Stabilized Combustion in a Spark Ignited Engine through a Long Spark Duration

Nakai, Masato; Nakagawa, Yasuhiko; Hamai, Kyugo; Sone, Masazumi

doi:10.4271/850075

Cited by 42 publications

(4 citation statements)

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“…Most experiments performed in SI engines focus on the ability of the spark plasma to ignite a given mixture and do not concentrate on the spark behaviour. These studies concentrate on obtaining the minimum ignition energy [12,15], extending the lean misfire limit [16][17][18], and reducing cycle-to-cycle variation in SI engines [16,19].…”

Section: Introductionmentioning

confidence: 99%

High-Speed Flow and Fuel Imaging Study of Available Spark Energy in a Spray-Guided Direct-Injection Engine and Implications on Misfires

Peterson

Sick

2010

International Journal of Engine Research

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The spark energy transferred under the highly stratified conditions during late injection in a spray-guided spark-ignition direct-injection (SG-SIDI) engine is not well characterized. The impact of high pressures, temperatures, velocities, and variations in local fuel concentration along with temporal and/or spatial variations on spark performance must be better characterized. Previous spark ignition studies have not addressed the full range of conditions that are present in SG-SIDI engines. Therefore, high-speed particle image velocimetry (PIV) experiments are conducted to characterize the spark energy dependence for a wide range of well-defined homogeneous fuel-air equivalence ratios (W 5 0-2.9) and average air velocities (0-8 m/s) in an optical SG-SIDI engine. A moderate dependence of spark energy on equivalence ratio is shown to exist with average values of spark energy increasing by 21 per cent for the equivalence ratio range of W 5 0-2.3. Air injection into the motored engine is used to prepare well-defined flow conditions without the complications of fuel concentration gradients that are present during fuel injection. This allows the study of the effects of velocity, shear strain rate, and vorticity on spark energy. The spark energy increases with velocity at the spark plug. This observation is consistent with findings reported in the literature for low-pressure conditions. A linear increase is shown between shear strain rate and spark energy, while vorticity and spark energy are only weakly correlated. Simultaneous high-speed PIV, planar laser-induced fluorescence, and spark-discharge electrical measurements are also performed in the optical SG-SIDI engine to measure flow properties and fuel concentrations under late injection. Operating parameters are chosen to be near peak indicated mean effective pressure performance, but they occasionally provide a random misfired or partial burned cycle. Misfired cycles occur under stoichiometric-to-lean mixtures and low velocities near the spark plug. The lower spark energies observed under these conditions are in agreement with the observations made under well-controlled mixture and flow conditions reported in this study. All mixture conditions found in misfiring and partially burning cycles are within the ignitability range and fall within the general population of all, predominantly well-burning, cycles. There is no predominant impact of shear strain rate and vorticity under late injection operation on misfires and partial burns.

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Section: Introductionmentioning

confidence: 99%

High-Speed Flow and Fuel Imaging Study of Available Spark Energy in a Spray-Guided Direct-Injection Engine and Implications on Misfires

Peterson

Sick

2010

International Journal of Engine Research

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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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“…The geometry of the spark plug and characteristics of the ignition system play important roles in the initiation of combustion. This is particularly true in lean-burn engines or those with high EGR rates [5][6][7][8][9]. The physics of the energy transfer from the spark to the surrounding gas and of the initiation of a selfsustaining combustion reaction in the gas are complex.…”

Section: Introductionmentioning

confidence: 99%

Spark Heat Transfer Measurements in Flowing Gases

Verhoeven

1997

Rev. Inst. Fr. Pét.

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RƒSUMƒ DES TRANSFERTS DE CHALEUR ENTRE UNE ƒTINCELLE DÕALLUMAGE ET DES ƒCOULEMENTS GAZEUXË partir de techniques basŽes sur lÕinterfŽromŽtrie holographique, lÕŽnergie totale transfŽrŽe par une Žtincelle aux gaz environnants a ŽtŽ mesurŽe en faisant varier la gŽomŽtrie des Žlectrodes de la bougie dÕallumage, la vitesse des gaz, la pression et le temps de charge de la bobine, cette derni•re Žtant un mod•le standard pour automobile. Pour les diffŽrentes combinaisons et valeurs des param•tres ŽtudiŽs, il a ŽtŽ observŽ une variation du "rendement dÕŽtincelle" (rapport entre lÕŽnergie transmise aux gaz par lÕŽtincelle ˆ lÕŽnergie Žlectrique fournie ˆ la bougie) allant de 20 ˆ 60 %. Pour des conditions rŽelles de fonctionnement dans un moteur, on peut estimer que lÕŽnergie transmise aux gaz par le syst•me dÕallumage est voisine de 30 mJ. Il est aussi montrŽ comment ces mesures de lÕŽnergie totale transfŽrŽe aux gaz, peuvent •tre exploitŽes pour caractŽriser en fonction du temps, la puissance transmise dans lÕŽtincelle gŽnŽrŽe par un syst•me standard dÕallumage inductif. SPARK HEAT TRANSFER MEASUREMENTS IN FLOWING GASESUsing a technique based on holographic interferometry, the total energy transferred from a spark to the surrounding gases was measured for a number of spark plug electrode geometries, flow velocities, gas pressures and coil charge times. A standard automotive ignition coil was used. For the combinations of parameter values studied, we observed "spark efficiencies" (ratio of the energy in the gas heated by the spark to the electrical energy supplied to the spark plug) of from 20 to 60 percent. For realistic engine conditions we estimate the quantity of energy transferred to the gas by our ignition system to be roughly 30 mJ. We show how these measurements of total energy transferred to the gas can be used to estimate the spark power vs. time characteristic of a standard inductive ignition system. MEDICIîN DE LAS TRANSFERENCIAS DE CALOR ENTRE UNA CHISPA DE ENCENDIDO Y LOS FLUJOS GASEOSOSTomando como punto de partida las tŽcnicas fundadas en la interferometr'a hologr ‡fica, se ha procedido a la medici-n de la energ'a total transferida por una chispa a los gases circundantes, haciendo variar la geometr'a de los electrodos de la buj'a de encendido, la velocidad de los gases, la presi-n y el tiempo de carga de la bobina, correspondiendo est ‡ oeltima a un modelo est ‡ndar para autom-vil. Se ha observado, para las distintas combinaciones y valores de los par ‡metros estudiados, una variaci-n del "rendimiento de la chispa" (relaci-n entre la energ'a transmitida a los gases por la chispa a la energ'a elŽctrica suministrada a la buj'a) que oscila entre un 20 y un 60 %. Operando en condiciones reales de funcionamiento de un motor, se puede considerar que la energ'a transmitida a los gases por el sistema de encendido, se aproxima de los 30 mJ. TambiŽn se indica c-mo estas mediciones de la energ'a total transferida a los gases pueden ser aprovechadas para caracterizar, en funci-n del tiempo, la potencia transmitida en ...

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Stabilized Combustion in a Spark Ignited Engine through a Long Spark Duration

Cited by 42 publications

References 1 publication

High-Speed Flow and Fuel Imaging Study of Available Spark Energy in a Spray-Guided Direct-Injection Engine and Implications on Misfires

High-Speed Flow and Fuel Imaging Study of Available Spark Energy in a Spray-Guided Direct-Injection Engine and Implications on Misfires

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

Spark Heat Transfer Measurements in Flowing Gases

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