Development of a Rotary Screw Compressor for Electric Truck Air Brake and Suspension System

This article describes the development of a low-cost rotary screw compressor technology to meet the requirements of a mini air compressor application for electric vehicle (EV) air brake and suspension systems. An existing rotor profile and size was initially used to build an “Alpha” compressor prototype. This was tested to provide data for analysis and numerical simulation to determine a smaller rotor size, rotor profile, and more efficient overall package for hybrid/EV air brake and suspension applications. From the “Alpha” prototype testing and analysis, the author identified the root causes of lower energy efficiency. To address these deficiencies and develop a foundation for an optimized solution for the intended application, the author developed a clean sheet design. A smaller diameter rotor set with high tip speed was developed using parameter calculations, working process simulation, and prototype test data analysis. By incorporating an innovative J-profile rotor screw lobe design, “VMAC” created a set of small rotary screw rotors that are optimized for a reduced air delivery rate, high-pressure ratio, and compact size while achieving a high energy efficiency target. Through testing, the compressor has proven to significantly save energy compared with the other compressor technologies. Endurance testing results prove that the developed compressor maintains the high-reliability advantage of the screw compressor technology. The compressor development has utility in electric buses and electric trucks due to its high-pressure capability that supplies high energy density to allow for smaller pressurized air tanks and a boost mode for rapid air recharge.