Journal articles: 'Otto-cycle engine'

1

Sasaki, Senichi. "Dual-Fuel Engine, Otto Cycle and Diesel Cycle." Journal of The Japan Institute of Marine Engineering 44, no. 6 (2009): 978. http://dx.doi.org/10.5988/jime.44.978.

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Diskin, David, and Leonid Tartakovsky. "Efficiency at Maximum Power of the Low-Dissipation Hybrid Electrochemical–Otto Cycle." Energies 13, no. 15 (August 1, 2020): 3961. http://dx.doi.org/10.3390/en13153961.

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A novel analytical method was developed for analysis of efficiency at maximum power of a hybrid cycle combining electrochemical and Otto engines. The analysis is based on the low-dissipation model, which relates energy dissipation with energy transfer rate. Efficiency at maximum power of a hybrid engine operating between two reservoirs of chemical potentials is evaluated. The engine is composed of an electrochemical device that transforms chemical potential to electrical work of an Otto engine that uses the heat generated in the electrochemical device and its exhaust effluent for mechanical work production. The results show that efficiency at maximum power of the hybrid cycle is identical to the efficiency at maximum power of an electrochemical engine alone; however, the power is the product of the electrochemical engine power and the compression ratio of the Otto engine. Partial mass transition by the electrochemical device from the high to the low chemical potential is also examined. In the latter case, heat is generated both in the electrochemical device and the Otto engine, and the efficiency at maximum power is a function of the compression ratio. An analysis performed using the developed method shows, for the first time, that, in terms of a maximal power, at some conditions, Otto cycle can provide better performance that the hybrid cycle. On the other hand, an efficiency comparison at maximum power with the separate Otto-cycle and chemical engine results in some advantages of the hybrid cycle.

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Oh, Jungmo, Kichol Noh, and Changhee Lee. "A Theoretical Study on the Thermodynamic Cycle of Concept Engine with Miller Cycle." Processes 9, no. 6 (June 16, 2021): 1051. http://dx.doi.org/10.3390/pr9061051.

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The Atkinson cycle, where expansion ratio is higher than the compression ratio, is one of the methods used to improve thermal efficiency of engines. Miller improved the Atkinson cycle by controlling the intake- or exhaust-valve closing timing, a technique which is called the Miller cycle. The Otto–Miller cycle can improve thermal efficiency and reduce NOx emission by reducing compression work; however, it must compensate for the compression pressure and maintain the intake air mass through an effective compression ratio or turbocharge. Hence, we performed thermodynamic cycle analysis with changes in the intake-valve closing timing for the Otto–Miller cycle and evaluated the engine performance and Miller timing through the resulting problems and solutions. When only the compression ratio was compensated, the theoretical thermal efficiency of the Otto–Miller cycle improved by approximately 18.8% compared to that of the Otto cycle. In terms of thermal efficiency, it is more advantageous to compensate only the compression ratio; however, when considering the output of the engine, it is advantageous to also compensate the boost pressure to maintain the intake air mass flow rate.

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Pandit, Tanmoy, Pritam Chattopadhyay, and Goutam Paul. "Non-commutative space engine: A boost to thermodynamic processes." Modern Physics Letters A 36, no. 24 (August 10, 2021): 2150174. http://dx.doi.org/10.1142/s0217732321501741.

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We introduce quantum heat engines that perform quantum Otto cycle and the quantum Stirling cycle by using a coupled pair of harmonic oscillator as its working substance. In the quantum regime, different working medium is considered for the analysis of the engine models to boost the efficiency of the cycles. In this work, we present Otto and Stirling cycle in the quantum realm where the phase space is non-commutative in nature. By using the notion of quantum thermodynamics, we develop the thermodynamic variables in non-commutative phase space. We encounter a catalytic effect (boost) on the efficiency of the engine in non-commutative space (i.e. we encounter that the Stirling cycle reaches near to the efficiency of the ideal cycle) when compared with the commutative space. Moreover, we obtained a notion that the working medium is much more effective for the analysis of the Stirling cycle than that of the Otto cycle.

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Schiffgens, H. J., H. Endres, H. Wackertapp, and E. Schrey. "Concepts for the Adaptation of SI Gas Engines to Changing Methane Number." Journal of Engineering for Gas Turbines and Power 116, no. 4 (October 1, 1994): 733–39. http://dx.doi.org/10.1115/1.2906880.

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In a joint project of FEV Motorentechnik and Ruhrgas AG, the design of stoichiometric and lean-burn Otto engines was optimized by selective modifications to the design and operating parameters to accommodate changing methane numbers (LPG addition to CNG). Of particular importance was knock-free engine operation at a low NOx output to meet the requirements of the German Clean Air Code while concurrently achieving both high efficiencies and mean effective pressures. Based upon the results obtained, concepts for the control of Otto-cycle gas engines to accept changing methane numbers were developed. The newly developed gas engine control device allows these concepts to meet the requirement of the German Clean Air Code with economically viable conditions while preventing engine knock. Furthermore, the test results show that dedicated Otto-cycle gas engines can meet the most stringent emission limits for commercial vehicles while maintaining high efficiencies.

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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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7

Naaktgeboren, Christian. "An air-standard finite-time heat addition Otto engine model." International Journal of Mechanical Engineering Education 45, no. 2 (February 8, 2017): 103–19. http://dx.doi.org/10.1177/0306419016689447.

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A classical thermodynamic model for spark-ignited internal combustion engine simulation in which the heat addition process that takes a finite amount of time to complete is presented along with an illustrative parameter sensibility case study. The model accounts for all air-standard Otto cycle parameters, as well as crank-connecting rod mechanism, ignition timing, engine operating speed, and cumulative heat release history parameters. The model is particularly suitable for engineering undergraduate education, as it preserves most of the air-standard assumptions, while being able to reproduce real engine traits, such as the decay of maximum pressure, power, and thermal efficiency at higher engine operating speeds. In terms of complexity, the resulting finite-time heat addition Otto cycle sits between the classical air-standard Otto cycle and the more involved air–fuel Otto cycle, that are usually introduced on more advanced mechanical engineering courses, and allows students to perform engine parameter sensibility studies using only classical, single phase, pure substance, undergraduate engineering thermodynamics.

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8

Chicurel, R. "A modified Otto cycle engine for fuel economy." Applied Energy 38, no. 2 (January 1991): 105–16. http://dx.doi.org/10.1016/0306-2619(91)90069-a.

