scholarly journals A Model of Fuel Combustion Process in The Marine Reciprocating Engine Work Space Taking Into Account Load and Wear of Crankshaft-Piston Assembly and The Theory of Semi-Markov Processes

2016 ◽  
Vol 23 (3) ◽  
pp. 50-57 ◽  
Author(s):  
Jerzy Girtler

Abstract The article analyses the operation of reciprocal internal combustion engines, with marine engines used as an example. The analysis takes into account types of energy conversion in the work spaces (cylinders) of these engines, loads of their crankshaft-piston assemblies, and types of fuel combustion which can take place in these spaces during engine operation. It is highlighted that the analysed time-dependent loads of marine internal combustion engine crankshaft-piston assemblies are random processes. It is also indicated that the wear of elements of those assemblies resulting from their load should also be considered a random process. A hypothesis is formulated which explains random nature of load and the absence of the theoretically expected detonation combustion in engines supplied with such fuels as Diesel Oil, Marine Diesel Oil, and Heavy Fuel Oil. A model is proposed for fuel combustion in an arbitrary work space of a marine Diesel engine, which has the form of a stochastic four-state process, discrete in states and continuous in time. The model is based on the theory of semi-Markov processes.

Energies ◽  
2018 ◽  
Vol 11 (7) ◽  
pp. 1830 ◽  
Author(s):  
Moonchan Kim ◽  
Jungmo Oh ◽  
Changhee Lee

Compression ignition engines used as marine engines are the most efficient internal combustion engines. They are well-established products, and millions are already on the market. Water-in-MDO (marine diesel oil) emulsions are the best alternative fuel for compression ignition engines and can be utilised with the existing setup of 2.0 L automotive common rail direct injection (CRDI) engines. They have benefits for the simultaneous reduction of both NOx and smoke (black carbon). Furthermore, they have a significant impact on the improvement of combustion efficiency. Micro-explosions are the most important phenomenon of water-in-diesel emulsions inside an internal combustion engine chamber. They affect both the emission reduction and combustion efficiency improvements directly and indirectly in accordance with the brake mean effective pressure (BMEP) and rpm. Owing to the influence of micro-emulsions on the combustion and emissions of water-in-diesel emulsion fuel, the reduction ratios of NOx and smoke in a used engine are approximately 30% and 80%, respectively. The effect of the operating parameters on micro-emulsions is presented.


2011 ◽  
Vol 145 (2) ◽  
pp. 89-98
Author(s):  
Jacek RUDNICKI

The paper presents the extension of the method discussed in the literature of quantitative evaluation of operation on the example of a marine engine. According to this interpretation, the engine operation can be shown as a physical quantity. In this aspect, based on the main marine diesel engine an evaluation of the usefulness of this index for the description of the engine reliability related properties has been performed. Apart from the generally used reliability indexes, it seems purposeful to consider the engine operation (as well as its functional subsystems) in the evaluative way, so that it could be described by both energy and time. In this aspect, in the analysis the semi-Markov processes theory was used that allowed a description of the concept of the model of the engine deterioration process as a random one. The problem of the time of the first transition of the semi-Markov process to a subset of specified classes of states representing particular technical and reliability-related states of engine was described in detail.


2008 ◽  
Vol 45 (04) ◽  
pp. 191-193
Author(s):  
Wei Hai-jun ◽  
Wang Guo-you ◽  
Wang Xiao-rui

The purpose of this paper is to study the applicability of thermal processed fuel oil (hereafter called waste plastic disposal, or WPD) of diesel engines using low-quality fuel oil. In the experiment, stability of engine operation and components of exhaust gas, such as NOx and COx, were inspected from basic and applicable points of view. This paper illustrates a new test and result of WPD oil applied to marine diesel engines. In recent years, efforts have to be made to develop an advanced technique for recycling waste plastics in order to use scrapped plastics as fuel for diesel engines. It is very important and necessary for us to cope with the increasing calorific value and to satisfy the growing need of environment protection. The experimental fuel oil is obtained by a mixing of diesel oil, WPD, and water.


