Design and Fabrication Of

Design And Fabrication Of Off Road Racing Vehicle ehicle

1. INTRODUCTION In India the first automobile ran in early 19 th century, from that time till today there has been is vast development in the different automobile sectors A vehicle is categori!ed as"small cars, #edium car, $state cars, sports cars etc %here is very less development in the racing cars category, especially for off road race vehicles in India And our aim is to design and develop such a vehicle &hich is especially for the off road races &hich are held in many countries other than India 'asically &e tried to design and develop such a vehicle &hich can meet off road race conditions Although automobiles are intended to move over a specially prepared surface (high&ay), they can move on a natural earth surface &ithout a constructed road road or &ith &ith a litt little le ine* ine*pe pens nsiv ivee prep prepar arati ation on %his %his capac capacity ity of autom automob obile ile is characteri!ed by a special property" off +the" road mobility A$ A$ (O-I$ (O-I$%. %. OF A/%O A/%O#O% #O%IV$ IV$ $0I0$ $0I0$$RI $RI0) 0) arrange arrange 2#I0I 2#I0I 'A3A4 races , every year in outh Africa, /5, / and no& they are planning to arrange these 6ind of races in India %his race is open for &orld&ide technical educ educat atio ion n univ univers ersit itie ies s From From last last five five year year,, from from Indi Indiaa only only Delh Delhii -oll -olleg egee of $ngineering is participating in this event 7e have tried to design and develop the vehicle &hich fulfills the ma*imum re8uirements of this race and &e hope to ma6e further changes as per racing needs %he design of the chassis &as first done &e have designed chassis in such a &ay that it can sustain any :er6 or impact and fulfill the entire re8uirement re8uirement for &hich the vehicle has been designed 7e have made t&o frames and then :oined them firmly fir mly,, to give more strength to the chassis %he engine &e have ta6en is of 'ullet ;<=cc, >etrol, 1?@ 'B> %his engine fulfills all po&er re8uirement of the vehicle %his engine is of ne& model (standard) 'ullet 7e have selected the clutch and gear bo* of the same standard 'ullet For this purpose &e bought &hole &hole assembly of engine, clutch and gear bo*

1 RI%, Rararamnagar

Design And Fabrication Of Off Road Racing Vehicle ehicle %he basic 8uestion then &e had been about the differential 7e selected the differential of the Auto ric6sha& (old model, front engine), &hich &as suitable for our po&er transmission to the rear a*les %he po&er transmission in bet&een the gear bo* and differential is through a chain and sproc6et arrangement %his differential has for&ard and reverse gear options o &e got four for&ard gears and four reverse gears option option &ith &ith same same differ different ential ial A separate separate lever lever is provid provided ed on the differ different ential ial to change the reverse or for&ard motion Independent suspension is used in all four &heels &ith coil spring and damper 7e have selected the front suspension of #aruti @@ for all four &heels as per our design 7e have altered the coil springs for its soft &or6ing 7e have increased the free length of the front side coil spring C inches and rear 1 inches on the basis of itEs free length %he &heel hub is of the #aruti @@ for all four &heels, because &e have four &heel independent suspensions %he stabili!ing bar used in the vehicle is also of the #aruti @@, but &e have modified it as per our &heel trac6 for front and rear side %his vehicle is rear engine rear &heel drive %he a*les used are of #aruti en (ne& model v*i) 7e had changed the lengths of a*les as per our dimensions and for smooth smooth drive drive 7e matched the Auto Auto Ric6sha&Es Ric6sha&Es a*le &ith #aruti enEs a*le, to get the drive from Differential to the &heels %he ne*t basic 8uestion &e had, the control of the vehicle %o control the vehicle safely and 8uic6ly &e decided to fit the four &heel disc bra6e facility %hen &e designed the bra6ing system for the vehicle vehicle As per our design &e chose the disc bra6e assembly (front side) of #aruti oo model for all four &heels 7e have also selected the same bra6ing fluid pipeline used in the #aruti @@, but &e have to shape it as per our re8uirements

C RI%, Rararamnagar

Design And Fabrication Of Off Road Racing Vehicle ehicle

2. ENGINE SELECTION REQUIREMENT:-

7hen &e decided to design and develop the off road vehicle for 2#I0I 'A3A RA-$4, then firstly &e studied the basic engine re8uirements for this race li6e cc, tor8ue tor8ue limitations limitations %hen by considering considering the total &eight of the vehicle including the driverEs &eight &e calculated the total po&er re8uired to propel the vehicle One more important point &e considered &as traction re8uired for off roads %hen &e finally calculated the total po&er re8uired %he total po&er re8uired &as about 1?9@ 'B> SURVEY:-

7e made survey of the mar6et for engines available in that range 7e found t&o bi6es falling under this category namely .amaha RD ;@ (t&o stro6e) and 'ullet ;@ (four stro6e) 'ut &e selected the engine of the 'ullet ;@ cc (actually;<=cc), petrol 'ecause .amaha amaha RD ;@ engine no& a days is not easily eas ily available in mar6et and the parts are also not available easily 'ut in case of the 'ullet the engine and spare parts are easily and cheaply available %or8ue of this engine &as also up to our re8uirements #aintenance of 'ullet engine is also less and cheap as compared to the RD 7hile calculating the running gear parameters, the magnitude of the po&er loss coefficient is determined and soil condition is assumed %he e*perience of using four"&heel four"&heel drive automobiles automobiles sho&s that, &hen used off"the"road off"the"road &ith hard surface, their permissible speed is limited by the suspension capabilities %he basis for engine selection is the po&er re8uired to 6eep the vehicle moving on the most probable road and and mud mud cond condit itio ion n as &ell &ell as the the resul results ts of econ econom omic ic analy analysis sis and and feasi feasibi bili lity ty evaluation An increase in the specific po&er leads to an improvement in the off"road mobility of the automobile %he basic thing about the 'ullet engine &as that it &as in our budget And this engine is also permissible for 2#I0I 'A3A4 in all the &ay li6e &eight, si!e etc 7e bought second hand engine of 'ullet &ith clutch and gear bo* assembly 7e have

