Criteria

Text:
Content:
Display:

Results

Viewing 1 to 30 of 39992
2015-01-01
Technical Paper
2014-01-9053
Tobias Breuninger, Jürgen Schmidt, Helmut Tschoeke, Martin Hese, Andreas Kufferath, Frank Altenschmidt
The spray-guided combustion process offers a high potential for fuel savings in gasoline engines in the part load range. In this connection, the injector and spark plug are arranged in close proximity to one another, as a result of which mixture formation is primarily shaped by the dynamics of the fuel spray. The mixture formation time is very short, so that at the time of ignition the velocity of flow is high and the fuel is still largely present in liquid form. The quality of mixture formation thus constitutes a key aspect of reliable ignition. In this article, the spray characteristics of an outward-opening piezo injector are examined using optical testing methods under pressure chamber conditions and the results obtained are correlated with ignition behaviour in-engine. The global spray formation is examined using high-speed visualisation methods, particularly with regard to cyclical fluctuations. In order to characterise the recirculation zone of the hollow cone spray that is relevant to the ignition behaviour, laser-optical measuring methods were used.
2014-11-11
Technical Paper
2014-32-0071
Christian Schweikert, David Witt, Dirk Schweitzer, Marco Nicolo, Liu Chen
Abstract The market potential for products such as scooters and small motorcycles is already self-sustaining. However, other applications for small engines can be more fragmented with a wide variety of requirements for the engine control unit. Consequently, the engine control unit can be designed to accommodate more features than are necessary for a given application to cover a broader market. The flip side of this approach is to design the engine control unit for a limited application reducing the market size. Neither approach creates a cost efficient product for the producer. It either supplies the market with an electronic control unit that has features not being utilized (wasted costs) or a unit that has limited capabilities reducing the economies of scale (higher costs). When these designs are developed using discrete components these inefficiencies are exacerbated. Integration of these functions at the semiconductor level can mitigate these costs, improve the thermal performance and expand the functional capabilities to include additional vehicular control aspects in the electronic control unit.
2014-11-11
Technical Paper
2014-32-0084
Eiji Kinoshita, Akira Itakura, Takeshi Otaka, Kenta Koide, Yasufumi Yoshimoto, Thet Myo
Abstract In order to improve the cold flow properties of coconut oil biodiesel and to reduce the lifecycle CO2 emission by using bio-alcohol at biodiesel manufacturing, varying the types of alcohol used at transesterification was examined. The pour point of coconut oil ester decreases as the carbon number of alcohol increases. Among 5 ester fuels, the pour point of coconut oil isobutyl ester (CiBE) made from isobutanol is lowest, −12.5 °C, compared to that of coconut oil methyl ester (CME), highest, −5 °C. The pour point of coconut oil 1-butyl ester (CBE) is −10 °C, second lowest. Furthermore, CBE, CiBE, CME and JIS No.2 diesel fuel (gas oil) were tested using a DI diesel engine. CBE and CiBE have shorter ignition delay compared to the gas oil although slightly longer than CME. CBE and CiBE have the same thermal efficiency and NOx emissions compared to the gas oil. HC, CO and Smoke emissions of coconut oil ester fuels slightly increase when the ester molecule carbon number increases. However, these exhaust emissions are lower than that of the gas oil.
2014-11-11
Technical Paper
2014-32-0086
Yasufumi Yoshimoto, Eiji Kinoshita, Kazuyo Fushimi, Masayuki Yamada
Abstract This paper describes the influence of different kinds of FAME (fatty acid methyl ester) on the smoke emissions of a small single cylinder DI diesel engine and the soot formation characteristics in suspended single droplet combustion. The study used eight kinds of commercial FAME and diesel fuel blends. The tested FAMEs are saturated fatty acids with 8 to 18 carbon molecule chains, and with three different double bonds with C18. The results show that with all the FAME mixtures here, the brake thermal efficiencies with the FAME-diesel fuel blends were similar to neat diesel fuel operation while the smoke emissions with all of the tested FAME-diesel fuel blends were lower. To examine the differences in the soot formation characteristics, measurements of the formed soot mass were also performed with a basic experimental technique with suspended single droplet combustion. The soot was trapped on a glass fiber filter, and the mass of the filter was measured with an electronic microbalance.
