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Technical Paper

Emissions Reduction Performance of a Bimetallic Platinum/Cerium Fuel Borne Catalyst with Several Diesel Particulate Filters on Different Sulfur Fuels

Results of engine bench tests on a 1998 heavy-duty diesel engine have confirmed the emissions reduction performance of a U.S. Environmental Protection Agency (EPA) registered platinum/cerium bimetallic fuel borne catalyst (FBC) used with several different catalyzed and uncatalyzed diesel particulate filters (DPF's). Performance was evaluated on both a 450ppm sulfur fuel (No.2 D) and a CARB 50ppm low sulfur diesel (LSD) fuel. Particulate emissions of less than 0.02g/bhp-hr were achieved on several combinations of FBC and uncatalyzed filters on 450ppm sulfur fuel while levels of 0.01g/bhp-hr were achieved for both catalyzed and uncatalyzed filters using the FBC with the low sulfur CARB fuel. Eight-mode steady state testing of one filter and FBC combination with engine timing changes produced a 20% nitrogen oxide (NOx) reduction with particulates (PM) maintained at 0.01g/bhp-hr and no increase in measured fuel consumption.
Technical Paper

Simultaneous Reduction of Diesel Particulate and NOx Using a Plasma

A non-thermal plasma treatment of diesel engine exhaust was effective in removing particulate (soot) and oxides of nitrogen (NOx) from two different light-duty diesel vehicles: an older-technology indirect-injection Toyota truck, and a newer-technology direct-injection Dodge truck. Particulate removal efficiencies and NOx conversion efficiencies were determined at space velocities up to 20,000/hr. Particulate removal efficiencies were above 60 percent for most conditions, but decreased with increasing space velocities. Conversion efficiencies for NOx and carbon monoxide (CO) were also dependent on the space velocity. The NOx conversion efficiencies were generally greater than 40 percent at space velocities less than 7000/hr. The CO concentration increased through the plasma reaction bed indicating that CO was produced by reactions in the plasma.
Technical Paper

Comparison of Exhaust Emissions from a Vehicle Fueled with Methanol-Containing Additives for Flame Luminosity

Two additive blends proposed for improving the flame luminosity in neat methanol fuel were investigated to determine the effect of these additives on the exhaust emissions in a dual-fueled Volkswagen Jetta. The two blends contained 4 percent toluene plus 2 percent indan in methanol and 5 percent cyclopentene plus 5 percent indan in methanol. Each blend was tested for regulated and unregulated emissions as well as a speciation of the exhaust hydrocarbons resulting from use of each fuel. The vehicle exhaust emissions from these two fuel blends were compared to the Coordinating Research Council Auto-Oil national average gasoline (RF-A), M100, and M85 blended from RF-A. Carter Maximum Incremental Reactivity Factors were applied to the speciated hydrocarbon emission results to determine the potential ozone formation for each fuel. Toxic emissions as defined in the 1990 Clean Air Act were also compared for each fuel.
Technical Paper

Countering the Effects of Media Interferences and Background Contamination in Collection of Low Concentration Aldehydes and Ketones in Engine Exhaust with Dinitrophenylhydrazine (DNPH) Derivatization

This paper discusses a method developed to counter the variability of media interferences for the measurement of aldehydes and ketones in automotive exhaust. Dinitrophenylhydrazine (DNPH) Derivatization Methodology for the collection of aldehyde and ketone compounds in vehicle exhaust has been in use for over thirty years. These carbonyl compounds are captured by passing diluted exhaust gas through a sample medium containing DNPH. The sampling medium can take the form of DNPH dispersed on a solid sorbent or as a DNPH solution in a solvent such as acetonitrile. Carbonyl compounds react readily to form DNPH derivatives which are stable and which absorb ultra-violet (UV) light, facilitating quantitative measurement. However, when the procedure was developed, emissions rates from vehicles were much higher than the current (2010) emissions levels.
Technical Paper

Comparison of Four Sampling Methods for Semi-volatile Organic Compounds in Gas Phase Diesel Engine Exhausts

Newly designed Teflon® O-rings along with XAD-2 resin, stainless steel screens, lock rings, and glass cartridges were used to construct a new semi-volatile organic compounds (SVOC's) sampling device. This new sampling device allows direct and repeated sampling, extraction, and cleaning without ever having to be disassembled or reassembled. This new XAD-2 glass cartridge (X2) was compared with three other sampling methods namely Empore® membrane (EM), hexane impinger (HI), and “Cold Trap” (CT) for SVOC sampling efficiency on diesel engine exhaust emissions. The X2 method showed the highest overall SVOC collection efficiency, followed by the EM and HI methods. The X2 method has higher trapping efficiency for the oxygenates, polycyclic aromatic hydrocarbons (PAH's), alkyl cyclohexanes, and the alkyl aromatics than the other three SVOC sampling methods. The HI method has the highest trapping efficiency for the normal alkanes.
Technical Paper

