Research On The Effect Of Intake Manifold On The Intake Flow Characteristics Of JX493 Diesel Engine

Diesel airway structure is the important factors to determine the in-cylinder air flow and vortex intensity, which directly affect the diesel mixture air formation and combustion, thus affecting power, economy and emissions performance of diesel engines. JX493 series diesel engine has low production cost, good performance, the market outlook, great room for improvement, etc, so it is valuable to study the design of airway so as to further improve the performance.This thesis has done the steady flow test of diesel engine(type: JX493ZLQ4) single helical port, after analysis of test result, it has been found that after install helical port, four cylinder flow coefficient and each cylinder uniformity changes small, but the swirl ratio of four cylinder uniformity became bad, and the swirl ratio of second cylinder was smaller than the others. As the decreasing of the valve stroke, the swirl ratio of four cylinder uniformity became worse, especially the second cylinder and the third cylinder, the swirl ratio of the third cylinder is bigger than the others.For in-depth analysis of the reasons for each cylinder swirl ratio uniformity variation, the author used UG to make 3D solid model for intake manifold-intake, and got geometric model of single helical port with intake manifold. And the STAR-CCM+ software was used to make high quality polyhedral calculation grid computing simulation, compare the simulation results with experimental results, confirming the reliability and validity of simulation calculations.Analyzing of the velocity distribution, flow coefficient and swirl ratio, it is found that there are obvious differences in each cylinder of the entrance inlet flow field distribution. The gas flow rate that flow through the entrance of second cylinder airway near one side of the volute is less than the other cylinders, and at the smaller valve lift, the gas flow rate that flow through the entrance of third cylinder airway near one side of the volute is greater than the other cylinders. The nonuniform in-cylinder swirl ratio mainly due to the nonuniform distribution of flow field in the cross section.The differences of uniformity in-cylinder swirl ratio has indirect effects on the performance of the diesel engine calibration work, it is necessary to improve uniformity of real machine each cylinder swirl ratio. By increasing the intake manifold and regulators over the chamfer cavity, increasing the volume of the cavity of the regulator, adjust the position of the intake manifold to modify the intake manifold, the simulation of the intake improved flow coefficient and swirl ratio, and the original airway simulation results were compared and found that the uniformity of swirl ratio was improved.Through using CFD the configuration parameter and flow behavior was intuitively revealed, and combined with steady flow test, the helical port can be efficiently developed and designed, and the performance of diesel engine will be improved.