The Effect of Ignition Timing on the Emission and Combustion Characteristics for a Hydrogen-Fuelled ORP Engine at Lean-Burn Conditions

The application of hydrogen fuel in ORP engines makes the engine power density much higher than that a reciprocating engine. This paper investigated impacts combustion characteristics, energy loss, and NOx emissions hydrogen-fuelled by ignition timing over various equivalence ratios using simulation approach based on FLUENT code without considering experiments. simulations were conducted under ratio 0.5~0.9 −20.8~8.3° CA before top dead centre (TDC). was operated 1000 RPM wide-open throttle condition which around maximum torque. results indicated significant early restrained flame development chambers due to special relative positions systems chambers. In-cylinder pressure evolutions insensitive ignition. start earliest −17.3° for individual ratios; correlations durations dependent timing. Combustion less sensitive range −14.2~−11.1° TDC. minimum heat release rates 15 J·(°CA)−1 22 0.5 0.9, respectively. Indicated thermal efficiency 41% scenarios, it significantly affected late Energy loss cylinder walls exhaust 10~16% 42~58% total energy, emission factors