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Propulsion in waves is a complex physical process that involves interactions between a hull, a propeller, a shaft and a prime mover which is often a diesel engine. Among the relevant components, the diesel engine plays an important role in the overall system dynamics. Therefore, using a proper model for the diesel engine is essential to achieve the...
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... 5.30 15.9 (F max < 0.67). No oscillation is observed in this case, but it was present after the step is applied in some cases of low J prop and high K p . The correlation coefficients between the parameters and the output results are shown in Fig. 20 as a correlation matrix. In terms of the speed response, the mass moment of inertia of the turbocharger rotor has the highest influence whereas the mass moment of inertia of the propulsion system has a negligible correlation. The dominant influence of the turbocharger can be explained by the turbo-lag where the fuel injection is ...
Citations
... Finally, the governor, connected to the engine model, regulates and controls the engine's speed and power output to ensure efficient operation and stability of the propulsion system. Together, these components form a comprehensive block diagram that orchestrates the functioning of an underwater vehicle's propulsion system [108]. 2) Navigation control system ...
Autonomous Underwater Vehicles (AUVs) epitomize a revolutionary stride in underwater exploration, seamlessly assuming tasks once exclusive to manned vehicles. Their collaborative prowess within joint missions has inaugurated a new epoch of intricate applications in underwater domains. This study’s primary aim is to scrutinize recent technological advancements in AUVs and their role in navigating the complexities of underwater environments. Through a meticulous review of literature and empirical studies, this review synthesizes recent technological strides, spotlighting developments in biomimicry models, cutting-edge control systems, adaptive navigation algorithms, and pivotal sensor arrays crucial for exploring and mapping the ocean floor. The article meticulously delineates the profound impact of AUVs on underwater robotics, offering a comprehensive panorama of advancements and illustrating their far-reaching implications for underwater exploration and mapping. This review furnishes a holistic comprehension of the current landscape of AUV technology. This condensed overview furnishes a swift comparative analysis, aiding in discerning the focal points of each study while spotlighting gaps and intersections within the existing body of knowledge. It efficiently steers researchers toward complementary sources, enabling a focused examination and judicious allocation of time to the most pertinent studies. Furthermore, it functions as a blueprint for comprehensive studies within the AUV domain, pinpointing areas where amalgamating multiple sources would yield a more comprehensive understanding. By elucidating the purpose, employing a robust methodology, and anticipating comprehensive results, this study endeavors to serve as a cornerstone resource that not only encapsulates recent technological strides but also provides actionable insights and directions for advancing the field of underwater robotics.
... CFD can be used to simulate the propeller performance and cavitation at full scale (Aktas et al., 2016;Kim et al., 2021a) and estimate the propeller performance influenced by the roughness (Owen et al., 2018;Sezen et al., 2021aSezen et al., , 2021b, which has a significant effect on propeller performance in terms of torque, efficiency and cavitation. The variation of wake fraction along the propeller disk is also computed in calm water (Taskar et al., 2016), manoeuvring (Broglia et al., 2013;Dubbioso et al., 2021), and in the presence of waves (Polyzos and Tzabiras, 2020;Yum et al., 2017). ...
This paper presents a comprehensive review of the current regulations and the various technologies as well as the decision support methods for each technology the maritime industry considers to ensure the fleet's sustainability. It covers the period between 2010 and 2022, emphasizing the last four years. It shows the impact of each technology on the reduction of ship resistance and the energy required on board, affecting the amount of fuel consumption and avoiding the transportation of harmful species around the world to achieve a smooth transition towards green shipping by improving the fleet's energy efficiency and achieving the goals of the 2050 plan. The paper covers five main topics: hull design, propulsion systems, new clean fuels and treatment systems, power systems and ship operation; and each topic has different technologies included. This study's findings contribute to mapping the scientific knowledge of each technology in the maritime field, identifying relevant topic areas, visualising the links between the topics, and recognising research gaps and opportunities. This review helps to present holistic approaches in future research supporting the cooperation between maritime industry stake-holders to provide more realistic solutions toward sustainability.
