IMPROVEMENTS IN GAS ENGINES
Year: 1882

page_text: PROVISIONAL SPECIFICATION left by the said John McGillivray at the
Office of the Commissioners of Patents on the 10th August 1882.
**
JOHN MCGILLIVRAY, of Glasgow, in the County of Lanark, North Britain,
'IMPROVEMENTS IN GAS ENGINES,"
This Invention, which relates to improvements in gas engines, has especial
reference to the construction and arrangement of the valves, and mechanism
actuating the valves, for the admission of the gas and air, and for causing the
ignition and explosion of the combustible charge, and effecting the exhaust of the
waste vapour.
The improvements are applied to single acting engines in which the piston is
directly connected to the crank, and the outer end of the cylinder is open to the
atmosphere, the combustible charge of hydro-carbon gas and air being admitted to
the inner close end of the cylinder at or near the ordinary atmospheric pressure to
act by their explosion at each revolution of the crank shaft.
In a modification of the improved engine in which the cylinder is fitted
horizontally on a bed plate or framing, also carrying the crank shaft journal
bearings, the valves which regulate the admission of gas and air, and that by which
ignition of the explosive mixture is controlled, are all arranged horizontally and
transversely or across the cylinder and are operated against the power of springs,
by means of cams or wipers on a rotating shaft fitted parallel to the longitudinal
centre line of the cylinder, and driven by gearing from the crank shaft.
The valve through which the gas is admitted to the cylinder is by preference
made in the form of a sliding tube or piston valve which when pressed back by the
action of its actuating cam or wiper opens a small hole or port to admit the gas
from a service pipe through the tubular valve casing to an inlet tube which leads
into the rear end of the cylinder, preferably on the upper side. The atmospheric
air which is admitted to form the explosive mixture is led into the cylinder by an

page_text: inlet tube close to the gas tube, fitted with a piston valve similar to that by which
the gas is admitted but of much larger area, the two valves, and the duration of
their opening being so regulated that the requisite proportions of air and gas shall
be allowed to enter the cylinder.
Strong springs are fitted in connection with the valves for the gas and air, and
are made to keep the valves closed excepting when they are pressed back by the
cams or wipers on the rotating cam shaft, and to close them quickly when the
cams or wipers release the valves. The cans or wipers are made with a quick
curve to press back the valves, and with short segmental parts which retain the
valves in the open position for the requisite time, or part of the stroke of the piston,
to admit the charge of combustible gas and air to the cylinder. The gas and air
valves are both opened at once, and for about the same length of time, during the
first part of the outstroke of the piston and both are suddenly closed by the action
of the springs when the cams pass, and while the piston has only traversed about
one third of its outward stroke.
Simultaneously with, or immediately following the closing of the gas and air
admission valves, a third cam or wiper on the same cam shaft acting against the
power of a spring, presses back a small slide or valve and allows the flame of a
constantly burning gas jet to be momentarily drawn or to play through an opening
in the rear end of the cylinder and ignite the combustible charge within, thereby
causing the explosion of the charge which drives forward the piston.
The exhaust passes out as usual on the return stroke by means of a port and
opening through a slider or sliding valve on the end of the cylinder operated by a
crank or eccentric on the cam shaft, but which is so actuated as only to open the
exhaust port after about one half of the instroke of the piston is inade and allow
the partial vacuum which follows the explosion, to act on the rear of the piston
during the early part of the instroke.
These operations are repeated at each revolution of the crank shaft, a charge of
gas and air being admitted for every outstroke of the piston. A fly-wheel is fitted
on the crank shaft but may be made lighter than usual; and a water jacket is
provided to surround. and cool the cylinder in the ordinary way, or the cylinder
may be cooled by simple radiation.
And when desired, two or more of these cylinders may be connected to cranks at
right or other angles on the same shaft, or with the cylinders at different angles to
the same crank and crank shaft, and so dispense with the necessity of the use of a
fly wheel, which is necessary for single cylinder engines of this construction.
The engine may be made double acting by closing the outer end, and duplicating
the valves which control the admission of gas and air, and which admit the
igniting flame and effect the exhaust. In either case the admission of the gas and
air may be controlled by a single valve or by separate valves operated by the same
cam or wiper. A suitable governor of ordinary construction may be provided to
control or partially control the admission of gas and air or to cut off the inlet of
gas and air at any stroke when the speed and power developed may be greater than
is desired.
When the engine is applied to drive tramway cars or for locomotive purposes
generally, the supply of gas may be carried in suitable vessels under pressure in
which case the gas may be admitted to the cylinder at a higher pressure than that
of the atmosphere

