12 research outputs found
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Catalyzed Gasoline Particulate Filters Reduce Secondary Organic Aerosol Production from Gasoline Direct Injection Vehicles
The
effects of photochemical aging on exhaust emissions from two
light-duty vehicles with gasoline direct injection (GDI) engines equipped
with and without catalyzed gasoline particle filters (GPFs) were investigated
using a mobile environmental chamber. Both vehicles with and without
the GPFs were exercised over the LA92 drive cycle using a chassis
dynamometer. Diluted exhaust emissions from the entire LA92 cycle
were introduced to the mobile chamber and subsequently photochemically
reacted. It was found that the addition of catalyzed GPFs will significantly
reduce tailpipe particulate emissions and also provide benefits in
gaseous emissions, including nonmethane hydrocarbons (NMHC). Tailpipe
emissions composition showed important changes with the use of GPFs
by practically eliminating black carbon and increasing the fractional
contribution of organic mass. Production of secondary organic aerosol
(SOA) was reduced with GPF addition, but was also dependent on engine
design which determined the amount of SOA precursors at the tailpipe.
Our findings indicate that SOA production from GDI vehicles will be
reduced with the application of catalyzed GPFs through the mitigation
of reactive hydrocarbon precursors
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On-road gaseous and particulate emissions from GDI vehicles with and without gasoline particulate filters (GPFs) using portable emissions measurement systems (PEMS)
Black Carbon Emissions in Gasoline Exhaust and a Reduction Alternative with a Gasoline Particulate Filter
Black
carbon (BC) mass and solid particle number emissions were
obtained from two pairs of gasoline direct injection (GDI) vehicles
and port fuel injection (PFI) vehicles over the U.S. Federal Test
Procedure 75 (FTP-75) and US06 Supplemental Federal Test Procedure
(US06) drive cycles on gasoline and 10% by volume blended ethanol
(E10). BC solid particles were emitted mostly during cold-start from
all GDI and PFI vehicles. The reduction in ambient temperature had
significant impacts on BC mass and solid particle number emissions,
but larger impacts were observed on the PFI vehicles than the GDI
vehicles. Over the FTP-75 phase 1 (cold-start) drive cycle, the BC
mass emissions from the two GDI vehicles at 0 °F (−18
°C) varied from 57 to 143 mg/mi, which was higher than the emissions
at 72 °F (22 °C; 12–29 mg/mi) by a factor of 5. For
the two PFI vehicles, the BC mass emissions over the FTP-75 phase
1 drive cycle at 0 °F varied from 111 to 162 mg/mi, higher by
a factor of 44–72 when compared to the BC emissions of 2–4
mg/mi at 72 °F. The use of a gasoline particulate filter (GPF)
reduced BC emissions from the selected GDI vehicle by 73–88%
at various ambient temperatures over the FTP-75 phase 1 drive cycle.
The ambient temperature had less of an impact on particle emissions
for a warmed-up engine. Over the US06 drive cycle, the GPF reduced
BC mass emissions from the GDI vehicle by 59–80% at various
temperatures. E10 had limited impact on BC emissions from the selected
GDI and PFI vehicles during hot-starts. E10 was found to reduce BC
emissions from the GDI vehicle by 15% at standard temperature and
by 75% at 19 °F (−7 °C)
Effect of drive cycle and gasoline particulate filter on the size and morphology of soot particles emitted from a gasoline-direct-injection vehicle
The size and morphology of particulate matter emitted from a light-duty gasoline-direct-injection (GDI) vehicle, over the FTP-75 and US06 transient drive cycles, have been characterized by transmission-electron-microscope (TEM) image analysis. To investigate the impact of gasoline particulate filters on particulate-matter emission, the results for the stock-GDI vehicle, i.e., the vehicle in its original configuration, have been compared to the results for the same vehicle equipped with a catalyzed gasoline particulate filter (GPF). The stock-GDI vehicle emits graphitized fractal-like aggregates over all driving conditions. The mean projected area-equivalent diameter of these aggregates is in the 78.4\u201288.4 nm range and the mean diameter of primary particles varies between 24.6 and 26.6 nm. Post-GPF particles emitted over the US06 cycle appear to have an amorphous structure, and a large number of nucleation-mode particles, depicted as low-contrast ultrafine droplets, are observed in TEM images. This indicates the emission of a substantial amount of semivolatile material during the US06 cycle, most likely generated by the incomplete combustion of accumulated soot in the GPF during regeneration. The size of primary particles and soot aggregates does not vary significantly by implementing the GPF over the FTP-75 cycle; however, particles emitted by the GPF-equipped vehicle over the US06 cycle are about 20% larger than those emitted by the stock-GDI vehicle. This may be attributed to condensation of large amounts of organic material on soot aggregates. High-contrast spots, most likely solid nonvolatile cores, are observed within many of the nucleation-mode particles emitted over the US06 cycle by the GPF-equipped vehicle. These cores are either generated inside the engine or depict incipient soot particles which are partially carbonized in the exhaust line. The effect of drive cycle and the GPF on the fractal parameters of particles, such as fractal dimension and fractal prefactor, is insignificant.Peer reviewed: YesNRC publication: Ye