... If two of the specific parameters are known, the other two can be interpolated according to the database extracted from the state map. Since the parameters of the performance map are given in corrected values, it is necessary to perform a conversion between the corrected and the real values [54]. The power consumption and outlet temperature are derived by using the compressor pressure ratio and efficiency [55]. ...
Most large commercial vessels are propelled by low-speed two-stroke diesel engines due to their fuel economy and reliability. With increasing international concern about emissions and the rise in oil prices, improvements in engine efficiency are urgently needed. In the present work, a zero-dimensional model for a low-speed two-stroke diesel engine is developed that considers the exhaust gas bypass and geometry structures for the gas exchange model. The model was applied to a low-speed two-stroke 7G80 ME-C9 marine diesel engine and validated with engine shop test data, which consisted of the main engine performance parameters and cylinder pressure diagrams at different loads. The simulation results were in good agreement with the experimental data. Thus, the model has the ability to predict engine performance with good accuracy. After model validation, the variations in compression ratio, fuel injection timing, exhaust gas bypass valve opening portion, exhaust valve opening timing, and exhaust valve closing timing effects on engine performance were tested. Finally, the influence level of different parameters on engine performance was summarized, which can be used as a reference to determine the reasons for high fuel consumption in some cases. The developed engine performance model is considerable in digital twins for performance simulation, health management, and optimization.
... It is reasonable to think that the engine control strategy has an impact on the overall propulsion efficiency. 3 A parallel can be drawn with passenger cars where a constant speed controller may not be the strategy minimizing fuel consumption. 4 Therefore, this paper numerically investigates alternative engine control options. ...
... Investigations by Taskar et al. 15,16 and Yum et al. 3 have shown that unsteady propeller inflow can cause significant increase in power and fuel consumption to keep the ship speed constant. ...
According to the International Maritime Organization (IMO)’s Greenhouse Gas (GHG) strategy whose aim is to reduce the shipping industry’s total carbon emissions by 50% by the year 2050, it is desirable to increase ships energy efficiency to reduce GHG emissions and fuel costs. To do so, a short-term measure is to develop innovative engine control strategies in waves that will reduce ship’s GHG emissions. In this study, a mathematical model is developed to assess two engine control strategies: the standard constant rotational speed mode and an innovative constant fuel rack approach. The coupled model is made of a mean value engine, propeller curves and a ship behavior simulator. Emphasis is placed on the presentation of the engine model and references are given for further details on the ship simulator. After verifying the coupling between the engine model and the ship simulator, the fuel consumption is compared, for the two strategies, at the same average speed and for three head regular waves. This paper presents the basics of a further long time research project and shows that coupling ship simulators with engine simulators leads to promising simulation tools for a ship’s GHG emissions reduction. Results from a first application case show that the constant fuel rack approach reduces fuel consumption (up to 1.6%).
... In (Taskar et al., 2016), the effects of propeller wake variation and emergence on the engine-propeller dynamics and ship propulsion performance when sailing in waves have been investigated. In (Yum et al., 2017), the simulation of a two-stroke marine diesel engine for ship propulsion in waves has been conducted based on a propulsion system model in waves; and the effects of propeller inflow velocity variations and propeller emergence on the transient performance of the engine have been investigated. A detailed crank-angle engine model has been used in (Taskar et al., 2016) and (Yum et al., 2017) to investigate the wave effects on the engine dynamics, however, only ship propulsion in waves has been considered, while ship manoeuvring in wind and waves when sailing in adverse sea has not been taken into account. ...
... In (Yum et al., 2017), the simulation of a two-stroke marine diesel engine for ship propulsion in waves has been conducted based on a propulsion system model in waves; and the effects of propeller inflow velocity variations and propeller emergence on the transient performance of the engine have been investigated. A detailed crank-angle engine model has been used in (Taskar et al., 2016) and (Yum et al., 2017) to investigate the wave effects on the engine dynamics, however, only ship propulsion in waves has been considered, while ship manoeuvring in wind and waves when sailing in adverse sea has not been taken into account. In (Aung and Umeda, 2020), based on the simulation model for ship manoeuvring in adverse weather conditions, the effects of different sea states (indicated by Beaufort No.), ship initial forward speed and engine SMCR power on ship manoeuvring behaviour in adverse weather conditions have been investigated; the influence of the emergence of propeller and rudder has been considered. ...
