Regenerative brake - AbsoluteAstronomy.com

A regenerative brake is an energy recovery

Energy recovery

Energy recovery includes any technique or method of minimizing the input of energy to an overall system by the exchange of energy from one sub-system of the overall system with another...

mechanism which slows a vehicle or object down by converting its kinetic energy

Kinetic energy

The kinetic energy of an object is the energy which it possesses due to its motion.It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity. Having gained this energy during its acceleration, the body maintains this kinetic energy unless its speed changes...

into another form, which can be either used immediately or stored until needed. This contrasts with conventional braking systems, where the excess kinetic energy is converted to heat by friction in the brake linings and therefore wasted.

The most common form of regenerative brake involves using an electric motor

Electric motor

An electric motor converts electrical energy into mechanical energy.Most electric motors operate through the interaction of magnetic fields and current-carrying conductors to generate force...

as an electric generator. In electric railway

Rail transport

Rail transport is a means of conveyance of passengers and goods by way of wheeled vehicles running on rail tracks. In contrast to road transport, where vehicles merely run on a prepared surface, rail vehicles are also directionally guided by the tracks they run on...

s the generated electricity is fed back into the supply system

Railway electrification system

A railway electrification system supplies electrical energy to railway locomotives and multiple units as well as trams so that they can operate without having an on-board prime mover. There are several different electrification systems in use throughout the world...

, whereas in battery electric

Battery electric vehicle

A battery electric vehicle, or BEV, is a type of electric vehicle that uses chemical energy stored in rechargeable battery packs. BEVs use electric motors and motor controllers instead of, or in addition to, internal combustion engines for propulsion.A battery-only electric vehicle or...

and hybrid electric

Hybrid vehicle

A hybrid vehicle is a vehicle that uses two or more distinct power sources to move the vehicle. The term most commonly refers to hybrid electric vehicles , which combine an internal combustion engine and one or more electric motors.-Power:...

vehicles, the energy is stored in a battery

Battery (electricity)

An electrical battery is one or more electrochemical cells that convert stored chemical energy into electrical energy. Since the invention of the first battery in 1800 by Alessandro Volta and especially since the technically improved Daniell cell in 1836, batteries have become a common power...

or bank of capacitor

Capacitor

A capacitor is a passive two-terminal electrical component used to store energy in an electric field. The forms of practical capacitors vary widely, but all contain at least two electrical conductors separated by a dielectric ; for example, one common construction consists of metal foils separated...

s for later use. Energy may also be stored mechanically via pneumatics

Compressed air energy storage

Compressed Air Energy Storage is a way to store energy generated at one time for use at another time. At utility scale, energy generated during periods of low energy demand can be released to meet higher demand periods....

, hydraulics

Hydraulic hybrid

Hydraulic Hybrid Vehicles or HHVs are vehicles that use pressurized fluid, instead of electric power, as an additional or alternative power source along with an engine.- Principle of Operation :...

or the kinetic energy of a rotating flywheel

Flywheel energy storage

Flywheel energy storage works by accelerating a rotor to a very high speed and maintaining the energy in the system as rotational energy...

The motor as a generator

Vehicles driven by electric motor

Electric motor

An electric motor converts electrical energy into mechanical energy.Most electric motors operate through the interaction of magnetic fields and current-carrying conductors to generate force...

s use the motor as a generator

Electrical generator

In electricity generation, an electric generator is a device that converts mechanical energy to electrical energy. A generator forces electric charge to flow through an external electrical circuit. It is analogous to a water pump, which causes water to flow...

when using regenerative braking: it is operated as a generator during braking and its output is supplied to an electrical load; the transfer of energy to the load provides the braking effect.

Regenerative braking is used on hybrid gas/electric automobiles to recoup some of the energy lost during stopping. This energy is saved in a storage battery and used later to power the motor whenever the car is in electric mode.

