Year: 1886

page_text: the nature of this invention to be as follows:-
My invention relates to those engines in which the combustible charge of gas
and air is exploded under compression; the object being to give an uniform impulse
or expansion of the gases.
The cylinder is formed with cells or cavities for a considerable distance over
which the piston travels and the piston on the back stroke pushes the combustible
charge into these cavities and passes right on to the back end of cylinder. On
the out-stroke the first cell is fired by the ignition flame and each other cell is
fired in turn as the piston travels outward.
To keep the gases from passing out of the cavities on the backward motion of
the piston, the piston is made long enough to cover them with the usual number of
rings on each end. The rings next the crank work through a plain surface and do
not pass over any of the cavities while the back rings are made broad enough to
pass freely over them, and it will thus be seen that by this arrangement the gases
are pressed round the piston.
The valve used is a slidevalve for the admission of the charge and ignition flame
driven by a cam geared to the crank shaft.
By this cam the supply can be cut off at any part of the stroke, and this cam is
so made that by the assistance of a lever attached to the crank shaft in the form
of a ratchet the engine may be started without pulling the flywheel.
In engines of this kind where the combustible charge is above atmospheric
pressure there is a difficulty of ignition unless special provision is made in having
small holes or grooves formed in the face of the valve or cylinder for the purpose
of causing an equilibrium between the compressed charge and the lighting cavity
in the slidevalve. I prefer to dispense with these small holes or grooves and so
form the inlet port into the cylinder and lighting cavity in slide-valve so that the
ignition of compressed charge may be effected.
The governor used operates by the motion of the slide-valve and consists of two
weights on a bell crank, one weight is made to move at pleasure in a horizontal
position the other may be lifted and lowered over a running pully or drawn along
a flat surface.
:

page_text: I, GEORGE MCGHEE of 690 Springfield Road Glasgow in the County of Lanark,
Scotland, Engineer do hereby declare the nature of this invention and in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement :-
:
This Invention relates to those gas motor engines in which the combustible.
charge of gas and air is exploded under compression, and consists of improvements
for rendering the impulse or expansion of the gases more uniform; effecting the
ignition of said gases more easily; actuating the valve; and governing the engine.
more simply than heretofore.-Figures 1 and 2 on the accompanying drawings
illustrate respectively an elevation and plan of part of an engine embodying the
said improvements.
The cylinder A as shown in section clearly at Fig. 3 is formed with cells or
cavities 6 and is fitted with an extra long piston provided with one or more
packing rings d on each end thereof to keep the gases from passing out of the cells
on its back stroke. The rings next the crank, working over a plane surface do not
pass over any of the cella, while the back ring being made broad enough freely
passes over them. The piston on its back compressing stroke presses the
combustible charge into the cavities b. On the igniting outstroke the charge at
end of cylinder is first fired by the igniting flame, which said ignited charge then
fires the charge in next cell and each other cell in turn as the piston travels
outwards, thereby giving a more uniform impulse or expansion throughout the
stroke than if fired all at once.
There is difficulty of ignition in gas engines where the combustible charge is
above atmospheric pressure unless provision is made in having small holes or
grooves formed in the face of the valve or cylinder for the purpose of causing a
gradual equilibrium of pressure between the compressed charge and contents of
lighting cavity in slide valve. In lieu of these small holes or grooves I prefer as
indicated respectively at Figs. 1 and 4 to form the inlet port into the cylinder,
and lighting port or cavity f in slide valve diagonal or angular in reverse
directions, so that said ports shall open gradually at first thereby preventing the
igniting flame from being extinguished by sudden exposure to compressed charge
in cylinder. One side of the supply cavity f of the valve, is made angular as
shown dotted at Fig. 4 to correspond with port e in cylinder.
The valve rod g Figs. 1, 2 & 5, sliding through the guide g¹ is reciprocated by a
cam h fixed by screw pins or bolts (Fig. 5.which represents side of spur-wheel
with cam) to the side of the spur wheel driven at half the speed of the crank
shaft. The pitch line of spur-wheel is indicated respectively in Figs. 1 and 5 by
the plain and dotted large circles. The rod g is fitted by means of bolts and
nutsk with anti-friction rollers m, between and against which the cam h revolves,
thereby actuating the valve,

