Experimental Transmission Aims To Tackle The Biggest Problems With Hybrids

Plug-in hybrid vehicles, better known as PHEVs, are rather infamous for two things: mechanical and reliability issues, and how much they cost. These are expensive and complicated cars to produce because of what they are — think about it. You're buying a car with effectively two propulsion systems on board, those being a typical internal combustion engine and an electric motor. The engine needs its own fuel system, transmission, mechanical linkages to the driveline, and so on. Meanwhile, the EV portion needs a battery and all its own hardware. Then you need all the sensors and technology to get the two to cooperate. In short, it's a bit of a nightmare to fit into a car.

One company aims to change that, at least a little bit — Faraday Future. You can't really do much about the powertrain complication with a PHEV, since it still needs both a combustion engine and a sizable motor. But you can work on making these two systems cooperate in an uncomplicated manner, which is Faraday Future's pitch: imagine a new, simpler, more robust transmission that links these two together in such a way that it can decouple one or the other.

Okay, that's a bit confusing, so let's simplify it to a single sentence. Faraday Future has patented a proof-of-concept transmission called the "Range-Extending Hybrid Transmission System," which allows either the engine or the electric motor to operate concurrently or independently. It'll supposedly accomplish this through a series of clutches and shafts, which, the company claims in its press release, will improve range and simplify the mechanical complexity inherent in hybrid technologies. How much of that is true versus corporate-speak, though? Let's dive in and break it down.

First things first: How on Earth will this thing supposedly work? Marrying an electric and combustion powertrain isn't trivial — just look at any diagram of an eCVT-equipped Toyota PHEV if you want a newfound respect for the poor mechanics who have to work on them. Simplification is certainly welcome, and Faraday Future hopes to accomplish it through what it calls a "Multi-clutch and multi-shaft architecture."

What does that mean? Okay, you know how a typical 4x4 has a transfer case leading to the front and rear wheels via two separate shafts? It's like that. Imagine you have this big "transfer case" in the middle of the car. It features two shafts extending from it. The first shaft connects to the engine, a second shaft links to the electric generator-motor, and the third shaft runs to the driven wheels. Each of these shafts has its own multi-plate clutches, operating like independent DCTs. This theoretically allows you to disconnect one or more shafts at once, then mesh them back in sync with one another like shifting gears in a manual transmission.

Why clutches, though? Well, let's say you're running the electric motor at a certain speed, and now the computer's telling the car to engage the combustion engine. The clutch will rub against the spinning shaft, synchronizing the engine shaft's speed with the output shaft's speed. It can theoretically do this with the electric motor as well — basically, it lets you decouple one or all of the shafts, since they all have these clutches. Faraday Future is billing this system as part of a larger "AI Hybrid Extended-Range" software suite, touted to be an AI-enhanced driving package.

The whole point of a PHEV is to combine the functionality of both an EV and a combustion engine in one car, allowing you to commute as an EV or go further afield with the flexibility of fossil fuel. Combining these two elements in a compact package is already costly and complicated. Adding in no fewer than three shafts and however many clutches (the current patent calls for four) sounds far less efficient in both space and mechanical complexity.

That said, even a quick glance at the patent — U.S. Patent No. 12,630,004 — shows it's still a proof of concept at best, so it'll likely be years before any working prototypes are actually fitted to cars. There are a number of hurdles to overcome if Faraday Future wants to deliver on its promises of simplicity and reliability, but that doesn't mean it's impossible.

Take the driveshafts and clutches as one example. As a reminder, this system must fit in a car with a medium-capacity battery pack, an electric motor, a combustion engine, and a fuel system on board as well. All the sensors, linkages, and mechanical components needed to operate the clutches will take up precious space, and the shafts will need their own tunnels. That's a lot of real estate versus an eCVT, and that's only the tip of the iceberg when it comes to all those moving parts and electronics.

There's only so much leeway that buzzwords like "AI-Enhanced" can deliver in terms of tangible benefits over proven systems like Toyota's long-standing hybrid programs, among other reliable PHEV models, so we remain skeptical of Faraday's claims until proven otherwise. Nevertheless, we acknowledge the need to simplify these incredibly complex vehicles and applaud anyone taking a stab at innovative concepts.