Technical evaluation of vehicle ignition systems: conduct differences between a high energy capacitive system and a standard inductive system

The development of the automotive world experienced rapid development, and the most prominent development was in the ignition system. In this study will be discussed about the gasoline motor ignition system, especially the effect of spark plug gap on the power produced by the gasoline engine. The aim of research is to produce a good combustion process in the engine combustion chamber by determining the distance of the spark plug so that the sparks produced are perfect. The right spark plug gap will produce perfect combustion and the power produced will also be in accordance with the specifications of the engine. In order to maintain good spark plug work, it needs to be done in a maintenance manner to determine the extent of the effect of spark plug gap on the engine power of the gasoline motor. As for what will be examined in this study is the engine speed and engine power which is influenced by the distance of the spark plug to produce engine power on the gasoline motor. The method used in this study in the research is by using the direct method of conducting research in Cv. Prosperous motorbike. Materials used in research, one unit of Toyota Innova, with equipment measuring instruments and keys needed. In the study measurements were taken by measuring the distance of spark plug gap from 0.8 mm to the normal power, 0.6 mm the effect on power is not good because at high speed the fire jump is not large so the combustion is not perfect, and 1 mm the effect on the power The result is very low because the low and high speed sparks are unable to burn the fuel mixture. The results show differences in engine speed and power produced by the engine on a gasoline motor. To produce perfect engine power, it is necessary to do routine maintenance, especially the ignition system for spark plugs so that ignition and engine power are produced as stable as the specifications.

Running an internal combustion engine with diluted methane/air mixtures has a potential of reducing emissions and increasing efficiency. However, diluted mixtures need high ignition energy in a sufficiently large volume, which is difficult to accomplish. Increasing the spark duration has shown to be a promising way of delivering more energy into the diluted charge, but this requires a more sophisticated ignition system. This work focuses on evaluating the effects regarding enhancing early flame development, reducing cyclic variations and extending the lean limit using a new capacitive ignition system as compared to a conventional inductive ignition system. The new system offers the opportunity to customise the spark by altering the electric pulse train characteristics choosing the number of pulses, the length of the individual pulses as well as the time delay between them. Several different spark configurations were evaluated for the new capacitive system, including varying spark duration between approximately 0.5-1.2 ms and maximum current levels of 0.2-0.4 A. Results show that longer spark duration and faster initial energy deposition has a positive effect on the lean limit and the combustion stability, while the current level shows little or no effect on these variables. The more advanced capacitive system is capable of delivering more energy and longer spark duration, resulting in reduced cyclic variations and enhanced early flame development. With the longer spark durations of the capacitive system the lean limit was extended from λ = 1.65 to approximately λ = 1.75. (Less)

<div class="section abstract"><div class="htmlview paragraph">Achieving a robust ignition with minimal spark plug wear is challenging in heavy duty engines fueled with gaseous fuels like biogas and hydrogen. Thermal energy deposition from the spark to the gas was studied in a 10.9 milliliter custom-built spark calorimeter. An AC capacitive ignition system was used along with a dual-nickel standard J-gap spark plug and the influence of multiple physical and electrical parameters was investigated in an experimental design including five factors: spark plug center electrode diameter, electrode gap, glow current, glow duration, and gas density. The aim was to maximize energy transfer to the gas and reduce heat losses to the spark plug electrodes, thus extending spark plug service life and reducing the risk of pre-ignition in hydrogen engines caused by overheated electrodes. The results show that the electrode gap has the dominating influence on energy transfer to the gas. Both the gas density and the glow current contribute to increased energy deposition, but their effects strongly depend on the electrode gap. In contrast, glow duration and center electrode diameter showed negligible influence. Based on the findings, optimal ignition control strategies are proposed for biogas- and hydrogen-fueled spark-ignition internal combustion engines (SI-ICEs). The strategies vary with operating conditions throughout the spark plug service life.</div></div>

<div class="section abstract"><div class="htmlview paragraph">The paper presents novel studies on the impact of different ignition control parameters on combustion stability and spark plug wear. First, experimental results from a 32.4-liter biogas fueled large bore single cylinder spark ignition engine are discussed. Two different ignition systems were considered in the experiment: a DC inductive and an AC capacitive. The spark plugs used in the experiment were of dual-iridium standard J-gap design of different electrode gaps. Test results show the importance of different degrees of freedom to control a spark. A robust ignition is found to be achieved by using a very short spark duration, which in turn reduces total energy discharge at the gap. Further observations reveal that once a stable and self-propagating flame kernel is developed, it becomes independent of the spark energy further added to the gap. Finally, results from the spark plug wear tests using a pressurized rig chamber are discussed. It is found that an excessive spark energy discharge at the gap contributes to high erosion of spark plug electrodes, which is not desirable. However, spark energy is not the only factor affecting spark plug erosion. It is also the type of spark discharge (DC/AC) that governs the electrode wear over time. Therefore, the advantage of an AC spark discharge over a DC spark has been well established through the experimental results. The inherent property of an AC spark is found to be significantly slowing down electrode wear over time, hence increasing the service life of a spark plug.</div></div>

