Main Propulsion Research Articles

Exploring Differing Perspectives on Sustainability and Corresponding Strategies in German Automotive Companies

In addition to acute crises dominating the societal discourse, such as the global consequences of the COVID-19 pandemic and the Russian invasion of Ukraine, the world continues to face the ongoing challenge of limiting climate change and achieving a sustainable transformation. Yet, in public discourse, the widely used terms “sustainability” and “transformation” are not clearly defined, and the understanding varies greatly depending on the industry and the stakeholders considered. One important transformation arena lies within the German automotive industry, as it is one of the country’s biggest industrial sectors by revenue and the number of employees. In addition, the German automotive industry is currently going through a transition period due to the switch to electric drivetrains as the main propulsion technology opposed to combustion engines. Therefore, the following paper identifies the differing understandings of sustainability and according actions in the German automotive industry. Moreover, possible conflicts and prioritizations along the economic, ecological, and social dimensions of sustainability are presented based on an expert interview study. To do so, a structuring qualitative content analysis in combination with a descriptive approach was used focusing on the differing perspectives on sustainability of both the interviewees and their companies. The gathered data then allows to compare the aggregated individual and corporate sustainability perspectives in the German automotive industry, as well as comparing the sustainability perspectives of the interviewees and their respective companies case by case. The results suggest that there is a considerable discrepancy between individual and corporate understandings of sustainability. These differences can mainly be attributed to the companies’ economically driven views in contrast to the individuals’, mostly ecologically driven sustainability perspective. Moreover, several barriers and conflicts, rooted in the prioritization of economic gains, can be traced back to conflicts in the supplier pyramid. The identification of common transformation goals and measures among companies is necessary to enable a collaborative, sustainable transformation in the German automotive industry, which benefits all societal stakeholders in or attached to this sector.

Methods of reducing fuel consumption by seagoing vessels in order to reduce emissions of harmful substances into the atmosphere

The aim of the paper is to draw attention to the emissions of toxic compounds into the atmosphere problem by seagoing ships. Annex VI of the MARPOL Convention, which came into force in 2005, concern the prevention of air pollution from ships, forced shipowners to use solutions aimed at limiting the emission of these harmful substances into the atmosphere. One of the instruments enabling the implementation of these guidelines is the design energy efficiency index EEDI, introduced obligatorily for designed and newly built ships. In turn from 2013, the regulations also oblige shipowners to maintain an effective energy management plan during ship's operation, SEEMP (Ship Energy Efficiency Management Plan). The paper presents factors that influence the reduction of fuel consumption by ships, leading to a reduction in emissions of harmful substances into the atmosphere and thus achieving the required EEDI and other indicators. These are factors related to the ship's hull, the main propulsion engine and the propeller-rudder system. The influence of each of these factors on the level of fuel consumption by the ship was indicated. The work highlights the methods of reducing fuel consumption by seagoing ships aimed at reducing emissions of toxic compounds into the atmosphere, which are currently the most popular and effective, and relate mainly to the hull and main propulsion engines.

Failure of the Emergency Generator Start-Stop Working System on the AHTS Logindo Sturdy Ship

An emergency generator is a backup generator that is used only for emergencies. When the ship operates normally, the generator is on stand-by or ready to be activated at any time. During an emergency, such as when the ship experiences damage that causes the main propulsion power source, auxiliary machinery, and other equipment to stop operating due to a lack of electricity supply from a failure in the electrical system, the emergency generator system is needed to replace the function of the ship's main generator. This research uses descriptive qualitative methods. The results of this research can be summarized as follows: 1) The implementation of work safety on ships is considered less than optimal; 2) The implementation of work safety significantly influences the mentality and quality of work; and 3) Supervision activities on board the ship are carried out through safety meetings.

