To study the effects of the design parameters of a helical intake port on the in-cylinder swirl ratio for an automotive diesel engine, the transit port and in-cylinder flows were simulated with the Converge CFD software. By changing the values of three main design parameters of the intake port, their effects on the in-cylinder swirl ratio were simulated and studied. The results have shown that the in-cylinder swirl ratio achieved the maximum values when the spiral chamber height, the vortex shell cut-off amount and the helical intake port angle were changed to the values of 13 mm, 1.27 mm and 0 degree, respectively. The results also indicated that the effects of the parameters on the swirl ratio were not additive when multiple parameters were varied at the same time. This study has shown that the numerical analysis of multiple design parameters of a helical intake port can be done with the use of the Converge software.