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Technical Paper

Relationship among Various Particle Characterization Metrics Using GDI Engine Based Light-Duty Vehicles

2018-04-03
2018-01-0353
In recent years, gasoline direct injection (GDI) engines have been widely used by manufacturers in light-duty to meet stringent fuel economy and emissions standards. This study focuses on the relationship between various particle metrics such as number, size, surface area and mass of dilute exhaust particles from 12 different light-duty vehicles equipped with GDI engines. The campaign included the measurement of total particulate matter (PM) using Title 40 CFR Part 1066 compliant filter measurement, soot mass using photo-acoustics based analyzer, organic carbon (OC) & elemental carbon (EC) mass using thermo-optical analysis of quartz filter samples, solid particle number using European Union Regulation No. 49 compliant number system and solid particle size/number using an electrical mobility based size spectrometer.
Technical Paper

Solid Particle Number and Ash Emissions from Heavy-Duty Natural Gas and Diesel w/SCRF Engines

2018-04-03
2018-01-0362
Solid and metallic ash particle number (PN) and particulate matter (PM) mass emission measurements were performed on a heavy-duty (HD) on-highway diesel engine and a compressed natural gas (CNG) engine. Measurements were conducted under transient engine operation that included the FTP, WHTC and RMC. Both engines were calibrated to meet CARB ultra low NOX emission target of 0.02 g/hp-hr, a 90% reduction from current emissions limit. The HD diesel engine final exhaust configuration included a number of aftertreatement sub-systems in addition to a selective catalytic reduction filter (SCRF). The stoichiometric CNG engine final configuration included a closed coupled Three Way Catalyst (ccTWC) and an under floor TWC (ufTWC). The aftertreatment systems for both engines were aged for a full useful life (FUL) of 435,000 miles, prior to emissions testing. PM mass emissions from both engines were comparable and well below the US EPA emissions standard.
Journal Article

Solid Particle Emissions from Vehicle Exhaust during Engine Start-Up

2015-04-14
2015-01-1077
Human exposure to vehicle exhaust during engine start-up can be encountered on a daily basis in parking lots, home garages, and vehicle stop/star traffic environment. This work is the first pilot study to characterize solid particle number and size distribution during engine start-up using various light-duty vehicles with different technology engines. A total of 84 vehicles were tested in this pilot study, consisting of post-2007 diesel engines equipped with high efficiency diesel particulate filters (DPFs) as well as modern gasoline port fuel injected (PFI) and gasoline direct injected (GDI) engines equipped with three-way-catalysts (TWCs). Particle concentration from DPF equipped diesel engines were found to be the lowest, while GDI and 8-cylinder PFI engines had the highest particle emissions.
Journal Article

Measurement of In-use PM using Soot Augmented with a Gravimetric Reference

2012-04-16
2012-01-1254
Diesel PM is understood to comprise elemental carbonaceous particles, an organic fraction of soluble or volatile hydrocarbons and sometimes a sulfate fraction. The need to measure such diesel PM at very low levels and to measure it outside of the usual engine test laboratory makes it helpful to sharpen our understanding of this detail composition and how it comes about. Real time instruments for measuring soot and particle number concentrations make it possible to discern emissions levels much lower than filter based laboratory measurements, but an understanding of the relationships between these measurements and the historical reference methods makes them more useful for development and certification of engines. Efforts to use soot measurements in-use in order to meet NTE requirements have shown good correlation to the laboratory reference and have also provided some new information on the shortcomings of the reference methods.
Journal Article

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

2012-04-16
2012-01-1250
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

Effect of EGR on Particle Emissions from a GDI Engine

2011-04-12
2011-01-0636
Gasoline direct injected (GDI) engines are becoming a concern with respect to particulate matter (PM) emissions. The upcoming 2014 Euro 6 regulations may require a drastic reduction in solid particle number emissions from GDI engines and the proposed California Air Resources Board (CARB) LEV III regulations for 2014 and 2017 will also require some PM reduction measures. As a result, it is necessary to characterize PM emissions from GDI engines and investigate strategies that suppress particle formation during combustion. The main focus of this work was on using exhaust gas recirculation (EGR) as a means to reduce engine-out particle emissions from a GDI engine with an overall stoichiometric fuel to air mixture. A small displacement, turbocharged GDI engine was operated at a variety of steady-state conditions with differing levels of EGR to characterize total (solid plus volatile) and solid particle emissions with respect to size, number, and soot or black carbon mass.
Journal Article

