Improvements in Construction and Method of Operating Gas Engines.
Year: 1886

page_text: COMPLETE SPECIFICATION.
Improvements in Construction and Method of Operating Gas
Engines.
I, LEWIS HALLOCK NASH, residing at, 379, Gates Avenue, Brooklyn, in the
County of Kings and State of New York, in the United States of America,
Mechanical 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:-
My invention is directed to improvements in gas engines having co-acting
power cylinders of unequal capacity in the one of least capacity the charge is
ignited, and into the one of greatest capacity the ignited charge is transferred to
complete its expansive force to continue the force of such expansion as a secondary
power. The objects of my improvements are, to operate a gas engine with a
highly compressed charge and utilize the primary expansive force thereof in the
ignition cylinder, to continue the force of such expansion within the coacting
cylinder of greater capacity; to utilize the waste heat of the primary power
cylinder to heat the cylinder of the secondary power; to prevent the loss of
the heat from the hot gases; to govern the speed and power of the engine by
the manner in which the charge is admitted to the power cylinder in connection
with the method of expanding the charge; to relieve the piston connecting
mechanism and bearings from injurious strain and pressure; to render more
uniform the force exerted by the engine in contradistinction to short intense
impulses that are so destructive to the wearing parts of gas engines. In my
improved gas engine the admission and ignition of the charge, in connection with
its secondary expansion, is utilized as the means of governing the engine by
controlling the operation of the governor. In these particulars my invention
comprehends matters of construction, of combinations and of methods of operating
a gas engine; and of transmitting the heat by a circulating heat conveying medium
from one power cylinder to the other as a means of utilizing the waste heat of the
engine.
Referring to the accompanying drawings,—
Figure, 1, represents a horizontal longitudinal section taken centrally through
the coacting power cylinders, showing the primary piston on its forward stroke
and the secondary piston ready to receive the expanding gases from the primary

page_text: Figure, 2, a vertical longitudinal section taken through the primary power
cylinder, showing the piston at the beginning of its back stroke and also showing
the secondary piston in position in dotted lines on its forward stroke.
Figure, 3, a cross section taken on the line, x-x, of figure, 1, showing the
position of the valves.
Figure, 4, a similar section taken on the line, y-y, of figure, 1, showing the
heat conducting jacket of the co-acting cylinders.
Figure, 5, a similar section showing the heat conducting jackets of the two
cylinders when the latter are separated from each other. Figure, 6, shows a
diagram, illustrating the path of the two cranks and the action of the gases in
each cylinder.
Figure, 7, shows a longitudinal section of the governor with its eccentric
connections.
Figure, 8, shows a cross section of the same on the line, a-a, of figure, 7.
The
The engine is constructed of two cylinders, a, 'and, 'b, which I denominate the
primary and the secondary power cylinders. The primary cylinder forms the com-
bustion chamber, c, and is of less capacity than the chamber of the secondary
cylinder, with which it has valved communication as hereinafter described.
cylinders are preferably cast together and form the bearings for the pistons;
while the chambers in which the charge operates, are preferably cast in a separate
cap-piece, d, which is secured to and forms an extension of the cylinders. This
cap or hood has an enveloping space, e, formed within its walls in which a heat
conveying fluid, such as quick silver, or lead is placed, and caused to circulate by
the heat from the combustion chamber. This cap or hood is enveloped by a non-
conductor, f, for retaining the heat. At the joining of the chambered cap, d, with
the cylinders there is a thick packing to prevent the conduction of the heat to the
bearing cylinders. By this heat conveying medium the combustion chamber is
prevented from becoming unduly heated as the waste heat from it is taken up and
conveyed to the secondary cylinder and utilized to increase the expansive force of
the gases therein contained, whereby a large economy of power is obtained.
