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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.

A 28-vehicle fleet test was executed to verify and quantify the NOX emissions reductions achieved through the use of Infineum's Vektron 6913 gasoline additive. The fleet composition and experimental design were finalized in collaborative discussions with US Environmental Protection Agency (EPA) Office of Transportation & Air Quality (OTAQ) and consultation / advice from several major US automotive manufacturers. The test was conducted over a period of five months at Southwest Research Institute. Statistical analysis of the emissions data indicated a 10% average fleet reduction in NOX emissions without any negative impact on other criteria pollutants (CO, HC) or fuel economy.

Vegetable oils are candidates for alternative fuels in diesel engines. These oils, such as soybean, sunflower, rapeseed, cottonseed, and peanut, consist of various triglycerides. The chemistry of the degradation of vegetable oils when used as alternate diesel fuels thus corresponds to that of triglycerides. To study the chemistry occurring during the precombustion phase of a vegetable oil injected into a diesel engine, a reactor simulating a diesel engine was constructed. Pure triglycerides were injected into the reactor in order to determine differences in the precombustion behavior of the various triglycerides. The reactor allowed motion pictures to be prepared of the injection event as the important reaction parameters, such as pressure, temperature, and atmosphere were varied. Furthermore, samples of the degradation products of precombusted triglycerides were collected and analyzed (gas chromatography / mass spectrometry).

A program to demonstrate the performance of advanced emission control systems in light of the California LEV II light-duty vehicle standards and the EPA's consideration of Tier II emission standards was conducted. Two passenger cars and one light-duty pick-up truck were selected for testing, modification, and emission system performance tuning. All vehicles were 1997 Federal Tier I compliant. The advanced emission control technologies evaluated in this program included advanced three-way catalysts, high cell density substrates, and advanced thermally insulated exhaust components. Using these engine-aged advanced emission control technologies and modified stock engine control strategies (control modifications were made using an ERIC computer intercept/control system), each of the three test vehicles demonstrated FTP emission levels below the proposed California LEV II 193,000 km (120,000 mile) ULEV levels.

As GHG and fuel economy regulations of light-duty vehicles have become more stringent, advanced emissions reduction technology has extensively penetrated the US light-duty vehicle fleet. This new technology includes not only advanced conventional engines and transmissions, but also greater adoption of electrified powertrains. In 2022, electrified vehicles – including mild hybrids, strong hybrids, plug-ins, and battery electric vehicles – made up nearly 17% of the US fleet and are on track to further increase their proportion in subsequent years. The Environmental Protection Agency (EPA) has previously used its Advanced Light-Duty Powertrain and Hybrid Analysis (ALPHA) full vehicle simulation tool to evaluate the greenhouse gas (GHG) emissions of light-duty vehicles. ALPHA contains a library of benchmarked powertrain components that can be matched to specific vehicles to explore GHG emissions performance.

The use of alcohol as a supplemental fuel for a medium-speed diesel engine was investigated using a two-cylinder, two-stroke test engine. Both stabilized and unstabilized emulsions of methanol-in-diesel fuel and ethanol-in-diesel fuel were tested. Also, anhydrous ethanol/diesel fuel solutions were evaluated. Maximum alcohol content of the emulsions and solutions was limited by engine knocking due to a reduction in fuel cetane number. Engine power and thermal efficiency were slightly below baseline diesel fuel levels in the high and mid-speed ranges, but were somewhat improved at low speeds during tests of the unstabilized emulsions and the ethanol solutions. However, thermal efficiency of the stabilized emulsions fell below baseline levels at virtually all conditions.

Regulated and unregulated exhaust emissions (individual hydrocarbons, aldehydes and ketones, polynuclear aromatic hydrocarbons (PAH), and nitro-polynuclear aromatic hydrocarbons (NPAH)) were characterized for the following alternate diesel combustion modes: premixed charge compression ignition (PCCI), and low-temperature combustion (LTC). PCCI and LTC were studied on a PSA light-duty high-speed diesel engine. Engine-out emissions of carbonyl compounds were significantly increased for all LTC modes and for PCCI-Lean conditions as compared to diesel operation; however, PCCI-Rich produced much lower carbonyl emissions than diesel operations. For PAH compounds, emissions were found to be substantially increased over baseline diesel operation for LTC-Lean, LTC-Rich, and PCCI-Lean conditions. PCCI-Rich operation, however, gave PAH emission rates comparable to baseline diesel operation.

