Diesel engines have proven over the years important in terms of efficiency and fuel consumption to power generation ratio. Many research works show the potential of biodiesel as a substitute for conventional gasoil. M...Diesel engines have proven over the years important in terms of efficiency and fuel consumption to power generation ratio. Many research works show the potential of biodiesel as a substitute for conventional gasoil. Mainly, previous and recent researches have focused on experimental investigation of diesel engine performance fuelled by biodiesel. Researches on the mathematical description of diesel engine process running on biodiesel are scarce, and mostly about chemical and thermodynamic description of the combustion process of biodiesel rather than performance studies. This work describes a numerical investigation on the performance analysis of a diesel engine fuelled by palm oil biodiesel. The numerical investigation was made using a semi empirical 0D model based on Wiebe’s and Watson’s model which was implemented via the open access numerical calculation software Scilab. The model was validated first by comparing with experimental pressure and performance data of a one cylinder engine at rated speed and secondly by comparing with a six cylinders engine performance data at various crankshaft rotational speeds. Simulations were then made to analyze the engine performance when running on biodiesel. The calculations were made at constant combustion duration and constant coefficient of excess air. Results showed that the model matches the overall experimental data, such as the power output and peak cylinder pressure. The ignition delay was somehow underestimated by the model for the first experiment, which caused a slight gap on in cylinder pressure curve, whereas it predicted the average ignition delay fairly well for the second set of validation. The simulations of engine performance when running on biodiesel confirmed results obtained in previous experimental researches on biodiesel. The model will be further investigated for engine control when shifting to biodiesel fuel.展开更多
The development of a diesel engine model using one-dimensional （1-D） fluid-dynamic engine simulation codes,and its validation using experimental measurements are described in this paper.The model was calibrated by r...The development of a diesel engine model using one-dimensional （1-D） fluid-dynamic engine simulation codes,and its validation using experimental measurements are described in this paper.The model was calibrated by running the engine on an electric dynamometer at eight steady-state operating conditions.The refined engine model was used to predict the oxides of nitrogen （NOx） less than those measured earlier in the experiments,and hence to recommend changes in the engine for the verification of the results.The refined engine model is greatly influenced by the start of injection angle （ψ）,ignition delay （φ）,premix duration （DP）,and main duration （DM） for the prediction of reduced NOx emissions.It is found that optimum ψ is 6.5° before top dead center （BTDC）.At this angle,the predicted and experimental results are in good agreement,showing only a difference of up to 4%,6.2%,and 7.5% for engine performance,maximum combustion pressure （Pmax）,and NOx,respectively.展开更多
文摘Diesel engines have proven over the years important in terms of efficiency and fuel consumption to power generation ratio. Many research works show the potential of biodiesel as a substitute for conventional gasoil. Mainly, previous and recent researches have focused on experimental investigation of diesel engine performance fuelled by biodiesel. Researches on the mathematical description of diesel engine process running on biodiesel are scarce, and mostly about chemical and thermodynamic description of the combustion process of biodiesel rather than performance studies. This work describes a numerical investigation on the performance analysis of a diesel engine fuelled by palm oil biodiesel. The numerical investigation was made using a semi empirical 0D model based on Wiebe’s and Watson’s model which was implemented via the open access numerical calculation software Scilab. The model was validated first by comparing with experimental pressure and performance data of a one cylinder engine at rated speed and secondly by comparing with a six cylinders engine performance data at various crankshaft rotational speeds. Simulations were then made to analyze the engine performance when running on biodiesel. The calculations were made at constant combustion duration and constant coefficient of excess air. Results showed that the model matches the overall experimental data, such as the power output and peak cylinder pressure. The ignition delay was somehow underestimated by the model for the first experiment, which caused a slight gap on in cylinder pressure curve, whereas it predicted the average ignition delay fairly well for the second set of validation. The simulations of engine performance when running on biodiesel confirmed results obtained in previous experimental researches on biodiesel. The model will be further investigated for engine control when shifting to biodiesel fuel.
基金Sponsored by the National Natural Science Foundation of China (50576063)
文摘The development of a diesel engine model using one-dimensional （1-D） fluid-dynamic engine simulation codes,and its validation using experimental measurements are described in this paper.The model was calibrated by running the engine on an electric dynamometer at eight steady-state operating conditions.The refined engine model was used to predict the oxides of nitrogen （NOx） less than those measured earlier in the experiments,and hence to recommend changes in the engine for the verification of the results.The refined engine model is greatly influenced by the start of injection angle （ψ）,ignition delay （φ）,premix duration （DP）,and main duration （DM） for the prediction of reduced NOx emissions.It is found that optimum ψ is 6.5° before top dead center （BTDC）.At this angle,the predicted and experimental results are in good agreement,showing only a difference of up to 4%,6.2%,and 7.5% for engine performance,maximum combustion pressure （Pmax）,and NOx,respectively.
