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Viewing 1 to 30 of 1735
1990-02-01
Technical Paper
900443
Wolfgang F. Wachter
A heavy duty diesel engine was developed to meet US-EPA 1991 emission standards, and heavy duty diesel transient cycles (HDDTC) were run with different engine versions. Actual engine data such as speed, torque, air mass flow, gaseous emissions, temperatures and the carbon- and HC-fraction of particulate matter were transiently recorded. For each limited pollutant the phases of the HDDTC were identified, where a major contribution to the total cycle emission occurs. Comparing different engine versions, strategies for further reduction of emissions were elaborated. Emphasis was placed on particulate matter.
1990-02-01
Technical Paper
900440
Makoto Ikegami, Masanori Fukuda, Yoshinobu Yoshihara, Jiro Kaneko
This paper deals with the effect of combustion chamber shape and the role of pressurized injection in high-speed direct-injection diesel engines. First, the previously reported good performance and emission characteristics of the reentrant chamber were confirmed in a single-cylinder engine test. To obtain a better insight into this excellence, a high-speed gas-sampling method was applied to determine the local fuel-air equivalence ratios and mass fractions of substances having higher boiling points during combustion. The results showed that even at a retarded injection the reentrant chamber suppressed the outflow of gas into the clearance space from containing a lot of higher-boiling-point substances, like raw fuel and carbonaceous matter, thereby assuring a less heterogeneous state than the ordinary deep-bowl chamber. This is attributed partly to the suppressed outflow of unburnt gas from the cavity and partly to the enhanced mixing near the entrance.
1990-02-01
Technical Paper
900386
Qiqing Jiang, Pradheepram Ottikkutti, Jon VanGerpen, Delmar VanMeter
The effects of ethanol fumigation on the performance and emissions of a four-cylinder, turbocharged diesel engine have been investigated. The effects of speed, load, alcohol proof, and the fraction of the engine's power supplied by the alcohol are presented. Comparisons are made with methanol and water injection. Analysis of the results shows that methanol and ethanol have almost identical effects when compared on an equal energy basis that includes the enthalpy of vaporization of the alcohol and water. The indicated thermal efficiencies of the alcohol and diesel fuel are separated, showing that the alcohol utilization is not affected by proof or fraction of power contributed by alcohol. A dramatic reduction in NOx emission suggests that fumigation may have potential as an emission control technique in diesel engines. A stoichiometric, adiabatic flame temperature is calculated and used to determine the contribution of lower combustion temperature to the decrease in NOx emission.
1990-02-01
Technical Paper
900394
A. K. Oppenheim, N. J. Beck, K. Hom, J. A. Maxson, H. E. Stewart
The methodology put forth in this paper stems from the premise that the primary reason for the generation of major pollutants by diesel engines, particulates and nitric oxides, is associated with over-reliance upon diffusion flames to carry out the process of combustion. Specific means are, therefore, proposed to inhibit their formation. This consists of refinements involving the use of either hollow cone spray injectors or air blast atomizers. Concomitantly, the process of combustion is staged by either regulating the rate of injection or employing a number of consecutively activated injectors per cylinder under a microprocessor command, while regions of high temperature peaks are distributed throughout the charge and kept at a relatively low level by exploiting the large scale vortex structure of turbulent pulsed jets combined with residual gas recirculation.
1990-02-01
Technical Paper
900396
M. L Arold, C. Espey, T. A. Litzinger, D. A. Santavicca, R. J. Santoro
A research DI Diesel engine has been constructed for the optical investigation of in-cylinder flow fields, spray, combustion and emissions phenomena. This ported engine, built on a CFR crankcase, permits complete optical access to the combustion chamber which is located in the head of the engine. In the present study, combustion chambers with square and round cross-sections were used, and non-swirling and swirling flows were investigated. The flow fields for the various configurations were measured in the motored engine using laser Doppler velocimetry (LDV) to establish the conditions that existed prior to fuel injection. High speed movies were used to observe the spray and combustion processes with and without swirl in the two combustion chambers. Distinctly different patterns of the spray plumes and visible light emission are observed for the two flow conditions, but no major differences were observed with changes in bowl geometry under similar flow conditions.
