Date of Award

5-2008

Document Type

Thesis

Degree Name

Master of Science (MS)

Legacy Department

Mechanical Engineering

Advisor

Law, Harry

Committee Member

Haque , Imtiaz

Committee Member

Wagner , John

Abstract

Drag racing has been around since the 1950's and has become a very popular and very competitive sport. The difference between winning and losing can be hundredths and even thousandths of a second. Drag racing teams need every advantage they can get in order to excel in their field. On-track testing is very expensive and can consume large amounts of time and resources that a race team may not be able to afford.
One way to address this potential problem of high cost is by using computer simulation to show how your drag race car may perform at different tracks and how changes to your car may affect the performance at those tracks. A simulation could allow you to 'run' a test at different tracks without actually having to go to those tracks. While computer simulation can not completely replace real testing, it could save money and increase productivity at testing sessions. Additionally, the ability to generate vehicle dynamic responses specific to different tracks could be helpful in selecting vehicle parameters specifically for those tracks.
This thesis describes the development of a tool to study the vehicle dynamics of a front wheel drive drag racing car. A 5 degrees-of-freedom (DOF) model of the dynamic response of the vehicle on different track surfaces is developed and simulated in MATLAB and Simulink. The input to the simulation is a user-specified power spectral density (PSD) of the vertical road profile, tire-to-road adhesion level, and specific vehicle parameters. Outputs of the model include drag times, normal forces, longitudinal accelerations, heave, pitch angle, wheel slip, traction force, vehicle and wheel speeds, and engine RPM. Simulations are run comparing the effects of different road surfaces on the vehicle dynamic response and drag performance. Also, a gear ratio improvement loop is used to evaluate different gear sets on drag performance in an effort to improve the quarter mile time and trap speed.
The vehicle simulation shows that differing road surfaces have a large effect on vehicle dynamics and affect the overall performance of the vehicle on the drag run. The gear ratio improvement loop shows that quarter mile time improvements of 2% and trap speed improvements of over 4% could be achieved simply by using gear ratios that are chosen for a particular track surface. This simulation could produce beneficial and significant improvements in the drag racing world for teams looking for that extra edge on the competition. An overall improvement of 4% could be the difference between winning and losing.

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