Specific Fuel Oil Consumption Research Articles

Maritime DC Power System With Generation Topology Consisting of Combination of Permanent Magnet Generator and Diode Rectifier

The dc grid is emerging as a new electric power distribution concept for several types of vessels due to its higher fuel efficiency compared with the conventional ac grid. Until today, wound rotor generators (WRGs) and diode rectifiers have been applied to the generation part of the onboard dc grid although the efficiency, weight, reliability, and footprint of the WRGs are inferior to those of permanent magnet generators (PMGs). In this article, the possibility of adopting the PMG in the onboard dc grid instead of the WRG is studied. According to the analysis, even though the PMG is inherently incapable of adjusting rotor flux, the rectified dc voltage can be controlled in a certain range under all load conditions. Simultaneously, the diesel engine can be controlled near its optimal operating line (OOL) to minimize fuel consumption. The controllability of the rectified dc voltage of the PMG is verified by computer simulation and small-scaled experimental tests. When comparing the operating trace of the proposed system to the specific fuel oil consumption (SFOC) map of a 350-kW diesel engine, i.e., AD158TI, the fuel-saving by applying the PMG is expected to be more than 10% at light load condition and around 3% average in overall operating conditions.

디젤기관의 바이오연료 혼합율 및 바이오 온도변화 대한 배출가스 특성 연구

Biofuels are a form of renewable energy and vigorously require research to cope with the changes in international energy supply and demand. Although they only account for a few percent of the worlds transport fuel to date, they are increasingly popular due to higher oil prices and an increasing concern with global warming and investments into them are therefore growing each year. Biofuels are renewable energy and need to be continuously researched to deal with changes in international energy. Therefore, the authors intended to investigate varying biodiesel fuel ratios and biodiesel fuel temperatures to present various uses for biofuels. Engine experiments were conducted with fixed fuel injection timing of BTDC 22°CA using a four-stroke six-cylinder in a direct injection diesel engine. The results of this study demonstrated that as the biodiesel fuel mixture increased, fuel consumption increased slightly, NOx increased, CO decreased slightly, and PM decreased significantly. When the biofuel temperature changed, NOx and PM increased slightly, brake specific fuel oil consumption increased and CO did not change significantly.

A Novel Telemetry System for Real Time, Ship Main Propulsion Power Measurement.

Modern ships are required to increase the energy efficiency and minimize fuel consumption. This paper presents the construction, main properties and exemplary measurement results of a novel system intended for main shaft power monitoring. The telemetry system consists of the stationary part, responsible for wireless supply energy transfer to the rotating part. Additional functions of the stationery unit include radio-based, bidirectional communication with the rotating, microcontroller-based unit, and Modbus-based communication with the graphical user interface. The non-stationary (rotating) part receives the necessary energy using the wireless transmission and performs the torque and speed measurement using strain gauge and a special setup of the wireless energy system. A novel system of flexible printed circuit board (PCB) coils is used for wireless energy transmission and increases the flexibility of the device while minimizing the necessary size, weight, and costs of the setup. The microcontroller unit used for measurements allows proper sampling of highly dynamic signals and can be used for advanced drive system diagnostics or as a typical power monitoring device. Such unit was installed on a ferry and operation was monitored for several sea trips. Main results depict characteristic power data referenced to vessel speed and specific fuel oil consumption (SFOC). Proposed system construction allows to reduce system costs and provides stable readings for long period of operation.

Quantifying the fuel consumption, greenhouse gas emissions and air pollution of a potential commercial manganese nodule mining operation

