3 Seminar

K.E.R.S and D.R.S in Formula 1 2013

1. Kinetic Energy Recovery System

Dept. of mechanical engg. H.K.B.K.C.E Page 1


ABSTRACTA moving train contains energy, known as kinetic energy, which needs to be removed from the train in order to cause it to stop. The simplest way of doing this is to convert the energy into heat. The conversion is usually done by applying a contact material to the rotating wheels or to discs attached to the axles. The material creates friction and converts the kinetic energy into heat. The wheels slow down and eventually the train stops. The material used for braking is normally in the form of a block or pad.The vast majority of the world's trains are equipped with braking systems which use compressed air as the force used to push blocks on to wheels or pads on to discs. These systems are known as "air brakes" or "pneumatic brakes". The compressed air is transmitted along the train through a "brake pipe". Changing the level of air pressure in the pipe causes a change in the state of the brake on each vehicle. It can apply the brake, release it or hold it "on" after a partial application. The system is in widespread use throughout the world. An alternative to the air brake, known as the vacuum brake, was introduced around the early 1870s, the same time as the air brake. Like the air brake, the vacuum brake system is controlled through a brake pipe connecting a brake valve in the driver's cab with braking equipment on every vehicle. The operation of the brake equipment on each vehicle depends on the condition of a vacuum created in the pipe by an ejector or exhauster. The ejector, using steam on a steam locomotive, or an exhauster, using electric power on other types of train, removes atmospheric pressure from the brake pipe to create the vacuum. With a full vacuum, the brake is released. With no vacuum, i.e. normal atmospheric pressure in the brake pipe, the brake is fully applied.



INTRODUCTION

KERS means Kinetic Energy Recovery System and it refers to the mechanisms that recover the energy that would normally be lost when reducing speed. The energy is stored in a mechanical form and retransmitted to the wheel in order to help the acceleration. Electric vehicles and hybrid have a similar system called Regenerative Brake which restores the energy in the batteries.The device recovers the kinetic energy that is present in the waste heat created by the car’s braking process. It stores that energy and converts it into power that can be called upon to boost acceleration.

There are principally two types of system - battery (electrical) and flywheel (mechanical). Electrical systems use a motor-generator incorporated in the car’s transmission which converts mechanical energy into electrical energy and vice versa. Once the energy has been harnessed, it is stored in a battery and released when required.

Mechanical systems capture braking energy and use it to turn a small flywheel which can spin at up to 80,000 rpm. When extra power is required, the flywheel is connected to the car’s rear wheels. In contrast to an electrical KERS, the mechanical energy doesn’t change state and is therefore more efficient.

There is one other option available - hydraulic KERS, where braking energy is used to accumulate hydraulic pressure which is then sent to the wheels when required.



CONSTRUCTION DETAIL

1. Mechanical type

The first, mechanical, consisted of using a carbon flywheel in a vacuum linked via a CVT transmission to the differential. This system stores the mechanical energy, offers a big storage capacity and has the advantage of being independent from the gearbox. However, to be driven precisely, it requires some powerful and bulky actuators, and lots of space. Compared to the alternative of electrical-battery systems, the mechanical KERS system provides a significantly more compact, efficient, lighter and environmentally-friendly solution.The components within each variator include an input disc and an opposing output disc. Each disc is formed so that the gap created between the discs is ‘doughnut’ shaped; that is, the toroidal surfaces on each disc form the toroidalcavity. Two or three rollers are located inside each toroidal cavity and are positioned so that the outer edge of each roller is in contact with the toroidal surfaces of the input disc and output disc. As the input disc rotates, power is transferred via the rollers to the output disc, which rotates in the opposite direction to the input disc.The angle of the roller determines the ratio of the Variator and therefore a change in the angle of the roller results in a change in the ratio. So, with the roller at a small radius (near the centre) on the input disc and at a large radius (near the edge) on the output disc the Variator produces a ‘low’ ratio. Moving the roller across the discs to a large radius at the input disc and corresponding low radius at the output produces the ‘high’ ratio and provides the full ratio sweep in a smooth, continuous manner.The transfer of power through the contacting surfaces of the discs and rollers takes place via a microscopic film of specially developed long-molecule traction fluid. This fluid separates the rolling surfaces of the discs and rollers at their contact points.The input and output discs are clamped together within each variator unit. The traction fluid in the contact points between the discs and rollers become highly viscous under this clamping pressure, increasing its ‘stickiness’ and creating an efficient mechanism for transferring power between the rotating discs and rollers.The second option, electrical, was to rely on an electrical motor, which works by charging the batteries under braking and releasing the power on acceleration. This system consists of three important parts:1. An electric motor (MGU: Motor Generator Unit) situated between the fuel tank and the engine, linked directly to the crankshaft of the V8 to deliver additional power.2. Some latest generation ion-lithium batteries (HVB: High Voltage Battery Pack) capable of storing and delivering energy rapidly.3. A control box (KCU: KERS Control Unit), which manages the behavior of the MGU when charging and releasing energy. It is linked to the car’s standard electronic control unit.In essence a KERS systems is simple, you need a component for generating the power, one for storing it and another to control it all. Thus KERS systems have three main components:



The MGU, the PCU and the batteries. They are simply laid out as in the diagram below:

MGU (Motor Generator unit)

Mounted to the front of the engine, this is driven off a gear at the front of the crankshaft. Working in two modes, the MGU both creates the power for the batteries when the car is braking, then return the power from the batteries to add power directly to the engine, when the KERS button is deployed. Running high RPM and generating a significant Dc current the unit run very hot, so teams typically oil or water cool the MGU.

Fig. Marelli MGU as used by Ferrari and Renault

Flywheel technology by Williams Hybrid power

WHP has taken the electrically powered integral motor - effectively a flywheel with integrated motor - design and radically improved its performance characteristics by incorporating Magnetically Loaded Composite (MLC) technology. The MLC technology was developed in the nuclear industry by Urenco and has been licensed by WHP.

In WHP’s Magnetically Loaded Composite Flywheel Energy Storage System (MLCFESS), the permanent magnets of the integral motor are incorporated into the composite structure of the flywheel itself. In the event of a burst failure, the containment has to withstand only the crushing force of the composite material, which is less than the load of discrete metallic fragments. The reduced containment requirements minimize the overall weight of the system. The magnetic particles in the composite are magnetised after the rotor is manufactured which means that it can be magnetised as a Halbach Array; avoiding the need for backing iron to direct the flux.



As the magnets in an MLC system are comprised of tiny magnetic particles and there is no additional metal in the structure, the eddy current losses of the machine are significantly reduced. This can result in one-way efficiencies of up to 99%. The ultra-high efficiency means thermal management of the system is easier and it can be continuously cycled with no detriment to performance or reduction in life.

Its final version for Formula One will have a high specific power of more than 5kW/kg which is possible by spinning the wheel to more than 50000rpm. Even more so, because the system is fully contained and doesn't require an external motor, it is probably the most compact F1 KERS solution and proves suitable for volume production to other appliances.

Chemical batteriesExcept for Williams, all Formula One teams have taken the route of chemical batteries to store the recoverable energy. Despite the flywheel's advantages, the short life cycles in Formula One and the limitless search for miniaturisation have made teams decide on batteries. The best known supplier of such a system is Magnetti Marelli who presented their system to the public in November 2008. It features an electric motor that can work as an alternator to convert motion energy to eletrical as well as the other way around to release previously stored energy to the wheels.

Additionally, the motor also has a built in water cooling system. It is then up to the teams to design an effective cooling system with the least possible drag penalty. Not such an easy task considering the stringent rules on cooling apertures. The Italian firm is however sure that in the medium term it will be able to increase the motor's efficiency and hence reduce its cooling requirements.



Several teams will be using this system, including Ferrari and Scuderia Toro Rosso. Because of Magnetti Marelli's expertise with electronics, the resulting motor and accompanying KERS control unit weighs as low as 4kg.

The actual energy storage device is left up to the teams to design. Magnetti Marelli had initially planned to design such package but quickly realised that teams had very different demands in this area, hence leaving it up to them to create the energy storage systems. It appears that most teams will be using lithium-ion batteries as supercapacitors weigh far too much to be useful in Formula One - estimated at 300kg to equal the 40kg flywheel solution of Williams Hybrid drive.

