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Emission and tribological studies on nano CuO/Jatropha methyl ester/Synthetic mineral oil in a two-stroke engine.

Bannari Amman Institute of Technology-Anbalagan Ramakrishnan
Vellore Institute of Technology-Govindasamy Rajamurugan, Prabu Krishnasamy
  • Technical Paper
  • 2019-28-0095
To be published on 2019-10-11 by SAE International in United States
In lieu of the increase in the population of automobiles, there is heavy use of fossil fuels and mineral oils. This leads to depletion in fossil fuel and mineral oil which is a by-product of petroleum. We cannot depend on this for a long period of time and which is toxic to the environment. In order to reduce the usage of existing mineral oil for lubrication, a source of non-edible oil from Jatropha Curcus which is available in an abundant and renewable source of alternative lubricant is processed as jatropha methyl ester because of high viscosity and density and blended with base oil which reduces the pollution. To increase the antiwear properties of the lubricating oil nano copper oxide particle additive are blend with the base oil which is tested in a two-stroke engine. Emission and tribological effects have been tested. There are chances of them being depleted in a short span of years. As a replacement for mineral oil, varies vegetable oils are taken up for research purpose in order to use them as…

Experimental Studies on Liquid Phase LPG Direct Injection on a Two-Stroke SI Engine

SAE International Journal of Engines

Indian Institute of Technology Madras, India-Adwitiya Dube, M. Vivekanand, A. Ramesh
  • Journal Article
  • 03-12-03-0023
Published 2019-05-31 by SAE International in United States
Directly injecting fuel in two-stroke spark-ignition (2S-SI) engines will significantly reduce fuel short-circuiting losses. The liquid phase liquefied petroleum gas (LPG) DI (LLDI) mode has not been studied on 2S-SI engines even though this fuel is widely used for transportation. In this experimental work a 2S-SI gasoline-powered engine used on three-wheelers was modified to operate in LLDI mode with an electronic engine controller. The influences of injection pressure (IP), end of injection (EOI) timing, location of the spark plug, and type of injector on performance, combustion, and emissions were studied at different operating conditions. EOI close to bottom dead center with the spark plug located near the exhaust port was the most suitable for the LLDI mode which significantly enhanced the fuel trapping efficiency and improved the thermal efficiency. At 70% throttle condition the brake thermal efficiency increased from 19% to 25.6% and there was an 87% reduction in hydrocarbon (HC) emission compared to liquid phase LPG manifold injection. The use of multi-hole injector extended the maximum power output due to better in-cylinder mixture formation,…
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Quantification of Windage and Vibrational Losses in Flexure Springs of a One kW Two-Stroke Free Piston Linear Engine Alternator

West Virginia University-Nima Zamani Meymian, Nigel Clark, Jayaram Subramanian, Gregory Heiskell, Derek Johnson, Fereshteh Mahmudzadeh, Mahdi Darzi, Terence Musho, Parviz Famouri
Published 2019-04-02 by SAE International in United States
Methods to quantify the energy losses within linear motion devices that included flexural springs as the main suspension component were investigated. The methods were applied to a two-stroke free-piston linear engine alternator (LEA) as a case study that incorporated flexure springs to add stiffness to the mass-spring system. Use of flexure springs is an enabling mechanism for improving the efficiency and lifespan in linear applications e.g. linear engines and generators, cryocoolers, and linear Stirling engines. The energy loss due to vibrations and windage effects of flexure springs in a free piston LEA was investigated to quantify possible energy losses. A transient finite element solver was used to determine the effects of higher modes of vibration frequencies of the flexure arms at an operational frequency of 65 Hz. Also, a computational fluid dynamics (CFD) solver was used to determine the effects of drag force on the moving surfaces of flexures at high frequencies. A parametric study was performed to understand the effects of geometrical and operational parameters including the diameter of flexures, gap width between flexure…
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Effects of Intake Port Structures and Valve Timings on the Scavenging Process in a Two-Stroke Poppet Valve Diesel Engine