Manganese nodules contain economically valuable metals which may be mined in the future to supply metals to a growing world population. Thus far, environmental research has focused mainly on impacts occurring at the seafloor or in the water column but largely neglected any impacts caused above the sea surface. Emissions of greenhouse gases and other air pollutants contribute to, inter alia, global warming, acidification and photochemical ozone formation, which all negatively affect ecosystems and humans. We quantify the annual fuel consumption and emissions associated with a potential nodule mining operation in the Clarion-Clipperton Zone with an annual production of 3 million dry tons. We base the assessment on publicly-accessible energy demand estimates from three different studies and complement this with a calculation of the fuel demand and emissions of nodule transport scenarios to three different destinations. The global warming, acidification and photochemical ozone formation potentials range between 82,600–482,000 t CO2-equivalent (-eq.), 1,880–11,197 t SO2-eq., and 1,390–8,734 t NOx-eq., respectively, depending on factors including the engine loads, specific fuel oil consumption and transport speeds. We then discuss the regulatory dimension surrounding the topic. As three separate regimes (climate change, deep-sea mining and shipping) are applicable, we analyze the applicable framework and provide an outlook for the future regulation of DSM-related GHG emissions.

A multi-level optimization technique based on fuel consumption and energy index in early-stage ship design

Reducing lifetime fuel consumption (LFC) and energy efficiency design index (EEDI) are two of the main concerns of shipping industry in recent years. This paper presents a multi-disciplinary and multi-level optimization scheme-based software (HPS-MOP2) to design a hull–propeller system simultaneously from the LFC and EEDI point of view in early-stage ship design. Calculations of the ship resistance and propeller performance are essential to optimize the ship hull–propeller system. Two numerical methods with variable fidelity, non-uniform rational basis spline (NURBS) geometry modelling technique and new version of multi-objective evolutionary algorithm based on decomposition (MOEA/D) are three main parts of the proposed methodology. A bulk carrier propelled by a well-known propeller is used as a base model in three different study cases based on specific fuel oil consumption (SFOC) curves provided by the engine manufacturers Wartsila, MAN and Caterpillar. The presented results illustrate that the employed approach may achieve cost- and energy-efficient designs.

An experimental investigation on the effects of fuel additive on the exhaust emissions of a ferry

This study experimentally investigates the effects of fuel additive on the exhaust emissions and performance of a marine diesel engine installed on a ferry. The fuel additive consisting of hydrocarbon solution of cyclic and aliphatic amino compounds is used to blend the ultra-low-sulfur diesel fuel. On-board measurements of NOx, SO2, CO2, CO, hydrocarbon and particulate matter emissions with and without fuel additive were carried out at different engine loads. The composition and formation of the particles are studied by using scanning electron microscopy/energy-dispersive X-ray spectroscopy analysis. The results show that the fuel additive reduced the emissions of CO, hydrocarbon and particulate matter by 6.5%, 60% and 38%, respectively. The elemental analysis of particles indicates that there are 13 major elements such as C, O, Na, Mg, Al, Si, S, K, Ca, Ti, V, Zn and Fe in the samples. Considering the type of the fuel, the Ca, Fe and N are thought to come mainly from the fuel additive. The composition and components of the diesel particles and also the specific fuel oil consumption are not affected significantly by the fuel additive. Consequently, the fuel additive improves the combustion performance and reduces the CO, hydrocarbon and particulate matter emissions of the engine.

Application of a variable-fidelity hydrodynamic optimization strategy in fuel-efficient ship design

Now more than ever, the amount of fuel a ship consumes and the amount of carbon dioxide emitted from a ship have attracted many researchers’ attention towards efficient and cost-effective ship designs. Therefore, fuel consumption and carbon dioxide emission reduction are two main targets of almost all industrial and scientific communities. The key scope of this article is to describe an innovative methodology for the variable-fidelity design optimization of a ship’s hull-propeller system under multiple operating conditions in early-stage ship design. Non-uniform rational basis spline technique and the efficient multi-objective evolutionary algorithm based on decomposition are, respectively, used to generate variants of hull-propeller designs and minimize the fuel consumption and carbon dioxide emission as objective functions of the proposed problem. The variable fidelity numerical solvers are also applied for the hydrodynamic evaluation of the design performance during optimization. Three different specific fuel oil consumption data provided by the engine manufacturers Wartsila, MAN B&W and Caterpillar are used to optimize a medium-sized bulk carrier driven by a well-known propeller as the initial design. The numerical results show an improvement in performance of the optimal hull-propeller designs.

