专业汽车英语
专业英语——Engine Terms（发念头术语） Engine Terms（发念头术语）
TDC(top dead center) ― the position of the crank and piston when the piston is farther away from the crankshaft.
TDC (上止点) - 当活塞离曲轴最远时，曲柄和活塞的地位。
BDC (bottom dead center) ― the position of the crank and piston when the piston is nearest to the crankshaft.
BDC (下止点) - 当活塞离曲轴比来时，曲柄和活塞的地位。
stroke ― the distance between BDC and TDC; stroke is controlled by the crankshaft.
行程 - 下止点和上止点之间的距离；行程由曲轴操纵。
bore ― the internal diameter of the cylinder.急忙忙
缸径 - 汽缸的内径。
swept volume ― the volume between TDC and BDC.
有效容积 - 上止点和下止点之间的体积。
engine capacity ― this is the swept volume of all the cylinders, e.g. a four-cylinder engine h
aving a capacity of two liters (2000 cm3)
has a cylinder swept volume of 500 cm3.
发念头排量 - 这是全部汽缸的有效容积，例如一台排量为两公升(2000 cm3)的4个汽缸的发念头每一个汽缸的有效容积为500 cm3。
clearance volume ― the volume of the space above the piston when it is at TDC.
间隙容积 – 当活塞位于上止点时，活塞顶上面的气缸空间。
compression ratio = (swept vol + clearance vol)/(clearance vol)
紧缩比 = ( 有效容积 + 间隙容积 ) / ( 间隙容积 )
two-stroke ― a power stroke every revolution of the crank.
深表歉意 二冲程 – 曲柄扭转一圈作功一次。
four-stroke ― a power stroke every other revolution of the crank.
四冲程 - 曲柄扭转两圈作功一次。
汽车专业英语——Valve System（配气机构）Valve System（配气机构）
Inlet Valve Timing（进气配气准时）
拔牙记>个人小结100字 If the inlet valve opened at TDC of the intake stroke and clod at BDC of that stroke, it w
ould have a duration of 180°.It would have remained open for half of a complete 360° revolution, or 180°. However, it takes some time for the valve to open to its full position. It also takes time for it to clo tightly. Therefore the valve is opened before TDC (BTDC) and clod after BDC (ABDC).雪域豹影
假如进口门在进气行程的上止点打开同时在此次行程的下止点封闭，它将有180°的开度。气门在180°转角内完全打开。然而气门达到全开地位须要一准时刻，完全封闭也须要一准时刻。是以阀门在上止点(BTDC)之前被打开，鄙人止点(ABDC)之后封闭。
Exhaust Valve Timing（排气配气准时）
If the exhaust valve opened at BDC at the beginning of the exhaust stroke and clod at TDC at the end of the exhaust stroke, it would have a duration of 180°. But like the inlet valve, the exhaust valve needs time to reach the full-open position, It also needs time to reach the full-clod position. So the exhaust valve opens before BDC and clos after TDC.
假如排气门在排气行程的下止点打开同时在此次行程的上止点封闭，它将有180°的连续。然则像进气门一样，排气门须要时刻达到充分打开和封闭的地位。是以排气门鄙人止点之
前打开，在上止点之后封闭。
Valve Overlap（气门重叠）
The intake opens at 17° BTDC and the exhaust clos at 17° ATDC. Thus, for a period of 34°, both of the valves are open: (17° + 17° =34°). This period of time is known as valve overlap. The closing of the exhaust valve laps over the opening of the intake valve. During this time, the first of the new mixture pushes the last of the burned gas out the exhaust valve. Valve overlap is held to a minimum on turbo-charged engines. This prevents the intake charge from being blown out the exhaust.
进气门在上止点前17°打开，排气门在上止点后17°封闭。 是以，有34°的一段时代，两个阀门差不多上开的：(17°+ 17°= 34°)。这时代被称为气门重叠。排气门的封闭和进气门的开启重叠。在那个时刻，新的混淆气推动燃烧后的废气从排气门排出。在涡轮增压发念头上气门重叠角被保持在一个最小值。这就防止废气倒流入进气管。
Valve Operation（配气机构）
To coordinate the four-stroke cycle, a group of parts called the valve train opens and clos the valves (moves them down and up, respectively). The valve movements mus
t take place at exactly the right moments. The opening of each valve is controlled by a camshaft.
那些打开和封闭气门的气门传动是为了调和四冲程的工作轮回(使他们各自高低移动)。这些阀门活动必须正好在合适的时刻进行。每个阀门的开启由凸轮轴带动
Overhead camshaft (OHC) valve train（顶置凸轮轴气阀传动）
The cam is an egg-shaped piece of metal on a shaft that rotates in coordination with the crankshaft. The metal shaft, called the camshaft, typically has individual cams for each valve in the engine. As the camshaft rotates, the lobe, or high spot of the cam, pushes against parts connected to the stem of the valve. This action forces the valve to move downward. This action could open an inlet valve for an intake stroke, or open an exhaust valve for an exhaust stroke.
凸轮是一在轴上的蛋形的金属，经由过程曲轴调和扭转。那金属轴叫凸轮轴，在发念头里的每个气门一样有各自的凸轮。当凸轮轴扭转时，凸轮凸起的或者高点的地位，推动气门座。这行动强迫阀门向下移动。这过程能使进气门在进气行程打开，或者排气门在排气行程打开。
As the camshaft continues to rotate, the high spot moves way from the valve mechanism. As this occurs, valve springs pull the valve tightly clod against its opening, called the valve at.
