Specific Fuel Oil Consumption Research Articles

Propeller and Engine Performance of Commercial Windships: Benefits and Trade-Offs

_ Wind propulsion systems (WPS) for commercial ships can be a key ingredient to achieving the IMO green targets. Most WPS installations will operate in conjunction with propellers and marine engines in a hybrid mode, which will affect their performance. The present paper presents the development of a generic, fast, and easy tool to predict the propeller and engine performance variation, along with the cost, as a function of the wind power installed in two operation conditions: fixed ship speed and constant shaft speed. Specific focus is directed toward showing generic trends and trade-offs that inform economic decision-making. To this end, a key feature of the presented work is the ability to assess the cost–benefit of both controllable pitch propellers and fixed pitch propellers (CPPs and FPPs). This provides advice on when, in terms of WPS installation size, it is worthwhile to install which kind of propeller. CPPs are found to be more suitable for newly built wind-powered ships (>70% wind power), while a conventional FPP is satisfactory for wind-assisted ships (<70% wind power) and retrofitted installations. The results for a 91,373 GT bulk carrier showed that a WPS unloads the propeller and the engine, which leads to an increase in the propulsive efficiency and a detrimental rise of the engine specific fuel oil consumption. However, propeller gains are found to be greater than engine losses, which result in extra savings. Thus, not only does a WPS save fuel and corresponding pollutant emissions, but it also increases the entire propulsive efficiency. Keywords Windship; sailing ship; wind propulsion technologies; propulsion; performance prediction; marine engines; decarbonization; alternative propulsion

Specific Fuel Oil Consumption Models for Simulating Energy Consumption of Wellboats

Specific Fuel Oil Consumption Models for Simulating Energy Consumption of Wellboats

Coastal Air Quality Assessment through AIS-Based Vessel Emissions: A Daesan Port Case Study

Coastal regions worldwide face increasing air pollution due to maritime activities. This technical note focuses on assessing the air pollution in the Daesan port area, Republic of Korea, using hourly emission measurements. Leveraging Automatic Identification System (AIS) data, we estimate vessel-induced air pollutant emissions and correlate them with real-time measurements. Vessel navigational statuses are categorized from the AIS data, enabling an estimation of fuel oil consumption. Random Forest models predict specific fuel oil consumption and maximum continuous ratings for vessels with unknown engine details. Using emission factors, we calculate the emissions (CO2, NO2, SO2, PM-10, and PM-2.5) from vessels visiting the port. These estimates are compared with actual air pollutant concentrations, revealing a qualitative relationship with an average correlation coefficient of approximately 0.33.

Impacts of Charge Air Parameters on Combustion and Emission Characteristics of a Diesel Marine Engine

In this study, the operating processes of a four-stroke diesel marine engine from the intake valve closing (IVC) to the exhaust valve opening (EVO) at numerous different charge air conditions were simulated with the AVL FIRE code. The CFD models were validated with engine shop-test technical data. The results showed that increasing the charge air pressure without cooling decreased the actual amount of air supplied to the cylinder. As a result, the combustion process was suboptimal, resulting in a reduction in engine power and an increase in specific fuel oil consumption (SFOC). In addition, less air to cool the combustion chamber coupled with elevated charge air temperatures increased the in-cylinder peak temperature, leading to a significant increase in thermal nitric oxide (NO) emissions. In contrast, by cooling the charge air after turbocharging, the actual amount of air entering the engine cylinders was increased. The abundant charge air helped to cool the combustion chamber better, significantly reducing the in-cylinder peak temperature and then the thermal NO formation. Better combustion also increased engine power, which, in turn, reduced SFOC. In addition, carbon dioxide (CO2) and soot emissions were also reduced.

