Analysis And Research On The Influence Of EGR System And Fuel Injection Parameters On The Performance Of Marine Diesel Engine

Diesel engines have been widely used in ships, machinery and many other areas. The emission of diesel engine has been relatively large. Pollutants floating in the air have been serious threats to our health and social development. Therefore, to improve the emissions of diesel engine has become urgent.Currently, Exhaust gas recirculation technology and EFI technology is an effective means to reduce diesel emissions. In the paper, a simulation model of diesel engine with EGR system was established by using GT-power software. Then diesel engine simulation model was verified by comparing the experimental values and analog values. The EGR rate, EGR cooling temperature, injection pressure and injection advance angle on diesel engine performance are studied by using the simulation model. Its goal is to keep the fuel consumption basically remaining unchanged, as far as possible to reduce NOx, Soot emissions and meet IMO standards in 2016.Get the following conclusion to analyze simulation results:(1) NOx is mainly distributed in both sides of the combustion chamber; Soot is mainly distributed in the center of the combustion chamber.(2) With the only increases of the EGR rate, the maximum value of the cylinder pressure, the cylinder temperature and heat release rate are being reduced. EGR rate increases could effectively reduce NOx emissions. But the EGR rate is too high, Soot emissions and fuel consumption rate will be significantly increased. Considering the diesel emissions, it is determined at 100% load conditions, EGR rate control in 6.0% range was more reasonable. At 75% load conditions, EGR rate control in 8.0% range was more reasonable. At 50% load conditions, EGR rate control in the 12.0% range was more reasonable. At 25% load conditions, EGR rate control in the 18.0% range was more reasonable.(3) With the only increases of EGR cooling temperature, the maximum value of the cylinder pressure and the cylinder temperature increases, the maximum value of heat release rate are being reduced; The appropriate exhaust gas temperature can reduce NOx and Soot emissions while fuel consumption rate is reduced.(4) With the only increases of injection pressure, the maximum value of cylinder pressure, the cylinder temperature and heat release rate increase; The appropriate injection pressure can reduce NOx and Soot emissions while fuel consumption rate is reduced.(5) With the only increases of injection advance angle, the maximum value of the cylinder pressure, the cylinder temperature and heat release rate increase; NOx emission is enlarged and Soot emission reduce;There is an optimal injection advance angle making the lowest fuel consumption rate. At 100% load conditions, injection advance angle in 10.1 ° CA makes the lowest fuel consumption. At 75% load conditions, injection advance angle in 11.1 ° CA makes the lowest fuel consumption. At 50% load conditions, injection advance angle in 12.1 ° CA makes the lowest fuel consumption. At 25% load conditions, injection advance angle in 12.6 ° CA makes the lowest fuel consumption.(6) Considering the economy and emissions of diesel engine, the appropriate EGR rate, EGR cooling temperature, injection pressure and injection advance angle were found in four kinds of operating point. this approach makes fuel consumption rate decrease, while NOx emission rate was also significantly reduced by nearly 60%, reaching IMO Tier ? emission 2016 standards.