IMPROVEMENTS IN GAS ENGINES
Year: 1879

page_text: LETTERS PATENT to Martin Benson, of No. 9, Southampton Buildings, London,
for the Invention of "IMPROVEMENTS IN GAS ENGINES." A communication
from abroad by Alexander Kirk Rider, of Walden, Orange County, State of
New York, United States of North America.
Sealed the 28th November 1879, and dated the 3rd June 1879.
PROVISIONAL SPECIFICATION left by the said Martin Benson at the Office
"IMPROVEMENTS
of the Commissioners of Patents on the 3rd June 1879.
MARTIN BENSON, of No. 9, Southampton Buildings, London.
IN GAS ENGINES." A communication from abroad by Alexander Kirk Rider, of
Walden, Orange County, State of New York, United States of North America.
My improvements relate to that class of engines in which the power is developed
by the combustion of mixed gas and air in the motive cylinder of the engine, the
mixed air and gas being used under compression.
The object of these improvements is to simplify and increase the efficacy of this
class of motors.
These improvements consist in the employment of several novel devices and
arrangements as applied to the above named class of motors as follows :—
1st. In a gas engine, the construction or combination of a compression and a
power cylinder with appropriate parts so arranged that any desired degree of
compression may be applied to the mixed gas and air without the necessity of
using a reservoir or an inlet valve for the motive cylinder; this arrangement also
provides for positive power in the engine at each revolution, thereby simplifying
the machine and giving greater power as compared with the size of the engine.
2nd. Separate compression of the gas and air in proper proportions and mixing
them after compression, whereby all risk of explosion is avoided.
3rd. An arrangement by which any desired proportional and exact quantity of
gas is used in each charge of air, thereby ensuring maximum economy of gas.
4th. Compression of the air and also of the gas in cool cylinders, and ignition
the mixed gas and air in a cylinder of considerably elevated temperature, thereby
utilizing the greatest amount of power and avoiding the necessity of "water
Price 8d1

page_text: jacketing" the motive cylinder, which has also the effect of reducing the amount of
power absorbed in compression to a minimum.
5th. Perfect regulation of speed, by causing the gas supply pump to become
inoperative when the speed is too high.
6th. The use of leather packings, thereby lessening the cost of construction and
making the machines more perfect with greater facility.
7th. A novel construction of the igniter by which it is much easier made, and
is more perfect, durable, and reliable, and also requires less power to operate it.
8th. The employment of effective means to "wash out" the carbonic acid or burnt
air from the hot or motive cylinder at each revolution, thereby ensuring more
perfect combustion.
9th. The ready adjustment of all important operating parts, by which the amount
of compression, the quantity of air used at each revolution, the proportional
quantity of gas, and time of ignition may be varied at pleasure with great
facility.
10th. The adaption of a regenerator or a regenerating surface to gas engines,
whereby much of the waste heat is utilized.
11th. The peculiar construction of the gas pump by which only a portion of its
stroke is effective, thereby causing the gas to be delivered into the engine at the
proper time and in exact prearranged quantity.
My improvements may be adapted to engines of various types of construction,
but I prefer as most convenient the arrangement and construction of an engine
approximating to that which I at present use as a hot air engine, namely, two
vertical cylinders with about equal stroke and area arranged parallel to each other
a short distance apart, and connected together at their upper ends by their flanges
and at the lower ends by a channel or air passage leading from one to the other.
These two cylinders are preferably cast together so as to form one casting. These"
cylinders are open at their upper ends and fitted with suitable pistons, which are con-
nected "direct" by links or connecting rods to the cranks on the main shaft, which
in its turn is supported on pillar blocks based on the upper ends of the cylinders,
and the main shaft is placed in such position that the cranks at or near its ends
will come over the centre of each cylinder. The main shaft also carries the fly
wheel, pulleys, and eccentrics to work the valve motion and igniter. One of the
cylinders above mentioned is the power or motive cylinder, the other is the com-
pression cylinder, and, as before stated, both cylinders are connected together at the
top ends by continuous flanges, and at the lower ends by a connecting passage way
through which the cold air flows in its way from the compression to the motive
cylinder. For convenience in description I call the motive and compression
cylinder hot and cold cylinder respectively.
The cold or compression cylinder is simply an air pump. It has an inlet valve
at its lower end to admit fresh air, and it has also a delivery valve in the passage
way connecting the cylinders to prevent the reflux of the air at the upstroke, both
these valves are automatic in their action.