China North Engine Research Institute-Wei Liu, Yan Zhang, Bo Yu, Yaozong Li, Ziyu Wang
Published 2019-04-02 by SAE International in United States
The two-stroke operation is one of the most effective approaches to significantly increase the torque and power of a 4-stroke engine without the necessary requirement of intensifying the engine. Scavenging process is one of the key factors determining the performance of the two-stroke engine. In this work, a structure of top entry intake ports with poppet valves was employed on a 2-stroke single cylinder diesel engine with the conventional horizontal intake ports replaced. By this way, the reversed tumble flows in the cylinder were formed during the intake process to improve the scavenging performance of 2-stroke operation. In the meanwhile, the effects of valve timings and intake port structures on scavenging processes were estimated respectively through the1D and 3D simulation of the gas exchange process.Results show that compared to the conventional horizontal intake port case, the reversed tumble flow created by the top-entry intake port led to a lower air short-circuiting rate and a higher scavenging efficiency. Furthermore, by advancing the exhaust valve opening the exhaust gas was discharged more sufficiently and the intake backflow…
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Achieving Ultra-Low Oil Consumption in Opposed Piston Two-Stroke Engines

Achates Power, Inc.-Dan Chown, John Koszewnik, Ryan MacKenzie, Dan Pfeifer, Brian Callahan, Manny Vittal
Da Vinci Technologies-Kent Froelund
Published 2019-01-15 by SAE International in United States
The opposed piston two-stroke (OP2S) engine architecture is widely recognized for its improved fuel efficiency relative to a four-stroke engine. Achates Power Inc. seeks to demonstrate the market readiness of the OP2S engine by proving competitive in other important areas, one of which is oil consumption. Achieving oil consumption competitive to modern four-stroke engines is thus a key step in bringing OP2S technology to market. Two-stroke engines have historically suffered from higher engine lube oil consumption and subsequent emissions and durability challenges. This is primarily due to two main features of traditional two-stroke engines; the direct interaction of the piston skirt and rings with the intake and/or exhaust ports, which results in a direct leak path for lube oil to the combustion chamber and/or exhaust manifold, and crankcase-scavenged architectures which entrain oil into air being pumped through the crankcase. The OP2S engine architecture directly addresses these concerns by utilizing intake and exhaust manifolds, a closed crankcase system, and oil control rings which operate outboard of the ports. Previous work has shown the importance of careful…
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Two Stroke Gasoline Direct Injection Strategy Optimization Using 1D and 3D Analysis Tool

College of Engineering Pune-Yuvraj Chavan, Chandrashekar Sewatkar
Published 2019-01-09 by SAE International in United States
A two-stroke engine is a type of internal combustion (IC) engine that completes the power cycle in one crankshaft revolution, which is half the number in comparison with four-stroke engine. Spark Ignition (SI) two-stroke engines are commonly found in the small power tools such as chain saw and scooter. While Compression Ignition (CI) engines are commonly used in large machines such as marine propulsion and electricity generator.Two-stroke engines have several inherent advantages over four stroke engines such as simple and compact design, high power-to-weight ratio, lower NOx emissions etc. The piston of the two-stroke reciprocating engine takes over valve functions in order to obtain a power stroke for each revolution of the crankshaft. The valve overlap period in case of two stroke SI engines is greater than four stroke SI engines; this loss of fresh fuel is called short-circuiting [1]. This accounts for major source of hydro-carbon (HC) emissions and increased specific fuel consumption in two stroke SI engines. Independent fuel supply system could easily reduce inherent disadvantages of higher hydrocarbon emissions and low fuel…
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On the Effect of the Injector Position on Fuel-Air Mixture Preparation in a Two-Stroke GDI Engine

