Year: 1886

page_text: I, JOHN MAGEE of 56 Great Hamilton Street, in the City of Glasgow, Engineer;
do hereby declare the nature of this invention to be as follows:-
My invention relates to gas motor engines of the class wherein a charge of
combustible mixture is drawn into the cylinder, compressed therein and thereafter
exploded to develope mechanical power and it consists of improvements in the
construction, organisation and mode of operating certain parts whereby extreme
simplicity and a high degree of efficiency are secured.
In carrying out my invention I employ a cylinder, or two or more cylinders, with
a reciprocating piston or pistons connected to the crank shaft in the usual way and
I supply the gas or mixture of gas and air forming the explosive charge through a
lift valve at or near the end of the cylinder, which valve is opened by the suction
created during the outstroke of the piston and is so connected to a cut off valve in the
gas supply passage that when the piston attains a higher speed than is desired and.
the lift valve is in consequence raised above the normal point the cut off valve
arrangement is brought into action to partially stop the gas supply and by.
lessening the supply of combustible mixture to reduce the speed or power of the
engine.
The firing of the charge instead of being effected as is usual by a burning jet
whose flame is communicated to the charge within the cylinder through an ignition
port or orifice cut in the cylinder is accomplished by means of a hot tube which is
maintained at the temperature of incandescence by means of a bunsen burner.
playing upon it externally, or by similar means. The interior of the hot tube
whose outer end is closed is in communication with. a cavity at the end of the
cylinder covered by a flap valve or lift valve which is opened by a tappet on the
piston at the moment when the piston reaches the end of its instroke in the act of
compressing the combustible charge within the cylinder, and which thereby admits:
to the ignition cavity and to the interior of the hot tube a portion of the,
compressed charge. This portion of the charge on coming in contact with the red
hot tube is fired and in exploding lifts the valve on the ignition cavity and passing
therethrough fires the charge within the cylinder thereby forcing the piston
outwards.
The exhaust or discharge of the products of combustion is effected through an
automatically operated valve which is kept closed during the explosion and
expansion of the gases within the cylinder but which is opened when the piston
reaches the end of its out-stroke. The valve which may be conical or in the form
of a disc is fitted in the side of the cylinder and within the compression space
between the end of the cylinder and the piston at the termination of its in-stroke.
The valve opens inwards and is provided with a spindle projecting outside the
cylinder and acted on by a beain lever whose opposite end is connected to or
'

page_text: operated on by a piston or diaphragm fitted in a cylindrical chamber communi-
cating by a port with the interior of the engine cylinder. This port is situated at
a point which is uncovered and opened to the interior of the cylinder only at the
termination of the out-stroke of the piston, and when by the explosion of the
charge the piston is forced out a portion of the highly expanded gas passes by
the port into the cylindrical chamber at the side and forces outwards the piston
or diaphragm therein, thereby acting on the lever whose opposite end presses on the
exhaust valve spindle and thereby opens that valve for the discharge of the spent
gases. Before the exhaust has fairly commenced the side port is closed by the
working piston passing over it on its return stroke and there being no outlet for
the gases confined within the cylindrical chamber the pressure maintained therein
serves by acting through the piston and lever to keep the exhaust valve open, but
on the working piston reaching the end of its instroke the side port is uncovered
by the piston and is thus opened to the atmosphere and the pressure being relieved
the exhaust valve is no longer kept open.
