Extension of Operating Window for Modern Combustion Systems by High Performance Ignition

Brandt, Martin S.; Hettinger, Alexander; Schneider, Andreas; Senftleben, Hartwig; Skowronek, Tim

doi:10.1007/978-3-319-45504-4_2

Cited by 22 publications

(15 citation statements)

References 11 publications

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“…Typically, advanced ignition systems attempt to overcome the ignition limit by increasing either their output energy (e.g., dual-coil ignition [10,11], Controlled Electronic Ignition [12]) or the effectiveness of the spark-to-gas energy transfer (e.g. microwave-assisted spark ignition [13,14], corona ignition [15,16,17], nanosecond-pulsed transient-plasma ignition [18,19], breakdown ignition [4], laser ignition [20]).…”

Section: Ignition Limitsmentioning

confidence: 99%

“…The second was an IDI system that delivered 140 mJ. The third used a modified circuit to produce a tunable spark duration and thus tunable energy [12].…”

Section: Ignition Limitsmentioning

confidence: 99%

“…Controlled Electronic Ignition The third system was Bosch Controlled Electronic Ignition. The CEI discharge goes through the same breakdown, arc, and glow phases as any other spark-plug-based ignition system, but CEI uses a modified circuit producing an extended glow phase that is tunable in duration [12], as illustrated by the current-time cartoon in Figure 2. The current is nearly constant during the extended glow time and then decays in the normal way afterward.…”

Section: Conventional Ignition Systemsmentioning

confidence: 99%

“…The glow times reported here are the extended glow times, which exclude the natural decay and thus underestimate the total glow-phase. The voltage-time curve [12] is more structured than the current-time curve; the voltage is 37-45 kV during the breakdown phase but drops to ~1 kV during the arc phase, after which it fluctuates with an amplitude of ~1 kV throughout the remainder of the discharge. The energy delivered by CEI was claimed by the manufacturer to be 50-300 mJ, depending on the dwell and glow times, which were separately adjustable over 0.4-1.6 ms and 0.3-5.0 ms, respectively.…”

Section: Conventional Ignition Systemsmentioning

confidence: 99%

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Infrared Borescopic Evaluation of High-Energy and Long-Duration Ignition Systems for Lean/Dilute Combustion in Heavy-Duty Natural-Gas Engines

Mazacioglu¹,

Groß²,

Kern³

et al. 2018

SAE Technical Paper Series

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N atural gas (NG) is attractive for heavy-duty (HD) engines for reasons of cost stability, emissions, and fuel security. NG cannot be reliably compressionignited, but conventional gasoline ignition systems are not optimized for NG and are challenged to ignite mixtures that are lean or diluted with exhaust-gas recirculation (EGR). NG ignition is particularly challenging in large-bore engines, where completing combustion in the available time is more difficult. Using two high-speed infrared (IR) cameras with borescopic access to one cylinder of an HD NG engine, the effect of ignition system on the early flame-kernel development and cycle-to-cycle variability (CCV) was investigated. Imaging in the IR yielded strong signals from water emission lines, which located the flame front and burned-gas regions and obviated image intensifiers. A 9.7-liter, six-cylinder engine was modified to enable exhaust-gas recirculation and to provide optical access. Three ignition technologies were studied: a conventional system delivering 65 mJ of energy to each spark, a high-energy conventional system delivering 140 mJ, and a Bosch Controlled Electronic Ignition (CEI) system. CEI uses electronics to extend the ignition event, yielding sparks up to 5 ms in duration with up to 300 mJ of energy. Air/fuel equivalence ratios, λ, as high as 1.6 (with minimum EGR) and EGR fractions as high as 23% (stoichiometric) were tested; ignition delay, engine-out emissions, fuel consumption and image-derived parameters were compared. In most lean or dilute cases, the 140-mJ system yielded the lowest CCV. The imagery provided information about the early stages of ignition and combustion, where pressure measurements are not reliable. Image-based metrics also revealed that early flame kernels located further from the head yielded better combustion, showing that borescopic IR imaging can provide guidance for future engine design. INFRARED BORESCOPIC EVALUATION OF HIGH-ENERGY AND LONG-DURATION IGNITION SYSTEMS

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Section: Ignition Limitsmentioning

confidence: 99%

“…The second was an IDI system that delivered 140 mJ. The third used a modified circuit to produce a tunable spark duration and thus tunable energy [12].…”

