The Effects of Charge Dilution on Combustion and Its Improvement-Flame Photograph Study

Nakanishi, Kenji; Hirano, Tomoyuki; Inoue, Toshihiko; Ohigashi, Shunichi

doi:10.4271/750054

Cited by 14 publications

(6 citation statements)

References 13 publications

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“…Curiously , a similar art i cle had been published two years earlier in English . The July article ) did not reference the March 1979 combustion bomb study ) but mentioned the 1975 EGR study (Nakanishi et al . 1975) and the 1971 diesel swirl study .…”

Section: 1 Swirl Research At Toyotamentioning

confidence: 99%

Japanese industrial research on lean combustion: A case study: International Research Monitoring Program

Hane¹,

Hutchinson²

1987

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In recent years, Japanese automakers have introduced a number of successful lean-combustion engines. These engines, in addition to the general expertise in building small cars, have made the Japanese automobiles into the gas mileage champions of the U.S. market. The lean-combustion engines also provide very satisfactory performance and acceptable emissions. United States automakers and research managers, who were probably better informed about leancombustion than the Japanese were, actively investigated lean-combustion but did not develop an engine. This report examines the basis for the Japanese innovations, the research that took the Japanese past the U.S. state of the art to permit engine development. A preliminary review of recent {1980s) Japanese literature did not turn up strong evidence of new research activity in the lean-combustion area, but did provide background on new engines developed by several major manufacturers. Developments by the most important automaker in Japan, the Toyota Motor Company, were then chosen for a case study. The study was conducted solely through the Japanese and U.S. published literature, with emphasis on early research conducted in the 1970s. Particular attention was paid to combustion chamber research, notably work which addressed the effects of turbulence and swirl and of prechamber combustion. All these techniques are used in Toyota's lean-combustion engines. References to early research conducted by Toyota engineers show a heavy reliance on information provided by previous work in the United States. This reliance appears to be characteristic of all Japanese work at the time of lean combustion in automobile engines. Rather than begin with the concept of lean combustion and proceed through stages of research that eventually led to engine designs, Japanese researchers apparently evaluated the more promising options reported in the international literature and then began developmental work on the selected options. By tracing subsequent publications from particular research and development (R&D) groups, it is possible to view the development of various leancombustion engine components. In the case of Toyota's prechamber combustion i i i design, the turbulence generator pot (TGP), the evolution of the design and changes to optimize performance and emissions levels can be seen in the Japanese literature. Even more clearly traceable are the stages that led to Toyota's development and selection of a helical intake port and a swirl control valve (SCV) for swirl generation. This arrangement was used in both the central injection engine and the Toyota lean-combustion system that were described in engine announcements published in 1984 (Shiozawa et al. 1984, Matsushita et al. 1984, Takeda et al. 1984). Despite the successful results, Toyota's research typically involved little more than standard engine tests, Schlieren photography, and some hotwire anemometry. More fundamental research, resembling that supported by the U.S. Department of Energy, did not begin to occur systematically un...

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Section: 1 Swirl Research At Toyotamentioning

confidence: 99%

Japanese industrial research on lean combustion: A case study: International Research Monitoring Program

Hane¹,

Hutchinson²

1987

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“…Conventional SI combustion is generally understood as having four primary stages, as thoroughly documented and analyzed by many authors (Rassweiler & Withrow, 1935) (Rassweiler & Withrow, 1938) (Nakanishi, Hirano, Inoue, & Ohigashi, 1975) (Nakamura, et al, 1978) (zur Loye & Bracco, 1987 (Bozza, Gimelli, Merola, & Vaglieco, 2005) and subsequently consolidated by (Heywood, 1988) and others. It must be recognized that the body of knowledge necessary to draw our current understanding of these processes is much more vast than can be cited here, and the specific references presented are ones that the author found particularly helpful.…”

Section: Spark-ignited Combustion Backgroundmentioning

confidence: 99%

“…Too much mixture motion can work to quench the flame kernel, as not enough energy is released to surpass the activation energy of large masses of combustible mixture that get forced into the kernel (Nakamura, et al, 1978). The flame kernel and early development tends to be the stage of combustion responsible for most of the natural cycle-to-cycle variation in individual combustion events, as small differences in flow structure, temperature, and mixture concentration around the spark plug can have large effects on the rate at which the kernel grows (Nakanishi, Hirano, Inoue, & Ohigashi, 1975). Subsequently, these differences carry through to the rest of the combustion event, especially once the piston reverses direction and begins expanding the mixture, cooling the bulk temperature.…”

Section: Spark-ignited Combustion Backgroundmentioning

confidence: 99%

“…The flame is generally strong enough at this point that it is unlikely to be overwhelmed by in-cylinder gas motion, and has grown to the point where heat losses to the spark plug and cylinder head represent a very small fraction of the energy released by combustion. It is possible therefore for increased in-cylinder flow to delay early spark kernel development stage, yet speed the laminar and subsequent stages for a net reduction in combustion duration, especially during the period between 10% and 90% MFB (Nakanishi, Hirano, Inoue, & Ohigashi, 1975).…”

Section: Spark-ignited Combustion Backgroundmentioning

confidence: 99%

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Analytical and Experimental Investigation of Temperature-Swing Insulation on Engine Performance