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Willi, M. L., and B. G. Richards. "Design and Development of a Direct Injected, Glow Plug Ignition-Assisted, Natural Gas Engine." Journal of Engineering for Gas Turbines and Power 117, no. 4 (October 1, 1995): 799–803. http://dx.doi.org/10.1115/1.2815467.

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Conventional (Otto cycle) natural gas engines are limited in power and thermal efficiency relative to a diesel engine due to detonation and the need to run a nearly stoichiometric air/fuel ratio. Technology is under development to burn natural gas in a direct-injected diesel cycle that is not prone to detonation or air/fuel ratio control limitations. Direct-injected gas (DIG) technology will allow natural gas engines to match the power and thermal efficiency of the equivalent diesel-fueled engine. Laboratory development now under way is targeted for field experimental evaluation of a DIG 3516 engine in a 1500 kW road switcher locomotive. This paper will describe DIG 3516 engine component design and single and multicylinder performance development.

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10

Sharke, Paul. "Otto or Not, Here it Comes." Mechanical Engineering 122, no. 06 (June 1, 2000): 62–66. http://dx.doi.org/10.1115/1.2000-jun-4.

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This article highlights the new ignition schemes for Otto cycle engines that seem to be bound for extinction. Ever since Nicolaus Otto demonstrated the first working four-stroke engine in 1876, engineers have been struggling to come up with ways to sidestep a fundamental limitation of an otherwise stellar design. The reciprocating engine is capable of generating high pressure with reliable sealing, but the volume swept out by the piston has had to remain fixed. Small engines use less internal reciprocating mass than large ones, so the energy to overcome friction decreases as size drops. Small engines are lighter than big ones, too. By recirculating exhaust gases back into the combustion chamber, however, Mitsubishi uses the exhaust to reduce NOx. Because the air-to-fuel ratio is so high, the exhaust gases, which normally hinder combustion, can be as much as 70 percent of the cylinder volume. At the same time, Mitsubishi uses a lean NOx catalytic converter.

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11

Gonca, Guven. "Comparative performance analyses of irreversible OMCE (Otto Miller cycle engine)-DiMCE (Diesel miller cycle engine)-DMCE (Dual Miller cycle engine)." Energy 109 (August 2016): 152–59. http://dx.doi.org/10.1016/j.energy.2016.04.049.

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12

Peña, Francisco J., Oscar Negrete, Natalia Cortés, and Patricio Vargas. "Otto Engine: Classical and Quantum Approach." Entropy 22, no. 7 (July 9, 2020): 755. http://dx.doi.org/10.3390/e22070755.

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In this paper, we analyze the total work extracted and the efficiency of the magnetic Otto cycle in its classic and quantum versions. As a general result, we found that the work and efficiency of the classical engine is always greater than or equal to its quantum counterpart, independent of the working substance. In the classical case, this is due to the fact that the working substance is always in thermodynamic equilibrium at each point of the cycle, maximizing the energy extracted in the adiabatic paths. We apply this analysis to the case of a two-level system, finding that the work and efficiency in both the Otto’s quantum and classical cycles are identical, regardless of the working substance, and we obtain similar results for a multilevel system where a linear relationship between the spectrum of energies of the working substance and the external magnetic field is fulfilled. Finally, we show an example of a three-level system in which we compare two zones in the entropy diagram as a function of temperature and magnetic field to find which is the most efficient region when performing a thermodynamic cycle. This work provides a practical way to look for temperature and magnetic field zones in the entropy diagram that can maximize the power extracted from an Otto magnetic engine.

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13

Zhao, Yingru, Bihong Lin, and Jincan Chen. "Optimum Criteria on the Important Parameters of an Irreversible Otto Heat Engine With the Temperature-Dependent Heat Capacities of the Working Fluid." Journal of Energy Resources Technology 129, no. 4 (April 26, 2007): 348–54. http://dx.doi.org/10.1115/1.2794770.

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An irreversible cycle model of the Otto heat engine is established, in which the temperature-dependent heat capacities of the working fluid, the irreversibilities resulting from the nonisentropic compression and expansion processes, and heat leak losses through the cylinder wall are taken into account. The adiabatic equation of ideal gases with the temperature-dependent heat capacity is strictly deduced without using the additional approximation condition in the relevant literature and used to analyze the performance of the Otto heat engine. Expressions for the work output and efficiency of the cycle are derived by introducing the compression ratio of two isochoric processes. The performance characteristic curves of the Otto heat engine are presented for a set of given parameters. The optimum criteria of some important parameters such as the work output, efficiency, compression ratio, and temperatures of the working fluid are given. Moreover, the influence of the compression and expansion efficiencies, the variable heat capacities, the heat leak, and other parameters on the performance of the cycle is discussed in detail. The results obtained are novel and general, from which some relevant conclusions in literature may be directly derived. This work may provide a significant guidance for the performance improvement and optimal design of the Otto heat engine.

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Johal, Ramandeep S., and Venu Mehta. "Quantum Heat Engines with Complex Working Media, Complete Otto Cycles and Heuristics." Entropy 23, no. 9 (September 1, 2021): 1149. http://dx.doi.org/10.3390/e23091149.

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Quantum thermal machines make use of non-classical thermodynamic resources, one of which include interactions between elements of the quantum working medium. In this paper, we examine the performance of a quasi-static quantum Otto engine based on two spins of arbitrary magnitudes subject to an external magnetic field and coupled via an isotropic Heisenberg exchange interaction. It has been shown earlier that the said interaction provides an enhancement of cycle efficiency, with an upper bound that is tighter than the Carnot efficiency. However, the necessary conditions governing engine performance and the relevant upper bound for efficiency are unknown for the general case of arbitrary spin magnitudes. By analyzing extreme case scenarios, we formulate heuristics to infer the necessary conditions for an engine with uncoupled as well as coupled spin model. These conditions lead us to a connection between performance of quantum heat engines and the notion of majorization. Furthermore, the study of complete Otto cycles inherent in the average cycle also yields interesting insights into the average performance.

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15

Dehelean, Nicolae Mircea, and Liana Maria Dehelean. "A Mechanism for Self-Starting Thermal Engine." Applied Mechanics and Materials 162 (March 2012): 29–36. http://dx.doi.org/10.4028/www.scientific.net/amm.162.29.

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The conventional engine cannot start alone. The engine needs a special device to turn it on. This device is usually an electric motor that is called starter. Any other engine that uses another working cycle then Otto cycle or Diesel cycle could accede to a self-starting ability. The paper tries to use ancient ideas in order to develop a true thermal engine able to use solar and other renewable energy. This unconventional engine inherits some ideas from the perpetual motion machine solutions.

