IMPROVE- MENTS IN GAS MOTOR ENGINES
Year: 1883

page_text: LETTERS PATENT to George Gordon Picking and William Hopkins both of
Bow in the County of Middlesex Engineers for an Invention of IMPROVE-
MENTS IN GAS MOTOR ENGINES
"
PROVISIONAL SPECIFICATION left by the said George Gordon Picking
and William Hopkins at the Office of the Commissioners of Patents on the
16th November 1883.
GEORGE GORDON PICKING and WILLIAM HOPKINS both of Bow in the County
of Middlesex Engineers "IMPROVEMENTS IN GAS MOTOR ENGINES
»
These improvements relate to that class of gas motor engines which compress
the gas and air before ignition.
In engines as at present constructed the pressure in the cylinder resulting from
the explosion of the firing mixture is allowed to escape by the exhaust at a
considerable pressure above the atmosphere. To obtain greater economy of gas,
engines may be constructed so that the pressure of the gases in the cylinder
resulting from the explosion are utilized by acting against the piston and the
pressure of the exhausting gases reduced, to obtain this economy of gas the charge
of firing mixture left in the firing chamber and cylinder before compression is less
than the whole contents of the cylinder and chambers, this may be accomplished
by allowing the piston after it has completed its stroke to return a certain portion
of its stroke before commencing to compress the mixture either by keeping the
exhaust open or in engines which draw the firing mixture into the cylinder direct
by closing the air or air and gas inlet to the cylinder or both and forming a partial
vacuum in the cylinder while the cylinder is completing its stroke and so when the
mixture is compressed and fired utilize the further expansion of the gases in the
cylinder, Also great economy of gas may be effected by working the valve
which governs the inlet of gas to the engine by mechanism from the piston of the
engine or in engines which are supplied with firing mixture from a pump by
mechanism from the pump piston or rod. One means of carrying these improve-
ments into effect is shown in a gas engine constructed as follows A cylinder is

page_text: fitted with two pistons, one of these pistons is connected by a piston rod to a
crosshead and by a connecting rod to a crank, the other piston is moved in the
cylinder by eccentrics or cranks from the shaft of engine, the piston rod of this
second piston is hollow and works on the piston rod of the first described or main
piston the space between the pistons is used at pleasure to draw in and discharge
into the firing chamber or port and cylinder air to cleanse the same and drive out
the result of combustion, the space between the second piston and the cover of the
cylinder is used to draw in firing mixture and discharge same into the firing port
and cylinder after the same have been cleansed by the air. The air remaining in
the cylinder previous to the introduction of the firing mixture is driven out by
similar means to those described in our former Patent A.D 1883 May 18th 2492-
also the exhaust escapes at or near the end of the stroke of the first or main piston
The exhaust or discharge port may be governed by a valve worked from the shaft
placed in such a position in the cylinder that the piston is allowed to return a
portion of its stroke before compressing the contents of the cylinder and chamber
and so utilize the further expansion of the gas The firing chamber or port is
brought round from one end of the cylinder so that the mixture from the cylinder
at one end is conveniently discharged into the firing chamber or port, and the
slide for igniting worked direct from the shaft.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said George Gordon Picking and William Hopkins in the Patent Office on
the 16th May 1884.
GEORGE. GORDON PICKING and WILLIAM HOPKINS both of Bow in the County
of Middlesex Engineers "IMPROVEMENTS IN GAS MOTOR ENGINES"
These improvements relate to that class of gas motor engines which compress the
gas and air before ignition. In engines as at present constructed the pressure in
the cylinder resulting from the combustion of the firing mixture is allowed to
escape by the exhaust opening at a considerable pressure above the atmosphere.
To obtain greater economy of gas, engines may be constructed so that the pressure
of the gases in the cylinder resulting from the combustion of the firing mixture
are still further utilized by acting against the piston, and the pressure of the result
of combustion when the exhaust is opened reduced. To obtain this increase of power
and consequent economy of gas used, the charge of firing mixture left in the firing
chamber and cylinder before compression is less than the whole contents of the
cylinder and chamber, this may be accomplished by allowing the piston after it has
completed its stroke to return a certain portion of its stroke before commencing to
compress the mixture either by keeping the escape port open or (in engines which
draw the firing mixture into the cylinder direct) by closing the air or air and gas
inlet to the cylinder or both, and thereby forming a partial vacuum in the cylinder
while the piston is completing its outstroke, and so upon the return of the piston.
the mixture is not compressed until the piston has travelled some portion of its
return stroke, when the mixture is compressed and fired, upon the next outstroke
the further expansion of the gases resulting is utilized, Also great economy of
gas may be effected by working the valve which governs the inlet of gas to the
engine by mechanism from the piston of the engine or in engines which are supplied
with firing mixture from a pump by mechanism from the pump piston or rod. One
means of carrying these improvements into effect is shewn in a gas engine
constructed as follows. A cylinder is fitted with two pistons one of these pistons
is connected by a piston rod to a crosshead and by a connecting rod to a crank the
other piston is moved in the cylinder by eccentrics or cranks from the shaft of the
engine, the piston rod of the second piston is hollow and works on the piston rod
of the first described or main piston, the space between the pistons is used at
pleasure to draw in and discharge into the firing chamber or port and cylinder air
to cleanse the same and also to drive out the result of combustion, the space between
the second piston and the cover of the cylinder is used to draw in firing mixture
and discharge the same into the firing port and cylinder after they have been
cleansed by the air. The air remaining in the cylinder and port previous to the
introduction of the firing mixture is driven out by similar means to those described.
in our former Patent A. D. 1883, May 18th N° 2492 also the exhaust escapes at or
near the end of the stroke of the first or main piston. The exhaust or discharge
port may be governed by a valve worked from the shaft and placed in such a
position in the cylinder that the piston is allowed to return a portion of its stroke
before compressing the contents of the cylinder and chamber and so utilize the
further expansion of the gases resulting from the combustion of the firing mixture
The firing chamber or port is brought round from one end of the cylinder so that
the firing mixture from the cylinder at one end is conveniently discharged into the
firing chamber or port, and the slide for igniting may be worked direct from the
shaft

