Marine Diesel Engine Reliability Analysis

Diesel engine is the heart of a ship as it is the impetus of the ship. A safe, fast, superior-service and economy oriented sailing of a ship basically lies in the safe and dependable performance of the diesel engine. The main diesel engine is the most valuable and necessary equipment integrated into a civil ship, and its reliability has a direct and economical impact on a ship operation. A ship diesel engine is easy to get broken down due to its sophisticated structure and unfavorable working conditions. During an ocean voyage, it is not so easy to have either a broken-down main engine restored or the needed spare parts supplemented promptly. Thus, various kinds of incidents, loss of lives and property or pollution of the sea area will occur. The fast development of ship building industry has set a still higher demand on the manufacturing technology of a diesel engine, so has it on costing and reliability of a diesel engine. In view of its inferiority in both reliability and endurance, top priority has been given to improvement of the above weakness of a internal-combustion engine (including diesel engine) nationally since the 1990s.The above task is a systematic project, as there are various factors relating to designing, technique available and individual operation, which will no doubt affect the reliability of a diesel engine. Focus has been drawn on increase of the reliability of the motive apparatus itself by efforts from manufacturers themselves via a variety of means, and continuous endeavors have been made to improve its structure, the reliability of its spare parts and to provide a complete set of models. Nevertheless, all these efforts haven't been able to solve the problem completely. It has gradually been realized that the traditional method based on isolated analysis can far not meet the requirement of development of the modern shipping industry. Therefore firstly, a research shall be conducted to decide degrees of reliability of a diesel engine by its nature and quantification; secondly, both modern managerial ideology and technology in the engineering field shall be applied systematically in the stages of a diesel engine's designing, building, fixing and operation in order to achieve its higher reliability; thirdly, a crewman is required to have not only good knowledge of performance and operation, but also a good understanding of its principle and structure design. It is also a necessity for a crewman to be well aware of the regularity of causes to a breakdown, and have a good master of skills for management and maintenance of the machine. The thesis carries on a discussion on the subject. The issue of reliability goes through the whole process in individual stage of designing, building, testing, operation and maintenance. All these stages including reliability designing, building, testing, endurance anticipation and assessment are covered in the research. Based on the reliability theory and the statistical approach of the applied probability, and the basic notion of reliability of a diesel engine, the paper has given an analysis both by the nature and quantification of the reliability of a diesel engine, and outlined reasonable criteria for assessment of both diesel engine and its spare parts. The paper has also tried to conduct the research from both the general features of a broken-down engine and impacts from surroundings. An analysis of endurance has also been given with the view to finding out its defects so as to have a more accurate anticipation of its endurance period. With the help of the first-hand datacollected, the paper analyzed the relationship between the reliability of a diesel engine and its whole motive system, including its maintenance, operation, spare part supplement so as to have a good command of the integrated reliability of the motive power of a ship, and establish assessment approach from the perspective of affect from the reliability of an individual part to the whole integrated system. From the view point of systematic engineering of crewman-machine relation, the paper analyzed in an all-round way the complicated conditions on a ship where crewman, machine and surroundings are all interrelated. From the aspects of both human beings (crewman) and materials (machine, surroundings, management), all segments of the system that might affect the reliability have been outlined and an analysis has been followed. The thesis has also given a brief introduction of the roles of a crewman, machine and the surroundings under the context of mechanical system on a ship, with an analysis of affects of artificial factors on the reliability of the machine, and at last put forward effective measures of improving reliability of motive apparatus of a ship diesel engine.