Current EEDI (Energy Efficiency Design Index) regulations striving to reduce the installed engine power on new ships for a low EEDI may lead to underpowered ships having insufficient power when operating in adverse sea conditions. In this paper, the operational safety of a low-powered ocean-going cargo ship operating in adverse sea conditions has been investigated using an integrated ship propulsion, manoeuvring and sea state model. The ship propulsion and manoeuvring performance, especially the dynamic engine behaviour, when the ship is sailing in heavy weather and turning into head sea, have been studied. According to the results, the dynamic engine behaviour should be considered when assessing the ship operational safety, as the static engine operating envelope is inadequate for the safety assessment. The impact of PTO/PTI (power-take-off/in) operation and changing propeller pitch on the ship thrust availability in adverse sea conditions have also been investigated. To protect the engine from mechanical and thermal overloading, compressor surge and over-speeding during dynamic ship operations and/or in high sea states, the engine and propeller should be carefully controlled. The paper shows that if in (heavy) adverse weather the propeller pitch can be reduced or if the shaft generator can work as a motor (PTI), more thrust can be developed which can significantly improve the operational safety of the ship.
... More studies have been published to estimate the ship, propeller and engine performance in a faster way than using CFD. These studies can estimate the whole performance of the vessel using empirical formulas and in an instantaneous way (Yum et al., 2017) to give a better understanding of these complex physical processes. A ship routing is an extension of this subject to select the route according to the defined objective (Prpić-Oršić et al., 2016, Zaccone et al., 2018, Granado et al., 2021. ...
In this paper, the estimation of ship fuel consumption is computed for different weather condi-tions along the ship route. The propeller is first optimized for calm water conditions using a previous devel-oped optimization model coupling NavCad software and a nonlinear optimizer integrated in Matlab. Then, thepropeller performance and ship speed reduction are computed based on the added resistance corresponding toweather conditions expectable along the route. The Aertssen method is used to compute the ship added resist-ance based on significant wave height and wave period. Three ship speed reduction strategies are proposed inthis study when the ship speed exceeds the engine limits, therefore the ship speed is corrected at: (1) 90%, (2)70% and (3) 50% of the engine rated power. Then, a weighted average fuel consumption along the ship routewith different weather conditions is computed for each case. It has been found that the expectable reduction infuel consumption is of 2.6% and 1.7% in cases (2) and (3) respectively, when compared to the first case.
... Therefore, appropriate control is required. In work [12], the authors highlight the issue of optimal control of a marine diesel engine, supplementing its work with an analysis as part of the hydrodynamic complex "hull-propeller shaft-diesel engine". But the issue of managing the complex when weather conditions change, contributing to the appearance of regular and irregular waves in the marine environment, has not been considered. ...
... where Ф 0 =φ 0 /φ min. Taking into account expressions (12), equations (9) will take the form: ...
The high pressure fuel system is the fundamental system that forms the indicator of the minimum fuel consumption per unit of the vessel's path.
The calculation of the optimal control of the vessel complex with the main diesel engine is performed according to the criterion of the minimum fuel consumption per unit path at a given average velocity of the vessel.
The propulsion of a vessel with a main diesel engine is described by equations. The equations contain a significant number of parameters, the reduction of which is performed by introducing dimensionless quantities, followed by bringing the equations into dimensionless forms. This made it possible to present a solution to the optimal control law for the main vessel diesel engine as part of the vessel complex.
Optimal control of the vessel complex under stormy navigation conditions has been investigated. The calculations of the control law of the vessel complex, which ensure the movement of the vessel with the maximum average velocity in conditions of stormy navigation, are presented. It is determined that the established law of control of the vessel complex ensures the minimum fuel consumption per mile at a given average velocity of its movement. The influence of a high-pressure fuel system on the optimal control of a vessel diesel engine has been investigated.
