scholarly journals METHOD OF NON-GRADIENT MINIMIZATION POWELL'64 IN THE TASKS OF MONITORING OPERATION OF MARINE DIESEL ENGINES

Author(s):  
Alexey Valerievich Yeryganov ◽  
Vladyslav Olegovych Maulevych ◽  
Roman Anatolievich Varbanets ◽  
Evgeniy Ivanovich Zholtikov ◽  
Valeriy Georgievitch Ivanovskiy ◽  
...  

The article touches upon the possibility of using the method of gradientless n-parametric minimization of Powell'64 in tasks of monitoring the working process of marine diesel engines. There is given an example of finding a global minimum of the Rosenbrock test function. Using the Powell'64 method, the Least-squares functionals in the synchronization and modelling tasks of compression-expansion curves in the working cylinder are minimized. The calculation results of data synchronization for low-speed two-stroke and medium-speed four-stroke marine diesel engines are shown. The synchronization problem can be solved in terms of equation P' = 0 derived for the sector from compression starting to combustion starting in the cylinder. The selection of the boundary conditions for simulation is shown. The advantage of Powell’64 method is its high efficiency for quadratic functionals. As opposed to gradient methods, the Powell'64 method does not require calculating derivatives and is universal for minimizing complex nonlinear general functionals. The original author's algorithm of data synchronization by analyzing the indicator diagrams using the Powell'64 method has been applied in the latest versions of monitoring systems of D4.0H marine diesel engine.

2018 ◽  
pp. 90-103
Author(s):  
R.A. Varbanets ◽  
E.V. Belousov ◽  
A.V. Yeryganov ◽  
V.O. Maulevych ◽  
N.I. Aleksandrovskaya ◽  
...  

The article touches upon the possibility of using the method of gradientless n-parametric minimization of Powell'64 in tasks of monitoring the working process of marine diesel engines. There is given an example of finding a global minimum of the Rosenbrock test function. Using the Powell'64 method, the Least-squares functionals in the synchronization and modelling tasks of compression-expansion curves in the working cylinder are minimized. The calculation results of data synchronization for low-speed two-stroke and medium-speed four-stroke marine diesel engines are shown. The synchronization problem can be solved in terms of equation P' = 0 derived for the sector from compression starting to combustion starting in the cylinder. The selection of the boundary conditions for simulation is shown. The advantage of Powell’64 method is its high efficiency for quadratic functionals. As opposed to gradient methods, the Powell'64 method does not require calculating derivatives and is universal for minimizing complex nonlinear general functionals. The original author's algorithm of data synchronization by analyzing the indicator diagrams using the Powell'64 method has been applied in the latest versions of monitoring systems of D4.0H marine diesel engine.


2018 ◽  
pp. 9-18
Author(s):  
Роман Анатолійович Варбанець ◽  
Євген Вікторович Белоусов ◽  
Олексій Валерійович Єриганов ◽  
Владислав Іванович Кирнац ◽  
Владислав Олегович Маулевич ◽  
...  

The possibility of using the gradientless n-parametric minimization of Powell'64 in the tasks of monitoring the workflow of ship diesel engines is considered. Monitoring the workflow of ship diesel engines includes the problem of cyclical analysis of indicator diagrams in the working cylinders. The problem of data synchronization should be solved - the transfer of pressure charts from the time function to an angle of crankshaft rotation function. It is shown that the hardware detection of the crankshaft rotation phases applying pick-up sensors configured in statics will have errors when the engine is under load. The synchronization task should be solved with the help of an algorithm by analyzing the indicator diagram in real time. Examples of the search for a global minimum of the Rosenbrock test function are given. Applying the Powell'64 method, least square method functionals are minimized in problems of synchronization and modeling of compression-expansion curves in the working cylinder. Cases of data synchronization calculation for low-speed two-stroke and mid-envelope four-stroke marine diesel engines are shown. Taking into account the assumptions made in practice, it was shown that at the point of maximum pressure growth rate on the compression curve, the cylinder volume above the piston can be calculated applying the known geometric dimensions of the cylinder and the P and dP/dφ values obtained from the indicator diagram. The next step is to calculate the first approximation of the position of the top dead center of the piston, and the application of the digital filters is necessary. Finally, the synchronization problem is solved on the basis of the equation dP/dφ = 0, compiled for the section from the start of compression to the start of combustion in the cylinder. The selection of boundary conditions for modeling is shown. The advantage of applying the Powell'64 method is its high efficiency for quadratic functionals. Unlike gradient methods, the Powell'64 method does not require the calculation of derivatives and is universal to minimize complex nonlinear functionals of a general form. The original author's algorithm for data synchronization by analyzing indicator diagrams, which applies the Powell'64 method, is used in the latest versions of the D4.0HT marine diesel engine monitoring systems


