Low-speed Marine Diesel Engine Research Articles

The Application of Analytic Hierarchy Process in the Evaluation of Simulation Models of Marine Diesel Engine

Facing to the problem of hierarchical structure decision analysis which is made of scheme level + factor level + target level, the analytic hierarchy process gives a whole set of solution and process. This method is used to evaluate diesel engine simulation model. Evaluate original mean value model of large-scale low-speed marine diesel engine and the new one by this method. Calculated results prove this method is applicable.

Modeling and Simulation of a Certain Warship Diesel Engine Based on AMESim

As the power source of warship, diesel engine determines the dynamic performance of the whole warship. In this paper, a simulation model of MAN B&W7S80MC low-speed two-stroke marine diesel engine, used by certain warship, is developed. Simulation analysis is carried out based on LMS Imagine.Lab AMESim. The simulation results show that the model has good accuracy and dynamic characteristics, thus the model can simulate for control design, performance analysis and simulation of the power source of warship.

SIMULATION OF THE COMBUSTION PROCESS IN THE ELECTRONICALLY CONTROLLED MARINE DIESEL ENGINE

The introduction of the electronically controlled low-speed diesel engines has raised a number of new problems caused mainly by the influence of these electronic system settings on the combustion process. The wide set of the combustion press settings is now available for the chief engineers on the board of the ship and for the shipyard experts during the sea trials. This opens many new possibilities for the combustion process optimization but also causes the danger of the serious engine malfunction due to the improper settings. The paper presents the mathematical model of the electronically controlled low-speed marine diesel engine ant the special attention is paid to the available settings of the combustion process. The effective compression ratio, the injection timing and the exhaust valve setting can be adjusted in a similar manner like in the actual engine. The combustion pressure curves, the mean indicated pressure, the exhaust gas temperature can be observed when changing the combustion settings. The paper describes in detail the results of the several most typical simulations like change of the given combustion pressure increase, the change of the effective compression ratio, the change of the exhaust valve opening timing and the change of the maximum load setting.

Research on the Semi-Physical Simulation Technology of High Pressure Common Rail Electronic Control System for Low-Speed Marine Diesel Engine

In this paper, the semi-physical simulation technology is introduced with the design and implementation of a semi-physical simulation test bench. A certain low-speed marine diesel engine of high pressure common rail (HPCR) electronic control system is taken as the subject of the test bench. In order to retain the functional and structural features of the HPCR electronic control system, the essential components are in consistent with the target engine, and some auxiliary parts are simplified and reformed. Specially, a real-time simulation model is built based on the principles of Mean Value Engine Model and cylinder moving method, which captures the requirements of ECU, such as the crank angle, the exhaust valve stroke signal, the scavenging pressure and so on. Therefore a closed-loop control system is accomplished including a real-time controller deployed in the simulation model, ECU and the executing agency of HPCR system. Additionally a monitoring management system is developed for the test bench with the functions of acquiring signals, monitoring parameters, storing data, alarming and etc. Finally, some tests are finished in the test bench and through analyzing the experimental results, the test bench can perform the characteristics and functions of the HPCR electronic control system. The semi-physical simulation technology can be used for the functional verification and performance test of HPCR electronic control system for the low-speed marine diesel engine.

Modeling the Distribution of Sulfur Compounds in a Large Two Stroke Diesel Engine

In many years large low speed marine diesel engines have consumed heavy fuel oils with sulfur contents in the order of 2.5–4.5 wt %. Present legislation requires that the fuel sulfur is reduced, and in the near future the limit will be 0.5 wt % globally. During combustion most of the sulfur is oxidized to SO2 from which a fraction is further oxidized to SO3. SO3 may combine with H2O and condense as liquid sulfuric acid that promotes corrosive wear on e.g. cylinder liners. To extend engine lifetime and reduce costs for lubrication it is pivotal to identify formation of SO3 with respect to operational conditions and sulfur feed. This work presents a computational model of a large low speed two-stroke diesel engine where a 0D multizone approach including a detailed reaction mechanism is employed in order to investigate in cylinder formation of gaseous SO3 where fuel burn rates are based on experimental pressure traces. In contrast to NO the SO3 does not really form at the highest combustion temperatures, but like NO the formation of SO3 is very sensitive to the rate that fresh air mixes with hot combustion products. Consequently a simple mixing rate is proposed and calibrated in order to meet experimental results of NO. For a large low speed diesel engine the model shows that 3–5% of the injected sulfur is oxidized to SO3 that is formed primarily in the temperature range from 2000 to 1300 K during cylinder expansion. In addition the model is used to reduce the full reaction mechanism from 96 to 7 elementary sulfur reactions without compromising the SO3 to SO2 ratio.

