The main automotive application with the lock-up principle was Packard's Ultramatic transmission, launched in 1949, which locked up the converter at cruising speeds, unlocking once the throttle was floored for rapid acceleration or since the vehicle slowed. Torque converter equations of motion are governed by Leonhard Euler's eighteenth century turbomachine https://deanklifc.loginblogin.com/41314833/torque-converter-clutch-an-overview