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Technical Paper

Impact of Lubricant Oil on Regulated Emissions of a Light-Duty Mercedes-Benz OM611 CIDI-Engine

2001-05-07
2001-01-1901
The Partnership for a New Generation Vehicle (PNGV) has identified the compression-ignition, direct-injection (CIDI) engine as a promising technology in meeting the PNGV goal of 80 miles per gallon for a prototype mid-size sedan by 2004. Challenges remain in reducing the emission levels of the CIDI-engine to meet future emission standards. The objective of this project was to perform an initial screening of crank case lubricant contribution to regulated engine-out emissions, particularly when low particulate forming diesel fuel formulations are used. The test engine was the Mercedes-Benz OM611, the test oils were a mineral SAE 5W30, a synthetic (PAO based) SAE 5W30, and a synthetic (PAO based) SAE 15W50, and the test fuels were a California-like certification fuel and an alternative oxygenated diesel fuel.
Technical Paper

U.S. Army Investigation of Diesel Exhaust Emissions Using JP-8 Fuels with Varying Sulfur Content

1996-10-01
961981
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.
Technical Paper

Diesel Fuel Ignition Quality as Determined in the Ignition Quality Tester (IQT) - Part II

1997-05-01
971636
A combustion-based analytical method, initially developed by the Southwest Research Institute (SwRI) and referred to as the Constant Volume Combustion Apparatus (CVCA), has been further researched/developed by an SwRI licensee (Advanced Engine Technology Ltd.). This R&D has resulted in a diesel fuel Ignition Quality Tester (IQT) that permits rapid and precise determination of the ignition quality of middle distillate and alternative fuels. Its features, such as low fuel volume requirement, complete test automation, and self-diagnosis, make it highly suitable for commercial oil industry and research applications. A preliminary investigation, reported in SAE paper 961182, has shown that the IQT results are highly correlated to the ASTM D-613 cetane number (CN). The objective of this paper is to report on efforts to further refine the original CN model and report on improvements to the IQT fuel injection system.
Technical Paper

The Effects of Fuel Properties on Emissions from a 2.5gm NOx Heavy-Duty Diesel Engine

1998-10-19
982491
The engine selected for this work was a Caterpillar 3176 engine. Engine exhaust emissions, performance, and heat release rates were measured as functions of engine configuration, engine speed and load. Two engine configurations were used, a standard 1994 design and a 1994 configuration with EGR designed to achieve a NOx emissions level of 2.5 gm/hp-hr. Measurements were performed at 7 different steady-state, speed-load conditions on thirteen different test fuels. The fuel matrix was statistically designed to independently examine the effects of the targeted fuel properties. Cetane number was varied from 40 to 55, using both natural cetane number and cetane percent improver additives. Aromatic content ranged from 10 to 30 percent in two different forms, one in which the aromatics were predominantly mono-aromatic species and the other, where a significant fraction of the aromatics were either di- or tri-aromatics.
Technical Paper

Reactivity Comparison of Exhaust Emissions from Heavy-Duty Engines Operating on Gasoline, Diesel, and Alternative Fuels

1995-10-01
952442
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.
Technical Paper

Survey of Low Sulfur Diesel Fuels and Aviation Kerosenes from U.S. Military Installations

1995-10-01
952369
In support of the Department of Defense goal to streamline procurements, the Army recently decided to discontinue use of VV-F-800D as the purchase specification for diesel fuel being supplied to continental United States military installations. The Army will instead issue a commercial item description for direct fuel deliveries under the Post-Camp-Station (PCS) contract bulletin program. In parallel, the Defense Fuel Supply Center and the U.S. Army Mobility Technology Center-Belvoir (at Ft. Belvoir, VA) initiated a fuel survey with the primary objective to assess the general quality and lubricity characteristics of low sulfur diesel fuels being supplied to military installations under the PCS system. Under this project, diesel fuel delivery samples were obtained from selected military installations and analyzed according to a predetermined protocol.
Technical Paper

Combustion and Emissions Characteristics of Minimally Processed Methanol in a Diesel Engine Without Ignition Assist

