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This program involved the detailed evaluation of a novel laser-based in-exhaust ammonia sensor using a diesel fuel-based burner platform integrated with an ammonia injection system. Test matrix included both steady-state modes and transient operation of the burner platform. Steady-state performance evaluation included tests that examined impact of exhaust gas temperature, gas velocity and ammonia levels on sensor response. Furthermore, cross sensitivity of the sensor was examined at different levels of NOX and water vapor. Transient tests included simulation of the FTP test cycles at different ammonia and NOX levels. A Fourier transform infrared (FTIR) spectrometer as well as NIST traceable ammonia gas bottles (introduced into the exhaust stream via a calibrated flow controller) served as references for ammonia measurement.

Southwest Research Institute (SwRI) utilizes the burner-based Exhaust Composition Transient Operation LaboratoryTM (ECTO-Lab) to accurately simulate transient engines and replicate real exhaust that is produced by light and heavy-duty engines for aftertreatment aging and evaluations. This system can generate and dose NOX over transient cycles from a range of 20 ppm to 1200 ppm where the NOX is generated by the in-situ decomposition and combustion of a fuel-bound, nitrogen containing compound. During the combustion and decomposition of the nitrogen containing compound over 95 % of the NOX generated is in the form of NO. To authentically simulate exhaust gases, it is necessary to account for the distribution of the NO to the NO2. Since previous work has established that the decomposition of nitric acid can be utilized as a method to generate NO2, the objective of this project was to develop control of NO and NO2 within SwRI’s ECTO-Lab through the decomposition of nitric acid.

Sustained NOx reduction at low temperatures, especially in the 150-200 °C range, shares some similarities with the more commonly discussed cold-start challenge, however, poses a number of additional and distinct technical problems. In this project, we set a bold target of achieving and maintaining 90% NOx conversion at the SCR catalyst inlet temperature of 150 °C. This project is intended to push the boundaries of the existing technologies, while staying within the realm of realistic future practical implementation. In order to meet the resulting challenges at the levels of catalyst fundamentals, system components, and system integration, Cummins has partnered with the DOE, Johnson Matthey, and Pacific Northwest National Lab and initiated the Sustained Low-Temperature NOx Reduction program at the beginning of 2015 and completed in 2017.

Copper- and Iron- based metal-zeolite SCR catalysts are widely used in US and European diesel aftertreatment systems to achieve drastic reduction in NOx emission. These catalysts are highly selective to N2 under wide range of operating conditions. Nevertheless, the type of transition metal has a significant impact on the key performance and durability parameters such as NOx conversion, selectivity towards N2O, hydrothermal stability, and sensitivity to fuel sulfur content. In this study, we explained the differences in the performance characteristics of these catalysts based on their relative acidic-basic nature of transition metal present in these catalysts using practically relevant gas species present in diesel exhaust such as NO2, SOx, and NH3. These experiments show that Fe-zeolite has relatively acidic nature as compared to Cu-zeolite that causes NH3 inhibition and hence explains low NOx conversion on Fe-zeolite at low temperature under standard SCR conditions.

Cu/CHA catalysts have been widely used in the industry, due to their desirable performance characteristics including the unmatched hydrothermal stability. While broadly recognized for their outstanding activity at or above 200°C, these catalysts may not show desired levels of NOx conversion at lower temperatures. To achieve high NOx conversions it is desirable to have NO2/NOx close to 0.5 for fast SCR. However even under such optimal gas feed conditions, sustained use of Cu/CHA below 200°C leads to ammonium nitrate formation and accumulation, resulting in the inhibition of NOx conversion. In this contribution, the formation and decomposition of NH4NO3 on a commercial Cu/CHA catalyst have been investigated systematically. First, the impact of NH4NO3 self-inhibition on SCR activity as a function of temperature and NO2/NOx ratios was investigated through reactor testing.

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.

The engine intake process governs many aspects of the flow within the cylinder. The inlet valve is the minimum area, so gas velocities at the valve are the highest velocities seen. Geometric configuration of the inlet ports and valves, and the opening schedule create organized large scale motions in the cylinder known as swirl and tumble. Good charge motion within the cylinder will produce high turbulence levels at the end of the compression stroke. As the turbulence resulting from the conversion energy of the inlet jet decays fast, the strategy is to encapsulate some of the inlet jet in the organized motions. In this work the baseline port of a 2.0 L gasoline engine was modified by inserting a tumble plate. The work was done in support of an experimental study for which a new single-cylinder research engine was set up to allow combustion system parameters to be varied in steps over an extensive range. Tumble flow was one such parameter.

