The Performance Simulation And Optimization Research On Intake And Exhaust System Of YC6T Diesel Engine

Intake and exhaust system of diesel engine decides the cylinder entering fresh air flux, swirl movement and the usage of exhausting pressure wave. It is one of the most important factors for high quality combustion. The excellent intake and exhaust system can increase volumetric efficiency, power and torque. It can improve combustion quality also and at the same time decrease BSFC and smoke intensity at the certain rotation speed.The research was the intake and exhaust port of YC6T diesel engine. Steady flow test and three-dimensional CFD calculation were used to research the performance of diesel engine ports. Firstly, discharge coefficient and swirl ratio were measured by steady flow tests and Ricardo average discharge coefficient was calculated from tests values. And then the intake and exhaust ports geometric models were gotten by Reverse Engineering. These models were meshed by AVL FIRE FAME. After boundary conditions and turbulence models setting, the air flowing through the intake and exhaust ports were simulated by AVL FIRE software respectively. When the flow progress of air flowing through the intake port was simulated, the different region was set the defferent turbulence modle according to its flowing condition. The compareing between the calculation results and test values showed that the calculation accuracy of multiple turbulence modles setting is higher than single turbulence modle. The maximum relative error between calculations and tests is less than 10 percent. The simulation method can be used to forecast and evaluate the performance of intake and exhaust ports. At last, the partial places of intake and exhaust ports including inlet valves and valve seats were modified based on analyzing flow simulation graphs. Several modified schemes were discussed. The discharge coefficient was increased 12 percent by the last optimization structure of intake port and the swirl ratio was increased too, but the flow resistance was not enlarged. The increased percentage of exhaust port discharge coefficient was 9.68 by optimized scheme. This research has supplied design and optimization reference of intake and exhaust ports for factory.