Fig. 11.—Niel Gas Engine (elevation and sectional plan).
Lombart, Martini (Fig. 12), Adam, Le Parisien, and Le Kientzy motors.—All these motors, each of which is constructed by a different maker, are based in principle on the Otto engine, and except for slight modifications of the working parts, they do not call for any particular notice. The small amount of space at our disposal only admits of our mentioning them.
Fig. 12.—Martini Motor.
Lablin motor (Fig. 13).—M. Lablin of Nantes set himself to produce a motor which should correspond with the Brotherood and Westinghouse steam engine, that is to say, a motor developing the maximum of power for the minimum of space and weight. This might be termed the dynamic density of the motor, which M. Lablin sought to increase. He has succeeded in constructing gas motors of ½ horse-power weighing about 90 lbs., and of 8 horse-power weighing 7 cwt. Unfortunately they consume a rather large quantity of fuel—about 1000 litres of coal gas, or 500 grammes of gasoline per horse-power hour. There are three cylinders grouped at equal distances round the same shaft, and all attached to one single crank. By this arrangement a more constant torque or twisting movement on the shaft is obtained, and consequently the weight of the fly-wheel can be considerably reduced. Three explosions are produced during every revolution, that is to say, each cylinder performs a complete cycle of operations during every revolution, a fact which accounts for the low efficiency. Ignition is obtained by a platinum tube heated to incandescence when using coal gas, and by an electric spark when carburetted air is used. The governor is centrifugal, and controls the admission of gas.
Fig. 13.—Lablin Three-cylinder Motor.
Crossley Bros. gas engine (Figs. 14, 15).—This engine is from the cycle point of view purely and simply an Otto gas engine. A light shaft runs parallel to the cylinder, being driven by a worm-gear of the crank-shaft. On it are situated the cams which force open the four spring-valves, controlling respectively the admission of air gas and the ignition and exhaust.
Fig. 14.—Crossley Gas Engine (X type).