1994-03-01
940326
Mixtures of methanol, water and heavier alcohols, simulating “raw’ methanol at various levels of processing, were tested in a constant volume combustion apparatus (CVCA) and in a single-cylinder, direct-injection diesel engine. The ignition characteristics determined in the CVCA indicated that the heavier alcohols have beneficial effects on the auto-ignition quality of the fuels, as compared to pure methanol. Water, at up up to 10 percent by volume, has little effect on the ignition quality. In all cases, however, the cetane numbers of the alcohol mixtures were very low. The same fuels were tested in a single cylinder engine, set-up in a configuration similar to current two-valve DI engines, except that the compression ratio was increased to 19:1. Pure methanol and five different blends of alcohols and water were tested in the engine at five different speed-load conditions.
Technical Paper

Effects of Cetane Number, Aromatics, and Oxygenates on Emissions From a 1994 Heavy-Duty Diesel Engine With Exhaust Catalyst

1995-02-01
950250
A Coordinating Research Council sponsored test program was conducted to determine the effects of diesel fuel properties on emissions from two heavy-duty diesel engines designed to meet EPA emission requirements for 1994. Results for a prototype 1994 DDC Series 60 were reported in SAE Paper 941020. This paper reports the results from a prototype 1994 Navistar DTA-466 engine equipped with an exhaust catalyst. A set of ten fuels having specific variations in cetane number, aromatics, and oxygen were used to study effects of these fuel properties on emissions. Using glycol diether compounds as an oxygenated additive, selected diesel fuels were treated to obtain 2 and 4 mass percent oxygen. Cetane number was increased for selected fuels using a cetane improver. Emissions were measured during transient FTP operation of the Navistar engine tuned for a nominal 5 g/hp-hr NOx, then repeated using a 4 g/hp-hr NOx calibration.
Technical Paper

Effects of Cetane Number on Emissions From a Prototype 1998 Heavy-Duty Diesel Engine

1995-02-01
950251
As stringent emission regulations further constrain engine manufacturers by tightening both NOx and particulate emission limits, a knowledge of fuel effects becomes more important than ever. Among the fuel properties that affect heavy-duty diesel engine emissions, cetane number can be very important. Part of the CRC-APRAC VE-10 Project was developed to quantify the effects of cetane number on NOx and other emissions from a prototype 1998 Detroit Diesel Series 60. Three fuels with different natural cetane number (41, 45, 52) were treated with several levels and types of cetane improvers to study a range of cetane number from 40 to 60. Statistical analysis was used to define how regulated emissions from this prototype 1998 engine decreased with chemically-induced cetane number increase. Variation of HC, CO, NOx, and PM were modeled using a combination of a fuel's naturally-occurring cetane number and its total cetane number obtained with cetane improver.
Technical Paper

Effects of Cetane Number, Cetane Improver, Aromatics, and Oxygenates on 1994 Heavy-Duty Diesel Engine Emissions

1994-03-01
941020
Several studies have investigated the effects of diesel fuel properties on heavy-duty engine emissions. The objective of this CRC-sponsored test program was to determine the effects of oxygenated diesel fuel, and to further investigate the effects of cetane number and aromatic content on emissions from a heavy-duty engine set to obtain transient NOx emissions below 5 and then 4 g/hp-hr. A fuel set was developed with controlled variations in cetane number, aromatics, and oxygen to superette their effects on emissions. Ignition improver was used to increase cetane number of several fuels. Oxygenated diesel fuel was achieved by adding a “glyme” compound to selected fuels to obtain 2 and 4 mass percent oxygen concentrations. With these fuels, emissions were measured over the EPA transient FTP using a prototype 1994 DDC Series 60 tuned for 5 and then 4 g/hp-hr NOx. No exhaust aftertreatment device was used on this engine.
Technical Paper

Relationships Between Fuel Properties and Composition and Diesel Engine Combustion Performance and Emissions

