Wall Heat Transfer in a Multi-Link Extended Expansion SI-Engine

Langwiesner, Morris; Krueger, C.; Donath, Sebastian; Bargende, Michael

doi:10.4271/2017-24-0016

Cited by 2 publications

(1 citation statement)

References 7 publications

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“…With models using the mean piston speed (Woschni, Hohenberg) best results were achieved, when the mean piston speed during expansion stroke was assumed as linearly rising over crank angle from top dead centre to the bottom dead centre. In [13] it is shown that the Bargende heat transfer equation, using the instantaneous piston speed, can cope with the Atkinson cycle piston movement without adjustment.…”

Section: Wall Heat Transfermentioning

confidence: 99%

Extended expansion linkage engine: a concept to increase the efficiency

Dumböck

Schutting

Eichlseder

2018

Automot. Engine Technol.

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In a broad-based survey, the reciprocating piston engine with extended expansion stroke was found to have the highest efficiency potential for passenger car propulsion. To confirm the predicted efficiency, three different prototype engines were built and measured on testbed. Measurements were complemented with thermodynamic simulations. Investigations focused on naturally aspirated and supercharged SI engines. It could be shown that a naturally aspirated SI engine with an expansion ratio of 2 gains an efficiency improvement of 7 percentage points compared to a conventional crank train engine. It was also found that the extended expansion has no inherent effect to combustion, emission formation and wall heat transfer. Major effort was made to assess the Miller cycle as a thermodynamic alternative to the crank train with extended expansion. Measurements and simulations revealed that Miller suffers in a way from higher wall heat and gas exchange losses cutting a substantial share of the efficiency potential of an equivalent crank train solution. Keywords Extended expansion • Atkinson cycle • Miller cycle Abbreviations atm Atmospheric AFR Air to fuel ratio BDC Bottom dead centre BP Boost pressure CA Crank angle c Compression COMP Compressor Volume ratio Ex Expansion EE Extended expansion EGBP Exhaust gas back pressure c Compression ratio

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Section: Wall Heat Transfermentioning

confidence: 99%