Influence of Valve-Seat Angles to Operation Values and Emissions of Medium-Speed Diesel Engines

Abstract For the development of gas exchange for large diesel engines, a compromise has to be found between efficient valve-flow and the time between overhauls. On the one hand, large effective flow areas, especially during valve-overlap, are demanded. On the other hand, there are limitations of cylinder bore regarding the maximum diameter of inlet and outlet valves and the minimum distance (dead space) between valves and piston, as well as wear-related smaller seat angles. For large medium-speed diesel engines, a valve-seat angle of β = 30° for inlet and outlet valves is a standard application. For engine-operation with clean fuels, a valve-seat lubrication (gasoil) or smaller seat angles (natural gas) need to be applied. With this presentation, the basic influence of different valve-seat angles on the operation values and emissions will be considered for the example of the single-cylinder research engine FM16/24. Using a self-developed testbed, experimental investigations into effective flow areas as a function of valve-lift at inlet and outlet valves have to be executed. With this input, different cycle calculations including T/C have to be carried out to determine deviances in specific fuel-oil consumption, exhaust-gas temperatures, NOx emissions and air/fuel ratio. The results will be discussed critically.

Effects of Piston Bowl Geometry on Combustion and Emissions of a Four-Stroke Heavy-Duty Diesel Marine Engine

Piston bowl geometry plays an important role in the fuel/air mixing quality which has a direct influence on the performance and emission characteristics of the engine. This work studied the effects of piston bowl geometry on the combustion and emissions of a four-stroke direct injection (DI) heavy-duty diesel marine engine. Three types of piston bowls with various parameters were numerically investigated, targeting to improve engine performance, fuel oil consumption, and emission characteristics. The results pointed out that the ω-type and re-entrant piston bowls enhanced cylinder power by 1.26% and 2.67% while reducing the indicated specific fuel oil consumption (ISFOC) of the engine by 1.06% and 1.60%, respectively, compared to the U-type bowl. Especially, the ω-type and re-entrant piston bowls reduced NO (nitric oxide) emission by up to 25.61% and 46.09%, respectively, owing to lower peak temperatures in comparison to the U-type piston bowl. The results also pointed out that changing the piston bowl type has negligible effects on the engine-out soot and CO2 emission characteristics of the engine. Based on this study, it is highly recommended to utilize the re-entrant piston bowl for four-stroke DI diesel engines to improve both engine performance and fuel oil consumption while reducing NO emission simultaneously.

Comparative Study of Ship Resistance and Fuel Consumption between Axe Bow and Moor Deep Ram Bow using CFD Method

Using a bulbous bow on the ship is the most common alternative way used to reduce resistance and fuel consumption. Some developments are created in terms of bow shapes to obtain the minimum shipping cost. The purpose of this study is to compare the total resistance (Rt) and specific fuel oil consumption (SFOC) in an 8000 DWT oil tanker by modifying the existing moor deep ram bow to axe bow using computational fluid dynamics (CFD) and empirical Holtrop method. Based on the results, the total resistance with a moor deep ram bow design at a service speed of 12 knots is 230,8 kN, while axe bow is 221,5 kN. This is directly proportional to the fuel consumption where by using axe bow, the ship will consume 83.64 tons in a trip of 1912 nautical miles. In contrast, with existing moor deep ram bow, the fuel consumption is just a slight 0.1 % higher than axe bow and still showing a competitive performance as it is generally used in cargo vessel.

The influence of SCR on main engine parameters

Air pollution from ships is increasing due to higher global demand of goods, and with them, global emission standards as well. These standards are prescribed by MARPOL Annex VI and the introduction of emission control areas (ECA). Ships built before 1990. do not have to comply with these rules, but ships built after the early 2000. must follow “NOx Emission Tier I”, which allows 17g/kWh NOx (for the slow speed diesel engines with <130 rpm), and selective catalytic reactors (SCR) are not necessary. Tier III NOx Emission standard was enforced in 2016 and it requires an 80% reduction in NOx emission compared to the Tier I, specifically 3.4 g/kWh, which can not be achieved without SCR or without using some other types of fuels. The focus of this paper is to do analysis how the ammonia dosage to SCR affects to the NOx formation in exhaust gasses on various engine speed (loads), as well as how it affects to some important engine parameters and specific fuel oil consumption (SFOC). The analysis was performed on Kongsberg engine room simulator (ERS), MC 90-V Model, as well as on MATLAB by using mathematical models. All external influences are excluded from the analysis like wind or rough sea. All data on different scenarios has been recorded after prolonged period to avoid inconsistencies. The results are shown graphically, and conclusions are presented.

