Improvements in Gas-engines.
Year: 1899

page_text: Date of Application, 14th Mar., 1899-Accepted, 15th Apr., 1899
COMPLETE SPECIFICATION.
Improvements in Gas-engines.
I, LOUIS JOSEPHI HIRT, of Grove Street, Brookline, Massachusetts, United States
of America, Engineer, do hereby declare the nature of this invention and in what
manner the same is to be performed, to be particularly described and ascertained in
and by the following statement:-
1
This invention relates to gas engines and has for its object to provide an engine
which is capable of operating as a constant pressure engine and of being auto-
matically converted into a variable pressure engine by diminution of the pressure of
the gas employed to run the engine. In accordance with this invention, the engine
may be started under a constant pressure and run 'as a constant pressure
engine, gas being admitted and exploded at each stroke of the engine until the
engine is running in the desired or proper manner, and when it is so running, the
supply of gas and air at a reduced pressure may be admitted to the engine cylinder,
and the engine responds to the diminution in the pressure of the gas and
automatically converts itself into a variable pressure engine in which the gas is
exploded once for every two complete reciprocations of the piston.
In the present instance, I have embodied my invention in a double acting engine
of the well known Corliss type, in order that the operation of the engine may be
clearly shown and easily understood, but I do not desire to limit my invention to
this particular type of engine as it can be embodied in other well known forms of
engines.
In accordance with this invention, the admission and exhaust valves for the
engine are adapted to be operated at each stroke of the piston when the latter is
running under a constant pressure, but are controlled automatically as will be
described by the pressure of the gas, so as not to be operated on alternate strokes of
the piston when the engine is running under a variable pressure of the gas. The
gas admission valves are also further controlled by a governor, which automatically
regulates the amount of gas admitted into the cylinder according to the speed of the
engine. The engine is provided with igniters for the gas, which are automatically
controlled as will be described, so as to effect an explosion of the gas at each
reciprocation of the piston when the engine is running under constant pressure,
and at alternate reciprocations of the piston when the engine is running under a
variable pressure.
C
These and other features of this invention will be pointed out in the claim at the
end of this specification.
Fig. 1 is a top or plan view of a gas engine embodying this invention.
Fig. 2, a front elevation of the engine shown in Fig. 1.
Fig. 3, a detail on a larger scale and in front elevation of the right hand portion-
of the engine shown in Fig. 2.
Fig. 4. a sectional detail on the line 4, 4; Fig. 1.
Fig. 5, a detail of the valve operating mechanism to be referred to.
TR a tan ar plan view of the mechanism shown in Fig 5

page_text: Figs. 7, 8 and 9, details to be referred to, Fig. 9 being a section on the line 9-9,
Fig. S.
Figs. 10 and 11, details to be referred to.
Fig. 12, a sectional detail on an enlarged scale on the line 12-12, Fig. 1, and
Figs. 13, 14, 15, 16, 17, 18 and 19, details to be referred to, Fig. 15 being a
section on the line 15-15, Fig. 6, looking toward the right.
T
In the present embodiment of this invention, A represents the cylinder of the
engine, provided with water jackets or spaces A at its ends and around its
body portion, and with the piston A2 (see dotted lines Fig. 1), having its piston
rod A³ joined by the connecting rod Ato a-crank pin. A on a crank or disk A
fast on the main shaft A having bearings in the base or framework As.
The cylinder A has secured to it preferably on one side at its opposite ends, two.
