沙发,总算贴完了...
抱怨一下,xcar 每贴10000字符限制,不能所见即所得引用照片,也不能批量上传照片,只能一张张编辑上传,实在是太麻烦了!!! 严重打击发作业的积极性啊,哪怕是转载的,好东西就该共享.
点评完.
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看大家对4MOTION有兴趣,补一片VW官方的说明....
http://media.vw.com/article_display.cfm?article_id=9754
VW 4MOTION®
All-Wheel Drive, All the Time
LAS VEGAS, Nev. – Volkswagen’s GTI essentially created and defined theperformance sports hatch/sports coupe segment that today is populatedwith the likes of the Mazda3, Chevy Cobalt, Honda Civic and FordFocus. That original GTI was the first pocket rocket, the mating of apowerful engine to a lightweight sedan chassis. In 2004 VW upped theante with the R32, one of the most powerful VW models to date, thanksto a new and highly responsive 240-bhp 3.2-liter V6 engine. With20-percent more power and 20-percent more tire-smoking torque lurkingunder the hood, Volkswagen engineers realized that it was time to notonly talk the torque but to split the torque…to both axles, instead ofleaving it all up front.
Enter 4MOTION, VW’s all-wheel-drive system which ensures that every bitof power is efficiently distributed to all four tire patches, assistingthe R32 in the areas of stabilization, traction and balancedhandling. Fun to drive? You bet.
Before delving too deeply into 4MOTION, understand that there are twodifferent versions, one for VW models equipped with longitudinaldrivetrains, such as the Phaeton and Touareg, and another for those VWmodels with transverse engines, including Jetta and Passat. Phaetonand Touareg models use a Torsen center differential to control anddeliver power to all four wheels. However, the transverse drivers areequipped with a high-performance Haldex clutch at the rear axle toaccomplish the same task. And it is the latter system that we willconcentrate on here. This is actually the second-generation 4MOTION;an earlier version was introduced on the Golf in some markets (but notthe U.S.) in 1998. This new-generation all-wheel-drive system has beenimproved in many aspects. For example, the Haldex clutch unit mounteddirectly on the rear axle is now significantly more compact.
The most important technical element of 4MOTION is the latestgeneration wet-running (oil bath) Haldex multi-disc clutch. Comparedto a straightforward mechanical Torsen® differential, the Haldex unitoffers the significant advantage that it can be electronicallycontrolled. As a result, it integrates perfectly with the Anti-lockBrake System (ABS), traction control Anti-Slip Regulation (ASR), theElectronic Differential Lock (EDL), and the Electronic StabilizationProgram (ESP).
As soon as there’s any difference in the rotation speeds of the frontand rear axles, two pumps located within the multi-disc clutch areactivated. These build up pressure in the transmission unit andthereby “link together” the two axles. They only take effect when theinput and output shafts of the transmission unit are no longer turningat the same speed because only then is torque splitting necessary.
Altering the pressure exerted on the clutch discs can vary the amountof torque transmitted. This makes it possible to control the powerflow between the front and rear wheels. The transmission unit performsinfinitely variable torque control from zero up to full transmission –a 50:50 split of the propulsion power between the front and rear wheels.
When the car is driving straight ahead and there’s no difference ingrip between the wheels, 90 percent of the power is sent to the frontaxle and 10 percent to the rear. The only thing the driver reallynotices is that any VW model equipped with 4MOTION retains neutralhandling characteristics and stays on course in practically anysituation.
The Haldex coupling is mounted on the rear axle differential and isdriven by the drive shaft. The electronic control unit for the Haldexclutch unit gets all the important drive and engine information via theCAN (Controller Area Network) bus. This includes signals from thewheel sensors, the ABS and ESP as well as information about theaccelerator pedal position and engine revs. This data provides theengine control module with all the information it needs on road speed,cornering, coasting or traction mode, allowing the system tocontinually monitor and regulate the level of hydraulic pressure torespond optimally to any driving condition.
Commands from the electronic control unit are carried out very rapidlyby the Haldex unit. Full pressure is applied after a rotation angle ofonly 45 degrees of the first revolution after the Haldex receives anelectronic signal. This generates the corresponding torque at the rearaxle.
What about side-to-side slippage? This is when the ElectronicDifferential Lock comes into action to control traction. Think of thisas ABS in reverse because EDL uses the same sensors and components asthe ABS but to control “acceleration” instead of “braking” slip.
The speed sensors at each wheel continually send information to the ABScontrol module. When there is a difference in wheel speeds, the EDLfunction applies the brakes to the wheel that is spinning to controlslip. When brakes are applied to the wheel that is spinning, powerwill automatically be sent through the differential to the wheel thathas traction. For example, if the vehicle is on a patch of ice andonly one wheel has traction, EDL will pump the brakes of the threewheels that are spinning.
Some of the system’s important characteristics include compatibilitywith different size tires, quick response and no strain on themulti-plate clutch when parking and maneuvering.
Traction off the line is aided by the Haldex coupling, which directspower to the rear wheels when it detects the front pair slipping.
You’ll also experience the benefits of 4MOTION the moment you attemptto accelerate on wet or slippery pavement. In a front-wheel-drivevehicle, the car will attempt to spin its front wheels. But before itcan do this, the car’s traction control system will intervene, applyingthe brakes and adjusting the throttle opening. The net effect is thatyou’ll accelerate at a rather modest rate. 4MOTION response isdecidedly different.
Transferring torque to those tires with the most traction results indramatically quicker acceleration. The only time the traction controlwill intrude significantly is on an extremely slippery surface such asice.
Drivers will really appreciate the precise manner in which a4MOTION-equipped VW corners and steers. Torque steer iseliminated. Absolutely gone. The first time you accelerate hardthrough an uphill hairpin bend with a lot of steering cranked on andexperience the ease with which the VW model grips the pavement. With4MOTION, power can be transmitted variably to all four wheels usingelectronic control. This means each wheel always gets the appropriateamount of power for the available grip.
Founded in 1955, Volkswagen of America, Inc. is headquartered in AuburnHills, Michigan. It is a subsidiary of Volkswagen AG, headquartered inWolfsburg, Germany. Volkswagen is one of the world’s largest producersof passenger cars and Europe’s largest automaker. Volkswagen ofAmerica and its affiliates employ approximately 3,000 people in theUnited States and are responsible for the sale and service of Audi,Bentley, and Volkswagen products through retail networks comprising intotal more than 900 independent U.S. dealers.
"Volkswagen" and "4MOTION" are registered trademarks of VolkswagenAG. "DSG" is a trademark of Volkswagen AG. All other trademarks usedin this document are the property of their respective owners.
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本帖最后由 猩魔 于 09-04-14 16:30 编辑 ]
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