Characterization of a Multi-Cylinder Torch Ignition System Operating with Homogenous Charge and Lean Mixture

Moreira, T. A. A.; Baêta, José Guilherme Coelho; Filho, Fernando Antônio Rodrigues; Barros, José Eduardo Mautone; Pujatti, Fabrício José Pacheco; Malle, R.

doi:10.4271/2014-36-0333

Cited by 9 publications

(8 citation statements)

References 7 publications

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“…Results showed a marked increase in the slope of the HRR curve [11,15] which leads to improved combustion and indicating efficiencies, allowing us to decrease the fuel consumption [11,13]. Benefits in terms of NOx [9,16], HC [9,11,17] and CO [12,13] were also highlighted. However, passive prechambers were found to be unstable in PFI fuel-lean engines [13].…”

Section: Introductionmentioning

confidence: 92%

“…In particular, passive prechambers, devoid of a dedicated injector, which are claimed to be well suited for 2S engines due to the low complexity and limited costs, have been widely studied in carburettor and PFI engines for automotive use [8][9][10][11][12][13][14]. Results showed a marked increase in the slope of the HRR curve [11,15] which leads to improved combustion and indicating efficiencies, allowing us to decrease the fuel consumption [11,13]. Benefits in terms of NOx [9,16], HC [9,11,17] and CO [12,13] were also highlighted.…”

Section: Introductionmentioning

confidence: 99%

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Jet ignition in small two-stroke engines: an experimental survey on benefits and challenges

et al. 2021

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Increasingly stringent policy on carbon dioxide have proved to be a severe constraint on the design of light two-stroke (2S) engines. The enhancement of efficiency is claimed to be the main target to make these devices compliant with future regulations. Low-Pressure Direct Injection (LPDI) was found to be effective in the reduction of fuel short circuit, thus improving efficiency and mitigating pollution. Innovative combustion technologies are required to exploit further the fuel potential. Jet Ignition (JI), i.e., ignition provided by means of hot turbulent jets, was found to improve the fuel ignition process, leading to a faster and more uniform combustion. Several benefits are shown in over forty years of Literature, from the higher performance to wider flammability limits. However, few studies have been performed on small 2S engines, for which only full-load data are available. This paper aims at experimentally evaluating benefits and challenges of adopting the JI technology on light 2S LPDI engines at both full- and low- load operation. Different configurations of passive prechambers have been investigated in terms of indicated cycle, brake efficiency and cycle-to-cycle variation. A sensitivity analysis on the spark timing was performed to fine-tune the combustion process. Results show the adequacy of the JI for use in devices operating close to full torque, like garden tools; however, issues related to the excessive amount of residual gas or to the rapid pressure decrease during the expansion phase were highlighted. Different solutions for solving these challenges are proposed.

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Section: Introductionmentioning

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Jet ignition in small two-stroke engines: an experimental survey on benefits and challenges

et al. 2021

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“…According to Wimmer and Lee [13], the use of homogeneous prechamber systems presents a significant reduction in nitrogen oxides (NO x ) and carbon monoxide (CO) emissions with an increase in unburned hydrocarbons (HC) emissions. Moreira [14] attribute the increase in HC emission to the increment in the area for heat transfer and to the geometric characteristics of the prechamber. However, several studies since the prechamber concept development have pointed out that small variations in its project, such as the prechamber volume, can largely impact on the combustion behavior and, consequently, in exhaust emissions [6].…”

Section: Introductionmentioning

confidence: 99%

“…Studies more focused on the prechamber volume in the engine combustion parameters have pointed out its direct impact on pressure and temperature peaks [14]. The reduction in prechamber volume decreases the ignition induction period and the initial torch jet velocity, both for homogeneous and stratified charge operation [19].…”

Section: Introductionmentioning

confidence: 99%

The influence of volume variation in a homogeneous prechamber ignition system in combustion characteristics and exhaust emissions

Sandoval

Álvarez

Roso

et al. 2020

J Braz. Soc. Mech. Sci. Eng.

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Research on prechamber ignition systems has become increasingly frequent as they promote significant reductions in engineout emissions with low cost of implementation. In these systems, the combustion starts in an auxiliary chamber and flows through the interconnecting holes, in form of jets, to the main chamber, where it ignites the air-fuel mixture contained therein. Besides the air-fuel ratio, the geometry of the prechamber presents fundamental parameters that influence combustion characteristics and, consequently, the exhaust emissions. This paper aims to evaluate the effects of prechamber volume variation in combustion and emissions of a commercial engine equipped with a homogeneous charge prechamber ignition system. For this, three volumes were considered in stationary tests of a multi-cylinder engine operating under stoichiometric conditions in 1500 rpm and 3.3 bar of IMEP. The results indicated that the increase in volume within the limits considered present increase in the energy released and, hence, in the burning speed, reducing the combustion duration. Comparing to the baseline spark plug system, the prechamber with 3.8% of the main combustion chamber volume presented the best configuration among the evaluated volumes, with an increase in the evolution of pressure traces and reductions in around 13% in unburned hydrocarbons (HC) and nitrogen oxides (NO x) engine-out emissions.

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“…Additionally, faster flame jets induced by higher pressure difference were claimed to reduce the main chamber combustion duration. Moreira et al [9] analysed an unscavenged prechamber in a four cylinder engine. The unscavenged prechamber system was reported to lead to increased engine efficiency, as well as reduced NO x emissions and IMEP covariance.…”

Section: Introductionmentioning

confidence: 99%

Optical investigation of prechamber combustion in an RCEM

Kotzagianni¹,

Kyrtatos²,

Boulouchos³

2019

Combustion Engines

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In this study, detailed investigations of scavenged prechamber engine combustion are performed experimentally in a Rapid Com-pression Expansion Machine (RCEM), which allows optical access into the main chamber. OH* chemiluminescence measurements combined with pressure measurements are used to study the effect of varying ignition timing on combustion and cycle-to-cycle varia-tions. The variation of ignition timing (pressure at ignition) showed an optimum ignition point for a given injection duration. Earlier ignition resulted in weaker but more reactive jets, coupled to increased cyclic variations. Later ignition did not significantly affect heat release rate, but increased cyclic variation.

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Characterization of a Multi-Cylinder Torch Ignition System Operating with Homogenous Charge and Lean Mixture

Cited by 9 publications

References 7 publications

Jet ignition in small two-stroke engines: an experimental survey on benefits and challenges

Jet ignition in small two-stroke engines: an experimental survey on benefits and challenges

The influence of volume variation in a homogeneous prechamber ignition system in combustion characteristics and exhaust emissions

Optical investigation of prechamber combustion in an RCEM

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