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无锡职业技术学院毕业设计说明书 1 原 文: Guards against holds dead braking system (ABS) ABS development histories and introduces ABS is an item only then starts the application in the end of the 80s the new technology, now already became the common passenger vehicle to have the support. Statistics have indicated, the automobile meets suddenly when the situation sends the braking, 90% above drivers often meet a foot the brake pedal to step on come slam on the brakes, this time vehicle to be extremely easy to produce slip and have the side-slipping, namely the people are named “fling the tail”, this will be one kind extremely easy to create the traffic accident the phenomenon. Creates the automobile side-slipping the reason to be very many, for example the moving velocity, the state of ground, the tire structure and so on can create the side-slipping, but the most basic reason is the automobile when the emergency brake the wheel tire and the ground rolling friction can become the sliding friction suddenly, the tire stresses the soil fertility to lose nearly, although this very moment driver sways from side to side the steering wheel also to be able not to help matters. Has the side-slipping phenomenon basic reason in view of this kind, the automobile expert dispatches a vehicle on the development with the ABS this kind of set of skid prevention arresting gear. The automobile guards against holds the dead braking system to have many types, now common is four channel ABS system and three channel ABS type. These types guard against hold the dead braking system the sensor through to examine the wheel the rotational speed to adjust the hydraulic pressure to prevent the wheel hugs dies. Some people thought the automobile assembles ABS to think drives may the capriciousness, the blind drive fast did not fear, this is the extremely wrong understanding. The automobile installed ABS not to install ABS in the brake effect aspect to be more ideal than, this was affirmative, but ABS also only could under certain condition, be able to play its role fully. For example gets on the brakes suddenly on the wet slippery path, the ABS system may enable the pilot to maintain the vehicles 无锡职业技术学院毕业设计说明书 2 travel to be steady, stops in the short distance the automobile. But in not the wet slippery road surface, cannot reduce the stopping distance generally, but may reduce and avoid “flinging the tail” the phenomenon. The road surface test research indicated that, in the sand rock road or other soft road surfaces, the ABS system even can increase the vehicles the stopping distance, because the stopping distance length and the road surface friction coefficient concerns with the tire. Therefore, in order to reduce the stopping distance effectively, on many automobiles all installs has EBD (Electric Brake force Distribution), Chinese translates “the electronic braking force assignment”. EBD in front of ABS movement the sixth branch after balanced the wheel ground according to the vehicles load to stress the soil fertility, carried on the rational distribution to the trailing wheel braking force, might reduce the automobile stopping distance effectively, in fact got up the ABS enlarged function. Therefore many automobiles all have “ABS+EBD ” the installment, improves and enhances ABS the effect. Now the automobile assembles ABS is one kind of electrically controlled installment, it only can mechanically after the procedure which establishes carry out the movement according to the sixth branch. If the driver did not understand ABS the function, is very possibly contrary to what expects. The automobile applies the brake when ABS checks the way with the spot to be possible to prevent vehicles when brake loses changes ability, plays time the control vehicles stopping role. But plays the operation role is radically the driver, when the driver steps on the brake pedal while the emergency case the also jerk steering wheel (many to be insufficiently experienced or being panic-stricken instinct movement often is fiercely jerk steering wheel).If the vehicles have not installed ABS to cause the braking system to hug die, cannot have an effect to the steering wheel extreme response, this time the driver cannot control the direction through the steering wheel which the vehicles move; But if installed the ABS system to let the driver be able to control the steering wheel, then could cause the situation in the flurried situation to