2014-11-11
Technical Paper
2014-32-0090
Jeffrey Blair, Glenn Bower
Abstract Operation of snowmobiles in national parks is restricted to vehicles meeting the Best Available Technology standard for exhaust and noise emissions as established by the National Parks Service. An engine exceeding these standards while operating on a blend of gasoline and bio-isobutanol has been developed based on a production four-stroke snowmobile engine. Miller cycle operation was achieved via late intake valve closing and turbocharging. The production Rotax ACE 600cc 2 cylinder engine was modeled using Ricardo WAVE. After this model was validated with physical testing, different valve lift profiles were evaluated for brake specific fuel consumption and brake power. The results from this analysis were used to determine a camshaft profile for Miller cycle operation. This was done to reduce part load pumping losses and increase engine efficiency while maintaining production power density. A catalytic converter was added to reduce exhaust gas emissions, as measured by the EPA 40 CFR Part 1051 5-mode emissions test cycle.
2014-11-11
Technical Paper
2014-32-0004
Yuma Ishizawa, Munehiro Matsuishi, Yasuhide Abe, Go Emori, Akira Iijima, Hideo Shoji, Kazuhito Misawa, Hiraku Kojima, Kenjiro Nakama
Abstract One issue of Homogeneous Charge Compression Ignition (HCCI) engines that should be addressed is to suppress rapid combustion in the high-load region. Supercharging the intake air so as to form a leaner mixture is one way of moderating HCCI combustion. However, the specific effect of supercharging on moderating HCCI combustion and the mechanism involved are not fully understood yet. Therefore, experiments were conducted in this study that were designed to moderate rapid combustion in a test HCCI engine by supercharging the air inducted into the cylinder. The engine was operated under high-load levels in a supercharged state in order to make clear the effect of supercharging on expanding the stable operating region in the high-load range. HCCI combustion was investigated under these conditions by making in-cylinder spectroscopic measurements and by analyzing the exhaust gas using Fourier transform infrared (FT-IR) spectroscopy. The results revealed that cool flame reactions were induced by increasing boost pressure when gasoline with a Research Octane Number of approximately 91 was used as the test fuel.
2014-11-11
Technical Paper
2014-32-0093
Francesco Catapano, Silvana Di Iorio, Paolo Sementa, Bianca Maria Vaglieco, Marcello Fiaccavento, Francesco Giari, Antonio Marchetti
Abstract This paper investigates abnormal combustion during the cranking phase of spark-ignition small engines, specifically the occurrence of backfire at the release of the starter motor during kickback. The research focusses on the influence of fuel composition, mainly in terms of ethanol percentage, on backfire occurrence. Interest in this abnormal combustion is growing due to the increased use of fuels with different chemical-physical properties with respect to gasoline. Moreover, this issue will become even more topical due to the implementation of simple control and fuel supply systems on low cost-engines, which are widely used in developing countries. Experimentation was carried out in an optically accessible engine derived from a 4-stroke spark ignition engine for two-wheel vehicles. The test bench was instrumented and adapted in order to simulate the engine conditions that lead to anomalous ignition in the intake duct (backfire) during the reverse rotation of the engine (kickback).
2014-11-11
Technical Paper
2014-32-0102
Patrick Pertl, Philipp Zojer, Michael Lang, Oliver Schoegl, Alexander Trattner, Stephan Schmidt, Roland Kirchberger, Nagesh Mavinahally, Vinayaka Mavinahalli
Abstract The automotive industry has made great efforts in reducing fuel consumption. The efficiency of modern spark ignition (SI) engines has been increased by improving the combustion process and reducing engine losses such as friction, gas exchange and wall heat losses. Nevertheless, further efficiency improvement is indispensable for the reduction of CO2 emissions and the smart usage of available energy. In the previous years the Atkinson Cycle, realized over the crank train and/or valve train, is attracting considerable interest of several OEMs due to the high theoretical efficiency potential. In this publication a crank train-based Atkinson cycle engine is investigated. The researched engine, a 4-stroke 2 cylinder V-engine, basically consists of a special crank train linkage system and a novel Mono-Shaft valve train concept. The idea of a Mono-Shaft valve train mechanism is to realize the valve actuation without the need for separate cam shafts and gears, but via a cam disk rotating with crankshaft speed, thus enabling the integration of the cam disk in the crankshaft.
