Showing papers on "Diesel engine published in 1999"

Measurement of emissions from air pollution sources. 2. c1 through c30 organic compounds from medium duty diesel trucks

Abstract: Gas- and particle-phase tailpipe emissions from late-model medium duty diesel trucks are quantified using a two-stage dilution source sampling system. The diesel trucks are driven through the hot-start Federal Test Procedure (FTP) urban driving cycle on a transient chassis dynamometer. Emission rates of 52 gas-phase volatile hydrocarbons, 67 semivolatile and 28 particle-phase organic compounds, and 26 carbonyls are quantified along with fine particle mass and chemical composition. When all C_1−C_(13) carbonyls are combined, they account for 60% of the gas-phase organic compound mass emissions. Fine particulate matter emission rates and chemical composition are quantified simultaneously by two methods: a denuder/filter/PUF sampler and a traditional filter sampler. Both sampling techniques yield the same elemental carbon emission rate of 56 mg km^(-1) driven, but the particulate organic carbon emission rate determined by the denuder-based sampling technique is found to be 35% lower than the organic carbon mass collected by the traditional filter-based sampling technique due to a positive vapor-phase sorption artifact that affects the traditional filter sampling technique. The distribution of organic compounds in the diesel fuel used in this study is compared to the distribution of these compounds in the vehicle exhaust. Significant enrichment in the ratio of unsubstituted polycyclic aromatic hydrocarbons (PAH) to their methyl- and dimethyl-substituted homologues is observed in the tailpipe emissions relative to the fuel. Isoprenoids and tricyclic terpanes are quantified in the semivolatile organics emitted from diesel vehicles. When used in conjunction with data on the hopanes, steranes, and elemental carbon emitted, the isoprenoids and the tricyclic terpanes may help trace the presence of diesel exhaust in atmospheric samples.

Characterization of Polycyclic Aromatic Hydrocarbons in Motor Vehicle Fuels and Exhaust Emissions

Abstract: Motor vehicles are a significant source of polycyclic aromatic hydrocarbon (PAH) emissions. Improved understanding of the relationship between fuel composition and PAH emissions is needed to determine whether fuel reformulation is a viable approach for reducing PAH emissions. PAH concentrations were quantified in gasoline and diesel fuel samples collected in summer 1997 in northern California. Naphthalene was the predominant PAH in both fuels, with concentrations of up to 2600 mg L-1 in gasoline and 1600 mg L-1 in diesel fuel. Particle-phase PAH size distributions and exhaust emission factors were measured in two bores of a roadway tunnel. Emission factors were determined separately for light-duty vehicles and for heavy-duty diesel trucks, based on measurements of PAHs, CO, and CO2. Particle-phase emission factors, expressed per unit mass of fuel burned, ranged up to 21 μg kg-1 for benzo[ghi]perylene for light-duty vehicles and up to ∼1000 μg kg-1 for pyrene for heavy-duty diesel vehicles. Light-duty vehi...

Diesel engine reference book

Abstract: Part one - Theory Compression ignition engines Turbocharging Compound Engines Fuels Thermal loading. Part two - Modelling & Control Thermodynamics mathematical modelling Modern control. Part three - Engine Design Inlet & exhaust systems Balancing torsional vibration General design Fuel injection systems Bearings Pistons Governors Starting Gear Heat Exchangers Air cooling Crankcase explosions. Part four - Lubrication. Part five - Environmental factors Exhaust Smoke Exhaust emissions Automotive engine noise Large engine noise and vibration. Part six - Applications Passenger cars Trucks & buses Locomotives Turbocharged dual-fuel engines Marine high speed engines Marine low speed engines. Part seven - Testing and monitoring Engine test procedures Condition Monitoring. List of units and conversion tables. Index.

Experimental study of some performance parameters of a constant speed stationary diesel engine using ethanol--diesel blends as fuel

Abstract: The performance of a constant speed, stationary diesel engine using ethanol–diesel blends as fuel has been evaluated experimentally. The experiments were performed using 5, 10, 15 and 20% ethanol–diesel blends. Diesel fuel was used as a basis for comparison. The effect of using different blends of ethanol–diesel on engine horsepower, brake specific fuel consumption, brake thermal efficiency, the exhaust gas temperature and lubricating oil temperature were studied. The results indicate no significant power reduction in the engine operation on ethanol–diesel blends (up to 20%) at a 5% level of significance. Brake specific fuel consumption increased by up to 9% with an increase of ethanol up to 20% in the blends as compared to diesel alone. The exhaust gas temperature, lubricating oil temperatures and exhaust emissions (CO and Nox) were lower with operations on ethanol–diesel blends as compared to operation on diesel.

