The Simulation Research Of The Inboard Purification Technology For Diesel Engine

Due to its good economy and power performance, the diesel engine has been widely used around the world. However, as the quantity of diesel-powered transport vehicles keeps increasing, the harm caused by Auto emissions on the environment and human health catches more and more attention. Compared with gasoline engine, diesel engine’s main emissions are NOx and SOOT. NOx causes lots of environmental problems, such as acid rain, photochemical smog, the hole in the ozone layer etc. And SOOT is an important part of PM2.5in atmospheric environment. So the Diesel emissions control technologies have become a key issue, which may restrict its future development. To solve this problem, the main measures taken by current people are the combination of inboard purification and exhaust aftertreatment. The purpose of the inboard purification technology is:in the condition of maintaining the diesel engine’s good power and economic performance as much as possible, controlling the original engine’s NOx&SOOT emissions, and then reducing the after-treatment device’s "burden".In this paper, applying AVL/BOOST&FIRE software platform and bench test data, the three-dimensional simulation of an8.9L diesel engine is studied. On the basis of the analysis towards original machine’s working process, such as gas exchange, fuel injection and combustion etc., the meanings of late intake valve closing, injection timing, exhaust gas recirculation technologies are studied. The technologies play an important role in promoting gas mixture, improving cylinder combustion and reducing diesel emissions. The contents of this paper:(1) It has created the original engine’s full model, which includes intake port, cylinder, exhaust port, and validated the model at the reference of test data.(2) It has designed a scheme of increasing the inlet valve close angel, based on the original valve timing, and then analyzed the variation trend of diesel engine’s actual compression ratio, air inflow, output power and the emission with the increase of LIVC. In the end, the significance of improving the inlet pressure to optimize diesel engine emissions performance has been studied.(3) It has analyzed the influence law of Fuel injection advance Angle on diesel engine NOx and SOOT’ emission. Simultaneously, for the purpose of reducing the original machine NOx, SOOT emissions, two strategies have been put forward, which are12℃A fuel injection advancing angel+EGR(10%), and4℃A fuel injection advancing angel+post injection. Furthermore the impact of these two strategies on diesel engine’s emission and economy performance has been studied.