State feedback based control of air-fuel-ratio using two wide-band oxygen sensors

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

5 Scopus citations


This paper proposes an observer-based state feedback control for controlling both the air-fuel-ratio (AFR) and the oxygen level of the three-way catalytic converter (TWC) in port-fuel-injection automotive gasoline engines. The operation of TWCs depends on the combustion mixture's air-fuel ratio as well as the oxygen storage level of the TWC. Accurate control of the air-fuel ratio is therefore required. TWCs can store oxygen from the exhaust gas when the exhaust gas is lean and can use up the stored oxygen when the exhaust gas is rich. Measurements of the air to fuel ratio are taken using oxygen sensors (UEGO) before and after the catalytic stage. The goal of this work is to develop control schemes that use the measurement of both UEGO sensors and thereby aim at improving the AFR control performance. Simulation results demonstrate that the proposed observer-based state feedback control can, in comparison with a PID controller, improve the efficiency of the operation of the TWC by maintaining the oxygen level at 50 % while regulating AFR to the optimized stoichiometric ratio.

Original languageEnglish (US)
Title of host publication2015 10th Asian Control Conference
Subtitle of host publicationEmerging Control Techniques for a Sustainable World, ASCC 2015
EditorsHazlina Selamat, Hafiz Rashidi Haruna Ramli, Ahmad Athif Mohd Faudzi, Ribhan Zafira Abdul Rahman, Asnor Juraiza Ishak, Azura Che Soh, Siti Anom Ahmad
PublisherInstitute of Electrical and Electronics Engineers Inc.
ISBN (Electronic)9781479978625
StatePublished - Sep 8 2015
Externally publishedYes
Event10th Asian Control Conference, ASCC 2015 - Kota Kinabalu, Malaysia
Duration: May 31 2015Jun 3 2015

Publication series

Name2015 10th Asian Control Conference: Emerging Control Techniques for a Sustainable World, ASCC 2015


Conference10th Asian Control Conference, ASCC 2015
CityKota Kinabalu


  • Air-fuel ratio
  • feed gas
  • mass air flow
  • separation principle
  • state feedback
  • tailpipe gas
  • three-way catalytic converter

ASJC Scopus subject areas

  • Control and Systems Engineering


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