The Propulsion System Engineering Essay

The Propulsion System locomotive engineering EssayThe propulsion schema with respect to this application discount be defined as the system which provides fomite motion. Thus, this project involves the design of a system for efficient ply generation and contagion of power from power dress to the driving wheels with minimum power point losses.All design features must comply with the shell Eco-Marathon Asia 2010 rules and regulations 1Main objectivesSelection of a suitable energy parentage to power the vehicle everywhereall system design logical argument pickax and design of comp sensationntsDetailed analysis and optimization of each sub system for supreme provoke efficiency click modeling and detailed musterVerification of selected and intentional components finished calculation and suitable simulation softwareFinal executing estimationAll design features must be approved by shell Eco-Marathon organizersParts quotation1.2 About the competitionThe principle of the Shel l Eco-Marathon is entirely to design and build the about send away efficient vehicle while producing the fewest emissions. 1, 30Teams can enter both main categoriesFuturistic prototypesThese are silky vehicles where the primary design consideration is reducing drag and maximizing power train efficiency. This category has fewer restrictions. 1Urban C formerlypt vehiclesThese are built to more than conventional 4-wheel roadworthy criteria. 1Design requirements and other rules related to the propulsion system are listed in Appendix F1.3 Competition category and energy source selectionAfter few days of research and discussion considering time, cost and expertise of team, it was decided to compete under the prototype category with an internal combustion railway locomotive running on ethanol as the power plant.CHAPTER 2.0LITERATURE REVIEW2.1 IntroductionThis literature review provides details on past endurance vehicles and the in vogue(p) organic evolutions in the area of fuel e fficiency, substitute(a) fuels and future propulsion systems.Articles and reports were found related to vehicles designed and developed mainly for Shell Eco-Marathon and SAE Supermileage competitions.2.2 The world recordThe most fuel efficient gondola in the world, PAC Car II designed and developed by ETH Zurich (Swiss Federal Institute of Technology) was powered by a Hydrogen fuel cell and it had a record of 12600 Miles per Gallon (US) during the Shell Eco-Marathon, France in 2005 3. This clearly indicated the level of competition, amount of potential for fuel efficiency and alternative fuels.2.3 grain alcohol as vehicle fuelArticles 4 on ethanol combustion and renewing of shoot a lineoline engines were found which provided detailed practical explanation.An ethanol powered car engineered by French gamy school students from Lyce La Joliverie had achieved the best fuel efficiency at the European Shell Eco-marathon 2006, winning the race at the Nogaro auto racing circuit in south west France by travelling 2885 kilometers per liter of gasoline equivalent. It also took the Climate Friendly prize for producing the least nursery gas emissions. 6Currently ethanol E85 (85% ethanol) powered vehicles are produced by leading automotive manufacturers such as Ford, Chevrolet, Chrysler, Toyota, Nissan etc 82.4 Engine and mother trainVehicle designed and built by Alerion Supermileage team from Laval University of Quebec, Canada won the grand prize of the Shell Eco-Marathon Americas 2010 recording 1057.5 kilometers per liter. This vehicle consisted of an internal combustion engine.The Dalhousie University team had employ the Honda GX35 engine for their vehicle with a direct drive transmission system for Shell Eco-Marathon Americas in 2008/2009 which travelled 332.8 km/l gasoline 5. Experimental apprizes obtained by dynamometer testing for the GX35 engine were also published. 22.5 Fuel delivery systemsMost endurance vehicles in previous competitions had mechanical fuel pumps to pressurize fuel. The Dalhousie team used a pressurized fuel system in 2008/2009 which yielded successful up pinchs. Fuel injection systems are known to be more efficient than carburetor systems since there is more affirm over the spray of fuel.2.6 inlet and exhaust systemThe internal combustion engines and fluid mechanics online lecture notes published by the Colorado State University provided prefatory explanation about expenditure/exhaust tuning. Current developments in this field are related to variable valve cadence.Fiat was the scratch line automotive manufacturer to open a variable lift system. Developed by Giovanni Torazza 1960, the system used hydraulic pressure to vary the fulcrum of the cam fol upseters (US Patent 3,641,988). The hydraulic pressure agitated accord to engine speed and intake pressure. 