High-speed Marine Diesel Engines Research Articles

Temperature control characteristics of intelligent cooling system for high-speed marine diesel engine

ABSTRACT To improve energy conservation and reduce emissions of an engine, this study applies intelligent thermal management to a cooling system. With a marine high-speed diesel engine as the research object, an intelligent cooling system based on controllable cooling components was developed. A variable-universe fuzzy control algorithm is designed to control an electronic thermostat, and a ‘T–S fuzzy control + BP-PID’ control algorithm is proposed to control standard electric drive pumps. The experimental results indicate that the intelligent cooling system considerably reduces the warm-up time, achieves accurate cooling, and effectively inhibits the hot immersion phenomenon. The intelligent control algorithm has control characteristics such as rapid response, strong adaptive ability, small overshoot, smooth transition, and high precision. The intelligent cooling system reduced the cooling-system power consumption by 5.52%–57.93%, fuel consumption rate by 1.43%–5.15%, smoke emission by 1.40%–4.69%, CO emission by 2.14%–6.03%, and HC emission by 7.41%–12.26%.

Interactions between Used Cooking Oil Biodiesel Blends and Elastomer Materials in the Diesel Engine

Used cooking oil (UCO) biodiesel may be one of the most potential alternative fuels in China to lower the dependency on crude oil for transportation. An experimental study has been conducted to assess the interactions between biodiesel produced from UCO in Shanghai and elastomer materials on high-speed marine diesel engines by immersing elastomer materials into conventional fossil diesel, 5, 10, and 20%, of a volumetric blending ratio of UCO biodiesel and pure UCO biodiesel. The test duration is 168 h at different temperatures of 25, 50, and 70 °C. Meanwhile, the effects of the mixing ratio of UCO biodiesel and the immersion temperature on the compatibility of elastomer materials with UCO biodiesel were analyzed. The results revealed that elastomer materials such as nitrile butadiene rubber (NBR), ethylene propylene diene monomer (EPDM), fluororubber (FKM), and silicone rubber (SR) exposed to biodiesel blends would reveal worse but acceptable changes than those exposed to petroleum diesel, including the slight increase of mass and volume and decline of tensile strength and hardness. FKM, NBR, and SR represented better compatibility with pure UCO biodiesel than diesel, and EPDM showed worse compatibility with UCO biodiesel as the blend ratio rises. In general, the recommended volumetric mixing ratio of UCO biodiesel should be no larger than 20%. The present study could be helpful for the investigation of UCO biodiesel blends as a potential fuel to satisfy the energy demand.

Improvements of a Failure Database for Marine Diesel Engines Using the RCM and Simulations

Diesel engines are widely used in marine transportation as a direct connection to the propeller and as electrical principal or auxiliary generator sets. The engine is the most critical piece of equipment on a vessel platform; therefore, the engine’s reliability is paramount in order to optimize safety, life cycle costs, and energy of the boat, and hence, vessel availability. In this paper, the improvements of a failure database used for a four-stroke high-speed marine diesel engine are discussed. This type of engine is normally used in military and civil vessels as the main engine of small patrols and yachts and as an auxiliary generator set (GENSET) for larger vessels. This database was assembled by considering “failure modes, effects, and criticality analysis (FMECA),” as well as an analysis of the symptoms obtained in an engine failure simulator. The FMECA was performed following the methodology of reliability-centered maintenance (RCM), while the engine response against failures was obtained from a failure simulator based on a thermodynamic one-dimensional model created by the authors, which was adjusted and validated with experimental data. The novelty of this work is the methodology applied, which combines expert knowledge of the asset, the RCM methodology, and the failure simulation to obtain an accurate and reliable database for the prediction of failures, which serves as a key element of a diesel engine failure diagnosis system.

Marine diesel engine failure simulator based on thermodynamic model

The diesel engine is a widely used machine in naval sector both as a propeller and auxiliary generator sets, being the most critical equipment of vessel platform. Therefore, diesel engine reliability optimization has a transcendental impact on vessel availability, safety and life cycle costs.This article describes the development of a 4-stroke high speed marine diesel engine failure simulator used in military and civil vessels as the main engine of small patrols and yachts and as an auxiliary genset for larger vessels. Failure simulator is based on a one-dimensional thermodynamic model developed in AVLBoost©, adjusted and validated with experimental data from a real engine in a test bench.The developed model is able to reproduce with confinable results the effect of a large number of typical thermodynamic failures, the behavior of the engine and the effects over several parameters measured and non-measured. Therefore, it is possible to obtain the engine response to failures without having to provoke them in real engine and also it is possible to know the symptoms of one failure before this failure becomes dangerous for the correct behavior of the engine. In addition, this paper exposes a methodology which allows to obtain a failure simulator of any marine diesel engine. This simulator is able to identify diesel engine symptoms under failure condition and build a reliable failure database for diagnosis purposes.

