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Viewing 61 to 90 of 190956
2010-09-28
Technical Paper
2010-32-0020
Paul Ravenhill, Jeffrey Allen, Benajmin Smither, Gavin Farmer, Eric Demesse, Philippe Grosch
The ideal attributes of light weight, low cost and high power density have made the 2-stroke engine unrivalled in the scooter and moped market for many years. However, the challenges of meeting new emissions regulations, especially the latest Euro III emission test cycle have reduced the 2-stroke's dominance and it is now often considered to be too dirty and inefficient to have a future. As a result its product placement is on the decline. This paper introduces and discusses the latest application of a low-cost high-frequency injection system (Pulse Count Injection [ 1 , 2 ]) to both the fuel flow and lubrication oil flow of a 2-stroke scooter; allowing both fluids to be individually mapped and optimised for the complete engine operating range. This in turn enables the 2-stroke engine to pass the latest Euro III test whilst improving the fuel economy by a considerable margin, without changing the architecture of the engine.
2010-09-28
Technical Paper
2010-32-0019
Roland Oswald, Andreas Ebner, Roland Kirchberger
The Institute of Internal Combustion Engines and Thermodynamics at Graz University of Technology has developed a low-pressure (5 bar) direct injection (LPDI) combustion system for 50 cm₃ two-stroke engines during the last years. The 50 cm₃ two-stroke engine is a specific European engine class. Worldwide the 125 cm₃ class is more important. In order to investigate the potential of higher displacement engines equipped with the LPDI combustion process, a demonstrator engine with 250 cm₃ has been developed. The results of this demonstrator from the engine test bench and from the chassis dynamometer are discussed to show the potential of this two-stroke technology. In order to ease the interpretation, the results of a homogenously scavenged two-stroke engine and of a naturally aspirated four-stroke engine serve as reference. The results show that the LPDI technology is a real alternative to expensive four-stroke engines.
2010-09-28
Technical Paper
2010-32-0018
Lei Tian
Miniature size internal combustion (IC) engines with displacements in the neighborhood of 1 cc have the potential to function as high power and energy density miniature power supplies. The engines, which are currently used in model airplanes, have higher power and longer run times than a battery coupled to an electric motor. The Center for Compact and Efficient Fluid Power (CCEFP), a seven university research consortium in the United States, is developing miniature IC engines for applications in human size mobile devices such as robots and medical assistive devices, aiming at more compact design and longer operation time. To advance the development of new compact power supplies, it is necessary to understand the performance characteristics of current miniature engines. As the scale of an engine gets smaller, surface effects such as friction, heat loss, and leakage get more significant [ 1 ].
2010-09-28
Technical Paper
2010-32-0017
Oliver Schoegl, Stephan Schmidt, Martin Abart, Christian Zinner, Roland Kirchberger, Mathias Fitl, Karl Glinsner, Stefan Leiber
The development process of 2-stroke engines is characterized by limited CFD investigations in combination with long-term development phases on the test bench with high prototype costs. To reduce the costs and to realize shorter development time together with a higher prediction quality of the engine potential, a higher implementation level of 1D and 3D simulation tools into the development process is necessary. This publication outlines the 1D simulation methods in the layout phase of GDI combustion processes of 2-stroke engine categories. By means of conceptual investigations, the demands, the potential and the limits of 1D CFD simulation methodology are defined. Using a comparison between 1D and 3D or 1D/3D coupled simulation methods the limits of solely 1D simulation are shown. For advanced simulation tasks with a higher demand for prediction quality, the entire engine is simulated in 1D, whereas special parts of the engine design are simulated in a 3D model.
2010-09-28
Journal Article
2010-32-0016
Giovanni Ferrara, Alessandro Bellissima, Marco Doveri, Francesco Balduzzi
The purpose of this work is to perform an analysis on the modifications necessary to convert a four-stroke engine into a non-conventional two-stroke engine. The first aim of this work is to reach the theoretical advantages of the two stroke engine (high torque values at lower rpm and working regularity) and, at the same time, to avoid the usual problems of the two stroke cycle (short-circuit of fresh air-fuel mixture and consequently pollutant emissions and high specific fuel consumption). The target is to develop a small engine with innovative solutions that allows to obtain high performance coupled with good mechanical and thermodynamic efficiency. The starting base engine is a 125cc four-stroke two-valves scooter engine equipped with a volumetric compressor. The idea is to convert it from four to two stroke cycle, using head valves and adding scavenge ports in the cylinder.