43After continued improvement, a system with variable valve clock, two stage valve lift on the intake valves and variable timing of the exhaust valves wa s developed by Porsche in 2009. 40In 2010, Mitsubishi developed and started mass production of the 4N13 1.8 L Diesel Overhead Cam Inline 4 cylinder engine. This is the first rider car with a diesel engine that features a variable valve timing system. 392.7 Latest trends in fuel efficiency there is much research and development in the area of hydrogen fuel cells and hybrid systems. Although the principle of the fuel cell was discovered in 1838, it has not been a popular topic until upstart years. Currently, hybrid systems and hydrogen fuel cells are considered the future of vehicle propulsion systems.CHAPTER 3.0ENGINE THE SYSTEM POWER PLANT3.1 IntroductionA small quadruple bias gasoline engine was required to be selected and modified for ethanol combustion with utmost fuel efficiency.3.2 Fuel neutral spirits E100The main idea rear selecting ethanol as the fuel for the engine is that ethanol has a high octane value (Higher auto ignition point). accordingly the engine will no t roast at higher muscle contraction ratios. 8, 4It is also a renewable fuel produced by corn, sugar cane etc and although controversial is regarded as generating less toxic emissions. 83.3 Stock engine selectionMain specification guidelines set in order to select few potential engines that can be used for the systemEngine typeAir cooled, four stroke, single cylinder petrol engineDisplacement35 to 50 cm3Power OutputMaximumMass minimumTable 1.0 Specification guidelines for selectionAdhering to the set guidelines (refer table 1.0) few potential engines were selected.Scooter engine, 139QMB, 9350R/S 35cc Robin/Subaru 4-Stroke engine used for bicycles, 10Honda GX35 mini 4 stroke used in lawn mowers, 11Gasoline engine (142F) manufactured and supplied by Shandong Huasheng Zhongtian Machinery group CO.LTD, 12Detailed specifications for these engines are given in vermiform appendix C3.3.1 Parametric makeMain parameters considered for this study were specific fuel ingestion, mass, ease of modification, availability, versatility and reliabilityThe fuel efficiency of an engine is directly related to the brake specific fuel consumption. 13During the autumn semester, the drive train was assumed to be 100% efficient and mass of car without engine was estimated as 330lbs.These values were only used for comparing engines.The miles per gallon values were estimated victimisation the roll and Grippo program for dissimilar BSFC values. 7The estimates for coefficient of drag, frontal area, tire inflation pressure, vehicle free weight were obtained from other team members in charge of each sub assembly. platform inputsCoefficient of drag0.13Frontal area (Square feet)8.04Vehicle miles per hour (MPH)18Vehicle weight in lbs330Tire inflation pressure in psi80Engine Brake Specific Fuel Consumption (gal/hr-hp)Inputs from 0.01 to 0.25Drive train horsepower lossAssumed 0 for engine comparisonTable 2.0 Bowling and Grippo program inputs(Refer Table 6.0 in Appendix D for imports) go in 1.0 Estimated MPG vs. BSFCThe specific fuel consumption of the engine should be a minimum to obtain high miles per gallon of fuel (from figure 1.0).The engines selected were further short listed considering the information available and ease for modification.142F Gasoline engineBrake specific fuel consumption = 480 g/kW-hDensity of gasoline = 2790.38 g/gal, 15480 g/2790.378 g/gal = 0.1720 gal0.1720 gal/1.341 hp-hBSFC = 0.1283 gal/hp-hHonda GX35Brake specific fuel consumption = 360 g/kW-hThis value in gal/hp-h = 0.0962 gal/hp-hMiles per gallon was estimated (assuming no power loss in drive train) for each engine while considering the mass of each engine.Estimated weight of vehicle without engine = 330 lbsWeight of vehicle with 142F engine = 335.5 lbs, this gives an estimated MPG of 790.84.Weight of vehicle with Honda GX35 = 333.8 lbs, this gives an estimated MPG of 1058.84.7Figure 2.0 MPG for 142F and GX35 enginesAlthough miles per gallon value would be lower when drive train pow er loss is considered, the engine was compared assuming a 100% efficient drive train.These calculations are based on gasoline fuel for engine comparison purposes. choose resolvents clearly indicate that the Honda GX35 is the most suitable engine for this system and also considering the reliability component of Honda further proves that this engine should be selected for this application.3.4 Honda