IMPROVEMENTS IN GAS MOTOR ENGINES."
Year: 1874

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 GAS MOTOR ENGINES."
-A com-
munication from abroad by Gottlieb Wilhelm Daimler, of Muelheim

page_text: The engine described in the said Specifications operated in the
following manner :-A piston was raised in a cylinder a little distance
drawing in through the ports of a slide a charge of combustible gas and
air at atmospheric pressure in suitable mixture for ignition. A flame
being the drawn in ignited the gaseous mixture which by its expansion
propelled the piston along the cylinder. The cylinder being kept cool
by a water jacket the pressure of the products of combustion within the
cylinder was rapidly reduced, and the cylinder being open at top the
piston was propelled backwards by the superior pressure of the external
atmosphere, the products of combustion being finally expelled by the
piston as it approached the extreme of its in stroke. The piston rod was
toothed as a rack and geared with a wheel mounted on the engine shaft
which was provided with a heavy fly wheel. The wheel geared to the
piston rod was mounted on the engine shaft with a clutch in such
manner that it could turn freely on the shaft in the one direction when
the piston was making its out stroke, but that when the piston was
making its in stroke the wheel caused the shaft to revolve with it. This
shaft or a shaft connected with it had on it cams or eccentrics for
moving the piston through a portion of its out stroke to draw in the
gaseous charge, and also for moving the slide so as to admit the gascous 2
mixture and the igniting flame to the cylinder, and to permit the
products of combustion to escape therefrom.
In the improved engine to which the present Invention relates the
principle of action is substantially the same as that set forth above, but
the working of the piston and slide from the main shaft is effected in a
more simple and efficient manner than formerly; the slide is arranged to
operate upon a single passage for inlet to and outlet from the cylinder,
and the action of the engine is regulated by a governor so as to
economize expenditure of gas when the velocity of the shaft is sufficient
for the work of the engine. For this purpose a crank is mounted loosely a
on the main shaft of the engine, having on it a spring pawl which can
engage with the teeth of a ratchet wheel fixed on the engine shaft, or be
disengaged therefrom as will presently be described. When the pawl is
engaged the crank revolves with the shaft, but when the pawl is
disengaged the crank remains at rest. From this crank there are 3
two rods, one connected to the slide which is worked when the
crank revolves with the shaft, and the other connected by a slotted
hole to a lever fixed on a rocking shaft which has two arms. One of

page_text: these arms is pressed upwards by a spring, and when it is so pressed
upwards it comes in the way of the pawl on the crank, and in
disengaging it from the ratchet wheel brings the crank to rest. The
other arm supports a forked rod presenting its fork to a pin pro-
jecting from the piston rod. When the piston is down this pin
resting in the fork of the rod prevents it from rising, and thus prevents
the pawl on the crank from being disengaged. The crank in its
revolution with the shaft while it moves the slide moves also the rocking
shaft and its arms, and the last described arm with its forked rod being
thus raised pushes up the pistion so as to draw into the cylinder the
gaseous charge and the igniting flame. The expansion caused by the
combustion of the charge propels the piston upwards and the pin is thus
raised out of the fork of the rod which is then free to rise in obedience
to the spring, whereupon the other arm of the rocking shaft is brought
in the way of the pawl and disengages it from the ratchet wheel. The
crank now remains at rest and the slide is stationary until the piston on
its descent brings the pin into the fork of the rod, whereby the arms of
the rocking shaft are pressed down, the pawl is set free and engages
again with the ratchet wheel, and the action is repeated. A governor
driven by bevil gear from the main shaft works a lever, one end of which
when the governor balls are expanded comes in the way of a projection
on the spring pawl and prevents it from engaging with the ratchet
wheel. But when the governor balls collapse the end of the lever is
moved out of the way of the pawl, which is then free to engage with the
ratchet wheel as described above. Thus when the engine shaft is
revolving with a speed so great as to prevent the pawl from engaging
the slide and piston remain quiescent, and there is no expenditure of
gas. But when the speed of the shaft is so far reduced as to permit the
pawl to engage, the slide and piston are moved so as to charge the
cylinder and ignite the charge, and the return stroke of the piston gives
additional motive power to the revolving shaft.
The slide worked as above described is made with ports and passages,
and the slide face and cover are made with corresponding ports and
passage for the ingress of air and gas and of the igniting flame, and for
the egress of the products of combustion through one and the same
passage communicating with the cylinder. Such ports and passages
are arranged as follows:-The slide face has a passage for the ingress of
air and a port connected to a pipe for the supply of combustible gas,

