该论文已在赫尔辛基举行的第28届CIMAC大会上发表，论文的版权归CIMAC所有。Mitsubishi UE engines feature high economic efficiency, high reliability, and environment-friendliness. High economic performance of the UE engine can give solutions to save ship owners operating costs and achieve long-term safe operation. Mitsubishi UE engines have been developed and improved for more than half a century, adapted more strict environmental regulations and market needs. IMO’s NOx Tier III regulation which provides the reduction of the NOx emission by approximately 76% compared to the Tier II regulation within ECA (Emission Control Area) will be applied to ships keel laid on or after 1 January 2016. To comply with IMO Tier III regulation, Mitsubishi Heavy Industries Marine Machinery & Engine Co., Ltd. (MHI-MME) has developed a new exhaust emission reduction technology “Low Pressure Exhaust Gas Recirculation (LP-EGR) system” because of its drastic NOx reduction possibility. The Mitsubishi LP-EGR system is a system which generation of NOx is suppressed by changing combustion condition inside an engine, by means of recirculating a part of low pressure exhaust gas emitted from an engine turbocharger outlet to a turbocharger intake after scrubbed by the EGR scrubber. The system from low pressure side to low pressure side, is so called low pressure system.

该论文已在赫尔辛基举行的第28届CIMAC大会上发表，论文的版权归CIMAC所有。LNG-fuelled engines are the focus of growing interest due to their advantages of lower emissions and operating costs. It is estimated that the number of vessels with LNG-fuelled engines will be around 1,000 in 2020. LNG-fuelled 4-stroke engines have been used for some years in power generation applications worldwide and as marine propulsion engines, primarily in Europe. In contrast, few 2-stroke LNG-fuelled are in service at present. LNG-fuelled 2-stroke engines have been studied since the 1980s. The first such commercial engine was a MitsuiMAN B&W 12K80MC-GI-S engine, which installed at a 40 MW power plant in 1994. Initially, low base number (?10BN) cylinder lubricants were used for the engine. But liner scuffing and severe wear of liners and rings occurred after brief periods of operation. Modifications to the engine (e.g. high top land, controlled pressure relief ring, semihoned wave cut liner, alpha lubricator) improved liner lubrication. The authors also set about improving the cylinder lubricant and developed a 40BN cylinder lubricant. This lubricant not only shows good cylinder lubricant performance, it also has good high-temperature oxidation stability and controls ash deposits. Cylinder lubricant performance is defined by detergency and anti-scuffing performance at high temperatures. Through use of a unique ash softening technology, this lubricant offered a perfect balance between high ash (which translates to high BN and high performance) and ash deposit control. This lubricant was in use for more than 20,000 hours until 2003.

该论文已在赫尔辛基举行的第28届CIMAC大会上发表，论文的版权归CIMAC所有。Exhaust emissions from marine diesel engines are considered to be one of the most significant contributors to air pollution. For this reason, NOx regulation and fuel sulphur limits have become increasingly strict. Clean alternative fuels are playing an increasingly important role in the internal combustion engine industry. Among them, natural gas is a preferred choice due to its abundant sources, clean combustion and low CO2 emission level. Recently, manifold multi-point gas injection technology was adopted by engine manufactures to improve the consistency of gas fuel supplied to each cylinder and response to load changes. However, the characteristics of manifold gas injection have a significant influence on combustion and emissions of marine lean-burn natural gas engines. It is therefore vital to investigate the effect of gas nozzle structures and gas injection control on in-cylinder mixture formation and the combustion process. In this study, numerical simulation techniques were adopted to analyse the influence of the nozzle structure on the intake mixture and combustion process in natural gas engine. The results show that for the marine lean burn natural gas engine with throttle, the design scheme of the cross multi-hole gas nozzle can improve the intake mixture and in-cylinder combustion at higher engine load. However, the structure of single-hole gas nozzle can provide higher kinetic energy and achieve rapid intake of gas fuel, which is beneficial to the in-cylinder mixture and stratification combustion at lower engine load. Based on the research results, some gas nozzle products we developed have been widely applied to the China inland river ships market.

该论文已在赫尔辛基举行的第28届CIMAC大会上发表，论文的版权归CIMAC所有。The seaborne transportation of Liquefied Natural Gas (LNG) is intensified, with the number of LNG carrier vessels sailing and on order steadily increasing. The current volatile global market and energy supply environment puts a pressure on LNG vessels to be more efficient, cost-effective and environmentally friendly. Modern LNG carriers feature complex and tightly integrated machinery systems to convert the on board primary energy sources to useful energy demands for propulsion, service electricity and heat. The main fuel source of LNG carrier is natural boil-off gas (BOG) from the cargo tanks with varying quantity and composition during voyage. The LNG ship energy system consists of various interdependent modules such as BOG compression trains, gas distribution and management, possible reliquefaction plant for the surplus BOG, prime movers, electricity generation / distribution networks as well as boilers for steam production. LNG carriers have also a time varying operational profile and trading patterns that affect LNG and BOG composition, hence affecting the energy efficiency of the integrated system. Therefore, the selection of the most suitable technologies and configurations for a particular ship is non trivial.

