The simulation model was based on a marinediesel engine (6S35ME-B9). The structure of marinediesel engine has been introduced in published paper . The experimental data were obtained when the engine speed was 142 r/min using HFO. The spray model and combustion model were validated with experimental data due to the different physical properties of diesel and heavy fuel oil . The physical properties of HFO were obtained from the Kyriakides’s model, which includes the dynamic viscosity, surface tension, vapor pressure, heat of evaporation and specific enthalpy . The spray model was validated with the experimental data in a rotational flow constant volume combustion chamber [9, 10].
The fuel used for engines is mainly petroleum distillate, which is a complex mixture of different carbon hydroxide groups. Based on the nature and structure of carbon hydrogen molecules classified into 3 groups: straight-chain hydrocarbon (full and unsaturated); cyclic carbon hydrogen (naptalin); Aromatic carbon hydrogen. Straight-chain carbon hydride: especially hydrogen carbonate (carbon monoxide especially napraphin or alkanes) has the highest self-ignition ability. Aromatic carbon monoxide of benzene has the lowest self-ignition ability. Naphthalene carbon monoxide has the ability to spontaneously ignite between these two families. The content of naphthal hydrocarbon present in the composition of the fuel makes the fuel viscosity increase. The chemical composition of the group indicates the different percentages of carbon monoxide groups in the composition of the fuel. The content depends on the composition of the fuel. Distillate fuel contains about 30-55% hydrogen carbonate, 5- 15% hydrogen carbon naphthal, 30-50% aromatic hydrocarbon, with heavy fuel containing 5- 50%, 40-70% and 10- respectively 25%. The chemical composition of the group allows to assess the ability of the fuel to ignite itself compared to the ability of spontaneous combustion of different fuels. The higher the composition of hydrogen carbonate fuel and the less aromatic hydrocarbon hydrogen, the higher the probability of spontaneous combustion (assessed by the number of dissipation). With marinediesel engines often use 2 types of fuel produced from petroleum: distillate fuel and heavy fuel. The low viscosity fuel can therefore not need to be heated before it is fed into the diesel engine cylinder. This type of fuel is called diesel fuel and gas turbine fuel. Diesel fuel obtained during direct distillation of petroleum including distillation mainly boils at a temperature of 230-3450C. Gas turbine fuel is the fuel obtained by the slow cup method from the asphalt crackin of the remaining substances of sulfur oil. This type of fuel has a low ash content, negligible mechanical impurity content, but high sulfur and resin content. Heavy fuel is a
Gas emission calculation is shown on the example of the Yugoslav river shipping with two methods for calculating harmful emissions of the marinediesel engines. Technologies for reduction of harmful emissions of marinediesel engines and other engines are also presented, as well as the implementation of those technologies, using the example of the Yugoslav river shipping. One of the objectives of this paper is to determine the actual condition of the fleet, as well as the impact it has on air pollution in Serbia, as a country which plans to become a member of the European Union. A measurement on diesel engines of different production date was done with a special device, in order to get the results that represent reality (about harmful emissions) in Serbia. Final task of this paper is to collect information in order to reduce harmful emissions of the marinediesel engines, along with preservation of the environment.
The different Miller cycle patterns were simulated to research the effect on the marinediesel engine performance and emissions. The 5°CA was used as interval angle of exhaust valve delay close time. So, the four methods were named as M5, M10, M15 and M20. The scavenging pressure was improved to offset the loss of fresh charge. Fig.5 shows the changes of intake pressure and air-fuel ratio under different Miller cycle. The intake pressure increases with delaying of exhaust valve close time, which can makes the equivalence ratio almost same for the Miller cycle.
There are differences among marinediesel engine 4-stroke and 2-stroke air input during the process. 4-stroke diesel engines are using the inlet valve to allow air to enter the combustion chamber. While the 2-stroke diesel engines using scavenge hole for supplying air into the combustion chamber. Scavenge methods on marinediesel engine 2-stroke is divided into three types, namely the type of cross flow, loops and uniflow as illustrated in Figure 2.3. These three types of scavenge method each have advantages and disadvantages. Cross flow type method requires piston skirt to prevent air and exhaust gases out when the piston is at TDC. While the loop is designed for low air temperatures and high temperature exhaust gas through holes adjacent to each other. This is necessary to avoid differences in temperatures far wall liner.
