Abstract
Cycle-to-cycle feedback control is employed to achieve optimal combustion phasing while maintaining high levels of exhaust gas recirculation by adjusting the spark advance and the exhaust gas recirculation valve position. The control development is based on a control-oriented model that captures the effects of throttle position, exhaust gas recirculation valve position, and spark timing on the combustion phasing. Under the assumption that in-cylinder pressure information is available, an adaptive extended Kalman filter approach is used to estimate the exhaust gas recirculation rate into the intake manifold based on combustion phasing measurements. The estimation algorithm is adaptive since the cycle-to-cycle combustion variability (output covariance) is not known a priori and changes with operating conditions. A linear quadratic regulator controller is designed to maintain optimal combustion phasing while maximizing exhaust gas recirculation levels during load transients coming from throttle tip-in and tip-out commands from the driver. During throttle tip-outs, however, a combination of a high exhaust gas recirculation rate and an overly advanced spark, product of the dynamic response of the system, generates a sequence of misfire events. In this work, an explicit reference governor is used as an add-on scheme to the closed-loop system in order to avoid the violation of the misfire limit. The reference governor is enhanced with model-free learning which enables it to avoid misfires after a learning phase. Experimental results are reported which illustrate the potential of the proposed control strategy for achieving an optimal combustion process during highly diluted conditions for improving fuel efficiency.
Original language | English |
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Pages (from-to) | 1819-1834 |
Number of pages | 16 |
Journal | International Journal of Engine Research |
Volume | 21 |
Issue number | 10 |
DOIs | |
State | Published - Dec 1 2020 |
Funding
The authors thank Charles Solbrig from the University of Michigan for the technical support during experiments. The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: The work presented was funded, in part, by the Advanced Research Projects Agency-Energy (ARPA-E), US Department of Energy, under award number DE-AR0000659, for which we are thankful. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. This research was also supported by the DOE Office of Energy Efficiency and Renewable Energy (EERE), Vehicle Technologies Office, under the guidance of Gurpreet Singh and Michael Weismiller, and used resources at the National Transportation Research Center, a DOE-EERE User Facility at Oak Ridge National Laboratory. The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: The work presented was funded, in part, by the Advanced Research Projects Agency-Energy (ARPA-E), US Department of Energy, under award number DE-AR0000659, for which we are thankful. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. This research was also supported by the DOE Office of Energy Efficiency and Renewable Energy (EERE), Vehicle Technologies Office, under the guidance of Gurpreet Singh and Michael Weismiller, and used resources at the National Transportation Research Center, a DOE-EERE User Facility at Oak Ridge National Laboratory.
Keywords
- Combustion control
- cycle-to-cycle combustion variability
- exhaust gas recirculation
- learning reference governor
- linear quadratic Gaussian
- misfire
- spark-ignition engines