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1、Lesson 7 Starting Air System第 7 课 起动空气系统1. Diesel engines are started by supplying compressed air into the cylinders in the appropriate sequence for the required direction. A supply of compressed air is stored in air reservoirs or bottles or receivers at pressures about 30 or 40 bar ready for immedi
2、ate use. Up to 12 starts are possible with the stored quantity of compressed air. The starting air system usually has interlocks to prevent starting if anything is not in order柴油机是按所需方向, 以适当顺序向各缸通入压缩空气起动的。所供压缩空气以 3040bar 的压力存于气罐或气瓶内, 随时可用。所储存的压缩空气量可进行多达 12 次的起动。起动空气系统通常装有连锁装置, 若其他设备没准备好, 则不允许柴油机起动。2
3、. Compressed air is supplied by air compressors to the air receivers. The compressed air is then supplied by a large bore pipe to a remote operating non-return or automatic valve and then to the cylinder air start valve. Opening of the cylinder air start valve will admit compressed air into the cyli
4、nder. The opening of the cylinder valve and the remote operating valve is controlled by a pilot air system. Each cylinder air start valve is opened when the piston is just past TDC and closed just before the exhaust valve opens. There is always more than one air start valve open, which ensures that
5、the engine will start in any position.压缩空气由空压机提供给空气瓶。压缩空气通过大口径管道进入遥控操作的止回阀或自动阀, 进而到达气缸起动阀。气缸起动阀开启, 空气进入气缸。气缸起动阀及自动遥控阀由控制空气系统控制。每个气缸起动阀在(活塞) 经过上止点后立即开启 , 在排气口适当开启前关闭。通常至少有一个及以上的空气启动阀处于开启状态, 来确保主机能够在任何位置进行启动。3. The pilot air is drawn from the large pipe and passes to a pilot air control valve which s
6、operated by the engine air start lever. When the air start lever is operated, a supply of pilot air enables the remote valve to open. Pilot air for the appropriate direction of operation is also supplied to an air distributor. This device is usually driven by the engine camshaft and supplies pilot a
7、ir to the control cylinders of the cylinder air start valves. The pilot air is then supplied in the appropriate sequence for the direction of operation required. The cylinder air start valves are held closed by springs when not in use and opened by the pilot air enabling the compressed air direct fr
8、om the receivers to enter the engine cylinder. Starting air is shut off from the engine as soon as sufficient starting speed has been reached; fuel is then applied and the engine speed increased.控制空气来自主空气管并通入由柴油机起动操纵杆控制的起动控制阀。当操作起动手柄时, 控制空气使控制导阀手动开启或(当驾驶台安装控制系统时) 靠气动液压缸开启。控制空气也通入空气分配器。空气分配器通常由柴油机凸轮轴
9、驱动, 它将控制空气通入气缸起动阀。此控制空气按所需运转方向以恰当的顺序通入。当不用气缸起动阀时靠弹簧保持关闭。当它由控制空气打开时, 压缩空气便直接从空气瓶进入气缸。一旦达到足够的启动转速, 主机将切断启动空气, 供入燃油使主机的转速增加。4. An interlock in the remote operating valve line stops the valve opening when the engine turning gear is engaged. The remote operating valve prevents the return of air which has
10、 been further compressed by the engine into the system.遥控阀管线中的连锁装置在盘车机没脱开时，可防止阀开启。遥控阀可防止发动机(活塞)进一步压缩的空气回流进人(空气) 系统。5.A main engine must be capable of starting from any position and it is normal to have starting valves in each cylinder. Multi-cylinder Vee type engines may only require starting valves
11、 to be fitted to one bank of cylinders.主机必须可以从任何的曲轴位置都能启动，通常每缸都有启动阀。多缸 V 型柴油机可能只儒要在单列气缸上安装启动阀。6. Air start explosions occur during a start, when oil, which can accumulate in the air start receivers or on the surface of the start air lines, becomes entrained with high pressure air in the air start ma
12、nifold and is ignited. Regular maintenance work should be done and safety precautions should be taken to prevent such an occurrence.当聚集在启动空气瓶或启动空气管路表面的油与启动空气主管的高压空气混合并点燃时，启动期间就会发生爆炸。应当定期维护并采取安全预防措施防止此类事故发生。7. Lubricating oil from the compressor will under normal operation pass along the air lines an
13、d deposit on them. In the event of a cylinder air starting valve leaking, hot gases would pass into the air pipes and ignite the lubricating oil.（Checks must be made that cylinder starting air valves do not leak. These can be carried out while the engine is running by feeling the temperature of the
14、air pipe adjacent to the valve .） If starting air is supplied to the engine this would further feed the fire and could lead to an explosion in the pipelines. In order to prevent such an occurrence, cylinder starting valves should be properly maintained and the pipelines regularly drained. Also oil d
15、ischarged from compressors should be kept to a minimum, by careful maintenance.滑油从压缩机出来流经空气管路, 并沉积在内。在气缸起动阀万一泄漏时, 高温燃气便进入空气管, 点燃滑油。此时, 如果起动空气通入柴油机, 将加剧燃烧, 导致空气管路爆炸。为了防止此类事故的发生, 气缸起动阀应妥善保养并对管路定期放残。同时, 应通过细心保养, 使空压机排出的油保持在最小值。8. In an attempt to reduce the effects of an explosion, flame traps, relief
16、valves and bursting caps or discs are fitted to the pipelines. In addition an isolating non-return valve is fitted to the system. The loss of cooling water from an air compressor could lead to an overheated air discharge and possibly an explosion in the pipelines leading to the air reservoir. A high-temperature alarm or a fusible plug which will melt is used to guard against this possibility.为尽量减小爆炸的影响, 管系内需安装阻焰器、安全阀、防爆帽或防爆片。此外, 系统内还要安装一个独立的止回阀(自动阀 )以防压缩空气进一步进入系统。空压机冷却水不足会导致排出的空气过热,