Analysis of The Injection Pressure Effect on Single Cylinder Diesel Engine Power with Diesel Fuel-Methanol Blend

The use of fossil diesel fuels still produces carbon dioxide emissions (CO 2 ), sulphur dioxide (SO 2 ), hydrocarbon emissions (HC), nitrogen oxide (NO x ), and high total particles and carbon monoxide (CO). Moreover, the need for transportation of motor vehicles will always increase every year. The emission of exhaust gases resulting from the combustion process can essentially be reduced by improving fuel quality, the homogeneity of the fuel mixture, and regulating proper combustion. There are several ways to reduce exhaust emissions from diesel engines by providing precise injection pressures. This is done to get the perfect combustion. In addition, improving fuel quality is a way to reduce emissions of exhaust gases. Another one is by adding methanol to the diesel. The addition of methanol can reduce the emission of exhaust gas produced. The process of mixing the solar and methanol takes the addition of surfactants to obtain good homogeneity. Testing was conducted using simulation software with engine modeling. The result can be seen in the reduction and the addition of standard pressure 200 bar, that the emulsion fuel in SFOC (specific fuel oil consumption) suffered a decrease and increased by 0.2% and 0.3% at pressure 160 bar and pressure 240 bar. The fuel solution on SFOC suffered a decrease and an increase of 0.3% and 0.25% was produced by pressure 160 bar and pressure 240 bar. The highest NO x is produced by 240 bar injection pressures with Dexlite fuel while the lowest NO x is produced by 160 bar injection pressure with emulsion fuel.

바이오연료를 사용하는 소형어선 디젤발전기의 분사시기 변화가 연소특성에 미치는 영향

Recently, vegetable oil biofuels have become a part of everyday life in modern society. Biofuels play a role in reducing carbon emissions as well as natural living environments. In addition, there is an advantage in reducing exhaust gas emissions if biofuel energy is efficiently used. We intend to utilize the necessary technology using biofuels until achieving the alternative world’s future energy. 10%, 20% and 30% of biofuels were applied to the existing small fishing ship generators, and conditions the of optimal combustion were studied to control the timing of fuel injection appropriately. In the study, the test conditions were loaded at 0% to 100% at 1800rpm before TDC 18°, before TDC 22° and before TDC 28° from fuel injection timing in the small fish diesel generator engine. This study showed that cylinder pressure, rate of pressure rise and rate of heat release were increased in case of advancing fuel injection timing. Specific fuel oil consumption is indicated the least value at before TDC 28° of fuel injection timing.

Analysis of Performance, Emission, Noise and Vibration on Single Cylinder Diesel Engine After Installing Dual Fuel Converter-Kit Based on ECU

Now the demand for fuel oil has increased, this can cause fuel oil reserves to be depleted. To reduce the use of fuel oil, alternative energy is needed. One alternative energy that can be used to reduce fuel oil consumption is LPG (Liquid Petroleum Gas). The use of alternative fuels for LPG in diesel engines is done by converting diesel engines into dual fuel. This research aims to determine the effect of using dual fuel that are LPG-Diesel fuel on engine performance including power, torque, fuel consumption, emissions, vibration and noise. The research was conducted using a Yanmar TF 85 MH engine at 2000 RPM engine speed with variations in loading of 1000, 1500, 2000, 2500, and 3000 watts, and dual fuel with variations in injector openings of 3ms, 4ms, 5ms. Based on the research results, the use of LPG in dual fuel system with installing ECU (Electronic Control Unit) converter-kit, can replace diesel fuel oil consumption up to 93%. In the use of dual fuel there is an average decrease in power and torque of up to 1.95% if using only diesel fuel have average power up to 2.32 kW and torque up to 11.09 Nm. When using dual fuel there is a decrease in specific fuel oil consumption by up to 44% when using only diesel fuel have average fuel oil consumption up to 414.15 g/kWh. The maximum NOx emission produced is 1.83 g/kWh for a 3ms gas injector opening, 1.48 g/kWh for a 4ms gas injector opening, and 1.81 g/kWh for a 5ms injector opening. The maximum vibration generated is 33.2 m/s² for a 3ms injector opening, 31.4 m/s² for a 4ms injector opening, 27.46 m/s² for a 5ms injector opening, and when used only Diesel Fuel is 32.8 m/s2. The maximum noise generated is 92.33 dBA for 3ms injector opening, 92.43 dBA for 4ms injector aperture, 93.20 dBa for 5ms injector aperture, and 91.73 dBa when using diesel oil only.

