Ultrafine PM Emissions from Natural Gas, Oxidation-Catalyst Diesel, and Particle-Trap Diesel Heavy-Duty Transit Buses

2002 ◽  
Vol 36 (23) ◽  
pp. 5041-5050 ◽  
Author(s):  
Britt A. Holmén ◽  
Alberto Ayala
Keyword(s):  
Natural Gas ◽  
Oxidation Catalyst ◽  
Heavy Duty ◽  
Transit Buses ◽  
Particle Trap

Effect of an economical oxidation catalyst formulation on regulated and unregulated pollutants from natural gas fueled heavy duty transit buses

2011 ◽  
Vol 16 (6) ◽  
pp. 469-473 ◽  
Author(s):  
Arvind Thiruvengadam ◽  
Daniel K. Carder ◽  
Mohan Krishnamurthy ◽  
Adewale Oshinuga ◽  
Mridul Gautam
Keyword(s):  
Natural Gas ◽  
Oxidation Catalyst ◽  
Heavy Duty ◽  
Transit Buses ◽  
Gas Fueled

Development of an Advanced Retrofit Aftertreatment System Targeting Toxic Air Contaminants and Particulate Matter Emissions From HD-CNG Engines

2010 ◽  
Author(s):  
Hemanth Kappanna ◽  
Marc C. Besch ◽  
Daniel K. Carder ◽  
Mridul Gautam ◽  
Adewale Oshinuga ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Natural Gas ◽  
Exhaust Aftertreatment ◽  
Heavy Duty ◽  
Air Contaminants ◽  
Number Count ◽  
Transit Buses ◽  
Order Of Magnitude ◽  
Toxic Air Contaminants ◽  
In Transit

Increasing urban pollution levels have led to the imposition of evermore stringent emissions regulations on heavy-duty engines used in transit buses. This has made compressed natural gas (CNG) a promising fuel for reducing emissions, particularly particulate matter (PM) from heavy-duty transit buses. Indeed, research studies performed at West Virginia University (WVU) and elsewhere have shown that pre-2010 compliant natural gas engines emit an order of magnitude lower PM emissions, on a mass basis, when compared to diesel engines without any exhaust aftertreatment devices. However, on a number basis, particle emissions in the nanoparticulate range were an order of magnitude higher for natural gas fueled buses than their diesel counterparts. There exists a significant number of pre-2007 CNG powered buses in transit agencies in the US and elsewhere in the world. Therefore, an exhaust aftertreatment device was designed and developed by WVU, in association with Lubrizol, to retrofit urban transit buses powered by MY2000 Cummins Westport C8.3G+ heavy-duty CNG engines, and effectively reduce Toxic Air Contaminants (TAC) and PM (mass and number count) exhaust emissions. The speciation results showed that the new exhaust aftertreatment device reduced emissions of metallic elements such as iron, zinc, nonmetallic minerals such as calcium, phosphorus and sulfur derived from lube oil additives to non-detectable levels, which otherwise could contribute to an increase in number count of nanoparticles. The carbonyl compounds were reduced effectively by the oxidation catalyst to levels below what were found in the dilution air. Also, hydrocarbons identified as TAC’s by California Air Resource Board (CARB) [1] were reduced to non-detectable levels. This ultimately reduced the number of nanoparticles to levels equal to that found in the dilution air.

Emissions of Toxic Pollutants from Compressed Natural Gas and Low Sulfur Diesel-Fueled Heavy-Duty Transit Buses Tested over Multiple Driving Cycles

2005 ◽  
Vol 39 (19) ◽  
pp. 7638-7649 ◽  
Author(s):  
Norman Y. Kado ◽  
Robert A. Okamoto ◽  
Paul A. Kuzmicky ◽  
Reiko Kobayashi ◽  
Alberto Ayala ◽  
...  
Keyword(s):  
Natural Gas ◽  
Heavy Duty ◽  
Compressed Natural Gas ◽  
Toxic Pollutants ◽  
Driving Cycles ◽  
Transit Buses ◽  
Low Sulfur

scholarly journals Microstructural Characteristics of Vehicle-Aged Heavy-Duty Diesel Oxidation Catalyst and Natural Gas Three-Way Catalyst

