IMPROVEMENTS IN MOTOR ENGINES WORKED BY GAS OB COMBUSTIBLE VAPOUR AND AIR
Year: 1875

page_text: LETTERS PATENT to Charles Denton Abel, of No. 20, Southampton
Buildings, Chancery Lane, in the County of Middlesex, for the
Invention of "IMPROVEMENTS IN MOTOR ENGINES WORKED BY GAS OB
COMBUSTIBLE VAPOUR AND AIR." A communication from abroad by
Gottlieb Wilhelm Daimler, of Muelheim on the Rhine, in the
German Empire, Engineer.
Sealed the 27th April 1875, and dated the 8th January 1875.
PROVISIONAL SPECIFICATION left by the said Charles Denton Abel
at the Office of the Commissioners of Patents, with his Petition,
on the 8th January 1875.
I, CHARLES DENTON ABEL, of No. 20, Southampton Buildings,
Chancery Lane, in the County of Middlesex, do hereby declare the
nature of the said Invention for "IMPROVEMENTS IN MOTOR ENGINES WORKED
BY GAS OR COMBUSTIBLE VAPOUR AND AIR," to be as follows:-
This Invention relates to that class of engines wherein by an explosion
of a mixture of combustible gas or hydrocarbon vapour and air inside a
[₁

page_text: cylinder a partial vacuum is produced therein causing a working piston
to be propelled by atmospheric pressure.
According to the present improvements a water jacketted cylinder
open to the atmosphere at both ends contains, firstly, a working piston
connected by a piston rod, cross head, and connecting rod to an engine
shaft having a fly wheel; and secondly, two other pistons, one on cach
side of the said working piston. These latter pistons are loose in the
cylinder and are constructed very light and operate in the following
manner: Assuming the working piston to be at the end of its back
stroke resting closely against the back loose piston and with a space
intervening between it and the front loose piston, into which space an
explosive mixture of air and gas or petroleum vapour has been drawn
from an inlet valve, then on the ignition of the explosive mixture the
front loose piston will be propelled rapidly to the front end of the
cylinder, where it is retained by a contrivance to be presently described.
The gascous products of the explosion being cooled by their expansion
and by the cold water jacket of the cylinder, a partial vacuum will be
produced in the cylinder whereby the working piston and with it the
back loose piston will be caused by atmospheric pressure to travel
together towards the front end of the cylinder. Passing through the
working piston is a rod capable of sliding to and fro so as to project a
certain distance on the one side or the other side of the piston. As the
working piston approaches the front end of the cylinder, the said rod in
coming in contact with the front loose piston, and being also in contact
with the back loose piston arrests the motion of the latter, while the
working piston continues its motion to the end of its stroke. A space is
thus formed between the working piston and the back loose piston, into
which a fresh charge of gas and air is drawn. At the same time the
working piston in approaching the front loose piston forces out the
condensed products of combustion contained between them through an
escape valve in the side of the cylinder. When the working piston has
arrived at the end of its forward stroke being then situated close against
the front loose piston, which it has also moved so as to release it from
its fixed position as will be hereafter described, the charge of gas and
air between it and the back loose piston is ignited, whereby the back
loose piston is propelled to the back end of the cylinder, and the working
piston together with the front loose piston are caused to perform their
back stroke under atmospheric pressure as before described.

page_text: For retaining the loose pistons at the ends of the cylinder when they
have been propelled by the explosion as above described, the following
arrangement is employed:-The cylinder is slightly conically enlarged
at each end, and the pistons are formed with a conical surface upon
which is a loose conical ring formed in segments held together by a
small ring fitting in grooves in the segments. The segment ring is
connected to springs which tend to keep it at the smallest diameter of
the conical surface of the piston, but when the piston is propelled by the
explosion into the conical enlargement of the cylinder, and is there
suddenly arrested by the counterpressure of the atmosphere, the conical
segment ring in continuing its forward motion by virtue of its
momentum slides up the conical surface of the piston, and being thus
expanded wedges itself tight between such conical surface and the
conical surface of the cylinder, and thus the piston is held in position as
before described.
When the working piston in completing its stroke comes in contact
with the loose piston as before described it pushes the same somewhat
further outwards in the conically enlarged part of the cylinder, and the
segment ring being thus freed from its wedged position the springs will
cause it to resume its contracted position, and the piston will then be
loose and free to follow the working piston on its return stroke.
The loose pistons are made to work air-tight against the cylinder by
means of a packing consisting of a broad ring of leather held at its
middle against the circumference of the piston by a metal ring, so that
the pressure existing either on the one side or the other side of the
piston tends to press the ends of the leather ring against the cylinder in
a similar manner to an ordinary cup leather.
At each end of the cylinder is a yielding buffer ring, against which
the working piston presses the loose piston at the extreme end of its
stroke so as to ensure that all the products of combustion shall be forced
out from between the two pistons, and that they shall lie closely against
each other on the return stroke.
The arrangement of the valves and gear for admitting and cutting off
the supply of gas and air to and from the cylinder and for igniting the
explosive charge is as follows:-At each end of the cylinder is a valve
box communicating with a passage leading into the cylinder, and con-
taining a conical valve fitting on to a conical seating. This valve has a

