喷氢正时及喷氢脉宽对于缸内直喷氢气发动机混合气形成及燃烧特性的影响

In order to study the effect of hydrogen injection strategy on the combustion characteristics of the in-cylinder direct injection hydrogen engine, a single-cylinder simulation model of the hydrogen engine was established by using three-dimensional simulation software, and the effects of different hydrogen injection pulse widths and injection timing on the in-cylinder mixture formation and combustion were investigated. The results show that: with the growth of hydrogen injection pulse width, the peak pressure in the cylinder rises gradually, but at the same time, the turbulent kinetic energy in the cylinder also rises, which makes it easier for abnormal combustion phenomena to occur; when the hydrogen injection pulse width is extended from 65℃A to 85℃A, the peak pressure in the cylinder is increased by 11.2% for every 5℃A of extension on the average, and at the same time, the engine has a better combustion characteristic at the hydrogen injection pulse width of 80℃A. When the hydrogen injection timing is When the hydrogen injection timing is earlier, the cylinder is prone to abnormal combustion phenomena such as vibration, when the hydrogen injection timing in -130° CA ~ -55° CA, can produce a larger peak pressure in the cylinder and no abnormal combustion phenomena, the maximum peak pressure in the cylinder is 5.9MPa; when the hydrogen injection timing is earlier, the ignition time of the cylinder gas movement is concentrated in the outside of the combustion chamber, in 140 ° CA and before the hydrogen injection, the cylinder gas mixing is not even enough to affect the stability of combustion. Affecting combustion stability.