Abstract – There are many factors that affect engine performance in the laboratory, such as atmospheric environment, water temperature, oil temperature, fuel inlet temperature, air density and charge temperature before intercooler. In order to make it convenient for the laboratory to set up these environmental control settings in the future and to study and analyze the results of dynamic performance and economy changing with these environmental factors when the marinediesel engine is actually used. In this paper, on a Z6180ZLCZ-1 six cylinder, four stroke marinediesel engines, the ambient atmospheric pressure (102.0Pa) of the marinediesel engine is not changed, through several groups of comparative tests; the control variable method is adopted. This paper studies the influence of the temperature of supercharging before intercooler, the temperature of fuel oil entering engine, atmospheric environment and water temperature on the power and economy of marinediesel engine, and obtains the trend of the power and economy of marine engine changing with the environmental conditions of the laboratory.
Aiming at the problems of high operating cost, high training cost and large site requirement of traditional marine engine platform, the software of fault diagnosis system for marinediesel engine intake and exhaust system is developed by using Visual Studio 2012 platform. The relevant mathematical model is established by numerical method, and the conversion from mathematical model to code is realized to simulate the working status of marine intake and exhaust system in normal operation and failure. The results show that the simulation system runs well with low cost and small site requirement. It can accurately simulate the normal operation and fault state of the ship intake and exhaust system. It can be used for training work and improve the actual response ability of the trainers to the fault of the ship intake and exhaust system.
In marinediesel engines, to cool the oil, heat exchangers are widely used. These heat exchangers are placed in the oil chamber and utilize the sea water for cooling the engine oil. Components of this cooling system can be seen in Figure 1(a). According to this figure, the heat exchanger includes tubes and a shell. The engine oil moves through the shell and the sea water moves through tubes. Tubes, made of 316L stainless steel are brazed to the tube sheet made of brass. There are also some baffles to cause turbulence for better heat transfer.
86%, 11% and 96% respectively , Figure 6. However, methanol raises the possibility of corrosion and must be faced with adequate upgrading of fuel sto- rage tanks. On the other hand, LNG retains about 85% of the energy stocked per unit volume compared to traditional oil fuel. One of the most vital challenges of the use of LNG as a marine fuel, is the higher size of his tanks (3 - 4 times great- er) than the marinediesel oil tanks . This further increases the costs of in- stallations for a retrofit. Recently, a study conducted and published by DNV-GL , confirms that LNG-fueled fleet will increase very-quickly over the next years, especially in zones with existing bunkering abilities. Moreover, a previous study assessed by Wärtsilä in order to evaluate the advantages of changing from HFO fueled engine equipped with a Sea scrubber to LNG fueled engine  has shown additional savings from the annual machinery cost (maintenance, oil lu- bricating, scrubber and SCR with annual capital) by an amount of 500 $/kW. Furthermore, the expansion in navigation time in emission control areas (ECAs) where high quality fuel is required will add more economic interests to LNG than HFO-powered engines where stricter emission regulations are approved and implemented. Figure 7 shows price comparison between HFO and LNG for three engine grades conforming to the current fuel price (January 2019), is about 15.3$ US/MMBtu for HFO and 11.6$ US/MMBtu for LNG.
In the present paper, two different ways of modelling a large two-stroke marineDiesel engine using cycle mean value models are presented. According to the first approach, the engine crankshaft and turbocharger shaft speeds are obtained by solving the angular momentum conservation differential equations. The other engine variables are obtained as solutions to a nonlinear algebraic system of three equations corresponding to energy and mass conservation across the engine. According to the second approach, the engine scavenging and exhaust receivers are modelled as open thermodynamic systems. The mass, temperature and pressure of the working medium contained in the engine receivers are calculated using the mass and energy differential equations and the ideal gas law, respectively. For representing the engine turbocharger compressor and turbine, their maps, derived under steady state conditions are used. The engine cylinders are modelled using a cycle mean value modelling approach to calculate the average mass flow and enthalpy rates of the exhaust gas exiting the cylinders and entering the exhaust receiver. Engine crankshaft and turbocharger shaft speeds are obtained using angular momentum conservation. The simulation
A thermodynamic model is presented for predicting oxides of nitrogen (NOx) emissions from slow speed marinediesel engines. The model is zero-dimensional, uses chemical kinetics for NOx formation in multiple burnt gas zones, and runs in real time on a standard PC. The mean fuel/air mixture strength at which NOx forms and the rate of dilution of the burnt gas by unburnt air, are adjustable. Two MAN B&W IMO NOx-compliant slow speed diesels are modelled. Effects such as variations in fuel spray interaction with load are accounted for in the calibration of the model. The effect of dilution rate and equivalence ratio on NOx formation is studied. It is shown that, under certain conditions, there is a critical burnt gas dilution rate which maximises NOx. The model responds adequately to changes in engine load and to NOx control measures such as water injection, injection timing retard, exhaust gas recirculation and humidification.