2010-09-28
Technical Paper
2010-32-0014
Dalibor Jajcevic, Raimund Almbauer, Stephan Schmidt, Karl Glinsner, Matthias Fitl
The advantages of 2-stroke engines, high power and low weight, are in conflict with their disadvantages, high emissions and bad fuel economy. As these disadvantages are caused by the scavenging process, a reason for the problem can be analyzed by using three dimensional computational fluid dynamics simulation (3D CFD simulation). The scavenging losses can be dramatically reduced with a high pressure fuel injection strategy. The purpose of this strategy is to prevent a fuel concentration in the incoming charge and to reduce the fuel concentration inside the exhaust system. These advantages can only be successfully exploited with the application of an optimal injection strategy. This paper covers a spray study for a gasoline direct injection (GDI) high performance 2-stroke engine using the commercial CFD Code Fluent.
2010-09-28
Journal Article
2010-32-0015
Dalibor Jajcevic, Raimund Almbauer, Stephan Schmidt, Karl Glinsner, Matthias Fitl
CFD has been widely used to predict the flow behavior inside 2-stroke engines over the past twenty years. Usually a mass flow profile or a simple 0D model is used for the inlet boundary condition, which replaces the complete intake geometry, such as reed valve, throttle, and air box geometries. For a CFD simulation which takes into account the exact reed valve geometry, a simulation of all above mentioned domains is required, as these domains are coupled together and thus interact. As the high speed of the engine affects the opening dynamic and closure of the reed valve, the transient data from the crank case volume and the section upstream the reed valve have an important influence on the reed petal dynamic and therewith on the sucked fresh air mass of the engine. This paper covers a methodology for the transient CFD simulation of the reed petals of a 2-stroke engine by using a 2D model.
2010-09-28
Technical Paper
2010-32-0013
Christian Gruenzweig
Dynamic neutron radiography is a non-destructive inspection method. It provides different attenuation contrast compared, e.g., to common X-ray imaging. This allows neutrons to penetrate centimeter thick layers of metals while fuel or lubricants can still deliver good visibility. With beam cross sections between 3 cm and 30 cm (squared), neutron radiography is an ideal tool for the visualization of running combustion engines. Here we report on an experiment that demonstrates the feasibility to visualize a fired two-stroke chain saw engine running at idle speed (~ 3000 rpm). A sequence of single frames of the running engine was recorded and combined into a movie which provides a view into the moving parts of the engine, the combustion chamber and the crank case.
2010-09-28
Technical Paper
2010-32-0046
P. Shanmugam, T. Kathiresan, N. Senthilnathan, AS. Anbukarasu, R. Vinoth Balaram, K. Prabu, MG. Naveenkumar
Pollutants are harmful to human and other living beings on the earth. Thus emission reduction plays a very important role in the survival of living beings. Hydrocarbons (HC), Carbon monoxide (CO), Nitrogen oxides (NOx) are the emission constituents which results in smog, respiratory problems in human beings, acid rain respectively. Hence, Indian government has taken necessary steps to reduce these emissions and imposed various level of norms like BSI, BSII and BSIII on 2/3 wheeler industries in the year 2000, 2005 and 2010 respectively. Presently in India, BSII is in force and from October 2010 BSIII will be introduced. BSIII 3 wheeler norm, the CO emission level is reduced by 44.4% and HC+NOx is reduced by 37.5%. The main objective of this work is to reduce the emissions like HC, which is due to unburnt fuels, NOx, which is due to high engine pressures and temperatures and CO, which is a byproduct of incomplete combustion.
2010-09-28
Technical Paper
2010-32-0047
Tim Hands, Alexander John Finch, Jonathan Symonds, Chris Nickolaus
This paper describes various aspects of the particle emissions from a 2-stroke motorbike. It gives an indication of issues which may face emissions engineers if (or when) such vehicles become subject to particulate legislation similar to that for light duty vehicles. A DMS500 fast particulate spectrometer was used to examine transient particle emissions from the CVS tunnel for two 2-stroke motorbikes over the European ECE R47 and urban New European Drive Cycle (NEDC) drive cycles. One was direct injected and the other was carburretted. Transient size spectra and number data from the output of a two stage, Particulate Measurement Program (PMP) compliant heated dilution system are presented for the carburretted 2-stroke motorbike running the urban phase of the NEDC. Estimates of the particle number emissions relative to the Euro 5b light-duty diesel vehicle legislation are presented.