page_text: and the slide has two recesses of which one serves to put the said air
passage in communication with the port or passage of the slide face
leading into the cylinder, while the other serves to establish a com-
munication between the said gas port and a second gas port in the
slide face through which the gas is conducted into the air recess of the
slide through a number of small holes, so as to mix thoroughly with
the air and pass with it into the cylinder.
Besides the above mentioned gas supply pipe there are two other gas
pipes, one of which communicates with a hole in the slide face, while
the other communicates with a gas jet which is kept burning in a hole
in the slide; when the charge of gas and air has been drawn into
the cylinder the slide is moved so as to cause a passage in the lower part
to communicate with the said gas hole in the slide face and with the
atmosphere, whereby the said passage is filled with gas and air;
this charge is ignited by the before-mentioned gas flame, and on the
continued upward motion of the slide the said passage with its ignited
charge is made to communicate with the passage leading into the
cylinder, and thus the charge in the latter is ignited. By the sudden
expansion of the charge caused by its ignition the piston is propelled
rapidly upwards, after which, as the products of combustion contract, the
piston descends; as it approaches the end of its down stroke the slide
is moved so as to present a passage for the egress of the products of
combustion. The passage of egress may be controlled by an adjustable
valve so as to moderate the descent of the piston during the last portion
of its stroke.
The slide cover is kept against the slide by means of a spring arm
fixed to the stand of the engine and bearing against the slide cover by
means of a set screw, whereby its pressure can be regulated.
The engine shaft is mounted on bearings on brackets projecting from a
ring bolted on the top of the cylinder, the brackets and shaft being arranged
in such position that the piston can be drawn out of the cylinder without
removing them. The toothed ring and clutch apparatus whereby only
the downward motion of the piston and piston rod is communicated to the
engine shaft, are similar in action to the apparatus described in the before-
mentioned Specifications, but they are of the following modified con-
struction: The toothed ring is in this case made of wrought iron, the
hollows between its teeth not being cut out to the outer edge, thus

page_text: leaving a shroud for strengthening the teeth. This toothed ring is
secured to a disc on a cast iron nave loose on the engine shaft, the disc
having an annular lip which overlaps a grummet on the inner face of the
toothed ring on to which it is shrunk, so as to strengthen the toothed
ring. A ring plate is screwed against the outer face of the toothed ring
to keep in the wedges and rollers of the clutch apparatus, and to allow
these to be readily removed for inspection or repair. The loose nave
of the toothed ring is made with a boss projecting into a recess in the
fixed nave of the clutch apparatus, and in this recess is formed a circular
hollow into which any of the lubricating oil escaping from the loose
nave drops, and whence it flows away through a lateral passage or pipe
in the fixed nave. By this means the oil is prevented from flowing into
the clutch apparatus, the action of which would be impaired thereby.
The toothed rack on the piston rod which gears into the before-
mentioned toothed ring is grooved at the back and works on a dovetail
guide formed on a bracket which is secured to the cylinder cover, and
under this bracket is fixed an annular buffer of caoutchouc against which
the piston can strike in case of its too violent propulsion.
The lower part of the cylinder is spread out to form a stand for the
engine, and on this extended part is fixed a water jacket which is carried
up the whole height of the cylinder, instead of extending only partially
up the cylinder as described in the before-mentioned Specifications. By
this means a volume of water is kept in contact with the cylinder for
cooling the same, sufficient to render a continuous circulation of water
unnecessary. The jacket extends under the cylinder, and below it is a
space to which free access is given for circulation of air.
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 11th June 1874.
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.

page_text: our Lord One thousand eight hundred and seventy-four, in the thirty-
seventh 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, adminis-
trators, 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, use, exercise,
and vend, within the United Kingdom of Great Britain and Ireland,
the Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS
IN GAS MOTOR ENGINES," a communication to him from abroad by Gottlieb
Wilhelm Daimler, of Muelheim on the Rhine, in the German Empire,
Civil 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 Drawings and to the figures and letters marked thereon, that
is to say :-
This Invention relates to improvements in gas motor engines of the
kind described in the Specifications of Letters Patent granted to me
on the 12th February 1866, No. 434, and on the 3rd August 1867,
No. 2245, being communications to me from E. Langen and N. A. Otto.
The engine described in the said Specifications operated in the following
manner: A piston was raised in a cylinder a little distance, drawing
in through the ports of a slide a charge of combustible gas and air at
atmospheric pressure in suitable mixture for ignition. A flame being
then drawn in ignited the gaseous mixture, which by its expansion
propelled the piston along the cylinder. The cylinder being kept cool
by a water jacket the pressure of the products of combustion within
the cylinder was rapidly reduced, and the cylinder being open at top
the piston was propelled backwards by the superior pressure of the

