Open AccessLinear dynamic parameter‐varying sliding manifold for air–fuel ratio control in lean‐burn engines
Author(s) -
Tafreshi Reza,
Ebrahimi Behrouz,
Mohammadpour Javad,
Franchek Matthew A.,
Grigoriadis Karolos,
Masudi Houshang
Publication year - 2013
Publication title -
iet control theory and applications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.059
H-Index - 108
eISSN - 1751-8652
pISSN - 1751-8644
DOI - 10.1049/iet-cta.2012.0823
Subject(s) - control theory (sociology) , inlet manifold , robustness (evolution) , ignition system , lean burn , air–fuel ratio , system dynamics , perturbation (astronomy) , sliding mode control , engineering , computer science , nonlinear system , automotive engineering , internal combustion engine , control (management) , combustion , physics , biochemistry , chemistry , organic chemistry , quantum mechanics , artificial intelligence , aerospace engineering , gene , nox
Precise control of air–fuel ratio (AFR) is one of the most challenging tasks in lean‐burn spark ignition engines control. The main problem arises because of the large time‐varying delay in the engine operating envelope. In this study, a new sliding mode‐based synthesis method is presented to control AFR in order to improve fuel economy and decrease the tailpipe emissions. The time‐varying delay dynamics is first estimated by Padé approximation, which transfers the system into a system with parameter‐varying non‐minimum phase dynamics. Non‐minimum phase characteristics restrict the application of conventional sliding mode control approach because of the unstable internal dynamics. The system dynamics is then rendered into the normal form to investigate the system unstable internal dynamics. A systematic approach is proposed to design a linear dynamic parameter‐varying sliding manifold (LDPVSM) in order to stabilise the unstable internal dynamics according to the desired output tracking error dynamics. Additionally, the proposed LDPVSM provides the system with robustness against unmatched perturbation. The method that can be easily implemented in practical settings exhibits the desired dynamics independent of the matched and unmatched disturbances. The results of applying the proposed method to experimental data demonstrate the closed‐loop system stability and a superior performance against time‐varying delay, canister purge disturbances and measurement noise.