Low-velocity impact localization on a full composite wing of UAV using fiber optic sensors under operating environments

In this paper, low-velocity impact localization algorithms were suggested using fiber optic sensing system. In order to obtain high frequency signals due to low-velocity impact, a commercial high speed fiber Bragg grating (FBG) sensing system (a sampling speed of 100 kHz) was adopted. The test article is a full-scale composite wing box structure as the main wing of an unmanned aerial vehicle. The multiplexed FBG sensor array was attached on the lower surface of the upper skin. Low-velocity impact experiments were performed to obtain the impact signals for the reference data set. The reference data set is composed of the impact signals from the impacts on the reference points. The suggested algorithm in this study is based on the comparisons between impact signals and the reference signals in the database set. The main idea is to determine the reference point which has the most similar data set as the impact location. This idea was validated from the experiments of the non-reference points. As the next step, operational environments were considered to enhance the reliability of the suggested algorithm. The considered environments are the static loads and vibrations. These days, most of UAVs use the electric motors and propellers as the main propulsion system. Thus, harsh vibrations inherently occur and affect the performance of impact localization algorithms. From the experiments under these operating environments, it can be checked that the suggested algorithm has sufficient robustness to such environments.

A Review of Research on Marine Main Propulsion Systems

Ship power, as an essential component of ship engineering, directly affects the navigation performance, economy, and environmental friendliness of ships. This article reviews the development history of ship power, introduces the main propulsion devices including internal combustion engines, steam engines, and electric motors, and discusses the structure and optimization design of ship power systems. Modern ship power technology includes traditional diesel and gasoline engines, as well as new power devices such as liquefied natural gas (LNG) engines, hybrid power systems, and fuel cells. Electric ships are gaining attention due to their efficiency and environmental benefits. In the future, ship power technology will develop towards green environmental protection, intelligence, integration, diversification, and digitization, providing more reliable and efficient power support for the shipping industry and the advancement of ship engineering.

Early-Stage ISC Fault Detection for Ship Lithium Batteries Based on Voltage Variance Analysis

With the progressive development of new energy technologies, high-power lithium batteries have been widely used in ship power systems due to their high-power density and low environmental pollution, and they have gradually become one of their main propulsion energy sources. However, the large-scale deployment of lithium batteries has also brought a series of safety problems to ship operations, especially the battery internal short circuit (ISC). Battery ISC faults are very hidden and unpredictable at the initial stage and often fail to be detected in time, ultimately leading to overheating, fire or even an explosion of the ship’s power system. Based on this, this paper proposes a fast and accurate method for early-stage ISC fault location and detection of lithium batteries. Initially, voltage variations across the lithium battery packs are quantified using curvilinear Manhattan distances to pinpoint faulty battery units. Subsequently, the localized characteristics of voltage variance among adjacent batteries are leveraged to detect an early-stage ISC fault. Simulation results indicate that the proposed method can quickly and accurately locate the position of 5 Ω, 10 Ω and 15 Ω ISC faulty batteries within the battery pack, as well as detect the abnormal batteries in a timely manner with considerable sensitivity and reliability.

Modeling and simulating axial vibrations on the crarkshaft of the large two-stroke marine diesel engine

The axial vibration is the strong vibrated phenomenon occurring on the main propulsion using a large two-stroke marine diesel engine. This article researches to build a mathematical model of the axial stiffness coefficient and force generated by the geometric configuration of the crank pin-crank web assemblies and the combustion gas force. The numerical simulation is performed by finite element method, using ANSYS software, applied to the main engine MAN B&W 6G70ME. Keywords: Axial stiffness; crank pin–crank web set; axial force; diesel crankshaft; large two-stroke marine diesel engine; Axial vibration simulation.