Composition of light-duty motor vehicle exhaust particulate matter in the denver, colorado area

Abstract: A study to characterize particulate matter emissions from 195 in-use gasoline and diesel passenger vehicles was conducted during the summer of 1996 and the winter of 1997 in the Denver, Colorado region. Vehicles were tested as received on chassis dynamometers using the Federal Test Procedure (FTP) Urban Dynamometer Driving Schedule (UDDS). Both PM-10 and regulated emissions were measured for each phase of the UDDS. Approximately 88% of the PM-10 collected was carbonaceous material, of which the average organic fraction was 0.7 for gasoline vehicles and 0.4 for diesel vehicles. This suggests that the organic carbon (OC) to elemental carbon (EC) split may be useful in separating light-duty gasoline from diesel PM emissions. Sulfate emission rates averaged 0.45 and 3.51 mg/mi for gasoline and diesel vehicles, indicating that the EPA's mobile emissions model overpredicts sulfate emission rates. Elements identified by X-ray fluorescence averaged between 3 and 9% of the PM-10 mass. Polynuclear aromatic hydrocar...

Bronchoalveolar inflammation after exposure to diesel exhaust: comparison between unfiltered and particle trap filtered exhaust.

Abstract: OBJECTIVES: Air pollution particulates have been identified as having adverse effects on respiratory health. The present study was undertaken to further clarify the effects of diesel exhaust on bronchoalveolar cells and soluble components in normal healthy subjects. The study was also designed to evaluate whether a ceramic particle trap at the end of the tail pipe, from an idling engine, would reduce indices of airway inflammation. METHODS: The study comprised three exposures in all 10 healthy never smoking subjects; air, diluted diesel exhaust, and diluted diesel exhaust filtered with a ceramic particle trap. The exposures were given for 1 hour in randomised order about 3 weeks apart. The diesel exhaust exposure apperatus has previously been carefully developed and evaluated. Bronchoalveolar lavage was performed 24 hours after exposures and the lavage fluids from the bronchial and bronchoalveolar region were analysed for cells and soluble components. RESULTS: The particle trap reduced the mean steady state number of particles by 50%, but the concentrations of the other measured compounds were almost unchanged. It was found that diesel exhaust caused an increase in neutrophils in airway lavage, together with an adverse influence on the phagocytosis by alveolar macrophages in vitro. Furthermore, the diesel exhaust was found to be able to induce a migration of alveolar macrophages into the airspaces, together with reduction in CD3+CD25+ cells. (CD = cluster of differentiation) The use of the specific ceramic particle trap at the end of the tail pipe was not sufficient to completely abolish these effects when interacting with the exhaust from an idling vehicle. CONCLUSIONS: The current study showed that exposure to diesel exhaust may induce neutrophil and alveolar macrophage recruitment into the airways and suppress alveolar macrophage function. The particle trap did not cause significant reduction of effects induced by diesel exhaust compared with unfiltered diesel exhaust. Further studies are warranted to evaluate more efficient treatment devices to reduce adverse reactions to diesel exhaust in the airways.

Neural Network-Based Diesel Engine Emissions Prediction Using In-Cylinder Combustion Pressure

Abstract: This paper explores the feasibility of using in-cylinder pressure-based variables to predict gaseous exhaust emissions levels from a Navistar T444 direct injection diesel engine through the use of neural networks. The networks were trained using in-cylinder pressure derived variables generated at steady state conditions over a wide speed and load test matrix. The networks were then validated on previously "unseen" real-time data obtained from the Federal Test Procedure cycle through the use of a high speed digital signal processor data acquisition system. Once fully trained, the DSP-based system developed in this work allows the real-time prediction of NOX and CO2 emissions from this engine on a cycle-by-cycle basis without requiring emissions measurement.