2014-11-11
Technical Paper
2014-32-0100
Ken Naitoh, Takuma Okamoto, Tomoaki Kubota, Kan Yamagishi, Yoshiyuki Nojima, Taro Tamura
An inexpensive, lightweight, and relatively quiet engine reactor that has the potential to achieve thermal efficiency over 50% for small engines was proposed in our previous reports, which is achieved with colliding supermulti-jets that create air insulation to encase burned gas around the chamber center, avoiding contact with the chamber walls and piston surfaces. The colliding of pulse jets can maintain high pressure ratio for various air-fuel ratios, whereas traditional homogeneous compression engines due to piston cannot get high pressure ratio at stoichiometric condition. Emphasis is also placed on the fact that higher compression in this engine results in less combustion noise because of encasing effect. Here, a small prototype engine having supermulti-jets colliding with pulse and strongly-asymmetric double-piston system is examined by using computational experiments. Pulse can be generated by the double piston system of a short stroke of about 40mm. Computations at some loads and engine speeds show a potential of high thermal efficiency over 60%, because there is very less heat loss on combustion chamber and piston surface.
2014-11-11
Technical Paper
2014-32-0005
Keisuke Mochizuki, Takahiro Shima, Hirotaka Suzuki, Yoshihiro Ishikawa, Akira Iijima, Koji Yoshida, Hideo Shoji
Abstract Homogeneous Charge Compression Ignition (HCCI) has attracted a great deal of interest as a combustion system for internal combustion engines because it achieves high efficiency and clean exhaust emissions. However, HCCI combustion has several issues that remain to be solved. For example, it is difficult to control engine operation because there is no physical means of inducing ignition. Another issue is the rapid rate of heat release because ignition of the mixture occurs simultaneously at multiple places in the cylinder. The results of previous investigations have shown that the use of a blended fuel of DME and propane was observed that the overall combustion process was delayed, with that combustion became steep when injected propane much. This study focused on expanding the region of stable engine operation and improving thermal efficiency by using supercharging and blended fuels. The purpose of using supercharging were in order to moderated combustion. In addition, the purpose of using blended gaseous fuels were find out effective use of gaseous fuels.
2014-11-11
Technical Paper
2014-32-0002
Yudai Yamasaki, Shigehiko Kaneko
Abstract To determine the auto-ignition and combustion mechanisms and the components of syngas that are applicable to homogeneous charge compression ignition (HCCI) engines, the combustion characteristics and the chemical reaction process in an HCCI engine were studied numerically and experimentally using mock syngas with various mixtures of the fuel components. The mock syngas consisted of hydrogen (H2) and carbon monoxide (CO) as the main combustible components, nitrogen (N2) and carbon dioxide (CO2) as incombustible components and a small amount of methane (CH4), assuming the composition of the gas was produced from wood by thermochemical conversion processes. The oxidation reaction process was analyzed numerically using CHEMKIN-PRO. Further experiments were conducted to investigate the validity of the calculated results. Primarily, the effects of hydrogen and carbon monoxide on auto-ignition and combustion were investigated. Auto-ignition timing mainly depends on the in-cylinder gas temperature and the auto-ignition temperature is approximately 1100 K, which is the same as that of hydrocarbon fuels.
2014-11-11
Technical Paper
2014-32-0007
Joseph K. Ausserer, Alexander K. Rowton, Keith D. Grinstead, Paul J. Litke, Marc D. Polanka
Abstract In this work, in-cylinder pressure was measured in a 55 cc single cylinder, 4.4 kW, two stroke, spark ignition engine. In cylinder pressure measurements were taken using two different pressure transducers to determine if the performance differences between the two transducers are discernible in a small, spark ignition engine. A Kistler brand measuring spark plug was compared to a Kistler brand flush mount high temperature pressure sensor. Both sensors employ piezo-electric pressure sensing elements and were designed to measure indicated mean effective pressure as well as to detect knock at high temperature engine conditions. The pressure sensors were installed and adjusted to ensure cylinder volume after sensor installation matched the engine's original configuration within reasonable manufacturing tolerances. A series of tests at four throttle settings ensued to determine if either device altered the combustion volume or the engine's performance. Performance measurements were obtained over a range of engine speeds from 4000 rpm to 6000 rpm.
