designing and manufacturing of formula hybrid ieee

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Designing and manufacturing of Formula SAE-Hybrid racecar for a new engineering education

programIkwhang Chang\ Namwook Kim, Daeheung Lee, Suk Won Cha

lGraduate schoo of conversion science d technoogy, Seou Nationa University, Gwana-r0599, Gwana-gu, Seou, Korea151-744

2Deptment of mechica ad aerospace engineering , Seou Nationa University, Gwa-r0599, Gwa-gu, Seou, Korea151-744

b This paper addresses the preparation andparticipation of new collegiate design series "Formula SAEhybrid (FSAE-Hybrid) under society of automotive engineers(SAE). These participation processes of FSAE-Hybrid arerequired various engineering knowledge as well as practical skillsin terms of the design engineering education in university. Thecar is built in an open-wheel, single seat, plug-in hybrid racecar.The design issues of FSAE-Hybrid emphasize powertraininnovation and fuel eciency in high hybrid power management.It is next generation vehicle, even though base model of FSAEHybrid is based on FSAE regulations and rules. Also, the severalprocesses of competition, design, cost, and sale presentation,required the team management and team-work for universitystudents. Students would utilize the software (CATIA and Pro-E)of computer-aided design in order to design chassis andsuspension, including especially upright. Based on a design partand a frame, they should analyze stress distribution of each partand ow visualization of intake as well as exhaust. Also, theintegrated vehicle is simulated by estimating the estimation offuel-economy of hybrid management (supervisory control logic)

via Matlab/Simulink and vehicle dynamics via Adams program.

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I. NTRODUCTION

The Foua SAE-Hybrid (FSAE-H) competition wasfoded by Thayer schoo of engineering at Dartmouth in 7,and endorsed om not ony the Society of AutomotiveEngineers (SAE), but aso om Institute of Eectrica adEeconics Engineers (IEEE). Many coegiate design series ofSAE are Mini Baja, Foua SAE, and supeieage. Amongthese competitions, the most interesting competition is FouaSAE. However, e paadigm of next generation vehice israpidy chged om a ICE vehice to eectric vehice and ae ce c. Therefoe, recenty, Dou coege orgaizeda vehice competition of a new concept wi hybrid powersources. e ca of FSAE-H is basicay one-seat, open whee,and racec wi hybrid power soces of a ICE d eectric motor. e main requirements of competition aeengineering knowedge, fabrication skis, ad teawork:Computer Aided Design (CAD) Computer Aided Engineering(CAE), d tea magement. Specicay, this competitiongives engineering students opportuni of muti-discipinayaea in a pug-in hybrid c. Aso, it promotes engineering

knowedge of hybrid car d powertrain. Engineering coreissues of competition ae as foows[ 1]:

High power eeconics such as motors,

generators, controers, ad DC/DC convertors Mechaica system incuding suspension, braing,

chassis, design ad ergonomics

Computerized system contro

Data acquisition

Intea combustion engines incuding inte dexhaust pts, e deive systems ad enginemapping

Project management

Regenerative braing systems

The specic events of competition divide ino two pes:static events ad dynamic events. The static event consists ofdesign d sae presentations. A tes shoud submit predesign report for design event before competition paricipation.This report generay incudes the design concept of their ca,core tecnoogy, and engineering aaysis. Based on is report,design judges ask a ot of questions to team members reating

to basic vehice design and technoogy in design events. Mostof a, te members shoud respond questions of judges wein order to get a high score. And individua tea inoduces tooer judges why their car has high vaue for pchasing.Ding this event, each te shoud necessariy prepe much

visua infoation such as saes promotiona video adbroche Aso the dynamic events consist of acceerationskid-pad, and endce race. First of a, e acceerationevent meases the acceeration perfoace of main power ineighty meter. Generay, average time is 4-mid seconds. Inorder to have a good score, iver shoud contro the tire

traction in initia driving, shiing time d so on. Secondy, thecoering abiity of vehice is measured in skid-pad eventwhich is to drive circua path. Each car reveas the steeringpropensities: oversteering d dersteering. Because thecoering abiity is a core issue in racec, my teams focuson vehice stabii d weigh disibution to improve


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Fig. 1. Concept design for a new raceca

perfoce. Finay, vehices rns endurce race withother cs. ese cas, prototype vehices, ae ve dicut tonish endace race, d ony one-third of cas come in tonish ine.

II. PTION

A Team GroupingMost of a, to mufacte a vehice, team members ad

congurations need to be desied we. Because themufacting processes, especiay chassis d suspension,require interactive teawork, a tea eader considers eimportace of ha management: how many parts e neededad what ae strong chaacteristics of each member. Maystudents join the raceca tea, since some of niversities,ABET progr, maintain regua cicum wi credits.

