Impact of EGR Quality on the Total Inert Dilution Ratio

Alger, Terrence; Gukelberger, Raphael; Gingrich, Jess

doi:10.4271/2016-01-0713

Cited by 10 publications

(4 citation statements)

References 22 publications

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“…Further, on-engine demonstrations of dEGR implemented on comercially available gasoline engines were performed by researchers at Southwest Research Institute. 15–24 These demonstrations continued to focus on improving engine efficiency by increased CR, boosting, and the development of the patented dEGR mixer.…”

Section: Introductionmentioning

confidence: 99%

Evaluating dedicated exhaust gas recirculation on a stoichiometric industrial natural gas engine

Roekel

Montgomery

Singh

et al. 2019

International Journal of Engine Research

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Due to the market presence that natural gas has and is expected to have in the future energy sector, research and development of novel natural gas combustion strategies to increase power density, lower total emissions, and increase overall efficiency is warranted. Dilution whether by excess air or by exhaust gas recirculation has historically been implemented on diesel, natural gas, and gasoline engines to mitigate various regulated emissions. In the large industrial natural gas engine industry, excess air dilution or ultra-lean-burn operation has afforded lean-burn engines increased power density and reduced NO x emissions. This advance in technology has allowed lean-burn engines to compete in markets such as electrical power generation which previously they had not been able. However, natural gas engines utilizing a non-selective catalytic reduction system or three-way catalyst must operate under stoichiometric conditions and thus are limited in power density by exhaust gas temperatures. In previous gasoline small engine research, a novel exhaust gas recirculation technique called dedicated exhaust gas recirculation was shown to have a positive impact on engine-out emissions of NO x and unburned hydrocarbons while also lowering exhaust component temperatures. This work seeks to understand the consequences of implementing a dedicated exhaust gas recirculation system on a multi-cylinder stoichiometric industrial natural gas engine. The results of this initial evaluation demonstrate reductions in engine-out NO x and CO emissions and improvements in engine-out exhaust gas temperatures with the dedicated exhaust gas recirculation technique. However, in a low-turbulence combustion chamber, dedicated exhaust gas recirculation significantly lowers the overall rate of combustion and results in significant differences in cylinder-to-cylinder combustion.

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Section: Introductionmentioning

confidence: 99%

Evaluating dedicated exhaust gas recirculation on a stoichiometric industrial natural gas engine

Roekel

Montgomery

Singh

et al. 2019

International Journal of Engine Research

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Section: Introductionmentioning

confidence: 99%

“…The dedicated cylinder(s) can be operated at fuel rich conditions which results in an exhaust composition that includes partial oxidation combustion products such as hydrogen (H 2 ) and carbon monoxide (CO). [9][10][11][12] In contrast to the method of control that conventional HPL and LPL systems utilize, namely an EGR valve, a dedicated EGR system does not include an EGR valve. Because EGR valves are exposed to relatively high exhaust gas temperatures removing the EGR valve from an engine design is a significant benefit in terms of the long term reliability of the EGR system.…”

Section: Introductionmentioning

confidence: 99%

“…Further fundamental work by SWRi focused on fuel anti-knock index in an engine equipped with dedicated EGR 19 and characterizing engine performance as the composition of recirculated exhaust gases is changed. 10 Two publications, one by Van Roekel et al 13 and another by Mitchell and Kocsis 20 have demonstrated dedicated EGR implemented on multi-cylinder natural gas engines. The work by Mitchell and Kocsis 20 was done on a 6-cylinder, 12 L Cummins ISX G engine.…”

Section: Introductionmentioning

confidence: 99%

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Response surface method optimization of a natural gas engine with dedicated exhaust gas recirculation

Roekel

Montgomery

Singh

et al. 2021

International Journal of Engine Research

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Stoichiometric industrial natural gas engines rely on robust design to achieve consumer driven up-time requirements. Key to this design are exhaust components that are able to withstand high combustion temperatures found in this type of natural gas engine. The issue of exhaust component durability can be addressed by making improvements to materials and coatings or decreasing combustion temperatures. Among natural gas engine technologies shown to reduce combustion temperature, dedicated exhaust gas recirculation (EGR) has limited published research. However, due to the high nominal EGR rate it may be a technology useful for decreasing combustion temperature. In previous work by the author, dedicated EGR was implemented on a Caterpillar G3304 stoichiometric natural gas engine. Examination of combustion statistics showed that, in comparison to a conventional stoichiometric natural gas engine, operating with dedicated EGR requires adjustments to the combustion recipe to achieve acceptable engine operation. This work focuses on modifications to the combustion recipe necessary to improve combustion statistics such as coefficient of variance of indicated mean effective pressure (COV of IMEP), cylinder-cylinder indicated mean effective pressure (IMEP), location of 50% mass fraction burned, and 10%–90% mass fraction burn duration. Several engine operating variables were identified to affect these combustion statistics. A response surface method (RSM) optimization was chosen to find engine operating conditions that would result in improved combustion statistics. A third order factorial RSM optimization was sufficient for finding optimized operating conditions at 3.4 bar brake mean effective pressure (BMEP). The results showed that in an engine with a low turbulence combustion chamber, such as a G3304, optimized combustion statistics resulted from a dedicated cylinder lambda of 0.936, spark timing of 45° before top dead center (°bTDC), spark duration of 365 µs, and intake manifold temperature of 62°C. These operating conditions reduced dedicated cylinder COV of IMEP by 10% (absolute) and the difference between average stoichiometric cylinder and dedicated cylinder IMEP to 0.19 bar.

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