2014-11-11
Technical Paper
2014-32-0006
Federico Brusiani, Gian Marco Bianchi, Cristian Catellani, Marco Ferrari, Paolo Verziagi, Dario Catanese
Abstract Still today, two-stroke engine layout is characterized by a wide share on the market thanks to its simpler construction that allows to reduce production and maintenance costs respecting the four-stroke engine. Two of the main application areas for the two-stroke engines are on small motorbikes and on handheld machines like chainsaws, brush cutters, and blowers. In both these application areas, two-stroke engines are generally equipped by a carburettor to provide the air/fuel mixture formation while the engine cooling is assured by forcing an air stream all around the engine head and cylinder surfaces. Focusing the attention on the two-stroke air-cooling system, it is not easy to assure its effectiveness all around the cylinder surface because the air flow easily separates from the cylinder walls producing local hot-spots on the cylinder itself. This problem can be bounded only by the optimization of the cylinder fin design placed externally to the cylinder surface. In the present paper the authors present a first analysis of the thermal-flow behaviour of a two stroke engine designed for brush-cutter machine applications.
2014-11-11
Technical Paper
2014-32-0008
Stefan Krimplstätter, Franz Winkler, Roland Oswald, Roland Kirchberger
Abstract The Institute for Internal Combustion Engines and Thermodynamics, Graz University of Technology, has presented several applications of its 2-stroke LPDI (low pressure direct injection) technology in the previous years ([1], [2], [3]). In order to improve the competitiveness of the 2-stroke LPDI technology, an air cooled 50cm3 scooter application has been developed. All previous applications have been liquid cooled. This air cooled application demonstrates the EURO 4 (2017) ability of the technology and shows that the 2S-LPDI technology can also be applied to low cost air-cooled engines. Hence, the complete scooter and moped fleet can be equipped with this technology in order to fulfil both the emission standards and the COP (conformity of production) requirements of Euro 4 emission stage. The paper presents the Euro 4 Scooter results and describes the efficient conversion process of the existing carburetor engine to the LPDI version. Euro 4 results can be achieved with conventional exhaust system architecture known from the present Euro 2 applications.
2014-11-11
Technical Paper
2014-32-0010
Alexander K. Rowton, Joseph K. Ausserer, Keith D. Grinstead, Paul J. Litke, Marc D. Polanka
Abstract As IC engines decrease in displacement, their cylinder surface area to swept volume ratio increases. Examining power output of IC engines with respect to cylinder surface area to swept volume ratio shows that there is a change in power scaling trends at approximately 1.5 cm−1. At this size, it is suggested that heat transfer from the cylinder becomes the dominant thermal loss mechanism and performance and efficiency characteristics suffer. Furthermore, small IC engines (>1 cm−1) have limited technical performance data compared to IC engines in larger size classes. Therefore, it is critical to establish accurate performance figures for a family of geometrically similar engines in the size class of approximately 1.5 cm−1 in order to better understand the thermal losses that contribute to lower efficiencies in small IC engines. The engines considered in this scaling study were manufactured by 3W Modellmotoren, GmbH. In particular, they are the 3W-28i, 3W-55i, and 3W-85Xi engines, which have cylinder surface area to swept volume ratios of 1.83 cm−1, 1.46 cm−1, and 1.27 cm−1 respectively.
2014-11-11
Technical Paper
2014-32-0111
Brian Mason, Keith Lawes
Abstract For handheld power tools, a four-stroke engine allows compliance with exhaust emissions regulations although four-stroke engines available tend to have unfavorable power to weight. The requirement for a low cost diecast block compromises valve sizes and port flow. While dynamic valve train limitations restrict maximum engine speeds. The use of a rotary valve as opposed to poppet valves avoids these issues and results in an engine with competitive performance. The engine block can be diecast and the engine can operate up to 14,000 rpm without valve related issues. This paper describes the evolution of a rotary valve concept and its application to two 35cc handheld development engines. The HRCV35 is based on a belt driven rotary valve horizontally mounted parallel to the crankshaft axis. The VRCV35 is based on a gear driven rotary valve vertically mounted on the cylinder axis. In both configurations, the rotary valve exposes inlet and exhaust ports providing unrestricted flow. The valve generates turbulence for easy starting and can operate on low volatility fuels such as aviation kerosene or JP8.