GX35Main advantages of Honda GX35 engine 11 put brush up brake specific fuel consumptionMass is almost 2 kg less than 142FBetter reliability and it has been improved over the past 10-11 years.Over Head Cam engine Carrying out modifications on the cylinder head is easier.360o inclinableThe only disadvantage is that it consists of a carburetor. A fuel injection system would have been more fuel efficient but electronic fuel injection would also require an Engine management system and alternator which would add more weight to the vehicle. Therefore weight is less with carburetor.Performance c urvesCDocuments and SettingsPulsaraDesktopFYP RESEARCHcurve_GX35.gifFigure 3.0 Performance and fuel consumption curves 11Basic calculationsClearance Volume (Stock GX35)Swept Volume = 35.8 cm3, Compression ratio, rc = 81Compression ratio = Total Volume, (Vc+Vd)/Clearance Volume, VcClearance Volume, Vc = 5.114 cm3Brake mean effective pressure (BMEP), (Stock GX35)Maximum power output = 1.3 HP at 7000rpmL is displacement in liters, L = 0.0358 lBMEP = 67.44 lbf/in2Calculation of specific fuel consumption with ethanol without any system modificationsFuelNCV (KJ/l)NCV (KJ/gal(US))Gasoline31627.84119724.42Ethanol21229.4880362.34Table 3.0 Net calorific values by volume 1, 15BSFC with ethanol0.0962 gallons of gasoline = 119724.42 x 0.0962 KJ = 11517.45 KJTherefore BSFC of Honda GX35 engine with ethanol fuel = 0.1433 gal/hp-h(GX35 specifications in appendix C).3.5 ModificationsFigure 4.0 Engine modifications3.5.1 Mandatory modifications for ethanol combustionCarburetor modificationMain jet cha ngesSince the energy density of ethanol is lower than gasoline, the fuel/ pains ratio should be increased. The main jet orifice can be bored out to increase the size of the orifice by nearly 30% of the original size. The duck soup/fuel ratio for ethanol combustion should be 10.071. 4, 1Idle orifice changesWhen the throttle plate is at idle position, the air/fuel mixture is only allowed to enter the manifold through the idle orifice. The idle mixture screw could be loosened or orifice could be bored out to increase the size by 30% in order to provide sufficient ethanol to keep the engine running at idle speed. 4Overall engine and piping systemEthanol is a strong cleaning agent and has the ability to degrade certain engine move such as, natural rubber, plastics, and even metals over time. Therefore, all rubber and plastic components should be replaced by synthetic material. 4It is recommended to use neoprene hoses for the fuel delivery system. 4Durability of various plastics Ethano l vs. Gasoline in table 3.1in appendix D.3.5.2 Modifications for maximum fuel efficiencyCompression ratio alterationThis is discussed with detailed analysis in chapter 5.0Intake and exhaust optimizationThis is discussed with detailed analysis in chapter 6.0Starting systemAn electrical starter would be installed which would enable the driver to turn off the engine and coast after reaching a particular speed and restart later with ease.ChokeA manually meetled choke is better for ethanol engines and oddly for this competition. Therefore if the engine is equipped with an automatic choke it can be adapted for manual crack using a manual choke renewal kit.CHAPTER 4.0COMPRESSION RATIO ALTERATION4.1 IntroductionThis is the main advantage of using ethanol as fuel. The compression ratio can be increased up to 16-201 without engine knock. 20Increasing the compression ratio increases the thermal efficiency of the engine but it should only be increased to an extent to which the engine could oblige the pressure and temperature.Methods to increase the compression ratio 21Cylinder head and block can be shaved by milling (planning) the surfaces.Modify or change the piston head.Inlet conditions (High pressure, temperature etc)Reduce gasket thickness4.2 AnalysisFor this analysis, the combustion bedchamber of the engine was assumed to be cylinder shapedr = Bore/2 = 1.95cmXVC (Stock) = 5.114 cm3r2 X = 5.114X = 0.428 cmMilling the head/block or reducing thickness of the gasket would reduce X which would result in a smaller clearance volume, VC.A smaller clearance volume results in a higher compression ratio which also generates more power.Valve clearance for Honda GX35This is the maximum distance the valve travels beyond the engine head.Intake Valve clearanceExhaust Valve Clearance0.08 +/- 0.02mm0.11 +/- 0.02mmTable 4.0 GX35 Valve clearance 17The value of X after modifications must be great than 0.13 mm to avoid valve/piston collision.Let Y be the amount of head/block mill ed or reduced from gasketX = (4.28 Y) mmThere is no direct theoretical relationship between