Optical Investigations on a Multiple Spark Ignition System for Lean Engine Operation

Poggiani, Claudio; Cimarello, Alessandro; Battistoni, Michele; Grimaldi, Carlo N.; Re, Massimo Augusto Dal; Cesare, Matteo De

doi:10.4271/2016-01-0711

Cited by 25 publications

(11 citation statements)

References 23 publications

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“…Besides, in order to produce different autoignition sites as well as the following knock evolution processes, a series of spark strategies are used to control flame propagation headways. The multiple spark ignition is firstly introduced to reduce the cold start problems [20,21] and to extend the lean combustion limit and EGR tolerance while keeping low cycle-to-cycle variability [22][23][24][25][26][27], currently the multiple spark ignition is mainly used in highspeed internal combustion engines such as racing cars, motorcycles and outboard motors in attempts to eliminate missing and partial burn combustions, minimize the combustion variability, reduce the fuel consumption as well as UHC and NOx emissions [26,28,29]. Besides, Kartha et al [30] reported that multiple spark plug configuration yielded the least NOx emissions compared against single spark combustion with equivalent ignition energy, and specially, side spark ignition was ideal for low UHC and CO emissions.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on Knock Mechanism with Multiple Spark Plugs and Multiple Pressure Sensors

Shi¹,

Uddeen²,

An³

et al. 2020

SAE Technical Paper Series

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Engine knock is an abnormal phenomenon, which places barriers for modern Spark-Ignition (SI) engines to achieve higher thermal efficiency and better performance. In order to trigger more controllable knock events for study while keeping the knock intensity at restricted range, various spark strategies (e.g. spark timing, spark number, spark location) are applied to investigate on their influences on knock combustion characteristics and pressure oscillations. The experiment is implemented on a modified single cylinder Compression-Ignition (CI) engine operated at SI mode with port fuel injection (PFI). A specialized liner with 4 side spark plugs and 4 pressure sensors is used to generate various flame propagation processes, which leads to different auto-ignition onsets and knock development. Based on multiple channels of pressure signals, a bandpass filter is applied to obtain the pressure oscillations with respect to different spark strategies. Finally, the relationships among in-cylinder pressure, knock intensity, pressure fluctuation, heat release and measurement location, are analyzed to get better understanding on knock mechanism, influence factors and measurement methods. The main results show that: Igniting two spark plugs simultaneously brings higher knock amplitude than single spark ignition, however, adding more spark sites could effectively suppress the knock strength and rate of recurrence. A function (Y =-0.25X + 2.82) is fitted to illustrate the relations between the crank angle of 1st peak of knock oscillation and MAPO. Besides, the correlations among MAPO and other influential factors are evaluated. Moreover, the pressure sensors installed around the liner give different pressure fluctuations, which indicate the directionality of pressure wave transmission in cylinder during knock process.

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Section: Introductionmentioning

confidence: 99%

Experimental Study on Knock Mechanism with Multiple Spark Plugs and Multiple Pressure Sensors

Shi¹,

Uddeen²,

An³

et al. 2020

SAE Technical Paper Series

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“…Firstly, the multiple sparks were used to overcome the cold start problems in engine [29,30]. The multiple plugs were also used to reduce the cycle to cycle variations in lean limit and EGR studies [31][32][33]. In the recent years, the multiple spark plugs are applied in high speed internal combustion engines like racing cars and motorbikes to reduce the partial burn combustion, minimize the fuel consumptions along with UHC and NOx emissions [34][35][36][37].…”

Section: Figure 1 Normal and Knocking Combustion In The Enginementioning

confidence: 99%

“…However, these vibration modes can be circumferential, radial, or axial, as explained by Draper [23]. Because of the smaller height above the piston with respect to the cylinder bore during knock (near TDC), the axial mode can be neglected here [31]. The frequencies of different vibration modes can be examined using Eq.…”

Section: Acoustic Vibration Modesmentioning

confidence: 99%

“…In order to report the various vibration modes inside the cylinder, an FFT analysis is considered as the most significant approach. This is a comprehensively used method to transfer the pressure signal from the time domain to the frequency domain to obtain the logical components of vibration frequencies [31]. Figure 7 demonstrates a representative FFT spectrum of the pressure profile recorded by the top pressure sensor installed on the cylinder head.…”

Section: Acoustic Vibration Modesmentioning

confidence: 99%

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Investigations into the Effects of Spark Plug Location on Knock Initiation by using Multiple Pressure Transducers

Uddeen¹,

Shi²,

Tang³

et al. 2021

SAE Technical Paper Series

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Despite a long history of development, modern spark-ignition (SI) engines are still restricted in obtaining higher thermal efficiency and better performance by knock. Knocking combustion is an abnormal combustion phenomenon caused by the autoignition of unburned airfuel mixture ahead of the propagating flame front. This work describes investigations into the significance of spark plug location (with respect to inlet and exhaust valve position) on the knock formation mechanism. To facilitate the investigation, four spark plugs were installed in a specialized liner at four equispaced distinct locations to propagate flames from those locations, which provoked a distinct flame propagation from each and thus individual autoignition profiles. Six pressure transducers were arranged to precisely record the pressure oscillations, knock intensities, and combustion characteristics. Four of the six transducers were mounted on the circumference of the liner (each next to one of the spark plugs), one was placed at the center of the cylinder head, and one at a slight offset from the center of cylinder head. The results showed that the spark plug which was close to the exhaust valves triggered higher knock intensity along with earlier CA50, but the spark plug near the inlet valves caused weaker knock intensities for the same operating conditions. In addition, the study also covered the effect of swirl direction to suppress knock. A band pass filtering analysis was applied to estimate the pressure oscillations with respect to the spark plug locations, using data from the multiple pressure sensors. Furthermore, Fast Fourier Transform (FFT) analyses were implemented to estimate the frequency of the pressure oscillation resulting from knock. It was found that firing the spark plugs, near the inlet and between the inlet and exhaust valves promoted the (1, 0) acoustic mode effectively, while the spark plug near the exhaust valves caused the (1, 0) mode along with the (2, 0) acoustic mode for the same operating conditions, indicating that the autoignition was initiated near the cylinder walls.

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“…Engines operating with the traditional spark-ignition (SI) system are currently unfit to guarantee high performance together with low emissions at lean and/or diluted operating conditions [11][12][13][14][15]. Many attempts have been made out to improve the conventional SI combustion process by varying the discharge interval [16,17] or by improving the released thermal energy [18], but issues such as fouling, erosion, and heat loss through the electrodes have led automotive research to look for other solutions [19][20][21].…”

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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Optical Investigations on a Multiple Spark Ignition System for Lean Engine Operation

Cited by 25 publications

References 23 publications

Experimental Study on Knock Mechanism with Multiple Spark Plugs and Multiple Pressure Sensors

Experimental Study on Knock Mechanism with Multiple Spark Plugs and Multiple Pressure Sensors

Investigations into the Effects of Spark Plug Location on Knock Initiation by using Multiple Pressure Transducers

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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