因为凸轮轴连续扭转，凸轮轴上的凸起部分别开气门装配。当这产生时，气门弹簧紧紧地封闭气门口，叫做气门座。
Valves in modern car engines are located in the cylinder head at the top of the engine. This is known as an overhead valve (OHV) configuration. In addition, when the camshaft is located over the cylinder head, the arrangement is known as an overhead camshaft (OHC) design. Some high-performance engines have two parate camshafts, one for each t of inlet and exhaust valves. The engines are known as dual overhead camshaft (DOHC) engines.
现代汽车发念头里的阀门位于发念头顶上的汽缸盖。这被称为顶置气门(OHV)构造。别的，当凸轮轴位于汽缸盖上面时，这种方法被称为是顶置凸轮轴(OHC)构造。一些高机能发念头有两个零丁的凸轮轴，分别负责开关进气门和排气门。这些发念头被称为双顶置凸轮轴(DOHC)发念头。
Push-rod valve train（推杆气阀传动）
The camshaft also can be located in the lower part of the engine, within the engine block. To transfer the motion of the cam upward to the valve, additional parts are needed.
凸轮轴也装在发念头底部的气缸体内。为了将凸轮的活动传给气门须要一些从属装配。In this arrangement, the cam lobes push against round metal cylinders called cam follower. As the lobe of the cam comes up under the cam follower, it pushes the cam follower upward (away from the camshaft). The cam follower rides against a push rod, which pushes against a rocker arm. The rocker arm pivots on a shaft through its center. As one side of the rocker arm moves up, the other side moves down, just like a esaw. The downward-moving side of the rocker arm pushes on the valve stem to open the valve.
在这种安排中，凸轮凸角推动凸轮挺杆。当凸轮的凸角在凸轮挺杆下显现时，它推动凸轮挺杆向上活动(分开凸轮轴)。凸轮挺杆推动操纵摇臂的推杆。摇臂以经由过程它的中间为轴而扭转。当摇臂的一侧上升，其另一侧降低，正如一块跷跷板一样。摇臂向下移动的那一边推动气门杆以打开气门。
Becau a push-rod valve train has additional parts, it is more difficult to run at high spee
ds. Push-rod engines typically run at slower speeds and, conquently, produce less horpower than overhead-camshaft designs of equal size. (Remember, power is the rate at which work is done.)
因为推杆气阀传动有别的的部分，因此专门难以高速运转。推杆发念头一样在低速运转，从而产生比雷同大年夜小的顶置凸轮轴较少功率。(记住，功率反应了工作才能。)
Valve Clearance（气门间隙）
When the engine runs in compression stroke and power stroke, the valves must clo tightly on their ats to produce a gas-tight al and thus prevent the gas escaping from the combustion chamber. If the valves do not clo fully the engine will not develop full power. Also the valve heads will be liable to be burnt by the passing hot gas, and there is the likelihood of the piston crown touching an open valve, which can riously damage the engine.
当发念头处于紧缩行程和做功行程时，阀门必须紧紧地封闭以产生一个不透气的气封，以防止气体逃离燃烧室。假如阀门不完全封闭，发念头将不克不及发挥全部动力。此外气门头易于被经由过程的热气体燃烧，这有可能使活塞频繁冲击打开的气门，使发念头严峻破
坏。
So that the valves can clo fully some clearance is needed in the operating mechanism. This means that the operating mechanism must be able to move sufficiently far enough away from the valve to allow the valves to be fully clod against its at by the valve spring. However, if the clearance is t too great this will cau a light metallic tapping noi.
因此阀门能完全封闭，气门间隙在操作机构内是必须的。这意味着操作机构必须离阀门足够远以许可阀门经由过程气门弹簧使其完全封闭。然则，假如间隙太大年夜，将引起金属轻敲的噪音。
Camshaft Drive Mechanism（凸轮轴驱念头构）
Each cam must revolve once during the four-stroke cycle to open a valve. A cycle, remember, corresponds with two revolutions of the crankshaft. Therefore, the camshaft must revolve at exactly half the speed of the crankshaft. This is accomplished with a 2:1 great ratio. A gear connected to the camshaft has twice the number of teeth as a gear connected to the crankshaft. The gears are linked in one of three ways:
决算报告
在四行程轮回时，每凸轮必须扭转打开一阀门。记住，一个轮回相当于曲轴扭转两次。是以，凸轮轴必须以曲轴正好一半的速度扭转。这用2：1的传动比完成。齿轮连接到凸轮轴的齿数是齿轮连接到曲轴的两倍。齿轮贯穿连接有三种方法：
（1）Belt drive（皮带传动）
水母的特点>我的幸福生活作文 A cog-type belt can be ud. Such belts are made of synthetic rubber and reinforced with internal steel or fiberglass strands. The belts have teeth, or slotted spaces to engage and drive teeth on gear wheels. A belt typically is ud on engines with overhead-cam valve trains.
齿型带能被应用。如许的带是由合成橡胶做成同时用内部的钢或者玻璃纤维绞合加强。皮带上有齿，或者槽以啮归同时驱动传动齿轮上的齿。皮带一样与顶置凸轮阀门传动一路被用在发念头上。