The pistons, h, and, i, of the respective cylinder chambers operate free of the
walls thereof and therefore are not heated to any extent by the combustion of the
charge. The bearing cylinders are formed with a cooling jacket, g, but by the con-
struction of the separate hood for the hot gases, the bearing cylinders may not
need a cooling jacket. The pistons are preferably of trunk form and are connected
to the crank-shaft as shown in figures, 1, and, 2. The engine valves, j, are arranged
upon the cool cylinders and passages, k, lead from the valves into and through the
walls of the hood or cap and open at, k¹, into the chambers back of the pistons,
through which the charges are admitted into and discharged from said chambers.
By thus placing the valves in the cool bearing cylinders, and forming passages
leading from them through the hood extension, I obtain the advantage of using
comparatively cool valves without the necessity of cooling the combustion chamber
which must be done when the valves are placed upon the combustion chamber.
In engines of large dimensions I prefer to separate the cylinders and maintain the
flow of the heat conveying medium of the cylinders by connecting pipes which
should be covered by non-conducting material as shown in figure, 5. The valves
are single admission slide valves arranged one at the outer side of each cylinder,
and one between them and they are all operated by eccentrics, l, m, on a counter-
shaft, 72, as shown in figure, 3.
The countershaft, 13, is operated by a second counter shaft, 13, driven by bevel
gearing from the crank shaft, A, as shown in figure, 1. The governor, n, is carried
by the countershaft, 12, as seen in figures, 3, and, 7, and is of the type known as
the ball governor having its balls controlled by a spring, n¹. The governor arms
engage with a slide, n², which engages by edge-pins, n³, with spiral slots, n', formed
in the eccentric, l, which is mounted loosely upon the countershaft, 12, so that any
longitudinal movement of the governor-slide, n³, will cause the eccentric, l, to
revolve and thereby regulate the action of the supply-valve, j. The middle-valve, j¹,

page_text: figures, 1, and, 3, operate to admit the charge from the primary cylinder into the
secondary cylinder; while the valve, j³, figure, 3, controls the exhaust and the
valves, 1, 3, are operated by eccentrics fixed upon the countershaft, 1. The
exploding of the charge in a comparatively small cylinder and expanding it in a
large cylinder causes the intensely high pressure of the gases at ignition to act
upon a comparatively small piston and therefore the piston connecting mechanism
and the bearings are relieved from injurious pressure; and the power of the gases
under such high pressure, instead of being exerted through a very short movement
of the piston, is exerted upon the small piston during a much longer portion of the
stroke, whereby the force exerted by the engine is much more uniform instead of
being subjected to a series of short and intense impulses as is usual in gas engines,
and to withstand which the engine has been constructed with great weight and
strength of connections as compared with the power developed.
The operation of the engine is as follows, viz;-The pistons being in the positions
shown in figure, 2, the piston, i, of the primary cylinder on its forward stroke and
the supply valve just opening, a combustible charge is admitted under a considerable
pressure to the combustion chamber, c, by the pipe, s, through said valve, the point
of such admission being indicated at, 1, in figure, 6, and such admission terminating
at, 2. From this point the charge is compressed by the back stroke of the piston
to a very high degree. Just after the piston commences its next forward stroke
the charge is ignited at, 3, and expanding, drives the piston forward. When it has
reached the position shown in figure, 1, and at, 4, figure, 6, the valve, j, opens
communication with the chamber of the secondary cylinder, admitting the charge
to continue its operation upon the large piston, which at this moment is at the
beginning of its forward stroke as shown in figure, 1, and at, 5, in figure, 6. The
two pistons are now driven forward by the expansion of the charge until they
reach the position shown in figure, 2, in full and dotted lines, at which time the
crank, B, of the primary piston is at, 1, figure, 6, and the crank, C, of the secondary
piston is at, 6, in said figure.
The valve, j, now closes communication between the two cylinders, a new charge
is admitted to the primary piston, and at the same time the gases continue to act
in the secondary cylinder forcing its piston to the end of its stroke as indicated
at 7, in figure, 6. The exhaust valve, j, now opens, discharging the gases until
the crank, C, reaches the point, 8, figure, 6, when valve, j, closes the exhaust and
the remaining backward movement of the piston fills the clearance space with
compressed gases, thus completing the circuit of both cranks.