Development of a Solid Exhaust Particle Number Measurement System Using a Catalytic Stripper Technology

2011-04-12
2011-01-0635
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.
Journal Article

Particle Emissions from a 2009 Gasoline Direct Injection Engine Using Different Commercially Available Fuels

2010-10-25
2010-01-2117
Total and solid particle mass, size, and number were measured in the dilute exhaust of a 2009 vehicle equipped with a gasoline direct injection engine along with an exhaust three-way-catalyst. The measurements were performed over the FTP-75 and the US06 drive cycles using three different U.S. commercially available fuels, Fuels A, B, and C, where Fuel B was the most volatile and Fuel C was the least volatile with higher fractions of low vapor pressure hydrocarbons (C10 to C12), compared to the other two fuels. Substantial differences in particle mass and number emission levels were observed among the different fuels tested. The more volatile gasoline fuel, Fuel B, resulted in the lowest total (solid plus volatile) and solid particle mass and number emissions. This fuel resulted in a 62 percent reduction in solid particle number and an 88 percent reduction in soot mass during the highest emitting cold-start phase, Phasel, of the FTP-75, compared to Fuel C.
Journal Article

The Role of EGR in PM Emissions from Gasoline Engines

2010-04-12
2010-01-0353
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.
Technical Paper

Verification of a Gaseous Portable Emissions Measurement System with a Laboratory System Using the Code of Federal Regulations Part 1065

2010-04-12
2010-01-1069
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.
Journal Article

1000-Hour Durability Evaluation of a Prototype 2007 Diesel Engine with Aftertreatment Using B20 Biodiesel Fuel

2009-11-02
2009-01-2803
A prototype 2007 ISL Cummins diesel engine equipped with a diesel oxidation catalyst (DOC), diesel particle filter (DPF), variable geometry turbocharger (VGT), and cooled exhaust gas recirculation (EGR) was tested at Southwest Research Institute (SwRI) under a high-load accelerated durability cycle for 1000 hours with B20 soy-based biodiesel blends and ultra-low sulfur diesel (ULSD) fuel to determine the impact of B20 on engine durability, performance, emissions, and fuel consumption. At the completion of the 1000-hour test, a thorough engine teardown evaluation of the overhead, power transfer, cylinder, cooling, lube, air handling, gaskets, aftertreatment, and fuel system parts was performed. The engine operated successfully with no biodiesel-related failures. Results indicate that engine performance was essentially the same when tested at 125 and 1000 hours of accumulated durability operation.
Technical Paper

Portable Emissions Measurement for Retrofit Applications – The Beijing Bus Retrofit Experience

2008-06-23
2008-01-1825
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.
Technical Paper

Diesel Exhaust Particulate Sampler for On-board PM Measurement

2008-04-14
2008-01-1180
Horiba on-board diesel exhaust particulate sampler (OBS-PM) is a filter based partial flow particulate sampling system used for On-board diesel particulate matter (PM) measurement. It takes sample from either raw or diluted exhaust. It can run at constant dilution ratios or at variable dilution ratios with proportional control on the sample flow. The diluted exhaust moves through a pre-weighed 47 mm particulate filter and PM is collected on the filter. By weighing the loaded sample filter, PM emission from the engine or the vehicle can be determined. The performance of the OBS-PM meets most of requirements for a real-time partial flow sample system (PFSS) recommended by ISO 16183 [2]. The physical size and the power consumption of the instrument are minimized. It is powered with four 12 volts batteries, and can be installed on a vehicle for real-world PM emission evaluation.
Technical Paper

Sampling System for Solid and Volatile Exhaust Particle Size, Number, and Mass Emissions

2007-04-16
2007-01-0307
A solid particle sampling system (SPSS) that is equipped with a heated oxidation catalyst, micro-dilution tunnels, filter holders and sampling probes, was designed and developed to collect filter-based solid and total (solid plus volatile) particles from the exhaust of internal combustion engines, and to facilitate the measurement of solid and total particles when equipped with particle measuring instruments for size, number, mass, and other particle characteristics. The SPSS was characterized with laboratory aerosol and showed a very low solid particle loss of less than 5 percent using sodium chloride particles, very high volatile particle removal of better than 98 percent using oil droplets, and no formation of sulfuric acid particles when using ammonium sulfate particles. The SPSS is a useful tool for researchers interested in characterizing the solid and volatile fraction of particles emitted from combustion sources.
Technical Paper

Development of an Intake Flow Based Model Calculating Real Time Exhaust Flow by Accounting for Filling and Emptying of the Engine Manifolds