the steering wheel extreme response to become worse. Because the sudden jerk steering wheel, often can produce the automobile the side-slipping 无锡职业技术学院毕业设计说明书 3 to occur suddenly the accident. American Highway Safety control Association (NHTSA) believed through the test that, the installment has ESP to control the vehicles to the driver to be possible to have the very big help. ESP (electrically controlled travel steady system, English full title Electronic Stab lit Program) contains ABS and ASR, is in these two kind of system function extending, it can prevent wheel when brake hugs dies with in the start time slips. The unceasing surveying examines the vehicles the travel condition ,when has the emergency case it can rapidly respond, adjusts each wheel through the hydraulic pressure regulator the brake pressure and intervenes the engine the force of traction, reduces the vehicles to ides slip the danger. Some research indicated that, ESP can cause the traffic accident to reduce 50%. 10 year before last, if the passenger vehicle installment has ABS (to guard against hugs dies braking system), not only explain ad this vehicle the security performance stands out, moreover the scale quite is also high-level. Today, installed ABS the passenger vehicle already quite to be common, the economy vehicle also installed has ABS. Along with is more and more high to the auto safety performance quest, some center, the high link passenger vehicle already did not satisfy ABS, but also installed ASR (actuation skid prevention system, also called force of traction control system) or ESP (electrically controlled travel steady system),makes the automobile the security performance further to enhance. The ASR function is when pick-up skidding rate control in curtains cope, thus prevented the driving gear fast skids. Its function one enhances the force of traction; Two, maintains the automobile the travel to be stable. The travel when the easy slippery road surface ,does not have ASR the pick-up the driving gear to be easy to slip; If after is the vehicles which actuates is easy to fling the tail, like is the vehicles easy direction which front actuates to lose control When has ASR, auto mobile when acceleration cannot have or can reduce this kind of phenomenon. When curve, if has the driving gear to slip can cause the entire vehicles to a side displacement, when has ASR can cause the vehicles to change along the correct route. 5th, 2 ABS structure and the principle 1,the ABS system 无锡职业技术学院毕业设计说明书 4 can prevent the wheel hugs dies, has applies the brake when the yawing stab ility is good, applies the brake when still to have changes the ability ,reduces merit and so on stopping distance. The rich advantage card ABS system, is three channels ABS adjustment return routes, the front wheel alone adjusts, trailing wheel take a two turns of center grounds coefficients of adhesion low side as basis unification adjustment. The ABS system mainly by the ABS controller (including electronic control unit, hydraulic pressure unit, hydraulic pump and so on), four wheels tachometer generator, the ABS breakdown tell-tale light, applies the brake the tell-tale light and so on to be composed. The ABS system basic principle of work is: The automobile in applies the brake in the process, the wheel tachometer generator unceasingly each wheel rotational speed signal prompt transportation for the ABS electronic control unit (ECU), the control logic which ABS the ECU basis establishes the signal which inputs to 4 tachometer generators carries on processing, calculates the automobile the reference vehicle speed, various wheels speed and reduces the speed, determines various wheels the slipping rate. If some wheel slipping rate surpasses supposes the definite value, ABS ECU sends out the command control hydraulic control unit, causes in this wheel brake wheel cylinder the brake pressure to reduce; If some wheel slipping rate had not achieved supposes the definite value, ABS ECU on the control hydraulic pressure unit, causes this wheel the brake pressure to increase; When some wheel slipping rate approaches to supposes the definite value, ABS ECU on the control hydraulic control unit, causes this wheel brake pressure maintenance to be certain. Thus causes each wheel the slipping rate maintenance in the ideal scope, prevented 4 wheels completely hug die. In applies the brake in the process, if the wheel has not held the dead tendency, the ABS system will not participate