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said John McGillivray in the Great Seal Patent Office on the
9th February 1883.
JOHN M GILLIVRAY, of Glasgow, in the County of Lanark, North-Britain
"IMPROVEMENTS IN GAS-ENGINES
"
My said Invention, which relates to improvements in gas engines, has especial
reference to the construction and arrangement of the valves, and mechanism
actuating the valves, for the admission of the gas and air, and for causing the
ignition and explosion of the combustible charge, and effecting the exhaust of the
waste vapour.
My Invention is illustrated by the accompanying Drawings in which Figure 1 is
a sectional elevation, Figure 2 is a plan, and Figure 3 is an end elevation of the
improved gas engine. Figure 4 is a horizontal section of the engine cylinder.
Figure 5 is a cross section at the end of the cylinder, showing the air and gas inlet
ports, and exhaust port, as also the ignition valve; And Figure 6 is a cross section
of the slide regulating the exhaust. Figure 7 is a vertical section of the cylinder
of my improved gas engine with a slightly modified arrangement of the exhaust
valve; And Figure 8 is a cross section of the saine at the end of the cylinder.
The improvements are shown applied to single acting engines in which the
piston A is directly connected to the crank B and the outer end of the cylinder C
is open to the atmosphere, the combustible charge of hydro-carbon gas and air being
admitted to the inner close end of the cylinder at or near the ordinary atmospheric
pressure to act by an explosion at each revolution of the crank shaft.
In this modification of the improved engine in which the cylinder C is fitted
horizontally on a bed plate or framing D, also carrying the crank shaft journal
bearings E, the valve F, which regulates the admission of gas and air is arranged
horizontally and transversely, or across the cylinder, and is operated against the
power of a spring G by means of a cam or wiper H on a rotating shaft I, fitted
parallel to the longitudinal centre line of the cylinder C, and driven by bevil
gearing J, J, from the crank shaft B.
The valve F through which the gas and air are admitted to the cylinder, is by
preference made in the form of a sliding piston with notches g and a cut in it, so
that when pressed back by the action of its actuating cam or wiper H, the
notches g come opposite a small hole or port g', to admit the gas from a service
pipe K through the notch g in the valve casing to an inlet port g which leads into
the rear end of the cylinder C, while the atmospheric air which is admitted to form
the explosive mixture, is led into the cylinder C by a port a¹ through the notch a in
the valve F, and through an inlet port a close to the gas port g. The air inlets
are of much larger area than those for the gas. The duration of opening is so
regulated that the requisite proportions of air and gas shall be allowed to enter the
cylinder. A strong spring G is fitted in connection with the valve F, for the gas
and air, and is made to keep the valve closed excepting when pressed back by the
cam or wiper H on the rotating cam shaft I, and to close them quickly when the
cams or wipers release the valves. The cam or wiper H is made as is shown
particularly in figures 2 and 3 with a quick curve to press back the valves, and
with a short segmental part which retain the valve F in the open position for the
requisite tine, or part of the stroke of the piston A, to admit the charge of
combustible gas and air to the cylinder C. The gas and air inlets are opened
together, and for about the same length of time, during the first part of the
outstroke of the piston A, and both are suddenly closed by the action of the

