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Design Team # 3 Shell Eco Marathon (Super-mileage Car)

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Presentation on theme: "Design Team # 3 Shell Eco Marathon (Super-mileage Car)"— Presentation transcript:

1 Design Team # 3 Shell Eco Marathon (Super-mileage Car)
Members: Hussain Abdellatif Sohaib Syed Alam Julius Mantolino Adam Procter Supervisor: Dr. Alex Kalamkarov

2 Outline Background Scope Design Requirements The Design
Current Project Status Future Considerations Design Requirements Check Budget Acknowledgements 2

3 Background Americas Shell Eco-Marathon Competition
not to go fast but to use least amount of fuel Houston, Texas – (March 29-April ) 2009 Dalhousie Team - 12th Place (819mpg) Core Super mileage Team with 4 volunteers Cover Steering Driver 3

4 Design Requirements Ultimate Goal: Achieve ≥ 900 mpg
Qualify/Compete for Shell Eco Marathon: Geometric Limitations 4 stroke IC Gasoline Engine Increased Fuel Efficiency Lighter Powertrain Lighter Chassis Lighter & More Efficient Wheels 4

5 The Design – Our Scope Engine Fuel Injection System Powertrain Chassis
Transmission Bearings Clutch Chassis Wheels 5

6 The Design -Challenge Rolling Resistance Aerodynamics
Reduction in weight More efficient wheels Aerodynamics Reduction in frontal area 6

7 Engine Direct Fuel Consumption Options Considered: Old 35cc Honda
Old 50cc XF Yamaha New 35cc Robin Subaru Honda 35cc [1] Robin Subaru 35cc [2] 50cc XF Yamaha 7

8 Engine Selected : 35cc Robin Subaru
- Selection Parameter 35cc Honda[1] 35cc Subaru[2] 50cc Yamaha[3] Weight [kg] 3.00 2.80 11.34 Displacement [cm3] 35.8 33.5 49 Max. Power RPM] 7000 7000 8000 Max. Torque RPM] 5500 5000 6500 Max. Power to Weight Ratio [HP/kg] 0.43 0.57 0.44 Past Experience Underpowered N/A Overpowered Engine Selected : 35cc Robin Subaru 8

9 Engine Modifications -Electric Starter One-way Needle Bearing
Reused electric motor from Yamaha Gear reduction 9

10 Engine Modifications -Muffler Requirement: Max. Noise Level <90 dB
Stock Muffler: Lower Efficiency Glass Pack Muffler: Perforated Design Packing diffuses sound Less restriction Glass Pack Muffler [4] 10

11 Fuel Delivery System Possible fuel delivery methods:
Carbureted Port Fuel Injection Direct Injection Direct Injection is not Viable: Requires mechanical fuel pump (competition rules) Complex 11

12 Selected: Port Fuel Injection
Fuel Delivery System -Selection Carburetor Port Fuel Injection Advantages No cost Time savings Controlled amounts of fuel Conversion kit can be readily purchased Disadvantages Low efficiency No control on optimum fuel consumption Cost (~$800) Needs pressurized system Calibration and fine tuning Selected: Port Fuel Injection 12

13 -Electronic Fuel Injection
Fuel Delivery System -Electronic Fuel Injection Replace carburetor Conversion kit purchased from Ecotron: Key components: Oxygen (O2) Sensor Fuel Injector Programmable Engine Control Unit (ECU) Fuel Pressurization System Throttle Body 13

14 -Electronic Fuel Injection
Fuel Delivery System -Electronic Fuel Injection Control parameters as required Engine Control Unit (ECU) Throttle Position Inlet Air Pressure Fuel Injector Inlet Air Temp. Exhaust Temp. Crankshaft Position Engine Kill Switch Programmable Control Parameters Sensors – Input Controlled Output Exhaust O2 Spark Timing 14

15 Fuel Delivery System -Pressurization Fuel Pressurization System [5] 15

16 Powertrain Transmits power from engine Require minimum power losses
Provide sufficient torque Best Efficiency Point (BEP) ∼ 5000 RPM Provided by bsfc curve To be verified with testing Calculate suitable gear ratio: 𝑉 𝑎𝑣𝑔 =15 𝑚𝑝ℎ=6.71 𝑚/𝑠 𝜔 𝑤ℎ𝑒𝑒𝑙,𝑎𝑣𝑔 =19.17 𝑟𝑎𝑑 𝑠 =183 𝑅𝑃𝑀 𝐺𝑅= ≅28 16

17 Transmission Type Selected : Direct Drive
Powertrain - Transmission Direct Drive Variable Transmission Advantages: Simple design Cheap Lightweight Vary the gear ratio to the wheel Change torque at wheel Disadvantages: Can’t run at BEP Start-up load Expensive Complicated and heavy Requires gear shifting Transmission Type Selected : Direct Drive 17