Characterization of real-time particle emissions from a gasoline direct injection vehicle equipped with a catalyzed gasoline particulate filter during filter regeneration
Real-time solid particle number (PN), size distributions, black carbon (BC), and particulate matter (PM) mass measurements were obtained from a gasoline direct injection (GDI) vehicle with and without a catalyzed gasoline particulate filter (GPF) over the US Federal Test Procedure 75 (FTP- 75) and US06 Supplemental Federal Test Procedure (US06) drive cycles. The organic and elemental carbon fractions of the carbonaceous PM and transmission electron microscope (TEM) images for the exhaust particles were examined. Particles emitted from the GDI vehicle over various moderate driving conditions have similar morphology, size, and composition. These accumulation mode particles have diameters of 50 to 90 nm, have comparable fractal structures to diesel particles, and contain mostly BC with little organic materials. Under aggressive driving conditions, many nanoparticles (<20 nm in diameter) are emitted with the accumulation mode particles. Over the FTP-75 driving conditions, the optimized GPF reaches particle filtration efficiency of over 90 % from clean condition rapidly and filtration efficiency remains unchanged as filter regeneration was not observed. Over the US06 driving condition, filter regeneration was triggered by the high exhaust temperature during which many nanoparticles with diameters smaller than 30 nm are formed downstream of the GPF. TEM image analysis suggests that BC particles collected during the filter regeneration contain a layer of semi-volatile materials on the aggregate surface while the nanoparticles were semi-volatile in nature.During filter regeneration, moderate filtration of the accumulation mode BC particles was still observed.Peer reviewed: YesNRC publication: Ye
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On-road gaseous and particulate emissions from GDI vehicles with and without gasoline particulate filters (GPFs) using portable emissions measurement systems (PEMS)
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Catalyzed Gasoline Particulate Filters Reduce Secondary Organic Aerosol Production from Gasoline Direct Injection Vehicles
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Gasoline Particulate Filters as an Effective Tool to Reduce Particulate and Polycyclic Aromatic Hydrocarbon Emissions from Gasoline Direct Injection (GDI) Vehicles: A Case Study with Two GDI Vehicles
Assessment of the Fuel Composition Impact on Black Carbon Mass, Particle Number Size Distributions, Solid Particle Number, Organic Materials, and Regulated Gaseous Emissions from a Light-Duty Gasoline Direct Injection Truck and Passenger Car
The influence of
the aromatic hydrocarbons in gasoline on the fuel
distillation parameter, as well as the particle number (PN), black
carbon (BC), and other regulated gaseous emissions from a passenger
car (PC) and light-duty truck (LDT), was assessed by operating two
vehicles fueled with U.S. Environmental Protection Agency Tier 3 certification
gasoline and two gasoline test fuels over two standard drive cycles.
The two gasoline test fuels represent a range of commercial motor
gasoline, with one containing less naphthalenes and lower heavy fraction
volatility (T80, T90, and final boiling point) than the other. Observations
showed that various gasolines have minor impact on both vehicles on
regulated gaseous emissions and fuel consumption. Particulate emissions
from both vehicles showed similar trends with fuel type, with lower
naphthalene containing gasoline produced lower PN and BC emissions.
In addition, the effect of fuel on particle emissions varied with
vehicle type, drive cycle, and power to weight ratio. Results also
showed that lowering the naphthalenes in gasoline produces smaller
sized particles. The real-time particle emission time series from
both vehicles suggested that the composition and volatility of the
gasoline fuels are sensitive parameters in influencing particulate
matter emissions. These results could support one possible explanation
of the large variations in emission factors reported in the literature
when using different gasolines in the same type of vehicle and driving
conditions