page_text: And in order that our Invention may be fully understood we shall now more
particularly describe the same and for that purpose shall refer to the several figures
on the annexed sheet of drawings the same letters of reference indicating
corresponding parts in all the figures.
Figure 1 is a plan of a gas motor engine constructed according to our Invention
Fig 2 is an end elevation of the engine Fig 3 is a side elevation of the engine
Fig 4 is a view in section of the end of a pump or cylinder shewing the tappet for
regulating the gas supply. Referring to Fig 1A is the cylinder of the engine (which
may be surrounded by a water jacket as usual) in which cylinder the pressure resulting
from the firing of the explosive charge imparts motion to the piston B fitted in the
said cylinder and connected by the rod C with the crank of the crank shaft D
mounted in bearings in the bed E of the engine and carrying fly wheels F F-In
the cylinder A of engine are fitted two pistons B and G the rod of piston G is
hollow and works on the rod of the main piston B, on the end of the hollow piston
rod H is fitted a crosshead I which is driven by means of one or two eccentrics or
cranks J J It will thus be seen that as the crank shaft revolves the piston G is
reciprocated in the cylinder A. the cranks J J are set nearly right angles with the
crank D so that the cranks J J and with them the piston G complete their outstroke
at the time that the main piston G has travelled half way in its instroke, the space
between the piston G and the cover serves as a pump and draws in the mixture of
gas and air into the space L of the cylinder, upon the return stroke of the piston G
this mixture is discharged into the firing chamber M expelling the air and the
result of the previous combustion out at the exhaust port N and as soon as the
main piston B makes its instroke and covers the exhaust opening N the air
remaining in the cylinder A is driven out by the incoming mixture by the port or
opening O the valve governing this port being raised or open at the time, to make
sure all the air is discharged some of the firing mixture is allowed to escape with
the air and this is conducted by the pipe P to the chamber Q and is drawn into
the space L at the next instroke of the piston G by this means the cylinder is
thoroughly emptied of all air and at the same time no gas or firing mixture is lost.
The piston B making its instroke continues also to discharge the firing mixture
which is in the cylinder A and nearest to itself, by the port O, the valve R
remaining open until the piston has passed the opening when the mixture is then
compressed and driven back into the chamber M so that the greatest possible
diffusion and equal mixture of gas and air exists in the cylinder, the mixture when
compressed is fired by means of the slide valve S and the resulting pressure acting
on the piston B and crank D the shaft revolves thus an impulse is obtained once
every revolution of the crank shaft, upon the outstroke of the piston B the valve R
is closed so that the pressure of the gases in the cylinder are exerted on the piston
until the exhaust port N is uncovered by the piston.
In gas engines which receive an impulse once in every two revolutions and in
which the firing mixture is drawn into the cylinder by the main piston on its
outstroke this Invention may be carried into effect by closing the port (by the
slide or other means) by which the gas or air or both are being admitted to the
cylinder, some time before the piston has terminated its outstroke, this will cause a
partial vacuum in the cylinder but no loss of power will result as when the crank
has turned the centre and commences its return stroke the pressure of the atmosphere
will by acting on the outer side of the piston give off the same amount of power as
was taken to form the partial vacuum on the outstroke with the advantage of
equalizing the speed of the engine, when the slide of the engine is arranged to close
the inlet ports as described the piston does not compress the mixture until some
portion of its instroke has been made when the mixture is compressed and ignited,
the resulting pressure being obtained from only a part of a full charge the pressure
in the cylinder when the piston reaches the end of its outstroke is rendered very
low thereby ensuring very great economy and the noise of the exhausting gas
scarcely perceptible.
Having now described and particularly ascertained the nature of our. said

page_text: Invention and the manner in which the same is or may be used or carried into effect
we would observe that what we consider to be novel and original and therefore
claim as the Invention secured to us by the hereinbefore in part recited Letters
Patent is
First The arrangement and combination of parts constituting the improved gas
motor engine substantially as hereinbefore described and represented in the
accompanying drawings
Second-In gas motor engines the device for regulating the supply of gas by a
movement from the pump piston or main piston substantially and in the manner
and for the purpose hereinbefore described
Third-In gas motor engines in which the charge of gas and air is compressed
allowing the piston after it has completed its stroke to return one fifth or more of
its stroke before commencing to compress the mixture, either by keeping the
exhaust or a discharge port open or by forming a partial vacuum in the cylinder
and so utilize the further expansion of the gases substantially as hereinbefore
described
In witness whereof we the said George Gordon Picking and William Hopkins
have hereunto set our hands and seals this sixteenth day of May in the year of
Our Lord One thousand eight hundred and eighty four.
GEORGE CORDON PICKING