page_text: By varying the position and configuration of the acting surface of the cam, the
cut off of the supply or motion of the valve can be correspondingly varied, and it is
here explained that the position of cam relatively to the rollers as indicated by the
draughtsman in dotted lines at Fig. 1 is shown as if the engine were revolving
contrarily to the usual direction. The position of the cam when engine revolves in
usual direction is represented in plan at Figure 2.
8
The governor as represented at Fig. 1 comprises a bell-crank n the lower arm o of
which is screwed and pointed finely at outer end, and provided with weight of the
position of which can be varied from centre by turning on screw. The crank n is
fitted on its centre into the top of a bracket a fixed to and reciprocating with the
slide valve rod g. The crank n is fitted so as to cant through a small angle only,
so that the lower arm o shall not fall below the horizontal position, nor the top
arm n be knocked back out of the recess u. The lower arm o is shown is in its
lowest and normal position its point being on the same level as the notch on end
of gas controlling valve rod, so as to enter said notch r when travelling thereto,
thereby opening the gas valve. A guide rod s is fixed to the engine and a weight t
slides thereon. The weight t has a recess u somewhat longer than width of top
arm n which works inside and against the ends of said recess so as to allow said
arm n to travel a little at beginning of each stroke before meeting the weight t,
which at normal speed it comes gently against and draws along with it the rest of
stroke. Should the engine exceed its normal speed the top arm n strikes the
weight with more force and before having time to overocme its vis-inertiae is
canted back thereby lifting the lower arm o point, above level of notch, thereby not
opening the gas valve. The weight o¹ brings down the arm o to its horizontal
position again on back stroke. In lieu of the sliding weight t a weight w Fig. 6
attached by cord over pulley w³ to top arm n may be used. The weight w rests on
a support unless when the lower arm point o is about to enter the notch r when
the slack of the cord is taken up by the travel of the arm n and said weight w is
raised, the weight o¹ keeping the arm o in its normal position as shown unless
engine should exceed its normal speed, when the arm n moves faster than weight o¹
is adjusted for and said arm n gets a greater tug thereby lifting the point of arm o
above level of notch thereby not opening the gas supply valve. As shown at
Fig. 7 instead of a weight and cord w or t, an adjustable weight t' screwed on an
arm v of a bell-crank lever centred on a stationary part of engine may be used.
The two weights and o¹ being so adjusted from centres of levers that when the
arm n moves at its normal speed against the arm x, the point o retains position
shown, so as to open the gas valve, and said arm n pushes arm before it, thereby
lifting the weight t; but when engine exceeds normal speed and arm n moves
faster it strikes arm x with greater force and is canted back thereby lifting the
point of rod o past notch r and thereby not opening the gas valve.
If desired, the governor may be made to automatically stop opening the gas
supply valve and thereby stopping the engine when it goes below a certain speed.
In this case the bell-crank is so centred that the point of lower arm o may fall
below the level of notch r (the rise and fall it makes being indicated by dotted
lines) The relative proportion of the weights to one another, or their distances
from fulcrum, which in practice can be found easily by trial, are so adjusted that
at the desired speed of the engine the point of rod o shall enter the notch r and
open the gas supply valve; but if the engine goes too slow the arm n is arrested
very gently at first by the weights t, w or t, which weights yield therewith, thos
allowing the point of rod o to keep below level of notch r and consequently the
gas valve remains shut and engine stops.
Having now particularly described and ascertained the nature of my said
Invention, and in what manner the same is to be performed I declare that what
I claim is
1. The construction and use of motor cylinders having cells or cavities 6
substantially as and for the purpose described and shown.

page_text: 2. Making the valve cavity f, and cylinder port e angular or diagonal, as and for
the purpose set forth and indicated at Figs. 1 and 4.
3. The construction and combination of a cam h protruding from side of spur-
wheel, with rod g fitted with two rollers m as described & shown at Figs. 2 & 5.
4. The governor, constructed with two weights and cranked levers, arranged and
operating as set forth and shown at Figs. 1, 6 and 7.
Dated this 20th day of October 1888