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CEITsC ss Engie Pe ke E ge T

Fig. . Schematic of team conguration

Aso, team members shoud have at east persons toshe speciaized task of each p. Fig . reveas a generatea conguration. According to tea members, design andmaufacturing pas usuay divide io 8 groups: chassis,suspension, engine, powertrain, brake, eectric, maagement,task force tea. Tea eader group is tea captain whichmainy maages manufacting schedue, huma resoce,cono of conict of either design or manufacturing process,ad discussion wi chief engineer. Aso, chief engineermages engineering fabrication probems of mutidiscipin issues such as upright ad eectric ps. Chief

engineer is responsibe for periodic group meeting of eachgroup eader. During discussion of periodic meeting, a teamembers communicate directy with other groups. iscommnication processes is ve importat in maufactingperiod. Prepation requires 1 month for designing,maufacting, testing, ad picipating. Tea captainsometimes encounters situation where some members quit.Therefore, eaders shoud periodicay consut tea members tosustain a team objective and teawork.

B Concept designThe concept design meas that concepts of individua

members focus on a fabricated vehice. Fig.3. shows conceptdesign processes. The requirements of racecar e ight chassis,

high perfoace, d neutra steering in FSAE-H. Thesepeters are cosey connected with each other in tes ofhigh perfoance. Light vehice ca increase max. coeringveocity under neutra steering condition, which is high

perfoance. Aso, aong dynic events, e economy ofendance meases e consumption with In eeconomy, main technoogica issues are a vehice weight such

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Fig. 3. Concept design process

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Fig. 4. Safety reguation in roover[]

that e economy is increased. e overa weight is generayin rage of kg-5kg.

RGONOCS

Ergonomics is a critica issue in terms of drivingconvertibe. FSAE-H racecar is one seat, which driver

considers easy access to the switch as we as identiestachometer ad diagnosis information om dash pe. Tocon these activities in rea iving environments,ergonomic design is directy required in rst step of design.First of a, before chassis design, based on body informationof drivers such as arm, eg ength ad so on, the vehice designsuch as mainy dash pane, seat shape and steering wheeposition shoud be considered. Important reguations ae asfoows:

e iver's head ad hands shoud not contactthe ground in roover accident.(g.4)e driver's eg shoud not be escaped inaccident outside ont buk head.

A drivers in competition must pass emergencyescape test: within 3 second escape om vehice.Additionay, interior design supports iver attitude in saomand endurance race. If it is not satised, drivers wiconsistenty have troube.

ig 5 Chassis assemblied with engine

.SSIS

The FSAE-H ca's strcte must have two ro hoops withbracing supporter, a ont buk head, Impact attenuator, adside impact ae members.

Main hoop: a ro ocated aongside or just behindthe driver's torso

Front hoop: a ro bar ocated above e driver's egs

Front bukhead: a pana strcture that dees theford pae of the major sucture of a ame andnctions to provide protection for the iver's feet

Impact attenuator: a deformabe, energy absorbingdevice ocated forwad of ont bukhead

Chassis is a main structure hich cosey assemby suspensionad power train. Aso, this supports robusty may forces ofthe road rough suspension a in coer driving. In iscondition, e vehice which is pressured by different oads offour whees can be bent. Each tire therefore trasportsdifferent traction on the road. The design issues of chassis is tomaximize the strcture stifess der nbaaced forces omsuspension a ad driver oad, d eiminate brackets for

xing accessories. I oer words, chassis designer shoudconsider high stifess of strcture d weight. To reduce totaweight, we changed mid stee pa titaium and Auminum775. For expe, this is upright. Upright is a supporter ofwhee. When A775 is appied, the weights of four uprightsae reduced om 1 kg to 8 kg with se eve stifess. Wecan transfer the materia of whee spinde which is made of 4Cstee with heat treatment. Aso, it is changed to heat treatment

A775. Finay, we shoud minimize weding ine ength forweding each part of chassis. It meas that each team utiizehigh quaity weding technique such as IG weder, andspeciaized tea member for good weding quaity shoud betrained.

E USENSION

Suspension is strongy reated with steering chaacteristics:understeering ad oversteering. Suspension parts consist ofupper arm, ower , push-road(or pu-rod), d shockabsorber. Suspension of racing c divides into two pes;parae ad Short Long (SLA). Paae suspensionusuay is not appied in a rea ca due to extreme chageabecamber in coering. To get coering stabiity, many teamshave historicay utiized SLA suspension which the ength ofupper is shorter tha one of ower a. Therefore,according to maximum coering veocity, suspensiondesigners consider the ratio of upper and ower . Aso,

they think about kingpin incine for steering force of iver. Ifkingpin incine is high(>7), the driver wi fee tough andvibration om outside forces. On the contra, if it is ow5), the driver wi be required to tune steering whee formore force. erefore, they shoud d optima vaue betweensteering ratio and kingpin incine. Toe-iout and Caberange e aso need to be considered by designers. Firsty,generay we think that Toe-inout is ony appied to ontwhee. The camber ange shoud be changed in dynamicevents. For expe, in acceeration event, e suspension


