Examination of Vibration Energy Harvesting in an Automobile

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ABHISHEK BHARDWAJ VIJEET SINGH SHIVAM SHANDILYA ABSTRACT
As observed in day-to-day life, driving on the bumpy road generates vibrational energy in an automobile which is then dissipated by the shock absorbers.Thus, the vibrational energy is generally wasted in the suspension system of the vehicle.This paper deals with the analysis of various methods which can be implemented to recover the mentioned waste vibrational energy.Also, significant focus is put on the study of energy harvesting concept applied to automobiles.Two popular models of energy harvester mechanism, rotary and linear electromagnetic generator are constructed and analyzed for energy absorption and comfortability.Generally, in an automobile, shock absorber has inherited extensive use in vehicle suspensions since forty-fifty years ago to extensively lessen the acceleration of auto bodies and maintain good contact between tires and ground under road irregularities.But lately as we progress into the energy depleting, energy concern awake era, energy efficiency has been a serious concern within the automobile manufacturing industry since the production within the 1900s, researchers realized that the energy dissipated in traditional hydraulic shock absorbers is merit being recovered only within the middle of 1990s.Since then, many alternative styles of energy harvesting based shock absorbers were conceptualized and prototyped.Unlike traditional suspension systems which suppress the vibrations by dissipating the vibration energy into waste heat, the regenerative suspension with energy harvesting shock absorbers can convert the traditionally wasted energy into electricity.Several different techniques followed for the energy harvesting is listed and Two main devices namely rotary and linear electromagnetic generator is analyzed for comfort and handling, body acceleration with and without generator and also attempt is made to enunciate the importance of energy conservation techniques in an automobile.

NOMENCLATURE
F: electromagnetic force.N: number of coils Nc: number of coils Bw: magnetic flux density.Lt: length of coil turn P: number of poles B: magnetic flux density v: regenerated voltage φ: flux linkage Ms: sprung mass Mus: un-sprung mass Ks: suspension stiffness Cs : suspension damping Zs : sprung mass level,

INTRODUCTION
The main goal of the current research study is to analyze the different methods/devices to conserve vibrational energy in an automobile.The vibrational energy of the vehicle generated from driving on an uneven road and also generated from automobile acceleration/deceleration is dissipated by the shock absorbers system.Generally speaking, suspension systems is the correct term for pointing out the systems which dissipate the vibrational energy generated by driving around bumps or acceleration or deceleration happens.Not all of this generated energy gets utilized in an automobile.There will be plenty of areas where one could make use of the dissipated vibrational energy generated by suspension system devices like shock absorber, But in reality,majority of the shock absorbers just dissipate them outside from automobile, therefore the vibrational energy is wasted in the automobile.Utilizing this wasted vibrational energy can sustain energy because this generated energy can power other systems like suspension systems or other systems in an automobile and thereby conserve energy.This idea of making use of shock absorbers of a vehicle by applying electromagnetic law thereby using it to convert vibrational energy into electric energy necessary enough to drive other systems in a vehicle was proposed by Goldner in 2001.Many of the research scholar's fancy proposing a device such as regenerator for the above-mentioned task.In almost all such device designs, recovering the wasted vibrational energy was carried out using a simple electromagnetic device which is sensitive to movement.Also other ways of recovering wasted vibrational energy will be by constructing two hugely popular regenerative shock absorbers of which, one works as linear unit and other works as a rotary unit.Since this idea was proposed early 2010's soon it was shown that such two shock absorbers can recover only a small portion of vibrational energy wasted.So, quest or search for a mechanism or a device was still in progress which can recover wasted energy efficiently.The recent years researches deal more with reducing fuel consumption of the vehicle so that lost vibrational energy is less.Due to recent developments obtained in permanent magnet and microelectronic systems these enable the possibility of actual implementation of electromagnetic mechanism to recover vibrational energy and improve the performance of vehicle suspension systems.One such device is an electromagnetic harvester which helps in recovering this wasted energy also helps in reducing fuel consumption by reducing energy wastage.Researches on electromagnetic vibration energy recovery model were investigated and was found out that a micro electromagnetic generator can deliver 30% of power from environment to useful power.Generally, best way to install energy harvesters is by the two popular commonly available designs ie; linear and rotary regenerator.In our case, rotary or linear electromagnetic generator will operate as energy recovery devices and thereby will help in energy conservation and recovering lost vibrational energy.

