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Technical Paper

The Measurement of Exhaust Emissions from Oxygenated Fuel Blends by Fourier Transform Infrared Spectroscopy

Fourier Transform Infrared Spectroscopy (FT-IR) has been used to measure the exhaust emissions from vehicles during standard driving tests. Comparisons with conventional analyzers for modal tests have been made for the regulated species such as carbon monoxide (CO), nitrogen oxides (NOx) and total hydrocarbon (THC). The concentrations of methane, methanol and formaldehyde were also measured at one second time intervals during several driving tests. The average concentration values for these species were compared to the bag samples for several tests. Modal concentration curves were also calculated for MTBE, ETBE and several other species of interest. The results indicate FT-IR can be used for making modal measurements on the regulated species and non-regulated species in vehicle exhaust emissions. Several studies were performed to evaluate the long-term stability and sensitivity of FT-IR in actual test situations.
Technical Paper

Reformulated Gasoline Effects on Exhaust Emissions: Phase II: Continued Investigation of the Effects of Fuel Oxygenate Content, Oxygenate Type, Volatility, Sulfur, Olefins and Distillation Parameters

This study is the second in a series of three EPA studies to investigate the effect of fuel reformulations and modifications on exhaust emissions. Both the first and second study in this series of studies were used to support the development of EPA's complex model for the certification of reformulated gasolines. Phase I of the study tested eight fuels on forty vehicles. This study, termed Phase II, tested twelve fuels on a separate fleet of 39 light-duty vehicles. The Phase II fuel parameters studied included Reid Vapor Pressure (RVP), the 50% and 90% evaporated distillation temperatures (T50 and T90), sulfur content, aromatics content, olefin content, oxygenate type and oxygen content. Measured exhaust emissions included total hydrocarbons (THC), oxides of nitrogen (NOx), carbon monoxide (CO), carbon dioxide (CO2), benzene, 1,3-butadiene, acetaldehyde and formaldehyde.
Technical Paper

Reformulated Gasoline Effects on Exhaust Emissions: Phase I: Initial Investigation of Oxygenate, Volatility, Distillation and Sulfur Effects

This study was the first of three EPA studies to investigate the effect of gasoline fuel parameters on hydrocarbon, nonmethane hydrocarbon, nitrogen oxides, benzene, formaldehyde, and acetaldehyde exhaust emissions of 1990 model year or equivalent vehicles. The fuel parameters tested in this program were oxygen concentration, Reid Vapor Pressure (RVP), ninety percent evaporative distillation temperature (T90), and sulfur concentration. Sulfur concentration was found to have the greatest effect on hydrocarbon and nitrogen oxide emissions. Increasing oxygen concentration and RVP reduction was found to reduce hydrocarbon emission more for high-emitting than normal-emitting vehicles. Oxygenate concentration was found to have a significant effect on aldehyde emissions.
Technical Paper

Modeling and Validation of 12V Lead-Acid Battery for Stop-Start Technology

As part of the Midterm Evaluation of the 2017-2025 Light-duty Vehicle Greenhouse Gas Standards, the U.S. Environmental Protection Agency (EPA) developed simulation models for studying the effectiveness of stop-start technology for reducing CO2 emissions from light-duty vehicles. Stop-start technology is widespread in Europe due to high fuel prices and due to stringent EU CO2 emissions standards beginning in 2012. Stop-start has recently appeared as a standard equipment option on high-volume vehicles like the Chevrolet Malibu, Ford Fusion, Chrysler 200, Jeep Cherokee, and Ram 1500 truck. EPA has included stop-start technology in its assessment of CO2-reducing technologies available for compliance with the standards. Simulation and modeling of this technology requires a suitable model of the battery. The introduction of stop-start has stimulated development of 12-volt battery systems capable of providing the enhanced performance and cycle life durability that it requires.
Technical Paper

Testing of Catalytic Exhaust Emission Control Systems Under Simulated Locomotive Exhaust Conditions

Exhaust emissions were evaluated for four different catalytic exhaust emission control systems. Each system utilized a diesel oxidation catalyst, a metal-substrate partial-flow diesel particulate filter, an iron-exchanged or copper-exchanged Y-zeolite catalyst for urea selective catalytic reduction, and an ammonia slip catalyst. A 5.9-liter diesel truck engine was modified to match the exhaust conditions of a four-stroke diesel locomotive engine meeting the current Tier 2 locomotive emissions standards. NOx emissions, CO₂ emissions and exhaust temperatures were matched to the eight locomotive "throttle notch" power settings while exhaust mass flow was maintained near a constant fraction of locomotive exhaust mass flow for each "throttle notch" position. Regulated and unregulated exhaust emissions were measured over a steady-state test cycle for each of the four systems at low hours and following accelerated thermal aging and accelerated oil ash accumulation.
Technical Paper