PCU (Power Control Unit)

Typically mounted in the sidepod this black box of electronics served two purposes, firstly to invert & control the switching of current from the batteries to the MGU and secondly to monitor the status of the individual cells with the battery. Managing the battery is critical as the efficiency of a pack of Li-ion cells will drop if one cell starts to fail. A failing cell can overheat rapidly and cause safety issues. As with all KERS components the PCU needs cooling.

Fig. Marelli prototype PCU



2. Hydraulic KERS

A further alternative to the generation and storage of energy is to use hydraulics. This system has some limitations, but with the capped energy storage mandated within the rules the system could see a short term application. Separate to the cars other hydraulic systems, a hydraulic KERS would use a pump in place of the MGU and an accumulator in place of the batteries. Simple valving would route the fluid into the accumulator or to the pump to either generate or reapply the stored power. Hydraulic accumulators are already used in heavy industry to provide back up in the event of failure to conventional pumped systems.Using filament wound carbon fibre casing, an accumulator of sufficient capacity could be made light enough to fit into the car .

They might be capped in terms of practical storage with in the confines of an F1 sized system, but McLaren had prepared just such an energy recovery system back on the late 90s, but it was banned before it could race. With the relatively low FIA cap on energy storage, just such a system could be easily packaged, the hydraulic MGU would be sited in the conventional front-of-engine position and the accumulator, given proper crash protection fitted to the sidepodfuel tank area. Saving space would be minimal control system (equivalent to the PCU) as the valving to control the system could be controlled by the cars main electro hydraulic system. McLaren have recently been quoted as saying the 2011 KERS would be more hydraulic and less electronic. Giving rise to speculation that a hydraulic storage system could be used.



Fig. Hudraulic KERS System



KERS IN FORMULA 1

The FIA (Federation InternationaleL"Automobile) have authorized hybrid drivetrains in Formula 1 racing for the 2009 racing season. The intent is to use the engineering resources of the Formula 1 community to develop hybrid technology for use not only in motorsport but also eventually in road vehicles. The hybrid systems specifications have been kept to a minimum, especially the type of hybrid system. This was done purposely to lead to the study and development of various alternatives for electrical hybrids which has been met with success. Kinetic Energy Recovery Systems (KERS) were used for the motor sport Formula One's 2009 season, and under development for road vehicles. Its is being mainly used by Ferrari, renault, BMW and Mc laren. Tt raises the car's center of gravity, and reduces the amount of ballast that is available to balance the car so that it is more predictable when turning. physicist Richard Feynman postulated the theory of transferring the vehicleâ„¢s kinetic energy using the method of Flywheel energy storage. Zytek, Flybrid, Torotrak and Xtrac are the conventional systems available.

Use in motor sportHistoryFlybrid was the first system to be revealed. It weighed 24 kg and has an energy capacity of 400 kJ . It could provide a power boost of power boost of 60 kW .

FIAFIA allowed the use of 81 hp KERS with some regulations. energy can either be stored as mechanical energy in a flywheel or in a battery or supercapacitor as electric energy.

Autopart makersBosch Motorsport Service is an active developer of KERS for motorsports. lithium-ion battery , flywheel, capacitor etc are used to store energy.

CarmakersMany manufacturers like Honda has been testing KERS systems. Peugeot 908 HY is an Hybrid vehicle with KERS.

MotorcyclesKTM racing used a motorcycle with Kinetic Energy Recovery System (KERS) fitted to Tommy Koyama's motorcycle during the 2008. It was illegal and they were warned.



Safety ConceptSafety concept concerning Control System is following:Control unit limits rotational speed by a hardware lock in the output stage. Controlsystem monitors all security parameters. During idle operation is no voltage induced.In case of error messages or breakdown, control system discharge KERS.Controlled and safe discharge of the system is possible by converting rotational energyin thermal energy. In the flywheel storage system, the critical energy is reduced byusing several small storages, coolant ducts and channels in stator [Fig. 14.], [Fig. 15.].FES is designed as a reluctance motor and its resulting safety benefits arefollowing:Inner flywheel rotor is designed as homogenous flywheel mass without any additionalcoil former, windings, magnets or rotor cage. Laminated rotor consists of sheetmetalpacket, incl. disc spring and rotor shaft equipped with hybrid bearing [Fig. 17.].





