PDF superior Effect of using hydrogen in the power and performance of an internal combustion engine

Effect of using hydrogen in the power and performance of an internal combustion engine

Effect of using hydrogen in the power and performance of an internal combustion engine

Con la intención de aportar con un estudio y alternativa tecnológica eficiente para disminuir las emisiones contaminantes y obtener un mejor rendimiento en la pot[r]

12 Lee mas

Characterization of the combustion process and cycle to cycle variations in a spark ignition engine fuelled with natural gas/hydrogen mixtures

Characterization of the combustion process and cycle to cycle variations in a spark ignition engine fuelled with natural gas/hydrogen mixtures

A study is presented of the influence of using mixtures of natural gas and hydrogen in different fractions (0, 25, 50, 75, 100%) on the combustion velocity and cycle-to-cycle var- iations in a spark ignition engine. The experimental facility consists of a single-cylinder spark ignition engine. The engine rotational speeds are 1000, 1750 and 2500 rpm. Fuel/air equivalence ratio was kept constant equal to 0.7 during the experiments. A two-zone thermodynamic combustion diagnosis model, based on solving the mass and energy conservation equations, is used to analyze the experimentally obtained pressure com- bustion chamber in the engine. The two-zone model considers a spherical flame front centred at the spark plug, and solves the intersection of the flame front with the piston, cylinder head and cylinder wall, in order to provide the values of the flame radius corre- sponding to the burned mass volume and the surfaces for heat to the piston and walls. An automatic procedure based on genetic algorithms is used to determine the optimum pa- rameters needed for combustion diagnosis: Angular positioning and pressure offset of the pressure register, dynamic compression ratio, and heat transfer coefficients. The paper focuses on using the values of the burning velocity computed from the pressure register and especially on the analysis of the cycle to cycle variation in the natural gas/hydrogen fuelled engine, quantified through the standard deviation and the coefficient of variation of the burning speed. Increasing the hydrogen content in the mixture with natural gas in- creases its burning velocity. This effect is linear with hydrogen fraction, except for very high values of the fraction, when the effect of hydrogen dominates combustion. Addi- tionally, and of practical importance, increasing the hydrogen fraction reduces the relative dispersion of combustion. This effect of hydrogen addition on reducing combustion vari- ability is evident from 25% hydrogen content.
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11 Lee mas

The adaptation of sustainable biojet fuels and its effect on aircraft engine maintenance

The adaptation of sustainable biojet fuels and its effect on aircraft engine maintenance

million tons for optimistic scenarios in the year 2030 [4]. The reduction of emissions is considered to be more a matter of engine design than fuel technology. The adverse effects of the general degradation of combustion performance in kerosene for over 25 years cause emissions and engine life span to be in need of consideration, and this has led to a rapid demand for new and alternative fuel [5]. These rapid changes bring a serious effect in creating global carbon neutrality, where in this case, improvements in carbon engine outputs alone will not work. Adaptation and current work with new ‘alternative energy’ with zero carbon distributions will help to reduce air pollution that directly impacts the atmosphere [6]. Alternative energy in commercial aviation can be defined as using biojet fuel, gas to liquid, and hydrogen cells. The use of battery and hydrogen cells addresses some issues such as weight limitation, and thus it will not be discussed in this paper. Similarly, GTL or gas to liquid will not be considered in this article as it has an adverse feedback on the environment [7].
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11 Lee mas

Performance and emissions of an agricultural diesel engine fuelled with different diesel and methyl ester blends

Performance and emissions of an agricultural diesel engine fuelled with different diesel and methyl ester blends

This paper shows the results of an investigation carried out to assess the application of different fuels produced by blending diesel fuel with methyl ester obtained from mixture of 75% (v/v) sunflower oil and 25% (v/v) used cooking oil on a Kubota agricultural indirect injection diesel engine, natural aspirated, and with a rated horsepower of 19.7 kW. Seven fuels, namely diesel fuel; 90:10, 80:20, 70:30, 50:50, 25:75 and 0:100 (%v/v) blends were prepared and tested for the performance of the diesel engine in accordance with the standardised OECD test code 2. The test results showed that the performance of the engine was satisfactory without a significant reduction in power output and torque with blends smaller than 50%. Fuel consumptions with biodiesel were higher than that when fuelled with diesel but differences were not very marked up to 30% blends. As the reduction of the engine thermal efficiency was less than the corresponding reduction in heating value of the different biodiesel blends, the latter resulted in a more complete combustion in comparison with diesel fuel. The oxides of nitrogen (NO x ) emissions were found to be reduced as the biodiesel concentration increase,
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9 Lee mas

