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KERS at Le Mans

kersHaving looked last month at the McLaren Mercedes KERS system, this month we will investigate the use of energy recovery systems in La Sarthe, the home of the Le Mans 24 Hours.

The ACO (Automobile Club d’Ouest, organisers of the Le Mans 24 Hours) currently incorporate the following section into the technical regulations for LMP1 cars in the ALMS and at Le Mans itself (see end of feature).

KERS is currently only utilised in an ACO sanctioned series by the Corsa Motorsports Ginetta Zytek 09 HS LMP1 car in ALMS, which uses the obligatory electrical KERS system.
The ACO continue to be directed down the KERS route by pressure on two fronts.

Firstly, Peugeot, one of two major car manufacturers who are currently heavily committed to Le Mans, have long since announced their 908 HDi-FAP prototype and are apparently keen to see it enter Le Mans in 2011 at which point hybrid cars will become eligible to score championship points.

Professional motorsport always has been a marketing tool for the major road car manufacturers and Peugeot will doubtless have enviously eyed the PR successes that Audi have had in recent years with their FSI direct injection petrol technology and the TDi diesels.
The French marque is known to be bringing out hybrid production cars in the near future and we can be sure that motorsport will be a key part of that marketing strategy.

Secondly KERS is being used in Formula One and the ACO will not want to be seen as behind the times.

In Formula One McLaren Mercedes have shown that electric KERS can be deployed to good effect although there is not much doubt that the regulations (which limit the amount of energy recovery to a relatively small amount) currently dictate that the effort and cost involved in implementing it are not commensurate with its benefits.

Whilst Formula One as a whole may not be impressed by the system, what the FIA have done is to bring the systems to the attention of the racing public. So will KERS ever be more widely utilised at Le Mans than it has been in Formula One?

The ACO have made it clear teams will not be permitted to use the system to significantly reduce lap times; the implication being that if that happens then either restrictor sizes will be reduced (which would require a re-calibration of the engine) or (more likely) weight penalties would be introduced.

The spirit of the regulations seems clear; teams may use KERS only to reduce fuel consumption, with the added benefit of reducing engine load.

The regulations further limit teams to electrical KERS systems. Energy recovery systems are in general much better suited to slower, heavier vehicles than racing cars; a classic example would be a heavy bus or lorry operating in a mountainous region. Even in that case though the energy storage potential of batteries is very limited; such a case would more probably utilise a pneumatic or hydraulic system.

The ACO is at the very least to be credited for allowing KERS into Le Mans; the race has a proud record of being a proving ground for production car technology and regenerative braking and exhaust system heat recovery will continue that tradition.

Whilst trying to encourage teams to come forward with workable solutions is a positive step outlawing non-electrical energy storage systems such as inertial, pneumatic and hydraulic does seem somewhat of a shame when the technology is in its infancy in motorsport applications.

It also seems somewhat disappointing to have regulations which limit the level of energy storage whilst at the same time promising to peg back anyone who gains a lap time advantage; under current regulations the only reason to develop a system would be if a team could go a lap (or two!) extra between pit stops.

Of course some teams may currently be able to run 13.1 laps between stops and whilst some teams can do 13.9 laps; in which case the second team has a much better incentive for incorporating KERS.

So it would seem that whilst the regulations continue to prohibit the development of an inertial / hydraulic / pneumatic system which could store sufficient energy to repay its development costs in bang per buck terms, the answer is that KERS will probably be an option only for high budget teams.

The Zytek electrical KERS of course remains; but whilst it acts as a fine showcase of the company’s engineering talents their successes will still be determined by the regulations.

1.13 - Energy Recovery System (LMP1 only):
The ACO wants to give to the manufacturers the greatest possible freedom to develop and use such systems while taking a certain number of measures to control them. Energy recovery systems are free, provided they respect the following rules:

- Recovery of energy from the brakes on the four wheels or from the heat of the exhaust fumes.
- Only the rear wheels can be used to propel the car.
- Regarding energy recovery from the brakes, only electric systems are allowed.
- Only the storage of electric energy is permitted.
- The car’s minimum weight is identical to that of the other LM P1s using conventional powertrains (petrol or diesel): 900 kgs.
- The combustion engine and the electric motor must be controlled by the driver using the accelerator pedal (push to pass buttons forbidden).
- The quantity of usable energy stocked on board the vehicle must not exceed 1 MJ.
- Cars must be fitted with homologated sensors which provide all necessary signals to verify the power input and output of motors/generators and the energy released from the motors/generators in one lap

Safety rules that will be imposed by the ACO:
The use of such a system must not be aimed at obtaining additional power but at reducing fuel consumption.
The ACO may adjust the performance of any car using such a system, should it enable the vehicle to improve its lap times in a significant manner.
Competitors who want to develop and use such a system must inform the ACO beforehand and provide all relevant information as to how it works, its use, the performance expected, the safety systems installed etc.
The ACO must be kept informed throughout the development of the system and the car.
It may demand additional information and carry out any checks it deems necessary.

Written by Tom Sharp.

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