IMPROVEMENTS IN GAS MOTOR ENGINES
Year: 1880

page_text: PROVISIONAL SPECIFICATION left by Christopher Thomas Wordsworth at
the Office of the Commissioners of Patents on the 28th May 1880.
CHRISTOPHER THOMAS WORDSWORTH, of Leeds, in the County of York.
"IMPROVEMENTS IN GAS MOTOR ENGINES."
The first part of my Invention relates to improvements in that class of gas engine
in which two pistons are employed, one connected to the crank shaft and the other
being loose, both working in a vertical cylinder, and between which pistons the
gaseous mixture is exploded. The improvements consist in an effective arrangement
of mechanism for gripping or holding the loose piston after it has been thrown
upwards from the working piston. I attach an angular grooved rod to the top
side of the loose piston, and which piston rod is guided through the end or cover of
the cylinder, and as a means of gripping or holding this piston I apply a metallic
wedge to the purpose, the face of which is formed to correspond with the grooves in
the piston rod; this wedge, owing to the peculiar form of the grooves and the way
it is guided up and down, is capable of locking itself between the said rod and
the tapered back of the box or recess in which such wedge is mounted, and in
order to facilitate the requisite and instantaneous disconnection or withdrawal of
such wedge from the rod I arrange that the said wedge shall be guided up and
down in suitable grooves, set at the required angle, and to be released by means of
a suitable lever arm actuated by a cam or other suitable mechanism.
This grooved rod and clutch arrangement may be also applied to other
constructions of gas engines, say, to single pistoned gas engines employing a
movable cross head, in which case the wedge would be applied to locking the
grooved piston rod in the cross head.
I also employ a pneumatic system of clutch for the same purpose consisting of an
additional cylinder mounted upon the top of the working cylinder and closed at its
upper end; a rod from the loose piston passes through a gland into this additional
cylinder (which may be a simple extension of the working cylinder) and is secured
to a piston (hereinafter called the pneumatic piston), valves being applied at the
top and bottom of this cylinder. The action of this pneumatic clutch is as
follows:-As the pneumatic piston is forced upwards in its cylinder by the
explosion of the gases in the cylinder below it draws in after it a body of air
through the open valves and ejects the air on its upper side, but as soon as the

page_text: loose piston to which it is attached is arrested by the collapsing of the gases in the
lower cylinder the valve close, and to prevent the fall of the loose piston until the
pressures equalise themselves, when the pneumatic piston is released by other
mechanically operated valves which are opened at the desired point in the revolution
of the crank shaft.
My improvements in this class of gas engines further consist in employing a
rotary valve, which can either rotate entirely or partially;. this valve being provided
with suitable chambers or ports for receiving a supply of explosive mixture and
firing the same in the cylinder, such firing taking place by preference at the
opening in the said valve which is nearest to the explosion port.
This improved valve works in a cylindrical body or casing, which may be split
in two halves to facilitate the adjustment of the two working faces, back and front,
or the same arrangement of valve may be constructed to reciprocate, in which case
it would be formed as a slide valve.
I further employ a back pressure valve, either alone or in combination with a
gas mixer, the back pressure valve being designed to shut off all communication
with the gas supply when the engine stops through overloading or other causes,
and thus I avoid all danger of explosions. This back pressure valve consist by
preference of a mushroom or pendant valve mounted on a suitable seating and held
thereto by a light sensitive spring or springs, or the weight of such valve being so
adjusted as just to resist the maximum gas pressure.
The gas mixer, which may be attached to or form part of the aforesaid back pressure
valve, consists of a hollow perforated stem, surrounding which are a series of
longitudinal, radial, or spiral ribs of alternate varying lengths, and which when
placed in a suitable casing form tortuous passages or channels for the air and gas
mixture to travel along, the air entering at one end of the apparatus and meeting
with the gas which enters through the perforations in the hollow central stem, so
that by the time the air and gas is ready to escape at the other or outlet end of the
apparatus such air and gas has become thoroughly incorporated and forms a more
homogeneous explosive mixture.
Secondly. My improvements relate to high pressure or explosive gas engines.
In constructing this class of engine I have a diagonal framing with a crank shaft
mounted in bearings between two inclined cylinders, the pistons of which are
connected to one and the same crank or crank shaft. One cylinder is the working
or expansion cylinder and the other is the air charge and compressing cylinder; the
former is made of a larger diameter than the latter by reason of the piston being
made by preference hollow throughout, or of the through trunk type, in order to
allow a perfect circulation of cool air through the centre of the piston during the
working. The inside of this trunk piston is arranged with a number of gills or
projections similar to the gills used in heating stoves, and is so designed to enlarge
the cooling surface; this piston at its upper or tail end passes through a gland
fitted with metallic or other suitable packing. The working cylinder has first
clearance at the end, and is connected by a pipe to a separate combustion chamber
suitably disposed between the air compressing and working cylinders, whilst such
air compressing cylinder is also connected to the same combustion chamber through
the ports of the explosion valve, which may be of the rotary form hereinbefore
described or of the slide valve form.
The action of this engine may be described as follows:- -When the engine is
turned by hand or other means and the air compressing piston moves downwards,
in doing so it draws in first a charge of explosive mixture (gas and air) for a
portion of the stroke, then in continuation of the same stroke it draws in a body of
air up to the end of the stroke. During this downward motion of the said piston
the exhaust or eduction valve remains open between the combustion chamber and
the working cylinder, and still remains open during the descent of the working
piston, and during a portion of its ascent and up to near the firing point. This
enables me first to allow the residuum of the exploded gases, which may occupy or
lodge in any part of the working cylinder or combustion chamber, to escape, and

page_text: then through the same eduction valve to draw in fresh air, and thus to completely
flush the cylinder and combustion chamber with such fresh and pure air.
The relative position of the two cylinders causes the air compressing piston to
be a little in advance of the working piston. When the air compressing piston
reaches the bottom of its stroke, in returning upwards it forces the air and its
charge through a port in the firing valve into the combustion chamber, and just at
this time a double beat piston valve mounted in the said combustion chamber is
timed by suitable mechanism to close the communication with the working cylinder,
so that when the air compressing piston completes its outward stroke it has
compressed the body of air taken in last by forcing it first into the combustion
chamber, and the charge of gas and air taken in first is left to the last and is
compressed, say, to about two atmospheres, with this advantage that as the
combustible charge is closer to the ports the firing is rendered more certain. About
this time the eduction valve is closed, the working piston having arrived near to
the end of its upward stroke, a continuation of which stroke serves to compress
the contents of the working cylinder to or nearly to the same pressure as the
contents of the combustion chamber, at which instant the firing is timed to take
place. The double valve is now relieved and the charge ignited, causing the
working piston to fly downwards.
During this time round the air compressor draws in nothing but air, and on its
return outwards such air is compressed slightly through the valves not opening into
the combustion chamber until the expansion of gases have carried the working
piston close to the full throw of the crank; the exhaust valve then opens, and at
the same time the valve port opens the communication between the combustion
chamber and the air compressing cylinder, whereby the slightly compressed air
flows into the combustion chamber and flushes, cools, and ejects the products of
combustion lodged therein, the same escaping through the eduction valve along with
that which is left in the working cylinder up to the end of the stroke of the
working piston. The action hereinbefore described is then repeated, the eduction
valve being open; the working piston draws in cool air in its downward stroke to
be ejected in its up stroke, and so on, every alternate revolution.
It will thus be observed that the firing takes place at every alternate revolution
of the crank, but in some cases, by otherwise timing the valves, I fire at every
revolution.