Practical Hand Book of Gas, Oil and Steam Engines / Stationary, Marine, Traction; Gas Burners, Oil Burners, Etc.; Farm, Traction, Automobile, Locomotive; A simple, practical and comprehensive book on the construction, operation and repair of all kinds of engines. Dealing with the various parts in detail and the various types of engines and also the use of different kinds of fuel.

by John B. Rathbun

(46) Stationary Four Cylinder Engine.

An English stationary engine, the Browett-Lindly, similar in many respects to the automobile engines just described, is shown in longitudinal and cross-section by Figs. 20 and 21. This is of the “L” type of valve arrangement, but instead of having the valves side by side as in the preceding case, the inlet valve is placed over the exhaust as will be seen from the cross-section view.

Fig. 21. Cross-Section Through Browett-Lindly Engine.

The exhaust valve is operated directly from the cam shaft by the push rod as in the auto engines, but the inlet valve receives its motion through a long vertical rod and horizontal lever, the latter being located on the cylinder head as shown by the longitudinal section. A supplementary valve is mounted loosely on the stem of the inlet valve, and this valve is held against the seat of the gas inlet port by a short spring.

Fig. 20. Section Through Browett-Lindly Four Cylinder Stationary Engine.

A collar on the main valve spindle opens this gas valve, and, by adjusting the position, a certain amount of lag can be given, so that air first enters the cylinder and then, by further travel of the main valve, the gas valve opens and the combined charge is taken in. This prevents any “back fires” as the gas and air are entirely separated until they enter the cylinder.

Starting is effected by means of compressed air, and is entirely automatic. No compression release is provided, as this is unnecessary under the system adopted. By opening the main compressed air valve compressed air is admitted to two valve boxes placed underneath the cam shaft, and the pressure of air raises the valves against their levers and cams. Should the swell on the cam be opposite a lever as it will be in the correct starting position, the valve cannot close, and the compressed air then passes to the cylinder through a check valve on the face of the cylinder, and the engine starts. The automatic check allows the cylinders to take in a charge of mixture on the second stroke and firing takes place immediately. When the explosion pressure is greater than the air pressure the check remains closed and no more starting air enters the cylinder.

Fig. 21-a. Section Through Cylinder of Fairbanks-Morse Type “R E” Engine, with Valves in the Head.

Governing is effected by varying both the quantity and quality of the mixture.

The main valve, plunger, and rod springs, and all springs on the valves and valve motion, are arranged to be in compression. The exhaust valves are of cast-iron, and are fitted with renewable seats in the cylinders. The admission valves are of nickel steel, and are arranged in boxes, which, when removed from the cylinders, provide the ports which give access to and space for the removal of the exhaust valves which are withdrawn vertically.

Forced lubrication is fitted throughout all bearings, valves, plunger guides, governor, cam shaft, etc., the oil under pressure being supplied by two valveless pumps, either of which is sufficient to maintain the working pressure of oil.

The normal output of the engine is 400 brake horse-power, with an allowable overload of 40 horse-power for ½ hour. The exhaust pipe is water jacketed, each section being supplied from the small pump shown at the end of the cross section.

Double ignition is provided for an emergency, by two high tension magnetos, each of which is connected to a separate set of plugs. When starting the engine, an ordinary spark coil and storage battery are used until the engine gets up to speed, when the coil is cut out and the magneto is thrown in.