Next stop for Toyota a Hybrid victory at Le Mans?

Following Toyota's withdrawal from Formula One, will we see Toyota use their massive TTE facility in Cologue Germany to return to Le Mans and make good on their promise to race more advanced Hybrid technology?

Toyota last raced in the Le Mans 24 hours in 1999 and placed second having never won the race. They have stated a Le Mans win is still on their 'to-do' list and may now hope a hybrid race car will take them to victory. Rival team Peugeot are taking advantage of the new Le Mans hybrid rules and have incorporated the Magnetti Marelli hybrid system into their 908 HY V12 diesel sports prototype.

Toyota had been one of the most public critics of the F1 KERS system and have been quoted as saying they think F1 KERS is 'primative' and not relevant to road car Hybrid systems. Is Toyota abandoning F1 to race under the much more advanced Hybrid rules coming into force at Le mans in 2010 and beyond?

The company says they have already had success with a KERS system more advanced than those allowed under F1 KERS regulations in their Supra HV-R with which they won the Tokashi 24 hour race by 9 laps over second place. The Supra HV-R system is permitted under ATO KERS rules as 4 wheel brake regeneration is mandatory at Le Mans while F1 restrict the KERS system to the rear wheels only.

The technical difference between the two systems is enormous. While F1 KERS is limited to 60kw for 6.6 seconds per lap and can only be used on the rear axle, the Toyota HV-R system has a 150 kw electric motor on the rear axle plus two 10 kw wheel motors on the front wheels. As 70% of all braking effort is on the front wheels the Toyota system can collect a lot more energy per lap.

The FIA Formula One rules may have granted Toyota their wish of four wheel regeneration but they would have had to wait until 2013. The KERS regulations will allow the energy storage limit to be doubled to 800kj (222 wh) by 2011, and KERS will be allowed on both axles with up to 200kW and 1.6MJ (444 wh) of energy storage per lap from 2013. By going to Le Mans Toyota can race a 4 wheel system using wheel motors as early as 2010 and with much less manufacturer competition.

Any LMP1 car contesting the Le Mans 24 Hours with KERS in 2010 has to comply with the following specifications.

− Recovery of energy from the brakes on the 4 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 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.
- The use of such a system must not be aimed at obtaining additional power but at reducing fuel consumption.

The ACO also allow recovery from the exhaust which can be either thermocouple, organic Rankine cycle (ORC) or even perhaps simply an electric generator run off an exhaust gas driven turbo expander very similar to a regular turbocharger.

Toyota admitted they came very close to following Honda out of Formula One at the end of 2008 coincidentally when the ATO first announced KERS rules for Le Mans. We await news of Toyota's 2010 plans with interest.