桑塔納LX型轎車-汽車差速器的設(shè)計(jì)說明書

桑塔納LX型轎車-汽車差速器的設(shè)計(jì)說明書,桑塔納,LX,轎車,汽車,差速器,設(shè)計(jì),說明書 附錄一 在汽車工程中的研究進(jìn)展：制動(dòng)輔助差速器鎖止系統(tǒng) 摘要：“它需要一個(gè)汽車組裝螺栓至 8460、一個(gè)螺母到散布在它所有的路?！?在過去的 10 年中，一些最大的汽車技術(shù)領(lǐng)域的研究進(jìn)展已經(jīng)出現(xiàn)在汽車安全領(lǐng)域。由于微處理器的速度，縮形技術(shù)（miniaturization)、軟件開發(fā)等技術(shù)的 發(fā)展的促進(jìn)，汽車也繼續(xù)發(fā)展。提出了一種新的方法，在這，我計(jì)劃用一個(gè)電 子氣動(dòng)電路自動(dòng)控制牽引車輛。在普通情況下，當(dāng)車輛是驅(qū)動(dòng)上下直道，或如 果兩個(gè)速度之間的差異的（后）輪是在指定的限制之內(nèi)，信號(hào)將不會(huì)生成的電 子電路。這將幫助汽車更好的控制差異。但是，如果速度之間的差異是定的超 越極限的信號(hào)，將生成的這將啟動(dòng)電路的電子氣動(dòng)電路。這將會(huì)逐漸的制動(dòng)那 個(gè)最快的車輪，直到它受到牽引。因此，該輪將不會(huì)失去牽引力。對(duì)于現(xiàn)在存 在的并已經(jīng)得到制造公司和最終的消費(fèi)者成本意識(shí)的支持的系統(tǒng)，該系統(tǒng)能確 保減少超過 50%的資本投資。 關(guān)鍵詞：差速鎖，牽引防滑控制差分，氣動(dòng)剎車 1. 簡(jiǎn)介 你真的是舒適的操縱你的車走過泥濘的小路嗎？在干燥的條件下，當(dāng)有足夠的牽引力，到車輪的扭矩的量是被發(fā)動(dòng)機(jī)和傳動(dòng)裝置限制；在牽引力較小的情況， 例如當(dāng)在冰上開車，扭矩的量是有限的最大量，不會(huì)造成車輪滑下條件。所以， 即使一輛車可以產(chǎn)生更大的扭矩，需要有足夠的牽引力來傳遞扭矩到地面。只要輪胎抓住路面，提供一種抗旋轉(zhuǎn)力驅(qū)動(dòng)車輛前進(jìn)即可。 傳動(dòng)系統(tǒng)扭矩是均勻分布的兩個(gè)后輪的驅(qū)動(dòng)橋軸。當(dāng)一個(gè)輪胎的遭遇道路上的滑點(diǎn)，失去牽引力，旋轉(zhuǎn)阻力降低，車輪開始旋轉(zhuǎn)，因?yàn)榇藭r(shí)抵抗力有所下降，傳遞到車輪的扭矩變化，并且此時(shí)車輪不能被驅(qū)動(dòng)行駛。車輛在這種情況下是靜止，只有車輪在滑點(diǎn)旋轉(zhuǎn)，因此，車輛不動(dòng)。這種情況就是差動(dòng)齒輪要解決的地方。隨著牽引力減少，輪子以非常高的速度轉(zhuǎn)動(dòng)，產(chǎn)生的熱量迅速增加， 潤(rùn)滑油膜破裂，金屬金屬發(fā)生接觸，零部件損壞。如果現(xiàn)在輪突然有牽引，突然的沖擊能使傳動(dòng)軸損壞嚴(yán)重。 所以目前我們?nèi)绾慰朔@些困難? 為了克服這些問題，不同廠家開發(fā)了限滑差速器。在汽車應(yīng)用，限滑差速器 （LSD）是一個(gè)修改或衍生式差動(dòng)齒輪裝置，其允許在輸出軸的旋轉(zhuǎn)速度差一些， 但是不允許速度的差異增加超出了預(yù)置數(shù)值。在一輛汽車,這樣的限滑差有時(shí)被用來代替標(biāo)準(zhǔn)的差異,在這里以更大的復(fù)雜性為代價(jià)，傳達(dá)一定的動(dòng)態(tài)優(yōu)勢(shì)。一種防滑的主要優(yōu)勢(shì)微分是考慮一個(gè)標(biāo)準(zhǔn)的情況下（或“打開”）在一輪差有沒有聯(lián)系所有地面。在這種情況下，接觸輪將保持固定的，而非接觸輪旋轉(zhuǎn)的兩倍預(yù)期速度–傳遞的扭矩是相等的兩車輪，但不會(huì)超過扭矩閾值移動(dòng)車輛，使車輛保持靜止。在日常使用的一般類型的道路，這樣的情況幾乎不可能的，所以正常的差就夠了。對(duì)于更多使用要求，如駕駛越野車，或高車輛性能，這種狀態(tài)是不可取的，但 LSD 可以用來處理這種情況。通過限制一對(duì)驅(qū)動(dòng)輪之間的速度差，有用扭矩可被傳遞，只要有一些摩擦提供在至少一個(gè)輪子。離合器式 LSD 響應(yīng)于驅(qū)動(dòng)軸的扭矩。越多的驅(qū)動(dòng)軸輸入扭矩，離合器被擠壓在一起越困難，因此更密切的驅(qū)動(dòng)輪連接更好。 限滑差速器的限制 a）熱耗散導(dǎo)致潤(rùn)滑油膜破裂，金屬金屬接觸的情況。b）如果通電離合器摩擦是整個(gè)組件損壞，必須拆卸。c）高質(zhì)量的潤(rùn)滑要求。 D）由于機(jī)械大量存在部件，可靠性低。 E）隨著車速的增加，車輛的噪聲也增加。 f）復(fù)雜昂貴。 二．提出輔助鎖止差速器系統(tǒng) 在這種新的方法，有一個(gè)電子和一個(gè)氣動(dòng)回路自動(dòng)控制車輛的牽引力。在正常情況下,當(dāng)車輛行駛在直路,或者兩個(gè)(后)輪子的轉(zhuǎn)動(dòng)速度之間的差異低于指定的限制,將沒有將電子電路產(chǎn)生的信號(hào)。這有助于車輛協(xié)商更好的牽引力控制系統(tǒng),微分動(dòng)作是不變的。但如果速度差超過某一限度，信號(hào)由電子電路產(chǎn)生的， 它會(huì)啟動(dòng)氣動(dòng)回路。這導(dǎo)致漸進(jìn)制動(dòng)的速度直到它獲得牽引輪。因此，車輪將永遠(yuǎn)不會(huì)失去牽引。根據(jù)輸入的傳感器數(shù)據(jù)，在 b ADL s 控制模塊檢測(cè)到車輪對(duì)滑， 將脈沖常開電磁閥閉合，電路進(jìn)。同時(shí)，該控制模塊打開常閉電磁閥這個(gè)電路。這導(dǎo)致了氣壓作用在制動(dòng)片上，形成人工制動(dòng)。一旦影響其他輪回到相同的速度， 控制模塊返回各自的閥門正常位置釋放任何殘余壓力，消除氣動(dòng)剎車電路的影 響。 圖 1 示意電路 b ADL s 圖 2 在 b ADL s 電路工作 圖 2 BADLS 電路的工作流程圖解釋圖 1 所示電路的工作首先在圖 2 上面給出流程圖顯示了正常的工作打破電路,后者顯示了工作時(shí)電路工作。在正常的突發(fā)狀況電磁閥 1 是在封閉條件下,空氣從主人繞過輔助缸流在主制動(dòng)電路電路通過電磁閥 1,因此正常的打破行動(dòng)是實(shí)現(xiàn)。狀況下滑單片機(jī)常閉電磁閥的啟動(dòng)和常開電磁閥 2,因此人工制動(dòng)應(yīng)用于需要的輪子。 A. BADLS 控制模塊 該系統(tǒng)提供了一種控制系統(tǒng)，至少兩驅(qū)動(dòng)輪，一個(gè)微分傳輸動(dòng)力從發(fā)動(dòng)機(jī)到驅(qū)動(dòng)車輪，且在驅(qū)動(dòng)輪之間允許相對(duì)速度?？刂葡到y(tǒng)包括兩個(gè)輪速傳感器，比較器電路和控制電路。