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EGR System Optimization for Light-Duty Gasoline Compression Ignition (GCI) Engine
ISSN: 0148-7191, e-ISSN: 2688-3627
Published April 06, 2021 by SAE International in United States
This content contains downloadable datasetsAnnotation ability available
Event: SAE WCX Digital Summit
Increasingly stringent exhaust and CO2 emissions regulations are driving advancements in combustion and after-treatment technologies in the passenger vehicle sector. One major challenge is to achieve low emissions over the full operating map as required by Real Driving Emissions (RDE) legislation. Gasoline Compression Ignition (GCI), an advanced combustion concept, has shown potential to increase fuel efficiency and reduce emissions. GCI harnesses gasoline’s low reactivity for longer ignition delay, thus promoting partially premixed air-fuel mixture for efficient combustion. To maintain low engine-out NOx over the load range, high Exhaust Gas Recirculation (EGR) is required that consequently elevates boost pressure requirements. To meet the high boost and EGR demands, while minimizing pumping losses require air-system optimization.
This work presents a detailed investigation of EGR system optimization for a prototype 2.6L, four-cylinder, Light-Duty (LD) Gasoline Compression Ignition (GCI) engine using RON92 gasoline at a geometric compression ratio (CR) of 17. Several alternative EGR configurations were evaluated, including conventional layouts such as high-pressure EGR (HP-EGR) loop, low-pressure EGR (LP-EGR) loop, dual-loop EGR (DL-EGR) and a novel EGR configuration. A GT-Power based 1-D engine model was used, to quantify and compared the EGR configurations candidates over both steady-state and transient engine operations. Time-to-torque (TTT) and EGR delivery time were compared.
The HP-EGR alone configuration appeared unfit, by causing inefficient turbocharging, Whereas, the LP-EGR only improved complemented turbocharger performance at the expense of high pumping losses at high engine speeds. A dual-loop EGR system offered a more optimized engine system performance.
A customized (novel) EGR configuration, demonstrated performance benefits equivalent to a dual-loop EGR system without the complexity and packaging issues of DL-EGR system. For steady-state engine operation, the system exhibited pumping benefit in the range of 20 to 90 kPa at engine speed over 2500 RPM. For idle to 2500 RPM full load transient engine condition, the novel EGR configuration enabled approximately two times faster EGR delivery, but, also caused a noticeable delay in TTT, compared to a conventional LP-EGR configuration. Using an integrated starter generator (ISG) assist, the load response lag fully disappeared and the engine system demonstrated almost instantaneous torque. The novel EGR system not only provided the best system performance benefits but also offered superior trade-offs for cost, complexity and integration.
CitationKumar, P. and Sellnau, M., "EGR System Optimization for Light-Duty Gasoline Compression Ignition (GCI) Engine," SAE Technical Paper 2021-01-0515, 2021, https://doi.org/10.4271/2021-01-0515.
Data Sets - Support Documents
|Unnamed Dataset 1|
- California Low-Emission Vehicle Regulations for Passenger Cars ww2.arb.ca.gov 2019
- https://ec.europa.eu/clima/policies/transport/vehicles/regulation 2019
- Kalghatgi , G.T. , Risberg , P. , and Angstrom , H.-E. Partially Pre-Mixed Auto-Ignition of Gasoline to Attain Low Smoke and Low NOx at High Load in a Compression Ignition Engine and Comparison with a Diesel Fuel SAE Technical Paper 2007-01-0006 2007 https://doi.org/10.4271/2007-01-0006
- Sellnau , M. , Sinnamon , J. , Hoyer , K. , and Husted , H. Gasoline Direct Injection Compression Ignition (GDCI) - Diesel-Like Efficiency with Low CO2 Emissions SAE Int. J. Engines 4 1 2010 2022 2011 https://doi.org/10.4271/2011-01-1386
- Zhang , Y. , Kumar , P. , Pei , Y. , Traver , M. et al. An Experimental and Computational Investigation of Gasoline Compression Ignition Using Conventional and Higher Reactivity Gasolines in a Multi-Cylinder Heavy-Duty Diesel Engine SAE Technical Paper 2018-01-0226 2018 https://doi.org/10.4271/2018-01-0226
- Morey , B. Cooled EGR Shows Benefits for Gasoline Engines Automotive Engineering Magazine 2014 https://www.sae.org/news/2014/09/cooled-egr-shows-benefits-for-gasoline-engines
- Kumar , P. , Pei , Y. , Traver , M. , and Watson , J. System Level 1-D Analysis of an Air-System for a Heavy-Duty Gasoline Compression Ignition Engine SAE Technical Paper 2019-01-0240 2019 https://doi.org/10.4271/2019-01-0240
- Hoyer , K. , Sellnau , M. , Sinnamon , J. , and Husted , H. Boost System Development for Gasoline Direct-Injection Compression-Ignition (GDCI) SAE Int. J. Engines 6 2 815 826 2013 https://doi.org/10.4271/2013-01-0928
- Chadwell , C. , Alger , T. , Roberts , C. , and Arnold , S. Boosting Simulation of High Efficiency Alternative Combustion Mode Engines SAE Int. J. Engines 4 1 375 393 2011 https://doi.org/10.4271/2011-01-0358
- Lee , H. , Jo , C. , Yoon , S. , YI , S. et al. Optimization of Dual Loop EGR of a V6 3.0 Liter Diesel Engine for CO2 Reduction SAE Technical Paper 2013-01-0316 2013 https://doi.org/10.4271/2013-01-0316
- Mao , B. , Yao , M. , Zheng , Z. , Li , Y. et al. Effects of Dual Loop EGR on Performance and Emissions of a Diesel Engine SAE Technical Paper 2015-01-0873 2015 https://doi.org/10.4271/2015-01-0873
- Gukelberger , R. , Gingrich , J. , Alger , T. , Almaraz , S. et al. LPL EGR and D-EGR® Engine Concept Comparison Part 1: Part Load Operation SAE Int. J. Engines 8 2 570 582 2015 https://doi.org/10.4271/2015-01-0783
- Khaled , N. , Cunningham , M. , Pekar , J. , Fuxman , A. et al. Multivariable Control of Dual Loop EGR Diesel Engine with a Variable Geometry Turbo SAE Technical Paper 2014-01-1357 2014 https://doi.org/10.4271/2014-01-1357
- Vítek , O. , Macek , J. , Polášek , M. , Schmerbeck , S. et al. Comparison of Different EGR Solutions SAE Technical Paper 2008-01-0206 2008 https://doi.org/10.4271/2008-01-0206
- Kobayashi , M. , Aoyagi , Y. , Adachi , T. , Murayama , T. et al. Effective BSFC and NOx Reduction on Super Clean Diesel of Heavy Duty Diesel Engine by High Boosting and High EGR Rate SAE Technical Paper 2011-01-0369 2011 https://doi.org/10.4271/2011-01-0369
- Sellnau , M. , Foster , M. , Moore , W. , Sinnamon , J. et al. Pathway to 50% Brake Thermal Efficiency Using Gasoline Direct Injection Compression Ignition SAE Technical Paper 2019-01-1154 2019 https://doi.org/10.4271/2019-01-1154
- GT-Power Software, GT-ISE Version 2020 2018
- Kumar , P. , and Sellnau , M. Evaluation of Fast Warm-Up Strategies for a Light-Duty Gasoline Compression Ignition (GCI) Engine SAE Technical Paper 2020-01-0317 2020 https://doi.org/10.4271/2020-01-0317