1990-02-01
Technical Paper
900398
Joseph Shakal, Jay K. Martin
- Pilot injection and two other forms of auxiliary fuel introduction have been studied for their effects on diesel engine combustion and emissions. A two-stroke diesel has been equipped with an electronic solenoid-controlled unit injector such that the injector can operate with pilot injection. In addition, the engine has been fitted with experimental air-blast atomizing injectors in the inlet port and intake manifold. In-cylinder pressure, Bosch smoke, exhaust hydrocarbons, NO and NOx emissions measurements have been made for a range of engine conditions. In addition, two fuels have been tested to observe the effects of fuel blend on the auxiliary fuel behavior. In general, the effect of auxiliary fuel introduction is to reduce ignition delay and rate-of-pressure rise. This tends to result in a decrease in NO emissions. Unburned hydrocarbons and smoke tend to increase, although not in every case.
1990-02-01
Technical Paper
900399
M. R. Ahmadi, D. B. Kittelson, D. D. Brehob
A modified CFR Cetane engine was used to analyze combustion characteristics and emissions of minimally processed coal liquids (MPCLs). To aid in combustion of the coal liquids, the ability to heat the fuel and inlet air was added. The MPCLs are derived from atmospheric distillation of coal liquids. The coal liquids are byproducts of coal gasification of Elkhorn bituminous and North Dakota lignite using the atmospheric, air blown Wellman-Galusha and pressurized, oxygen blown Lurgi gasifiers, respectively. The MPCLs were compared with three reference fuels: diesel No. 2, U12 (21 cetane number) and #-methyl napthalene (0 cetane number). The inlet air was heated from 340 to 535 K and the compression ratio was varied from 13 to 31 to provide sufficient range in temperature and pressure necessary for the combustion of low cetane number fuels. At each operating condition, fuel consumption, cylinder pressure, ignition delay, and emisions were measured.
1990-02-01
Technical Paper
900356
Keith Dewhirst, James Alexander McEwen, Kerry William Marsh, Mark Robert Firth
Engine development programs in general, and US exhaust emmisions legislation in particular have provided a challenge for turbomachinery suppliers, with requirements for higher boost pressures at low engine speeds and improved transient response. This must be achieved whilst maintaining or improving steady state aerodymnamic performance, reliability, durability and cost competitiveness. This paper discusses design issues, and describes some of the methods used, to create the first two models of a new range of turbochargers to meet the changing needs of automotive diesel engines in the 1990's.
1990-02-01
Technical Paper
900344
Harry C. Watson, Eric E. Milkins, Geoff R. Rigby
New concepts in oxygen enrichment of the inlet air have been examined in tests on two direct injection diesel engines, showing: significant reduction in particulate emissions (nearly 80% at full load), increased thermal efficiency if injection timing control is employed, substantial reductions in exhaust smoke under most conditions, ability to burn inferior quality fuels which is economically very attractive and achivement of turbo-charged levels of output with consequential benefits of increased power/mass and improved thermal efficiency. The replacement of an engine's turbocharger and intercooling system with a smaller turbocharger and polymeric membrane elements to supply the oxygen enriched stream should allow improved transient response. NOx emission remain a problem and can only be reduced to normally aspirated engine levels at some efficiency penalty.
1990-02-01
Technical Paper
900342
G. A. Eberhard, M. Ansari, S. K. Hoekman
A methanol-fueled transit bus with a 1988-technology Detroit Diesel Corporation (DDC) 6V-92TA engine was chassis dynamometer tested using steady-state and transient cycles to determine exhaust emissions and fuel economy. With chemical-grade methanol (M100), the bus had lower particulate, NOx, and heavy aldehyde emissions than the comparable (though older) diesel bus; however, formaldehyde and organic emissions were higher. Two other approaches were tried: methanol with 15% added gasoline (M85) and an exhaust catalyst (with M100). Both reduced formaldehyde and organic emissions relative to M100 alone, but they both increased heavy aldehyde emissions. The exhaust catalyst also reduced particulate emissions.