1994-03-01
941018
Five different diesel fuel feedstocks were processed to two levels of aromatic (0.05 sulfur, and then 10 percent) content. These materials were distilled into 6 to 8 narrow boiling range fractions that were each characterized in terms of the properties and composition. The fractions were also tested at five different speed load conditions in a single cylinder engine where high speed combustion data and emissions measurements were obtained. Linear regression analysis was used to develop relationships between the properties and composition, and the combustion and emissions characteristics as determined in the engine. The results are presented in the form of the regression equations and discussed in terms of the relative importance of the various properties in controlling the combustion and emissions characteristics. The results of these analysis confirm the importance of aromatic content on the cetane number, the smoke and the NOx emissions.
Technical Paper

Diesel Fuel Ignition Quality as Determined in the Ignition Quality Tester (IQT)

1996-05-01
961182
A combustion-based analytical method, initially developed by the Southwest Research Institute (SwRI) referred to as the Constant Volume Combustion Apparatus (CVCA), has been further researched/developed by an SwRI licensee (Advanced Engine Technology Ltd.) as an Ignition Quality Tester (IQT) for laboratories and refineries. The IQT software/hardware system permits rapid and precise determination of ignition quality for middle distillate fuels. Its features, such as low fuel volume requirement, complete test automation, and self-diagnosis, make it highly suitable for commercial oil industry and research applications. Operating and test conditions were examined in the context of providing a high correlation with cetane number (CN), as determined by the ASTM D-613 method. Preliminary investigation indicates that the IQT results are highly repeatable (± 0.30 CN), providing a high sensitivity to CN variation over the 33 to 58 CN range.
Technical Paper

Homogeneous Charge Compression Ignition of Diesel Fuel

1996-05-01
961160
A single-cylinder, direct-injection diesel engine was modified to operate on compression ignition of homogenous mixtures of diesel fuel and air. Previous work has indicated that extremely low emissions and high efficiencies are possible if ignition of homogeneous fuel-air mixtures is accomplished. The limitations of this approach were reported to be misfire and knock. These same observations were verified in the current work. The variables examined in this study included air-fuel ratio, compression ratio, fresh intake air temperature, exhaust gas recirculation rate, and intake mixture temperatures. The results suggested that controlled homogeneous charge compression ignition (HCCI) is possible. Compression ratio, EGR rate, and air fuel ratio are the practical controlling factors in achieving satisfactory operation. It was found that satisfactory power settings are possible with high EGR rates and stoichiometric fuel-air mixtures.
Technical Paper

Coal-Water-Slurry Autoignition in a High-Speed Detroit Diesel Engine

1994-10-01
941907
Autoignition of coal-water-slurry (CWS) fuel in a two-stroke engine operating at 1900 RPM has been achieved. A Pump-Line-Nozzle (PLN) injection system, delivering 400mm3/injection of CWS, was installed in one modified cylinder of a Detroit Diesel Corporation (DI)C) 8V-149TI engine, while the other seven cylinders remained configured for diesel fuel. Coal Combustion was sustained by maintaining high gas and surface temperatures with a combination of hot residual gases, warm inlet air admission, ceramic insulated components and increased compression ratio. The coal-fueled cylinder generated 85kW indicated power (80 percent of rated power), and lower NOx levels with a combustion efficiency of 99.2 percent.
Technical Paper

EGR System Integration on a Pump Line-Nozzle Engine

1998-02-23
980181
The minimum oxides of nitrogen (NOx) emissions over the U.S. Federal Test Procedure (FTP) using exhaust gas recirculation (EGR) were investigated on a heavy-duty diesel engine featuring a pump-line-nozzle fuel injection system. Due to the technical merits of electronic fuel injection systems, most accounts of EGR system development for heavy-duty diesel engines have focused on these types of engines and not engines with mechanical fuel systems. This work details use of a high-pressure-loop EGR configuration and a novel, computer-controlled, EGR valve that allowed for optimizing the EGR rate as a function of speed and load on a 6L, turbo-charged/intercooled engine. Cycle NOx levels were reduced nearly 50 percent to 2.3 g/hp-hr using conventional diesel fuel and application of only EGR, but particulates increased nearly three-fold even with the standard oxidation catalyst employed.
Technical Paper