Study on Air Intake and Cooling System for Marine Diesel Engine

Regarding the power, the efficiency and the discharge questions of the low-speed diesel engine, this article studied emphatically the Miller cycle, the analysis technology for the air intake system, and the matching technology for the intake and the exhaust. On the foundation of the twin inlet structure the paper analyzed the intake swirl control area and its influence to the gas charging efficiency, proposed the design scheme for the invariable intake swirl control system. By matching reasonably the intake, the exhaust, and the injection process of the diesel engine, the combustion process is further optimized to satisfy the target request for the complete machine’s power, fuel oil efficiency and emission. Aiming at the high-power low-speed marine diesel engine, the paper analyzes the impact of the diesel engine’s cooling to the power, economy and NOx’s emission, studies the variable flow control method and system of the diesel engine cooling water and proposes the scheme setting up the intercooler system and the body cooling system independently in the diesel engine. The results show that the methods and systems are better to improve the engine power, reduce the fuel consumption and NOx’s emission. DOI : http://dx.doi.org/10.11591/telkomnika.v12i2.4213

舶用低速ディーゼルエンジンの溶接製造技術

舶用低速ディーゼルエンジンの溶接製造技術

Full Shafting-Based Elastohydrodynamic Lubrication Simulation for Main Bearings of Marine Diesel Engine

To predict and analyze accurately the lubrication characteristics and its influencing factors of main bearing for large low-speed two-stroke marine diesel engine, based on EHD lubrication model of dynamically loaded bearing, coupling simulation between EHD and MBD for main bearing of marine diesel engine was carried out. Systemic models were established separately considering the independent crankshaft of diesel engine and the full shafting of propulsion power plant. Main bearing load, peak oil film pressure, oil film pressure distribution, MOFT and orbital path in one working cycle under rated working conditions were investigated, and simulation results were compared based on both models. The results show that, if the impact of full shafting was considered, the lubrication characteristics of No.8 main bearing changed significantly, the lubrication characteristics of other main bearings were similar as the simulation results of the independent crankshaft model.

Elastohydrodynamic Lubrication Analysis of Marine Sterntube Bearing Based on Multi-body Dynamics

To predict and analyze accurately the lubrication characteristics and its influencing factors of marine sterntube bearings, coupling simulation between EHD and MBD for sterntube bearings of marine diesel engine propulsion system was carried out. FE models for crankshaft and main bearings of a two-stroke low-speed marine diesel engine, intermediate shaft, tailshaft, intermediate bearings and sterntube bearings of a chemical carrier were established, and the results files generated from reduced FE models by employing substructure methods were entered into MBD model. Sterntube bearing forces, load distribution, orbital path, minimum oil film thickness(MOFT) and total friction power loss on fore sterntube bearing and aft sterntube bearing in one working cycle under rated working conditions were investigated. Simulation results show that the sterntube bearings were safe enough for normal operation, the vertical load and the total friction power loss on aft sterntube bearing were significantly higher than that of fore sterntube bearing.

Research on Emission Control of Marine Diesel Engine

In response to the increasingly stringent diesel emission regulations, the paper analyzes the relationship of the low-speed marine diesel engine's emission with the combustion process, the fuel injection law, the exhaust recirculation and the SCR. Then the scheme of the fuel injection system with the high-pressure common rail for the low-speed diesel engine is proposed, and the test system for the diesel engine's emission performance is established. Through the experimental research, the optimization and matching technology for the diesel combustion process based on the emission control is analyzed, and the best injection law of the diesel engine is revealed under the different conditions. That will provide the technical support for the design and operating management of the diesel engine.

Analysis for Combustion Process in Cylinder of 5S60 Diesel Engine

The optimization and matching question for the low-speed diesel engine’s combustion process determines its power, efficiency and emission. But the optimization and matching of the combustion process is related with the fuel injection rule, the intake swirl control, the valve timing adjustment, the combustion chamber structure, the operating condition parameter and so on. This paper takes the 5S60 marine low-speed diesel engine as the study object. The whole running phase oriented model based on the unified multi-domain has established, and the analysis for the diesel engine’s combustion process in cylinder has carried on. The analysis result provides the technical support for the economical, safe and reliable operation of the diesel engine. Thus the combustion process in cylinder is improved, the diesel engine’s performance is enhanced, and the pollutant discharge is reduced.

Study on the Assembly and Adjustment Technology of the Low-Speed Marine Diesel Engine

This paper takes the high-power low-speed marine diesel engine as an object to carry out a series of technical researches. These technologies include the assembly and the precision adjustment on the components of the piston, the crosshead and the connecting rod, and the assembly and the timing adjustment on the fuel and exhaust system, the assembly and the precision adjustment on the crankshaft and the engine base. The test technology and system of the high-power marine diesel engine are studied. The new method to determine the assembly quality of the piston and crosshead based on the strain measurement for the small end of the connecting rod and the oil film thickness measurement for the crosshead and the supporting plate is proposed. The stress measuring system for the engine body is built. The engine body’s deformation before and after the crankshaft assembly and the bearing block’s deformation during the crankshaft movement are analyzed to evaluate the stress situation of the crankshaft after the installation. Therefore the assembly technology for the low-speed high-power diesel engine is improved to ensure the reliability of the diesel engine work.

Finite Element Analysis of Marine Diesel Engine Frame

Taking the marine low-speed high power diesel engine frame for example, created a three-dimension model through UG. By using the finite element software ANSYS investigated the body’s stress status and displacement which provides a valuable reference for the structural optimization of the cylinder block of diesel engine’s design.

