Dugald Clerk

Dugald Clerk was a Scottish engineer who developed the two-stroke internal combustion engine cycle, patenting his design in 1881 after several years of experimentation. His engine achieved a power stroke on every revolution of the crankshaft rather than every second revolution as in the four-stroke Otto cycle, and the two-stroke principle he established became, alongside Nikolaus Otto's four-stroke design, one of the two fundamental combustion cycles internal combustion engines have been built on ever since.