The CPC stack on GM's grant US11167643B2 (issued November 9, 2021) — B60L 3/0046 (electrical fault monitoring), B60L 15/20 (controlling speed/torque), B60L 58/12 (battery state of charge), and B60L 58/26 (battery thermal management) — reads like a checklist of everything that goes wrong when you flat-tow an EV. Flat-towing spins the traction motor through the road wheels, turning the motor into a generator whether or not anyone wants it to. The claim is a decision tree for managing that involuntary generation, and its structure is the invention.

“Presented are intelligent vehicles and control logic for provisioning comprehensive tow features, methods for manufacturing/operating such vehicles, and electric-drive vehicles with tow features for protecting the vehicle's powertrain and electrical components during towing.”— U.S. Patent No. 11,167,643 source

Independent claim 1 walks a controller through a sequence of gates. First it "receiv[es]... an electronic tow signal indicating initiation of a towing operation." Then it checks "whether or not a drive system failure exists, the drive system failure preventing the traction motor from electrically connecting with the traction battery pack." That fault check is the safety interlock — if the inverter or contactors can't safely close, the controller must not try to connect a spinning motor to the pack. Only if there is no failure does it reach the central test: "whether or not a towed motor speed of the traction motor during the towing operation... exceeds a calibrated base speed."

That base-speed comparison is the load-bearing limitation, and it maps to real machine physics. A permanent-magnet traction motor produces back-EMF proportional to speed; below a "base speed" the back-EMF is low and connecting it to the pack does little useful work while risking uncontrolled current, while above base speed the motor is generating enough that the inverter can manage it as controlled regeneration. So the claim's rule is precise: "responsive to a determination that the towed motor speed exceeds the calibrated base speed, [transmit] a connect command signal to the power inverter to electrically connect the traction motor to the power electronics and/or the traction battery pack," and below it, "[transmit] a disconnect command signal... to electrically disconnect." The controller connects to harvest above base speed and isolates below it — protecting the powertrain across the towing speed range rather than picking one static state.

The dependents are where GM hardens the claim into a usable protocol. Claim 2 specifies that the connect command "includes: a short signal shorting the traction motor into multi-phase operation via the power inverter; and a cool signal initiating a thermal protection protocol cooling the traction battery pack via a pack cooling system." Active three-phase shorting is the standard way to bleed off a high-speed PM machine safely, and pairing it with pack cooling acknowledges that harvested tow energy heats the battery — which is exactly why B60L 58/26 is on the patent. Claim 3 defines the disconnect command as "multiple open circuit signals opening a plurality of solid-state relay switches of the power inverter," naming the inverter switches as the disconnect mechanism.

Claims 4–9 layer in state-of-charge logic, tying the abstract "connect" decision to whether the pack can actually accept or supply energy. Claim 4 initiates "regenerative charging of the traction battery pack via the traction motor during the towing operation"; claim 5 gates that charging on "a pack state of charge (SOC)... less than a calibrated SOC threshold"; claim 6 caps it at "a calibrated maximum power input level." The mirror image appears in claim 7, which initiates "a torque assist output via the traction motor," gated by claim 8 on SOC exceeding a threshold. Claim 9 makes the controller warn the driver when neither is available — no regen if the pack is full, no torque assist if it is depleted. This is a genuinely complete energy-management state machine, not a single rule.

The human-factors dependents round it out. Claims 10–12 handle the failure branch: on a drive-system fault the controller either commands the inverter open, prompts a manual electrical disconnect, or prompts a mechanical disconnect of the motor from the road wheels — three escalating fallbacks. Claim 13 surfaces an HMI choice between "an active tow control mode and a passive tow control mode," and claim 14 ties passive mode to a thermal-protection cool signal. Claim 15 re-casts the whole method as an electric-drive vehicle, and claims 16–20 repeat the connect/disconnect, shorting, SOC-warning logic in apparatus form, so the protection is claimed both as a method and as the vehicle that runs it.

A note on why the base-speed gate matters mechanically is warranted, because it is the difference between a protective design and a damaging one. Flat-towing forces the permanent-magnet rotor to spin at road speed; its back-EMF rises with that speed regardless of driver intent. If the inverter contactors are closed below base speed, the machine cannot do controlled regeneration and the system risks circulating current with little benefit; if they are open above base speed, the rising back-EMF has nowhere to go and can stress the open inverter. The calibrated base speed is the crossover where connecting becomes the safer state, which is why claim 1 makes the connect/disconnect decision turn on it rather than on a fixed rule. The active-short of claim 2 is the recognized fallback for shedding a high-speed PM machine's energy across all three phases, and pairing it with pack cooling in the same command acknowledges that any harvested or shorted energy lands as heat in the battery — the reason B60L 58/26 (thermal management) sits on the patent at all. The SOC dependents then ensure the harvested energy is only pushed into a pack that can take it, capped at a calibrated input level, which is what keeps an unattended tow from overcharging or overheating the battery.

The verdict: enabling, examined, and unusually concrete for a "towing" patent. The novelty is the base-speed-gated connect/disconnect decision wrapped in SOC-aware regen-and-assist logic and a multi-stage fault fallback. The CPC checklist is honest here — fault monitoring, torque control, SOC, and thermal management all appear as actual claim limitations. Read the moat in claim 1's base-speed gate and the SOC dependents (claims 4–9), and treat the broad abstract framing about "comprehensive tow features" as the wrapper, not the substance.