Early examples of this system were the front-wheel drive

Front-wheel drive

Front-wheel drive is a form of engine/transmission layout used in motor vehicles, where the engine drives the front wheels only. Most modern front-wheel drive vehicles feature a transverse engine, rather than the conventional longitudinal engine arrangement generally found in rear-wheel drive and...

conversions of horse-drawn cabs

Cabriolet (carriage)

A cabriolet is a light horse-drawn vehicle, with two wheels and a single horse. The carriage has a folding hood that can cover its two occupants, one of whom is the driver. It has a large rigid apron, gracefully upward-curving shafts, and usually a rear platform between the C springs for a groom...

by Louis Antoine Krieger (1868–1951). The Krieger electric landaulet

Landaulet

A landaulet or landaulette is a car body style, "an enclosed sedan or coupé with a folding top at the extreme rear quarter, over the rear seat."...

had a drive motor in each front wheel with a second set of parallel windings (bifilar coil

Bifilar coil

A bifilar coil is an electromagnetic coil that contains two closely spaced, parallel windings. In engineering, the word bifilar describes wire which is made of two filaments or strands. It is commonly used to denote special types of winding wire for transformers. Wire can be purchased in bifilar...

) for regenerative braking. In England, the Raworth system of "regenerative control" was introduced by tramway operators in the early 1900s, since it offered them economic and operational benefits as explained by A. Raworth of Leeds in some detail. These included tramway systems at Devonport (1903), Rawtenstall, Birmingham, Crystal Palace-Croydon (1906) and many others. Slowing down the speed of the cars or keeping it in hand on descending gradients, the motors worked as generators and braked the vehicles. The tram cars also had wheel brakes and track slipper brakes which could stop the tram should the electric braking systems fail. In several cases the tram car motors were shunt wound instead of series wound, and the systems on the Crystal Palace line utilized series-parallel controllers. Following a serious accident at Rawtenstall, an embargo was placed on this form of traction in 1911. Twenty years later, the regenerative braking system was reintroduced.

Regenerative braking has been in extensive use on railways for many decades. The Baku-Tbilisi-Batumi railway (Transcaucasian railway or Georgian railway) started utilizing regenerative braking in the early 1930s. This was especially effective on the steep and dangerous Surami Pass. In Scandinavia the Kiruna to Narvik railway carries iron ore from the mines in Kiruna in the north of Sweden down to the port of Narvik in Norway to this day. The rail cars are full of thousands of tons of iron ore on the way down to Narvik, and these trains generate large amounts of electricity by their regenerative braking. From Riksgränsen on the national border to the Port of Narvik, the trains use only a fifth of the power they regenerate. The regenerated energy is sufficient to power the empty trains back up to the national border. Any excess energy from the railway is pumped into the power grid to supply homes and businesses in the region, and the railway is a net generator of electricity.

An Energy Regeneration Brake

Energy Regeneration Brake

The Energy Regeneration Brake was the name for a system designed to automatically switch an electric motor into a generator as the vehicle slowed...

was developed in 1967 for the AMC

American Motors

American Motors Corporation was an American automobile company formed by the 1954 merger of Nash-Kelvinator Corporation and Hudson Motor Car Company. At the time, it was the largest corporate merger in U.S. history.George W...

Amitron

The Amitron was an American electric concept car built in 1967 by American Motors Corporation and Gulton Industries of Metuchen, New Jersey.- Design :...

. This was a completely battery

Battery electric vehicle

powered urban concept car

Concept car

A concept vehicle or show vehicle is a car made to showcase new styling and or new technology. They are often shown at motor shows to gauge customer reaction to new and radical designs which may or may not have a chance of being produced....

whose batteries were recharged by regenerative braking, thus increasing the range of the automobile.

Many modern hybrid and electric vehicles use this technique to extend the range of the battery pack. Examples include the Toyota Prius

Toyota Prius

The Toyota Prius is a full hybrid electric mid-size hatchback, formerly a compact sedan developed and manufactured by the Toyota Motor Corporation...

, Honda Insight

Honda Insight

The Honda Insight is a hybrid electric vehicle manufactured by Honda and the first production vehicle to feature Honda's Integrated Motor Assist system. The first-generation Insight was produced from 1999 to 2006 as a three-door hatchback...

