scholarly journals REGRESSION EQUATIONS FOR CALCULATING THE SOLUBILITY OF HYDROGEN IN LIQUID FUELS

2019 ◽  
Vol 85 (12) ◽  
pp. 110-116
Author(s):  
Lev Leybovych ◽  
Yurii Yevstigneyev
Keyword(s):  
Internal Combustion Engines ◽  
Average Molecular Weight ◽  
Heat Engine ◽  
Combustion Process ◽  
Hydrocarbon Composition ◽  
Liquid Fuels ◽  
Regression Equations ◽  
Heat Engines ◽  
Hydrogen Mixtures ◽  
Heavy Fuels

The efficiency of combustion of liquid fuels in heat engines is determined by their hydrocarbon composition. The rate of combustion and the completeness of combustion depend on  the  hydrocarbon composition of the fuel. One of the ways to increase the efficiency of combustion of fuel is to use fuel-hydrogen mixtures. The use of such mixtures gives prerequisites for low-temperature self-ignition of fuel droplets (about 590 °C). Preheating of the fuel gives the possibility of "explosive" combustion with increasing of the temperature up to 2500 K in 0.02 –. 0.04 ms. This leads to the intensification of heavy fuel combustion. The use of fuel-hydrogen mixtures allows to obtain a low level of harmful emissions with flue gases and to reduce emissions: CO and CH – not less than 15%, CO2 – not less than 20%. A promising direction for the creation of such mixtures is the direct dissolution of hydrogen in liquid fuel. This simplifies the flow of the fuel-hydrogen mixture into the combustion chamber of the heat engine or into the cylinders of the internal combustion engines. Analysis of previous studies showed the possibility of obtaining a single form of regression dependence for calculations of the dissolution of hydrogen in liquid fuels. The processing of the literature data and the results of our own research gave a set of regression equations for calculating the solubility of hydrogen in liquid fuels: gas, diesel, fuel oil, LVGO, HVGO, GDAR, ABVB. The obtained regression dependencies show that with increasing average molecular weight the solubility of hydrogen in the fuel decreases. These regression dependencies make it possible to obtain baseline data for the design of fuel systems for supplying fuel and hydrogen mixtures to combustion chambers of heat engines. Studies of hydrogen-diesel have shown a decrease in the flash fuel temperature by 10 – 15 oC by comparison with pure fuel. For heavy fuels, this level of reduction of the fuel round is not sufficient. Therefore, it is necessary to conduct further studies on the intensification of the process of dissolution of hydrogen in heavy fuels. This will significantly reduce energy costs for the organization of the combustion process.

scholarly journals On board recognition of different fuels in SI engines with the use of dimensional and non-dimensional vibration signal parameters

2009 ◽  
Vol 136 (1) ◽  
pp. 69-75
Author(s):  
Paweł FABIŚ ◽  
Bartosz FLEKIEWICZ ◽  
Marek FLEKIEWICZ
Keyword(s):  
Alternative Fuels ◽  
Internal Combustion Engines ◽  
Vibration Signal ◽  
Spark Ignition Engine ◽  
Combustion Noise ◽  
Liquid Fuels ◽  
Cylinder Block ◽  
Gaseous Fuels ◽  
Engine Vibration ◽  
Hydrogen Mixtures

Gaseous fuels such as natural gas and propane butane mixtures are currently the most popular fuels for dual fuel internal combustion engines. Gaseous fuels are more resistant to knocking than conventional liquid fuels they mix better with air. There have been many published works on the use of gaseous fuels but the problem of the combustion noise, as a very important source of acoustic discomfort is not getting enough attention. Combustion noise occurs in a direct and indirect form. It is transmitted throughout the engine block as a vibration at a different spectrum of frequencies. In this study an attempt has been made to correlate the combustion noise with the operating parameters of an engine fueled with LPG, CNG and CNG-hydrogen mixtures as compared to petrol fueled engine. Signals of multiple resonance in the combustion chamber and corresponding vibration signals of the cylinder block of engine have been considered for one combustion cycle. A four cylinder, 1.6 dm3 spark-ignition engine converted to run on LPG, CNG and CNG-hydrogen mixtures has been tested in the project. A well known diagnostic parameter was used for comparison of the engine noise for its operation on gasoline and alternative fuels. A new non-dimensional indicator has also been proposed for the engine vibration estimation purposes the Increase Wavelet Ratio C’ab, precisely described in the paper.