A numerical study on the effects of charge air temperature on the combustion and emission characteristics of a marine generator engine

A numerical study was carried out to investigate the effectiveness of the charge air cooling method on the exhaust gas emission reduction when applied to a four-stroke marine generator diesel engine at full load. The AVL FIRE 2018a software was used to perform three-dimension (3D) simulations of the combustion process and emission formations inside the engine cylinder operating with various charge air temperatures (CATs). The simulation results were then verified by measured values obtained from experiments in the Green Ship Technology laboratory (GSTLab), Korea. The simulation results showed In-Cylinder peak pressure increase tendencies as the CAT decreased from 360 K to 320 K, leading to an increase in the brake mean effective pressure (BMEP) by 10.74%. At the same time, the In-Cylinder peak temperature was decreased, resulting in a reduction in NO emission by 33.85%. Soot, CO, and CO2 emissions were also reduced by 63.92, 44.66, and 3.22%, respectively. In addition, the CAT cooling method also reduced specific fuel oil consumption (SFOC) by 9.68% due to the increase in the indicated efficiency. This study would be a useful material for operating engines in cases of trying to reduce exhaust gas emissions from existing engines without any additional emission post-treatment device.

디젤기관의 Soybean-Oil 혼합율 및 연료 분사시기 변화가 배기배출물특성에 미치는 실험적 연구

In recent years, the issue of energy in the world is the part of most interest, and it is also a problem that is linked to the economic growth of each country. It has been reported to several scholars that the environmental problems of the earth are caused by the abnormal climate change all over the world. Such disasters of climate change frequently occur outside of the predictable range as the cause of the global ecosystem change. This study investigates the effect of the rate of biofuel mixing and the exhaust emissions characteristics caused by changing the fuel injection timing in diesel engines. As a result of experimets in test engines, specific fuel oil consumption is slightly increased in case of increasing biodiesel fuel ration and the NOx was also slightly increased. The specific fuel oil consumption is slightly decreased with leading fuel injection timing, but the NOx was increased.

APPLYING OF FUEL ADDITIVES IN MARINE DIESEL ENGINES

A method for improving the operational characteristics of a marine diesel engine by applying fuel additives has been proposed. A marine medium-speed four-stroke cycle diesel 6L20 by Wartsila-Sulzer was used for this research. 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 – decrease by 1.4 … 4.3 % in the concentration of nitrogen oxides in exhaust gases, was also found. It was shown that the concentration of the additive has an optimal value, can be determined experimentally and depends on the characteristics of the fuel and the load on the diesel engine.

Hydraulic System of Fuel Oil Supply to the Electronically Controlled Main Engine

Hydraulic system of the fuel oil supply to the electronically controlled main engine resolve the problem of the optimized control of the engine which act beneficially to the specific fuel oil consumption and a reduction of the NOx emission. The assumed numerical example is giving insight to the power consumption for the hydraulic control of the fuel oil injection and exhaust valve operation for the two stroke marine engine. The calculated power is higher for the fuel oil pressure booster operation compared to the exhaust valve actuator for about 88%, which is resulted due to the higher operating pressure of the fuel injection to the cylinder, versus lower operating pressure required for the opening of the exhaust valve.

