ShellEco-marathonOBJECTIVE

The Shell Eco-marathon competition challenges students to

design, build, and test an energy efficient gasoline-powered

vehicle for the competition in Detroit, Michigan on April 9

through April 12, 2015. Students go through the design and

build process with a focus on energy efficiency.

SCHEDULE

1. Safe

2. Reliable

3. Durable

4. Fuel Efficient

5. Easy to Control/Operate

6. Aesthetically Pleasing

7. Comfortable

8. Simply Designed

9. Within Budget

VEHICLE STATSWEIGHT

Total Vehicle Weight: 154 lbs

Frame: 20 lbs

Steering & Controls: 25 lbs

Engine & CVT: 35 lbs

Body: 20 lbs

Miscellaneous: 54 lbs

DIMENSIONS

Vehicle Length: 9 ft 2 in

Frame Height: 26 in

Frame Width: 21 in

Track Width: 35 in

ENGINE

49cc Honda Metropolitan Scooter

Single Cylinder 4-Stroke

Compression Ratio 10.1:1

DRIVETRAIN

Stock Scooter CVT

Attached Sprocket & Chain

FRAME DESIGNThe riveted aluminum frame was a new design this year. 6061-T6 aluminum tubing was chosen as the frame

material instead of steel for weight savings. The joints were riveted to retain the material strength

compared to a welded design. The frame was the area of greatest focus as it would be the base for the rest

of the vehicle and included many of the main factors considered in safety. The vehicle had no suspension as

comfort was not a priority. ⅛” structural cherry-Q rivets were used for their strength and vibration resistant

qualities.

A 49cc 2013 Honda Metropolitan scooter engine was used from the

2014 vehicle. The team disassembled the engine to repair cylinder

and piston damage. The CVT from the scooter was left as-is and a

bicycle chain was run from a sprocket on the output of the CVT to a

sprocket on the 20” bicycle wheel. A bicycle type spring chain

tensioner was also utilized.

CLIENT VALUES

ENGINE & DRIVETRAIN DESIGN

The body is a painted carbon fiber shell. Two layers of 3K 2x2 Twill 199GSM Aero

50 inch carbon fiber were laid over a custom foam mold. The body was sanded

and cut before painting. The benefits of carbon fiber outweighed those of

fiberglass in all regards except cost and was within the budget constraints. The

side and front windows were made from 0.030” and 0.060” polycarbonate

sheets respectively that were riveted to the body. The cockpit door design used

a piano hinge and a cabinet roller latch.

BODY DESIGN

The steering system allows for a turning radius well

within the required 8 m radius. The design of the

uprights gave the vehicle Ackermann steering and

adjustable camber. The front and rear brakes were

separately activated with foot pedals. The starter

switch, ignition button, horn button, and throttle

paddle were mounted on the steering wheel.

STEERING & CONTROLS DESIGN

FUEL SYSTEM DESIGN

Note: Testing the engine on the dynamometer was not completed due to time constraints

FRAME FEA

Maximum Stress: 2,129 psi

(6061-T6 Aluminum Tensile Yield Strength: 40,000 psi)Maximum Displacement: 0.016 in

RIVET TESTINGFive T-shaped test pieces were created to simulate an unsupported node. Weights were used to test the

tube bending and shear failure of various rivet types, and deformation was recorded using a dial

indicator.

BUDGET & SPENDING

TEAM 15Joyce Atadero

Amanda Doolittle

Brian Nault

Alex Weiss

Acknowledgements:Dr. Martin Morris - Client

Dr. Richard Johnson - Advisor

Jon Kellogg

Dave Miller

Gayle Deynzer

DRIVING STRATEGYThe strategy to conserve fuel was to accelerate up to approximately

25 mph and then turn-off the engine to coast down to approximately

10 mph, preferably on downward slopes and turns, such that the

overall average speed of the vehicle was 15 mph during the run.

The fuel delivery system needed to be redesigned to comply with

competition rules for fuel injected engines. Instead of an electronic

fuel pump which is not allowed, a pressurized air tank and regulator

system was designed to pressurize the fuel bottle at the starting line

to the stock fuel injector pressure of 43 psi.

Creo Frame Model Frame During Construction

Shell Eco-marathon Competition: April 9-12, 2015 Location: Detroit, MI

Note: the 1/8” Cherry Q Structural Rivets did not fail during testing at the maximum weight available

Photo Credit: Bryan Mitchell/AP Images for Shell