To explore the effect
of hydrogen blending on the combustion of
a gasoline direct injection engine, a three-dimensional model of the
engine is built. The effects of some hydrogen volume fractions (HVFs)
and ignition timings (ITs) on the engine performance parameters are
studied. Furthermore, the microstructure and mechanism of combustion
are analyzed. The simulation results reveal that when the gasoline
engine is blended with hydrogen, the active hydroxyl radical concentration
increases, and the combustion process is accelerated. When the IT
is fixed, with the HVF rising, the peak heat release rate and cylinder
pressure will increase. The ignition delay, combustion duration, and
crank angle when cumulative heat release reaches 50% decrease. Additionally,
the autoignition is shifted to an earlier time as the IT advances.
Under the studied conditions with the increase in the HVF, the knock
resistance is enhanced because hydrogen has a high knock resistance
and octane number.