This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
Experimental Evaluation of Lean-burn and EGR as Load Control Strategies for Methanol Engines
Technical Paper
2012-01-1283
ISSN: 0148-7191, e-ISSN: 2688-3627
Annotation ability available
Sector:
Language:
English
Abstract
The use of light alcohols as SI engine fuels can help to increase energy security and offer the prospect of carbon neutral transport. These fuels enable improvements in engine performance and efficiency as several investigations have demonstrated. Further improvements in efficiency can be expected when switching from throttled stoichiometric operation to strategies using mixture richness or exhaust gas recirculation (EGR) to control load while maintaining wide open throttle (WOT).
In this work the viability of throttleless load control using EGR (WOT EGR) or mixture richness (WOT lean burn) as operating strategies for methanol engines was experimentally verified. Experiments performed on a single-cylinder engine confirmed that the EGR dilution and lean burn limit of methanol are significantly higher than for gasoline. On methanol, both alternative load control strategies enable relative indicated efficiency improvements of about 5% compared to throttled stoichiometric operation. This is mainly due to the absence of throttling losses, reduced cooling and dissociation losses caused by the lower in-cylinder temperatures obtained through dilution. On gasoline, the efficiency benefits are limited because of the slow burn rates and high cyclic variability associated with dilution. The reduced in-cylinder temperatures also allow a significant decrease in engine-out NOx emissions, but this is not sufficient to justify the loss in three-way catalyst (TWC) efficiency associated with lean combustion.
Based on these results, it was concluded that the WOT EGR load control strategy seems more promising as it allows to significantly increase the part load efficiency without sacrificing in terms of tailpipe emissions. A second series of experiments was carried out on an engine more suitable for EGR dilution. This engine was derived from a four-cylinder turbocharged diesel engine and had a compression ratio of 19.5:1. This elevated compression ratio, in combination with turbocharging and high levels of in-cylinder turbulence allowed to raise the burning rates enough to use EGR in levels up to 50% with limited cycle-to-cycle variation. Throttleless load control was possible down to 3 bar BMEP in this way.
Thanks to the elevated compression ratio peak brake thermal efficiencies of up to 42% were obtained. At part loads, relative efficiency improvements up to 20% were achieved and the engine-out NOx emissions were cut down to values that are negligible compared to throttled stoichiometric load control. These results confirm that WOT EGR operation is an interesting load control strategy for dedicated methanol engines, provided that the engine design lends itself to high dilution levels.
Recommended Content
| Technical Paper | Spark Ignition Engine Control Variables Study |
| Technical Paper | The Relation Between Knock and Exhaust Emissions of a Spark Ignition Engine |
Authors
Topic
Citation
Vancoillie, J., Sileghem, L., Van de Ginste, M., Demuynck, J. et al., "Experimental Evaluation of Lean-burn and EGR as Load Control Strategies for Methanol Engines," SAE Technical Paper 2012-01-1283, 2012, https://doi.org/10.4271/2012-01-1283.Also In
References
- Pearson, R.J. Turner, J.W.G. Peck, A.J. “Gasoline-ethanol-methanol tri-fuel vehicle development and its role in expediting sustainable organic fuels for transport” IMechE Low Carbon Vehicles Conference London, UK 2009
- Specht, M. Bandi, A. “Renewable carbon-based transportation fuels” Renewable Energy 3C 414 482 Springer Berlin Heidelberg, Berlin 2006
- Olah, G.A. Goeppert, A. Prakash, G.K. “Beyond Oil and Gas: the Methanol Economy.” Wiley-VCH Verlag CmbH & Co., KGaA Weinheim, Germany 2006
- Allen, R. Baker, N. Keating, E. Negri, J. et al. “IRL Aurora V8 Design and Development,” SAE Technical Paper 983037 1998 10.4271/983037
- Verhelst, S. Wallner, T. “Hydrogen-fueled internal combustion engines” Progress in Energy and Combustion Science 35 6 490 527 2009
- Vancoillie, J. Verhelst, S. “Modeling the combustion of light alcohols in SI engines: a preliminary study” FISITA 2010 World Automotive Congress Budapest, Hungary 2010
- Brusstar, M. Stuhldreher, M. Swain, D. Pidgeon, W. “High Efficiency and Low Emissions from a Port-Injected Engine with Neat Alcohol Fuels,” SAE Technical Paper 2002-01-2743 2002 10.4271/2002-01-2743
- Neame, G. Gardiner, D. Mallory, R. Rao, V. et al. “Improving the Fuel Economy of Stoichiometrically Fuelled S.I. Engines by Means of EGR and Enhanced Ignition - A Comparison of Gasoline, Methanol and Natural Gas,” SAE Technical Paper 952376 1995 10.4271/952376
- Abd-Alla, G.H. “Using exhaust gas recirculation in internal combustion engines: a review” Energy Conversion and Management 43 8 1027 1042 2002
- Pannone, G. Johnson, R. “Methanol as a Fuel for a Lean Turbocharged Spark ignition Engine,” SAE Technical Paper 890435 1989 10.4271/890435
- Heywood, J.B. “Internal Combustion Engine Fundamentals” McGraw-Hill series in mechanical engineering MacGraw-Hill New York 1988
- Vancoillie, J. Verhelst, S. Demuynck, J. “Laminar Burning Velocity Correlations for Methanol-Air and Ethanol-Air Mixtures Valid at SI Engine Conditions,” SAE Technical Paper 2011-01-0846 2011 10.4271/2011-01-0846
- Germane, G. Wood, C. Hess, C. “Lean Combustion in Spark-Ignited Internal Combustion Engines - A Review,” SAE Technical Paper 831694 1983 10.4271/831694
- Dunn-Rankin, D. “Lean combustion: technology and control” Elsevier Academic Press Burlington, MA 2008
- Turner, J. Pearson, R. Holland, B. Peck, R. “Alcohol-Based Fuels in High Performance Engines,” SAE Technical Paper 2007-01-0056 2007 10.4271/2007-01-0056
- Wallner, T. Frazee, R. “Study of Regulated and Non-Regulated Emissions from Combustion of Gasoline, Alcohol Fuels and their Blends in a DI-SI Engine,” SAE Technical Paper 2010-01-1571 2010 10.4271/2010-01-1571
- Vancoillie, J. et al. “Efficiency Comparison Between Hydrogen, Methanol And Gasoline On A Production-Type Four-Cylinder Engine” 13th EAEC European Automotive Conference Valencia 2011