Technological development of marine high-power diesel engines and analysis of domestic industry status quo
Author: Chen Hui Source: China Water Transport Magazine Date: June 12, 2009 Clicks: 1304
1. Introduction
At present, my country's shipbuilding industry has achieved rapid development. Ship exports have accounted for more than 80% of the total shipbuilding volume. Ships are exported to more than 100 countries and regions, making it one of the top companies in the world. A major ship exporting country. According to statistics reported by the China Shipbuilding Industry Association, in the first half of 2008, the country's completed shipbuilding volume was 10.24 million deadweight tons, and the number of ship orders in hand was 192.17 million deadweight tons; according to the statistics of the world's total shipbuilding volume by the British Clarkson Research Company, my country's completed shipbuilding The world market share of volume, new ship orders undertaken and ship orders on hand accounted for 26%, 39% and 34% respectively. my country's status as a world shipbuilding power continues to be consolidated. However, our country's shipbuilding industry is large but not strong, and the development of marine supporting equipment is seriously lagging behind. Among them, the marine diesel engine is one of the key supporting equipment of the ship and the "heart" of the ship. It accounts for 10 to 15 of the total cost of ship construction. However, the diesel engines used in ships built in my country are mainly original engines purchased directly from abroad or products produced with imported licenses from abroad. According to Chinese customs statistics, in 2007, the import of marine diesel engines was US$1.079 billion, an increase of 76% over the previous year. Taking low-speed machines as an example, although output is increasing year by year, the gap relative to demand is increasing. The situation of medium-speed engines for ocean-going ships is not optimistic either. 70% of the shipments are imported products from abroad, and the remaining 30% are basically products manufactured by domestic enterprises with production licenses.
In recent years, the shipping industry has continued to prosper and the tonnage of ship manufacturing has continued to rise, resulting in a global supply shortage of high-power marine diesel engines. However, the proportion of Chinese-made main engines for my country's marine diesel engines continues to decline, and the local loading rate is only about 40%. For example, some large container ships and ultra-large product oil tankers are equipped with imported main engines. Therefore, in order to make my country's shipbuilding industry develop well and quickly, it is urgent to accelerate the development of my country's ship diesel engines and form a complete and advanced ship supporting industry chain. This article analyzes the current status and development trends of domestic and foreign marine high-power diesel engine technology, points out the problems faced by my country's marine high-power diesel engine industry, and aims to provide reference for the development of my country's marine high-power diesel engine industry.
2. Technical Development of Marine High-Power Diesel Engines
At present, transportation ships, especially ocean-going ships, are developing in the direction of large-scale, automated, intelligent, etc., and large-scale marine diesel engines are also emerging one after another. Large-bore, intelligent model with high power, low emissions, low fuel consumption and high reliability. In recent years, the world's major marine diesel engine companies have successively launched new marine diesel engines, all of which have adopted a large number of new technologies and research results, such as combustion and emission control technology, modular design technology, high-efficiency turbocharging technology, high-pressure** *Rail fuel injection technology, electronic control technology, etc.
1. Improving the average effective pressure and unit power
Continuously increasing the average effective pressure and unit power, and reducing the specific weight and volume are the main goals that marine high-power diesel engines have long pursued. At present, the average effective pressure of high-power marine diesel engines continues to increase, but the maximum combustion pressure also increases, affecting the reliability and life of the diesel engine. Therefore, the current single-machine power is mainly increased by enlarging the bore and increasing the number of cylinders. Another option to increase the power of a single engine is to develop a V-shaped engine. Currently, there is no technical problem with low-speed diesel engines using V-shaped 16-cylinder or V-shaped 18-cylinder engines, which can meet the requirement of a single engine power of 92,000kW. Since the average effective pressure is very high, even if it operates according to the propeller characteristics, it is difficult to guarantee the performance under low operating conditions. Therefore, various measures must be taken to optimize the performance of the diesel engine in all operating conditions. Currently, commonly used methods are to adopt measures such as high-working-condition bleed, low-working-condition intake and exhaust bypass, or STC (successive supercharging).
