主题：【原创】自动挡和手动挡那个更省油？ -- Highway

喜欢。觉得Multitronic生猛不足，不如手挡“脆”，不如手挡“爽”。

现在大众/奥迪最牛的Transmission是所谓的DSG(Direct Shift Gearbox )，从技术上讲，可能是自动/手动的最佳组合了。

So, let's get technical. . . 

The box uses three shafts, but the secret (well, not really a secret but kept well hidden since 1940) is contained in the use of two clutches and two rows of gear ratios ?C 1, 3 and 5 on one shaft and 2, 4, and six on the other.

Throughout its operation two adjacent gears, one on each shaft (say 2 and 3), are meshed and turning but, as each shaft has its own clutch, only one is transmitting power to the final drive.

In essence, second gear is driving the car while third is pre-selected. When either the auto or manual shift does its job one multiplate clutch is instantly disengaged and the other takes the drive with the intervention of electro-hydraulic control.

The same thing happens during downshifts; so, you're not so much changing gear as swopping clutches. There is, Audi says, some overlap but slippage is anticipated and controlled.

In automatic mode, the driver can shift to the ultra-sporty 'S' programme in which upshifts are significantly retarded, downshifts advanced and the shifting process accelerated.

[IMGA]http://www.fast-autos.com/Assets/golftdi-dsg.jpg[/IMGA]

A remote, one-touch function accessed via the shift paddles on the steering wheel in addition temporarily calls up the manual mode, even in automatic modes D and S.

And a final touch to what is already a superb gearbox: the car comes with Formula 1-style launch control. It works like this. . .


While stationary, deactivate the traction control system that would normally reduce engine power as soon as a wheel starts to spin and slow the car.

Hold down the footbrake and simultaneously increase engine speed.

When the lights change, lift off the brake and press the accelerator hard.

All four wheels bite the tar and suddenly all other traffic is shrinking in the rearview mirror.

Hey, is this fun or what!