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Journal articles on the topic 'Two-stroke engines performance'
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1
Shokrollahihassanbarough, Farzad, Ali Alqahtani, and Mirosław Wyszynski. "Thermodynamic simulation comparison of opposed two-stroke and conventional four-stroke engines." Combustion Engines 162, no. 3 (August 1, 2015): 78–84. http://dx.doi.org/10.19206/ce-116867.
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Today’s technology leveraging allows OP2S (Opposed Piston 2-Stroke) engine to be considered as an alternative for the conventional four-stroke (4S) engines as mechanical drive in various applications, mainly in transportation. In general, OP2S engines are suited to compete with conventional 4-stroke engines where power-to-weight ratio, power-to-bulk volume ratio and fuel efficiency are requirements. This paper does present a brief advent, as well as the renaissance of OP2S engines and the novel technologies which have been used in the new approach. Also precise thermodynamic benefits have been considered, to demonstrate the fundamental efficiency advantage of OP2S engines. Hence, simulations of two different engine configurations have been taken into consideration: a one-cylinder opposed piston engine and two-cylinder conventional piston four-stroke engine. In pursuance of fulfilling this goal, the engines have been simulated in AVL Boost™ platform which is one of the most accurate Virtual Engine Tools, to predict engine performance such as combustion optimization, emission and fuel consumption. To minimize the potential differences of friction losses, the bore and stroke per cylinder are taken as constant. The closed-cycle performance of the engine configurations is compared using a custom analysis tool that allows the sources of thermal efficiency differences to be identified and quantified. As a result, brake thermal efficiency, power and torque of OP2S engine have been improved compared to conventional engines while emission concern has been alleviated.
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Ramakrishnan, V., R. Thamilarasan, and K. Purushothaman. "Performance Evaluation of EGR in Two Stroke I.C. Engine." Applied Mechanics and Materials 812 (November 2015): 60–63. http://dx.doi.org/10.4028/www.scientific.net/amm.812.60.
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Petrol engines are known for their simplicity, low cost and maintenance. However nowadays use of two stroke petrol engines are fading away from the market. An attempt has been made here to revive the use of these old engines by using Exhaust Gas Recirculation (EGR) to improve performances.Short circuiting of fresh charge is an important contributing factor for reduction in performance in two stroke engines. Our project is aimed to reduce short circuiting of fresh charge by admitting cooled exhaust gas to pass through reed valves fitted at the upper end of the transfer passage, in a crank case scavenged two stroke engine. Reed valves were provided at the upper end of the transfer passage using a flange arrangement. Exhaust gas temperature at around 4000 was cooled using a heat exchanger to avoid pre-ignition inside the engine cylinder. The performance of the engine is tested using eddy current dynamometer. The study indicates an appreciable decrease in specific fuel consumption and in HC/CO emissions in a crank case scavenged two stroke engine.
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Kenny, R. G. "Developments in Two-Stroke Cycle Engine Exhaust Emissions." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 206, no. 2 (April 1992): 93–106. http://dx.doi.org/10.1243/pime_proc_1992_206_165_02.
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This paper is concerned with the exhaust emissions from two-stroke cycle spark ignition engines and the means being investigated to reduce them. The simple two-stroke engine has inherently low levels of NOx emissions and high levels of hydrocarbon emissions. The reasons for these emissions characteristics are explained by reference to the open literature. The two-stroke engine is used in a wide range of applications including low-cost, low-output mopeds and high-performance motorcycles. More recently there has been a resurgence of interest in the two-stroke as an alternative to the four-stroke engine for automotive use. A number of the recently reported approaches to emissions control are reviewed, including the use of exhaust oxidation catalysts in simple low-cost engines and direct fuel injection on more costly, multi-cylinder engines.
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Sapate, Kumar D., and A. N. Tikekar. "Mechanical Modifications to Convert Small Two Strokes Carbureted Engine to Electronic Fuel Injection System Engine to Reduce Emission and Fuel Consumption." Advanced Materials Research 768 (September 2013): 213–17. http://dx.doi.org/10.4028/www.scientific.net/amr.768.213.
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The evolution of four stroke engines and improved environmental pollution control norms has pushed the two-stroke engines towards obsolescence due to their inherent design problems. This has made the existing manufacturers & users of two-stroke engines a setback. In this paper attempt has been made to high light the performance parameters in respect of fuel efficiency and emission control. In this research work an effort is made to retrofit the commonly used two stroke engine for optimal performance by using EFI engine. It mainly includes injector locations with reference to spark plug which decides the combustion efficiency of engine. It also includes the location of different sensors and subsequent modification of silencer. As the automobile engine has to operate at higher speeds, proper and firm mounting of different electronic part is essential which affects the performance of engine. After mechanical modification of engine with EFI system it is tested by connecting it to dynamometer. The results are compared with that of carbureted engine.
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Kyrtatos, N. P., and I. Koumbarelis. "A Three-Zone Scavenging Model for Two-Stroke Uniflow Engines." Journal of Engineering for Gas Turbines and Power 110, no. 3 (July 1, 1988): 531–37. http://dx.doi.org/10.1115/1.3240167.
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A three-zone scavenging model for two-stroke uniflow engines was developed and used in conjunction with a control-volume-type engine simulation code for performance prediction of long stroke uniflow-type marine engines. In this model it is attempted to simulate the three different regions perceived to exist inside the cylinder during scavenging, namely the air, mixing, and combustion products regions, by modeling each region as a separate control volume. Two time-varying coefficients are used to specify the rates of entrainment of the air and the burned gases into the mixing region. Results of the use of the model for predicting the performance of a large marine two-stroke engine are presented.
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Haddad, S. D. "Piston Motion and Thermal Loading Analyses of Two-Stroke and Four-Stroke Cycle Engines for Locomotives." Journal of Engineering for Gas Turbines and Power 111, no. 3 (July 1, 1989): 536–42. http://dx.doi.org/10.1115/1.3240288.
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Two-stroke cycle and four-stroke cycle diesel engines are in use in rail traction, with the four-stroke cycle design dominating the field. Cycle simulations using computer programs have shown that the conventional two-stroke cycle is somewhat inferior to its four-stroke cycle counterpart in combustion efficiency and thermal loading. Research at Sulzer concluded that the conventional two-stroke cycle engine is not very suitable for locomotive application. A survey by Ricardos, based on an investigation of engines in current production for traction application, suggested that there are potentials in two-stroke cycle design. This paper presents a summary of the results of a research project concerned with comparison of two well-proven typical locomotive diesel engines, one with a two-stroke cycle and the other with a four-stroke cycle. Performance, mechanical loading, thermal loading, and vibration were chosen as parameters to be investigated to provide information on the status of the two cycles in relation to power range, fuel consumption, reliability, and durability, with a view to assisting the users of locomotive engines to make the correct choice.
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Boretti, Albert. "Design of Direct Injection Jet Ignition High Performance Naturally Aspirated Motorcycle Engines." Designs 3, no. 1 (February 5, 2019): 11. http://dx.doi.org/10.3390/designs3010011.
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Thanks to the adoption of high pressure, direct injection and jet ignition, plus electrically assisted turbo-compounding, the fuel conversion efficiency of Fédération Internationale de l'Automobile (FIA) F1 engines has been spectacularly improved up to values above 46% peak power, and 50% peak efficiency, by running lean of stoichiometry stratified in a high boost, high compression ratio environment. Opposite, Federation Internationale de Motocyclisme (FIM) Moto-GP engines are still naturally aspirated, port injected, spark ignited, working with homogeneous mixtures. This old fashioned but highly optimized design is responsible for relatively low fuel conversion efficiencies, and yet delivers an outstanding specific power density of 200 kW/liter. The potential to improve the fuel conversion efficiency of Moto-GP engines through the adoption of direct injection and jet ignition, prevented by the current rules, is herein discussed based on simulations. As two-stroke engines may benefit from direct injection and jet ignition more than four-stroke engines, the opportunity of a return of two-stroke engines is also argued, similarly based on simulations. About the same power, but at a better fuel efficiency, of today’s 1000 cm3 four stroke engines, may be obtained with lean stratified direct injection jet ignition engines, four-stroke of 1450 cm3, or two-stroke of 1050 cm3. About the same power and fuel efficiency may also be delivered with stoichiometric engines direct injection jet ignition two-stroke of 750 cm3.