Feasibility study of hydrogen fueled internal combustion hybrid bus operating under real traffic urban conditions in Buenos Aires, Argentina

Feasibility study of hydrogen fueled internal combustion hybrid bus operating under real traffic urban conditions in Buenos Aires, Argentina

The results also show the high potential of hydrogen fueled buses to reduce GHG emis- sions. However, if electrolysis with the average carbon foot print of the today’s Argentine grid is used, the hydrogen fueled bus platforms have no greenhouse gas emission edge over CB. But assuming 2025’s composition of power generation sources, the GHG emission reduc- tion using electrolysis is higher than using a SMR. Scenario four has shown the potential of hydrogen fueled buses using renewable energy source in the production of electricity. Further- more, scenario four has shown, looking at GHG emissions, that the efficiency becomes less important when the amount of renewable energy sources in the power generation production increase. Using 100% renewable energy sources, the efficiency benefit do not lead to benefits in the avoidance of GHG emissions.
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77 Lee mas

Study of the cycle-to-cycle variations of an internal combustion engine fuelled with natural gas/hydrogen blends from the diagnosis of combustion pressure

Study of the cycle-to-cycle variations of an internal combustion engine fuelled with natural gas/hydrogen blends from the diagnosis of combustion pressure

A methodology is presented for studying the influence of using alternative fuels on the cycle-to-cycle variations of a spark ignition engine which has been fuelled with mixtures of natural gas and hydrogen in different proportions (0e100%). The experimental facility consists of a single-cylindrical spark ignition engine coupled to an asynchronous machine with a constant engine rotation speed of 1500 rpm. A thermodynamic combustion diag- nostic model based on genetic algorithms is used to evaluate the combustion chamber pressure data experimentally obtained in the mentioned engine. The model is used to make the pressure diagnosis of series of 830 consecutive engine cycles automatically, with a high grade of objectivity of the combustion analysis, since the relevant adjustment pa- rameters (i.e. pressure offset, effective compression ratio, top dead center angular position, heat transfer coefficients) are calculated by the genetic algorithm. Results indicate that the combustion process is dominated by the turbulence inside the combustion chamber (generated during intake and compression), showing little dependency of combustion variation on the mixture composition. This becomes more evident when relevant com- bustion variables are plotted versus the Mass Fraction Burned of each mixture. The only exception is the case of 100% hydrogen, due to the inherent higher laminar speed of hydrogen that causes combustion acceleration and thus turbulence generation.
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11 Lee mas

The effect of heat transfer laws and thermal conductances on the local stability of an endoreversible heat engine

The effect of heat transfer laws and thermal conductances on the local stability of an endoreversible heat engine

the power and efficiency decrease in both cases (k = 1 and k = − 1). It is interesting that the minimum value for the relaxation time at √ τ = α/β is observed for the case k = 1. On the other hand, the efficiency is constant (case k = 1), and is a decreasing function (case k = −1) of the ratio β/α, whereas the stability, in both cases, declines as α/β → 0 or β/α → 0. Physically, the limits β/α → 0 and α/β → 0 correspond to reversible absorption of heat and reversible release of heat, respectively. Our local analysis reveals that in these limits, for the cases k = 1 and k = −1, any small perturbation in the internal temperature (y in the case of absorption and x in the case of release) decays very slowly—in fact, the time to return to the steady-state temperature is infinity. For this reason the system loses its stability. At the same time, the temperature (x in the case of absorption and y in the case of release) decays almost instantaneously.
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10 Lee mas

Power increasing measurement and analysis based on modified mechanical systems added to a turbocharged internal combustion engine

Power increasing measurement and analysis based on modified mechanical systems added to a turbocharged internal combustion engine