The motive or hot cylinder is extended downwards some distance below its
normal stroke, and has fitted to it a correspondingly extended piston for the
purpose of allowing a considerable rise in the temperature of the lower end of the
cylinder and piston to occur without causing injury to the packings or lubricants
of the motive piston. The connecting passage way between the hot and cold
cylinders enters into an annular rebate or recess in the hot cylinder, some distance
from its lower end.
This rebate receives the cold air from the passage way connected to the cold
cylinder and distributes it around the extended portion of the hot piston, which
is made of less diameter at this place to allow a passage for the air in a thin
annular sheet.
The hot surfaces of the pistons and cylinders thus act as a regenerator.
This construction utilizes the greater part of the accumulated beat of the com-
bustion by heating the inflowing air; it also serves to confine the heat to the

page_text: lower part of the hot cylinder, and prevents the upper part from getting incon
veniently hot.
In former and also in existing gas engines it has been deemed necessary to
"water jacket
"this and the lower portion of the engine, causing a considerable
loss in effect, as the resulting expansion of combustion is lessened by contact of the
gases with cold surfaces.
I prefer to use no water or other means to keep the lower part of the motive
cylinder cool, but allow it to heat up to any convenient extent, thereby utilizing
to the utmost the expansive force of the gases. However, water jackets or other
known means may be used to keep the cylinder and exhaust valve cool if found
necessary. The hot or motive cylinder is also fitted with an igniter to fire the
compressed charge of mixed gas and air, and it has an exhaust valve arranged in
its lower end to emit the burned air after its expansion and effect. Both the
igniter and exhaust valve are worked from eccentrics; no inlet valve however is
necessary, as the compression cylinder delivers its charge of air at each revolution
under proper compression and in correct time. The cranks, as before stated, are
fitted on the ends of the main shaft and are directly over their respective pistons.
They may be set at about right angles from each other circumferentially, or they
may be placed much nearer together even to complete coincidence. It is generally
best however to have the cranks about 45° apart, the crank of the hot or motive
piston being in advance in the direction of rotation.
The relative position of these cranks with respect to each other circumferentially
determines the amount of compression to which the air and gas will be subjected,
the compression being greatest when the cranks are coincident or acting in the
same plane and direction.
In that case however a certain amount of compression space would necessarily
have to be provided below the hot or motive piston beyond the limits of its down
stroke, to allow room for the compressed air and gas. The cranks being set at 45°
from each other obviates this necessity and gives a better result.
This arrangement allows of ready adjustment to any degree of compression
desired by altering the position of the cranks with relation to each other, as will
be readily seen on inspection.
The combustable gas is supplied to this engine by means of a small single acting
pump, preferably and most conveniently operated by an arm which projects from
the piston of the cold or compression cylinder, and this gas pump is attached to
the side of the cold cylinder with which it is arranged parallel.
Its construction is such that it delivers only a certain portion of its full
capacity at each down stroke, and this quantity is made variable at pleasure for
the purpose of varying the quantity of gas used at one revolution.
The means by which this change of delivery is effected in its simplest construc-
tion is as follows:-
The barrel of the pump is made somewhat longer than usually required for a
certain length of stroke, and at some given distance from the top of the pump
barrel a number of small holes or perforations are made through the pump barrel
into an annular belt or space connecting with the gas main direct without any
intervening valve.
The piston of the gas pump overruns this perforated portion of the pump barrel,
and on the descent of the piston a portion of the gas, namely, that contained
between the piston and the perforations, will be forced back into the main, and
consequently will not pass into the engine. This escaping or reflowing portion of
the gas contained in the gas pump may be varied in quantity by an adjustment
of the position of the pump piston when at the ends of its stroke. In other words,
by the length of the pump plunger and the relative distance its lower end traverses
above and below the perforated portion of the pump barrel.
Suitable means are provided to alter the length of the plunger, so as to make
this adjustment with facility.
The reason and object of using only a portion of the capacity of the gas pump in

page_text: partly to secure the above adjustment as to quantity of gas delivered, but mainly
because all the gas pumped into the engine at one revolution must be delivered in
less than one revolution, as otherwise a portion of the gas would escape with
the exhaust. In other words the gas should not begin to be pumped in before the
exhaust valve is closed, and it must be all in before ignition, which occurs about '/,
of a revolution after the closing of the exhaust valve, whereas to deliver the whole
stroke of the pump would necessarily embrace or include one half of one revolution.
