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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.

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.

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.

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.

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.

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.

Port-fuel-injection (PFI) problems were first reported late in 1984. Deposits that formed on the tip of the pintle-type injectors of certain engines restricted fuel flow and caused driveability and emission problems. Responding to this problem, industry test programs were initiated to reproduce the deposits under controlled conditions. In 1986, a vehicle test procedure was identified and the automotive industry recommended a pass/fail performance level. Building upon available information, the Coordinating Research Council's (CRC) Port Fuel Injector Deposit Group developed a standard vehicle test procedure to evaluate various unleaded gasolines for port-fuel-injection fouling. The vehicle test procedure was adopted as an ASTM test method. The United States Environmental Protection Agency (EPA) and the State of California accepted the procedure as the standard for measuring a gasoline's propensity to form deposits in a pintle-type injector.

Commercial vehicles require fast aftertreatment heat-up to move the SCR catalyst into the most efficient temperature range to meet upcoming NOX regulations while minimizing CO2. The focus of this paper is to identify the technology levers when used independently and also together for the purpose of NOX and CO2 reduction toward achieving 2027 emissions levels while remaining CO2 neutral or better. A series of independent levers including cylinder deactivation, LO-SCR, electric aftertreatment heating and fuel burner technologies were explored. All fell short for meeting the 2027 CARB transient emission targets when used independently. However, the combinations of two of these levers were shown to approach the goal of transient emissions with one configuration meeting the requirement. Finally, the combination of three independent levers were shown to achieve 40% margin for meeting 2027 transient NOx emissions while remaining CO2 neutral.

TFC/IW, total fuel consumption divided by inertia (test) weight is a useful concept in analyzing the total or composite fuel economy generated in thousands of tests using the carbon balance technique in EPA Federal Test Procedure and Highway Driving Cycle. TFC/IW is a measure of drive train efficiency that requires no additional complicating assumptions. It is applicable to one test or a fleet representing many tests.

Spark discharge properties were studied and characterized for varying gas compositions and spark plug geometries using a spark calorimeter and constant volume optical vessel. Two different 18 mm natural gas engine spark plugs were used in the experiments. All measurements were recorded under quiescent conditions and with a spark gap of 0.30 mm. The spark plug calorimeter was used for measuring thermal energy deposition to the gas for gas compositions of nitrogen, a stoichiometric mixture of nitrogen and methane, a stoichiometric mixture of nitrogen and methane diluted with 30% carbon dioxide by volume, and for air. Other measurements of interest included breakdown voltage, electrical energy delivered to the spark gap, electrical-to-thermal energy conversion efficiency, and spark duration, for pressures up to 28 bar at 300 K. The optical vessel was used for the combusting mixture of stoichiometric air and methane at pressures up to 28 bar.

Five light-duty vehicles were used to investigate HC, CO, and NOx emissions and fuel economy sensitivity to changes in the length of soak period preceding the EPA Urban Dynamometer Driving Schedule (UDDS). Emission tests were conducted following soak periods 10 minutes to 36 hours in length. Each of the first 8 minutes of the driving cycle was studied separately to observe vehicle warm-up. Several engine and fuel system temperatures were monitored during soak and run periods and example trends are illustrated. The extent to which emission rates and fuel consumption are affected by soak period length is discussed.

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.

This paper describes experiments conducted to determine Federal Test Procedure (FTP) exhaust emissions, ozone-forming potentials, specific reactivities, and reactivity adjustment factors for several butane/propane alternative fuel blends run on a light-duty EHC-equipped gasoline vehicle converted to operate on liquefied petroleum gas (LPG). Duplicate emission tests were conducted on the light-duty vehicle at each test condition using appropriate EPA FTP test protocol. Hydrocarbon speciation was utilized to determine reactivity-adjusted non-methane organic gas (NMOG) emissions for one test on each fuel.