Homogeneous Charge Compression Ignition (HCCI) of Diesel Fuel

1997-05-01
971676
This paper describes the ongoing homogeneous charge compression ignition (HCCI) research being carried out at Southwest Research Institute (SwRI). Summaries of the results of testing to date are presented and discussed. HCCI is a process whereby a premixed charge of diesel fuel and air is admitted into the power cylinder and compression ignited. Ignition occurs homogeneously throughout the cylinder. HCCI reduces flame temperatures and oxides of nitrogen (NOx) emissions. The lack of fuel rich zones within the cylinder eliminates soot formation (1-pull Bosch smoke numbers of 0, 5-pull = 0). The limits of HCCI start of combustion timing are defined by knock before top dead center (BTDC) and misfire after top dead center (ATDC). Stable and repeatable HCCI combustion has been demonstrated over a wide range of air-fuel (A/F) ratios, intake temperatures, compression ratios (CR), exhaust gas recirculation (EGR) rates, and for two fuels. A/F ratios of 14 to 80 are possible.
Technical Paper

Compatibility of Elastomers and Metals in Biodiesel Fuel Blends

1997-05-01
971690
Alternative fuels are being evaluated in automotive applications in both commercial and government fleets in an effort to reduce emissions and United States dependence on diesel fuel. Vehicles and equipment have been operated using 100 percent biodiesel and various blends of biodiesel and diesel fuel in a variety of applications, including farming equipment and transit buses. This government study investigates the compatibility of four base fuels and six blends with elastomer and metallic components commonly found in fuel systems. The physical properties of the elastomers were measured according to American Society of Testing and Materials (ASTM) D 471, “Standard Test Method for Rubber Property-Effect of Liquids,” and ASTM D 412, “Standard Test Methods for Rubber Properties in Tension.” These evaluations were performed at 51.7°C for 0, 22, 70, and 694 hours. Tensile strength, hardness, swell, and elongation were determined for all specimens.
Technical Paper

Analysis of a Hybrid Powertrain for Heavy Duty Trucks

1995-11-01
952585
Heavy duty trucks account for about 50 percent of the NOx burden in urban areas and consume about 20 percent of the national transportation fuel in the United States. There is a continuing need to reduce emissions and fuel consumption. Much of the focus of current work is on engine development as a stand-alone subsystem. While this has yielded impressive gains so far, further improvement in emissions or engine efficiency is unlikely in a cost effective manner. Consequently, an integrated approach looking at the whole powertrain is required. A computer model of the heavy duty truck system was built and evaluated. The model includes both conventional and hybrid powertrains. It uses a series of interacting sub-models for the vehicle, transmission, engine, exhaust aftertreatment and braking energy recovery/storage devices. A specified driving cycle is used to calculate the power requirements at the wheels and energy flow and inefficiencies throughout the drivetrain.
Technical Paper

Shale-Derived Diesel Test Fuels for Utilization Studies

1988-10-01
881627
An untreated heavy distillate fraction from a mixture of Geokinetics and Occidental shale oils was hydrogenated at three levels of severity. The three products showed good ignition quality and met most of the current specifications for No. 2-D diesel fuel. Nitrogen contents ranged from 250 to 1890 parts per million. Good oxidation stability was obtained in the product with lowest nitrogen content. Stability of the other two products was marginal but would be improved by use of an antioxidant additive. The test fuels will be used in engine and combustion studies.
Technical Paper

Engine and Constant Volume Bomb Studies of Diesel ignition and Combustion

1988-10-01
881626
Changing fuel quality, increasingly stringent exhaust emission standards, demands for higher efficiency, and the trend towards higher specific output, all contribute to the need for a better understanding of the ignition process in diesel engines. In addition to the impact on the combustion process and the resulting performance and emissions, the ignition process controls the startability of the engine, which, in turn, governs the required compressions ratio and several of the other engine design parameters. The importance of the ignition process is reflected in the fact that the only combustion property that is specified for diesel fuel is the ignition delay time as indicated by the cetane number. The objective of the work described in this paper was to determine the relationship between the ignition process as it occurs in an actual engine, to ignition in a constant volume combustion bomb.
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