18 Powertrain Components: Gear Reduction Method Two Stages Bearing Clutch
18

19 Primary Stage Selected : Planetary Gearbox
Powertrain – 1st Stage Roller Chain Timing Belt Planetary Gearbox Advantages: Easy to design Cheap Light weight Compact Design High reliability Disadvantages: Weight Large sprockets Space Pulleys sizes Cost (~$800) Medium Weight Primary Stage Selected : Planetary Gearbox 19

20 Powertrain - Overall Planetary Gearbox for 1st stage
Purchase Neugart PLE60-20 Planetary Gearbox from Wainbee Ltd. 94% efficient 20:1 gear ratio Continuous torque 44 N.m. Roller Chain and Sprockets for 2nd stage 20

21 Powertrain - Overall Planetary Gearbox for 1st stage
Roller Chain and Sprockets for 2nd stage 21

22 Bearings Selected : Ceramic Ball Bearings
Powertrain - Bearings Ceramic (Si3N4) Ball Bearings [6] Steel Bearings Advantages: Significantly reduced weight; (0.5 x steel) 30% the friction of steel Provides smoother operation Cheap Disadvantages: Expensive (10 x price of steel) Heavier More friction Requires lubrication Bearings Selected : Ceramic Ball Bearings 22

23 Powertrain -Clutch Centrifugal [7] Friction Plate [8] 23

24 Clutch Selected : Centrifugal Clutch
Powertrain -Clutch Selection Friction Plate Clutch Centrifugal Clutch Advantages: Flexibility in engaging Less power losses Greater torque capacity Light weight Compact Automatic engagement Disadvantages: Heavier Space Risk of stalling   Power losses during slippage Spares Clutch Selected : Centrifugal Clutch 24

25 Powertrain -Torque Calculations Engine is not overloaded 25

26 30% weight reduction per unit length
Chassis -Selection Design Requirement: Lighter chassis Aluminum Alloy 6061-T6 Yield strength = 275 MPa Weight estimate entire car (with driver) ~ 90kg Withstand static load of 700N on roll bar Past team Selected 1’’ OD by 0.125” thick Cross section area = 0.34 in2 1-1/4’’ OD by 0.065” thick Cross section area = 0.24 in2 30% weight reduction per unit length 26

27 Chassis – Rear Loading Max. Stress: 55 MPa 27

28 Chassis – Side Loading Max. Stress: 75 MPa 28

29 Chassis – Pull Loading Max. Stress: 50 MPa 29

30 Chassis – Push Loading Max. Stress: 43.8 MPa 30

31 Wheels 3 wheels: 2 in front, 1 in back Front Wheel Design
Lighter No Internal Ratchet Back Wheel Design Internal Ratchet Heavier Back vs Front Wheel Assembly [9] 31

32 Wheels 3 wheels: 2 in front, 1 in back Front Wheel Assembly: Lighter
Past team Selected Front Wheels: Small (406 x 44c) Back wheels: Back Wheel Design Front wheels: Larger (700 x 25c) Larger (650 x 25c) Front Wheel Design Front Wheel Assembly: Lighter Larger Rim Size: Less Bearing Loss 32

33 Wheels Hubs & Spokes to be purchased
Incorporate Sprag Clutch in Back Wheel Disc Brakes: Reusing from past team Consistent brake performance Hubs & Spokes to be purchased 33

34 Wheels Past: Selected: Michelin road tires Continental GatorSkin tires
Higher inflation pressure 150 psi vs. 60 psi Lower rolling resistance Flat and puncture resistant Durable Michelin Tires [10] GatorSkin Tire [11] 34

35 Wheels 35

36 Project Status Purchased: Designed: Robin Subaru 33.5cc engine
Electronic Fuel Injection (EFI) kit PLE60-20 Planetary Gearbox Aluminum tubing for chassis Designed: Power Train Components Electric Starter Assembly Chassis Main Frame Body 36

37 Design Req. Check Achieved Already To Be Achieved:
Qualify/Compete for Shell Eco Marathon Geometric Limitations 4 stroke IC Gasoline Engine Lighter Powertrain (Centrifugal) Lighter Chassis (30% reduction) To Be Achieved: Increased Fuel Efficiency - to be confirmed with dyno Lighter & More Efficient Wheels Achieve ≥ 900 mpg - TBD 37

38 Future Considerations
Assemble Power Train Assemble Power Train, Steering & Cover onto Chassis Purchase Wheels & Wheel Components Obtain Engine Curves with Dyno: Carburetor Fuel Injection Fine Tune ECU Programmable Parameters Dyno Wheels 38

39 Budget Engine $425 Fuel Injection System $586
Drivetrain & Clutch (estimate) $2000 Chassis $500 Wheels $2500 Total (15% Contingency) ~ $7000 39

40 Acknowledgments We would like to thank: Dr. Julio Militzer
Dr. Alex Kalamkarov Albert Murphy Mark MacDonald Angus MacPherson Peter Jones Allison Chua, Drew Moores, Ryan Louie & Dainis Nams 40

