Improvements in Gas Engines
Year: 1887

page_text: Date of Application, 28th Nov., 1887
Complete Specification Left, 25th Aug., 1888
Complete Specification Accepted, 23th Sept., 1888
I THOMAS STURGEON of Easby Drive Ilkley in the county of York Engineer do
hereby declare the nature of this invention to be as follows:-
In the specification of a Patent granted to me for Improvements in Gas Engines
dated 23rd July 1885 No. 8897 I describe a gas engine having two pistons working
in a cylinder which I call the working-cylinder and in which the charge of mixed gas
and air is ignited under compression between these pistons, this charge being supplied
by means of another piston working in a cylinder at right angles to the working-
cylinder and which I call the charging-cylinder.
I find however that in small engines where the total amount of gas used is so small
that it is not so necessary to study economy in this respect, and where it is more
essential to keep down the first cost, one of the pistons in the working cylinder may
be dispensed with together with the beam and crank and other parts appertaining
to it.
My present invention therefore consists in constructing a gas engine as follows-I
use a working cylinder and a charging cylinder placed at right angles to each other.
There is one piston in the working cylinder and one in the charging cylinder and
these pistons are connected to the saine crank on the crank shaft, one being connected
direct by means of a connecting rod and the other through the intervention of a
connecting rod sway-beam and link. The action of the pistons will thus be such that
one is moving through the middle or quickest part of its stroke while the other is at
about the end or slowest part of its stroke. Thus while the charging piston is at the
quickest part of its inward stroke rapidly driving a new charge of gas and air into
the working cylinder the working piston will be about the end of its outward stroke
where it exposes the exhaust ports and allows the old products of combustion from
a former charge to be expelled as they are displaced by the entrance of the new
charge. In this engine one end of the working cylinder is closed and I arrange
the ports so that the new charge will be delivered as close as possible to the closed
end so that the new charge as it enters may sweep the products of combustion of the

page_text: former charge before it. This I accomplish by making the port of a peculiar form.
Thus if the charging cylinder be horizontal and the working cylinder vertical it will
be most convenient for the ports in the slide valve and the valve face to be vertical
but as the port leading into the working cylinder approaches the interior I give it a
twisted form and not merely twisted but also askew so that as it opens into the
working cylinder it does so in a horizontal position close up to the cylinder
cover.
Instead of placing the cylinders at right angles to each other and using a straight
beam I might place the cylinders in a line or parallel and use a beam of the form
of a right angle or L shaped lever the object being to have one piston passing
through the middle or quickest part of its stroke while the other is about the end
or slowest part of its stroke.
In this engine the charge is of course ignited under compression being compressed
by the inward stroke of the working piston and ignited when it has reached the
point of maximum compression.

page_text: Improvements in Gas Engines.
I, THOMAS STURGEON of Easby Drive Ilkley in the county of York 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:-
In the specification of a Patent granted to me for Improvements in Gas Engines
dated 23rd July 1885-No. 8879 I describe a gas engine having two pistons working
in a cylinder which I call the working cylinder and in which the charge of mixed gas
and air is ignited under compression between these pistons this charge being supplied
by means of another piston working in a cylinder at right angles to the working
cylinder, and which I call the charging cylinder.
I find however that in small engines where the total amount of gas used is so small
that it is not so necessary to study economy in this respect and where it is more
essential to keep down the first cost, one of the pistons in the working cylinder may
be dispensed with together with the beam and crank and other parts appertainin
to it.
My present invention therefore consists in constructing a gas engine as follows-
I use a working cylinder and a charging cylinder placed at right angles to each
other.
There is one piston in the working cylinder and one in the charging cylinder and
these pistons are connected to the same crank on the crank shaft, one being connected
direct by means of a connecting rod and the other through the intervention of a
connecting rod, sway beam and link.
The action of the pistons will thus be such that one is moving through the middle
or quickest part of its stroke while the other is at about the end or slowest part of its
stroke. Thus while the charging piston is at the quickest part of its inward stroke
rapidly driving a new charge of gas and air into the working cylinder, the working
piston will be about the end of its outward stroke where it exposes the exhaust ports
and allows the old products of combustion from a former charge to be expelled as they
are displaced by the entrance of the new charge. In this engine one end of the
working cylinder is closed and I arrange the ports so that the new charge will be
delivered in as close as possible to the closed end so that the new charge as it enters
may sweep the products of combustion of the former charge before it. This I accom-
plish by making the port of a peculiar form. Thus if the charging cylinder be
horizontal and the working cylinder vertical it will be most convenient for the ports
in the slide valve and in the face it works against, to be vertical but as the port
leading into the working cylinder approaches the interior I give it a twisted form and
not merely twisted but also askew so that as it opens into the working cylinder it does
so in a horizontal position close up to the cylinder cover. Fig. 1 of the accompanying
drawings shews a general vertical section of an engine constructed according to my
invention. Fig. 2 being a horizontal section on an enlarged scale taken through the