page_text: stem of large diameter, which passes out through the end of the valve
box, and which has a central passage formed right through it, and
through the central part of the valve itself, through which passage the
requisite air for the explosive charge can enter when the valve is open.
Round the external part of the valve stem is formed an annular passage
having a nozzle by which it is connected by a flexible tube with the
supply of combustible gas. From this passage a number of small
channels extend along the stem of the valve, and open in the conical
part of the latter. Thus when the valve is open gas will issue from the
said channels, and air will issue from the before-mentioned central
passage into the valve box, whence the explosive mixture will pass into
the cylinder. When the valve is shut the supply of gas and air will be
simultaneously cut off. Behind the compartment of the valve box, into
which the gas and air issue, is a second compartment through which the
stem of the valve passes, and in which is a gas jet kept constantly
burning, air being supplied to the flame through a number of holes in
the casing, while a small chimney is provided on the top of the casing
to promote a draught for the flame. This second compartment can
communicate with the first-named compartment when the valve is in
the act of closing by means of an aperture surrounding the stem of the
valve, which aperture is closed by a cylindrical part of the valve when
this is open for the admission of gas and air.
Upon the stem of the valve inside the second compartment is further-
more formed a disc, the action of which is as follows:-Assuming the
valve to be open, and a charge of gas and air to have passed into the
cylinder, then on the valve moving towards its closed position it will
open the aperture of communication between the two compartments,
while at the same time the before-mentioned disc in moving towards the
said aperture will carry a portion of the flame from the gas jet through
the same into the first compartment, and it will then close the aperture,
thus cutting off the communication between the two compartments,
while the flame ignites the explosive mixture in the cylinder.
opening of the valves for the admission of gas and air to the cylinder at
the proper times is effected by cams or wipers on the engine shaft acting
on rods attached to the valves so as to force these open against the
action of a spring, the closing of the valves being effected rapidly by
such spring when a drop on the cam passes the end of the valve rod.
The
When the engine is worked by hydrocarbon vapour instead of coal

page_text: gas the liquid hydrocarbon is introduced in a small stream into a pipe
passing through the water jacket of the cylinder, so that the liquid
becomes vapourised by the heat of the warm water in the jacket as it
passes through the pipe, whence it issues in the form of vapour, together
with a certain quantity of air, through a flexible tube into the before-
described passages in the valve. Should any particles of the hydro-
carbon enter the passages of the valve in a liquid state they will become
vapourised before issuing into the valve box by the heat of the before-
mentioned gas or petroleum flame that serves to ignite the charge, and
which plays round and heats the stem of the valve.
When hydrocarbon vapour is employed it is also desirable to warm the
supply of air for the explosive charge, for which purpose it is also caused
to pass through a pipe situated in the water jacket of the cylinder,
whence it issues through a flexible tube into the before-mentioned
central passage of the valve.
For regulating the power of the engine the supply of combustible gas
or vapour is regulated by means of a governor in such manner that
should the speed of the engine be too great the supply of gas is entirely
cut off, and consequently the piston performs its strokes without any
explosion of gas and air occurring until by the reduction of the speed
the gas supply is again fully opened. For this purpose a valve is pro-
vided in the gas supply pipe, the stem of which is actuated by the balls
of a governor. On the end of the valve stem is a plate having on one
side a feather edge, which is presented towards the feather edge of a pro-
jection formed on the face of the bevil wheel on the engine shaft that
drives the governor. When the engine is running at its normal speed
the governor balls will keep the valve in its open position, in which
position the projection on the bevil wheel will pass underneath the plate
on the end of the valve stem, and will thus ensure that the valve is kept
fully open while the gas is passing into the cylinder. If, on the other
hand, the engine runs slightly above its normal speed, the governor balls
in expanding will move the valve stem somewhat downwards, whereby
the feather edge of its plate will be brought below the feather edge of
the projection on the bevil wheel, and this projection will consequently
pass with an inclined surface over the plate of the valve stem, thus
depressing the valve and entirely cutting off the gas supply. Thus it
will be seen that the cutting off of the gas supply for regulating the
power of the enginè is effected by the engine itself, the governor only