Power management optimization of hybrid power systems in electric ferries

The integration of more-electric technologies, such as energy storage systems (ESSs) and electric propulsion, has gained attention in recent years as a promising approach to reduce fuel consumption and emissions in the maritime industry. In this context, hybrid power systems (HPSs) with direct current (DC) distribution are currently gaining a commendable interest in research and industrial applications. This paper examines the impact of using HPS with DC distribution and a battery energy storage system (BESS) over a conventional AC power system for short haul roll-on/roll-off (RORO) ferries. An electric ferry with a HPS is modeled in this study and the power management system is simulated using the Matlab/Simulink software. The result is validated using measured load profile of a ferry. The performance of the DC HPS is compared with the conventional AC system based on fuel consumption and emission reductions. An approach to estimate the fuel consumption of the diesel engine through calculation of specific fuel oil consumption (SFOC) is also presented. This study uses two optimization techniques: a classical power management method namely Rule-Based control (RB) and a meta-heuristic power management method known as Grey Wolf Optimization (GWO) to optimally manage the power sharing of the proposed HPS. Fuel consumption and emission indicators are also used to assess the performance of the two power management methods. The simulation results show that the HPS provides a 2.91% and 7.48% fuel consumption reduction using RB method and GWO method respectively. It is apparent from the result that the HPS has more fuel savings while running the diesel generator sets (DGs) at higher operational efficiency. It is interesting that the proposed HPS using both power management methods provided a 100% emission reduction at berth. Finally, it was found that using a meta-heuristic optimization algorithm provides better fuel and emission reductions than a classical method.

Modeling and Real-Time Scheduling of DC Platform Supply Vessel for Fuel Efficient Operation

DC marine architecture integrated with variable speed diesel generators (DGs) has garnered the attention of the researchers primarily because of its ability to deliver fuel efficient operation. This paper aims in modeling and to autonomously perform real-time load scheduling of dc platform supply vessel (PSV) with an objective to minimize specific fuel oil consumption (SFOC) for better fuel efficiency. Focus has been on the modeling of various components and control routines, which are envisaged to be an integral part of dc PSVs. Integration with photovoltaic-based energy storage system (ESS) has been considered as an option to cater for the short time load transients. In this context, this paper proposes a real-time transient simulation scheme, which comprises of optimized generation scheduling of generators and ESS using dc optimal power flow algorithm. This framework considers real dynamics of dc PSV during various marine operations with possible contingency scenarios, such as outage of generation systems, abrupt load changes, and unavailability of ESS. The proposed modeling and control routines with real-time transient simulation scheme have been validated utilizing the real-time marine simulation platform. The results indicate that the coordinated treatment of renewable based ESS with DGs operating with optimized speed yields better fuel savings. This has been observed in improved SFOC operating trajectory for critical marine missions. Furthermore, SFOC minimization at multiple suboptimal points with its treatment in the real-time marine system is also highlighted.

Shuttle tanker fuel consumption numerical analysis for improving ship efficiency

The fuel consumption analysis of a Suezmax tanker customized to the offloading operation in the brazilian coast is performed in order to verify the possible savings produced by the so-called “slow steaming” technique during navigation. This ship is equipped of a single engine/propeller but there is a trend of building new vessels considering an equivalent two engines–two propellers for better safety during navigation and offloading operations, therefore a comparison regarding the propulsive efficiency, fuel consumption, and operational conditions (max engine power, rotation, and cavitation limitations) is performed in order to verify the benefits of this new concept. The methodology applied is based on a mixed approach considering numerical simulations using CFD (computational fluid dynamics) and regression models available in the literature: the first one applied to compute the ship resistance and nominal wake fraction in the propeller plane and the second one applied for the propulsive efficiency prediction, as the propeller curves based on Wageningen B-series. The specific fuel oil consumption curves were obtained from the engine manufacturer catalogue.

