IMPROVEMENTS IN GAS MOTOR ENGINES
Year: 1884

page_text: PROVISIONAL SPECIFICATION.
I, JOHN FIELDING, of the Atlas Works, Gloucester, in' the County of Gloucester
Engineer do hereby declare the nature of my invention for "IMPROVEMENTS IN
GAS MOTOR ENGINES" to be as follows:-
This invention relates to improvements in gas.motor engines and has special
reference to engines constructed according to specifications Nº 532 of 1881, Nº 994
of 1882 and N° 3070 of 1883.
In engines constructed according to the present invention, the charge of gas and
air is introduced to the acting cylinder through an annular port which is uncovered.
by the piston when the latter is near the end of its acting stroke, as set forth in
the above named specifications. For the purposes of igniting and exhausting the
charges, and for controlling the speed of engines constructed in accordance with
this invention I prefer to employ the means described in the specification of patent
No 3070, 1883.
In lieu of utilizing the front end of the cylinder as a charging pump as described
in patent specification No 532, 1881. I provide an additional cylinder of larger
diameter than the acting cylinder, the larger cylinder is placed in front of and in
the same axis as the acting cylinder, within the large cylinder works a suitable
piston connected to the acting piston by means of a trunk of slightly less diameter
than the acting piston. The large cylinder and piston act as a charging pump, its
effective area being equal to the difference between relative areas of the two
pistons. The effective area is preferably made larger than that of the acting
piston. The annular port in acting cylinder is alternately placed in communication
with it, and with the charging pump, by the acting piston passing over it.
In connection with the annular port I provide a reservoir and a gas supply
valve. By means of a valve which may be called the main valve the annular port
is placed alternately in communication with the atmosphere and gas inlet, and
with the reservoir.
The action of the engine is as follows, viz, assuming that the engine has been
started, when the pistons are near the commencement of their forward stroke, the
charging pump is placed by means of the annular port and main valve, in
communication with the atmosphere and also with the gas supply. A mixed
charge of gas and air is drawn into the pump as the piston advances and as it has
to pass through the annular space between the piston trunk and the acting cylinder
13

page_text: it becomes thoroughly mixed. Shortly before the acting piston in its advance,
closes the annular port to the charging pump, the gas supply is shut off, when air
only is admitted, this serves to clear the annular port of explosive mixture and to
fill it and the passages in connection therewith with air, so that when the acting
piston subsequently opens the annular port on the acting cylinder side, no
premature explosion can take place, a barrier of atmospheric air being placed
between the hot products of combustion and the fresh explosive charge which
enters from the reservoir. After the main piston on its return or compressing
stroke has re-closed the annular port to the acting cylinder and re-opened it to the
charging pump, the latter delivers the charge drawn in during the previous
forward stroke, into the reservoir, the valve being in a suitable position for that
purpose, when the pistons arrive at the end of the return stroke the valve closes
the communication between the annular port and the reservoir and opens the port
leading to the atmosphere and the gas supply, this completes the cycle of operations.
By preference I construct the valve in a cylindrical form, it receives a recipro-
eating endwise motion from an eccentric or equivalent means. It is also capable of
being turned around its axis through a certain angle for the purpose of regulating
the admission of gas, a tappet valve is arranged to work within the slide valve, for
the supply of gas, suitable ports in the valve casing leading into the chamber
within which the tappet valve works. Motion may be imparted to the tappet
valve by means of an arm formed on the eccentric rod which works the slide valve,
the motion imparted being at right angles to the motion of the slide valve. The
oscillation of the cylindrical slide valve serves to regulate the period during which
gas is admitted for the purpose of controlling the speed of the engine.
The by-pass valve described in the Specification Nº 3070 of 1883 is employed
for the purpose therein set forth and in the present instance is operated by the
slide valve above described which is arranged to strike a tappet lever connected to
the by-pass valve spindle. The portion of charge passed through valve is allowed
to escape into a chamber from which the charging pump draws.
The governor employed is constructed upon the same principle as that described
in specification No 3070, of 1883, but in lieu of using a straight projection on the
governor spindle for the roller to work upon. I prefer to make it of a suitably
covered form, by which means the compensating link is eliminated, the roller being
pivoted upon the gyrating weighted arin. By preference I carry the curved path
upon both sides of the spindle and employ two weighted arms and rollers, one on
each side of the governor spindle.
Dated this Seventh day of February 1884.