; RI%, Rararamnagar

Design And Fabrication Of Off Road Racing Vehicle ehicle changed some of the engine components &hich &ere &orn out li6e piston rings, valves, head cap of the inlet valve and gas6ets, bearing cap 7e did oil change of the engine, cleaning of the carburetor, cleaning of the air filter -ontact 'rea6er (-' >oint) and condenser also needed some ad:ustments and repair FUNCTIONAL DESIGN :

Driver &eight G @ 6g -hassis and engine &tG C?@ 6g (assume ) #a*imum mass G ;@ 6g Haden mass G5s  load 5sG tatic load factor Bere, 5s for utility vehicle isG ;@ Haden mass G 6s  ;@ G ;;@ G 1@@6g Dynamic loadG 5d  laden mass 5d G dynamic load factor G 1 to C@ Assume 5d G 1 Dynamic loadG 11@@ G 19@ 6g

< RI%, Rararamnagar

Design And Fabrication Of Off Road Racing Vehicle ehicle POWER CALCULATION:

%ractive effort G 5rmg J 5aAV C 5rG@@< (For tractor in medium hard soil) 5aG1; (For tractor trailer) AG Frontal area G C m C VG<@ 5mKhrG1111 mKs %ractive effort G (@@<19@91) J (1;C1111 (1;C1111C) G 11 According to this calculated po&er &e did a survey of various t&o &heeler engine, &e selected bullet ;@cc engine &hich gives nearly the same po&er &hich &e have obtained %his &as the main reason to select the bullet ;@cc engine for our vehicle &hich has the po&er 1 'B> M =C= R>#

 RI%, Rararamnagar

Design And Fabrication Of Off Road Racing Vehicle

3. CHASSIS -hassis of the automobile is the main supporting member on &hich the follo&ing components are mounted 1 $ngine C earbo*, clutch ; uspension system < teering system  Fuel tan6 N supply system LOAD ACTION ON CHASSIS:-

a) 7eight of the component and driver causing a sagging effect due to bending action b) Bori!ontal forces provided by road irregularities act on the end of the side members deflecting the rectangular frame to a parallelogram c) /p&ard t&isting forces caused by road shoc6s to provide a torsional effect In order to provide a good resistance to bending and torsional effect the frame section should be made of proper form %here are three common types of frame sections, channel, tubular and bo* or s8uare sections &hich are used for motor vehicles -hannel section provides good resistance to bending but is poor in torsion &hile tubular section provides is good resistance to torsion but poor resistance to bending %he bo* section is comparatively resistant to bending and torsion Due to above properties &e used three sections 1 st &e made a tubular frame, but it &as not sufficient to sustain various loads o &e used -"section for rest and bo* section for engine mounting to give a good load sustaining characteristic to frame

= RI%, Rararamnagar

Design And Fabrication Of Off Road Racing Vehicle MATERIAL SELECTION: -

Ho& -arbon teels are soft, ductile, malleable, tough, machinable, &ieldable and hardenable by heat treatment %hey are good for cold &or6ing purpose &hich as rolling into thin sheets re8uired for galvani!ing, tinning or press &or6 %hey are 7eld for fabrication &or6 by &elding, pressing or machining ho&ever, they cannot be hardened by heat treatment %hey are used for &ires, nails, rivets, scre&s, panels, &elding rods, ship plates, boiler plates and tubes, fan blades, gears, valves, camshafts, cran6 shafts, connecting rods, rail&ay a*les, fish plates, cross"heads, tubes for bicycles and automobiles teels &ith @1 " @;@ L carbon are &idely used as structural steels and finds applications in building bars, grills, beams, angles, channels, etc #ild steel is &ell 6no&n %he composition N properties of mild steel are as belo&

-hemical -omposition

#echanical >roperties

-arbon P @C; L

. G C=@ 6g Imm2 (minimum)

ulpher P @@L

/% G
>hosphorus P @@L

$longation G C;@ L (minimum)

'ecause of good &elding properties N strength &e selected #for the frame fabrication

BENDING ANALYSIS OF CHASSIS:-

%he various loads li6e &eight of engine and other components, loads due to bumps and shoc6s are acting on chassis frame %hus there may be chances of bending of the frame, so &e ta6e factor of safety ; As the frame is made up of # the yield strength is C<@ 0Kmm C %here fore permissible stress G C<@K; G @ 0Kmm C

? RI%, Rararamnagar

Design And Fabrication Of Off Road Racing Vehicle As the ma*imum loads are acting on the rear part of chassis, let us analysis only the rear part of chassis %a6ing engine &eightG 9@ 6g And #a* Driver &eight Q 1@@ 6g First &e calculate the &eight distribution of driver on both the ends of supporting beam by considering it individually  @6g

@6g C=cm

<6g

<6g @cm

CCcm CCcm

Fig no ;1 >oint load acting of various section of chassis As the driver seat is supported by C beams a*is symmetrically the &eight of 1@@ 6g gets distributed as @ on each beam, and also as it is uniformly distributed load it is acting as point load at each point CC@ mm from the front support ie from  Het us analysis it as a beam

 RI%, Rararamnagar


@6gKCCcm/DH

Ccm

11cm @6g

.

CCcm



Fig no ;C" load acting on H"angle of driver seat J. G @@ 0 N %a6ing moment M *, @@ CC@G. =1@ y G1@; 0 G;19? 0 o that the load acting on the rear s8uare section



1@;0

<@0

1@;0

<@0 .1

1

;cm

Fig no ;; Analysis of engine section of chassis for bending In fig 1 N.1 are support given to the &heels %herefore ta6ing moment about 1, %he ma*imum 'ending &ill be '#G1@;CC@G<@;@J1@;=C@ G ;CC<C 0mm %he cross section of the rear frame is hollo&"s8uare therefore the #I of that section is IG ('D;K1C)"(('"b) d;K1C) G (@@;K1C)"((@";@);@;K1C) G C@;;;" <@@@ G
1@ RI%, Rararamnagar

Design And Fabrication Of Off Road Racing Vehicle f G (;CC<CK
Fig no ;< Front Vie& of -hassis frame in pro"e

