BMW in the world

Engines

A wide variety of engines have competed at Le Mans, in attempts to not only achieve greater speed but also to have better fuel economy, and spend less time in the pits. Engine sizes have also varied greatly, with the smallest engines being a mere 569 cc (Simca Cinq) and the largest upwards of 7986 cc (Chrysler Viper GTS-R). Supercharging was an early innovation for increasing output, first being raced in 1929, while turbocharging would not appear until 1974. The first car to enter without an engine run by pistons would be in 1963, when Rover partnered with British Racing Motors to run a gas turbine with mixed success, repeating again in 1965. The American Howmet Corporation would attempt to run a turbine again in 1968 with even less success. Although the engines offered great power, they were notoriously hot and uneconomical for fuel. Another non-piston engine that would appear would be a Wankel engine, otherwise known as the rotary engine. Run entirely by Mazda since its introduction in 1970, the compact engine would also suffer from fuel economy problems like the turbine had, yet would see the success that the turbine lacked. After many years of development, Mazda finally succeeded in being the only winner of the race to not have a piston-powered engine, taking the 1991 event with the 787B. Alternative fuel sources would also play a part in more normal engine designs, with the first non-gasoline car appearing in 1949. The Delettrez Special would be powered by a diesel engine, while a second diesel would appear in the form of the M.A.P. the following year. Although diesel would appear at other t mes over the race existence, it would not be until 2006 when a major manufacturer, Audi, would invest in diesels and finally succeed, with the R10 TDI. Ethanol fuel appeared in 1980 in a modified Porsche 911, taking a class win. Alternative biological fuel sources would return again in 2004 with Team Nasamax's DM139-Judd.[8] In 2008, the use of biofuels (10% ethanol for petrol engines and biodiesel respectively for diesel engines) were allowed. Audi was the first to use next generation 10% BTL biodiesel manufactured from biomass and developed by partner Shell.[9] From 2009 onwards, the Le Mans regulations new from the ACO[10] allow hybrid vehicles to be entered, with either KERS or TERS (Kinetic/Thermal Energy Recovery System) setups, however the only energy storage allowed will be electrical (i.e. batteries), seemingly ruling out any flywheel-based energy recovery systems. Cars equipped with KERS systems were allowed to race in 2009 with specific classification rules. Since 2010, they are able to compete for points and the championship. In 2012 the first victory of an KERS equipped car was recorded. The Audi R18 e-tron was equipped with a flywheel hybrid system from Williams Hybrid Power, which when activated drove the front wheels. Usage of this type of KERS was only allowed in specified zones after the car has accelerated to at least 120kph. Therefore no advantage of the four-wheel-drive could be gained on acceleration out of corners. In the same year, Toyota also started with an hybrid car, the TS030 Hybrid which used the KERS to power the rear wheels. Therefore, its usage was not restricted.