sets of valve casings aa¹, a², the casings aa containing the gas admission
valves aa (see Fig. 3), and the casings a containing the exhaust valves as a
The valves aaaa are preferably niade as piston valves co-operating with
suitable seats in their respective valve casings, and provided with valve
rods as a a¹º 12 (see Fig. 3), which are extended up through the heads or upper
ends of the valve casings, and each of which is secured to an actuating mechanism
as will be described. Inasmuch as the actuating mechanisms for all the valves
are the same, I will specifically describe the construction of but one, which may be
supposed to be that which operates the admission valve at. The actuating mechanism
referred to, consists essentially of a rock-shaft 20 (see Figs. 5, 6 and 15) having a
bearing in a standard or upright a2 erected upon the head of the valve casing. The
rock-shaft at one end has fast on it a crank or arma, having its end rounded or
provided with a ball 23 (see Figs. 6, 18, and 19), which enters a slot at in the
end of a bar or rod as fastened to the valve stem a³, so that when the rock-shaft 20
is moved in the direction indicated by the arrow 20, Fig. 5, the valve a will be
lifted from its seat so as to permit the gas or gas and air to pass into the cylinder A,
The rock-shaft a 20 at its opposite end has fast on it a second crank or arm a³,
carrying a bolt provided with a square or other than round head a (see
dotted lines Figs. 6 and 16), which is adapted to be engaged by an arm
provided with a latch or hook and fast on a shaft having bearings in a hub a
attached to a crank or arm 3, extended from the sleeve or hub, loosely
mounted on the end 2 of the hearing hub for the rock-shaft 20 and provided with a
second arm or crank a40. The sleeve or hub is adapted to be operated by an
eccentric a¹ on the main shaft A, and which eccentric for the purpose of this
invention I prefer to designate as the main eccentric. The eccentric a as shown
in Fig. 2, is joined by a rod at to a lever a pivoted to the framework and connected
by a rod a to a wrist plate a, pivotally mounted on a stud or bracket at attached
to the side of the cylinder A (see Fig. 1).
The wrist plate is joined by a link or rod a to the crank or arm 40.
From the above description, it will be seen that at each revolution of the main
shaft A, the crank or arm at of the sleeve a will be actuated to lift the valve at,
if the latch or hooked arm is in position to engage the head a of the bolt a
When the engine is running as a constant pressure engine at normal speed, the
latch or arma is in proper position at all times to engage the head of the
bolt, and lift the valve once for every revolution of the main shaft, and conse-
quently lift the valve once for every complete reciprocation of the piston A².
The latch arm is held in its proper position until positively removed therefrom
by tripping devices or mechanisms as will be described, by means of a spring a 50
attached at one end to the crank or arm a, (see Fig. 5).
In order to enable the engine to be automatically converted from a constant
pressure engine into a variable pressure engine, provision is made by which the
latch is disengaged on every alternate revolution of the main shaft A. This result
is effected in the present instance. by providing the rock-shaft with a crank or
arm a extended downward toward the rock-shaft a20, so that the crank or arm al
may be engaged at the proper time by suitable cams, as will be described, so as to turn

page_text: the rock-shaft a3 in its sleeve a and remove the latch arm a from its operative
position with relation to the head of the bolt a³¹.
Referring to Figs. 5, 6 and 15, the bearing hub supporting the rock-shaft a20
is made of different diameters to form bearings 2-3 for the sleeve and. a
lever ass, and for a sleeve or hub a provided with a crank or arm a, the sleeve a
having secured to it by a key as a grooved collar or ring The groove collar
or ring a, shown separately in Figs. 7, 8 and 9 is provided with a projection, a
constituting one of the cams, which is adapted to engage the crank or arm a
and the lever as is also provided with a thickened or cam surface a (see Fig. 15),
which cam is also adapted to be brought into engagement with the crank or
arm a The grooved collar or ring is adapted to be moved longitudinally
on the sleeve a in the direction indicated by the arrow 40, (Figs. 6 and 15) so as
to bring its cam surface into line with the crank or arm al, and to be moved
in the direction opposite to that indicated by the arrow 40, so as to remove the
cam projection, which constitutes the tipping device for the latch arm a, from
in line with the crank or arm a³. These movements of the grooved collar a and
its cam a, in accordance with this invention, are automatically effected by the
pressure of the gas admitted into the admission, valve cylinders, so that when the
gas is of a constant or high pressure, the cam a may be moved out of line with
the crank or arm a in the direction opposite to that indicated by the arrow 40;
namely, into the position shown in Fig. 15, and when the pressure of the gas is
reduced and it is desired the engine should operate under variable pressure; the
cam will be moved into line with the crank or arm. 51 and in the direction
indicated by the arrow 40 and into the position shown in Fig. 6.
The mechanism by which these movements of the sleeve a and its attached
cam ab are effected, may and preferably will be such as will now be described.