Fig no ; ;"D #odel of Frame in >ro"$ngineer



Fig no ;=ide Vie& Of -hassis frame

1C RI%, Rararamnagar


Fig no ;?%op Vie& Of -hassis frame

Fig no ; Front Vie& of chassis frame

1; RI%, Rararamnagar


4. TRANSMISSION FUNCTIONS OF TRANSMISSION:-

1 %he tor8ue or %ractive effort produced by the engine varies &ith speed only &ithin narro& limits 'ut the practical consideration for the running of automobile under different condition demands a large variation of tor8ue available at &heels %he main purpose of transmission is to provide a means to vary the tor8ue ratio bet&een the engine and the road &heels as re8uired C %he transmission also provides a neutral position so that the engine and the road &heels are disconnected even &ith clutch in engaged position ; A means to bac6 the car by reversing the direction of rotation of the drive is also provided by transmission %ransmission includes" 1 -lutch C earbo* ; Drive to a*le < Differential As &e used 'ullet ;@ cc engine, &e need the transmission system &hich transmit the engine tor8ue &ith 9L efficiency &ith variable tor8ue ratios 7e selected the clutch N gear bo* of the same bi6e according to our design calculations %he design criteria of different components comes under transmission are e*plained as follo&s

1< RI%, Rararamnagar


1. CLUTCH:REQUIREMENTS OF CLUTCH:-

1 %he clutch should be able to transmit ma*imum tor8ue produced by the engine under all condition C %he clutch should positively ta6e the drive gradually &ithout the occurrence of sudden :er6 ; %he clutch should be able to eliminate the noise and vibration produced &hile transmitting po&er < i!e of clutch should be as small as possible so that it can occupy minimum space 

For higher tor8ue transmission the operation of disengagement should not be tiresome to driver %he main function of clutch is to transmit a tor8ue by 1C"1@L of the

ma*engine tor8ue For that purpose &e re8uire a clutch unit &hich transmits the tor8ue of C?< 0m M C? rpm of 'ullet ;@Also &ith in a si!e range of engine N the gear bo* &ith good heat dissipation properties All our re8uirements are fulfilled by multiplate clutch unit generally used in 'ullet ;@ o that &e used the same for our vehicle &ith an engagement mechanism provided in left foot 7e used the same cable arrangement &ith a ne& pedal operating mechanism &hich is very easy to operate During selection of clutch &e had considered a multiplate clutch &ith ; friction plates N < pressure plates At starting &e used trial N error method for diameter of plates to obtain specific tor8ue range Finally at D1G1C@mm N DCG?@mm &e get the tor8ue of
1 RI%, Rararamnagar


SELECTION CRITERIA FOR MULTIPLATE CLUTCH:-

Assuming, n1JnC G ?

total no of plates

nG=

active pairs of friction surface

p G @1

intensity of pressure

SG @;

coefficient of friction

0GC?

engine rpm at ma* %or8ue

D1G1C@mm

outer diameter of clutch plate

DCG?@mm

inner diameter of clutch plate

%herefore r1G=@mm,

rCG;mm

Intensity of pressure #a* at inner radius rC N is given as, - G >ma* rC - G @1; - G ; 0Kmm 7e 6no& a*ial force re8uired to engage the clutch is, 1= RI%, Rararamnagar

Design And Fabrication Of Off Road Racing Vehicle 7 G CT- (r1 " rC) G CT;C G <9?0 %he mean radius is denoted as UrE N given by, #ean radius G r G (r1J rC)KC r G (=@J;)KC r G <mm 7e 6no& the formula to calculate tor8ue is, %or8ue G n&Sr G =  <9?  @; 
%herefore the >o&er transmitted is, >GCT0%K=@

GCTC?G1<91 67

%hus the po&er transmitted by clutch is 1<91 67, &hich is close to the po&er transmitted by clutch of bullet ;@cc

2. GEAR BOX:

1? RI%, Rararamnagar

Design And Fabrication Of Off Road Racing Vehicle %he main purpose of using gear bo* is to obtain different gear ratios to vary the tor8ue according to road conditions N to get neutral position 7e obtained the gear ratios as per our design calculation, &hich are as follo&s,

CALCULATION OF GEAR RATIOS:-

>o&er (>) G 1;C6& $ngine speed (0) G C? peed of vehicle (v) G<@ 6mKhrG 1111 mKs #ass of the vehicle (m) G;@ 6g Diameter of &heel (d&) G@? m  G 1 W Het, nG7heel speed 7e have VGXdnK=@ n G V=@K (Xd) n G 1111=@K (;1<@?) n G ;@;1C Q ;@ rpm Final drive reduction G0KnG C?K;@ G 9
1 RI%, Rararamnagar

Design And Fabrication Of Off Road Racing Vehicle G (@@<1@@91) J (1;C1111 C) J (1@@91tan 1) %ractive effort G ;?;1 %or8ue at engine (%e) G (>=@) K (CX0) G (1CC=@)K (C;1<C?) %e G <<? 0m  (lo&er) G (%r r&)K (%eYt) Assume transmission efficiency (Yt) as 9L  (lo&er) G (;?;1 @;) K (<<?@9) G C9; ear Ratio G  lo&er KReduction in final drive G C9; K 9
Design And Fabrication Of Off Road Racing Vehicle ;G<1<= ;G1<= CK;G1<= CG;1<= CGC1< 1KCG1<= 1GC1<= 1G;1; ear ratios are 1G;1; CGC1< ;G1<= 
ear ratios 1st Cnd ;rd
'ullet C9? 19< 1;= 1

calculation ;1; C1< 1<= 1

C@ RI%, Rararamnagar

Design And Fabrication Of Off Road Racing Vehicle %hese values &ere close to our calculation, so &e decided to use gear bo* or bullet ;@cc It &as easily available and easy to fit 7e didnEt have to do any modification in it 7e used chain drive from gear bo* to differential by &elding bullet chain sproc6et to input shaft of differential for obtaining 11 drive transmission ratio