Case study

During the EVS 25 electric vehicle expo in Shanghai earlier this months, Honda engineers presented a glimpse into the development of an advanced high-performance electric motor that Honda had designed as part of a KERS (Kinetic Energy Recovery System) intended for its 2009 Formula One race car.

Fig 2009 Honda Formula One chassis configuration, showing KERS component location.

KERS (Kinetic Energy Recovery System) regenerative braking systems are limited to storing up to 400 kilojoules of energy per lap, which can then be released at up to 60 kW (80 hp) for up to 6.67 seconds as part of a “push-to-pass” strategy. Depending on track design, this can increase vehicle acceleration by up to 15 kilometers per hour, gaining up to 20 meters of distance per lap.

However, KERS systems present significant design challenges in that they must be implemented without adversely affecting vehicle aerodynamics, weight, weight distribution, collision safety, fuel tank capacity, or center of gravity. Honda engineers decided to implement an electric motor/battery pack solution, rather than a flywheel solution, mounting the motor on the engine’s left front side with its power control unit (PCU) ahead of it, inside the monocoque chassis.

The motor was cooled by engine oil and the PCU was cooled by a dedicated coolant loop. The 106-cell lithium-ion battery pack was mounted in the forward section of the vehicle’s keel to preserve the vehicle’s center of gravity and take advantage of draft air cooling.

Given the light weight (minimum 620 kg/1,367 pounds) and compact design of Formula One cars, Honda calculated that the motor would have to be no more than 100 mm (4 inches) in diameter, 200 mm in length, and produce approximately 8 kilowatts (kW) per kilogram (almost 5 hp per pound) of motor weight. By comparison, a typical mass production hybrid or electric vehicle motor produces between 1.0 and 2.5 kW per kilogram.



Stator Core. A three-phase, four-pole, twelve-tooth design with a double lap-wound stator and permanent magnet rotor was selected. Operating motor speed would be roughly equivalent to engine speed, with a range of 13,000 to 21,000 rpm (engine speed was limited to 18,000 rpm during the 2009 F1 season).

An initial concern, particularly given the high motor speed, was the effect of iron losses in the stator core, which is typically an AC motor’s heaviest component. Conventional grain-oriented silicon steel was not efficient enough to be used in a motor that would meet the project’s motor size and weight targets, and an iron-cobalt alloy (49Fe-49Co-2V) was used to produce the motor’s stator core laminations. This yielded a 30% increase in flux density and a 15% increase in torque.

The iron-cobalt alloy’s iron losses were further reduced via a combination of technologies. A post-rolling heat treatment reduced core hysteresis losses, and an ultra-thin oxidized insulation coating was developed, which allowed the engineers to reduce stator core lamination thickness to a tenth of a millimeter per lamination while preserving the desired iron-to-insulation ratio. These refinements reduced the alloy’s iron losses by a further 60%.

Fig The magnetic flux density of Honda’s iron- cobalt alloy was increased through multiple refinements.

Although Honda has not released details of the motor control strategy, the maximum current frequency for a 21,000 rpm four-pole motor, assuming an equal number of poles in both rotor and stator, is 700Hz, and pulse width modulated voltages driving a motor at such a speed must inherently use extremely fast transients, creating voltage stresses within the winding. Not surprisingly, the stator winding was wound with scratch-resistant inverter duty wire to reduce the possibility of pinholes created during the manufacturing and/or winding process, and therefore reduce the possibility of winding failure.



Rotor Design. Honda developed a high-coercivity magnet with an intrinsic coercivity of at least 1.1 Ma/m at 160ºC (320ºF), and tuned the magnetization angles for maximum torque. To minimize temperature increases and resultant eddy current losses, 448 magnets (28 axially, 16 circumferentially) were used in the rotor’s interior PM configuration.

Rotor diameter was reduced by employing the rotor’s shaft as part of the rotor flux circuits. A high tensile filament winding made of organic high-strength fibers encloses the rotor, preventing magnet burst at the centrifugal forces produced at the rotor’s 21,000 rpm redline. The rotor’s ceramic ball bearings were lubricated by high-temperature grease rather than oil, to simplify the oil circuit and reduce losses.

