Typical Gas Engines' and 'Vapour Engines'

Excerpted from Gas and Oil Engines


| April/May 1996



External View of Niel Engine

Fig. 339 External View of Niel Engine

The Niel Engine

Sent to us by Richard D. Hamp, 1772 Conrad Avenue, San Jose, California 95 I 24-4501

A novel type conical rotating valve is employed in the Niel engine for controlling the whole distribution of the charge and the exhaust. By means of suitable gearing the valve is made to rotate once for every two revolutions of the crank, and during this period it effects successively the admission of the mixture to the cylinder, the ignition, compression, and expansion and finally the exhaust of the burnt gases. An ingenious arrangement ensures sufficient gas tightness and prevents the valve from sticking. Although the four-stroke cycle is used, suction only takes place during two-thirds of the forward stroke, and the quantity of gas drawn in is therefore less than the volume of the cylinder. From this there results a certain economy, as the expansion is not so great and the compression is less. The incandescent tube arrangement introduced by Leo Funck in 1883 is adopted for the ignition.

The Martini, Sombart, Adam, Roger, and Kientzy Engines

Although built by different makers, these engines, which work on the Otto cycle, differ from one another in unimportant details only. Considering also the absence of any novel features it is unnecessary here to do more than mention their names.

Lablin Engine

Mr. Lablin of Nantes devised what may be considered as the gas type of the Brotherhood steam engine, that is to say, an engine combining the greatest possible power with the minimum weight and size. To quote Mr. Lablin's words, the engine was devised with a view to increasing the 'dynamical density' of the gas engine, and he so far succeeded in being able to construct engines of half a horse power weighing only 88 lb. and engines of 8 HP weighing less than 3 tons with a consumption of 35 cu. ft. of town gas or 1 lb. of gasoline. The engine works on the Otto cycle but three cylinders arranged radially around one crank are used, and the system of working is such that an explosion takes place in each cylinder successively, there being thus three driving strokes per revolution of the common crank. A flywheel of the minimum proportions may then be used, as the driving effort is practically uniform. When the crank occupies the position shown in Fig. 344, and when the direction of motion is that indicated by the arrow, explosion occurs in cylinder A, and its piston drives the crank. Exhaust of the waste gases commences from cylinder B, and the piston of C finishes the suction stroke preparatory to the compression of the mixture. Between the end of one driving period and the commencement of the next the interval does not exceed one-sixth of a revolution. Firing of the mixture may be effected either by the use of a heated ignition tube or by an electric spark, the former method being usually adopted when the working substance is gas, and the latter for oil vapours. The speed of the engine was controlled by a centrifugal governor which acted upon the gas-admission valve.

The National Engine

Gas engines are built by the National Company in all sizes from the smallest of 1 HP to the largest units burning producer gas. Petrol engines are built by the same company for effective powers of from 1 to 10 HP. All of these engines, whether gas or oil, are provided with two large well-balanced flywheels which ensure uniformity of the rotational motion; but this uniformity is also partly due to the use of a novel form of centrifugal governor which materially reduces the consumption. Fig. 349 illustrates the outward appearance of the gas engine, and also with minor differences that of the oil engines, which are provided in addition with a vaporizer and lamp placed at the front and with an oil reservoir immediately above the cylinder. Special attention has been devoted to the reduction of the number of the parts, and the result has been a design of the simplest possible description. One cylinder alone is used for all engines of less than 50 HP. The starting gear has been much simplified, and the ignition arrangements are such that miss-fires rarely occur. Much skilled attention is not required to keep the engine in good condition and the lubrication is for the greater part done automatically.

Forest Engine

Reference has already been made to the two-cycle non-compression engine first introduced by Mr. Forest, who has made the gas engine the subject of considerable research work. Two other interesting types of Forest engine, working on the four-stroke cycle, have also been introduced with considerable success. In one of these types, which is of a specially compact design, the cylinders