Andruskiewicz¹

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ResumenLos materiales aislantes han sido investigados a fondo por sus posibles mejoras en la eficiencia térmica de los motores de combustión interna alternativos. Estas mejoras se ven reflejadas tanto directamente en el trabajo indicado como indirectamente a través de la reducción del sistema de refrigeración del propio motor. Diferentes estudios, tanto experimentales como analíticos, han mostrado la reducción en la transferencia de calor a través de las paredes de la cámara de combustión mediante la utilización de estos materiales. Sin embargo, demostrar la conversión de la energía térmica adicional en trabajo indicado ha resultado más difícil. En ciertos estudios se pudieron obtener mejoras en el trabajo indicado durante la carrera de expansión, pero éstas fueron reducidas debido a un menor rendimiento volumétrico debido al calentamiento de la carga durante el proceso de admisión y un mayor trabajo en la carrera de compresión. Típicamente, las únicas mejoras en el trabajo al freno provendrían de la reducción de pérdidas por bombeo en los motores turboalimentados, o de la extracción de la energía adicional de los gases de escape a través de turbinas.El concepto de los materiales con oscilación de la temperatura durante el ciclo motor intenta aprovechar los beneficios del aislamiento durante los procesos de combustión y expansión, mitigando las perdidas por el incremento de la temperatura de las paredes durante la admisión y la compresión. La combinación de baja capacidad calorífica y baja conductividad térmica permitiría que la temperatura de la superficie de la cámara de combustión respondiera rápidamente a la temperatura del gas durante el proceso de combustión. Las temperaturas de la superficie son capaces de aumentar en respuesta al pico de flujo de calor, minimizando así la diferencia de temperatura entre el gas y la pared en la carrera de expansión cuando es posible la mayor conversión de energía térmica en trabajo mecánico. La combinación de baja capacidad calorífica y conductividad térmica es también esencial para permitir este aumento de temperatura durante la combustión y para permitir que la superficie se enfríe durante la expansión y el escape para no perjudicar así el rendimiento volumétrico del motor durante la carrera de admisión y minimizar el trabajo de compresión realizado en el siguiente ciclo.En esta tesis se han desarrollado modelos térmicos y termodinámicos para predecir los efectos de las propiedades de los materiales en las paredes y caracterizar los efectos de la transferencia de calor en diferentes partes del ciclo sobre el trabajo indicado, el rendimiento volumétrico, la energía en los gases de escape y las temperaturas del gas para un motor de combustión interna alternativo. También se ha evaluado el impacto del uso de estos materiales en el knock en motores de combustión de encendido provocado, ya que los estudios experimentales de esta tesis se realizaron en un motor de estas características.Durante la investigación se evaluaron materiales aislantes convencionales para comprender e...

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“…Post 1945 work on SI engines, an engine design incorporating a large quartz head window similar to that used by Rassweiler and Withrow [71] was employed by Nakanishi, et.al [72].…”

Section: Optical-access Engines For Combustion Studiesmentioning

confidence: 99%

Investigation of Combustion Phenomena in a Single-Cylinder Spark-Ignited Natural Gas Engine with Optical Access

Padmanaban¹

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More demanding efficiency and emissions standards for internal combustion (IC) engines require novel combustion strategies, alternative fuels, and improved after-treatment systems. However, their development depends on improved understanding of in-cylinder processes. For example, the lower efficiency of conventional spark-ignited (SI) natural-gas (NG) engines reduces their utilization in the transportation sector. Single-cylinder optical-access research engines allow the use of non-intrusive visualization techniques that study in-cylinder flow, fuel-oxidizer mixing, and combustion and emissions phenomena under conditions representative of production engines. These visualization techniques can provide qualitative and quantitative answers to fundamental combustion-phenomena questions such as the effects of engine design, operating conditions, fuel composition, fuel delivery strategy, and ignition techniques. The thesis is divided in two main parts. The first part focuses on the setup of a single-cylinder research engine with optical access including the design of its control system and the acquisition of in-cylinder pressure data and high-speed combustion images. The second part focuses on measurements of the turbulent flame speed using the high-speed combustion images. Crank-angle-resolved images of methane combustion were taken with a high-speed CMOS camera at a rate of 15,000 Hz. The optical engine was operated in a skip-firing mode (one fired cycle followed by 5 motored cycles) at 900 RPM and a load of 5.93 bar IMEP. The images show that flow turbulence and flame stretch resulted in flame velocities several order of magnitude higher compared to the laminar flame velocity. In addition, both in-cylinder pressure and optical data were used to determine the cycle-to cycle variability of the combustion phenomena. iii Dedication This thesis is dedicated to my beloved parents, Dr.Padmanaban, and Beena Padmanaban First and foremost, I would like to thank my research advisor Dr. Cosmin Dumitrescu for his support, knowledge and all the friendship he shared with me right from the beginning. Everything he taught me both, in academics and building me as a person will surely stay with me and help me progress in my future career. His perseverance in work have always strongly motivated me to put in a lot of efforts and set an example to my colleagues in the laboratory. I am very grateful to him for teaching me the difference between a scientific and an engineering work, helping me start transforming into a good researcher. On a lighter note, I am very thankful to him for having funded me three long semesters in my master's study. I would like to express my gratitude to Dan Carder for having initially hired me to the CAFEE, and help me settle down to work with optical engines research project. My heartfelt thanks are due to my committee member Dr. Arvind Thiruvengadam for having been a good friend and a wonderful source of inspiration. With his stature and knowledge, nobody I could think of to have been this modest, helpful and...

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The Effects of Charge Dilution on Combustion and Its Improvement-Flame Photograph Study

Cited by 14 publications

References 13 publications

Japanese industrial research on lean combustion: A case study: International Research Monitoring Program

Japanese industrial research on lean combustion: A case study: International Research Monitoring Program

Analytical and Experimental Investigation of Temperature-Swing Insulation on Engine Performance

Investigation of Combustion Phenomena in a Single-Cylinder Spark-Ignited Natural Gas Engine with Optical Access

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