Extraction and Determination of Physico-chemical Properties of Oil from Watermelon Seeds (Citrullus lanatus L) to Use in Internal Combustion Engines

2017 ◽  
Vol 68 (11) ◽  
pp. 2676-2681
Author(s):  
Mihaela Gabriela Dumitru ◽  
Dragos Tutunea
Keyword(s):  
Fatty Acid ◽  
Internal Combustion Engines ◽  
Fossil Fuels ◽  
Citrullus Lanatus ◽  
Combustion Process ◽  
Chemical Properties ◽  
Physico Chemical ◽  
Mean Diameter ◽  
Geometrical Mean ◽  
Reduction Of Nox

The purpose of this work was to investigate the physicochemical properties of watermelon seeds and oil and to find out if this oil is suitable and compatible with diesel engines. The results showed that the watermelon seeds had the maximum length (9.08 mm), width (5.71mm), thickness (2.0 mm), arithmetic mean diameter (5.59 mm), geometrical mean diameter (4.69 mm), sphericity (51.6%), surface area (69.07), volume 0.17 cm3 and moisture content 5.4%. The oil was liquid at room temperature, with a density and refractive index of 0.945 and 1.4731 respectively acidity value (1.9 mgNaOH/g), free fatty acid (0.95 mgNaOH), iodine value (120 mgI2/100g), saponification value (180 mgKOH/g), antiradical activity (46%), peroxide value (7.5 mEqO2/Kg), induction period (6.2 h), fatty acid: palmitic acid (13.1%), stearic acid (9.5 %), oleic acid (15.2 %) and linoleic acid (61.3%). Straight non food vegetable oils can offer a solution to fossil fuels by a cleaner burning with minimal adaptation of the engine. A single cylinder air cooled diesel engine Ruggerini RY 50 was used to measure emissions of various blends of watermelon oil (WO) and diesel fuel (WO10D90, WO20D80, WO30D70 and WO75D25). The physic-chemical properties of the oil influence the combustion process and emissions leading to the reduction of NOX and the increase in CO, CO2 and HC.

scholarly journals Comparison of Diesel Engine Vibroacoustic Properties Powered by Bio and Standard Fuel

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1478
Author(s):  
Radoslaw Wrobel ◽  
Gustaw Sierzputowski ◽  
Zbigniew Sroka ◽  
Radostin Dimitrov
Keyword(s):  
Alternative Fuels ◽  
Internal Combustion Engines ◽  
Combustion Process ◽  
Significant Other ◽  
Engine Torque ◽  
Engine Model ◽  
Vehicle Operation ◽  
History Of ◽  
Profile Changes ◽  
The Time Domain

Alternative fuels appeared soon after the first internal combustion engines were designed. The history of alternative fuels is basically as long as the history of the automotive industry. Initially, fuels whose physicochemical properties allowed for a change in parameters of the combustion process in order to achieve greater efficiency and reliability were searched for. Nowadays, there are significantly more variables; in addition to the above mentioned parameters, alternative fuels are being sought that will ensure environmental protection during vehicle operation and improve the ergonomics of use. This article outlines the results of the authors’ own comparative tests of vibrations of a vibroacoustic character. Based on a popular engine model, the vibration–acoustic responses of a system powered by two types of fuel, namely, diesel and biodiesel (B10), are compared. The research consists of comparing vibrations in both time and frequency domains. In the case of the time domain, the evaluation was performed with vibrations as a function of engine torque and speed. In the case of frequency analysis, the focus was on changes in the frequency response for the tested fuels. The research shows that the profile of vibroacoustic vibrations changes in the case of biodiesel power supply in relation to standard fuel. The vibration profile changes significantly as a function of speed and only slightly in relation to the engine load. The results presented in this article show different vibroacoustic responses of an engine powered by diesel and biodiesel; the change is minor for lower speeds but significant (other harmonics are dominant) for higher speeds (changes in the dominant harmonic magnitude of up to 10% at a crankshaft speed of 3000 rpm).