СИСТЕМЫ МОНИТОРИНГА СУДОВЫХ ДИЗЕЛЕЙ В ЭКСПЛУАТАЦИИ

The article provides an overview of currently used diagnostic systems of medium- and high-speed marine diesel engines. The parameters controlled by diagnostic systems have been discussed. The advantages and disadvantages of the monitoring systems of marine diesel engines designed as a single software-hardware complex have been analyzed. As it has been stated, universal monitoring systems for engines of different models are not created. Specialized diagnostic systems are only installed in powerful engines which are used on sea-going ships, not on river vessels and mixed (river-sea) navigation vessels; such complexes have not been applied so far. According to the results of the analysis, there have been listed engine diagnostic parameters required for implementing algorithms of automatic diagnostics without disassembling. The paper presents a review of commercially available sensors for measuring parameters of engines in operation. It has been shown that currently the decision of tasks of technical diagnostics of marine engines and, therefore, other less complex mechanisms of a ship power plant on the river vessels is possible because of modern electronic control systems that allow continuous monitoring of technical parameters, i.e. collecting and processing information received from sensors of the controlled variables and processes.

Study on torsional vibration characteristics of small high-speed marine diesel engine crankshaft system with viscous friction damper

Study on torsional vibration characteristics of small high-speed marine diesel engine crankshaft system with viscous friction damper

Расчет теплового и напряженно-деформированного состояния моноблока быстроходного судового дизеля

Расчет теплового и напряженно-деформированного состояния моноблока быстроходного судового дизеля

선박용 고속 디젤엔진에 적용한 디젤미립자 필터의 측정방법에 따른 입자상물질 저감효율 비교 연구

본 연구에서는 입자상물질 저감을 위해 개발한 디젤미립자 필터를 선박용 고속 디젤엔진에 적용하여 측정방법에 따른 저감효율을 비교 분석하였다. 시험에 사용된 엔진은 최고출력 403 kW의 4행정 기계식 선박용 고속 디젤엔진이며, 선박 엔진의 부하와 회전속도 제어를 위해 AC 동력계를 사용하였다. 선박 엔진 시험주기인 E3 cycle의 네 운전조건에서 저감효율을 측정하였으며, 측정방법으로는 입자상물질 및 soot의 저감특성을 살펴보기 위해 분류희석 방법과 광흡수법이 적용된 계측기를 각각 이용하였다. 디젤미립자 필터 적용에 따른 저감효율 측정 결과, 엔진허용 배압을 충족함과 동시에 입자상물질의 경우 76 ~ 91 %, soot(≈블랙카본)은 90 %이상 확인할 수 있었다. 이 결과로부터, 선박용 디젤엔진에서 배출되는 입자상물질 및 soot 저감기술로 디젤미립자 필터 적용 가능성을 확인할 수 있었다. 또한, 측정방법별 저감효율이 상이한 결과로부터 측정방법의 단일화 필요성을 확인할 수 있었다.

The Valve Gear Systems Timing Parameters Identification for Marine Diesel Engines Diagnostics / Identyfikacja Parametrów Układów Rozrządu Silników Okrętowych Dla Potrzeb Diagnostyki

Abstract In the paper results of studies that aim was to develop a diagnostic method for high-speed marine diesel engines are presented. Polish Navy is operating significant number of engines of this type also on board of submarines. Engines of this type do not have indicator valves, which complicates the assessment of combustion process and their technical condition. Polish Naval Academy in Gdynia for years has been developing methods of diagnosing marine internal combustion engines. In recent years, a diagnostic method for high-speed marine diesel engines based on the analysis of envelope of vibration accelerations generated by the valve gear mechanism and fuel system has been developed. Some tests results made on Mercedes-Maybach MB820 engines used on Kobben class submarines are presented in the paper.

Application of HFRT Methods to Diagnose the Technical Condition of High-Speed Marine Diesel Engines

The paper presents problems related to testing of the technical condition of high-speed marine diesel engines that are not equipped with indicated valves, as it is in the case of larger medium-and low-speed marine internal combustion engines. In this case, in assessment of technical condition of engine fuel injection system and valve gear system a vibration signals (in time / angle domain) analysis modified method called HFRT (High Frequency Resonance Technique) can be used. This method indirectly helps also to evaluate the fuel combustion process in the engine cylinders. The paper presents the theoretical basis of a modified HFRT method, physical implementation of the marine diesel engine system’s analyzer used for marine engines testing built at the Institute of Construction and Operation of Ships at Polish Naval Academy (PNA) in Gdynia. The paper also includes a description of the vibration signal processing methodology and examples of measurements made in the ships conditions for a few selected types of engines.