horsepower and compression ratio but the Bowling and Grippo program provides a rough estimate which was tabulated in table 6.1 in appendix D. 7For specific new fuel consumptionTabulated results can be found in Table 6.1 in Appendix DFigure 5.0 Compression ratio vs. reduction in combustion chamber height (Y)Figure 5.1 Estimated engine HP vs. reduction in combustion chamber height (Y)Figure 5.2 BSFC vs. reduction in combustion chamber height (Y)Figure 5.3 Estimated miles per gallon vs. reduction in combustion chamber height (Y)From research it was found that the compression ratio could be increased to 16-201 with ethanol fuel without knock problems but there was no credible information on how much compression the engine could withstand. Therefore, it was specified to increase the compression ratio only up to 121.This increase in compression ratio would result in an increase of 55 miles per gal lon (US)(Refer figures 5.0, 5.1, 5.2 and 5.3)4.2.1 Engine cyclic analysisFigure 6.0, P-V diagram for naturally aspirated Spark ignition engine 25Inlet conditions gouge (P) = 1 bar, Temperature (T) = 303 K, Ideal Gas constant (R) = 287 J/kg. K,Ratio of specific heats () = 1.4, CV = 717.6,For perfect gas,Where, is the total mass of charge mixtureFrom fuel consumption calculations using net calorific valuesFuel /Air ratio (FAR) of Ethanol = 1.49 x FAR of gasolineFAR (Ethanol) = 1/15 x 1.49 = 0.0993, whereFrom 1 2 (Refer figure 6.0)Isentropic compressionFrom 2 3 (Refer figure 6.0)Constant volume heat additionEnergy density of Ethanol = 30 MJ/kgMost small engines have thermal efficiencies between 40 and 45%. Therefore with a compression ratio of 121, transformation efficiency (Formation and combustion) can be assumed to be 45% to obtain an overestimate of the increase in pressure and temperature. 22Above calculations were repeated for the original compression ratio (8.01) of the stock e ngine which gave the following resultsCUsersPMGDesktopFYP RESEARCHT0512e0v.gifFigure 7.0 Thermal efficiency increase with increase in compression ratio, 23Assuming a conversion efficiency of 40% and an air/fuel ratio of 151Therefore, the peak in cylinder pressure has been increased by a factor of 1.64. This factor is also the factor of increase in force on piston, head, valves etc.Brake mean effective pressure (BMEP) is a valuable measure of the power of an engine to do work and is independent of displacement (Size of engine). 24The BMEP of the stock engine was 67.44 (from calculations under parametric study).Therefore, increasing the compression ratio has increased the capacity of the engine to do work significantly.CHAPTER 5.0INTAKE AND EXHAUST OPTIMIZATION5.1 IntroductionA pressure loop is created when an intake or exhaust valve is undetermined/ blockd. The ripple propagates through the vacuum tube at the speed of sound. When this wave encounters a change in cross sectional area, such as the end of the thermionic valve, a wave of opposite sign will be reflected which would travel back towards the port. Based on the time taken for this wave to return to the valve and also considering the open/close durations of the valves, the optimum aloofness for the holler can be calculated. This would increase the volumetric efficiency of the engine. 165.1.1 Optimum intake yell lengthExperiments have revealed that there is a significant gain in volumetric efficiency when the reflected compression wave returns when the piston is at a crank tip off of 90o. At this point the piston would be moving at maximum speed. Matching the time taken for the wave to return with engine speed, the required length of the pipe can be found. 16Velocity of wave = Distance/Time, (where distance = 2L)Time = 900/ RPM (revolutions/minute)(minute/60s)(3600/revolution) = 15/RPM16CDocuments and SettingsPulsaraDesktopFYP RESEARCHfluid0image1.gifWhere c is the speed of sound which depends o n the temperatureWhere = Ratio of specific heatsR = Ideal gas constantT = Temperature5.1.2 Optimum exhaust pipe lengthAt blow down (exhaust valve opens), a compression wave is propagates through the pipe and when it meets the end of the pipe an expansion wave returns back to the port. Experimentally it has been revealed that the optimum position of the piston when the wave returns is 120o. At this position the exhaust gas can be scavenged from the combustion chamber efficiently. 