Studying influence of the mathematical model error on the results of calculating freedom torsional vibration for marine diesel propulsion system

The Freedom Torsional Vibrations (FTV) Calculation (FTVC) for the marine main propulsion plant (MPP) to determine the freedom frequencies and the FTV formations of the mechanical system. Normally, the MPP is dynamically modeled as a finite n concentrated masses with the parameters of: Mass moment of inertia Jk (kgm2, k = 1÷ n) and the torsional stiffness Ck,k+1 (Nm/rad) between the k and k+1 concentrated masses. This paper studies the influence of the number of concentrated masses n as well as the accuracy of determining Jp (Moment of inertia of the propeller) on the solution of the MPP's FTVC. The research verifies to the MMP on the Korean ship XXX-XXX-XXX, using the MDE 6G70MEC. Keywords: Freedom Torsional Vibration (FTV); Mathematic model of the FTV; Exactness of the FTV calculation.

Marine temperature and humidity regulation combined system: performance analysis and multi-objective optimization

The efficient and environmentally friendly air conditioning system plays a vital role in cost reduction and efficiency improvement within the shipping industry. This study focuses on a specific ocean-going container ship equipped with the 8S90ME-C10.2 marine diesel engine as its main propulsion system. Firstly, the cooling load of 149.56 kW and a wet load of 18.04 g/s for the container ship were calculated to determine an energy-efficient and comfortable air conditioning scheme. Secondly, a novel combined system, integrating temperature and humidity solution dehumidification with enhanced transcritical CO2 refrigeration using injection subcooling, was proposed. The regenerator for solution dehumidification and the generator for injection refrigeration utilized the main cylinder liner cooling water as a heat source. Based on the system modeling, numerical simulation, and result validation, comprehensive analyses and quantitative evaluations were conducted to investigate the sensitivity of temperature and humidity regulation parameters, system performance, components exergy efficiency, and economics. Finally, employing a multi-objective optimization algorithm, the optimal operating conditions and corresponding objective functions for the system were obtained: exhaust pressure of 9.43 MPa, regeneration temperature of 91.08 °C, subcooling degree of 19.48 °C, coefficient of refrigeration performance of 3.697, exergy loss of 84.136 kW, and an annual operating cost of $111,300. This combined system exhibits high efficiency, environmental friendliness, and comfort, making it well-suited to handle the fluctuating heat and humidity loads during the ocean-going container ship through varying sea climates.

A numerical simulation tool for a wind-assisted vessel verified with logged data at sea

This paper presents a comprehensive numerical simulation tool for a wind-assisted container ship that is used to evaluate vessel performance on real-world shipping routes. The model includes the dynamics of the ship hull, rudder and a controllable pitch propeller (CPP), as well as fuel consumption characteristics of the main propulsion diesel engine and the force profile generated by a pair of suction sails. The fidelity of this simulation tool is verified by on-board sensor measurements conducted during short sea trials and long-distance real-world vessel routes. Based on the verified model, performance prediction plots (PPP) for different modes of operation with wind assistance are utilized to assess energy efficiency and the potential for additional savings in an integrated wind-hybrid propulsion system. It is expected that this PPP methodology can be exploited for future optimization studies of either retrofit or new builds.

Analisis Penyebab Terjadinya Blackout pada KM. Dharma Kartika IX saat Bermanuver

A blackout on a ship is a condition where the main propulsion power source on the ship does not operate due to the lack of electrical supply from the diesel generator, which serves as the primary source of electricity on the ship. Ship maneuvering, on the other hand, refers to the ability to turn and pivot while sailing. This ability is crucial for the safety of the ship, especially when operating in restricted waters or near ports. The blackout occurs as a result of generator overload or the inability of an electrical voltage and current to flow too high or too large. The load is too high because the bow thruster consumes too much electrical voltage. In fact, on KM. Dharma Kartika IX, the generator has already supplied a significant amount of electricity to various parts of the ship, including the lighting system throughout the ship, from the mast to deck 3, the cooling system, and several navigation systems. The aim of this research is to understand and explain the causes of blackouts in the electrical system of KM Dharma Kartika IX during maneuvering and to find solutions that should be implemented in case of problems with the generator unit. The method I used to gather this data is through direct observation during seagoing service on the subjects under examination.