scholarly journals Modeling and Performance Optimization of an Irreversible Two-Stage Combined Thermal Brownian Heat Engine

Entropy ◽  
2021 ◽  
Vol 23 (4) ◽  
pp. 419
Author(s):  
Congzheng Qi ◽  
Zemin Ding ◽  
Lingen Chen ◽  
Yanlin Ge ◽  
Huijun Feng
Keyword(s):  
Power Output ◽  
Performance Optimization ◽  
External Load ◽  
Thermal Contact ◽  
Heat Engine ◽  
Design Parameters ◽  
Load Effect ◽  
Heat Engines ◽  
Heat Leakage ◽  
Steady Current

Based on finite time thermodynamics, an irreversible combined thermal Brownian heat engine model is established in this paper. The model consists of two thermal Brownian heat engines which are operating in tandem with thermal contact with three heat reservoirs. The rates of heat transfer are finite between the heat engine and the reservoir. Considering the heat leakage and the losses caused by kinetic energy change of particles, the formulas of steady current, power output and efficiency are derived. The power output and efficiency of combined heat engine are smaller than that of single heat engine operating between reservoirs with same temperatures. When the potential filed is free from external load, the effects of asymmetry of the potential, barrier height and heat leakage on the performance of the combined heat engine are analyzed. When the potential field is free from external load, the effects of basic design parameters on the performance of the combined heat engine are analyzed. The optimal power and efficiency are obtained by optimizing the barrier heights of two heat engines. The optimal working regions are obtained. There is optimal temperature ratio which maximize the overall power output or efficiency. When the potential filed is subjected to external load, effect of external load is analyzed. The steady current decreases versus external load; the power output and efficiency are monotonically increasing versus external load.

scholarly journals Combustion Thermodynamics of Ethanol, n-Heptane, and n-Butanol in a Rapid Compression Machine with a Dual Direct Injection (DDI) Supply System

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2729
Author(s):  
Ireneusz Pielecha ◽  
Sławomir Wierzbicki ◽  
Maciej Sidorowicz ◽  
Dariusz Pietras
Keyword(s):  
Heat Release ◽  
Combustion Chamber ◽  
Internal Combustion Engines ◽  
Direct Injection ◽  
Combustion Process ◽  
Combustion Efficiency ◽  
Injection System ◽  
Rapid Compression Machine ◽  
Process Indicators ◽  
Rapid Compression

The development of internal combustion engines involves various new solutions, one of which is the use of dual-fuel systems. The diversity of technological solutions being developed determines the efficiency of such systems, as well as the possibility of reducing the emission of carbon dioxide and exhaust components into the atmosphere. An innovative double direct injection system was used as a method for forming a mixture in the combustion chamber. The tests were carried out with the use of gasoline, ethanol, n-heptane, and n-butanol during combustion in a model test engine—the rapid compression machine (RCM). The analyzed combustion process indicators included the cylinder pressure, pressure increase rate, heat release rate, and heat release value. Optical tests of the combustion process made it possible to analyze the flame development in the observed area of the combustion chamber. The conducted research and analyses resulted in the observation that it is possible to control the excess air ratio in the direct vicinity of the spark plug just before ignition. Such possibilities occur as a result of the properties of the injected fuels, which include different amounts of air required for their stoichiometric combustion. The studies of the combustion process have shown that the combustible mixtures consisting of gasoline with another fuel are characterized by greater combustion efficiency than the mixtures composed of only a single fuel type, and that the influence of the type of fuel used is significant for the combustion process and its indicator values.

scholarly journals Learning the best nanoscale heat engines through evolving network topology