Thus, the calculated studies indicate that for all values of the parameters of the vessel complex according to the law of control of the fuel system Ф=а+b∙C2(τ), they give fuel savings up to 6% per unit of way in comparison with the law of control of the vessel complex Ф=а+b∙(c1(τ)/c2(τ)).
The obtained ratios during modeling and optimal control of the main diesel engine of the vessel complex allow using the dynamic programming method to analyze the fuel consumption per unit path with optimal control compared to the corresponding constant control
... The auxiliary blower is located in parallel with the non-return valve between the charged air cooler and the inlet receiver. The blower will assist the air supply when the turbocharger is not capable of delivering sufficient air at low engine loads (Yum et al., 2017). During engine operations, when the scavenging pressure drops below a pre-set pressure (corresponding to an engine load of approximately 25e35%) the blower will start and continue to run until the scavenging pressure exceeds a certain value higher than the pre-set pressure (corresponding to an engine load of approximately 30e40%) resulting in an appropriate hysteresis (MAN, 2014b). ...
Analysis
of ship propulsion system performance is often performed using detailed hydrodynamic models to assess load changes, which are subsequently compared to static engine limits, or by detailed engine models that are rarely integrated with sufficiently detailed propulsion models for load change estimation. To investigate the dynamic engine (overloading) behaviour and ship propulsion performance under various heavy operating conditions, a mean value first principle parametric (MVFPP) engine model is integrated into a ship propulsion system model in this paper. An upgraded thermodynamic-based MVFPP model for two-stroke marine diesel engines is presented, in particular a newly developed MVFPP gas exchange model. Based on the integrated propulsion system model of a benchmark ocean-going chemical tanker, the engine dynamic behaviour during ship acceleration, deceleration and crash stop has been investigated. Results show that, during dynamic processes, the engine could be thermally overloaded even if the engine power trajectory is inside the static engine operating envelope. The paper contributes to finding proper indicators for thermal overloading of modern two-stroke marine diesel engines. It is demonstrated that when matching the engine with the propeller and designing the ship propulsion control system, not only the static engine operating envelope, but also the dynamic engine behaviour should be considered.
... It is very important to have a detail knowledge of the engine performance, as the prime part of the ship's propulsion system. Among the various models such as transfer function models [14], zero or one-dimensional models [15], and multi-zone phenomenological models [16] and cycle Mean Value Engine Models (MVEMs) [12,[17][18][19] capable of evaluating the engine performance, the mean value engine model (MVEM) has least complexity, much less input data requirements and an adequate calculation execution time. In a transfer function model, which usually represents the relationship of fuel consumption to engine speed, the essential characteristics of the system does not reflect. ...
The behavior of ship engine encountering stormy waters with different sea wavelengths has been investigated. In this study, a mathematical model is developed using governing equations for various parts of the ship, that is the hull, engine, power transmission shafts from the engine to the propeller also the propeller of the ship itself were implemented in MATLAB/ Simulink software environment. The model consists of the torsional vibrations of the transmission shafts; this enables a more accurate analysis of the engine behavior which is the source of power generation in the ship's propulsion system. The simulation results showed that the wavelength of sea waves has a significant effect on the dynamic performance of the engine. In this research, the effect of different ratios of wavelength to ship length (λ/LPP) including 0.5, 1, 1.5 and 2 in violent stormy sea conditions with a wave height of 11.5 m and wind speed of 28.5 m/s has been investigated. The results showed that with the exception of λ/LPP of 1.5, at another ratios of λ/LPP, changes in engine performance parameters such as torque, fuel and air consumption, CO2 emission and power are decreasing with increasing wavelength. Most variations in engine speed are related to λ/LPP of 2. The results showed that by reducing the wavelength, the period of oscillations is reduced. As the ratio of wavelength to ship length increases, the number of oscillating points in the engine behavior increases and the lowest number of oscillating points can be seen at λ/LPP of 1.5. This study highlights the importance of effects of sea wavelengths as one of the most important physical parameters of the sea which should not be ignored in the design phase of the ship propulsion system and engine selection. © 2021 Materials and Energy Research Center. All rights reserved.