page_text: external atmosphere; the products of combustion being finally expelled
by the piston as it approached the extreme of its in stroke. This piston
rod was toothed as a rack and geared with a wheel mounted on the
engine shaft, which was provided with a heavy fly wheel. The wheel
geared to the piston rod was mounted on the engine shaft with a clutch
in such manner that it could turn freely on the shaft in the one direction
when the piston was making its out stroke; but that when the piston
was making its in stroke the wheel caused the shaft to revolve with it.
This shaft, or a shaft connected with it, had on it cams or eccentrics for
moving the piston through a portion of its out stroke to draw in the
gaseous charge; and also for moving the slide, so as to admit the
gaseous mixture and the igniting flame to the cylinder, and to permit
the products of combustion to escape therefrom.
In the improved engine, to which the present Invention relates, the
principle of action is substantially the same as that set forth above, but
the working of the piston and slide from the main shaft is effected in
a more simple and efficient manner than formerly; the slide is arranged
to operate upon a single passage for inlet to and outlet from the
cylinder, and the action of the engine is regulated by a governor, so as
to economise expenditure of gas when the velocity of the shaft is
sufficient for the work of the engine.
The nature of these improvements will be understood on reference to
the accompanying Drawings, and to the figures and letters marked
thereon.
Fig. 1 represents a front view, partly in section, of the improved
engine; Fig. 2 is a plan, partly in section; Fig. 3 is a vertical
section on line A, B, C, D, of Fig. 1; and Fig. 4 is a front view of the
slide; and Fig. 5 is a front view of the face on which the slide
works.
a is the engine shaft mounted in bearings on brackets E projecting
from a ring E', which is bolted on the cylinder top; the opening in
the ring E' being sufficiently large to admit of the piston f being taken
out of the cylinder without dismounting the shaft a or its bearings.
On the shaft a is mounted the toothed ring a¹ with its clutch u, similar
in action to that described in the Specification above referred to, the
toothed ring a being always in gear with the rack f¹ which constitutes the
piston rod, but being so clutched to the shaft a that it turns freely and

page_text: independently of the shaft in the one direction when the piston ascends,
but that in the other direction when the piston is descending it is
engaged with the shaft. This, as explained in the former Specification
referred to, is effected by mounting the nave a², to which the toothed
ring a¹ is attached, loose upon the shaft, and arranging within the
toothed ring a¹, and between it and the nave u¹ which is fixed on the
shaft, curved wedge pieces and rollers u, which give a bite by friction
when the toothed ring turns in the one direction, but relieve themselves
when it turns in the other direction.
Although this kind of clutch is substantially the same in principle
and action as that formerly described, the present Invention embodies
certain modifications in the construction of the parts which will now
be described. The toothed ring a¹ is preferably made of wrought iron,
but the hollows between its teeth are not cut out to the outer edge, a
portion of the metal being left at the end of each hollow, as shewn,
to act as a shroud for the teeth, giving them greater strength. The
nave a², of cast iron, is made with a lip to overlap a grummet on the
other face of the toothed ring, and is shrunk on, so as to strengthen it
against the bursting strain of the wedge clutch within it. A ring
plate u³ is screwed on the outer face of the toothed ring to keep the
wedge, clutches, and rollers from shifting endways, and to enable these
to be readily taken out for inspection or repair. The loose nave a² is
made with a boss as projecting into a recess within the fixed nave u³,
which is made with a bulge u³, so that the oil employed to lubricate
the loose nave and escaping into the cavity within the fixed nave is
kept by the bulge us from flowing outwards into the clutch, and is
allowed to issue by a small pipe u'. The rack f¹ is grooved at the
back and works on a dovetail guide formed on the bracket v, which is
secured on the top of the cylinder, and thus the rack is prevented
from getting too deeply or too little in gear with the wheel a', and is
always truly guided in a direction parallel to the axis of the cylinder.
Under the bracket v is fixed an annular buffer F of caoutchouc, against
which the piston can strike in case of its two violent propulsion
upwards.
The lower part of the cylinder få is spread out to form a stand f³ for
the engine, and on this extended part is bolted the water jacket w which
is carried up the whole height of the cylinder instead of extending only
partially up the cylinder, as described in the former Specification