The grooved collar is adapted to be engaged by a yoke a70 (see Fig. 3)
having an arm, which is pivoted as at a on top of the valve casing a. and
is connected at its upper end by a link or rod to a crank or arm. fast on
a rock-shaft a, supported in suitable bearings on top of the engine cylinder A,
and provided at one end with a crank or arms, to which is pivotally connected
a piston rod (see Fig. 3) of a piston 84 (see dotted lines Fig. 3), contained
in a cylinder provided at its lower end with a gas inlet pipe, which com-
municates as hereinshown by a branch pipe 8 with a chamber a, with which
directly communicate the valve casings and a, and which chamber is provided
as shown in Fig. with a high pressure supply pipe and a low pressure supply
pipe, the high pressure supply pipe being provided as hereinshown with
a throttle valve a, and the low pressure supply pipe being provided with
an automatically operated valve
The main supply pipe is adapted to be connected with a suitable reservoir
containing gas or gas and air under high pressure, and the pipe is adapted
to be connected with a suitable reservoir containing gas or gas and air under a
lower pressure. These reservoirs are not hereinshown as they form no part of
my invention and are well known.
From the above description, it will be seen that the pressure in the cylinder 85
acting on the underside of the piston as is the same as that in the chamber a 88,
and that when the gas of high pressure is supplied to the chamber as, it is
admitted to the cylinder a and acts to move the piston upward in the direc-
tion indicated by the arrow 60, (Fig. 3) which upward movement rocks the
shaft in a rearward direction, and by means of the link a draws the grooved
collar and its attached cam into the position shown in Fig. 15, that is,
so that the cam is moved out of line with the crank or arm a, and as long
as the pressure of the gas is sufficient to keep the piston 8 elevated, the cam a
will be held in its withdrawn position with relation to the crank or arm, and
the admission and exhaust valves of the engine will be operated from the main
eccentric through the wrist plate a
When the cam is withdrawn from in line with the crank or arm a

page_text: the engine is operating as a constant pressure engine, and the gas or gas and air
admitted into the cylinder behind the piston, when the latter is at one end
thereof, is exploded by means of an igniter B, which may be of any usual or
suitable construction and communicates with the outlet port or passage b (see
dotted lines Fig. 1) from the valve casing a.
The valve of the igniter B has connected to its valve rod (see Fig. 3) a
piston located in a cylinder 3 provided at its upper end with a gas inlet
pipe +, which is connected to the pipe, so that high pressure gas may be
admitted into the cylinder 63 above the piston and force the same downward
against the action of a spring 65 located in the said cylinder. The downward
movement of the piston 62 by the high pressure gas serves to keep the igniter
valve constantly open, as long as the engine is working as a constant pressure
engine. When, however, the pressure of the gas is diminished, the spring b
acts on the piston 63 and closes the igniter valve, and the latter is then opened
at the proper time to enable the engine to be worked as a variable pressure
engine, as will be described.
When the engine has been started as a constant pressure engine and is running
in the proper manner, the throttle valve as may be closed, and the proper con-
nection made with the reservoir containing the gas and air under low pressure,
which is admitted into the chamber through the pipe a", the valve being
automatically opened by the pressure of the gas and held open against a stop b
shown by dotted lines in Fig. 3.
The diminution of gas pressure in the chamber ass is immediately felt in
the cylinders 8, 63, and, as a result, the piston is permitted to descend by
gravity, in the present instance, and the piston 62 is moved upward by the
spring. When the pressure in the cylinder 85 has been sufficiently reduced,
the piston as descends and moves the rock-shaft a", and by means of the link
connection and yoke a, moves the cam collar in the direction indicated
By the arrow 40, and places the cam or tipping device a into line with the
crank or arm (see Fig. 6) so that on every alternate revolution of the main
shaft, the cam is engaged with the crank or arm and is moved
in the direction indicated by the arrow 20, Fig. 5, SO as to carry
the crank or arm and the latch arm 31 in the direction indicated
by the arrow 80, Fig. 5, which will trip or remove the latch from
operative position with relation to the head on the bolt, and thereby
enable the sleeve to be rocked on its bearing 2 without engaging the latch
with the head of the bolt and consequently without lifting the valve at.
The collar 5 may be rocked at alternate reciprocations of the piston A° as
hereinshown, by one of two eccentrics 620, 1,21 mounted on a shaft 2 suit-
ably supported in the framework of the engine, and provided with a large gear
which meshes with a pinion or gear of one half its size, fast on the
main shaft A, so that the shaft may make one revolution to every two revolu-
tions of the main shaft. In the present instance, I have represented the
eccentric 620 as operatively connected to the collar a so as to rock the same,
the said eccentric being joined by a link or rod 2 to one end of a lever
pivoted at 6, and having its other end joined by a link or rod to the crank
or arm of the collar 59.
