Internal Fire Museum of Power - Willans central valve engine

Image: © Chris Allen Taken: 14 Oct 2018

This single cylinder engine is No. 3146 of 3.5 indicated horsepower is believed to have been an exhibit at the 1900 Paris Exhibition along with a much larger example. It is single acting with steam acting above the single piston. Steam distribution is by a piston valve inside the hollow piston rod and actuated by an eccentric integral with the crank pin. Below the working cylinder is an air buffer cylinder that ensures the force on the crank pin is always down and also acts as a piston guide. Lubrication was by splash. Forced lubrication was developed by a competitor in 1891 and remains the norm for modern internal combustion engines. The engine has a centrifugal spring loaded governor operating a throttle valve. This engine used to be owned by Alstom and was preserved at the Willans Works in Rugby but is now on display at Internal Fire with a larger three crank engine, also from Rugby. See Image

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