2007-04-16
2007-01-0324
According to the ISO 16183 [1] protocol for heavy-duty diesel engines, particulate matter can be determined using a partial flow dilution system (PFDS). In order to control a PFDS, it is necessary to know the exact exhaust gas mass flow rate at the sample probe of the system at any given time. For the purpose of operating a PFDS with online control, a transformation time for the entire system (exhaust mass flow determination and partial flow adjustment) of equal or less than 300 ms is specified. In order to minimize the dynamic requirements for the PFDS a fast determination of the exhaust flow rate is necessary, which can be achieved most easily by using the intake flows (air + fuel flow) into the engine. This paper reports on the development and testing of an intake flow based model for calculating real time exhaust flow rate that accounts for the influence of the filling and emptying of the manifolds of a turbocharged diesel engine during dynamic operation.
Technical Paper

Marine Outboard and Personal Watercraft Engine Gaseous Emissions, and Particulate Emission Test Procedure Development

2004-09-27
2004-32-0093
The U.S. EPA and the California Air Resources Board have adopted standards to reduce emissions from recreational marine vessels. Existing regulations focus on reducing hydrocarbons. There are no regulations on particulate emissions; particulate is expected to be reduced as a side benefit of hydrocarbon control. The goal of this study was to develop a sampling methodology to measure particulate emissions from marine outboard and personal watercraft engines. Eight marine engines of various engine technologies and power output were tested. Emissions measured in this program included hydrocarbons, carbon monoxide, oxides of nitrogen. Particulate emissions will be presented in a follow-up paper.
Technical Paper

Particle Size Distribution and Mass Emissions from a Mining Diesel Engine Equipped with a Dry System Technologies Emission Control System

2003-05-19
2003-01-1893
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.
Technical Paper

Particle Free Exhaust Gas Recirculation by Molecular Diffusion: Proof of Concept

2003-03-03
2003-01-0769
This work included design and fabrication of a particle free exhaust gas recirculation element (PF-EGR-E) that included two concentric tubes, one for a clean air stream and the other for a simulated exhaust stream. The inner tube was a perforated tube to allow molecular diffusion between the two streams. The design and dimension of the PF-EGR-E was guided with the help of theoretical prediction of gas and particle diffusion. The goal was to build a PF-EGR-E that retains particles in a dilute exhaust stream while allowing maximum molecular exchange with the air stream. The performance of the PF-EGR-E was investigated using dilute diesel engine exhaust and clean air flowing in parallel at different flow and temperature levels.
Technical Paper

Particle Size Distribution from a Heavy-Duty Diesel Engine: Steady-State and Transient Emission Measurement Using Two Dilution Systems and Two Fuels

2003-03-03
2003-01-0285
Particle size distribution and number concentration were measured in the dilute exhaust of a heavy-duty diesel engine for steady-state and transient engine operation using two different dilution systems that included a full flow CVS that was coupled to an ejector pump (CVS-EP), and a double-ejector micro-dilution tunnel (DEMDT) that was connected to engine exhaust close to turbocharger outlet. Measurements were performed using a scanning mobility particle sizer (SMPS), an electrical low pressure impactor (ELPI), and a parallel flow diffusion battery (PFDB). Fuels with sulfur content of about 385 ppm and 1 ppm were used for this work. The PFDB performed well in measuring nanoparticles in the size range below 56 nm when compared with the SMPS. This was especially valid when a distinct log-normal size distribution in the size range below 56 nm in diameter, the upper size limit of the PFDB, was present.
Technical Paper

Hot Start Transient Emissions from a Mercedes OM 366 LA and a Detroit Diesel Operated on Chilean, California, and US 2D Fuels

2002-10-21
2002-01-2827
The emission performance of a 1997 Mercedes OM 366 LA medium heavy-duty diesel engine and a 1998 Detroit Diesel Corporation (DDC) Series 60 heavy heavy-duty diesel engine was investigated using the US EPA hot-start transient cycle using different candidate diesel fuels developed by the Empresa Nacional Del Petroleo (ENAP), the state-owned oil production and refining company of Chile. The aim of the work was to identify a clean diesel fuel that can be readily produced and reduces emissions from diesel engines in Chile, particularly in Santiago Metropolitan Area where air pollution is a serious problem. Using a Mercedes engine of the type found in Chile, several candidate fuel formulations were tested in both the Mercedes and DDC engines to identify leading candidate formulations that would effectively reduce emission in both traditional and modern technology engines.
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