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A Control Algorithm for Low Pressure - EGR Systems Using a Smith Predictor with Intake Oxygen Sensor Feedback
ISSN: 0148-7191, e-ISSN: 2688-3627
Published April 05, 2016 by SAE International in United States
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Low-pressure cooled EGR (LP-cEGR) systems can provide significant improvements in spark-ignition engine efficiency and knock resistance. However, open-loop control of these systems is challenging due to low pressure differentials and the presence of pulsating flow at the EGR valve. This research describes a control structure for Low-pressure cooled EGR systems using closed loop feedback control along with internal model control. A Smith Predictor based PID controller is utilized in combination with an intake oxygen sensor for feedback control of EGR fraction. Gas transport delays are considered as dead-time delays and a Smith Predictor is one of the conventional methods to address stability concerns of such systems. However, this approach requires a plant model of the air-path from the EGR valve to the sensor. An open loop EGR mass flow model as well as a simplified plug flow based transport model are utilized to predict EGR fraction at different locations in the air system upstream of the intake oxygen sensor. A turbocharged gasoline spark ignition engine with a low-pressure EGR system is used for algorithm validation. The control algorithm is implemented and tested in real-time using a rapid prototype control system. Experiments consisting of step changes in EGR fraction are performed at steady state engine operating conditions. A clear improvement in control stability and accuracy was observed with the Smith Predictor control over a conventional PID controller.
CitationKoli, R., Siokos, K., Prucka, R., Jade, S. et al., "A Control Algorithm for Low Pressure - EGR Systems Using a Smith Predictor with Intake Oxygen Sensor Feedback," SAE Technical Paper 2016-01-0612, 2016, https://doi.org/10.4271/2016-01-0612.
- Siokos, K., Koli, R., Prucka, R., Schwanke, J. et al., "Assessment of Cooled Low Pressure EGR in a Turbocharged Direct Injection Gasoline Engine," SAE Int. J. Engines 8(4):1535-1543, 2015, doi:10.4271/2015-01-1253.
- Song, D., Jia, N., Guo, X., Ma, X. et al., "Low Pressure Cooled EGR for Improved Fuel Economy on a Turbocharged PFI Gasoline Engine," SAE Technical Paper 2014-01-1240, 2014, doi:10.4271/2014-01-1240.
- Kaiser, M., Krueger, U., Harris, R., and Cruff, L., "“Doing More with Less” - The Fuel Economy Benefits of Cooled EGR on a Direct Injected Spark Ignited Boosted Engine," SAE Technical Paper 2010-01-0589, 2010, doi:10.4271/2010-01-0589.
- Liu, F. and Pfeiffer, J., "Estimation Algorithms for Low Pressure Cooled EGR in Spark-Ignition Engines," SAE Int. J. Engines 8(4):1652-1659, 2015, doi:10.4271/2015-01-1620.
- Takaki, D., Tsuchida, H., Kobara, T., Akagi, M. et al., "Study of an EGR System for Downsizing Turbocharged Gasoline Engine to Improve Fuel Economy," SAE Technical Paper 2014-01-1199, 2014, doi:10.4271/2014-01-1199.
- Hansen, J., Niemann, H., “Exhaust Gas Recirculation Control for Large Diesel Engines - Achievable Performance with SISO Design,” IFAC 9th Conference on Control Applications in Marine Systems, ISSN - 14746670.
- Hegarty, K., Dickinson, P., Cieslar, D., and Collings, N., "Fast O2 Measurement using Modified UEGO Sensors in the Intake and Exhaust of a Diesel Engine," SAE Technical Paper 2013-01-1051, 2013, doi:10.4271/2013-01-1051.
- Welling, O. and Collings, N., "UEGO Based Measurement of EGR Rate and Residual Gas Fraction," SAE Technical Paper 2011-01-1289, 2011, doi:10.4271/2011-01-1289.
- Guzzela, L. and Onder, C., “Introduction to Modeling and Control of Internal Combustion Engine Systems” Springer publications
- Normey-Rico, J., “Control of Dead-time Processes,” Springer publications
- Heywood, J., “Internal Combustion Engine Fundamentals,” McGraw-Hill publications
- Nishio, Y., Hasegawa, M., Tsutsumi, K., Goto, J. et al., "Model Based Control for Dual EGR System with Intake Throttlein New Generation 1.6L Diesel Engine," SAE Technical Paper 2013-24-0133, 2013, doi:10.4271/2013-24-0133.
- Fu, J. and Kurihara, N., "Intake Air Control of SI Engine Using Dead-Time Compensation," SAE Technical Paper 2003-01-3267, 2003, doi:10.4271/2003-01-3267.
- Siokos, K., Koli, R., Prucka, R., Schwanke, J. et al., "Physics-Based Exhaust Pressure and Temperature Estimation for Low Pressure EGR Control in Turbocharged Gasoline Engines," SAE Technical Paper 2016-01-0575, 2016, doi:10.4271/2016-01-0575.