Modeling And Application Of Diesel Emission Prediction Based On LabVIEW

With the number of diesel engines keeping increasing and emission regulations more and more rigor, exhaust emissions have constrained diesels' further development because of backward technology, so reducing the diesel emissions has become a severe problem needed to be solved. Before cutting down the emissions, it demands more to know the amount, the law and influence factors for discharge besides knowing the mechanism of emission forming, which could supply theory gist to take emission control actions. As a result, emission prediction has turned into investigative focus.Based on previous researches, quasi-dimension models have been built to predict diesel's carbon monoxide, carbon dioxide, nitric oxide, carbon hydrogen and soot emissions. First, carbon monoxide and carbon dioxide's discharge as well as the equilibrium concentration of nitric oxide have been estimated by using three-zone combustion model. Second nitric oxide has been predicted by using partial equilibrium concentration calculation of Zeldovich mechanism. Next, carbon hydrogen emission prediction model has been built by analyzing its main sources in diesel combustion process. At last, soot discharge has been calculated by adopting semi-empirical two-rate equation proposed by Hiroyasu. In this thesis, measured indicator diagrams have been used as the models' import in order to improving the accuracy of prediction results.The models as stated above have been applied to 6135ZG diesel to predict the amount and the law of discharge for five different emissions under a certain steady operating condition and load operating condition. The absolute percentage errors between calculated results and experimental results are less than 6%. At same time, the change rules of five different emissions in cylinder and under load operating condition have been analyzed. As result of transient operating condition can be regarded as the continuous set of a series of quasi-steady operating condition according to time series. Based on the study of steady emissions prediction, the amount of discharge for five different emissions under constant load acceleration operating condition has been estimated. As there have no experimental data to verify transient prediction results, just prove the reasonability of calculated results indirectly.The study of emission prediction is closely related to combustion research. Traditional instruments have the disadvantages of high investment cost and high maintenance cost, at the same time, they are hard to ensure the synchronous relationship between exhaust discharge and combustion process. So in the end of this paper, that emission prediction modules have been added to the virtual instrument platform of diesel combustion test analysis constructs a new platform which not only could be used to test and analyze combustion process, but also could be used to predict diesel emissions.