page_text: cylinders and valve and Fig. 3 a partial transverse section through the working
cylinder. In all these Figs. the same letters refer to the same parts. A is the
charging cylinder the piston of which is here shewn at about the quickest part of its
inward stroke. It is now rapidly driving the new charge of gas and air through the
passages B. C and D into the working cylinder E, the old products of combustion
being simultaneously expelled through the exhaust ports F F into the exhaust box G,
the exhaust ports being at this time exposed owing to the piston in the working
cylinder having run past them. The charge is then compressed by the inward motion
of the working piston. In the mean time the slide valve is shifted so that the charging
piston may draw in a fresh charge into the charging cylinder the air being drawn in
through the port H in the valve and H' in the cover and the gas through the small
holes I.
The shifting of the slide valve, which is driven by means of an ordinary eccentric
also opens a communication between the upper part of the working cylinder and the
red hot igniting tube L so as to fire the charge when it reaches the maximum amount
of compression. The gas valve M and the igniting tube are carried by the slide valve
cover which is held up to its place by springs and clamps on screwed studs in the
usual way. The engine runs in the direction indicated by the arrow. The twisted
and skew port D is shewn in horizontal section in Fig. 2 and in vertical section in
Fig. 3.
The exhaust may be carried away through a pipe fixed to any convenient part of
the box G and may be run into another box before being allowed to escape to the
atmosphere, in order to reduce the noise.
Fig. 4 shews a plan view of the sway beam which is made in this form so that the
connecting rod brasses may lie beside those of the connecting rod of the charging
piston on the crank. The working cylinder is water jacketed in the usual way. When
the slide valve is in the position shewn in the drawing the igniting tube is open to
the atmosphere so that any products of combustion contained therein may fall to
atmospheric pressure and so leave it in a better state for firing the next charge. This
tube is beated by a Bunsen burner in the ordinary manner. By a simple rearrange-
ment of the various parts and ports, an engine may be made with the working cylinder
horizontal and the charging cylinder vertical.
This will be understood by a reference to Fig. 5 which is a sectional plan of the
cylinders and slide valve of an engine so arranged, the same letters as in the preceding
Figs. being used to denote the same parts but an engine so constructed would run in
the opposite direction to that just described. In this arrangement the twisted port
opens into the charging cylinder and forms the most convenient arrangement for con-
veying the charge to the vertical port in the valve face. Instead of placing the
cylinders at right angles to each other and using a straight beam I might place the
cylinders parallel and use a beam of the form of a right angle or shaped lever
the object being to have one piston passing through the middle or quickest part of its
stroke while the other is about the end or slowest part of its stroke. An engine so
constructed is illustrated in Figs. 6. 7 & 8. Fig. 6 being a section through the working
cylinder and bed and Fig. 7 a partial section through the charging cylinder and
shewing the right angled lever with its connecting rod coupled to the crank and
Fig. 8 a horizontal section through the two cylinders and slide valve. The cylinders
are here placed side by side and the slide valve works across their ends in jaws formed
on their covers, the motion being conveyed to it from the eccentric rod through the
bell crank lever N. Fig. 8. The valve is here shewn about the middle of its stroke.
It will be convenient to have two sets of studs springs and clamps to hold the valve
up to its face.
The right angled lever is shewn at O. O' Figs. 6 & 7. Suitable openings are left in
the bed so that this lever and its connecting rod may work through them as shewn
in Fig. 7. The twisted and skew port is not required in this form of engine.
In all other respects the engine is the same as those described and the same
letters being used to denote similar parts the description already given will apply
equally well in this case. This engine would run in the direction shewn by the

page_text: arrow. In all these arrangements the charge is of course ignited under compression
being compressed by the inward stroke of the working piston and ignited when it
has reached the point of maximum compression.
Having now particularly described and ascertained the nature of my said Inven-
tion and in what manner the same is to be performed I declare that what 1
claim is:
A gas engine with a charging cylinder and a working cylinder and one piston
in each cylinder these pistons being connected to one and the same crank, one direct
by a connecting rod and the other by means of a connecting rod, beain or lever
and link and so arranged that the piston of one cylinder shall be passing through
the middle or quickest part of its stroke while the other is at about the end or
slowest part of its stroke in the manner and for the purpose described.
Dated this 24th day of August 1888.
THOMAS STURGEON.