Cooled exhaust-gas recirculation for fuel economy and emissions improvement in gasoline engines

Alger, Terrence; Gingrich, Jess; Roberts, Charles E.; Mangold, Barrett

doi:10.1177/1468087411402442

Cited by 94 publications

(48 citation statements)

References 27 publications

(39 reference statements)

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“…Overall, the theoretical EGR tolerance results for the high-efficiency gasoline engine compare well to the experimental results from SwRI's HEDGE engine. 23 The variation in EGR with speeds other than 2000 r/ min is not evaluated in this work, as experimental results indicate that EGR varies little with speed, particularly in the region where the engine typically operates (1000-2000 r/min, 0-5 bar BMEP). This is likely due to similar trends in u# and S L as engine speed varies.…”

Section: Flammabilitymentioning

confidence: 97%

“…Stable combustion is maintained up to almost 30% EGR, at which point flammability limits are encountered. 23 However, due to limitations of the turbocharger system, EGR is decreased at high-load and low-speed conditions to increase torque and achieve the desired BMEP. 23 To understand the ways in which dilute operation can be enhanced or restricted, it is helpful to review the flame development process and the related abnormal combustion phenomena.…”

Section: Flammability Limitsmentioning

confidence: 99%

“…23 However, due to limitations of the turbocharger system, EGR is decreased at high-load and low-speed conditions to increase torque and achieve the desired BMEP. 23 To understand the ways in which dilute operation can be enhanced or restricted, it is helpful to review the flame development process and the related abnormal combustion phenomena. During the initial flame development period, misfire occurs if the mixture is too dilute and there is insufficient fuel for the flame to ignite.…”

Section: Flammability Limitsmentioning

confidence: 99%

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Scaling and dimensional methods to incorporate knock and flammability limits in models of high-efficiency gasoline and ethanol engines

Lewis

Ortiz-Soto

Lavoie

et al. 2014

International Journal of Engine Research

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Recent work has shown the utility of using simplified models with prescribed burn rates to assess the potential of advanced combustion strategies to increase engine efficiency. However, this approach can be improved by incorporating knock and flammability limits. This work incorporates such limits using a combination of simplified conceptual models that are based on theoretical understanding of knock and flame phenomenon and calibration with experimental results. Using this method, the ideal (unconstrained) and feasible (constrained by knock and flammability) potential of a high efficiency gasoline and E85 engine are compared against a baseline naturally aspirated gasoline engine. Turbocharging, dilution with EGR, and higher compression ratios are used to increase the efficiency potential of the high efficiency gasoline and E85 engines. Results demonstrate the benefit of using this simplified approach in modeling high efficiency engines: the high efficiency gasoline engine is most limited by knock while the E85 engine is limited much less; also increased EGR can be used for the E85 engine due to the higher flame speeds of ethanol. Fuel economy maps are created for each engine/fuel strategy and evaluated in a vehicle model to obtain fuel economy results. Results comparing feasible engines show that peak brake thermal efficiency (BTE) is increased by 11.4% for the high efficiency gasoline engine and 17.8% for the E85 engine, as compared to the baseline gasoline engine. Projected vehicle fuel economy (energy equivalent) improvements are 30.1% for the high efficiency gasoline, and 40.9% for the E85 engine relative to baseline.

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Section: Flammabilitymentioning

confidence: 97%

Section: Flammability Limitsmentioning

confidence: 99%

Section: Flammability Limitsmentioning

confidence: 99%

See 1 more Smart Citation

Scaling and dimensional methods to incorporate knock and flammability limits in models of high-efficiency gasoline and ethanol engines

Lewis

Ortiz-Soto

Lavoie

et al. 2014

International Journal of Engine Research

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“…Additionally, state-of-the-art technologies such as highly boosting, down-speeding, downsizing and high compression ratio are introduced to meet the upcoming severe fuel consumption demand in SI engines [10][11][12]. A recent review on technologies to recover exhaust heat from internal combustion engines can be found in [13].…”

Section: Introductionmentioning

confidence: 98%

A new and efficient mechanism for spark ignition engines

Shadloo¹,

Poultangari²,

Jamalabadi³

et al. 2015

Energy Conversion and Management

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“…Various knock suppression methods [9,10,11,12,13] are developed over the years, such as cooled exhaust gas recirculation, direct injection of fuel into cylinder, multiple fuel injections and variable valve timing [14,15,16]. Alternatively, one seeks fuels that are less prone to auto-ignition.…”

Section: Introductionmentioning

confidence: 99%

Effect of Timing and Location of Hotspot on Super Knock during Pre-ignition

Ali

Pérez

Vedharaj

et al. 2017

SAE Technical Paper Series

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Pre-ignition in SI engine is a critical issue that needs addressing as it may lead to super knock event. It is widely accepted that pre-ignition event emanates from hot spot(s) that can be anywhere inside the combustion chamber. The location and timing of hotspot is expected to influence the knock intensity from a pre-ignition event. In this study, we study the effect of location and timing of hot spot inside the combustion chamber using numerical simulations. The simulation is performed using a three-dimensional computational fluid dynamics (CFD) code, CONVERGE™. We simulate 3-D engine geometry coupled with chemistry, turbulence and moving structures (valves, piston). G-equation model for flame tracking coupled with multi-zone model is utilized to capture auto-ignition (knock) and solve gas phase kinetics. A parametric study on the effect of hot spot timing and location inside the combustion chamber is performed. The hot spot timing considered are -180 CAD, -90 CAD and -30 CAD and the locations of the hot spots are in the center and two edges of the piston surfaces. Simulation results for normal combustion cycle are validated against the experimental data. The simulation results show great sensitivity to the hot spot timing, and the influence of local temperature gradient is noted to be significant. In case of early hot spot timing of -180 CAD, the pre-ignition event did not lead to super knock. Nevertheless, at late hot spot timing, super knock was realized. On the other hand, the effect of hot spot location on pre-ignition event depends on the geometry of the combustion chamber.

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Cooled exhaust-gas recirculation for fuel economy and emissions improvement in gasoline engines

Cited by 94 publications

References 27 publications

Scaling and dimensional methods to incorporate knock and flammability limits in models of high-efficiency gasoline and ethanol engines

Scaling and dimensional methods to incorporate knock and flammability limits in models of high-efficiency gasoline and ethanol engines

A new and efficient mechanism for spark ignition engines

Effect of Timing and Location of Hotspot on Super Knock during Pre-ignition

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