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外文資料譯文
變速器
盡管現(xiàn)代汽車所使用的變速器各式各樣，但它們的工作原理是大致相同的。變速器有液力變速器，也有由制動器和離合器控制的行星齒輪組，行星齒輪組可以提供兩個或三個前進(jìn)擋。
變速器可以提供不同數(shù)值的傳動比，對于發(fā)動機(jī)這很重要。發(fā)動機(jī)低速運(yùn)轉(zhuǎn)時傳遞動力不大。汽車起步時又要求輸出扭矩較大，這使發(fā)動機(jī)就必須高速運(yùn)轉(zhuǎn)。駕駛員掛上第一檔，此時使發(fā)動機(jī)以高速運(yùn)轉(zhuǎn)：其傳動比為發(fā)動機(jī)的曲軸轉(zhuǎn)12圈，后車輪轉(zhuǎn)一圈。這時發(fā)動機(jī)提供的大功率使汽車啟動并快速加速。然后，駕駛員換二檔（分開離合器，使變速器中的齒輪順利換檔），此次后二檔使汽車加速到更高的速度，速比為8：1，最后換到第三檔，在這一檔中，動力通過變速器直接傳遞，傳動軸與發(fā)動機(jī)曲軸轉(zhuǎn)速一致。第三檔的傳動比為1：1。另設(shè)有一倒檔，在這一檔中，傳動軸將朝反方向傳動，從而使汽車實現(xiàn)倒向行駛。
四輪驅(qū)動
在美國，雖然更多的消費(fèi)者不愿再使用運(yùn)動型多功能車(休閑越野車SUV)，而更傾向于選擇轎車和功能交叉型車，但他們依然不愿放棄全輪驅(qū)動（AWD）系統(tǒng)，因為對他們來說，這是一個安全的系統(tǒng)。
在最近一次對休閑越野車（SUV）車主的調(diào)查中，73％的車主表示他們希望自己的下一部車是全輪驅(qū)動型車，或四輪驅(qū)動型車。豪華車市場中50％的車主希望自己的客車或運(yùn)貨車卡車是全輪驅(qū)動的。
來自工業(yè)調(diào)查公司JD Power的一份近期報告預(yù)測，截至2008年，四輪驅(qū)動汽車將占到美國汽車市場的37％。預(yù)計基于前輪驅(qū)動車的AWD系統(tǒng)銷量的增加，將促成這一增長的到來，而AWD的市場份額在未來兩年內(nèi)，將達(dá)到現(xiàn)在的兩倍還要多，即從現(xiàn)在的13％增至32％。
看到SUV車銷量下滑，汽車制造商福特公司順勢而動，推出帶有全輪驅(qū)動的福特Fusion、水星Milan、林肯MKZ中型私家轎車、福特Egde和林肯MKX多功能交叉車?，F(xiàn)今，福特已有36種車型提供四輪驅(qū)動或全輪驅(qū)動。
與四輪驅(qū)動的手動啟動不同，AWD系統(tǒng)要么處于不停運(yùn)轉(zhuǎn)，要么不停地監(jiān)控汽車運(yùn)行情況并獨(dú)立啟動。對于駕駛者而言，車輪之間扭矩的交替改變幾乎是察覺不到的。
全輪驅(qū)動技術(shù)的優(yōu)點(diǎn)可以讓引工程師們在最佳牽引力下準(zhǔn)確地對某個或幾個車輪傳遞扭矩。
系統(tǒng)每秒對車況進(jìn)行100次監(jiān)測，分析運(yùn)行中車輪的實時狀況，駕駛員的動作如方向盤的轉(zhuǎn)動和踩油門的力度，然后相應(yīng)地變換扭矩并傳給車輪。
“全輪驅(qū)動的突出優(yōu)勢在于：可以靈活地傳遞扭矩并能對任一車輪進(jìn)行制動，”銷售經(jīng)理羅伯特·帕克說：“以前我們只能進(jìn)行從前到后或從后到前的扭矩傳遞，而先進(jìn)的全輪驅(qū)動技術(shù)讓我們可以在最佳牽引力下準(zhǔn)確地對某個或幾個車輪傳遞扭矩”。
在2007年車型使用的全輪驅(qū)動技術(shù)中，像Fusion和MXZ都是典型的前輪驅(qū)動模式。扭矩施加到前輪便于將車向前牽引。因為發(fā)動機(jī)位于車的前部——不論是向前牽引還是操縱方向，其重量都將提供給車輪更大的牽引力。