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Hooper, P. R., T. Al-Shemmeri, and M. J. Goodwin. "Advanced modern low-emission two-stroke cycle engines." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 225, no. 11 (August 4, 2011): 1531–43. http://dx.doi.org/10.1177/0954407011408649.
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This paper reviews recent engines and associated technology offering potential low-emission two-stroke cycle operation for a range of applications. The study considers and discusses successfully applied modern production engines together with concepts exploring advanced possibilities for future application. The published results from research and development projects and the data from available technology are compared in terms of the specific performance. The paper does not compare combustion strategies or fluid dynamic aspects of two-stroke cycle engines but does consider and compare the data from engines using the crankcase, external, and stepped piston scavenging intended for automotive, marine, and defence applications.
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Arabaci, Emre. "Performance analysis of a novel six-stroke otto cycle engine." Thermal Science, no. 00 (2020): 144. http://dx.doi.org/10.2298/tsci190926144a.
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In this study, a simulation model with finite time thermodynamics was presented for an Otto cycle six-stroke engine. In this six-stroke engine, two free strokes occur after the exhaust stroke. These free strokes cause the engine to have higher thermal efficiency. Due to high thermal efficiency, these six-stroke engines can be used in hybrid electric vehicles. In this study, the effect of residual gas fraction and stroke ratio on the effective power and effective thermal efficiency were investigated. In addition, heat balance was obtained for the engine and the use of fuel energy in the engine was examined with the help of performance fractions. In the simulation model, the results are quite realistic as the working fluid was assumed to consist of fuel-air-residual gases mixture.
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Wang, Yang, Wuqiang Long, Jingchen Cui, Xin Wang, Hua Tian, and Xiangyu Meng. "Research on two-stroke compression release braking performance of a variable mode valve actuation system." International Journal of Engine Research 21, no. 9 (December 24, 2019): 1696–708. http://dx.doi.org/10.1177/1468087419894449.
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In order to enhance the braking safety and improve the fuel economy and emission of heavy-duty engines, a variable mode valve actuation system which can switch operation modes flexibly among four-stroke driving, two-stroke compression release braking, and cylinder deactivation modes on a four-stroke engine was developed in this article. The switching was controlled by the four-stroke driving module and the two-stroke braking module, both of which have two states: effective state and failure state. Besides, a full-cycle numerical model of a six-cylinder turbocharged engine was established for the performance analysis of two-stroke compression release braking mode. The orthogonal design method was introduced in the present study to obtain the optimum valve parameters which can result in high braking power and maintain the maximum cylinder pressure at a lower level at the same time. Then, the two-stroke compression release brake braking power with the optimum valve parameters was compared with four-stroke compression release braking power. Meanwhile, the two-stroke braking cam profile of the variable mode valve actuation system was designed according to the optimum valve parameters, and the two-stroke braking performance with the dynamic valve lift of the variable mode valve actuation system was validated by the numerical model including the hydraulic system. The results indicated that a higher engine speed leads to higher braking power at the same valve lift. Besides, two-stroke compression release brake braking power of the variable mode valve actuation system achieved 525.3 kW at 2600 r/min and 358.1 kW at 1900 r/min, 52.9% and 71.3% higher than four-stroke compression release braking power, respectively. Although the two-stroke compression release brake braking power with dynamic valve lift is slightly less than that with the optimum valve parameters, it is still much higher than that of the four-stroke compression release braking power. Therefore, it has a good application prospect for heavy-duty engines.
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Taranin, A. G. "USAGE FEATURES OF THE ELECTRONIC INDICATORS FOR SHIP’S AND SHORE POWER SUPPLY TWO– STROKE INTERNAL COMBUSTION ENGINES (DIESEL ENGINES)." EurasianUnionScientists 5, no. 4(73) (May 12, 2020): 42–49. http://dx.doi.org/10.31618/esu.2413-9335.2020.5.73.682.
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The present publication illuminate the tasks as follows: Electronic indicator proper usage at four–stroke internal combustion engines (diesel engines) indication; Indication results & diagram proper transfer to PC; indicator diagram top dead center TDC correction and engine performance data output values such as PMI–mean indicated pressure, PME–mean effective pressure, NIND–indicated power and NEFF–effective power proper calculations for each cylinder and engine total.
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Taranin, A. G. "USAGE FEATURES OF THE ELECTRONIC INDICATORS FOR SHIP’S AND SHORE POWER SUPPLY TWO– STROKE INTERNAL COMBUSTION ENGINES (DIESEL ENGINES)." National Association of Scientists 1, no. 27(54) (May 14, 2020): 39–47. http://dx.doi.org/10.31618/nas.2413-5291.2020.1.54.187.
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The present publication illuminate the tasks as follows: Electronic indicator proper usage at four–stroke internal combustion engines (diesel engines) indication; Indication results & diagram proper transfer to PC; indicator diagram top dead center TDC correction and engine performance data output values such as PMI–mean indicated pressure, PME–mean effective pressure, NIND–indicated power and NEFF–effective power proper calculations for each cylinder and engine total
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Kutlar, Osman Akin, and Fatih Malkaz. "Two-Stroke Wankel Type Rotary Engine: A New Approach for Higher Power Density." Energies 12, no. 21 (October 26, 2019): 4096. http://dx.doi.org/10.3390/en12214096.
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The Wankel engine is a rotary type of four-stroke cycle internal combustion engine. The higher specific power output is one of its strong advantages. In Wankel rotary engine, every eccentric shaft revolution corresponds to one four-stroke cycle, whereas conventional reciprocating engine fulfills four-stroke cycle in two crankshaft revolutions. This means the power stroke frequency is twice that of conventional engines. Theoretically, application of two-stroke cycle on Wankel geometry will duplicate the power stroke frequency. In this research, a single-zone thermodynamic model is developed for studying the performance characteristic of a two-stroke Wankel engine. Two different port timings were adapted from the literature. The results revealed that late opening and early closing port geometry (small opening area) with high supercharging pressure has higher performance at low speed range. However, as the rotor speed increases, the open period of the port area becomes insufficient for the gas exchange, which reduces power performance. Early opening and late closing port geometry (large opening area) with supercharging is more suitable in higher speed range. Port timing and area, charging pressure, and speed are the main factors that characterize output performance. These preliminary results show a potential for increasing power density by applying two-stroke cycle of the Wankel engine.
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Tsitsilonis, Konstantinos-Marios, Gerasimos Theotokatos, Nikolaos Xiros, and Malcolm Habens. "Systematic Investigation of a Large Two-Stroke Engine Crankshaft Dynamics Model." Energies 13, no. 10 (May 14, 2020): 2486. http://dx.doi.org/10.3390/en13102486.
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The crankshaft dynamics model is of vital importance to a multitude of aspects on engine diagnostics; however, systematic investigations of such models performance (especially for large two-stroke diesel engines that are widely used in the power generation and shipping industries) have not been reported in the literature. This study aims to cover this gap by systematically investigating the parameters that affect the performance of a two-stroke diesel engine crankshaft dynamics model, such as the numerical scheme as well as the engine components inertia and friction. Specifically, the following alternatives are analysed: (a) two optimal performing numerical schemes, in particular, a stiff ordinary differential equations (ODE) solver and a fast solver based on a piecewise Linear Time-Invariant (LTI) scheme method, (b) the linear and the non-linear inertia-speed approaches, and (c) three engine friction submodels of varying complexity. All the potential combinations of the alternatives are investigated, and the crankshaft dynamics model performance is evaluated by employing Key Performance Indicators (KPIs), which consider the results accuracy compared to the measured data, the computational time, and the energy balance error. The results demonstrate that the best performing combination includes the stiff ODE solver, the constant inertia-speed approach and the most simplistic engine friction submodel. However, the LTI numerical scheme is recommended for applications that require fast response due to the significant savings in computational time with an acceptable compromise in the model results accuracy.