Sampling System Investigation for the Determination of Semi-Volatile Organic Compounds (SVOC) Emissions From Engine Exhaust

Semi-volatile organic compounds (SVOC) are a group of compounds that may form during combustion and/or are present in the unburned portion of the fuel and lubricating oil which ultimately become part of the exhaust. Many of these compounds are considered toxic or carcinogenic. Since these compounds are present in very low concentrations in diesel engine exhaust, the methods for sampling, handling, and analyzing these compounds are critical to obtaining representative and repeatable results. Engine testing is typically performed using a dilution tunnel. With a dilution tunnel, the collection of a representative sample is important. Experiments were performed with a modified EPA Method TO-9A to determine the equilibration time and other sampling parameters required for the measurement of SVOC in dilute exhaust. The results show that representative results can be obtained with this method.
Technical Paper

Dilute Measurement of Semi-Volatile Organic Compounds (SVOC) from a Heavy-Duty Diesel Engine

Semi-volatile organic compounds (SVOC) are a group of compounds in engine exhaust that either form during combustion or are part of the fuel and lubricating oil. Since these compounds occur at very low concentrations in diesel engine exhaust, the methods for sampling, handling, and analyzing these compounds are critical to obtaining good results. An improved dilute exhaust sampling method was used for sampling and analyzing SVOC in engine exhaust, and this method was performed during transient engine operation. A total of 22 different SVOC were measured using a 2012 medium-duty diesel engine. This engine was equipped with a stock diesel oxidation catalyst (DOC), a diesel particulate filter (DPF), and a selective catalytic reduction (SCR) catalyst in series. Exhaust concentrations for SVOC were compared both with and without exhaust aftertreatment. Concentrations for the engine-out SVOC were significantly higher than with the aftertreatment present.
Technical Paper

Comparison of Emissions and Fuel Economy Characteristics of Conventional, Additized, and Substantially Synthetic Diesel Fuels in a Heavy-Duty Diesel Engine

This study compared four different candidate fuels which were prepared by blending different components with a typical No. 2 diesel. Two fuels were blended with a synthetic diesel prepared from natural gas condensate, and all candidate fuels were splash blended with a proprietary additive package from International Fuel Technology Inc. (IFT). These fuels were then compared to the No. 2 diesel and to a California Air Resources Board (CARB) equivalent diesel fuel. The comparisons included fuel properties such as sulfur content, aromatics, cetane, lubricity, distillation; emissions; and fuel consumption. Emission testing was conducted on a 1991 Detroit Diesel Series 60. The Environmental Protection Agency (EPA) transient cycle was utilized for emissions, fuel characterization was performed according to ASTM standards, and fuel consumption was calculated by the carbon balance method.
Technical Paper

Comparison of Emission Characteristics of Conventional, Hydrotreated, and Fischer-Tropsch Diesel Fuels in a Heavy-Duty Diesel Engine

This study compared diesel exhaust emission from four different diesel fuels: a conventional low sulfur D2 diesel (0.03% sulfur, 28% aromatics), California Air Resources Board (CARB) diesel (0.015% sulfur, 8% aromatics), “Swedish” diesel (<0.001% sulfur, 4% aromatics), and a Fischer-Tropsch (F-T) diesel (<0.0001% sulfur, <0.1% aromatics) fuel. The comparison included regulated emissions, hydrocarbon speciation, air toxics, aldehydes and ketones, particle size distribution, and greenhouse gas emissions. Testing was conducted using a Cummins B-Series engine installed both in a heavy light-duty truck operating on a chassis dynamometer and on an engine dynamometer. The chassis driving cycles included city, highway, and aggressive driving operation. Engine dynamometer tests included the U.S. transient cycle.
Technical Paper

Experimental Investigation of the Scavenging Performance of a Two-Stroke Opposed-Piston Diesel Tank Engine

The Tank-Automotive RD&E Center periodically conducts foreign materiel evaluations to assess the current state of the art for ground vehicle technologies. The Propulsion Laboratory is conducting performance evaluations of an opposed-piston two-stroke diesel tank engine produced by the Kharkov Design Bureau in Ukraine. A key factor in the performance of all two-stroke engines is the scavenging process, which determines how well the cylinders are emptied of exhaust and filled with fresh air. The overall air flow rate is not sufficient to determine this, as a significant amount of air may be lost through the exhaust ports during the scavenging process. The inlet tracer gas method was employed to provide the additional data required. With methane as the tracer, it produced reasonable and consistent data over a wide range of engine speeds and loads. The inlet tracer gas method was found to be an effective tool for measuring the scavenging performance of a running two-stroke diesel engine.
Technical Paper

Laboratory Evaluation of Additives for Flame Luminosity Improvement in Neat Methanol Fuel