2010-09-28
Technical Paper
2010-32-0042
Scott A. Miers, Christopher A. Green, Jay S. Meldrum, Christine Lundberg, William Silvis, Harry Pankratz
Recent increases in emissions regulations within the snowmobile industry have led to significant advancements in fuel, exhaust, and control systems on snowmobiles. However, particulate matter is currently an unregulated exhaust component of snowmobile engines. The measurement of dry soot as well as particulate matter from snowmobiles is the focus of this paper. Two industry-representative snowmobiles were chosen for this research which included a 2006 Yamaha Nytro carbureted four-stroke and a 2009 Ski-Doo MX-Z direct-injected two-stroke. Measurements for each snowmobile included gaseous emissions (CO₂, CO, NOx, O₂, and THC), particulate matter collected on quartz filters, and dry soot measured using an AVL Micro Soot Sensor. Each snowmobile was tested over the industry-standard five-mode emissions certification test cycle to determine the emissions, dry soot, and particulate matter levels from idle to wide open throttle (full-load).
2010-09-28
Journal Article
2010-32-0044
Katsumasa Kiuchi, Ryo Suzuki, Hiroaki Yano, Shintaro Yagi, Akihiko Tomoda
We investigated the catalytic performance of a porous-structured paper coated with precious metals such as palladium (Pd) and others. A honeycomb-shaped paper catalyst was successfully produced by paper making techniques, which are often used in the friction material manufacturing process for clutch system and the following newly developed molding process. As a new catalyst on the paper, Pd supported on Mn-substituted lanthanum hexa-aluminate (LaMnAl₁₁O₁₉, magnetoplumbite, MPB) crystallites with appropriate surface area was prepared and the catalytic performance, such as exhaust purification ability, was assessed using a model gas containing HC (hydrocarbon), CO (carbon monoxide) and NO (nitrogen oxide) gas. The results showed that Pd/MPB did not deteriorate even after 180 h aging at 1000°C. We concluded that the MPB has good potential as a catalyst component material for internal combustion engines because of the high thermal stability.
2010-09-28
Technical Paper
2010-32-0040
Jing Qin, Manqun Lin, Liang Zhao, Bin Jia, Peng Liu
Gasoline-fueled small engines have been developed predominantly for power by using fuel-rich combustion, and unburned HC is usually a consequence of inadequate mixing and combustion of the charge. In principle, a straightforward way to reduce HC emissions is to run at an almost stoichiometric air-fuel ratio while NOx emission become problematic, namely a tradeoff exists between the amount of HC and NOx emission, especially at high engine loads. Cooled exhaust gas recirculation (EGR) is a common way to control in-cylinder NOx production when burning stoichiometric or even leaner mixture. In this paper, experimental investigations were conducted on a small off-road gasoline engine to study the effect of EGR system on the engine-out emission especially the unburned HC and NOx.
2010-09-28
Technical Paper
2010-32-0041
Jih Houh Lee, Horizon Gitano, Hock Seng Eu, Ahmad Syazli Mohd Khalil
Existing drive cycles do not correlate well with actual drive cycles in developing countries due to differences in vehicle mixes, and traffic flow patterns. Several distinct drive cycles were identified in Malaysia namely the urban, suburban, rural, highway and delivery drive cycles. Several methods were used in generating drive cycles including direct observation, motorcyclist surveys, vehicle shadowing with on-board wheel speed measurement and data logging. These drive cycles were compared to existing European, United States, world harmonized motorcycle drive cycles and evaluated for fuel consumption. Results indicate that the Malaysian drive cycles are capable predicting actual vehicle fuel mileage within +/− 10% for a wide range of vehicles, while the European drive cycle results in a 20%deviation from the actual vehicle fuel mileage.