in the brake pressure control, this time will apply the brake the process and the convention braking system is same. If ABS will appear the break down, the electronic control unit no longer will carry on the control to the hydraulic pressure unit, and will lighten the display board on ABS breakdown tell-tale light, will send out the warning signal to the pilot, this time ABS will not play 无锡职业技术学院毕业设计说明书 5 the role, will apply the brake the process and does not have ABS the convention braking system work to be same. 5th, the ABS system major component structure and the principle of work (1) wheel tachometer generator wheel tachometer generator function is bequeaths the wheel rotational speed signal the ABS electronic control unit. MK20- I ABS system altogether has 4 wheels tachometer generator, the front wheel tooth ring (43 teeth) installs on the drive shaft, the tachometer generator installs in knuckle on, like the chart 8-2 shows. The trailing wheel tooth ring (43 teeth) install on the after wheel hub, the tachometer generator installs on the fixed support. The sensor and the magnetic tooth ring is composed by electromagnetism induction type transmit. transmit the reason permanent magnetic core and the induction coil composition, the tooth ring is made by the ferromagnetic material. When the tooth ring revolves ,addendum and space between teeth in turn in turn to magnetic core, when the tooth ring changes to the addendum and transmit a magnetic core relative, between transmit magnetic core and tooth ring gap smallest, has the magnetic line of force by the permanent magnetic core on through the tooth ring, around the induction coil magnetic field is easily strong, like the chart 8-4 (a) shows; But when the tooth ring rotates to the space between teeth and transmit the magnetic core relative, between transmit magnetic core and tooth ring gap biggest, has the magnetic line of force by the permanent magnetic core not easily through the tooth ring, around the induction coil magnetic field is weak, like the chart 8-4 (b) shows. This time, the magnetic flux rapid in turn changes, will be able to produce the alternating voltage in the induction coil, the alternating voltage frequency with the vehicle rotates the intensive proportion change. The electronic control unit may the voltage pulse frequency which inputs through the tachometer generator carry on processes determines the wheel the rotational speed, the automobile reference velocity and so on. (2) ABS the controller ABS controller by the ABS electronic control unit (J104), the hydraulic control unit (N55), the hydraulic pump (V64) and so on is composed. 1st, the electronic control unit electronic control 无锡职业技术学院毕业设计说明书 6 unit is the ABS system control center, it is a microcomputer in fact, therefore often is called ABS (ECU) the computer. ABS ECU by the input circuit, the digital controller, the output circuit and the warning electric circuit is composed. The primary mission is the continuous monitoring accepts the pulse signal which 4 wheels tachometer generator sends, and carries on the Urey comparison, the analysis enlarges and distinguishes processing, the idea figures out the wheel rotational speed, the wheel reduces the speed as well as applies the brake the slipping rate, again carries on the logical comparison to analyze 4 wheels to apply the brake the situation, once judges the wheel to be going to hug dies, it enters immediately guards against holds the dead control condition, sends out the instruction through the electronic control unit to the hydraulic pressure unit, controls on the brake wheel cylinder oil duct the solenoid valve to pass breaks adjusts the brake pressure with the hydraulic pump work, prevented the wheel hugs dies. ABS ECU also unceasingly carries on the monitoring to own work. Because in ABS ECU has two quite same not less than microprocessors, they carry on processing according to the similar procedure to the input signal, and the intermediate result and the final outcome which produces it carry on the comparison, one also the discovery result is in consistent namely determines own existence breakdown, it can the automatic shut-off ABS system. In addition ABS ECU also unceasingly monitors in the ABS system other parts working conditions, once the ABS system appears the breakdown, like the wheel rate signal vanishes, hydraulic pressure pre sure drop and so on, ABS ECU can send out the instruction to close the ABS system, and causes the