Marine Diesel Engine

By Christina Murphy,2014-09-17 19:03
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Marine Diesel Engine

    Marine Diesel Engine

    First, the status and development trend of marine diesel engine

     (A)The development of profiles of foreign diesel engine

    Over the past decade, marine diesel engines towards increased power, lower fuel consumption, improve reliability, reduce wear, extend life, reduce noise and vibration, reducing the weight and size, easy maintenance, the implementation of automatic monitoring direction. Since 1973, soaring world oil prices after reducing diesel fuel consumption has become the focus of competition between manufacturers.

1in progress to improve the power aspects:

    As the pressurized process of technological progress and work to improve, single cylinder and single power rising. The largest single-cylinder power from 20 years ago 1100kw embankment south 3680kw. Currently, the largest single power reached 36899kW. Power increases mainly by rising average effective pressure Pe to achieve, four-stroke diesel engine of Pe reached 2.6MPa, two-stroke diesel engine of Pe up 1.575MPa.

    2In improving the economic aspects:

    Since the oil crisis, soaring fuel prices, fuel costs greatly increased. Fuel cost percentage of total operating costs increased 40% from 20 to 40 ~ 60%, thus, lower fuel consumption, burning poor quality fuel, look for alternative fuel has become the engine of foreign competition, the primary means of manufacturing companies. The company has been carrying out extensive experiments, and obtained great progress.

    Low-speed diesel engines dominate the world market, B & W and SULZER company, from 1977 to l982 years, so that low-speed two-stroke diesel engine fuel consumption rate has dropped by 27g/kW.h, the lowest level of fuel string to 160g/kw.h. Marine medium speed diesel engine fuel consumption rate has also significantly reduced. France PC2-6EF, and PC4-2EF models of fuel consumption rate has reached 170g/kw.h. Their effective thermal efficiency he = 0.5 ~ 0.53, reached a very high level.

    In recent years, low-grade fuel 11 Fuel oil (also called residue) has been the host or the auxiliary vessel to be used as the main fuel. Low-speed two-stroke diesel engine fueled with heavy oil viscosity reached 3500 a 6000 seconds (mine's at (100 ? F)). Four-stroke medium speed diesel fuel with a meal at Ray's degree of 1500 a 3500 seconds of heavy oil. High-speed diesel fuel with a viscosity of 200 at Ray's 250 seconds of a heavy oil. Shipyard hope with the same host and auxiliary fuel. 3Improve reliability, extend life, the development of monitoring system

    With the increase in the average effective pressure Pe, the maximum pressure has been up to the outbreak of 15MPa. Components increased mechanical load and thermal load, to improve reliability and service life, reduced thermal stress and mechanical stress, high temperature surface to enhance the cooling, improved materials, improved structural rigidity and other aspects of raising a lot of work, and made progress.

     Develop electronic monitoring system. Performance of the diesel engine parameters and operating conditions the instantaneous change in the trend analysis in order to choose the best operating parameters and the timely detection and troubleshooting or unreliable factors, Liao Jie parts operation, and failure by measuring the harbinger of analysis to determine the components of Genghuan period. In addition, widespread use of computer at home and abroad to assist the design and structural strength testing research. No doubt this engine optimization and structure of the program requirements according to life the most economical design that is effective means.

    Modern diesel engines overhaul of (life) greatly improved, high-speed high-power diesel engine for the 5000 ~ 6000h (hours), medium-speed diesel engine power is generally 30000h, individual models such as the TM410 medium-speed machines and low-speed machines can be compared to life 72000 ~ 100000h, the equivalent of 10 to 20 years. In the past two decades, various types of diesel engines have achieved great development, single-cylinder power was the doubling of the growth. In this regard, turbocharger played a decisive role. Also being mean effective pressure to further improve a lot of research.

     (B)Overview of China's internal combustion engine

    Before the liberation, due to the long closed by the imperialist aggression and oppression of the establishment of justice, science and technology and various industries have not been properly developed, external-combustion engine manufacturing industry is no exception. From 1901 to 19,494 when New China was