Miller-Cycle Regulatable, Two-Stage Turbocharging System Design for Marine Diesel Engines

The increasingly stringent NOx emission regulations of the International Marine Organization (IMO) have demanded new design concepts and architectures for diesel engines. The Miller cycle, which reduces the in-cylinder combustion temperature by reducing the effective compression ratio, is the principal measure used for reducing NOx specific emissions; however, this is at the cost of volumetric efficiency and engine power. Therefore, it is essential to combine the Miller cycle with a highly boosted turbocharging system, two-stage turbocharging for example, to recover the power. While much work has been done in the development of Miller-cycle regulatable two stage turbocharging system for marine diesel engines, there are nonetheless few, if any, thorough discussions on system optimization and performance comparison. This study presents a theoretical optimization design process for a Miller-cycle regulatable, two-stage turbocharging system for marine diesel engines. First, the different scenarios and regulation methods of two-stage turbocharging systems are compared according to the system efficiency and equivalent turbine flow characteristics. Then, a multizone combustion model based on a one-dimensional cycle simulation model is established and used for the optimization of valve timings according to the IMO NOx emission limits and fuel efficiencies. The high- and low-stage turbochargers are selected by an iterative matching method. Then, the control strategies for the boost air and high-stage turbine bypass valves are also studied. As an example, a Miller-cycle regulatable, two-stage turbocharging system is designed for a highly boosted high-speed marine diesel engine. The results show that NOx emissions can be reduced by 30% and brake specific fuel consumption (BSFC) can also be improved by a moderate Miller cycle combined with regulatable two-stage turbocharging.

低酸素・高加湿給気によるNOxの80％低減

By 2016, under the IMO Tier III rules, NOx emissions from ships sailing in emission control areas (ECA) should decrease by more than 80% relative to IMO Tier I levels. In this study, in order to reduce NOx emissions from marine diesel engines, a low-oxygen and high-humidity system for suction air was connected to the suction line of a high-speed marine diesel engine, and the influence of oxygen density and moisture content in suction air on NOx emission was investigated. The following results were clarified. (1) NOx emission decreases with a decrease in oxygen density for each load factor, and it is necessary to adjust the oxygen density to 17% or less to comply with Tier 3 regulations. (2) NOx emission decreases because oxygen density decreases with an increase in moisture content. The regulations can be complied with by adjusting the humidity of suction air to 16 mol%. (3) NOx emission can be effectively reduced by decreasing both oxygen density and suction air humidity, taking into account the operating conditions of the engine.

원형 고무 세그먼트를 갖는 탄성커플링의 동특성과 적응성

Medium and high speed marine diesel engines with reduction gear have been widely used as prime mover in small car ferries and fishing vessels. The elastic coupling should be installed and complemented the propulsion shafting system to isolate the vibratory torque between engine and reduction gear. In this paper, the dynamic characteristics of elastic coupling with rubber type circular segments is confirmed by theoretical analysis using the FEM and the hydraulic excitation test at shop. Further adaptation was investigated with the torsional vibration test at diesel engine factory shop.

非燃焼時のシリンダ内圧力を用いたTDC位置の正確な決定法について

A wrong TDC position leads to incorrect cylinder pressure-crank angle phasing, and has been recognized as a major source of error in thermodynamic calculation results such as indicated mean effective pressure, heat release rate, or thermal and mechanical efficiencies. One of the most convenient ways to determine TDC is to use measured cylinder pressure obtained from a pressure transducer under non-firing conditions. However, it is impossible to determine TDC precisely because the thermodynamic loss angle is unknown. In the paper a new method for TDC determination based on a measured non-fired cylinder pressure versus time diagram has been presented. In this method there is no need to know the details of the heat transfer formula, heat transfer coefficients or the properties of working gas in the engine . The method is applied to a four stroke high-speed marine diesel engine successfully. This method is distinguished for its high accuracy and is also probably applicable to large two stroke diesel engines.

SIPHONING SEA WATER BACK INTO THE ENGINE IN FAST BOATS

A failure investigation has been conducted on the exhaust system of a high speed marine diesel engine in Turkish ambulance boats. Premature failures were reported on the poor starting, on the loss of power, on the lubricating oil leakage and on the engine overload. It was observed some significant tracks of sea water found its way into the exhaust passages from condensation of the salt water vapour and also from entering some sea water into the exhaust system. In order to initiate a more accurate cause investigation, the engine went through an overhaul inspection, in which it was determined that there were corrosion and some deposits throughout the exhaust system. After performing the systematic cause analysis of the engine damage, it is concluded that erroneous design decisions cause to siphon sea water back into engine, doing expensive damage. Ever since water has been used to cool exhaust gases, there will be many cases of engines flooding with water from the exhaust system. Recognizing the potential problems mentioned in this paper, a wet-exhaust system is recommended to keep water out of all small and indoor marine propulsion engines.