The presented work describes how spark calorimeter testing was used for parametric study and secondary circuit model calibration. Tests were conducted at different pressures, sparkplug gaps and supplied primary energies. The conversion efficiency increases and the spark duration decreases when the gas pressure or the sparkplug gap size is increased. Both gas pressure and sparkplug gas size increase the positive column voltage which represents part of the electrical energy delivered to the gas. The opposite direction occurs when the supplied primary energy is increased. The testing results were then used to calibrate the secondary circuit model which consisted of the sparkplug, the sparkplug gap and the secondary wiring. A step-by-step method was used to calibrate the three constants of the model to match the calculated delivered energy with test data during arc / glow phase.

Accurate estimation of catalyst bed temperatures is very crucial for effective control and diagnostics of aftertreatment systems. The architecture of most aftertreatment systems contains temperature sensors for measuring the exhaust gas temperatures at the inlet and outlet of the aftertreatment systems. However, the temperature that correctly reflects the temperature of the chemical reactions taking place on the catalyst surface is the catalyst bed temperature. From the Arrhenius relationship which governs the chemical reaction kinetics occurring in different aftertreatment systems, the rate of chemical reaction is very sensitive to the reaction temperature. Considerable changes in tailpipe emissions can result from small changes in the reaction temperature and robust emissions control systems should be able to compensate for these changes in reaction temperature to achieve the desired tailpipe emissions.

A solid particle number measurement system (SPNMS) was developed using a catalytic stripper (CS) technology instead of an evaporation tube (ET). The ET is used in commercially available systems, compliant with the Particle Measurement Program (PMP) protocol developed for European Union (EU) solid particle number regulations. The catalytic stripper consists of a small core of a diesel exhaust oxidation catalyst. The SPNMS/CS met all performance requirements under the PMP protocol. It showed a much better performance in removing large volatile tetracontane particles down to a size well below the PMP lower cut-size of 23 nm, compared to a SPNMS equipped with an ET instead of a CS. The SPNMS/CS also showed a similar performance to a commercially available system when used on a gasoline direct injection (GDI) engine exhaust.

This paper summarizes the validation testing of the Horiba Instruments OBS-2200 gaseous portable emissions measurement system (PEMS) for in-use compliance testing per Title 40 of the Code of Federal Regulations (CFR) Part 1065.920 (Section 1065.920). The qualification process included analyzer verifications as well as engine testing on a model-year 2007 heavy-duty diesel engine produced by Volvo Powertrain. The measurements of brake-specific emissions with the OBS-2200 were compared to those of a CFR Part 1065-compliant CVS test cell over a series of not-to-exceed (NTE) events. The OBS-2200 passed all linearity verifications and analyzer checks required of PEMS. Engine test validation was achieved for all three regulated gaseous emissions (CO, NMHC, and NOX) per 40 CFR Part 1065.920(b)(5)(i), which requires a minimum of 91 percent of the measurement allowance adjusted deltas to be less than or equal to zero.

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.

Previously we reported (SAE Paper 2005-01-0475) that emissions of toxicologically relevant compounds from an engine operating at low NOx conditions using Fischer-Tropsch fuel (FT100) were lower than those emissions from the engine using an ultra-low sulfur (15 PPM sulfur) diesel fuel (BP15). Those tests were performed at two operating modes: Mode 6 (4.2 bar BMEP, 2300 RPM) and Mode 11 (2.62 bar BMEP, 1500 RPM). We wanted to evaluate the effect on emissions of operating the engine at low power (near idle) in conjunction with the low NOx strategy. Specifically, we report on emissions of total hydrocarbon (HC), carbon monoxide (CO), NOx, particulates (PM), formaldehyde, acetaldehyde, benzene, 1,3-butadiene, gas phase polyaromatic hydrocarbons (PAH's) and particle phase PAH's from a DaimlerChrysler OM611 CIDI engine using a low NOx engine operating strategy at Mode 22 (1.0 bar BMEP and 1500 RPM).

This paper examines the role of inhalation toxicity of the products of combustion that are generated in post-collision motor vehicle fires by automotive materials used under the hood. Small-scale toxic gas measurements were performed at Southwest Research Institute® (SwRI®) on eighteen components of two of the vehicles that were tested previously at the Factory Mutual Test Center (FMTC). The small-scale toxic gas measurements were obtained under dynamic flow-through conditions in the Cone Calorimeter (ASTM E 1354) and under static conditions in two smoke chamber methods (ASTM E 662 and ASTM E 1995); all methods were supplemented with FTIR gas analysis. Average yields of toxic gases measured in the Cone Calorimeter are comparable to but consistently lower than values reported in the literature for the Fire Propagation Apparatus (ASTM E 2058).

