| The quality of Intake system structure is one of the most influential factors on volumetric efficiency, gas exchange and in-cylinder combustion of engine. For this reason, it influences the dynamic property, fuel economy and emission behavior of the engine directly. This thesis mainly discussed the simulation on the airflow characteristics of intake system and the performance of a turbocharged diesel engine, based on the one-dimension flow analysis theory.Firstly, the one-dimension simulation model of the diesel engine was established by GT-Power software. The processes of the establishment and calibration were introduced and the conclusion of calibration was that the simulation results coincided with the experiment results well. On the basis of the model, the airflow characteristics of intake pipes focused on the fluctuation effect was analyzed.Secondly, the airflow characteristics of intake system under declared working condition was studied in detail. The influences of intake structure parameters on the intake flow were analyzed and the parameters contain the air inlet position and angle, the volume of resonant cavity, the length and diameter of manifold. Then, analysed the airflow characteristics under various engine rotate speed and studied the influences of intake system structures on the brake power,brake torque, fuel consumption and volumetric efficiency of the engine.Finally, the effects of intake system on compressor and gas exchange process were studied. Got the results that the intake manifold had significant effect on the pressure fluctuation of compressor, besides, the intercooler had a good performance to stabilize the intake system pressure. The intake manifold had little influence on the gas exchange process through the one-dimension simulation. Further comprehensive researches on the gas exchange process should be started with the combination of intake system, in-cylinder and exhaust system. |
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