The eccentric is connected in a similar manner by link 60, lever 1,
pivoted at , and link or rod to the crank of the collar a governing
the operation of the admission valve a at the opposite end of the cylinder A.
The eccentrics 2021 constitute the auxiliary or variable eccentrics and are
.connected to the cranks a", which govern the operation of the exhaust valves a³, a
at the opposite ends of the cylinder A, the crank 7 for the exhaust valve a
being connected as hereinshown, by link 640 and lever b1 to the rod 6s, while
the crank a for the exhaust valve a is connected to the rod.
From the above description, it will be seen, that in the double acting engine
hereinshown, the admission valve at at one end of the cylinder A and the

page_text: exhaust valve a' at the opposite end of said cylinder are controlled by the same
eccentric substantially simultaneously, while the admission valve a³ and
exhaust valve are simultaneously controlled by the eccentric 2.
The admission valves at a are also operatively connected to the governor G,
which may be of any usual construction and which as hereinshown, has its mov-
able sleeve joined by a link to a crank 662 on a rock-shaft 6, having
a crank 66 which is joined by a rod or link to the lever a, the said lever
having the cam 6 and as shown in Fig. 3, an arm b, joined by a link 667 to
the lever a for the admission valve a. This connection with the governor
enables the amount of gas admitted into the cylinder A to be controlled according
to the speed of the engine, for when the speed of the engine is normal, the
cam a remains inactive with relation to the arm a, but when the speed becomes
excessive, the said cam is brought into position to act on the arm and thereby
disengage the latch arm from the crank arm before the valve at has
been opened to its fullest extent, consequently diminishing the amount of gas
admitted into the cylinder, and thereby reducing the speed to normal, and when
this normal condition has again been attained, the valve a is opened wide by
the latch arm 34.
When the engine is running as a variable pressure engine, it is required that
the valves for the igniters B B should be operated at the proper time, which is
effected by placing the said igniter valves under the control of the eccentrics 620, 621.
The connection between the eccentrics 620 61 and the igniter valves, may and
preferably will be accomplished as hereinshown and as will now be described.
Referring to Figs. 1, 2 and 3, the levers 26, 631 have connected to them one
end of rods or links 680, 81, joined at their opposite end to levers 68, 683, pivoted
as at 84, 85 and having arms 66, 67, which have a sliding engagement with
the valve rods b', 6, of the igniter valves, and which are adapted to engage
collars, on said valve rods to open the igniter valves against the action of
the springs. The collars 60, 91 are placed on or secured to the valve rods,
so that the arms 686, 687 may be moved up and down on the valve rods without
engaging said collars, when the engine is running as a constant pressure engine,
the pressure admitted into the cylinders above the pistons be moving the
collars 60, down beyond the range of movement of the arms 68, 687, but
when this pressure is reduced, the springs close the igniter valves and bring
the collars, 91 up into position to be engaged by the arms 63, 87, which
operate at the proper time to open the igniter valves and explode the charge
compressed within the cylinder A, as is now practised in four cycle gas engines.
I have hereinshown and described, one mechanical construction and arrange-
ment whereby a gas engine may be started as a constant pressure engine and to
be automatically converted by diminution of pressure into a variable pressure
engine, but I do not desire to limit my invention to the precise mechanical
construction shown.
Furthermore, the invention hereindescribed is applicable to either a single acting
or a double acting engine, and that in the double acting engine, the
admission valve at one end and the exhaust valve at the other end
of the cylinder work in pairs. The valve casings aaare provided with
suitable devices to prevent flashing back, and, 111 the present instance,
these devices are shown as a series of pencils, rods or pins f, projecting
from a cap or plate fi adapted to be bolted to the top of the valve casings, the
said pencils or rods being arranged in circles as shown in Figs. 10 and 11, and
have the same effect as the well known wire gauze or perforated plate to prevent
the passage of the flame.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:-
1. A gas engine comprising a cylinder provided with a gas admission valve,

page_text: and with an exhaust valve, mechanism to actuate said valves, and means respon-
sive to the pressure under which the engine is working to automatically operate
said valve-actuating mechanisms and convert the engine automatically from a
constant pressure engine into a variable pressure engine, substantially as described.