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Espinosa, Luis F., and Petros Lappas. "Mathematical Modelling Comparison of a Reciprocating, a Szorenyi Rotary, and a Wankel Rotary Engine." Nonlinear Engineering 8, no. 1 (January 28, 2019): 389–96. http://dx.doi.org/10.1515/nleng-2017-0082.

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Abstract This paper provides an explanation of the geometry, design, and operational principles for the three engines; having special emphasis in the Szorenyi rotary engine which has a deforming rhombus revolving inside a mathematically defined stator. A basic ideal mathematical simulation of those engines were performed, assuming the Otto cycle for the three engines. Also, it assumes the volumetric efficiency of 100%, a wide-open throttle (WOT), no knock nor any mechanical or thermal losses. This simulation focuses on how the fuel burns during combustion, creating pressure and thus, net work. A comparison in pressure traces and cycle performance is made. The study concludes analysing and comparing the ignition advance; finding the best advance for each engine thus the net work between the three engines during one working cycle. Finally, this paper analyses how the different volume change ratio for the combustion chamber of the Szorenyi, Wankel and the reciprocating engine have an effect in the pressure, net work and thermal efficiency generated inside the chamber during combustion for every working cycle.

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17

Ebrahim, Rahim. "Performance Analysis of an Otto Engine with Ethanol and Gasoline Fuels." Applied Mechanics and Materials 110-116 (October 2011): 267–72. http://dx.doi.org/10.4028/www.scientific.net/amm.110-116.267.

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Energy conservation and its efficient use are nowadays a major issue. The evident reduction in oil reserves combined with the increase in its price, as well as the need for ‘cleaner’ fuels, have led in the past years to an increasing interest and research in the field of alternative fuels for spark ignition engines propulsion. Also, there are interesting to increase the technical focus on conventional cycles for making them more optimum in terms of performance. In this study, a comparative performance analysis and optimisation have been performed for irreversible Otto cycle with ethanol, methanol and gasoline fuels. The results show that the maximum power output, the working range of the cycle, the optimal power output corresponding to maximum thermal efficiency, the optimal thermal efficiency corresponding to maximum power output increase, the compression ratio at the maximum power output and the compression ratio at the maximum thermal efficiency when ethanol-engine operation is changed to gasoline-engine operation. The results obtained in this work can help us to understand how the power output and thermal efficiency are influenced by ethanol and gasoline fuels in an Otto engine.

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18

Kossov, E. E., V. V. Asabin, A. G. Silyuta, A. N. Zhuravlev, and L. E. Kossova. "Some aspects of the use of natural gas motor fuel in diesel locomotives." VNIIZHT Scientific Journal 79, no. 5 (November 10, 2020): 301–9. http://dx.doi.org/10.21780/2223-9731-2020-79-5-301-309.

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Due to the increase in the cost of diesel fuel, much attention is paid to the use of alternative types of fuel on diesel locomotives. Variants of using fuel obtained from coal, plants, gas fields and hydrogen are considered. Natural gas is the cheapest and most accessible today. The use of specially designed gas-piston engines on diesel locomotives, operating when the gas-air mixture is ignited from an external source, is the most attractive option. However, this approach has certain disadvantages:• it is necessary to create a new engine, since the modernization of existing engines requires serious structural changes;• gas piston engine operates essentially according to the Otto cycle and has lower efficiency and power indicators as compared to a diesel engine;• when modernizing existing diesel locomotives, switching to the Otto cycle excludes the possibility of using diesel fuel.Conversion of diesel locomotives to gas fuel must be carried out using the gas-diesel cycle. This approach is most acceptable for the modernization of diesel locomotives of the existing fleet, since it preserves the thermal performance of the engine and makes it possible to transfer diesel locomotives back to operation on diesel fuel. The main obstacle to the transfer of diesel locomotives to the gas-diesel cycle is the low degree of replacement of diesel fuel with gas. This circumstance is determined by the significant difficulties in ensuring the operation of the engine in the gas-diesel cycle at low loads and idling. It is necessary to ensure a stable supply of ignition fuel in these modes and guaranteed ignition of the gas-air mixture from it. The solution to this problem is ensured by maintaining a given stoichiometric ratio in the gas-air mixture and a temperature sufficient to ignite the ignition portion of the fuel.The main way to regulate the stoichiometric ratio is to reduce the amount of air entering the cylinders by throttling it at the engine inlet. This article discusses the methodology for calculating the performance of the engine when throttling the air inlet.

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Georgiou, Demos P., Nikolaos G. Theodoropoulos, and Kypros F. Milidonis. "Ideal Thermodynamic Cycle Analysis for the Meletis-Georgiou Vane Rotary Engine Concept." Journal of Thermodynamics 2010 (July 5, 2010): 1–9. http://dx.doi.org/10.1155/2010/130692.

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The Meletis-Georgiou is a patented Vane Rotary Engine concept that incorporates separate compression-expansion chambers and a modified Otto (or Miller) cycle, characterized by (Exhaust) Gas Recirculation at elevated pressures. This is implemented by transferring part of the expansion chamber volume into the compression one through the coordinated action of two vane diaphragms. This results into a very high gas temperature at the end of the compression, something that permits autoignition under all conditions for a Homogeneous Compression Ignition (HCCI) version of the engine. The relevant parametric analysis of the ideal cycle shows that the new cycle gives ideal thermal efficiencies of the order of 60% to 70% under conditions corresponding to homogeneous compression engines but at reduced pressures when compared against the corresponding Miller cycle.

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20

Huang, Zhao-Ming, Kai Shen, Li Wang, Wei-Guo Chen, and Jin-Yuan Pan. "Experimental study on the effects of the Miller cycle on the performance and emissions of a downsized turbocharged gasoline direct injection engine." Advances in Mechanical Engineering 12, no. 5 (May 2020): 168781402091872. http://dx.doi.org/10.1177/1687814020918720.