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Herrmann, Samara, Macklini Dalla Nora, and Thompson Diordinis Metzka Lanzanova. "Development of a Two-Stroke Cycle Engine for Use in the Agricultural Aviation Sector." Journal of Aerospace Technology and Management, no. 12 (November 21, 2020): 52–61. http://dx.doi.org/10.5028/jatm.cab.1155.
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Reciprocating internal combustion engines have wide application in agricultural, recreational and experimental aircraft, resulting from their low cost and less complex maintenance compared to other engines. Thus, this work analyzed the performance of a conventional four-stroke engine operating in the two-stroke cycle by means of direct fuel injection and mechanical air supercharging. The use of a supercharger was essential in this design to provide adequate gas exchange inside the cylinder during the long valve overlap required, while direct fuel injection made it possible to reduce the short circuit of air-fuel mixture to the exhaust. Due to the double ignition frequency compared to a four-stroke engine, it was possible to obtain a large power density (40 kW/L) at a speed of 2400 rpm, also a specific fuel consumption of 270 g/kWh with gasoline and 400 g/kWh with ethanol. The use of ethanol in replacement of gasoline made it possible to operate at full load (160 Nm/L) at 800 rpm without the occurrence of knocking combustion.
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Athafah, Noor H., and Adei M. Salih. "Effect of Octane Number on Performance and Exhaust Emissions of an SI Engine." Engineering and Technology Journal 38, no. 4A (April 25, 2020): 574–85. http://dx.doi.org/10.30684/etj.v38i4a.263.
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Spark ignition engines are very popular engines that they are running millions of vehicles all over the world. This engine emits many harmful pollutants, such as CO, UHC, and NOX. In this paper, the impact of gasoline octane number on the engine performance and exhaust emissions was studied. In the tests, four-cylinder, four-stroke engine, and two variable octane numbers (RON83 and 94.5) were used. The engine was run at different engine speeds and loads. The results from the experimental study indicated that the brake specific fuel consumption (bsfc) of RON94.5 was higher than RON83 by 13.93%, while the brake thermal efficiency (ƞbth) was higher for RON83 compared to RON94.5 by 12.31%. The emitted emissions for the tested fuels were high when RON83 was used compared to RON94.5 by 65.52%, 49.11%, and 57.33% for CO, UHC, and NOX, respectively.
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Llamas, Xavier, and Lars Eriksson. "Control-oriented modeling of two-stroke diesel engines with exhaust gas recirculation for marine applications." Proceedings of the Institution of Mechanical Engineers, Part M: Journal of Engineering for the Maritime Environment 233, no. 2 (May 11, 2018): 551–74. http://dx.doi.org/10.1177/1475090218768992.
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Large marine two-stroke diesel engines are widely used as propulsion systems for shipping worldwide and are facing stricter NO x emission limits. Exhaust gas recirculation is introduced to these engines to reduce the produced combustion NO x to the allowed levels. Since the current number of engines built with exhaust gas recirculation is low and engine testing is very expensive, a powerful alternative for developing exhaust gas recirculation controllers for such engines is to use control-oriented simulation models. Unfortunately, the same reasons that motivate the use of simulation models also hinder the capacity to obtain sufficient measurement data at different operating points for developing the models. A mean value engine model of a large two-stroke diesel with exhaust gas recirculation that can be simulated faster than real time is presented and validated. An analytic model for the cylinder pressure that captures the effects of changes in the fuel control inputs is also developed and validated with cylinder pressure measurements. A parameterization procedure that deals with the low number of measurement data available is proposed. After the parameterization, the model is shown to capture the stationary operation of the real engine well. The transient prediction capability of the model is also considered satisfactory which is important if the model is to be used for exhaust gas recirculation controller development during transients. Furthermore, the experience gathered while developing the model about essential signals to be measured is summarized, which can be very helpful for future applications of the model. Finally, models for the ship propeller and resistance are also investigated, showing good agreement with the measured ship sailing signals during maneuvers. These models give a complete vessel model and make it possible to simulate various maneuvering scenarios, giving different loading profiles that can be used to investigate the performance of exhaust gas recirculation and other controllers during transients.
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Kishan, S., S. R. Bell, and J. A. Caton. "Numerical Simulations of Two-Stroke Cycle Engines Using Coal Fuels." Journal of Engineering for Gas Turbines and Power 108, no. 4 (October 1, 1986): 661–68. http://dx.doi.org/10.1115/1.3239962.
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An analytical model of a two-stroke cycle, reciprocating, compression ignition engine was used to investigate the ignition and combustion characteristics of coal/water slurry fuels. The engine cycle simulation was based on a thermodynamic analysis of the cylinder contents and consisted of models for the injection, ignition, combustion, mixing, heat transfer, work, and scavenging processes. The thermodynamic analysis resulted in a set of first-order nonlinear, ordinary differential equations which were numerically integrated to obtain instantaneous cylinder gas, droplet, and particle conditions. The simulation results were first compared to experimental data from a large, slow-speed (120 rpm) engine using a coal/water slurry fuel. Complete validation of the model was not possible due to the lack of detailed experimental data, but comparisons are presented which indicate general agreement between measured and computed values. The model was then used to predict the performance of an engine representative of a locomotive medium-speed engine. Engine and fuel parameters were varied to study their effect on ignition and combustion of the coal/water slurry fuel and on the indicated engine performance. Increases in the inlet air temperature improved the ignition and combustion characteristics. Lower equivalence ratios or smaller particle sizes resulted in higher thermal efficiencies. Also, higher reactive coal led to increased cylinder pressures and higher thermal efficiencies due to faster burning rates.
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Masjuki, H. H., and M. A. Maleque. "Wear, Performance and Emissions of a Two-Stroke Engine Running on Palm Oil Methyl Ester Blended Lubricant." Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 210, no. 4 (December 1996): 213–19. http://dx.doi.org/10.1243/pime_proc_1996_210_503_02.
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Results of study on wear of piston rings, engine performance and exhaust gas emissions of palm oil methyl ester (POME) as a lubricating oil additive in a two-stroke gasoline engine test are presented. Piston ring wear behaviour was monitored as a function of running time. The power output and brake specific fuel consumption of the engine were measured at different speeds. Varnish/lacquer and carbon deposit on the spark plug electrode, cylinder and piston heads as well as exhaust gas (CO2, CO and O2) emission were measured. For comparison purposes, two types of commercial lubricating oils, viz. oil A and oil B were used. The wear resistance of piston rings with POME blending lubrication was found to be greater than the pure commercial oil lubrication. Other results indicate that the POME acts as an additive which improves the engine performance and exhaust emissions of two-stroke gasoline engines.
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Luján, José Manuel, Héctor Climent, Pablo Olmeda, and Víctor Daniel Jiménez. "Heat transfer modeling in exhaust systems of high-performance two-stroke engines." Applied Thermal Engineering 69, no. 1-2 (August 2014): 96–104. http://dx.doi.org/10.1016/j.applthermaleng.2014.04.045.
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Huang, R. F., M.-P. Hsu, W. L. Chen, and K. Lee. "On the tuning pipe of a two-stroke engine for scooter-type motorcycles." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 213, no. 8 (August 1, 1999): 861–66. http://dx.doi.org/10.1243/0954406991522464.
