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Technical Paper

Optimization of Engine System for Application of Biodiesel Fuel

2007-07-23
2007-01-2028
Application of biodiesel fuel (BDF) to diesel engine is very effective to reduce CO2 emission, because biodiesel is carbon neutral in principle. However, biodiesels yield an increase in NOx emission from conventional diesel engine, compared with diesel fuel case. Therefore, some strategies are needed for meeting the future emission regulations when using biodiesel. In this study, rapeseed oil methyl ester (RME) was applied to diesel engine equipped with exhaust gas recirculation (EGR) system and NOx storage reduction (NSR) catalyst. NOx reduction rate of NSR catalyst was drastically decreased by using RME, even if injection quantity of RME for rich spike was enhanced. However, an increase in EGR rate could reduce NOx emission without the deterioration in smoke and PM emissions.
Technical Paper

PM Measurement with Partial Dilution Tunnel - Influence of Sampling Line on PM Measurement -

2001-09-24
2001-01-3580
The full-flow dilution tunnel (hereinafter referred to as full tunnel) measurement method has become the de facto standard for the evaluation of particulate matter (hereinafter referred to as PM) emitted from diesel-powered vehicles. However, due to its drawbacks such as bulkiness and expensiveness, a method that uses a very small partial dilution tunnel (hereinafter referred to as micro tunnel) has been developed, mainly in Europe, nearly to the level of practicality. With this method, a higher degree of freedom in controlling sampling flow and temperature can be obtained. Another advantage of the micro tunnel is that the system is compact. However, the micro tunnel's measurement accuracy remains uncertain because the accumulation of measurement data is not yet sufficient. Measuring PM while varying micro tunnel operating parameters permitted a check on the equivalency with a full tunnel system.
Technical Paper

A New Type Partial Flow Dilution Tunnel with Geometrical Partitioning for Diesel Particulate Measurement

2001-09-24
2001-01-3579
The authors have developed a new partial flow dilution tunnel (hereafter referred to as PPFT), whose principal device is a flux splitting gas divider, as a new means of measuring particulate emissions which can be applied to transient cycle testing of diesel engines. The advantage of this system is that it can achieve perfect constant velocity splitting by means of its structure, and theoretically can also maintain high splitting performance despite fluctuations in the exhaust flow rate, including those due to engine exhaust pulsation. We compared this system with a full tunnel by analyzing the basic performance of the system and measuring particulate matter (PM) using an actual vehicle engine.
Technical Paper

Effect of Exhaust Gas Recirculation on Exhaust Emissions from Diesel Engines Fuelled with Biodiesel

2007-09-16
2007-24-0128
Application of biodiesel fuel (BDF) to diesel engine is very effective to reduce CO2 emission, because bio-diesel is carbon neutral in principle. However, when biodiesel was applied to conventional diesel engines without modification for biodiesel, NOx emission was increased by the change in fuel characteristics. It is necessary to introduce some strategies into diesel engines fuelled with biodiesel for lower NOx emission than conventional diesel fuel case. The purpose of this study is to reveal that exhaust gas recirculation (EGR) is one of the solutions for the reduction of NOx emission and meeting the future emission regulations when using biodiesel. Neat Rapeseed oil methyl ester (RME) as a biodiesel (B100) was applied to diesel engines equipped with high pressure loop (HPL) EGR system and low pressure loop (LPL) EGR system. Cooled HPL EGR was increased during steady-state operations and JE05 transient mode tests.
Technical Paper

Study of the Effect of Boiling Point on Combustion and PM Emissions in a Compression Ignition Engine Using Two-Component n-Paraffin Fuels

2002-03-04
2002-01-0871
Fuel composition is investigated as a parameter influencing fuel/air mixing of direct injected fuel and the subsequent consequences for particulate emissions. Presumably, enhanced mixing prior to ignition results in a larger portion of fuel burning as a premixture and a smaller portion of diffusion burning around fuel-rich regions. This would potentially lower particulate emissions without overly compromising hydrocarbon emissions or high load operation. Using mixtures of n-paraffin fuels, particulate emissions were measured and the results were compared with in-cylinder visualization of the injection process and two-color method calculations of flame temperature. In general, lower boiling point fuels exhibited higher flame temperatures, less visible flame, and lower particulate emissions.
Technical Paper

