Niedrig viskose Öle – eine Herausforderung für die Auslegung der Zylinderlaufbahn

Hübner, Matthias; Götze, Andreas

doi:10.1007/978-3-658-19291-4_27

Cited by 3 publications

(3 citation statements)

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“…Tribosystems of the same type are used for both, the single cylinder engine and the tribometer, see Section 2.1. The single test bench and its "instantaneous IMEP-method" to measure the piston group friction and detailed operating conditions as well as simulation boundary conditions are described in [40,48]. As already described in the present tribometer-based work, a mean friction benefit for starved lubrication conditions of 24% and 12% is found for ta-C-and a-C-coated piston rings (see Figure 7), respectively.…”

Section: Comparison To Fired Single Cylinder Enginementioning

confidence: 63%

“…Similarly, the line load according to the LST L LST is calculated with the applied normal load F n,LST per piston ring circumference length in contact based on the used segments, respectively. Figure 3a shows the mGHN calculated for a single cylinder engine as described in [48] at 1500 rpm and 6 bar indicated mean pressure (IMEP). In this calculation, the cylinder liner temperature distribution is assumed to be homogenous at 120 • C and therefore the dynamic viscosity is constant over stroke.…”

Section: Derivation Of Test Parametersmentioning

confidence: 99%

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Friction Response of Piston Rings for Application-like Starvation and Benefit of Amorphous Carbon Coatings

Michelberger

Jaitner²,

Hagel

et al. 2022

Coatings

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The oil supply at the interface between the top ring and the cylinder liner (TRCL) plays a major role in an internal combustion engines efficiency. In particular, the interface forms a trade-off between the serving of enough lubricant for sufficient lubrication conditions and emissions through subsequent combustion. This can lead to deficient top ring lubrication conditions. In this study, a new developed reciprocating long-stroke tribometer, enabling the variation of oil supply, is used to investigate such application-like starved lubrication conditions of the TRCL interface. With the simulative investigations, a comparison with the fired engine is possible. The performance of diamond-like carbon coatings is compared to standard nitrided piston rings. It was found that the tetrahedral amorphous carbon (ta-C) coatings exhibit up to 31% reduced friction as well as a lower wear under starved lubrication conditions. Simulative investigations show a good correlation between engine friction and tribometer measurements for selected oil supply conditions.

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Section: Comparison To Fired Single Cylinder Enginementioning

confidence: 63%

Section: Derivation Of Test Parametersmentioning

confidence: 99%

Friction Response of Piston Rings for Application-like Starvation and Benefit of Amorphous Carbon Coatings

Michelberger

Jaitner²,

Hagel

et al. 2022

Coatings

View full text Add to dashboard Cite

show abstract

“…The friction measurements were carried out on a fired single-cylinder engine using the indicated instantaneous mean effective pressure method (IIMEP, Technische Universität Dresden, Germany). [30,35] Hence, the measurement includes the total friction loss of the piston assembly. The engine exhibited a stroke of 94.6 mm and a bore diameter of 82 mm.…”

Section: Friction Evaluation Using Single Cylinder Engine Setupmentioning

confidence: 99%

Positive Effect of Periodic Micropatterns on Compression Ring Friction

Michelberger

Schell

Jaitner³

et al. 2023

Adv Eng Mater

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Internal combustion engines are increasingly regulated in regard to efficiency and environmental impact, which requires advanced optimization strategies of engine components. The contact between the top ring and the cylinder liner is critical to the efficiency of an internal combustion engine. As shown in a previous study, an amorphous carbon coating can greatly improve the friction properties of piston rings. This work expands on these results by fabricating laser‐interference‐induced microchannels on the coating perpendicular to the direction of movement with a mean depth of 0.97 and 3.13 μm spatial period to further optimize the tribology. Fired single‐cylinder engine measurements of the microtextured rings show a significant reduction in mean piston assembly friction of 5% for operation points that are relevant for urban transportation and up to 10% for specific operation points. Subsequent multibody elastohydrodynamic simulations prove that measured friction changes result from the compression ring microtexture. In particular, the microtexture increases the hydrodynamic pressure, reduces hydrodynamic losses, and leads to 20% lowered compression ring losses for an entire combustion cycle of the investigated operation point. In the future, such tribological concepts can be deployed in internal combustion engines that are powered by sustainable hydrogen or methanol.

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