Optical Engines as Representative Tools in the Development of New Combustion Engine Concepts

Kashdan, Julian T.; Thirouard, Benoist

doi:10.2516/ogst/2011134

Cited by 16 publications

(7 citation statements)

References 19 publications

(38 reference statements)

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“…Similar comparisons have already been made between a light duty truck engine with full optical access based on the Bowditch principle and the corresponding thermodynamic engine in Refs. [24][25][26] However, no corresponding comparison has been conducted for the larger engine size examined in this study. Yet, differences in load compatibility, wall temperatures and, in turn, emissions have been found.…”

Section: Summary and Discussionmentioning

confidence: 99%

Experimental comparison between an optical and an all-metal large bore engine

Karmann

Eicheldinger

Prager

et al. 2022

International Journal of Engine Research

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Rising engine efficiency, increasingly stringent exhaust limits, and the use of synthetic and renewable fuels are all factors that demand a deeper knowledge of the combustion process. State-of-the-art investigations employ optical and laser-optical measurement techniques that rely on having optical access to the engine. In this paper, a new endoscopic system that provides full optical access to a high-speed large-bore engine is compared by thermodynamic experimentation to the equivalent all-metal engine. This comparison provides an insight into the altered combustion behavior resulting from modifying the engine to accommodate the optical elements. The successfully realized concept consists of two individually usable access points integrated in an engine with a bore of 170 mm and a stroke of 210 mm. The lateral endoscopic access is designed for full-load operating conditions and provides the best comparability to an all-metal engine. It is compared directly to the all-metal engine in the present investigations. Despite the changes in engine-out emissions from the optical engine, the experimental results display relatively equal combustion behavior in both setups. The lateral endoscopic access is then extended by adding a fisheye endoscope in place of one exhaust valve. This setup is compared to findings obtained with the endoscopic lateral access. The investigations reveal further deviations of the combustion process due to the more extensive modifications needed to fit the fisheye endoscope to the cylinder head. Nevertheless, the results display an overall good level of comparability of the combustion behaviors in these setups and, in turn, of the validity of further fundamental experiments based on the optical engine.

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Section: Summary and Discussionmentioning

confidence: 99%

Experimental comparison between an optical and an all-metal large bore engine

Karmann

Eicheldinger

Prager

et al. 2022

International Journal of Engine Research

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“…As reported by a recent study, 12 there can be significant difference in the optical engine and a metal engine in fuel mixing and combustion, and emissions formation when results were compared between these two types of engines due to different materials on the combustion chamber wall heat transfer characteristics. Thus, it is preferable that both thermodynamic engine experiments and in-cylinder studies are performed in the same engine with minimum change, as it is the case of the present study.…”

Section: Introductionmentioning

confidence: 91%

Optical study of gasoline substitution ratio and diesel injection strategy effects on dual-fuel combustion

Mirmohammadsadeghi

Zhao

Itô

2019

Proceedings of the Institution of Mechanical Engineers, Part D:

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Ever growing population and increased vehicles have resulted in higher atmospheric concentration of the greenhouse gases, such as carbon dioxide and methane, thus increasing our planet's average temperature leading to irreversible climate changes, which has led to increasingly demanding and more strict legislations on pollutant emission and CO2, as well as fuel economy targets for the automotive industry. As a result, a great deal of efforts and resources has been spent on the research and development of high efficiency and low emission engines for automotive applications in the attempt to reduce GHG emissions and levels of nitrogen oxides and soot emissions, which affect the air quality.This research has developed strategies to investigate the combustion characteristics, engine performance, and exhaust emission of diesel-gasoline dual-fuel operation in a Ricardo Hydra single cylinder optical engine running at 1200 rpm, equipped with a high pressure common rail injection system for diesel fuel delivery, and a port fuel injection system, designed and manufactured by the author, for gasoline fuel delivery, in order to allow for dual-fuel operations. In-cylinder pressure measurement is used for calculating all engine parameters, heat release rate, and efficiency. In addition to the thermodynamic analysis of the combustion parameters, high speed imaging of spray and combustion chemiluminescence was used for the optical analysis of the effect of the above-mentioned parameters on autoignition and combustion processes.Effects of different substitution ratios and diesel injection strategies at low engine loads were studied when the total fuel energy was kept constant. The three main substitution ratios used in this study include 45%, 60%, and 75%, which also indicates the amount of fuel energy from port-injected gasoline, where the rest is provided by the direct injection of diesel.Depending on the testing conditions, such as injection strategy and intake conditions, some dual-fuel operations were able to deliver high efficiency and improved emissions compared to that of a pure diesel engine operation, with the diesel-gasoline operation offering more consistency in improved thermal efficiency. The optical analysis of the combustion illustrates the main difference in the flame propagation, distribution and quality for each substitution percentage, as well as the condition under examination. It was observed that combustions with higher concentration of diesel fuel having more diffusion like combustion, especially with diesel injection timings closer to the top dead centre, where there is less time for the two fuel and air to properly mix before combustion occurs, resulting in higher temperature and levels of NOx due to the pockets of high diesel concentrations within the combustion chamber, whereas higher concentration of gasoline, especially at earlier diesel injection timings, resulted in more homogenous fuel mixture, and thus lower combustion temperatures. In other words, When the gasoline substitution ratio is ...

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“…However, the large-area optical accesses exhibit altered heat transfer compared to real engines, resulting in higher surface temperatures 18 as well as differences in the in-cylinder pressure traces during combustion and the formation of pollutant emissions. 19 Since the formation of fuel films and hence soot depends on surface temperature and heat transfer, full-metal engines with minimally-invasive optical accesses are better suited for investigating soot formation.…”

Section: Introductionmentioning

confidence: 99%

Investigation of in-cylinder soot formation in a DISI engine during transient operation by simultaneous endoscopic PIV and flame imaging

Fach

Rödel

Schorr

et al. 2022

International Journal of Engine Research

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A single-cylinder full-metal engine with a real combustion chamber geometry was used to investigate particulate number emissions resulting from transient engine operation. The formation of particulate number emissions depends on mixture formation influenced by the in-cylinder flow and injection, and the formation of fuel films on the in-cylinder walls. For the investigation of this multi-parameter process, simultaneous endoscopic PIV and combustion visualization were applied. Hence, the measurement techniques allowed the investigation of in-cylinder flow, flame propagation, and soot formation. The test rig was modified to apply a generic load step and a realistic tip-in with Miller cycle. The reproducibility of the engine parameters during the transient allowed statistical analysis and the comparison between steady-state operating points. Cause-and-effect chains concerning the formation of soot are concluded by correlation analysis of parameters extracted from the flow field, the flame propagation and the soot luminosity.

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Optical Engines as Representative Tools in the Development of New Combustion Engine Concepts

Cited by 16 publications

References 19 publications

Experimental comparison between an optical and an all-metal large bore engine

Experimental comparison between an optical and an all-metal large bore engine

Optical study of gasoline substitution ratio and diesel injection strategy effects on dual-fuel combustion

Investigation of in-cylinder soot formation in a DISI engine during transient operation by simultaneous endoscopic PIV and flame imaging

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