On June 14, there will be 56 cars starting at Le Mans in four classes;
The top category of the four classes at Le Mans is called LMP1—the three letters stand for “Le Mans Prototype.” The
The technical regulations for Le Mans define what is allowed, and what isn’t, for each class. In the GT classes, the rules essentially deal with what can deviate from the street version. For the prototypes, which lack the basis of a street-legal vehicle, things are a bit more complicated. And in 2014, the rules for the top class are nothing short of revolutionary. With a reduced fuel consumption requirement in place, the rule- makers at the Fédération Interna- tionale de l’Automobile (FIA) and the Automobile Club de l’Ouest (ACO) are making the fastest race cars in the world fit for the future. The regulations call for reduced displacement (downsizing), innovative hybridization, and light- weight construction.
To stoke innovation, the engineers were given unpre- cedented freedom in the LMP1-H class. The FIA and ACO declined to mandate a uniform hybrid system. And there are no limits on either displacement or the number of cylinders. Diesel or gasoline, turbo or not—the decision is up to the engineers. Whether there are one or two recuperation systems, battery storage, ultracapacitors or flywheels, nothing’s off-limits. So the engineers at Audi, Toyota, and
In its design of the combustion engine,
05 Fighting weight
In the LMP1-H class, the minimum vehicle weight is set at 870 kilograms. For engineers, minimum means maximum as well—every extra gram means a competitive disadvantage. Yet energy recuperation systems with electric motors and storage media are still quite heavy machinery, notwithstanding the bar-raising advancements achieved in motor racing development. Ultimately, the entire vehicle is state-of-the-art lightweight construction: carbon-fiber monocoque, aluminum engine, carbon-fiber structure for the trans- mission and detail work. And yet the lightweight construction methods cannot compromise robustness, let alone safety, in the least.
The highest recuperation class is the 8-megajoule category. A maximum boost of 8 MJ per 13.6-kilometer lap in Le Mans is permitted for cars with correspondingly powerful energy recovery systems. “Boost” is the term used for applying this stored-up energy. To balance out the boost, the regulations limit fuel consumption for the combustion engines. See the examples in the table to the right for a lap at Le Mans.
The goal of the consumption limits in the LMP1-H class is to get the different drive concepts to compete on one level. After all, it shouldn’t be exciting only in development departments, but also on the racetrack when an 6 MJ gasoline engine faces off against a 2 MJ diesel.
|2 megajoules||5.04 l||4.07 l|
|4 megajoules||4.88 l||3.95 l|
|6 megajoules||4.72 l||3.82 l|
|8 megajoules||4.64 l||3.69 l|
|As of: March 14, 2014|
Two factors are intended to establish equivalence between gasoline and diesel engines. One of them is called the K Technology Factor, the other the Fuel Technology Factor. The Technology Factor has to compensate for the fact that cars with a heavier diesel engine have relatively small recuperation systems and thus are at a disadvantage in the boost department. On the other hand, the fuel factor has to compensate for the fact that gasoline engines are less efficient than diesel engines. These two factors were multiplied by each other, which resulted in the different upper limits for energy and fuel amounts for the gasoline and diesel variants. And to ensure that the two also have to refuel with comparable frequency, the regulations stipulate the appropriate tank sizes for the respective designs. The use of hybrid vehicles at Le Mans is not new, but compared to the technology required today, everything that went before seems passé indeed. Comparison: In 2013, a maximum boost of 500 kilo- joules (0.5 megajoules) was allowed between the braking zones.
The consumption values of LMP1-H vehicles are monitored electronically. Fuel flow meters measure the flow of fuel, while other sensors record the energy called up by pressing the boost button. A black box records all of the data, which the race organizers receive in real time. Violators receive time penalties. The teams don’t have much room for maneuver when it comes to compen- sation: the ACO takes the average value for three laps.
10 Core competence
For its return to the top LMP1 category, in light of all of the specifications,
With the development of both recuperation systems and the storage technology,