The accompanying engravings illustrate a new and very simple form of gas
engine, the invention of J. A. Ewins and H. Newman, and made by Mr. T.
B. Barker, of Scholefield-street, Bloomsbury, Birmingham. It is known as
the "Universal" engine, and is at present constructed in sizes varying
from one-eighth horse-power--one man power--to one horse-power, though
larger sizes are being made. The essentially new feature of the engine
is, says the _Engineer_, the simple rotary ignition valve consisting of
a ratchet plate or flat disk with a number of small radial slots which
successively pass a small slot in the end of the cylinder, and through
which the flame is drawn to ignite the charge. In our illustrations Fig.
1 is a side elevation; Fig. 2 an end view of same; Fig. 3 a plan; Fig. 4
is a sectional view of the chamber in which the gas and air are mixed,
with the valves appertaining thereto; Fig. 5 is a detail view of the
ratchet plate, with pawl and levers and valve gear shaft; Fig. 6 is
a sectional view of a pump employed in some cases to circulate water
through the jacket; Fig. 7 is a sectional view of arrangement for
lighting, and ratchet plate, j, with central spindle and igniting
apertures, and the spiral spring, k, and fly nut, showing the attachment
to the end of the working cylinder, f1; b5, b5, bevel wheels driving
the valve gear shaft; e, the valve gear driving shaft; e2, eccentric to
drive pump; e³, eccentric or cam to drive exhaust valve; e4, crank to
drive ratchet plate; e5, connecting rod to ratchet pawl; f, cylinder
jacket; f1, internal or working cylinder; f2, back cylinder cover; g,
igniting chamber; h, mixing chamber; h1, flap valve; h2, gas inlet
valve, the motion of which is regulated by a governor; h3, gas inlet
valve seat; h4, cover, also forming stop for gas inlet valve; h5, gas
inlet pipe; h6, an inlet valve; h8, cover, also forming stop for air
inlet valve; h9, inlet pipe for air with grating; i, exhaust chamber;
i2, exhaust valve spindle; i7, exhaust pipe; j6, lighting aperture
through cylinder end; l, igniting gas jet; m, regulating and stop valve
for gas.
[Illustration: IMPROVED GAS ENGINE]
The engine, it will be seen, is single-acting, and no compression of the
explosive charge is employed. An explosive mixture of combustible gas
and air is drawn through the valves, h2 and h6, and exploded behind
the piston once in a revolution; but by a duplication of the valve and
igniting apparatus, placed also at the front end of the cylinder, the
engine may be constructed double-acting. At the proper time, when the
piston has proceeded far enough to draw in through the mixing chamber,
h, into the igniting chamber, g, the requisite amount of gas and air,
the ratchet plate, j, is pushed into such a position by the pawl, j3,
that the flame from the igniting jet, l, passes through one of the slots
or holes, j1, and explodes the charge when opposite j6, which is the
only aperture in the end of the working cylinder (see Fig. 7 and Fig.
2), thus driving the piston on to the end of its forward stroke. The
exhaust valve, Fig. 9, though not exactly of the form shown, is kept
open during the whole of this return stroke by means of the eccentric,
e3, on the shaft working the ratchet, and thus allowing the products of
combustion to escape through the exhaust pipe, i7, in the direction of
the arrow. Between the ratchet disk and the igniting flame a small plate
not shown is affixed to the pipe, its edge being just above the burner
top. The flame is thus not blown out by the inrushing air when the slots
in ratchet plate and valve face are opposite. This ratchet plate or
ignition valve, the most important in any engine, has so very small a
range of motion per revolution of the engine that it cannot get out of
order, and it appears to require no lubrication or attention whatever.
The engines are working very successfully, and their simplicity enables
them to be made at low cost. They cost for gas from ½d. to 1½d. per hour
for the sizes mentioned.
[Illustration: Fig.9.]
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