Cycle Simulation Study On TY3100CR High-Pressure Common Rail Diesel Engine

The widely used non-road machinery, with poor working conditions and severe environmental problems, has aroused worldwide concern. And emission regulations for the non-road diesel engines have been established to control the harmful pollutants. Matching of fuel system with intake system and combustion chamber is one of the most important factors for improving diesel emission. The current TY3100EZ diesel engine, designed for the2008emission regulation, fail to meet the EPA Tier4B standards which will be implemented in2013. Therefore, the performance of emission and power need to be improved for further usage. The TY3100CR diesel engine, an improved model is discussed in this thesis and research work is on the high pressure common-rail fuel system and EGR system.Firstly, simulation model of the high pressure common-rail system, which include the common rail pipe and the electronic control injector model is built by GT-Fuel software. The focus of the high-pressure common rail diesel engine is the pressure oscillation in common rail pipe and the injection rate. Effects of the common rail pipe volume, length, diameter on the pressure oscillation and fuel supply uniformity in the rail is studied, and influence of injector assembly parameters (mainly include the number of nozzle holes, the aperture, control volume, the diameter of oil inlet and return hole, the needle mass and the spring preload force) on injection characteristics is also discussed..Secondly, complete model of TY3100CR engine was established by using the software of GT-Power and GT-Fuel. Optimization of the valve timing and cam profile is conducted by the DOE module and the VT-Design software. Then the engine performance is predicted with optimized compression ratio and injection timing. Results show that the effect of injection timing optimization only on NOx reduction is limited, thus a combination of other skills is needed. In addition, the improved engine can meet the power and economy requirements, but the NOx and SOOT emissions is still too high.Finally, the simulation model of EGR system was established by GT-Power to study the effect of EGR technology on the performance of diesel engine. The results show that: EGR system can reduce the NOx emissions greatly, but may increase the smoke emissions; and the inter-cooled EGR technology can improve the engine performance better, especially for the SOOT and the fuel consumption rate. At last, simultaneous DOE optimization of EGR rate and Injection Timing Angle is carried out to improve the engine performance, the optimize results are as following: for the maximum torque conditions, SOI=-4.3℃A, EGR rate=12.7%; for the rated conditions: SOI=-7.9℃A, EGR rate=13.5%. In this case, the power, economy and NOx emissions performance of diesel engine can meet the designed requirements.