車輪速度傳感器被配置為檢測(cè)兩驅(qū)動(dòng)輪角速度和產(chǎn)生的信號(hào)。比較器電路耦合到車輪速度傳感器并且傳感器的配置為比較信號(hào)并生成一個(gè)代表的驅(qū)動(dòng)車輪的滑移程度的信號(hào)?？刂齐娐肥邱詈捅容^器電路和制動(dòng)輔助微分鎖定機(jī)構(gòu)，并且被配置為在發(fā)生滑動(dòng)時(shí)產(chǎn)生控制信號(hào)。 三.架構(gòu)FORBRAKE 輔助微分鎖定系統(tǒng) 控制電路所示圖 3 配置接收代表車輛操作參數(shù)的信號(hào)(輪子滑動(dòng)的條件)和生成對(duì)應(yīng)于為了限制兩個(gè)驅(qū)動(dòng)輪相對(duì)速度的制動(dòng)輔助微分鎖機(jī)制狀態(tài)的控制信號(hào)。傳感器是與后輪相關(guān)聯(lián)的控制邏輯通過不斷循環(huán)的控制電路的執(zhí)行確定微分鎖定機(jī)制基于操作參數(shù)的期望狀態(tài)?？刂齐娐愤m用于一個(gè)適當(dāng)由微分鎖定機(jī)制引起的根據(jù)理想狀態(tài)的結(jié)合或分離的控制信號(hào)。車輪速度傳感器配置為檢測(cè)兩個(gè)后輪的速度和生成一個(gè)輪子速度給定信號(hào)作為輸入到微控制器。一個(gè)比較器的電路耦合到微控制器車輪速度傳感器產(chǎn)生代表驅(qū)動(dòng)輪的滑度的信號(hào)。一個(gè)控制電路耦合比較器電路和微分鎖定機(jī)制并且配置為當(dāng)一個(gè)預(yù)先確定的滑動(dòng)發(fā)生，生成控制信號(hào)同時(shí)應(yīng)用 微分鎖定機(jī)制的控制信號(hào)來限制應(yīng)用人工制動(dòng)驅(qū)動(dòng)電磁閥的驅(qū)動(dòng)輪之間的相對(duì)速度控制微分電路進(jìn)一步配置為當(dāng)滑動(dòng)的程度降低且低于預(yù)定閾值時(shí)脫離鎖定機(jī)制車輪速度傳感器提供為每個(gè)驅(qū)動(dòng)輪,每個(gè)輪速度傳感器被配置為生成輪速度信號(hào)和應(yīng)用車輪速度信號(hào)比較器電路,其中控制電路配置為生成控制信號(hào)限制驅(qū)動(dòng)車輪滑動(dòng)時(shí)之間的相對(duì)速度。 四.規(guī)范的電子組件 ? 微控制器 ? 模擬到數(shù)字轉(zhuǎn)換器 ? 信號(hào)調(diào)節(jié)器 1。晶體管 2。二極管 a. 微控制器 使用 BADLS：?jiǎn)纹瑱C(jī)的輸入是兩個(gè)車輪速度傳感器所傳輸?shù)乃俣?。微控制器獲得不同的速度傳感器的輸出之間的它的最大允許變化的比較。如果變化超出規(guī)定值，它可以激活電磁閥，從而使輔助電路，避免任何打滑的車輪 b. 電磁閥 使用 BADLS：他們作為 ON/OFF 開關(guān)和控制加壓空氣進(jìn)入副回路流量。型： 滑閥式 c. 模擬數(shù)字轉(zhuǎn)換器 使用 BADLS：從車輪速度的模擬速度信號(hào)傳感器是由 ADC 轉(zhuǎn)換成數(shù)字格式是提供給單片機(jī)輸入 d. 空氣制動(dòng)系統(tǒng) 在空氣制動(dòng)的最簡(jiǎn)單的形式，稱為直的空氣系統(tǒng)，在氣缸內(nèi)壓縮空氣推動(dòng)活塞?；钊B接到制動(dòng)蹄，可與輪摩擦，使用所產(chǎn)生的摩擦，降低牽引。壓縮空氣來自一個(gè)空氣壓縮機(jī)和被流通的由管道和軟管組成的氣動(dòng)線。為了應(yīng)用制動(dòng)力， 制動(dòng)蹄和壓縮空氣被使用。在一般的空氣制動(dòng)系統(tǒng)包括一個(gè)壓縮機(jī)單元，空氣儲(chǔ)液罐，制動(dòng)氣室和輪機(jī)構(gòu)。隨時(shí)保持足夠的制動(dòng)力，即使發(fā)動(dòng)機(jī)不運(yùn)轉(zhuǎn)和空氣儲(chǔ)罐還是有必要具備的。保持空氣壓力，這是小的空氣泵，使用。壓縮機(jī)把空氣從大氣通過濾波和壓縮空氣送入通過卸荷閥的水庫(kù)，被解除在一預(yù)定的儲(chǔ)層壓力和減輕壓縮機(jī)負(fù)荷。儲(chǔ)層中的空氣到各種配件同時(shí)也對(duì)制動(dòng)氣室也稱為膜單元在每一輪，通過制動(dòng)閥。制動(dòng)控制閥與司機(jī)可以控制強(qiáng)度打破按要求。卸荷閥空氣制動(dòng)系統(tǒng)用于調(diào)節(jié)管路壓力 五.測(cè)試和評(píng)價(jià)參數(shù) 該系統(tǒng)已在巴哈的印度汽車研究協(xié)會(huì)（協(xié)會(huì)）測(cè)試車測(cè)試。這確實(shí)幫助巴哈隊(duì)經(jīng)常遭遇的類似 SAE 情況打滑的車輪。由于車輛滑移通常是大約 12-15%而轉(zhuǎn)動(dòng)，單片機(jī)的系統(tǒng)的設(shè)計(jì)是為了活躍在約 20%轉(zhuǎn)動(dòng)的條件和停用約 5%的滑動(dòng)。該系統(tǒng)測(cè)試成功，下一步將是可行的一些小的修改后的汽車中的實(shí)現(xiàn)。車輛被頂起一輪與其他輪落在地面。這樣做是為了模擬最大滑移條件。這種情況會(huì)出現(xiàn)在實(shí)際條件下，如當(dāng)車輛正在巖石地形時(shí)，發(fā)動(dòng)機(jī)啟動(dòng)和加速。由于一輪空氣中， 車輛沒有向前移動(dòng)，頂車輪旋轉(zhuǎn)過?，F(xiàn)在，電磁閥被激活了提供了滑輪和人工制動(dòng)。 六.成本比較表 從以上可以看出，此系統(tǒng)確保超過 50%的資本投資減少相較于現(xiàn)有的系統(tǒng)。 七.優(yōu)勢(shì) A） 可以在車輛氣動(dòng)容易實(shí)現(xiàn)制動(dòng)系統(tǒng)稍作修改。 B） 電子電路使用，響應(yīng)時(shí)間，控制和可靠性均優(yōu)于現(xiàn)有的系統(tǒng)。 C） 低級(jí)別潤(rùn)滑油可作為熱損失減少。 D）最后但并非最不重要的，系統(tǒng)是經(jīng)濟(jì)的和簡(jiǎn)單的。 八.局限性 整體效率取決于組合效率無論是電子以及氣動(dòng)系統(tǒng)。 九.應(yīng)用 該系統(tǒng)可以成功地將車輛氣動(dòng)/液壓制動(dòng)系統(tǒng)，提高牽引。它可以用在特別全地形車（ATV）和車輛的運(yùn)行在高海拔地區(qū)（軍用車輛），雪牽引過度流失的原因。該系統(tǒng)確保了超過 50%的資本投資減少相比于現(xiàn)有的系統(tǒng)，保證了“奮進(jìn)號(hào)”的成本效益。 致 謝 作者感謝 r.b.patil 教授，系主任，陸軍技術(shù)研究所，印度博士和 KC 埃武拉在印度汽車研究協(xié)會(huì)（協(xié)會(huì)），他們的指導(dǎo)和支持。 參考文獻(xiàn) 【1】杰克厄爾賈維克，汽車技術(shù)-系統(tǒng)方法（德爾瑪湯姆森學(xué)習(xí)，2000） 【2】T.K.