Ship Diesel Engine Research Articles

拡散シミュレーションによるＮＯｘ規制効果の検討

The International Maritime Organization (IMO) is working for the further advancement of regulation in NOx emission reduction for ship's diesel engines. As for Tier III, which is assumed to be entering into force in 2015, two proposals were discussed at the 11th meeting of BLG Subcommittee in February 2008. One was a uniform regulation over the world with 40% to 50% reduction from the Tier I regulations. The other was a geographically controlled regulation with an 80%, or higher, reduction for a designated area. Tier II level for others are applied. In the present study, a simple diffusion model is employed to estimate the NOx concentration over the land area for the case that each regulation is applied. Simulation studies have revealed that an appropriate distance given as the boundary in the geographical regulation could reduce the NOx concentration over a land area, to a comparable level as the uniform regulation can be estimated to achieve.

The results of torsional vibration calculation in the ship diesel engine propulsion system

The traditional procedure of calculating the torsional vibrations in the ship diesel engine propulsion system is shown in this work. A real system is replaced with an equivalent 19-degree of freedom system and its free and forced torsional vibrations as well as appropriate torsional vibration strains have been analyzed. .

The results of torsional vibrations measurement in the system of diesel engine propulsion

The measuring treatment, as well as the results of torsional vibrations in the transfer from the ship diesel engine to the propeller are shown in this work. The measuring principle of torsional stress according to the function of rotation number of ship engine is applied by using of modern measurement equipment. The position of critical rotation numbers and the level of propeller shafts stress have been checked, and on the basis of these indices the evaluation of technical condition of the system has been estimated from the aspect of torsional vibrations strain. .

風力発電システムの大形石炭専用船への応用に関する研究

As for electric power generation on land, the wind energy conversion system is widely used because of its environmental problems. For the marine environment, some methods to reduce air pollution such as CO2, NOx, and SOx from diesel engines of ships have been discussed recently.In this paper, a study on the application of the wind energy conversion for the electric power generation system of a large ship was carried out.At first, the paper considered and proposed the design procedure of the introduction of the wind energy conversion system to ships. Secondly, a case study was carried out on the wind energy generation system to a coal cargo ship using the proposed design. Finally, in order to evaluate the application of the wind energy conversion system, the fuel consumption and NOx and SOx emission were compared with those of the conventional electric power generation system consisting of diesel engine generator. The electric power generation system could reduce the fuel consumption and NOx and SOx emission from the ship. The application of the wind energy conversion system to the electric power generating system of ship is worth discussing to solve the marine environmental problems.

An algorithm for robust noninteracting control of ship propulsion system

In this paper, a new algorithm for noninteracting control system design is proposed and applied to ship propulsion system control. For example, if a ship diesel engine is operated by consolidated control with controllable pitch propeller (CPP), the minimum fuel consumption is achieved satisfying the demanded ship speed. For this, it is necessary that the ship is operated on the ideal operating line which satisfies the minimum fuel consumption, and the both pitch angle of CPP and throttle valve angle are controlled simultaneously. In this context of view, this paper gives a controller design method for a ship propulsion system with CPP based on noninteracting control theory. Where, linear matrix inequality (LMI) approach is introduced for the control system design to satisfy the given H~ constraint in the presence of physical parameter perturbation and disturbance input. To the end, the validity and applicability of this approach are illustrated by the simulation in the all operating ranges.

Optimization Control for Fuel Consumption of a Ship Propulsion System with CPP Using Decoupling and LMI Approach

If a ship diesel engine is operated by consolidated control with Controllable Pitch Propeller (CPP), the minimum fuel consumption is achieved satisfying the demanded ship speed. For this, it is necessary that the ship is operated on the ideal operating line which satisfies the minimum fuel consumption, and the both pitch angle of CPP and throttle valve angle are controlled simultaneously. In this context of view, this paper gives a controller design method for a ship propulsion system with CPP based on decoupling control theory. Where, Linear Matrix Inequality (LMI) approach is introduced for the control system to satisfy the given H∞ constraint in the presence of physical parameter perturbations. To the end, the validity and applicability of this approach are illustrated by simulation in the all o-perating ranges.

歯付ベルトのパラメータ励振

Timing belts are usually used as standard apparatus for power transmission and the timing device in the diesel engines of ships, the OHC engines of cars and the machine tools. In such cases, it is well known that the timing belt is subjected to the fluctuation of tension which is caused by the eccentricity of the pulley shaft, engagement of the belt and the pulley, and the fluctuation of torque given to the pulley shaft. As a basic research on this problem, this paper describes the results of analytical and experimental investigations of the parametric resonance phenomena of the timing belt stretched vertically. As the first step, the author regarded the timing belt as a system with string and applied Mathieu's equation to the behavior of the timing belt which is subjected to periodic tension, and then compared the experimental results with approximate stability chart for Mathieu's equation. As a result, the experimental results agreed almost with approximate stability chart for Mathieu's equation. Namely, the vibration characteristics of timing belt showed remarkable features of the parametric excitations.

A study of the causes of cracks in bed plates of a ship's diesel engines

In cargo vessels, large machines such as engines in which part of the assembly consists of cast-iron structures are often exposed to the risk of crack formation. The present study is concerned with two diesel engines of identical type. A number of fractures were observed in the bed plates. Analysis of the type of loading and crack propagation shows that the fractures could have been predicted.

Adaptive Minimum Energy Control of Large Ship Diesel Engines

The economics of running large ship diesel engines are such that even small savings (on the order of 0.1%) are of great interest to ship owners. The overall efficiency of a given engine is determined mainly by the design of the engine/propellor combination but small reductions in fuel consumption can be obtained through careful design of automatic controllers for the system. Such regulators require accurate models for the internal states and state functions of the engine and in particular for its thermal efficiency. A new nonlinear model for a large ship diesel engine has recently been obtained by one of the authors. This model gives reasonably accurate estimates of the thermal efficiency that may be expected under the most important operating conditions.On this basis an adaptive energy saving controller has been designed and tested. Depending on sea conditions, simulations suggest that savings on the order of those indicated above should be possible. The project is carried out in cooperation with M.A.N.-B & W Diesel A/S, Copenhagen, Denmark.

CPプロペラの運航経験

These days, according to the up-going price of the fuel oil, the selection of the marine engine type seems to be decided only from the view point of the economy. Resultantly the big ships, that used to adopt the steam turbine engine, have been mounting the diesel type engine.No body doubts that the internal combustion engine like the diesel engine furtherly surpasses the external combustion engine on the rate of fuel consumption, however, the diesel engine has some undesirable features as marine engines. One of them is that it is difficult for the engine to keep the output at 85% MCR without suffering from the thermal and/or torque load to the engine when the fluid resistance of the ship submerged hull increased by the foulness due to aging progression or encountering rough sea condition. The another is that it requires us much more maintenance works than the other type of engine.Meanwhile, the type of controllable pitch propeller is considered to save effectively those weak points on the propulsion diesel engine. In order to clarify these points, a comparison between the fixed pitch propeller installed motor ships and the controllable pitch propeller ones is tried to list up on this report, considering from an actual experience on the CPP equipped big ship for 400 days.Also, the affection to the diesel driven propulsion which has been brought about by the aging increase of the hull submerged area fouling as well as rough sea condition, has been measured and described on the ship's diesel engine load diagram for the purpose of easy understanding. And through the actual experience, viewing from the operational stand point the advantage of the cppdiesel equipped ship on several phases is stated on this report.