PETROL MOTORS AND MOTOR CARS. PETROL MOTORS. INTRODUCTORY. I. The Beau de Rochas, or Otto Cycle.-It was in 1862 that M. Beau de Rochas, a French engineer, patented an internal combustion engine, the principles of which have formed the basis for designers of this class of engine ever since. The conditions laid down in the patent, upon which the success of the engine depended, were (a) Maximum cylinder capacity, with a minimum of circumferential surface. (b) High piston speed. (c) Greatest possible compression. (d) Maximum pressure at the commencement of the power stroke. With the exception of b, these conditions have been embodied in all the most successful internal combustion engines. The exception, high piston speed, has also been adopted to a certain extent. It has been found that the piston speed is limited in practice. The Beau de Rochas cycle is often miscalled the Otto cycle, chiefly because Dr. N. A. Otto was the first to make practical use of it in an engine, but the whole credit of the invention is certainly due to Beau de Rochas. B 2 |