This paper describes experiments conducted to determine the ozone-forming potentials, specific reactivities, and reactivity adjustment factors for various heavy-duty engines operating on “industry average” (RF-A) gasoline, California Phase 2 gasoline, compressed natural gas (CNG), liquefied petroleum gas (LPG), and diesel fuel. Each engine/fuel combination was tested in triplicate using the EPA heavy-duty transient cold- and hot-start test protocol. Hydrocarbon speciation was conducted for all tests to allow for the determination of ozone-forming potentials, using California Air Resources Board maximum incremental reactivity factors as well as determination of the Clean Air Act “toxic” emissions.

Road tests of class 8 tractor trailers were conducted by the US Environmental Protection Agency (EPA) on a new and retreaded tires of varying rolling resistance in order to provide estimates of the quantitative relation between rolling resistance and fuel consumption. Reductions in fuel consumption were measured using the SAE J1231 (reaffirmation of 1986) test method. Vehicle rolling resistance was calculated as a load-weighted average of the rolling resistance (as measured by ISO28580) of the tires in each axle position. Both new and retreaded tires were tested in different combinations to obtain a range of vehicle coefficient of rolling resistance from a baseline of 7.7 kg/ton to 5.3 kg/ton. Reductions in fuel consumption displayed a strong linear relationship with coefficient of rolling resistance, with a maximum reduction of fuel consumption of 10 percent relative to the baseline.

This paper describes the results of a public opinion survey on testing of diesel exhaust odors conducted during 1969 and 1970. Major goals of the research were to relate public opinion of the odors and the objectionability associated with them to odor intensity, and to obtain a dose-response curve as the primary result. The dose-response curve was needed to assess odor-control technology by providing a criterion for deciding whether or not the effect of a given control item would be noticed by the general public, reduce complaints, or be worth the cost and effort required for its implementation. The engine used as the live odor source for the subject research was a two-stroke cycle type similar to those used in many buses. This engine type was chosen because its exposure to the public in urban bus applications is very widespread, and because a large portion of the Environmental Protection Agency's odor research had been performed with similar engines.

The thermal efficiency benefits of low-pressure (LP) exhaust gas recirculation (EGR) in spark-ignition engine combustion are well known. One of the greatest barriers facing adoption of LP-EGR for high power-density applications is the challenge of boosting. Variable nozzle turbines (VNTs) have recently been developed for gasoline applications operating at high exhaust gas temperatures (EGTs). The use of a single VNT as a boost device may provide a lower-cost option compared to two-stage boosting systems or 48 V electronic boost devices for some LP-EGR applications. A predictive model was created based on engine testing results from a 1.6 L turbocharged gasoline direct injection (GDI) engine [1]. The model was tuned so that it predicted burn-rates and end-gas knock over an engine operating map with varying speeds, loads, EGR rates and fuel types.

In 2005, the United States Environmental Protection Agency (EPA) and Southwest Research Institute (SwRI) embarked on a mission to help the city of Beijing, China, clean its air. Working with the Beijing Environmental Protection Bureau (BEPB), the effort was a pilot diesel retrofit demonstration program involving three basic retrofit technologies to reduce particulate matter (PM). The three basic technologies were the diesel oxidation catalyst (DOC), the flowthrough diesel particulate filter (FT-DPF), and the wallflow diesel particulate filter (WF-DPF). The specific retrofit systems selected for the project were verified through the California Air Resources Board (CARB) or the EPA verification protocol [1]. These technologies are generally verified for PM reductions of 20-40 percent for DOCs, 40-50 percent for the FT-DPF, and 85 percent or more for the high efficiency WF-DPF.

The use of a partial flow sampling system (PFSS) to measure nonroad steady-state diesel engine particulate matter (PM) emissions is a technique for certification approved by a number of regulatory agencies around the world including the US EPA. Recently, there have been proposals to change future nonroad tests to include testing over a nonroad transient cycle. PFSS units that can quantify PM over the transient cycle have also been discussed. The full flow constant volume sampling (CVS) technique has been the standard method for collecting PM under transient engine operation. It is expensive and requires large facilities as compared to a typical PFSS. Despite the need for a cheaper alternative to the CVS, there has been a concern regarding how well the PM measured using a PFSS compared to that measured by the CVS. In this study, three PFSS units, including AVL SPC, Horiba MDLT, and Sierra BG-2 were investigated in parallel with a full flow CVS.