A SIMULATION STUDY ON PERFORMANCE AND EMISSION CHARACTERISTIC OF BIOGAS ENGINE CONVERTED FROM CONVENTIONAL DIESEL ENGINE

Abstract

This paper presents a simulation study on performance and emission
characteristic of a biogas engine by thermodynamic simulation software AVL Boost.
The original model of diesel engine was modified to reduce compression ratio and
mixture formation in order to operate with biogas fuel. The engine operating
parameters including air flow, brake torque and power, fuel consumption and
emissions were determined. The simulation results show that, when operating with
biogas, the NOx emission reduces significantly while the CO emission increases
compared to the case of diesel engine. The engine performance as brake power
reduces when the engine was simulated with biogas, however, the fuel economy
tends to improve. The effect of ignition timing on engine performance was also
evaluated. The results show that the optimized value of ignition timing for the
biogas engine should be adjusted between 11 to 19 crank angle bTDC.