3. DIFFERENTIAL:-

In a car travel in a straight line, the t&o rear &heels turn on the road &ith same speed %here is no relative motion bet&een the t&o rear &heels 'ut &hen the car ta6es a turn, the outer &heel travels on a longer radius than the inner &heel %here is a relative motion bet&een the t&o rear &heels If the t&o rear &heels are rigidly fi*ed to a rear a*le, the inner &heel &ill slip &hich &ill cause rapid tyre &ear, steering difficulty and poor road holding %hus in order to avoid s6idding and slippage of one drive &heel in relative to other &hile cornering some device must be provided to provide relative motion %he differential serves this purpose of providing relative motion bet&een to t&o &heels 7e used the differential of 'a:a: three &heeler old models &ith engine in the front belo& the driver seat %his differential is light in &eight and has a facility of providing a reverse motion to the vehicle

C1 RI%, Rararamnagar


Fig no <1" Final drive line

Fig sho&s the line diagram of drive train In &hich po&er from engine is transmitted to gear bo* through clutch for disengaging N engaging purpose %he same sproc6et of bullet is used for po&er transmission by means of chain %he sproc6et is &elded to differential And drive is transmitted to rear &heels

CC RI%, Rararamnagar


. BRA!ING SYSTEM From safety standpoint, the bra6es are :ust about the most critical system in the racing purpose %he main functions of bra6e system are 1 In emergency they must bring the vehicle to rest in the shortest possible distance C %hey must enable control of vehicle to be retained &hen descending long hills REQUIREMENTS:

%he desired characteristics of bra6e system for A$ #ini 'a:a competition are as follo&s, 1 Reliability or fail safety C /ltimate stopping po&er ; 'alancing or proportionality < Feel or modulation

C; RI%, Rararamnagar

Design And Fabrication Of Off Road Racing Vehicle  Durability or fade resistance high = >edal pressure must be lo& ? Hife of the friction material For this &e use Bydraulic bra6e system, &hich gives better performance than #echanical bra6e system &ith less operating pedal force %here are t&o options for bra6e type, 1 Drum type C Disc type 'ut &e moved to&ards Disc bra6e system due to follo&ing advantages, 1 Disc bra6es friction surfaces are directly e*posed to the cooling air, so heat can easily dissipated C %he friction pads in case of disc bra6es are flat as compared to curved friction lining in case of drum bra6es ; %he design of disc bra6e is such that there is no loss efficiency due to e*pansion < Hess &eight  Disc bra6e have better anti fade characteristics = It is very to replace the friction pads &hen re8uired, compared to drum type &here bra6e pads are riveted Due to above advantages and to improve bra6ing performance along &ith &eight reduction, &e prefer use of disc bra6es for all four &heels In the disc bra6es there are t&o options, ventilated disc and solid disc 'ut &e selected ventilated discs due to follo&ing reasons, 1

A ventilated disc has far better capabilities per pound than solid disc

C

Ventilated disc bra6e can run a fe& hundred degree cooler

C< RI%, Rararamnagar

Design And Fabrication Of Off Road Racing Vehicle 7e need to select light &eight, hydraulic disc bra6e system &ith ventilated discs for racing purpose and for off road purpose %his re8uirement is satisfied by #aruti @@ bra6e system o &e used this BRA!ING SYSTEM DESIGN:-

I"#$% &'%':

#ass of vehicle (m) G ;@ 6g -oefficient of friction (Z) G @ 0ormal force at right rear tyre G991G9=1; 0 0ormal force at left rear tyre G 991G 9=1; 0 Radius of tyre (Rt) GC@ $ngine rpmG C? #a*imum speed of vehicle (v) G <@ 5mKhrG1111 mKs Re8uired stopping timeGC sec Re8uired stopping distanceG m 5$ G 1K mv C G C1=@ 53 Deceleration G (V"@)KC G 1111KC G  mKsecC Force re8uired to both tyres s6id

C RI%, Rararamnagar

Design And Fabrication Of Off Road Racing Vehicle G Z (0rJ0i)

G@(9=1;J9=1;) G1;C@ 0

#ean radius of rotor disc G r Range of ratio (RtKr) G C to ;@ Assume ratio C= C=G C@Kr rG 1@? mm d G C1< mm Force at rotor disc to s6id tyre (Fr) G C=  Ft G C=  1;C@ G ;999;C 0 #aterial of rotor disc G steel For ade8uate operation ma*imum >ressure allo&ed on steel (p) G C@@@ 5pa Assume factor of safety G < Assume p G 1@@6pa Area of pad G A >G FrKA AGFrK> A G ;999;CK1@@ C= RI%, Rararamnagar

Design And Fabrication Of Off Road Racing Vehicle AG ;999 Q <@ cm C %hus the above calculate values are a close to the bra6es &e used of #aruti @@ o this &as the basic reason for selecting the bra6es of #aruti @@

C? RI%, Rararamnagar


(. STEERING SYSTEM %he main function of the steering system is to convert the steering &heel angle into as clear a relationship as possible to the steering angle of the &heels N to convey feedbac6 about the vehicles state of movement bac6 to the steering &heel

STEERING SYSTEM ON INDEPENDENT WHEEL SUSPENSIONS"

As &e decided to use the independent suspension &e re8uire the steering system &hich can ad:ust &ith the independent suspension system N &heel trac6 of 1
RULES FOR RACES

Along &ith these re8uirements &e are &ith the restriction of ma* &idth 1=C@cm N >rotection of tie rod by chassis from the frontal impact as mentioned in #I0I 'A3A Rules For that &e search for the steering system &ith central steering &heel 'ut &e are unable to get the same used in any four &heeler vehicle, thatEs &hy &e go for a right hand side driven #aruti @@ 'ecause the &heel trac6 is nearly same N it can be ad:usted at central by ad:usting the length of tie rods During this &e cut the right tie rod to its half length N left tie rod is e*tended as per re8uirement by &elding In the case of rac6 N pinion teering ystem on independent &heel suspensions, it is most economical to fi* the inner tie rod :oints to the steering rac6 And in a left"hand drive passenger car or light van, the steering rac6 is carried on the right by a plastic bearing shell and on the right by guide, &hich presses the steering rac6 against the pinion gear On a right"hand drive vehicle this arrangement is reversed Fig sho&s the rac6 and pinion type of steering gear (end ta6e off type) along &ith its lin6age %he rotary motion of the steering &heel is transmitted to the pinion of the steering gear through universal :oints (not sho&n) %he pinion is in mesh &ith a rac6 %he circular motion of the pinion is transferred into the linear rac6 movement C RI%, Rararamnagar

