Sensaud de Lavaud
The Sensaud de Lavaud was a French automobile manufactured between 1926 and 1928. An unusual car, made in Paris by M. Dimitri Sensaud de Lavaud, a Brazilian, it had an automatic transmission. The Alpax chassis was cast alloy, and it was powered by a steam-cooled 5475 cc six-cylinder engine of American origin. Few were built.
The automatic transmission did not select between several gears - instead, it relied solely on the converter's torque multiplication.
André Citroën had intended to use a gearbox based on Sensaud de Lavaud's principles in his 1934-launched Citroën Traction Avant 7A, but it proved impossible for his engineers to make the car's 1300cc engine - coupled with Sensaud de Lavaud's invention - accelerate the vehicle and maintain acceptable speeds uphill, so the 7A appeared with a conventional 3-speed unit.
