Experimental Research on the Effect of Excess Air Ratio on Turbocharged Lean-Burned CNG Engine

Abstract

Experimental research on the effect of excess air ratio on dynamic and emission performance of turbocharged lean-burned CNG engine. The 12 test conditions contain engine speeds of 1300r/min, 1600r/min, and 1900r/min, with 25%, 50%, 75%, 100% load separately. When keeping other combustion boundary conditions unchanged, the excess air ratio has little effect on engine output torque at almost all test conditions, but has obvious effect on CH4 and NOx emission. With the excess air ratio increasing, the emission of CH4 has increased while the NOx emission has decreased significantly. When the λ value is in the range of 1.4-1.45, the emission level is lower.