Design And Fabrication Of Off Road Racing Vehicle %his is further relayed through the ball :oints and tie rods to the stub a*les for the &heels to be steered It has a large boot that covers the centre part of the rac6 and pinion housing A slot in the housing permits the inner tie rod ends to move &ith the rac6 Figure first sho&s the Actual ad:usted steering system &hich is modified in tie rod length It is not e*actly at centre it is shifted to&ards right because &e used only one universal :oint %he second fig sho&s the &or6ing of the system

Fig no =1 Actual ad:usted steering system

Fig no =C rac6 and pinion steering

C9 RI%, Rararamnagar

Design And Fabrication Of Off Road Racing Vehicle STEERING GEOMETRY:-

F)* "+ (.3: ,%)"* *+/%0

;@ RI%, Rararamnagar

Design And Fabrication Of Off Road Racing Vehicle CAMBER:-

-amber is the tilting of the front &heels from the vertical 7hen the tilt is out&ard, so the &heels are farther apart at the top than at the bottom, the camber is positive >ositive camber is sho&n in Fig 7hen the tilt is in&ard, so the &heels are closer together at the top than at the bottom, the camber is negative %he &heels are given a slight out&ard tilt to start &ith so that &hen vehicle is loaded and rolling along on the road, the load &ill :ust about bring the &heels to a vertical position Any amount of camber"positive or negative "tends to cause uneven or more rapid tire &ear, since the tilt puts more of the load on one side of the tread than on the other %he values of camber after ad:ustment &ere, For left

J@W;?[

For right

"@W;C[

;1 RI%, Rararamnagar

Design And Fabrication Of Off Road Racing Vehicle !INGPIN INCLINATION:-

5ingpin inclination (or 5>I) is the in&ard tilt of the 6ingpin from the vertical (Fig) 5ingpin inclination is desirable for several reasons First, it helps provide steering stability by tending to return the &heel to the straight ahead position after any turn second, it reduces steering effort, particularly &hen the car is stationary and third, it reduces tire &ear

TOE-IN OR TOE-OUT:-

%oe"in is the turning in of the front &heels they attempt to roll in&ard instead of straight ahead On a car &ith toe"in, the distance bet&een the front &heels is less at the front than at the rear %he actual amount of toe"in is normally only a fraction of an inch %he purpose of toe"in is to ensure parallel rolling of the front &heels, to stabili!e steering, and to prevent side slipping and e*cessive &ear of tires In other &ords, even though the &heels an\ set to toe in slightly &hen the car is standing still, they tend to roll parallel on the road &hen the car is moving for&ard %he values of toe &ere, For left J@= mm For right "1?? mm

;C RI%, Rararamnagar


. TYRES ROAD WHEELS AND BEARINGS TYRE REQUIREMENTS"

>neumatic tyres for motor vehicles must basically satisfy the follo&ing re8uirements •

upport the &eight of the vehicle and distribute it over the road surface

•

%o offer the minimum rolling resistance to the motion of the vehicle and thus

reduce po&er absorption •

%o contribute to the suspension cushioning of impact forces created by road

surface irregularities •

%o permit the generation of traction, bra6ing and steering forces on dry or &et

road surfaces •

%o confer safe operation up to the ma*imum speed of vehicle

•

%o provide 8uiet straight"ahead running and freedom from s8ueal on cornering

and bra6ing •

%o reali!e an acceptable tread life under varied running conditions

TYRE CHARACTERSTICS"

7hen a vehicle is being driven along the road, the tyres are acted upon by a comple* and variable system of forces that arise in the vertical, longitudinal and lateral directions %he manner in &hich the tyres react to these forces defines their main characteristics, CUSHIONING ABILITY"

%he pneumatic tyre contributes to the ride comfort of the vehicle by acting as a spring in series &ith the suspension system (figure)

;; RI%, Rararamnagar


ROLLING RESISTANCE"

'asic consideration affecting the fle*ibly tyred &heel, freely rolling on a rigid"road surface, is that it must inherently posses a resistance to motion %his effect arises because the deformation of the tyre tread tends 7e used regular radial ply tyres used for cars and vans %hey are cheaply and easily available 'ut for races a special tyres are re8uired having high coefficient of friction and high &idth It is not easily available and is of high cost, thus considering cost reduction factor &e used the radial ply tyres ROAD WHEELS AND HUBS"

%he design features necessary for all &heels may be summari!ed as in the follo&ing sections LIGHTWEIGHT CONSTRUCTION"

$ach &heel adds significantly to the unsprung mass of its suspension mechanism ince it is easier for a shoc6 damper to control the bouncing movements of a small rather than a large unsprung mass, it follo&s that for good road holding the &heel should be made as light as possible STRENGTH AND RIGIDITY"

A &heel must possess sufficient strength to &ithstand all normal service loads imposed upon it It must further be rigid or stiff enough as a structure to minimi!e bending deflection under steering and cornering loads TYRE RETENTION"

%he design of the &heel rim must permit the mounting and removal of the tyre and retain it securely in position &hen inflated

;< RI%, Rararamnagar


WHEEL HUBS AND BEARINGS"

%he arrangement of hubs and bearings used in a*les is as follo&s 1 Independent front suspension (IF) &ith non"driven C Independent front suspension (IF) &ith driven &heels ; Independent rear suspension (IR) &ith driven &heels < Independent rear suspension (IR) &ith non"driven &heels 7e used 0umber 1 N ;, &hich are" 1. IFS )% "+"-&)5" 6, "

%he hub bearing arrangements for this system generally continue to follo& those of beam"a*le mounted &heels %hat is, each hub rotates about a dead spindle through the medium of an opposed pair of either angular"contact ball, or tapered roller, bearings Bo&ever, the re8uirements in respect of their load carrying capacity have tended to increase, because of the more for&ard mounting of the engine permitted by IF 2. IRS )% &)5" 6, "