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The Miller cycle has been proven to be an effective way to improve the thermal efficiency for gasoline engines. However, it may show insufficient power performance at certain loads. In this study, the objective is to exploit the advantages of the Miller-cycle engines over the original Otto-cycle engines. Therefore, a new camshaft profile with early intake valve closure was devised, and two various pistons were redesigned to obtain higher compression ratio 11.2 and 12.1, based on the original engine with compression ratio 10. Then, a detailed comparative investigation of the effects of Miller cycle combined with higher compression ratio on the performance and emission of a turbocharged gasoline direct injection engine has been experimentally carried out based on the engine bench at full and partial loads, compared to the original engine. The results show that, at full load, for a turbocharged gasoline direct injection engine utilizing the Miller cycle, partial maximum power is compromised about 1.5% while fuel consumption shows a strong correlation with engine speed. At partial load, since the Miller effect can well reduce the pumping mean effective pressure, thus improves the fuel economy effectively. In addition, the suppression of the in-cylinder combustion temperature induced by the lower effective compression ratio contributes to the reduction of nitrogen oxide emission greatly. However, the total hydrocarbon emission increases slightly. Therefore, a combination of the Miller cycle and highly boosted turbocharger shows great potential in further improvement of fuel economy and anti-knock performance for downsized gasoline direct injection engines.

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Nimsiriwangso, Atip, Paul Barnes, Omid Doustdar, Miroslaw L. Wyszynski, Gasim Mohamed, Maisara Mohyeldin, and Miroslaw Kowalski. "6-Stroke Engine: Thermodynamic Modelling and Design for Testing." Journal of KONES 26, no. 2 (June 1, 2019): 93–106. http://dx.doi.org/10.2478/kones-2019-0037.

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Abstract In the study AVL BOOST™ is used to perform a thermodynamic simulation of a six-stroke engine, being built by a research team based in Saudi Arabia. The six-stroke cycle consists of a standard four-stroke Otto Cycle followed by a heat recovering steam expansion cycle. Water is injected into the hot combustion chamber towards the end of the Otto expansion stroke producing steam, which is used to perform work on a piston. This process produces power using waste heat and therefore increases the overall efficiency of the engine. The Robin EY28D engine, which is a single cylinder, four-stroke, gasoline engine was used for this simulation study. The engine was modelled and converted into six-stroke engine in AVL BOOST. The results show that six-stroke engine is more efficient than four-stroke engine. In six-stroke engine, the engine power is increased by 33.1% and brake specific fuel consumption (BSFC) is decreased by approximately 16%. Where emissions are concerned, Nitrogen Oxide (NOx) emission from six-stroke engine is reduced by 80%, while the Hydrocarbon (HC) emission increases by 85% compared with the original 4-stroke. Moreover, the most efficient camshaft was found and designed according to the most efficient valve profile for this engine, which is combination of 60CA° of valve duration and 10 mm of valve lifting.

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Cullen, Barry, and Jim McGovern. "Energy system feasibility study of an Otto cycle/Stirling cycle hybrid automotive engine." Energy 35, no. 2 (February 2010): 1017–23. http://dx.doi.org/10.1016/j.energy.2009.06.025.

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23

Vorobyov, S. A., and P. A. Razumov. "Algorithm for using hydrogen fuel in wheeled vehicles." Вестник гражданских инженеров 17, no. 3 (2020): 168–72. http://dx.doi.org/10.23968/1999-5571-2020-17-3-168-172.

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The use of hydrogen as fuel in wheeled vehicles with an internal combustion engine is considered, and an algorithm for its effective use is developed. This algorithm will minimize the time and cost of re-equipping the power system to obtain an environmental and economic effect on vehicles equipped with gasoline or gas internal combustion engines operating on the Otto cycle with various power systems.

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24

Gambino, M., R. Cericola, P. Corbo, and S. Iannaccone. "Carbonyl Compounds and PAH Emissions From CNG Heavy-Duty Engine." Journal of Engineering for Gas Turbines and Power 115, no. 4 (October 1, 1993): 747–49. http://dx.doi.org/10.1115/1.2906769.

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Previous works carried out in Istituto Motori laboratories have shown that natural gas is a suitable fuel for general means of transportation. This is because of its favorable effects on engine performance and pollutant emissions. The natural gas fueled engine provided the same performance as the diesel engine, met R49 emission standards, and showed very low smoke levels. On the other hand, it is well known that internal combustion engines emit some components that are harmful for human health, such as carbonyl compounds and polycyclic aromatic hydrocarbons (PAH). This paper shows the results of carbonyl compounds and PAH emissions analysis for a heavy-duty Otto cycle engine fueled with natural gas. The engine was tested using the R49 cycle that is used to measure the regulated emissions. The test analysis has been compared with an analysis of a diesel engine, tested under the same conditions. Total PAH emissions from the CNG engine were about three orders of magnitude lower than from the diesel engine. Formaldehyde emission from the CNG engine was about ten times as much as from the diesel engine, while emissions of other carbonyl compounds were comparable.

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Hasanpour Omam, Sadegh. "Exhaust waste energy recovery using Otto-ATEG-Stirling engine combined cycle." Applied Thermal Engineering 183 (January 2021): 116210. http://dx.doi.org/10.1016/j.applthermaleng.2020.116210.

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Wu, Chih, Paul V. Puzinauskas, and Jung S. Tsai. "Performance analysis and optimization of a supercharged Miller cycle Otto engine." Applied Thermal Engineering 23, no. 5 (April 2003): 511–21. http://dx.doi.org/10.1016/s1359-4311(02)00239-9.

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Bertinatto, Rovian, Leandro Friedrich, Reinaldo Aparecido Bariccatti, Samuel Nelson Melegari de Souza, Flavio Gurgacz, and Felix Augusto Pazuch. "Analysis of lubricant oil contamination and degradation and wear of a biogas-fed otto cycle engine." Acta Scientiarum. Technology 39, no. 4 (September 15, 2017): 409. http://dx.doi.org/10.4025/actascitechnol.v39i4.29458.

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The increasing deployment of biodigesters for the treatment of waste on farms and the use of the biogas generated in the production of energy have highlighted the need for knowing the influence of this fuel on internal combustion engines. This study aimed to analyze the influence of filtrated biogas on lubricant oil contamination and degradation, as well as on engine wear and corrosion. Lubricant oil samples were collected every 75 engine operating hours (EOH) and then correlated between each other and with a sample of new oil, determining the elements present in the biogas that contribute to lubricant oil contamination and degradation, as well as lubricant oil performance in the course of EOH and engine wear. The results demonstrate that hydrogen sulfide affects the performance of the lubricant oil and engine wear. Among the metals, we observed that the copper concentration exceeded the maximum limit recommended in the literature. As for the additives, the variation in concentrations of magnesium impacted on lubricant performance. By monitoring lubricant oil quality were able to extend the engine oil change interval of this study by 50%, what resulted in a savings of 33.3% in the cost of lubricant per hour worked.