The gas is by the action of the gas pump compressed to an equal degree with the
air in the cold or compression cylinder, and is conducted by a pipe to the annular
rebate in the hot or motive cylinder, or, if preferred, to a point lower down in the
motive cylinder, where meeting the inflowing current of air from the cold cylinder
it is thoroughly mixed with the air and ready for ignition. It will be observed
that both the gas pump and the compression cylinder are removed from the proximity
of the hot cylinder, and therefore not liable to become hot, a condition most
favourable to economical compression. The gas supply pump just mentioned has
the usual suction and delivery valves as common to single acting pumps, but the
suction valve has in addition a short rod or pin fitted into its chamber beneath,
and central with the suction valve, said pin projecting through the lower part
of the valve chamber sufficiently to allow an arm or short lever connected with the
governor to act on it by raising or lowering it to some extent vertically, and it is so
arranged that the raising of the governor balls will raise this pin and cause it to
come in contact with the suction valve, and raise it off its seat, thus preventing the
operation of the gas supply pump as long as this position of the governor is main-
tained. On the subsidence of the governor balls the pin will be withdrawn suffici-
ently to allow the closure of the suction valve, and the pump will operate as usual.
By this means the speed of the engine is efficiently regulated.
The igniter is attached to the lower part of the hot or motive cylinder. Its con-
struction may be of the usual type, but 1 prefer to use the following arrangement
and construction of parts:-
I employ for this purpose simply a lamp with an oil reservoir contained in the
body of the slide of the igniter, and a wick inserted in a tube placed in a recess in
the said slide. The reciprocating motion of the slide, by means of the eccentric,
brings this recess and lighted wick opposite to an opening leading into the hot or
motive cylinder, which ignites the charge at each instroke, and the wick is kept
lighted by a small continuous jet of gas, which relights the wick at each outstroke,
when the recess and wick are brought outside of the contact surfaces of the face and
sides into the open air.
I also employ a peculiarly shaped slide in the igniter to lessen the friction and
avoid the use of springs and other delicate adjustinents. For this purpose I make
the slide of the igniter of a wedge shape in vertical section, its thickest edge being
upwards. The face side is kept upright or square to the line of the cylinder, but
the hack is sloping outwards and upwards, and the whole slide is enclosed in a
rigid frame or case corresponding in interior form to the exterior of the slide, but
somewhat deeper, so as to allow the wedge shaped slide to find its correct bearing
by setting downwards till it engages both face and back accurately.
and gib at the wide edge of the slide keeps it down into its place.
A set screw
The slide in the longitudinal section is of course parallel to allow of its recipro-
cating motion. This conformation of the slide of the igniter may be applied with
advantage to an igniter using gas exclusively, and I can also, in connection with a
lamp and wick, use a circular taper plug with a partially rotating motion in place
of a rectilinear slide, but I prefer the latter. In both cold and hot cylinders I
prefer to use plunger or trunk pistons, and I also prefer to use leather packings, as
the beat at the ends of the cylinders is not excessive, and the leather packings are
easily made and readily kept in order.
A slight spring on the delivery valve of the gas pump prevents the escape of
gas from the gas main when the engine is temporarily stopped, and also cause the
regulating device to act more promptly.

page_text: The burnt air or carbonic acid is cleared from the hot cylinder as follows:-
Assuming the position of the cranks to be coincident, or nearly so, and supposing
both hot and cold pistons to be at the extremity of their upstroke, the hot cylinder
will be full of burnt air, and the cold cylinder will be charged with fresh air. The
engine being in motion the exhaust valve will open and allow the burnt air in the
hot cylinder to escape as the hot piston descends, but as the cold piston is also
descending the cold and fresh air will flow along the connecting passage way and
into the upper portion of the hot cylinder.
This influx of fresh air will drive the burnt air before it and downward through
the exhaust valve at the bottom of the hot cylinder in advance of the motion of
the hot piston, so that by the time both hot and cold pistons have arrived at half
stroke downwards, a volume of cold fresh air equal to the remaining space below
the hot piston will have been sent into the hot cylinder from above, thus effectually
clearing the space below the hot piston of burnt air.
At this point of the stroke the closure of the exhaust occurs and the compression
begins.
