The UE engine is the only Japanese-developed low speed diesel engine since 1955. In this paper, the latest developments and technologies of UE engines are explained. The engine program, the latest LSE series in particular, is introduced first, followed by a discussion on the UEC Eco-Engine, an electronically controlled engine, which entered service in June 2005. This engine has excellent service results without any emergency vessel stop even up to the present. Finally, focus is given on the ECL system, an electronically controlled cylinder lubricating system which quite effectively reduces cylinder oil consumption, and which has also received good service results.
Light Cycle Oil (LCO), a highly aromatic distillate which is a by-product of from the FCC process in oil refining, can be suggested as a possible low sulfur fuel for marine engines in the near future. Therefore experimental investigation of the influence of LCO on the overall combustion characteristics is necessary in order to elaborate the feasibility of LCO as a low sulfur fuel.Experiments have been carried out on a four-cylinder high speed diesel engine. LCO has been blended with gas oil (GO) at varying percentages of 40% to 80%. A highly accurate PM measurement has been achieved using a dilution tunnel.
Marine air pollutants, NOx and SOx, have an adverse influence on the environment. In the 26th MEPC (Marine Environmental Protection Committee) of IMO (International Maritime Organization) held in 1988, a proposal on the prevention of air pollution from ships titled "Exhaust Gas Emission from International Marine Transport" was made by Norway. As a result of deliberate discussions, emissions control (Phase 1) of exhausted NOx values came into force on May 2005. Stricter regulations (Phase 2 & 3) will be implemented in the near future. These stricter regulations will increase the ECA (Emission Control Area). Therefore, the authors propose an estimate of marine exhaust gas dispersion on Osaka bay.The simulation presented in this paper uses the Pasquill-Gifford model to simulate marine exhaust gas dispersion. The purpose of this simulation is to show the influence of marine exhaust gases at the coastal areas. The diffusion model at the sea surface adopts the OCD (Off-shore and Coastal Dispersion) model which utilizes the Monin-Obukhov atmospheric stability parameter. For this study, 40 vessels of over 500 gross tonnage were chosen using an AIS (Automatic Identification System). The degree of incidence in the coastal areas from marine exhaust gases was estimated to be about 50 % for NOx and 30 % for SOx.
The authors investigated the relation between the deterioration of SCR catalyst and the exhaust gas conditions in order to apply the SCR NOx removal system to marine diesel engines. The performance of the deteriorated catalyst was recovered by a six-hour exposure with NOx removal reaction of simulated exhaust gas at a sufficiently high temperature depending on the SO2 concentration of the gas. One hundred-hour exposure tests were conducted on the brand-new catalyst with NOx removal reaction of simulated exhaust gas at the temperature at which the deteriorated catalyst was recovered by a six-hour exposure. No deterioration occurred.
Regulation of NOx emissions from marine diesel engines (DE) by the International Maritime Organization (IMO) has been carried out globally since May 2005. In the near future, particulate matter (PM) will be regulated as well. In Tokyo, Japan, the control of emissions from coastal vessels in the harbor is being pushed forward. In addition, demand for diesel particulate filters (DPF) from shipping and ship management companies operating pure car carriers (PCC) and container ships is anticipated. The use of DPF prevents the pollution of cargo by the exhaust from DE generators while the ships are moored in harbor. Since 2007, Mitsui Engineering & Shipbuilding Co., Ltd. and Daihatsu Diesel Mfg. Co., Ltd. have been developing a DPF applying non-thermal plasma technology for an onboard 1MW generator using fuel oil with 2,000 ppm sulfur to address customers' needs. As a result, 50% and 70% soot reduction have been achieved for single and serial connection of DPF respectively under steady state conditions in bench tests of a pilot model. A performance test of the DPF for a 1MW scale DE has also been carried out. The details of the test work, the system automation, and the modifications for onboard deployment are described in this paper.
Boiler exhaust gas consists of many components that cause air pollution, such as: particulate matter (PM), SOx, NOx, COx, etc. These pollutants normally are mixed. To eliminate them, a scrubber is currently used, depending on a coal fuel used for combustion source in the boiler. For PM, new guidelines will be changed from the existing PM10 to PM2.5 within the next few years; The scrubber is widely used for the collection of PM from industrial exhausts because of its low equipment and maintenance costs combined with operational safety and high collection efficiency. The electrostatic water spraying scrubber, studied in this paper, is one of such types of devices, which combines advantages of electrostatic precipitators and inertial wet scrubbers, and removes many shortcomings inherent to both of these systems operating independently. Unlike wet electrostatic precipitators in which PMs are precipitated only on the collection electrode, in electrostatic water spraying scrubber, the collection of PMs takes place in the entire the scrubber. Compared to inertial scrubbers, the electrostatic water spraying scrubbers can operate at lower droplet velocities, but total collection efficiency is over 93% of all PM sizes
The electronically controlled fuel injection system (EFI) has been originally developed to improve the spray combustion at low load, where the fuel injection pressure is reduced compared to that of the design point at full load, emitting more smoke and particulate matter (PM). In this paper, various possibilities for the application of EFI in marine engines are introduced, with regards to NOx reduction and improvement of low-grade fuel combustion. The effects on spray combustion are demonstrated using a specially designed visualization test engine.