加勒特，K. W.牛頓，戰(zhàn)馬，機(jī)動(dòng)車輛（巴特沃斯 heinmann，2001） 附錄二 Advances in Automobile Engineering: Brake Assisted Differential Locking System Kanwar Bharat Singh Abstract -“It takes 8,460 bolts to assemble an automobile, and one nut to scatter it all over the road.” Some of the biggest advances in the field of automotive technology in the past 10 years have come in the area of safety.Spurred by the improvements in the microprocessor speed,miniaturization, and software development, the automobile continues to evolve. In this new approach proposed, I am going to have an electronic and a pneumatic circuit to automatically control the traction of the vehicle. During ordinary conditions, when the vehicle is driven down a straight road, or if the difference between speeds of the two (rear) wheels is below a specified limit, no signal will be generated by the electronic circuit. This helps the vehicle negotiate the turns with better traction control as differential action is unaltered. But if the difference between speeds is beyond a specified limit, the signal will be generated by the electronic circuit which will actuate the pneumatic circuit. This causes gradual braking on the faster wheel until it gains traction. Hence, the wheels will never lose traction. This system ensures a reduction of more than 50% in the capital investment as compared to the already existing systems can tilt the scales in the favour of the manufacturing company and eventually the cost conscious consumer. . Keywords – Differential locking, traction control, Limited slip differential, pneumatic braking. I. I NTRODUCTION Are you REALLY comfortable manoeuvring your vehicle through a muddy patch? In dry conditions, when there is plenty of traction, the amount of torque applied to the wheels is limited by the engine and gearing; in a low traction situation, such as when driving on ice, the amount of torque is limited to the greatest amount that will not cause a wheel to slip under those conditions. So, even though a car may be able to produce more torque, there needs to be enough traction to transmit that torque to the ground .As long as the tyre grips the road, providing a resistance to turning, the drive train forces the vehicle forward. Manuscript received March 22, 2008. This work was supported in part by the Automotive Research Association of India (ARAI), pune, India. The Author is with Tata Motors Ltd, pune, India, phone: +919250006237 fax: 91 124 2805140 e-mail: Kanwar.singh@tatamotors.com Driveline torque is evenly distributed between the two rear drive axle shafts by the differential. When one tyre encounters a slippery spot on the road, it looses traction, resistance to rotation drops, and the wheel begins to spin. Because the resistance has dropped, the torque delivered to both the wheels changes. The wheel with good traction is no longer driven. If the vehicle is stationary in this condition, only the wheel over the slippery spot rotates. Hence the vehicle does not move. This situation places stress on differential gears. As the traction fewer wheels rotates at a very high