Novel Approaches to Improve the Performance of a Single Cylinder Engine by Turbocharging, Supercharging and Turbo-Compounding – A Comparative Study

Abstract

Abstract Designers find it extremely challenging to enhance the performance of single-cylinder engines. Since the exhaust flow is intermittent, single-cylinder engines available in the mass market are seldom turbocharged despite turbocharging being a staple technology in other multi-cylinder engines. Hence, almost one-third of the fuel energy is lost in the exhaust, reducing the performance of the single-cylinder engine. In the current work, the authors explore novel approaches to charge a single-cylinder diesel engine and extract power from the pulsated exhaust flow. Also, the authors compare the novel approaches. In the first approach, an exhaust plenum was employed to mitigate the exhaust flow pulsations to turbocharge the single-cylinder engine. In the second approach, a supercharger was employed to charge the engine and an impulse turbine was compounded to extract energy from the pulsated exhaust flow. One-dimensional simulation results indicated that turbocharging and supercharging with impulse turbine compounding significantly improved engine performance. With turbocharging, the brake power output from the engine increased by 26.3%, the airflow rate increased by 71%, and brake thermal efficiency increased by 1.5%. With supercharging and impulse turbine compounding, the brake power output increased by 41.8%, the airflow rate increased by 62%, and the brake thermal efficiency increased by 5.3%. Both novel approaches improved the performance of the single-cylinder engine significantly. The novel supercharging and impulse turbo-compounding approach provided superior results compared to the novel turbocharging approach. Thus, a comparative study of turbocharging, supercharging, and turbo-compounding was carried out and detailed in the present work.