Beginning June 1, 2006, 80% of the highway diesel fuel produced in the United States had to contain 15 ppm sulfur or less. To account for sulfur test method variability, the United States Environmental Protection Agency (US EPA) allowed a 2 ppm compliance margin, meaning that in an EPA enforcement action fuel measuring 17 ppm or less would still be deemed compliant since the true sulfur level could still be 15 ppm. Concern was voiced over the appropriateness of the 2 ppm compliance margin, citing recent American Society for Testing and Materials (ASTM) round-robin and crosscheck test program results that showed sulfur test lab-to-lab variability (reproducibility) on the order of 4 to 5 ppm depending on test method.

The goal of this project was to demonstrate a low emissions, high efficiency heavy-duty on-highway natural gas engine. The emissions targets for this project are to demonstrate US 2010 emissions standards on the 13-mode steady state test. To meet this goal, a chemically correct combustion (stoichiometric) natural gas engine with exhaust gas recirculation (EGR) and a three way catalyst (TWC) was developed. In addition, a Sturman Industries, Inc. camless Hydraulic Valve Actuation (HVA) system was used to improve efficiency. A Volvo 11 liter diesel engine was converted to operate as a stoichiometric natural gas engine. Operating a natural gas engine with stoichiometric combustion allows for the effective use of a TWC, which can simultaneously oxidize hydrocarbons and carbon monoxide and reduce NOx. High conversion efficiencies are possible through proper control of air-fuel ratio.

Comparative emission measurements were made in two dynamometer-based diesel engines using protocol specified by the U.S. Environmental Protection Agency (EPA) and the California Air Resources Board (CARB). A single JP-8 fuel with a sulfur level of 0.06 weight percent (wt%) was adjusted to sulfur levels of 0.11 and 0.26 wt%. The emission characteristics of the three fuels were compared to the 1994 EPA certification low-sulfur diesel fuel (sulfur level equal to 0.035 wt%) in the Detroit Diesel Corporation (DDC) 1991 prototype Series 60 diesel engine and in the General Motors (GM) 6.2L diesel engine. Comparisons were made using the hot-start transient portion of the heavy-duty diesel engine Federal Test Procedure. Results from the Army study show that the gaseous emissions for the DDC Series 60 engine using kerosene-based JP-8 fuel are equivalent to values obtained with the 0.035 wt% sulfur EPA certification diesel fuel.

Due to its high efficiency and superior durability the diesel engine is again becoming a prime candidate for future light-duty vehicle applications within the United States. While in Europe the overall diesel share exceeds 40%, the current diesel share in the U.S. is 1%. Despite the current situation and the very stringent Tier 2 emission standards, efforts are being made to introduce the diesel engine back into the U.S. market. In order to succeed, these vehicles have to comply with emissions standards over a 120,000 miles distance while maintaining their excellent fuel economy. The availability of technologies such as high-pressure common-rail fuel systems, low sulfur diesel fuel, NOx adsorber catalysts (NAC), and diesel particle filters (DPFs) allow the development of powertrain systems that have the potential to comply with the light-duty Tier 2 emission requirements. In support of this, the U.S.

Radioactive tracer technology (RATT™) is an important tool for measuring real-time wear in operating engines and other mechanical systems. The use of this technology provides important wear information that is not available by other, more conventional wear measurement methods. The technology has advanced to the point where several components can be interrogated simultaneously, and new methods have extended the method to materials that are normally not amenable to radioactive tracer evaluation. In addition, sensitivity has increased so that the onset of wear can be detected long before practical with non-tracer methods. This improves the ability to measure and determine cause and effect relationships, thus providing a better understanding of wear responses to specific operating conditions and to changes in operating conditions. This paper reviews the radioactive tracer process and recent improvements that have extended its reach in both automotive and non-automotive applications.

The objective was to demonstrate the feasibility of operating a natural gas two-stroke engine using glow plug ignition with very lean mixtures. Based on the results obtained, the term SCGI (stratified charge glow plug ignition) was coined to describe the engine. An JLO two-stroke diesel engine was converted first to a natural gas fueled spark-ignited engine for the baseline tests, and then to an SCGI engine. The SCGI engine used a gas operated valve in the cylinder head to admit the natural gas fuel, and a glow plug was used as a means to initiate the combustion. The engine was successfully run, but was found to be sensitive to various conditions such as the glow plug temperature. The engine would run very lean, to an overall equivalence ratio of 0.33, offering the potential of good fuel economy and low NOx emissions.

In response to increasing concern about snowmobile noise and air pollution, Teton County Wyoming Commissioner Bill Paddleford and environmental engineer Dr. Lori Fussell worked with The Society of Automotive Engineers (SAE) and the Institute of Science, Ecology, and the Environment (ISEE) to organize an intercollegiate design competition, the SAE Clean Snowmobile Challenge (SAE CSC). The goal of the SAE CSC was to encourage development of a snowmobile with improved emission and noise characteristics that does not sacrifice performance. Modifications were expected to be cost effective and practical. The second year of the competition, the SAE CSC2001, was held in Jackson Hole, Wyoming from March 24 - 30, 2001.