In this project would be explained the principal modifications to an internal combustion engine with a turbocharged, taking into account the way a four-stroke engine works as shown on the Figure 1. Four-Stroke Engine Cycle. It all stars at the admission of the air to the cylinders, this step is called “Intake” in which air comes in and the fuel is injected, in this step there are different aspects to be modified, you can increase the amount of air that enter in to the chamber, you can also increment the amount of fuel that enter in to the chamber or you can decrease the temperature of the air coming in, to have air with a higher density.
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52 Lee mas

Comparative theoretical study of thermodynamics characteristics of performance of a combustion engine operating with gasoline and with natural gas

Comparative theoretical study of thermodynamics characteristics of performance of a combustion engine operating with gasoline and with natural gas

In this article a comparative study of some performance characteristics and parameters of an internal combustion engine operating with gasoline and with natural gas is presented. The software of calculation of chemical equilibrium Stanjan ® , for the determination of the composition of combustion products and the calculation of the flame temperatures, is implemented. For the calculation of other performance parameters, like the indicated mean effective pressure, the simulation of a motor is carried out by means of software Engine Simulation Program ® . The analysis and interpretation of the results are established and conclusions in relation to the advantages and disadvantages of the conversion of a gasoline motor to natural gas, are planted from the thermodynamic perspective.
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6 Lee mas

The effect of morality intensity and internal control regarding the accounting fraud tendency

The effect of morality intensity and internal control regarding the accounting fraud tendency

The government’s internal control system consists of five elements, namely : control environment (a condition in government agencies to build awareness of all the personnel of the importance of controlling an organization in carrying out activities under his responsibility thus increasing the effectiveness of internal controls through enforcement of integrity and ethical values, commitment to competence, leadership conducive, the establishment of an organizational structure that fits the needs, delegation of authority and appropriateresponsibility, and developing and implementing sound policies on human resource development), Risk assessment (assessment of possible situations that threaten the achievement of the goals and objectives of government agencies whose activities include the identification, analysis, and manage the risks that are relevant to the process or organizational activities), Control activities (control activities are necessary action to address the risk and the implementation and execution of policies and procedures to ensure that the risk prevention has been effectively implemented), Information and communication (Information is data that has been processed to be used for decision making in the context of implementation of tasks and functions of government agencies, while communication is the process of delivering a message or information using a particular symbol or emblem either directly or indirectly to obtain feedback), and Monitoring (process of assessing the performance quality of internal control systems and processes that provide confidence that the findings of audits and other evaluations soon followed.)
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8 Lee mas

Energy and exergy evaluation in a 1.6L Otto cycle internal combustion engine

Energy and exergy evaluation in a 1.6L Otto cycle internal combustion engine

This paper aimed to evaluate the behavior of an Otto Cycle internal combustion of a 1.6 L engine measuring its performance by the energy and exergy balance. The energy calculation was developed in a previously set route at a constant speed of 50 km/h and 90 km/h. It was determined, that the analysis of the energy and exergy balance contributes to recognize the performance of an internal combustion after the experimentation based on observation, measurement, methods of induction, deduction and synthesis. Also, it was resolved that the engine has an average energy efficiency of 27.57 % for a speed of 50 km/h, while the total exergy flow of the system is 22 %. Therefore, there is no significant difference with the efficiency results at 90 km/h.
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12 Lee mas

Performance and efficiency in Colombia's power utilities: an assessment of the 1994 reform

Performance and efficiency in Colombia's power utilities: an assessment of the 1994 reform

The basic intuition that one must recall in the measurement of a plant productive efficiency from DEA estimation is the following: consider a set of plants that use different combinations of inputs to produce one unit of a homogeneous output (electricity fits concept). If every plant is producing efficiently, all are in best practice isoquant. In the case that one plant is demanding more inputs in order to produce one unit of output, we are able to say that the plant is inefficient to the best practice isoquant. Data Envelope Analysis (DEA) allows us to calculate a measure of plant technical efficiency. In particular, DEA uses a sequence of linear programs to construct a transformation frontier to compute efficiency measures relative to this reference technology. Inefficiency is measured as the ratio of the radial distance from the origin to the combination of input usage in an input space and the radial distance from the origin to the frontier, which is a isoquant made up of the input combinations of the remaining group of firms which are considered efficient (i.e. pair wise input - one output in an Cartesian plane). This ratio will take a value between zero and one. If a plant has an efficiency score of 1, one says that is technically efficient. If the score is less than 1 then the plant is inefficient. For instance if plant B has a score 0.8 and plant A has a score of 1, then plant B is 20% inefficient relative to the production frontier. That is if plant B uses its inputs as plant A, then she would increase its output in 20%. The above measurement is called as non-parametric input-oriented efficiency scores. 13
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31 Lee mas