, the Vectrix

Vectrix

Vectrix is an electric vehicle company based in Middletown, Rhode Island, United States, with research and development facilities in New Bedford, Massachusetts...

electric maxi-scooter, the Tesla Roadster

Tesla Roadster

The Tesla Roadster is a battery electric vehicle sports car produced by the electric car firm Tesla Motors in California. The Roadster was the first highway-capable all-electric vehicle in serial production available in the United States. Since 2008 Tesla has sold 2,024 Roadsters in 30 countries...

, and the Chevrolet Volt

Chevrolet Volt

The Chevrolet Volt is a plug-in hybrid electric vehicle manufactured by General Motors. The Volt has been on sale in the U.S. market since mid-December 2010, and is the most fuel-efficient compact car sold in the United States, as rated by the United States Environmental Protection Agency...

Limitations

Traditional friction

Friction

Friction is the force resisting the relative motion of solid surfaces, fluid layers, and/or material elements sliding against each other. There are several types of friction:...

-based braking is used in conjunction with mechanical regenerative braking for the following reasons:

The regenerative braking effect drops off at lower speeds; therefore the friction brake is still required in order to bring the vehicle to a complete halt. Physical locking of the rotor is also required to prevent vehicles from rolling down hills.
The friction brake is a necessary back-up in the event of failure of the regenerative brake.
Most road vehicles with regenerative braking only have power on some wheels (as in a two-wheel drive
Two-wheel drive
Two wheel drive or 2WD describes vehicles with a drivetrain that allows two wheels to receive power from the engine simultaneously.-Four wheeled vehicles:...

car) and regenerative braking power only applies to such wheels because they are the only wheels linked to the drive motor, so in order to provide controlled braking under difficult conditions (such as in wet roads) friction based braking is necessary on the other wheels.
The amount of electrical energy capable of dissipation is limited by either the capacity of the supply system to absorb this energy or on the state of charge of the battery or capacitors. No regenerative braking effect can occur if another electrical component on the same supply system is not currently drawing power and if the battery or capacitors are already charged. For this reason, it is normal to also incorporate dynamic braking to absorb the excess energy.
Under emergency braking it is desirable that the braking force exerted be the maximum allowed by the friction between the wheels and the surface without slipping, over the entire speed range from the vehicle's maximum speed down to zero. The maximum force available for acceleration is typically much less than this except in the case of extreme high-performance vehicles. Therefore, the power required to be dissipated by the braking system under emergency braking conditions may be many times the maximum power which is delivered under acceleration. Traction motors sized to handle the drive power may not be able to cope with the extra load and the battery may not be able to accept charge at a sufficiently high rate. Friction braking is required to dissipate the surplus energy in order to allow an acceptable emergency braking performance.

For these reasons there is typically the need to control the regenerative braking and match the friction and regenerative braking to produce the desired total braking output. The GM EV-1

General Motors EV1

The General Motors EV1 was an electric car produced and leased by the General Motors Corporation from 1996 to 1999. It was the first mass-produced and purpose-designed electric vehicle of the modern era from a major automaker, and the first GM car designed to be an electric vehicle from the...

was the first commercial car to do this. Engineers Abraham Farag and Loren Majersik were issued two patents for this brake-by-wire
Brake-by-wire
Drive-by-wire technology in automotive industry replaces the traditional mechanical and hydraulic control systems with electronic control systems using electromechanical actuators and human-machine interfaces such as pedal and steering feel emulators...

technology.

Electric railway vehicle operation

During braking, the traction motor

Traction motor

Traction motor refers to an electric motor providing the primary rotational torque of a machine, usually for conversion into linear motion ....

connections are altered to turn them into electrical generators. The motor fields are connected across the main traction generator (MG) and the motor armatures are connected across the load. The MG now excites the motor fields. The rolling locomotive or multiple unit wheels turn the motor armatures, and the motors act as generators, either sending the generated current through onboard resistors (dynamic braking

Dynamic braking

Dynamic braking is the use of the electric traction motors of a railroad vehicle as generators when slowing the Locomotive. It is termed rheostatic if the generated electrical power is dissipated as heat in brake grid resistors, and regenerative if the power is returned to the supply line...

