Local Air-Fuel Ratio Measurements Using the Spark Plug as an Ionization Sensor

Reinmann, Raymond; Saitzkoff, André; Mauß, Fabian

doi:10.4271/970856

Cited by 86 publications

(22 citation statements)

References 10 publications

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“…There is no detectable second ion-current peak at very lean conditions with this ion-current measurement system. It is a known fact that the ion-current signal (especially the second peak) becomes very small at lean conditions [8], [9]. With EGR there is a strong signal, see Figure 14.…”

Section: Ion-current Measurementsmentioning

confidence: 94%

The Potential of Using the Ion-Current Signal for Optimizing Engine Stability - Comparisons of Lean and EGR (Stoichiometric) Operation

Einewall¹,

Tunestål²,

Johansson³

2003

SAE Technical Paper Series

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Ion current measurements can give information useful for controlling the combustion stability in a multi-cylinder engine. Operation near the dilution limit (air or EGR) can be achieved and it can be optimized individually for the cylinders, resulting in a system with better engine stability for highly diluted mixtures. This method will also compensate for engine wear, e.g. changes in volumetric efficiency and fuel injector characteristics. Especially in a port injected engine, changes in fuel injector characteristics can lead to increased emissions and deteriorated engine performance when operating with a closed-loop lambda control system. One problem using the ion-current signal to control engine stability near the lean limit is the weak signal resulting in low signal to noise ratio. Measurements presented in this paper were made on a turbocharged 9.6 liter six cylinder natural gas engine with port injection. Each cylinder was individually controlled by a cylinder control module (CCM). A high turbulence combustion chamber was used to be able to operate with highly diluted mixtures. Comparisons between lean and EGR (stoichiometric) operation were made to investigate the potential of using the ion-current signal to control engine stability (cylinder to cylinder and cycle to cycle variations). A much stronger ion-current signal was found with EGR compared to lean operation, for the same load and comparable emissions.

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Section: Ion-current Measurementsmentioning

confidence: 94%

The Potential of Using the Ion-Current Signal for Optimizing Engine Stability - Comparisons of Lean and EGR (Stoichiometric) Operation

Einewall¹,

Tunestål²,

Johansson³

2003

SAE Technical Paper Series

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“…Some of the earliest experimental work in this area was conducted in 1960s and 1970s (see Clements and Smy, 1976, and references therein) and has continued to date (Anderson, 1986;Henein et al, 2010;Miyata et al, 1993;Shimasaki et al, 1993;Tisch et al, 2008;Yoshiyama and Tomita, 2002;Yoshiyama et al, 2000). While an abundance of research exists on experimental investigation into ion current measurements, relatively fewer numerical investigations have sought to identify the charged species present in the combusting mixture (Ahmedi et al, 2003(Ahmedi et al, , 2004Franke et al, 2003;Naoumov et al, 2002;Reinmann et al, 1997;Saitzkoff et al, 1996;Yamashita et al, 2009). The correlation between ionization current signature and pressure trace in combusting mixtures is of great interest in spark-ignited (SI) internal combustion engines because it can serve as a diagnostic tool with little modification to the existing setup, since the spark plug is an integral part of the SI engine.…”

Section: Current Signature In a Constant-volume Combustion Chamber 337mentioning

confidence: 98%

Analysis of the Current Signature in a Constant-Volume Combustion Chamber

Aithal

2013

Combustion Science and Technology

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Identifying charged species and their relative concentrations as a function of initial mixture composition, temperature, and pressure can play an important role in the diagnostics and control of combustion devices. This article aims to identify important charged species and their temporal variation in a spark-ignited methane/air mixture using the equilibrium constant method. The equilibrium composition of 20 neutral and seven charged species [(e À ), CHO þ , H 3 O þ , NO þ , OH À , O À 2 , O À ] was obtained using a novel adaptation of the Newton-Raphson method for highly stiff nonlinear system of equations. A two-zone combustion model was used to study the effect of air-fuel ratio (AFR) on the temporal variation of charged species concentration. Temporal variation of the current computed from the equilibrium concentration of charged species was found to compare well with experimental data for several AFRs.

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“…While classical approaches evaluate the signal taken from an A/F sensor, which is mounted behind the confluence point of the exhaust manifold, some alternatives are torque-based approaches [2], which take advantage of a functional relation between torque production and A/F by measurement of the crankshaft acceleration. Also, alternative sensor signals, such as the ion current from a modified spark plug [3,4] and pressure-based concepts [5] have been considered. In reference [6], the turbocharger speed of a diesel engine is used for detection.…”

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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Local Air-Fuel Ratio Measurements Using the Spark Plug as an Ionization Sensor

Cited by 86 publications

References 10 publications

The Potential of Using the Ion-Current Signal for Optimizing Engine Stability - Comparisons of Lean and EGR (Stoichiometric) Operation

The Potential of Using the Ion-Current Signal for Optimizing Engine Stability - Comparisons of Lean and EGR (Stoichiometric) Operation

Analysis of the Current Signature in a Constant-Volume Combustion Chamber

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

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