The operation of the internal combustion engine in areas of poor and rich mixture is characterized by a decrease in the efficiency of the catalytic converter and increase in the degree of wear of the system of elements fuel supply systems, ignition and antitoxic systems. Current trends of shifting the operation of the internal combustion engine to the area of poor mixtures. leads to increased emissions of NO and CO2, deterioration of the combustion process. The diagnostic parameters, which are free oxygen and the excess air coefficient, were theoretically determined and selected for the research. The regularity of the change in O2 at 20 % and 40 % of the throttle opening from the resistance of the exhaust tract and the spark plug gap with varying injection time duration has been established. Experimental control of the parameter l showed a trend of having a maximum in the zone of injection durations, and a gradual decrease when shifting to the zone of long injection durations to the limits of the efficiency of the internal combustion engine. An increase in the resistance of the exhaust tract leads to an equidistant shift of the characteristics l upwards into the zone of large values l while significantly reducing the range of the engine performance.

Flow dynamics near the spark plug gap have become more important to promote more stable lean/dilute combustion in internal combustion engines. One experimental technique for the measurement of instantaneous gaseous flow in an engine cylinder is particle image velocimetry (PIV). However, PIV measurement of the flow near solid objects is difficult because of the flare due to strong scattered light from the solid objects. Therefore, methods that use fluorescent particles (f-particles) have been proposed to reduce this undesirable effect. The mass production of inexpensive inorganic-based f-particles was previously proposed by one of the authors of this paper, assuming flow measurement in a firing engine. Furthermore, flow measurement near the spark plug gap was attempted using PIV with these f-particles, whereby the unsteady flow motion near the spark plug was successfully detected. However, the measurements were conducted under atmospheric conditions at room temperature. Therefore, as a next step, investigation of the effect of ambient pressure and temperature on the fluorescence intensity of the f-particles, is required to clarify the degree of oxygen quenching and temperature quenching of the f-particles. The effect of ambient pressure on fluorescent intensity was investigated fundamentally using a constant volume vessel. As a result, the intensity of fluorescence emitted from the f-particles was almost equal at pressures between 0.1 MPa and 2.0 MPa.

Gasoline spark ignition system in cars remains one of the main consumption of fuel in the world nowadays. During combustion process, spark plug is one important key features in a gasoline engine. The incompatibility of spark plug gap width and the fuel used causing backfire and knocking in the combustion engine. Thus, the spark plug gap was studied with focussing in controlling the combustion process to improve the performance of the engine. The main purpose of this research is to investigate the effect of spark plug air gap on flame development. The parameters studied in this research include spark plug air gap width (1.0 mm, 1.2 mm, 1.4 mm, 1.6 mm and 1.8 mm), injection pressure (0.3 MPa, 0.4 MPa, 0.5 MPa and 0.6 MPa) and flame characteristics such as flame front area and the flame intensity. The flame front area of different spark plug gap and injection pressure were investigated through Schlieren photography method. The Schlieren images taken were analysed with the time changes. The experiment results proved that the increase of spark plug gap width will led to better flame development in shorter time while increased the chance of misfire.

As the sparks produced by a conventional spark plug do not assure each time a complete combustion of the gasoline into the internal combustion engines, among different types of solutions given by worldwide researchers and car manufacturers (pulsed laser ignition, multi-ignition points systems, multi-electrodes spark-plugs etc.) we have proposed and tested a new type of ignition system that has as main element a double spark-plug. It can produce two quasi-simultaneous sparks having a cumulated length of over five times higher than the ones produced by a conventional spark plug. The power supply consist of an electronic ignition coil used on modern cars controlled by a microcontroller based unit that can provide different types of control pulses, with one or two pulses having adjustable width for each combustion cycle. The aim of this paper is to present a characterization of the high voltage discharges produced by the double spark plug, taking into account the electrical parameters such the discharge energy, current or breakdown voltage. The results are shown as a comparison with those obtained for a conventional ignition system. A short correlation between the electrical parameters and the plasma rotational temperature is also presented.

