other areas, such as the gearbox, which we've built out of carbon fibre. Now the R18 e-tron is actually only a fraction heavier than the non-hybrid R18. Obviously our main aim is to win but we also want to prove new technology, too, just as we did with the Quattro rally cars of the 1980s, and Le Mans is the perfect place to showcase it."

The sight we assume most rivals will see

I'm desperate to know how the R18 e-tron handles compared to its non-hybrid sibling, but since I'm unlikely to blag a test drive in either it's fortunate that Allan McNish is also around to give me his firsthand experience. "If I'm being totally honest, when the idea of racing a hybrid car at Le Mans was first put to me I was a bit sceptical", says the two-time Le Mans 24 Hour winner.

"It's not that I didn't think the technology would work, I was just a little concerned over how it would cope with such a long and arduous race. That was my initial thought, but since then I've spent a huge amount of time behind the wheel during testing and it performs incredibly well, much better than I was expecting. It handles much like the non-hybrid R18, too. The noise from the hybrid system was a bit disconcerting to begin with, though. I didn't need to look at my gauges to know it was working because it makes this incredibly din, like a washing machine on full spin cycle, but only louder."

e-tron is at the forefront of new tech...

It's no secret that Audi isn't alone in having a hybrid on the starting grid at this year's Le Mans - Toyota has one too. Emphasising the pioneering approach to this technology which has seen more than 3.5-million Toyota hybrid vehicles sold worldwide, it has just finished extensive testing of the TS030 Hybrid (TS, being the acronym for ToyotaSport).

This car is the successor to the TS010 and TS020 which successfully participated at Le Mans during the 1990s and adopts a similar hybrid system to the Audi - both cars have to strictly adhere to the current race rules. These regulations limit hybrid systems to recovering a maximum of 500kj between braking zones whilst restricting deployment to only two wheels. The main difference between the two, however, is that Audi is utilising an existing car, the diesel R18 which won last year, whereas Toyota has started from scratch, building a brand new car which has a carbon fibre LMP1 chassis and is powered by a V8 3.4-litre normally-aspirated petrol engine.

...'ordinary' R18 Ultra diesel is back-up

Of course both Toyota and Audi want to promote hybrid efficiency and there's no better place to do it than the very expensive global shop window of Le Mans, yet it also shows thrift in endurance racing. In 1990, one car's 5,000 kilometres 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 R18 and TS030 should reduce those figures even further.

Although many eyes will be on both of these cars, the Nissan-backed DeltaWing is probably likely to receive the most attention. It's a fantastic and futuristic-looking thing, which appears to like it has come straight off the pages of a Marvel comic. Surprisingly, for a car that appears to have been designed by Buzz Lightyear, it isn't powered by some experimental nuke-fuelled, quad-turbo V12, instead, it has a humble 300hp, 1.6-litre turbocharged motor which first originated from the Nissan Juke 1.6 DIG-T. That's not to say the DeltaWing body writes out a cheque the engine can't cash. The dramatic styling is more than just a show-stopper; it has been designed to balance weight - it weighs half as much as a conventional LMP car - against aerodynamics. Drag is halved, as is fuel consumption which is also cut by 50 per cent.

New hybrid already collecting silverware

So, with just a few weeks until the start of the world's most enduring motor race, who will be the most likely winner? Allan McNish is in no doubt of the outcome, "Me and Audi, of course", he says without a moment's hesitation. "It will be an interesting 24 hours though, and I'm sure all the other teams will want to prove a point by beating us. I just won't let them". Only time will tell if his predictions come true, and Audi will retain the coveted Le Mans 24 Hours title.

Update:
Between Danny filing his copy and publication of this story, the R18 e-tron Quattro has had its race debut, battling with the 'regular' R18 Ultra for a dominant 1-2-3-4 Audi whitewash at the Spa 6 Hours this weekend. The e-trons led the race initially, before the leading car of Marcel Fassler, Andre Lotterer and Benoit Treluyer (last year's Le Mans winners) had to submit to the challenge of the non-hybrid R18 Ultra driven by Romain Dumas, Loic Duval and Marc Gene.