A dilute spark-ignited engine concept has been developed as a potential low cost competitor to diesel engines by Southwest Research Institute (SwRI), with a goal of diesel-like efficiency and torque for light- and medium-duty applications and low-cost aftertreatment. The targeted aftertreatment method is a traditional three-way catalyst, which offers both an efficiency and cost advantage over typical diesel aftertreatment systems. High levels of exhaust gas recirculation (EGR) have been realized using advanced ignition systems and improved combustion, with significant improvements in emissions, efficiency, and torque resulting from using high levels of EGR. The primary motivation for this work was to understand the impact high levels of EGR would have on particulate matter (PM) formation in a port fuel injected (PFI) engine. While there are no proposed regulations for PFI engine PM levels, the potential exists for future regulations, both on a size and mass basis.

SwRI has developed a new technology concept involving the use of high EGR rates coupled with a high-energy ignition system in a gasoline engine to improve fuel economy and emissions. Based on a single-cylinder study [1], this study extends the concept of a high compression ratio gasoline engine with EGR rates > 30% and a high-energy ignition system to a multi-cylinder engine. A 2000 MY Isuzu Duramax 6.6 L 8-cylinder engine was converted to run on gasoline with a diesel pilot ignition system. The engine was run at two compression ratios, 17.5:1 and 12.5:1 and with two different EGR systems - a low-pressure loop and a high pressure loop. A high cetane number (CN) diesel fuel (CN=76) was used as the ignition source and two different octane number (ON) gasolines were investigated - a pump grade 91 ON ((R+M)/2) and a 103 ON ((R+M)/2) racing fuel.

Extensive efforts are being made to improve emissions from 2-stroke diesel engines. These improvements are primarily directed towards older model year engines with relatively high emissions compared with modern diesel engines. While most researchers focus their attention on engine design changes that promise substantial emission improvements, this work dealt with the turbocharger characteristics, especially as related to using internal coatings on both the compressor and turbine housings. Two identical turbochargers were tested on a Detroit Diesel 6V-92TA engine. One of the two turbochargers was left in its production configuration while the other was coated with a clearance control coating on the inside of the compressor and turbine housings. This coating led to a significant reduction in the tip clearance of both the compressor and turbine wheels.

A combined, experimental and numerical program is presented. This work summarizes an internal research effort conducted at Southwest Research Institute. Meeting new, stringent emissions regulations for diesel engines requires a way to reduce NOx and soot emissions. Most emissions reduction strategies reduce one pollutant while increasing the other. Water injection is one of the few promising emissions reduction techniques with the potential to simultaneously reduce soot and NOx in diesel engines. While it is widely accepted that water reduces NOx via a thermal effect, the mechanisms behind the reduction of soot are not well understood. The water could reduce the soot via physical, thermal, or chemical effects. To aid in developing water injection strategies, this project's goal was to determine how water enters the soot formation chemistry.

Diesel Cylinder Deactivation (CDA) has been shown in previous work to increase exhaust temperatures, improve fuel efficiency, and reduce engine-out NOx for engine loads up to 3 bar BMEP. The purpose of this study is to determine whether or not the turbocharger needs to be altered when implementing CDA on a diesel engine. This study investigates the effect of CDA on exhaust temperature, fuel efficiency, and turbocharger performance in a 15L heavy-duty diesel engine under low-load (0-3 bar BMEP) steady-state operating conditions. Two calibration strategies were evaluated. First, a “stay-hot” thermal management strategy in which CDA was used to increase exhaust temperature and reduce fuel consumption. Next, a “get-hot” strategy where CDA and elevated idle speed was used to increase exhaust temperature and exhaust enthalpy for rapid aftertreatment warm-up.

Work was performed to determine the feasibility of operating heavy-duty natural gas engines over a wide range of fuel compositions by evaluating engine performance and emission levels. Heavy-duty compressed natural gas engines from various engine manufacturers, spanning a range of model years and technologies, were evaluated using a diversity of fuel blends. Performance and regulated emission levels from these engines were evaluated using natural gas fuel blends with varying methane number (MN) and Wobbe Index in a dynamometer test cell. Eight natural gas blends were tested with each engine, and ranged from MN 75 to MN 100. Test engines included a 2007 model year Cummins ISL G, a 2006 model year Cummins C Gas Plus, a 2005 model year John Deere 6081H, a 1998 model year Cummins C Gas, and a 1999 model year Detroit Diesel Series 50G TK. All engines used lean-burn technology, except for the ISL G, which was a stoichiometric engine.