Output Performance Characteristics of Auxiliary Power Units with Single-Cylinder Diesel Engines by Replacing the Magnetic Material of Generator Rotor

This is a comparative experimental study on the power generation output characteristics of auxiliary power units (APUs), with different permanent magnet materials, for trucks and special vehicles applications. The efficiency of the generator, rotor speed, torque, changes in power generation output, current, and voltage were compared and analyzed with different permanent magnet materials on the rotor. The permanent magnets composed of NdFe38 and Sm2Co17 were assembled on the generator rotor (flywheel), and their output performance characteristics were compared. The experimental results showed that efficiency is slightly higher when Sm2Co17 was installed. Moreover, when power is generated at the operating condition of the APU system, comparative tests for the rotational speed of the flywheel-mounted rotor showed that the speed of the NdFe38 permanent-magnet rotor was lower by 400 rpm. The application of NdFe38 can reduce the speed of the APU system, fuel consumption (by 5%), and noise level; this result is expected to be useful for design margins on the power generation output of vehicles in the future.