Setup, Calibration, and Analysis of a Dynamometer for Measuring and Optimizing Performance of Small Gasoline Engines

Abstract

This paper describes efforts to set up, troubleshoot, and utilize the MAE department’s eddy brake engine dynamometer (“dyno”) to collect performance data for the Triumph Tiger Cub motorcycle. The goal of this work is to contribute to a knowledgebase on the motorcycle and small gasoline internal combustion engines in general in support of Princeton’s freshman seminar, FRS 106: Art and Science of Motorcycle Design. The motivation behind this research is to understand the engine’s torque, power, efficiency, fuel consumption, and emissions. The importance of this work today stems from an interest in sustainable combustion technologies and a desire to reduce transportation-related greenhouse gas emissions. In order to better understand they dynamometer’s operation, a 0.5-horsepower DC motor stood in for the Triumph engine during much of this research because it has a simple and predictable speed-torque relationship. An adjustable test stand and shaft adapter was designed to couple the motor to the dynamometer. It was an essential tool for calibrating the instrumentation and cleaning their noisy outputs, which was a significant portion of this work. The speed-torque data collected from the DC motor allowed for an interesting comparison with its ideal performance and provided critical insight into the dynamometer’s limitations, especially internal friction. A large part of this work involved retooling, repairing, and restoring a 1957 Tiger Cub engine for eventual dynamometer testing. To support this testing, a detailed modeling software was used to simulate the engine’s performance and provide a basis for modification and optimization in subsequent research. The results of that simulation are discussed in context with basic combustion engine theory. Finally, this report proposes areas for further research for FRS 106 and future MAE independent work.