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Yuto Ashida ◽  
Takahiro Sagawa
Keyword(s):  
Network Topology ◽  
Heat Engine ◽  
Search Space ◽  
Single Electron ◽  
Thermodynamic Efficiency ◽  
Full Potential ◽  
Thermal Systems ◽  
Nanoscale Systems ◽  
Heat Engines ◽  
Many Body Interactions

AbstractThe quest to identify the best heat engine has been at the center of science and technology. Considerable studies have so far revealed the potentials of nanoscale thermal machines to yield an enhanced thermodynamic efficiency in noninteracting regimes. However, the full benefit of many-body interactions is yet to be investigated; identifying the optimal interaction is a hard problem due to combinatorial explosion of the search space, which makes brute-force searches infeasible. We tackle this problem with developing a framework for reinforcement learning of network topology in interacting thermal systems. We find that the maximum possible values of the figure of merit and the power factor can be significantly enhanced by electron-electron interactions under nondegenerate single-electron levels with which, in the absence of interactions, the thermoelectric performance is quite low in general. This allows for an alternative strategy to design the best heat engines by optimizing interactions instead of single-electron levels. The versatility of the developed framework allows one to identify full potential of a broad range of nanoscale systems in terms of multiple objectives.

scholarly journals Action and Entropy in Heat Engines: An Action Revision of the Carnot Cycle

Entropy ◽  
2021 ◽  
Vol 23 (7) ◽  
pp. 860
Author(s):  
Ivan R. Kennedy ◽  
Migdat Hodzic
Keyword(s):  
Heat Engine ◽  
Working Fluid ◽  
Field Energy ◽  
Carnot Cycle ◽  
Gibbs Potential ◽  
Atmospheric Gases ◽  
Temperature Dependent ◽  
Expansion Phase ◽  
Heat Engines ◽  
The Difference

Despite the remarkable success of Carnot’s heat engine cycle in founding the discipline of thermodynamics two centuries ago, false viewpoints of his use of the caloric theory in the cycle linger, limiting his legacy. An action revision of the Carnot cycle can correct this, showing that the heat flow powering external mechanical work is compensated internally with configurational changes in the thermodynamic or Gibbs potential of the working fluid, differing in each stage of the cycle quantified by Carnot as caloric. Action (@) is a property of state having the same physical dimensions as angular momentum (mrv = mr2ω). However, this property is scalar rather than vectorial, including a dimensionless phase angle (@ = mr2ωδφ). We have recently confirmed with atmospheric gases that their entropy is a logarithmic function of the relative vibrational, rotational, and translational action ratios with Planck’s quantum of action ħ. The Carnot principle shows that the maximum rate of work (puissance motrice) possible from the reversible cycle is controlled by the difference in temperature of the hot source and the cold sink: the colder the better. This temperature difference between the source and the sink also controls the isothermal variations of the Gibbs potential of the working fluid, which Carnot identified as reversible temperature-dependent but unequal caloric exchanges. Importantly, the engine’s inertia ensures that heat from work performed adiabatically in the expansion phase is all restored to the working fluid during the adiabatic recompression, less the net work performed. This allows both the energy and the thermodynamic potential to return to the same values at the beginning of each cycle, which is a point strongly emphasized by Carnot. Our action revision equates Carnot’s calorique, or the non-sensible heat later described by Clausius as ‘work-heat’, exclusively to negative Gibbs energy (−G) or quantum field energy. This action field complements the sensible energy or vis-viva heat as molecular kinetic motion, and its recognition should have significance for designing more efficient heat engines or better understanding of the heat engine powering the Earth’s climates.

scholarly journals Effects of Catalysts on Emissions of Pollutants from Combustion Processes of Liquid Fuels

