英语翻译Valve GearThe valve gear provides timely admission of th

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英语翻译
Valve Gear
The valve gear provides timely admission of the fresh charge into the cylinders and exhaust of spent gases from them.The valves at definite moments open and close the intake and exhaust ports in the cylinder head,through which the cylinders communicate with the intake and exhaust manifold.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.There are several different arrangements of camshafts on engines.
Single overhead camshaft (SOHC)
This arrangement denotes an engine with one camshaft per head.So if it is an inline 4-cylinder or inline 6-cylinder engine,it will have one camshaft; if it is a V-6 or V-8,it will have two camshafts (one for each head).The camshaft actuates rocker camshaft that press down on the valves,opening them.Springs return the valves to their closed position.These springs have to be very strong because at high engine speeds,the valves are pushed down very quickly,and it is the springs that keep the valves in contact with the rocker arms.If the springs were not strong enough,the valves might come away from the rocker arms and snap back.This is an undesirable situation that would result in extra wear on the cams and rocker arms.
Double overhead camshaft (DOHC)
A double overhead cam engine has two camshafts per head,one for each set of inlet and exhaust valves.These engines are known as dual overhead camshaft (DOHC) engines.So inline engines have two camshafts,and V engines have four.Usually,double overhead cams are used on engines with four or more valves per cylinder -- a single camshaft simply cannot fit enough cam lobes to actuate all of those valves.
The camshaft must revolve at exactly half the speed of the crankshaft.This is accomplished with a 2:1 great ratio.The gears are linked in one of three ways:
(1)Belt drive
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 used on engines with overhead-cam valve trains.
(2)Chain drive
On some engines,a metal chain is used to connect the crankshaft and camshaft gears.Most push-rod engines and some OHC engines use this driving.
(3)Gear drive
The camshaft and crankshaft gears can be connected directly,or meshed.This type of operating linkage commonly is used on older six-cylinder,inline engines.
The valve gear is composed of timing gears,a camshaft,tappets,valves,spring with fasteners and valve guides.
1个回答 分类:英语 2014-11-06

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阀装置
阀门齿轮提供及时承认的新鲜收费进入气缸和尾气排放的气体从他们度过.阀门在明确的时刻开启和关闭和进排气港口缸盖,通过气缸与进、排气歧管.阀门在现代汽车发动机缸盖位于顶部的引擎.这就是所谓的开销阀(OHV)结构.有几种不同的发动机凸轮轴的安排.
单顶置凸轮轴(SOHC)
这样的安排表示引擎使用人均一个凸轮轴.所以,如果这是一个内联或内联6-cylinder四缸引擎,它会有一个凸轮轴;如果它是一个v -或v - 8,它将有两个凸轮轴(每一头).凸轮轴驱动型凸轮轴,摇臂向下按阀门,打开它们.弹簧阀返回他们关闭位置.这些弹簧必须非常强大,因为在高发动机转速,阀门被下推的非常的快,这是弹簧,保持阀门在与摇臂.如果弹簧不够牢固,阀门可能离摇臂和迅速反弹.这是一个不受欢迎的情况,会导致额外的穿cams及摇臂.
双顶置凸轮轴(DOHC)
双顶置凸轮引擎有两人均凸轮轴的,每一个组的进口和排气阀门.这些发动机被称为双顶置凸轮轴(DOHC)发动机.所以内联引擎有两个凸轮轴,和V引擎有四个.通常,双开销凸轮发动机上使用四个或更多的阀门每气缸——一个凸轮轴凸轮叶根本不能足够适合应用在所有这些阀门.
凸轮轴要围绕恰恰在一半的速度的曲轴.这是实现伟大的比例为2:1.齿轮有关的三种方式:
(1)带驱动
这样的带是由合成橡胶和强化内部钢或玻璃纤维绞合.皮带上有齿,或者槽空间,从事和驱动传动齿轮上的齿.皮带一般是用在发动机与overhead-cam阀门火车.
(2)传动链
在一些发动机,金属链被用来连结曲轴和凸轮轴齿轮.大多数推杆发动机和一些顶置凸轮轴发动机使用这个驱动.
(3)齿轮传动
凸轮轴和曲轴齿轮可直接连接,或者相啮合.这种类型的操作联动通常被用在老六缸,内联引擎.
阀门齿轮由定时齿轮,凸轮轴,挺杆,阀门,阀门弹簧紧固件及指导.
有几个地方有点问题,你再看看,
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