IMPROVEMENTS IN GAS ENGINES
Year: 1884

page_text: PROVISIONAL SPECIFICATION.
I, GEORGE FREDERICK REDFERN, of the General Patent Office, No 4, Sonth
Street, Finsbury, in the county of Middlesex, Patent Agent do hereby declare
the nature of the said invention for " IMPROVEMENTS IN GAS ENGINES to be as
follows:-
There are three sources of waste of heat in Gas engines, viz A large part of it
is imparted to the cylinder and carried away in the water that surrounds it. The
quantity of gas that can be drawn into the heated cylinder per stroke is less than
it would be if that were cooler. And in engines compressing the gas in the
cylinder only alternate strokes can be made to impart power, other kinds requiring
more complicated mechanism.
The present improvements consist in drawing the gas into a cool cylinder, com-
pressing and transferring it to a hot chamber in which it can be fired and utilized
without losing heat by conduction; and also in drawing in the cool gas and expelling
that which is used at every stroke instead of at alternate ones.
The following is a description of the mechanism by means of which these results
are produced: The cylinder of the engine is prolonged about two diameters the
extended part being sufficiently widened to allow a non-conducting lining within it.
This part of the cylinder is to be used for a combustion chamber, and is preferable
to a separate vessel bolted upon the cylinder in regard to cost and tightness and
because it may be made so thin at its lower part as almost to prevent conduction
downwards.
In this space is placed an inner piston so moved by any suitable mechanism as
to fill the combustion chainber when the large piston is nearly at the end of its out
stroke; and then to be moved down upon that piston when it is nearly at the end
of its inner stroke, following close to it during most of its out stroke, being with-
drawn from the combustion chamber and filling the part of the cylinder which is
left by the piston as that moves outwards.
This inner piston has in it a valve opening towards the combustion chamber.
The admission valve is placed on the cylinder between the two pistons and the
exhaust on the combustion chamber,

page_text: The cycle of movements of the gas is as follows: Beginning when the inner
piston begins to move away from the larger piston gas flows in between them
through the admission valve, and at the same time the spent gas is driven out of the
exhaust from the combustion chamber into which the inner piston moves. Next
as the larger piston moves inwards and the inner piston moves down upon it
simultaneously the gas is compressed and transferred to the combustion chamber.
At this time the larger piston is at the end of its inner stroke, the inner piston is
nearly touching it, with the compressed gas all in the chamber. It is now fired,
expands, forces the pistons outward, completing the cycle.
By this method the gas is introduced into a cool cylinder; compressed and
transferred to a hot chamber where it is fired and expanded and thence exhausted
at every revolution.
When set vertically a water jacket is not required in engines of certain sizes, the
downward conduction proving slight in the larger ones.

page_text: DIECIFICATION
I GEORGE FREDERICK REDFERN of the General Patent Office N° 4 South Street,
Finsbury in the county of Middlesex, Patent Agent do hereby declare the nature
of the said 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:-
.
There are three sources of waste of heat in gas engines viz: A large part of it is
imparted to the cylinder and carried away in the water that surrounds it. The
quantity of gaseous mixture that can be drawn into the heated cylinder per stroke
is less that it would be if that were cooler. And in engines compressing the
mixture in the cylinder only alternate strokes can be made to impart power, other
kinds requiring more complicated mechanism.
The present improvements consist in drawing the mixture into a cool cylinder
compressing and transferring it to a hot chamber in which it can be fired and
utilized without losing heat by conduction and also in drawing in the cool mixture
and expelling the products of combustion at every stroke instead of alternate ones.
The following is a description of the mechanism by means of which these results
are produced The cylinder of the engine is prolonged about two diameters the
extended part being sufficiently widened to allow a non-conducting lining within
it. This part of the cylinder is to be used for a combustion chamber and is pre-
ferable to a separate vessel bolted upon the cylinder in regard to cost and tightness.
and because it may be made so thin at its lower part as almost to prevent con-
duction downwards.
In this cylinder is placed an inner piston so moved by any suitable merchanism
as to fill the combustion chamber when the outer piston is at about half stroke and
then to be moved down upon that piston when it is nearly at the end of its inner
stroke, following close to it during most of its out stroke, being withdrawn from
the combustion chamber and filling the part of the cylinder which is left by the
outer piston as that moves outwards,
This inner piston has in it a valve opening towards the combustion chamber.
The admission valve is placed on the cylinder between the two pistons and the
exhaust on the combustion chamber.
In order to enable the invention to be fully understood I will proceed to describe
the same by reference to the accompanying drawing in which figure 1 is a vertical
section of a gas engine constructed according to this invention, figure 2 is a section
of part of the cylinder drawn to a smaller scale shewing the arrangement which-
I sometimes employ for ensuring the ignition of the mixture in the combustion
chamber. Similar letters in both the figures represent similar parts.
a a¹ is the cylinder of the engine which is prolonged to the extent of about two-
diameters, and b, is the non-conducting lining within the extended part a¹ of the
cylinder, the diameter of which is enlarged as shewn to allow of placing the lining
therein; the said lining is of fire brick or fire clay or of plumbago or fire clay
faced with plumbago, and openings are left therein near the top as shewn for
exhaust and ignition; the part a' of the cylinder is to be used for (and is herein-
after referred to as the combustion chamber) instead of employing a separate vessel

