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Tuesday, November 2, 2010

LabVIEW different combustion chamber shapes based on natural gas engine emissions prediction

Energy and emission pollution in the 21st century the two major research themes of automobile engine, the world increasingly stringent emissions regulations set to limit the emissions of automobile engines, and actively carry out all aspects of research, to take measures to mitigate energy depletion and environmental degradation problem. Many ignition engine fuel, including gasoline, natural gas, liquefied petroleum gas, natural gas, mixed with hydrogen, in which the carbon content of natural gas with low calorific value higher characteristic, and abundant, easy to store and transport it as a clean fuel, has become a kinds of important engine of energy and is widely used. Most of the studies also had a large number of relevant theoretical and experimental research studies, including work process modeling, chemical kinetics mechanism of combustion, emissions performance and comprehensive performance studies, it is pursuing the emission of the hot spots. Draw on previous results, this paper LabVIEW as software platform, the gas engine as the main object of study, the establishment of a spark ignition engine emissions prediction program, tasks include: (1) the establishment of a quasi-dimensional spark ignition engine emissions forecasting model include: Using dual-zone model to predict CO, CO2, O,, H,, H2O, OH, H, O, NO, NO, this balance of 10 kinds of products of combustion emissions, and in the combustion balance calculation, based on partial equilibrium concentration method using Zeldovich predict NO emissions. (2) is implemented in the LabVIEW program for estimating emissions of spark ignition engines, in order to make the program universal, to adapt to different fuels, different models and different conditions of varying parameters computing needs, the characterization of fuel type, model and condition of the structure parameters and operating parameters and the interface of classification, and natural gas engines and 6135ZG 492Q gasoline engine as an example to illustrate the procedures for different fuels, different models and features variable condition. (3) taking into account the stage of the geometric parameters of the combustion chamber shape differences when calculating the impact, the paper choice of 5 typical ignition engine combustion chamber: gas engine combustion chamber shallow basin-shaped, hemispherical combustion chamber, bowl-shaped combustion chamber, the wedge chamber, bathtub-shaped combustion chamber, this chamber dimensions of 5, based on the integration node, according to their characteristics, determine the appropriate method of combustion geometry (including the node partition method and the integral superposition formulas) and the preparation of the corresponding procedures. (4) 6135ZG natural gas engines for the validation and application examples: First of all rated conditions predicted balance of 10 kinds of products of combustion emissions and emissions of non-equilibrium products of NO to verify the correctness of the program, while analysis of this condition CO, CO2, NO emissions cylinder variation of the three; subsequent prediction of the compression ratio and combustion chamber shape on the 6135ZG gas engine emissions; Finally, choose a same operating point, the value of natural gas engine with the original diesel engine emissions prediction the measured emission values were compared. 

Key words: natural gas engine; compression ratio; chamber shape; emission projections

 

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