speed, amount of heat generated increases rapidly, lube film breaks down, metal to metal contact occurs, and the parts are damaged. Now if the spinning wheel suddenly has traction, then the shock of the sudden traction can cause severe damage to the drive axle assembly. So presently how do we overcome these difficulties? To overcome these problems, differential manufacturers have developed the – Limited Slip Differential. In automotive applications, a limited slip differential (LSD) is a modified or derived type of differential gear arrangement that allows for some difference in rotational velocity of the output shafts, but does not allow the difference in speed to increase beyond a preset amount. In an automobile, such limited slip differentials are sometimes used in place of a standard differential, where they convey certain dynamic advantages, at the expense of greater complexity. The main advantage of a limited slip differential is found by considering the case of a standard (or "open") differential where one wheel has no contact with the ground at all. In such a case, the contacting wheel will remain stationary, and the non-contacting wheel will rotate at twice its intended velocity – the torque transmitted will be equal at both wheels, but will not exceed the threshold of torque needed to move the vehicle, thus the vehicle will remain stationary. In everyday use on typical roads, such a situation is very unlikely, and so a normal differential suffices. For more demanding use however, such as driving off-road, or for high performance vehicles, such a state of affairs is undesirable, and the LSD can be employed to deal with it. By limiting the velocity difference between a pair of driven wheels, useful torque can be transmitted as long as there is some friction available on at least one of the wheels. The clutch type LSD responds to drive shaft torque. The more drive shaft input torque present, the harder the clutches are pressed together and thus the more closely the drive wheels are coupled to each other. L imitations of the Limited Slip Differential a) Heat dissipation leads to lube film breakage, metal- to-metal contact occurs. b) If the friction lining of the energized clutch is damaged, the whole assembly has to be dissembled. c) High quality lubrication required. d) Due to presence of large number of mechanical components, reliability is less. e) As the speed increases, noise of vehicle also increases. f) Complicated and costly. II. PROPOSED INNOVATION-BRAKE ASSISTED DIFFERENTIAL LOCKING SYSTEM (BADLS) In this new approach, there is an electronic and a pneumatic circuit to automatically control the traction of the vehicle. During the ordinary conditions, when the vehicle is driven down the straight road, or if the difference between the speeds of the two (rear) wheels is below a specified limit, no signal will be generated by the electronic circuit. This helps the vehicle negotiate the turns with better traction control, as the differential action is unaltered. But if the difference between the speeds is beyond a specified limit, the signal will be generated by the electronic