2010-09-28
Technical Paper
2010-32-0038
Jordan Szafranski, Mike Galligan
Exhaust catalyst deactivation in small, handheld, 2-stroke engines is an issue that is faced quite frequently in efforts to improve or maintain catalyst performance but reduce cost. Fresh catalyst performance is rarely an issue, however, sustaining this performance for the specified useful life period of 50, 125, or 300 hours is where challenges start to arise. Our program goal was to develop and demonstrate a commercially viable catalyst which is capable of meeting regulatory and internal requirements with a deterioration factor (DF) near or below 1.0 over a 300 hour useful life period. A secondary objective was to utilize decreased quantities of platinum group metals (PGM) to reduce the cost relative to our reference catalyst. To achieve this, our focus was to reduce poisoning caused by exhaust byproducts and exhaust borne contaminants through a collaboration of catalyst advances and exhaust system design.
2010-09-28
Technical Paper
2010-32-0039
Manqun Lin
Some motorcycles, such as 3 wheels and scooters, have dual high exhaust characteristics on CO and NOx. A mechanical exhaust gas recirculation (EGR in brief) system has been developed for motorcycles and attempt to reduce NOx exhaust emission as a valuable method. Mechanical control valve are driven by intake vacuum of the engine. Appropriate amount of exhaust gas are return to engine intake system during acceleration process and high speed condition. This system also can shut down EGR at deceleration and idling speed condition. Then, NOx and fuel consumption reduction performance was confirmed by means of experimental methods.
2010-09-28
Technical Paper
2010-32-0036
Christoph Dutzler, Gregor Heizinger, Andreas Mair
The continuously increasing product complexity on the one side, and the demand to constantly decrease development times and costs on the other, require new development processes in the automotive industry. This paper describes a product development process which, by intensively and systematically applying computer-aided modeling techniques, makes a significant contribution to the management of this tremendous complexity in a cost- and time- efficient manner. The presented process strives for a widespread usage of modeling techniques (such as physical system modeling and simulation, model-based control system design, rapid prototyping, etc.) over all technical domains involved in the product (mechanics, hydraulics, electrics, electronics, software, etc.) as well as over several stages of the product development process.
2010-09-28
Technical Paper
2010-32-0037
Reza Rezaei, Stefan Pischinger, Jens Ewald, Philipp Adomeit
The fulfillment of the aggravated demands on future small-size High-Speed Direct Injection (HSDI) Diesel engines requires next to the optimization of the injection system and the combustion chamber also the generation of an optimal in-cylinder swirl charge motion. To evaluate different port concepts for modern HSDI Diesel engines, usually quantities as the in-cylinder swirl ratio and the flow coefficient are determined, which are measured on a steady-state flow test bench. It has been shown that different valve lift strategies nominally lead to similar swirl levels. However, significant differences in combustion behavior and engine-out emissions give rise to the assumption that local differences in the in-cylinder flow structure caused by different valve lift strategies have noticeable impact. In this study an additional criterion, the homogeneity of the swirl flow, is introduced and a new approach for a quantitative assessment of swirl flow pattern is presented.
2010-09-28
Technical Paper
2010-32-0034
Michael Steinbatz
The formation of a hydrodynamic lubrication is the essential condition for any friction bearings in combustion engines for optimum performance. The shaft and the bearing are separated by a thin sustainable lubrication film, which prevents a direct metal to metal contact. The resulting fluid friction allows for a low frictional loss and the prevention of wear under normal operating conditions. The hydrodynamic load capacity of the bearings is a result of an oil flow, caused by the rotating shaft and/or bearing within the viscous medium. Depending on the gap geometry (shaft eccentricity) a hydrodynamic pressure is built up in the lubrication film. This pressure separates the surfaces that define the lubrication film and thus equilibrates the external bearing load. However, the local pressure inside the lubrication film will cause local deformations of the shaft and bearing, which again will affect the pressure build-up due to a change of the gap geometry.
2010-09-28
Technical Paper
2010-32-0035
Dalibor Jajcevic, Matthias Fitl, Stephan Schmidt, Karl Glinsner, Raimund Almbauer
The exhaust system design has an important influence on the charge mass and the composition of the charge inside the cylinder, due to its gas dynamic behavior. Therefore the exhaust system determines the characteristics of the indicated mean effective pressure as well. The knowledge of the heat transfer and the post-combustion process of fuel losses inside the exhaust system are important for the thermodynamic analysis of the working process. However, the simulation of the heat transfer over the exhaust pipe wall is time consuming, due to the demand for a transient simulation of many revolutions until a cyclic steady condition is reached. Therefore, the exhaust pipe wall temperature is set to constant in the conventional CFD simulation of 2-stroke engines. This paper covers the discussion of a simulation strategy for the exhaust system of a 2-cylinder 2-stroke engine until cyclic steady condition including the heat transfer over the exhaust pipe wall.