然而，當(dāng)系統(tǒng)測得牽引力不足時，它會將扭矩轉(zhuǎn)至任何一個或所有車輪。汽車在光滑路面上行駛時效果最為明顯，但其實AWD系統(tǒng)在許多不明顯的情況下提升著牽引力。
前輪驅(qū)動型汽車存在著比較普遍的問題是：轉(zhuǎn)向不足，轉(zhuǎn)彎時這一問題尢為突出。如果前輪驅(qū)動型車在轉(zhuǎn)彎時加速，汽車后部會突然承受過多重量，這將導(dǎo)致前輪牽引力不足。當(dāng)駕駛員想要打急轉(zhuǎn)彎時，汽車前輪會徑直沖向彎道外測。而全輪驅(qū)動系統(tǒng)則會通過調(diào)整施加于車輪的扭矩或改變發(fā)動機(jī)轉(zhuǎn)速或二者兼有之進(jìn)行自動補(bǔ)償。
自2007年伊始，預(yù)計配有AWD系統(tǒng)的汽車年銷售量約為50萬輛，其中的40萬輛將是轎車和功能交叉型車。聽起來這似乎是個大訂單，但福特方面表示，由于其正致力于令該技術(shù)讓消費(fèi)者更買得起，所以這個銷售目標(biāo)其實不難達(dá)到。
福特計劃銷售全輪驅(qū)動車型時的售價比其競爭者低3，100——5，400美元（合人民幣24，000——43，000元），在某種情況下還將降低部分前輪驅(qū)動型汽車價格。美國汽車工業(yè)的競爭將會達(dá)到新的激烈階段
車輛安全系統(tǒng)
沃爾沃公司采用主動安全和交互性更好的安全電子設(shè)備來增加駕駛員的安全感
幾乎每個人都擔(dān)心車的安全性。但對于一個跨國汽車公司來說，最重要的是要認(rèn)識到，造成這個問題的原因在各個國家是不相同的。瑞典的沃爾沃汽車公司在車輛安全性方面享有很高的聲譽(yù)。然而隨著各種車型紛紛提供最高級別的碰撞保護(hù)，這家汽車公司開始對影響買主安全感的其他因素進(jìn)行關(guān)注。該公司對一系列與車輛安全相關(guān)的預(yù)防性措施，包括主動安全系統(tǒng)和呼救系統(tǒng)進(jìn)行了研究。
過去，各汽車公司重視的是被動安全系統(tǒng)，即在發(fā)生事故時能為乘員提供保護(hù)的系統(tǒng)。現(xiàn)在，他們開始放寬眼界，“我們現(xiàn)在將注意力放在預(yù)警系統(tǒng)和防止事故發(fā)生的預(yù)防系統(tǒng)上”沃爾沃公司的安全問題負(fù)責(zé)人Ingrid Skogsmo說。
安全問題有三個要素：車輛本身、交通狀況和人。坐在方向盤后面的人仍然是最重要的安全因素，但與材料和結(jié)構(gòu)相比，電子設(shè)備顯得越來越重要。為了能在緊急情況下迅速做出決定，駕駛員必須時刻保持清醒并戰(zhàn)勝疲勞，但往往是說起來容易做起來難。
“研究表明，經(jīng)常在一輛車徑直撞入另一輛車的尾部時，后車駕駛員的腳還沒碰到剎車，”Skogsmo說。“這很可能是因為駕駛員根本沒有看到前方正在發(fā)生的情況，因而也就不可能防止事故的發(fā)生。我們開發(fā)的電子安全系統(tǒng)能在發(fā)生事故時為駕駛員贏得足夠的時間，讓他們能操縱車輛脫離險境”
交通繁忙的街道，駕駛中面臨的多種選擇和移動電話等都可能分散駕駛員的注意力。為了幫助駕駛確定什么信息是最重要的，可在車上采用一種能比人眼更快的速度判讀交通情況的先進(jìn)技術(shù)。主動安全系統(tǒng)能提醒駕駛員注意潛在的威脅，在關(guān)鍵情況下，當(dāng)駕駛員已經(jīng)來不及做出反應(yīng)，制止事故發(fā)生時，該系統(tǒng)甚至可以主動采取行動?！霸撓到y(tǒng)并不控制駕駛，而只是幫助駕駛員提高駕駛安全并使駕駛過程更愉快而已，”Skogsmo說。
