Mitsubishi Heavy Industries Marine Machinery & Engine Co., Ltd. (MHI-MME) has developed a new generation low-speed marine diesel engine, the UEC50LSH-Eco, for a wide output and speed range that includes the chemical tankers and Supramax and Handy-size Class bulk carriers and medium range tankers. The UEC50LSH-Eco has been developed on the principal design concepts of “high efficiency” and “environmental friendliness” and based on technologies accumulated from many years of technical development activities of Mitsubishi UE Engines. The UEC50LSH-Eco achieves extremely low SFOC (Specific Fuel Oil Consumption) owing to an improved trade-off relationship between SFOC and NOx obtained by an optimized fuel injection pressure and rate, reduction of mechanical loss, and high efficiency of the exhaust gas and scavenging air system. Moreover, further SFOC reduction can be achieved with Mitsubishi’s MET Turbocharger technologies. Recently, MHI-MME also released a new UEC-LSE series that includes the “UEC-Eco” electronically controlled engines, to comply with IMO-NOx Tier 2 regulations and market needs to save energy. All of these UE engines are in service and demonstrate excellent performance.
With the recent growing interest in natural gas fueled ships around the world, demands for marine diesel engines that serve this need are rapidly increasing. This paper explains the approach to dual fuel engines that Mitsubishi has taken with its UE low speed 2-stroke diesel engine named the UEC-LSGi. The UEC-LSGi has a high pressure natural gas injection system and runs on pilot fuel oil and natural gas. With natural gas combustion, UEC-LSGi delivers the same heat efficiency as that of a diesel engine while also reducing both NOx and CO2 emissions, which is a great advantage with regard to NOx regulations and EEDI. The UEC-LSGi operates in the same way as traditional diesel engines, that is, by means of diffusion combustion. Therefore, the UEC-LSGi can run in the gas mode without load limitations. Since natural gas does not contain sulfur and since the pilot fuel is used only minimally, UEC-LSGi emits very little SOx.
The environmental impact of gas engine emissions such as NOx, PM, SOx and CO2 is significantly lower than that of diesel engines. Furthermore, the cost of gaseous fuel is lower than that of heavy fuel, and this cost difference will continue to increase. Focusing on these advantages, the gas engine is expected to be used as a marine power source. On the other hand, in the practical application of gas engines to marine use, maintaining combustion stability during variation in load and fuel composition is a problem that needs to be considered. YANMAR has developed a new marine gas engine. This paper introduces the new engine profile and describes new technologies that addressed previously described problems.
At the MEPC66, it was decided that as of 2016, IMO Tier III regulations would require nitrogen oxides (NOx) reductions of approx. 76% from Tier II levels. To comply with IMO Tier III regulations, we have developed a low pressure Exhaust Gas Recirculation (LP-EGR) system that has strong NOx reduction potential. It has been confirmed through studies using our 4UE-X3 test engine that the NOx emissions of our LP-EGR system comply with IMO Tier III regulations and that the increase in fuel consumption was less than 1.5%. Recently, an engine integrating almost every component of the LP-EGR system was applied to the 4UE-X3. Through tests and evaluations of this system, we carefully worked out the consumption volumes and life-cycle costs of our LP-EGR system. As a result, the system is IMO Tier III regulation-compliant and offers advanced environmental protection and user-benefits.
This study aims to investigate the potential of a 2-stage turbocharging system to reduce NOx emission. First, 1D cycle simulation model implementing high boost pressure, which imitates 2-stage turbocharging system, was calculated, and it was confirmed that with the combination of early intake valve closing, there is a potential to reduce NOx from conventional single turbocharging engine model without any fuel consumption penalty. Then, the 2-stage turbocharging system was coupled to a medium speed 6-cylinder experimental diesel engine, and test runs were carried out to confirm the potential. Results of the test run show that 2-stage turbocharging system has the potential to reduce NOx as estimated, and as a co-product, BSFC improvement was confirmed when allowing Tier II level NOx emission. Furthermore, engine output increment was possible, without deteriorating BSFC-NOx trade-off relationship. Further development is planned to meet IMO NOx Tier III regulation.
Niigata Power Systems has been developing the gas engine for about 30 years as one of the best matched products which satisfies the trend of social requirements, such as an environmental preservation and fuel economy, and an electrical demand in industrial field.
Niigata developed new gas engine for marine which is called dual fuel engine used two-type of fuel, oil and gas.
The marine dual fuel engine was designed through diesel design experience and micro pilot technology for diesel mode operation and gas mode operation respectively. Niigata developed the propeller direct drive type dual fuel engine which can meet the desired load operation characteristics coming from the tugboat which works in harbor without generating abnormal combustion such as a knock, with original combustion technology.
Sudden acceleration torque and slowdown torque are required of a tugboat at the time of navigation of a large-sized ship.
Moreover, Niigata Dual fuel engine meets NOx emission level in IMO TierⅡ and TierⅢ at diesel operation and gas operation respectively. This performance can be accepted in ECA area.
Maritime accident is an issue of immense concern across the globe particularly because of its effect on environment and human lives. In general, there are many contributing factors behind maritime accidents, yet failure of marine engine is regarded as one of the main contributing factors. This paper, therefore, focuses on maritime accident due to engine failure. Literature review suggest that a wide range of accident theories have been developed over the years which can explain the causes of accidents. Nevertheless, there exist a significant deficiencies in computational techniques of accident prediction and analysis. Therefore, the authors attempted to present a new method named Logic Programming Technique (LPT). A simple modelling architecture is proposed which essentially utilizes search techniques to deduce an accident with sequence of events associated with engine failure. In this paper, a static knowledge base is constructed following two actual marine accident cases in order to explicate the concept. The research findings suggest that this technique has the potential to dig deep into the accident sequence and find out the root causes. Future challenges for developing this technique are discussed and research on further advancements are recommended.