2010-09-28
Technical Paper
2010-32-0032
Claudio Annicchiarico, Renzo Capitani, Riccardo Testi
The paper is focused on the stress field acting on a continuously variable transmission (CVT) mechanism used on the high displacement scooters produced by Piaggio & C. S.p.A. The most important results of the analysis have been extrapolated with the aim of providing the designers with some guidelines useful to reduce the design error occurrence. In detail, in the paper is described the behavior of the belt and of the driven pulley, that are the critical parts of the assembly. The analysis has been conducted with a full MultiBody model of the mechanism combined with the Finite Element analysis of both the belt and the pulley. The output data so obtained have been used in a fatigue analysis in order to define the reliability of these parts. This paper could serve as a base to define a new proportioning method, that should be based on the whole stress history of each part of the assembly, computed with the aid of some numerical tools.
2010-09-28
Technical Paper
2010-32-0033
Om Singh, T. Sreenivasulu, M Kannan, K. Nagaraja
The air-cooled engine surfaces are generally provided with extended surfaces of high conducting materials called fins for enhanced heat transfer. One way to increase the rate of heat transfer is by increasing the fins surface area. However, increase in fin length introduces undesirable vibrations of the fins, which in turn radiate annoying high frequency noise. With the demand of quieter engines increasing, the vehicle manufacturers follow counter measures to minimize the fin vibrations. One trend in the two-wheeler industry is to put rubber dampers between the fins. These rubber dampers damps out the level of vibrations and the level of noise radiated is reduced. However, these rubber dampers have many disadvantages. Apart from the adding extra cost and a parallel manufacture process, these rubbers act as an insulating material, which impede the free flow of cooling air. The engine may get overheated and purpose of providing extended surface would not be satisfied.
2010-09-28
Technical Paper
2010-32-0030
Martin Abart, Stephan Schmidt, Oliver Schoegl, Alexander Trattner, Roland Kirchberger, Helmut Eichlseder, Dalibor Jajcevic
This publication covers investigations on different 3D CFD models for the description of the spray wall and droplet-fluid interaction and the influence of these models on the mixture formation calculation results. Basic experimental investigations in a spray chamber and a flow tunnel as well as the corresponding 3D CFD simulation were conducted in order to clarify the prediction quality of the physical phenomena of spray-wall and spray-fluid interaction by the simulation. Influencing parameters such as the piston top temperature, piston bowl geometry, soot deposits on the piston top as well as flow velocity are investigated. This paper provides a direct link between the underlying simulation models of the mixture formation and actual real world combustion system development processes - underlining the importance of a close interaction of the model calibration and the development process.
2010-09-28
Technical Paper
2010-32-0031
Kenji Nishio
In this paper, the development of a multiaxial fatigue failure criterion is shown, and as an application of the above criterion, a fatigue analysis of a crankcase is conducted. The octahedral shear stress amplitude and the peak value of the maximum principal stress are used in this criterion. The accuracy of the criterion is validated by tension-torsion biaxial fatigue tests. Furthermore, fatigue failure prediction of a crankcase is carried out using static analysis and the criterion. The combination of the static analysis and the criterion enable the prediction of fatigue failure.
2010-09-28
Technical Paper
2010-32-0066
Toshifumi Uehara, Kouji Miyake, Yoshikazu Tanaka, Yukitaka Tsuda
There is a growing demand for ethanol fuel for which attention is being paid as an alternative fuel for petroleum from the standpoint of CO2 reduction and fuel economy. Especially in Brazil under the government policy of bio-fuel promotion, the regular gasoline containing 20% of alcohol and 100% alcohol are being sold, requiring a system that can cope with a high-alcohol-content fuel mixing the aforementioned fuels. As the dusts in the fuel disperse in the form of fine particles because the high-alcohol-content fuel has a high affinity, the amount of dust that passes through the fuel filter increases. At the same time, there was such a concern that the pump case, which was composed of the pump cover and the pump housing, wore and reduced fuel flow as the amount of dust that entered the fuel feed pump (hereafter referred to as FFP) increased.
