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A work-based window method has been developed to calculate in-use brake-specific oxides of nitrogen (NOx) emissions for all engine speeds and engine loads. During an in-use test, engine speed and engine torque are read from the engine's electronic control unit, and along with time, are used to determine instantaneous engine power. Instantaneous work is calculated using this power and the time differential in the data collection. Work is then summed until the target amount of work is accumulated. The emissions levels are then calculated for that window of work. It was determined that a work window equal to the theoretical Federal Test Procedure (FTP) cycle work best provides a means of comparison to the FTP certification standard. Also, a failure criterion has been established based on the average amount of power generated in the work window and the amount of time required to achieve the target work window to determine if a particular work window is valid.

As part of the 1998 Consent Decrees concerning alternative ignition strategies between the six settling heavy-duty diesel engine manufacturers and the United States government, the engine manufacturers agreed to perform in-use emissions measurements of their engines. As part of the Consent Decrees, pre- (Phase III, pre-2000 engines) and post- (Phase IV, 2001 to 2003 engines) Consent Decree engines used in over-the-road vehicles were tested to examine the emissions of oxides of nitrogen (NOx) and carbon dioxide (CO2). A summary of the emissions of NOx and CO2 and fuel consumption from the Phase III and Phase IV engines are presented for 30 second “Not-to-Exceed” (NTE) window brake-specific values. There were approximately 700 Phase III tests and 850 Phase IV tests evaluated in this study, incorporating over 170 different heavy duty diesel engines spanning 1994 to 2003 model years. Test vehicles were operated over city, suburban, and highway routes.

In 2007, US EPA implemented the rule that the crankcase emissions be added to the tailpipe emissions to determine the total emissions from a diesel engine if the crankcase were not closed, but few data exist to quantify crankcase emissions from earlier model diesel engines. This paper presents the results of a study on the measurement of the size distribution and number concentration of particulate matter (PM) emitted from the crankcase vents from four different diesel engines under different engine speeds and loads. The engines used in the study were a 1992 Detroit Diesel Series 60, a 1996 Caterpillar 3406E, a 1997 Cummins B5.9 and a 1995 Mack E7-400. The Detroit Diesel engine was tested on an engine dynamometer and crankcase and tailpipe particulates were observed at varying engine speeds and loads. The other three engines were mounted in vehicles, and crankcase PM was observed at several engine speeds with no external load.

Oxides of nitrogen (NOx) emissions, produced by engines that burn fuels with atmospheric air, are known to cause negative health and environmental effects. Increasingly stringent emissions regulations for marine engines have caused newer engines to be developed with inherent NOx reduction technologies. Older marine engines typically have a useful life of over 20 years and produce a disproportionate amount of NOx emissions when compared with their newer counterparts. Wet scrubbing as an aftertreatment method for emissions reduction was applied to ocean-going marine vessels for the reduction of sulfur oxides (SOx) and particulate matter (PM) emissions. The gaseous absorption process was explored in the laboratory as an option for reducing NOx emissions from older diesel engines of harbor craft operating in ports of Houston and Galveston. A scrubber system was designed, constructed, and evaluated to provide the basis for a real-world design.

The key to overcoming Low Temperature Combustion (LTC) load range limitations is based on suitable control over the thermo-chemical properties of the in-cylinder charge. The proposed alternative to achieve the required control of LTC is the use of two separate fuel streams to regulate timing and heat release at specific operational points, where the secondary fuel, with different autoignition characteristics, is a reformed product of the primary fuel in the tank. It is proposed in this paper that the secondary fuel is produced using Thermo-Chemical Recuperation (TCR) with steam/fuel reforming. The steam/fuel mixture is heated by sensible heat from the engine exhaust gases in the recuperative reformer, where the original hydrocarbon reacts with water to form a hydrogen rich gas mixture. An equilibrium model developed by Gas Technology Institute (GTI) for n-heptane steam reforming was applied to estimate reformed fuel composition at different reforming temperatures.

As emission regulations become increasingly strict, the need for more accurate sampling systems becomes essential. When calculating emissions from a dilution system, a correction is made to remove the effects of contaminants in the dilution air. The dilution air correction was explored to determine why this correction is needed, when this correction is important, and what methods are available for calculating the dilution factor (DF). An experimental and error analysis investigation into the standard and recently proposed methods for calculating the DF was conducted. Five steady state modes were run on a 1992 Detroit Diesel engine series 60 and the DF from eleven different equations were investigated. The effects of an inaccurate dilution air correction on calculated fuel flow from a carbon balance and the mass emissions was analyzed. The dilution air correction was shown to be important only for hydrocarbons, particulate matter (PM), and CO2.