) or back into the supply (regenerative braking).

For a given direction of travel, current flow through the motor armatures during braking will be opposite to that during motoring. Therefore, the motor exerts torque

Torque

Torque, moment or moment of force , is the tendency of a force to rotate an object about an axis, fulcrum, or pivot. Just as a force is a push or a pull, a torque can be thought of as a twist....

in a direction that is opposite from the rolling direction.

Braking effort is proportional to the product of the magnetic strength of the field windings, times that of the armature windings.

Savings of 17% are claimed for Virgin Trains

Virgin Trains

Virgin Trains is a train operating company in the United Kingdom. It operates long-distance passenger services on the West Coast Main Line between London, the West Midlands, North West England, North Wales and Scotland...

Pendolinos

British Rail Class 390

The Class 390 Pendolino is a type of train used in Great Britain. They are electric multiple units using Fiat's tilting train pendolino technology and built by Alstom. Fifty-three 9-car units were originally built for Virgin Trains from 2001 to 2004 for operation on the West Coast Main Line , with...

. There is also less wear on friction braking components. The Delhi Metro

Delhi Metro

Delhi Metro is a rapid transit system serving Delhi, Gurgaon, Noida and Ghaziabad in the National Capital Region of India. It is one of the largest metro networks in the world. The network consists of six lines with a total length of with 142 stations of which 35 are underground...

saved around 90,000 tons of carbon dioxide

Carbon dioxide

Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...

from being released into the atmosphere by regenerating 112,500 megawatt hours of electricity through the use of regenerative braking systems between 2004 and 2007. It is expected that the Delhi Metro will save over 100,000 tons of from being emitted per year once its phase II is complete through the use of regenerative braking.

Another form of simple, yet effective regenerative braking is used on the London Underground

London Underground

The London Underground is a rapid transit system serving a large part of Greater London and some parts of Buckinghamshire, Hertfordshire and Essex in England...

which is achieved by having small slopes leading up and down from stations. The train is slowed by the climb, and then leaves down a slope, so kinetic energy is converted to gravitational potential energy in the station.

Electricity generated by regenerative braking may be fed back into the traction power supply; either offset against other electrical demand on the network at that instant, or stored in lineside storage systems

Kinetic Traction Systems

Kinetic Traction Systems is a business founded in November 2010, producing energy storage systems for electric railways.-Technology:Kinetic Traction Systems' main product uses flywheel energy storage technology developed by Pentadyne Power Corp; staff from Pentadyne joined Kinetic...

for later use.

Comparison of dynamic and regenerative brakes

Dynamic brakes ("rheostatic brakes" in the UK), unlike regenerative brakes, dissipate the electric energy as heat by passing the current through large banks of variable resistor

Resistor

A linear resistor is a linear, passive two-terminal electrical component that implements electrical resistance as a circuit element.The current through a resistor is in direct proportion to the voltage across the resistor's terminals. Thus, the ratio of the voltage applied across a resistor's...

s. Vehicles that use dynamic brakes include forklift

Forklift truck

A forklift is a powered industrial truck used to lift and transport materials. The modern forklift was developed in the 1920s by various companies including the transmission manufacturing company Clark and the hoist company Yale & Towne Manufacturing...

s, Diesel-electric locomotive

Locomotive

A locomotive is a railway vehicle that provides the motive power for a train. The word originates from the Latin loco – "from a place", ablative of locus, "place" + Medieval Latin motivus, "causing motion", and is a shortened form of the term locomotive engine, first used in the early 19th...

s, and streetcar

Tram

A tram is a passenger rail vehicle which runs on tracks along public urban streets and also sometimes on separate rights of way. It may also run between cities and/or towns , and/or partially grade separated even in the cities...

s. This heat can be used to warm the vehicle interior, or dissipated externally by large radiator

Radiator

Radiators are heat exchangers used to transfer thermal energy from one medium to another for the purpose of cooling and heating. The majority of radiators are constructed to function in automobiles, buildings, and electronics...