circuit, which will actuate the pneumatic circuit. This causes gradual braking on the faster wheel until it gains traction. Hence, the wheels will never lose traction. The BADLS control module senses that a wheel is about to slip based on the input sensor data and in turn pulses the normally open inlet solenoid valve closed for that circuit. This allows fluid to enter the circuit. At the same time, the control module opens the normally closed solenoid valve for that circuit. This leads to the application of pneumatic pressure on the brake pads, leading to the artificial braking. Once the affected wheel returns to the same speed as the other wheel the control module returns both the valves to their respective normal positions releasing any residual pressure in the pneumatic circuit of the affected brake. Fig. 1 SCHEMATIC CIRCIUT OF BADLS Fig. 2 WORKING OF THE BADLS CIRCUIT Flowchart to explain working of the circuit shown in Fig 1 is given above in Fig 2 First flowchart shows working of normal breaking circuit and the latter shows the working when the badls circuit is working. During normal breaking condition solenoid valve 1 is in closed condition so air from master cylinder flows in main braking circuit bypassing the auxiliary circuit through solenoid valve 1 and thus normal breaking action is achieved. .In slipping condition microcontroller actuates normally closed solenoid valve and normally open solenoid valve 2 and thus artificial braking is applied to the required wheel. A. The BADLS Control module The system is provided a control system, at least two driven wheels, a differential for transmitting power from the engine to the driven wheels and permitting relative velocity between the driven wheels. The control system includes two wheel velocity sensor, a comparator circuit and a control circuit. The wheel velocity sensor is configured to detect the angular velocity of the two driven wheels and to generate a signal. The comparator circuit is coupled to the wheel velocity sensor and is configured to compare the signals of the sensors and to generate a slip signal representative of the degree of slip of the driven wheels. The control circuit is coupled to the comparator circuit and to the brake assisted differential locking mechanism and is configured to generate control signals when a predetermined degree of slip occurs and to apply the control signals to the differential locking mechanism to limit relative velocity between the driven wheels. III. PROPOSED ARCHITECTURE FORBRAKE ASSISTED DIFFERENTIAL LOCKING SYSTEM The control circuit shown below in Fig.3 is configured to receive signals representative of vehicle operating parameters (condition of slipping of wheels) and to generate control signals corresponding to the desired state of the brake assisted differential locking mechanism for limiting relative velocity between two driven wheels. Sensors are associated with the rear wheels. Control logic executed by the control circuit in a continuously cycled routine determines the desired state of the Fig. 3 PROPOSED ARCHITECTURE OF SYSTEM differential locking mechanism based