scholarly journals Structural Modifications for Improving the Tribological Properties of the Cylinder Unit in Two-stroke Slow Speed Marine Diesel Engines

2012 ◽  
Vol 1 (2) ◽  
pp. 89-95 ◽  
Author(s):  
Branko Lalić ◽  
Ivan Komar ◽  
Đorđe Dobrota
Keyword(s):  
Diesel Engines ◽  
Cylinder Liner ◽  
Slow Speed ◽  
Structural Modifications ◽  
Engine Efficiency ◽  
Maritime Shipping ◽  
Tribological System ◽  
Marine Propulsion ◽  
Marine Diesel ◽  
Engine Components

Increasing the energy efficiency of the marine propulsion systems currently represents one of the priorities that have been placed in front of all subjects of maritime shipping market. More and more ship owners aspired to larger and more powerful diesel engines demanded from the marine engine manufacturers to implement various technological modifications to increase the engine efficiency, extend the life of engine components, and thus prolonge regular overhauling period of them. One of the way to meet these demands, among other things, is to improve the tribological characteristics of engine components. The aim of this paper is to present structural modification of tribological system “cylinder liner - piston ring - piston” of large bore slow speed marine diesel engine to reduce friction problems in mentioned system.

scholarly journals Oil Film Formation between Piston Rings and Cylinder Liner of Slow-Speed Marine Diesel Engines

1994 ◽  
Vol 29 (3) ◽  
pp. 261-267
Author(s):  
Keijiro Tayama ◽  
Kazuhiko Maekawa ◽  
Keizo Gotoh ◽  
Noriyasu Inenaga
Keyword(s):  
Diesel Engines ◽  
Film Formation ◽  
Cylinder Liner ◽  
Slow Speed ◽  
Piston Rings ◽  
Oil Film ◽  
Marine Diesel

Paper 4: Epicyclic Gears for Medium-Speed Diesel Engines

1969 ◽  
Vol 184 (15) ◽  
pp. 30-40
Author(s):  
W. M. Brown
Keyword(s):  
Optimum Design ◽  
Diesel Engines ◽  
Design Solution ◽  
Paper Briefly ◽  
Slow Speed ◽  
Epicyclic Gear ◽  
Marine Propulsion ◽  
Medium Speed ◽  
Recent Emergence ◽  
Machinery Design

The recent emergence of high-powered medium-speed diesel engines has provided marine gear engineers with an incentive to develop products such that marine propulsion installations can be evolved which will provide a radical alternative to the direct driven, slow-speed diesel engines which currently dominate the largest sector of the market for power at sea. This paper briefly reviews the changes in ship and machinery design and application which have dictated the need for optimum propulsion units and describes the resulting requirements that are imposed upon the gear units. These requirements are discussed in relation to a range of epicyclic gear units which appear to represent an optimum design solution for a particular sector of the market for power at sea.

scholarly journals Contributions to the study of service characteristics of marine fuels

2018 ◽  
Vol XIX (1) ◽  
pp. 502-508
Author(s):  
Ali L
Keyword(s):  
Fuel Consumption ◽  
International Organizations ◽  
Diesel Engines ◽  
Fuel Injection ◽  
Cylinder Liner ◽  
Operating Mode ◽  
Service Characteristics ◽  
Marine Engines ◽  
Marine Diesel ◽  
A Priority

Since the beginning, development of marine diesel engines was turned towards obtaining a low fuel consumption and the result has reflected in engines construction: increased bore and cylinder liner diameter, higher working pressures and lower piston speeds. Similar improvements have taken place in the supercharging system, innovative fuel injection technologies and changes in combustion pressures. Nowadays, the trend of development has changed, the concept of reducing NOx and SOx emissions became a priority in order to meet the limits imposed by international organizations. As a consequence, a series of changes in operating mode of marine engines was noticed but also several innovations appeared in the construction and development of marine engines.

scholarly journals Methods for determining mechanical losses of marine diesel engines

2018 ◽  
Vol 214 (3) ◽  
pp. 25-38
Author(s):  
Leszek Wontka
Keyword(s):  
Diesel Engines ◽  
Critical Evaluation ◽  
Propulsion System ◽  
Piston Engine ◽  
Advantages And Disadvantages ◽  
Marine Propulsion ◽  
Marine Diesel ◽  
Marine Propulsion System

Abstract The paper presents based on literature critical evaluation of commonly known methods for determining the mechanical losses of a piston engine. Their advantages and disadvantages were pointed out also the possibility of their use in a marine propulsion system was assessed.

scholarly journals Tribology in Marine Diesel Engines

2021 ◽  
Author(s):  
Sung-Ho Hong
Keyword(s):  
Diesel Engines ◽  
Fuel Injection ◽  
Combustion Process ◽  
Tribological Performance ◽  
Engine Room ◽  
Medium Speed ◽  
Marine Engines ◽  
Marine Diesel ◽  
Power Outputs ◽  
Engine Components

This chapter deals with the tribology of marine diesel engines. Several types of diesel engines have been installed and used in the engine room of marine ships. Some of them, used for propulsion, operate at low-speed in a two-stroke combustion process in conjunction with propellers. Four-stroke engines are used for power generation and operates at medium-speed. In general, two or more four-stroke engines, including spares, are installed in the large ships. Tribological problems are important issue in the respect of reliability in the marine diesel engines, and there are many tribological engine components including bearings, pistons, fuel injection pumps and rollers. Moreover, the marine engines have lubricant problems such as lacquering. Improvements to the tribological performance of marine engine components, and lubricants can provide reduced oil and fuel consumption, improved durability, increased engines power outputs and maintenance. Therefore, this chapter shows better designs and methods in order to improve the tribological problem in the marine diesel engines.