1990-02-01
Technical Paper
900329
Jerry Gallagher
Diesel particulate emissions are less than 2.5 micron. This size range particulate are major contributors to visibility-related problems in both urban and rural areas, as in the Denver Brown Cloud. Diesels are currently estimated to make up 10 to 20 percent of Denver's haze. Particulates in the diesel size range are also inhalable, capable of traveling deep into the lungs and being retained for long periods of time. As diesel particulates contain large quantities of organic materials, long term health effects from exposure to diesel particulates are of concern. It is estimated a diesel I/M Program will reduce diesel particulates from affected vehicles by 10 percent. Proposed changes would impact all diesel motorists and owners who have diesel motor vehicles registered or principally operated along Colorado's Front Range.
1989-09-01
Technical Paper
892130
Charles T. Flanigan, Thomas A. Litzinger, Ronald L. Graves
The effects of the chemical composition of Diesel fuels on emissions is a critical issue for future Diesel fuels and synthetic fuels. In order to understand these effects, a series of fuels prepared from blends of pure hydrocarbons were studied in a single cylinder, DI Diesel engine. The base fuel was a 2:1 mixture by volume of iso-octane and tetradecane with a Cetane number of 40.5. The additive compounds chosen for this study were 1-methylnaphthalene, tetralin, and decalin; each additive was blended into the base fuel at several concentrations so that the effect of the chemical compound on emission trends could be determined. To minimize changes in the combustion process, as fuel composition changed, the injection timing was varied in order to adjust for Cetane number differences between fuels. Comparisons were made on the basis of performance, regulated exhaust emissions, including CO, NOx UHC, and particulates, aldehyde emissions, and soluble organic fraction.
1989-09-01
Technical Paper
892132
John Henry Palumbo, Thomas A. Litzinger
The performance, combustion, and emissions of three coal-derived, test fuels were compared to a Phillips D-2 control fuel in a single cylinder, direct-injected, Diesel engine. The three synthetic test fuels were formed by varying the degree of hydrotreatment of a coal-liquid produced from the Exxon Donor Solvent (EDS) process; the three fuels have Cetane numbers of 29, 34.2, and 38.2. The objective of this research was to examine the effect of the degree of hydrotreatment on combustion, performance, and emission characteristics. The emissions measurements included both gas-phase emissions (CO, NOx, unburned hydrocarbons, and aldehydes), and particulate emissions. In addition, the Ames test was used to analyze the mutagenic activity of the soluble organic compounds found in the exhaust particulate.
1989-09-01
Technical Paper
892064
Charles M. Urban, Thomas J. Timbario, Richard L Bechtold
A study was conducted to determine the feasibility, performance, and emissions of a Detroit Diesel Corporation 8V-71 transit bus engine using ignition-improved methanol as fuel. Major objectives to be achieved by the study were: 1) to determine the minimum amount of ignition improver required for acceptable engine operation; and 2) to compare the exhaust emissions with ignition-improver methanol to emissions with diesel fuel. The engine was tested for emissions using the transient and 13-mode emission procedures and for smoke using the Federal smoke test. In addition to measurement of regulated emissions and smoke, cylinder pressure traces were obtained and compared with pressure traces from operation on diesel fuel. Minimum modifications were made to the engine in adapting it for operation on the methanol/additive mixture.
1989-09-01
Technical Paper
892072
Terry L. Ullman
Increasingly stringent emission requirements for heavy-duty diesel engines stresses the importance of both engine design and diesel fuel quality. The Coordinating Research Council sponsored this test work to yield quantitative emission data and emission models to relate diesel fuel properties to emissions from modern heavy-duty diesel engines. Regulated and selected unregulated emissions from three engines were measured over the EPA transient test procedure using several fuels having controlled variation in three primary fuel properties: aromatics, volatility (as the 90 percent boiling point temperature), and sulfur. Models for transient composite emissions were obtained using multiple linear regression techniques, and changes to regulated emissions for selected changes in fuel properties were estimated from the models. Of the three primary fuel variables, aromatic content and volatility were significant for emissions of HC, CO, and NOx.
