In this study, emissions of compression ignition engine fueled by diesel fuel with nanoparticle additives was modeled by regression analysis, artificial neural network (ANN) and adaptive neuro fuzzy inference system (ANFIS) methods. Cetane number (CN) and engine speed (rpm) were selected as input parameters for estimation of carbon monoxide (CO), oxides of nitrogen (NOx), and carbon dioxide (CO 2 ) emissions. The results of estimation techniques were compared with each other and they showed that regression analysis was not accurate enough for prediction. On the other hand, ANN and ANFIS modelling techniques gave more accurate results with respect to regression analysis; linear and non-linear. Especially ANFIS models can be suggested as estimation method with minimum error compared to experimental results.
Keywords:Adaptive neuro fuzzy inference system; Artificial neural network; Diesel engine; Regression analysis
INTRODUCTIONIn recent years, depletion of fossil fuels forces researchers to search new alternative fuels. In literature, there are a lot of studies about fuels which have potential to replace fossil fuels used in internal combustion engines. In this respect, various biofuels and alcohols seem as good option [1]. In addition to scarcity of conventional fuels, efforts on performance en-hancement and emission reduction of engines are the other important issues on which engineers and engine manufacturers are working on it. Especially, the stringent emission legislations enforced manufacturers to develop new technologies [2]. Traditional engine research and development studies are both difficult and costly to meet emission limits imposed by legislations. Therefore, these costly studies are replaced by various cost-effective approaches as artificial neural networks (ANN) and computational fluid dynamics (CFD) [3]. ANNs are nonlinear computer algorithms, which can model the behavior of complex nonlinear processes. Recently, this method has been widely applied to various disciplines as automotive engineering [4]. Yusaf et al. studied the effect of using CPO (crude palm oil) -OD (ordinary diesel) blends as fuel on the performance of CI (compression ignition) engine. In addition, engine power output, fuel consumption, and exhaust-gas emission are evaluated and then predicted using ANN technique [5]. Shanmugam et al. used ANN modeling to predict the performance and exhaust emissions of the diesel engine using hybrid fuel and they revealed that the ANN approach could be confidently used to predict the performance and emissions of the diesel engine accurately [6]. Ghazikhani and Mirzaii predicted soot emission of a waste-gated turbo-charged DI diesel engine using ANN. The results showed the ANN approach can be used to accurately predict soot emis-sion of a turbo-charged diesel engine in different opening ranges of waste-gate (ORWG) [7].