Reducing emissions by optimising the fuel injector match with the combustion chamber geometry for a marine medium-speed diesel engine

The effects of seven matching parameters of a fuel injector and combustion chamber geometries on nitrogen oxide (NOx), soot and specific fuel oil consumption (SFOC) were investigated by means of a parametric study. The study was carried out on four different engine loads, i.e. L25 (25%), L50 (50%), L75 (75%) and L100 (100%) loads. The injection-related parameters were found to have more prominent influences as opposed to the combustion chamber geometries. Then, a multi-objective genetic algorithm (MOGA) method was proposed in order to identify a set of optimal designs for the L100 load. The emissions and performance of these optimal designs were also examined and compared on the other three engine loads. Finally, an optimal design which meets the IMO (International Maritime Organization) Tier II NOx emissions regulations (research shows it is impossible to meet Tier III NOx emissions regulations solely on the basis of the optimisation of the combustion progress) and which has the best fuel economy was singled out.

Approaches to Economic Energy Management in Diesel–Electric Marine Vessels

Recently, the efficiency of diesel–electric marine vessels has been subject for discussion with focus on improving fuel efficiency, reducing the environmental footprint from emissions, as well as reducing running hours and maintenance costs. This paper presents an analysis of load profiles extracted from three different vessels during operation: 1) a ferry; 2) a platform supply vessel; and 3) a seismic survey vessel. The analysis of the extracted data shows that the loadings of the diesel engines are typically quite low, and do not fall within the optimal loading range of diesel engines’ specific fuel oil consumption curves. Furthermore, three different power plant configurations are proposed and compared, which include fixed-speed (diesel engine generators) and variable-speed gensets and the implementation of an energy storage system. Moreover, energy management system (EMS) algorithms based on mixed-integer linear programming (MILP) are proposed as a suitable strategy for optimal unit commitment in the power generation. The results yielded from the MILP algorithms are compared with those from the EMS algorithms based on logic such as if/else statements. The results indicate that optimal EMS algorithms in combination with a revised vessel configuration can increase the operational efficiency, in terms of fuel savings and reduction in genset running hours.

Enhancing Fuel Efficiency and Environmental Specifications of a Marine Diesel When using Fuel Additives

Objectives: The article is aimed at discussing the results of application of marine motor fuel additives. Method: A method for improving fuel performance properties by applying fuel additives has been proposed. A 6N21L medium-speed fourstroke cycle diesel by Yanmar was used for this research. A RME25 marine fuel, viscosity of 25 sSt at 100oC and sulphur content of 2.8 w.w%, was applied. An additive containing active oxygen-bearing groups and modified with light metal salts was used as a fuel additive. Findings: Experiments were done, using three diesels of the same type, which allowed for one diesel to run on the basic fuel, and for feeding the additive-containing fuel into cylinders of two other diesels (following additional equipment of the fuel system with a flow meter and a dispenser). Specific fuel oil consumption, exit gas temperature, NOx and SOx concentration in the exit gases, and technical condition of fuel system and cylinderpiston group elements were determined in this experiment. It was shown that the use of fuel additives improves fuel efficiency of a marine diesel, in particular reduces specific fuel oil consumption by 3.5 to 5.8% subject to diesel load and additive concentration in the fuel. Improved environmental performance of the diesel, i.e. NOx reduction by 1.4 to 4.3% and SOx reduction by 15.6 to 22.9% in exit gases, was also found. It was shown that additive concentration is of optimal importance, can be determined experimentally and depends on diesel and fuel specification. Improvements: Improved technical condition of diesel cylinder-piston group and gas outlet system elements was determined as a result of visual inspection, thus reducing work labor input for diesel purging by 20 to 25%.

Reduction of Fuel Consumption on Hybrid Marine Power Plants by Strategic Loading With Energy Storage Devices

Recent advances in energy storage devices (ESDs) technology have enabled new guidance strategies for power generation and distribution on hybrid marine power plants, supported by new class regulations. In this paper, a new model to calculate the fuel saving and emission reduction potential is derived based on the ESD maximum charge/discharge rate, engine efficiency, and specific fuel oil consumption (SFOC) curve. Several cases were analyzed with generator disconnection and also without it. Spline approximation for the discrete fuel oil consumption curve is used for numerical solution and later optimized using the Karush–Kuhn–Tucker method. A second approach is proposed, using linear interpolation, reducing the optimization process computational time. It is shown that fuel savings can be increased and emissions reduced by charging and discharging the energy storage device. This is denoted as strategic loading according to the proposed model. The cases with highest potential for fuel saving are shown to be cases where generators are disconnected.