2. Combustion and Emission Control
Emission control measures for marine diesel engines can be divided into internal control and external control.
In-machine control refers to reducing pollutant emissions before the combustible mixture is burned. The main measures include: using in-machine and external exhaust gas recirculation technology (EGR); optimizing diesel engine structural parameters and operating parameters; using wet NOx reduction technology ;Add fuel additives, etc. Off-machine control refers to further reducing emissions based on on-machine control, such as using selective catalytic reduction technology (SCR), exhaust gas scrubbing, etc. Both internal and external measures can be used to make marine diesel engine emissions comply with standards. However, the cost of external measures to achieve the same effect is about 4 to 5 times that of internal measures. Therefore, most marine diesel engines still use internal control methods. And combined with automatic monitoring and control technology.
Major foreign marine diesel engine R&D and production institutions and companies have carried out research on combustion and emission control technologies. In recent years, electronically controlled rail injection technology has been well applied in marine diesel engines. It can enable the diesel engine to inject fuel into the cylinder with optimized injection advance angle and injection pressure under different load conditions, which not only reduces Improves fuel consumption and reduces NOx emissions. In addition, high supercharging technology, high-efficiency combustion technology and electronic control technology, which are important technologies for combustion and emission control technology, have also been widely used.
3． Intelligent electronic control technology
In August 2005, the world's first seven-cylinder intelligent (7RTflex58T-B) marine engine was delivered to Dalian Marine Diesel Engine Factory. The maximum output power is 15260kW. The engine adopts At that time, the world's most advanced WECS9520 electronic control system controlled fuel injection, exhaust valve opening and closing, main engine starting and reversing, replacing traditional hydraulic and pneumatic controls to make the diesel engine burn more fully. Due to the use of computer control, this model eliminates the camshaft system, making the operation simpler and more convenient, and effectively reduces the weight of the host. It is reliable, flexible and highly compatible. As ships are increasingly larger and more intelligent, intelligence has become an inevitable trend in the development of marine diesel engines.
4. Reliability technology
The large-scale and high-index marine diesel engines have brought higher requirements to diesel engine parts (or modular parts), especially the working conditions of combustion chamber-related parts and moving friction parts. Its reliability has received much attention, and the research focus includes key technologies such as reliability design, friction and wear, and fault diagnosis.
5. Overall design technology of diesel engine
Marine diesel engines should also have excellent overall comprehensive performance and adaptability under various working conditions. To this end, on the basis of maintaining the reliability, economy, low emissions and easy maintenance of the model, we focus on optimizing the overall structure of the diesel engine to make it more compact, smaller in size and lighter in weight. The main key Technologies include: modular design technology, 3D-CAD design analysis, structure and performance optimization simulation technology, etc.
3. Current status of my country’s marine high-power diesel engine industry
1. Marine low-speed diesel engines
High-power low-speed diesel engines are mainly used in large ocean-going ships such as bulk carriers, oil tankers, and container ships. Most of them are two-stroke diesel engines. Judging from the global market share of low-speed engine products, on ships with a capacity of more than 2,000 tons with low-speed engines as main engines, the low-speed engine products of MAN-B&W and WARTSILA-SULZER account for more than 90% of the world's share, with a cylinder diameter of 260-1080mm. , power 1600-97300kW. In recent years, MAN-B&W Company has developed rapidly by transferring production licenses to diesel engine manufacturers in Japan, South Korea and China. In the field of low-speed marine diesel engines in my country, all models of MAN Bamp; W and Wartsila are currently imported. For example, Hudong Heavy Machinery Co., Ltd., Dalian Marine Diesel Engine Factory, Yichang Marine Diesel Engine Factory, through the Danish Bamp; W company and Finnish WARTSILA- SULZER Company introduces patented technology to produce low-speed and high-power marine diesel engines, mainly for dry bulk carriers, extra-large oil tankers, container carriers, etc. produced by several major domestic shipyards.
