Investigation of the Combustion Characteristics with Focus on Partially Premixed Combustion in a Heavy Duty Engine

Lewander, Magnus; Ekholm, Kent; Johansson, Bengt; Tunestål, Per; Milovanović, Nebojša; Keeler, Nathan; Harcombe, Tony; Bergstrand, Pär

doi:10.4271/2008-01-1658

Cited by 59 publications

(26 citation statements)

References 6 publications

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“…PPC is a promising combustion concept allowing to reduce both NO x and soot emissions while providing high combustion efficiency. By and large, the low NO x emissions result from the low combustion temperature, whereas the low soot emission is a result of increased premixing (with respect to conventional CI engines) [2][3][4][5][6]. However, many details of the incylinder phenomena are still to be explained and evaluated.…”

Section: Introductionmentioning

confidence: 99%

“…The broadband chemiluminescence did also correlate with the equivalence ratio quite well in both HCCI and PPC regimes, suggesting that the total emission in the spectral region of 330-400 nm can serve as a proxy of equivalence ratio and the rate of heat release. Regarding C 2 * chemiluminescence, we see two different chemical mechanisms for formation of C 2 * in the PPC regime: first during the early stage of combustion by the breakup of bigger molecules engines, relies on a relatively long ignition delay (ID) to achieve a partially premixed charge [1][2][3][4][5][6]. PPC is a promising combustion concept allowing to reduce both NO x and soot emissions while providing high combustion efficiency.…”

Section: Introductionmentioning

confidence: 99%

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The influence of charge stratification on the spectral signature of partially premixed combustion in a light-duty optical engine

et al. 2017

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The influence of charge stratification on the spectral signature of partially premixed combustion in a light-duty optical engine

et al. 2017

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“…Recently reviewed by Musculus et al [1] and investigated for applications in both light-duty [2][3][4][5][6] and heavy-duty [7][8][9][10] engines, LTC uses a combination of greater dilution and premixing of reactant mixtures compared to conventional diesel combustion [11] to suppress formation of NO x and soot. One common method of dilution is exhaust gas recirculation (EGR), which introduces high-heat-capacity species such as CO 2 and H 2 O into the cylinder, reduces the flame temperature, * Corresponding author.…”

Section: Introductionmentioning

confidence: 99%

Effect of post injections on mixture preparation and unburned hydrocarbon emissions in a heavy-duty diesel engine

O’Connor

Musculus

Pickett

2016

Combustion and Flame

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a b s t r a c tThis work explores the mechanisms by which a post injection can reduce unburned hydrocarbon (UHC) emissions in heavy-duty diesel engines operating at low-temperature combustion conditions. Post injections, small, close-coupled injections of fuel after the main injection, have been shown to reduce UHC in the authors' previous work. In this work, we analyze optical data from laser-induced fluorescence of both CH 2 O and OH and use chemical reactor modeling to better understand the mechanism by which post injections reduce UHC emissions. The results indicate that post-injection efficacy, or the extent to which a post injection reduces UHC emissions, is a strong function of the cylinder pressure variation during the post injection. However, the data and analysis indicate that the pressure and temperature rise from the post injection combustion cannot solely explain the UHC reduction measured by both engine-out and optical diagnostics. The fluid-mechanic, thermal, and chemical interaction of the post injection with the main-injection mixture is a key part of UHC reduction; the starting action of the post jet and the subsequent entrainment of surrounding gases are likely both important processes in reducing UHC with a post injection.

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“…Many studies report the transition to PPC and HCCI from CI combustion in metal CI engine [6,7]. Recently, in-cylinder diagnostics of combustion homogeneity and stratification of air/fuel mixture are studied in an optical CI engine.…”

Section: Introductionmentioning

confidence: 99%

Combustion Stratification for Naphtha from CI Combustion to PPC

Vallinayagam

Vedharaj

et al. 2017

SAE Technical Paper Series

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This study demonstrates the combustion stratification from conventional compression ignition (CI) combustion to partially premixed combustion (PPC). Experiments are performed in an optical CI engine at a speed of 1200 rpm for diesel and naphtha (RON = 46). The motored pressure at TDC is maintained at 35 bar and fuelMEP is kept constant at 5.1 bar to account for the difference in fuel properties between naphtha and diesel. Single injection strategy is employed and the fuel is injected at a pressure of 800 bar. Photron FASTCAM SA4 that captures in-cylinder combustion at the rate of 10000 frames per second is employed. The captured high speed video is processed to study the combustion homogeneity based on an algorithm reported in previous studies.Starting from late fuel injection timings, combustion stratification is investigated by advancing the fuel injection timings. For late start of injection (SOI), a direct link between SOI and combustion phasing is noticed. At early SOI, combustion phasing depends on both intake air temperature and SOI. In order to match the combustion phasing (CA50) of diesel, the intake air temperature is increased to 90°C for naphtha. The combustion stratification from CI to PPC is also investigated for various level of dilution by displacing oxygen with nitrogen in the intake. The start of combustion (SOC) was delayed with the increase in dilution and to compensate for this, the intake air temperature is increased. The mixture homogeneity is enhanced for higher dilution due to longer ignition delay. The results show that high speed image is initially blue and then turned yellow, indicating soot formation and oxidation. The luminosity of combustion images decreases with early SOI and increased dilution. The images are processed to generate the level of stratification based on the image intensity. The level of stratification is same for diesel and naphtha at various SOI. When O 2 concentration in the intake is decreased to 17.7% and 14.7%, stratification level is decreased. NO X emission for both diesel and naphtha show a decreasing trend from CI to PPC.Comparing diesel and naphtha, the soot emission is lower for naphtha. NO X and soot emissions at various SOI are correlated with high speed images of combustion to explain the combustion stratification.

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Investigation of the Combustion Characteristics with Focus on Partially Premixed Combustion in a Heavy Duty Engine

Cited by 59 publications

References 6 publications

The influence of charge stratification on the spectral signature of partially premixed combustion in a light-duty optical engine

The influence of charge stratification on the spectral signature of partially premixed combustion in a light-duty optical engine

Effect of post injections on mixture preparation and unburned hydrocarbon emissions in a heavy-duty diesel engine

Combustion Stratification for Naphtha from CI Combustion to PPC

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