Author(s):  
E.T. Plaksina ◽  
A.B. Syritsky ◽  
A.S. Komshin

The article considers the main methods of internal combustion engine diagnostics. A method based on measuring the time intervals between the phases of the working cycle of the mechanism is described. An algorithm for measuring the time intervals from the formulation of the problem to the proof of the efficiency of this method on an internal combustion engine has been determined. The installation of the angle sensor on the crankshaft of the experimental bench engine VAZ 21126 is shown. The basis for the construction of a mathematical model of the crankshaft is presented and the main factors influencing its movement are identified. A criterion has been established according to which the misfire is determined most accurately. The results obtained can be used for developing diagnostic systems for internal combustion engines, as well as engines operating in extreme conditions, for example, beyond the Arctic Circle, on ships, etc.


2019 ◽  
Vol 22 (1) ◽  
pp. 341-348
Author(s):  
Nir Druker ◽  
Gideon Goldwine ◽  
Eran Sher

We propose here a new method to evaluate the mixture charge density inside the combustion chamber of an internal combustion engine. This is an important parameter that is needed to optimize the spark timing and the amount of fuel that is introduced to the cylinder at each cycle, thus optimizing the engine operation for higher power, lower brake-specific fuel consumption, or lower pollutants’ emission at any altitude/ambient conditions. The evaluation of the charge density is performed at each cycle (on a cycle-to-cycle basis) by using the voltage–current characteristics of the spark plug gap. This real-time evaluation method may save two of the present in-use temperature and pressure gages, thus considerably increasing the reliability of the propulsion unit. Owing to the expected higher system reliability and system simplicity, small unmanned aerial vehicles, as well as small automotive engines of various types, may significantly benefit from this proposed method. The method principles, rationale, and some preliminary results are presented.


2019 ◽  
Vol 2 (3) ◽  
pp. 121-128
Author(s):  
N. S. Sevryugina ◽  
A. S. Apatenko

Introduction: the factors determining the development trends of the machine-building industry on the example of modernization of the internal combustion engine are considered. The evaluation of the effectiveness of cooperation between manufacturers and the scientific potential of leading scientists in the development of designs of gas-diesel engines. The requirement of time of increase of ecology of internal combustion engines is proved, the reasons braking mass introduction of gas-diesel engines for transport and technological cars are revealed. The parameter of influence on the thermal load of the piston group in gaseous fuel is allocated. The estimation of constructive perfection of development of system of cooling of the piston of the engine is given. The effects of increased temperature on individual parts of the piston in the form of scrapes, chips, causing failure of the internal combustion engine as a whole are shown. The influence of engine oil quality on the engine operation is revealed. It is proposed to Supplement the design of the internal combustion engine with an oil level control device, developed an algorite and a software product for calculating the residual life of the engine oil on key parameters, with the establishment of the term of their replacement.Methods: the study is based on the analysis of the works of leading domestic and foreign scientists in the field of improving the design of power equipment. The theoretical and methodological basis of the study was the system approach, methods of mathematical analysis, reliability theory, analytical and statistical processing of results.Results and discussion: the theoretical justification for the increased thermal load of piston in a gas-diesel engine, justifies the addition of the construction device control engine oil level and consideration of the resource and replacement intervals for the parameters of the actual physical and chemical condition, using the database presented in the software product.Conclusion: operation of gas-diesel engines requires from the operator more strict control over the temperature regime of the engine, the condition of the engine oil and the efficiency of the engine oil, the proposed solutions will allow to assess the quality of the engine oil in real time and to carry out its replacement according to the actual condition, which will ensure.


2015 ◽  
Vol 137 (6) ◽  
Author(s):  
Shahrokh Etemad ◽  
Benjamin D. Baird ◽  
Sandeep Alavandi

Development of technologies that allow small, high power density engines such as unmanned aerial vehicles (UAV), unmanned marine vehicles (UMV), and unmanned ground vehicles (UGV) to operate on single logistic fuel such as JP-8 is one of government goals. To advance this goal, a lightweight, compact, and retrofit capable ignition source is critical. Compared to standard spark igniters and noncatalytic glow plugs, the use of catalytic glow plugs will provide benefits of lower required compression ratio, improved igniter life, reduced electrical energy requirements, and overall reduction in system weight and size. Experimental testing demonstrated a significant increase in surface temperature (160+ °C) with impingement of a fuel spray compared to a conventional glow plug with engine testing demonstrating the use of catalyst allows stable engine operation at reduced power requirements. Computational analysis was performed to provide insight into the catalyst behavior. Analytical studies suggested increased stability due to both heat release due to exothermic catalytic reaction and production of reactive species. This technology would allow high power density engines to use heavy fuels, while potentially reducing electric power supply and engine complexity and weight, both of which would allow greater range and/or payload capacity. This paper discusses the feasibility of advanced igniters technology as an enabling component for the use of heavy fuels in small, high power density internal combustion engines. The paper presents and discusses analytical investigation, experimental test results, and durability testing data in an internal combustion engine environment.