For driven rear &heels independently sprung by popular semi"trailing arm system, the modern approach is to use a double"ro& angular"contact ball bearing hub unit similar to that described for IF &ith driven &heels ince the bearing arrangements in both, cases are basically the same, one manufacturer for e*ample uses a common hub bearing unit for the driven front &heels of one model and for the driven rear &heels of another For heavy"duty applications, the earlier practice of using an opposed pair of either deep"groove ball, or tapered roller, bearings may still be follo&ed 7e used cast alloy &heel of #aruti car %hey are cheaply easily available It is light in &eight and one piece casting Bave high strength and light in &eight

; RI%, Rararamnagar


7. SUSPENSION SYSTEM %he suspension of modern vehicles need to satisfy a number of re8uirements &hose aims partly conflict because of different operating conditions (loaded K unloaded , acceleration K bra6ing , level K uneven road, straight running K cornering) ufficient vertical spring travel, possibly combined &ith the hori!ontal movement of the &heel a&ay from an uneven area of road (6inematics &heel) is re8uired for reasons of ride comfort %he recession suspension should also be complaint for purpose of reducing the rolling stiffness of tyres and short"stro6e movement in longitudinal direction resulting from the road surface, but &ith affecting the development of lateral &heel forces and hence steering precision, for &hich the most rigid &heel suspension is re8uired %his re8uirement is undermined as a result of the necessary fle*ibility that results from disturbing &heel moment generated by longitudinal forces arising from driving and bra6ing operation REQUIREMENT OF SUSPENSION SYSTEM:•

Independent movement of each of the &heels on a*le

•

mall, unsprung masses of the suspension in order to 6eep &heel load fluctuating as lo& as possible

•

%he introduction of &heel forces into the body in manner favorable to the flo& of forces

•

%he necessary room and e*penditure for construction purposes, bearing in mind the necessary tolerances &ith regards to geometry and stability

•

$ase for use

•

'ehavior &ith regards to the passive safety of passengers and other road user

•

-ost

;= RI%, Rararamnagar

Design And Fabrication Of Off Road Racing Vehicle INDEPENDENT SUSPENSION SYSTEM"

%he chassis of a passenger car must be able to handle the engine po&er installed $ver improving acceleration, higher pea6 and cornering speeds, and deceleration leads to significantly increased re8uirements for safer chassis %he independent &heel suspension follo&s this trend %he independent &heel suspension has follo&ing advantages" teering effect due to lateral movement of the tyre K road contact patch, as the

•

&heel rises and falls are obviated A*le tramp, and particularly that associated &ith alternative &ind"up and

•

release leaf of springs sub:ected to bra6e tor8ue, is obviated It is possible to obtain softer suspension &ith large &heel displacements

•

&ithout raising the center of gravity •

Variation in castor angle due to &ind"up in obviated

•

A coil spring can be more easily accommodated close to a &heel that has to be steered than can be semi"elliptic spring

•

/nsprung mass is lighter and therefore the ride 8uality improves

•

%he roll center can be lo&er and the spring base &ider, so the roll resistance is higher %he effect of high roll resistance is that softer springing can be used &hich reduces the tendency to pitch •

Hittle space re8uired

•

Ho& &eight %he independent suspension system has many advantages as compared to

other suspension system &hich are stated above o &e decided to use independent suspension system for &heels %he simplest independent suspension is #c>herson strut suspension It is used in almost all the vehicles

;? RI%, Rararamnagar

Design And Fabrication Of Off Road Racing Vehicle MCPHERSON STRUT AND STRUT DAMPERS:-

Fig no 1 #c>herson strut suspension 7e used #aruti @@ #c>herson strut suspension system for both front and rear &heels as our location of engine is on rear side It is easily available and has lo& cost then any other suspension system Our vehicle had a &eight of ;@ 6g &hich &as not enough for the &or6ing of suspension, so small vibration &as transfered to the steering %o overcome this problem &e :ust increased the free length of the coil spring 0o& the suspension is free enough to absorb the vibration %his change &as made in the suspension ANTI ROLL BARS:-

An anti"roll bar is basically a torsion bar type of spring &ith angled ends, and its action is sho&n in (Figure) It is mounted transversely and in such a manner as to connect the locating lin6ages of opposite &heels, &hile remaining torsion ally free &ith respect to the vehicle structure It thus performs the function of resisting rolling, as its name &ould suggest, but not bouncing motions of the vehicle Bo&ever, the amount of roll restraint contributed by an anti"roll bar must necessarily be limited,

; RI%, Rararamnagar

Design And Fabrication Of Off Road Racing Vehicle because it also has the effect of stiffening the suspension in response to single &heel bumps and can therefore compromise ride comfort %he anti"roll bar &as once generally confined in application to the front suspension, because it had the effect of redistributing the overall lateral &eight transfer bet&een the front and rear pairs of tyres in favour of promoting under steer %he slip angle of a tyre can also be increased if the vertical load becomes greater, &hich is the effect that the addition of an anti"roll bar has on the already heavily loaded outer &heel of a pair during cornering In more recent years there has been a trend to include an anti"roll bar in the rear suspension system as &ell, partly to correct any condition of e*cessive under steer and partly to reduce roll further 7e used anti roll bars in the rear side also 7e had to increase the length of the stabili!er bar by cutting it and fi*ing another bar by &ielding %his made us easy to fit the bar at proper place

Fig no C " Action of anti"roll bar

;9 RI%, Rararamnagar


S68%)+" 8)%)' 9+ 8+)6 ,#)"*:-

Assume  G < 50Ks8mm pring inde* (DKd) G  G hear stress intensity G fs G
1. M'" &)'/% ,#)"* 8+)6

D G #ean diameter of spring D G Diameter of spring coil

7ahlEs factor 5 G ((<-"1)K(<-"<)) J (@=1K-) G 11

M')/$/ ,' ,%,,

fs G 6(&cKXdd)

d G 99C mm

#ean diameter of spring D G cd G   99C G ?9;= mm

Outer diameter of spring coil, DoG D J d G ?9;=J99C

<@ RI%, Rararamnagar

Design And Fabrication Of Off Road Racing Vehicle G 9C mm

2. N$/; +9 %$", +9 8+)6

n G number of active turns of coil Deflection of spring, ] G (&cccn)K (d) @G (1?1=?<n)K (<@@@99C)) n G 9C Q =