In recent years, my country's marine main engine production has developed rapidly. Dalian Marine Diesel Engine Factory's MAN Bamp; W7S60MC-C, Hudong Heavy Machinery's MAN Bamp; W 6K80MC-C, 7S80MC and Yichang Shipbuilding The diesel engine factory's Sulzer RT-flex58T-B intelligent marine low-speed and high-power diesel engines all represent the current international advanced level. However, there is still a big gap between my country's machinery manufacturing enterprises and Hyundai Heavy Industries, HSD, Mitsui Shipbuilding, Kawasaki Heavy Industries and other machinery manufacturing enterprises in South Korea and Japan, and the comprehensive competitiveness of the enterprises is still weak. Mainly due to insufficient capital investment, machine-building companies have not planned and invested simultaneously with shipbuilding companies, production capacity is relatively lagging, production scale is not large, and output is not high; in addition, there are weak research and development capabilities, small production sites, and the production scale of domestic supporting companies Due to problems such as small size and poor self-control ability, it cannot meet the needs of large-scale and high-efficiency production.
2. Marine medium and high speed diesel engines
Marine medium and high speed diesel engines are mainly used on various types of inland river ships, offshore ships, engineering ships and ships. The world's medium-speed diesel engine manufacturers include Sulzer, Wartsila, Mark, MAN B&W, MTU, Yanmar, Caterpillar, etc. Among them, MAN B&W and W?rtsil?, the two major diesel engine companies, account for the world's main engine output. More than 75%. High-speed machines are mainly produced by MTU, DeutzMWM, Caterpiliar and other companies.
my country's high-power medium-speed diesel engines have gone through the process of introduction, self-development, then introduction and localization, digestion, absorption and improvement. In recent years, the technical level of my country's marine medium and high-speed diesel engines has made great progress. Through technology introduction, we have not only mastered the advanced technology of foreign diesel engines, but also made corresponding technical improvements to our country's diesel engine manufacturers, and supplemented and updated a number of key process equipment. , accumulated experience in manufacturing advanced diesel engines. While digesting and absorbing advanced foreign technologies, some new generation marine diesel engines have also been developed. The design, research and production system is beginning to take shape, but the overall level is not high, and the manufacturing process of key components is backward and cannot reach high quality levels. At present, 70% of the medium-speed engines installed on ocean-going ships manufactured in my country are directly purchased from imported original engines, and the remaining 30% are almost all products manufactured with foreign licensed technologies. The technology relies on foreign countries and has no independent intellectual property rights.
IV. Outlook
The rapid development of marine diesel engine technology puts China's marine diesel engine industry, which is at a competitive disadvantage in the technical field, facing severe challenges. Strengthening strength, developing independent brands, expanding localized manufacturing capabilities, and increasing shipping rates are urgent issues that need to be solved in my country's marine diesel engine industry. The development of my country's marine diesel engines must adhere to the path of localized technological innovation of "introduction-digestion-absorption-reinnovation" and accelerate the development of marine diesel engines and their supporting industry chains. The focus of the development of marine medium-speed engine products is to optimize the manufacturing process, improve product design capabilities, break through key technologies, and develop high-level Chinese brands with independent intellectual property rights on the basis of strengthening the digestion and absorption of imported production license diesel engine technologies. It will gradually realize the serialization of its own brand of medium-speed diesel engines, improve its competitiveness in the international market, and change the current situation in which imported engines dominate the civil ship medium-speed engine market in my country. Strengthen the introduction of localized research and development of key components of medium and low-speed diesel engines, focus on cultivating and supporting diesel engine second-wheel supporting enterprises with strong technology and production capabilities, and form the ability to independently support domestic marine diesel engines.