鍛造クランク軸の超高サイクル疲労強度に及ぼす鍛造フローの影響

The CGF (Continuous Grain Flow) forging method is widely applied to crankshafts of high-speed marine diesel engines in recent years. CGF-forged crankshafts are considered to have an advantage in fatigue strength compared with free-formed forged crankshafts because of two factors: 1) continuous grain flow along the axial direction of the shaft, and 2) small segregation of impurities in the surface layer of the shaft. In general, however, the forged grain flow of CGF-forged crankshafts has a local discontinuation at the fillet between the crank-pin and the crank-arm or between the crank journal and the crank-arm, which originates in the shaft machining process. In this study, effects of the local discontinuation of the forged grain flow on the ultra-high-cycle fatigue strength were investigated by fatigue tests and by FEM calculations. Based on the investigation, it is clear that the effects of continuous grain flow on the fatigue strength are invalid in the event that a local discontinuation of the forged grain flow at the fillet exists.

高速舶用機関の負荷特性に関する研究（航行中の機関負荷特性とシリンダ内圧力の解析）

Due to short passages and fast turns, the high-speed marine diesel engines for high-speed vessels, passenger ships, and ferries operate under severe conditions of frequent starts, rapid acceleration, and hot shutdown. We consider that various failures of high-speed diesel engines are associated with such maneuvering patterns of high-speed vessels.In order to determine the load characteristics of high-speed engines during operation, full-scale measurements of a fast ferry with a water-jet were carried out. The shaft output and in-cylinder pressure of the engine were measured continuously from engine start to shutdown.The data acquisition method is described, and the transient performance of engine load, from harbor to cruise maneuvering, and characteristic relationship between power absorption and shaft speed of the water jet are presented. An engine performance analysis using in-cylinder pressure in various running conditions is also presented.

船舶におけるＰＭの計測

In order to establish the measuring method of particulate emission from marine diesel engines during voyage, following two experiments were carried out. (1) Trial to measure the particulate emission from a 2342 GT experimental ship equipped with a 2795 kW 2-cycle marine diesel engine and a controllable pitch propeller. (2) Trial to clarify the effect of measuring procedure of particulate emission using a high-speed marine diesel engine on the test bench. For both the ship and the test engine, same partial-flow dilution tunnel was applied.Results obtained from the examinations are as follows.(1) According to the measured emission data from the experimental ship, the higher the engine load was, the more particulate emission (g/kWh) was emitted both with propeller and generator characteristics.(2) It was also confirmed that measuring the output horsepower accurately on board was as important as measuring the accurate particulate emission because the data should be evaluated as g/kWh same as the data on the test bench.(3) As a result of the examination on the measuring procedure using the high - speed marine diesel engine, the effect of filter loading, dilution ratio, shape of sampling probe, length of sampling line were clarified.

舶用ディーゼル機関における低質燃料油の排出ガス特性に関する研究

Recently the air pollution caused by marine diesel has become a more serious problem. For such engines heavy fuel, e. g. bunker fuel oil, is usually used. High residual portion and long ignition delay are the main disadvantage of heavy fuel. Their effects are especially severe at low load, which is the running condition of ships near the seashore where the pollution is a more serious problem.In this study the emission from a relatively high speed marine diesel engine using heavy fuel is examined. Because the effects caused by heavy fuel can be observed more clearly on a high speed diesel engine, such one was used for the experiments instead of a low speed engine.The experiments show clearly that heavy fuel causes higher smoke density than gas oil. The higher smoke density is caused by direct impingement of the unevaporated residual portion onto the piston.On the other hand the effect of heavy fuel on NOx emission can not be explained simply, because it is influenced by two counteracting effects : the higher pre-mixed combustion rate, which increases NOx formation, and the later ignition timing, which decreases it.

Design and Performance of a Variable Valve Timing System on a Highly Turbocharged Diesel Engine—Experimental and Predicted Results

A previous study using a cycle simulation program had identified the possibility that highly rated diesel engines might benefit from a variable valve timing (VVT) system. In particular, the study had shown that, by delaying the start of inlet valve opening at part load, it should be possible to eliminate the reverse flow that can lead to inlet port fouling. The work reported here encompasses the design and implementation of a variable valve timing system on a highly rated high-speed marine diesel engine. The principal topics addressed are the selection and design of a mechanism, a comparison between the predictions and results from mechanism testing on a single-cylinder valve-train rig and the engine performance predictions and results obtained when the mechanism was tested on the engine. The results from the single-cylinder test rig demonstrated that the mechanism performed satisfactorily, and this led to a design suitable for retro-fitting to the engine. The engine was comprehensively instrumented and the experimental results were in good agreement with the cycle simulation predictions.