We present on this and the next page engravings showing the construction of a new gas engine, which in its method of governing, and in other details of construction, will be found to contain points of interest. As will be seen by the engravings, the frame of the engine is of a modified A form, with the crank-shaft at the top, and there are two cylinders of equal size, which are inclined, the one at the left being the working cylinder, while the one at the right is a pump in which the mixture of gas and air is first received and compressed by the pump piston, after which it passes through a large pipe connecting the two cylinders, and is admitted to the working cylinder by a poppet valve, the opening of which is controlled by the governor.
Gas
is admitted to the compressing cylinder by a pipe which enters the head,
and air enters through a number of holes which are made in the head around
the pipe, as shown by the end view of this head at the right of Fig. 1.
The holes through which air enters are covered by a valve which is opened
by atmospheric and seated by the pressure within the cylinder. The proportions
of gas and air are controllable by a valve in the gas supply pipe.
Near the working cylinder, and in the large pipe which joins the two cylinders, is a poppet valve having a stem projecting through a stuffing-box below, as shown at Fig. 3 (page 2). This valve is seated by the spiral spring shown, and is lifted to admit the explosive mixture to the cylinder by the lever shown below, which is pivoted to the side of the frame, and receives its motion from an eccentric which located just inside the fly wheel, as shown in section at Fig. 2, and side view in Fig. 4. This eccentric is in two parts joined together by a hinge joint at one side, one of the parts being secured to the end of the hub of the fly wheel by screws as shown, while the other is free to move upon the hinge joint to give greater or less eccentricity, its tendency to fly outwards being resisted by the spiral spring shown.
The amount of eccentricity is then controlled by the wedge seen at the left of the eccentric in Fig. 4, and under it, in Fig. 2, this wedge being attached to one of the arms of the fly wheel, and its distance from the center of the shaft controlled by the opposing forces of the spiral spring shown behind it, on the one hand, which tends to force it inwards and open the eccentric, while upon the other is the centrifugal force of the weight under the spring, which tends to withdraw the wedge and allow the eccentric to close. A half strap fits in the groove of the eccentric below, from which, by the connections shown in Fig. 3, the valve is moved, and admits more or less of the mixture to the cylinder, according to the requirements for the work being done, an explosion taking place at every revolution where needed, and yet leaving a margin for governing.
There is no exhaust valve, but towards the upper end of the cylinder there is a narrow opening or port, which passes entirely around the inside of the cylinder, and connects with the large passage seen, which also extends around the cylinder, and at the top is connected with the exhaust pipe as shown. The piston passes over this port at the end of the stroke, and exhaust takes place. The port, though of large area to give a free exhaust, is considerably narrower than the packing rings, so that there is no trouble from the rings entering and catching in it. The lighter is seen at the left of the working cylinder, Fig. 1, and is operated by a cam placed on the crank-shaft just inside the belt pulley.
A small jet of gas is kept burning, and a cylindrical valve operates to give communication with the contents of the cylinder at the beginning of the stroke.
Provision is made for cooling the cylinder by circulation of water, as shown, and also for through lubrication.
It has been found by experiment that the regulation is all that could be desired, and there is no trouble in stating the engine at any time.
The engines have been built in sizes from 1/2 to 3 horse-power, and are to be built up to 25 horse, by the Backus Water Motor Co., Newark, N.J.
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