upon the operating parameters. The control circuit applies an appropriate control signal to the differential locking mechanism causing engagement or disengagement in accordance with the desired state. Wheel velocity sensor are configured to detect the velocity of the two rear wheels and to generate a wheel velocity signal given as an input to the micro controller. A comparator circuit of the micro controller is coupled to the wheel velocity sensors generate a slip signal representative of the degree of slip of the driven wheel. A control circuit is coupled to the comparator circuit and to the differential locking mechanism and configured to generate control signals when a predetermined degree of slip occurs and to apply the control signals to the differential locking mechanism to limit relative velocity between the driven wheels by applying artificial braking by actuating the solenoid valves. The control circuit is further configured to disengage the differential locking mechanism when the degree of slip decreases to a level below a predetermined threshold. Wheel velocity sensor is provided for each of the driven wheels, each of the wheel velocity sensors being configured to generate wheel velocity signals and to apply the wheel velocity signals to the comparator circuit, and wherein the control circuit is configured to generate control signals for limiting relative velocity between the driven wheels when slip of any driven wheel exceeds a predetermined threshold value . IV. SPECIFICATIONS FOR ELECTRONIC COMPONENTS ? MICRO CONTROLLER ? ANALOG TO DIGITAL CONVERTER ? SIGNAL CONDITIONER 1. Transistor 2. Diode A.MICROCONTROLLER USE IN BADLS: The microcontroller input is the speed of the two wheel speed sensors. The microcontroller obtains the difference in between the two speed sensor outputs and compares it with the maximum allowable variation. If the variation is beyond the stipulated value, it activates the solenoid valves, thus enabling the auxiliary circuit, avoiding any slipping of the wheels. B.SOLENOID VALVE USE IN BADLS: They act as ON/OFF switches and control flow of pressurized air into the Auxiliary Circuit. TYPE: Spool Type C.ANALOG TO DIGITAL CONVERTER USE IN BADLS: the analog speed signal from the wheel speed sensors is converted into the digital format by the ADC which is supplied as the input to the microcontroller D. AIR BRAKING SYSTEM In the air brake's simplest form, called the straight air system, compressed air pushes on a piston in a cylinder. The piston is connected to a brake shoe, which can rub on the wheel, using the resulting friction to slow the train. The pressurized air comes from an air compressor and is circulated by a pneumatic line made up of pipes and hoses. In order to apply the braking force to the brake shoes, compressed air is used. An air brake system in general includes a compressor unit, air-reservoir tank, brake chamber and wheel mechanism. For maintaining adequate braking force at all times even when the engine is not running and air-reservoir tank is also necessary. To maintain air pressure, which is small air pump, is used. The compressor