A comparison between two-position variable compression ratio and continuously variable compression ratio engines using numerical simulation
Paper
Paper/Presentation Title | A comparison between two-position variable compression ratio and continuously variable compression ratio engines using numerical simulation |
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Presentation Type | Paper |
Authors | Malpress, Ray (Author) and Buttsworth, David R. (Author) |
Editors | Callahan, Tim |
Journal or Proceedings Title | Proceedings of the ASME Internal Combustion Engine Division Fall Technical Conference (ICEF 2009) |
Number of Pages | 11 |
Year | 2009 |
Place of Publication | United States |
ISBN | 9780791843635 |
9780791838587 | |
Digital Object Identifier (DOI) | https://doi.org/10.1115/ICEF2009-14042 |
Web Address (URL) of Paper | http://www.asmeconferences.org/ICEF09/ |
Conference/Event | ASME Internal Combustion Engine Division Fall Technical Conference (ICEF 2009) |
Event Details | ASME Internal Combustion Engine Division Fall Technical Conference (ICEF 2009) Event Date 27 to end of 30 Sep 2009 Event Location Lucerne, Switzerland |
Abstract | Fuel consumption for the New European Driving Cycle (NEDC) is assessed via numerical simulation for a vehicle operating with two types of variable compression ratio device: i) a continually variable compression ratio (VCR) device that optimises efficiency at all loads, and ii) a VCR device that allows the engine to operate at one of two discrete compression ratios. The simulated engine configuration uses late intake valve closing (LIVC). A maximum geometric compression ratio (GCR) of 17:1 is adopted in the simulations resulting in a constant effective compression ratio of 10.2:1 in all configurations. Reduction from full load is achieved in the simulation with LIVC until the maximum GCR is reached after which lower loads are achieved through throttling. In the two-position VCR engine simulation, the full load range is achieved through throttling in combination with LIVC. At part load, in combination with LIVC, the VCR devices increase the geometric compression ratio to return the effective compression ratio to that for full load in each case. The simulations indicate that the increase in net fuel consumption over a driving cycle is effectively no different for the two-position VCR engine relative to a continually variable CR and this justifies further research into two-position VCR technology. Net fuel consumption can also be improved by the use of a limited acceleration that maintains the engine in the reduced compression stroke configuration. An acceleration rate with a driver feedback mechanism is proposed which, in combination with a two-position VCR engine, shows potential for significant reduction in fuel consumption of greater than 15% relative to the full compression, fixed CR configuration for the NEDC. |
Keywords | variable compression ratio; two-position; atkinson cycle; new european driving cycle |
ANZSRC Field of Research 2020 | 400201. Automotive combustion and fuel engineering |
401706. Numerical modelling and mechanical characterisation | |
Public Notes | Files associated with this item cannot be displayed due to copyright restrictions. |
Byline Affiliations | Computational Engineering and Science Research Centre |
https://research.usq.edu.au/item/9z3vv/a-comparison-between-two-position-variable-compression-ratio-and-continuously-variable-compression-ratio-engines-using-numerical-simulation
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