If you want to find the gap between an EV's brochure and its reality, hitch a trailer to it. Range figures assume an empty hitch and gentle driving. Towing doubles or triples the energy needed to move the vehicle, draws sustained high current from the battery, and pushes the motor and inverter toward their thermal limits — all the conditions a marketing range number quietly excludes. Towing is the EV powertrain's hardest routine test.
The record: on November 9, 2021, GM Global Technology Operations LLC was granted US11167643B2, “Electric-drive vehicles, powertrains, and logic for comprehensive vehicle control during towing.” The CPC classes are powertrain-and-battery control — B60L 15/20 (electric-propulsion control), B60L 58/12 and 58/26 (battery management), and B60L 3/0046 (fault monitoring), plus trip-recording classes G07C 5/0808. This is control logic for the towing case.
Here is what changes when you tow. The powertrain has to deliver far more sustained torque, which means more current, which means more heat in the motor, inverter, and pack. The battery drains faster, so range planning has to account for the load. Regenerative braking behaves differently with a heavy trailer pushing from behind. A control system that treats a towing EV like an unloaded one will either overheat, mis-estimate range, or brake poorly.
The way comprehensive towing control works conceptually: the logic recognizes the towing condition and adapts — managing thermal limits proactively, recalculating range against the real load, tuning torque delivery and regeneration for the trailer's mass and dynamics. It is the powertrain acknowledging that it is hauling and behaving accordingly, rather than discovering the limits the hard way mid-grade.
Trace it to the product and the significance is credibility. Pickups and SUVs are where the volume and margin are, and those buyers tow. An EV that loses most of its range or overheats with a trailer is not a serious truck. Patenting comprehensive towing control is GM staking out the engineering needed to make an electric truck actually work as a truck — which is a higher bar than making it work as a commuter.
The caveat: this is a granted control-logic method, not a measured towing-range figure, and “comprehensive” is the patent's word, not a verified outcome. But it points at the right truth. Follow the kilowatt-hours under load and you find the real test of an EV powertrain. The interesting number is never the empty-hitch range — it is what happens when you put two tons behind it.