Experimental And Cycle Simulation Study On TY3100EZ Turbocharged Diesel Engine

With the development of the world economy, people's sense for environmental protection is improving dramatically. Due to the further promotion of non-road machinery, such problems as diesel engine emissions in this regard are increasingly focusing eyeballs of the people worldwide. The international community and its relevant organizations have formulated emission regulations for the non-road diesel engine to reduce the bad effect caused by harmful emissions on human beings and natural environment. For small and medium-sized non-road diesel engine, the optimal match based on fuel supply, intake and combustion chamber is an important approach to reduce harmful emissions. This thesis sampled with TY3100EZ, a non-road turbocharged diesel engine, and researched the paths to control emissions of the non-road diesel to meet the standard of U.S. Environmental Protection Administration Tier4 (EPA Tier4) via experiments. Simulated engine's performance and predicted emissions used GT-Power software.Firstly, emission control experiments were carried out on TY3100EZ turbocharged diesel engine. By testing its performance and emission, the emissions characteristics were analyzed and the final technical solutions were obtained to meet the standard of EPA Tier4. The measurements included adjusting such fueling system parameters as the fuel supply advance angle, pressure reducing volume of the valve, high pressure pipeline diameter, and applying technical measures such as re-designing combustion chamber.Secondly, mathematical physics model of cycle simulation of the diesel engine were introduced, especially the model of its combustion simulation, formation mechanism of NOx and Soot emissions and their reverent models. Based on quasi-dimensional combustion model, extended Zeldovich NOx formation mechanism and Nagle & Strickland-Constable Soot formation model, the system simulation model of TY3100EZ turbocharged diesel engine that can predict NOx and Soot emissions was built with GT-Power software. With the model that created, we also simulated the external characteristics of diesel engine and predicted NOx and Soot emissions under several conditions. The conclusions suggest that results from simulation conform well to that from experimental process.Concurrently, this thesis emphasizes the influence of swirl coefficiency on engine performances during the period of creating models. When considering this coefficiency under the same condition, there is a little change volume for the correlative indexes of engine power and economy, but for the prediction for emissions (NOx and Soot), great effects have shown with dramatic decreasing volume.Then, by adopting simulation models that have created, we studied the influences eminating from the changes of compression ratio, injection advanced timing and supercharging level on diesel engine's performances and emission characteristics of NOx and Soot. The results suggest that, when the fuel injection value of the cycle remains constant, changes of compression ratio has great impact on emissions' generation, and so does injection timing. However, the impact caused by pressurized degree is not a monotonic one, it will show little changes if pressurized degree increased continuously when actually has reached at a dead level.