The Effect of Horizontal Mergers on Efficiency and Market Power: An Application to the Argentine Hamburger Market

The Effect of Horizontal Mergers on Efficiency and Market Power: An Application to the Argentine Hamburger Market

The analysis performed in the previous sections suggests that the effect of the BRF/MRP merger was in general favorable to the Argentine hamburger consumers, since it induced a price decrease and a quantity increase (especially for the brands manufactured by BRF). This result, however, is not due to a reduction in the degree of unilateral market power that the merging company had in the Argentine hamburger market. Quite the contrary, that degree of market power seemed to have increased due to the merger. Nevertheless, the BRF/MRP transaction seems to have induced an important cost reduction that was partially passed through consumers, probably influenced by the fact that other hamburger producers (e.g., Swift, Paladini, etc.) may have increased their productive efficiency levels as well.
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14 Lee mas

Collaborative and individual strategic planning effect on performance of an oral task

Collaborative and individual strategic planning effect on performance of an oral task

This article reports the initial findings of an MA in Applied Linguistics on the effect collaborative and individual strategic planning have on performance of an oral task by young learners of English as an L2 in Brazil. Strategic planning (Ellis, 2003, 2005) is an important concept within the task-based approach (TBA), as this condition may trigger metacognitive processes.Yet, only a few studies have had young learners of English as participants in strategic planning research. The participants, teenage learners,enrolled in the second year of a public high school in Florianópolis (Brazil), performed two monological oral tasks under two different planning conditions: (a) collaborative, and (b) individual. The oral messages sent using WhatsApp were analysed in terms of accuracy, fluency and outcome (pragmatic). In addition, the participants filled in post-task questionnaires after the performance of each task, aiming at unveiling their perception on the conditions and tasks. In this paper, data from the pilot study as well as some preliminary results were analysed. In spite of the absence of statistically significant results for accuracy and fluency, results indicated a trend supporting the collaborative work condition. While, the qualitative data showed strong support for the collaborative planning condition. These initial findings, in general, support the use of L2 oral tasks involving strategic planning in the public school context.
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14 Lee mas

The role of separation of scales in the description of spray combustion

The role of separation of scales in the description of spray combustion

evolution equations along the trajectories (14)- (16) are expressed for each droplet class with use made of the Eulerian differential operator d/dt — d()/dt + v'j • VQ. This continuum formu- lation is often simpler than formulations involving tracking of individual droplets and greatly facili- tates analyses of laminar sprays. However, the continuum description of the liquid phase is known to be inadequate for addressing inertial sprays with multiple crossings of droplet trajecto- ries, as occurs, for example, in turbulent flows or in the presence of recirculating flow regions when the particle size is not small enough. Although for some laminar flow configurations, such as those considered in Sections 6 and 7, introduction of specific modifications to the formulation renders the Eulerian description valid, methods based on Lagrangian descriptions of the liquid phase are in general needed in the presence of droplet cross- ings. A promising alternative approach for tack- ling the crossing of droplet trajectories in inertial sprays, based on field formulations of the liquid phase, employs quadrature methods of moments to solve the kinetic spray equation [45]. Despite the significant progress made recently in the devel- opment of these formulations [46,47], more work remains to be done to warrant full applicability to spray-combustion problems [48].
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29 Lee mas

Patterns and determinants of immigrants’ internal mobility : an analysis of the foreign born in the Chilean social support registry

Patterns and determinants of immigrants’ internal mobility : an analysis of the foreign born in the Chilean social support registry