METHODOLOGY Electromagnetic Generator
Electro-magnetism technology [Zuo et al,2015] is in use for generating electricity since 1930's shortly after Faraday's fundamental breakthrough in electromagnet induction.When an electrical conductor is moved through a flux, a possible difference is induced between ends of conductor.The voltage induced in circuit is proportional to time rate of change of magnetic flux linkage of the circuit, is expressed as: In most of applications, the circuit usually consists of coils of wire with multiple turns and also the forcefield generated with permanent magnets, that the voltage induced are given by the formula V = -N d ?/d? (2) Flux linkage for multiple coil is evaluated becausethe sum of the age of individual flux, is mostly associated with the vehicle's comparatively and low frequency compression and rebound moments as a response to the bumps on the road following the un-damped suspension (i:e; without the shock absorbers in an vehicle) can expertise a series of oscillation that may cycle in keeping the natural frequency of the system.Where B is magnetic flux densities the realm of i th turn.To extract power form generator the coil terminal must be connected to a load resistance allowing a current to flow within the coil.Interaction between the sector caused by induced current to field form the magnet create to a force which opposes the motion and is proportional to this and therefore the velocity F= D dx/dt (4) Maximizing the facility within the variety of current involves maximization of electromagnetic damping demonstration.The instantaneous power can be expressed as P = F dx/dt (5)

Vehicle Comfort and Handling
One of the most terms in automobile is quality which is remarked as ride comfort [Longxin et al,2010] and is suffering from a several factors, like high frequency vibrations, body booming, body roll and pitch, further because the vertical spring actions normally related to a smooth ride.If the vehicle conditions are noisy, if it rolls out excessively in turns, or lurches and pitches during the acceleration or the braking, or if the body produces a booming resonance, possibly passengers will experience an uncomfortable ride.The ride quality is mostly associated with the vehicles comparatively low frequency compression and rebound movements as a response to the bumps on the road.Following a bump, the un-damped suspension of a vehicle can expertise series of oscillations that may cycle in keeping with the natural frequency of the system.Ride is perceived as most comfy once the natural frequency is within the vary of regarding one-hz to 1.5Hz.once the frequency approaches 2Hz, occupants understand the ride as harsh.As ISO commonplace, Root Mean sq.(RMS) of acceleration is beneath 0.315 m/s2.international signal statistics accustomed summarize the acceleration time histories embody the basis Mean sq.(RMS) worth outlined as: ?() = [?]1/[?]2(?)? (6) Shock absorber damping is additionally touching vehicle handling.Compression damping is that the damping that a shock provides as it is being compressed, for example once driving over a bump on the road.If the compression damping is just too low, the wheel can lose contact with the road and management over the automotive is lost.If the compression damping is just too high, the road unevenness is transmitted directly through the chassis of the automotive, which ends up during a very harsh ride.Rebound damping is that the damping that a shock provides because it returns from its compressed state to its equilibrium state.a coffee rebound damping results in a awfully soft ride.A high rebound damping prevents the wheel from returning to its equilibrium state when a bump, that causes it too loose contact with the road.Vehicle DampersAutomotive dampers normally called shock absorbers square measure utilized in vehicle suspension systems to isolate the vehicle chassis from unwanted vibrations thanks to the road disturbances, and to supply smart road handling.The idea of linear damper that generates force proportional to its endings relative rate is wide used and studied in vibration analysis.Dampers are developed over the history of engineering from straightforward friction dampers to trendy telescopic ones.Hydraulic damper is usually used that absorbers suppress vehicle frame vibration by a piston moving through oil.Holes within the piston square measure lined by valves, that resist the flow of the oil through the holes during a controlled manner to supply the damping impact.it's converted the energy of the vibration into heat; therefore, this energy is dissipated.mistreatment magnetism dampers [Zhang et.al,.2020](composed of mechanical device elements), the mechanical energy of car body vibration are often regenerated as helpful electricity.At first all the primary the parameters of car were determined.Vehicle is modelled and analyzed quarter automobile.At the second we tend to style rotary and linear magnetic attraction energy harvester.Model is diagrammatically as state area equation.All of model is simulated and compared thanks to comfort by analyzing vibration transferred to traveler and quantity of energy absorption by analyzing power output of generator.where: b1 is damping of gear rack, k1 is stiffness of gear rack, Fc is tangential force, J1 is Inertia of gear rack, θ1 is angular displacement of gear rack, θ2 is angular displacement of electromagnetic harvester, b2 is damping of electromagnetic harvester, k1 is stiffness of electromagnetic harvester, J2 is Inertia of gear rack.From Equation 7 until 12 we can arrange into state space form as Equation 13 : Regenerated energy is represented by Equation 14.