The gas pump also has begun to deliver its charge of gas under a like degree of
compression as that existing in the cold cylinder, and as the motion of both pistons
progresses the air in the cold cylinder and the gas in the gas pump will be forced
into the hot cylinder and into the space below the hot piston. A little past the
lower centre the ignition occurs, and with the consequent expansion of the mixed
air and gas in the hot cylinder, and the upward motion of both hot and cold pistons
a new charge of fresh air is taken into the cold cylinder, and a charge of gas into
the gas pump to repeat the operation at the next revolution. For the sake of easy
description I have in the above example supposed the position of the cranks to be
coincident, but, as before mentioned, it is preferable to have them placed about 45°
apart, this position allowing the transfer of the compressed air from the cold to the
hot cylinder, to occur at the most desirable time. It also causes the most perfect
removal of the burnt air, and avoids the necessity of providing a considerable waste
space below the hot piston to contain the compressed air and gas.
The proper time for closing the exhaust is usually when the cold piston is as far
from its upper limit of stroke as the hot piston is from the lower limit of stroke,
but this may be varied to some extent.
If the exhaust is closed sooner more air will be used and more compression
obtained, but if later less air and less compression with the same position of the
cranks; this however cannot be varied far with advantage.
I do not confine myself to the exact construction and arrangement of parts
above described, as it is obvious that the improvements, substantially, as above
described, may be adapted to various modifications of parts without altering their
mode of operation or impairing their utility.
Instead of using a slide valve or cock in connection with the igniter a conical
valve may be employed for the same purpose, namely, for opening communication
between the igniter and cylinder; in such cases the igniter or jet of light may be
attached to a piston or valve made to work in a small cylinder or tube; this piston
is constructed to perform the double function of carrying the jet of light composed of
gas, oil, or a fluid lamp, and made to open the valve leading into the power cylinder
for igniting the charge by placing the jet of light in communication with the charge
of gas and air in the power cylinder. This valve piston is worked by an eccentric
similar to the igniting slide valve before described, or by any other known means
by power taken from the main shaft of the machine.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Martin Benson in the Great Seal Patent Office on the 29th
November 1879.
MARTIN BENSON, of No. 9, Southampton Buildings, London. "IMPROVEMENTS
IN GAS ENGINES." A communication from abroad by Alexander Kirk Rider, of
Walden, Orange County, State of New York, United States of North America.
My improvements relate to that class of engines in which the power is developed
by the combustion of mixed gas and air in the motive cylinder of the engine, the
mixed air and gas being used under compression,
The object of these improvements is to simplify and increase the efficacy of this
class of motors.
These improvements consist in the employment of several novel devices and
arrangements as applied to the above named class of motors, as follows:-
1st. In a gas engine, the construction or combination of a compression and a
power cylinder with appropriate parts so arranged that any desired degree of com-
pression may be applied to the mixed gas and air without the necessity of using
reservoir or an inlet valve for the motive cylinder. This arrangement also provides
for positive power in the engine at each revolution, thereby simplifying the machine
and giving greater power as compared with the size of the engine.
2nd. Separate compression of gas and air in proper proportions, and mixing
them after compression, whereby all risk of explosion is avoided.
3rd. An arrangement by which the desired proportional and exact quantity of
gas is used in each charge of air, theroby insuring maximum economy of gas.
4th. Compression of the air and also of the gas in cool cylinders, and igniting the
mixed gas and air in a cylinder of considerably elevated temperature, thereby
utilizing the greatest amount of power and avoiding the necessity of water jacketing
the motive cylinder, which has also the effect of reducing the amount of power
absorbed in compression to a minimum,
5th. The perfect regulation of speed by causing the gas supply pump to become
inoperative when the speed is too high,
6th. The use of leather packings, thereby lessening the cost of construction, and
making the machines more perfect with greater facility.
7th. A novel construction of the igniter, by which it is much easier made, and is
more perfect, durable, and reliable, and also requires less power to operate it.
8th. The employment of effective means to wash out the carbonic acid or burnt
air from the hot or motive cylinder at each revolution, thereby ensuring more
perfect combustion.
9th. The ready adjustment of all important operative parts, by which the amount
of compression, the quantity of air used at each revolution, the proportional quantity
of gas, and time of ignition may be varied at pleasure with great facility.
10th. The adaption in the generator surface to gas engines, whereby much of the
waste heat is utilized.
11th. The peculiar construction of the gas pump, by which only a portion of its
stroke is effective, thereby causing the gas to be delivered into the engine at the
proper time, and in exact prearranged quantity.