Method and apparatus for emission control

Abstract: A converter for purifying exhaust gases from lean-burn engines, in particular for controlling the amount of NO x and soot from a diesel engine in transient operation such as a vehicle. The converter contains a catalyst bed with a catalyst effective for NO x reduction with a chemical reductant when the catalyst bed is with a certain temperature window and when the ratio between the molar amount of chemical reductant and NO x is above a certain minimum ratio. The catalyst bed is heated or cooled to a temperature within the temperature window and a switching valve is provided for reverse flowing the exhaust gases through the converter to maintain the catalyst bed at a temperature within the temperature window for a longer time than is possible with a conventional non-flow-reversing converter. A reductant delivery system adds chemical reductant to the exhaust gases in an appropriate amount so that the ratio between the molar amount of chemical reductant and NO x is above the certain minimum ratio when the exhaust gases pass over the catalyst bed. A soot trap may be provided in series with the catalyst bed in the converter, said reverse flowing of the exhaust gases through converter heating and continuously maintaining the soot trap at or above the ignition temperature of the soot.

Environmental applications of low-temperature plasmas

Abstract: Treatment of NOx in diesel engine exhaust represents a big opportunity for the environmental application of low-temperature plasmas. This paper discusses the effect of gas composition on the NOx conversion chemistry in a plasma. It is shown that the plasma by itself cannot chemically reduce NOx to N2 in the highly oxidizing environment of a diesel engine exhaust. To implement the reduction of NOx to N2, it is necessary to combine the plasma with a heterogeneous process that can chemically reduce NO2 to N2. Data is presented that demonstrates how the selective partial oxidation of NO to NO2 in a plasma can be utilized to enhance the selective reduction of NOx to N2 by a catalyst.

Accelerated oxidation processes in biodiesel

Abstract: Biodiesel is an alternative fuel for diesel engines that can be produced from renewable feedstocks such as vegetable oil and animal fats. These feedstocks are reacted with an alcohol to produce alkyl monoesters that can be used in conventional diesel engines with little or no modification. Biodiesel, especially if produced from highly unsaturated oils, oxidizes more rapidly than diesel fuel. This article reports the results of experiments to track the chemical and physical changes that occur in biodiesel as it oxidizes. These results show the impact of time, oxygen flow rate, temperature, metals, and feedstock type on the rate of oxidation. Blending with diesel fuel and the addition of antioxidants are explored also. The data indicate that without antioxidants, biodiesel will oxidize very quickly at temperatures typical of diesel engines. This oxidation results in increases in peroxide value, acid value, and viscosity. While the peroxide value generally reaches a plateau of about 350 meq/kg ester, the acid value and viscosity increase monotonically as oxidation proceeds.

Transient Turbulent Gaseous Fuel Jets for Diesel Engines

Abstract: Existing data on transient turbulent jet injection in to large chambers demonstrates self-similar behavior under a wide range of conditions including compressibility, thermal and species diffusion, and nozzle under expansion. The Jet penetration distance well downstream of the virtual origin is proportional to the square root of the time and the fourth root of the ratio of nozzle exit momentum flow rate to chamber density. The constant of proportionality has been evaluated by invoking the concept of Turner that the flow can be modeled as a steady jet headed by a spherical vortex. Using incompressible transient jet observations to determine the asymptotically constant ratio of maximum jet width to penetration distance, and the steady jet entrainment results of Ricou and Spalding, it is shown that the penetration constant is 3 ± 0.1. This value is shown to hold for compressible flows also, with substantial thermal and species diffusion, and even with transient jets from highly under-expanded in which, as in diesel engine chambers with gaseous fuel injection, the jet is directed at a small angle to one wall of the chamber. In these tests, with under expanded nozzles. Observations of transient jet injection have been made in a chamber in which, as in diesel engine chambers with gaseous fuel injection, the jet is directed at a small angle to one wall of the chamber. In these tests, with under-expanded nozzles it was found that at high nozzle pressure ratios, depending on the jet injection angle, the jet penetration can be consistent with a penetration constant of 3. At low pressure ratios the presence of the wall noticeably retards the penetration of the jet.

