Comparative Optical and Thermodynamic Investigations of High Frequency Corona- and Spark-Ignition on a CV Natural Gas Research Engine Operated with Charge Dilution by Exhaust Gas Recirculation

Marko, Fabian; König, Gerhard; Schöffler, Tobias; Bohne, Steffen; Dinkelacker, Friedrich

doi:10.1007/978-3-319-45504-4_18

Cited by 19 publications

(18 citation statements)

References 6 publications

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“…Note that no further information regarding combustion evolution was provided from the optical point of view, since this analysis was focused on the flame onset detection. Such results can be found in other works [11,14,15,32].…”

Section: Streamer-to-flame Transitionsupporting

confidence: 86%

“…LTP igniters were found to be capable of ensuring a higher lean/diluted combustion robustness. At the same time, electrode erosion or fouling-typical of spark igniters-was found to be minimized [6,12,[14][15][16]. These advantages are related to the three combustion enhancement pathways: thermal, kinetic, and transport [17].…”

Section: Introductionmentioning

confidence: 99%

“…These advantages are related to the three combustion enhancement pathways: thermal, kinetic, and transport [17]. Among all the LTP systems, RF corona was intensively studied in recent years [18][19][20][21], especially in optical engines [11,14,22], to characterize its ability to speed up the early flame kernel generation [15].…”

Section: Introductionmentioning

confidence: 99%

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An Optical Method to Characterize Streamer Variability and Streamer-to-Flame Transition for Radio-Frequency Corona Discharges

et al. 2020

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In recent years, radio-frequency corona ignition gained increasing interest from the engine research community because of its capability to extend the engine stable operating range in terms of lean and EGR dilution. The corona discharge generates streamers coming from a star-shaped electrode, generally consisting of four or five tips. The temporal and spatial variability of such streamers in length, orientation, and branching can be factors that affect the combustion onset and, therefore, engine cycle-to-cycle variability. Generally, the latter is reduced with respect to a conventional spark igniter at the same air–fuel ratio, but still present. In this work, analysis on the corona discharge and on the subsequent combustion onset was carried out in an optically accessible engine by means of the detection, via high-speed camera, of the natural luminosity of streamers and flames. A method to characterize spatial and temporal variability in motored conditions is firstly presented. A statistical analysis of the streamer behavior was performed, by separately analyzing the streamers generated by each tip of the star-shaped electrode. Finally, an original method aimed at determining the moment of the first flame appearance, caused by the combustion onset, is presented. The outcome of this work can be used to improve the knowledge on corona discharge, in particular on the stochastic behavior that characterizes the streamers. The presented optical analysis can also be adapted to other volumetric, single- or multi-point ignition systems.

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Section: Streamer-to-flame Transitionsupporting

confidence: 86%

Section: Introductionmentioning

confidence: 99%

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An Optical Method to Characterize Streamer Variability and Streamer-to-Flame Transition for Radio-Frequency Corona Discharges

et al. 2020

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“…In this work, the subject of investigation is the Radio-Frequency Advanced Corona Ignition System (RF ACIS ), based on low temperature plasma and characterised by a single electrode, fed by a 1 MHz AC current. It has been proved that the RF corona discharge extends the lean air-to-fuel mix combustion limit with respect to the conventional spark igniter [53,54,55,56] and, as other low temperature plasma igniters, the EGR dilution tolerance [57,58,59]. This is possible by stabilising the combustion ignition with a large area flame kernel [60,61] and by reducing the cycle-to-cycle variability for a given EGR rate with bigger impact on naturally aspirated loads than on boosted ones [62].…”

Section: Introductionmentioning

confidence: 99%

Experimental characterisation of the thermal energy released by a Radio-Frequency Corona Igniter in nitrogen and air

et al. 2020

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The Radio-Frequency Corona Ignition System is characterised by a wide initial combustion volume and precursors production, via radical insemination by the streamers, in addition to high released thermal energy. These features lead to faster combustion, a higher tolerance for lean mixtures and EGR dilutions and, in general, more adaptability. The thermal energy released by the igniter to the surrounding medium can help to understand the performance, the behaviour and the application range. This paper proposes a systematic experimental analysis of the thermal energy released by the igniter at room temperature, via pressure-based calorimetry. This analysis, carried out at different pressures (up to 10 bar) and medium type (air or nitrogen), is extended to the whole range of the corona igniter control parameters, namely streamer duration and driving voltage. The latter is proportional to the maximum electrode voltage, as shown in the model here presented, and as confirmed by experiments. The results show, for all the vessel pressures, the high energetic efficiency of the ignition system and the high amount of the released energy. The latter is found to increase linearly with the corona streamers duration and quickly with the driving voltage up to the streamer-to-arc transition threshold. The efficiency tends to reach a defined upper limit. For each tested point, the energy released to pure nitrogen is higher than to air, which evidences the impact of the oxygen presence under streamer exposure.

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“…One of the most interesting LTP solutions is represented by the Advanced Corona Ignition Systems (ACIS) [32,33], to whose family belong the corona streamer-type igniter (CSI) [34,35] and the barrier discharge igniter (BDI) [36,37]. Generally speaking, the corona-effect is based on the production of ionization waves, namely streamers, produced by a high-frequency electric field once exceeding the activation threshold [38,39].…”

Section: Introductionmentioning

confidence: 99%

Investigation of the Lean Stable Limit of a Barrier Discharge Igniter and of a Streamer-Type Corona Igniter at Different Engine Loads in a Single-Cylinder Research Engine

Ricci

Petrucci

Cruccolini

et al. 2020

The First World Energies Forum—Current and Future Energy Issues

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Currently, the Radio-Frequency Corona Ignition systems represent an important solution for reducing pollutant emissions and fuel consumption related to Internal Combustion Engines, while at the same time ensuring high performance. These igniters are able to extend the lean stable limit by increasing the early flame growth speed. Kinetic, thermal, and ionic effects, together with the peculiar configuration of the devices, allow the combustion process to start in a wider region than the one involved with the traditional spark. In this work two corona igniters, namely a Barrier Discharge Igniter and a Corona Streamer Igniter, were tested in a single-cylinder research engine fueled with gasoline at different engine loads in order to investigate the igniters’ performance through indicated analysis and pollutant emissions analysis. For each operating point, the devices’ control parameters were set to ensure maximum energy releasement into the medium with the aim of investigating, at the extreme operating conditions, the capability of the devices to extend the lean stable limit of the engine. The corona igniters were tested on a constant volume calorimeter as well, reproducing the engine pressure conditions at the corresponding ignition timing. The target was to give an estimation of the thermal energy released during the discharge and then to compare their capability to provide high-stability energy.

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Comparative Optical and Thermodynamic Investigations of High Frequency Corona- and Spark-Ignition on a CV Natural Gas Research Engine Operated with Charge Dilution by Exhaust Gas Recirculation

Cited by 19 publications

References 6 publications

An Optical Method to Characterize Streamer Variability and Streamer-to-Flame Transition for Radio-Frequency Corona Discharges

An Optical Method to Characterize Streamer Variability and Streamer-to-Flame Transition for Radio-Frequency Corona Discharges

Experimental characterisation of the thermal energy released by a Radio-Frequency Corona Igniter in nitrogen and air

Investigation of the Lean Stable Limit of a Barrier Discharge Igniter and of a Streamer-Type Corona Igniter at Different Engine Loads in a Single-Cylinder Research Engine

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