Sub-200 g/kWh BSFC on a Light Duty Gasoline Engine

Bunce, Michael; Blaxill, Hugh

doi:10.4271/2016-01-0709

Cited by 40 publications

(23 citation statements)

References 18 publications

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“…It shows also the specific fuel consumption, converted to the energy-equivalent consumption of pure methane. The indicated efficiency peaks at around 50% (to be compared with 48.5% of Yin et al 57 ), and the brake thermal efficiency peaks at levels above 45% (to be compared with 41% of Bunce and Blaxill 23 ). The region with brake thermal efficiencies of more than 40% is very wide.…”

Section: Resultsmentioning

confidence: 98%

“…19–22 Literature also states that NO x is lower with a smaller prechamber and increased orifices, lean limit is higher with a larger prechamber and ignition delay and burn duration are shorter with larger prechamber and smaller orifices. 23,24…”

Section: Introductionmentioning

confidence: 99%

“…25,26 Prechamber systems have also found their way to high-performance race engines 27,28 and recently gained increasing interest in the research and technology community in terms of numerical modeling in different fidelity levels, 29–35 in fundamental experiments 36–39 or in the implementation to engines. 23,27,40,41…”

Section: Introductionmentioning

confidence: 99%

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Efficient light-duty engine using turbulent jet ignition of lean methane mixtures

Soltic

Hilfiker

Hänggi

2019

International Journal of Engine Research

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Diesel engines use diffusion-controlled combustion of a high-reactivity fuel and offer high efficiencies because they combine lean combustion with a high compression ratio. For low-reactivity fuels such as gasoline or natural gas, premixed combustion is used, which leads to lower efficiency levels as usually stoichiometric combustion is combined with lower compression ratios. Trying to apply diesel-like process parameters to low-reactivity fuels inevitably leads to problems with classical spark ignition systems as they are not able to establish robust flame propagation for such hard-to-ignite conditions. One possibility to enable fast combustion for diluted mixtures at high pressure levels is to establish ignition in a prechamber and ignite the charge of the main combustion chamber using the turbulent jets exiting the prechamber. In this study, the experimental results of a prechamber-equipped four-cylinder natural gas engine with 2 L displacement are discussed in detail. In the majority of the engine map, auxiliary fueling is used in the prechamber and a global air–fuel equivalence ratio λ is set to 1.7. At full load, a λ of 1.5 is applied without auxiliary prechamber fueling. The experiments show that such a setup is able to achieve brake efficiency levels of above 45% while maintaining peak brake mean effective pressure levels above 20 bar. At high load conditions, cylinder pressure levels at ignition timing achieve more than 80 bar and cylinder peak pressures of around 180 bars occur. The technology proved to enable robust and very fast combustion at comparably low NOx levels. A remaining challenge for the on-road use of such a technology is the reduction of the methane emissions at lean conditions.

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Section: Resultsmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

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Efficient light-duty engine using turbulent jet ignition of lean methane mixtures

Soltic

Hilfiker

Hänggi

2019

International Journal of Engine Research

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“…This desire is manifested in both market and regulatory demands. A method being increasingly explored to accomplish this goal is gasoline lean combustion [1][2][3][4][5]. Homogeneous lean combustion (1 < λ < ~1.6) in modern SI engines has been proven to increase thermal efficiency.…”

Section: Introductionmentioning

confidence: 99%

The use of active jet ignition to overcome traditional challenges of pre-chamber combustors under low load conditions

Bunce

Cairns

Blaxill³

2020

International Journal of Engine Research

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The need for advanced combustion technologies for use in future highly efficient powertrains in the automotive sector is well understood. Pre-chamber combustors, a technology with numerous historic examples, are fast becoming a major area of research once again. Pre-chambers are proportionally small partially enclosed chambers where combustion of a small quantity of fuel and air initiates before transferring to the main cylinder and, in spark ignition applications, subsequently igniting the bulk of the fuel and air. Pre-chambers effectively cascade two combustion events in order to increase the ignition energy present in the main combustion event, thereby enabling stable combustion of difficult-to-ignite main chamber mixtures, such as those with high levels of dilution. A traditional weakness of the subset of pre-chamber concepts known as jet igniters is poor low load engine performance. Combustion stability challenges and insufficient spark retard authority under heavily throttled conditions have limited the prospects of commercial implementation of jet ignition in modern engines. This study seeks to evaluate the root cause of these limitations and propose practical solutions that leverage the inherent flexibility of auxiliary fueled (active) jet ignition. Results of these experiments demonstrate the ability of a jet ignition engine to achieve idle and catalyst heating performance consistent with that of modern SI engines, thereby reducing the barriers to commercial implementation.

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“…Generally, this is done to provide a richer, more easily ignitable and energy dense mixture around the spark plug at the time of ignition while maintaining an overall lean mixture in the rest of the combustion chamber for improved fuel efficiency through a reduction in intake throttling and compression/expansion gas properties. This can be achieved through precise control of direct-fuel-injection and fuel spray targeting (Zhao, 2002) (Ando, 2009) (Fansler, 2015), or through separate fuel and air mixing channels within a pre-chamber such as the Honda CVCC design and the Mahle Jet Ignition concept (Bunce & Blaxill, 2016), among others. This body of work will focus on homogeneous SI combustion, achieved through direct injection coinciding with the intake stroke during the period of fastest piston motion.…”

Section: Spark-ignited Combustion Backgroundmentioning

confidence: 99%

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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Sub-200 g/kWh BSFC on a Light Duty Gasoline Engine

Cited by 40 publications

References 18 publications

Efficient light-duty engine using turbulent jet ignition of lean methane mixtures

Efficient light-duty engine using turbulent jet ignition of lean methane mixtures

The use of active jet ignition to overcome traditional challenges of pre-chamber combustors under low load conditions

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

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