Author(s):  
Л.Б. Леонтьев ◽  
Н.П. Шапкин ◽  
А.Л. Леонтьев ◽  
В.Н. Макаров ◽  
А.В. Арон

Повышение долговечности трибосопряжений судовых дизелей, определяющих их ресурс, представляет собой актуальнейшую проблему, обусловленную как безопасностью мореплавания, так и экономическими факторами. Основной причиной отказов коленчатых валов двигателей, определяющих необходимость капитального ремонта, является износ шеек. Решение проблемы повышения износостойкости и, соответственно, долговечности связано с применением трибоактивных присадок в смазку. Несмотря на глубокие и обстоятельные исследования в области применения органо-неорганических материалов для использования в качестве присадок в моторное масло для повышения долговечности трибоузлов осуществить выбор оптимального материала для конкретных условий практически невозможно, так как исследования выполнены для различных условий эксплуатации и по различным методикам. Цель работы – разработка триботехнической присадки к моторным маслам, обеспечивающей повышение надежности и эффективности технической эксплуатации судовыхсреднеоборотных дизелей путем формирования тонкопленочного металлокерамического покрытия на поверхностях трения стальных деталей трибоузлов, позволяющего получить оптимальный комплекс параметров материала износостойкого покрытия. В работе представлены исследования эксплуатационных свойств присадок в моторное масло 17 органо-неорганических триботехнических материалов 4 групп — природные и искусственные полимеры, из которых были изготовлены свыше 20 композиций и композитов. Установлено, что наиболее перспективным является использование нанокомпозитов на основе вермикулита, модифицированного кислотой, в качестве присадок в моторное масло, так как они обладают минимальными коэффициентом трения при граничной смазке (0,007–0,014) а также высокой износостойкостью стали 40Х и обеспечивают минимальную величину скорости изнашивания вкладыша подшипника, благодаря чему повышается ресурс трибосопряжения более, чем в 3 раза, и соответственно снижаются эксплуатационные расходы. Increasing the durability of the tribo-couplings of marine diesel engines, which determine their resource, is an urgent problem due to both the safety of navigation and economic factors. The main reason for engine crankshafts failures, which determine the need for major repairs, is the wear of the necks. The solution to the problem of increasing wear resistance and, accordingly, durability is associated with the use of triboactive additives in the lubricant. Despite in-depth and thorough research in the field of application of organo-inorganic materials for use as additives in engine oil to increase the durability of tribo-nodes, it is almost impossible to choose the optimal material for specific conditions, since the studies were carried out for various operating conditions and according to various methods. The purpose of the work is to develop a tribotechnical additive to motor oils that provides an increase in the reliability and efficiency of technical operation of medium-speed marine diesel engines by forming a thin-film metal-ceramic coating on the friction surfaces of steel parts of tribo-nodes, which allows to obtain an optimal set of parameters of the wear-resistant coating material. The paper presents studies of the operational properties of additives in engine oil of 17 organo-inorganic tribotechnical materials of 4 groups — natural and artificial polymers, from which more than 20 compositions and composites were made. It has been established that the most promising is the use of nanocomposites based on vermiculite modified with acid as additives in engine oil, since they have a minimum coefficient of friction with boundary lubrication (0.007-0.014) as well as high wear resistance of 40X steel and provide a minimum wear rate of the bearing liner, thereby increasing the tribo-tension life by more than 3 times, and, accordingly, operating costs are reduced.