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Engine performance and simultaneous pressure wave histograms in the cylinder and exhaust port were studied in this experiment. The performance of two-stroke engines for scooter-type motorcycles depended greatly on the length and expansion angle of the tuning pipe. The length of the lead-in pipe dominated the phase of the starting point of reflected expansion waves. The full length determined the timing of reflected expansion waves. The first expansion angle of the exhaust pipe must be limited to a small value and then expanded gradually to give the desired diameter. The effect of the muffler was also discussed. There was an optimal distance between the end of the tuning pipe and the spacer of the muffler to obtain a maximum power output.
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Masi, Massimo, Matteo Pregrasso, and Paolo Gobbato. "A Practical Design Approach to Improve the Charging Efficiency of a Small Two-Stroke High Speed Engine Based on Basic CFD." E3S Web of Conferences 197 (2020): 06005. http://dx.doi.org/10.1051/e3sconf/202019706005.
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The paper deals with the optimisation of the charging efficiency in a small two-stroke high-speed engine according to well-established design guidelines. The aim is to present the method successfully used in the preliminary screening of the performance improvement attainable in a crank-case-compression engine by design modifications to the transfer ports and manifolds. The method applies a basic CFD model of the steady-state flow across the cylinder block validated against experimental tests at the discharge flow bench. This model is used to approximate the actual scavenging process through a transient simulation of the cold flow across the cylinder inside which the piston is fixed at the bottom centre. A fast assessment of the charging efficiency is permitted by a transported passive scalar implemented in the model to easily estimate all the parameters needed for monitoring the effectiveness of the scavenging process at each crankangle. This practical design approach has been applied to the geometry of a Schnürle-type loop-scavenged 125cc single-cylinder engine compliant with the 2018 FIA homologation form for the KF2 karting competition category. The maximum increase of indicated mean effective pressure expected according to the comparison between the CFD simulations of the original and the modified design of the transfer ports is approximately equal to 4%. This result demonstrates that the CFD analyses are sensitive to the limited modifications commonly needed to tune two-stroke racing-engines and confirms that the suggested design approach can be profitably employed by engineers and technicians involved in the design of small two-stroke highspeed engines.
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Feng, Yongming, Haiyan Wang, Ruifeng Gao, and Yuanqing Zhu. "A Zero-Dimensional Mixing Controlled Combustion Model for Real Time Performance Simulation of Marine Two-Stroke Diesel Engines." Energies 12, no. 10 (May 24, 2019): 2000. http://dx.doi.org/10.3390/en12102000.
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The paper presents a performance prediction model of marine low-speed two-stroke diesel engines based on an advanced MCC (mixture controlled combustion) model coupled with a fuel injection model. Considering the time of real calculation, the so-called “concentrated exhausting gas” scavenging model and the working process model are used in the present work, and improved by introducing the ratio of pure combustion product over the total gas mass in the cylinder as an expression of the working medium components. The reaction rate model in the zero-dimensional MCC model is improved by introducing the fraction of combustion product in the fuel spray, and the relationship between the combustion model and scavenging quality is established. Meanwhile, the combustion model was simplified in the diffusion combustion phases and integrated with the fuel injection model in order to respond to the change of injection profile and injection timing. A large-scale low-speed marine diesel engine was used for a simulation. The results of the whole model are consistent with experimental data and the speed of calculation is fast enough for real time simulation of low speed and medium speed diesel engines. The prediction model can be used in the design and calibration of the electronic control system and performance optimization of the marine two-stroke diesel engine.
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Liang, Xingyu, Ziyang Liu, Kun Wang, Xiaohui Wang, Zhijie Zhu, Chaoyang Xu, and Bo Liu. "Impact of Pilot Injection on Combustion and Emission Characteristics of a Low-Speed Two-Stroke Marine Diesel Engine." Energies 14, no. 2 (January 13, 2021): 417. http://dx.doi.org/10.3390/en14020417.
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Low-speed two-stroke marine diesel engines dominate the modern global long-distance transportation market; with the increasingly stringent regulations, the combustion and emissions of these engines is gaining intense interest. The primary objective of the present study was to understand the effects of air-fuel mixing by pilot injection strategy on the combustion and emission characteristics of the marine diesel engines through a numerical study. Specifically, a computational fluid dynamic (CFD) model was established and validated by experimental data for a typical low-speed two-stroke marine diesel engine. The combustion parameters under different stages were analyzed, including mean in-cylinder temperature and pressure, indicated thermal efficiency (ITE), indicated specific fuel consumption (ISFC), and distribution of fuel-air mixture. Results indicated that, due to the premixing effect, the pilot injection produced unburned soot from the main injection’s ignition as well as decrease the intervals between the middle and final stages of combustion, thus raising the in-cylinder temperature. The interaction between the reduction of soot particles resulted from the increased temperature, and the decrease of the stage intervals led to lower overall boundary heat loss, which improved the effective thermal efficiency. The pilot injection timing and quality, respectively, showed quadratic and linear impact modes on engine performance and emissions.
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Wang, Xinyan, Jun Ma, and Hua Zhao. "Analysis of the effect of bore/stroke ratio and scavenge port angles on the scavenging process in a two-stroke boosted uniflow scavenged direct injection gasoline engine." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 232, no. 13 (November 14, 2017): 1799–814. http://dx.doi.org/10.1177/0954407017735383.
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In this study, a two-stroke boosted uniflow scavenged direct injection gasoline (BUSDIG) engine was proposed and researched to achieve aggressive engine downsizing and downspeeding. Compared to loop or cross scavenged two-stroke engines, the BUSDIG engine can achieve excellent scavenging performance and be operated with higher boost pressure as well as the absence of air and fuel short-circuiting. As a fundamental engine geometric parameter, the bore/stroke (B/S) ratio would directly affect the scavenging process in the uniflow scavenged two-stroke engine. Three-dimensional computational fluid dynamics simulations were used to investigate the scavenging process in the BUSDIG engine with different B/S ratios. Four B/S ratios of 0.66, 0.8, 1, and 1.3 were analyzed. The results indicate that a bigger B/S ratio leads to deteriorated swirl flow motion but better delivery ratio, scavenging efficiency, and charging efficiency. In order to fulfil the potential of the BUSDIG engine with different B/S ratios, two key scavenge port angles, i.e. axis inclination angle (AIA) and swirl orientation angle (SOA), were varied from the baseline design (AIA = 90°, SOA = 20°) to study their effects on the scavenging process for each B/S ratio design. Overall, a larger AIA leads to lower swirl ratio (SR) but achieves better scavenge performance, which is crucial for a large B/S ratio design. A small SOA design leads to noticeably lower SR but superior scavenging performances for a small B/S ratio design. An intermediate SOA, e.g. 10 and 20°, is preferred to improve the scavenging for a large B/S ratio design.
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Weerasinghe, Rohitha, and Sandra Hounsham. "Small Engines as Bottoming Cycle Steam Expanders for Internal Combustion Engines." Journal of Combustion 2017 (2017): 1–8. http://dx.doi.org/10.1155/2017/1742138.
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Heat recovery bottoming cycles for internal combustion engines have opened new avenues for research into small steam expanders (Stobart and Weerasinghe, 2006). Dependable data for small steam expanders will allow us to predict their suitability as bottoming cycle engines and the fuel economy achieved by using them as bottoming cycles. Present paper is based on results of experiments carried out on small scale Wankel and two-stroke reciprocating engines as air expanders and as steam expanders. A test facility developed at Sussex used for measurements is comprised of a torque, power and speed measurements, electronic actuation of valves, synchronized data acquisition of pressure, and temperatures of steam and inside of the engines for steam and internal combustion cycles. Results are presented for four engine modes, namely, reciprocating engine in uniflow steam expansion mode and air expansion mode and rotary Wankel engine in steam expansion mode and air expansion mode. The air tests will provide base data for friction and motoring effects whereas steam tests will tell how effective the engines will be in this mode. Results for power, torque, and p-V diagrams are compared to determine the change in performance from air expansion mode to steam expansion mode.