Optimization of blending oil with non-esterified biodiesel fuel using design of experiment at partial engine loads

Non-esterified bio-diesel fuel is more economically feasible than esterified one because of simple manufacturing process that only consists of filtering. Applicability of this fuel on diesel engine with electronic control system was tried and accomplished in a previous research. In this study, optimization adopting a fractional factorial design and response surface methodology was carried out at 25 % and 50 % of engine load in order to verify effectiveness of design of experiment for performance optimization of diesel engine. Pcr and IT mainly affected responses as specific fuel oil consumption and nitrogen oxides regardless of engine load according to the fractional factorial design. Estimations were 310.3 g/kWh of specific fuel oil consumption and 237 ppm of nitrogen oxides at 25 % load, and 233.2 g/kWh of specific fuel oil consumption and 730 ppm of nitrogen oxides at 50 % load according to the response surface methodology. As the results of verification tests, specific fuel oil consumption and NOx were respectively 300.4 g/kWh and 277 ppm at 25 % load, and 236.8 g/kWh and 573 ppm at 50 % load. Since there were small differences between estimations and verifications, adopting Box-Behnken method of the response surface methodology for performance optimization of diesel engine should be considered carefully.

Comparison of fuel consumption and emission characteristics of various marine heavy fuel additives

Major shipping companies utilize fuel oil additives to reduce fuel costs and to comply with emission regulations. Although the use of fuel additives for marine heavy fuel oil has increased dramatically, their effects on performance have not been verified. This study investigated the effects of fuel additives, not only at the scale of the engine test bed but also through chemical laboratory tests. Fuel separability tests were conducted to evaluate fuel oil stability. The results indicated that there was improved stability with certain dosages of fuel additives. Fuel combustion and ignition characteristics were evaluated via a Fuel Combustion Analysis (FCA) test, which showed that combustion parameters, including the pressure trace and rate of heat release (ROHR), were significantly affected by the use of fuel additives. The ROHR results showed modified performance indicators, particularly in regard to the position of the ROHR, ignition delay, end of main combustion, and end of combustion. The testing only aimed to determine the tendency at low engine loads, because engines typically operate at low loads within emission controlled areas. The engine test results showed that some additives were associated with reduced fuel consumption, but that some resulted in higher specific fuel oil consumption levels than those for fuel oils without additives. Nitrogen oxide (NOx) and particulate matter (PM) emission characteristics were also investigated, and data revealed that fuel additives affected the emission components.

Decreasing NOx of a Low-Speed Two-Stroke Marine Diesel Engine by Using In-Cylinder Emission Control Measures

The authors applied one-dimensional (1-D) simulation and 3-D Computational Fluid Dynamics (CFD) simulation to evaluate the potential of in-cylinder control methods on a low-speed 2-stroke marine engine to reach the International Maritime Organization (IMO) Tier 3 NOx emissions standards. Reducing the combustion temperature is an important in-cylinder measure to decrease NOx emissions of marine diesel engines. Miller-cycle and Exhaust Gas Recirculation (EGR) are effective methods to reduce the maximum combustion temperature and accordingly decrease NOx emissions. The authors’ calculation results indicate that with a combination of 2-stage turbocharging, a mild Miller-cycle and 10% EGR rate, the NOx emissions can be decreased by 48% without the increased Specific Fuel Oil Consumption (SFOC) penalties; with a medium Miller-cycle and 10% EGR, NOx can be decreased by 56% with a slight increase of SFOC; with a medium Miller-cycle and 20% EGR, NOx can be decreased by 77% and meet IMO Tier 3 standards, but with the high price of a considerable increase of SFOC. The first two schemes are promising to meet IMO Tier 3 standards with good fuel economy if other techniques are combined.