page_text: serving to bring the parts into action for this purpose. By the above-
described method of regulating the power of the engine the proportions
of gas and air employed for cach explosive charge are always constant,
and consequently the engine always works with its maximum effect.
In the gas supply pipe is also provided a flap valve, which is ordinarily
kept open by a weight consisting of a screw that can be screwed morc
or less into the valve, and thus by shifting its centre of gravity regulate
the extent to which it is kept open. Should by accident one of the
loose pistons become jammed in the cylinder so as to prevent it from
completing its in stroke with the working piston, the increased suction
produced in the cylinder by the increased space thus formed between
the working piston and loose piston will cause the said flap valve to be
closed more or less, and thus the introduction of a greater quantity of
gas into the cylinder than is required for the explosive charge will be
prevented.
For cooling the working piston and piston rod of the engine a cir-
culation of water is kept up therein in the following manner :-The piston
and piston rod are formed hollow, and a pipe extends from the former
through the latter to the front end, where it is provided with a vertical
branch terminating in a small receptacle. When the piston rod arrives
at the end of its in stroke the side of the receptacle strikes against the
stem of a small valve in the water jacket of the cylinder, and the valve
being thus opened water passes from the water jacket into the pipe,
along which it flows into the hollow piston, passing thence through the
passage in the piston rod, surrounding the pipe therein, and -escaping
through an opening in the front end of the piston rod.
Although in the above description the engine has been assumed to be
in a horizontal position, yet it can with equal advantage be arranged in a
vertical or inclined position.
It is preferred, for the sake of compactness and convenience of the
parts, to place the engine shaft at the back end of the cylinder, with
the connecting rods extending from the cross head of the piston rod
along the sides of the cylinder to crank pins on fly wheels at each end of
the engine shaft.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Charles Denton Abel in the Great Seal Patent
Office on the 7th July 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES
DENTON ABEL, of No. 20, Southampton Buildings, Chancery Lane, in
the County of Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Eighth day of January, in the year
of our Lord One thousand eight hundred and seventy-five, in the thirty-
eighth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said Charles Denton Abel, Her special license
that I, the said Charles Denton Abel, my executors, administrators,
and assigns, or such others as I, the said Charles Denton Abel, my
executors, administrators, and assigns, should at any time agree with,
and no others, from time to time and at all times thereafter during the
term therein expressed, should and lawfully might make, usc, exercise,
and vend, within the United Kingdom of Great Britain and Ireland,
the Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN
MOTOR ENGINES WORKED BY GAS OF COMBUSTIBLE VAPOUR AND Ara," a com-
munication to me from abroad by Gottlieb Wilhelm Daimler, of
Muelheim on the Rhine, in the German Empire, Engineer, upon
the condition (amongst others) that I, the said Charles Denton
Abel, my executors or administrators, by an instrument in writing
under my, or their, or one of their hands and seals, should particularly
describe and ascertain the nature of the said Invention, and in what
manner the same was to be performed, and cause the same to be filed in
the Great Seal Patent Office within six calendar months next and
immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Charles Denton Abel, do hereby
declare the nature of the said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and
by the following statement thereof, reference being had to the accom-
panying Sheets of Drawings, and to the figures and letters marked
thereon, that is to say:-
This Invention relates to that class of engines wherein by the
explosion of a mixture of combustible gas or hydrocarbon vapour and