page_text: bolted upon the cylinder whereby the cylinder may be made so thin at its lower
part such as at, a³ as almost to prevent any downward conduction of heat to the
lower part a of the cylinder which is used as the compressing chamber; c is the
inner piston placed in the space or combustion chamber a' and of a slightly less
diameter than the cylinder so as to fit loosely and move freely therein as I have
found that it is then tight enough to expel the burnt mixture from the combustion
chamber; this is important in utilizing the power to move the piston as its action
is very quick at certain parts of its stroke; this piston in small engines consists of
a cylinder of sheet iron filled with clay and in large engines as shewn in the
drawing, it consists of a drum formed with light cast iron heads with sheet iron
sides rivetted thereto; d'is the outer piston which works gas tight in the lower
part a of the cylinder and through which passes and works the rod e of the inner
piston c; f. is the valve in the inner piston opening into the passage flin the
piston c, leading to the combustion chamber a' the said valve serving to ensure the
discharge of the spent gas; any compression below the piston c is transferred to
the gas above it through the passage f¹and when the explosive mixture is fired as
the pressure is above the valve it is kept on its seat; the compression is caused
by the inward movement of the outer piston & whereby all the mixture in the
machine is compressed; g, is the pipe through which the explosive mixture is
admitted to the compressing chamber a and provided with a suitable valve the said
pipe being situated between the two pistons c and d; h is the pipe for the exhaust
and i the opening from the ignition valve; b¹ is a recess or clearance space in the
outer piston d, for the purpose of preventing the said piston from covering the
inlet g, at the upper part of the movement of the said piston. To the lower end of
the rod e of the inner piston c is jointed at j, a connecting rod or link k, the upper
end of which is jointed at l, to a bell crank lever m, pivotted at n to the standard
of the engine; the other end of the bell crank lever m is jointed at 2, to a link q,
connected with the crank r, on the shaft w of the engine; by this arrangement of
lever and links, motion is communicated to the fly wheels, by the descent of the
inner piston c each time the mixture is fired in the combustion chamber a¹; to the
crank T, is jointed a connecting rod t, which is jointed to and operates the outer.
piston d; the arrow indicates the direction of revolution of the fly wheel s.
0₁
The admission exhaust and ignition valves are all worked by excentrics or cams.
on the shaft w.
The cycle of movements of the Gas is as follows :—
Beginning when the inner piston c, and its connecting mechanism are in the
position indicated by dotted lines the outer piston d will be in the position shewn
in the drawing; the two pistons will begin to move away from each other, the
mixture will flow in between them through the admission valve on the pipe g, and
at the same time the products of combustion of the previous charge will be driven
out of the exhaust h, from the combustion chamber a', into which the inner
piston c, moves, as shewn by the full lines in the Drawing. Next, as the outer
piston d moves inwards and the inner piston c moves down upon it simultaneously,
the Gas is compressed and transferred through the Valve fand passage f¹, to the
combustion chamber a'.-At this time the outer piston d, is at the end of its inner
stroke, the inner piston o is nearly touching it with the compressed gas all in the
combustion chamber a².
It is now fired, expands and forces the pistons outward completing the cycle.
By the herein described method the Gas is introduced into a cool cylinder,
compressed and transferred to a hot chamber where it is fired and expanded and
thence exhausted at every revolution.
When set vertically as shewn in the Drawing a Water jacket is not required
in engines of certain sizes the downward conduction proving slight in the larger
ones.
In order to ensure the ignition of the explosive mixture in my improved gas
engine I provide a small pipe u, as shewn in figure 2, connecting the cylinder at a
suitable point in the compressing Chamber with the ignition Valve v, so that when

page_text: the inner piston c, is on its outward stroke a jet of the mixture will at the proper
moment be forced through the pipe u, across the flame in the ignition valve v,
whereby the said jet will be ignited and be drawn at the same time into the upper
part of the cylinder or space left by the inner piston. By this arrangement as the
inner piston has only partly performed its outward stroke when the ignition takes
place the said ignition is more gradual and is effected with less impact on the
piston.
I find it advantageous to employ a spiral or other suitable spring (not shewn in
the Drawing) which I attach to the lower end of the piston rod c, the said spring
being sufficiently strong to more than counterbalance the weight of the piston c.
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 described combustion chamber cast in one piece with the Cylinder so
as to form a portion thereof substantially as and for the purposes hereinbefore
described.
(2) The combination of the two pistons operating in the same Cylinder
substantially in the manner and for the purposes hereinbefore described and
represented in the accompanying drawing.
(3) In a gas engine the combination of an inner piston with a combustion
chamber cast with or attached to the cylinder substantially as hereinbefore
described.
(4) In a vertical Gas Engine the use of a Cylinder so constructed as to avoid
the necessity of the employment of a Waterjacket round any part thereof
substantially as hereinbefore described and represented in the accompanying
drawing.
(5) Connecting the compressing chamber with the ignition valve whereby the
ignition of the mixture is ensured in the combustion chamber substantially as
hereinbefore described and represented in the accompanying drawing.
(6) A. Gas engine in which the gaseous mixture is drawn into a cool cylinder in
which it is compressed and from which it is transferred to a hot chamber where it
is ignited and utilized without loss of heat by conduction the said mixture being
drawn in and the products of combustion expelled at every stroke of the Engine
substantially as herein beforo described.
(7) The improved Gas engine herein before described and represented in the
accompanying Drawing.
100F