An Experimental Study on Phenomena of Piston Ring Collapse

2002-03-04
2002-01-0483
This study has been conducted aiming at an experimental verification of the ring collapse phenomena that occurs in a taper faced second ring of a direct fuel injection type truck diesel engine. The oil film thickness of the second ring, the ring axial motion and the inter-ring pressure have been measured under various operating conditions of engine. As a result, it is verified that the back pressure of the second ring becomes lower than the second land pressure, and that the second ring oil film becomes extremely thick temporarily where the second ring contacts with the ring groove upper surface. It is also verified that blow-by passes through the second ring where the oil film of the second ring becomes thick. Hence it is highly probable that the collapse of the second ring has occurred at that time.
Technical Paper

Combustion Characteristics of H2-CO-CO2 Mixture in an IC Engine

2001-03-05
2001-01-0252
Reformed fuel from hydrocarbons or alcohol mainly consists of hydrogen, carbon monoxide and carbon dioxide. The composition of the reformed fuel can be varied to some extent with a combination of a thermal decomposition reaction and a water gas shift reaction. Methanol is known to decompose at a relatively low temperature. An application of the methanol reforming system to an internal combustion engine enables an exhaust heat recovery to increase the heating value of the reformed fuel. This research analyzed characteristics of combustion, exhaust emissions and cooling loss in an internal combustion engine fueled with several composition of model gases for methanol reformed fuels which consist of hydrogen, carbon monoxide and carbon dioxide. Experiments were made with both a bottom view type optical access single cylinder research engine and a constant volume combustion chamber.
Technical Paper

Improvement of Combustion and Exhaust Gas Emissions in a Passenger Car Diesel Engine by Modification of Combustion Chamber Design

2006-10-16
2006-01-3435
Three types of combustion chamber configurations (Types A, B, and C) with compression ratio lower than that of the baseline were tested for improved performance and exhaust gas emissions from an inline-four-cylinder 1.7-liter common-rail diesel engine manufactured for use with passenger cars. First, three combustion chambers were examined numerically using CFD code. Second, engine tests were conducted by using Type B combustion chamber, which is expected to have the best performance and exhaust gas emissions of all. As a result, 80% of NOx emissions at both low and medium loads at 1500 rpm, the engine speed used frequently in the actual city driving, improved with nearly no degradation in smoke emissions and brake thermal efficiency. It was shown that a large amount of cooled EGR enables NOx-free combustion with long ignition delay.
Technical Paper

Control Strategy for Urea-SCR System in Single Step Load Transition

2006-10-16
2006-01-3308
Urea-SCR system has a high NOx reduction potential in the steady-state diesel engine operation. In complicated transient operations, however, there are certain problems with the urea-SCR system in that NOx reduction performance degrades and adsorbed NH3 would be emitted. Here, optimum urea injection methods and exhaust bypass control to overcome these problems are studied. This exhaust bypass control enables NO/NOx ratio at the inlet of SCR catalyst to be decreased widely, which prevents over production of NO2 at the pre-oxidation catalyst. Steady-state and simple transient engine tests were conducted to clarify NOx reduction characteristics when optimum urea injection pattern and exhaust bypass control were applied. In simple transient test, only the engine load was rapidly changed for obtaining the fundamental knowledge concerning the effect of those techniques.
Technical Paper

Evaluation of Regulated Materials and Ultra Fine Particle Emission from Trial Production of Heavy-Duty CNG Engine

2006-10-16
2006-01-3397
A prototype CNG engine for heavy-duty trucks has been developed. The engine had sufficient output in practical use, and the green-house gas emission rate was below that of the base diesel engine. Furthermore, the NOx emission rate was reduced to 0.16 g/kWh in the JE05 mode as results of having fully adjusted air fuel ratio control. The measured emission characteristics of particles from the prototype CNG engine demonstrated that oil consumption was related to the number of particles. Moreover, when oil consumption is at an appropriate level, the accumulation mode particles are significantly reduced, and the nuclei mode particles are fewer than those of diesel-fueled engines.
Technical Paper

Influence of Diesel Post Injection Timing on HC Emissions and Catalytic Oxidation Performance