41 Acknowledgements - Sponsors
We Thank Our Sponsors 41

42 References [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] D~ /continental-ultra-gatorskin-700-x-28-wire-tire.jsp 42

43 Questions ? 43

44 Back Up Material Engine Specs Load Torque Assumptions Bearings
Bearing, Output Shaft FEMS Starter Assembly FEM 44

45 Engine Specifications
45

46 Torque Calculations (1)
𝑇 𝑙𝑜𝑎𝑑,𝑤ℎ𝑒𝑒𝑙 = 𝑇 𝑟𝑜𝑙𝑙𝑖𝑛𝑔 + 𝑇 𝑑𝑟𝑎𝑔 𝑃 𝑙𝑜𝑎𝑑,𝑤ℎ𝑒𝑒𝑙 = 𝑇 𝑙𝑜𝑎𝑑,𝑤ℎ𝑒𝑒𝑙 𝑉 𝑟 𝑤 𝑇 𝑟𝑜𝑙𝑙𝑖𝑛𝑔 = 𝑟 𝑤 ( 𝐶 𝑟𝑟 𝑚𝑔) 𝑇 𝑑𝑟𝑎𝑔 = 𝑟 𝑤 (0.5 𝜌𝐶 𝐷 𝑉 2 𝐴) 𝐶 𝑟𝑟 = 𝑝 𝑉 𝑝−𝑡𝑖𝑟𝑒 𝑝𝑟𝑒𝑠𝑠𝑢𝑟𝑒 𝑖𝑛 𝑏𝑎𝑟𝑠 𝑉−𝑐𝑎𝑟 𝑣𝑒𝑙𝑜𝑐𝑡𝑖𝑦 𝑖𝑛 𝑘𝑝ℎ 𝐶 𝐷 =0.4 [ref] – common CD used in old 90’s cars 𝑚=150𝑘𝑔 - the max. allowed in competition 𝑟 𝑤 =0.35𝑚 𝐴= 𝑚 2 - frontal area of around (19inx28in) 𝜌−𝑎𝑖𝑟 𝑑𝑒𝑛𝑠𝑖𝑡𝑦 𝑜𝑓 𝑘𝑔/ 𝑚 3 𝑝=130 𝑝𝑠𝑖=8.96 𝑏𝑎𝑟𝑠 46

47 Torque Calculations (2)
47

48 Torque Calculations (3)
𝑇 𝑐 = 𝜔≤ 𝜔 𝑒 −𝑐𝑎𝑠𝑒 1 𝑇 𝑐,𝑚𝑎𝑥 𝜔> 𝜔 𝑒 , 𝑇 𝑒 > 𝑇 𝑐,𝑚𝑎𝑥 −𝑐𝑎𝑠𝑒 2 𝑇 𝑐,𝑚𝑎𝑥 𝜔> 𝜔 𝑒 , 𝑇 𝑒 < 𝑇 𝑙𝑜𝑎𝑑 −𝑐𝑎𝑠𝑒 3 𝑇 𝑒 𝜔> 𝜔 𝑒 , 𝑇 𝑒 < 𝑇 𝑐,𝑚𝑎𝑥 −𝑐𝑎𝑠𝑒 4 𝑇 𝑐 < 𝑇 𝑓,𝑚𝑎𝑥 −𝑐𝑎𝑠𝑒 5 𝑇 𝑐,𝑚𝑎𝑥 =𝑛 𝑟 𝑜 𝜇𝑚 𝑟 𝑠 𝜔 2 − 𝜔 𝑒 2 𝑇 𝑓,𝑚𝑎𝑥 =𝑛 𝑟 𝑜 𝜇 𝑝 𝑚𝑎𝑥 𝐴 𝑚 = g, 𝑛=2   𝑟 𝑜 =38.6 𝑚𝑚 𝑟 𝑠 =24.9 𝑚𝑚, 𝑐=1 𝑚𝑚 𝜇=0.25, [ref] 𝑝 𝑚𝑎𝑥 =1030 𝑘𝑃𝑎 [ref] 𝐴= 𝑚 2 𝑇 𝑓,𝑚𝑎𝑥 =21 𝑁𝑚 Engagement speed Slip Period Max. Clutch Torque Clutch “Bites” Clutch transmits engine torque 48

49 Bearings 49 Ceramic (Si3N4) Ball Bearings Steel Bearings
Advantages: Significantly reduced weight; density of Si3N4 is 3.2 g/cm3 versus 7.8 g/cm3 of steel Co-efficient of friction is 30% that of steel Less lubrication required Can operate at higher speeds (20% to 40% higher) Smoother operation because modulus of elasticity higher (stiffer) than steel; 320 GPa vs 200 GPa – less deformations leading to less vibrations Cheap Better impact loading handling Disadvantages: Expensive (10 times the cost of steel bearings) Heavier Higher co-efficient of friction Need for lubrication More vibrations and rocky operation Ball Bearings Selected : Ceramic Ball Bearings 49

50 Power Train Stresses 50

51 Starter Mount Stresses
51


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