发动机engine
螺旋形的spiral
化油器carburetor
挖掘机digger
润滑lubricate
推土机bulldozer
销pin
车架frame
保险杠bumper
惰轮idler
进气行程inlet stroke
连杆connecting rod
压缩比compression ratio
导向轴承spigot bearing
铸铁cast-iron
Principles of Engine Operation
发动机工作原理
Internal-combustion engines are those that burn their fuel inside the engine. Those that burn gasoline are known as gasoline engines. Other types of internal-combustion engines burn heavier oils or fuels. Of these types the diesel engine has come into the widest use.
内燃机指那些在内部燃烧燃油的发动机。燃烧汽油的发动机成为汽油机。其它类型的内燃机燃烧重油，其中柴油机使用最广泛。
All engines convert one form of energy into another. Internal-combustion engines convert the chemical energy stored in their fuels into heat energy during the burning part of their operation . The heat energy is converted into mechanical energy by the expansion of gases against pistons attached to crankshafts.
发动机将一种能量转变成另一种形式。在工作过程中，内燃机将燃料中的化学能转变成热能。热能在气体膨胀过程中转变成机械能，作用在与曲轴相连的活塞上。
To transfer the energy resulting from this expansion into useful work, a construction such as shown in Fig. 1-1 is used.
为了在把膨胀中的机械能转变成有效功，一种如图1-1的结构得以应用。
The force exerted on the piston is transmitted through the connecting rod to the crankshaft that is made to revolve, turning through one-half of a revolution as the piston moves downward. Attached to the crankshaft is a flywheel, which stores up energy. The momentum of the flywheel carries the piston through the balance of its motion until it receives another power impulses. In this way the reciprocating motion of the piston is transformed into a rotary motion at the crankshaft.
作用在活塞上的力通过连杆传递给曲轴，使其转动，当活塞下行时转动半周。飞轮与活塞相连，它可以储存能量。它的动力驱动夸过其运动平衡点，直到活塞接受到下一次动力。如此，活塞的往复运动就转变成曲轴的转动。
The number of strokes of the piston required to complete the cycle varies with the type of engine. The cycle is generally extended through four strokes of the piston or two revolutions of the crankshaft. This is called a four-stroke-cycle or a four-cycle engine.
可以用活塞完成循环所需的冲程数目来区分发动机。通常，一个工作循环分为活塞的四个行程或曲轴转动两全的发动机称为四冲程发动机。
In the four-stroke-cycle engine, the four strokes are named suction, compression, power and exhaust.
在四冲程发动机中，这四个冲程叫做进气、压缩、作功和排气。
Suction Stroke. During this stroke, the crankshaft moves the piston downward. Fresh mixture is sucked into the cylinder through the open inlet valve.
进气冲程：在这个冲程中，曲轴转动使活塞下行。在进气门打开时，新鲜空气被吸入气缸。
The force exerted on the piston is transmitted through the connecting rod to the crankshaft that is made to revolve, turning through one-half of a revolution as the piston moves downward. Attached to the crankshaft is a flywheel, which stores up energy. The momentum of the flywheel carries the piston through the balance of its motion until it receives another power impulses. In this way the reciprocating motion of the piston is transformed into a rotary motion at the crankshaft
Bulldozer is a earth moving machine, which is pendant attachment mounted on crawler and wheel tractors. In laying a road bed bulldozers are employed to strip off the vegetation covering, remove bushes, stumps and small trees, dig and transport soil from cuts to a pile, build fills, push soil from cuts to spoil banks, move soit when shaping earth bed on hillside, grade and level soil piled up by earth diggers, fill up trenches, ditches and pits, transport dirt to bridge abutments.
推土机是一个土方移动机械，它是在履带或轮式拖拉机上悬挂工作部件而成的。在铺筑路基时推土机被用来剥离植被、清除灌木、树桩和小树、挖土并将土从挖土处运到堆土处、填方、推土至弃土堆、在山坡上修筑路基时推土、平整挖掘机堆积的土堆、填平沟、渠和凹坑、运淤泥到桥墩处。
The chassis in general is equipped with a I-beam construction front axle. For a good chassis design and for its good performances, it must have fast, pickup, strength, safety, durability, dependability, ease of control, quietness, speed, power, accessibility, economy of operation, low center of gravity, stability, load clearance, braking ability, good springing, simplicity of lubrication etc.
he grader blade is attached to the blade circle; this circle is turned by a hydraulic motor via a worm and wheel drive unit. The circle is attached to the circle frame (drawbar).The circle frame is mounted to the front of the grader frame by means of swivel ball joint. Mounted on the back of the grader blade is a scarifier (ripper) with 6 scarifier teeth. It is possible to scarify in forward or reverse direction.
平地机刮刀安装在环形刀架上，刀架可以在液压马达通过涡轮蜗杆驱动下转动。刀盘安装在刀盘架上。刀架通过回转球铰固定在车架上。在刮刀的后面是一个带有6个松土齿的松土耙。它可以向前向后翻土。
The type of fuel available for use in diesel engine varies from highly volatile jet fuel and kerosene to the heavier furnace oil. Automobile engines are capable of burning a wide range of fuel between these two extremes. How well a diesel' engine can operate with different types of fuel is dependent upon engine operation conditions, as well as fuel characteristic
燃料类型可用于柴油发动机不同高度挥发性喷气燃料和煤油炉油的重。汽车引擎能燃烧多种燃料这两极之间。如何以及柴油发动机可以操作的不同类型的燃料是取决于发动机的运行条件，以及燃料特性
In modern automobile the lubrication system is classified as" pressure" or" splash'' although various combination of these two systems are used. Most passenger cars use the pressure system in which the oil is forced under pressure by a gear pump to most of the various rotating or reciprocating parts.