2014-11-11
Technical Paper
2014-32-0001
Naoya Ito, Akira Iijima, Akira Terashima, Junki Sahara, Takashi Shimada, Masanori Yamada, Tomohiko Asai, Mitsuaki Tanabe, Koji Yoshida, Hideo Shoji
Abstract This study investigated the effect of streamer discharge on autoignition and combustion in a Homogeneous Charge Compression Ignition (HCCI) engine. A continuous streamer discharge was generated in the center of the combustion chamber of a 2-stroke optically accessible engine that allowed visualization of the entire bore area. The experimental results showed that the flame was initiated and grew from the vicinity of the electrode under the application of a streamer discharge. Subsequently, rapid autoignition (HCCI combustion) occurred in the unburned mixture in the end zone, thus indicating that HCCI combustion was accomplished assisted by the streamer discharge. In other word, ignition timing of HCCI combustion was advanced after the streamer discharging process, and the initiation behavior of the combustion flame was made clear under that condition.
2014-11-11
Technical Paper
2014-32-0040
John Walters, Francois Brun
Abstract Stringent emissions legislation is being applied to small motorcycles and scooters around the world. This is forcing, gradually, the replacement of carburetors by electronic fuel injection (EFI) systems. The integration of this new technology creates new constraints on the engine and also on the vehicle. This study will provide an overview of these constraints and also technical solutions to reduce the impact on engine and vehicle. A special focus will be done on the fuel system, where the development of an advanced technology will be discussed in detail. This technology marks a break with the standard automotive fuel system architecture in order to fulfill the specific requirements of scooters and small motorcycles: low size, low weight, low energy demand, as well as simple integration. The discussion will disclose: the advantages and drawbacks of different fuel system architectures, the detailed description of the technology selected to achieve the requirements, the modelling approach used for the sizing and optimization of the design, and finally the performance achieved on the test bench.
2014-11-11
Technical Paper
2014-32-0055
Francesco Maiani, Alessio Sisi, Walther Leardini
Abstract In recent years the 2-wheelers engines companies have been focused on increasing the overall engine efficiency, that can be achieved amongst other by engine down-speeding, engine down-sizing and by reducing the frictions; however, to maintain or improve vehicle performance, it is necessary to provide a corresponding increase in specific power. In accordance with these trends, the studied approaches and methodologies have been exploited, during the development of the new Piaggio small scooter engine. In this work a multi-objective analysis has been applied to the valve train system design, in order to optimize the engine performance in terms of friction reduction, power curve and timing system response. Along with this optimization methodology, a robust design has been studied to make the peak cranking compression pressure insensitive to the engine starting device working. These calculation methodologies have been followed using commercial software as GT-SUITE® code and the modeFRONTIER® platform for the multi-objective optimization analysis.
2014-11-11
Technical Paper
2014-32-0064
Koorosh Khanjani, Jiamei Deng, Andrzej Ordys
Abstract Increasing the efficiency and durability of internal combustion engines is one of the major concerns of engineers in the development of modern road vehicles. Emission legislations are becoming intensively strict each year, forcing manufacturers to deploy sophisticated engine control strategies. The engine coolant temperature is conventionally controlled with mechanical elements such as wax-thermostat and belt-driven mechanical water-pump, which result in engine temperature fluctuations and delayed response to variable inputs. Variable coolant temperature is beneficial; it can decrease the hydrodynamic frictional losses of lubricated engine parts in light duty conditions. Moreover it improves performance and protects engine parts from thermal stresses and sealing failure in heavy duty conditions. In this paper the feasibility of controlling coolant temperature is examined in different driver demand conditions using electric flow-control valve replacing conventional thermostat. Urban, extra urban and highway cycles are tested on Honda insight 2003 (without the electric motor) from Advisor software vehicle simulator.
2014-11-11
Technical Paper
2014-32-0061
Rama Subbu, Baskar Anthony Samy, Piyush Mani Sharma, Prasanna Mahendiran
Abstract Ride comfort, driving stability and drivability are vital factors in terms of vehicle performance and customer satisfaction. Crankshaft unbalance is a source for the vibration that reduces the vehicle performance and it needs to be controlled to some extent such that the vehicle performance will be improved. The IC engine is made up of reciprocating and rotating parts. They produce unbalance forces during their operation and produces vibration in Vehicle. The vibration reduction will be possible by minimizing these unbalance forces and by optimizing the crankshaft of the two wheeled vehicle engine design. Many researches were made to find the causes for the vibration and to reduce it. But still there is a research gap on the testing and simulation of engine components (crankshaft, connecting rod and piston assembly). In this study, an attempt is made to represent the engine vibrations and its isolation to provide a gate way for the future work on it. This study shows the various steps carried out on the multibody modeling of the IC engine components including engine crankshaft and their orientations.
