Validation of an Emission Model for a Marine Diesel Engine with Data from Sea Operations

In this study,a model is developed to simulate the dynamics of an internal combustion engine,and it is calibrated and validated against reliable experimental data,making it a tool that can effectively be adopted to conduct emission predictions.In this work,the Ricardo WAVE software is applied to the simulation of a particular marine diesel engine,a four-stroke engine used in the maritime field.Results from the bench tests are used for the calibration of the model.Finally,the calibration of the model and its validation with full-scale data measured at sea are presented.The prediction includes not only the classic engine operating parameters for a comparison with surveys but also an estimate of nitrogen oxide emissions,which are compared with similar results obtained with emission factors.The calibration of the model made it possible to obtain an overlap between the simulation results and real data with an average error of approximately 7%on power,torque,and consumption.The model provides encouraging results,suggesting further applications,such as in the study on transient conditions,coupling of the engine model with the ship model for a complete simulation of the operating conditions,and optimization studies on consumption and emissions.The availability of the emission data during the sea trial and validated simulation results are the strengths and novelties of this work.

Hardware-in-the-Loop Research on the Electronic Control Unit for Diesel Engines

A hardware-in-the-loop simulating platform is developed to avoid designing defects caused by the complicated logical structure and multiple-functional buildup of the dectronic control unit（ECU）in modem diesel engines, and to diminish potential damages on components or human exposure to dangers in R＆D en- deavor. This plat-form consists of a computer installed with software Matlab/Simulink/RTW and dSPACE/ ControlDesk; a diesel engine ECU, and a dSPACE autobox which runs a real-time diesel engine model. A typical model of diesel engine with turbocharger and intercooler is presented. Based on this model our research is carried out with a real ECU to test its software control strategies. Results show that by using the diesel engine model downloaded inside, the hardware-in-the-loop platform can simulate diesel engine＇s working conditions and generate all kinds of sensor signals which ECU needs on a real-time basis. So the ECU control strategies can be validated and relevant parameters roughly calibrated.

Computational investigation of the effect of biodiesel fuel properties on diesel engine NOx emissions

A detailed numerical spray atomization,ignition,combustion and nitrogen oxides(NOx)formation model was developed for direct injection diesel engines by using KIVA3V code.Several modified or recalibrated sub-models including a Kelvin-Helmholtz Rayleigh-Taylor(KH-RT)spray breakup model,a Shell ignition model,a single-step kinetic combustion model and a Zel’dovich NOx formation model were incorporated into KIVA3V.This modified model was validated by experimental data obtained from a John Deere 4045T direct injection diesel engine that was fueled with a natural soybean methyl ester,a yellow grease methyl ester,a genetically modified soybean methyl ester and No.2 diesel fuel.Errors between predictions of the brake-specific NOx and measured values were less than 1%at full load.For biodiesel fuels,either the Zel’dovich mechanism overpredicted NOx emissions,the ratio of NO to NOx should be less than diesel fuel,or both.As observed from the modeling results,the higher latent heat of vaporization and higher surface tension of biodiesel relative to diesel fuel did not result in increased NOx emissions.The higher viscosity of biodiesel could be one of the reasons for increased NOx,but its effect was relatively small compared with the effect of decreased spray cone angle and advanced start of injection timing on NOx.Decreased spray cone angle and advanced start of injection were the main reasons for increased NOx emissions of biodiesel.