IMPROVEMENTS IN GAS MOTORS
Year: 1883

page_text: LETTERS PATENT to Dugald Clerk, of Glasgow in the County of Lanark
North Britain, Engineer, for an Invention of "IMPROVEMENTS IN GAS
MOTORS"
PROVISIONAL SPECIFICATION left by the said Dugald Clerk at the Office
of the Commissioners of Patents on the 21st August 1883.
DUGALD CLERK, of Glasgow, in the County of Lanark, North Britain, Engineer,
"IMPROVEMENTS IN GAS MOTORS "
This Invention has for its object, by improved parts or appliances to obviate
the difficulty often experienced with various existing forms of gas motors in
getting them to start.
In carrying out the Invention the gas motor is provided with a receiver for
holding a combustible mixture of gas and air under pressure; and this receiver is
charged by the motor itself prior to its action being stopped. The receiver is made
to communicate with the motor through one or more pipes or passages and valves,
but a stop valve is fitted close to the receiver in addition to any other valves, for
the purpose of completely closing the receiver during the intervals when the motor
is not working, and to reduce the possibility of leakage to a minimum. In the
case of a gas motor having a displacing or compressing cylinder in addition to the
usual motor or explosion cylinder, the passage between the displacing and motor
cylinders has a branch communicating with the receiver and a three-way valve is
fitted at the junction of this branch with the main passage. This three-way valve
can be moved by means of a hand lever, and provision is also made for working
it from an eccentric or cam on the crank shaft by means of a gab link or other
connection which can be put into or out of gear as required. In the branch passage
leading to the receiver there is a check valve opening inwards when the receiver
is being charged, and a hand lever is provided for opening this valve when about™
to start the motor. On starting the motor the parts being put in suitable positions,
the gaseous mixture under pressure finds its way through the three-way valve to
the displacing cylinder and acting on the piston or plunger of that cylinder causes
it to turn the crank shaft to a certain extent. Then as the action proceeds the

page_text: three-way valve becomes shifted and the gaseous mixture passes from the displacing
cylinder to the motor cylinder in which latter its pressure acts so as to continue
the motion; and being ignited at a suitable period there is additionally developed
the motive power due to the explosion. If this is not sufficient to fairly start the
engine the action may be continued for a second stroke or oftener by allowing
the gaseous mixture under pressure from the receiver to again act first in the
-displacing cylinder and then in the motor cylinder. In order to freshly charge
the receiver, whilst the motor is running, the three-way valve is set in a position
in which it partially throttles the communication with the motor cylinder whilst
the communication to the receiver is open, the check valve being set free to act
and prevent the return of the gascous inixture from the receiver. Then at each
revolution of the crank shaft a portion of the air and gas drawn into the
displacing.cylinder will be forced into the receiver whilst the remainder will pass
to the motor cylinder to be therein ignited in the ordinary way.
In gas motors of the kind in which the front end of the motor cylinder is used
for drawing in and for displacing the gas and air the arrangements of valves and
passages will be similar to those described as for a motor with a separate displacing
or compressing cylinder. In gas motors of the kind in which the gas and air are
primarily drawn into the motor cylinder itself at each alternato out stroke, the
three-way valve may be arranged to admit the gaseous mixture under pressure
during what is ordinarily the drawing-in stroke so as to propel the piston or plunger
and turn the crank shaft instead of the piston or plunger expending power to draw
in the air and gas. Or the gaseous mixture under pressure from the receiver may
be admitted to act during the first part of what would ordinarily be an explosion
stroke, means being provided to cause the ignition to take place after the communi-
cation with the receiver has been closed and at a later period of the stroke than
that at which the ignition is effected in the ordinary working of the motor.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Dugald Clerk in the Patent Office on the 20th February 1884.
DUGALD CLERK, of Glasgow, in the County of Lanark, North Britain, Engineer
IMPROVEMENTS IN GAS MOTORS
""
My said Invention has for its object, by improved parts or appliances to obviate
the difficulty often experienced with various existing forms of gas motors in getting
them to start. And in carrying out my Invention I provide the gas motor with a
receiver for holding a combustible mixture of gas and air under pressure; and
this receiver is charged by the motor itself prior to its action being stopped. The
receiver is made to communicate with the motor through one or more pipes or
passages and valves, but a stop valve is fitted close to the receiver, in addition to any
other valves, for the purpose of completely closing the receiver during the intervals
when the motor is not working, and to reduce the possibility of leakage to a
minimum. My improved starting apparatus is applicable to various kinds of gas
motors I have however shown it on two accompanying sheets of explanatory
drawings, as applied, under various modifications, to gas motors of the kind described
in the Specification of Letters Patent granted to me and dated 14 March 1881.
(N°. 1089).
In the motor referred to, and which is fully described in my said earlier
Specification, there is a displacing or compressing cylinder in addition to the usual
motor or explosion. cylinder; and for the purposes of my present Invention a
pipe is provided to communicate between the inner end of the displacing cylinder
or the passage therefrom to the motor cylinder and the reservoir and in this pipe
there is a valve which is ordinarily kept closed by a spring but which can be
lifted by the gaseous mixture when being charged into the reservoir, and which is
opened by means of a rod and hand lever when the gaseous mixture in the
receiver is to be used for starting the motor. When about to stop the working of
the motor and to charge the receiver in readiness for starting again, the main load
or a large part of it being thrown off a valve which may be arranged in various
ways as hereinafter more particularly described is adjusted or held so as to throttle
or partially throttle the communication from the displacing cylinder into the motor
cylinder, and then at each revolution of the crank shaft all or a portion of the air
and gas drawn into the displacing cylinder will be forced into the receiver.
Figures, 1, to 5, on sheet, 1, of the accompanying drawings represent one
modification of my improved starting apparatus, figures, 1, and 2, being enlarged
sections as at right-angles to each other of a three-way valve employed in this
modification. Figure, 3, is a plan of the motor, and figures, 4, and 5, are end and
side elevations, but with various parts of the motor omitted as not requiring
explanation in connection with my present Invention. The parts of the gas motor
shown are, a part of the base or bed frame, 1, the motor cylinder, 2, with the
piston guides, 3, and the displacing cylinder, 4, with the passage, 5, therefrom to
the valve box, 6, which last is below the back end of the motor cylinder. The
crank shaft, connecting rods, gear for working the ignition slide and other parts
are not shown. A receiver, 7, for the gaseous mixture is shown as placed within
the bed, frame, 1, but it may be placed in any convenient situation, being connected
with the motor by a pipe, 8. On this receiver pipe, 8, there is a stop valve, 9,
close to the receiver, 7, and at any convenient part of the pipe, 8, there is a valve
box, 10, which is shown enlarged and in section in figure, 6, on sheet, 2, of the
accompanying drawings. This valve box contains a check valve, 11, acted on by a

