新版轮机英语UNIT11_a leap in techology for marine engines.ppt

Lesson 11 A Leap in Technology for Marine Engines• The most up-to-date(最近的，新式的） common rail（共轨技术） diesel technology is reliable, clean, economic, durable-and in the MAN Group（系列） it is now available for the engine of a small truck（筒形活塞） up to a large marine diesel.Technology• In common rail（共轨） diesel engines fuel is injected into all the cylinders via a “common rail“. • The generation of pressure and injection of fuel are not interconnected （使互相连接） in the common rail system. • Unlike in conventional systems, the injection pressure is independent of the engine speed. • Thus there is always（始终，永远） full pressure available. • The fuel is first stored in the fuel line and then, when a signal is given by the engine controls to the magnetic valves, injected into the cylinders. • This creates an extremely（非常的） fine fuel-air mixture which burns particularly efficiently.Reliability• Reliability（可靠性） and durability（ 耐用性） are an absolute necessity（必 要性，需要） in engines on sea-going vessels. • For this reason the new MAN B＆W Diesel common rail engine is especially （特别，尤其） designed for reliability. • The whole systems, including the electronic controls is fully redundant（ 冗余的）, i.e. every major function has a back-up（备份）. • Thus there are at least two high- pressure pumps to every machine, ensuring that the pressure necessary for fuel injection is available, even if onepump fails. • Unlike in most other common rail engines, the MAN injection system is based on conventional pressure-controlled injection. • In conventional stroke controlled systems, which function with pilot（提 前） and post-injections, there is a permanently high pressure of 1,600 bar, for example, at the needle seat near the combustion chamber. 【4】• In the MAN B＆W system, the pressure on the valve needle is released by means of the solenoid valve（电磁阀）, which is located away from the cylinder head, at the common rail accumulator（蓄压器， 蓄能器）. • As a result there is not permanently（永 久的） full pressure on the valve needle seat next to the combustion chamber and the electronic components（成分，元件） are protected.Advantages• By means of CR injection it is possible to control combustion precisely and flexibly（灵活性） within the operating range（范围，行列） of the engine. • This lowers the fuel consumption. Optimized （使最优化） fuel injection also diminishes （减少） combustion noise and the exhaust mission of pollutants. • Optimal，pollute• Thus soot（烟灰，煤烟） emission（ 散发，烟雾排放） at part loads is for example reduced to a level below the visibility limit. • This is becoming increasingly significant in marine applications as the pollutant emission limits are becoming increasingly stringent（ 严厉的） worldwide. • In particular, start-up soot should be avoided. • Common rail technology proves a particular advantage at low speeds and when operating condition change fast, for example in suction dredgers（挖泥船） or in cruise(班轮） liners traveling very slowly in coastal（海岸的，沿海的） waters.New marine engines• In June, 2006, MAN B＆W Diesel introduced two new engines S35ME-B and S40ME-B.• Based on simple and well-proven diesel technology, the S35ME-B and the S40ME-B provide an engine that is geared to（使适合） market requirements• for electronic control（电子控制）, size reduction, fuel economy, high power, reliability, longer time between overhauls（检修，大修）, lower propeller speed and better vessel maneuverability.• Advanced, user-friendly（用户友好的） , electronic control of fuel injection provide owners with an efficient way for emission control（排放控制） to meet current（现在的，通用的） and future environmental requirements, • as well as offer full control of energy management, giving fuel economy that is second to none in its class down to 170g／kW·h.• Like on the larger ME-engine, the Alpha Lubricator is standard, with the benefit （受益） of very low total lube oil consumption.• The advanced electronic user interface （界面） is easy to handle（操纵） and monitor（监控） performance（性能） allows precise（精确的） adjustments of the economy-vital variables of lubricating oil and fuel.• The electronic fuel injection management system of the S35ME-B and the S40ME-B gives optimal engine performance in powerful, • economic, weight-saving and future- oriented（导向的） diesel engines ensuring that they will remain market leaders for decades to come.• S35ME-B• Bore 350 mm• Stroke 1,550 mm• MEP 21 bar• Speed 167 r／min• Mean piston speed 8.6 m／s• Power 870 kW／cyl• SFOC 171-176 g／kW·h• S40ME-B• Bore 400 mm • Stroke 1,770mm• MEP 21bar • Speed 146 r／min• Mean piston speed 8.6 m／s• Power 1,135 kW／cyl• SFOC 170-175 g／kW·h。