Clessie Lyle Cummins

A self-taught mechanic with no formal engineering degree, Clessie Cummins worked as a chauffeur and mechanic for the Irwin family of Columbus, Indiana, before persuading William G. Irwin to finance a diesel engine company in 1919.

Clessie Lyle Cummins (1888-1968) believed the diesel engine, then used mainly in ships and stationary plants, could be made light and fast enough to power vehicles. With William G. Irwin's backing he founded the Cummins Engine Company in Columbus, Indiana, in 1919. Early engines were built under license and sold for farm and marine use, and the company lost money for years. Clessie promoted diesel through endurance stunts: in 1931 a Cummins-powered truck crossed the United States on about $11 of fuel, and the Cummins Diesel Special completed the Indianapolis 500 without a pit stop. The company became profitable in 1937 as trucking fleets adopted diesel. Clessie held dozens of patents, including work on fuel injection and the compression engine brake later commercialized by Jacobs Vehicle Systems, a business Cummins itself acquired in 2022. (Exact birth year remains publicly undisclosed).