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Ebrahim, Rahim, Mahmoud Reza Tadayon, Farshad Tahmasebi Gandomkari, and Kamyar Mahbobian. "Effect of Ethanol-Air Equivalence Ratio on Performance of an Endoreversible Otto Engine." Applied Mechanics and Materials 110-116 (October 2011): 273–77. http://dx.doi.org/10.4028/www.scientific.net/amm.110-116.273.

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Today, the world community is looking for fuel efficient and environmentally viable alternatives for many of the traditional energy conversion approaches. This development has further worked to increase the technical focus on conventional cycles for making them more optimum in terms of performance. Hence, the objective of this paper is to study the effect of ethanol-air equivalence ratio on the power output and the indicated thermal efficiency of an air standard Otto cycle. Optimization of the cycle has been performed for power output as well as for thermal efficiency with respect to compression ratio. The results show that the maximum power output, the optimal compression ratio corresponding to maximum power output point, the optimal compression ratio corresponding to maximum thermal efficiency point and the working range of the cycle first increase and then decrease as the equivalence ratio increases. The result obtained herein provides a guide to the performance evaluation and improvement for practical Otto engines.

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Żmudka, Zbigniew, Stefan Postrzednik, and Grzegorz Przybyła. "Inverse Problem of Selection of the Theoretical Cycle for the Real Cycle of Internal Combustion Engine." Journal of KONES 26, no. 2 (June 1, 2019): 197–204. http://dx.doi.org/10.2478/kones-2019-0050.

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Abstract The effectiveness of work of an internal combustion engine can be assessed by means of the energy efficiency: theoretical, internal and effective... In the problem regarding the efficiency of obtaining a work from the tested SI engine, the theoretical Seiliger-Sabathe cycle was adopted as a reference model for the real engine cycle. For comparison, the OTTO cycle was also analysed. The engine indicating allows direct determination only of internal work. However, determining the work of the theoretical cycle first requires solving the problem of selecting the parameters of the theoretical cycle, according to the real cycle of the engine (inverse problem). In order uniquely to determine the course of the theoretical Seiliger-Sabathe cycle, it is necessary to determine the parameters of the starting point and the heat distribution number. The selection of the theoretical cycle for the real cycle, within the scope of determining the number of heat distribution, is to some extent of a contractual nature. Therefore, the problem of determining the number of heat distribution was solved by two own original methods. A comparison of the real cycle with the theoretical cycle determined for it is presented.

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Cakir, Mehmet. "The numerical thermodynamic analysis of Otto-Miller Cycle (OMC)." Thermal Science 20, no. 1 (2016): 363–69. http://dx.doi.org/10.2298/tsci150623131c.

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This paper presents a thermodynamic analysis for an irreversible Otto-Miller Cycle (OMC) by taking into consideration heat transfer effects and internal irreversibilities resulting from compression and expansion processes. In the analyses, the influences of the miller cycle ratio, combustion and heat loss constants and inlet temperature have been investigated relations with efficiency in dimensionless form. The dimensionless power output and power density and thermal efficiency relations have been computationally obtained versus the engine design parameters with respect to combustion and heat transfer constants. The results demonstrate that the heat transfer and combustion constants have considerable effects on the cycle thermodynamic performance. This situation theoretically verified for OMC.

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Hwang, Soon-kyu, and Byung-gun Jung. "Methane Number Control of Fuel Gas Supply System Using Combined Cascade/Feed-Forward Control." Journal of Marine Science and Engineering 8, no. 5 (April 28, 2020): 307. http://dx.doi.org/10.3390/jmse8050307.

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Liquefied natural gas began to attract attention as a ship fuel to reduce environmental pollution and increase energy efficiency. During this period, highly efficient internal combustion engines emerged as the new propulsion system instead of steam turbines. However, Otto-cycle engines must use fuel that meets the methane number that was given by the engine makers. The purpose of this study was to develop a system configuration and a control method of methane number adjustment using combined cascade/feed-forward controllers for marine Otto-cycle engines to improve reference tracking and the disturbance rejection. The main principle involves controlling the downstream gas temperature of the fuel gas supply system to meet the required methane number. Three controllers are used in the combined cascade/feed-forward control for adjusting the downstream of the gas temperature: the cascade loop has two controllers and the feed-forward has one controller. The two controllers in the cascade loop are designed with proportional–integral (PI) controllers. The remaining controller is based on feed-forward control theory. A simulation was conducted to verify the efficacy of the proposed method, focusing on the disturbance rejection and set-point tracking, in comparison with a single PI controller, a single PI controller with feed-forward, and cascade control.

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Clucas, D. M., and J. K. Raine. "A New Wobble Drive with Particular Application in a Stirling Engine." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 208, no. 5 (September 1994): 337–46. http://dx.doi.org/10.1243/pime_proc_1994_208_136_02.

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Swash plate or wobble mechanisms used in engine drives commonly require gearing, slides and/or spherical bearings to connect the piston rods to the transfer mechanism and react to the torque produced. This paper briefly reviews the literature on this class of engine mechanism and presents the theory and form design of a new wobble yoke mechanism which achieves single degree of freedom rotational motion for all bearings, enabling the use of sealed rolling element bearings and eliminating the need for sliding surfaces or gears. The mechanism has been first applied in a liquefied petroleum gas-fuelled integrated Stirling engine electric generator system for battery charging. The hermetically sealed system gives 200 watt d.c. electrical output and is configured for charging 12 volt batteries. A square four-cylinder double-acting configuration is used, with pistons equispaced and parallel to the output shaft. The mechanism is easily parametrically scaled to different engine sizes. It also has potential application in compressors, pumps, other Stirling cycle machines or Otto cycle engines. Development of mechanical design features and thermodynamic and electrical development of the Stirling engine generator are to be described in a subsequent paper, to be published in the next Part C issue.

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Dobrucali, Erinc. "The effects of the engine design and running parameters on the performance of a Otto–Miller Cycle engine." Energy 103 (May 2016): 119–26. http://dx.doi.org/10.1016/j.energy.2016.02.160.

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Peña, Francisco J., Oscar Negrete, Gabriel Alvarado Barrios, David Zambrano, Alejandro González, Alvaro S. Nunez, Pedro A. Orellana, and Patricio Vargas. "Magnetic Otto Engine for an Electron in a Quantum Dot: Classical and Quantum Approach." Entropy 21, no. 5 (May 20, 2019): 512. http://dx.doi.org/10.3390/e21050512.