This study investigates the effect of ignition parameters on the cyclic dispersion and the specific fuel consumption of a carburetted single-cylinder engine. Ignition energy measurements were made on the low- and high-voltage sides of the ignition coil, and the performance was predicted satisfactorily by a simple model with passive elements. The spark energy was varied by changing the spark plug gap and the coil-on-time. The spark energy was measured in a special calorimeter: the aim was to find a correlation between engine performance and the spark energy measured by the calorimeter. The tests were conducted at part load and low speed with a weak mixture, as these conditions are known to give high levels of cyclic dispersion. The spark calorimeter showed a higher spark plug conversion efficiency for spark plugs with large gaps. However, the spark plug gap was found to be a more significant determinant of engine performance than the spark energy measured by the calorimeter. The experimental results are preceded by a review of ignition phenomena and their influence on combustion.

Multi-point ignition of air/fuel mixture by the initiated subcritical streamer discharge

<div class="section abstract"><div class="htmlview paragraph">In-cylinder spray imaging by Mie scattering has been taken with frame rates up to 27,000 fps, along with high speed video photography of chemiluminescence and soot thermal radiation. Spectroscopic measurements have confirmed the presence of OH*, CH* and C2* emissions lines, and their magnitude relative compared to soot radiation. Filtering for CH* has been used with both the high speed video and a Photo-Multiplier Tube (PMT). The PMT signals have been found to correlate with the rate of heat release derived from in-cylinder pressure measurements. A high power photographic strobe has been used to illuminate the fuel spray. Images show that the fuel spray can strike the ground strap of the spark plug, break up, and a fuel cloud then drifts over and under the strap through the spark plug gap. Tests have conducted at two different spark plug orientations using a single spark strategy. The images show interaction of a fuel jet with the earth electrode, stretching of the arc, variable location for the start of combustion and significant cycle-by-cycle variations with the same operating point leading: to normal combustion, slow combustion and misfiring cycles. The high speed photography confirms that liquid droplets exist in the spark plug gap at the 10 o'clock spark plug orientation but not at the 2 o'clock spark plug orientation.</div></div>

The paper presents the results of the experimental research on the combustion process inside the cylinder of a large piston radial aircraft engine with dual spark plug ignition. The tests were carried out on the ASz-62IR-16X radial engine equipped with a double, electronically controlled ignition system with two spark plugs in each cylinder. The constant engine speed tests allowed for comparing the combustion processes with ignition carried out with different ignition advance angle offset between both spark plugs. In the test, the ignition advance angle for one spark plug was changed while leaving the ignition advance angle for the other spark plug. The tests performed for two engine operating points were to change the angle of the front spark plug and the rear spark plug. The analyses were based on the recorded pressure signal from one of the engine cylinders. It has been shown that the ignition advance angle offset significantly affects the combustion process. The obtained results indicate the leading role of the rear spark plug in initiating the combustion process. When ignition is carried out with a steady rear spark plug advance angle, the combustion process practically does not change when the ignition advance angle of the front spark plug changes. However, changing the rear spark plug advance angle at a constant front spark plug ignition advance angle significantly changes the combustion process.

This report is a summary of the results of Phase 1 of this contract. The objective was to evaluate the potential of assist technologies for direct-injected alternative fuel engines vs. glow plug ignition assist. The goal was to demonstrate the feasibility of an ignition system life of 10,000 hours and a system cost of less than 50% of the glow plug system, while meeting or exceeding the engine thermal efficiency obtained with the glow plug system. There were three tasks in Phase 1. Under Task 1, a comprehensive review of feasible ignition options for DING engines was completed. The most promising options are: (1) AC and the ''SmartFire'' spark, which are both long-duration, low-power (LDLP) spark systems; (2) the short-duration, high-power (SDHP) spark system; (3) the micropilot injection ignition; and (4) the stratified charge plasma ignition. Efforts concentrated on investigating the AC spark, SmartFire spark, and short-duration/high-power spark systems. Using proprietary pricing information, the authors predicted that the commercial costs for the AC spark, the short-duration/high-power spark and SmartFire spark systems will be comparable (if not less) to the glow plug system. Task 2 involved designing and performing bench tests to determine the criteria for the ignition system and the prototype spark plug for Task 3. The two most important design criteria are the high voltage output requirement of the ignition system and the minimum electrical insulation requirement for the spark plug. Under Task 3, all the necessary hardware for the one-cylinder engine test was designed. The hardware includes modified 3126 cylinder heads, specially designed prototype spark plugs, ignition system electronics, and parts for the system installation. Two 3126 cylinder heads and the SmartFire ignition system were procured, and testing will begin in Phase 2 of this subcontract.