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Yang, Zhiyuan, Qinming Tan, and Peng Geng. "Combustion and Emissions Investigation on Low-Speed Two-Stroke Marine Diesel Engine with Low Sulfur Diesel Fuel." Polish Maritime Research 26, no. 1 (March 1, 2019): 153–61. http://dx.doi.org/10.2478/pomr-2019-0017.
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Abstract With the implementation and expansion of international sulfur emission control areas, effectively promoted the marine low sulfur diesel fuel (MLSDF) used in marine diesel engines. In this study, a large low-speed, two-stroke, cross-head, common rail, electronic fuel injection marine diesel engine (B&W 6S35ME-B9) was used for the study. According to diesel engine’s propulsion characteristics, experiments were launched respectively at 25%, 50%, 75%, 100% load working conditions with marine low sulfur diesel fuel to analyze the fuel consumption, combustion characteristics and emissions (NOx, CO2, CO, HC) characteristics. The results showed that: Marine diesel engine usually took fuel injection after top dead center to ensure their safety control NOx emission. From 25% to 75% load working condition, engine’s combustion timing gradually moved forward and the inflection points of pressure curve after top dead center also followed forward. While it is necessary to control pressure and reduce NOx emission by delaying fuel injection timing at 100% load. Engine’s in-cylinder pressure, temperature, and cumulative heat release were increased with load increasing. Engine’s CO2 and HC emissions were significantly reduced from 25% to 75% load, while they were increased slightly at 100% load. Moreover, the fuel consumption rate had a similar variation and the lowest was only 178 g/kW·h at 75% load of the test engine with MLSDF. HC or CO emissions at four tests’ working conditions were below 1.23 g/kW·h and the maximum difference was 0.2 or 0.4 g/kW·h respectively, which meant that combustion efficiency of the test engine with MLSDF is good. Although the proportion of NOx in exhaust gas increased with engine’s load increasing, but NOx emissions were always between 12.5 and 13.0 g/kW·h, which was less than 14.4 g/kW·h. Thus, the test engine had good emissions performance with MLSDF, which could meet current emission requirements of the International Maritime Organization.
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Grabowski, Łukasz, Konrad Pietrykowski, and Paweł Karpiński. "Energetic Analysis of the Aircraft Diesel Engine." MATEC Web of Conferences 252 (2019): 05012. http://dx.doi.org/10.1051/matecconf/201925205012.
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The analysis of the distribution of thermal energy generated during the combustion process in internal combustion engines and the estimation of individual losses are important regarding performance and efficiency. The article analyses the energy balance of the designed two-stroke opposed piston diesel engines with offset, i.e. the angle by which the crankshaft at the side of exhaust ports is ahead of the crankshaft at the side of intake ports. Based on the developed zero-dimensional engine model, a series of simulations were performed in steady-state conditions using the AVL BOOST software. The values of individual energy losses, including cooling losses, exhaust gas losses, friction losses were obtained. The influence of decreasing and increasing the offset on the performance of the tested engine was analysed.
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Adair, J., D. Olsen, and A. Kirkpatrick. "Exhaust Tuning of Large-Bore, Multicylinder, Two-Stroke, Natural Gas Engines." International Journal of Engine Research 7, no. 2 (April 1, 2006): 131–41. http://dx.doi.org/10.1243/146808705x58297.
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In this paper, computational modelling of the exhaust system of two types of large-bore, multicylinder, two-stroke engine is performed. The airflow performance of a four-cylinder V-bank Cooper GMV-4TF engine and a six-cylinder in-line Clark TLA engine is simulated. The simulation includes the computation of pressure wave propagation in the exhaust manifold. Using a modified method of the steepest ascent numerical technique, tuned exhaust manifolds are designed for each engine with the objective of reduced NO emissions. The NO reduction is accomplished by increasing the trapped cylinder mass and correspondingly reducing the peak combustion temperature. The simulations predict NO reductions in the range 10–30 per cent as a result of exhaust tuning.
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Qiu, Shuang, Michael Chung Kay Wong, and Paul Chi Hang Li. "Wettability-Based Colorimetric Test Strips for Gasoline/Oil Mixture Differentiation." Advanced Materials Research 1105 (May 2015): 331–34. http://dx.doi.org/10.4028/www.scientific.net/amr.1105.331.
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As inspired by the pH paper for the determination of the acidity levels of solutions, we have developed a wettability-based colorimetric test strip to differentiate the composition of gasoline/oil mixtures. These mixtures are widely used in two-stroke motor engines. A method that is rapid, low cost and simple-to-use will facilitate the differentiation of these gasoline/oil mixtures, and ensure the use of these mixtures in the proper ratios in two-stroke engines for optimized engine performance and endurance. An inverse opal film (IOF) consisting of nanopores was synthesized on the silicon strips. These strips were then functionalized with alkysilanes through chemical vapor deposition. Based on the observation that the silanized nanopores are wetted or not wetted by the gasoline/oil mixtures, we are able to differentiate between the 16:1 and 1:1 mixtures.
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Hill, P. G., and B. Douville. "Relating Burning Rate and NO Formation to Pressure Development in Two-Stroke Diesel Engines." Journal of Energy Resources Technology 119, no. 2 (June 1, 1997): 129–36. http://dx.doi.org/10.1115/1.2794976.
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A multizone thermodynamic method has been developed to determine combustion rate and NO formation from measured cylinder pressures and performance of two-stroke diesel engines. Integral to the analytical method is a nonlinear fit to the combustion chamber heat loss; the fit is consistent with the overall energy balance and with measured fuel consumption rate and exhaust temperature. The method assumes equilibrium combustion properties except for NO, whose relatively slow formation is estimated using the extended Zeldovich mechanism in the post-flame gas during a period of one mixing time. Application of the method to a 2-stroke diesel engine indicates a post-flame mixing time of 0.55 ms or 4 deg crank angle at 1250 rpm, yielding exhaust concentrations of NO considerably less than what would have been expected from equilibrium-then-sudden-freezing considerations.
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Meier, E., and J. Czerwinski. "Turbocharging Systems With Control Intervention for Medium Speed Four-Stroke Diesel Engines." Journal of Engineering for Gas Turbines and Power 111, no. 3 (July 1, 1989): 560–69. http://dx.doi.org/10.1115/1.3240291.
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The turbocharging systems of highly boosted four-stroke diesel engines (BMEP 25 bar/363 psi) have to cope with two basic problems: lack of air and compressor surge at reduced engine speed. In the case of medium speed engines for ship propulsion and stationary applications, the following three control interventions have proved to be successful solutions: (1) waste gating air or exhaust gas at full load and speed, (2) using a compounded or independent exhaust gas driven power turbine that can be shut off at part load and speed, and (3) blowing air from the compressor outlet to the turbine inlet through a controlled bypass. The effect of these control interventions on engine performance is shown by examples and analyzed by means of characteristic quantities for the efficiency of the turbocharging system and the engine. The definitions and meanings of these quantities are explained in the first part of the paper.
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Georgiou, Charalampos, and Ulugbek Azimov. "Analysis and Multi-Parametric Optimisation of the Performance and Exhaust Gas Emissions of a Heavy-Duty Diesel Engine Operating on Miller Cycle." Energies 13, no. 14 (July 20, 2020): 3724. http://dx.doi.org/10.3390/en13143724.