Complex Systems Method Applied to Identify Carbon Dioxide Emission Reductions for Light-Duty Vehicles for the 2020-2025 Timeframe

The U.S. Environmental Protection Agency, U.S. Department of Transportation's National Highway and Traffic Safety Administration, and the California Air Resources Board have recently released proposed new regulations for greenhouse gas emissions and fuel economy for light-duty vehicles and trucks in model years 2017-2025. These proposed regulations intend to significantly reduce greenhouse gas emissions and increase fleet fuel economy from current levels. At the fleet level, these rules the proposed regulations represent a 50% reduction in greenhouse gas emissions by new vehicles in 2025 compared to current fleet levels. At the same time, global growth, especially in developing economies, should continue to drive demand for crude oil and may lead to further fuel price increases. Both of these trends will therefore require light duty vehicles (LDV) to significantly improve their greenhouse gas emissions over the next 5-15 years to meet regulatory requirements and customer demand.
Technical Paper

Evaluation of Gravimetric Method to Measure Light-Duty Vehicle Particulate Matter Emissions at Levels below One Milligram per Mile (1 mg/mile)

The California Air Resources Board (CARB) adopted the Low Emission Vehicle (LEV) III regulations in January 2012, which lowered the particulate matter (PM) emissions standards for light-duty vehicles (LDVs) from 10 milligrams per mile (10 mg/mile) to 3 mg/mile beginning with model year (MY) 2017 and 1 mg/mile beginning with MY 2025. To confirm the ability to measure PM emissions below 1 mg/mile, a total of 23 LDVs (MY pre-2004 to 2009) were tested at CARB's Haagen-Smit Laboratory (HSL) (10 LDVs) and the United States Environmental Protection Agency's (US EPA) National Vehicle and Fuel Emissions Laboratory (NVEFL) (13 LDVs) using the federal test procedure (FTP) drive schedule. One LDV with PM emissions ranging from 0.6 - 0.8 mg/mile was tested at three CARB HSL test cells to investigate intra-lab and inter-lab variability. Reference, trip, and tunnel filter blanks were collected as part of routine quality control (QC) procedures.
Technical Paper

Particulate Emissions in GDI Vehicle Transients: An Examination of FTP, HWFET, and US06 Measurements

With increasingly stringent light duty particulate emissions regulations, it is of great interest to better understand particulate matter formation. Helping to build the knowledge base for a thorough understanding of particulate matter formation will be an essential step in developing effective control strategies. It is especially important to do this in such a way as to emulate real driving behaviors, including cold starts and transients. To this end, this study examined particulate emissions during transient operation in a recent model year vehicle equipped with a GDI engine. Three of the major federal test cycles were selected as evaluation schemes: the FTP, the HWFET, and the US06. These cycles capture much of the driving behaviors likely to be observed in typical driving scenarios. Measurements included particle size distributions from a TSI EEPS fast-response particle spectrometer, as well as real-time soot emissions from an AVL MSS soot sensor.
Technical Paper

Fuel Effects Study with Small (<19kW) Spark-Ignited Off-Road Equipment Engines

This paper covers work performed for the California Air Resources Board and the United States Environmental Protection Agency by Southwest Research Institute. Emission measurements were made on nine types of off-road equipment with small (<19kW) spark-ignited engines including handheld and non-handheld equipment utilizing oxygenated and non-oxygenated fuels. Emission data was produced to augment ARB and EPA's off-road emission inventory. It was intended that this program provide ARB and EPA with emission test results they require for atmospheric modeling. The paper describes the equipment and engines tested, test procedures, emissions sampling methodologies, and emissions analytical techniques. Fuels used in the study are described, along with the emissions characterization results. The fuel effects on exhaust emissions and operation due to ethanol content and fuel components is compared.
Technical Paper

Fuel Effects Study with In-Use Two-Stroke Motorcycles and All-Terrain-Vehicles

This paper covers work performed for the California Air Resources Board and US Environmental Protection Agency by Southwest Research Institute. Emission measurements were made on four in-use off-road two-stroke motorcycles and all-terrain vehicles utilizing oxygenated and non-oxygenated fuels. Emission data was produced to augment ARB and EPA's off-road emission inventory. It was intended that this program provide ARB and EPA with emission test results they require for atmospheric modeling. The paper describes the equipment and engines tested, test procedures, emissions sampling methodologies, and emissions analytical techniques. Fuels used in the study are described, along with the emissions characterization results. The fuel effects on exhaust emissions and operation due to ethanol content and fuel components is compared.
Technical Paper