沃爾沃公司已經(jīng)將其所開發(fā)的幾種主動安全技術(shù)投入了使用。該公司與2003年開發(fā)出了智能駕駛信息系統(tǒng)（Intelligent Driver Information System）。該系統(tǒng)能根據(jù)重要程度將對接收的各種信息進(jìn)行歸類，在需要駕駛員集中精力的情況下，能自動將電話、短信等不重要的信息接收推遲，其思路是在制動和超車等關(guān)鍵時刻防止駕駛員受到過多信息的干擾。
安全并不僅僅意味著防止事故的發(fā)生，然而，如果車子的安全等級高，駕駛員就更有安全感。任何可提升駕駛員安全感的措施都值得采用?！拔覀儗Υ撕苤匾暎必?fù)責(zé)沃爾沃市場情報的Karin Backlund說，“我們努力按照顧客的喜好對車輛進(jìn)行改進(jìn)，安全，包括人身安全，是沃爾沃公司的核心價值”
沃爾沃公司在9個國家發(fā)起了一項民意測驗，目的是對車主最擔(dān)心的安全問題進(jìn)行調(diào)查。各國得出的結(jié)論不一樣，瑞典人最擔(dān)心車輛在無人看護(hù)的情況下過夜，英國人對車上物品遭竊的擔(dān)心超過了車輛本身被盜，而大約一半的巴西車主則稱對盜竊并不關(guān)心，他們只關(guān)心自己的人身安全。
對“你最希望自己的車所具備的安全功能”的回答顯示出這種差異的原因。在巴西，汽車報警器沒有列入“5個最想擁有的安全功能”，而瑞典人則把它列排在第一條。巴西人和意大利人都希望擁有防撞夾層擋風(fēng)玻璃，而瑞典人則偏愛可鎖上的輪胎蓋。
有一項功能出現(xiàn)在所有國家的車主的“最想擁有”列表上，那就是：呼救系統(tǒng)?？磥硭袊业娜硕颊J(rèn)為呼叫警察和救護(hù)車的功能是很重要的。所有參與調(diào)查的人還一致希望能有幫助找回被偷車輛的技術(shù)。然而，這種技術(shù)的開發(fā)成本很高，除了對車進(jìn)行改裝以外，還需要許多其它的基礎(chǔ)設(shè)施，以確保能對車輛進(jìn)行跟蹤，而且應(yīng)急服務(wù)部門還必須知道如何對呼叫做出反應(yīng)。沃爾沃公司目前已經(jīng)在7個歐洲國家提供“呼叫”服務(wù)，并計劃將服務(wù)范圍擴(kuò)展到其他國家。
與此同時，該公司了在開發(fā)能使駕駛員在更遠(yuǎn)距離控制車輛的技術(shù)。該公司的S80型轎車將人車溝通系統(tǒng)（PCC）作為選裝件提供，但將來也可能作為標(biāo)準(zhǔn)配置，在所有車上都安裝。該系統(tǒng)的基本配置是一個可裝在口袋中的遙控系統(tǒng)，可在你扳動車門把手時自動為車輛解鎖。按下PCC的按鈕可以重新上鎖。
“駕駛員經(jīng)常會擔(dān)心車門是否鎖好”S80車的項目經(jīng)理Silvia Gullsdorf說，“往往走出幾米后，你還要把車鎖開關(guān)幾次才能放心”有了PCC你只需檢查鑰匙就能知道車是否已經(jīng)鎖好，你甚至都不必離車很近，鑰匙會顯示你最后一次操作是鎖車還是開鎖，你還可以不用鑰匙啟動車輛。
但無鑰匙進(jìn)車系統(tǒng)并不是最近才出現(xiàn)的。PCC系統(tǒng)的不同之處在于，你可以在60到100米外通過按下信息鍵來了解車子的安全狀態(tài)。不同的LED燈告訴你車是否上鎖，是否有人動過車子以及是否已經(jīng)發(fā)出警報等。水平儀可測出是否有人為了偷車輪將車子抬起。紅燈閃爍表明心跳傳感器被激活，說明車內(nèi)有人。
5
TTANSMISSION
Although modern automobile transmission used on automotive vehicles vary in details, they all in a similar manner. They have a torque converter and planetary-gear sets which are controlled by brakes and clutches to provide two or three forward gear ratios.