My improvements may be adapted to engines of various types of construction,
but I prefer, as most convenient, the arrangement and construction of an engine
approximating to that which I at present use as a hot air engine, consisting of
two vertical cylinders A, B, as represented by Figs. 1 and 2 in the accompanying
Drawings. Attached to the frame V by a flange h, cast on the cylinders as repre-
sented, the cylinders are made about equal stroke and area arranged parallel to each
other, a short distance apart, and connected together at their upper ends by their
flanges C, and at their lower ends by a channel or air passage D leading from one

page_text: to the other. These two cylinders are preferably cast together, so as to form one
casting. These cylinders are open at their upper ends and fitted with suitable
pistons E and F, which are connected direct by links or connecting rods G and H
to the cranks on the main shaft I, which is supported on pillar blocks based on the
upper ends of the cylinders, and the main shaft is placed in such a position that the
cranks at or near its ends will come over the centre of each cylinder, all as repre-
sented. The main shaft also carries the fly wheel, pulleys, and eccentrics to work
the valve motion and igniter L. One of the cylinders A above mentioned is the
power or motive cylinder, the other is the compression cylinder B, as before stated,
both cylinders are connected at their top ends by continuous flanges C, and at the
lower ends by a connecting passage way D through which the cold air flows in its
way from the compression cylinder B to the motive cylinder A. For convenience in
description I call the motive and compression cylinders hot and cold cylinders
respectively. The cold or compression cylinder B is simply an air pump. It has an
inlet valve J at its lower end to admit fresh air, and has also a delivery valve K in
the passage way D connecting the cylinders, to prevent the reflux of the air at the
upstroke. Both these valves are automatic in their action.
The motive or hot cylinder A is extended downwards some distance below its
normal stroke, and has fitted to it a correspondingly extended piston E for the
purpose of allowing a considerable rise in the temperature of the lower end of the
cylinder and piston to occur without causing injury to the packings or lubricants of
the motive piston. The connecting passage way between the hot and cold cylinders
enters into an annular rebate or recess, as represented, in the hot cylinder A some
distance from its lower end.
This rebate receives the cold air from the passage way D connected to the cold
cylinder B, and distributes it around the extended portion of the hot piston, which
is made of less diameter at this place to allow the passage for the air in a thin
annular sheet. The hot surfaces of the piston and cylinder thus act as a regenerator.
This construction utilizes the greater part of the accumulated heat of the com-
bustion by heating the inflowing air; it also serves to confine the heat to the lower
part of the hot chamber, and prevents the upper part from getting inconveniently
hot. In former and also in existing gas engines it has been deemed necessary to
water jacket this and the lower portion of the engine, causing a considerable loss
in effect, as the resulting expansion of combustion is lessened by contact of the
gases with cold surfaces.
I prefer to use no water or other means to keep the lower part of the motive
cylinder A cool, but allow it to heat up to any convenient extent, thereby utilizing
to the utmost the expansive force of the gases. However, water jackets or other
known means may be used to keep the cylinder and exhaust valve cool, if found
necessary.
The hot or motive cylinder A is fitted with an igniter L to fire the compressed
charge of mixed air and gas, and it has an exhaust valve M arranged in its lower
end to emit the burnt air after its expansion and effect through an exhaust pipe
connected to the valvo, not shown in the Drawings.
Both the igniters and exhaust valve are worked from eccentric N and O; no inlet
valve, however, is necessary, as the compression cylinder B delivers its charge of air
at each revolution under proper compression and in correct time. The cranks, as
before stated, are fitted on the ends of the main shaft, and are directly over their
respective pistons; they may be set at about right angles from each other circum-
ferentially, or they may be placed much nearer together, even to complete coincidence.
It is generally best, however, to have the cranks about 45° apart, the crank of the
hot or motive piston being in advance in the direction of rotation.
The relative position of these cranks with respect to each other circumferentially
determines the amount of compression to which the air and gas will be subjected,
the compression being greatest when the cranks are coincident, or acting in the
same plane or direction. In that case, however, a certain amount of compression

page_text: space would necessarily have to be provided below the hot or motive piston beyond
the limit of its down stroke to allow room for the compressed air and gas. The
cranks being set at 45° from each other obviates this necessity and gives a better
result.
This arrangement allows of ready adjustment to any degree of compression
desired by altering the position of the cranks with relation to each other, as will
be readily seen on inspection.
The combustible gas is supplied to this engine by means of a small single acting
pump P, preferably and most conveniently operated by an arm a, which projects
from the piston F of the cold or compression cylinder, and this gas pump is attached
to the side of the cold cylinder with which it is arranged parallel.