-like cowls to house the resistor banks.

The main disadvantage of regenerative brakes when compared with dynamic brakes is the need to closely match the generated current with the supply characteristics and increased maintenance cost of the lines. With DC supplies, this requires that the voltage be closely controlled. Only with the development of power electronics

Power electronics

Power electronics is the application of solid-state electronics for the control and conversion of electric power.-Introduction:Power electronic converters can be found wherever there is a need to modify a form of electrical energy...

has this been possible with AC supplies, where the supply frequency must also be matched (this mainly applies to locomotives where an AC supply is rectified

Rectifier

A rectifier is an electrical device that converts alternating current , which periodically reverses direction, to direct current , which flows in only one direction. The process is known as rectification...

for DC motors).

A small number of mountain railway

Mountain railway

A mountain railway is a railway that ascends and descends a mountain slope that has a steep grade. Such railways can use a number of different technologies to overcome the steepness of the grade...

s have used 3-phase

Three-phase

In electrical engineering, three-phase electric power systems have at least three conductors carrying voltage waveforms that are radians offset in time...

power supplies and 3-phase induction motors. This results in a near constant speed for all trains as the motors rotate with the supply frequency both when motoring and braking.

Kinetic Energy Recovery Systems

Kinetic Energy Recovery Systems (KERS) were used for the motor sport Formula One

Formula One

Formula One, also known as Formula 1 or F1 and referred to officially as the FIA Formula One World Championship, is the highest class of single seater auto racing sanctioned by the Fédération Internationale de l'Automobile . The "formula" designation in the name refers to a set of rules with which...

's 2009 season

2009 Formula One season

The 2009 Formula One season was the 60th FIA Formula One World Championship season. The season took place over 17 rounds, and started with the on 29 March 2009. It ended on 1 November 2009 with the inaugural ....

, and are under development for road vehicles. KERS was abandoned for the 2010 Formula One season, but re-introduced for the 2011 season. As of the 2011 season, 9 teams are using KERS, with 3 teams having not used it so far in a race. One of the main reasons that not all cars use KERS is because it adds an extra 25 kilograms of weight, while not adding to the total car weight, it does incur a penalty particularly seen in the qualifying rounds, as it raises the car's center of gravity, and reduces the amount of ballast

Ballast weight

Ballast weight is something that is added to a race car to alter its performance.In most racing series, cars have a minimum weight. Often, the actual weight of the car is lower, so ballast is used to bring it up to the minimum. The advantage is that the ballast can be positioned to affect the car's...

that is available to balance the car so that it is more predictable when turning. FIA rules also limit the exploitation of the system. The concept of transferring the vehicle’s kinetic energy using flywheel energy storage

Flywheel energy storage

Flywheel energy storage works by accelerating a rotor to a very high speed and maintaining the energy in the system as rotational energy...

was postulated by physicist Richard Feynman

Richard Feynman

Richard Phillips Feynman was an American physicist known for his work in the path integral formulation of quantum mechanics, the theory of quantum electrodynamics and the physics of the superfluidity of supercooled liquid helium, as well as in particle physics...

in the 1950s and is exemplified in complex high end systems such as the Zytek

Zytek

Zytek Group Ltd is an automotive and motorsport company founded in 1981 and based in Fradley and Repton, United Kingdom. Zytek Group has two main division: Zytek Automotive, which is based at Fradley, Staffordshire; and Zytek Engineering, which is based at Repton, Derbyshire.-Zytek Automotive:Zytek...

, Flybrid, Torotrak and Xtrac used in F1 and simple, easily manufactured and integrated differential based systems such as the Cambridge Passenger/Commercial Vehicle Kinetic Energy Recovery System (CPC-KERS).

Xtrac and Flybrid are both licensees of Torotrak's technologies, which employ a small and sophisticated ancillary gearbox incorporating a continuously variable transmission

Continuously variable transmission

A continuously variable transmission is a transmission that can change steplessly through an infinite number of effective gear ratios between maximum and minimum values. This contrasts with other mechanical transmissions that offer a fixed number of gear ratios...