page_text: air inside a cylinder a partial vacuum is produced therein, causing a
working piston to be propelled by atmospheric pressure.
According to the present improvements a water jacketted cylinder
open to the atmosphere at both ends contains, firstly, a working piston
connected by a piston rod, cross head, and connecting rod to an engine
shaft having a fly wheel; and secondly, two other pistons, one on each
side of the said working piston. These latter pistons are loose in the
cylinder, and are constructed very light and operate in the following
manner: Assuming the working piston to be at the end of its back
stroke, resting closely against the back loose piston, and with a space
intervening between it and the front loose piston, into which space an
explosive mixture of air and gas or petroleum vapour has been drawn
from an inlet valve, then on the ignition of the explosive mixturo
the front loose piston will be propelled rapidly to the front end of
the cylinder, where it is retained by a contrivance to be presently
described.
The gaseous products of the explosion being cooled by their expansion
and by the cold water jacket of the cylinder a partial vacuum will be
produced in the cylinder whereby the working piston, and with it the
back loose piston, will be caused by atmospheric pressure to travel
together towards the front end of the cylinder. Passing through the
working piston is a rod capable of sliding to and fro so as to project a
certain distance on the one side or the other side of the working piston.
As the working piston approaches the front end of the cylinder the said
rod, in coming in contact with the front loose piston, and being also in
contact with the back loose piston, arrests the motion of the latter,
while the working piston continues its motion to the end of its stroke;
a space is thus formed between the working piston and the back loose
piston, into which a fresh charge of gas and air is drawn. As the same
time the working piston in approaching the front loose piston forces out
the condensed products of combustion contained between them through
an escape valve in the side of the cylinder. When the working piston
has arrived at the end of its forward stroke, being then situated close
against the front loose piston which it has also moved so as to release it
from its fixed position, as will be hereafter described, the charge of gas
and air between it and the back loose piston is ignited, whereby the back
loose piston is propelled to the back end of the cylinder, and the working
piston, together with the front loose piston, are caused to perform their

page_text: back stroke under atmospheric pressure as before described. Thus it
will be seen that this improved engine is double acting, and the
reciprocating motion of the working piston may either be utilised
directly where reciprocating motion is required, such as in pumping
engines and the like, or it may be converted into rotary motion by,
connecting the piston rod to a crank on an engine shaft.
I will now proceed to more particularly describe the construction and
operation of this improved engine, referring to the accompanying
Drawings, in which Fig. 1 shews a longitudinal section of the engine,
Fig. 2 shews a sectional plan, Fig. 3 shews a transverse section on line
X, X, of Fig. 1, and Figs. 4 to 7 shew to, an enlarged scale details
hereafter to be referred to.
The engine as represented on the Drawings is supposed to be hori-
zontal; it may however be arranged in an inclined or vertical position.
The cylinder A, provided with a cold water jacket A', is open at both
ends to the atmosphere, and it is at each end somewhat conically
enlarged, as indicated at A", A". B is the working piston connected by
a piston rod B', cross head C, and connecting rods D, to crank pins on
the fly wheels E', E', on the engine shaft E. The piston and piston rod
are hollow, and cold water is made to circulate through them by means
which will be hereafter described. On each side of the piston B is a
loose piston F, F', the piston rod B' being made to work through packing
f in the front piston F. These loose pistons are of very light con
struction, consisting firstly of a cylindrical part f¹, which carries a
broad ring of leather or other suitable packing material f³ secured at its
middle by a metal ring f³, so that pressure on either side of the piston
tends to force the flexible ring against the cylinder like a cup leather,
preventing leakage past the piston. The piston consists further of a
coned part f, upon which is fitted a loose conical ring f³ formed in
segments that are held together by a small ring ƒ fitting into grooves
in the segments. This segment ring is connected to springs f passing
through slots in the part f', which springs tend to keep the segment
ring at the smallest diameter of the part f', in which case, the segments
being retracted the piston can move freely in the cylinder. When,
however, the loose piston is propelled by the explosion of the gas and air
into the conical enlargement A' of the cylinder, and is there suddenly
arrested by the counterpressure of the atmosphere, the conical segment
ring f³, in continuing its forward motion by virtue of its momentum,
"

