Releasing details of its racing 911 GT3 R hybrid, Porsche stresses that it is “set apart” from conventional hybrid systems for road cars, both in configuration and components. Porsche will launch a hybrid version of its SUV Cayenne this year with a hybrid Panamera set to follow. Developed and supplied by Williams Hybrid Power, the racecar will be publicly revealed at next month’s Geneva Motor Show.
Instead of batteries, the racing application uses an energy storage system centered on an electromechanical composite flywheel, originally developed for Formula One as a KERS (Kinetic Energy Recovery System). But as well as track use, Williams is also focusing on road vehicles.
Alex Burns, Chairman of Williams Hybrid Power and COO of Williams F1, said that both Williams companies had worked together to bring the technology to the point where it could be tested in a race car and deployed in road vehicles: “We hope that this will be just the start of the evolution of hybrid systems developed in F1 moving across to applications where they can contribute to cleaner and more powerful vehicles.”
In November last year, Williams announced its participation in a mild hybrid road car program, working with Ricardo, CTG, JCB, Jaguar Land Rover, SKF, and Torotrak. The program has been created to demonstrate the potential of flywheel-based hybrid systems with the ability to achieve 30% fuel savings and a similar reduction in CO2 emissions at an on-cost of less than $1600 per unit for use by high-volume, price-sensitive vehicle applications.
The racing Porsche gets drive to all four wheels: electrical drive to the front axle, with two motors each developing 60 W to supplement the car’s 353-kW 4.0-L six-cylinder ICE driving the rear wheels. The electric flywheel power generator is mounted inside the 911 GT3 R’s cabin alongside the driver.
Porsche explains that the flywheel generator is an electric motor that stores energy as rotation – or kinetic – energy. It is charged when the driver brakes, with the two front motors then acting as generators. The flywheel generator is slowed down electromagnetically in the generator mode.
The additional power provided can be used after each charge for six to eight seconds.
The system can be used not only to provide added power but also to cut fuel consumption, allowing the use of a smaller fuel tank to offset some of the weight of the hybrid system and to reduce the number of refueling pit stops required.