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We studied the performance of classical and quantum magnetic Otto cycle with a working substance composed of a single quantum dot using the Fock–Darwin model with the inclusion of the Zeeman interaction. Modulating an external/perpendicular magnetic field, in the classical approach, we found an oscillating behavior in the total work extracted that was not present in the quantum formulation.We found that, in the classical approach, the engine yielded a greater performance in terms of total work extracted and efficiency than when compared with the quantum approach. This is because, in the classical case, the working substance can be in thermal equilibrium at each point of the cycle, which maximizes the energy extracted in the adiabatic strokes.

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Wang, Hao, Guo Xing Wu, and Ji Kang Zhong. "Performance Analysis and Parametric Optimum Criteria of a Micro Nano Scaled Otto Engine Cycle." Advanced Materials Research 308-310 (August 2011): 752–61. http://dx.doi.org/10.4028/www.scientific.net/amr.308-310.752.

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The wave character of atoms can produce Casimir-like size effects in gases confined in a narrow box. A general micro/nano scaled model of the Otto engine cycle working with an ideal gas is used to discuss the Casimir-like size effects. Based on the model, expressions of the work output and efficiency are derived analytically. By means of numerical calculation and illustration, the influence of the surface areaon the performance of the cycle are discussed and evaluated in detail. Furthermore, some optimal operating regions including those for the work output, efficiency and the optimal region of the volume ratio and the surface area ratio are determined and evaluated. The results attained here are useful for designing of a micro/nano scaled heat exchange device.

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Hutchinson, Harry. "Heavy-duty LNG." Mechanical Engineering 124, no. 05 (May 1, 2002): 59. http://dx.doi.org/10.1115/1.2002-may-5.

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This article focuses on the natural gas advocates who have set their sights on the diesel engine, and some of their new ideas are getting a workout in California. Otto-cycle engines fueled by natural gas are common in cities as the operators of buses and other vehicle fleets try to keep emissions in check. Natural gas mixes with air before it enters the cylinder. An electronically controlled injector introduces a small amount of diesel fuel at the end of the compression stroke to begin ignition. According to Caterpillar, more than 85 percent of the fuel consumed can be natural gas in some applications. Cummins Westport Inc., Vancouver, BC, is testing a 400-hp diesel engine that burns natural gas. The system injects diesel as a pilot and then follows it with natural gas. Electronic controls determine the timing and quantity of natural gas.

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Mello, Pedro, Fabiano Wildner, Giovanni Souza de Andrade, Renato Cataluña, and Rosângela da Silva. "Combustion time of the oxygenated and non-oxygenated fuels in an Otto cycle engine." Journal of the Brazilian Society of Mechanical Sciences and Engineering 36, no. 2 (October 27, 2013): 403–10. http://dx.doi.org/10.1007/s40430-013-0094-y.

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38

Siahaan, Herbert Hasudungan, Armansyah H Tambunan, Desrial, and Soni Solistia Wirawan. "Rancang Bangun dan Pengujian Penghalang Heliks sebagai Pencampur Udara-Biogas pada Motor Otto." Jurnal Keteknikan Pertanian 8, no. 3 (March 5, 2021): 89–96. http://dx.doi.org/10.19028/jtep.08.3.89-96.

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A helical barrier as air-biogas mixing device was designed and tested for direct use of biogas from digester in otto cycle generator set. Homogeneity of the air-fuel mixture can give better combustion reaction and increase engine power. The design was based on simulation, which shows that a 0.039 m length of helical barrier gave a 5% increase in power compared to non-helical barrier. Likewise, the simulations also showed that the helical barrier reduced specific fuel consumption (SFC) by 8%. Accordingly, the mixer with helical barrier was designed, and fabricated. Its performance test confirms the improvement resulted by using helical barriers as air-biogas mixer in the engine. The experiment showed that the power increased by 5% when using helical barrier, while SFC decreased by 4.5%. It is concluded that the helical barrier can increase the homogeneity of the mixture resulting in better engine performance. Besides, emissions produced from the engine using a helical barrier also decreased.

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Oliveira, B. L. N., E. F. Jaguaribe, A. F. Bezerra, A. S. Rumão, and B. L. C. Queiroga. "A DIESEL ENGINE CONVERTED INTO OTTO CYCLE ENGINE: THE INFLUENCE OF THE SPARK ADVANCE ON ITS PERFORMANCE AND ON NOx EMISSIONS." Revista de Engenharia Térmica 12, no. 1 (June 30, 2013): 37. http://dx.doi.org/10.5380/reterm.v12i1.62027.

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This paper analyzes the performance of a diesel engine converted into an Otto cycle engine and its Nitrogen dioxide emissions in terms of the spark advance variation. The tests were conducted on a Perkins diesel engine 1104C - 44TAG turbocharged, whose compression ratio was reduced to 9.33:1. After conversion the engine started operating with liquefied petroleum gas (LPG) and running just with stoichiometric mixtures. The tests have been limited to 10 to 40 kW, always at 1800 rpm. During the experiments the ignition advance angle ranged from 5º up to 27º (BTDC), using the increment of 5°, whenever possible. Particularly at 40 kW, the range of the ignition advance was 15º to 20º. The results showed a significant influence of the spark advance angle on the fuel consumption, on the temperature and on the NOx emissions, as well as on the magnitude of the generated power.

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Huleihil, Mahmoud. "Effects of Pressure Drops on the Performance Characteristics of Air Standard Otto Cycle." Physics Research International 2011 (July 27, 2011): 1–7. http://dx.doi.org/10.1155/2011/496057.

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The effects of pressure drops on the performance characteristics of the air standard Otto cycle are reported. The pressure drops are assumed as constant values independent of the engine size. It has been shown that the pressure drops to about 60% of the maximum pressure in the ideal cycle (Curto-Risso et al., 2008). Three different models are studied: constant pressure model, reversible adiabatic expansion model and polytropic expansion model. The findings of this study show that, at this level of pressure drop, the maximum efficiency of the Otto cycle is reduced by 15% approximately based on the constant pressure model. The combined effect of pressure drop with other modes of irreversibility, for example, internal irreversibility and heat leaks, could reduce the maximum efficiency into very low values (approximately 30%). The reversible adiabatic model predicts reduction of 13% in efficiency at 40% pressure drop levels but at the price of zero power production. On the other hand, the polytropic expansion model predicts 40% reduction in efficiency for the same level of pressure drop (40%). All three models show that the power output is very sensitive to pressure drop.

