TOYOTA TSO40 HYBRID
The front motor has long since been developed – the original plan was to run it during the 2012 season
TOYOTA’S HYBRID HISTORY Back in 2006, Toyota first embarked on the development of a racing hybrid system. Production hybrid cars run most efficiently in the city, where the cars stop and go repeatedly, but the fuel efficiency drops during the high speed running. During a race, cars constantly undergo hard braking, which would create a large amount of energy for hybrid cars. So, gaining expertise in racing would eventually lead to developing a mass production hybrid system which is highly efficient at any speed range. In 2006, Toyota participated in the Tokachi 24 Hours using a new hybrid road car, the Lexus GS450h,
which featured experimental capacitor technology. That was an early test for this potentially useful energy storage system, which can quickly recover and release energy. During the race, in the northern part of Japan, the team collected various data, focusing on understanding how a hybrid system behaves in race conditions. They tried different driving modes and confirmed a 5-10 per cent improvement on fuel efficiency. The development team was back in the Tokachi 24 Hours again in 2007. The previous year’s car had a system that was based on a mass production hybrid
system, but this year’s hybrid system was specially made for the event. The base car was a Supra that was competing in SUPER GT GT500. A Motor Generator Unit (MGU) and a capacitor were installed to assist the Supra’s naturally-aspirated V8 4.5-litre engine. The predominant feature of the car was a fourwheel regenerative system, with additional high power MGU at the rear and in-wheel motors at the front. The extra MGU on the rear was to regenerate the energy efficiently under braking. The Supra HV-R proved a 10 per cent energy efficiency improvement, compared to the car without the hybrid system, during the 3136km 24-hour race in which it achieved overall victory. The victory confirmed that development of the racing hybrid system was moving in the right direction. But at Le Mans, Audi was winning with a diesel engine. To beat the champion at Le Mans, Toyota had to fill the energy efficiency gap between diesel engine and petrol engine first. And then it was necessary to reduce the weight of the hybrid system to improve the performance of the car. According to Toyota’s initial calculations, a hybrid system capable of delivering the performance to win Le Mans would be likely to weigh around 600kg, but to actually have a realistic chance, the system needed to weigh less than 100kg.
THS-R DEVELOPMENT Toyota’s racing hybrid programme stepped up in 2007 with the Supra HVR GT. Yoshiaki Kinoshita started the project, development was handled by Hisatake Murata 22 LE MANS 2014
When Toyota introduced the TS030 HYBRID in WEC, the team had developed a hybrid system called THS-R (Toyota Hybrid System - Racing), which had