Its construction is such that it delivers only a certain proportion of its full
capacity at each down stroke, and this quantity is made variable at pleasure for
the purpose of varying the quantity of gas used at one revolution.
The means by which this change of delivery is effected in its simplest construc-
tion is as follows.-
The barrel of the pump is made somewhat longer than usually required for a
certain length of stroke and at some given distance from the top of the pump
barrel, a number of small holes b or perforations are made through the pump barrel
into an annular belt or space connecting with the gas main direct by a pipe C
without any intervening valve.
The piston of the gas pump overruns this perforated portion of the pump barrel,
and on the descent of the piston a portion of the gas, viz., that contained between
the piston and perforations will be forced back into the main through the pipe C, and
consequently will not pass into the cylinder A. This escaping or reflowing portion
of the gas contained in the gas pump may be varied in quantity by an adjustment
of the position of the pump piston when at the end of its stroke. In other words
by the length of the pump plunger and the relative distance its lower end traverses
above and below the perforated portion of the pump barrel.
Suitable means are provided to alter the length of the plunger so as to make
this adjustment with facility.
The reason and object of only using a portion of the capacity of the gas pump
is partly to secure the above adjustment as to quantity of gas delivered, but
mainly because all the gas pumped into the engine at one revolution must be
delivered in less than one half revolution, as otherwise a portion of the gas would
escape with the exhaust. In other words the gas should not begin to be pumped
in before the exhaust valve M is closed, and it must be all in before ignition, which
occurs about one third revolution after the closing of the exhaust valve, whereas
to deliver the whole stroke of the pump would necessarily embrace or include one
half of one revolution. The gas is by the action of the gas pump compressed to an 4
equal degree with the air in the cold or compression cylinder, and is conducted by a
pipe d to the annular rebate in the hot or motive cylinder, or if preferred, to a
point lower down in the motive cylinder A, where meeting the inflowing current
of air from the cold cylinder B, it is thoroughly mixed with the air and ready for
ignition. It will be observed that both the gas pump and the compression
cylinder are removed from the proximity of the hot cylinder and therefore not liable
to become hot, a condition most favorable to economical compression. The gas
supply pump just mentioned will have the usual suction and delivery valves
common to single acting pumps, but the suction valve has in addition a short
rod or pin e fitted into its chamber beneath and central with the suction valve,
said pin projecting through the lower part of the valve chamber sufficiently to
allow an arm or short lever connected with the governor R to act on it by raising
or lowering it to some extent vertically, and it is so arranged that the raising of
the governor balls will raise this pin and cause it to come in contact with tho
suction valve and raise it off its seat, thus preventing the operation of the gas
supply pump as long as this position of the governor is maintained. On the sub-
sidence of the governor balls, the pin e will be withdrawn sufficiently to allow the

page_text: closure of the suction valve, and the pump will operate as usual. By this moans
the speed of the engine is efficiently regulated. The igniter is attached to the lower
part of the motive cylinder A. Its construction may be of the usual type, but I
prefer to use the following arrangement and construction of parts.
I employ for this purpose simply a lamp with an oil reservoir contained in the
body of the slide L of the igniter, and a wick inserted in a tube placed in a recess
in the said slide.
The reciprocating motion of the slide L by means of the eccentric N brings this
recess and lighted wick opposite to an opening leading into the motive cylinder A
which ignites the charge at each instroke, and the wick is kept ignited by a small
continuous jet of gas, not shown, which relights the wick at each outstroke when
the recess and wick are brought outside of the contact surfaces of the face and
sides into the open air.
I also employ a peculiarly shaped slide L in the igniter to lessen the friction
and avoid the use of springs and other delicate adjustments. For this purpose I
make the slide of the igniter of a wedge shape in a vertical section as represented in
Fig. 1, its thickest edge being upwards. The face side is kept upright or square to
the line of the cylinder, but the back is sloping outwards and upwards, and the
whole slide is enclosed in a rigid frame or case corresponding in interior form to
the exterior of the slide L, but somewhat deeper, so as to allow the wedge shaped
slide to find its correct bearing by setting downwards until it engages both face
and back accurately. A set screw and gib at the wide edge of the slide keeps it
down into its place.