2014 ◽  
Vol 13 (2) ◽  
pp. 5-17
Author(s):  
Agnieszka Bok ◽  
Joanna Guziałowska-Tic ◽  
Wilhelm Jan Tic
Keyword(s):  
Combustion Process ◽  
Combustion Products ◽  
Organometallic Complexes ◽  
Liquid Fuels ◽  
Motor Fuels ◽  
Harmful Emissions ◽  
Fuel Oils ◽  
Sulphur Oxides ◽  
Dynamic Growth ◽  
Combustion Processes

Abstract The dynamic growth of the use of non-renewable fuels for energy purposes results in demand for catalysts to improve their combustion process. The paper describes catalysts used mainly in the processes of combustion of motor fuels and fuel oils. These catalysts make it possible to raise the efficiency of oxidation processes simultanously reducing the emission of pollutants. The key to success is the selection of catalyst compounds that will reduce harmful emissions of combustion products into the atmosphere. Catalysts are introduced into the combustion zone in form of solutions miscible with fuel or with air supplied to the combustion process. The following compounds soluble in fuel are inclused in the composition of the described catalysts: organometallic complexes, manganese compounds, salts originated from organic acids, ferrocen and its derivatives and sodium chloride and magnesium chloride responsible for burning the soot (chlorides). The priority is to minimize emissions of volatile organic compounds, nitrogen oxides, sulphur oxides, and carbon monoxide, as well as particulate matter.

scholarly journals Determination of Combustion Process Model Parameters in Diesel Engine with Variable Compression Ratio

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Saša Milojević ◽  
Radivoje Pešić
Keyword(s):  
Diesel Engine ◽  
Compression Ratio ◽  
Process Model ◽  
Internal Combustion Engines ◽  
Combustion Process ◽  
Exhaust Emission ◽  
Model Parameters ◽  
Connecting Rod ◽  
Variable Compression Ratio ◽  
Variable Compression

Compression ratio has very important influence on fuel economy, emission, and other performances of internal combustion engines. Application of variable compression ratio in diesel engines has a number of benefits, such as limiting maximal in cylinder pressure and extended field of the optimal operating regime to the prime requirements: consumption, power, emission, noise, and multifuel capability. The manuscript presents also the patented mechanism for automatic change engine compression ratio with two-piece connecting rod. Beside experimental research, modeling of combustion process of diesel engine with direct injection has been performed. The basic problem, selection of the parameters in double Vibe function used for modeling the diesel engine combustion process, also performed for different compression ratio values. The optimal compression ratio value was defined regarding minimal fuel consumption and exhaust emission. For this purpose the test bench in the Laboratory for Engines of the Faculty of Engineering, University of Kragujevac, is brought into operation.

Effect of Engine Operating Parameters on Combustion and Emission Characteristics

1992 ◽  
Author(s):  
Jiang Lu ◽  
Ashwani K. Gupta ◽  
Eugene L. Keating
Keyword(s):  
Internal Combustion Engine ◽  
Combustion Chamber ◽  
Internal Combustion Engines ◽  
Combustion Engine ◽  
Combustion Process ◽  
Pressure Rise ◽  
Internal Combustion ◽  
Operating Parameters ◽  
Emission Characteristics ◽  
Pollutants Emission

Abstract Numerical simulation of flow, combustion, heat release rate and pollutants emission characteristics have been obtained using a single cylinder internal combustion engine operating with propane as the fuel. The data are compared with experimental results and show excellent agreement for peak pressure and the rate of pressure rise as a function of crank angle. The results obtained for NO and CO are also found to be in good agreement and are similar to those reported in the literature for the chosen combustion chamber geometry. The results have shown that both the combustion chamber geometry and engine operating parameters affects the flame growth within the combustion chamber which subsequently affects the pollutants emission levels. The code employed the time marching procedure and solves the governing partial differential equations of multi-component chemically reacting fluid flow by finite difference method. The numerical results provide a cost effective means of developing advanced internal combustion engine chamber geometry design that provides high efficiency and low pollution levels. It is expected that increased computational tools will be used in the future for enhancing our understanding of the detailed combustion process in internal combustion engines and all other energy conversion systems. Such detailed information is critical for the development of advanced methods for energy conservation and environmental pollution control.

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