2019 ◽  
Vol 9 (22) ◽  
pp. 4842 ◽  
Author(s):  
Ho Lung Yip ◽  
Aleš Srna ◽  
Anthony Chun Yin Yuen ◽  
Sanghoon Kook ◽  
Robert A. Taylor ◽  
...  

A paradigm shift towards the utilization of carbon-neutral and low emission fuels is necessary in the internal combustion engine industry to fulfil the carbon emission goals and future legislation requirements in many countries. Hydrogen as an energy carrier and main fuel is a promising option due to its carbon-free content, wide flammability limits and fast flame speeds. For spark-ignited internal combustion engines, utilizing hydrogen direct injection has been proven to achieve high engine power output and efficiency with low emissions. This review provides an overview of the current development and understanding of hydrogen use in internal combustion engines that are usually spark ignited, under various engine operation modes and strategies. This paper then proceeds to outline the gaps in current knowledge, along with better potential strategies and technologies that could be adopted for hydrogen direct injection in the context of compression-ignition engine applications—topics that have not yet been extensively explored to date with hydrogen but have shown advantages with compressed natural gas.


Energies ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3734
Author(s):  
Javier Monsalve-Serrano ◽  
Giacomo Belgiorno ◽  
Gabriele Di Blasio ◽  
María Guzmán-Mendoza

Notwithstanding the policies that move towards electrified powertrains, the transportation sector mainly employs internal combustion engines as the primary propulsion system. In this regard, for medium- to heavy-duty applications, as well as for on- and off-road applications, diesel engines are preferred because of the better efficiency, lower CO2, and greater robustness compared to spark-ignition engines. Due to its use at a large scale, the internal combustion engines as a source of energy depletion and pollutant emissions must further improved. In this sense, the adoption of alternative combustion concepts using cleaner fuels than diesel (e.g., natural gas, ethanol and methanol) presents a viable solution for improving the efficiency and emissions of the future powertrains. Particularly, the methane–diesel dual-fuel concept represents a possible solution for compression ignition engines because the use of the low-carbon methane fuel, a main constituent of natural gas, as primary fuel significantly reduces the CO2 emissions compared to conventional liquid fuels. Nonetheless, other issues concerning higher total hydrocarbon (THC) and CO emissions, mainly at low load conditions, are found. To minimize this issue, this research paper evaluates, through a new and alternative approach, the effects of different engine control parameters, such as rail pressure, pilot quantity, start of injection and premixed ratio in terms of efficiency and emissions, and compared to the conventional diesel combustion mode. Indeed, for a deeper understanding of the results, a 1-Dimensional spray model is used to model the air-fuel mixing phenomenon in response to the variations of the calibration parameters that condition the subsequent dual-fuel combustion evolution. Specific variation settings, in terms of premixed ratio, injection pressure, pilot quantity and combustion phasing are proposed for further efficiency improvements.


Author(s):  
V. L. Yusha ◽  
◽  
G. I. Chernov ◽  
I. D. Obukhov ◽  
O. G. Bessonov ◽  
...  

This paper present an assessment of the energy efficiency of various combinations of piston stages of an internal combustion engine, a compressor, and a Rankine engine as part of piston motor-compressor units based on modernized marine diesel engines. An eight-cylinder single-row diesel engine 8Ch23/30-1 is chosen as the object of research, the base of which is used as a single platform for creating powertechnology units for various purposes and power. The proposed variants for converting the original engine allow, with minimal costs for the development of design and manufacturing technology, to create gas engine compressor units with reduced fuel consumption and improved weight and size characteristics in comparison with the known mobile compressor stations driven by diesel internal combustion engines. In the paper, on the basis of the developed mathematical models of working processes, the possibility of joint operation of diesel cylinders with piston expanders of the Rankine cycle and one or more stages of a piston compressor is assessed. Various possible combinations of diesel cylinders, compressor cylinders and expander cylinders are considered, as well as the dependences of engine power and compressor performance depending on the number of compressor stages and the number of diesel power cylinders used.


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