page_text: referred to. By this means a volume of water is kept in contact with
the cylinder for cooling the same, sufficient to render a continuous
circulation of water unnecessary. The jacket extends under the cylinder,
and below it is a space to which free access is given for circulation of
air. The cylinder bottom f' rests on a shoulder in the cylinder, and
below the cylinder is a cover f³ which forms the bottom of the water
casing; both the covers f' and ƒ³ are secured in their places by one
central bolt f. From the bottom of the cylinder a passage x extends to
the slide facing which is placed somewhat obliquely, as shewn in Fig. 1,
so as to bring the axis of the slide in line with that of the shaft a from
which it is worked. The slide cover h is held in place by a strong
spring provided with a set screw h¹ which bears against the cover,
with a pressure that can be adjusted by screwing it more or less forward.
The slide face y has through it a passage y' for admission of air, and has
in it a hole y¹ to which is connected the pipe y² for the supply of combus-
tible gas. The slide d has in its upper part two recesses d', d³, of which
the one d¹ faces the opening y', and the other d² faces the hole y¹ from
the gas supply y, and in certain positions of the slide puts this hole in
communication with another hole y' in the facing, from which hole there
is a passage having a number of small apertures y³ opening towards the
recess d¹ of the slide. When the slide is moved down so as to bring this
recess to face the passage x, and the piston is caused to rise somewhat for
drawing in the charge of gas and air preparatory to performing its
stroke, air enters by the passage y* and recess d', and gas enters by y¹, d²,
and y', and the small holes y³, also to the recess d³, and the air and gas
mingling enter the cylinder by the passage x. Besides the gas supply
pipe y³ there are two other gas pipes y³ and h², the one communicating
with a hole y in the slide facing, and the other with a jet h³ which
is kept burning immediately outside a hole in the slide cover h.
In the slide & there is a hole d³ and recesses communicating with it
which when the slide is about the middle of its stroke, as shewn in
Fig. 3, become charged with gas from yº and air entering at the lower
end of d³. This mixture is ignited by the flame h³, and as the slide
ascends, cutting off the supply of gas and air to the cylinder, the inflamed
gas in d³ is brought into communication with the gaseous mixture in
the passage x, and the contents of the cylinder are thereby ignited, their
expansion propelling the piston upwards. A recessed hole d' in the
slide is made wide enough to extend over the passage x, and also over a

page_text: passage y' at the side thereof in the slide facing; this latter passage
communicates with an eduction pipe, as shewn in Fig. 5, which may be
provided with a screw valve for moderating the issue of the products of
combustion. When the slide descends again to or near its middle position,
as shewn in Fig. 3, the products of combustion issue from the cylinder
by the passage x, the holes d' and y', and the eduction pipe and valve.
A recess ' in the slide cover allows a portion of the gas and air to
pass from the recess & through the passage d' into the cylinder when
the slide is in such a position that both d¹ and d' are over the recess h*,
whereby an increased area of passage for the gas and air into the
cylinder is afforded, and the passage d' is cleared of the products of
combustion from the previous explosion.
Fig. 6 shews the slide in position for the supply of the gaseous
mixture to the cylinder, and Fig. 7 shews it in position for the ignition
of the charge in the cylinder.
The working of the slide d so as to operate in the manner described
in due accord with the movement of the piston is effected by mechanism
which will now be described, which mechanism also imparts to the
piston that portion of its upward movement which is necessary for
drawing the gaseous charge into the cylinder, and is so arranged as to a
be under the control of a governor.
The end of the rotating shaft a is bored up, and a spindle 6 is fitted
therein so that it may revolve freely. On the end of the spindle 6 is a
crank 6', the pin c of which is connected by a rod e to the slide d. The
crank b¹ also carries a spring pawl p engaging with the teeth of a
ratchet wheel o fixed on the shaft a. When the pawl is engaged with
any of the ratchet teeth the shaft revolving in the direction of the
arrow (Fig. 1) drives the crank 6, but when the pawl is disengaged, as
shewn in Fig. 1, the crank b¹ remains at rest. The head of the rod e is
made with a loop e¹ presenting a slotted hole into which enters a pin on
a rod i jointed to a lever k; this lever is fixed to a rocking shaft / from
which project two arms m and q. The one arm m has jointed to its
end an upright rod n, which at its top presents a fork that receives a
pin fprojecting from the side of the rack piston rod f¹. The other
arm q is pressed upwards by a spring q¹. While the piston is at the ;
lower extreme of its stroke the pin f' on its rod resting on the fork of n
the arms m and 9 are kept down in opposition to the spring q', and the

page_text: pawl p being engaged with the ratchet wheel o the crank 6¹ is caused to
revolve with the shaft a. In its revolution the crank 6' works the slide d
by means of the rod e, and it also works the lever k and rocking shaft /
during part of its motion, raising the arm m and fork of n, and thereby
raising the piston so as to draw the gaseous charge into the cylinder.
During another part of the motion of the crank the arms m and q are
depressed, but not to the full extent, the slot in which the pin of the
rod works permitting the spring q¹ to keep up the arm q in such a
position that as the pawl p is brought round by the rotation of the
crank a tail p¹ projecting from the pawl is caught by the end of the
arm q, and the pawl is thus disengaged from the ratchet wheel o which
goes on revolving while the crank remains at rest; but on the piston
fully descending the pin f' on its rod entering the fork of n pushes
down the arm m, and thereby causes the arm q to be withdrawn from
the tail p¹ of the pawl, whereupon the pawl p is caused by its spring to
engage with the ratchet wheel o, and the crank b¹ is again caused to

page_text: stantially as herein described.
In witness whereof, I, the said Charles Denton Abel, have here-
unto set my hand and seal, this Tenth day of June, in the year
of our Lord One thousand eight hundred and seventy-four.