ME C8 DCT Patent Found, No Surprise Again By Jeremy Welborn (“jagamajajaran”)

[John]

GM filed this patent for the dual clutch transmission back on November 13, 2015, though just granted June 4, 2019 — though note the “prior publication date of May 18, 2017. Here are the patent’s details. Thank you Jag for again being the ME’s patent super sleuth.



Source, with thanks: http://www.uspto.com/

[John]

Reserved.

[John]

[John]

[Shrike6]

TL / DR
JK...a plurality of gears

[Plasboy]

So maybe an in-house transmission rather than Tremec etc.?

[ZORA 69]

At this age I don't want to know how the watch is built. I just want to DRIVE IT.

[455SDguy]

My first quick read there is mention of a 10-speed DCT variant of the 8-speed DCT. That is interesting stuff. Thanks Jag.

[Sigmon]

So maybe an in-house transmission rather than Tremec etc.?

While I'm still hoping for a ZF unit, I'd be fine with it if it's more like the 10AT and less like the 8AT.

[Bikerjulio]

It would be nice if a clever transmission expert explained what was different about this design in order to make it patentable.

[meyerweb]

I would be nice if a clever transmission expert explained what was different about this design in order to make it patentable.

Exactly what I was thinking.

But the PTO these days grants patents to almost everything, and relies on the courts to sort things out if someone objects. They gave up their job of actually vetting patents years ago. I guess that's the result of an ever growing number of patent applications and budget and staffing cuts for PTO.

[Shrike6]

I’ll guess that this means that this will be the transmission for the ME, built by Tremec, most likely. And would eliminate the ZF unit as a possibility.
Also, if things go as planned, this may be the last actual transmission designed, due to electric vehicles not needing one.

[Bikerjulio]

Will be interesting to see if this is the Tremec trans or not. The engineers probably patent everything they come up with as a routine, so not necessarily the trans for the C8.

So skimming the text and drawings, a couple of things jump out.

The author contends that this trans design uses fewer gears for the same number of ratios than a conventional design, and is therefore lighter and more compact.

The schematic drawings show a transaxle layout, rather than a straight through design. Interesting..........

Other than that I'd still need some expert advice to figure it out.

[SheepDog]

Koenigsegg Jesko has a smaller lighter DTC with 3 or 4 shafts. Smaller. Less space. Sounds similar, maybe.

https://www.roadandtrack.com/car-shows/geneva.../koenigsegg-gearbox-explanation

[rlhmarines]

DCT patent for 3 versions of the 8 speed, a 9 speed and also a 10 speed from what the document described. Cool.