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Fig. 6. Upright design: Rear(Le) d Front(Right)

eader must tune positive caber in ont whee ad zerocamber in rear whee. This is because ont whee of positivecamber has a roe of minimizing iction of the road, d rewhee of zero caber maximize driving traction of engine.But the camber of autocross and endurance is positive age inont d rear whees. Finay, the choice of shock absorber isaso importat. In the mid-199, the FSAE team had utiized ashock absorber for sma racing ca. However, with ightingvehice weight, the shock absorber of bicyce is a mainstream.These shock absorbers ae ve ight compaed to previousshock absorber. Among may advatages of bicyce shockabsorber, each tea ca purchase vious spring rate pats.

F HY POWERTR STRUCTURE

Hybrid Eectric Vehices have been deveoped within severacongurations. Eyeing the histo of the deveopment ofVs, the congurations can be divided into fo categoriesaccording to their operating mechaism such as a series hybrid,a parae hybrid, a power spit hybrid, ad a muti-modehybrid. Each conguration wi be introduced with simpeschematics, ad the characteristic of each conguration wi bediscussed in is chapter.

1 Series hybrid system

A series hybrid system, which has an engine used ony whenchging a battery, has one or more number of motors thatproduce traction force or recuperate braing energy [].

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Fig. 7. Physica conguration of a genera hybrid power ain.

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Fig. 8 A schematic of a genera series hybrid eectric vehice

The conguration of the series hybrid system is unique inthat the engine does not directy generate a traction forcewhie e eectric motor produces a propusion force neededto drive the vehice. Since the engine speed is independent ofthe vehice, the engine ca operate at optima operating ine,which enhces the energy eciency of the engine whiewhoe mechica energy shoud be converted to eectricenergy. In genera, efciencies of eectric power convertersike DCDC converter or motor inverter ae reativey high,but e oss when converting the energy is not a necessa

thing if the engine produces the traction force. The modeingof e series hybrid system is very simpe because thetrasmitted power is not compicated.

2 Paae hybrid system

A trasmission in parae hybrid systems transmitsmechaica power both om an engine ad an eectric motorto a vehice. Paae' means that both power resources casimuteousy generate mechaica torque. e paraehybrid system coud ive in pe eectric mode or pure enginemode which might be considered as a eectric car or just aconventiona intea combustion engine vehice. Aso, thesystem can be operated in optima point by combining thetorque of the engine d e torque of the eectric motor. iscongation is supposed to be easy to be deveoped based onexisting vehice, but, instead of it, the potentia of theimprovement might not be signicant.

3 Power spit hybrid system

We canot describe the power spit hybrid system withoutToyota Hybrid System (THS) because the concept, powerspit,' is reay started by the Japaese compay, Toyota.Patent for the power spit device using a paneta gea set isve od, which was appied in eary , but the companyenabed a ot of other techniques whie reaizing the device.

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V

Fig. 9. A schematic of a parae hybrid eectric system


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Batery

Fuel ank

Power spit device

Fig. 1. exampe of a power spit hybrid system which hasone engine and two motor/generators

The strength of the system is that the power train operates asa continuous variabe trasmission whie hybridizing the

power stream. f a superviso controer for the system has abriiat strategy, the system has a possibiity to enhace theovera efciency. Unfortnatey, the power spit system has aweakness that the power train eciency is ow at high speedbecause of indispensibe power recircuation. Nevertheess,the success of the hybrid eectric vehice, Prius,' for astdecade proves that the system is reay one of the mostadvanced systems. In static mode of the power spit system,

the motor torque d speed can be cacuated om the outputcondition d the engine torque ad speed, for which we caconsider equivaent ever diagra.

4) muti-mode hybrid system

The denition of the muti-mode hybrid systems ca beambiguous. Power spit hybrid systems which haveconvertibe mode coud be invoved in is catego, mutimode hybrid system. There ae severa types of muti-modehybrid conguration. Advaced Hybrid System (AHS)introduced by GM and Eectric-Initey VaiabeTrasmission (E-IVT) by Renaut are representative

congurations for the to-mode hybrid system. The mutimode hybrid coud overcome the rawback of the powerrecircuation when driving in singe mode, but the oss forcutch operations brings reduction of overa efciency.