A water-cooled motor was initially developed, but could not meet Honda’s size/performance targets. The final motor was cooled by engine oil, with stator cooling passages around the circumference of the rotor and the rotor cooled by oil passing through its hollow shaft. A thin cylindrical resin sleeve structure was mounted in the motor’s rotor-stator air gap to isolate stator cooling oil from the rotor and eliminate windage losses.

Fig Section view of motor, showing rotor and stator coolant flow paths; engine oil is used as coolant



Implementation and testing. Motor torque was delivered to the engine’s crankshaft via a front-mounted five-gear gearbox. Vehicle testing commenced in April 2008 with straight course accelerations, and progressed into circuit tests at Silverstone the following month. Additional circuit tests were conducted at full load in September, at the Jerez circuit in Spain, yielding the following results:

Lap times were reduced by ~0.4 seconds per lap at full assist; Speed was increased by 7 km/h, resulting in a gain of 7.8 meters (1.6 car lengths) on a

straightaway with a continuous 324 kJ of assist.

The final design achieved 7.8 kW (10.46 hp) of power per kilogram, close to Honda's design goal of 8 kilowatts per kilogram. Peak motor efficiency was 99% and peak generator efficiency during regen was 93%. Motor weight was 6.9 kilograms.

Fig Front-mounted gearbox, which transfers motor torque to the engine crankshaft.

KERS systems were introduced to Formula One during the 2009 racing season, and were key to several race wins, but were subsequently withdrawn due to development issues. KERS is expected to return to F1 in 2013, concurrent with the introduction of new engine regulations. Honda sold its Formula One team to Brawn GP Limited in 2009.



CONCLUSION

Comparison with other storage technologies

In comparison with other battery storage technologies, KERS offers:• Cycle durability [Fig. 25.] - 90% efficiency of flywheel (including power electronics)in both directions during KERS reference duty cycle.• Extensive operating temperature range [Fig. 26.].• Steady voltage and power level [Fig. 27.], which is independent of load, temperatureand state of charge.• High efficiency at whole working speed range.• No chemistry included, thus no environmental pollution and great recyclingcapability



2.Drag Reduction System



Abstract

This system was introduced in Grand Prix racing to facilitate overtaking. The rear wing of an F1 car is designed to generate downforce (pushing the car down) but as a consequence it also produces massive turbulence called drag. And drag reduces the top speed of the car.

The DRS allows the flap of the rear wing to move horizontally, reducing drag, increasing top speed and therefore facilitating the passing manoeuvres.



Introduction

Moveable aerodynamic components are nothing new, every time you sit on an airliner you see the wing flaps, ailerons moving around, and often as you come into land you can see the array of hydraulics employed to move them. The systems on a Formula 1 car work in essentially the same way. Hydraulic tubes, rods and actuators. But whilst on an Airbus A320 or even a modern UAV or fighter jet there is a huge amount of space to work in, on a grand prix car the opposite is true.

None the less grand Prix drivers have a new tool at their disposal, the so called Drag Reduction System, DRS. It is essentially an adjustable rear wing which can be used to facilitate overtaking.Under the rules for 2011, the driver of a following car can adjust the flap of his rear wing under certain circumstances. When two or more cars pass over timing loops in the surface of the track, if a following car is measured at less than one second behind a leading car it will be sent a signal that will allow its driver to deploy the car’s active rear wing. The flap is lifted up at the front and pivots about a point at the trailing edge of the wing, so that in the event of a failure, the flap will drop down into the default, high-downforce position. Since the timing loops will be sited after corners, drivers will only be able to deploy the active rear wing as a car goes down a particular nominated straight, in Melbourne for example this was the starting straight.



WORKING

‘As a car comes out of a corner and crosses the timing line within the prescribed interval, at the moment the following driver feels he is no longer traction limited, he will press the button and drag on his rear wing will be reduced,’ explains Tony Purnell an FIA advisor involved in the creation of the regulation. ‘He will sprint down the straight and, by the end of it, will have a 4-5kph advantage over the car he is trying to pass. When we looked at the problem in 2007, we saw that as a Formula 1 car comes out of a corner it has tremendously good acceleration – they wouldn’t be F1 cars without it – so when the leading driver gets on the throttle those fractions of a second earlier, even if the following car is a lot faster the leading car pulls a big gap. That means immediately coming out of a corner, any advantage from drag reduction is not really there.

