Optimization Strategy of Exhaust Manifold Based on Numerical Simulation

On the basis of engine bench test,1D engine cycle simulation and 3D computational fluid dynamics(CFD) technology were adopted on a four cylinder diesel engine to investigate the effecting factors resulting in different exhaust gas temperature in each cylinder.The simulated results show that the exhaust temperature difference is caused by combined effects of the working process in each cylinder,the sensor position and exhaust manifold design,among which exhaust manifold design is the most important factor.The closer to the exhaust valve the sensor position is,the more exact the measured value is,which will represent the real thermal loading condition in the cylinder.Based on the simulated results,the original exhaust manifold was optimized.A strategy for exhaust manifold optimization was proposed.