As the motorsport world, especially Formula One, struggles to rid itself of its profligate image and show the world that it has something useful to offer, it has turned to energy recovery devices as a shining beacon. The fact that such devices are already well established in the automotive world does not matter, with the introduction of KERS-kinetic energy recovery systems-into Formula One next year, the premier category of the sport is making a statement that it acknowledges the concerns about the environment. Teams can employ any such device they like-electrical or mechanical-which means that all 11 teams in the Formula One paddock are busily assessing which systems are better, with most of them keeping their cards very close to their chest as to which way they will go. However, there has been a great deal of activity and noise at the supplier level with a number of companies flagging up their expertise in energy recovery systems in the hope of landing a big prize-a contract with a Formula One team which could put them on the map in terms of profit and prestige.
In an effort to boost this initiative as well as highlight the significance for road car applications, a group of leading companies in the UK that includes Ford, Jaguar, and Land Rover, have joined together to develop the technology. Established by the British government, the Technology Strategy Board is a business-led executive non-departmental public body with the mission of promoting and supporting research into, and the development and exploitation of, technology and innovation for the benefit of UK business. It caused quite a stir when it recently announced that it was funding nearly $50-million into 16 innovative low-carbon vehicle development projects, one such being a two-year program to develop new flywheel hybrid technology for use in a premium segment passenger car as an alternative solution to other hybrid systems and to prove its effectiveness and viability for production.
There is a strong link with motorsport due to the companies involved. The project is being led by Prodrive, an automotive technology company that has its fingers in very many pies. On the motorsport side, it is responsible for running the factory Aston Martins at Le Mans, while also supporting all the customer teams. For years, it has run the factory Subarus in the World Rally Championship. In the UK, there is an official Alfa Romeo Brera coupe that bears the Prodrive name. However, it does not stop there because David Richards, the company founder and CEO, is also part of the consortium that bought Aston Martin from Ford a few months ago.
Two other companies deeply involved in the project also have their roots firmly embedded in motorsport. Flybrid only came into existence a couple of years ago, but managing partner Jon Hilton is a very well-known and respected name in Formula One circles, having been part of the successful Renault F1 engine team that helped Fernando Alonso on his way to two World Championships. Xtrac, with a large customer base in both Formula One and NASCAR plus many other areas, only makes motorsport transmissions. It has been involved in energy efficient motorsport initiatives since 2001. It recently played a key role in designing, developing and integrating a mechanical KERS system for Formula One with partners Flybrid and Torotrak. Its role in this project is to provide the toroidal continuously variable transmission (CVT) between the flywheel and the vehicle powertrain.
The other companies involved in the project are Torotrak, a developer of toroidal CV-type transmission systems, and Ricardo.
The project will primarily focus on the flywheel hybrid system based on technology recently developed in accordance with new Formula One regulations in which the entire mechanical system recovers the kinetic energy of a vehicle during braking in a high-speed rotating flywheel rather than using an electric motor to store it in batteries, as in current electric hybrids. However, to keep options open, Ricardo’s task is to examine alternative flywheel concepts in parallel with this project.
Such kinetic energy hybrid systems have several potential advantages over full electric hybrids, depending on the application, claims the consortium developing it. They are more efficient in recovering energy during braking and should be substantially cheaper to produce than electric hybrid systems. The flywheel is also better at "deep cycle" charge and recharge, whereby all the energy is either released or recovered from the unit, with no loss in performance over the life of the vehicle, as can be the case with electric-based systems where batteries can lose their ability to fully charge and discharge. The compact layout of the system also makes vehicle packaging and integration simpler. The aim for this flywheel hybrid system is that it does not require any change to the base vehicle platform.
The targets for the new system are to have a round trip efficiency of 70%, with a fuel economy improvement over the NEDC (New European Drive Cycle) of 20%. One of the key advantages is that improvements in real-world fuel economy are expected to be at least as good as that recorded over the NEDC cycle which is not always the case for conventional electric hybrids.
"By providing an additional boost of power, the F1 technology is particularly relevant to the trend to fit cars with smaller engines in pursuit of better fuel efficiency and lower CO2 output," says Xtrac technical director Adrian Moore. "The technical challenge with engine downsizing is compensating for the loss of engine torque and drivability which can be restored by applying flywheel technology. It is also possible that a mechanical KERS system could be used as a range extender in a battery electric hybrid vehicle or even to power vehicle auxiliaries. All are potential applications of the technology, subject to the size of the flywheel, compactness of the system and vehicle packaging requirements. These are all resolvable technical issues. The intent of the KERS technology in Formula One is to consider energy recovery, storage and discharge, and to demonstrate that technology in a novel and effective way."
"We are very excited about being part of a consortium that has successfully secured funding to undertake one of the major UK low carbon vehicle programs," says Peter Digby, Xtrac’s managing director. "Taking a technology that has been developed for motorsport and implementing it for road vehicles in order to improve fuel economy and reduce carbon emissions so quickly after the emergence of the base technology shows how rapidly the UK motorsport industry can react. It is no surprise that a number of our consortium members are successful motorsport engineering companies that have taken up the challenge."
Given the need to develop systems in time for the 2009 season, the CVT has already undergone rigorous bench testing on Torotrak and Flybrid test rigs. The three F1 project collaborators all strongly believe that the mechanics of this system can be transferred to other technology areas including road vehicles. "There are some peculiarities which are distinct to F1 due to the regulations, such as the control system, integration of the ECU and the operating parameters," says Moore, "but as the original Torotrak CVT concept was intended for road vehicle transmissions, the flywheel KERS opportunity readily allows for the use of toroidal CVTs in cars. Historically, there are many instances where a new technology initially looks challenging to install in certain applications only to find a few years later that it is smaller, lighter and performs better than anyone ever envisaged. F1 will certainly help advance this process."
The energy recovery rate and storage requirements of a flywheel for a road car could be considerably less than that required in F1 where the energy which can be recovered from 5-g braking is significant. As the flywheel is required to be charged, some preliminary motion may be required, although road cars could store energy in the flywheel directly from the engine, which is not currently permissible under F1 regulations. Road driving conditions also vary from the stop-start conditions experienced in a town environment to constant speed cruising found on motorways.
"Although still maturing, KERS has stimulated the introduction of radical new technologies to F1 and ultimately to other engineering sectors," says Moore. "The mechanical based concept offers one such solution and indeed could offer significant energy efficient benefits to the driveline of both race and road vehicles."