Neat methanol fuel (M100) has many advantages for achieving low emission levels as an automotive fuel, but there are several items that require attention before this fuel can replace conventional fuels. One item involves the low flame luminosity of methanol. An extensive literature search and laboratory evaluation were conducted to identify potential additive candidates to improve the luminosity of a methanol flame. Potential compounds were screened based on their concentration, luminosity improvement, and duration of luminosity improvement during the burn. Three compounds were found to increase the flame luminosity for segments of the burn at relatively low concentrations: toluene, cyclopentene, and indan. In combination, these three compounds markedly improved the luminosity of methanol throughout the majority of the burn. The two combinations were 1) 4 percent toluene plus 2 percent indan and 2) 5 percent cyclopentene plus 5 percent indan in methanol.
Technical Paper

Particulate Characterization Using Five Fuels

Particulate and regulated gaseous emissions were characterized in a feasibility study for a 1994 Ford Taurus Flexible Fuel Vehicle (FFV) operating on five fuels. The five fuels included Federal Reformulated Gasoline (RFG); 85% fuel grade methanol and 15% gasoline (M85); 85% denatured ethanol and 15% gasoline (E85d); liquefied petroleum gas (LPG) meeting HD-5 specifications; and industry average compressed natural gas (CNG). The vehicle was operated fuel-rich to simulate a vehicle operating condition leading to increased production of particulate matter. This simulation was accomplished by using a universal exhaust gas oxygen sensor (UEGO) in connection with an external controller. Appropriate aftermarket conversion kits involving closed-loop control and adaptive learning capabilities allowed operation on the gaseous fuels. Particulate emissions were characterized by total mass and particle size.
Technical Paper

Polycyclic Aromatic Hydrocarbons in Diesel Engine Exhaust Both with and without Aftertreatment

Since the conception of the internal combustion engine, smoky and ill-smelling exhaust was prevalent. Over the last century, significant improvements have been made in improving combustion and in treating the exhaust to reduce these effects. One group of compounds typically found in exhaust, polycyclic aromatic hydrocarbons (PAH), usually occurs at very low concentrations in diesel engine exhaust. Some of these compounds are considered carcinogenic, and most are considered hazardous air pollutants (HAP). Many methods have been developed for sampling, handling, and analyzing PAH. For this study, an improved method for dilute exhaust sampling was selected for sampling the PAH in diesel engine exhaust. This sampling method was used during transient engine operation both with and without aftertreatment to show the effect of aftertreatment.
Journal Article

Extension of Analytical Methods for Detailed Characterization of Advanced Combustion Engine Emissions

Advanced combustion strategies used to improve efficiency, emissions, and performance in internal combustion engines (IC) alter the chemical composition of engine-out emissions. The characterization of exhaust chemistry from advanced IC engines requires an analytical system capable of measuring a wide range of compounds. For many years, the widely accepted Coordinating Research Council (CRC) Auto/Oil procedure[1,2] has been used to quantify hydrocarbon compounds between C1 and C12 from dilute engine exhaust in Tedlar polyvinyl fluoride (PVF) bags. Hydrocarbons greater than C12+ present the greatest challenge for identification in diesel exhaust. Above C12, PVF bags risk losing the higher molecular weight compounds due to adsorption to the walls of the bag or by condensation of the heavier compounds. This paper describes two specialized exhaust gas sampling and analytical systems capable of analyzing the mid-range (C10 - C24) and the high range (C24+) hydrocarbon in exhaust.
Journal Article

Development of a Synthetic Diesel Exhaust

A two-phase study was performed to establish a standard diesel exhaust composition which could be used in the future development of light-duty diesel exhaust aftertreatment. In the first phase, a literature review created a database of diesel engine-out emissions. The database consisted chiefly of data from heavy-duty diesel engines; therefore, the need for an emission testing program for light- and medium-duty engines was identified. A second phase was conducted to provide additional light-duty vehicle emissions data from current technology vehicles. Engine-out diesel exhaust from four 2004 model light-duty vehicles with a variety of engine displacements was collected and analyzed. Each vehicle was evaluated using five steady-state engine operating conditions and two transient test cycles (the Federal Test Procedure and the US06). Regulated emissions were measured along with speciation of both volatile and semi-volatile components of the hydrocarbons.
Technical Paper

Impact of Ultra-Clean Fischer-Tropsch Diesel Fuel on Emissions in a Light Duty Passenger Car Diesel Engine

Sulfur and aromatic compounds in diesel fuel impact the emissions profile of current diesel engines. Fuels that do not contain these components can be made from natural gas using Fischer-Tropsch chemistry. Very little data has been presented comparing the emissions characteristics of current low sulfur diesel to fuels with ultra low levels of sulfur and aromatics in passenger car diesel engines. This study reports on an exhaust emission comparison of currently available conventional diesel fuel to Fischer Tropsch diesel fuel free of aromatics and sulfur comparisons included regulated emissions, air toxics, aldehydes and ketones, particle size distribution, and greenhouse gas emissions. Testing was conducted on a current model diesel passenger car using a chassis dynamometer. Regulated emissions were analyzed according to the Code of Federal Regulations (CFR) Title 40 specifications and requirements of the Environmental Protection Agency (EPA) Federal Test Procedure (FTP).