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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. INTRODUCTION From Left to Right: Adam York, Brian Brink, Betty Jo, Mitchell Greene, Marshall Noble. (NOT PICTURED): Stephanie Jacobs • DESIGN SPECIFICATIONS • Maximum speed of 10 MPH • Driving Range of 9 holes of golf (Approx. 2 Miles) • Decrease Overall Golf Cart Weight DESIGN CONCEPT Our 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. FINAL DESIGN & ASSEMBLY Shaft & Coupling Spline from Electric Motor TOP LEFT: Exploded View of Assembly in SOLIDWORKS TOP RIGHT: Assembly in SOLIDWORKS BOTTOM: Fabricated Assembly in existing differential Schematic of air line and pneumatic component assembly ACKNOWLEDGEMENTS We would like to thank the following companies for their continued support and contributions to our project. http://www.sdsu-cav.com Project Team: Mitchell Greene, Stephanie Jacobs, Betty Jo, Marshall Noble, Adam York Advisor: Ken Gamble TESTING & RESULTS • SPEED TESTING PROCEDURE • Affix reflective tape on the wheel as your point of reference • Point the Stroboscope Tachometer beam toward the reflective tape. • Use adjustment knob to adjust the rate of the strobe flashes until it appears that the point of reference is no longer moving. • Read and Record the RPM value on the Stroboscope’s LED display. • Use RPM values to calculate the “free” traveling speed.