Catalysts ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 137 ◽  
Author(s):  
Tomi Kanerva ◽  
Mari Honkanen ◽  
Tanja Kolli ◽  
Olli Heikkinen ◽  
Kauko Kallinen ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Natural Gas ◽  
Photoelectron Spectroscopy ◽  
Real Life ◽  
Diesel Oxidation Catalyst ◽  
Oxidation Catalyst ◽  
Heavy Duty ◽  
X Ray ◽  
Ageing Effects ◽  
Diesel Oxidation

Techniques to control vehicle engine emissions have been under increasing need for development during the last few years in the more and more strictly regulated society. In this study, vehicle-aged heavy-duty catalysts from diesel and natural gas engines were analyzed using a cross-sectional electron microscopy method with both a scanning electron microscope and a transmission electron microscope. Also, additional supporting characterization methods including X-ray diffractometry, X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy and catalytic performance analyses were used to reveal the ageing effects. Structural and elemental investigations were performed on these samples, and the effect of real-life ageing of the catalyst was studied in comparison with fresh catalyst samples. In the real-life use of two different catalysts, the poison penetration varied greatly depending on the engine and fuel at hand: the diesel oxidation catalyst appeared to suffer more thorough changes than the natural gas catalyst, which was affected only in the inlet part of the catalyst. The most common poison, sulphur, in the diesel oxidation catalyst was connected to cerium-rich areas. On the other hand, the severities of the ageing effects were more pronounced in the natural gas catalyst, with heavy structural changes in the washcoat and high concentrations of poisons, mainly zinc, phosphorus and silicon, on the surface of the inlet part.

Unregulated Emissions from Compressed Natural Gas (CNG) Transit Buses Configured with and without Oxidation Catalyst

2006 ◽  
Vol 40 (1) ◽  
pp. 332-341 ◽  
Author(s):  
Robert A. Okamoto ◽  
Norman Y. Kado ◽  
Paul A. Kuzmicky ◽  
Alberto Ayala ◽  
Reiko Kobayashi
Keyword(s):  
Natural Gas ◽  
Oxidation Catalyst ◽  
Compressed Natural Gas ◽  
Transit Buses ◽  
Unregulated Emissions

Experimental Investigation of a Heavy-Duty Compression-Ignition Engine Retrofitted to Natural Gas Spark-Ignition Operation

2019 ◽  
Vol 141 (11) ◽  
Author(s):  
Jinlong Liu ◽  
Hemanth Kumar Bommisetty ◽  
Cosmin Emil Dumitrescu
Keyword(s):  
Natural Gas ◽  
Spark Ignition ◽  
Operating Conditions ◽  
Compression Ignition ◽  
Heavy Duty ◽  
Compression Ignition Engine ◽  
Engine Operation ◽  
Cycle Variation ◽  
Spark Timing ◽  
Ci Engines

Heavy-duty compression-ignition (CI) engines converted to natural gas (NG) operation can reduce the dependence on petroleum-based fuels and curtail greenhouse gas emissions. Such an engine was converted to premixed NG spark-ignition (SI) operation through the addition of a gas injector in the intake manifold and of a spark plug in place of the diesel injector. Engine performance and combustion characteristics were investigated at several lean-burn operating conditions that changed fuel composition, spark timing, equivalence ratio, and engine speed. While the engine operation was stable, the reentrant bowl-in-piston (a characteristic of a CI engine) influenced the combustion event such as producing a significant late combustion, particularly for advanced spark timing. This was due to an important fraction of the fuel burning late in the squish region, which affected the end of combustion, the combustion duration, and the cycle-to-cycle variation. However, the lower cycle-to-cycle variation, stable combustion event, and the lack of knocking suggest a successful conversion of conventional diesel engines to NG SI operation using the approach described here.

Low Emissions Class 8 Heavy-Duty On-Highway Natural Gas and Gasoline Engine

2004 ◽  
Author(s):  
James P. Chiu ◽  
James Wegrzyn ◽  
Kenneth E. Murphy
Keyword(s):  
Natural Gas ◽  
Gasoline Engine ◽  
Heavy Duty
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