convention braking system work, simultaneously remembered the breakdown information storage, and lightens the display board on ABS breakdown lights, sends out the police to the pilot to show the signal, this time should promptly inspect the repair. When the ignition lock puts through, ABS ECU starts to carry on the self-checking procedure, carries on self-checking to the system, this time the ABS breakdown lights lighten. If self-checking later discovered the ABS system existence interferes with its normal work the breakdown, it will close the ABS system, will restore the convention braking system, on the display board the ABS 无锡职业技术学院毕业设计说明书 7 breakdown lights continuously lightens, warns the pilot ABS system existence breakdown. After self-checking had ended, the ABS breakdown lights extinguish, indicated the system work is normal Because the self-checking process probably needs 2s, therefore in normal condition, when the ignition lock puts through, the ABS breakdown lights lighten 2s, then automatically extinguishes again, is normal. Otherwise if the ignition lock puts through time, the ABS breakdown lights are not bright, explained the ABS breakdown lights or its line existence breakdown, should carry on the overhaul to it. 2nd,hydraulic control unit and the hydraulic pump hydraulic control unit installs in the brake master cylinder with the brake wheel cylinder between, uses the integral-type structure (like chart 8-5 to show).The primary mission is the transformation carries out the ABS ECU instruction, in automatic control brake low pressure. The low pressure pot and the electrically operated hydraulic pump gather is a body installs on the hydraulic control unit. The low pressure oil tank function is uses in the temporary storage the brake fluid which flows out from the wheel cylinder, the pulsation which relaxes the brake fluid flows out from the brake wheel cylinder when produces. Electrically operated hydraulic pressure .The electrically operated hydraulic pump function is promptly delivers in the brake pressure stage inflow low pressure pot brake fluid to the brake master cylinder, simultaneously in exerts the pressure stage, absorbs surplus from the low pressure pot brake, pumps into applies the brake the circulatory system, for the hydraulic system by the pressure support, the increase applies the brake the potency. The electrically operated hydraulic pump revolution is by the electronic control unit control. The hydraulic control unit (N55) valve in vivo including 8 solenoid valves, each return route each pair, often advances the oil valve, often shuts the delivery valve. It in the brake master cylinder, the brake wheel cylinder and returns to between the oil duct to establish the relation, realization pressure lifting, the pressure maintenance and the pressure drop function, prevented the wheel hugs dies, its principle of work as follows: (1)starts when the de boost phase (system flowing tubing head pressures abolishment) starts to apply 无锡职业技术学院毕业设计说明书 8 the brake, the pilot steps on the brake pedal, the brake pressure by the brake master cylinder production, frequently opens does not bring the voltage the charging valve to affect to the wheel brake wheel cylinder on, this time, does not bring the voltage the delivery valve still to close, the ABS system has not participated in the control, the entire process and the convention hydraulic brake system is same, the brake pressure unceasingly rises. 翻 译: 防抱死制动系统( ABS) ABS 的发展历史及简介 ABS 是一项在 80 年代末才兴起应用的新技术,现在已经成为一般轿车的必装件了。 据统计,汽车突然遇到情况发刹车时,百分之 九十以上的驾驶者往往会一脚将刹车踏板踩到底来个急刹车,这时候的车子十分容易产生滑移并发生侧滑,即人们俗称的“甩尾”,这是一种非常容易造成车祸的现象。造成汽车侧滑的原因很多,例如行驶速度,地面状况,轮胎结构等都会造成侧滑,但最根本的原因是汽车在紧急制动时车轮轮胎与地面的滚动摩擦会突然变为滑动摩擦,轮胎的抓地力几乎丧失,此时此刻驾驶者尽管扭动方向盘也会无济于事。针对这种产生侧滑现象的根本原因,汽车专家就研制出车用 ABS 这样一套防滑制动装置。 汽车防抱死制动系统有许多类型,现在常见是四通道 ABS 系统和三通道 ABS类型。这些类型的防抱死制动系统的 transmit 器通过检测车轮的转速以调整液压来防止车轮抱死。 有人以为汽车装配 ABS 就以为开车可以随意性,盲目开快车也不怕,这是非常错误的认识。汽车安装了 ABS 在制动的效果方面比没有安装 ABS 理想,这是肯定的,但 ABS 也只能在一定的条件下,才能充分发挥它的作用。例如在湿滑的道路上突然刹车, ABS 系统可以使驾驶员能够保持车辆行驶平稳,在较短的距离内将汽车刹住。但在不湿滑的路面上,一般不能缩短刹车距离,但可以减少和避免“甩尾”现象。路面的测试研究表明,在沙石路或其他松软 的路面上, ABS系统甚至会增大车辆的刹车距离,因为刹车距离的长短与路面的摩擦系数和轮胎有关。因此,为了有效减小刹车距离,许多汽车上都安装有 EBD( Electric Brakeforce Distribution),中文译“电子制动力分配”。 EBD 在 ABS 动作之前巳经根据车辆载荷平衡了车轮的地面抓地力,对后轮的制动力进行合理分配,可以有效地缩短汽车制动距离,实际上起到 ABS 的增补功能。因此许多汽车都有“ ABS EBD”的装置,改善和提高 ABS 的功效。 无锡职业技术学院毕业设计说明书 9 现在汽车装配的 ABS 是一种电控装置,它只能机械地按照巳经 编制好的程序来执行动作。如果驾驶者不了解 ABS 的功能,很可能事与愿违。汽车制动时 ABS用点刹方式可以防止车辆在制动时丧失转向能力,起
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