Determination of voc-components in the exhaust of gasoline and diesel passenger cars

Abstract: The composition of VOC (volatile organic compounds) emissions from in-use passenger cars with different engine types, ie cars with diesel engines, cars with petrol engines equipped with three-way-catalysts, and cars with petrol engines without catalysts was determined. Five cars of each engine type have been measured on a chassis dynamometer under conditions of the US FTP 75 test procedure and the "Autobahn" test developed by TUV Rheinland. Measurements of C2 and C10 hydrocarbons were made with a GC-FID system. In addition, samples on DNPH cartridges were taken and analysed by means of a HPLC-system for the determination of aldehydes and ketones. The influence of cold/warm-conditions on the VOC composition was determined. In the case of cars with diesel engines as well as for the petrol driven cars without exhaust treatment, the effect caused by the cold start only led to minor changes in the VOC composition. A similar behaviour was observed for these car types at higher speeds. In contrast to the cars without catalysts the cars with three-way-catalysts showed a great variability of the VOC composition. During the cold start phase the aromatic compounds and the alkanes yielded the main fraction of the VOC. During the warm phase the less reactive alkanes were predominant. With increasing mean velocities the VOC composition changed in favour of the more reactive compounds. (A) For the covering abstract see IRRD E101903.

Methods for engine supervision and control based on cylinder pressure information

Abstract: The increasing demands for low emissions and low fuel consumption in modern combustion engines require improved methods for online diagnosis and best possible control of the combustion process. It is demonstrated that the cylinder pressure signal can successfully be used for this task. After introduction of some theoretical background, several application examples are presented: an online supervision of fuel injection, some results on feedforward emission control, and a concept for feedback control of spark timing. Experimental results obtained from stock car diesel and spark ignition engines are included to support the automation concepts.

Effects of thermal barrier coating on a turbocharged diesel engine performance

Abstract: Thermal barrier ceramic coatings are successfully used for applications in diesel engines and in the combustion chamber of gas turbine engines, e.g., for nozzle guide vanes, turbine blades, cylinder liners and heads. An experimental investigation into the effects of ceramic coatings on the performance of a diesel engine and exhaust emissions was conducted. Ceramic coatings can eliminate visible smoke, inhibit the formation of NOx, reduce CO and particulate emissions, and improve combustion efficiency. The performance of the diesel ceramic coating was tested on a hydraulic engine dynamometer. The coatings are being evaluated for their ability to control particulate emissions, for emissions in exhaust gases for smoke, horsepower, speed and fuel rate. CO and hydrocarbon levels were lower than baseline levels.

Dynamic Field Measurements of Submicron Particles from Diesel Engines

Abstract: The authors present new tools and a complete setup with which the submicron particles, emitted from combustion processes, can be measured and classified according to their chemical nature even in the field. Diesel engines are the predominant source of these particles in the industrialized countries. The setup comprises an exhaust conditioning part including means for precipitation of the coarse particle fraction, dilution, and removal of volatile material. The submicron particles are detected with three different sensors: one for particle number concentration (condensation particle counter, CPC), one for the particle Fuchs-surface, and one that responds specifically to the carbonaceous particles. These sensors possess a short response time so that transients such as those occurring in the free acceleration mode may be observed as well. Experiments on a conventional engine test bench demonstrate the tools. The test results are highly reassuring. Correct handling of the volatile fraction is essential to avoid severe artifacts from gas to particle reactions particularly in exhaust from engines equipped with particle traps.

Method for converting exhaust gases from a diesel engine using nitrogen oxide absorbent

Abstract: The invention is a method of treating exhaust gases generated by a diesel engine by locating two catalyst components in the engine exhaust gas passage. The first catalyst component which exposed to oxidizing diesel exhaust is located nearest to the engine and is a nitrogen oxide absorbent made of support material carrying precious metal. The second component is a catalyst such as a lean-NOx catalyst or a selective reduction catalyst which is capable of converting the exhaust gas passing over it including reducing the nitrogen oxides desorbed from the first component into nitrogen (N2) or nitrous oxide (N2O). Materials like hydrocarbons or ammonia or urea may be injected into the vicinity of the second catalyst component to aid in the reduction.

The effect of biodiesel feedstock on regulated emissions in chassis dynamometer tests of a pickup truck.

