PIV Measurements of In-Cylinder Tumble Flow in a Motored Single Cylinder Optical Research Engine

Gomes, Carlos Alberto; Costa, Roberto Berlini Rodrigues da; Franco, Rafael Lara; Valle, Ramón Molina; Huebner, Rudolf

doi:10.4271/2015-36-0305

Cited by 12 publications

(2 citation statements)

References 25 publications

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“…The first trend could be associated with the tumble motion (vertical plane) and the selected injection mode (PFI). For the same cylinder head used in this work and similar crank angle speed, Gomes et al [40] measured Tumble ratios of 4.0 during intake and 1.5 during compression. Centered flames during late combustion are expected because it is the center of the optical window (see Figure 1b).…”

Section: Optical Investigationsmentioning

confidence: 93%

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Effect of Fuel and Air Dilution on Syngas Combustion in an Optical SI Engine

et al. 2019

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To mitigate the increasing concentration of carbon dioxide in the atmosphere, energy production processes must change from fossil to renewable resources. Bioenergy utilization from agricultural residues can be a step towards achieving this goal. Syngas (fuel obtained from biomass gasification) has been proved to have the potential of replacing fossil fuels in stationary internal combustion engines (ICEs). The processes associated with switching from traditional fuels to alternatives have always led to intense research efforts in order to have a broad understanding of the behavior of the engine in all operating conditions. In particular, attention needs to be focused on fuels containing relatively high concentrations of hydrogen, due to its faster propagation speed with respect to traditional fossil energy sources. Therefore, a combustion study was performed in a research optical SI engine, for a comparison between a well-established fuel such as methane (the main component of natural gas) and syngas. The main goal of this work is to study the effect of inert gases in the fuel mixture and that of air dilution during lean fuelling. Thus, two pure syngas blends (mixtures of CO and H2) and their respective diluted mixtures (CO and H2 with 50vol% of inert gases, CO2 and N2) were tested in several air-fuel ratios (stoichiometric to lean burn conditions). Initially, the combustion process was studied in detail by traditional thermodynamic analysis and then optical diagnostics were applied thanks to the optical access through the piston crown. Specifically, images were taken in the UV-visible spectrum of the entire cycle to follow the propagation of the flame front. The results show that hydrogen promotes flame propagation and reduces its distortion, as well as resulting in flames evolving closer to the spark plug. All syngas blends show a stable combustion process, even in conditions of high air and fuel dilution. In the leanest case, real syngas mixtures present a decrease in terms of performance due to significant reduction in volumetric efficiency. However, this condition strongly decreases pollutant emissions, with nitrogen oxide (NOx) concentrations almost negligible.

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Section: Optical Investigationsmentioning

confidence: 93%

“…For this type of combustion chamber geometries, the swirl motion (horizontal plane) is low. Huang et al [41] show that for a similar combustion chamber geometry the swirl ratio values are around 0.1 [40]. Therefore, another comparison between fuels was done with maximum vertical displacement (Figure 20b).…”

Section: Optical Investigationsmentioning

confidence: 97%