EGO sensor based robust output control of EGR in diesel engines

In diesel engines, exhaust gas recirculation (EGR) is an efficient method for reducing NO/sub x/. EGR rates are commonly set according to the expected engine behavior, without considering the actual composition of the exhaust gases. In this paper, a new control system for EGR in passenger cars is presented, based on an exhaust gas oxygen (EGO) sensor as indicator of the combustion state as well as on a robust design approach to cope with the parameter variations. The proposed control has been designed for and tested on an Audi TDI engine and has been found to yield a similar performance as the conventional controllers for the standard engine, in spite of the transport delays between combustion process and measurement. Due to the presence of feedback, reduced sensitivity and/or detectability of wear, production irregularities, changes of operating conditions and calibration faults are expected from long-time measurements. >

[1]  Tessho Yamada,et al.  Universal Air-Fuel Ratio Heated Exhaust Gas Oxygen Sensor and Further Applications , 1992 .

[2]  Paul Zelenka,et al.  NOx Reduction Strategies for DI Diesel Engines , 1992 .

[3]  Alois Amstutz,et al.  Structured Black Box Model and Robust Control of the Exhaust Gas Recirculation of a Diesel Engine , 1993 .

[4]  John J. Moskwa,et al.  Turbocharged Diesel Engine Modeling for Nonlinear Engine Control and State Estimation , 1995 .

[5]  Joachim Schommers,et al.  Exhaust-Emission Optimization of DI-Diesel Passenger Car Engine with High-Pressure Fuel Injection and EGR , 1993 .

[6]  Lennart Ljung Identifying State-space Models with Mathwork’s System Identification Toolbox , 1991 .

[7]  Ben M. Chen,et al.  A New Stable Compensator Design for Exact and Approximate Loop Transfer Recovery , 1990, 1990 American Control Conference.

[8]  K. P. Dudek,et al.  A control-oriented model for cylinder pressure in internal combustion engines , 1989 .

[9]  H. Endres,et al.  Exhaust-Gas Recirculation - A Measure to Reduce Exhaust Emissions of DI Diesel Engines , 1992 .

[10]  G. Stein,et al.  Robustness with observers , 1978, 1978 IEEE Conference on Decision and Control including the 17th Symposium on Adaptive Processes.

[11]  M. Athans,et al.  Robustness results in linear-quadratic Gaussian based multivariable control designs , 1981 .

[12]  G. Stein,et al.  The LQG/LTR procedure for multivariable feedback control design , 1987 .

[13]  Rainer Noack,et al.  Heated Zirconia Oxygen Sensor for Stoichiometric and Lean Air-Fuel Ratios , 1984 .