2. A gas engine comprising a cylinder provided with a gas admission valve
and with an exhaust valve, actuating mechanisms for said valves, a main shaft,
an eccentric on said shaft connected to said valve actuating mechanism to operate
it at every revolution of the main shaft, an auxiliary eccentric, and mechanism
connected to said auxiliary eccentric and co-operating with said valve actuating
mechanism, and means operated by the pressure of the gas admitted into said
cylinder to render active the mechanism connected to the auxiliany eccentric
and thereby control the operation of the valves, substantially as described.
3. A gas engine comprising a cylinder provided with a gas admission valve
and with an exhaust valve, actuating mechanisms for said valves, mechanism
operated by a predetermined pressure to place the said valve actuating mechanism
in condition to be operated to open the valves at each complete reciprocation of
the piston in said cylinder, and responsive to a diminution from said predeter-
mined pressure to place said valve mechanism in condition to be operated to open
the valves at alternate reciprocations of said piston, substantially as described.
4. A gas engine comprising a cylinder provided with a gas admission valve
and with an exhaust valve, a gas igniter controlling the ignition of the gas
admitted into said cylinder, valve actuating mechanisms for said admission and
exhaust valves, a wrist plate connected to said valve actuating mechanisms, a
main eccentric connected to said wrist plate, means co-operating with the valve
actuating mechanisms and responsive to a predetermined pressure to render said
valve mechanisms responsive to each revolution of the said main eccentric, an
auxiliary eccentric, and means connected to said auxiliary eccentric to render the
valve actuating mechanism responsive only to alternate revolutions of the main
eccentric, substantially as described.
5. A gas engine comprising a cylinder provided with a gas admission valve
and with an exhaust valve, actuating mechanisms for said valves, each comprising
a rock-shaft 20 connected to the valve and provided with a crank or arm
having a projection, a sleeve provided with a crank a rock-shaft
carried by said crank and provided with a latch or arm to engage the projec-
tion, and with an arm, a sleeve a provided with a crank or armr, a collar
keyed on the sleeve 456 and provided with a cam, means to rock the sleeve to
lift the valve, means responsive to the pressure of the gas to move the said collar
on the sleeve 56 to move its attached cam into and out of line with the crank
or arm, and means to rock the sleeve a substantially as described.
6. A gas engine comprising a cylinder provided with a gas admission valve
and with an exhaust valve at its opposite ends, a gas igniter co-operating with
each of said gas admission valves, a valve actuating mechanism for each of said
admission and exhaust valves, a piston in said cylinder, a main shaft to which
said piston is connected, a main eccentric on said main shaft, a wrist plate con-
nected to said main eccentric and to which the actuating mechanisms for said
valves are connected, auxiliary eccentrics driven from the main shaft and revolv-
ing at a slower speed than the main eccentric, a tripping device for each of said
valve actuating mechanisms operated by said auxiliary eccentrics, means to
operatively connect the valves of said igniters to said auxiliary eccentrics, and
means responsive to the pressure of the gas admitted into said cylinder to render
the tripping device active or inactive according to said gas pressure, substantially
as described.
7. A gas engine comprising a cylinder provided with a gas admission valve
and with an exhaust valve at its opposite ends, a gas igniter co-operating with
each of said gas admission valves, a valve actuating mechanism for each of said
admission and exhaust valves, a piston in said cylinder, a main shaft to which
said piston is connected, a main eccentric on said main shaft, a wrist plate con-

page_text: nected to said main eccentric and to which actuating mechanisms for said valves
are connected, auxiliary eccentrics driven from the main shaft and revolving at
a slower speed than the main eccentric, a tripping device for each of said valve
actuating mechanisms operated by said auxiliary eccentrics, means to operatively
connect the valves of said igniters to said auxiliary eccentrics, and means respon-
sive to the pressure of the gas admitted into said cylinder to render the tripping
device active or inactive according to said gas pressure, a second tripping device
for the gas admission valves, and a governor connected to said second tripping
device, substantially as described.
8. A gas engine comprising a cylinder provided with a gas admission valve
and with an exhaust valve, actuating mechanisms for said valves, and tripping
devices for said admission and exhaust valves responsive to the pressure of gas
employed to run the engine to automatically change the engine from a constant
pressure to a variable pressure engine, substantially as described.
Dated the 14th day of March 1899.
D. YOUNG & Co.,
11 & 12, Southampton Buildings, London, W.C.,
Agents for the Applicant.