Modeling and control of advanced internal combustion engines and urea SCR systems
| Autor: | Chih-cheng Chou, 周志正 |
|---|---|
| Rok vydání: | 2014 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 102 This thesis presents the modeling and control of homogeneous charge compression ignition (HCCI) engines, common rail (CR) diesel Engines and selective catalytic reduction (SCR) systems. First of all, for stability of HCCI engines, A model reference adaptive controller (MRAC) is designed based on a simplified bilinear parametric model to regulate the combustion timing CA50 in the presence of uncertainty or unknown variation in plant parameters such as cylinder charge properties. The adaptive controller is developed based on a simplified control-oriented HCCI cycle-to-cycle ignition timing dynamics model. The simulation results show that the controller is able to regulate the combustion timing CA50 to desired set-point via controlling the rebreathing lift of exhaust valve when a cylinder charge properties are changing with time. Secondly, an engine management system (EMS) is developed for a common-rail diesel engine to achieve precise and flexible control of the rail pressure, fuel injection timing and injected fuel amount. Real-time calculation of the combustion heat release rate (HRR) is conducted based on the cylinder pressure measurement to examine the effect of various fuel types and injection parameters on engine brake power and NOx emission. To reduce the tail-pipe NOx emission of diesel engine, a controller for selective catalytic reduction (SCR) system is developed. Experimental tests in European Stationary Cycle (ESC) and European Transient Cycle (ETC) driving modes are conducted to demonstrate the performance and reliability of the SCR system with a rule-based feedforward plus PI feedback controller. A SCR model is then developed and is validated against experimental data. Finally, an effective method that identifies the cross-sensitivity of SNS to ammonia is proposed on the basis of a periodic modulation of the urea dosage rate and Fast Fourier Transform (FFT) of the SNS signal. This method enables us to measure the true NOx concentration correctly even if the NOx is overkilled by excessive ammonia. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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