2006-10-16
2006-01-3442
For diesel emission control systems containing a Diesel Oxidation Catalyst (DOC) and a Catalyzed Soot Filter (CSF) the DOC is used to oxidize the additional fuel injected into the cylinder and/or the exhaust pipe for the purpose of increasing the CSF inlet temperature during the soot regeneration. Hydrocarbon (HC) oxidation performance of the DOC is affected by HC species as well as a catalyst design, i.e., precious metal species, support materials and additives. How engine-out HC species vary as a function of fuel supply conditions is not well understood. In addition, the relationship between catalyst design and oxidation activity of different hydrocarbon species requires further study. In this study, diesel fuel was supplied by in-cylinder, post injection and exhaust HC species were measured by a gas chromatograph-mass spectrometry (GC-MS) and a gas analyzer. The post injection timing was set to either 73°, 88° or 98° ATDC(after top dead center).
Technical Paper

Development of DME Engine for Heavy-duty Truck

2006-04-03
2006-01-0052
In recent years, attention has focused on smokeless, sulfur-free dimethyl ethyl (DME) as a clean fuel for heavy-duty diesel vehicles [1]. In this development, the DME engine applied for 20-ton GVW truck was developed under the auspices of the Ministry of Land, Infrastructure and Transport of Japan, the first known instance worldwide. With careful design of the fuel system considering DME's unique fuel characteristics and suitable combustion improvement, higher torque was obtained with DME, compared to diesel fueling. and also use of the proper EGR and catalyst, exhaust emissions levels were generally less than one-fourth of new long-term regulation value promulgated in 2005 Japan.
Technical Paper

Application of Biodiesel Fuel to Modern Diesel Engine

2006-04-03
2006-01-0233
The 1997 Kyoto protocol came into effect in February, 2005 to reduce greenhouse gases within the period 2008-2012 by at least 5 % with respect to 1990 levels. Application of biodiesel fuel (BDF) to diesel engine is very effective to reduce CO2 emission, because BDF is carbon neutral in principle. The purpose of this project is to produce a light-duty biodiesel truck which can be suitable for emission regulation in next generation. The effect of BDF on the performance and emissions of modern diesel engine which was equipped with the aftertreatment for PM and NOx emissions was investigated without modifications of engine components and parameters, as a first step for research and development of biodiesel engine. Rapeseed oil methyl ester (RME) was selected in behalf of BDF, and combustion characteristics, engine performance and exhaust emissions were made a comparison between RME and petroleum diesel fuel by steady operation and Japan transient mode (JE05) tests.
Technical Paper

Achievement of Medium Engine Speed and Load Premixed Diesel Combustion with Variable Valve Timing

2006-04-03
2006-01-0203
A variable valve timing (VVT) mechanism was applied to achieve premixed diesel combustion at higher load for low emissions and high thermal efficiency in a light duty diesel engine. By means of late intake valve closing (LIVC), compressed gas temperatures near the top dead center are lowered, thereby preventing too early ignition and increasing ignition delay to enhance fuel-air mixing. The variability of effective compression ratio has significant potential for ignition timing control of conventional diesel fuel mixtures. At the same time, the expansion ratio is kept constant to ensure thermal efficiency. Combining the control of LIVC, EGR, supercharging systems and high-pressure fuel injection equipment can simultaneously reduce NOx and smoke. The NOx and smoke suppression mechanism in the premixed diesel combustion was analyzed using the 3D-CFD code combined with detailed chemistry.
Technical Paper

Trapping Performance of Fine Particles from a Diesel Engine by Various DPFs with Different Surface Structures

2004-03-08
2004-01-0598
The regulation of particulate matter (PM) from diesel engines is coming to be very stringent at present. The usage of diesel particulate filter (DPF) is now under consideration in many heavy-duty diesel vehicle manufacturers to reduce PM emission from a diesel engine. The possibility that very fine particles may pass through DPF is suggested. The understanding of fine particles emission behaviors and the countermeasure of reducing particle emissions from DPF will come to be important in near future. The behavior of particle size distribution after DPF has not been studied enough yet. In this study, fine particles generated by a diesel engine are introduced to honeycomb type and SiC (Silicon Carbite) fiber type DPFs and the collection performances of fine particles by various DPFs with different surface structures have been examined.
Technical Paper

