Non–Ideal Properties of ZrO<sub>2</sub> and TiO<sub>2</sub> Exhaust Gas Oxygen Sensors

Shulman, M A; Hamburg, D. R.

doi:10.4271/800018

Cited by 16 publications

(5 citation statements)

References 9 publications

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“…In [15], it was shown that cylinder-to-cylinder A/F differences result in a closed-loop lean shift in controlled A/F due to preferential diffusion of H 2 and CO across the HEGO sensor upstream of the catalyst. This control-point shift causes a dramatic reduction in NO x conversion efficiency due to the precipitous nature of the TWC characteristic away from stoichiometry.…”

Section: A/f Control For Pfi Enginesmentioning

confidence: 99%

Automotive Powertrain Control - A Survey

Cook

Sun²,

Buckland

et al. 2008

Asian Journal of Control

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This paper surveys recent and historical publications on automotive powertrain control. Control-oriented models of gasoline and diesel engines and their aftertreatment systems are reviewed, and challenging control problems for conventional engines, hybrid vehicles and fuel cell powertrains are discussed. Fundamentals are revisited and advancements are highlighted. A comprehensive list of references is provided.

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Section: A/f Control For Pfi Enginesmentioning

confidence: 99%

Automotive Powertrain Control - A Survey

Cook

Sun²,

Buckland

et al. 2008

Asian Journal of Control

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“…Importantly, feedgas and tailpipe A/F measurements are affected by different types of inaccuracy. Upstream of the catalyst, non-equilibrium effects in the exhaust gas result in a systematic bias error in the sensor [4], [8], [9], [11], [14]. This bias is in part due to incomplete catalysis of CO on the sensor substrate and in lesser part to N Ox; an additional confounding factor is the large discrepancy in the diffusion rate of H 2 with respect to other species present in the exhaust gas.…”

Section: Air-fuel Ratio Sensormentioning

confidence: 99%

“…In addition, it will be assumed that the close-coupled and underbody catalysts have equal conversion efficiencies and that the cascade of the two catalysts has the same overall efficiency as the single TWC for each of N Ox and HC. In particular, in (14), for each pollutant, η CC = η U B (conversion efficiencies at stoichiometry are HC = 93.37% and N Ox = 97.12%), with η as in Figure 5.…”

Section: Control Strategy For Two Catalysts In Seriesmentioning

confidence: 99%

Dual-UEGO active catalyst control for emissions reduction: design and experimental validation

Fiengo

Grizzle

Cook³

et al. 2005

IEEE Trans. Contr. Syst. Technol.

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This paper investigates active control of an aftertreatment system for a conventional spark ignition engine equipped with one or two three-way catalysts and two oxygen sensors. The control objective is to maximize the simultaneous conversion efficiencies of oxides of nitrogen and unburned hydrocarbons. Linear exhaust gas oxygen sensors are used to measure air-fuel ratio upstream and downstream of each catalyst. A series controller configuration is adopted. The upstream controller provides relatively rapid response to disturbances on the basis of measured feedgas air-fuel ratio, while the downstream controller uses the feedgas and post-catalyst air-fuel ratio measurements to compensate for the bias corrupting the feedgas air-fuel ratio measurement. The performance and robustness of the proposed control system in the face of noise and model uncertainty are first evaluated through extensive simulations. The control strategy is then experimentally verified in a dynamometer test cell and its performance compared with an existing proprietary controller that is based on the more common switching-type air-fuel ratio sensors.

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“…The topic is of current interest for the automotive industry since future legislation will require an A/F maldistribution to be diagnosed. The authorities have been motivated by the fact that an A/F maldistribution increases exhaust emissions [1] and accelerates the ageing of the catalyst. To compensate rather than just to diagnose is specifically interesting for the manufacturers since it allows them to optimize their components in terms of cost while keeping the emissions within the legislative requirements.…”

Section: Introductionmentioning

confidence: 99%

Robustness analysis of a Fourier-based strategy for cylinder-individual air–fuel ratio control

Schick

Onder

Guzzella

2011

Proceedings of the Institution of Mechanical Engineers, Part D:

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The paper investigates the robustness of a cylinder-to-cylinder air-fuel ratio controller that aims to reduce the exhaust emissions of automotive gasoline engines with spark ignition. A hardware configuration is considered where one wide-range sensor that measures the air-fuel ratio is mounted downstream of the confluence point of an exhaust manifold whose runners are linked to up to five cylinders. An uncertainty analysis is carried out for the closedloop system with a controller based on Fourier analysis. First, a sensor non-linearity is modelled as an uncertainty and the robustness margins are investigated. With existing observers, the control loop can have a marginal robustness for systems with an even number of cylinders per sensor. For uneven cylinder numbers, however, the loop is always robust. The class of observers considered uses for reconstruction only the necessary number of spectral components of the sensor signal. A modified observer is proposed that also evaluates available redundant spectral information. As a result, the robustness is fully recovered for even numbers of cylinders and further improved for uneven numbers. The robustness is validated on an engine test-bench. Finally, a more complicated case of model uncertainty is investigated where the superimposing signals that originate from the individual cylinders are assumed to be uncertain.

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Non–Ideal Properties of ZrO₂ and TiO₂ Exhaust Gas Oxygen Sensors

Cited by 16 publications

References 9 publications

Automotive Powertrain Control - A Survey

Automotive Powertrain Control - A Survey

Dual-UEGO active catalyst control for emissions reduction: design and experimental validation

Robustness analysis of a Fourier-based strategy for cylinder-individual air–fuel ratio control

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Non–Ideal Properties of ZrO2 and TiO2 Exhaust Gas Oxygen Sensors

Cited by 16 publications

References 9 publications

Automotive Powertrain Control - A Survey

Automotive Powertrain Control - A Survey

Dual-UEGO active catalyst control for emissions reduction: design and experimental validation

Robustness analysis of a Fourier-based strategy for cylinder-individual air–fuel ratio control

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Product

Resources

About

Non–Ideal Properties of ZrO₂ and TiO₂ Exhaust Gas Oxygen Sensors