OPERATIONAL EVALUATION OF PISTON-RINGS-CYLINDER LINER ASSEMBLY WEAR IN HIGH POWER MARINE DIESEL ENGINES

Tribologia ◽  
2018 ◽  
Vol 271 (1) ◽  
pp. 5-15
Author(s):  
Adam ADAMKIEWICZ ◽  
Jan DRZEWIENIECKI
Keyword(s):  
High Power ◽  
Diesel Engines ◽  
Piston Ring ◽  
Cylinder Liner ◽  
Technical Condition ◽  
Piston Rings ◽  
Protective Layers ◽  
Marine Diesel ◽  
Source Of Information ◽  
Operational Methods

This paper presents an operational evaluation of piston-piston rings-cylinder liner (PRC) assembly wear in marine diesel engines of high power. It is based on visual inspection through cylinder liner scavenge ports. Clearance measurements of piston rings in piston grooves and piston ring gap measurements were used to evaluate the extent of wear of the PRC assembly. Moreover, it is shown that piston ring gap measurements can be used as a reference parameter in wear trend analysis to predict the length of time periods between overhauls (TBO). Furthermore, it has been shown that controlling the wear of chromium (protective) layers of piston ring working surfaces by measuring their thickness with induction and eddy current methods is highly useful. They were accepted as a source of information on PRC lubrication correctness and as a symptom of its technical condition. Factors indicating the necessity of an overhaul and introducing operational methods of improving working conditions between the tribological pair – liner and piston rings have been determined.

Optimization of cylinder liner macro-scale surface texturing in marine diesel engines based on teaching–learning-based optimization algorithm

2020 ◽  
pp. 135065012091156
Author(s):  
Salaheldin A Mohamad ◽  
Mohamed A Kamel
Keyword(s):  
Friction Force ◽  
Optimization Algorithm ◽  
Diesel Engines ◽  
Surface Texturing ◽  
Cylinder Liner ◽  
Oil Film ◽  
Macro Scale ◽  
Marine Diesel ◽  
Teaching Learning Based Optimization ◽  
Teaching Learning

This paper investigates the effect of optimum macro-scale cylinder liners oil groove on the tribological behavior of large bore marine diesel engines. Parabolic bottom shape grooves are selected as the cylinder liner surface texturing. The grooves have been distributed along the stroke in the form of array of circumferential cells with the axial groove centered in each cell. Teaching–learning-based optimization algorithm is applied to get the optimum dimensions of oil grooves, where the objective is to minimize the cyclic average total friction force between the top compression piston ring and the cylinder liner. Numerical simulation based on Reynolds equation is presented to study the effect of optimum grooves’ dimensions on tribological parameters such as hydrodynamic friction, asperity contact pressure, and hydrodynamic oil film pressure. Results showed that the optimum dimensions oil grooves have a significant effect on the total friction force and the cavitation pressure of the oil film.

Improving Tribological Behavior of 2-Stroke Marine Diesel Engine Piston Ring by Cylinder Liner Surface Texturing

2014 ◽  
Vol 620 ◽  
pp. 278-284 ◽  
Author(s):  
Salaheldin A. Mohamad ◽  
Qun Zheng ◽  
Xi Qun Lu
Keyword(s):  
Diesel Engines ◽  
High Speed ◽  
Piston Ring ◽  
Surface Texturing ◽  
Cylinder Liner ◽  
Hydrodynamic Effect ◽  
Micro Scale ◽  
Macro Scale ◽  
Marine Diesel ◽  
Piston Ring Lubrication

Piston ring lubrication in some types of low-speed 2-stroke marine diesel engines is completely different from those in medium-or high-speed diesel engines since the inner surface of cylinder liners are textured with circular grooves in macro-scale and honing texture in micro-scale. In this paper, a numerical model has been developed to study the potential of use of cylinder bore surface texturing, in the form of circumferential oil grooves with different dimensions and densities, and their efficiency to improve the tribological properties of piston ring-cylinder liner tribo-system. The average Reynolds equation has been employed in the area of micro-scale texture and the effect of macro-scale grooves has been incorporated to improve the currently lubrication model. The results showed that the cylinder liner oil grooves can efficiently be used to maintain hydrodynamic effect. It is also shown that optimum surface texturing may substantially reduce the friction losses between piston ring and cylinder liner.

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