GM Files Patent For Tow Assist System

What is this thing and how does it work? Could it reduce EV range loss while towing an RV trailer?

I’ve actually discussed this type a tow booster system with a developer a few years ago. So I understand its potential as well as the pitfalls of this design.

Hey, Lucy!

Looks a little like something from the Long, Long Trailer movie. This was an early non-powered tow dolly that was designed to allow you to tow heavy trailers with passenger cars. You could buy this gadget back in the ‘40s and ‘50s, before there were a lot of dedicated tow vehicles.

Now, I think this vintage SlimpWheel coupler could be very dangerous since it doesn’t provide any braking action, nor does it assist with pulling the trailer down the road. But it certainly helped keep the passenger car from squatting down due to the tongue weight of the trailer.

Fast Forward to 2023

Now we would like to be able to tow an RV trailer with an EV truck or SUV. And the big problem is the drop in driving range. As has been reported by many car magazines, myself included, the EV range loss while towing can exceed 75%. So instead of a 250 mile driving range, you might only be able to drive 75 miles on a battery charge while towing your trailer. Yikes!

What if someone built a tow dolly that had traction motors/generators in the wheels and a big battery pack that would help pull the trailer at highway speeds, a regenerative braking system, as well as intelligent sway control to keep you in your lane? Could this be an interim solution that would turn a lot of new EV owners happy campers.

From GM Authority

Read the original article here

GM has filed a patent application for a new tow assist system capable of providing a vehicle with greater towing capacity.

The GM patent filing has been assigned application number US 11,607,918 B2 with the United States Patent and Trademark Office (USPTO) and was published on March 21st, 2023. The patent was originally filed on October 21st, 2019, and lists several Canadian-based engineers as the inventors, including Avesta Goodarzi, Ralph D. Schlottke, Grant L. Meade, and Norman J. Weigert.

A GM patent image describing a tow assist system.

The patent describes a tow assist system that is coupled between a lead vehicle and a trailer. The system incorporates a drive unit that will respond to a force between the trailer and tow assist unit, bearing a portion of the force required to tow the trailer.

As the patent points out, vehicles are typically purchased for a variety of different uses, with towing usually relegated to only occasional use. In addition, some users may own a variety of different trailers that offer a range of different weight capacities. Purchasing a vehicle with a high towing weight capacity may be undesirable due to both vehicle expense and operating expense.

As such, a flexible system whereby a vehicle with a relatively low towing capacity can be enhanced to offer a relatively how towing capacity could provide the perfect solution for some users. The patent describes a system that incorporates an inertial measurement unit and controller that is configured to actuate the drive unit in response to inputs, providing additional towing force as well as affecting overall trajectory to provide greater stability, the latter of which is particularly important for very heavy weights and towing in a series of three units (also known as triple towing).

Finally, this system also incorporates the means by which the tow assist unit can supply electrical power from the onboard battery pack to the trailer through an inverter, as well as provide braking as needed for added stability.

What do you think?

I’m going to try to find out more about this powered tow dolly, and will do a future report. But the basic concept is sound, and it really should work. However, this isn’t going to be cheap, especially for early adopters. We shall see…

Update: Ford EV tow-charging system

Ford filed a patent in 2020 for an EV road train. I’ll cover this in a future article, but it proposes to to tow a train of EVs behind a big truck to charge them with regenerative braking. While I don’t think a EV tow-train will ever be practical, I do like the idea a slow-charging a single TOAD behind your gas or diesel Class-A RV.

In the meantime, please leave your comments below.