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Nonlinear Observer-Based Air-Fuel Ratio Control for Port Fuel Injected Wankel Engines

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Original languageEnglish
Title of host publication2018 UKACC 12th International Conference on Control (CONTROL 2018)
Subtitle of host publicationProceedings of a meeting held 5-7 September 2018, Sheffield, United Kingdom
Publisher or commissioning bodyInstitute of Electrical and Electronics Engineers (IEEE)
Number of pages6
ISBN (Electronic)9781538628645
ISBN (Print)9781509064113
DateAccepted/In press - 15 Jun 2018
DateE-pub ahead of print - 1 Nov 2018
DatePublished (current) - Dec 2018


The use of Wankel engines has been severely limited as the emission regulations get stringent around the world since the 1970s. The fuel puddles due to port fuel injection (PFI) and the leakage between combustion chambers are significant sources of efficiency loss and emissions. For most spark ignition engines in production, the emission strongly depends on the air-fuel ratio (AFR) controller in cooperation with a three-way catalytic (TWC) converter. This paper presents a generic observer-based AFR control framework to deal with the high nonlinearities of Wankel engines so as to improve the fuel economy and emissions. By taking the unknown parameters as augmented engine states, an extended Kalman filter is designed to estimate the fuel puddle dynamics using only mass air flow (MAF) and lambda sensors. The complex nonlinear air-filling dynamics are lumped together and estimated using novel observer techniques. A newly proposed unknown input observer is compared with a dirty differentiation observer and then employed in the feedback AFR control design. Comparative simulations based on a calibrated benchmark engine model show that the proposed control can speed up the transient response and regulate the AFR around the stoichiometric value.

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    Rights statement: This is the author accepted manuscript (AAM). The final published version (version of record) is available online via IEEE at . Please refer to any applicable terms of use of the publisher.

    Accepted author manuscript, 314 KB, PDF document


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