In some cases I fit in the compression space at the end of the cylinder a loose
piston which is arranged to clear out and take the place of the "residuum
"
"
which
in ordinary gas engines is left in the compression space of the cylinder at the end
of each cycle of operations. A stop is provided to prevent this loose piston from
passing into the cylinder beyond the point at which it meets the working piston at
the end of its instroke. The space between the loose piston and the fixed cylinder
end or cover communicates by a pipe or passage with the interior of the main
cylinder at a point which is only uncovered at or near the end of the outstroke of
the working piston, and this space is filled with the gases or products within the
engine at that point of the stroke. When the piston returns on its in-stroke to
discharge the spent gases or exhaust it comes close up to the loose piston, and
there being no free space no
residuum can be left in the cylinder. The piston on
its out-stroke draws in the combustible charge, and on its in-stroke compresses it
and as it reaches the end of the instroke the loose piston is pressed towards the
cylinder end until an equilibrium of pressure is established between the compressed
combustible charge on one side and the fluid between the loose piston and the
cylinder end on the other. When the explosion takes place the compressed fluid
in the space between the loose piston and the cylinder end serves as an elastic
cushion for that piston which is thereby prevented from striking the cylinder
end;
and on the commencement of the exhausting operation the loose piston is
pressed inwards by the fluid to meet the working piston and clear out the spent
charge from the cylinder.
For governing the speed or power of the engine I joint or pivot to any recipro-
cating part such as the piston rod or the slide valve when such is used, a rod or
bar which is balanced by a suitably adjusted weight connected to it through a cord
or chain or links and levers. This balanced rod or bar strikes against a valve
spindle and opens a spring valve in the gas supply passage, at each stroke provided
a uniform speed is maintained, but on the speed increasing the inertia of the weight
is not overcome with sufficient rapidity and the balanced rod or bar is dragged out
of the line of the valve spindle and the valve being unacted on the supply of gas
is checked during that stroke and the speed of the engine is reduced to the normal
point.
The various features of improvement above described may be applied in combi-
nation in a gas engine, or they may be separately applied in gas engines in other
respects of ordinary construction.

page_text: Improvements in Gas-motor Engines.
I, JOHN MAGEE of 13 Dixon Street, Glasgow, in the County of Lanark, Engineer,
do hereby declare the nature of this invention for IMPROVEMENTS IN GAS ENGINES
and in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement reference being had to the annexed
2 sheets of Drawings illustrating my said improvements:-
On sheet 1 of the Drawings, Figure 1 is a longitudinal section, Figure 2 a
transverse sectional elevation, and Figure 3 a plan of an Engine constructed with
my improved back or loose piston, and means of working same. The engine may
be otherwise constructed and worked as described in the Specifications No. 9544 of
28th June 1884, and No. 11422 of 25th September 1885 of previous patents
granted to me. The cylinder is fitted at the back with the loose piston a as shown
at Figure 1, with a rod 6 passing through a stuffing box so as to make an airtight,
or nearly so chamber or space c whose capacity is variable, according to the position
of piston a. To the end of the rod b is fitted as shown a cap d which prevents the
piston a being sucked or driven too far into the cylinder when in action. A pipe
or passage e shown in dotted lines at Figs. 1 and 3 Sheet 1 makes a communication
between both ends of the cylinder & is fitted with an ordinary ball or trap
non-return valve i opening only towards the chamber c so as to allow the fluid
from between the two pistons to flow to the chamber c but not back again there-
from. Assuming as shown at Figure 1, that the motor piston is about half way
out on the explosion outstroke the piston a has been driven partly back, com-
pressing the fluid in the chamber c until the pressure in the cylinder falls below
that in said chamber c, when the piston a now advances forward corresponding
with the lessening pressure in cylinder, until the motor piston has almost reached
the end of its outstroke and uncovered the inlet of pipe e, when the pressure
remaining between the pistons will pass to the chamber c until the pressure on
both sides of a corresponds. The exhaust valve h¹ being now lifted allows the
products of combustion between the pistons to escape on the return instroke of
motor piston, thereby lessening the pressure on front of the loose piston a which is
then driven full stroke in by the fluid behind it preponderating in pressure. There
being no outlet from behind piston a it remains full in nearest motor piston, the
said motor piston nearly meeting it when full in also, and so wholly or nearly so
expelling the products of combustion. The loose piston a remains full in towards
the motor piston during the charging outstroke of said motor piston; but during
the compressing instroke of the motor piston the loose piston a is pressed a little
backwards leaving a space between the two pistons after the motor piston is full in,
in which space the combustible or explosive charge is retained until ignited. The
fluid in chamber c by allowing the piston a to be driven back & thus being
compressed, acts as a cushion, lessens the shock of explosion and stores up energy
which is given out again by its expansion forcing forward the piston a, as the
pressure decreases between the two pistons after the explosion on the outward
stroke of the motor piston.