The slide in the longitudinal section is of course parallel to allow of its recipro-
cating motion. This conformation of the slide of the igniter may be applied with
advantage to an igniter using gas exclusively, and I can also in connection with a
lamp and wick use a circular taper plug with a partially rotating motion in place
of a rectilinear slide, but I prefer the latter. In both cold and hot cylinders I
prefer to use plunger or trunk pistons, and I also prefer to use leather packings for
the ends of the pistons, as the heat at the upper ends of the cylinders is not
excessive, and the leather packings are easily made and readily kept in order, but
other known modes of packing may be used if desired. A slight spring on the
delivery valve of the gas pump, not shown, prevents the escape of gas from the gas
main when the engine is temporarily stopped, and also causes the regulating device
to act more promptly.
The burnt air or carbonic acid is cleared from the hot cylinder as follows:-
Assuming the position of the cranks to be coincident, or nearly so, and supposing
both hot and cold pistons to be at the extremity of their upstroke, the hot cylinder
A will be full of burnt air, and the cold cylinder will be charged with fresh air.
The engine being in motion the exhaust valve M will open and allow the burnt
air in the hot cylinder to escape as the hot piston E descends, but as the cold
piston F is also descending, the cold and fresh air under it will flow along the
connecting passage way D and into the upper portion of the hot cylinder. This
influx of fresh air will drive the burnt air before it and downwards through the
exhaust valve M at the bottom of the hot cylinder in advance of the motion of the
hot piston, so that by the time both hot and cold pistons have arrived at half
stroke downwards, a volume of cold fresh air equal to the remaining space below
the hot piston, will have been sent into the hot cylinder A from above, thus
effectually clearing the space below the hot piston of burnt air. At this point
of the stroke the closure of the exhaust valve I occurs and the compression begins.
The gas pump P has also begun to deliver its charge of gas under a like degree
of compression as that existing in the cold cylinder, and as the motion of both
pistons progress the air in the cold cylinder B and the gas in the gas pump P will
be forced into the hot cylinder A and into the space below the hot piston E. A
little past the lower centre the ignition occurs, and the consequent expansion of the
mixed air and gas in the hot cylinder, and the upward motion of both hot and cold
pistons, a new charge of fresh air is taken into the cold cylinder B, and a charge of

page_text: gas into the gas pump to repeat the operation at the next revolution. For the sake
of easy description I have in the above example supposed the position of the cranks
to be coincident, but as before mentioned it is preferable to have them placed at
about 45° apart, this position allowing the transfer of the compressed air from the
cold to the hot cylinder to occur at the most desirable time. It also causes a more
perfect removal of the burnt air, and avoids the necessity of providing a considerable
waste space below the hot piston to contain the compressed air and gas. The
proper time for closing the exhaust is usually when the cold piston is as far from
its upper limit of stroke as the hot piston is from its lower limit of stroke, but this
may be varied to some extent.
If the exhaust valve M is closed sooner more air will be used and more com-
pression obtained, but if later less air and less compression with the same position
of the cranks; this however cannot be varied far with advantage.
Instead of using a slide valve or cock in connection with the igniter, a conical
valve may be employed for the same purpose, viz., for opening communication
between the igniter and cylinder. In such cases the igniter or jet of light may be
attached to a piston or valve made to work in a small cylinder or tube. This piston
is constructed to perform the double function of carrying the jet of light composed
of gas, oil, or a fluid lamp, and made to open the valve leading into the power
cylinder for igniting the charge by placing the jet of light in communication with
the charge of gas and air in the power cylinder. This valve piston is worked by an
eccentric similar to the igniting slide valve before described, or by any other known
means by power taken from the main shaft of the machine.
Figs. 3 and 4 represent an igniter similar to the one just described provided with
a conical valve.