Influence of Dilution Process on Engine Exhaust Nano-Particles

2004-03-08
2004-01-0963
Recently, particulate matter (PM) emission from internal combustion engines, especially particles having the diameter of less than 100 nm (Nano-particles) are being considered for their potential hazards posed to human health and the environment. Nano-particles are unstable and easily influenced by the conditions of engine operation and measurement techniques. In this study, the influences of cooling and dilution processes on nano- particles are presented to understand the generation and dilution mechanisms, and to further development of an accurate measurement method. It is found that the thermo-dilurter is necessary for measuring the nano-particles with higher accuracy. Accurate measurement of nano-particles requires immediate dilution of the exhaust gases by hot air.
Technical Paper

Comparative Measurement of Nano-Particulates in Diesel Engine Exhaust Gas by Laser-Induced Incandescence (LII) and Scanning Mobility Particle Sizer (SMPS)

2004-06-08
2004-01-1982
Particulate Matter (PM) from diesel engines is thought to be seriously hazardous for human health. Generally, it is said that the hazard depends on the total number and surface area of particles rather than total mass of PM. In the conventional gravimetric method, only the total mass of PM is measured. Therefore, it is very important to measure not only the mass of PM but also size and number density of particulates. Laser-Induced Incandescence (LII) is a useful diagnostic for transient measurement of soot particulate volume fraction and primary particle size. On the other hand, Scanning Mobility Particle Sizer (SMPS) is also used to measure the size distribution of soot aggregate particulates at a steady state condition. However, the measurement processes and the phenomena used to acquire the information on soot particulate are quite different between the LII and SMPS methods. Therefore, it is necessary to understand the detailed characteristics of both LII and SMPS.
Technical Paper

Real-Time Measurement of Particle Size Distribution From Diesel Engines Equipped With Continuous Regenerative DPF Under a Transient Driving Condition

2004-06-08
2004-01-1984
A new PM measurement method, such as particle measurement equipments, samplings and so on, is being studied at present for a type approval test in the future. Particles emitted from diesel engines, especially the particles that are called “Nuclei Mode Particles” are very unstable and easily influenced by the engine operating conditions and the measurement conditions. Most of nuclei mode particles are said to consist of volatile organic particles with mainly high carbon numbers. It is said that a continuous regenerative type DPF (Diesel Particulate Filter) consisting of oxidation catalyst and ceramic filter will prevail in the near future. These particles may be able to be reduced by an oxidation catalyst in this DPF.
Technical Paper

Effects of Fuel Properties on Combustion and Exhaust Emissions of Homogeneous Charge Compression Ignition (HCCI) Engine

2004-06-08
2004-01-1966
Homogeneous Charge Compression Ignition (HCCI) is effective for the simultaneous reduction of soot and NOx emissions from diesel engine. In general, high octane number and volatility fuels (gasoline components or gaseous fuels) are used for HCCI operation, because very lean mixture must be formed during ignition delay of the fuel. However, it is necessary to improve fuel injection systems, when these fuels are used in diesel engine. The purpose of the present study is the achievement of HCCI combustion in DI diesel engine without the large-scale improvements of engine components. Various high octane number fuels are mixed with diesel fuel as a base fuel, and the mixed fuels are directly applied to DI diesel engine. At first, the cylinder pressure and heat release rate of each mixed fuel are analyzed. The ignition delay of HCCI operation decreases with an increase in the operation load, although that of conventional diesel operation does not almost varied.
Technical Paper

Diesel Emissions Improvement by RME in a High Boost and EGR Single Cylinder Engine

2008-04-14
2008-01-1376
The biomass fuel is expected to solve the global warming due to a carbon neutral. A rapeseed oil methyl ester (RME) as biomass fuel was selected, and also a low sulfur diesel fuel is tested as reference fuel in this study. The experiments were carried out to improve diesel emissions and engine performance using high boost and high rate EGR system and a common rail injection system in a single cylinder engine. The diesel emissions and engine performance have been measured under the experimental conditions such as charging boost pressure from atmospheric pressure to 401.3kPa maximum and changing EGR rate from 0% to 40% maximum. RME contain about 10 mass % oxygen in the fuel molecule. Furthermore, RME does not contain aromatic hydrocarbons in the fuel. Due to these chemical properties, RME can be used at 40% high EGR condition.
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