Locating prior art for an EV regenerative braking algorithm by bypassing automotive databases and analyzing 1990s high-speed electric train schematics.
The target patent claimed a dynamic regenerative braking torque algorithm for use in modern electric vehicles (EVs).
The patent asserted novelty based on a specific feedback loop that dynamically adjusted the electrical braking force of the motor based on real-time wheel slip and battery state-of-charge, preventing the wheels from locking up while maximizing energy recovery.
Cut-off Date: Prior to 2005
Prior to 2005, fully electric passenger vehicles were not mainstream. Standard automotive searches primarily returned patents for internal combustion engine (ICE) ABS systems, which rely on hydraulic pressure, not electrical torque.
Previous search efforts were restricted to B60T (Vehicle brake control systems) specifically tailored for passenger cars. If the algorithm was used in a different class of vehicle, it would not appear in the results.
We stripped away the concept of "passenger cars." The core physics involved managing kinetic energy conversion to electrical energy in a massive moving object with wheels.
We asked: What other industry utilized massive electric motors and regenerative braking decades before modern EVs? Answer: High-speed electric railways.
We bypassed automotive databases entirely and tasked our researchers to dig into 1990s railway engineering manuals and locomotive control schematics.
Our researchers uncovered a 1994 technical schematic and accompanying engineering paper for a European high-speed electric locomotive.
The documentation detailed the exact regenerative braking torque algorithm. To prevent the massive steel wheels from slipping on the tracks during deceleration, the train's computer dynamically adjusted the electrical resistance of the motors using the exact same feedback loop claimed in the modern EV patent.