G. BEThe bre design of FSAE-H has been known in twoapproaches: + design ad + one. First type is appied tofour brae caipers ad rotors in ont ad rear whee.Athough this is idea brae design, many teams woud ike todesign +1 type. Main advtage is weight oss in brae ps.Because average FSAE-H brae caiper ad rotor is around kg weight, if one bre part is eiminated, vehice weight is

reduced. However, designer woud not worry about breperfoace in +1 type. One of FSAE-H brae caiper isWiwood pas, and is is optimized products in FSAE-H( Battery )

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wr c

Fig. 11. A schematic of muti-mode hybrid system

competition. Aso, many teas have sted to design a braerotor for design exibiity such as simpe and ight uprightassemby. Therefore, bre design eaders shoud consider arotor materia and maufactring process. For exampe, abrae rotor requires high sength d therma stabiity fordurabiity. The maufactring method is ve imited due toprevious chaacteristics of a rotor. Even if these processes aenished, post processes wi be added such as materia coatingand heat treaent. Many rotors ae actured and bent in amaufacturing step.

HBODY

The body is a key roe so as to protect river's body andreduce drag force of vehice. In spite of these strongadvtages, if it is a heavy, a seek body is useess. Generay,according to maufacturing methods, the weight of body isaod 5-1kg. Some teams minimize body parts to reducetota weight due to these reasons. Nevereess, most teashave tried to appy a new fabrication method which usescabon composite as we as vacuum process. mong manymethods, vacuum processes are we-known in FSAE-H. Aerresin is injected into an origina mod, superuous resin iseiminated via vacuum outside compressor. Aso, side designis required to aayze Computationa Fuid Dynamics (CFD)for identiing cooing abiity. Because the radiator is ocatedin side chassis, side duct directy inuences on air ow inbody. Sometimes, in endrace race, some team is not adoptedto improve a side duct due to mediocre design. Recenty,many teams utiize cabon mono-ayer composite formanufacturing body.

I ISCELLANEOUS

Teas' design niquey own brae ap and adjustabe peda.

For exape, many teas make team abbreviation LED amp.This is OU (Oaad university)ad UWA (University ofWeste Austraia). Aso, reguation states that pedaadjustment pas shoud be utiized to contro the position ofpeda assemby. Because the engths of eg of drivers aedifferent, this part shoud be adjustabe. May teams designthe creative peda assemby.

J EEL & n

The whees of the ca must be 8 inches or more in diameter.May teams chooses generay KEIZER whee om US,which it is ve ight whee around .5kg. Aso, tire is criticaparaeters in competition. According to weather conditions,

each team can choose tires with various compounds. Hoosierand Good year have produced speciaized tires for ony FSAEH.

PROMOTIONAL CTIVITY

Each team requires aont of nd om thousad doas tomiion dos. However, base nd supported by university isnot sufcient to mufactre their car. Many teas hadcia probems. That is why each tea must contact mycompies to sove ancia troubes d nd new products.To contact a compy, it is required to identi their histo.The company wi nd promotiona prediction of its product,


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A

Fig. 1. Fina vehice modeing

before ofcia sponsor offer. Management team membersshoud meet the compy's requirements. erefore, theyprepare visua information to persuade a compay. Firsty,

management team contacts ociay the company to describea objective. This process offers as much as eir information,and then e company respond ofcia opinion. If a response isnegative, magement te shoud ayze a resut for a nextsponsor oer. O e con, if a respond is ve positive,maagement team sustains a good reationship

III. UFACTURING ROCESSES

Mufacting processes which e a main brier forpicipation is tighty controed. meas that the deadine ofmanufacting parts shoud be met, d team nding is wemaaged. Recommended maufacting process is the foows:

Chassis d suspension: The vehice's suctre ismufactred as soon as possibe. Wiout theseps, powertrain, steering, ad hybrid pts aemufactred.

@ Powerain d hybrid system: These pts aesongy required to contro on the dash pae. Tonish cono pe, te shoud code controsowae.

Misceaeous ps: Bre, eectrica pts andauxiia parts is ished.

Body: The fabrication processes of body proceedsepatey with main chassis maufacturing. is isna step which a parts assemby

I. ONCLUSION

The designing procedes of FASE-H are ve uniquecomped to commercia vehice due to a prototype c as weas a race c. As main issues to be considered to design a c,

The itegration between the powerain ad the powersource is very importt due to an optima operation of hybridpower maagement. Aso, these coegiate design activities

shoud be designed to improve the individua perfoace ofteam members via appropriate team congurations. Finay, evehice tests to achieve high perfoce are a a step inprior to going a competition.

CKNOWLEDGNT

The reated activi was anciay supported by BrainKorea 1 d S-IA.

EFERENCES

[1] 2010 Formula SAE rules ad importt documets, www Saeorg

[2] Nwook Kim, hD disseratio, Seoul Natioal Uiversity(2009)

designing and manufacturing of formula hybrid ieee

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