2010-09-28
Journal Article
2010-32-0064
Yasuo Moriyoshi, Minoru Iida
In a motorcycle gasoline engine, the port fuel injection system is rapidly spread. Compared to an automotive engine, the injected fuel does not impinge on the intake valve due to space restriction to install the injector. In addition, as the air flow inside the intake pipe may become very fast and has large cycle-to-cycle variation, it is not well found how the injector should be installed in the intake pipe to prepare “good” fuel-air mixture inside the intake pipe. In this study, the formation process of the fuel-air mixture is measured by using ILIDS system that is a 2-D droplets' size and velocity measurement system with high spatial resolution. Experiments with changing conditions such as flow speed and injection direction are carried out.
2010-09-28
Technical Paper
2010-32-0068
Shaiju M. Belsus, Gopi Sankar, Amol Sharma
Reliability has been a complicated domain of vehicle engineering, basically due to the quantum of the authentic data required, and variability of parameters that make real contributions to the subject. Reliability of a vehicle in very generic terms, is not only its functional worthiness and consistency, but also its probability to perform satisfactorily within the intended design life for a particular production batch, application domain, operation duty and customer use. Commercial vehicle industry is driven by returns that a vehicle gives, on the investments made, which depend on parameters like minimum turnaround time, lesser breakdowns, optimized maintenance interval and cost of operation etc. Severe operating conditions, regular customer abuse and higher expectations from products (as expected by Indian customer-base) demand a need to deliver more robust and reliable products.
2010-09-28
Technical Paper
2010-32-0067
Anand T. N. C., Madan Mohan Avulapati, Devendra Deshmukh, Ravikrishna Rayavarapu
In the present study, PFI injectors which are suitable for small engines were characterized to study the effect of pressure on various spray parameters. Two plate-type PFI injectors were studied: one with two orifices, and the other with four orifices. The nozzle orifice sizes were determined by microscopy. The fuel quantity injected at pressures of 200 kPa, 500 kPa and 800 kPa, were measured by collecting the fuel, for injection pulses of different durations. The spray structure of the PFI sprays was determined by shadowgraphy. A single pulsed Nd:YAG laser in conjunction with fluorescent diffuser optics was used as the light source for shadowgraphy. Backlit images of the spray were obtained at various times after the start of injection using a CCD camera. This was done for sprays at different pressures, and different pulse durations. The spray angle, and spray tip penetration were determined from the processed shadowgraphy images.
2010-09-28
Technical Paper
2010-32-0060
Rainer Aufischer
Environmental regulations all over the globe and the demand on fuel efficient engines have increased bearing loads dramatically over the last 20 years, especially in small and high speed Diesel engines. Lead containing Bronze bearings, often with a Lead based overlay have become a standard in the automotive industry and are used over decades. Due to the harmful and poisonous effect of lead on the environment the European Union has set up the Vehicle end-of-life Regulation to reduce use of lead, also in tribological products. In order to fulfill the high load capability and the necessary tribological behavior of engine bearings new approaches in fatigue, temperature stability and Tribology has to be taken. Basic investigation of the tribological working principles in bearings combining short term failure mechanism and long term behavior were carried out to understand the interaction of materials, layers and lubrication.
2010-09-28
Technical Paper
2010-32-0059
Silvio Barbarelli, Sergio Bova, Rocco Piccione
Variable-displacement lubricating pumps are an attractive solution for reducing fuel consumption and emissions in motorcycle engines. In this prospective, modeling and experimental analysis are very useful means for a deeper understanding of pump operation and for effectively implementing pump control. Zero-dimensional simulation results of a 7-vane pump were compared with the experimental data of dynamic piezo-resistive pressure transducers fitted into the casing of a pump prototype, which was operated under steady-state conditions at different rotational speeds and eccentricity values. The experimental data exhibit oscillations which were explained by taking into account the pressure transducers dynamics, as a result of the transducer location in the pump casing, of the air dissolved in the hydraulic fluid and of the geometry of the tubing/transducer system.
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