The transmission provides different gear ratios between the engine, since the engine produces little power at low speed . Thus, for accelerating the car from a standing start, considerable power is required; the engine should be running at a fairly high speed. The driver, therefore, shifts the transmission gears into first; this gear position permits the engine to run at a fairly high speed. A typical first-gear ratio would be that the engine develops high power, and the car moves away from the curb and accelerates quickly. Next, the driver shifts to second (momentarily declutching to permit moment of the gears in the transmission . In second, the car accelerates to a higher speed. In second, a typical ratio would be 8:1. Finally, the driver shifts to third. In this gear position, there is a direct drive through the transmission; the propeller shaft turns at the same speed as the engine crankshaft. In third, a typical ratio would be 1:1.there is another gear position, reverse. In this position, the propeller shaft is made to rotate in a reverse direction so that the car goes backward.
FOUR-WHEEL-DRIVE
In the USA, while more consumes are moving away from sport utility vehicles and opting for cars and crossovers, they still are not willing to part with all-wheel-drive systems. For them, it's a safety system.
In a recent survey of current SUV owners, 73 percent said they want all-wheel-drive on their next vehicle. In the luxury market, 50 percent of owners say they want all-wheel-drive on their cars or trucks.
A recent report from industry research firm JD Power forecasts that four-wheel-drive vehicles will make up 37 percent of all vehicles produced for the US by 2008.The growth is expected to come from increased sales of AWD systems based on front-wheel -drive vehicles. Their market share is expected to more than double to 32 percent from the current 13 percent in the next two years.
Seeing its SUV sales slipping away, carmaker Ford wants to be in a position to exploit this trend. The carmaker has introduced AWD versions of the Ford Fusion , the Mercury Milan and the Lincoln MKZ midsize sedans and the Ford Edge and Lincoln MKZ crossovers. Ford now has 36 vehicles that offer either four-wheel drive or AWD.
Unlike four-wheel-drive, which the drive must manually activate, an AWD system is either permanently on or it continuously monitors the vehicle's condition and takes action independently. To wheel is seamless.
The system monitors the vehicle's condition 100 times a second, analyzing what's happening with the wheels on the road, the drive's inputs such as turns of the steering wheel and the pressure on the accelerator. It then varies the torque sent to the wheels.
"A major advantage of all-wheel-drive is the flexibility to shift torque or apply raking to any wheel," says marketing manager Robert Parker." In the past we could either shift torque from back to front or from front to rear. With advances in AWD technology, we can shift torque to the exact wheel or wheels with the best traction
In the AWD technology for he 2007 models, a vehicle like the Fusion or MXZ is typically front-wheel-drive. Torque goes to the front wheels in effect pulling the vehicle along. Because the engine rests over the front of the vehicle, the weight provides greater traction to the wheels both pulling and steering the car.
If, however, the system senses a loss of traction it shifts torque to any or all of the wheels. The most obvious benefit occurs on slippery road conditions, but the AWD system improves traction in a number of less obvious situations.
A common problem with front-wheel-drive vehicles is their under steer, typically seen in cornering. If a front-wheel-drive vehicle accelerates into a turn, too much weight can be shifted to the rear, causing loss of traction in the front wheels. The front of the vehicle can go towards the outside of the turn when the driver is aiming to turn the car sharply. AWD automatically compensates either by adjusting the torque to the wheels, altering engine speed or both.
Starting in 2007, Ford expects to sell around 500000 AWD-equipped vehicles annually, of which 400000 will be cars and crossovers. It sounds like a tall order, but Ford says the numbers should be easy to reach, as it is making the technology more affordable.
It plans to sell AWD models for between USD 3100and 5400 less than competitors, in some cases undercutting the prices for their front-wheel-drive models. Competition in the US industry is about to reach a new level of intensity.
SAFETY AND SECURITY
Almost everybody worries about car safety issues. But for an international carmaker it is important to recognise that the reasons for this concern differ from country to country. Swedish carmaker Volvo has established a strong reputation for vehicle safety. But with so many vehicles now offering the highest levels of crash protection, the carmaker is looking at other factors that will make buyers feel safe and secure in their car. The carmaker is looking at a range of preventive vehicle safety and security measures including active safety and "Mayday" systems. In the past carmakers have focused on passive safety, meaning systems and functions that help protect people in the event of an accident. Manufacturers are now broadening their outlook. "We are focusing on technologies that predict and prevent accidents from even occurring, "says lngrid Skogsmo, Volvo's safety director. Safety has three main perspectives: the car, the traffic situation and the human being. The person behind the wheel is still the most important factor, but the electronics are becoming more important than the materials and construction. The driver must stay alert, be able to make quick decisions in stressful situations and not give in to fatigue. But this is often easier said than done.