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A major issue nowadays that concerns the pollution of the environment is the emissions emerging from heavy-duty internal combustion engines. Such concern is dictated by the fact that the electrification of heavy-duty transport still remains quite challenging due to limitations associated with mileage, charging speed and payload. Further improvements in the performance and emission characteristics of conventional heavy-duty diesel engines are required. One of a few feasible approaches to simultaneously improve the performance and emission characteristics of a diesel engine is to convert it to operate on Miller cycle. Therefore, this study was divided into two stages, the first stage was the simulation of a heavy-duty turbocharged diesel engine (4-stroke, 6-cylinder and 390 kW) to generate data that will represent the reference model. The second stage was the application of Miller cycle to the conventional diesel engine by changing the degrees of intake valve closure and compressor pressure ratio. Both stages have been implemented through the specialist software which was able to simulate and represent a diesel engine based on performance and emissions data. An objective of this extensive investigation was to develop several models in order to compare their emissions and performances and design a Miller cycle engine with an ultimate goal to optimize diesel engine for improved performance and reduced emissions. This study demonstrates that Miller cycle diesel engines could overtake conventional diesel engines for the reduced exhaust gas emissions at the same or even better level of performance. This study shows that, due to the dependence of engine performance on complex multi-parametric operation, only one model achieved the objectives of the study, more specifically, engine power and torque were increased by 5.5%, whilst nitrogen oxides and particulate matter were decreased by 30.2% and 5.5%, respectively, with negligible change in specific fuel consumption and CO2, as average values over the whole range of engine operating regimes.
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Foteinos, Michael I., Alexandros Papazoglou, Nikolaos P. Kyrtatos, Anastassios Stamatelos, Olympia Zogou, and Antiopi-Malvina Stamatellou. "A Three-Zone Scavenging Model for Large Two-Stroke Uniflow Marine Engines Using Results from CFD Scavenging Simulations." Energies 12, no. 9 (May 7, 2019): 1719. http://dx.doi.org/10.3390/en12091719.
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The introduction of modern aftertreatment systems in marine diesel engines call for accurate prediction of exhaust gas temperature, since it significantly affects the performance of the aftertreatment system. The scavenging process establishes the initial conditions for combustion, directly affecting exhaust gas temperature, fuel economy, and emissions. In this paper, a semi-empirical zero-dimensional three zone scavenging model applicable to two-stroke uniflow scavenged diesel engines is updated using the results of CFD (computational fluid dynamics) simulations. In this 0-D model, the engine cylinders are divided in three zones (thermodynamic control volumes) namely, the pure air zone, mixing zone, and pure exhaust gas zone. The entrainment of air and exhaust gas in the mixing zone is specified by time varying mixing coefficients. The mixing coefficients were updated using results from CFD simulations based on the geometry of a modern 50 cm bore large two-stroke marine diesel engine. This increased the model’s accuracy by taking into account 2-D fluid dynamics phenomena in the cylinder ports and exhaust valve. Thus, the effect of engine load, inlet port swirl angle and partial covering of inlet ports on engine scavenging were investigated. The three-zone model was then updated and the findings of CFD simulations were reflected accordingly in the updated mixing coefficients of the scavenging model.
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Korakianitis, T., L. Meyer, M. Boruta, and H. E. McCormick. "Introduction and Performance Prediction of a Nutating-Disk Engine." Journal of Engineering for Gas Turbines and Power 126, no. 2 (April 1, 2004): 294–99. http://dx.doi.org/10.1115/1.1635394.
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A new type of internal combustion engine and its thermodynamic cycle are introduced. The core of the engine is a nutating nonrotating disk, with the center of its hub mounted in the middle of a Z-shaped shaft. The two ends of the shaft rotate, while the disk nutates. The motion of the disk circumference prescribes a portion of a sphere. A portion of the area of the disk is used for intake and compression, a portion is used to seal against a center casing, and the remaining portion is used for expansion and exhaust. The compressed air is admitted to an external accumulator, and then into an external combustion chamber before it is admitted to the power side of the disk. The accumulator and combustion chamber are kept at constant pressures. The engine has a few analogies with piston-engine operation, but like a gas turbine it has dedicated spaces and devices for compression, burning, and expansion. The thermal efficiency is similar to that of comparably sized simple-cycle gas turbines and piston engines. For the same engine volume and weight, this engine produces less specific power than a simple-cycle gas turbine, but approximately twice the power of a two-stroke engine and four times the power of a four-stroke engine. The engine has advantages in the 10 kW to 200 kW power range. This paper introduces the geometry and thermodynamic model for the engine, presents typical performance curves, and discusses the relative advantages of this engine over its competitors.
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Kim, Cheonghwan, Sungho Park, Myeongkyu Kim, and Eunsoo Ahn. "Numerical Study on Transfer Port Design for Scavenging Performance in Small Two-stroke Engines." Journal of the Korean Society of Propulsion Engineers 24, no. 6 (December 31, 2020): 28–44. http://dx.doi.org/10.6108/kspe.2020.24.6.028.
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Hooper, Peter R. "Investigation into a stepped-piston engine solution for automotive range-extender vehicles and hybrid electric vehicles to meet future green transportation objectives." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 232, no. 3 (May 30, 2017): 305–17. http://dx.doi.org/10.1177/0954407017698304.
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Securing the objectives for future high-efficiency low-carbon-dioxide vehicles is a key target for automotive manufacturers. This paper considers a high-durability two-stroke cycle engine in terms of performance and computational modelling of the emissions characteristics for automotive range-extender or hybrid electric vehicle power plant application. The engine uses novel segregated pump charging via the application of stepped pistons, and a comparison of the engine characteristics is made with those of a comparable four-stroke cycle engine of similar expected power output (more than 60 kW/l). In the interests of cost minimisation, both engines are limited to parallel two-cylinder in-line configurations with the intention of still being able to achieve acceptably low noise, vibration and harshness characteristics. In order to achieve low engine exhaust emissions, computational modelling of direct injection is considered for the stepped-piston engine. A significant reduction in the nitrogen oxide emissions of between 31% and 55% is observed.
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Anggono, Willyanto, Mitsuhisa Ichiyanagi, Reina Saito, Gabriel J. Gotama, Chris Cornelius, Ryera Kreshna, and Takashi Suzuki. "Airflow Characteristics Investigation of a Diesel Engine for Different Helical Port Openings and Engine Speeds." Journal of Engineering and Technological Sciences 53, no. 3 (June 21, 2021): 210306. http://dx.doi.org/10.5614/j.eng.technol.sci.2021.53.3.6.
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Intake airflow characteristics are essential for the performance of diesel engines. However, previous investigations of these airflow characteristics were mostly performed on two-valve engines despite the difference between the airflow of two-valve and four-valve engines. Therefore, in this study, particle image velocimetry (PIV) investigations were performed on a four-valve diesel engine. The investigations were conducted under different engine speeds and helical port openings using a swirl control valve (SCV). The results suggest that the position of the swirl center does not significantly shift with different engine speeds and helical port openings, as the dynamics of the flow remained closely similar. The trends of the airflow characteristics can be best observed during the compression stroke. A higher engine speed increases the angular velocity of the engine more compared to the increase of the airflow velocity and results in a lower swirl ratio of the flow. On the other hand, a higher engine speed leads to a higher mean velocity and the variation of velocity results in a larger turbulence intensity of the flow. Increasing the helical port opening brings a reduction in the swirl ratio and turbulence intensity as more airflow from the helical port disturbs the airflow from the tangential port.
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Qiao, Yuan, Li Lin, Wei Zhong, and Kaisheng Huang. "Investigation on the Performance Characteristics of 2-Stroke Heavy Fuel Light Aeroengine (2SHFLA) with Different Fuel Injection Systems: Modeling and Comparative Simulation." Energies 13, no. 19 (October 2, 2020): 5136. http://dx.doi.org/10.3390/en13195136.
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Extensive application of small and medium-sized unmanned aerial vehicles (UAVs) have already made the development of corresponding power system a research hotspot nowadays. Two-stroke heavy fuel light aeroengine (2SHFLA) is selected as the research focus in this paper. The working principle of 2SHFLA with different fuel injection systems is elaborated systematically. By dividing the initial prototype engine into several subsystems, the simulation platform is set up with its key model parameters accurately calibrated against the test data. Simulation platforms of the other two types of engines are subsequently constructed based on the pre-calibrated simulation platform of the initial prototype engine. Afterwards, comparative simulation is performed and the corresponding simulation results include: (1) comparison of performance characteristics of the initial prototype engine fueled with regular gasoline/heavy fuel; (2) comprehensive comparison of the performance characteristics of all the three types of engine.
