Early Brayton engine lithograph taken from Dugald Clerk's 1886 book "Oil and Gas Engines" - available without copyright on the internet. The image probably dates to 1873, but even if that is incorrect then Dugald Clerk died in 1932 hence categorised as :

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This engine is the original gas engine (not gasoline), and most later engines were liquid fuelled. It is unlike any working engines before, and unlike most piston engines since. The following account from Dugald Clerk summarises its action :

"In this engine there are two cylinders, compressing pump and motor. The charge of gas and air is drawn into the pump on the out-stroke and compressed on the return into a receiver ; the pressure usual in the receiver varies from 60 to 80 Ibs. per square inch above atmosphere. The motor cylinder takes its supply from the receiver but the mixture is ignited as it enters, a grating arrangement preventing the flame from passing back; the mixture, in fact, does not enter the motor cylinder at all ; what enters it, is a continuous flame. At a certain point the supply of flame is cut off and the piston, moving on to the end of its stroke, expands the volume, of hot gases to nearly atmospheric pressure before discharge."

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