Università degli Studi di Firenze-Francesco Balduzzi, Luca Romani, Andrea Tanganelli, Simone Bigalli, Giovanni Ferrara
Published 2018-10-30 by SAE International in United States
Modern injection systems are characterized by low cost, light weight and diversified components based on a mature technology. In addition, the constant growth of computational resources allows an in-depth understanding and control of the injection process. In this scenario, increasing interest is presently being paid to understand if an application of such technologies to small two-stroke engines could lead to a return to popularity in place of the more widespread use of the four-stroke engine. Indeed, the possibility of achieving a drastic reduction of both specific fuel consumption and pollutant emissions would completely reverse the future prospect of the two-stroke engine. The authors in previous studies developed a low pressure direct injection (LPDI) system for a 300 cm3 two-stroke engine that was ensuring a performance consistent with a standard four-stroke engine of similar size. The main drawbacks of the system were the large time required for delivering the fuel and the incomplete vaporization in some working conditions, due to the large size of the injected droplets. In this study, the use of a single high…
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Influence of Ethanol and 2-Butanol Blended Fuels on Combustion and Emissions in a Small Displacement Two Stroke Engine

Andreas Stihl AG & Co. KG-Tilman Seidel
Graz University of Technology-Stephan Jandl, Stephan Schmidt, Pascal Piecha, Hans-Juergen Schacht
Published 2018-10-30 by SAE International in United States
Small displacement two-stroke engines are cheap and low-maintenance propulsion systems and commonly used in scooters, recreation vehicles and handheld power-tools. The restriction by emission legislation and the increasing environmental awareness of end users as well as decreasing energy resources cause a rethinking in the development of propulsion systems and fuels in these fields. Despite recent improvements of electric powertrains, two stroke engines are the challenged propulsion system in high performance handheld power tools at the moment. The reasons are the extraordinary high power to weight ratio of two-stroke engines, the high energy density of liquid fuels and the reliability of the product with respect to extreme ambient conditions. Nevertheless, further improvements on emissions and fuel consumption of small displacement two-stroke engines can be realized.This research is focused on the use of alternative renewable fuels, so called biofuels, like ethanol and 2-butanol in small displacement two-stroke engines. The different physical and chemical properties of ethanol and 2-butanol can have a positive impact on the combustion process and emission composition and are a possibility to contribute future…
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Technologies to Achieve Future Emission Legislations with Two Stroke Motorcycles

Graz University of Technology-Roland Oswald, Roland Kirchberger, Stefan Krimplstatter
Published 2018-10-30 by SAE International in United States
Increasingly stringent emission regulations force manufacturers of two wheelers to develop low emission motorcycle concepts. Especially for small two-stroke engines with symmetrical port timing structure, causing high HC-emissions due to scavenge losses, this is a challenging demand that can only be met with alternative mixture formation strategies and by intensifying the use of modern development tools. Changing from EU4 to EU5, emission legislation will not only have an impact on the improvement of internal combustion but will also drastically change the after-treatment system.Nowadays, small two-stroke engines make use of a simple carburetor for external mixture preparation. The cylinders are scavenged by air/fuel mixtures. Equipped with exhaust gas after-treatment systems, such as secondary air with two or three catalytic converters, the emission limits for EURO 4 homologation can be achieved with carbureted engines. An increased number of catalytic converters in the exhaust system reduces the performance of a carbureted two stroke engine and has therewith no advantage in comparison to a four stroke engine.Electronically controlled direct injection systems with low pressure (SETC 2008-32-0059), reducing the untreated…
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Overview of Different Gas Exchange Concepts for Two-Stroke Engines

Graz University of Technology-Stefan Sturm, Stephan Schmidt, Roland Kirchberger
Published 2018-10-30 by SAE International in United States
The concept of a loop scavenged two-stroke engine, controlling the intake and exhaust port by the moving piston, is a proven way to realize a simple and cheap combustion engine. But without any additional control elements for the gas exchange this concept quickly reaches its limits for current emission regulations. In order to fulfil more stringent emission and fuel consumption limits with a two-stroke engine, one of the most important measures is to avoid scavenging losses of fuel and oil. Additionally, it is necessary to follow a lambda = 1 concept for a 3-way exhaust gas after-treatment.Therefore, using internal mixture preparation systems in combination with different concepts to control the gas exchange process, the two-stroke engine could become a choice for automotive applications, especially as a Range Extender in a Plugin Hybrid Electric Vehicle (PHEV). As various scavenging concepts and several mixture preparation systems can be used for 2-stroke hybrid propulsion, the pros and cons of different concept combinations have to be compared and weighted for an optimum solution.To get an overview of possible designs…
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