2014-11-11
Technical Paper
2014-32-0069
Ken Fosaaen
Abstract Global concerns over pollution have led to increasingly strict emissions legislation targeting small engines, which currently pollute at a much greater level than modern multi-cylinder automotive engines. Closed-loop control may be required to meet many future legislation requirements; however, such systems can be impractical due to high added component costs. A necessary component for closed-loop engine control is an oxygen sensor. Existing automotive oxygen sensors are too large, require too much power, and are far too expensive to be suitable for the vast majority of the global small engine applications; therefore, some manufacturers have developed smaller and/or unheated versions based on their existing sensors to meet this emerging need. The ability to miniaturize resistive based sensors well below that of traditional Nernst (zirconia based) oxygen sensors affords the opportunity to meet future emissions standards with less of an impact on cost. The performance of a novel low-cost, low-power, narrow-band resistive-based oxygen sensor was compared with the stock oxygen sensor and several other commercially available oxygen sensors on a 2014 Honda Grom 125E motorcycle.
2014-11-11
Technical Paper
2014-32-0068
Klaus Stuhlmüller, Denis Lenz, Sebastian Hook, Dirk Hohenhaus, Michael Schwarz
Abstract In each operating state and operating environment, optimum ignition is ensured by continuously analyzing sensor values. Engine manufacturers continue to be faced with the challenge of ensuring that the machine runs as smoothly and quietly as possible. Increased spark duration and higher energy of the ignition spark enable improved combustion of the gasoline-air mixture in the combustion compartment. This article describes an electrical ignition process using an array of multiple coils and a magnetic generator that is rotating in sync with the machine. During this process the magnetic field temporarily flows through the coils and generates a sequence of magnetic flow variations per rotation. This induces corresponding half-waves of alternating voltage in the coils of the ignition module. This article describes a way to use these half-waves for prolonging the ignition spark, leading to a booster effect. Specifically, the text describes the method depicted under patent US 6701896 B2, comparing different ignition modules with and without booster effect (Ref. 1).
2014-11-11
Technical Paper
2014-32-0105
Atsushi Maruyama, Gaku Naoe
Abstract For a small general purpose engine, the authors have studied on “combustion noise”, the mechanical noise originating from combustion. The purpose of this study is to clarify the mechanisms of combustion noise generation. The engine used in this study was a 4-stroke air-cooled single-cylinder engine with the typical characteristics of 3.5 kW-class small general purpose engines, which was specifically designed for experiments. We analyzed the operational behaviors of parts such as the crankshaft, the flywheel and the crankcase during the time of occurrence of combustion noise. Results of the analysis showed that the primary component of combustion noise in small general purpose engines is radiated from the flywheel connected to the crankshaft, and that the vibration mode that radiates the noise is excited by bending deformation of the crankshaft under explosion load. Based on these results, this paper will also discuss the effect of the stiffness of the main bearings on combustion noise.
2014-11-11
Technical Paper
2014-32-0104
Alexander Shkolnik, Daniele Littera, Mark Nickerson, Nikolay Shkolnik, Kukwon Cho
Abstract This paper describes the development of small rotary internal combustion engines developed to operate on the High Efficiency Hybrid Cycle (HEHC). The cycle, which combines high compression ratio (CR), constant-volume (isochoric) combustion, and overexpansion, has a theoretical efficiency of 75% using air-standard assumptions and first-law analysis. This innovative rotary engine architecture shows a potential indicated efficiency of 60% and brake efficiency of >50%. As this engine does not have poppet valves and the gas is fully expanded before the exhaust stroke starts, the engine has potential to be quiet. Similar to the Wankel rotary engine, the ‘X’ engine has only two primary moving parts - a shaft and rotor, resulting in compact size and offering low-vibration operation. Unlike the Wankel, however, the X engine is uniquely configured to adopt the HEHC cycle and its associated efficiency and low-noise benefits. The result is an engine which is compact, lightweight, low-vibration, quiet, and fuel-efficient.