Development of Dual Fuel Engine 28AHX-DF Capable of FPP Direct DriveIn order to meet stringent exhaust emission regulation for marine engine, the alternative fuel is growing in usage and popularity. In particular, the market demand of gaseous fuel as typified by natural gas is heavy thanks to its high environmental adaptability and worldwide falling prices. According to this circumstance, Niigata has recently developed the dual fuel engine 28AHX-DF with advanced transient performance and thermal efficiency. 28AHX-DF engine is developed to apply to marine engine which directly drive the fixed pitch propeller. The reason comes from the fact that the effect of greenhouse gas reduction from marine gear direct drive is larger in comparison with electric propulsion which is affected by generator efficiency. In case of the direct drive propulsion, it is difficult to ensure the sufficient air delivery and the knocking might be occurred since the engine load is changed along the propeller law. Therefore, the combustion control technology and air/fuel control technology as countermeasure for this difficulty is required. 28AHX-DF engine with superior transient performance which allows load acceptance within fifteen second or so due to high performance control technology was delivered as main engine of a tugboat in 2014 and the operation has been begun in 2015.

该论文已在赫尔辛基举行的第28届CIMAC大会上发表，论文的版权归CIMAC所有。The pre ignition caused by lubricating oil has been becoming apparent with the increasing mean effective pressure more than approximately 1.8 MPa including the passenger car engines and one of the critical issues nowadays for the most premixed combustion engines because it could damage the engine with the remarkably high maximum firing pressure. This phenomenon could be the impediment to the improvement of the engine efficiency and the increase of mean effective pressure in the future development of engines because it becomes severer by increasing compression ratio and mean effective pressure. In consideration of the fact that this phenomenon is much more apparent on the industrial gas engines in Japanese market where the city gas with very low Methane Number is used, it is expected that this issue will be more common when LNG with the wide range of Methane Number will be used as the fuel of gas engines all over the world from now, especially in the marine application where Methane Number changes also depending on the tank level.

该论文已在赫尔辛基举行的第28届CIMAC大会上发表，论文的版权归CIMAC所有。In January 2013 CO2 emission regulation by IMO went into force and the Energy Efficiency Design Index (EEDI) was applied to indicate CO2 emission category of a ship. The value of EEDI is the result of several ship design selections, among them there is the selection of the engines: main and auxiliary. The EEDI is an index indicating the energy efficiency of vessels, therefore the EEDI becomes one of the important index of maritime diesel engines. In this view, YANMAR continues various researches and developments to achieve a substantial reduction of the fuel consumption for improving the value of EEDI. There are not many parameters influencing the fuel consumption, the most important are: the peak firing pressure, the air to fuel ratio, the Gas exchange work, the reduction of heat losses, the combustion process and the engine friction. In this paper YANMAR presents the result of a project based on the improving the gas exchange work, the combustion process.

该论文已在赫尔辛基举行的第28届CIMAC大会上发表，论文的版权归CIMAC所有。Mitsubishi UE engines feature high economic efficiency, high reliability, and environmental-friendliness. The high economic performance of the UE engine can save ship owner’s operating costs. Mitsubishi UE engines have been developed and improved for more than half a century. Now, the full lineup of the latest UEC-LSE series has been completed. Moreover electronically controlled engine, which is the UEC-Eco series, have also been in service since 2005 in order to comply with IMO-NOx Tier 2 regulations and market needs to save energy. Mitsubishi Heavy Industries Marine Machinery & Engine Co., Ltd. (MHI-MME) has developed a state-of-the-art low speed marine diesel engine that includes all of the advanced technologies which MHI-MME has accumulated over the years. The latest UE engine series was named UEC-LSH, with development of the first in the series -the UEC50LSHEco- finished. The production and shop testing of the first 6UEC50LSH-Eco was completed in March 2015. Comprehensive verification was carried out on such items as the engine’s performance, reliability and vibration, and the engine performance was optimized before being delivered to the customer. The vessel powered by the first UEC50LSH-Eco engine will be in service in September 2015, and it will be expected to prove the performance defined in its development concept.

该论文已在赫尔辛基举行的第28届CIMAC大会上发表，论文的版权归CIMAC所有。Under the International Maritime Organization (IMO) Tier III regulations, NOx emissions from ships sailing in an emission control area (ECA) should be reduced by more than 80% compared to the IMO Tier I level. An oxygen reduction membrane (ORM) system was recently developed in Japan by the Asahi Kasei Chemicals Corporation and has been receiving significant attention. This system reduces NOx emission by decreasing the oxygen concentration in the intake or scavenging air using a special membrane. The ORM system is set up on the intake or scavenging air side; therefore, the specific fuel properties (e.g. sulfur content) or fuel types (e.g. heavy fuel, marine diesel oil and gas fuel) are not a factor in the use of this system. Moreover, the system is operated using only air, so that there is no potential for environmental harm.

该论文已在赫尔辛基举行的第28届CIMAC大会上发表，论文的版权归CIMAC所有。Kawasaki Heavy Industries, Ltd (KHI) lines up KG series and KG-V series gas engine named as Kawasaki Green Gas Engine (GGE) and expand a sale in market, so the power range of 5.0 to 7.8MW is covered by 12,18 cylinder engines. KHI has already taken more than 75 sets orders in not only domestic market (Japan) but also over sea market. The delivery destinations are widely covered from a power plant of 100MW class to co-generation plant. GGE keeps both high electrical efficiency (Electrical efficiency :49.0%) and low NOx emission level, moreover GGE is widely to be operated from low road (30%) to high load and the electrical efficiency of the partial load is kept to high, then GGE is meet to various requirement by flexible operation range.