In this respect, several definitions are provided for both maintenance and reliability terms by various authors summarizing the notion that maintenance is a set of technical, administrative and managerial actions targeting to retain or restore the state of a system to function as required. In further nowadays, maintenance is encountered as an operational method, which can be employed both as a profit generating process and a cost reduction budget center through an enhanced Operation and Maintenance (O&M) strategy. In this respect, a broad exploration of maintenance methodologies takes place, concerned with the most known methods and techniques scoping to motivate the development of an optimized, innovative and applicable maintenance strategy for marine engineering systems.
Investigation in CFD was performed on four parameters comprises manifold temperature, manifold pressure, exhaust piping system temperature and atmosphere pressure. Results of CFD simulation was showed in the form of pressure and velocity contours and streamline. This study found the modification of exhaust piping design of the 4-stroke marinediesel generator increased the backpressure. By verifying the results obtained here we could observe that the modified model with stainless steel has obtained the better results output when compared with the original
camshaftless low-speed, two-stroke DF engine consisting of five cylinders connected in an in-line arrangement, one turbocharger unit and one air cooler unit. It employs a common rail diesel fuel injection system and gas injection at low pressure during each cylinder compression phase. The engine can operate in diesel mode by using heavy fuel oil or marinediesel/gas oil. In DF mode, natural gas is used as the main fuel while diesel fuel is utilized as pilot fuel in order to start the combustion process. When running in DF mode, the engine is fully compliant with the IMO Tier III NOx emission limits.
In this paper, the application and control system of marine intelligent diesel engine are studied. Nowadays, more and more attention has been paid to energy saving and emission reduction of ships. Intelligent diesel engine will inevitably become the mainstream of marinediesel engine development. Intelligent diesel engine, represented by RT-flex diesel engine, is becoming more and more perfect in the application of electronic common rail technology, and its models are constantly updated. With more and more ships equipped with intelligent diesel engines, especially advanced ocean-going transport ships, the management level of marine engineers is becoming higher and higher. For marine engineers, it is necessary to understand and familiarize themselves with the technical characteristics of the main engine type RT-flex diesel engine of ship main engine in the future.
The degree of speed control of ship machinery effects on the economics and optimization of the machinery configuration and operation. All marine vessel ranging need some sort of speed control system to control and govern the speed of the marinediesel engines. Impractical and dangerous to have a ship or boat without speed control mechanism fitted on it, and could lead to accidents such as collision or grounding. Traditionally, engine speed regulation is achieved using classical gain-scheduled PID control to address the variable operating conditions of the engine. In this paper we present a mathematical model to describe the rotation speed regulation process of a marinediesel engine and the parameters of PID controller are optimized by Genetic Algorithms (GA). The result of simulation shows that the Genetic Algorithms (GA) is able to improve operational reliability and efficiency of marinediesel engine.
In past time, the maritime industry paid little attention to air pollution. That attitude was changed when IMO adopted Annex VI to MARPOL 73/78. Annex VI is concerned with the prevention of air pollution from ships. Because of the transboundary effect of air pollution, and the compelling need for many countries to tackle the growing problems of its effects on human health and global environment, IMO agreed to recommend the early implementation to reduce the emission of NOx from new marinediesel engines. It has also been agreed that, in order to avoid unacceptably long delays in the entry into force of Annex VI, the MEPC will review the impediments to entry into force of the Protocol and any initiate necessary measures to alleviate those impediments, as a matter of urgency, if it has not entered into force by 31 December 2002. Therefore, there is no doubt that Annex VI will enter into force in the future.
Both the FRP trawlers were fitted with Ashok Leyland make AL-370 model inboard marinediesel engine, having horse power below 100 hp for 40 footer trawler and 106 hp engine for 50 footer trawler. Kunjir 2004 reported that engines with horse power of 87-106 hp were fitted on trawlers operating from Mirkarwada and Sehara et al. (1991) had reported the same observations with respect to the engine type as that observed during present study.