Soot Emission Reduction from Post Injection Strategies in a High Pressure Direct-Injection Natural Gas Engine

Faghani, Ethan; Patychuk, Bronson; McTaggart-Cowan, Gordon; Rogak, Steven N.

doi:10.4271/2013-24-0114

Cited by 15 publications

(4 citation statements)

References 12 publications

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“…In the closed-loop control strategy, ammonia slip from the first SCR catalyst provides feedback into the urea injection controller [63]. This allows the first catalyst to have close to maximum NH 3 storage to facilitate both cold start application [59] and improved SCR kinetics [64]. The ammonia slip response times are much faster, potentially allowing higher NH 3 :NOx injection ratios for higher efficiency, without more ammonia slip.…”

Section: Scrmentioning

confidence: 99%

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: Scrmentioning

confidence: 99%

Vehicular Emissions in Review

Johnson¹

2014

SAE Int. J. Engines

139

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“…A smaller improvement in PM emissions is possible with no NOx cost. Faghani et al (2013) also investigated methods of reducing PM levels from this engine. They determined that a split gas injection strategy where 15-20% of the natural gas is injected 1.5-2.5 ms after the end of the first injection can reduce PM and CO emissions by 80%.…”

Section: Introductionmentioning

confidence: 99%

Characterization of Particulate Matter Morphology and Volatility from a Compression-Ignition Natural-Gas Direct-Injection Engine

Graves

Olfert

Patychuk³

et al. 2015

Aerosol Science and Technology

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The particulate matter (PM) emitted from a single-cylinder compression-ignition, natural-gas engine fitted with a HighPressure Direct-Injection (HPDI) system distinctly different from a duel fuel engine was investigated, and characterized by size distribution, morphology, mass-mobility exponent, effective density, volatility, mixing state, and primary particle size using transmission electron microscopy (TEM), and tandem measurements from differential mobility analyzers (DMA) and a centrifugal particle mass analyzer (CPMA). Six engine conditions were selected with varying load, speed, exhaust gas recirculation (EGR) fraction, and fuel delivery strategy. An increase in engine load increased both the number concentration and the geometric mean diameter of the particulate. The fraction of the number of purely volatile particles to total number of particles (number volatile fraction, NVF) was found to decrease as load increased, although at the lower speed, partially premixed mode, the lowest NVF. All size distributions were also found to be unimodal. The size-segregated ratio of the mass of internally mixed volatile material to total particle mass (mass volatile fraction, MVF) decreased with load and with particle mobility-equivalent diameter. A roughly constant amount of volatile material is likely produced at each engine mode, and the decrease in MVF is due to the increase in PM number with load. Effective density and massmobility exponent of the non-volatile soot at the different engine loads were the same or slightly higher than soot from traditional diesel engines. Denuded effective density trends were observed to collapse to approximately the same line, although engine modes with higher MVFs had slightly higher effective densities suggesting that the soot structures have collapsed into more dense shapes-a suspicion that is confirmed with TEM images. TEM results also indicated that primary particle size first decreases from low to medium load, then increases from medium to high load. An increase in EGR was also seen to increase primary particle size. Coefficients were determined for a relation that gives primary particle diameter as a function of projected area equivalent diameter. A decrease in load or speed results in a stronger correlation.

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“…[2][3][4] The most common form of ignition assist has been to use two fuels, typically diesel fuel along with natural gas, in either a ''Dual-Fuel'' approach 2,[5][6][7][8][9] or a High Pressure Direct Injection (HPDI) technique. [10][11][12][13][14] Nevertheless, the use of the small amount of diesel fuel increases the engine emissions, especially particulate matter (PM) emissions. [15][16][17] Forms of ignition assist other than the use of a diesel pilot spray can be employed.…”

Section: Introductionmentioning

confidence: 99%

Soot and combustion models for direct-injection natural gas engines

Pan

Wallace

2020

International Journal of Engine Research

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This paper summarizes the validation of a modified multi-step phenomenological soot model and an enhanced combustion model used for direct-injection natural gas engines. In this study, a modified phenomenological soot model including the key steps for soot formation, such as particle inception and surface growth, was developed in KIVA-3V to replace the empirical model for use in a glow plug assisted natural gas direct-injection engine. The soot model was integrated with a CANTERA based kinetic model, which employs a recently developed low temperature natural gas mechanism to predict the reactions of some important gaseous species involved in the soot formation, such as acetylene and hydroxyl. The simulated in-cylinder flame propagation process induced by a glow plug was compared to the experimental optical images obtained in an engine-like environment. In addition, both the kinetic model and modified soot model were compared with the experimental emission data to validate their reliability for predicting natural gas engine emission characteristics. The engine combustion efficiencies obtained in simulations and experiments were compared as well. The matched results suggest that the computational models can well predict the natural gas combustion and emission characteristics, and will be suitable for investigating the direct-injection natural gas engine technologies.

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Soot Emission Reduction from Post Injection Strategies in a High Pressure Direct-Injection Natural Gas Engine

Cited by 15 publications

References 12 publications

Vehicular Emissions in Review

Vehicular Emissions in Review

Characterization of Particulate Matter Morphology and Volatility from a Compression-Ignition Natural-Gas Direct-Injection Engine

Soot and combustion models for direct-injection natural gas engines

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