Performance Study for Miller Cycle Natural Gas Engine Based on GT-Power

Abstract

—In order to improve the thermal efficiency of natural gas engine and reduce the NO x emission from engine, this paper presented the technical route which applied Miller cycle to turbocharged lean-burn natural gas engine. GT-Power software was used to model the turbocharged natural gas engine, and simulation research based on Miller cycle was performed according to various engine loads in the engine speed range of 2000-5000rpm. The simulation results showed that, under part load (50% of the engine full load) operating conditions of the turbocharged lean-burn natural gas engine, compared with Otto cycle, Miller cycle can reduce the brake specific fuel consumption (BSFC) and NO x emission. Under high load and low speed as well as moderate load and high speed operating conditions, Miller cycle can effectively reduce the BSFC. Under high load and low speed or high speed operating conditions, the NO x emission can be reduced apparently.