(CVT). The CPC-KERS is similar as it also forms part of the driveline assembly. However, the whole mechanism including the flywheel sits entirely in the vehicle’s hub (looking like a drum brake). In the CPC-KERS, a differential replaces the CVT and transfers torque between the flywheel

Flywheel

A flywheel is a rotating mechanical device that is used to store rotational energy. Flywheels have a significant moment of inertia, and thus resist changes in rotational speed. The amount of energy stored in a flywheel is proportional to the square of its rotational speed...

, drive wheel and road wheel.

History

The first of these systems to be revealed was the Flybrid This system weighs 24 kg and has an energy capacity of 400 kJ after allowing for internal losses. A maximum power boost of 60 kW (81.6 PS, 80.4 HP) for 6.67 seconds is available. The 240 mm diameter flywheel weighs 5.0 kg and revolves at up to 64,500 rpm. Maximum torque is 18 Nm (13.3 ftlbs). The system occupies a volume of 13 litres

Two minor incidents have been reported during testing of KERS systems in . The first occurred when the Red Bull Racing

Red Bull Racing

Red Bull Racing is a Formula One racing team based in Milton Keynes, England which currently holds an Austrian licence. It is, along with Scuderia Toro Rosso, one of two teams owned by beverage company Red Bull GmbH. The team have won two Constructors' Championship titles, in and , becoming the...

team tested their KERS battery for the first time in July: it malfunctioned and caused a fire scare that led to the team's factory being evacuated. The second was less than a week later when a BMW Sauber mechanic was given an electric shock when he touched Christian Klien

Christian Klien

Christian Klien is an Austrian former Formula One racing driver. In total he has scored 14 points in Formula One.Klien currently drives for Aston Martin Racing in the Intercontinental Le Mans Cup-Racing career:...

's KERS-equipped car during a test at the Jerez circuit.

FIA

Formula One

have stated that they support responsible solutions to the world's environmental challenges, and the FIA

Fédération Internationale de l'Automobile

The Fédération Internationale de l'Automobile is a non-profit association established as the Association Internationale des Automobile Clubs Reconnus on 20 June 1904 to represent the interests of motoring organisations and motor car users...

allowed the use of 81 hp KERS in the regulations for the 2009 Formula One season

2009 Formula One season

. Teams began testing systems in 2008: energy can either be stored as mechanical energy (as in a flywheel

Flywheel

) or as electrical energy (as in a battery or supercapacitor).

With the introduction of KERS in the 2009 season, only four teams used it at some point in the season: Ferrari

Scuderia Ferrari

Scuderia Ferrari is the racing team division of the Ferrari automobile marque. The team currently only races in Formula One but has competed in numerous classes of motorsport since its formation in 1929, including sportscar racing....

, Renault

Renault F1

Lotus Renault GP, formerly the Renault F1 Team, is a British Formula One racing team. The Oxfordshire-based team can trace its roots back through the Benetton team of the late 1980s and 1990s to the Toleman team of the early 1980s. Renault had also competed in various forms since , before taking...

, BMW, and McLaren

McLaren

McLaren Racing Limited, trading as Vodafone McLaren Mercedes, is a British Formula One team based in Woking, Surrey, United Kingdom. McLaren is best known as a Formula One constructor but has also competed and won in the Indianapolis 500 and Canadian-American Challenge Cup...

