It Sure Looks Like GM Is Copying Lucid’s Homework

Lucid Motors builds essentially the most environment friendly electrical autos on the earth, and the remainder of the auto trade desires a chunk of that effectivity. Some, like Aston Martin, see match to easily buy the automaker’s tech. Others wish to develop it for themselves. A type of firms seems to be Basic Motors, which not too long ago utilized for a patent on a compact electrical drive unit that makes use of one in all Lucid’s key architectural options: the differential-in-rotor design.

For these unfamiliar, Lucid pioneered a novel structural method to constructing compact and environment friendly electrical drive models. Generally, an electrical motor consists of an out of doors stator and an inside rotor, the latter of which spins. Many electrical autos have strong rotors, however the inside this construction doesn’t truly produce a lot torque. Lucid miniaturized its drive unit by making the rotor donut-shaped and placing the differential inside. Because it doesn’t expertise wheel torque immediately, this diff could be a lot smaller, lighter, and extra environment friendly. This tiny differential drives two coaxial planetary gearsets, which drive the wheels. The 49:30 mark on this video from Lucid explains this very good innovation higher than I can by way of textual content:

Basic Motors’ patent utility takes this core differential idea and applies it to a barely completely different system. Curiously, the automaker is cagey within the doc about explicitly saying it’s placing a small differential inside the rotor. The truth is, the three-dimensional drawings supplied with the patent omit each the electrical motor and differential utterly. The 2-dimensional illustrations supplied with the patent make it clear that’s what’s happening, although. 

The one actual trace within the doc textual content that the differential sits contained in the rotor occurs close to the tip of the patent, the place it’s acknowledged that it sits “upstream” from the remainder of the geartrain. Aside from that, no different point out of the differential or rotor within the textual content describes their nested nature. 

To be clear, there are a number of variations between Lucid’s drive unit and the one described in GM’s patent. The primary massive distinction is that GM’s unit will not be coaxial. The rotor, intermediate discount gears, and axle outputs are all on completely different axes. GM’s unit is likewise a locking differential. This implies it might be utilized in a efficiency or off-road setting the place locking the diff could be advantageous. Lucid’s electrical drive models should not have a mechanical locking function, though the corporate’s dual-motor drive models supply advanced torque vectoring.

The crux of the patent is that this new design could be compact and intensely environment friendly, which is of course the identical idea Lucid is chasing. The doc claims that “In sure embodiments, the drive unit structure described herein gives for as much as 95% effectivity.” That’s very spectacular, if its true. 

Till such a drive unit is launched—that is only a patent, in spite of everything—we gained’t know if GM truly plans to do something with this design. It’s an interesting unit on paper, if not fairly so theoretically compact as Lucid’s, and chasing effectivity is every part for automakers constructing EVs.