The Application of Lag-Process in Prechamber Engines

Gussak, L. A.; Karpov, V. P.; Tikhonov, Yu. V.

doi:10.4271/790692

Cited by 124 publications

(48 citation statements)

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“…This has necessitated the development of higherenergy ignition sources [7,8]. A pre-chamber combustor application is one such technology, having been researched extensively [9,10,11,12,13]. SI engines that utilize prechambers generally retain the spark plug but relocate it to the pre-chamber and repurpose it as the ignition source for the…”

Section: Introductionmentioning

confidence: 99%

Methodology for Combustion Analysis of a Spark Ignition Engine Incorporating a Pre-Chamber Combustor

Bunce

Blaxill

2014

SAE Technical Paper Series

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With an increasing global awareness of the need to conserve fuel resources and reduce carbon dioxide emissions, the automotive sector has been seeking gains in engine efficiency. One such method for achieving these gains on a spark ignition (SI) engine platform is through lean burn operation. Ultra-lean operation (λ>2) has demonstrated the ability to increase thermal efficiency and significantly reduce emissions of nitrogen oxides (NO x ) due primarily to lower mean gas temperatures. Turbulent Jet Ignition (TJI), a pre-chamberbased combustion system, is a technology that enables ultra-lean operation. TJI is also an effective knock mitigation system due to the distributed nature of main chamber ignition, resulting in rapid burn rates.Pre-chamber combustors such as that utilized in TJI have been studied extensively for decades, but the interaction of the combustion events between the two chambers is not well understood. Additionally, current in-cylinder pressure transducer-based combustion analysis is limited in its effectiveness at capturing TJI combustion characteristics, particularly start of combustion (SOC) in the main chamber. This can lead to misleading heat release results and incomplete understanding of ignition and chamber interaction. This study analyzes the limitations of current combustion analysis techniques to characterize TJI and proposes a new methodology for combustion analysis.An optical engine is used to qualitatively assess pre-chamber jet formation and the subsequent main chamber ignition events. This data is synthesized with that of a single cylinder metal engine counterpart providing empirical heat release information. Utilizing high speed pressure transducers in both pre-chamber and main chamber, the validity of heat release data is explored within the context of the optically observed combustion process. A computational fluid dynamics (CFD) model is employed as an explanatory tool for the pre-chamber combustion event and the gas exchange process between the chambers. Informed by qualitative optical engine data, empirical heat release data, and CFD, this study seeks to produce a new methodology for combustion analysis that is applicable not only to TJI but to most pre-chamber-based SI combustion systems. Further accurate understanding of the interaction of the combustion events between the chambers and the gas exchange process can lead to optimum prechamber design and operation, and enable system scalability.

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Section: Introductionmentioning

confidence: 99%

Methodology for Combustion Analysis of a Spark Ignition Engine Incorporating a Pre-Chamber Combustor

Bunce

Blaxill

2014

SAE Technical Paper Series

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“…This concept was further developed by Gussak. By employing this concept, the first jet ignition engine under the name of LAG was designed by Gussak [18,19]. The LAG system is equipped with a cam-actuated injector.…”

Section: Introductionmentioning

confidence: 99%

Experimental and Numerical Study of Jet Controlled Compression Ignition on Combustion Phasing Control in Diesel Premixed Compression Ignition Systems

et al. 2014

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Abstract:In order to directly control the premixed combustion phasing, a Jet Controlled Compression Ignition (JCCI) for diesel premixed compression ignition systems is investigated. Experiments were conducted on a single cylinder natural aspirated diesel engine without EGR at 3000 rpm. Numerical models were validated by load sweep experiments at fixed spark timing. Detailed combustion characteristics were analyzed based on the BMEP of 2.18 bar. The simulation results showed that the high temperature jets of reacting active radical species issued from the ignition chamber played an important role on the onset of combustion in the JCCI system. The combustion of diesel pre-mixtures was initiated rapidly by the combustion products issued from the ignition chamber. Moreover, the flame propagation was not obvious, similar to that in Pre-mixed Charge Compression Ignition (PCCI). Consequently, spark timing sweep experiments were conducted. The results showed a good linear relationship between spark timing in the ignition chamber and CA10 and CA50, which indicated the ability for direct combustion phasing control in diesel PCCI. The NO x and soot emissions gradually changed with the decrease of spark advance angle. The maximum reduction of NO x and soot were both over 90%, and HC and CO emissions were increased.

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“…The demonstrated capability of these enhanced ignition systems to promote fast combustion rates in gasoline engines indicate their potentiality in reducing the octane requirement when they are properly Engines of this kind are natural candidates for the application of an enhanced ignition system, such as the LAG process of Gussak (34,35,36) where, instead of a turbulent torch issuing from the prechamber, the flame is intentionally extinguished by the use of a jet with a sufficiently strong turbulent shear to break it apart. Thus the main charge in the cylinder is provided only with 'combustion products, seeding it with active radicals that are capable of initiating combustion simultaneously at many points.…”

Section: Homogeneous Lean Chargementioning

confidence: 99%

“…upon the use of an appropriate enhanced ignition system. This might be attained either in the form of a LAG type prechamber, an advanced version of a divided chamber stratified charge engine described in the next section (34,35,36) or in the form of plasma jet igniters {11,12,37,38,39~40).…”

Section: Homogeneous Lean Chargementioning

confidence: 99%