2014-11-11
Technical Paper
2014-32-0113
Vipin Sukumaran T., Sumith Joseph, Kamal kant, Vipin P, Mohan D Umate
Abstract In recent past, the two stroke vehicle manufacturers are continuously motivated to develop extreme low emission vehicle for meeting the requirements of emissions regulations. To achieve this emission compliance, manufacturers have developed engines with better induction system, improved ignition timings, increased compression ratio (C.R) and larger after-treatment devices. As an effect of above changes, engine operating temperatures are quite high which reduces the block-piston life. Even though, typical two stroke engines are forced cooled engines, there is a lot of potential for optimizing block cooling to reduce maximum liner temperature and block gradient for enhancing block-piston durability. This paper presents an experimental study of various measures to reduce liner temperature for a two stroke, single cylinder 70 c.c. engine used for two wheeler application. By studying the cooling air flow around the block and block to interface parts heat transfer, the following parts were redesigned to reduce maximum liner temperature - exhaust gasket, base gasket, cooling fan profile and cooling cowl.
2014-11-11
Technical Paper
2014-32-0128
Francisco Payri, José Javier Lopez, Benjamin Pla, Diana Graciano Bustamante
Abstract Direct injection compression ignited (CI) engines are today's most efficient engine technology, granting efficiencies exceeding 40% for their optimal operation point. In addition, a strong technological development has allowed the CI engine to overcome its traditional weak points: both its pollutant emissions and the gap in specific power regarding its competitor, i.e. the spark ignited (SI) engine, have been noticeably reduced. Particularly, the increase in specific power has led to the downsizing as an effective method to improve vehicle efficiency. Despite the reduction in total displacement, the cylinder displacement of current CI engines is still around 0.5 liters. For some applications (urban light duty vehicles, Range Extenders…) it may be interesting to reduce the engine displacement to address power targets around 20kW with high efficiencies. This paper assesses the thermo- and fluid-dynamic limitations which make challenging extending the application of automotive CI engines to the low power region: Firstly, space limitations for injection and combustion processes.
2014-11-11
Technical Paper
2014-32-0130
Takashi Onishi, Tomoya Akitomo, Yuichi Tamaki, Yoshikazu Takemoto, Hideyuki Goto, Mitsugu Okuda
Abstract All of non-road diesel engines over 19 kW in North America are required to reduce further Nitrogen Oxides (NOx) and Particulate Matter (PM) to meet US EPA emissions regulation. Especially, it is necessary to reduce PM emission up to one-tenth as conventional. In addition to improve combustion in engine, it is needed to add exhaust gas after-treatment device to reduce PM emission. It is necessary for diesel engine with exhaust gas after-treatment device, to have Diesel Particulate Filter (DPF) regeneration system, which burns periodically PM in DPF. Generally, DPF regeneration is implemented by using post injection with common rail system. However, post injection is not available in small diesel engine which has mechanical injection system and IDI combustion system instead of common rail system. As an alternative way, an original fuel reformer technique is introduced for DPF regeneration. Fuel reformer is located in the upper exhaust gas flow of DPF, and works independently from fuel injection system of engine.
2014-11-11
Technical Paper
2014-32-0136
Thomas Metzinger, Christoph Raber, Christoph Wittmann
Abstract This paper discusses the design elements for a wet clutch system to successfully meet the requirements of today's motorcycle market. You can find new design ideas regarding how to realize important and critical clutch performance features such as torque boost, coast torque reduction (anti-hopping function), reduced actuation force, reduced drag torque, optimized weight, and/or optimized product cost. Most of these functions and features can be implemented in a modular clutch kit in which many of the parameters can be adapted with a minor design change of just a few components.
2014-11-11
Technical Paper
2014-32-0109
Denis Neher, Maurice Kettner, Fino Scholl, Markus Klaissle, Danny Schwarz, Blanca Gimenez
Abstract Electrical power and efficiency are decisive factors to minimise payoff time of cogeneration units and thus increase their profitability. In the case of (small-scale) cogeneration engines, low-NOx operation and high engine efficiency are frequently achieved through lean burn operation. Whereas higher diluted mixture enables future emission standards to be met, it reduces engine power. It further leads to poor combustion phasing, reducing engine efficiency. In this work, an engine concept that improves the trade-off between engine efficiency, NOx emissions and engine power, was investigated numerically. It combines individual measures such as lean burn operation, overexpanded cycle as well as a power- and efficiency-optimised intake system. Miller and Atkinson valve timings were examined using a detailed 1D model (AVL BOOST). Indicated specific fuel consumption (ISFC) was improved while maintaining effective compression ratio constant. However, brake specific fuel consumption (BSFC) rises due to lower IMEP.
Viewing 1 to 30 of 39992