Abstract
Higher fuel economy and lower exhaust emissions for spark-ignition engines depend significantly on precise air-fuel ratio (AFR) control. However, the presence of large time-varying delay due to the additional modules integrated with the catalyst in the lean-burn engines is the primary limiting factor in the control of AFR. In this paper, the engine dynamics are rendered into a nonminimum phase system using Padé approximation. A novel systematic approach is presented to design a parameter-varying dynamic sliding manifold to compensate for the instability of the internal dynamics while achieving desired output tracking performance. A second-order sliding mode strategy is developed to control the AFR to remove the effects of time-varying delay, canister purge disturbance, and measurement noise. The chattering-free response of the proposed controller is compared with conventional dynamic sliding mode control. The results of applying the proposed method to the experimental data demonstrate improved closed-loop system responses for various operating conditions.
Original language | English (US) |
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Article number | 6612669 |
Pages (from-to) | 1374-1384 |
Number of pages | 11 |
Journal | IEEE Transactions on Control Systems Technology |
Volume | 22 |
Issue number | 4 |
DOIs | |
State | Published - Jul 2014 |
Keywords
- Air-fuel ratio (AFR) control
- dynamic sliding manifold
- lean-burn engine
- nonminimum phase system
- second-order sliding mode
- time-varying delay
ASJC Scopus subject areas
- Control and Systems Engineering
- Electrical and Electronic Engineering