A comparative methodological approach for the calculation of ships air emissions and fuel-energy consumption in two major Greek ports

ABSTRACT The scope of the paper is to focus on the main technical discrepancies, that is, engine load factor (LF), specific fuel oil consumption (SFOC), emissions factors (EF), included in the existing methodological approaches for calculating ships’ on-board emissions and propose a framework that will allow various stakeholders to conduct accurate air emissions calculations based on publically available operational data. A bottom-up methodology has been employed for the calculation of fuel-energy consumption and air emissions (CO2, SOx, NOx, PM10) in two major ports (Souda and Heraklion) of Crete island in Greece for passenger ferries and cruise ships for the years 2018 and 2019 and for both main and auxiliary engines of all vessels. Due to the lack of publically available technical data, the proposed methodology is based on the estimation of SFOC values through a regression analysis that leads to accurate and reliable results. The basic scenario is based on a detailed estimation of SFOC via a regression analysis applied on engine’s technical data, while the alternative approaches employ SFOC estimated through the application of specific adjustment factors and main engine power based on ship’s gross tonnage. The basic scenario results are the most accurate data while in most other cases air emissions are underestimated observing significant differences between the different methodologies.

Utjecaj prostora presjeka turbo mlaznice na rad pomorskoga dizelskog stroja

After a long period of use, some important technical parameters of the main marine diesel engines (MDE) gradually become worse, such as the turbine speed, intake pressure, exhaust temperature, engine power, and specific fuel oil consumption (SFOC). This paper studies the affections of the turbine nozzle cross-sectional area (AT) to MDE and presents a method of AT adjustment to improve the performances of MDE. A mathematical model of an engine was built based on the existent engine construction and the theory of the diesel engine working cycle and the simulation was programmed by Matlab/Simulink. This simulation model accuracy was evaluated through the comparison of simulation results and experimental data of the MDE. The accuracy testing results were acceptable (within 5%). The influences of AT on the engine working parameters and the finding optimization point were conducted by using the simulation program to study. The predicted optimization point of the nozzle was used to improve the engine’s performances on board. The integration of the simulation and experiment studies showed its effectiveness in the practical application of the marine diesel engine field.

Numerical investigation of the high pressure selective catalytic reduction system impact on marine two-stroke diesel engines

This study aims to investigate the impact of the High Pressure Selective Catalytic Reduction system (SCR-HP) on a large marine two-stroke engine performance parameters by employing thermodynamic modelling. A coupled model of the zero-dimensional type is extended to incorporate the modelling of the SCR-HP components and the Control Bypass Valve (CBV) block. This model is employed to simulate several scenarios representing the engine operation at both healthy and degraded conditions considering the compressor fouling and the SCR reactor clogging. The derived results are analysed to quantify the impact of the SCR-HP on the investigated engine performance. The SCR system pressure drop and the cylinder bypass valve flow cause an increase of the engine Specific Fuel Oil Consumption (SFOC) in the range 0.3–2.77 g/kWh. The thermal inertia of the SCR-HP is mainly attributed to the SCR reactor, which causes a delayed turbocharger response. These effects are more pronounced at low engine loads. This study supports the better understanding of the operating characteristics of marine two-stroke diesel engines equipped with the SCR-HP and quantification of the impact of the components degradation on the engine performance.

Modeling, Control and Power Management of Six-Phase PMSM Based Shipboard MVDC Distribution System

In the modern shipboard power system, there is a growing concern about reduced fuel economy, efficiency improvement, and minimized emission in recent years. Besides, considering the islanded nature of the shipboard power system, ensuring the system reliability at both generation and load side is crucial. In this context, a hybrid medium voltage DC (MVDC) distribution system concept with diesel engine, PV system, and battery energy storage system (BESS) as the generators for the shipboard power system is proposed. Variable speed operation of a diesel engine is considered for the benefit of minimal specific fuel oil consumption (SFOC). Regarding the fault-tolerant characteristics of six-phase permanent magnet synchronous machine (PMSM), it is used for both generating and motoring application, thus maintaining system reliability at any time. A hierarchical control system is designed and implemented to ensure proper load power-sharing among the generators and to regulate the dc-link voltage of the proposed MVDC distribution system. To bolster the intent of minimal SFOC zone operation of diesel engines and coordination between the generators and load, a deterministic rule-based power management system is proposed and implemented. The simulation is carried out for potential operational modes of a cruise ship in the MATLAB/Simulink environment. Simulation results show that the proposed topological and control structure has satisfactory performance in terms of power delivery, stable dc-link dynamics, and overall system stability.

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.