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Adebayo, A., and Omojola Awogbemi. "Effects of Fuel Additives on Performance and Emission Characteristics of Spark Ignition Engine." European Journal of Engineering Research and Science 2, no. 3 (March 23, 2017): 30. http://dx.doi.org/10.24018/ejers.2017.2.3.289.
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This research investigated the effects of addition of ethanol to gasoline with the aim of improving the performance and emission characteristics of Spark Ignition (SI) engine. Four samples of gasoline-ethanol blend were prepared, namely 100% ethanol, 100% gasoline, 95% gasoline + 5% ethanol and 90% gasoline+10% ethanol, and were labeled sample A, B, C and D respectively. Physicochemical analysis was carried out on the four samples while sample B, C, and D were used to run a single cylinder, two stroke, air cooled SI engine to determine the performance characteristics of the engine at four engine speeds of 800rpm, 1000rpm, 1200rpm, and 1400rpm. An exhaust gas analyzer was used to analyze the exhaust emission to determine its constituents at no load. The research concluded that blending gasoline with ethanol not only improved the performance of the engine, it also yielded a friendlier emission. It also solves the problem of sole dependence on petroleum products to run SI engines with its attendant cost and environmental implications.
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He, Yuhai, Peilin Zhou, Liangtao Xie, and Jiyun Zhang. "Design and experimental development of a new electronically controlled cylinder lubrication system for the large two-stroke crosshead diesel engines." International Journal of Engine Research 20, no. 8-9 (January 8, 2019): 986–1000. http://dx.doi.org/10.1177/1468087418824216.
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Accurate, stable and reliable lubrication for the cylinders is very important to ensure the trouble-free operation of the marine diesel engines. A new electronically controlled cylinder lubrication system has been developed to remedy the defects of the conventional mechanical lubrication system. This new system’s design method, composition and implementation are described. The sensitivity tests are conducted on the test bench and the verification tests are also fulfilled on operating vessels. The main performance data are as follows: oil injection pressure about 3.0 MPa, oil injection timing precision 0.1 ms, oil injection duration 15 °CA or less. The oil injection concentrates onto the piston rings pack to ensure the good lubrication and neutralization, and the oil injection frequency is regulated according to engine load, the sulphur content in fuel, total base number of cylinder oil, cylinder liner running-in condition and so on. This results in the cylinder oil consumption rate falling approximately 25% compared with that of the conventional mechanical lubrication system. As a retrofit on vessels in service, the lubrication system has been fitted more than 120 main engines and has a payback period of less than 2 years.
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Li, Bin, and Shou Jun Zhang. "MV “CRYSTAL STAR” Diesel Turbocharger Surge Cause Analysis and Troubleshooting." Applied Mechanics and Materials 672-674 (October 2014): 1562–67. http://dx.doi.org/10.4028/www.scientific.net/amm.672-674.1562.
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Currently shipping costs are increasing sharply due to the rising oil prices. In order to reduce shipping costs, most low-speed two-stroke diesel engines run at low speeds to reduce fuel oil consumption, and this measure might result turbocharger surge. For modern marine diesel engines, the exhaust gas turbochargers are becoming more and more important; their working conditions have a direct impact on the performance of diesel engines, consequently affecting the operation of the ship. Surge will fail a turbocharger to achieve the supercharging ratio, damage the turbocharger components and even lead to a damage accident of the whole turbocharger. Therefore, a good understanding of the reasons for marine diesel engine turbocharger surge will help to prevent and eliminate turbocharger surge in operation. This paper is to make an analysis on the special surge mechanism occurred to the turbocharger on MV "Crystal Star", and propose some appropriate supervisory and preventive measures against the problem.
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Trenc, F., F. Bizjan, and A. Hribernik. "Influence of the Exhaust System on Performance of a 4-Cylinder Supercharged Engine." Journal of Engineering for Gas Turbines and Power 120, no. 4 (October 1, 1998): 855–60. http://dx.doi.org/10.1115/1.2818478.
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Twin entry radial turbines are mostly used to drive compressors of small and medium size 6-cylinder diesel engines where the available energy of the undisturbed exhaust pulses can be efficiently used to drive the turbine of a turbocharger. Three selected cylinders feed two separated manifold branches and two turbine inlets and prevent negative interaction of pressure waves and its influence on the scavenging process of the individual cylinders. In the case of a four-stroke, 4-cylinder engine, two selected cylinders, directed by the firing order, can be connected to one (of the two) separated manifold branches that feeds one turbine entry. Good utilization of the pressure pulse energy, together with typically longer periods of reduced exhaust flow can lead to good overall efficiency of the “two-pulse” system. Sometimes this system can be superior to the single manifold system with four cylinders connected to one singleentry turbine. The paper describes advantages and disadvantages of the above described exhaust systems applied to a turbocharged and aftercooled 4-cylinder Diesel engine. Comparisons supported by the analyses of the numerical and experimental results are also given in the presented paper.
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Konyukov, Vyacheslav Leontievich. "Analysis of operating characteristics of 7S50MC diesel engine under direct air management." Vestnik of Astrakhan State Technical University. Series: Marine engineering and technologies 2020, no. 1 (February 17, 2020): 72–82. http://dx.doi.org/10.24143/2073-1574-2020-1-72-82.
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The paper provides a theoretical analysis of the operational performance of a marine two-stroke diesel engine in a wide range of modes, operating on a helical characteristic. Reducing the diesel load causes a decrease in the coefficient of excess air for combustion, which is characteristic of two-stroke diesel engines with a relatively high boost pressure. To control the air flow rate, it is proposed to use an adjustable nozzle apparatus as part of a turbine of a turbocharger unit. Changing the angle of the blades of an adjustable nozzle apparatus by turning them, an impact was made on the characteristics of the turbine, compressor and, accordingly, on the operational performance of the diesel engine. With decreasing the angle of the blades of the nozzle apparatus, the effective passage area of the turbine of the turbo-charging unit decreases. This causes an increase in gas pressure in front of the turbine and, consequently, an increase in the power of the turbine and compressor. This increases the boost pressure and the available work of the air charge of the cylinder. The engine operates with a large excess air ratio for combustion and increased efficiency. There are presented the results of a comparative analysis of diesel performance caused by rotation of the blades of an adjustable nozzle apparatus and the initial version, in which the angle of the blades of the nozzle apparatus remained unchanged. The angle of rotation of the blades was selected in such a way as to ensure unchanged the coefficient of excess air for combustion in all the studied diesel operation modes. The studies showed a considerable improvement in the performance of a two-stroke diesel engine at shared load modes when using an adjustable nozzle apparatus of a turbo-charging unit.
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Scappin, Fabio, Sigurður H. Stefansson, Fredrik Haglind, Anders Andreasen, and Ulrik Larsen. "Validation of a zero-dimensional model for prediction of NOx and engine performance for electronically controlled marine two-stroke diesel engines." Applied Thermal Engineering 37 (May 2012): 344–52. http://dx.doi.org/10.1016/j.applthermaleng.2011.11.047.
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Liang, Xingyu, Xinyi Cao, Fei Zhang, Enxing Zhang, Peijian Yang, and Hanzhengnan Yu. "Comparison of the Performance of Different Mechanisms on Soot Generation of Low-Speed Two-Stroke Marine Engines." Energy Procedia 158 (February 2019): 4572–78. http://dx.doi.org/10.1016/j.egypro.2019.01.751.