"Research shows us that often when a car ploughs straight into the rear of another car, the driver never even hits the brakes," says Skogsmo." This is probably because the driver never saw what was going to happen, and so had no chance to prevent the accident. Our electronic safety systems are developed to prevent the accident. Our electronic safety systems are developed to help increase the time the driver has to manoeuvre the car out of danger."
Busy streets, multiple choices and mobile phones all compete with the driver's attention. To help the driver decide which information is more important, vehicles can be equipped with advanced technology that reads traffic quicker than the human eye. The active safety systems warn about threats, and can even step in and act in critical situations if there is not enough time for the driver to avoid them." The system doesn't take over the driving, it just helps the driver to increase safety and make the driving experience more enjoyable," says Skogsmo.
Several developed active safety systems are already in use at Volvo. The firm introduced an Intelligent Driver Information System in 2003. The system sorts incoming information according to relevance and delays phone calls, text message and other non-critical information in situations that demand the driver's full attention. The idea is to prevent the driver from suffering information overload during braking or overtaking.
Safety is not just a matter of avoiding accidents, however. Having a vehicle with a good safety rating makes drivers feel secure. Anything that can contribute to this is a worthwhile addition." We treat this seriously," says Karin Backlund, responsible for Volvo's market intelligence." We try to adapt our customers' preferences. Safety is a Volvo core value and that has to include personal security."
Volvo carried out a survey in nine countries to find out the situations that concern car owners the most. Differences between countries emerged. Swedes are particularly worried about leaving their cars unattended overnight, while the British about leaving their cars unattended overnight, while the British are more concerned about break-ins and the theft of property rather than theft of the vehicle itself. About half of Brazilians, on the other hand, report that they are not concerned about this aspect, focusing exclusively on personal security.
The reasons for anxiety are reflected in the security enhancing features that the respondents would like to have in their cars. In Brazil, a car alarm was mot among the five most wanted security features in the survey, whereas this was top of the list in Sweden. Brazilians and ltalians wanted impact-resistant laminated windscreens, while Swedes preferred lockable wheel trim.
One thing appeared on all wish lists: a Mayday system. People of all countries considered it important to be able to call the police or an ambulance .All of the respondents also agreed that they want to see technologies that assist the recovery of a stolen car. Such systems are costly to develop, however. They require an extensive infrastructure beyond the car to ensure that the vehicle can be tracked and that the emergency services know how to respond to the call. So far, Volvo has launched its" on call" service in seven European countries and plans to add more.
In the meantime, the firm is exploring technologies that give drivers more remote control of their vehicle. The Personal Car Communicator is being offered as an optional in all cars.It's basically a pocket-sized remote control. The device is used to unlock the car door automatically when you pull the door handle. Pressing a button on the PPC can also lock it.
"Wondering if the car is locked is a frequent worry among drivers," says S80 project manager Solvia Gullsdorf." You walk a few metres and then have to check by unlocking and relocking the car" With the PCC, you simply check the key to see if the car is locked. And you do not even have to be near the car; the key just indicates whether your last action was to lock or unlock. It also allows you to start the car without a key.
But keyless entry systems are hardly new. What makes the PCC different is that at a range of 60 to 100m, you can obtain a security status report by pressing the information button. Different LEDs tell you if the car is locked or unlocked, others whether somebody has interfered with the vehicle and caused the alarm to go off. A level meter detects if the car is raised in an attempt to steal the wheels. A flashing red light means that the heartbeat sensor has been activated and that there is an intruder in the car.
"We know that motorists in many countries are fearful of assault, whether going to and from the car in dark and unsupervised parking places , or by somebody who has hidden in the car," says Gullsdorf. However, the darkness can be eliminated. Just one press on the remote control can switch on the car in a dark parking area.
When leaving the car, the headlights can also be switched on for up to 90 seconds by operating the headlamp flasher, allowing you time to get to your front door. The car alarm is activated if somebody.
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