An HCCI Engine: Power Plant for a Hybrid Vehicle

Homogenous charge compression ignition (HCCI) engines offer a great potential in achieving high thermal efficiency and extremely low NOx at the same time. However, control of combustion phasing over a wide speed and load range has been a challenge, especially during transient operations. This paper describes work conducted at the National Vehicle and Fuel Emissions Laboratory, which explores the potential use of an HCCI engine as a power plant for a hybrid vehicle. A four-cylinder, 1.9 L commercial diesel engine was modified to operate with port-injected regular grade gasoline in HCCI mode. The combustion phasing is controlled by a combination of boost, EGR and thermal management as a function of engine speed and load. As a stand-alone unit, the engine has demonstrated a wide operation range with efficiency like that of a diesel engine and NOx below 0.2 g/kWh. At room temperature, the engine starts in SI mode and then transitions to HCCI in about 25 seconds.
Technical Paper

Central Carolina Vehicle Particulate Emissions Study

In-use, light-duty vehicles were recruited in Cary, North Carolina for emissions testing on a transportable dynamometer in 1999. Two hundred forty-eight vehicles were tested in as received condition using the IM240 driving cycle. The study was conducted in two phases, a summer and winter phase, with half of the vehicles recruited during each phase. Regulated emissions, PM10, carbonaceous PM, aldehydes and ketones were measured for every test. PM2.5, individual volatile hydrocarbons, polycyclic aromatic hydrocarbons, sterane and hopane emissions were measured from a subset of the vehicles. Average light-duty gasoline PM10 emission rates increased from 6.5 mg/mi for 1993-97 vehicles to 53.8 mg/mi for the pre-1985 vehicles. The recruited fleet average, hot-stabilized IM240 PM10 emission rate for gasoline vehicles was 19.0 mg/mi.
Technical Paper

Analysis of Technology Adoption Rates in New Vehicles

This paper examines the pace at which manufacturers have added certain powertrain technology into new vehicles from model year 1975 to the present. Based on data from the EPA's Light-Duty Automotive Technology, Carbon Dioxide Emissions, and Fuel Economy Trends database [1], the analysis will focus on several key technologies that have either reached a high level of penetration in light duty vehicles, or whose use in the new vehicle fleet has been growing in recent years. The findings indicate that individual manufacturers have, at times, implemented new technology across major portions of their new vehicle offerings in only a few model years. This is an important clarification to prior EPA analysis that indicated much longer adoption times for the industry as a whole. This new analysis suggests a technology penetration paradigm where individual manufacturers have a much shorter technology penetration cycle than the overall industry, due to “sequencing” by individual manufacturers.
Journal Article

Emissions of PCDD/Fs, PCBs, and PAHs from a Modern Diesel Engine Equipped with Selective Catalytic Reduction Filters

Exhaust emissions of seventeen 2,3,7,8-substituted chlorinated dibenzo-p-dioxin/furan (CDD/F) congeners, tetra-octa CDD/F homologues, twelve WHO 2005 chlorinated biphenyls (CB) congeners, mono-nona CB homologues, and nineteen polycyclic aromatic hydrocarbons (PAHs) from a model year 2008 Cummins ISB engine equipped with aftertreatment including a diesel oxidation catalyst (DOC) and wall flow copper or iron urea selective catalytic reduction filter (SCRF) were investigated. These systems differ from a traditional flow through urea selective catalytic reduction (SCR) catalyst because they place copper or iron catalyst sites in close proximity to filter-trapped particulate matter. These conditions could favor de novo synthesis of dioxins and furans. The results were compared to previously published results of modern diesel engines equipped with a DOC, catalyzed diesel particulate filter (CDPF) and flow through urea SCR catalyst.
Journal Article

A Pilot Study of Fuel Impacts on PM Emissions from Light-Duty Gasoline Vehicles

A pilot study was performed to explore the effects of PM Index, low and high molecular weight aromatics, and ethanol content on particulate matter (PM) emissions from light-duty Tier 2 gasoline vehicles. Four test vehicles from model years 2007-2009 were tested on seven fuels spanning PM Index values from 0.9 to 2.7, aromatic content from 14 to 38%, and ethanol content from 0 to 15%. Three of the test vehicles were port fuel injected (PFI) while the fourth featured gasoline direct injection (GDI). In an earlier program, two of the PFI vehicles demonstrated high sensitivity of PM emissions to fuel property changes while the third showed low sensitivity. The sensitivity of the GDI vehicle to fuel property changes was not known prior to this study. The vehicles were tested over the LA92 and US06 test cycles at 24°C (75°F). PM and regulated gaseous emissions were measured by test phase. Second-by-second tailpipe soot emissions were measured using the AVL Micro Soot Sensor.
Journal Article