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Insinga, Andrea R. "The Quantum Friction and Optimal Finite-Time Performance of the Quantum Otto Cycle." Entropy 22, no. 9 (September 22, 2020): 1060. http://dx.doi.org/10.3390/e22091060.

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In this work we considered the quantum Otto cycle within an optimization framework. The goal was maximizing the power for a heat engine or maximizing the cooling power for a refrigerator. In the field of finite-time quantum thermodynamics it is common to consider frictionless trajectories since these have been shown to maximize the work extraction during the adiabatic processes. Furthermore, for frictionless cycles, the energy of the system decouples from the other degrees of freedom, thereby simplifying the mathematical treatment. Instead, we considered general limit cycles and we used analytical techniques to compute the derivative of the work production over the whole cycle with respect to the time allocated for each of the adiabatic processes. By doing so, we were able to directly show that the frictionless cycle maximizes the work production, implying that the optimal power production must necessarily allow for some friction generation so that the duration of the cycle is reduced.

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Nunes, M. A. A., R. C. Silva, A. B. S. Oliveira, and G. C. Peron. "DYNAMICAL SIMULATION OF A VALVETRAIN MECHANISM: AN ENGINEERING EDUCATION APPROACH." Revista de Engenharia Térmica 12, no. 1 (June 30, 2013): 17. http://dx.doi.org/10.5380/reterm.v12i1.62013.

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The present work aims to present a valvetrain model considering the dynamics functioning aspects of an Otto’s engine. The model will be constructed using Adams/View® software, which is a powerful modeling and simulating environment of dynamic systems. It allows building, simulating, refining and optimizing any mechanical system. In fact, the model will help engineering students to understand how the mechanism works, in terms of displacement, velocity and acceleration of the valve as a function of the time. It is also possible to know the behavior of the force in the spring as a function of the time and, finally, the torque applied in the cam due to a angular velocity input. Relative to spring force, during the Otto engine cycle, the cam lobe must be able to open and close the valve as fast and as smoothly as possible. The force responsible to close the valve is applied by the valve spring, which is also responsible for keeping contact between the cam lobe and the valve. Dynamic forces impose limits on cam and valve lift. Thus, the simulation model allows determining these forces and displacements through the cam rotation. As main objectives the authors wish to make available a model which is capable to show in 3D the animation of a valvetrain mechanism of an Otto engine, obtaining the main curves for analysis and evaluation of this mechanism performance.

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Nie, Wenjie, Qinghong Liao, ChunQiang Zhang, and Jizhou He. "Micro-/nanoscaled irreversible Otto engine cycle with friction loss and boundary effects and its performance characteristics." Energy 35, no. 12 (December 2010): 4658–62. http://dx.doi.org/10.1016/j.energy.2010.09.039.

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Queiroga, B. L. C., E. F. Jaguaribe, M. S. J. Gonçalves, B. L. N. Oliveira, and A. S. Rumão. "CONVERSION OF TURBOCHARGED DIESEL ENGINE TO OPERATE SOLELY WITH HYDROUS ETHANOL." Revista de Engenharia Térmica 12, no. 1 (June 30, 2013): 41. http://dx.doi.org/10.5380/reterm.v12i1.62028.

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This paper discusses the conversion of a turbocharged diesel engine to operate with hydrous ethanol, using procedures developed in Innovation Lab of UFPB, IL. An diesel engine, brand Perkins, model 1104C-44TAG2, was converted to operate with hydrous ethanol at the time that it amended its compression ratio of 18:1 to 9.3:1, suitable for an Otto Cycle engine to non-occurrence of detonation fuel. Comparing experimental data generated for the converted engine tests (which ranged the ignition advance, stoichiometric air/fuel ratio and rotation at 1800 rpm) with those obtained in tests with the original engine, and converted, 45 kWe, a cost reduction of 34% with Ignition Advance of 20°. It was taken into account in this analysis, and data on fuel consumption, the cost of diesel, R$ 1.90/liter, and hydrous ethanol, R$ 0.70/liter. Regarding the gaseous emissions, depending on the load, it was found that the NOX ranged from 50 to 1050 ppm, CO, 1 to 3%, CO2, 12 to 15% and HC 150 to 450 ppm.

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Chen, Lingen, Yanlin Ge, Chang Liu, Huijun Feng, and Giulio Lorenzini. "Performance of Universal Reciprocating Heat-Engine Cycle with Variable Specific Heats Ratio of Working Fluid." Entropy 22, no. 4 (March 31, 2020): 397. http://dx.doi.org/10.3390/e22040397.

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Considering the finite time characteristic, heat transfer loss, friction loss and internal irreversibility loss, an air standard reciprocating heat-engine cycle model is founded by using finite time thermodynamics. The cycle model, which consists of two endothermic processes, two exothermic processes and two adiabatic processes, is well generalized. The performance parameters, including the power output and efficiency (PAE), are obtained. The PAE versus compression ratio relations are obtained by numerical computation. The impacts of variable specific heats ratio (SHR) of working fluid (WF) on universal cycle performances are analyzed and various special cycles are also discussed. The results include the PAE performance characteristics of various special cycles (including Miller, Dual, Atkinson, Brayton, Diesel and Otto cycles) when the SHR of WF is constant and variable (including the SHR varied with linear function (LF) and nonlinear function (NLF) of WF temperature). The maximum power outputs and the corresponding optimal compression ratios, as well as the maximum efficiencies and the corresponding optimal compression ratios for various special cycles with three SHR models are compared.

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Kovalov, Serhii. "DEVELOPMENT OF THE COMBUSTION CHAMBER OF GAS ENGINE, CONVERTED ON THE BASIS OF DIESELS D-120 OR D-144 ENGINES TO WORK FOR ON LIQUEFIED PETROLEUM GAS." Avtoshliakhovyk Ukrayiny, no. 3 (259) ’ 2019 (October 17, 2019): 2–8. http://dx.doi.org/10.33868/0365-8392-2019-3-259-2-8.