1989-09-01
Technical Paper
892079
Montather K. Abbass, Gordon E. Andrews, Paul T. Williams, Keith D. Bartle
The objective was to investigate PAH emissions in diesel particulates using two diesel fuels with different PAH content. Class A2 diesel from two different refinery sources were analysed for PAH and there were significant difference in the concentration of the 3 and 4 ring PAH of importance in particulate PAH emissions. One fuel had at least 20 times the benzo[a]pyrene (BaP) of the other. A mass balance between the fuel PAH input to the engine and the particulate PAH emissions was carried out. A similar mass balance was also carried out between the equivalent boiling point n-alkane fuel and particulate SOF, which determined how that distillation fraction of the fuel behaved in the engine. One of the fuels had a higher survivability of high MW n-alkanes and this was also reflected in the PAH emissions. The fuel with high BaP had BaP emissions entirely consistent with an unburned fuel source.
1989-09-01
Technical Paper
892092
Lars Th Collin
The INCOLL or INertia COLLection system described in this paper, should meet the requirements for a short transient test, without using any chassis dynamometer. To prove this point not only the background of its principles are described, but also results from its application both to S I engines with and without catalytic converters and to truck diesel engines. Special interest has been devoted to the oxygen sensor and converter efficiency and their response both during warm up and under transient conditions. The simplification of the analyzing equipment and the direct interpretation of the results, have been dealt with, as well as the repeativity of the results achieved. The INCOLL test may also have a potential use as quality test at the end of the production line and as a tool for reliability development as well as research and development within the field. The cost for an INCOLL test is estimated to be around one (1) percent of a normal FTP certification procedure.
1989-09-01
Technical Paper
892046
K. Yoshida, S. Makino, S. Sumiya, G. Muramatsu, R. Helferich
Decreasing the level of NOx and particulate matter simultaneously from the exhaust of diesel engines has been demonstrated using newly developed catalyst compositions. Ignition temperatures below 400°C were observed in laboratory tests using catalyzed diesel particulate traps mounted to a single cylinder diesel engine connected to a dynamometer. This paper will report on the initial laboratory studies undertaken to evaluate the fundamental interaction between NOx and benzene derived particulate over customized catalytic materials. It will also address the role such particulates have on NOx reduction and discuss the effectiveness of decreasing NOx and particulates simultaneously on catalytically activated diesel particulate traps. Current and future work being performed on heavy duty truck engines incorporating these new catalyst compositions on a membrane-containing ceramic foam material is also addressed.
1990-04-01
Technical Paper
900883
David M. Human, Terry L. Ullman, Thomas M. Baines
Exhaust emissions from heavy-duty diesel engines operating at high altitude are of concern. EPA and Colorado Department of Health sponsored this project to characterize regulated and selected unregulated emissions from a naturally-aspirated Caterpillar 3208 and a turbocharged Cummins NTCC-350 diesel engine at both low altitude and simulated high attitude conditions (≈ 6000 ft). Emissions testing was performed over cold- and hot-start transient Heavy-Duty-Federal Test Procedure (HD-FTP) cycles as well as selected steady-state modes. In addition, the turbocharged engine was operated with mechanically variable and (fixed) retarded fuel injection timing to represent “normal” and “malfunction” conditions, respectively. High altitude operation generally reduced NOx emissions about 10 percent for both engines.
1990-02-01
Technical Paper
900854
J. R. Needham, M. P. May, D. M. Doyle, S. A. Faulkner, H. Ishiwata
This paper describes latest results from the Ricardo heavy duty diesel engine research programme. Using a Diesel Kiki P-TICS II injection system, matched to a low swirl combustion chamber, emission results well within the US 1991 engineering targets have been achieved with good fuel economy. Very low NOx levels have also been demonstrated whilst maintaining good fuel economy and particulate emissions within the 1991 standards. Analysis of results indicates that injection timing and rate control, as embodied in the P-TICS approach, is a key technology for achieving these low emissions with good fuel economy.