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Liu, Rui, Xiaoping Su, Xiaodong Miao, Guang Yang, Xuefei Dong, Yongsheng Liang, and Taiqi Huang. "Combustion characteristics of a two-stroke spark ignition UAV engine fuelled with gasoline and kerosene (RP-3)." Aircraft Engineering and Aerospace Technology 91, no. 1 (January 7, 2018): 163–70. http://dx.doi.org/10.1108/aeat-03-2018-0112.
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Purpose The purpose of this paper is to compare the combustion characteristics, including the combustion pressure, heat release rate (HRR), coefficient of variation (COV) of indicated mean effective pressure (IMEP), flame development period and combustion duration, of aviation kerosene fuel, namely, rocket propellant 3 (RP-3), and gasoline on a two-stoke spark ignition engine. Design/methodology/approach This paper is an experimental investigation using a bench test to reflect the combustion performance of two-stroke spark ignition unmanned aerial vehicle (UAV) engine on gasoline and RP-3 fuel. Findings Under low load conditions, the combustion performance and HRR of burning RP-3 fuel were shown to be worse than those of gasoline. Under high load conditions, the average IMEP and the COV of IMEP of burning RP-3 fuel were close to those of gasoline. The difference in the flame development period between gasoline and RP-3 fuel was similar. Practical implications Gasoline fuel has a low flash point, high-saturated vapour pressure and relatively high volatility and is a potential hazard near a naked flame at room temperature, which can create significant security risks for its storage, transport and use. Adopting a low volatility single RP-3 fuel of covering all vehicles and equipment to minimize the number of different devices with the use of a various fuels and improve the application safeties. Originality/value Most two-stroke spark ignition UAV engines continue to combust gasoline. A kerosene-based fuel operation can be applied to achieve a single-fuel policy.
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Каримова, Д. М., А. Ф. Хайдаров, and Г. Ю. Климентова. "STUDY OF THE COMPATIBILITY OF S-CONTAINING PHENOLIC ANTIOXIDANT ADDITIVES AND OILS FOR TWO-STROKE ENGINES." Южно-Сибирский научный вестник, no. 2(36) (April 30, 2021): 94–97. http://dx.doi.org/10.25699/sssb.2021.36.2.010.
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Двухтактные двигатели за счет простоты своей конструкции, небольшого количества деталей и компактности пользуются большим спросом во многих отраслях, преимущественно для садовой техники и мотоциклов. В таких двигателях используется бензо-масляная смесь для создания масляной пленки, обеспечения достаточной смазки трущихся деталей и защиты их от коррозии. К современному моторному маслу для двухтактного двигателя существует ряд требований: полное выгорание без образования кокса, золы, отложений, хорошее растворение и перемешивание с топливом, противоизносные, антикоррозионные, смазывающие свойства при высоких температурах. Одновременного выполнения всех требований достичь представляется проблематично. Производители моторных масел используют различные присадки, улучшающие функциональные свойства масел. Известно, что содержание присадки в масле может достигать 3%. В настоящей статье рассматривается возможность использования S-содержащих пространственно-затрудненных фенолов как многофункциональных присадок. Эти вещества обладают высокой антиокислительной активностью за счет своего строения, благодаря которому замедляются процессы окисления. В качестве объекта сравнения были взяты показатели базовых масел, полученные при исследовании низкотемпературных свойств, кинематической вязкости и определении индекса вязкости. Низкотемпературные свойства присадок в смеси с маслом показали возможность использования этих веществ и в качестве пеногасящей присадки. Результаты исследования кинематической вязкости масел с присадками показали небольшое увеличение адсорбционной способности масла на деталях двигателя. Использование S-содержащих пространственно-затрудненных фенолов в составе смазывающей композиции представляется целесообразным. По исследуемым показателям можно видеть, что данные соединения совместимы с базовыми маслами. Two-stroke engines, due to their simplicity of design, a small number of parts and compactness, are in great demand in many industries, mainly for garden equipment and motorcycles. These engines use a petrol-oil mixture to create an oil film, ensure sufficient lubrication of rubbing parts and protect them from corrosion. There are a number of requirements for a modern engine oil for a two-stroke engine: complete burnout without the formation of coke, ash, deposits, good dissolution and mixing with fuel, antiwear, anti-corrosion, lubricating properties at high temperatures. It seems problematic to achieve the simultaneous fulfillment of all requirements. Motor oil manufacturers use a variety of additives to improve the performance of oils. It is known that the additive content in oil can be up to 3%. This article discusses the possibility of using S-containing sterically hindered phenols as multifunctional additives. These substances have high antioxidant activity due to their structure, due to which oxidation processes are slowed down. As an object of comparison, the indicators of base oils were taken, obtained in the study of low-temperature properties, kinematic viscosity and determination of the viscosity index. The low-temperature properties of the additives mixed with oil have shown the possibility of using these substances as a defoaming additive. The results of studying the kinematic viscosity of oils with additives showed a slight increase in the adsorption capacity of the oil on engine parts. The use of S-containing sterically hindered phenols in the composition of the lubricating composition seems to be expedient. According to the studied indicators, it can be seen that these compounds are compatible with base oils.
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Ciampolini, Marco, Simone Bigalli, Francesco Balduzzi, Alessandro Bianchini, Luca Romani, and Giovanni Ferrara. "CFD Analysis of the Fuel–Air Mixture Formation Process in Passive Prechambers for Use in a High-Pressure Direct Injection (HPDI) Two-Stroke Engine." Energies 13, no. 11 (June 3, 2020): 2846. http://dx.doi.org/10.3390/en13112846.
Full textAbstract:
The research on two-stroke engines has been focused lately on the development of direct injection systems for reducing the emissions of hydrocarbons by minimizing the fuel short-circuiting. Low temperature combustion (LTC) may be the next step to further improve emissions and fuel consumption; however, LTC requires unconventional ignition systems. Jet ignition, i.e., the use of prechambers to accelerate the combustion process, turned out to be an effective way to perform LTC. The present work aims at proving the feasibility of adopting passive prechambers in a high-pressure, direct injection, two-stroke engine through non-reactive computational fluid dynamics analyses. The goal of the analysis is the evaluation of the prechamber performance in terms of both scavenging efficiency of burnt gases and fuel/air mixture formation inside the prechamber volume itself, in order to guarantee the mixture ignitability. Two prechamber geometries, featuring different aspect ratios and orifice numbers, were investigated. The analyses were replicated for two different locations of the injection and for three operating conditions of the engine in terms of revolution speed and load. Upon examination of the results, the effectiveness of both prechambers was found to be strongly dependent on the injection setup.
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Ganapathy, Thirunavukkarasu, Parkash Gakkhar, and Krishnan Murugesan. "An analytical and experimental study of performance on jatropha biodiesel engine." Thermal Science 13, no. 3 (2009): 69–82. http://dx.doi.org/10.2298/tsci0903069g.
Full textAbstract:
Biodiesel plays a major role as one of the alternative fuel options in direct injection diesel engines for more than a decade. Though many feed stocks are employed for making biodiesel worldwide, biodiesel derived from domestically available non-edible feed stocks such as Jatropha curcas L. is the most promising alternative engine fuel option especially in developing countries. Since experimental analysis of the engine is pricey as well as more time consuming and laborious, a theoretical thermodynamic model is necessary to analyze the performance characteristics of jatropha biodiesel fueled diesel engine. There were many experimental studies of jatropha biodiesel fueled diesel engine reported in the literature, yet theoretical study of this biodiesel run diesel engine is scarce. This work presents a theoretical thermodynamic study of single cylinder four stroke direct injection diesel engine fueled with biodiesel derived from jatropha oil. The two zone thermodynamic model developed in the present study computes the in-cylinder pressure and temperature histories in addition to various performance parameters. The results of the model are validated with experimental values for a reasonable agreement. The variation of cylinder pressure with crank angle for various models are also compared and presented. The effects of injection timing, relative air fuel ratio and compression ratio on the engine performance characteristics for diesel and jatropha biodiesel fuels are then investigated and presented in the paper.