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The expediency of using vehicles of liquefied petroleum gas as a motor fuel, as com-pared with traditional liquid motor fuels, in particular with diesel fuel, is shown. The advantages of converting diesel engines into gas ICEs with forced ignition with respect to conversion into gas diesel engines are substantiated. The analysis of methods for reducing the compression ratio in diesel engines when converting them into gas ICEs with forced ignition has been carried out. It is shown that for converting diesel engines into gas ICEs with forced ignition, it is advisable to use the Otto thermo-dynamic cycle with a decrease in the geometric degree of compression. The choice is grounded and an open combustion chamber in the form of an inverted axisymmetric “truncated cone” is developed. The proposed shape of the combustion chamber of a gas internal combustion engine for operation in the LPG reduces the geometric compression ratio of D-120 and D-144 diesel engines with an unseparated spherical combustion chamber, which reduces the geometric compression ratio from ε = 16,5 to ε = 9,4. The developed form of the combustion chamber allows the new diesel pistons or diesel pistons which are in operation to be in operation to be refined, instead of making special new gas pistons and to reduce the geometric compression ratio of diesel engines only by increasing the combustion chamber volume in the piston. This method of reducing the geometric degree of compression using conventional lathes is the most technologically advanced and cheap, as well as the least time consuming. Keywords: self-propelled chassis SSh-2540, wheeled tractors, diesel engines D-120 and D-144, gas engine with forced ignition, liquefied petroleum gas (LPG), compression ratio of the internal com-bustion engine, vehicles operating in the LPG.

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Rumão, A. S., E. F. Jaguaribe, A. F. Bezerra, B. L. N. Oliveira, and B. L. C. Queiroga. "ELECTRICITY GENERATION FROM BIOMASS GASIFICATION." Revista de Engenharia Térmica 13, no. 1 (June 30, 2014): 28. http://dx.doi.org/10.5380/reterm.v13i1.62065.

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Brazil is among the ten largest consumers of electricity in the world, and in the last decades its demand for electricity has been continuously increasing. As a consequence it has not been capable to ensure enough expansion of its electric power network, mostly affecting isolated communities. The present study discusses the use of a system formed by an Indian residue biomass gasifier and a 36 kVA engine-generator, which should generate 20 kWe, using gas-alone mode engine. The engine was, originally, a MWM D229-4 diesel engine, which was converted into an Otto cycle to run only with producer gas. The system performance was evaluated for different engine’s advance ignition angles, and two types of biomass. As the Indian gasifier was designed to operate just with dual-fuel mode to feed a gas-alone engine, some changes in the gasifier's water cleaning system were required. The modifications enabled the system to improve the power generation which overcame the 20 kWe reaching 26 kWe. Technical and economic considerations showed that the bioelectricity based on bio-residual gasifier may be a viable and ecological option for regions having enough biomass residue and not served by the system network.

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Shao, Yude, Sangdeuk Yoon, and Hokeun Kang. "Dynamic simulation of fuel tank aging for LNG‐fueled ship apparatus in an X‐DF Otto cycle engine." Energy Science & Engineering 7, no. 6 (September 26, 2019): 3005–19. http://dx.doi.org/10.1002/ese3.475.

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Plohberger, D. C., T. Fessl, F. Gruber, and G. R. Herdin. "Advanced Gas Engine Cogeneration Technology for Special Applications." Journal of Engineering for Gas Turbines and Power 117, no. 4 (October 1, 1995): 826–31. http://dx.doi.org/10.1115/1.2815471.

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In recent years gas Otto-cycle engines have become common for various applications in the field of power and heat generation. Gas engines in gen-sets and cogeneration plants can be found in industrial sites, oil and gas field application, hospitals, public communities, etc., mainly in the U.S., Japan, and Europe, and with an increasing potential in the upcoming areas in the far east. Gas engines are chosen sometimes even to replace diesel engines, because of their clean exhaust emission characteristics and the ample availability of natural gas in the world. The Austrian Jenbacher Energie Systeme AG has been producing gas engines in the range of 300 to 1600 kW since 1960. The product program covers state-of-the-art natural gas engines as well as advanced applications for a wide range of alternative gas fuels with emission levels comparable to Low Emission (LEV) and Ultra Low Emission Vehicle (ULEV) standards. In recent times the demand for special cogeneration applications is rising. For example, a turnkey cogeneration power plant for a total 14.4 MW electric power and heat output consisting of four JMS616-GSNLC/B spark-fired gas engines specially tuned for high altitude operation has been delivered to the well-known European ski resort of Sestriere. Sestriere is situated in the Italian Alps at an altitude of more than 2000 m (approx. 6700 ft) above sea level. The engines feature a turbocharging system tuned to an ambient air pressure of only 80 kPa to provide an output and efficiency of each 1.6 MW and up to 40 percent @ 1500 rpm, respectively. The ever-increasing demand for lower pollutant emissions in the U.S. and some European countries initiates developments in new exhaust aftertreatment technologies. Thermal reactor and Selective Catalytic Reduction (SCR) systems are used to reduce tailpipe CO and NOx emissions of engines. Both SCR and thermal reactor technology will shift the engine tuning to achieve maximum efficiency and power output. Development results are presented, featuring the ultra low emission potential of biogas and natural gas engines with exhaust aftertreatment.

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Marques, Adriano da S., Monica Carvalho, Álvaro A. V. Ochoa, Ronelly J. Souza, and Carlos A. C. dos Santos. "Exergoeconomic Assessment of a Compact Electricity-Cooling Cogeneration Unit." Energies 13, no. 20 (October 16, 2020): 5417. http://dx.doi.org/10.3390/en13205417.

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This study applies the SPecific Exergy COsting (SPECO) methodology for the exergoeconomic assessment of a compact electricity-cooling cogeneration system. The system utilizes the exhaust gases from a 126 hp Otto-cycle internal combustion engine (ICE) to drive a 5 RT ammonia–water absorption refrigeration unit. Exergy destruction is higher in the ICE (67.88%), followed by the steam generator (14.46%). Considering the cost of destroyed exergy plus total cost rate of equipment, the highest values are found in the ICE, followed by the steam generator. Analysis of relative cost differences and exergoeconomic factors indicate that improvements should focus on the steam generator, evaporator, and absorber. The cost rate of the fuel consumed by the combustion engine is 12.84 USD/h, at a specific exergy cost of 25.76 USD/GJ. The engine produces power at a cost rate of 10.52 USD/h and specific exergy cost of 64.14 USD/GJ. Cooling refers to the chilled water from the evaporator at a cost rate of 0.85 USD/h and specific exergy cost of 84.74 USD/GJ. This study expands the knowledge base regarding the exergoeconomic assessment of compact combined cooling and power systems.

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Journal articles on the topic 'Otto-cycle engine'

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