Investigating the Chemical Stability of Electrospray Plumes During Particle Collisions

Electrospray thrusters fulfill the main propulsion requirements for long-term small-satellite missions. However, the molecules present in the plume are susceptible to collisions, chemical reactions, and fragmentation, which may introduce different new species with various mass-to-charge ratios inside the plume. Prediction of the byproducts that appear upon collisions is of prime importance to predicting the evolution of the plume and estimating the performance and the lifetime expectancy of the thruster. In this work, we use molecular dynamics simulations to investigate monomer–neutral collisions at different impact configurations, impact energies, and impact parameters, and we provide the mass spectra of the resulting species. We predict that 1) collisions within a center-of-mass distance of 6 Å can result in momentum exchange and molecular fragmentation, 2) higher-energy impacts produce more byproducts, and 3) heavy molecules (e.g., 1-ethyl-3-methylimidazolium [EMI] and BF4) are more likely to result from weak collisions (<30 eV), whereas light molecules (e.g., H, F, and CH3) are more likely to result from strong collisions. Collisional fragmentation is shown to negatively affect key performance indicators, including reductions in thrust, specific impulse, and propulsive efficiency. This phenomenon potentially accounts for the observed discrepancies in experimental measurements of current and mass loss rates.

Simulation Experiment and Teaching Research of a Land-Based Ship Engine Room

In order to make up for the shortage of scientific research experiments and teaching in land-based engine room laboratory, a simulation system is designed and developed using B/S mode to simulate scientific research experiments, teaching and operation processes, and designed algorithms to simulate the propulsion characteristics of the main propulsion diesel engine. A large number of experiments were carried out, and the relationship curve between output power and fuel consumption rate of the main engine was obtained in the laboratory. Apache JMeter was used to test the pressure of the simulation system deployed in Dalian Maritime University Cloud. It is found that under the test conditions, the average response time of sample request is 330 ms, which is far superior the design standard of 2 s. There is no abnormal response to all requests, and all indicators fully meet the requirements of the project team. The simulation system fills the gap in the application of panoramic interactive technology in Marine engineering education, and provides a reference for the exploration of "intelligent +" experiment and teaching mode in maritime university laboratories.

Significant impacts of injection parameters on marine diesel engines

Nowadays, over 90% of the shipping industry mainly relies on marine transportation. The ability of 2-stroke low-speed diesel engines to consume heavy fuel and even crude oil makes them occupy an important position in the main propulsion power market. Also, it is quite convenient for them to operate reversely, which is needed for the astern situation. Compared with other propulsion power sources such as gas turbines or electro-propulsion, low-speed diesel engines have relatively better part-load performance and long-time stability, making them stand out. Most importantly, their efficiency can reach up to 60% when combined with exhaust boilers and turbine-driven alternators. The majority of those advantages are gained from the delicately designed fuel injection system and the governor system. This article discusses 2-stroke low-speed marine diesel engines' fuel injection systems and how some important parameters influence engine performance. Future opportunities and key challenges in this exciting field are also highlighted.

The Analysis of Effectiveness Electric Motor As A Main Propulsion In The Navy Ships

Electric motors as the main booster for ships are widely used in submarines. But now, it was used in the Navy Ships type of Xyz Class. In the world, there are quite a several warships that use electric motors as the main propulsion engines because they have high efficiency, especially in terms of maintenance budget requirements and fuel budgets. On the other side, During the operation at the Navy Ships, several advantages were felt both in terms of operation and maintenance. The electric motor was very useful to be used in Navy Ships type of Xyz because it was very efficient in fuel consumption when it was used as the main engine. Now, the Indonesian Navy has had two Navy Ships type of Xyz. And Indonesian Navy hoped that this kind of engine type can be useful and give more beneficial in the future, especially in helping its jobs.