Section: Ignition Limitsmentioning

confidence: 99%

Section: Conventional Ignition Systemsmentioning

confidence: 99%

Section: Conventional Ignition Systemsmentioning

confidence: 99%

See 2 more Smart Citations

Infrared Borescopic Evaluation of High-Energy and Long-Duration Ignition Systems for Lean/Dilute Combustion in Heavy-Duty Natural-Gas Engines

Mazacioglu¹,

Groß²,

Kern³

et al. 2018

SAE Technical Paper Series

View full text Add to dashboard Cite

show abstract

“…To aid further extension of the dilution tolerance of the engine, a Bosch Controlled Electronic Ignition (CEI) system [17], providing continuous ignition energy of up to 500mJ, was used. In the wider literature [3,4,5] and in addition to a supplementary in-house study [16], continuous ignition has been shown to reduce the ignition to 5% and 10% Mass Fraction Burned (MFB) durations compared to a "stock" ignition coil (circa 85mJ) and also an equivalent ignition system operating in high energy single strike (circa 140mJ) and multi-strike modes.…”

Section: Experimental Enginementioning

confidence: 99%

Effects of Valve Deactivation on Thermal Efficiency in a Direct Injection Spark Ignition Engine under Dilute Conditions

Roberts¹,

Kountouriotis²,

Okroj³

et al. 2018

SAE Technical Paper Series

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Reported in the current paper is a study into the cycle efficiency effects of utilising a complex valvetrain mechanism in order to generate variable in-cylinder charge motion and therefore alter the dilution tolerance of a Direct Injection Spark Ignition (DISI) engine. A Jaguar Land Rover Single Cylinder Research Engine (SCRE) was operated at a number of engine speeds and loads with the dilution fraction varied accordingly (excess air (lean), external Exhaust Gas Residuals (EGR) or some combination of both). For each engine speed, load and dilution fraction, the engine was operated with either both intake valves fully open-Dual Valve Actuation (DVA)-or one valve completely closed-Single Valve Actuation (SVA) mode. The engine was operated in DVA and SVA modes with EGR fractions up to 20% with the excess air dilution (Lambda) increased (to approximately 1.8) until combustion stability was duly compromised. At 1500 Revolutions Per Minute (RPM), 3.6bar and 7.9bar Gross Mean effective Pressure (GMEP), the dilution tolerance of the engine was significantly increased for a given combustion stability limit utilising SVA. This resulted in fuel consumption reductions of up to 3.8% and 3.1% respectively for these two engine speed and load conditions as a result of being able to operate the engine with more thermodynamically attractive mixtures when adopting SVA. At 2000RPM, 9.8bar GMEP, the dilution tolerance was only marginally increased which resulted in a fuel consumption reduction of 1.3% when adopting SVA over DVA (for the same reasons outlined above). Increased dilution tolerance in all cases was achieved as a result of significant enhancement in charge motion when adopting SVA. By enhancing the in-cylinder charge motion (confirmed using Computational Fluid Dynamics (CFD)), ignition to 10% Mass Fraction Burned (MFB) and 10-90% MFB durations for equivalent levels of dilution were significantly shorter when adopting SVA. This therefore allowed greater dilution tolerance (and ultimately an increase in the thermal efficiency of the working cycle) when adopting SVA over DVA without detrimental increases in the burn duration metrics that would ordinarily result in misfire and partial burn and a significant detriment to combustion stability. Conversely, for equivalent levels of dilution, there was little, if any difference in fuel consumption between DVA and SVA even though burn duration metrics were significantly shorter when adopting SVA over DVA. In combination with CFD, the polytropic coefficient of compression was calculated to be lower in all cases for SVA compared to DVA for a given level of dilution. This indicated greater heat transfer when adopting SVA over DVA for equivalent trapped mass (confirmed using CFD). As such, this detrimental increased heat transfer (again confirmed with CFD) attributed to the increased in-cylinder activity with SVA offset the favourably faster combustion; thus resulting in little, if any reduction in fuel consumption for equivalent levels of dilution when implementing SVA over DVA. This...

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Introduction

Maurya

2019

Mechanical Engineering Series

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Extension of Operating Window for Modern Combustion Systems by High Performance Ignition

Cited by 22 publications

References 11 publications

Infrared Borescopic Evaluation of High-Energy and Long-Duration Ignition Systems for Lean/Dilute Combustion in Heavy-Duty Natural-Gas Engines

Infrared Borescopic Evaluation of High-Energy and Long-Duration Ignition Systems for Lean/Dilute Combustion in Heavy-Duty Natural-Gas Engines

Effects of Valve Deactivation on Thermal Efficiency in a Direct Injection Spark Ignition Engine under Dilute Conditions

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