Project by: Team Thunderbirds (SAE BAJA 2015)
Jul 18, 2015
Thunderbirds set out to design and constructan all-terrain utility vehicle. The team’s vehiclethe trendnought ,has two treads to allow it totraverse a wide variety of terrains such assnow, mud ,grass and gravel.
BRIGGS AND STRATTONBriggs & Stratton is the world's largest manufacturer of air-cooled gasoline engines primarily for outdoor power equipment. Current production averages 11 million engines per year.
Briggs & Stratton engines are commonly used on lawnmowers.
Displacement [cc] = 306
Bore [mm] = 82
Stroke [mm] = 58
Weight [kg] = 25
Oil Capacity = 1.1
Compression Ratio = 8.0 to 1
MAHINDRA ALFA
The Alfa is a three wheeler goods carrierdesigned to make the loading, transportation,and unloading of small cargos easier.
Mahindra equipped the Alfa with the largestand strongest cargo box yet at 24.5 cubicfeet, and then adapted the structure tohandle oversize loads.
Engine Type = 4-stroke, Single Cylinder, air cooled diesel engine
Displacement = 395.00 CC
Maximum Power = 5.51 KW @ 3600 rpm
Maxiumum Torque = 16.7 Nm @ 2200-2800 rpm
MaxSpeed = 53 Kmph
Transmission = Constant Mesh
Clutch = Multi Plate Wet Clutch
Gearbox = 4-speed
Mechanical The engine and power train option that was considered was a mechanical gearing system powered by an internal combustion engine. While the mechanical system can’t provide the zero-turn capabilities as simply as hydraulic or electric systems can.
Primary gear ratio=2.86
Secondary gear ratio=2.38
Final gear ratio=primary gear ratio*secondary gear ratio*individual gear ratio
Gear Individual Gear ratio Final gear ratio
1 4.62
31.45
2 2.75
18.70
3 1.67
11.40
4 1.08
7.35
Reverse 8.09
55.05
TORQUE=Maximum torque by engine*final gear ratio
Gear Torque(N)
1 587.80
2 349.50
3 213.06
4 137.37
5 1028.88
Radius of wheel=0.317m
Force on wheel=torque/radius
Gear Torque(N) Radius(m) Force(N)
1 587.80 .317 1854.25
2 349.50 .317 1102.52
3 213.07 .317 617.94
4 137.37 .317 433.34
Reverse 1028.88 .317 3245.67
RPM =Engine rpm/final gear ratio of different gear engine rpm=3800
Gear Engine rpm Final gear ratio rpm Rps=rpm/60
1 3800 31.45 120.82 2.01
2 3800 18.70 203.20 3.38
3 3800 11.40 333.33 5.55
4 3800 7.35 517.00 8.61
reverse 3800 55.05 69.02 1.15
Aerodynamic drag=0.5 *p*A*V*Cd
A=frontal area of vehicle=1.0966
Cd=coefficient of drag=0.6
Gear Aerodynamic drag
1 6.33
2 17.93
3 48.27
4 116.13
Rolling resistance =mg*Crr
m=mass of vehicle=250kg
g=accelaration due to gravity
coefficient of rolling resistance=0.15
total resistance =drag+rolling resistance
Gear Rolling resistance Aerodynamic
resistance
Total resistance
1 367.5 6.33 373.83
2 367.5 17.93 385.43
3 367.5 48.27 415.77
4 367.5 116.13 483.63
Tractive force =force on wheel-total resistance
Gear Force on wheel(N) Total resistance Tractive force(N)
1 1854.25 373.83 1480.42
2 1102.53 385.43 717.10
3 617.94 415.77 202.17
4 433.34 483.63 50.34
Acceleration=tractive force/weight of vehicle
Gear Tractive force Acceleration Time taken
1 1480.42 6.02 0.66
2 717.10 3.02 2.32
3 202.17 1.16 4.36
4 50.34 1.08 11.34
Components Cost
Frame & Body 40,000-/
Suspension 20,000-/
Wheels & Tires 50,000-/
Steering 10,000-/
Breaks 15000-/
Engine & gearbox 60000-/
Instruments & wiring 10000-/
Driver accessories 50,000-/
Logistics & travel 40,000-/
Promotion & merchandise 20,000-/
Competition fees 50,000-/
Total 3,65,000-/
Engine & gear
Total Rs3,65,000
Components Cost
B&S Engine 35,000
Transmission 19,000
Labour Cost 6,000
Total 60,000
Engine & Gearbox:Standard B&S engine, Mahindra Alpha Transmission.
It is used to get various speeds in different load conditions.
It increases fuel efficiency. Increases engine efficiency. Need less power input when operated manually. They are more practical when there is a space
limitation.
Robust transmission and longer gearbox life.
Best suited for Briggs and Stratton engine.
Compact and easily available in the market.
Data of Specification and features are easily available.
www.bajasaeindia.org/
www.irdindia.in/journal_ijmer/pdf/vol1_iss1/17
www.mahindrasmallcv.com/bolero_alfa_passenger_diesel
www.grabcad.com/library/briggs-and-stratton-10hp-engine-for-baja-sae
www.briggsandstratton.com
www.mahindrajhbsouth.co.za/mahindra-alfa-specifications/
grabcad.com/library/mahindra-alfa-champion-gearbox-1