... In (Taskar et al., 2016), the effects of propeller wake variation and emergence on the engine-propeller dynamics and ship propulsion performance when sailing in waves have been investigated. In (Yum et al., 2017), the simulation of a two-stroke marine diesel engine for ship propulsion in waves has been conducted based on a propulsion system model in waves; and the effects of propeller inflow velocity variations and propeller emergence on the transient performance of the engine have been investigated. A detailed crank-angle engine model has been used in (Taskar et al., 2016) and (Yum et al., 2017) to investigated the waves effects on the engine dynamics, however, only ship propulsion in waves has been considered, while ship manoeuvring in wind and waves (such as turning into head waves) in adverse sea conditions has not been taken into account. ...
... In (Yum et al., 2017), the simulation of a two-stroke marine diesel engine for ship propulsion in waves has been conducted based on a propulsion system model in waves; and the effects of propeller inflow velocity variations and propeller emergence on the transient performance of the engine have been investigated. A detailed crank-angle engine model has been used in (Taskar et al., 2016) and (Yum et al., 2017) to investigated the waves effects on the engine dynamics, however, only ship propulsion in waves has been considered, while ship manoeuvring in wind and waves (such as turning into head waves) in adverse sea conditions has not been taken into account. In (Aung and Umeda, 2020), based on the simulation model for ship manoeuvring in adverse weather conditions, the effects of different sea states (indicated by Beaufort No.), ship initial forward speed and engine SMCR power on ship manoeuvring behaviour in adverse weather conditions have been investigated; the influence of the emergence of propeller and rudder has been considered. ...
... The auxiliary blower is located in parallel with the non-return valve between the charged air cooler and the inlet receiver. The blower will assist the air supply when the turbocharger is not capable of delivering sufficient air at low engine loads (Yum et al., 2017). During engine operations, when the scavenging pressure drops below a pre-set pressure (corresponding to an engine load of approximately 25-35%) the blower will start and continue to run until the scavenging pressure exceeds a certain value higher than the pre-set pressure (corresponding to an engine load of approximately 30-40%) resulting in an appropriate hysteresis (MAN, 2014). ...
The shipping industry, which remains the backbone of international merchandise trade, is striving to reduce its operational cost and more importantly its environment impact. New ships need meet the EEDI (Energy Efficiency Design Index) requirements of IMO (International Maritime Organization). However, the current EEDI is not able to accurately evaluate the real lifetime carbon emissions of the ship. Under the guidance of current EEDI regulation, the ship designers, owners and policymakers could be misled to adopt the configurations that are underperforming or even leading to an increase of CO2 emissions in reality. A technically easy and effective solution to meet the EEDI requirement is to lower the installed engine power and thus the ship design speed. However, reducing the installed engine power could lead to an underpowered ship, which could have insufficient power for propulsion and steering in adverse weather conditions. The main research question addressed in this dissertation is: What is the transport performance of ocean-going cargo ships with small EEDI when sailing in realistic operating conditions; are these ships safe when sailing in heavy operating conditions; and, how to improve both the transport performance and operational safety of ocean-going cargo ships by using the short-term applicable ship propulsion options? The ship transport performance investigated in this dissertation includes the energy conversion performance, fuel consumption performance and emissions performance. The influences of the operational ship speed reduction, propulsion control, PTO (power-take-off)/PTI (power-take-in), and using LNG (liquefied natural gas) as the fuel as well as the combination of these measures on the ship transport performance have been systematically investigated. The operational safety investigated in this dissertation includes both engine operational safety and ship operational safety. The engine dynamic behaviour during ship acceleration, deceleration, crash stop, and turning in normal sea condition have been investigated. The ship propulsion and manoeuvring performance when sailing in head sea, accelerating in head sea and turning to head sea in adverse sea conditions have been investigated. The influences of propeller pitch and PTO/PTI on the ship thrust limit and engine behaviour have also been investigated. As a reflection of the research in this dissertation, suggestions on amendments of IMO’s current EEDI has been provided. The proposal for amending the current EEDI formula tries to make the EEDI calculation more realistic and representative when evaluating ship transport performance at the design stage. Moreover, it can also partly solve the other weakness of the current EEDI with respect to the issues of underpowered ships.