page_text: spring G when the cam passes, and while the piston has only traversed about one
third of its outward stroke, so that the pressure on the piston resulting from the
explosion is applied when the crank is in the most effective position. A cam or
wiper I' on the cam shaft I, acting also against the power of a spring M, oscillates
a bell-crank lever N, the lower arm of which engages with and depresses a small
small slide or ignition valve O. The opening of this valve O allows the flame of
a constantly burning gas jet P to be drawn in, or to play through a port or opening
¿ in the rear end of the cylinder C, and ignite the combustible charge within. A
slide which regulates the exhaust, has a small opening in it, which in its travel
only comes opposite the jet opening i, at the time when the explosion should occur;
and the flame is only allowed to play through the ignition port i momentarily,
before the valve O is pressed up and closes the ignition port i. The exhaust passes
out on the return stroke by means of a port e, and a notch or opening e' formed in
the slide or sliding valve Q fitted at the end of the cylinder. The slide Q is operated
by a crank R on the cam shaft I and connecting rod S jointed to the end of the
slide, and the slide is so actuated as only to open the exhaust port e after about one
half of the instroke of the piston is made; and so allows the partial vacuum which
follows the explosion to act on the rear of the piston during the early part of the
instroke. These operations are repeated at each revolution of the crank shaft, a
charge of gas and air being admitted for every outstroke of the piston. A
fly-wheel T is fitted on the crank shaft B, but may be inade lighter than usual;
and a water jacket or air space, or other refrigerating medium is provided to
surround and cool the cylinder in the ordinary way, or the cylinder may be cooled
by simple radiation.
The modification of gas engine shown in figures 7 and 8, only differs from that
described in having a small piston valve U fitted in substitution of the slide Q,
and in having the valve operated by a bell-crank V from au eccentric on the
crank shaft, instead of from the wiper shaft.
Two or more cylinders (C) may be connected to cranks at right angles on the
same shaft, or the cylinders placed diagonally and connected to the same crank
shaft, to dispense with the use of a fly-wheel.
The engine may be made double acting by closing the outer end and duplicating
the valves which control the admission of gas and air, and which admit the
igniting flame and effect the exhaust. In either case, the admission of gas and
air may be controlled by a single valve as described, or by separate valves operated
by the same cam or wiper. A suitable governor of ordinary construction may be
provided to control or partially control the admission of gas and air or to cut off
the inlet of gas and air at any stroke when the speed and power developed may
be greater than is desired.
When the engine is applied to drive tramway cars, or for locomotive purposes
generally, the supply of gas may be carried in suitable vessels under pressure, in
which case the gas may be admitted to the cylinder at a higher pressure than that
of the atmosphere.
Having thus described my said Invention, and the manner of performing the
Bame, I have to state that I do not restrict myself to the precise details herein
described or delineated, but what I consider to be novel and original, and
therefore claim as the Invention secured to me by the hereinbefore in part recited
Letters Patent is,―
First. The arrangement and combination of parts of a gas engine substantially
as herein described and illustrated by the accompanying Drawings.
Second. In a gas engine, the construction and arrangement of a Gas and air
admission valve or valves operated by means of a cam or wiper and spring,
substantially as herein described and illustrated by the accompanying Drawings.
Third. In a gas engine, the construction and arrangement of an ignition valve
operated by a cam and spring to act in unison with the valve admitting the
combustible charge, substantially as herein described and illustrated by the
accompanying Drawings.

page_text: Fourth. The combination in a gas engine, substantially as herein described and
illustrated, of a valve admitting the combustible charge to the cylinder, and an
ignition valve operating in unison therewith.
In Witness Whereof, I the said John M Gillivray, have hereunto set my
hand and seal, this Eighth day of February in the year of our Lord One
thousand eight hundred and eighty-three.
Witness,
WRM THOMSON,
Patent Agent,
Glasgow.
JOHN MCGILLIVRAY (L.S.)