Performance and Sensitivity analysis of Factors Affecting NOx Emissions from Hydrogen Fueled SI Engine

Abstract

An Analysis of Variance (ANOVA) sensitivity analysis using suitable MATLAB code on
the factors affecting oxides of Nitrogen (NOx) emissions of a hydrogen powered 4-stroke,
water-cooled spark-ignition engine was conducted in this work. This was done using
specialized engine performance and emission simulation software. The parameters studied
were the engine speed, air-fuel equivalence ratio, spark plug location in addition to some other
combustion parameters like combustion duration, heat loss besides some other useful
performance parameters. It was found that NOx formation is minimum at peripheral spark
location, slightly lean (PHI=0.9), and less advance timing is needed. Further, based on
ANOVA analysis, the combination of engine speed and spark location has more significance
(effect based on P-value) compared with engine speed and equivalence ratio. The combination
of engine speed and ignition timing has more significance (effect based on P-value) compared
with engine speed and equivalence ratio. Also found that NOx emissions behavior is more
clear at lean mixture (PHI = 0.7), central spark location (XSP = 0.5) and retarded ignition
timing (IGN near zero).