Influence of Helical Intake Port Structure Parameters of Diesel Engine on Intake Performance

To enhance the performance of the diesel engine helical intake port, computational fluid dynamics (CFD) was employed to conduct numerical simulations of the intake port and in-cylinder flow of the D19 diesel engine. The primary focus of the study was to investigate the effect of structural design parameters of the diesel engine helical intake port on the cylinder swirl ratio and intake mass. By modifying the three main structural design parameters of the helical intake port, we explored their effect on the in-cylinder swirl ratio. The study utilized deflection angle (θ), helical chamber height (H), and eccentric distance (Δa) as three influential factors, each set at three levels. Orthogonal experiments and linear regression analysis were conducted using swirl ratio and intake mass as evaluation indicators for the airflow characteristics in the intake port. The results show that the influence weights of the intake port structural parameters on swirl ratio and intake mass are as follows: H > Δa > θ, and H > θ > Δa. When the three key structural parameters of θ, H, and Δa are changed individually so that their values are −15 deg, 6.28 mm, and 3 mm, respectively, the in-cylinder swirl ratio obtains the maximum value and satisfies the linear regression equation, y = 0.754–0.005θ + 0.165H + 0.088Δa. From the analysis of the results of the F test, it can be found that the significant p value is 0.362, which is not statistically significant. There is no linear regression relationship between the intake mass and the θ, H, and Δa.