CO2-emission reduction by means of enhancement of the thermal conversion efficiency of ice cycles
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Date
Authors
Gheorghiu, Victor
Journal Title
Journal ISSN
Volume Title
Publisher
International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics
Abstract
Paper presented at the 7th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Turkey, 19-21 July, 2010.
Most recent implementations of the Atkinson cycle are not ideal from the point of view of thermal conversion efficiency (TCE). For example, Toyota has put a gasoline engine in its Prius II which should achieve high efficiency by using a modified Atkinson cycle based on variable intake valve timing management. Firstly, this implementation of the Atkinson cycle is not the ideal solution because some of the air is first sucked from the intake manifold into the cylinder and subsequently returned back there. Consequently, the oscillating air stream reduces the thermal conversion efficiency of this cycle to a considerable extent Secondly, this implementation of the Atkinson cycle only reaches low levels of indicated mean pressure (IMEP) and, thirdly, it is not suitable for part load engine operating points (BOP) because of the lower TCE. For these reasons, this implementation of the Atkinson cycle is only suitable for hybrid vehicles, where the engine - because it is not directly linked mechanically to the wheels - works only in its best EOP. This paper analyzes the losses in TCE of internal combustion engine (ICE) - especially for the Atkinson cycles - in detail, and a proposal is made for their reduction for aspirated and especially for high pressure supercharged engines.
Most recent implementations of the Atkinson cycle are not ideal from the point of view of thermal conversion efficiency (TCE). For example, Toyota has put a gasoline engine in its Prius II which should achieve high efficiency by using a modified Atkinson cycle based on variable intake valve timing management. Firstly, this implementation of the Atkinson cycle is not the ideal solution because some of the air is first sucked from the intake manifold into the cylinder and subsequently returned back there. Consequently, the oscillating air stream reduces the thermal conversion efficiency of this cycle to a considerable extent Secondly, this implementation of the Atkinson cycle only reaches low levels of indicated mean pressure (IMEP) and, thirdly, it is not suitable for part load engine operating points (BOP) because of the lower TCE. For these reasons, this implementation of the Atkinson cycle is only suitable for hybrid vehicles, where the engine - because it is not directly linked mechanically to the wheels - works only in its best EOP. This paper analyzes the losses in TCE of internal combustion engine (ICE) - especially for the Atkinson cycles - in detail, and a proposal is made for their reduction for aspirated and especially for high pressure supercharged engines.
Description
Keywords
Co2 emission reduction, Enhancement of thermal conversion efficiency of ice cycles, Atkinson cycle, Hybrid vehicles, Thermal conversion efficiency, Tce, Indicated mean pressure, Eop, Imep, Engine operating points, Ice, Internal combustion engine
Sustainable Development Goals
Citation
Gheorghiu, V 2010, 'Co2-emission reduction by means of enhancement of the thermal conversion efficiency of ice cycles', Paper presented to the 7th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Turkey, 19-21 July 2010.