Modelling of the availability for the ship integrated control system sensors

Innovative control systems regulate and adjust a lot of operational conditions of the modern ship’s functions. A comprehensive Ship Integrated Control System (SICS), for the operation of the propulsion plant, the power management of the auxiliary engines, the operation of the auxiliary machinery, the loading and unloading of cargo, the navigation, the management of maintenance and the purchase of spare parts is implemented in the paper. A strategy where preventive maintenance is carried out and different repair actions can be considered is proposed. The SICS is subjected to various levels of degradation, and if so, a repair process will be undertaken to restore the system to its full working state. The aim of the paper is to optimize the best strategy for the different sensors of the SICS where only maintenance actions are performed or only repair actions need to be carried out. The model is developed and applied to the sensors of a ship and the objective is to determine the optimal asymptotic availability, and in particular in the main propulsion plant of a Liquefied Natural Gas (LNG) carrier. The model is illustrated by a numerical example based on empirical data.

Speed control of marine main thruster motor based on super-twisting sliding mode variable structure

In order to solve the problem of torque-ripple in the control system of ship main propulsion motor controlled by direct torque control, this paper proposes a super-twisting sliding mode calculation method based on the traditional sliding mode controller, and designs the corresponding controller according to this method. The method is verified by Matlab/Simulink simulation tool. In the simulation waveform, the estimated speed of the super-twisting sliding mode control is almost consistent with the actual speed of the main propulsion motor, and the estimated rotor position is almost consistent with the actual rotor position of the motor, with small error. It is proved that this method has good practicability and effective feasibility in ship electric propulsion system, and provides theoretical reference for the design of ship electric propulsion system.

Performance Analysis of Combined Gas-Electric Steam Turbine System as Main Propulsion for Small-scale LNG Carrier Ships

Performance Analysis of Combined Gas-Electric Steam Turbine System as Main Propulsion for Small-scale LNG Carrier Ships

Significant Development Potential of the Solid Oxide Fuel Cell for the Technical Progress of the Marine Main Propulsion Plant in the Context of Energy Conservation and Emission Reduction

The International Maritime Organization (IMO) has proposed a series of strict pollutant emission regulations and carbon emission reduction targets, and the shipping industry is seeking new types of the marine main propulsion plant with advantages of high-efficiency and low-emission. Among the possible alternatives, the marine electric propulsion technology whose electric power source is fuel cell has gained sufficient attentions. At present, the worldwide research of the marine applications for fuel cell supplying propulsion power focuses more on the proton exchange membrane fuel cell (PEMFC) with low power instead of other types of fuel cell, and a series of research projects have achieved concrete results such as the industrialized marine fuel cell system or practical demonstration application. But the development trends of the application of the marine fuel cell supplying propulsion power are from the small boat to the great ship, from the navigating zone with low environmental complexity such as coastal water, inland waters to the ocean with complex navigation conditions. Thus, the power demand of the marine fuel cell in the future will show steady growth, which will create more development opportunities for the solid oxide fuel cell (SOFC) with the advantages of higher power, greater efficiency, long life span and fuel diversity. Although some challenges exist, the solid oxide fuel cell with significant development potential can certainly lead the technical progress of the marine main propulsion plant in the context of energy conservation and emission reduction.

Some Morphofunctional Features of the Tail of Early Archosaurs in Relation to Swimming Adaptation

In ancient and modern aquatic and semi-aquatic tetrapods, several types of structure of the locomotor apparatus are presented, providing various styles of swimming. In the course of evolutionary adaptation to swimming, an important role was played by the morphological transformations of the tail, which often performs the main propulsion function. Modern reptiles (except turtles) swim mainly with the help of horizontal tail bends, while mammals swim either vertical or horizontal ones. Among extinct reptiles, Sauropterygia probably used vertical tail mobility when swimming. In most archosauromorphs, the tail became high, laterally compressed, and they swam mainly with the help of its horizontal movements. Among early archosaurs, Proterohampsians and Doswelliids are distinguished by their wide and dorsoventrally flat tails, which may indicate an adaptation to swimming using its vertical mobility.