Prospects of Ignition Enhancement

Maly, R.; Saggau, B.; Wagner, Eberhard; Ziegler, G.

doi:10.4271/830478

Cited by 38 publications

(13 citation statements)

References 9 publications

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“…For spark plugs, numerous studies have been performed on the effects of the rate and duration over which energy is delivered to the spark, attempting to determine the optimum spark power, energy, and duration (e.g., Anderson and Lim, 1985;Anderson, 1987;Maly et al, 1983;Pischinger and Heywood, 1988;Cho et al, 1992). However, the results from different researchers are not all consistent.…”

Section: Implications From Studies Of Spark Plug Wearmentioning

confidence: 81%

Railplug Ignition System for Enhanced Engine Performance and Reduced Maintenance

Ezekoye¹,

Hall²,

Matthews³

2005

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This Final Technical Report discusses the progress that was made on the experimental and numerical tasks over the duration of this project. The primary objectives of the project were to 1) develop an improved understanding of the spark ignition process, and 2) develop the railplug as an improved ignitor for large bore stationary natural gas engines.We performed fundamental experiments on the physical processes occurring during spark ignition and used the results from these experiments to aid our development of the most complete model of the spark ignition process ever devised. The elements in this model include 1) the dynamic response of the ignition circuit, 2) a chemical kinetics mechanism that is suitable for the reactions that occur in the plasma, 3) conventional flame propagation kinetics, and 4) a multi-dimensional formulation so that bulk flow through the spark gap can be incorporated. This model (i.e., a Fortran code that can be used as a subroutine within an engine modeling code such as KIVA) can be obtained from Prof. Ron Matthews at rdmatt@mail.utexas.edu or Prof. DK Ezekoye at dezekoye@mail.utexas.edu.Fundamental experiments, engine experiments, and modeling tasks were used to help develop the railplug as a new ignitor for large bore natural gas engines. As the result of these studies, we developed a railplug that could extend the Lean Stability Limit (LSL) of an engine operating at full load on natural gas from φ = 0.59 for operation on spark plugs down to φ = 0.53 using railplugs with the same delivered energy (0.7 J). However, this delivered energy would rapidly wear out the spark plug. For a conventional delivered energy (<0.05 J), the LSL is φ = 0.63 for a spark plug. Further, using a permanent magnet to aid the plasma movement, the LSL was extended to φ = 0.54 for a railplug with a delivered energy of only 0.15 J/shot, a typical discharge energy for commercial capacitive discharge ignition systems. Here, it should be noted that railplugs and the associated ignition circuit should not cost much more than a conventional spark ignition system. Additionally, it is believed that the railplug performance can be further improved via continued research and development.iii TABLE OF CONTENTS Abstract iii EXECUTIVE SUMMARYThis Final Technical Report discusses the progress that was made on the experimental and numerical tasks over the duration of this project. The primary objectives of the project were to 1) develop an improved understanding of the spark ignition process, and 2) develop the railplug as an improved ignitor for large bore stationary natural gas engines.Due to these two objectives, the experimental subtasks involved 1) detailed measurements regarding the physical processes occurring during spark ignition, and 2) measurements of the factors that affect railplug performance. Similarly, the modeling subtasks involved developing an improved model for the conventional spark ignition process and developing a model for railplug performance and ignition.The four phases of spark ignition are ...