Hydrogen fuel is gaining particular attention in internal combustion engines. In addition to zero-carbon emissions, major advantages relate to its combustion characteristics, which allow a significant increase in thermal efficiency under ultra-lean operation and with very low NOx levels. The ignition system is one of the main technology enablers, as it determines the capability to control ultra-lean operations, avoid backfire phenomena, and/or reduce the risks of abnormal combustions. The latter results from hydrogen’s low ignition energy and it is associated with factors like high-temperature residuals, hot spots, and irregular spark plug discharge. The ACIS gen 2-Barrier Discharge Igniter excels in accelerating the initial flame growth speed by the generation of non-equilibrium low-temperature plasma, a strong ignition promoter for the combined action of kinetic and thermal effects. Moreover, its volumetric discharge facilitates combustion initiation on a wide region, in contrast to the localized ignition of traditional spark systems. In this work we present for the first time, to the best of our knowledge, experimental results showing the performance of a hydrogen engine with a low-temperature plasma discharge. Tests were conducted on a single-cylinder research engine, achieving ultra-lean conditions with cycle-to-cycle variability results below 2.5%. The analysis indicates that the H2-BDI combined solution is capable of accelerating the evolution of the flame front compared to traditional spark plugs, leading to a significant reduction in the cycle-to-cycle variability. A meticulous adjustment of the BDI control parameters further enhances igniter performance and contributes to a deeper understanding of the innovative approach proposed in this study.

[ES] En los últimos años, la investigación en motores se ha centrado principalmente en la reducción de emisiones contaminantes y en el aumento de la eficiencia. Muchos de los esfuerzos de investigación actuales en este campo están dirigidos a mejorar y desarrollar nuevas estrategias activas para la reducción de emisiones, en particular centradas en los nuevos conceptos de combustión y en la obtención de un mejor control sobre ella. Su desarrollo requiere la aplicación de nuevas herramientas experimentales y teóricas. Estas herramientas deberían permitir tanto la aplicación de nuevas estrategias activas de control de contaminantes como ampliar el conocimiento básico de los fundamentos de los procesos involucrados. En este contexto es donde se encuadra el objetivo de esta Tesis: el desarrollo y optimización de un nuevo sistema de encendido no intrusivo y modulable, que permitirá el control sobre el tiempo y la ubicación del punto de encendido. Dicho sistema se aplicará para el encendido de chorros Diesel de inyección directa. En particular, se pretende evidenciar cómo las condiciones locales al encendido pueden afectar al desarrollo de la combustión posterior. Para lograr este objetivo, el trabajo de investigación se ha dividido en dos bloques principales. El primero se centra en el desarrollo y la optimización del sistema de encendido. Aprovechando las posibilidades que ofrece el proceso de inducción de plasma con láser y, una vez seleccionado el mejor método de inducción para su aplicación en un entorno especifico como el de un motor, se ha llevado a cabo un proceso de optimización y validación del sistema. Tal proceso resulta de importancia básica en el desarrollo de esta investigación, ya que la aplicación de un sistema de encendido totalmente fiable resulta ser fundamental, tanto en términos de su posible aplicación para control de combustión como en términos de las posibilidades de estudios que pueda ofrecer. Al principio, a partir de un extenso estudio de la literatura sobre el proceso de inducción de plasma con láser, se han obtenido los parámetros fundamentales a tener en cuenta para la aplicación del sistema al encendido de chorros de combustible de inyección directa. A partir de estos parámetros, se ha diseñado un primer sistema de encendido. Luego su fiabilidad en la inducción de plasma ha sido estudiada experimentalmente en condiciones ambientales y de motor, aplicando una metodología de optimización desarrollada en este mismo trabajo experimental. Como resultado principal de este primer bloque de trabajo, se ha podido obtener un sistema de encendido por plasma inducido con láser completamente optimizado y fiable, así como un método novedoso para su validación y optimización. El segundo bloque de trabajo corresponde a la aplicación del sistema al encendido de un chorro Diesel de inyección directa en condiciones reales del motor. El objetivo de este bloque era lograr dos hitos principales: la determinación de las capacidades y los límites del sistema en su aplicación, y el desarrollo de un primer estudio experimental sobre la influencia de las condiciones locales de la zona de encendido sobre una combustión Diesel. Para lograrlo, primero se ha validado la capacidad de encendido del sistema bajo un conjunto adecuado de condiciones termodinámicas, previamente seleccionadas para mantener la máxima efectividad. Los resultados de este estudio, en comparación con los típicos parámetros de autoencendido en las mismas condiciones, han permitido demostrar la capacidad de encendido del sistema. Posteriormente, se ha llevado a cabo una variación paramétrica de tiempos y posiciones en las que inducir el plasma, con el fin de determinar el efecto de las condiciones locales sobre el desarrollo de la combustión Diesel. En este caso, al comparar los resultados obtenidos con los parámetros estándar de autoencendido, se han podido obtener tendencias interesantes, que subra