page_text: slides up the conical surface f*, and being thus expanded wedges itself
tightly between this conical surface of the cylinder as indicated in dotted
lines at Fig. 2, and thus the piston F is held securely in this position.
The pistons F, F', are open at their outer sides, but at their inner sides
they are closed air-tight by means of a curved plate 18, strengthened by
stays P, and formed to the same curvature as the working piston B so
as to fit closely thereto. Passing air-tight through the piston B is a
sliding rod G (Fig. 1) with heads at its ends. This rod, in coming in
contact with either of the loose pistons when it bears against the other
keeps the former at a certain distance from the piston B, thus causing a
charge of gas and air to be drawn into the space between them at the
end of every stroke, as will be presently described.
The cylinder A has two ports H, H', for the admission of a charge of
gas and air at the end of each stroke, such admission being regulated by
valves I, I', constructed and operating as will be hereafter described, and
worked by means of cams or tappets E³, E³, on the engine shaft E acting
on rods K, K', connected to the valves.
The mode in which the engine operates is as follows:-Assuming the
working piston B to be at the end of its back stroke resting closely
against the loose piston F' and with a space intervening between it and
the second loose piston F, as shewn in Figs. 1 and 2, and assuming further
that a charge of gas and air has been admitted into this space through
the valve I' and is then ignited, then upon the explosion taking place
the piston F is rapidly propelled to the front end of the cylinder, into
the position indicated by dotted lines in Fig. 2.
The gaseous products of the explosion being rapidly cooled by their
expansion and by the cooling action of the water jacket A' and of the
cooled piston and piston rod a partial vacuum is formed in the cylinder,
in consequence whereof the motion of the piston F is arrested as it
approaches the front end of the cylinder by the counteracting pressure
of the external atmosphere, but the segment ring ƒ³ being carried still
onwards by its own momentum wedges the piston F tight in this front
position, as already explained, the conicity of the part A² of the cylinder
holding it firmly there by absolute counterpressure, and not merely by
frictional contact. In consequence of the reduction of pressure in the
cylinder the working piston B and the hinder loose piston F' are now
caused by the external atmospheric pressure to travel together towards

page_text: the front of the cylinder, the packing of the piston F'acting in aid of
the piston B to prevent leakage of air into the cylinder. When the
piston B approaches the end of its forward stroke the rod G projecting
therefrom comes in contact with the piston F and arrests the motion of
the piston F', so that as the working piston B continues to advance a
space is formed between its back surface and the piston F', and the
valve I being now opened a charge of gas and air is drawn into this
space. At the same time the piston B in approaching the piston F
forces out the condensed products of combustion contained between
them through an escape passage L (Figs. 1 and 2) provided with a
check valve L'. The force of the explosion is so regulated that the
piston F in its flight is arrested somewhat short of the full stroke of the
piston B, so that when this latter comes in contact with the former it
pushes it a little farther forward up to the extreme end of the cylinder
to a position corresponding at the front end to that in which the
piston F is shewn at the back end. The segment ring f being thus
released from its jammed position is caused by the springs f' to move
into the retracted position shewn in the piston F', so that the piston F is
now loose in the cylinder. The explosive charge in the space between
the pistons B and F' being now ignited the piston F' is propelled to the
back end of the cylinder where its flight is arrested as before described
with reference to F, and the pistons B and F then perform their back
stroke, the piston F being arrested by the rod G near the end of its
stroke in order to draw in a fresh charge of explosive mixture, and so
on. At the extreme end of each stroke the piston B presses the
pistons F, F¹, slightly against annular buffer plates M, M', held in a
yielding manner against the ends of the cylinder by means of bolts
passing through lugs A³ on the cylinder with india-rubber washers M* at
the back. The object of this arrangement is to insure that all the
products of combustion shall be forced out from between the pistons B
and F, F', and that the latter shall fit closely against the former while
performing their stroke.
Instead of arresting the motion of the loose pistons by the rod G, as
described, this might be effected by means of catches or stops actunted
by the engine shaft (or by the stem of the admission valves) so as to
project through the side of the cylinder at the required time and place
and thus stop the loose piston. As I have before stated the packing of
the loose pistons F, F', operates in aid of the packing of the piston B as

page_text: they follow the latter closely while it performs its stroke. The operation
of the engine may therefore be modified by making the piston B simply
as a disc to work loosely or without packing, in which case each of the
loose pistons acts alternately as the working piston, pressing against B
when caused to perform its stroke by the atmospheric pressure, and thus
imparting motion to the engine shaft through the piston rod B'.
It will be evident that instead of effecting the drawing in and
ignition of the explosive charge when the piston B has arrived at the
end of its stroke, as before described, this might be effected when the
piston has performed only part of its stroke, in which case it would be
propelled to the end of its stroke by the force of the explosion at the same
time that the loose piston is thrown to the other end of the cylinder.
The construction of the valve gear I, I', for admitting the charge of
combustible gas and air into the cylinder, and the arrangement for
igniting the charge is shewn at Figs. 4 and 5, which shew respectively
an enlarged longitudinal section and a transverse section on line Z, Z,
of the valve gear. The valve casing I communicates with the cylinder
port H by a passage i opening into the chamber . In this chamber is
a conical valve fitting against a seat ?, and having a stem ³ of large
diameter passing through a second chamber in the valve casing and
out through the end thereof. The stem has a central passage
'
passing right through it which serves for the admission of atmospheric
air, and round this are formed a number of small passages i commu-
nicating at the one end with an annular passage which is connected
the other end the
by a nozzle to a flexible gas supply pipe; at
passages i open into the face of the conical valve . Thus when the
valve is away from its seat, as shewn in Fig. 4, air and gas can pass
through the passages is and i' into the chamber i, whence the explosive
mixture passes into the cylinder; but when the valve is closed the gas
and air supplies are simultaneously cut off.
The valve is actuated in the following manner:-It is connected by
bars with a piece i" working air tight in the front end of the casing I,
to which piece is attached the rod K that receives motion from the
cam E on the engine shaft. Upon this rod is an adjustable nut k and
plate k', against which presses a spiral spring that abuts against a
shoulder on the valve casing. Thus the rod K being acted upon by the
cam E³ pushes the valve open at the proper time for the admission of air