Rotary Electromagnetic Generator
where Cem = 2NBLrccos with N is number of turn electromagnetic turn wire, B is magnetic flux density, l is length of electromagnet coil and re is diameter of rotary.[Mohamed et al,2018] The linear generator [Mohamed et al,2018] consists of 2 parts: primary give three-phase winding placed within the slots of primary core, and secondary give permanent magnets connected to the iron core that delineated as Figure two.during the oscillation of the vehicle, the secondary half is moving with regard to the first half.thanks to the relative linear motion of primary and secondary permanent magnets, Associate in Nursing AC voltage is induced within the coils.This voltage is then corrected by the 3-phase controlled convertor and provides A battery.The electrical model of magnetic force cushion connected to vehicle is shapely.The winding parameters rely on the voltage of the accumulator and on the damping force that the generator delivered to perform.so as to transmit the facility from the generator to the battery, the road electromotive force E, induced within the winding, should be larger than the voltage of the accumulator Va.The part electrical phenomenon is proportional to the linear speed v : with generator constant:

Linear Electromagnetic Suspension Generator
The generated electromotive force at steady state condition is: Since damping force is Fem = KI can be write in term of the speed, resistance and the voltage source as: This shows that electromagnetic damper has viscous properties as well good damping properties.

RESULTS
After simulation, the various research in this field has proven that with the use of energy harvester mechanism such as linear or rotary electromagnetic generator, there is great improvement in comfort and handling as well as energy being wasted is reduced greatly.

CONCLUSION
The suspension is a very important a part of the vehicle chassis and plays a key role in supporting the body and absorbing vibrations caused by rough road.The mechanical system energy harvester is that the complement for the onboard alternator, and therefore the harvested vibration energy can charge the vehicle battery and supply power for the relevant load.In the times when energy is getting depleted, there is a concern to look for the ways to conserve the energy.In order to achieve this goal, there are several ways by which one could successfully energy harvest in an automobile.Some of the conclusions which can be highlighted after thorough research on current topic is listed below: • There are several ways harvesters which can used for energy conservation.But the electromagnetic energy harvesters are more popular and heavily used in vehicle suspension systems with the intention of vibration energy harvesting because of their properties like higher energy conversion efficiency, compact structure, fast response velocity, and strong controllability • It is worth to conclude that compared to automobile systems with no mechanisms to recover wasted vibrational energy, systems with energy harvesting have proven more efficient and more comfortability and handling.• Also, electromagnetic advances have made it possible to implement these modifications to the current automobile so that energy can be conserved and most of the energy wasted can be converted for generating power to drive other systems in an automobile.• Both of energy harvester increase comfort and vehicle handling than conventional suspension.Linear electromagnetic shock absorber harvests much of energy compared to other methods of recovering energy or energy generation.Besides of this, it also makes vehicle more comfort and good in handling.But there is more complexity in construction.

Fig 1 .
Fig 1. Rotary Electromagnetic Generator [Mohamed et el,2018] In an Vibration harvesting energy with rotary electromagnetic suspension [Mohamed et al,2018] The dynamic equation at sprung mass is given as :