Exhaust Gas Aftertreatment for Lean Gasoline Direct Injection Engines - Potential for Future Applications

Philipp, S.; Hoyer, R.; Adam, Frank; Eckhoff, S.; Wunsch, R.; Schoen, Christof; Vent, Guido

doi:10.4271/2013-01-1299

Cited by 14 publications

(7 citation statements)

References 4 publications

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“…Three way catalysts can't function well in these conditions, and the NOx levels are generally too high for practical urea SCR. Philipp, et al [110] described the emission control system for the Mercedes-Benz lean burn gasoline engine for Euro 6 and the concept system for the US version. They combine the TWC with the NOx storage catalyst (NSC; or LNT) to make a TWNSC single component in the close coupled position, followed by an underbody NSC.…”

Section: Gasoline Gaseous Emissions Controlmentioning

confidence: 99%

“…Desulfation behavior of the front and back NOx storage catalysts match the heat-up properties of the system so the sulfur passes through the system. [110] Another lean-burn gasoline concept is to capture ammonia generated in the TWC during rich operation in a downstream SCR catalyst for use during lean operation. Parks [104] reported preliminary tests wherein the air:fuel ratio is oscillated between rich and lean.…”

Section: Gasoline Gaseous Emissions Controlmentioning

confidence: 99%

See 1 more Smart Citation

Vehicular Emissions in Review

Johnson¹

2014

SAE Int. J. Engines

139

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The review paper summarizes major developments in vehicular emissions regulations and technologies in 2013. First, the paper covers the key regulatory developments in the field, including proposed light-duty (LD) criteria pollutant tightening in the US; and in Europe, the continuing developments towards real-world driving emissions (RDE) standards. Significant shifts are occurring in China and India in addressing their severe air quality problems. The paper then gives a brief, high-level overview of key developments in fuels. Projections are that we are in the early stages of oil supply stability, which could stabilize fuel prices. LD and HD (heavy-duty) engine technology continues showing marked improvements in engine efficiency. Key developments are summarized for gasoline and diesel engines to meet both the emerging NOx and GHG regulations. HD engines are or will soon be demonstrating 50% brake thermal efficiency using common approaches. NOx control technologies are then summarized, including SCR (selective catalytic reduction) systems and SCR filter developments. Emphasis is on low-temperature deNOx and integration of components and control. Diesel PM (particulate matter) reduction technologies are evolving around the behavior of ash deposits and SCR integration. Filters for direct injection gasoline applications are developing very rapidly, and in some cases the back pressure, light-off characteristics, and emissions reductions are very similar to standard three way catalysts (TWCs). Oxidation catalysts mainly involve developments towards stubborn problems, like low-temperature performance with exhaust with high hydrocarbon and CO, and methane oxidation. Finally, the paper discusses some key developments in gasoline gaseous emission control, focusing on matching engine calibration with emissions system characteristics; and on lean burn gasoline emissions control.

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Section: Gasoline Gaseous Emissions Controlmentioning

confidence: 99%

Section: Gasoline Gaseous Emissions Controlmentioning

confidence: 99%

Vehicular Emissions in Review

Johnson¹

2014

SAE Int. J. Engines

139

View full text Add to dashboard Cite

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“…At high load, injection takes place during the intake stroke; the charge is homogeneous with stoichiometric mixtures. However, lean stratified operation has high particulate emissions [38], and needs lean-burn NO x aftertreatment to fulfill the legislative limits [29,39]. The regeneration of the NO x aftertreatment devices is achieved with rich operation that can increase PM emissions and fuel consumption so removing any efficiency benefits [40].…”

Section: Gasoline Engine Fundamentalsmentioning

confidence: 99%

European Regulatory Framework and Particulate Matter Emissions of Gasoline Light-Duty Vehicles: A Review

et al. 2019

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The particulate matter (PM) emissions of gasoline vehicles were much lower than those of diesel vehicles until the introduction of diesel particulate filters (DPFs) in the early 2000s. At the same time, gasoline direct injection (GDI) engines started to become popular in the market due to their improved efficiency over port fuel injection (PFI) ones. However, the PM mass and number emissions of GDI vehicles were higher than their PFI counterparts and diesel ones equipped with DPFs. Stringent PM mass levels and the introduction of particle number limits for GDI vehicles in the European Union (EU) resulted in significant PM reductions. The EU requirement to fulfill the proposed limits on the road resulted to the introduction of gasoline particulate filters (GPFs) in EU GDI models. This review summarizes the evolution of PM mass emissions from gasoline vehicles placed in the market from early 1990s until 2019 in different parts of the world. The analysis then extends to total and nonvolatile particle number emissions. Care is given to reveal the impact of ambient temperature on emission levels. The discussion tries to provide scientific input to the following policy-relevant questions. Whether particle number limits should be extended to gasoline PFI vehicles, whether the lower limit of 23 nm for particle number measurements should be decreased to 10 nm, and whether low ambient temperature tests for PM should be included.

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“…Lean-NOx aftertreatment, the need for which is a major factor in the development and introduction of SGSC engines into the marketplace, continues to be an area of significant activity. 117…”

Section: Sgsc Development Directionsmentioning

confidence: 99%

Invited Review: Combustion instability in spray-guided stratified-charge engines: A review

Fansler

Reuss

Sick

et al. 2015

International Journal of Engine Research

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This article reviews systematic research on combustion instabilities (principally rare, random misfires and partial burns) in spray-guided stratified-charge (SGSC) engines operated at part load with highly stratified fuel -air -residual mixtures. Results from high-speed optical imaging diagnostics and numerical simulation provide a conceptual framework and quantify the sensitivity of ignition and flame propagation to strong, cyclically varying temporal and spatial gradients in the flow field and in the fuel -air -residual distribution. For SGSC engines using multi-hole injectors, spark stretching and locally rich ignition are beneficial. Combustion instability is dominated by convective flow fluctuations that impede motion of the spark or flame kernel toward the bulk of the fuel, coupled with low flame speeds due to locally lean mixtures surrounding the kernel. In SGSC engines using outwardly opening piezo-electric injectors, ignition and early flame growth are strongly influenced by the spray's characteristic recirculation vortex. For both injection systems, the spray and the intake/compression-generated flow field influence each other. Factors underlying the benefits of multi-pulse injection are identified. Unresolved questions include (1) the extent to which piezo-SGSC misfires are caused by failure to form a flame kernel rather than by flame-kernel extinction (as in multi-hole SGSC engines); (2) the relative contributions of partially premixed flame propagation and mixing-controlled combustion under the exceptionally late-injection conditions that permit SGSC operation on E85-like fuels with very low NOx and soot emissions; and (3) the effects of flow-field variability on later combustion, where fuel-air-residual mixing within the piston bowl becomes important.

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Exhaust Gas Aftertreatment for Lean Gasoline Direct Injection Engines - Potential for Future Applications

Cited by 14 publications

References 4 publications

Vehicular Emissions in Review

Vehicular Emissions in Review

European Regulatory Framework and Particulate Matter Emissions of Gasoline Light-Duty Vehicles: A Review

Invited Review: Combustion instability in spray-guided stratified-charge engines: A review

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