page_text: and gas, and on the nose of the cam leaving the end of the rod the
spring acting against the plate k' pushes the rod back and so closes
the valve with a rapid motion which can be regulated by screwing the
nut more or less on the rod K so as to regulate the pressure of the
spring. In the bottom of the chamber i' is a gas jet i" kept constantly
burning, which is supplied with air through the holes i¹³ in the casing,
while a chimney is provided at the top of the chamber i to promote a
draught for the flame which plays round the stem i³ of the valve. The
valve is formed with a cylindrical part, which when it is open fits into
a circular opening is between the chambers i¹ and i', and thus shuts off
the communication between these chambers through such opening. As
the valve closes it uncovers this opening and at the same time a disc¿¹
formed on the stem ³ advancing rapidly conveys a portion of the flame
that is playing round the stem in the chamber i through the opening *"*
into the chamber i', and then closes the communication between i' and i*
again by fitting with a bevilled rim against the bevilled face i". At the
same time the flame carried into passes thence through the opening i
and port H into the cylinder and ignites the explosive charge therein.
The power of the engine is regulated by a governor in such a manner
that should the speed of the engine be too great the supply of com-
bustible gas is entirely cut off, and the working piston consequently
performs its strokes without any explosion of gas and air taking place,
until by the reduction of the speed the gas supply is again fully opened,
so that the proper proportions of combustible gas and air and the
quantity of the mixture required for each explosive charge in order to
produce the best results having been once determined, these proportions
and quantity are not in any way varied for increasing or decreasing the
the power of the engine. The arrangement for this purpose will be
understood on reference to Figs. 6 and 7, which shew respectively an
enlarged transverse section and part longitudinal section of the engine
shaft with the regulating mechanism. O, O', is the supply pipe for com-
bustible gas, which is connected by flexible tubes to the nozzles i³ on the
admission valve as before described. The gas passes from O into O'on its
way to the engine as indicated by the arrow. Over the mouth of the
pipe O' is a valve P attached to a spindle P' passing through a stuffing
box O' on the pipe, and carried externally by a thin steel plate Q' fitting
into a neck on the spindle, as shewn, and connected to the arms of the
governor balls Q. These are carried by brackets projecting from a

page_text: sleeve Q³, which rotates upon the cylindrical gland O³, carrying with it
the governor balls, such rotation being effected by a bevil pinion Q³ fixed
to the sleeve Q³, and in gear with the bevil wheel R fixed on the engine
shaft E. The spindle P' (which does not revolve with the governor)
passes through the pinion and extends upwards, having a head P'. This
head projects laterally, as shewn, so as to pass over or under two
projections R', R', formed on the face of the wheel R. The head P³ is
formed with a feather edge presented towards a feather edge formed on
the projections R', and these are formed with inclines as shewn; while
the engine is running at its normal speed, the governor being adjusted
so as to hold the head of the spindle at such a height that its feather
edge is just above that of the projections R'. These in rotating pass
underneath the head, and thus keep the valve P raised full open
during the intervals when a charge of gas and air has to be drawn
into the cylinder. When however the speed of the engine is slightly
increased the governor causes the spindle P' to be slightly depressed, so
that the feather edge of P is brought slightly below the feather edge
of R', and consequently the inclined surface of the latter in passing
over the head P* presses down the spindle P', and consequently closes
the valve P, thus entirely cutting off the supply of gas during the
time that the admission valve of the engine is open. Thus as the
governor serves only to bring into action the mechanism for cutting
off the gas supply a very slight increase of speed beyond that
required at once causes the gas supply to be entirely cut off, as above
described.
In the gas supply pipe O is a flap valve S, which is kept open by a
weight S', that can be screwed more or less through the valve, and thus by
shifting its centre of gravity regulate the extent to which it is kept open.
The object of this valve is to prevent more than the regulated quantity
of gas for each charge from entering the cylinder, as should by any
chance the loose piston in following the working piston stick in the
cylinder before completing its stroke, and thus cause an increased suction
to take place in the cylinder by reason of the greater space that would
be formed between the loose piston and the working piston, then such
increased suction, in drawing the gas from the right-hand side of the
valve S quicker than it could flow past the valve, would cause the valve
to be more or less closed by the pressure behind it, so as to throttle
the gas supply.