takes air from the atmosphere through the filter and the compressor air is sent to the reservoir through the unloader valve, which gets lifted at a predetermined reservoir pressure and relieves the compressor load. From the reservoir the air goes to the various accessories and also to the brake chambers also called the diaphragm units at each wheel, through the brake valve. The control of brake valve is with the driver who can control the intensity of breaking according to the requirements. The unloader valve in the air breaking system serves to regulate the line pressure . V. TESTING AND EVALUATION PARAMETERS The system has been tested on a SAE BAJA test vehicle at the Automotive Research Association of India (ARAI), pune. This was done keeping in mind that this application would be really helpful for SAE BAJA teams who encounter conditions like slipping of wheels very often. Since vehicle slip is usually about 12-15% while turning, this microcontroller of the system has been designed to active at about 20% slip conditions and deactivates at about 5% slip. The system was tested successfully and the next step would be practical implementation in automobiles after some minor modification. The vehicle was jacked up on one wheel with the other wheel resting on ground surface .This was done to simulate the condition of maximum slipping. This condition will be present in actual conditions when vehicle is negotiating rocky terrain. The engine was started and accelerated. Due to one wheel being in air, the vehicle did not move forward and the jacked wheel rotated excessively. Now the solenoid was activated for the slipping wheel and artificial braking was provided. As a result the torque transmitting capacity of the wheels increases and consequently, the vehicle pulls over the rocks and gravel on the basis of the torque from the individual wheel. VI. COST COMPARISION TABLE As can be seen from the above table that this system ensures a reduction of more than 50% in the capital investment as compared to the already existing systems. Table I. COMPARISON OF BADLS SYSTEM WITH EXISTING LSD SYSTEM IN THE MARKET VII. ADVANTAGES a) Can be easily implemented in vehicles having pneumatic braking systems with slight modification. b) As electronic circuitry is used, response time, control and reliability are better than the existing systems. c) Low grade lubricants can be used as heat loss is reduced. d) Last but not the least; the system is economical and simple. VIII. LIMITATIONS The overall efficiency depends on the combined efficiency of both the electronic as well as the pneumatic system. IX. APPLICATIONS The system can be successfully incorporated in vehicles having pneumatic/hydraulic braking system, with a view to provide improves traction. It can be put to use in especially All Terrain Vehicles (ATV) and vehicles operating in high altitude areas (vehicles for military application) where snow causes excessive loss of traction. This system ensures a reduction of more than 50% in the capital investment as compared to the already existing systems which ensures the cost effectiveness of the endeavour.