Particle size distribution, number, and mass emissions from the exhaust of a 92 kW 1999 Isuzu 6BG1 nonroad naturally aspirated diesel engine were measured. The engine exhaust was equipped with a Dry System Technologies® (DST) auxiliary emission control device that included an oxidation catalyst, a heat exchanger, and a disposable paper particulate filter. Particle measurement was taken during the ISO 8178 8-mode test for engine out and engine with the DST using a scanning mobility particle sizer (SMPS) in parallel to the standard filter method (SFM), specified in 40 CFR, Part 89. The DST efficiency of removing particles was about 99.9 percent based on particle number, 99.99 percent based on particle mass derived from number and size. However, the efficiency based on mass derived from the SFM was much lower on the order of 90 to 93 percent.

Lower explosion limits (LEL) and the chemical compositions of JP-8, Jet A and JP-5 fuel vapors were determined in a sealed combustion vessel equipped with a spark igniter, a gas-sampling probe, and sensors to measure pressure rise and fuel temperature. Ignition was detected by pressure rise in the vessel. Pressure rises up to 60 psig were observed near the flash points of the test fuels. The fuel vapors in the vessel ignited from as much as 11°F below flash-point measurements. Detailed hydrocarbon speciation of the fuel vapors was performed using high-resolution gas chromatography. Over 300 hydrocarbons were detected in the vapors phase. The average molecular weight, hydrogen to carbon ratio, and LEL of the fuel vapors were determined from the concentration measurements. The jet fuel vapors had molecular weights ranging from 114 to 132, hydrogen to carbon ratios of approximately 1.93, and LELs comparable to pure hydrocarbons of similar molecular weight.

High-speed movie films, and laser-diffraction drop sizing were used to evaluate the structure, penetration rate, cone angle, and drop size distribution of diesel sprays in a constant volume pressure vessel. As further means of evaluating the data, comparisons are made between the film measurements, and calculations from a dense gas jet model. In addition to the high-speed film data that describes the overall structure of the spray as a function of time, a laser diffraction instrument was used to measure drop size distribution through a cross-section of the spray. In terms of the growth of the total spray volume (a rough measure of the amount of air entrained in the spray), spray impingement causes an initial delay, but generally the same overall growth rate as an equivalent unimpeded spray. Agreement between measurements and calculations is excellent for a diesel spray with a 0.15 mm D orifice and relatively high injection pressures.

A technique is presented that has been successfully demonstrated to non-intrusively and quickly sample gases typically found in PCV systems. Color Detection Tubes (CDTs) were used with a simple sampling arrangement to monitor CO2, NOx, O2, and H2O(g) at the closure line, crankcase, and PCV line. Measurements were accurate and could be made instantaneously. Short Path Thermal Desorbtion Tubes (SPTDTs) were used at the same engine locations for the characterization of fuel- and oil-derived hydrocarbon (HC) fractions and required only 50 cc samples. High engine loads caused pushover of blowby vapors as indicated by increased concentrations of CO2, NOx, H2O(g), and fuel HCs in the engines' fresh air inlets during WOT operation. Peak concentrations of blowby vapors were measured in the crankcase under no load and part throttle conditions. Oxygen concentrations always opposed the trends of CO2, NOx, and H2O(g).

Regulated gaseous, particulate and several unregulated emissions are reported from four heavy-duty diesel engines operated on the chassis version of the 1983 transient procedure. Emissions were obtained from Caterpillar 3208, Mack ENDT 676, Cummins Formula 290 and Detroit Diesel 8V-71 engines with several diesel fuels. A large dilution tunnel (57′ × 46″ ID) was fabricated to allow total exhaust dilution, rather than the double dilution employed in the stationary engine version of the transient procedure. A modal particulate sampler was developed to obtain particulate data from the individual segments of the 1983 transient procedure. The exhaust gas was analyzed for benzo(a)pyrene, metals, N2O, NO2, individual hydrocarbons and HCN. Sequential extractions were performed and measured versus calculated fuel consumptions were obtained.

This paper discusses the techniques and diagnostic significance of atomic absorption, atomic emission, and infrared spectrometric analysis of crankcase lubricants, with the use of supplementary data where pertinent. The parameters affecting used oil analytical data are discussed in terms of examples from Army general purpose vehicle test engines. Wear metals in used gear oils are also discussed and examples are given. Analytical methods and their applications are fully described, and the equipment and procedures for infrared spectroscopy and gas chromatography techniques are outlined.