page_text: As before stated it is proposed to work the engine either by ordinary
coal gas or by hydrocarbon or petroleum vapour.
If coal gas is
employed it enters the pipe O through the branch 03, shewn in dotted
lines at Fig. 1, leading from any convenient point of supply, and passes
thence through the pipe O', O', passing along the cylinder, either inside
the water jacket thereof, as shewn, or outside of the same, and provided
with two branches, by which it is connected by means of lengths of
flexible tubing Oʻ, O', to the nozzles on the admission valves I, I'. If
the engine is to be worked by petroleum vapour the liquid petroleum is
introduced in a small stream into the funnel-mouthed opening T' of a
pipe T that passes along the cylinder inside the water jacket, at the end
of which it communicates with the pipe O, as shewn at Fig. 1. The
small stream of liquid petroleum in flowing along the pipe T is converted
into vapour by the heat of the water in the water jacket, and this vapour
mixing with a certain quantity of air that also enters the funnel-
mouth T' flows through the pipes O and O' to the admission valves I, I¹.
The volatilisation of the whole of the petroleum is still further insured
by the additional heating it obtains on its passage through the pipe O'
inside the water jacket, and should any particles escape perfect volatili-
sation or become recondensed on their passage through the flexible
pipes 0, 0, into the valves I, I', they are vaporised on their passage
along the channels by the heat of the flame i" playing round the
valve stem i³. The flame i" may in this case be supplied either from a
special petroleum lamp or from ordinary coal gas.
Although a certain amount of air is mixed with the petroleum vapour,
as described, yet a further air supply is required for the explosive chargo,
and as in this case it is necessary to heat such air supply before it mixes
with the petroleum vapour I introduce it through an opening U' in the
cylinder jacket (Fig. 3) into a pipe U inside the jacket, where it becomes
heated, and whence it is led through flexible tubes U³ to the end of the
passages of the admission valves. Here the air also becomes further
heated by the flame i". By causing the air and gas to pass through
pipes in the water jacket so as to take up heat from the water, as,
described, there results a saving of heat, which would otherwise be lost,
and a reduction of the quantity of cold water required in consequence
of the refrigerating action produced by the evaporation of the petroleum
upon the water. The volatilisation of the liquid petroleum might also
be effected by conducting it through small pipes inside a chamber, into

page_text: which the hot products of combustion are made to issue from the
passages L, or by causing the products of combustion to pass over the
exterior of and through pipes in a chamber containing porous material
saturated with petroleum.
For effecting the circulation of water through the working piston
and piston rod, as before mentioned, the following arrangement is
employed:-Inside the hollow piston rod is a pipe V extending into the
piston, where it is provided with a branch V₁ (Fig. 1) leading into the
body of the piston. At the front end of the piston rod this pipe carries
an upright branch V* terminating in a small receptacle V³. As the
piston arrives at the end of its back stroke the stem W of a small
valve W closing an opening in the end of the water jacket A' comes in
contact with the side ef the receptacle V³, whereby the valve is forced
from its seat, thus allowing a certain quantity of water to flow from the
water jacket into the receptacle, whence it passes down the branch V³,
pipe V, and branch V' into the piston. At the same time water escapes
from the upper part of the piston through the pipe V* into the space in
the hollow piston rod surrounding the pipe V, flowing to the front end of
the piston rod, and escaping through the outlet V³ into a trough that
conducts it away. When the receptacle V³ moves away from the
valve W on the piston B beginning its forward stroke the valve is
closed by means of a spring W. Cold water is supplied to the cylinder
jacket A' through the pipe Y.
Having thus described the nature of this Invention, and in what
manner the same is to be performed, as commmunicated to me by my
foreign correspondent, I claim,-
First. The construction and arrangement of a double-acting gas engine
having a cylinder open at both ends to the atmosphere, with a working
piston, on each side of which is a loose piston so arranged that at the
end of each stroke the one loose piston by the explosion of a charge is
propelled to the end of the cylinder without doing work, and is held
there while the gaseous products of combustion contract by cooling, and
the working piston together with the second loose piston is caused by
atmospheric pressure to perform its stroke, substantially as herein
described.
Second. In a double-acting gas engine of the kind above referred to

