http://www.sdsu-http://www.sdsu-cav.comcav.com

From Left to Right: Adam York, Brian Brink, Betty Jo, Mitchell Greene, Marshall Noble. (NOT

PICTURED): Stephanie Jacobs

Project Team: Project Team: Mitchell Greene, Stephanie Jacobs, Betty Jo, Marshall Noble, Adam YorkMitchell Greene, Stephanie Jacobs, Betty Jo, Marshall Noble, Adam YorkAdvisor:Advisor: Ken Gamble Ken Gamble

As part of the Mechanical Engineering program at San Diego State University, it is required that all students enroll and complete ME490, but what exactly is this educational course? ME490 is a year long (two semester) course broken down into two separate courses: ME 490A and ME490B. The overall objective of the course is to apply the engineering principles and the design techniques learned in prior course work to a “real world” engineering-like setting. More specifically, these techniques and principles will be utilized in designing, building, and testing of an engineering system. A single project is completed in this two-course sequenced and is judged on the presentation of an oral and written report. In addition, issues related to ethics and engineering practice are discussed.

Our team consists of five Mechanical Engineering Students: Marshall Noble, Mitchell Greene, Betty Jo, Stephanie Jacobs and Adam York along with our faculty advisor Ken Gamble. Our ultimate Goal is to use compressed air as a fuel source to power a light weight vehicle.

INTRODUCTIONINTRODUCTION

DESIGN SPECIFICATIONSDESIGN SPECIFICATIONS•Maximum speed of 10 MPH

•Driving Range of 9 holes of golf (Approx. 2 Miles)

•Decrease Overall Golf Cart Weight

FINAL DESIGN & ASSEMBLYFINAL DESIGN & ASSEMBLY

TOP LEFT: Exploded View of Assembly in TOP LEFT: Exploded View of Assembly in SOLIDWORKSSOLIDWORKS

TOP RIGHT: Assembly in SOLIDWORKSTOP RIGHT: Assembly in SOLIDWORKS

BOTTOM: Fabricated Assembly in existing BOTTOM: Fabricated Assembly in existing differentialdifferential

DESIGN CONCEPTDESIGN CONCEPTOur first concept of this project was to use the golf cart as our vehicle and take out the electric motor where the differential is located. The existing differential is attached to the rear axle. In order to drive the differential we would need a coupler that meshes with the existing spline. The electrical motor has a shaft and coupler that was once attached to the gear of the differential. Our team decided to re-use this coupler. We decided to have the shaft as an adapter for our air motor to the differential. We used a hydraulic press machine in order to press out the shaft and coupler that was inside of the electric motor. The air motor acquired for the project is small enough to be directly mounted to the existing differential. To do this a mounting plate was fabricated out of two steel plates, one which would be directly bolted to the motor, the other directly bolted to the differential. A Chromoly Steel tube would be present in between the two steel plates to house the shaft and the coupler.

Shaft & Coupling Spline from Electric MotorShaft & Coupling Spline from Electric Motor

Schematic of air line and pneumatic component assemblySchematic of air line and pneumatic component assembly

TESTING & RESULTSTESTING & RESULTS

ACKNOWLEDGEMENTSACKNOWLEDGEMENTSWe would like to thank the following companies for their continued support and

contributions to our project.

SPEED TESTING PROCEDURESPEED TESTING PROCEDURE

1. Affix reflective tape on the wheel as your point of reference

2. Point the Stroboscope Tachometer beam toward the reflective tape.

3. Use adjustment knob to adjust the rate of the strobe flashes until it appears that the point of reference is no longer moving.

4. Read and Record the RPM value on the Stroboscope’s LED display.

5. Use RPM values to calculate the “free” traveling speed.

Pred. P N ω V VNmot

or

PSI PSI RPM Rad/sFt/s

MPH Rad/s

30 50196.

6 20.59 15 11 2,446

25 60199.

9 20.93 16 11 2,487

30 70277.

9 29.10 22 15 3,457

50 80291.

0 30.47 23 16 3,620

55 90317.

0 33.20 25 17 3,943

60100

329.4 34.49 26 18 4,098