Design And Experimental Analysis Of The Transient Experiment Device For Vehicle Turbocharger

In order to improve the performance of turbocharger,improve the matching between the engine and turbocharger and optimize the engine,it needs to know about the characteristics of turbocharger deeply.At present,the research focused on steady-state characteristics.The exhaust of the engine is pulsed and the characteristics of the turbocharger in the actual work are instantaneous,so it is very important to study the transient characteristics of the turbocharger.The transient characteristics of the turbocharger can be used to simulate the transient characteristics of the turbocharger by directly connecting the turbocharger to the engine exhaust pipe or by simulating the engine exhaust waveform through the transient performance test device.The second method not only simplifies the trial,but also reduces the cost of the trial.In this paper,the transient performance of the turbine is simulated by the transient performance test device,and the transient characteristics of the turbine under pulsed inlet condition are studied.The difference between the transient parameters and the steady-state parameters of the turbine and the influence of each factor on the turbine characteristics are analyzed.It provides some references for the design of turbo and the matching of turbocharger and engine.First,the structural design of the transient performance experimental device was completed.On the basis of summarizing the traditional device structure design,a new "gear rotor" structure design scheme was put forward,the whole structure design of the device was completed,the three-dimensional model of the device was built,the two-dimensional drawing was drawn and the trial and manufacture of the device are completed.The newly designed gear rotor transient performance test device can not only meet the requirements of the sudden increase of the initial pressure of the engine exhaust,but also can precisely control the angle between the two channels to achieve different phase intake.In order to verify the rationality of the designed transient performance experimental device,the outlet pressure waveform of the device was simulated from the simulation point based on Fluent and GT-power software.The simulation results show that the transient performance of the device can meet the requirements of the transient characteristics of the turbocharger.The transient performance test device was installed on the performance test bench of the turbocharger.The HE351W turbocharger was tested in the combination of the different values of frequency,expansion ratio and exhaust gas bypass valve opening.The results show that the transient characteristic curve surrounds the steady-state characteristic curve as ring.There is a big deviation between the both,the deviation is mainly caused the volume effect in turbine,meanwhile,the test results proves that using "quasi-steady state" hypothesis in the calculation is deficient.In the experiment at different value of pulse frequency,with the rise of the frequency,the amplitude of the flow rate decline increases,but the amplitude of the efficiency decline decreases;In the different bypass valve opening test,as the valve opening increases,the amplitude of flow rate rise increases,however,the amplitude of efficiency decline increases.Based on the transient performance test of supercharger gantry,the transient characteristics of turbine can be obtained.It can provide guidance and reference for turbine design,calculation and turbocharger and engine matching research.