page_text: spring, and this valve is opened by the gaseous mixture when entering by the
inlet, 12, on its way to the receiver, 7, but closes and prevents the return of the
gaseous mixture except when it is specially opened for the purpose of starting the
engine. For this purpose a spindle, 14, is provided which works through a stuffing
box and is at its outer end connected to a hand lover, 15, centered on a bracket. The
inner end of the spindle, 14, is of a reduced size and touches the check valve, 11,
when this valve is closed so that on the spindle being thrust inwards it will open
the valve; and a spring is applied to the shoulder on the spindle to move it
outwards again whenever the pressure is taken off the hand lever, 15. At the
junction of the branch pipe, 8, leading to the receiver, with the passage, 5, between
the displacing cylinder; 4, and motor cylinder, 2, there is fitted a three-way valve
box, 24, and valve, 25, shown enlarged in figures, 1, and 2. This three-way
valve, 25, can be moved by means of a hand lever, 26, and provision is also made
for working it from an eccentric or cam on the crank shaft by means of a gab
link or other connection, and operating through a rocking shaft, 27, having
levers 28, 29, at its ends. With the three-way valve, 25, in the position in which
it is shown in figures, 1 and 2, there is a clear passage through from the displacing
cylinder, 4, to the motor cylinder, 2, but on turning the valve a quarter round the
port, 30, communicating with the receiver pipe, 8, is made to communicate with
the displacing cylinder or the motor cylinder accordingly as the valve is turned in
one direction or the other.
On starting the motor, the parts being put in suitable positions, the gaseous
mixture under pressure from the receiver, 7, finds its way through the three-way
valve, 25, to the displacing cylinder, 4, and acting on the piston or plunger of that
cylinder causes it to turn the crank shaft to a certain extent. Then as the action
proceeds the three-way valve, 25, becomes shifted and the gaseous mixture passes
from the displacing cylinder, 4, to the motor cylinder, 2, in which latter its pressure
acts so as to continuo the motion; and being ignited at a suitable period, there is
additionally developed the motive power due to the explosion. If this is not
sufficient to fairly start the engine the action may be continued for a second stroke
or oftener by allowing the gaseous mixture under pressure from the receiver, 7,
to again act first in the displacing cylinder, 4, and then in the motor cylinder, 2.
In order to freshly charge the receiver, 7, whilst the motor is running, the three-
way valve, 25, is set in a position in which it partially throttles the communication
with the motor cylinder, 2, whilst the communication to the receiver, 7, is open,
the check valve, 11, being set free to act and prevent the return of the gaseous
mixture from the receiver. Then at each revolution of the crank shaft a portion
of the air and gas drawn into the displacing cylinder, 4, will be forced into the-
receiver, 7, whilst the remainder will pass to the motor cylinder; 2, to be therein
ignited in the ordinary way.
A second modification of my improved starting apparatus is shown on alect, 2,
of the accompanying drawings. Figure; 6, is an enlarged section of the check and
starting valve, 11, herein before referred to; and figure, 7, is an enlarged section
showing the application of a modified device to be used when charging the
receiver, 7. Figure, 8, is a plan of the motor and figures, 9, and 10, are end and
side clevations. The saine reference numerals are used throughout the figures of
both sheets of drawings to mark the same or like parts wherever repeated.
In this second modification the arrangement of the check and starting valve, 11,
and details connected with the receiver, 7, remain the same as in the first modi-
fication; there is however shown leading from one end, 16, of the valve box, 10, a
small tube, 17, connected to a pressure gauge, 18, which may be placed in any
convenient position and which may of course be used in the first or any modification.
In the main valve box, 6, there are two check valves, a lower one through which
air and gas are drawn through the pipe, 5, into the displacing cylinder, 4, when its
piston or plunger is moving outwards in the ordinary working of the engine, and
an upper one through which the mixture of gas and air passes from the displacing