Developments of new systems for stable combustion of liquid coal fuel have been the subject of scientific researches for many years. Stable combustion of coal oil has the advantages of good flame stability, low exhaust gas emission, and low cost. Coal oil combustion without any treatment is believed to cause damage to the environment. Research on adding water into coal fuel as emulsified fuel is considered as one alternative to overcome environmental problems. In this paper, the effect of emulsified coal fuel with 10% v/v of water on the formation of exhaust gas was investigated. Experimental results showed a more stable combustion and a decrease in NOx and other components in the exhaust gas. Keywords: air pollution, exhaust gas, NOx, CO, CO2, coal fuel, coal emulsified fuel
Recently, alternative fuels are actively studied all over the world. The main reasons are the depletion of crude oil, soaring oil prices and the global warming problem. Biomass fuel is one of the most up and coming alternative fuels from the viewpoint of carbon neutrality. The problem with biomass fuel is that it creates competition between food and fuel. Thus, the authors considered Jatropha which is a non-food plant. Its seed contains phorbol ester which is toxic and thus is inedible. The combustion analysis of Jatropha oil mixed with Marine diesel oil was studied. A 4-stroke pre-combustion chamber type compression ignition engine was used because of its ability to handle inferior fuels. Increasing the mixture ratio of Jatropha oil resulted in reduced NOx emissions and a decreasing tendency of smoke opacity. Each fuel showed an approximately equal value of thermal efficiency. The results show that in a pre-combustion chamber type compression ignition engine, Jatropha oil and blended fuel can be used as an alternative fuel to MDO.
Statistical analyses of ROHR (rate of heat release) curves from a modified FIA (Fuel Ignitability Analyser) were introduced for the first time to distinguish trouble-inducing bunker fuel oils (TIO) from trouble-free fuel oils (TFO). The modified FIA employed longer injection duration, higher spray quality, and higher air temperature, which made its combustion conditions closer to those in an actual marine diesel engine. In this study, Linear Discriminant Analysis (LDA) and the Mahalanobis Taguchi System (MTS) were applied to extract effective variables from ROHR curves. Very promising results were obtained, and thus a reliable method for the distinction of bunker fuel oils was realized.
To realize the Half Fuel-Oil Consumption Vessel under the same conditions of cruising speed and deadweight, it is necessary to choose and integrate drastic and significant energy saving techniques. These are reducing hull frictional resistance on the vessel's flat bottom by air bubbles lubrication, enhancing propulsive efficiency by twin large diameter propellers with twin-skeg hull form, recovery of rotational energy in the propeller slipstream by fins, recovery of the waste heat from the main engine with binary thermal energy conversion system, and utilization of wind energy in the sea with high performance hard wing sail. It is suggested that the integration of the above-mentioned techniques makes the Half FOC Vessel possible in the near future.
To investigate the effects of ship motion on circulating fluidized beds (CFBs), three-dimensional numerical simulations of dense gas-solid flows have been carried out with a two-fluid model and its sub-models based on the kinetic theory of granular flows. In comparison with an upright CFB, a large number of solid particles accumulate in the lower part of the riser under the rolling and constantly inclined conditions, so that solid circulation flux Gs is reduced by more than approximately 70 % under the present set of computational conditions. To determine the reason for the reduction of Gs, downward solid flux and the force of drag and gravity acting on the solid phase were evaluated in the riser of a constantly inclined CFB. Examination of the above quantities showed that in addition to the action of the gravity component perpendicular to the riser axis, the magnitude relation of the axial component of the drag and gravity forces mainly caused the reduction of the solid circulation flux in the present CFB under the inclined condition.
The paper consists of three main objectives: the mathematical model of diesel engine propulsion powerplant, hull-propeller interaction model including the effect of propeller emergence (propeller racing) and real-time dynamic behavior of the ship propulsion plant. One of the main advantages of the model is that it enables to investigate the dynamic behavior of diesel engine and speed control system at off-design and transient condition, allowing for real-time assessment of severity of propeller load demand fluctuation in order to improve model-based speed control schemes to ensure the safe operation of ship propulsion plant.
In recent years, the quality of marine residual fuel oil has been deteriorating due to the escalating prices of crude oil and the sophistication of oil refining technologies. In this regard, the deterioration of combustibility causes problems such as poor combustion in diesel engines, which can result in major failures. In the present paper, we summarize the characteristics and trends regarding the ignitability and combustibility of marine residual fuel oil, as well as the analysis results of their relation to case studies of combustion troubles encountered.Furthermore, upon applying the Mahalanobis-Taguchi system to the establishment of a practical method for evaluating the quality of marine residual fuel oil, it was found that trouble inducible oil can be easily identified, indicating that it is an effective analytical method.