A Comparison of Spray-Guided Stratified-Charge Combustion Performance with Outwardly-Opening Piezo and Multi-Hole Solenoid Injectors

This investigation was aimed at measuring the relative performance of two spray-guided, single-cylinder, spark-ignited direct-injected (SIDI) engine combustion system designs. The first utilizes an outwardly-opening poppet, piezo-actuated injector, and the second a conventional, solenoid operated, inwardly-opening multi-hole injector. The single-cylinder engine tests were limited to steady state, warmed-up conditions. The comparison showed that these two spray-guided combustion systems with two very different sprays had surprisingly close results and only differed in some details. Combustion stability and smoke emissions of the systems are comparable to each other over most of the load range. Over a simulated Federal Test Procedure (FTP) cycle, the multi-hole system had 15% lower hydrocarbon and 18% lower carbon monoxide emissions.
Journal Article

Determination of the PEMS Measurement Allowance for PM Emissions Regulated Under the Heavy-Duty Diesel Engine In-Use Testing Program

This paper summarizes the Heavy-Duty In-Use Testing (HDUIT) measurement allowance program for Particulate Matter Portable Emissions Measurement Systems (PM-PEMS). The measurement allowance program was designed to determine the incremental error between PM measurements using the laboratory constant volume sampler (CVS) filter method and in-use testing with a PEMS. Two independent PM-PEMS that included the Sensors Portable Particulate Measuring Device (PPMD) and the Horiba Transient Particulate Matter (TRPM) were used in this program. An additional instrument that included the AVL Micro Soot Sensor (MSS) was used in conjunction with the Sensors PPMD to be considered a PM-PEMS. A series of steady state and transient tests were performed in a 40 CFR Part 1065 compliant engine dynamometer test cell using a 2007 on-highway heavy-duty diesel engine to quantify the accuracy and precision of the PEMS in comparison with the CVS filter-based method.
Journal Article

HCCI Engine Application on a Hydraulic Hybrid Bus

After initial trials on Homogeneous Charge Compression Ignition (HCCI) engine design and tests pursuing feedback control to avoid misfire and knocking over wide transient operation ranges, Engineers at the US Environmental Protection Agency's (EPA) National Vehicle Fuel and Emissions Laboratory identified the crucial engine state variable, MRPR (Maximum Rate of Pressure Rise) and successfully controlled a 1.9L HCCI engine in pure HCCI mode [1]. This engine was used to power a hybrid Ford F-150 truck which successfully ran FTP75 tests in 2004. In subsequent research, efforts have been focused on practical issues such as improving transient rate, system simplification for controllability and packaging, application of production grade in-cylinder pressure sensors, cold start, idling and calibration for ambient conditions as well as oxidation catalyst applications for better turbine efficiency and HC and CO emissions control.
Journal Article

In-Use Emissions from Non-road Equipment for EPA Emissions Inventory Modeling (MOVES)

Because of U.S. EPA regulatory actions and the National Academies National Research Council suggestions for improvements in the U.S. EPA emissions inventory methods, the U.S. EPA' Office of Transportation and Air Quality (OTAQ) has made a concerted effort to develop instrumentation that can measure criteria pollutant emissions during the operation of on-road and off-road vehicles. These instruments are now being used in applications ranging from snowmobiles to on-road passenger cars to trans-Pacific container ships. For the betterment of emissions inventory estimation these on-vehicle instruments have recently been employed to measure time resolved (1 hz) in-use gaseous emissions (CO₂, CO, THC, NO ) and particulate matter mass (with teflon membrane filter) emissions from 29 non-road construction vehicles (model years ranging from 1993 to 2007) over a three year period in various counties in Iowa, Missouri, and Kansas.
Technical Paper

Real-World Emission Modeling and Validations Using PEMS and GPS Vehicle Data

Portable Emission Measurement Systems (PEMS) are used by the U.S. Environmental Protection Agency (EPA) to measure gaseous and particulate mass emissions from vehicles in normal, in-use, on-the-road operation to support many of its programs, including assessing mobile source emissions compliance, emissions factor assessment for in-use fleet modeling, and collection of in-use vehicle operational data to support vehicle simulation modeling programs. This paper discusses EPA’s use of Global Positioning System (GPS) measured altitude data and electronically logged vehicle speed data to provide real-world road grade data for use as an input into the Gamma Technologies GT-DRIVE+ vehicle model. The GPS measured altitudes and the CAN vehicle speed data were filtered and smoothed to calculate the road grades by using open-source Python code and associated packages.