16Time = 1200/RPM (360/60) = 120/RPM16CDocuments and SettingsPulsaraDesktopFYP RESEARCHfluid0image4.gifGraphs were plotted using these formulaeA detailed calculation also considering the valve timing of Honda GX35 could be found under detailed calculations (5.2)Figure 8.0 Intake pipe length vs. engine RPM at different temperatures(Tabulated results in table 6.2 in appendix D)Figure 8.1 Exhaust pipe length vs. engine RPM at different temperatures(Tabulated results in table 6.3 in appendix D)5.2 Optimum pipe l ength calculations in detail5.2.1 Intake pipe length considering valve timingIntake valve opens at 10o before top cold centre (BTDC) and intake valve closes at 57o after bottom dead centre (ABDC). 18Duration of 247o , 18Intake valve opens once every two revolutions.Therefore (360 x 2 247) o = 473oAfter closing, the intake valve would open again after 473 crank angle degrees473o =Speed of sound at an intake temperature of 30oCRatio of specific heat, = 1.4 at 30oCDistance travelled is two times the pipe length,Therefore,The optimum pipe length for GX35 engine to run at 5100 RPM is 2.705 mDue to the space constraint of the engine compartment pipe length can be shortened by a factor of four, qualification it 0.677 m in length. By this method, the wave would travel up and down the pipe four times before the intake valve opens again. Although the effectiveness would be less, it would still arrive at the correct time to force more air into the cylinder.Using this result a custom intake pipe was designed with a length of approximately 0.5 m leaving the remaining 0.177 m for intake runners, carburetor, etc5.2.2 Exhaust pipe length using valve timingThere are various methods and theories used for calculating the exhaust pipe length. The intake and exhaust can be treated separately to find the optimum length for each pipe and also both can be treated as one system during valve overlap to gain an added advantage during the overlap menstruation.Method 1 (Considering exhaust system only)The reflected pulse could be set to arrive at the engine just as the exhaust valve starts to open, which would help to expel the exhaust gas without using up excess energy.Exhaust valve opens at 48o before bottom dead centre (BBDC) and exhaust valve closes at 28o after top dead centre (ATDC). 18Duration of 256o, 18Port opens/closes once every two revolutions. Therefore, exhaust valve opens 464 crank angle degrees after closingSpeed of sound, c at the exhaust will depend on the exhaust t emperatureThermodynamic calculations were continued from point 3 (Refer Figure 6.0) in order to calculate the temperature at blow down.,From 3 4Isentropic expansionThis length can be shortened by a factor of four allowing the wave to travel up and down four times before the valve starts to open, which gives 1.163 meters.Method 2 (Considering valve overlap period)If the reflected expansion wave reaches the opened exhaust valve just before closing but after the intake valve opens, the expansion wave will travel across the cylinder (since effective cylinder volume is small near TDC) through the intake port up to the intake atmosphere. This would result in an increased aspiration.Intake/exhaust valve overlap period of 38oBlow down shock wave leaves at 48o BBDC and the expansion wave must be set to return at around18o ATDC. 18This gives duration of 246o, 18Exhaust valve opens once every two revolutions.To obtain maximum volumetric efficiency by gaining advantage of the valve overlap peri od the exhaust pipe should be 2.46 meters in lengthThis can be shortened by a factor of two which would make the wave travel up and down twice before making use of the valve overlap period but this method may not be effective since the exhaust port will be open when the valve returns for the first time.5.3 Custom parts in the intake/exhaust systemIntake pipeThis pipe was designed considering the calculation results (figure 2.0) and compartment spaceLength is approximately 0.5 meters, (CAD drawing in appendix A)Exhaust pipeThis was designed considering the calculations (figure 2.1), compartment space and also the Shell Eco-Marathon rule which secerns that exhaust should be evacuated outside the vehicle but the pipe should not be longer than the bodyLength is approximately 1.5 meters, (CAD drawings in appendix A)Velocity stackFigure 9.0 Inlet flow 19This is a pipe with a sheer inlet which should be fixed to the end of the intake pipe. This would give a smoother flow of air into the intake pipe which would result in better atomization of fuel in the carburetor. Also this allows the full cross section of the intake pipe to be used whereas without a curved inlet, the flow area would be reduced due to the sharp entry. Therefore the velocity stack helps to aspirate more air into the system. 