page_text: I, JOHN FIELDING of the Atlas Works Gloucester, in the County of Gloucester
Engineer do hereby declare the nature of my invention for "IMPROVEMENTS: IN
GAS MOTOR ENGINES" and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement:—
This invention relates to improvements in gas motor engines and has special
reference to engines constructed according to specifications. No 532 of 1881, N° 994
of 1882, and Nº 3070 of 1883.
In engines constructed according to the present invention the charge of gas and
air is introduced to the acting cylinder through an annular port which is uncovered
by the piston when near the end of its acting stroke as set forth in the above
named specifications. For the purpose of igniting and exhausting the charges, and
for controlling the speed of engine constructed in accordance with this invention
I prefer to employ the means described in the specification of patent Nº 3070 1883.
In lieu of utilizing the front end of the cylinder as a charging pump as described
in patent specification No. 532, 1881, I provide an additional cylinder of larger
diameter than the acting cylinder, the larger cylinder is placed in front of and in
the same axis as the acting cylinder, within the large cylinder works a suitable
piston connected to the acting piston by means of a trunk of slightly less diameter
than the acting piston. The large cylinder and piston act as a charging pump, its
effective area being equal to the difference between relative areas of the two
pistons. The effective area is preferably made larger than that of the acting.
piston. The annular port in acting cylinder is. alternately placed in communication
with it, and with the charging pump, by the acting piston passing over it.
In connection with the annular port I provide a reservoir and a gas supply valve.
By means of a valve which may be called the main valve the annular port is
placed alternately in communication with the atmosphere and gas. inlet, and with
the reservoir.
The action of the engine is as follows, viz, assuming that the engine has been
started, when the pistons are near the commencement of their forward stroke,. the
charging pump is placed by means of the annular port and main valve, in
communication with the atmosphere and also with the gas supply. A mixed
charge of gas and air is drawn into the pump as the piston advances and as it has.
to pass through the annular space between the piston trunk and the acting cylinder
it becomes thoroughly mixed. Shortly before the acting piston in its advance,
closes the annular port to the charging pump, the gas supply is shut off, when air
only is admitted, this serves to clear the annular port of explosive mixture and to
fill it, and the passages in connection therewith with air, so that when the acting
piston subsequently opens the annular port on the acting cylinder side, no
premature explosion can take place, a barrier of atmospheric air being placed
between the hot products of combustion and the fresh explosive charge which
enters from the reservoir, after the main piston on its return or compressing stroke
has reclosed the annular port to the acting cylinder and re-opened it to the
charging pump, the latter delivers the charge drawn in during the previous
forward stroke, into the reservoir, the valve being in a suitable position for that
purpose, when the pistons arrive at the end of the return stroke the valve closes
the communication between the annular port and the reservoir and opens the
port leading to the atmosphere and gas supply, this completes the cycle of
operations.

page_text: "
DESCRIPTION OF THE DRAWINGS.
Figures 1. Shews a longitudinal vertical section of a gas engine constructed
according to my invention.
Figure 2. Shews a plan of same and Figure 3 a section to an enlarged scale of
the slide valve for distributing the air and gas before they enter the acting cylinder.
Figure 4, shews a cross section of valve.'
.
In Figures 1 and 2 A is the working cylinder B the working piston, C the
charging pumps,; D the pump piston connected to working piston B by trunk E.
F the connected rod, G the crankshaft, H the engine bed in which is preferably
formed the réservoir I, Jis the annular port in working cylinder, K a pipe
connecting port J.with valve box L
Referring to Figures 3 and 4 L is the valve box. M the slide valve, which
though shewn of cylindrical form may be made of any other suitable section, N is
the air inlet port, O the port leading to the pipe K, Figures 1 and 2, P is the port
leading to the reservoir I Figure 1. The cavity m in valve M alternately places
the port O in communication with N and P, Q is the gas inlet valve held upon its
seat by the pressure of a spring and operated through the link R, by a lever
connected to eccentric strap T, U is the gas inlet passage,. V the governor driven
by suitable means from the main crankshaft.
"..
.
The action of the engine is as follows. During the greater part of the forward
stroke of pistons B and D, air enters through port N and cavity m, gas also
entering through the passage U and valve Q and small ports connecting the latter
with cavity m the air and gas mixing as they enter port O. into pipe. K, annular
port J, and pump C, the trunk E being smaller than the working cylinder to allow
sufficient passage for the air and gas. Shortly before the piston B covers the
ports J, the gas is cut off air only being admitted, thus clearing the annular port J.
and pipe K of all combustible mixture: "As soon as the annular port is covered by
the piston, the port N is closed and O is put in communication with P. At the
same time the piston B uncovers the ports Jupon the other side thus placing the.
working cylinder in communication with the reservoir I through the pipe' K,
port O, cavity m, and port P. The charge of combustible mixture compressed into
reservoir by the previous return stroke of, piston D thus escaping from the reser-
voir into the working cylinder, the waste products of the previous explosion
being expelled through the exhaust pipes as described in 'the specifications herein-
before referred to. Upon the piston passing the ports J,.on its return stroke the
combustible mixture in pump D is forced through ports J, pipe K, port O, cavity m,
and port P into reservoir I. As soon as the piston reaches the end of its return or
compressing stroke, the valve closes port P, opens port N and the cycle of operations
is re-commenced as before."
·
3 1 "
"
In lieu of regulating the speed of the engine by varying the amount of gas
admitted I prefer to cut off the supply entirely, therefore instead of causing the
valve M to oscillate as indicated in my provisional specification, the link R is raised
by the governor so as to miss the gas valve spindle whenever the engine exceeds
its normal speed,
Having now particularly described and, ascertained the nature of, my said
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