Technical Paper
Influence of the Injection Timing on the Mixture Formation Process in a Spark-Ignition Hydrogen Fuelled ICE
2023-08-28
2023-24-0079
In the context of reducing carbon-dioxide (CO2) emissions, the increasing exploitation of renewable sources is expected to improve the availability of green hydrogen, which can be considered a valid alternative to gasoline and diesel fuels in the mobility sector (particularly for long-haul and heavy-duty missions). The air-hydrogen mixing plays a significant role, particularly in direct-injection spark-ignition engines. As a matter of fact, the onset of zones featuring an equivalence ratio greater than 0.5 should be avoided, since this would lead to an increased risk of self-ignition and NOx production. The presence of wide ultra-lean volumes (over the lean flammability limit) due to imperfect mixing is negative too, yielding to irregular combustion. Therefore, the calibration of the direct injection timing is a crucial task.