Comparison of Exhaust Emissions, Including Toxic Air Contaminants, from School Buses in Compressed Natural Gas, Low Emitting Diesel, and Conventional Diesel Engine Configurations

The present study surveys the effects on performance and emission parameters of a partially modified single cylinder direct injection (DI) diesel engine fueled with diesohol blends under varying compressed natural gas (CNG) flowrates in dual fuel mode. Based on experimental data, an artificial intelligence (AI) specialized artificial neural network (ANN) model have been developed for predicting the output parameters, viz. brake thermal efficiency (Bth), brake-specific energy consumption (BSEC) along with emission characteristics such as oxides of nitrogen (NOx), unburned hydrocarbon (UBHC), carbon dioxide (CO2), and carbon monoxide (CO) emissions. Engine load, Ethanol share, and CNG strategies have been used as input parameters for the model. Among the tested models, the Levenberg–Marquardt feed-forward back propagation with three input neurons or nodes, two hidden layers with ten neurons in each layer and six output neurons, and tansig-purelin activation function have been found to the optimal model topology for the diesohol–CNG platforms. The statistical results acquired from the optimal network topology such as correlation coefficient (0.992–0.999), mean square error (MSE) (0.0001–0.0009), and mean absolute percentage error (MAPE) (0.09–2.41%) along with Nash–Sutcliffe coefficient of efficiency (NSE), Kling–Gupta efficiency (KGE), mean square relative error, and model uncertainty established itself as a real-time robust type machine learning tool under diesohol–CNG paradigms. The study also incorporated a special type of measure, namely Pearson's Chi-square test or goodness of fit, which brings up the model validation to a higher level.

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A Review on Knock Phenomena in CNG-Diesel Dual Fuel System

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.773-774.550 ◽

2015 ◽

Vol 773-774 ◽

pp. 550-554 ◽

Cited By ~ 1

Author(s):

Fathul Hakim Zulkifli ◽

Mas Fawzi ◽

Shahrul Azmir Osman

Keyword(s):

Diesel Engine ◽

Natural Gas ◽

Dual Fuel ◽

Basic Operation ◽

Fuel System ◽

Compressed Natural Gas

The compressed natural gas (CNG) – diesel dual fuel engine is discussed through their basic operation and its characteristic. The main problem of running a diesel engine on dual fuel mode with CNG as main fuel is addressed. A brief review of knock phenomena which is widely associated with a dual fuel engine is also covered. Methods to suppress onset knock were suggested.

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

ASME 2010 Internal Combustion Engine Division Fall Technical Conference ◽

10.1115/icef2010-35131 ◽

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.

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The Potential for the Use of Natural Gas and Propane As Alternative Fuels in the Marine Industry

ASME/USCG 2013 3rd Workshop on Marine Technology and Standards ◽

10.1115/mts2013-0305 ◽

2013 ◽

Author(s):

Par Neiburger

Keyword(s):

Diesel Engine ◽

Natural Gas ◽

Alternative Fuels ◽

Alternative Fuel ◽

Liquefied Natural Gas ◽

Road Vehicles ◽

Compressed Natural Gas ◽

Gaseous Fuels ◽

Diesel Vehicles ◽

Marine Industry

Liberator Engine Company, LLC designs, develops and produces alternative fuel engines for vehicles around the globe. The Company’s 6.0 Liter Liberator™ gaseous fuels engine will have the ability to operate on Compressed Natural Gas, Liquefied Natural Gas or Liquid Propane Gas: clean, domestic, economical fuels. The Liberator engine will target OEM on road vehicles, as well as off road applications. The Liberator engine is also an excellent choice for the repower of existing diesel vehicles. The 6.0L Liberator™ engine will serve as a replacement engine for vehicle currently operating on a Cummins 5.9L diesel engine or Mercedes diesel 6.0L engine. Paper published with permission.

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