Numerical and experimental analysis on the effects of turbocharged compressed bio-methane-fueled automotive spark-ignition engine

Abstract

The implementation of recent emission norms has caused the automotive industries to develop advanced technologies for gaseous fuelled SI engines. This research focused on the comparison of turbocharged Compression Ratio (CR) 10.5:1 and naturally aspirated (NA) 12.5:1 for Compressed Bio-Methane (CBM) fuelled SI engine. The original port fuel injected automotive Compressed Natural Gas (CNG) Spark Ignition (SI) engine with 15.5 kW at 3400 rpm was made to function with CBM fuel under full throttle conditions at given CR. Also, two turbochargers T1 and T2 were analysed and validated using ANSYS turbo-machinery numerical package. T1 generated a higher-pressure ratio than T2 and was preferable. The simulation study outcomes infer that entropy generation for T1 at a 1.3 bar is less than 1.5 bar gave a better transient response. The experimental comparison was made between CR of 10.5:1 turbocharged and naturally aspirated CR of 12.5:1. At CR of 10.5:1, 1.3 bar boost pressure, brake power increased by 19.3%, reduced fuel consumption by 10.1%, and reduced hydro carbon (HC) and Carbon monoxide (CO) emissions 42.9% and 38.3%, when compared to NA CR of 12.5:1. On the whole, the downsized CR of 10.5:1 turbocharging exhibit better performance and reduced thermal loading when compared to higher CR of 12.5:1.