Abstract: Six different vegetable oil esters (coconut ethyl ester, used hydrogenated soy methyl ester, rapeseed ethyl ester, mustard ethyl ester, safflower ethyl ester, and a commercial methyl ester of soy oil) were selected to represent a range of iodine numbers from 7.88 to 133. These vegetable oil esters were tested neat and in 20% biodiesel/80% diesel blends in comparison with low sulfur diesel fuel for the effect on regulated emissions. The test vehicle was a pickup truck with a 5.9 L turbo-charged and inter-cooled direct injection diesel engine. The emissions tests were conducted at the Los Angeles County Metropolitan Transit Authority Emissions Testing Facility on a chassis dynamometer. It was found that lower iodine numbers correlated with reduced nitrogen oxides (NOx). As iodine number increased from 7.88 to 129.5 the NOx increased 29.3%. Fatty acids with two double bonds appeared to have more effect on increasing NOx emissions than did fatty acids with one double bond. Changes in carbon monoxide (CO), hydrocarbons (HC), and particulate matter (PM) were not linearly correlated with iodine number. It is apparent that the type of feedstock oil affects the characteristics of the biodiesel fuel. The most obvious difference is that the pour point changes with fatty acid composition, however, other fuel characteristics, some of which effect combustion, are also changed. This article reports on a study of biodiesel iodine number on changes in regulated emissions. The results of this and similar studies provide information for developing triglycerides specifically for optimum use in biodiesel. Modern chemical processes and/or plant breeding should make this possible.

Efficient EGR Technology for Future HD Diesel Engine Emission Targets

Abstract: Different systems for achieving short-route cooled EGR on turbocharged and aftercooled heavy-duty diesel engines have been tested on a 12 litre 315 kW engine with 4 valves per cylinder and an electronically controlled unit pump fuel injection system. In all of these systems the exhaust gas was tapped off before the turbine, cooled and mixed with the intake air after the compressor and aftercooler. The systems differed (mainly) in the method used to set up a positive pressure difference across the EGR circuit. This was done either by the use of an exhaust back pressure valve in the exhaust, or by using a turbocharger with variable nozzle turbine (VNT) geometry, or by combining such a VNT turbocharger with a venturi-mixer that was positioned in the intake manifold such as to provide extra suction power to the EGR gas. The emissions behaviour and efficiency with these different EGR systems were tested in a number of engine working points, including key points of the AVL 8-mode US FTP cycle simulation. The results indicate that for achieving 1998 emission levels, a VNT only would be the most efficient solution. For achieving 2004 emission levels, combining the VNT with a venturi-mixer could give a further fuel consumption benefit. Particulate matter emisisons will however be unacceptable, making the use of additional particulate reducing technology necessary. A measure of venturi-mixer effienciency is proposed and a new, compact and efficient venturi-mixer design is presented. Results from flow tests are given and compared with results from CFD calculations.

Process and apparatus for treating combustion exhaust gas

Abstract: A system and method for the control of emissions from a diesel engine exhaust, comprises a catalyst (14) to convert NO to NO2, a filter (16) to trap soot and hold it for combustion with the NO2, and a NOx absorber (28), with means to regenerate the NOx absorber by injecting reductant or other reactant (injector 18) upstream of the absorber, and at least during regeneration, passing the exhaust gases leaving the absorber through a three-way catalyst (30).

Catalyst and method for reducing exhaust gas emissions

Abstract: An apparatus useful to treat exhaust gas stream, including diesel engine exhaust. The exhaust stream passes from an exhaust outlet to a catalyzed filter in communication with the exhaust outlet. The catalyzed filter comprises a first catalyst which comprises a first platinum group metal; a first cerium component; and preferably a zirconium component. There can be a second catalyst in communication with the first catalyst, the second catalyst comprises a second cerium component.

Methylal and Methylal-Diesel Blended Fuels for Use in Compression-Ignition Engines

Abstract: Gas-to-liquids catalytic conversion technologies show promise for liberating stranded natural gas reserves and for achieving energy diversity worldwide Some gas-to-liquids products are used as transportation fuels and as blendstocks for upgrading crude derived fuels Methylal (CH{sub 3}-O-CH{sub 2}-O-CH{sub 3}) also known as dimethoxymethane or DMM, is a gas-to-liquid chemical that has been evaluated for use as a diesel fuel component Methylal contains 42% oxygen by weight and is soluble in diesel fuel The physical and chemical properties of neat methylal and for blends of methylal in conventional diesel fuel are presented Methylal was found to be more volatile than diesel fuel, and special precautions for distribution and fuel tank storage are discussed Steady state engine tests were also performed using an unmodified Cummins 859 turbocharged diesel engine to examine the effect of methylal blend concentration on performance and emissions Substantial reductions of particulate matter emissions h ave been demonstrated 3r IO to 30% blends of methylal in diesel fuel This research indicates that methylal may be an effective blendstock for diesel fuel provided design changes are made to vehicle fuel handling systems