. Eventually, during the season, Renault and BMW stopped using the system. Vodafone McLaren Mercedes

McLaren

became the first team to win a F1 GP using a KERS equipped car when Lewis Hamilton

Lewis Hamilton

Lewis Carl Davidson Hamilton, MBE is a British Formula One racing driver from England, currently racing for the McLaren team. He was the Formula One World Champion.Hamilton was born in Stevenage, Hertfordshire...

won the Hungarian Grand Prix on July 26, 2009. Their second KERS equipped car finished fifth. At the following race, Lewis Hamilton became the first driver to take pole position with a KERS car, his team mate, Heikki Kovalainen

Heikki Kovalainen

Heikki Johannes Kovalainen is a Finnish Formula One racing driver who spent the 2008 and 2009 seasons with British based team McLaren and the 2010 and 2011 seasons with Team Lotus....

qualifying second. This was also the first instance of an all KERS front row. On August 30, 2009, Kimi Räikkönen

Kimi Räikkönen

Kimi Matias Räikkönen , nicknamed Iceman, is a Finnish racing driver, who will drive in Formula One for Lotus in . After nine seasons racing in Formula One, in which he took the Formula One World Drivers' Championship, he competed in the World Rally Championship from 2009-2011.Räikkönen entered...

won the Belgian Grand Prix with his KERS equipped Ferrari. It was the first time that KERS contributed directly to a race victory, with second placed Giancarlo Fisichella

Giancarlo Fisichella

Giancarlo Fisichella , also known as Fisico, Giano or Fisi, is an Italian racing driver. He has driven in Formula One for Minardi, Jordan, Benetton, Sauber, Renault, Force India and Ferrari. Nowadays, he drives for AF Corse's GT2 Ferrari in various sportscar events...

claiming "Actually, I was quicker than Kimi. He only took me because of KERS at the beginning".

Although KERS was still legal in F1 in the 2010 season, all the teams had agreed not to use it. New rules for the 2011 F1 season which raised the minimum weight limit of the car and driver by 20 kg to 640 kg, along with the FOTA teams agreeing to the use of KERS devices once more, meant that KERS returned for the 2011 season. This is still optional as it was in the 2009 season; as of the 2011 season 3 teams have elected not to use it.

As of 2014, the power storage of the KERS units will increase from 60 kW to 120 kW. This will be to balance the sport's move from 2.4 litre V8 engines to 1.6 litre V6 engines.

Autopart makers

Bosch

Robert Bosch GmbH

Robert Bosch GmbH is a multinational engineering and electronics company headquartered in Gerlingen, near Stuttgart, Germany. It is the world's largest supplier of automotive components...

Motorsport Service is developing a KERS for use in motor racing. These electricity storage systems for hybrid and engine functions include a lithium-ion battery with scalable capacity or a flywheel

Flywheel

, a four to eight kilogram electric motor

Electric motor

An electric motor converts electrical energy into mechanical energy.Most electric motors operate through the interaction of magnetic fields and current-carrying conductors to generate force...

(with a maximum power level of 60 kW), as well as the KERS controller for power and battery management. Bosch also offers a range of electric hybrid systems for commercial and light-duty applications.

Carmakers

Automakers including Honda

Honda

is a Japanese public multinational corporation primarily known as a manufacturer of automobiles and motorcycles.Honda has been the world's largest motorcycle manufacturer since 1959, as well as the world's largest manufacturer of internal combustion engines measured by volume, producing more than...

have been testing KERS systems. At the 2008 1,000 km of Silverstone, Peugeot Sport unveiled the Peugeot 908 HY, a hybrid electric

Hybrid electric vehicle

A hybrid electric vehicle is a type of hybrid vehicle and electric vehicle which combines a conventional internal combustion engine propulsion system with an electric propulsion system. The presence of the electric powertrain is intended to achieve either better fuel economy than a conventional...

variant of the diesel 908, with KERS. Peugeot plans to campaign the car in the 2009 Le Mans Series season

2009 Le Mans Series season

The 2009 Le Mans Series season was the sixth season of Automobile Club de l'Ouest's Le Mans Series. It was contested over five events between 5 April and 13 September 2009....

, although it will not be capable of scoring championship points.