    founded nearly five decades, has been produced in total gasoline and diesel engines power a large number of less than the current annual output of the plant. And they can make some important components, depends on foreign imports. This shows that the old China left an internal combustion engine industry, it is very backward, very weak. After liberation, socialist economic construction in China has made great achievements. Diesel engine industry has developed rapidly. In 1958, China's first diesel engine designed for 135 successful trial, designed to open up the engine of our broad road. 30 years, China has been able to design new models from small to large, from low speed to high speed about 70 kinds of. Now, China had to design and manufacture of diesel engines of all types and uses. Bore from the D = 65mm to D = 760mm. Single power minimum Ne = 0.35kW, a maximum of Ne = 45000kW. Speed range of n = 115 ~ 3000r/min, higher performance products are being developed. In 1987 the annual output of gasoline and diesel has reached 64.37 million dry tile. In the fifties, the majority of our diesel engine is a generic product, performance is relatively backward, from the early sixties to the present, high-volume production of first generation, second generation diesel engine designed to improve its performance greatly. On medium and small-power high-speed diesel engine, the contrast of old and new products, power increased by 20 ~ 50%, the average effective pressure increased by 30 ~ 40% higher fuel consumption rate has dropped by 10 to 20%, some of which performance of products reached a higher level. For example, machines and Z12V190B 6135ZLCa engine type, etc., has reached the level of similar products. China's production of high-speed machines are 12V150 series, light 12v180 machine, re-12V180 machine, light 42-160 machines. They are used in boats, ships and military vehicles.

    In the medium-speed diesel engine power, the success of our country's own 12V240 machine, the 300 series machines, 12V390 and other models are representative of the product. Their performance at or near the same type of products of foreign advanced level. In addition, China has also produced other types of medium-speed machine.

    Our country's own production of large-scale low-speed machine has 6ESDZ43/82B type, 6ESDZ75/160B type, 6ESDZ76/160 type, 9ESDZ50/100 diesel engine type and so on. They are from the Shanghai Hudong Shipyard and Dalian shipyard manufacturing are large inline, two stroke, crosshead-type, low emission diesel engines for marine turbocharged and has a simple structure, adaptable, reliable, performance indicators higher and so on. Now widely used in coastal and ocean-going passenger and cargo ships and tankers, as the host.

    In summary, since the liberation, our diesel engine industry received a great deal of development. Diesel has been widely applied in automobiles, tractors, railway locomotives, ocean-going vessels, inland communication, irrigation and drainage machinery, engineering machinery, mining machinery, military vehicles, military ships and some power plants, etc., in our agriculture, industry, transportation and national defense construction, play an increasing role. However, we must see the current situation of China diesel engine industry, it can not meet the needs of the four modernizations, but current production of diesel engine performance of China and foreign countries compared to the production of diesel engine technology level there

    is a large gap. In order to narrow the gap, China since 1978, from Switzerland, France, West Germany, Denmark and Japan, the company introduced 17 Series 67 diesel engine production patent. This undoubtedly improve our science and technology and industrial manufacturing level, to accelerate the development of industries making machines and narrow the gap with foreign countries, has important significance. In order to catch up with international advanced level as quickly as possible, we must actively promote the reform of enterprise technology, closely rely on the scientific and technological progress and rational technology policy, organization of scientific and technological forces to carry out major issues of development, research, special attention should be paid the basic theory and applied research work, to do product series, generalization and standardization work to continuously improve the quality of strict products also make imported products should be seriously advanced technology digestion, absorption, migration and innovation of science and technology research.

Second, the layout engine in the ship

(A) low-speed large diesel engine layout

    Low-speed large-scale marine diesel engine as the host and promote the shaft is driven directly connected to the propeller, as shown below. Diesel power given by the middle of the propeller shaft and propeller shaft transmission, so that by rotating propeller thrust bearing thrust the ship forward or backward. Its layout is simple, usually only installed on each vessel a host.

(B)In the arrangement of high-speed diesel engine

    Medium and high engine speed is higher because, generally can not use a direct connection with the propeller shaft, but must advance through reduction gear box and shaft. Use, high-speed diesel engine as a host should select the best propeller speed, Er Shi promote maximum efficiency. This makes it possible to use less power to achieve the same speed, saving fuel costs. Use of high-speed diesel engines, in addition to single axis may be used 2 to 4 diesel engine through reduction gear box and a propeller shaft connection, it has the following forms:

    Single Single Two-plane uniaxial

    Three-axis machine Four-axis

    This arrangement can be achieved using a large power plant, while for large ships. For example, each engine cylinder 1100kW, 18-cylinder machines for the 19800kW, when two-plane uniaxial 39600kW, four-axis reaches 79000kW, but when using biaxial up 258400kwW. Therefore, it can be a large diesel engine power and low speed to compete, but also the power and steam turbine to compete. In order to reduce the fuel consumption rate of the device, also shown in the voyage through the reduction gear box with a power generator. While parked in the drive by a dedicated small diesel power generators. In addition, high-speed passenger ships and boats in the light, often using multi-axis multi-machine layout, as shown. In order to reduce the fuel consumption rate of the device, also shown in the navigation through reducing gear box with a power generator. While parked in the drive by a dedicated small diesel power generators. In addition, high-speed passenger ships and boats in the light, often using multi-axis multi-machine layout, as shown. One of the most commonly used for the Dual-axis, 3 axis and four-four-axis machines. This multi-axis machines more flexible layout, easy to manipulate, not single-axis and multi-machine synchronization car. There are several forms:

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