The Knight Engine (USA) was an internal combustion engine, designed by Charles Yale Knight (1868-1940), that used sleeve valves instead of the more common poppet valve construction.
Developed in 1903, Knight Engines provided greater power through the elimination of poppet valves - this also made the Knight engine more quiet than standard engines. The engines also allowed for Hemi-spherical chambers. Knight received backing from L. B. Kilbourne with whom he established Knight and Kilbourne in Chicago which licensed the engine to various companies and receive a royalty payment on each vehicle produced using the engine.
The engine was used by several United States automakers, many of which included "Knight" in their brand names to denote the relationship to the engine. However the expense of manufacturing the engine limited its application to high end model cars. In addition owners reported that the engines lacked power and were slow to accelerate.
From 1905 to 1907, Knight manufactured the Silent-Knight automobile both as showcase for the technology and as an attempt to enter the U.S. automobile market (who wouldn't bear the high premium at first.)
1907 Charles Knight settled in Coventry to work for Daimler
The Knight engine was developed to fruition in England gaining an earlier start in Europe, where it also lasted longer. Mercedes built their 4-litre Knight 16/50 until 1924, while the Simson Supra Knight of 1925-26 was probably the last German Knight-engined car. In France, besides Peugeot and Mors, two brands of luxury automobiles used the Knight engine as standard equipment between 1923 and 1940: Avions Voisin and Panhard et Levassor. Voisin also built an air-cooled radial engine using the Knight principle in 1935 which was their last use of Knight technology. The Panhard et Levassor Dynamic, produced until the summer of 1940, was the last Knight-engined passenger car to be built in series.
John North Willys of Willys-Overland was a strong promoter of the Knight Engine as was Frank Ballou Stearns of the F. B. Stearns Co. Willys produced the greatest number of Knight powered vehicles and in 1925 purchased Stearn’s company which brought Stearns-Knight under Willys-Overland control.
Moline-Knight (and its successor R & V Knight ) were the only licensee that cast its cylinders in block.
In August 1911, the engine was licensed by the US automobile makers Columbia, Stearns, and Stoddard-Dayton. A licence was also purchased by the Atlas Engineering Company of Indianapolis to make engines, which appeared in 1914 as the Lyons-Knight.
Columbia, Stoddard-Dayton, and Atlas went bankrupt shortly after and their licences were transferred to other companies. Edwards-Knight obtained one which they passed on to Willys, while Moline acquired another which they retained into the 1920s.
In 1913 a Mercedes-Knight driven by Théodore Pilette was entered in the Indianapolis 500 where, despite having the smallest engine, it took fifth place averaging 68.148 mph (109.674 km/h) over the 500 miles (800 km).
Willys made improvements to the Knight engine which were patented and in 1916 announced their Willys-Knight 88-4. They went on to open a Canadian manufacturing plant at Toronto to build export models.
By 1925 there were five operations in the US producing chassis with Knight engines so that Willys-Knight production was running at 250 cars per day. Willys announcing in the same year that there were over 180,000 Willys-Knight engines in use worldwide. Willys also took over Stearns that year, forming a separate syndicate for the purpose (the companies were not merged).
Sales of Willys-Knight cars declined towards the end of the 1920s. Thanks to the work of Harry Ricardo and Charles F. Kettering, simpler poppet valve engines had become very efficient, their first appearance being in the 1924 Chrysler, and the Knight engine's high manufacturing cost began to tell against it. While Willys built Knight models into the 1930s, development work had ceased. The Knight patents expired in 1932. Although a 1933 Willys-Knight Streamline Six was announced in June of that year, it is doubtful if production was continued into 1933. These were the last sleeve-valve automobiles manufactured in the US.
Sources of Information
-  Wikipedia