Charles Yale Knight

Charles Yale Knight (born 1868 in Indiana), was originally an American printer and newspaper publisher, publishing a Midwest farm journal called Dairy Produce. To cover dairy activities during 1901–02, he bought an early Knox automobile, a three-wheeler with an air-cooled, single-cylinder engine whose noisy valves annoyed him. He believed that he could design a better engine and proceeded to do so. Knight was familiar with the slide valves used on early Otto engines, having repaired the similar valve mechanism in his father's sawmill. The slide valve had, however, been replaced in gasoline engines by the poppet valve, whose characteristics were better suited to four-stroke engines.

At first Knight tried making the entire engine cylinder reciprocate to open and close the exhaust and inlet ports. Though he patented this arrangement, he soon abandoned it in favour of a double sliding sleeve principle. Backed by Chicago entrepreneur L.B. Kilbourne, an experimental engine was built in Oak Park, Illinois in 1903. Research and development continued until 1905, when a prototype passed stringent tests in Elyria, Ohio. Having developed a practicable engine (at a cost of around $150,000), Knight and Kilbourne showed a complete "Silent Knight" touring car at the 1906 Chicago Auto Show. Fitted with a 4-cylinder, 40 hp (30 kW) engine, the car was priced at $3,500.