Journal ArticleDOI
Combustion imaging from electrical impedance measurements
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TLDR
In this article, the authors used electrical capacitance tomography (ECT) to measure both the change in permittivity and change in conductivity, yielding additional information on the flame composition.Abstract:
The development of stray-immune circuits to measure very small floating capacitances has enabled the technique of electrical capacitance tomography (ECT) to be developed. Burning fuel, for example in an internal combustion engine, produces a high concentration of ions, thus modifying the dielectric constant of the combustion volume. Thus ECT can be applied to produce tomographic images inside a combustion chamber, independent of flame luminosity. However, the major effect of the increase in ion concentration is to increase the conductivity of the volume. The ECT technique has been extended to measure both the change in permittivity and change in conductivity, yielding additional information on the flame composition. Current spatial and temporal resolution is poor but developments are in hand to overcome these limitations. Alternatively, the way forward may well be to abandon images and instead use extremely simple and cheap sensors to monitor knock on a cycle-by-cycle basis. An alternative use of such a simple sensor would be to monitor cycle dispersion in a lean burn engine. Both these techniques could help minimize fuel consumption, whilst maximizing power output and keeping emissions low.read more
Citations
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Journal ArticleDOI
Image reconstruction algorithms for electrical capacitance tomography
Wuqiang Yang,Lihui Peng +1 more
TL;DR: In this article, a review of existing image reconstruction algorithms for electrical capacitance tomography (ECT) is presented, including linear back-projection, singular value decomposition, Tikhonov regularization, Newton-Raphson, steepest descent method, Landweber iteration, conjugate gradient method, algebraic reconstruction techniques, simultaneous iterative reconstruction techniques and model-based reconstruction.
Journal ArticleDOI
Design of electrical capacitance tomography sensors
TL;DR: In this article, the authors discuss the principles of ECT sensors, but mostly focus on key issues for ECT sensor design, with reference to some existing ECT-based sensors as a good understanding of the key issues would help optimization of the design of the sensor.
Journal ArticleDOI
Real-time ultrasound process tomography for two-phase flow imaging using a reduced number of transducers
TL;DR: The impact on the image quality due to the reduction of the number of transducers is discussed, and different approaches such as multiple receiver data acquisition and nonlinear thresholding are explored.
Journal ArticleDOI
Recent Advances in Flame Tomography
TL;DR: In this paper, the authors identify the challenges in flame tomography and review existing techniques for the quantitative characterization of flames, including passive optical tomography, laser-based and electrical tomography.
Patent
Multiple excitation capacitance polling for enhanced electronic capacitance tomography
Robert X. Gao,Zhaoyan Fan +1 more
TL;DR: In this paper, a novel sensing technique, termed Multiple Excitation Capacitance Polling (MECaP), is proposed to improve the efficiency of electrical capacitance tomography (ECT).
References
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Journal ArticleDOI
Tomographic imaging of two-component flow using capacitance sensors
TL;DR: In this article, the authors describe a tomographic flow imaging system based on capacitance sensors, which uses eight capacitance electrodes to perform a body scan of the fluid-conveying pipe, and a linear back projection algorithm is developed to reconstruct the cross-sectional image of the two-component flow from the measured capacitance values.
Proceedings ArticleDOI
Detection of Flame Propagation During Knocking Combustion by Optical Fiber Diagnostics
U. Spicher,H.-P. Kollmeier +1 more
TL;DR: In this paper, a single-cylinder spark ignition engine with optical fibers coupled with photo-multipliers was investigated for the phenomenon of knocking (detonation) during combustion.
Journal ArticleDOI
The variation of ionization with air/fuel ratio for a spark‐ignition engine
R. M. Clements,P. R. Smy +1 more
TL;DR: In this paper, a negatively biased flush-mounted planar probe operated both in a pulsed and dc mode has been used to measure the ionization density in the plasma generated by combustion in a single-cylinder spark-ignition engine.
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