Exactly how teams have approached the problem of actuating the wing itself is difficult to be sure of though some run tubing up through the central wing supports or through the end plates, though neither have an especially large cross sectional area to run pipework or rods. Looking at some of the front wing end plate devices used in F1 recently hydraulic lines are run to a small actuator, whilst on others an electronic actuator is used. Negating the need for a hydraulic system.Exact costs are hard to come by but the time taken to construct a cars pipework at a specialist such as FHS Motor Racing is a good indication “it is almost how long is a piece of string trying to work out how long it would take, if we take a simplistic approach & just say how long to



assemble a set of hoses then we are talking “ very” approximately 35/40 hours” explains Peter Hughes the firms MD.

“F1 teams will typically design the assembly themselves then send the files over to us to see it it is actually possible to make. We take the design files and convert them into something that’s workable. Many of the teams have worked with us for years though and know what is possible. Things like bend radius or whether something is suitable for Swaging or similar. Then as a system is being developed we go on site with the client and do mock ups to ensure it all fits.”

The materials used in these systems also require great precision and a healthy budget as Hughes explains “today in F1 it is mainly titanium tube, though some of what we do involves PEEK mainly in the fuel system but primarily titanium. Aluminium and stainless steel are also used. Titanium is favoured for its inherent lightness and strength, it means you can, make the cross section of the material so much thinner than if you were using Almuminium.

Despite the ongoing pressure on top flight motor racing to cut costs, new regulations, such as the switch from adjustable front wing to adjustable rear inevitably increase expenditure, and although the actuation systems are similar in operation little if anything can be carried over. “There is very little carry over, there are move to try and change that, so they can use last years on this years but that goes completely against the grain of the way engineers think, better lighter, car dimension changes make huge differences to use. A simple example is the car fuel filler cap – that’s one of our systems” continues Hughes.



TYPES Of DRS

Drag Reduction Systems are of two types :-

1. Single DRS

In this system drag is reduced by the movement of the rear wing alone.

The horizontal elements of the rear wing consist of the main plane and the flap. The DRS allows the flap to lift a maximum of 50 mm from the fixed main plane. This reduces opposition (drag) to airflow against the wing and results in less downforce. In the absence of significant lateral forces (straight line), less downforce allows faster acceleration and potential top speed, unless limited by the top gear ratio and engine rev limiter. Sam Michael, technical director of the Williams team (as of early 2011), believes that DRS in qualifying will be worth about half a second per lap.

The DRS is expected to offer 10–12 km/h more speed by the end of the activation zone.[3] The effectiveness of the DRS will vary from track to track and to a lesser extent from car to car. The system's effectiveness was reviewed in 2011 to see if overtaking can be made easier, but not to the extent that driver skill is sidelined. The effectiveness of DRS seems likely to be determined by the level of downforce at a given circuit (where the cars are in low drag trim at circuits like Monza, the effects may be smaller), by the length of the activation zone and by the characteristics of the track immediately after the DRS zone.


http://en.wikipedia.org/wiki/Drag_reduction_system#cite_note-3

http://en.wikipedia.org/wiki/Williams_F1

http://en.wikipedia.org/wiki/Technical_director

http://en.wikipedia.org/wiki/Sam_Michael

http://en.wikipedia.org/wiki/Rev_limiter

http://en.wikipedia.org/wiki/Gear_ratio


2 Double DRS

Red Bull experimented with a passive double drag reduction system (DDRS). The top red arrow in this drawing indicates the small inlet duct that - above a certain speed - feeds airflow up a vertical channel to blow under the rear wing's main plane. This partially stalls the wing, leading to a reduction in drag and thus a small speed increase.



Conclusion

There has been a mixed reaction to the introduction of DRS in Formula One amongst both fans and drivers. Some believe that this is the solution to the lack of overtaking in F1 in recent years while others believe this has made overtaking too easy.[4] The principal argument for the opponents of DRS is that the driver in front does not have an equal chance of defending his position because they are not allowed to deploy DRS to defend. The tightening up on the rules for a leading driver defending his position has added to this controversy


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