The Study Of The Exhaust System Which Is Attached To Sequential Turbocharged Vehicle Diesel

This paper makes a research on the sequential turbocharging system of diesel engine. Taking the type YC6J-270 straight six cylinders turbocharged diesel engine as study object, the paper makes a design and calculation for its sequential turbocharging system so that the system and the diesel engine can form a good match to reach the prospective requirement of technical performance.The study is based on the way of CAD to design the turbocharging system. The design scheme is to install an impulse transferor and the parallel bifurcated pipe behind the exhaust pipe of the original three pulse pressure charging system and adjust them to the pipeline layout. At the same time, exhaust valves is installed before the turbines to keep the turbochargers in a right working order.The design contents include the impulse transferor, the exhaust valve, the related parallel pipeline and the whole layout design of the sequential turbocharging system. UG is used in the components design, GT-power is used in the calculation of one dimensional match between supercharging system and diesel engine, Fluent is used in the calculation of stable and unstable flow field and the simulation module of UG is used for the valve strength calculation.The results of the simulation show that the designed turbocharging system matches well with the diesel engine with higher power and lower specific fuel consumption, at the same time, it provides the boundary conditions for three dimensional flow filed. The calculation of the unstable three dimensional flow field can simulate more real the changing situation of the transient flow field when exhaust pulse exchange energy and the calculation result shows that the impulse transferor woks well enough to be used in the sequential turbocharging system. Oblique-plate flap valve with reliable strength and smooth flow proved by simulating calculation is used for exhaust valve.At the same time, the paper proposes to adopt MPC exhaust pipe in the sequential turbocharging system and carries out the parameter design and the simulating calculation on the flow filed of the MPC exhaust pipe.