Gas Assisted Jet Ignition of Ultra-Lean LPG in a Spark Ignition Engine

Toulson, Elisa; Watson, Harry C.; Attard, William P.

doi:10.4271/2009-01-0506

Cited by 59 publications

(16 citation statements)

References 13 publications

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“…Prechamber combustion can be referred to as a "prechamber combustor" [7], "prechamber ignition" [3], "torch ignition" [8][9][10], "jet ignition" [11][12][13][14][15][16], "two-stage combustion" [17][18][19], and "scavenged prechamber" [2,20]. Results from these studies validate the advantages of the fuel-added prechamber for SI engines and confirm the lean-burning and fuel-saving efficiencies of prechambers with an additional fuel delivery nozzle.…”

Section: Introductionmentioning

confidence: 67%

A Charge Possibility of an Unfueled Prechamber and Its Fluctuating Phenomenon for the Spark Ignited Engine

2020

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The demand for internal combustion engines remains high for mobile power sources in all fields due to their low costs, running distance capacity, charging reliability, and heavy driving durability. However, air pollution, efficiency, and environmental factors make this more challenging. According to recent research, using a fueled prechamber can lead to lean combustion in the main chamber, resulting in increased efficiency, reduced fuel consumption, and reduced toxic emissions. However, difficulties in producing a fueled prechamber for commercial engines include mixture and soot formation problems in the limited space of the prechamber, and limited research on the charging possibility of the unfueled prechamber. A removable prechamber is advantageous for used vehicles because an engine redesign is not required. Therefore, we proposed to use an unfueled prechamber to enhance the lean burning efficiency of the spark ignited (SI) engine and explore the possibility of charging an unfueled, unscavenged prechamber with a fuel-rich mixture. Consequently, investigating the possibility of filling an unfueled prechamber with a fuel-rich mixture without additional fuel delivery or an air control system was the aim of this study. For this purpose, the charge flowrate of the centrally located unfueled prechamber is extensively investigated by using Computational Fluid Dynamics (CFD), through its design. As a result, a realizable charge flow was detected for the unfueled prechamber in two periods in the inlet and compression strokes. Most importantly, we found fluctuation phenomena in mass flow rates at the inlet stroke directing a charge flow of the richer mixture into an unfueled prechamber without additional systems. Moreover, keeping the charged rich mixture inside the prechamber during the compression stroke is as important as charging the prechamber with the fuel-rich mixture. The study will enable us to produce a removable prechamber to improve the combustion efficiency of port injected engines.

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Section: Introductionmentioning

confidence: 67%

A Charge Possibility of an Unfueled Prechamber and Its Fluctuating Phenomenon for the Spark Ignited Engine

2020

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“…Following the first hump, there is a transition point where the jet energy is dissipated, and burning of the bulk of the main chamber charge begins, causing the double hump, a characteristic commonly seen with TJI. 20,52,53 The higher rates of heat release seen with the 2-mm orifice, particularly in this second hump region, is attributable to the narrower initial jet with high penetration speed which leads to an increase in turbulent mixing and faster combustion during the latter stages of combustion.…”

Section: Resultsmentioning

confidence: 99%

Large eddy simulation of a homogeneously charged turbulent jet ignition system

Gholamisheeri

Givler

Toulson

2017

International Journal of Engine Research

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Transient jet ignition of a homogeneous methane air mixture in a turbulent jet ignition system is studied computationally using a large eddy simulation turbulence model. The jet discharges from a prechamber into a main combustion chamber via one or more orifice(s) and provides a distributed ignition source in turbulent jet ignition. The effect of orifice size and stoichiometry is studied numerically using the Converge computational fluid dynamics code. A reduced kinetic mechanism is used for combustion along with a Smagorinsky sub-model for turbulence modeling. The computed pressure traces are compared with experimental measurements through rapid compression machine tests. Computational fluid dynamics results are in acceptable agreement with the experimental data during compression and the early stage of combustion; however, an over-prediction of peak pressure was reported. Peak pressure error is in the range of 0.1%-4% for Reynolds-averaged Navier-Stokes simulation estimation compared to the experimental measurements. This error is a function of mixture stoichiometry and unburned gas temperature. The error calculation showed that with the large eddy simulation model, 1% and 12% improvements in peak pressure and burn rate estimations, respectively, were achieved compared to Reynolds-averaged Navier-Stokes results. The reduced large eddy simulation error relative to the Reynolds-averaged Navier-Stokes simulations were considered to be in the acceptable range; however, further improvements could be achieved through validation and testing of additional turbulence models. In addition, computational fluid dynamics temperature contours for various nozzle orifices and air-fuel ratios are compared to achieve deeper insight into the turbulent jet ignition combustion process in the rapid compression machine combustion cylinder. The numerical iso-surface temperature contours were obtained which enabled three-dimensional views of the flame propagation, the jet discharge, ignition and extinction events. The heat release process and regeneration of mid-range temperature iso-surfaces (1200 K) were not visible through the experimental images.

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“…In the 1990's, at the University of Melbourne, Watson et al [20][21][22] developed a prechamber ignition concept named Hydrogen Assisted Jet Ignition (HAJI). HAJI is similar to the other pre-chamber jet ignition concepts mentioned in this paper; the hardware consists of a small pre-chamber and orifices, spark plug, and pre-chamber direct injector.…”

Section: Introductionmentioning

confidence: 99%

“…As the name suggests, hydrogen is used as the pre-chamber fuel. Toulson et al performed a study of the HAJI system in a single cylinder research engine with Liquefied Petroleum Gas (LPG) as an alternative prechamber fuel, with the LPG having a composition of 95% propane and 5% butane [21]. Main chamber fuels tested were both LPG and gasoline.…”

Section: Introductionmentioning

confidence: 99%

A study of a turbulent jet ignition system fueled with iso-octane: Pressure trace analysis and combustion visualization

2017

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Turbulent Jet Ignition is an advanced pre-chamber ignition enhancement technique for spark ignition engines that uses a discharging jet of hot combusting gases to initiate main chamber combustion. The jet acts as a distributed ignition source, leading to fast burn rates and increased combustion stability. Experiments were performed in an optically accessible rapid compression machine using liquid iso-octane to study the effects of auxiliary fuel injection and ignition distribution due to nozzle geometry. A custom low-flow fuel injector was used to overcome previous limitations of using liquid fuel in the pre-chamber. Jet induced autoignition behavior was also studied in depth by considering high-speed images, pressure traces, and pressure derivative data.

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Gas Assisted Jet Ignition of Ultra-Lean LPG in a Spark Ignition Engine

Cited by 59 publications

References 13 publications

A Charge Possibility of an Unfueled Prechamber and Its Fluctuating Phenomenon for the Spark Ignited Engine

A Charge Possibility of an Unfueled Prechamber and Its Fluctuating Phenomenon for the Spark Ignited Engine

Large eddy simulation of a homogeneously charged turbulent jet ignition system

A study of a turbulent jet ignition system fueled with iso-octane: Pressure trace analysis and combustion visualization

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