Dual Fuel Injection (DI + PFI) for Knock and EGR Dilution Limit Extension in a Boosted SI Engine

Han, Taehoon; Lavoie, George A.; Wooldridge, Margaret S.; Boehman, André L.

doi:10.4271/2018-01-1735

Cited by 7 publications

(2 citation statements)

References 34 publications

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“…The initial flame development correlated with the initial burning (CA0010) as turbulent flame development is one of the most significant factors affecting EGR dilution tolerance in conventional SI engines. 27,28 The main chamber combustion process in pre-chamber engines has been characterized extensively for air-dilute systems, although less so for EGR-dilute operation. The turbulent jets emanating from a pre-chamber result in multiple, widely distributed ignition sites which rapidly consume the main chamber charge.…”

Section: Active Pre-chamber: Parametric Studies (λPc Eoipc and M...mentioning

confidence: 99%

Investigations into EGR dilution tolerance in a pre-chamber ignited GDI engine

Rohwer

Han

Shah

et al. 2022

International Journal of Engine Research

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EGR is a useful means to improve fuel economy in spark-ignited gasoline engines, especially under part-load conditions by means of reducing throttling losses. There is also a significant reduction in NOx emissions due to the reduced peak cylinder temperatures. However, the ability of conventional spark ignition systems to reliably ignite dilute mixtures limits the dilution tolerance due to the onset of combustion instability. In this study, an active pre-chamber system was evaluated at part load condition with various EGR rates using a regular grade full boiling range gasoline. A premixed air-fuel mixture was supplied to the pre-chamber, which assists in scavenging the residual mass fractions to enable reliable ignition of EGR dilute mixtures in the main combustion chamber. A range of pre-chamber injection, air-fuel mixture formulation, and ignition timing strategies were evaluated during the EGR sweeps. In addition, 0-D and 1-D simulations were conducted in GT-Power to assess the thermodynamic state and composition in the pre-chamber, as well as estimate the jet momentum at the various dilution rates. The active pre-chamber extended the EGR dilution limit from 20% for conventional SI to above 30%, with a higher pre-chamber flow rate (more scavenging) resulting in increased combustion stability. A tradeoff between the jet momentum and spark timing was observed when analyzing the GT-Power simulations and the pre-chamber jet momentum was found to decrease with increasing EGR rate. At unstable high EGR operation, no relation could be found between the pre-chamber indicated data and main chamber combustion stability.

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Section: Active Pre-chamber: Parametric Studies (λPc Eoipc and M...mentioning

confidence: 99%

Investigations into EGR dilution tolerance in a pre-chamber ignited GDI engine

Rohwer

Han

Shah

et al. 2022

International Journal of Engine Research

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“…3 shows that both dual injection configurations could improve the engine thermal/fuel efficiency compared with single injection, mainly due to ethanol's faster combustion speed and more spark advance allowed by ethanol's anti-knock ability. Regarding the emissions performance, Table 4 shows that both configurations could effectively reduce the PM and PN emissions when compared with GDI [104,121,[148][149][150][151]. For gaseous emissions, the variation trends are highly dependent on engine operating conditions and there are usually trade-offs between emission species such as NOx vs CO/HC due to their different or conflicting emission formation pathways [152].…”

Section: Ethanol-gasoline Dual Injection Enginesmentioning

confidence: 99%

Dual injection: An effective and efficient technology to use renewable fuels in spark ignition engines

Huang

Surawski

Zhuang

et al. 2021

Renewable and Sustainable Energy Reviews

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Modern spark ignition engines mostly use one injection system to deliver gasoline into the combustion chamber, using either direct injection or port fuel injection. Both technologies have their respective advantages. To integrate their advantages and to promote the use of renewable fuels, dual injection engines are in development in recent years. Dual injection represents an advanced combustion system and is a novel technology to address the urgent issues of sustainability and environmental protection. This study reviews the state-of-the-art research on dual injection spark ignition engines with a focus on renewable fuels, their advantages and engine performance. The main advantages of dual injection include greater control flexibility, enhanced cooling effect, knock mitigation, engine downsizing, extended lean-burn limits, higher thermal efficiency and reductions of several emission species. The most promising renewable fuels for dual injection are ethanol, methanol and hydrogen. Each renewable fuel is aimed at different advantages of dual injection.Alcohol-gasoline dual injection provides great anti-knock ability by taking advantage of alcohols' large enthalpies of vaporisation and high octane numbers, while hydrogen-gasoline dual injection provides extended lean-burn limits by taking advantage of hydrogen's low ignition energy, wide flammability limit and high flame speed. Direct injection of renewable fuels is the optimal injection strategy because it effectively utilises the strong cooling effect of alcohols or avoids the volumetric efficiency reduction and preignition of hydrogen. Dual injection generally demonstrates higher thermal efficiency than single injection.In addition, dual injection effectively reduces particulate emissions while there are usually trade-offs among gaseous emissions.

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