There is an inner valve B one inch or one inch and a quarter in diameter; this
opens into the cylinder A, and has a long stem passing outward or downward about
three inches and a half long. There is also an outer valve M of a tubular shape
half an inch longer than the stem of the inner valve, and having a bottom or
piston C in it about one inch from its end, and into which is fastened a central tube
to act as a guide for the stem of the inner valve B which passes entirely and some
distance through the bottom of the outer valve, as through a simple cup leather
to keep it tight. This cylindrical valve may be about one and a half inch in
diameter, more or less, and has a spring H arranged below the piston C and acting
between it and a loose bottom a capable of being pressed upward a short distance
against the spring. The stem of the inner valve nearly touches this false or loose
bottom a, and the outer cap o gives facility to get any required tension on the spiral
spring H. A common arm or crank P worked by an eccentric from the main shaft
engages the projection on the loose bottom a as shown. This outer valve is held
concentrically by four wings or guides N, N, projecting from the bottom of the igniter
and bored out to fit the exterior of the outer cylindrical valve M. At one side is
the lighting jet 8, and there is a ring or shield b outside of the outer valve M to
keep the heat of the lighting jet and soot from acting on the outer valve. It will
be seen how this operates, assuming the wick and the outer valve M half or
three quarters of an inch down from the face. The action of the eccentric will
close the outer valve M by raising it up until it engages its face; on the further
motion of the eccentric the loose bottom a will be pressed in against the spring H
and will lift the inner valve B and ignite the charge. Of course the spring H will
have to be strong enough to stand the explosion, and the force of it will be held by
the eccentric, which at that place or time is in the most favorable position, viz., at or
close to one of its centres, and consequently under no motion of any amount, it is
in fact much the same as if an eccentric were used to punch or stamp the extreme
end of the stroke taking the strain, but in this case the valve is small and the
resistance not at all formidable. This plan is not open to the serious objections of
sliding hot and dry flat surfaces of great surface, it will keep tight even if red hot,
and wants no attention or oil, and is cheaply made and not at all likely to get out
of order.

page_text: If desired a jet of gas may be used instead of the wick and oil; this may be
effected by a flexible tube attached to the side of the cylinder valve M at any con-
venient part above the fixed piston.
The igniting chamber W is supplied with gas and air of proper proportions for
combustion by the pipes R and T. The air through the pipe R is taken from the
cylinder, and the gas through the pipe T from the gas pump P. The air and gas
properly combined is forced into the iguiting chamber at X. The igniter valve
arrangement may, if desired, be attached to the bottom of the power cylinder instead
of its side, as represented in Fig. 3.
I do not confine myself to the exhaust construction and arrangement of parts
above described, as it is not obvious that the improvements substantially as above
described may be adapted to various modifications of parts without altering their
mode of operation or impairing their utility.
The machine may be constructed to work in a horizontal or angular position
instead of vertical, if desired, by changing the various parts to suit the altered
position.
Having now described the nature of my improvements, and manner of con-
structing the same, what I claim as new, and desire to obtain Letters Patent for,
is,-
1st. The combination of a compression cylinder B and a motive cylinder A with
a gas pump P arranged and operating substantially as described.
2nd. The arrangement for the separate compression of the gas and air is suitable
proportions for one revolution, aud inixing them after compression, substantially as
described.
3rd. The construction and arrangement of the gas pump whereby a portion only
of the full capacity of the pump is delivered at one stroke, substantially for the
purposes described.
4th. A gas engine, the motive cylinder so constructed as to sustain a high
temperature at its inner end without injury to the other parts connected therewith,
substantially as described.
5th. A gas engine, the motive piston of which is prolonged at the inner end for
the purpose of allowing its inner end to sustain an elevated temperature without
transmitting an injurious degree of heat to the piston or packings, substantially as
described and represented.
6th. The igniter with its slide L constructed with a wedge like or V section, and
thicker at one edge than the other so as to be capable of nice adjustment in its case
by a slight movement across the line of its longitudinal travel, that is, towards its
thinnest edge, substantially as described and represented.
7th. The adaption and employment of a lamp and wick, or gas jet, or their
equivalent, in the igniter for the purpose of firing the charge, substantially as
described.
8th. The means employed to displace that portion of the burnt air in the hot
cylinder which is not expelled by the hot piston, said portion of the hot air being
blown out of the hot cylinder by the influx of the cold air from the compressed
cylinder B while the exhaust valve M is open, substantially as described and
represented.
9th. The employment of a regenerator or a regenerating surface between the
extension of the hot piston and the extended portion of the hot cylinder for the
purpose of heating the air in its passage to the lower or inner portion of the hot
cylinder, substantially as described.
10th. The means employed to regulate the speed of the engine by causing the
governor to prevent the closing of the induction valve of the gas supply pump for
a longer or shorter time, substantially as described.
11th. The general arrangement of a gas engine constructed and operated sub-
stantially as described.
12th. The construction and arrangement of the valves B and M and parts con-
nected therewith, as described and represented in Figs. 3 and 4, by which the charge

page_text: of gas and air is ignited in the power cylinders of gas engines, substantially in the
manner herein before described.
In witness whereof, I, the said Martin Benson, have hereunto set my hand
and seal, this Twenty eighth day of November, in the year of our Lord
1879.
MARTIN BENSON. (L.S.)