page_text: cylinder, 4, through the pipe, 5, into the motor or explosion cylinder, 2, This
upper check valve, 19, with its seat and other parts is shown enlarged and in
section in figure, 7. A piston or disk, 20, being fixed on the spindle of the valve, 19,
is availed of for limiting the extent of opening of the valve when the engine is
being worked so as to charge the receiver, a bolt or slide, 21, made with a rod
which works through a stuffing box and has a handle, 22, on its outer end, being
provided and arranged to work through a slot so as to project inwards over the
piston or disk, 20, of the valve. A spring, 23, is applied to the spindle of the
bolt, 21, to move it out again after being pushed in; and all that is necessary
when wishing to charge the receiver is to push inwards the handle, 22, of the bolt
and hold it in until the pressure gauge, 18, shows that the receiver has been
charged up to the desired pressure.
In figure, 11, sheet, 2, a still simpler and practically more convenient arrange-
ment of valve is shown (in enlarged section) for throttling or closing the
passage, 5, leading from the displacing cylinder, 4, to the motor cylinder, 2, In
this modification a simple flap valve, 31, is introduced in the passage, 5, being
fixed on and controlled by a spindle fitted externally with a hand lever. During
the ordinary working of the motor the flap valve, 31, lies in the position indicated
by dotted lines, in a recess, but when charging the receiver it is turned up to close
or nearly close the passage, 5, The attendant operator watches the motion of the
motor, and when he observes the speed to diminish too much he opens the valve to.
allow a sufficiently large charge to pass to the motor cylinder for increasing the speed
again and then again closes the valve and allows the freshly acquired momentum
to pump the gaseous mixture into the receiver, 7, by means of the piston of the
displacing cylinder, 4. The operator continues in this way occasionally opening
the valve, 31, as required until the desired pressure is attained in the receiver.
In gas motors of the kind in which the front end of the motor cylinder is used
for drawing in and for displacing the gas and air the arrangements of valves and
passages will be similar to those described as for a motor with a separate displacing
or compressing cylinder. In gas motors of the kind in which the gas and air are
primarily drawn into the motor cylinder itself at each alternate out stroke, the
three-way or other equivalent valve may be arranged to admit the gaseous
mixture under pressure during what is ordinarily the drawing-in stroke so as to
propel the piston or plunger and turn the crank, shaft instead of the piston or
plunger expending power to draw in the air and gas. Or the gaseous mixture
under pressure from the receiver may be admitted to act during the first part of
what would ordinarily be an explosion stroke, means being provided to cause the
ignition to take place after the communication with the receiver has been closed
and at a later period of the stroke than that at which the ignition is effected in the
ordinary working of the motor.
Having thus particularly described my said Invention and the manner of
performing the same I have to state that I do not restrict myself to the precise
details herein described or delineated but that what I believe to be novel and
original and claim as the Invention secured to me by and in terms of the herein-
before in part recited Letters Patent is :-
1. The combination with the ordinary parts of gas motors, of starting apparatus
consisting of a receiver to contain a combustible gaseous mixture under pressure,
a connecting pipe, and a valve which is an ordinary check valve for preventing the
return of gas passing through it when the receiver is being charged, but in
connection with which there is also a spindle and hand lever for opening it for the
purpose of starting the engine as herein before described.
2. The combination with a cylinder and a piston or plunger which in the
ordinary working of the engine draws in gas and air, of means or apparatus
causing gas under pressure to impart power to the said piston or plunger for the
purpose of starting the engine, the said means or apparatus consisting of the parts
mentioned in the first claim.

page_text: 3. The combination with the check and starting valvo (11) of any suitable
valve (31) or equivalent device for throttling or closing the passage for leading the
combustible gasoous mixture to the motor cylinder substantially as hereinbefore
described.
In Witness whereof I, the said Dugald Clerk have hereunto set my hand and
seal this twentieth day of February in the year of our Lord One thousand eight
hundred and eighty-four,
DUGALD CLERK (L.S.)