(新版)汽车专业英语课件：Starting System and Ignition System

1、汽车自动变速器构造与检修,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,*,Project 5 Starting System and Ignition System,1,2,Project 5 Starting System and Ignition System,掌握汽车启动系统、点火系统,的组成结构和工作过程,掌握系统主要部件的的专业术,语表达,知识目标,能读懂发动机启动系统、点火,系统的课文材料,能熟记启动马达、点火线圈、,点火器、一级和二级绕组等关键,零部件及其组成的相关专业词,汇、术语,能看图写出零件名称,;,能力目标,3,Task 1 Starting-motor system,1.New words and expressions,initiate iniieit vt.,开始、让,加入,minimum minimm n.,最低限度、最小量,adj.,最低的、最小的,atomize tmaiz v.,使分裂为原子、将,喷成雾状,cyclic saklk,sklk adj.,周期的、循环的、轮转的,adequate dikwit adj.,充分的、足够的、

2、适当的,momentum mumentm n.,动力、冲力,exert iz:t vt.,用,(,力,),、尽,(,力,),、施加,breakaway brek,we n.,脱离、摆脱,standstill stnd,stl n.,静止状态、停顿,peak pi:k n.,尖端、最高点、高峰,compensate kmpenseit vt.&vi.,补偿、报酬,prerequisite pri:rekwzt n.,先决条件、前提,知 识,准 备,4,1.New words and expressions,minimal miniml adj.,正式,最小的、极少的,ejection i,dekn n.,喷出,排出物,helical helikl adj.,螺旋状的,spline splain n.,齿条、止转楔、花键,vt.,用花键联接、开键槽,axially adv.,轴向方向,charge trd n.,电荷，,vt.,使充电,generator dn,ret n.,发电机,dead weight n.,静负载,;,固定负载,relay switch,继电器开关,lead-acid

3、 battery,铅酸蓄电池,知 识,准 备,5,Starting-motor system,任务,实施,The starting system,turns the crankshaft of the internal combustion engine at first.After that,the engine can use the power of the burning air fuel mixture to run by itself.It mainly consists of a starter motor and the control circuit(shown in figure 5.1.1).A starter motor converts electrical energy stored in the battery into a mechanical force(torque)to start the internal combustion engine.The system must be capable of supplying sufficient po

4、wer to rotate the engine at the minimum speed required to successfully initiate the combustion process in the engine cylinders.In modern vehicles this is approximately 100 rpm.,The internal combustion engine,is not self-starting and this minimum speed is required to allow the engine to form a reasonably well-atomized fuel mixture in the cylinder and compress it sufficiently for combustion to take place.In addition the starting motor must be able to operate with the very high cyclic torque demand

5、 required when rotating an internal combustion engine at cranking speed.The speed must be adequate to allow the momentum of the moving parts to carry the engine over from one firing stroke to another.,6,The starting-motor system,任务,实施,7,Starting-motor system,任务,实施,A starter-motor pinion driving an engine flywheel must exert sufficient torque to provide breakaway from the static condition,i.e.it must rotate the engine from standstill and accelerate up to cranking speed.Interestingly the main cons

6、ideration that affects the torque required to start the engine(apart from its type-spark or compression ignition)is not the total displacement of the engine but the displacement of the individual cylinders.This dictates the peak torque which must be overcome to generate the compression pressures in the cylinders,i.e.larger cylinders require larger starter motors,not necessarily larger engines.,The starting process,All vehicle electric starter motors operate in a similar sequence as follows(see t

7、he figure 5.1.2):,1.Drive engagement:when the driver requests an engine start,the starting motor has to first establish a mechanical link between itself and the engine.The starter motor is mounted somewhere on the engine block,normally via a flange-type mounting,and drives a gear wheel mounted on the engine flywheel at the back of the engine.,8,Starting-motor system,任务,实施,On requesting,a start,the starter motor drive pinion must move into position and engage with the flywheel teeth.If tooth-to-t

8、ooth blocking occurs,then the engagement system must compensate for this and turn the pinion so that the teeth misalign and then engage correctly,thus being positioned properly for torque transmission.This status is a prerequisite before the motor can be supplied with full battery current to start the engine.,2.Torque transmission,:once the drive pinion is fully engaged into the flywheel ring gear teeth,transmission of torque to rotate the engine can begin.At this point,the motor can be switched

9、 on with full power.This is normally effected via a solenoid switch which is appropriately rated to handle the large current with minimal electrical resistance.The motor begins to rotate and,due to the transmission ratio between the starter and engine,a large amount of torque is applied to the crankshaft to overcome the static friction and rotate the engine.The compression and expansion in the engine cylinders means that the torque required varies considerably during the process.,9,Starting-moto

10、r system,任务,实施,3.Engine start-up:a warm,modern,fuel-injected engine will normally start within two revolutions.When cold,the engine needs longer.As soon as fuel is injected/ignited the engine will generate its own torque and therefore increase the rotation speed of the engine.After a short time the engine accelerates the starter and at this point,even if the motor is still powered,the torque must not be transmitted back from the engine as this will over-speed the starter motor and cause permanen

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