Audi and BMW to utilize 8-speed gearboxes to take on Lexus

[Wolfgang]

BMW stuck a picture of this transmission onto their server:



From:

BMW EfficientDynamics : BMW Concept X6 ActiveHybrid : The energy management

[coolraoul]

Originally Posted by Wolfgang

Hello coolraoul,

I found another Mercedes sales prospectus mentioning an 8 speed transmission. Does this one count?

From the MBUSA 2010 ML450 HYBRID sales brochure:

"The ML 450 HYBRID’s CVT — Continuously

Variable Transmission — optimizes power
and efficiency seamlessly at all speeds,

and offers an 8-speed manual shift mode."

Source: http://www.mbusa.com/mercedes/data/p...10-M-Class.pdf

Hi Wolfgang!

Nice try, but... Well, no, it doesn't count actually...
I'm sorry...

What is complex is to make the chip choose the right gear at the right moment. Not too soon, not too late. And to do so with comfort, reactivity, economy, motorbraking in mind.
And of course, the more gears you have, the more complex it is!!!

Here, for the hybrid ML... Because it's a CVT, it doesn't really feature 8 gears. A CVT has no fixed gears, it continuously adapts the revs to the situation. Therefore, the electronics don't deal with 8 gears.

The 8 gears the brochure speaks about are artificial gears that are created specificly for the manual mode.

These 8 gears are only there in manual mode, when the gearbox is in automatic mode it doesn't materially change gears at all in fact.

So the chip doesn't need to choose between 8 gears. It just changes the ratio according to the needs... It's only when you put it in manual mode that the system "creates" 8 different, artificial ratios you can choose from.

Think about it like that: in automatic, it's like a wheel to control the volume of the radio. You turn it just as you want, there are no fixed intervals.
In manual, it's a + and a - button: you have fixed intervals.