Design of an Endoscopic Fully Optically Accessible High-Speed Large-Bore Engine

Karmann, Stephan; Röhrle, Hannes; Klier, B; Prager, M.; Wachtmeister, Georg

doi:10.4271/03-15-06-0042

Cited by 2 publications

(11 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The engine peak pressure has to be reduced to prevent the cylinder head from failure, as it is weakened by the modifications needed for mounting the optic. Simulations estimate that a minimum peak pressure of 180 bar can be endured, as shown in Karmann et al 29 . The fisheye endoscope has a field angle of up to 180° and redirects the combustion’s natural chemiluminescence via a 45° deflection mirror to the camera mounted outside the engine.…”

Section: Engine Setupmentioning

confidence: 86%

“…In contrast to the modification described in Karmann et al, 29 the maximum lift of both valves is equalized. This is due to the use of a different cam profile in the experiment for Setups 1 and 2 than in the simulative investigations presented in Karmann et al 29 The intake valve lift is the same in all setups. The valve lift of the exhaust valve is changed slightly in setup 3 to take advantage of the higher in-cylinder pressure when the exhaust valve is open and to enhance the exhaust gas mass flow.…”

Section: Setup and Proceduresmentioning

confidence: 90%

“…Water cooling for the fisheye optic was intended for the experiments, like it is described in Karmann et al 29 Due to manufacturing issues that caused slight water leakage from the cooling duct into the lens setup, it had to be substituted by air cooling. Air cooling prevents contamination of the lens setting and still provides sufficient cooling to the lenses.…”

Section: Setup and Proceduresmentioning

confidence: 99%

“…According to the detailed description given in Karmann et al, 29 the exhaust valve lift was modified to account for the differences in gas exchange behavior. In contrast to the modification described in Karmann et al, 29 the maximum lift of both valves is equalized. This is due to the use of a different cam profile in the experiment for Setups 1 and 2 than in the simulative investigations presented in Karmann et al 29 The intake valve lift is the same in all setups.…”

Section: Setup and Proceduresmentioning

confidence: 99%

“…Only a brief summary will be given here, as a detailed description of the three different engine setups can be found, for instance, in Eicheldinger et al 28 for the all-metal engine and in Karmann et al 29 for the optical setups. For simplification, the engine setups are denoted as 1 (all-metal engine), 2 (full-load optical setup) and 3 (full optical setup).…”

Section: Engine Setupmentioning

confidence: 99%

See 4 more Smart Citations

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

Karmann

Eicheldinger

Prager

et al. 2022

International Journal of Engine Research

View full text Add to dashboard Cite

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.

show abstract

Section: Engine Setupmentioning

confidence: 86%

Section: Setup and Proceduresmentioning

confidence: 90%

Section: Setup and Proceduresmentioning

confidence: 99%

Section: Setup and Proceduresmentioning

confidence: 99%

Section: Engine Setupmentioning

confidence: 99%

See 3 more Smart Citations

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

Karmann

Eicheldinger

Prager

et al. 2022

International Journal of Engine Research

View full text Add to dashboard Cite

show abstract

Optical and Thermodynamic Investigations of a Methane- and Hydrogen-Blend-Fueled Large-Bore Engine Using a Fisheye Optical System

et al. 2023

Self Cite

View full text Add to dashboard Cite

The following paper presents thermodynamic and optical investigations of hydrogen-enriched methane combustion, showing the potential of a hydrogen admixture as a means to decarbonize stationary power generation. The optical investigations are carried out through a fisheye optical system directly mounted into the combustion chamber, replacing one exhaust valve. All of the tests were carried out with constant fuel energy producing 16 bar indicated mean effective pressure. The engine under investigation is a port-fueled 4.8 l single-cylinder large-bore research engine. The test series compared the differences between a conventional spark plug and an unscavenged pre-chamber spark plug as an ignition system. The fuel blends under investigation are 5 and 10%V hydrogen mixed with methane and pure natural gas acting as a reference fuel. The thermodynamic results show a beneficial influence of the hydrogen admixture on both ignition systems and for all variations concerning the lean running limit, combustion stability and indicated efficiency, with the most significant influence being visible for the tests using conventional spark plugs. With the unscavenged pre-chamber spark plug and the combustion of the 10%V hydrogen admixture, an increase in the indicated efficiency of 0.8% compared to NG is achievable. The natural chemiluminescence intensity traces were observed to be predominantly influenced by the air–fuel equivalence ratio. This results in a 20% higher intensity for the unscavenged pre-chamber spark plug for the combustion of 10%V hydrogen compared to the conventional spark plug. This is also visible in the evaluations of the flame color derived from the dewarped combustion image series. The investigation of the torch flames also shows a difference in the air–fuel equivalence ratio but not between the different fuels. The results encourage the development of hydrogen-based fuels and the potential to store surplus sustainable energy in the form of hydrogen in existing gas grids.

show abstract

Design of an Endoscopic Fully Optically Accessible High-Speed Large-Bore Engine

Cited by 2 publications

References 0 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 and Thermodynamic Investigations of a Methane- and Hydrogen-Blend-Fueled Large-Bore Engine Using a Fisheye Optical System

Contact Info

Product

Resources

About