Vodafone McLaren Mercedes

McLaren

began testing of their KERS in September 2008 at the Jerez test track in preparation for the 2009 F1 season, although at that time it was not yet known if they would be operating an electrical or mechanical system. In November 2008 it was announced that Freescale Semiconductor

Freescale Semiconductor

Freescale Semiconductor, Inc. is a producer and designer of embedded hardware, with 17 billion semiconductor chips in use around the world. The company focuses on the automotive, consumer, industrial and networking markets with its product portfolio including microprocessors, microcontrollers,...

would collaborate with McLaren Electronic Systems

McLaren Electronic Systems

McLaren Electronic Systems is a member of the McLaren Group that controls Vodafone McLaren Mercedes, a Formula One racing team and constructor....

to further develop its KERS for McLaren's Formula One car from 2010 onwards. Both parties believed this collaboration would improve McLaren's KERS system and help the system filter down to road car technology.

Toyota has used a supercapacitor for regeneration on Supra

Toyota Supra

The Toyota Supra is a sports car/grand tourer that was produced by Toyota Motor Company from 1979 to 2002. The styling of the Toyota Supra was derived from the Toyota Celica, but it was both longer and wider. Starting in mid-1986, the Supra became its own model and was no longer based on the Celica...

HV-R hybrid race car that won the 24 Hours of Tokachi race in July 2007.

Motorcycles

KTM

KTM Sportmotorcycle AG is an Austrian motorcycle, bicycle and moped manufacturer.The company was founded in 1934 by engineer Hans Trunkenpolz in Mattighofen. It started out as a metal working shop and was named Kraftfahrzeuge Trunkenpolz Mattighofen...

racing boss Harald Bartol

Harald Bartol

Harald Bartol is a former Grand Prix motorcycle road racer from Austria. His best year was in 1978 when he rode a Morbidelli to fourth place in the 125cc world championship. His best result was a second place at the 1978 125cc Austrian Grand Prix. After retiring from competition, Bartol became...

has revealed that the factory raced with a secret Kinetic Energy Recovery System (KERS) fitted to Tommy Koyama

Tomoyoshi Koyama

is a professional motorcycle road racer who currently races in the Spanish Moto2 Championship. After competing in Grand Prix races as a wild card since 2000, he joined the series full-time in 2005, with Ajo Motorsport. His best result of the season was 2nd at Phillip Island, and he also was best...

's motorcycle during the 2008 season-ending 125cc Valencian Grand Prix

Valencian Community motorcycle Grand Prix

The Valencian Community motorcycle Grand Prix is a motorcycling event held in Spain that is part of the Grand Prix motorcycle racing season. The event takes place at the Circuit Ricardo Tormo .-Multiple winners :...

. This was illegal and against the rules, so they were later banned from doing it afterwards.

Races

Automobile Club de l'Ouest

The Automobile Club de l'Ouest , sometimes abbreviated to ACO, is the largest automotive group in France. It was founded in 1906 by car building and racing enthusiasts, and is most famous for being the organising entity behind the annual Le Mans 24 Hours race...

, the organizer behind the annual 24 Hours of Le Mans

24 Hours of Le Mans

The 24 Hours of Le Mans is the world's oldest sports car race in endurance racing, held annually since near the town of Le Mans, France. Commonly known as the Grand Prix of Endurance and Efficiency, race teams have to balance speed against the cars' ability to run for 24 hours without sustaining...

event and the Le Mans Series

Le Mans Series

The Le Mans Series is a European sports car racing endurance series based around the 24 Hours of Le Mans race and run by the Automobile Club de l'Ouest . The series was originally named the Le Mans Endurance Series, but changed its name prior to the 2006 season...

is currently "studying specific rules for LMP1

Le Mans Prototype

A Le Mans Prototype is a type of sports prototype race car most notably used in the 24 Hours of Le Mans, American Le Mans Series and Le Mans Series...

that will be equipped with a kinetic energy recovery system. " Peugeot was the first manufacturer to unveil a fully functioning LMP1 car in the form of the 908 HY at the 2008 Autosport 1000 km race at Silverstone.

Use in compressed air cars

Regenerative brakes could be employed in compressed air cars to refill the air tank during braking.

The motor as a generator

Limitations

Electric railway vehicle operation

Comparison of dynamic and regenerative brakes

Kinetic Energy Recovery Systems

History

FIA

Autopart makers

Carmakers

Motorcycles

Races

Use in compressed air cars

See also