For s8uared and ground ends %otal number of turns

nEG nJCG =JCG 

3. F 6"*% +9 ,#)"*

G nEd J ] J@1] G (99C) J@J@1(@) G 1;?mm

4. P)%8 +9 8+)6

G free length K nE"1 G 1;?K"1 G 19=
. S#)"* ,%)99",,

G (d^<)K (D^;n) G (<@@@99C^<)K (?9<;^;=) G ;;1@

<1 RI%, Rararamnagar

Design And Fabrication Of Off Road Racing Vehicle %hus dimension according to our calculation are, Diameter of spring G 1@mm #ean diameter of coil G@ mm Outer diameter of spring coilG9@ mm 0umber of active turns of coilG = Free length of springG1;?mm >itch of coilG19=< pring stiffnessG;;1@

%his calculated value of suspension is close to the value of the #aruti suspension system o &e used #aruti #c>herson strut suspension system for all four &heels


<. TESTING AND PERFORMANCE

For any vehicle &hich is manufactured has to go through the some important tests %hese tests are generally carried to get the performance of the vehicle for particular test condition %hese tests are carried out by the manufacturer itself As per the class or type of the vehicle the different tests are decided >erformance of the vehicle is defined as the results of the different tests for particular vehicle ItEs unit may be time, angle, 6ilometer per hour (6ph) etc For the testing purpose of the vehicles manufactured in India government has established the centers li6e ARAI (Automotive Research Association of India), VRD$ (Vehicle research And Development $stablishment)%he basic function of these centers is to test the different class of vehicles &hich are manufactured in India and going to launching in fe& days In this centers the different trac6s, road conditions, different machineries re8uired for the tests are available 7ithout the permission of ARAI no vehicle can be sell in India, by any manufacturer %here are ideal conditions are maintained in these centers for testing purpose 7hile &or6ing on this pro:ect our basic aim &as to improve the performance of the vehicle For that purpose all standard recommended components &ere used After completion of the pro:ect actual tests &ere started %he different tests &ere carried out by our self only As this vehicle is made for the off road race purpose, so &e had tests only related &ith the race application %he basic tests &e had as follo&s" 1 #a*imun speed C Acceleration ; Deceleration < Fuel consumption  teering angle

<; RI%, Rararamnagar


1. MAXIMUN SPEED:-

%his is one of the main test for the vehicle to 6no& its po&er utili!ation It is the ma*imum speed the vehicle can achive irrespective of time As our vehicle doesnEt have any speedometer &e had to :ust run a t&o &heeler side by side to 6no& the ma*imum speed %he ma*imum speed of our vehicle is <@ 6mKhr 2. ACCELERATION TEST

%his test has importance for 6no&ing the accelerating capacity of the particular vehicle in particular time limit %his is nothing but obtaining the particular speed in particular time %he instrument &e re8uired is stop &atch only %hen &e too6 the readings for <@ 6mph (6ilometer per hour) %he time re8uired for obtaining this speed &as 6no&n %his time obtained &as C1 seconds %his result &as satisfactory on this level %he results &ere as follo&s peed decided G<@ 6mph %ime re8uired GC1 seconds

3. DECELERATION TEST:

%his test is generally performed for 6no&ing the bra6ing control of the vehicle for particular speed in relation &ith time One more important point is the vehicle should not s6id during bra6ing o simply the speed is generally considered the accelerating speed of the vehicle and then bra6es are applied suddenly and the stopping distance is measured till the vehicle attempts the speed of !ero From that

<< RI%, Rararamnagar

Design And Fabrication Of Off Road Racing Vehicle time &e come to 6no& the control of the vehicle during bra6ing %he readings obtained &ere as follo&s peed of vehicle G <@ 6mph 'ra6ing distance G =? seconds %his result &as also satisfactory for our vehicle

4. FUEL CONSUMPTION=

For every vehicle this point is very important 'y 6no&ing this &e can get the idea about the average or mileage of that vehicle It is nothing but the fuel consumption by the vehicle in particular distance From that &e can easily calculate the mileage of that vehicle for one litter of the fuel For this test &e too6 the vehicle on the trac6 as same as made for the race and fill the @@ml of petrol into fuel tan6 %hen side by side &e 6ept one bi6e for speedometer reading and note the reading of the speedometer %hen &e started the vehicle 7e ran the vehicle still total fuel &as over %hen the total distance traveled by the vehicle &as noted Form that &e got the mileage of the mud vehicle 7e tried to too6 the reading related to application of the vehicle %he readings are as follo&s Fuel consumption G @@ml %otal distance traveled G 1C 6m Final average G C@ 6m

. STEERING ANGLE:-

%his is not the test actually, but this is the measurement of tyre angle of both front tyres %his is very helpful for getting the turning radius of the vehicle on both < RI%, Rararamnagar

Design And Fabrication Of Off Road Racing Vehicle the side ie right side and left side %his angle is also helpful for &heel alignment of the vehicle settings If this angle is more for any side &heel then s6idding may occur uring turning and unnecessary &ear of the tyre ta6es place %here are computeri!ed testing and manual testing for this purpose 7e tested manually For that purpose proper tyre inflation is maintained %hen the vehicle is 6ept on the plane ground level %he front &heels 6ept straight and one longitudinal line is dra&n from the centre of both the tyres %hen steer the vehicle on the right side fully Again one line is dra&n from the tyre centre %he angle bet&een both these lines &as measured %his angle &as for right side of the vehicle ame procedure &as adopted for the left side &heel and angle &as measured %he reading &as as follo&s Right side angle G C_ Heft side angle G C_

<= RI%, Rararamnagar


1>. VEHICLE SPECIFICATION ENGINE:

F+$ S%+?, OHV

CUBIC CAPACITY

34(88

BORE @ STRO!E

>//  <>//

COMPRESSION RATIO

.2:1

ENGINE POWER

17 BHP  (2( RPM

OUTPUT TORQUE

2.4 ?*/  27 RPM

IGNITION

B'%%0 @ C+)6

CLUTCH

M$6%)#6'% - O)6 )//,&

TRANSMISSION

4 S#& - C+",%'"% M,

FUEL CONSUMPTION

2( !/L%

SUSPENSION

M8P,+" S%$% T0# I"&#"&"% F+ '66 9+$ 6,

CHASSIS:

M)6& ,%6 >-> L-S8%)+"

LENGTH

21(>//.

