Numerical Simulation of the Effect of In-Cylinder Water Spraying on the Knock and Combustion Characteristics of a Hydrogen-Argon Oxygen Engine

Fossil fuel depletion and air pollution have accelerated the transformation and upgrading of the internal combustion engine industry. The argon-oxygen atmosphere engine has the advantages of “zero emission” and high thermal efficiency, but the knocking problem constrains the engine to operate at a lower compression ratio. In this paper, the effect of water spraying technology on the knocking combustion and combustion characteristics of a hydrogen-argon oxygen engine is investigated by numerical simulation. A one-dimensional thermodynamic model and a three-dimensional numerical model of the hydrogen-argon oxygen engine are established and validated by aligning the model with the data of the real engine. Firstly, investigate the effect of in-cylinder water spraying timing on knock suppression and combustion characteristics of hydrogen argon oxygen engines. 570 ° CA to 600 ° CA is the optimal water spraying timing range for suppressing knock. When 570 ° CA is sprayed, the atomization effect of droplets in the cylinder is good, and the combustion and power characteristics are significantly improved. At this time, the water spraying IMEP increases by 14.45%. Therefore, 570 ° CA is selected as the optimal spraying timing. On this basis, the effect of in-cylinder water spraying mass on the knock suppression and combustion characteristics of the hydrogen-argon oxygen engine is further investigated. When the water spraying mass reaches 24 mg, the knock intensity KI droppes to 0.170 MPa, and the knock phenomenon has been effectively suppressed. There is no obvious numerical change in KI when the water spraying mass continues to increase. In terms of power performance, IMEP increases with water spraying mass and then decreases, and the maximum value of 6.357 bar is achieved at 25 mg of water spraying mass, which proves that in-cylinder water spraying can effectively suppress the hydrogen-argon oxygen engine knock phenomenon while improving the engine power performance.