Contamination of marine fuel oil with fluid catalyst cracking (FCC) particles, which are used as catalysts in refining crude oil, is a major source of engine problems. FCC particles have high hardness and can enter the space between the plunger and barrel of the fuel oil pump as well as that between the cylinder liner and piston ring, resulting in abrasive wear of these parts. Therefore, the particles are removed by a fuel oil treatment system onboard the vessel in an effort to prevent engine problems. However, FCC particles in marine fuel oil remain a major problem.Methods of testing the separator performance for a specific test oil were established in JIS F6601-1996 and in the European Committee for Standardization (CEN)’s Agreement CWA15375. Moreover, separator manufacturers report separation efficiencies of 80-90% for FCC particles using these test methods. However, the results do not reflect the separation efficiency of the fuel oil treatment system onboard an actual vessel. Therefore, we evaluated the separation efficiency of fuel oil treatment systems for FCC particles onboard actual vessels with an inductively coupled plasma metal analyzer and particle counter.
It is very important to evaluate the strength of marine hooks in order to prevent accidents. Thus, the authors studied the strength of marine crane hooks, which are widely used for marine cargo handling, by static-load and fatigue experiments. From the results of static load and cyclic load tests, it was confirmed that the strength of the crane hook was more sensitive to diameter change than the rounding, and its fatigue life was also more sensitive to a diameter change than a rounding change.
Forced convection transient heat transfer coefficients due to exponentially increasing heat input were measured for helium gas and carbon dioxide gas flowing over a partially twisted heater. A partially twisted platinum plate with a thickness of 0.1 mm was heated by electric current and used as the test heater. The gas flow velocities ranged from 1 to 10 m/s, the gas temperatures ranged from 313 K to 353 K, and the periods of heat generation rate ranged from 46 ms to 17 s. The study showed a strong enhancement in the heat transfer coefficient for the twisted heater over that of a plate heater. Compared with those of a plate heater, the heat transfer coefficients of helium gas and carbon dioxide gas were enhanced 13 % and 28 %, respectively. Correlations for quasi-steady state heat transfer of the twisted heater in helium gas and carbon dioxide gas were obtained based on the experimental data.
The pool boiling CHFs were investigated to clarify the generalized phenomena of transition to film boiling at transient condition. The CHFs were measured on a 1.0 mm diameter platinum horizontal cylinder for exponential heat generation rates with various periods for saturated liquids at atmospheric pressure. The incipience of boiling processes was completely different depending on pre-pressurization. Also, the dependence on pre-pressurization in transient CHFs changed due to the wettability of boiling liquids. The trend of typical CHFs were clearly divided into the first, second, and third groups for long, short, and intermediate periods, respectively. Due to the effect of pre-pressurization, the boiling incipience mechanism was replaced from that by active cavities entraining vapor to that by the HSN in originally flooded cavities.
In material processing applications related to shipbuilding products, heat transfer involving a combined form of Couette and Poiseuille flows can be encountered as the axially moving cylindrical rod continuously exchanges heat with the surrounding environment. The authors examined how the moving cylinder velocity affects heat transfer while considering viscous dissipation as it is caused by the shearing of fluid layers. In this analytical study, a fully developed Couette-Poiseuille flow was investigated in the case of a constant wall flux for both cooling and heating processes. The solutions are given for different radius ratios and show the effects of the relative velocity and Brinkman number on the temperature distributions and Nusselt number at the inner cylinder wall. It was observed that the bulk temperature changes sharply when the directions of the flow and the core are opposite.
In recent years, the PC based engine room simulator (ERS) has been introduced maritime education and training, and useful for the acquisition of the operational knowledge of the marine engine plant. However, the some part of operational knowledge acquired as a long-term memory might be lost with the passing of time. Therefore this report deals with the influence of students' behavior of performance in ERS. As progressing study, the performance data of the marine engine plant was collected two times. The first data was collected in February of the first grader, and the second data of the same students was collected in a simultaneous period of the second grader after one year. According to the result of the analysis, it became clear that the performance time increased and the operation errors did not increase with the passing of time. Therefore, it is supposed that there is little disappearance of operational knowledge of ERS, and the continuity of education effects of ERS is identified.
Generally, in-depth knowledge is required of all huge plant operators in order to continuously keep the plant in a good condition. Ship engineers have the same work as huge plant operators except for the conditions of self-reliance and self-sufficiency at sea. On the basis of the cognitive process of human activities, Rasmussen proposed three different modes, such as the knowledge-based mode, the rule-based mode, and the skill-based mode. An important but complex feature is to understand how to accomplish the plant operator shift between each mode. In this paper, the authors focus on improving the proficiency of ship engineers. Some experiments were carried out on the training ship of the National Institute for Sea Training, Japan.