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Effect of drivetrain set up on acceleration, torque, shifting and track times

Abstract
Every year SAE International organise an international competition to design and race a formula style race car called Formula SAE. The last time WESMO sent a car to competition was in 2018 and the 2018 car had gearing that was very short geared. This resulted in the driver having to constantly change gears, due to the final drive gear ratio being too high. The objective of this thesis was to research into potential way to increase the performance of the future WESMO cars through research into how to the effects of tuning the drivetrain along with potential areas for redesign with the gaol of producing a car that can complete the acceleration event in less than 3.8 seconds. Where practical the majority of the drivetrain components will be retained from the 2018 design,. Through a combination of optimising the drivetrain gear ratio, researching into new tyres as well as incorporating more carbon into the drivetrain design the proposed car could potentially meet that goal. The incorporation of carbon driveshafts as well as carbon rim shell both increases the efficiency of the torque transfer across the drivetrain as well as reduces the overall weight of the drivetrain. Optimising the gear ratio results in a reduced tendency to wheelspin and minimal shifting required during the acceleration run, while still maintaining high torque at the wheels. Future WESMO teams should also design the car around incorporating 7.5inch wheels, since changing from 6-inch to 7.5-inch wide tyres gives a noticeable increase in traction. The two best options for changing the tyres depend on the situation of future WEMO teams. Changing to 16-inch wheels will give better torque transfer to the wheels and reduces the Unsprung weight of the car but will require extensive redesign of the suspension on the car due to the different outer diameter of the tyre. Changing to the 18x7.5-inch tyres will increase the traction of the car, but also slightly increase the weight, however does not require as extensive of a redesign.
Type
Thesis
Type of thesis
Series
Citation
Date
2021
Publisher
The University of Waikato
Rights
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