Integrated System Modeling Of TY3100 Non-road Diesel Engine

Energy and environmental protection have become two main themes of the contemporary world.As society and economy developing,the problem caused by non-road diesel engine emission has been widely drawing people's attention,and lots of countries have established non-road diesel engine emission regulation.Compared to experiment,integrated system modeling of diesel engine is of great advantage and plays an important role in diesels' design and performance-improvement.Therefore, integrated system of TY3100 non-road diesel engine was modeled in this thesis in order to provide references for performance-improvement.Firstly,integrated system modeling method of TY3100 non-road diesel engine based on GT-Power was discussed in this thesis.The main items include the following:the mathematic models applied to simulation were introduced and appropriate physical models adopted in this thesis were analyzed in details which include combustion models,heat transfer and gas exchange models inside the cylinder,friction loss,pressure loss and heat transfer through pipes and so on.Then the module parameters of the model were discussed at length such as the structural parameters of intake and exhaust system,lift profile and discharge coefficient of valves,the parameters of combustion and heat transfer model,the friction loss etc. The engine performance was simulated and the calculation results agreed well with the experiment data.In order to improve the prediction accuracy,the sensitivities of some parameters were investigated such as intake port's wall temperature,heat transfer coefficient,friction coefficient,pressure loss coefficient and so on.Secondly,the simulations under rated condition and peak torque condition were conducted.The main performances were analyzed which include working-process inside the cylinder and flow characteristic through pipes.The analysis can provide references for the research and improvement of the diesel engine performance.Thirdly,the following aspects were also numerically investigated:(1) The effects of pipe's diameter and length on volumetric efficiency were studied for the intake manifold.In order to improve intake homogeneity,the structure of the intake manifold was redesigned;discharge rate and volumetric efficiency of each cylinder were compared.(2) The effects of pipe's diameter and length on performance (especially the exhaust pressure fluctuation) were studied for the exhaust manifold;in order to improve exhaust performance,exhaust manifolds were designed longer and thicker which can prevent back-flowing from happening in the exhaust process effectively.(3) When compression ratio was studied,how to simulate the influence of compression ratio on diesel's performance was researched;also the impact of injection timing on performance was inspected.(4) When valve timing was studied, the influences of intake valve closing,exhaust valve opening,valve overlapping and valve lash on performance were analyzed.The results indicate that intake valve closing,valve overlapping and valve lash affect volumetric efficiency a lot,while the influence of exhaust valve opening on brake torque as well as the fuel consumption was more obvious.The analysis of the simulation results can provide important theoretic guidance for improvement and optimal designs of TY3100 non-road diesel engine.