1990-02-01
Technical Paper
900821
David P. Sczomak
The “PCO” nozzle is a new design for direct injection diesels. It uses an outward opening poppet valve with orifices similar to those in hole-type nozzles. Hydrocarbons, NOx, light duty particulates and noise can be reduced. The orifices are completely covered when the valve is closed. No “sac” or orifice fuel can escape into the cylinder to increase hydrocarbons. The initial injection rate is reduced, lowering emissions and noise. With a near-vertical installation, the PCO can be substituted for hole-type nozzles and use the same combustion system. No fuel leakoff is required. Tests have been conducted in dynamometer engines and vehicles. Performance can be a trade-off, depending on the combustion system match. Remaining development work includes re-optimizing the combustion system for the PCO, enhancing the rate control capability, and demonstrating durability. Nozzle coking has been minimized with design and installation improvements but remains a concern.
1990-02-01
Technical Paper
900822
Horst Schulte, Manfred Duernholz, Kark Wuebbeke
Based on fundamental findings on mixture formation and combustion in Diesel engines, guidelines can be defined for further development of combustion systems with low exhaust and noise emissions. For the first combustion phase, these guidelines require the combustion of small fuel quantities to limit primary soot and NOx as well as combustion noise. In the second phase (Until end of injection) sufficient mixing of air and fuel is imperative to avoid formation of secondary soot and HC. In the third phase (after end of injection) intensive mixing of air and burned gases is necessary for the soot oxidation. The fuel injection system occupies a key position to fulfill, these requirements and, thereby, meet future demands with regard to exhaust and noise emissions. In this connection, results of experimental investigations with a single-cylinder four-valve engine have been analysed.
1990-02-01
Technical Paper
900814
VICTOR B. COOKE
Formulation changes in lubricating oils may be required to satisfy the needs of diesel engines meeting the exhaust emission limits scheduled for implementation in the United States during the 1990's. Compositional adjustments would be predicated on interactive engine/fuel/lubricant behavior. The dynamics of the interaction involve the mechanical engine design modifications necessary to achieve the standards, potential legislated limitations on fuel composition and the contribution of the lubricant itself to engine exhaust emissions, especially particulate emissions. An investigative program was undertaken using a 12.7 liter displacement Detroit Diesel Series 60 engine to explore these interactions. The effects of various speed/load/time/temperature cycles on engine deposits, wear, oil degradation, oil consumption and exhaust emissions are reported.
1990-02-01
Technical Paper
900112
Laslo Goldberger, Kong Ha, Jim Larocque, John Walsh, Andrew Skabowski
A diesel emission control system comprising two (2) catalyzed, monolithic ceramic exhaust filters, a diesel burner and electronic controller has been designed and installed on a 1982 GMC RTS-04 bus powered by a Detroit Diesel 6V-92TA engine. The system reduces exhaust particulates by over 80 percent and is also effective in reducing carbon monoxide and hydrocarbon emission. A minor NOx reduction was also observed. The New York City Transit Authority has operated the bus in downtown Manhattan since April, 1989. Its performance has been closely monitored and compared to a fleet of control buses running on the same route. Exhaust emission levels have been measured at regular intervals by NYCDEP to determine the emission reduction efficiencies and to track deterioration factors. Operating experience with this system is reported.
1990-02-01
Technical Paper
900110
Alex Lawson, Kong Ha, Ian Carmichael
Progress is reported on a project to evaluate the potential of diesel particulate trap systems for retrofit application to reduce emissions from buses and trucks in the State of California. A trap system was selected for evaluation, based on availability of commercial prototypes at the time of the project. Engine dynamometer testing of this trap system is reported over advanced design bus cycles. The results showed that the system is viable for application to a bus equipped with a Detroit Diesel Corporation 6V-92TA diesel engine, producing satisfactory exhaust backpressure and emission characteristics over a 500 hour test period. Work is now proceeding on field testing of this system on a transit coach, and engine dynamometer and field testing of a similar system on a truck equipped with a Cummins NTC 350 diesel engine.