WIDTH

<7>//.

HEIGHT

114//.


11. CONCLUSION %his pro:ect &or6 is carried out by us to ta6e the participation in the 2#I0I 'A3A4 the engineering pro:ect competition arranged in outh Africa For that &e have concentrated to match their rules and regulations As the vehicle is made for the race purpose, so &e have concentrated on the po&er not on economy During the pro:ect &or6 &e come to 6no& that &hat 6ind of technical as &ell as other problems came across the &or6 In this pro:ect &or6 &e applied lot of principles of different sub:ects &e studied in the engineering From that &e got revie& over some of the sub:ects %here is lots of modification still needed to match all re8uirements 7e &ill try to modify as per the rules before race 7e also got the 6no&ledge of fabrication &or6 7e purchased lot of material form mar6et, so &e understood ho& to deal &ith people During the &or6 sometimes &e had to ta6e decisions so some of the leadership 8ualities are also improved 7e also get an opportunity to handle the different special purpose machines and precision e8uipments %his is the innovative 6ind of &or6 &e have done together 7e also learned to &or6 in group to achieve the common goal Bo& to face the problems, also find the variety of solutions and select the best one among the all solutions

< RI%, Rararamnagar


12. FUTURE SCOPE Our concept to design a high tor8ue engine vehicle, &hich completes the basic re8uirements of UA$ #I0I 'A3A -ompetition Uis 8uite successful It gives better performance >erformance testing related to fuel consumption, ma*imum speed, ma*imum acceleration, stopping distance and time gives e*pected results 'y using this vehicle &e obtain average of C 6m, ma*imum speed of <@ 6mKhr in C; seconds



'ut some dra&bac6s are there, &e can remove that dra&bac6s in future and can obtain better performance %his &ill done by modifying present systems or using some advanced techni8ues ome dra&bac6s are listed belo& 1 tarting problem C #ore chassis &eight ; $ngine noise and vibration < Hess ground clearance Due to cost factor and less span available, &e &ere unable to remove the above dra&bac6 for getting performance results 'ut in future there is scope to do this by adopting follo&ing techni8ues 1 S%'%)"* #+;6/ 7e used bullet ;@cc engine &hich had a 6ic6 starting mechanism %his is very time consuming procedure to start engine, but our cost estimation of pro:ect is not that much to purchase engine &ith self starter or electronically startor engine %his &ill again increase pro:ect budget &ith ;,@@@K to <,@@@K %he better solution or future scope is to self started or electronic s&itch started engine or 'riggs and tratton engine &hich &ill sponsored by A$, during second time participation in competition <9 RI%, Rararamnagar

Design And Fabrication Of Off Road Racing Vehicle 2. C',,), )*% &$8%)+":

In recent design &e select  H"section for chassis frame of iron metal %his frame is supported or reinforced by cylindrical frame of 1< gauge of diameter 1 inch from inside 'ut this is responsible to increase &eight of frame up to C?@ 6g As &e made tubular chassis 1st but it &as not possible to carry the load of engine and other components so &e had to use H"section &hich increased the &eight of chassis A$ #I0I 'A3A -ompetition allo&s gross vehicle &eight up to ;@ 6g, but by reducing the &eight &e can improve fuel economy 7e can reduce the &eight by selecting the material of light &eight and high strength 7e can select the round or s8uare section for this 3. E"*)" "+), '"& 5);'%)+" &$8%)+":-

7e used bullet ;@ cc engine, this produces more noise and vibration but for reduction in noise and vibration level &e have options li6e RD ;@ cc engine , 'riggs and tratton engine 7e are not using RD ;@ cc t&in engine due to unavailability in the mar6et in desired cost If mountings &ith rubber cushion are provided to bullet engine, it &ill also reduce vibrations 4. M+ *+$"& 86''"8:

Our vehicle has ground clearance of 1< cm this ground clearance is less due to use of radial tyres &ith 1C inch diameter For effective use as off road vehicle &e have more ground clearance %he main re8uirement of off road vehicle &ill satisfied by &ith help of sports tyres

@ RI%, Rararamnagar

Design And Fabrication Of Off Road Racing Vehicle Along &ith above there are many other future scope to get better performance and that are U, +9 CVT:-

-V% (continuous variable transmission) gives high rear ratios then manual transmission, improves performance, fuel economy and smoother operation -V% is available &ith 'riggs and tratton engine, &hich is sponsored by A$ during second time participation in competition

1 RI%, Rararamnagar


13. BIBLOGRAPHY

1 3Reimpell,

Btall,

37'et!ler,

2%he

automobile

chassis4,

A$

International Independent &heel suspension (?"1), teering+rac6 and pinion (C?1"C?=), spring (;<=, ;?";??)

C Van Val6enburgh, 2Race car engineering N mechanics4 %ires N &heels (?"19), uspension, steering geometry N Alignment (19";;) prings, anti"roll bars (;;";)

; Bappian N smith 2#odern vehicle design4, A$ International #aterial selection (C9"<<), -hassis design and analysis (1C" 1C)

< #30unney, 2Automotive technology4 ,A$ International #ultiplate clutch (C?9), %yres, road &heels N hubs (<;"<<)

 5ripal ingh, 2Automobile engineering vol +I4, tandard publication #ultiplate clutch (=9"?@), uspension (CC?"C;;), steering (C?9"CC)

= 50e&ton, 7teeds, %5arrett , 2%he motor vehicle4, 'utter&orth" Beinemann %ransmission (=@1, =<1"1)

? VD5odgire, 2#aterial cience N #etallurgy4, $verest publication #aterial selection (;C9)

 V''handari, 2Design of machine elements4,%ata #cra& Bill publication -lutch design (;;1), 'ra6es (;<=";<)

9

>>atil, 2#echanical ystem Design4, 3aico >ublishing Bouse C RI%, Rararamnagar

Design and Fabrication Of

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