A Regenerative Braking System Using ‘KERS’
a device used to recover, otherwise wasted energy.
I. Abstract -Kinetic Energy Recovery System
or simply ‘KERS’ is a system developed to recover a modest amount of energy during braking of an automobile or a locomotive. This system tries to harvest energy which is otherwise wasted. KERS works on the principle of Regenerative Braking, which uses the braking energy to rotate a flywheel connected to the differential( in an automobile) through a gear mechanism, which when actuated( while braking )uses the energy to spin the flywheel at more than 60,000 rpm. There are various methods of achieving this, most commonly used systems are Electrical KERS and Mechanical KERS. Electrical KERS uses a generator and a battery setup to store the energy while braking, where as a Mechanical KERS system uses a flywheel to accomplish the same, which are discussed in full length of this paper effectively, either way this stored energy is then utilized by the driver to achieve a ‘Boost’ or utilize this energy hence reduce his original energy demand. KERS are effectively applied in Formula 1, 24 Hours of Le Mans and other prestigious races because of the energy boost it offers (around 60 kW in F1). Several companies like Volvo, Mercedes Benz have tried to implement KERS technology to achieve more efficiency and decrease fuel consumption, many hybrid cars use this technology. They have been successfully applied in Tram cars and rail locos in Europe. Other applications even include a bicycle called
the ‘Copenhagen Wheel’ to reduce rider fatigue. In the race to increase efficiency and reduce emissions, salvaging every bit of wasted energy is major step forward for a better tomorrow. II. Introduction - Kinetic energy recovery systems (KERS) is a system that attempts to recover wasted energy while braking. Braking is employed to retard a vehicle or a machine by absorbing kinetic energy and reducing motion, this kinetic energy gets converted into other forms of energy mainly heat, which is dissipated. KERS tries to reduce this generation of heat yet maintain the same retardation rate, whilst converting the kinetic energy into a more useful energy. As we all know work is a higher level energy than heat so thereby making it easier to recover and utilize. This method was first postulated by physicist Richard Feynman in 1950s but it took many years of development and testing to achieve a practical application efficiently. Early systems incorporated heavy flywheels and other equipment which made it very inefficient and defeated the purpose, although newer and more advanced versions reacted to this drawback by using composite materials and other technologies. III. Why do we need KERS? - No actual heat engine can be 100% efficient, when we are using a naturally perishable matter to power our
engines every small drop of fuel counts, more so with ever escalating fuel prices it becomes economically feasible to improve the efficiency of our vehicles and machines. We can make an internal combustion engine efficient only to an extent as it has various methods to lose heat such as from the exhaust gases , through the cylinder walls and other areas which cannot be helped. One way to recover some wasted energy is KERS which works on the principle of Regenerative Braking. Depending on the application , every watt of power saved through this method counts as a watt used by the vehicle, which results in saving the fuel that is to be burned to generate that watt. Hence the system is a little more efficient Fig. 1
IV. Types of KERS - Theoretically any procedure that is employed to recover wasted kinetic energy while braking can be called a type of KERS, but two common methods are very familiar in their applications, these are the two technologies applied in the most common KERS application. 1. Mechanical KERS 2. Electrical KERS 3. Pneumatic KERS A. Mechanical KERS It employs a flywheel type of storage for energy....
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