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Section: Implications From Studies Of Spark Plug Wearmentioning

confidence: 81%

Railplug Ignition System for Enhanced Engine Performance and Reduced Maintenance

Ezekoye¹,

Hall²,

Matthews³

2005

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“…Once the spark is formed, most of the energy is delivered to resistances in the transformer, spark plug wires and spark plugs. This operating level is adequate (but not necessarily optimum) for older and most modern engines, but will not meet the needs of future lean burn and some alternate fuel engines that require higher energy discharges to effectively ignite the air/fuel mixtures [2][3][4][5]. To meet the requirements for increased ignition power and energy, ignition systems will have to be designed to operate at higher transfer efficiencies.…”

Section: Introductionmentioning

confidence: 99%

Ignition study of a petrol/CNG single cylinder engine

Khan

Saleem

Mirza

2005

Intelligent Systems in Design and Manufacturing VI

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Benefits of laser ignition over the electrical ignition system for Compressed Natural Gas (CNG) engines have fuelled automobile industry and led to an extensive research on basic characteristics to switch over to the emerging technologies. This study was undertaken to determine the electrical and physical characteristics of the electric spark ignition of single cylinder petrol/CNG engine to determine minimum ignition requirements and timeline of ignition events to use in subsequent laser ignition study. This communication briefly reviews the ongoing research activities and reports the results of this experimental study. The premixed petrol and CNG mixtures were tested for variation of current and voltage characteristics of the spark with speed of engine. The current magnitude of discharge circuit was found to vary linearly over a wide range of speed but the stroke to stroke fire time was found to vary nonlinearly. The DC voltage profiles were observed to fluctuate randomly during ignition process and staying constant in rest of the combustion cycle. Fire to fire peaks of current amplitudes fluctuated up to 10% of the peak values at constant speed but increased almost linearly with increase in speed. Technical barriers of laser ignition related to threshold minimum ignition energy, inter-pulse durations and firing sequence are discussed. Present findings provide a basic initiative and background information for designing suitable timeline algorithms for laser ignited leaner direct injected CNG engines.

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“…In other words, attempting to determine the optimum spark power, energy and/or duration. These include studiesof the effect of long duration sparks [5,8,9], multiple sparks [10] and shortduration sparks [5,6,8,[11][12][13][14]. Of specific interestin the study reported in this paper is the effect of shortduration, breakdown sparks.…”

Section: Introductionmentioning

confidence: 99%

Spark ignited turbulent flame kernel growth. Annual report, January--December 1991

Santavicca¹

1994

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An experimental study of the effect of spark power on the growth rate of spark-ignited flame kernels was conducted in a turbulent flow system at 1 atm, 300 K conditions. All measurements were made with premixed, propane-air at a fuel/air equivalence ratio of 0.93, with 0%, 8% or 14% dilution. Two flow conditions were studied: a low turbulence intensity case with a mean velocity of 1.25 m/sec and a turbulence intensity of 0.33 m/sec, and a high turbulence intensity case with a mean velocity of 1.04 m/sec and a turbulence intensity of 0.88 m/sec. The growth of the spark-ignited flame kernel was recorded over a time interval from 83/lsec to 20 msec following the start of ignition using high speed laser shadowgraphy. In order to evaluate the effect of ignition spark power, tests were conducted with a long duration (-4 msec) inductive discharge ignition system with an average spark power of-14 watts and two short duration (- .-100 nsec) breakdown ignition systems with average spark powers of-6 x 104 and-6 x 105 watts. The results showed that increased spark power resulted in an increased growth rate, where the effect of short duration breakdown sparks was found to persist for times of the order of milliseconds. The effectiveness of increased spark power was found to be less at high turbulence and high dilution conditions. Increased spark power had a greater effect on the 0-5 mm burn time than on the 5-13 mm burn time, in part because of the effect of breakdown energy on the initial size of the flame kernel. And finally, when spark power was increased by shortening the spark duration while keeping the effective energy the same there was a significant increase in the misfire rate, however when the spark power was further increased by increasing the breakdown energy the misfire rate dropped to zero.

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Prospects of Ignition Enhancement

Cited by 38 publications

References 9 publications

Railplug Ignition System for Enhanced Engine Performance and Reduced Maintenance

Railplug Ignition System for Enhanced Engine Performance and Reduced Maintenance

Ignition study of a petrol/CNG single cylinder engine

Spark ignited turbulent flame kernel growth. Annual report, January--December 1991

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