Heavy-Duty Diesel (HDD) engines' particulate matter (PM) emissions are most often measured quantitatively by weighing filters that collect diluted exhaust samples pre- and post-test. PM sampling systems that dilute exhaust gas and collect PM samples have different effects on measured PM data. Those effects usually contribute to inter-laboratory variance. The U.S. Environmental Protection Agency (EPA)'s 2007 PM emission measurement regulations for the test of HDD engines should reduce variability, but must also cope with PM mass that is an order of magnitude lower than legacy engine testing. To support the design of a 2007 US standard HDD PM emission sampling system, a parametric study based on a systematic Simulink® model was performed. This model acted as an auxiliary design tool when setting up a new 2007 HDD PM emission sampling system in a heavy-duty test cell at West Virginia University (WVU). It was also designed to provide assistance in post-test data processing.

The U.S. Department of Energy (DOE) is embarking on a program investigating the use of Fischer-Tropsch (FT) fuels as a premium quality substitute or blending agent in direct-injection compression-ignition (diesel) engines. This paper aims to direct attention to the processing of FT fuels, emissions issues, available engine technology and the opportunity offered by FT diesel fuels for emissions control when considering diesel injection techniques. In modern automotive and heavy duty direct-injected (DI) diesel engines, precise fuel injection control is critical for achievement of 1998 and 2004 NOX and PM emission levels. High injection pressures, pilot injection and injection rate shaping are all optimized to maximize efficiency and power and to minimize emissions. These parameters must be considered as variables in the trade-off scenario between NOX and PM. Another parameter that may be considered important is the fuel type.

The temporary deactivation of the selective catalytic reduction (SCR) device due to malfunction requires the engine control to engage multiple engine-out calibrations. Further, it is expected that emitted particles will be different in composition, size and morphology when an engine, which meets the 2010 particulate matter (PM) gravimetric limits, is programmed with multiple maps. This study investigated the correlation between SCR-out/engine-out PM emissions from an 11-liter Volvo engine. Measurement of PM concentrations and size distributions were conducted under steady state and transient cycles. Ion Chromatograph analysis on gravimetric filters at the SCR-out has revealed the presence of sulfates. Two different PM size-distributions were generated over a single engine test mode in the accumulation mode region with the aid of a design of experiment (DOE) tool. The SCR-out PM size distributions were found to correlate with the two engine-out distributions.

For engine operations involving low load conditions for an extended amount of time, the exhaust temperature may be lower than that necessary to initiate the urea hydrolyzation. This would necessitate that the controller interrupt the urea supply to prevent catalyst fouling by products of ammonia decomposition. Therefore, it is necessary for the engine controller to have multiple calibrations available in regions of engine operation where the aftertreatment does not perform well, so that optimal exhaust conditions are guaranteed during the wide variety of engine operations. In this study the test engine was equipped with a catalyzed diesel particulate filter (DPF) and a selective catalytic reduction system (SCR), and programmed with two different engine calibrations, namely the low-NOx and the low fuel consumption (low-FC).

Dual primary full-flow dilution tunnels represent an integral part of a heavy-duty transportable emissions measurement laboratory designed and constructed to comply with US Code of Federal Regulations (CFR) 40 Part 1065 requirements. Few data exist to characterize the evolution of particulate matter (PM) in full scale dilution tunnels, particularly at very low PM mass levels. Size distributions of ultra-fine particles in diesel exhaust from a naturally aspirated, 2.4 liter, 40 kW ISUZU C240 diesel engine equipped with a diesel particulate filter (DPF) were studied in one set of standard primary and secondary dilution tunnels with varied dilution ratios. Particle size distribution data, during steady-state engine operation, were collected using a Cambustion DMS500 Fast Particulate Spectrometer. Measurements were made at four positions that spanned the tunnel cross section after the mixing orifice plate for the primary dilution tunnel and at the outlet of the secondary dilution tunnel.

Particulate emission control from diesel engines is one of the major concerns in the urban areas in California. Recently, regulations have been proposed for stringent PM emission requirements from both existing and new diesel engines. As a result, particulate emission control from urban diesel engines using advanced particulate filter technology is being evaluated at several locations in California. Although ceramic based particle filters are well known for high PM reductions, the lack of effective and durable regeneration system has limited their applications. The continuously regenerated diesel particulate filter (CRDPF) technology discussed in this presentation, solves this problem by catalytically oxidizing NO present in the diesel exhaust to NO2 which is utilized to continuously combust the engine soot under the typical diesel engine operating condition.

Exhaust emissions from off-highway diesel engines are a significant contributor of both oxides of nitrogen (NOx) and particulate matter (PM) to air inventories. Yet, emissions research activities aimed solely at the off-highway arena have been minimal - largely overshadowed by the extensive efforts directed toward the on-highway sector. However, with current trends indicating that the performance of these off-highway vehicles will become increasingly more scrutinized by federal regulatory agencies, augmentation of current research efforts will be necessary. The global objective for this study was to collect vehicle activity information for diesel-powered off-highway vehicles while they were operated in the field. Engine speed and raw exhaust CO2 concentrations were recorded and then used to create engine dynamometer test cycles. The engine was exercised according to these cycles in the laboratory so that the mass emissions rates of exhaust gas pollutants could be measured.