page_text: combustion on one side of the working piston, and the drawing in of
an explosive charge on the other side of the piston by means of a
sliding rod maintaining a space between the loose pistons, substantially,
as herein described.
Third. In a gas engine of the kind above referred to the method of
retaining the loose piston at the end of its out stroke by a coned part of
the cylinder surface, substantially as herein described.
Fourth. In gas engines of the kind referred to the use of the loose
piston F, with cylindrical part f' fitting with packing against the
cylinder, and coned part f³, with conical segment ring f³ controlled by
springs f, and operating in combination with the coned ends A' of the
cylinder A, substantially as herein described.
Fifth. The method of releasing the loose piston from the coned end of
the cylinder by the pressure on it of the working piston, substantially, as
herein described.
Sixth. In gas engines of the kind referred to the combined operation
of the working piston and the loose piston in such a manner that the
latter, which is packed, presses during its in stroke on the former, thus
permitting the packing of the working piston to be dispensed with.
Seventh. The use in gas engines of the kind above referred to of
yielding annular buffer plates M operating in combination with the
pistons F for effecting a close contact between them and the working
piston, substantially as herein described.
Eighth. The method of regulating the power of gas or petroleum
engines by entirely cutting off the supply of combustible gas or
vapour when the engine is running above its normal speed, while the
working piston remains continuously in motion, substantially as herein
described.
Ninth. The method of controlling the supply of combustible gas or
vapour to gas or petroleum engines by means of a governor operating in
such a manner that the gas supply is either fully open or entirely closed,
whereby a uniform quantity of gas for each charge is insured, sub-
stantially as herein described.
Tenth. In apparatus for regulating the supply of combustible gas or
. vanour to as on notmalam
•

page_text: •
stem P' and head P³, operating in combination with the governor Q and
projections R' so that the governor only serves to bring parts into action,
whereby the gas supply is either entirely closed or fully opened, sub-
stally as herein described.
. Eleventh. The use in the gas supply pipe of the throttle valve S, with 5
adjustable weight S', for preventing an increased gas supply to the engine
cylinder consequent upon an increased suction in the same, substantially
as herein described.
"
Twelfth. The use in gas or petroleum engines of the admission valve
apparatus I, with inlets for both gas and air formed in the valve and 1
valve stem itself, and so arranged that by the closing of the valve the
gas and air supply are simultaneously cut off, substantially as herein
described.
Thirteenth. The use in gas or petroleum engines of the admission valve
apparatus I, with valve i³, air and gas passages i³, i, i, chambers i¹, i*,
aperture i¹³, disc i¹, and gas jet is, arranged and operating by means of
the rod K and spring ³, substantially as herein described.
Fourteenth. In admission valve apparatus to gas or petroleum engines
the gas jet ¿¹ burning in the chamber i*, with air holes i¹³, and chimney ¿¹,
the said gas jet being made to ignite the charge in the engine cylinder by :
causing a portion of the flame to be conveyed by means of the disc g¹º
into the valve chamber, substantially as herein described.
Fifteenth. In admission valves to engines worked by petroleum
vapour, the method of heating the petroleum vapour and the air on their
passage through the valve by means of the flame that serves to ignite:
the charge, substantially as described..
Sixteenth. In gas or petroleum vapour engines the method of utilising
a portion of the heat of the water in the water jacket of the cylinder for
heating the gas or petroleum vapour and air before passing into the
cylinder, substantially as herein described..
Seventeenth. In petroleum vapour engines the method of producing
the petroleum vapour by causing the liquid petroleum to flow through
pipes inside the water jacket, whereby it is volatilised, while at the samo
time the water is refrigerated by the cold produced by such evaporation
of the petroleum, substantially as herein described!
3
1

page_text: Eighteenth. The arrangement of the hollow piston B and piston
rod B' supplied with water from the water jacket of the cylinder by
the valve W, receptacle V³, and pipes V, V, V', substantially as herein
described.
In witness whereof, I, the said Charles Denton Abel, have hereunto
set my hand and seal, this Third day of July, in the year of our
Lord One thousand eight hundred and seventy-five.
CHA³. D. ABEL. (L.S.)