Daniel Yupanqui Concha. Patterns and Determinants of Immigrants’ Internal Mobility: An Analysis of the Foreign Born in the Chilean Social Support Registry. Tesis, Magíster en Economía Agraria y Ambiental, Facultad de Agronomía e Ingeniería Forestal. Pontificia Universidad Católica de Chile. Santiago, Chile. 48 pp. This study describes the mobility patterns of foreign immigrants in Chile, beginning with their first location of residence and their later movements to other locations within the country. The study identifies how personal and territorial characteristics interact and correlate with individual location decisions, both when entering the country and in subsequent movements. Using panel data at the individual level from Chilean welfare agencies – the Ficha de Protección Social (FPS) and the Registro Social de Hogares (RSH) – for the period 2007-2018, an OLS and Logit models was estimated accounting for different aspects of the migration decision, the main results are as follows: (1) immigrants have a higher probability of inter-regional movement than native Chileans; (2) employment- related factors (such as the territorial percentage of the work force in mining) and income are the main drivers related to residence change; (3) the presence of the mining industry is key in the decision of the foreign-born to select their first location of residence in Chile, and in subsequent movements; (4) foreign-born living in Santiago have a higher probability to remain there compared to the native born; (5) among foreign born, women and younger people are more likely to move; and finally (6) that there is a positive though small relationship between internal movements and education.
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48 Lee mas

Numerical study of effect of wall heating conditions on heat transfer performance of internal cooling channel

Numerical study of effect of wall heating conditions on heat transfer performance of internal cooling channel

This paper investigates the impacts of wall heating conditions on heat transfer perform- ace for a rotating channel with one side smooth and one side roughened by 45 degree inclined ribs. Previous experimental and numerical studies for only ribbed wall heated case showed that rotation has significantly negative impact on heat transfer performance. In order to investigate this uncommon behaviour, RANS simulations were conducted un- der three different wall heating conditions in present study: ribbed wall heated, all walls heated and adiabatic conditions. Numerical results show that the uneven wall heating condtions has negligible impact on stationary case, however, it has a large influence on rotational cases, in both the heat transfer and the fluid field. This is because in rotating cases, uneven heatings result in different buoyancy effects on trailing and leading walls that alter the main flow velocity profile. As a consequence, also secondary flows and heat transfer performance are affected.
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12 Lee mas

Study of the dynamic performance of an Otto engine using mixtures two types of “Extra and Super” gasolines

Study of the dynamic performance of an Otto engine using mixtures two types of “Extra and Super” gasolines

The purpose of this study is to compare and examine the performance of an engine, using gasoline with 92 octanes (Super), 87 octanes (Extra) and two volume mixtures of these two types of gasoline, the first one had 50% of volume of each type, the second one had a volume value of 70% of Super with 30% of Extra. To evaluate the performance of the engine, a dynamometer was used to obtain the characteristics curves of power and torque, a gas analyzer was used to determine the level of emission of pollutant gases from the engine (CO, CO 2 , HC, y NOx), finally an
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13 Lee mas

Influence of the type of spark plug in the evaluation of the performance and emissions caused in an ignition engine

Influence of the type of spark plug in the evaluation of the performance and emissions caused in an ignition engine

This research was made in Cuenca at 2500 meters above sea level (masl), and it studied the influence of the use of different types of spark plugs in a spark-ignition engine on the mechanical performance of the engine, the pollutant emissions, and fuel consumption. Six types of spark plugs that are available in the national market are made of differ- ent materials, have different thermal properties, and have different electrode openings. In addition, the mechanical performance of the engines and their fuel consumption were evaluated through dynamometer testing. Moreover, the polluting emissions were measured under the static test protocol established by the NTE INEN 2203 and with an 11 km route test in urban areas and on highway based on the New European Driving Cycle. The research showed that a specific spark plug increases 16 % of the engine performance due to not only some factors such as less pollution, better cold behavior, lower fuel consumption, but also maintains the torque and power of the vehicle. In addition, this spark plug generates savings on maintenance and annual fuel consumption.
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11 Lee mas

Effect of water deficit on the agronomical performance and quality of  processing tomato

Effect of water deficit on the agronomical performance and quality of processing tomato

MANOVA biplots of main aroma logodor units in the year 2009 considering the factors irrigation a, cultivar b and the complete model with main factors and interaction c.. Circles represen[r]

37 Lee mas

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