2013 ◽  
Vol 588 ◽  
pp. 149-156 ◽  
Author(s):  
Stanisław Polanowski ◽  
Rafał Pawletko ◽  
Kazimierz Witkowski

Analysis of the indicator diagram is the basis of technical state evaluation of marine diesel engines. The indicator diagram contains a large amount of diagnostic information. A major problem for the diagnostic use of the indicator diagram is the pressure sensor location. Indicator channel and valve may introduce significant distortions in the resulting pressure. The paper presents results of research conducted on the medium speed laboratory engine Al 25/30. Pressure measurement (indication) was made by the sensor placed directly in the cylinder (instead of starting air valve), before the indicator valve (with special Kistler adapter) and on the indicator valve. Distortion of heat release characteristics for the sensor placed on the indicator valve is important, but it is estimated that diagnostic information is not erased. For medium speed engines is to be expected the use of a portable pressure sensors placed on the indicator valve. For this reason, further research is needed to assess the impact of channels and valves on different cylinders. During the research the course of heat release rate q and the heat released Q were determined. The curve of heat release rate q is a full equivalent to fuel injection pressure curve in the fuel pipes. It allows identification of the failure of the injection system. The curve of Q allows such determination and assessment of internal efficiency of the cylinder.


Author(s):  
Hyoung-Keun Park ◽  
Sang-Hak Ghal ◽  
Tae-Hyung Park ◽  
Yong-Hee Ahn ◽  
Sung-Hyeok Kim

Straight vegetable oil (SVO) fuels such as palm oil, animal fat oil and waste vegetable oil were tested as fuels in a single-cylinder diesel engine to evaluate applicability to medium-speed diesel engines. Fuel-related properties of the SVO were assessed and compared with conventional marine diesel fuel oil (MDO). The total acid number (TAN) of the SVO fuels changed during a short interval in a drying oven which heated the SVO fuels to 170 degrees Celsius for several weeks. The SVO have not gone rancid any further after reaching limit. And the TAN of the SVO fuels was not related to corrosion of the parts. The SVO fuels needed to be heated to an appropriate temperature to use as fuel of the engine since the SVO fuels are more viscous than conventional diesel fuels. Both the injection period and the injection pressure increased due to low heating values of the SVO fuels. By the same token, fuel oil consumption increased over 10%. The overall exhaust emissions were lower with the SVO fuels, but NOx emission was as much as MDO at the higher loads.


Author(s):  
Oleg Petrovich Shuraev

The article summarizes the results of heat engineering tests of diesels used in the educational process of Volga State University of Water Transport and its branches. Although the test goals were different in each case, the indicator diagrams of the working process in each cylinder were recorded in the course of the tests. Analysis of indicator diagrams helped to determine the indicator power of the engine in each case. By comparing the indicator parameters with the corresponding effective ones there was performed the estimation of the mechanical efficiency of each engine at different speeds of rotation of the crankshaft. The studies were carried out on engines of brands 6NVD48AU, 6L275RrII/PN, 8NVD36U, 6L160PNS. It was found that in almost all cases, mechanical losses included fan losses in load devices and friction losses in their bearings. The concept of a screw characteristic is considered. A graph of the propeller characteristics in relative units for various types of engines is built. It is noted that it is very difficult to set a specific value of the crankshaft speed required for testing, the actual points will be close to the theoretical ones, shifting along the helical characteristic. An algorithm for testing and processing the results is presented. There have been analyzed the dependences covered in literature (analytical and statistical) for determining the mechanical efficiency.


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