On sheet 2 of the drawings Figures 1 and 2 are respectively a longitudinal and
transverse section through the cylinder of an engine, showing a mode in accordance
with this Invention of working the exhaust valve h¹ by a small piston k through
the lever j. The piston k is fitted into a small cylinder on bottom of main.cylinder
with which it communicates by the port m when the main piston is full out as

page_text: shown at Fig. 1, the pressure remaining after the explosion at the end of the
explosion stroke driving down the small piston k thereby actuating upwards the
exhaust valve h¹ and allowing the cylinder to exhaust. When the front of
the main piston has passed over the port m on return stroke; the valve end
of the lever j and valve h¹ being heavier than the piston kend and piston k, the
top of piston k being open to the atmosphere rises and closes the valve h¹. In lieu
of weight, a spring may be used to shut the said exhaust valve.. On the charging
outstroke and compressing instroke of main piston, the exhaust valve remains
closed there being no preponderating pressure on top of small piston k to actuate it.
A mode of igniting the explosive or combustible charge of gas and air by means
of a red hot pipe in accordance with this invention, is shown at figure 4 Sheet 2
of the drawings, and comprises an outer-end closed metallic pipe p (which is heated
by a bunsen burner or other ordinary means not shown) fitted airtight to the
cylinder by means of an intermediate piece as shown having a trap valve n opening
only to the inside of cylinder. A passage leads between the inside of the tube p
and cylinder and is provided with a valve o on the stem o¹, said valve being kept
shut by a spring.o unless when the main piston is full in and pressing it open.
The ignition takes place at the end of the compression instroke of the motor piston
by its pressing the valve o open and allowing part of the explosive charge to enter
and come in contact with the inside of the hot pipe, when it ignites and forces
open the valve n & ignites the charge in cylinder. Another mode of igniting the
mixture in combination with an adjustable back piston 20, which may be used in
lieu of above is shown fully at Fig. 6 Sheet 1 & consist of an open pipe p which is
heated only to a given point from entrance, so that the charge inside cylinder must
attain a certain pressure (which can be regulated by the adjustable piston 20 at
back of cylinder) before part of said combustible charge reaches the igniting or red
hot part of pipe p.
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 arrangement and combination of loose piston a, rod b, cap d, pipe or
passage e, and valve i substantially as and for the purpose described and shown
at Fig. 1, Sheet 1 of drawings.
2. Utilising the variable space c in combination with the piston a and back
cover of cylinder, as and for the purpose described and shown at Figs. 1 Sheets 1
and 2 of drawings.
3. The use of the pipe or passage e with or without the valve i, as and for the
purpose set forth and shown at Figs. 1 and 2 Sheet 1 of drawings.
4. The combination of piston k, passage m, lever; and valve h¹ as and for the
purpose described and shown at Fig. 1 sheet 2, of drawings.
5. Working the exhaust valve through the piston k, by means of the pressure
inside cylinder substantially as described and shown at Fig. 1 Sheet 2 of drawings.
6. The arrangement and construction of parts for igniting the charge as described
and shown at Fig. 4, Sheet 2 of drawings.
7. The mode of igniting the charge in an open partly hot pipe, in combination
with an adjustable piston 20, as described and shown at Fig. 6, Sheet 1 of drawings.
8. In a gas engine the use, singly or in combination, of any one or more of the
Improvements, as herein before described and claimed.
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