Study on Matching and Optimization of Low-Speed Diesel Engine’s Cooling System

Aiming at the high-power low-speed marine diesel engine, the paper analyzes the impact of the diesel engine’s cooling to the power, economy and NOx’s emission, studies the variable flow control method and system of the diesel engine cooling water and proposes the scheme setting up the intercooler system and the body cooling system independently in the diesel engine. The results show that the methods and systems are better to improve the engine power, reduce the fuel consumption and NOx’s emission.

Validation of a zero-dimensional model for prediction of NOx and engine performance for electronically controlled marine two-stroke diesel engines

The aim of this paper is to derive a methodology suitable for energy system analysis for predicting the performance and NOx emissions of marine low speed diesel engines. The paper describes a zero-dimensional model, evaluating the engine performance by means of an energy balance and a two zone combustion model using ideal gas law equations over a complete crank cycle. The combustion process is divided into intervals, and the product composition and flame temperature are calculated in each interval. The NOx emissions are predicted using the extended Zeldovich mechanism. The model is validated using experimental data from two MAN BW one case being data subject to engine parameter changes corresponding to simulating an electronically controlled engine; the second case providing data covering almost all model input and output parameters. The first case of validation suggests that the model can predict specific fuel oil consumption and NOx emissions within the 95% confidence intervals given by the experimental measurements. The second validation confirms the capability of the model to match measured engine output parameters based on measured engine input parameters with a maximum 5% deviation.

舶用低速（UE型）機関におけるIMO規制対応の現状及び将来技術

舶用低速（UE型）機関におけるIMO規制対応の現状及び将来技術

Inertia friction welding process analysis and mechanical properties evaluation of large rotor shaft in marine turbo charger

The two aims of this study are first, determining the optimal welding process parameters by using the finite element simulation and second, determining the optimal tempering temperature by evaluating the mechanical properties of friction welded part for manufacturing large rotor shaft. Inertia welding was conducted in order to make the large rotor shaft of turbo charger for low speed marine diesel engine. The rotor shaft is composed of the 310mm diameter disk and the 140mm diameter shaft. Since diameters of disk and shaft are very different, the integration using friction welding reduces manufacturing cost compared with the forming process of which a disk and shaft are forged into one body. Finite element simulation was performed, because inertial welding friction process depended on many process parameters, including axial force, initial revolution speed and energy, amount of upset, and working time. It is expected that this modeling will significantly reduce the number of experimental trials needed when determining the optimal welding parameters. Inertia welding was carried out with optimal process parameter conditions obtained from the simulation results. Welded joint part, made by friction welding, had very poor mechanical properties, and so it required heat treatment. The base material used in the investigation was SFCMV1 (SANYO special steel, high strength low alloy Cr-Mo steel) of 140mm diameter. In the study, heat treatment test carried out quenching (950 °C, 4hr, oil cooling) and tempering (690–720 °C, 6hr, air cooling) for friction welding specimens. The various tests, including microstructure observation, tensile, hardness, and fatigue tests, were conducted to evaluate the mechanical properties under various heat treatment conditions after inertia welding.

舶用大型ディーゼル機関の環境保全の現状と課題

舶用大型ディーゼル機関の環境保全の現状と課題

On the possible increasing of efficiency of ship power plant with the system combined of marine diesel engine, gas turbine and steam turbine in case of main engine cooperation with the gas turbine fed in parallel and the steam turbine

The article presents a concept of a combined large-power ship propulsion system, composed of the leading internal combustion main engine associated with a power gas turbine and the steam turbine system, both utilising the energy taken from the main engine exhaust gas. In the examined variant the power turbine, arranged in parallel with a turbocharger, is fed with the exhaust gas from the exhaust manifold. A calculation algorithm is presented, along with sample calculations for particular subsystems: supercharging, gas power turbine, and steam turbine system. Assumptions were formulated for the calculations, and were complemented by the adopted limits. Selected system parameters were confronted with the experimental investigations available in the literature. The performed power optimisation of the entire combined marine power plant took only into account the thermodynamic point of view, leaving aside technical and economic aspects. The numerical calculations were performed for the 52 MW low-speed marine diesel engine.

21507 環境規制対応技術の開発動向(船舶の環境関連技術の新しい展開(2),OS.14 船舶の環境関連技術の新しい展開,学術講演)

The regulations to prevent air pollution from ships are supposed to be further tightened up. As for the IMO NOx regulation on low speed marine diesel engines, allowable NOx emission limit will be possibly tightened by over 80% from the present regulation in 2015 or 2016. On "Mitsubishi UE-Engine", several candidate technologies are under development. This paper introduces three technologies amongthem. First one is "Fuel Injection Rate Control" which has proven the reduction of NOx without SFOC penalty on "UEC Eco-Engine". The next one is "Water-Injection" such as stratified fuel water injection or independent water injection system. Those can reduce NOx corresponding to the amount of water. The third one is "Selective Catalytic Reduction" which is one of the after-treatment technologies. A new reduction catalyst which can preserve its performance even at low temperature with SOx is under development.