19(CAD drawing in appendix A)5CHAPTER 6.0FUEL DELIVERY SYSTEM6.1 IntroductionThe basic function of this system is to deliver the fuel to the carburetor. In regular vehicles, either mechanical or electric fuel pumps are used to pressurize and drive the fuel into the system. Stock GX35 engine uses gravity to pressurize the fuel when used in lawn mowers.The Shell Eco-Marathon rules state that electric fuel pumps are not allowed. 1Therefore the possible methods would beUsing a Mechanical fuel pumpUsing gravityPressurized fuel delivery system using compressed air6.2 Selection and designA mechanical pump would have to be powered from the engine output, which would result in an additi onal load on the engine. This would result in a reduction in specific fuel consumption.The pressure due to height may not be large enough due to the space constraint in the engine compartment if gravity is used. Also, the shell fuel tank could be pressurized up to 5 bar which makes the pressurized system ideal for this applicationFigure 10.0PRESSURIZED FUEL DELIVERY SYSTEM LAYOUTValve to drain the fuel (Shell requirement)Solenoid cut off valvePressure control valveA 1.5L pop bottle is used to store air at high pressure and air is regulated using a pressure control valve to control the pressure of air entering the fuel tank. This air at high pressure is used to push the fuel through the system.Pressure sens is positioned close to the fuel tank to indicate the pressure of air entering the fuel tank.An air pump (hand held or foot pump) can be used to pump in air through, the valve stem (No return valve).1.5 L pop bottles are rated at 72 psi, therefore it is recommended to pump the bot tle to approximately 60 psi.6.3 Advantages of this methodNo wasted load on the engine to drive a mechanical pumpLess weightLow costAlso, this is a proven method which has been used in successful endurance vehicles in past competitions. 2(CAD drawings can be found in appendix A)Figure 10.1 Screenshot from CAD model showing the fuel delivery systemCHAPTER 7.0DRIVE TRAIN7.1 IntroductionThe vehicle consists of three wheels, two in front and one at the back. The vehicle was designed to be a rear wheel drive and a chain is used to drive the wheel. Design and selection of transmission system and parts, supplement ratio calculations, overall system layout and basic stress analysis is discussed in this chapter.7.2 Transmission systemThere were few potential transmission concepts that could be usedContinuously Variable Transmission (CVT). 26Derailleur 27Manual two/three speed gear boxDirect drive system 2CVT is known to be more efficient than a manual gear box but after further review it wa s found that CVT is less efficient at low speeds. 41Derailleur system is highly efficient and simple but previous vehicles with this system had problems with the chain slipping out of the sprocket during gear change. 2Although a manual gear box is well suited for this system, it would add extra weight and also more moving parts results in additional power loss.Therefore a direct drive system with one gear ratio was selected as the most suitable transmission system.Main reasons behind selecting direct drive transmission systemHonda GX35 has relatively flat curves for torque, power and fuel consumption. The fuel consumption curve is almost flat from 3000 to 6000 RPM. Therefore the engine can run at a wide range of speeds and still supply adequate power with the same fuel consumption. (Refer figure 3.0)A manual gearbox would add extra weight and benefits of it would be negligible due to the linear performance curves.7.3 System layoutFew drive train system layouts were drawn in order to deal space for each part. The most suitable layout was selected and modified accordingly.FUEL TANKCLUTCHFigure 11.0 Selected layout(Initial concept layouts in Appendix F)Figure 11.1 Screen shot from CAD model of the propulsion system showing the layout(Overall CAD assembly and exploded drawings in appendix A)7.4 Gear ratioSince a direct drive system was selected, the drive train would have one fixed gear ratio from engine to rear sprocket.An overall gear ratio of 161 was chosen and calculations were carried out to verify that this ratio is suitable for our application.7.4.1 The torque required at the rear wheel to move vehicle from restRolling resistance,Where,= Coefficient of rolled resistancem = Total mass of the vehicleg = Acceleration due to gravityCoefficient of rolling resistance for pneumatic tires on a run dry surface can be approximated by the following equationWhere, P = Tire Pressure (bars)U = Vehicle velocity (km/h)Overall estimated mass of the vehicle = 140 kgMaximum tire pressure = 85 psi (5.8605 bar)Rear wheel diameter = 0.508 mTorque required to move the vehicle = Rolling resistance x driving wheel radiusThe efficiency of the drive train w