A recent Ford patent filing hints that the automaker is considering a line lock for all-wheel drive vehicles.
Ford began offering a line lock on the Mustang for the 2015 model year. In rear-wheel drive vehicles, it locks the front brakes, allowing the rear wheels to spin freely while the car remains stationary. In drag racing, this is helpful for doing burnouts to warm up the tires before staging at the starting line, but it also provides an easy way to smoke the tires on any occasion.
2015 Ford Mustang electronic line lock
Because it relies on locking one set of brakes, thus preventing the wheels on one axle from spinning, a line lock seems difficult to implement with all-wheel drive. But Ford’s patent application, which was published by the United States Patent and Trademark Office (USPTO) on Sep. 26, 2023 (and originally filed on Nov. 23, 2020), suggests a way.
Instead of trying to spin all the wheels at once, Ford discusses using a controller to brake some wheels while others spin, alternating until each tire has been warmed up. This could be done by braking both wheels on one axle, or by braking individual wheels. So burnouts could be done with one axle and then the other, or by spinning the left or right wheel on a given axle while the opposite one is braked.
Ford all-wheel drive line lock patent image
In vehicles with mechanical all-wheel drive systems, the wheels on a given axle could also be disconnected from the drivetrain if they’re not being spun, Ford suggests. The patent application mentions vehicles with “a power plant, such as an engine” as well as vehicles powered by “an electric machine.” In the latter case, electricity would simply be routed to the wheels being spun and not the ones being braked.
Patented ideas don’t automatically go into production, but an all-wheel drive line lock could be a good fit for performance EVs. Ford already has the Mustang Mach-E GT in its lineup, with the Mach-E Rally on the way. Ford has also teased a high-performance F-150 Lightning concept, potentially in the vein of the original gas-powered F-150 Lightning.
https://www.motorauthority.com/news/1141016_ford-all-wheel-drive-line-lock-patent Ford’s working on an all-wheel-drive line lock