Further growth of diesel engines in the light-duty and heavy-duty vehicular market is closely linked to the potential health risks of diesel exhaust. The California Air Resources Board and the Office of Environmental Health Hazard Assessment have identified diesel exhaust as a toxic air contaminant. The International Agency for Research on Cancer concluded that diesel particulate is a probable human carcinogen [1]. Cleaner burning liquid fuels, such as those derived from natural gas via the Fischer-Tropsch (FT) process, offer a potentially economically viable alternative to standard diesel fuel while providing reduced particulate emissions. Further understanding of FT operation may be realized by investigating the differences in toxicity and potential health effects between particulate matter(PM) derived from FT fuel and that derived from standard Federal diesel No. 2 (DF).

The historical lack of continuous data for PM emissions from heavy-duty diesel engines hampers advanced inventory approaches and hampers second-by-second engine control optimization. Continuos PM data can be obtained using a Tapered Element Oscillating Microbalance (TEOM), but moisture correction of data is needed to remove unwanted transient components of the mass. Reasonable correlation can be found between TEOM data integrated over the cycle and conventional PM filter data. Considerable scatter was evident when continuous TEOM data were plotted against instantaneous power, but by dispersing the power in time a clearer relationship was evident. Continuous TEOM data showed the same gross trends as PM filter mass distributed over a cycle in proportion to instantaneous CO, but it was evident that this CO proportioning technique is at best approximate. Binning of PM mass rate as a function of vehicle speed and acceleration were also evaluated for inventory purposes.

Selective Catalytic Reduction (SCR), using urea injection, is being examined as a method for substantial reduction of oxides of nitrogen (NOx) for diesel engines, but the urea injection rates must be controlled to match the NOx production which may need to be predicted during open loop control. Unfortunately NOx is usually measured in the laboratory using a full-scale dilution tunnel and chemiluminescent analyzer, which cause delay and diffusion (in time) of the true manifold NOx concentration. Similarly, delay and diffusion of measurements of all emissions cause the task of creating instantaneous emissions models for vehicle simulations more difficult. Data were obtained to relate injections of carbon dioxide (CO2) into a tunnel with analyzer measurements. The analyzer response was found to match a gamma distribution of the input pulse, so that the analyzer output could be modeled from the tunnel CO2 input.

The emissions reduction of Fischer-Tropsch (FT) diesel fuel has been demonstrated in several recent publications in both laboratory engine testing and in-use vehicle testing. Reduced emission levels have been attributed to several chemical and physical characteristics of the FT fuels including reduced density, ultra-low sulfur levels, low aromatic content and high cetane rating. Some of the effects of these attributes on the combustion characteristics in diesel engines have only recently been documented. In this study, a Ricardo Proteous, single-cylinder, 4-stroke DI engine is instrumented for in-cylinder pressure measurements. The engine was run at several steady engine states at multiple timing conditions using both federal low sulfur and natural gas derived FT fuels. The emissions and performance data for each fuel at each steady state operating conditions were compared.

Emissions tests for heavy-duty diesel-fueled vehicles are normally performed using an engine dynamometer or a chassis dynamometer. Both of these methods generally entail the use of laboratory-grade emissions measurement instrumentation, a CVS system, an environment control system, a dynamometer, and associated data acquisition and control systems. The results obtained from such tests provide a means by which engines may be compared to the emissions standards, but may not be truly indicative of an engine's in-vehicle performance while operating on the road. An alternative to such a testing methodology would be to actively record the emissions from a vehicle while it was operating on-road. A considerable amount of discussion has been focused on the development of on-road emissions measurement systems (OREMS) that would provide for such in-use emissions data collection.

The use of Artificial Neural Networks (ANNs) as a predictive tool has been shown to have a broad range of applications. Earlier work by the authors using ANN models to predict carbon dioxide (CO2), carbon monoxide (CO), oxides of nitrogen (NOx), and particulate matter (PM) from heavy-duty diesel engines and vehicles yielded marginal to excellent results. These ANN models can be a useful tool in inventory prediction, hybrid vehicle design optimization, and incorporated into a feedback loop of an on-board, active fuel injection management system. In this research, the ANN models were trained on continuous engine and emissions data. The engine data were used as inputs to the ANN models and consisted of engine speed, torque, and their respective first and second derivatives over a one, five, and ten second time range. The continuous emissions data were the desired output that the ANN models learned to predict through an iterative training process.

Increased concerns about the emissions produced from mobile sources have placed an emphasis on the in-use monitoring of on- and off-road vehicles. Measuring the emissions emitted from an in-use vehicle during its operation provides for a rich dataset that is generally too expensive and too time consuming to reproduce in a laboratory setting. Many portable systems have been developed and implemented in the past to acquire in-use emissions data for spark ignited and compression ignited engines. However, the majority of these systems only measured the concentration levels of the exhaust constituents and or reported the results in time-specific (g/s) and or distance-specific (g/km) mass units through knowledge of the exhaust flow. For heavy-duty engines, it is desirable to report the in-use emission levels in brake-specific mass units (g/kW-hr) since that is how the emission levels are reported from engine dynamometer certification testing.