Estimating the charge burning velocity within a hydrogen-enriched gasoline engine

This paper proposed a feasible method for estimating the turbulent burning velocity of gasoline/hydrogen blends in a spark-ignited (SI) engine based on the cumulative heat release fraction, engine speed and engine geometry. The experiment was conducted on a naturally-aspirated port-injection gasoline engine equipped with a hydrogen injection system. The engine was run at 1400 rpm with different loads and hydrogen volume fractions in the intake gas. The test results showed that the addition of hydrogen benefited increasing the burning velocity and advancing the relevant crank angle for the peak burning velocity, due to the high burning and diffusion velocities of hydrogen. At 1400 rpm, a manifolds absolute pressure of 61.5 kPa and stoichiometric conditions, the peak burning velocity was raised from 11.6 to 12.3 and 14.6 m/s, and the relevant crank angle for the peak burning velocity was advanced from 21.0 to 14.0 and 8.6 oCA when the hydrogen volume fraction in the intake increased from 0% to 3% and 6%, respectively. Moreover, the effect of hydrogen addition on enhancing the burning velocity of a gasoline engine was more pronounced at low loads than that at high loads.