Student: Jacob Yordy

Mentor: Charles Pringle


This project’s goal was to add a clutch system to an electrical vehicle at Central Washington University. The project’s second goal was to have the clutch system improve the electrical vehicle’s fuel economy for Electrathon events. Electrathon uses an equivalent mpg formula to determine an electrical vehicle’s “fuel economy.” Based on the amount of energy in kilo-Watt hours in a gallon of gas, Electrathon assumes each car uses 0.026 gallons of “gas” in the hour long race and the mpg value given to an electrical vehicle is based on the distance the vehicle travels in the race. Analyzes and problem solving showed that only a lightweight clutch system was going to effectively increase the fuel economy of the small electrical vehicle.
A one-way clutch was purchased. Then a hub was manufactured, and the clutch was pressed into the middle of the hub, then screws held the clutch system up against a sprocket on the driven shaft. This clutch system allowed the electric motor to drive the vehicle forward. When power is no longer being delivered from the motor, the clutch system allows the vehicle to “coast” forward. This idea of covering more distance with the same amount of input energy is what makes the addition of a one-way clutch system so useful.
The clutch system proved to add as much as 5 mpg (6% increase) to the electrical vehicle’s fuel economy. In a full speed test, the vehicle coasted 48 more feet on average when the clutch system was equipped.


2 thoughts on “Electrical Vehicle Clutch Project”

  1. Jacob,
    Great project, that really improves the EV. Where did you end up testing the car? Were you able to find a hill in Ellensburg to use?


    1. Hey Kelson,
      I live on campus and unfortunately I was in my hometown when I got the email from CWU Housing asking me to restrict my travel. Testing hasn’t been completed because of the restrictions. I would like to find a hill in Ellensburg in June to complete the coasting test, but I’m not counting on it. I just need a hill that’s at least 3 meters high and transitions into level ground, or at least close to level ground. I have a hill picked out in my hometown that appears to be the perfect match.

      The anticipated results were calculated through an analysis that made use of conservation of energy principles from Technical Dynamics. The results of the analysis are only as good as the assumptions put into them (i.e. completely level ground after the bottom of the hill). There were not enough givens given for the coasting equation so a reasonable (researched) deceleration value had to be chosen for both the “clutch on” and “clutch off” scenarios. I would like to do the testing because although I’m confident the clutch will be successful, the success can’t be proven without live tests. Virtual tests won’t suffice here. Thanks for the interest and inquires Kelson.

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