Electric propulsion systems are found to be a more effective way of propulsion, especially in several applications such as supply vessels, shuttle-tankers, ice-breakers, etc., where a varying velocity profile is preferred. At the same time, the conventional design includes inverters to control propeller rotational speed and/or controllable pitch propeller, thus making the total system very expensive, complex and with additional space requirements. In this study, the authors propose a novel concept of electric propulsion direct drive consisting of a diesel engine and a synchronous generator which directly feeds the induction motor connected to a fixed pitch propeller. By changing the voltage applied to field windings of the generator and rotational speed of the diesel engine an inverter like control of propulsion motor rotational speed can be achieved. This paper presents general concept of a Direct Drive Electric Propulsion (DDEP) system and the simulation results of a complete diesel-electric propulsion system model.
To address environmental concerns regarding sulfur oxides, IMO is implementing a continuous reduction in the sulfur content of heavy fuel oils. This should also limit the amount of acid production during the combustion process, which contributes to the corrosion control of moving surfaces in a 2-stroke engine. However, there are other environmental (NOx emission reduction) and economic (energy efficiency) factors that play a major role in the marine industry. New energy efficient engines are imposing severe operating conditions with ultra-long strokes, and higher pressures. Slow steaming operation also leads to extremely cold corrosive conditions in the engine.
TOTAL has designed a corrosion test evaluating the ability of the cylinder lubricant to protect metallic surfaces against cold corrosion by sulfuric acid. Acid neutralization conditions of the test have been studied in detail. We show how this very effective test procedure has contributed to the development of our cylinder lubricants and to the understanding of the protection of moving surfaces.
Thermal characteristics of phase change materials (PCMs) were investigated experimentally to construct a fundamental database of thermal storage systems for waste heat recovery in this study. Sodium acetate trihydrate and D-mannitol which have relatively high latent heats were selected as PCMs. The heat inputs from a cartridge heater were varied from 5 to 15 W in the experiment. As a result, thermal stratification appeared in the vertical direction in the case of sodium acetate trihydrate. On the other hand, the temperature distribution of D-mannitol was not stratified because of the weaker natural convection than the case of sodium acetate trihydrate. Also, the solidification characteristics were investigated in this study. It was clarified that the degree of super cooling of D-mannitol was lower than that of sodium acetate trihydate. In addition, the thermal analyses of the chosen PCMs were conducted by thermogravimetric and differential thermal analysis (TG-DTA). Results of DTA show that the down peak of D-Mannitol was lower than that of sodium acetate trihydrate. Furthermore, the TG of D-Mannitol did not decrease at temperatures of 298.15 K to 458.15K.
A deep understanding of transient pool boiling heat transfer and critical heat flux (CHF) phenomena in water is important as a fundamental knowledge for the innovative design of liquid cooling technologies. Transient CHF due to exponentially increasing heat inputs, Q=Q0 exp(t/τ, to platinum ribbon in pool of water was measured for saturated conditions at atmospheric pressure. The exponential period, τ, was varied from 5 ms to 20 s. The platinum ribbons having different surface conditions, namely, commercial surface (CS), treated surface-I (TS-I) and treated surface-II (TS-II) were utilized as test heaters. For surface conditions, the values of contact angle and surface roughness were measured prior to pool boiling experiments. The TS-II was subjected to conditions without pre-pressurization and with pre-pressurization up to 4.4 MPa before each experimental run was carried out. It is assumed that the contact angle is a major contributor to increasing CHF at quasi-steadily heat input. The TS-II enhanced the heat transfer performance ∼ 290 % and ∼ 430 %, and CHF of 1.2 times and 1.5 times relative to CS and TS-I, respectively. It was shown that transition of heat transfer processes and transient CHF depend on surface conditions, heat generation period and pre-pressurization. The transient CHF due to surface conditions was compared with corresponding values.
Detailed understanding of generalized saturated and subcooled pool boiling CHF (Critical Heat Flux) phenomena is very important for the design and the safety assessment such as those in high heat flux cooling systems using subcooled water pool boiling, in the super-conducting magnets cooled by liquid helium and liquid nitrogen, and in the thermal control of microelectronic assemblies for future super-computers cooled by Fluorinert liquid FC-72. The objective of this work is to clarify the effect of the pressures, subcoolings, and periods on pool boiling CHF, and is to elucidate the generalized phenomena at steady and transient CHF depending on the wettability of boiling liquids. The CHF data were considerably explained by a boiling liquid approach and its property. Photographic observations of the vapor bubble behavior during film boiling transitions were also performed using a high-speed video camera system.
In this study, bio-butanol soluble in bunker A is examined to use as a marine diesel fuel. The effects of 1-butanol blending ratio to bunker A on the fuel properties, ignitability, combustion characteristics and exhaust emissions are investigated using a single cylinder DI diesel engine. The blending ratio of 1-butanol is varied from 10 mass% to 40 mass%. The experimental results show the ignition delay of the blended fuel becomes longer and the HC and CO emissions increase especially at low load conditions with the 1-butanol content. With 30 mass% 1-butanol blends, the thermal efficiency of 1-butanol blend is almost the same as that of bunker A and the smoke emission reduces by about 50 % at full load condition.