Lenoir Engine
In 1860, Jean Joseph Étienne Lenoir, a Frenchman, produced the first practical gas engine—a one horse-power machine of the double acting type, equipped with a cylinder 75 mm in diameter, in which a piston worked with a 165 mm stroke. In this engine, the charge composed of an explosive mixture of gas and air, was drawn into the cylinder during the first half of the forward stroke of the piston and exploded by an electric spark from a Ruhmkorff coil at the beginning of the second half of the stroke. The burnt gas was expelled during the return stroke at the same time that effective work was being done by the explosion on the other side of the piston. The igniter was placed in the cylinder wall at a point opposite the half length of the stroke, so that the platinum igniter points protruded into the cylinder. The electric spark that jumped continually between them was exposed to the gas in each end of the cylinder, alternately, by the forward and backward movements of the piston. The cylinder was provided with a water jacket for preventing the overheating of its walls, and the engine worked so smoothly and regularly that it inspired the belief that it would prove a successful substitute for the steam engine.
So much so, that several prominent firms began manufacturing them in sizes up to 12 horse-power; but many defects were soon discovered, especially the enormous expense for fuel due to the consumption of over 2.83 cubic meter of illuminating gas per brake horse-power under the most favorable load, and their manufacture was soon discontinued. Fig. 1, shows a general view, and Fig. 2, a cross-section of the cylinder.