Effects of Fuel Post-Injection on the Performance and Pollutant Emissions of a Large Marine Engine

AbstractEmission reduction from marine engines can be supported by implementing multiple injection strategies. In the present study, the effect of fuel post-injection on the performance and exhaust emissions of a large two-stroke marine diesel engine is investigated by using computational fluid dynamics (CFD). An optimization procedure is formulated by coupling a KIVA-3-based CFD code with an optimization tool based on evolutionary algorithms (EAs). A fuel-injection profile consisting of two pulses (main and post-injection) is considered and parameterized in terms of four design variables. The specific fuel oil consumption (SFOC) and the final concentration of nitric oxides (NOX) and soot constitute the objective functions. Using a parametric study, two multiobjective optimization problems are formulated, an unconstrained and a constrained one; in the latter, the work output per engine cycle and the maximum in-cylinder pressure are the problem constraints. For both problems, significant reductions in poll...

선박용 디젤엔진에서 이단지연분사에 따른 배기 배출물 저감에 관한 실험 연구

Marine Environment Protection Committee of the International Maritime Organization has decided to reinforce the NOx emission standards for ships passing an ECA(Emission Control Area) with Tier III standards from January 1, 2016. In this study, real-time measurements of the exhaust gas, cylinder pressure and fuel consumption were conducted at each load of a T/S Hanbada main engine of Korea Maritime and Ocean University, which is controlled by single injection and double post injection for reducing NOx emissions. The results showed that the quantity of CO2 and NOx increased in proportion to the engine load, whereas the CO concentration was inversely proportional to the engine load. In addition, double post injection decreased 10 % of P-max and reduced 25~30 % of the NOx emissions compared to single injection, whereas there was a trade-off relation, such as increase 3~5 % of SFOC (Specific Fuel Oil Consumption).

Application of a multi-zone combustion model to investigate the NOx reduction potential of two-stroke marine diesel engines using EGR

The most promising solution for propulsion of marine vessels currently and for the near future is the two-stroke low-speed diesel engines. Despite its advantages, as far as specific fuel oil consumption, power density and reliability is concerned, it suffers from increased NOx emissions mainly because of its low rotational speed. But the upcoming NOx emission legislation (Tier III) in the marine sector requires considerable reduction of NOx emissions towards levels which have not yet been commercially achieved using primary methods. This creates new challenges for the development and application of innovative techniques that could reduce engine’s NOx emissions with the lowest possible fuel penalty. This is important considering current and future fuel prices. The large size of the 2-stroke marine engine makes the use of experimental techniques, to investigate this potential, expensive and time consuming. Modelling can significantly contribute towards this effort and result to reduction of research and development cost. Among the most effective in-cylinder techniques for NOx reduction is EGR, a proven technology for smaller engines used in the transport sector. In the present study, it is investigated via modelling, the potential to reduce NOx emissions of two-stroke marine engines using EGR. Despite the technological difficulties resulting mainly from the use of Heavy Fuel Oil (HFO), which makes the application of conventional EGR techniques difficult, it is worthwhile investigating the NOx reduction potential, since significant progress has been achieved towards the development of new EGR gas cooling techniques and scrubber technologies for removal of sulphur species from the exhaust gas. The present investigation makes use of an existing well validated multi-zone combustion model, initially developed for high-speed DI diesel engines. The model has been successfully applied in the past, to investigate heavy duty diesel engine NOx reduction via EGR, providing favourable results. Currently it is modified and applied on a two-stroke marine diesel engine using EGR. Model evaluation is based on experimental data acquired from the international literature, due to lack of experimental data for 2-stroke engines. The analysis of derived results reveals model’s ability to predict both engine performance and NOx emissions but most important the ability to predict the overall effect of EGR on NOx emissions in a qualitatively correct way. The results also reveal the strong potential of EGR to control NOx emissions of 2-stroke engines with relatively low fuel penalty compared to alternative techniques.