1990-02-01
Technical Paper
900108
Marty A. Barris
Trap oxidizer systems for the filtration and oxidation of diesel exhaust particulate have been built and tested for a number of heavy-duty diesel applications. System design has been focused on electrically heated bypassed regeneration using wall flow monolith filters, and microprocessor based control for real time determination of particle mass on the trap. The durability of such systems has been demonstrated in the laboratory, in the engine test cell, and on vehicle applications. An accelerated durability test bench was developed for the purpose of assessing the system's (and especially the ceramic core's) ability to withstand a lifetime of thermal regeneration cycles. The results confirm previous projections regarding ceramic core life. A complete trap oxidizer system was manufactured and installed on a generator set test cell designed specifically to expose trap oxidizer systems to actual exhaust conditions for long term durability studies.
1990-02-01
Technical Paper
900107
Osamu Shinozaki, Eiichi Shinoyama, Keizo Saito
Exhaust particulates from diesel engines have become one of the most severe air pollution problems. The filter trap method is used to control diesel exhaust particulates. Hence, we have conducted an evaluation study of filter traps. In order to clarify the trapping performance such as filtration efficiency and pressure drops of the filter, four kinds of cordierite honeycomb type, two kinds of cordierite foam type and a mullite corrugation type filter were tested. For the honeycomb type filters, it is clear that the micro-pore size mainly affects the filtration efficiency and both the micro-pore size and the cell wall thickness mutually affect pressure drop. Furthermore, it was revealed that the pore size affects the filtration efficiency and pressure drop for the foam type filters. The Mullite corrugation type filter showed the highest filtration efficiency.
1989-09-01
Technical Paper
891972
Lawrence R. Smith, Jack Paskind
Two of the types of particulate trap systems that have evolved to control exhaust particulate matter include the catalyzed trap system and the additive-regenerated trap system. Exhaust emissions from these two types of trap systems have been characterized and quantified as completely as possible. The two vehicles evaluated in the study included a 1986 Mercedes-Benz 300 SDL, which utilizes a catalyzed trap system, and a prototype Volkswagen, which utilizes an additive trap system. The vehicles were tested using a chassis dynamometer, a dilution tunnel, and a constant volume sampler. The exhaust emissions were evaluated as to driving cycle, presence of particulate trap, engine condition, trap condition, and fuel aromatic content.
1990-02-01
Technical Paper
900693
Jan A. Gatowski
Abstract A single-cylinder direct-injection diesel engine with a displacement typical of passenger car practice was built to incorporate low-heat-rejection (LHR) components. These included a silicon-nitride piston cap, an Inconel firedeck, and stainless steel portliners, all backed by air gaps. In addition, a water-cooled engine with the same geometry was tested to provide a baseline. The LHR engine was tested with three different injector spray-tip geometries to assess the sensitivity of the results to the injection system. The LHR engine was worse than the baseline engine in most respects: it demonstrated higher fuel consumption and higher NO and HC emissions, and it rejected more heat at a given operating condition. The exhaust smoke emissions from both engines were similar, with the LHR engine having a small advantage at 2000 r/min. Destructive failure of the piston cap occurred after roughly 60 hours of operation.
1990-02-01
Technical Paper
900641
Teluan Chen, Chkvar Anatoli, Anhe Wei, Yibi Weng
Experimental investigation on a high speed single-cylinder diesel engine has shown that a gas-pressure stabilizer in the exhaust system has obvious effect upon engine performance. Two types of such gas pressure stabilizers were tested, and a reduction of about 0.5% to 2% in fuel consumption rate was achieved, which was mainly dependent on the type of stabilizer employed and was more significant under higher speed conditions.
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