The governor acts as follows, viz;-When the engine is working to its greatest
capacity the governor operates the valve to admit the charge to the primary cylinder
at the point, 1, figure, 6, and closes the admission at the point, 2, having thus
admitted a charge while the piston is on its extreme forward stroke. When less
power is required of the engine the governor operates the valve to open the admission
later and closes it later as indicated by the dotted points, 9, 10, in figure, 6, the
charge thus being admitted after the piston has completed a portion of its back
stroke into a chamber. of less capacity, therefore a lesser charge can be admitted
proportioned to the cylinder space. The governor effects the above operation by
its action in rotating the eccentric, l, through a greater or less arc and thus cause
the supply valve to open and to close more or less early in the back stroke of the
piston.
I prefer to place the two co-acting cranks for the two cylinders in the relative
position shown in figure, 2, in which the secondary cylinder receives the pressure of
the gases before the primary piston has completed its forward stroke; for, by this
construction the secondary piston exerts its force upon its crank during the latter
part of the stroke of the primary piston and it accomplishes a larger part of its
stroke at the time the primary piston has completed its stroke. In this operation
the small power cylinder is supplied with a combustible charge under compression
which is further compressed by the back stroke of the piston, ignited and partially
expanded therein and the expansion of the gases is completed in a cylinder of

page_text: greater capacity; and, in this operation the waste heat from the small cylinder is
conveyed by a medium caused to circulate around the latter by the heat thereof to
and around the larger and cooler cylinder and thereby heat one cylinder from the
other, prevent the combustion chamber from becoming unduly heated and increase
the expansive force of the gases in the secondary power cylinder. For the heat
transmitting medium I may use an alloy rendered fusible by the heat from the
combustible chamber, so that when once reduced to a liquid form it will circulate
from the hotter to the cooler cylinder upon well known principles which govern
the circulation of hot water for heating purposes.
The invention comprehended broadly in a gas engine having co-acting power
cylinders of unequal capacity, into the one of least capacity the charge is ignited,
and into the one of greatest capacity the charge is transferred to complete its
expansive force, is old in the state of the art, but my improvements are directed
to and comprehended in the following specific matters in such an engine.
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
1st. The combination, with the power cylinder of a gas engine, of a hood exten-
sion therefor, having ports or passages within its walls opening into the combustion
chamber behind the piston, and valves arranged to communicate with said hood
wall passages, substantially as described, for the purpose specified.
2nd. The combination of the two co-acting power cylinders and their co-acting
pistons, with a hood extension for each forming communicating combustion and
expansion chambers for the gaseous charge, and suitable valves for controlling
such communication, the inlet and the exhaust, substantially as described.
3rd. The combination, in a gas engine, of two co-acting power cylinders forming
the bearings respectively of two co-acting pistons, of unequal size, and the engine
valves arranged upon said bearing cylinders, with a hood extension having interior
wall passages or ports leading from said valves into the chambers of said cylinders
back of said pistons, substantially as described, for the purpose specified.
4th. The combination, in a gas engine having a cylinder chamber for receiving
and exploding the charge and a separate communicating cylinder chamber for
expanding the charge, of a heat conveying jacket adapted to enclose both chambers
containing a heat conveying fluid, whereby the heat from the combustion chamber
is conveyed to the expansion chamber to increase the expansive force of the gas
therein.
5th. The combination, in a gas engine, of two co-acting power cylinders and their
co-acting pistons of unequal size, with valves, j, j, j³, their operating eccentrics, the
crank-shaft, and the governor, substantially as described, for the purpose specified.
6th. The combination, in a gas engine, of two co-acting power cylinders having a
cooling water jacket, g, with a hood extension forming communicating combustion
and expansion chambers for the gaseous charge having enveloping space, e, containing
a heat conveying medium, whereby to convey the waste heat from the combustion
around the expansion chamber, for the purpose described.
7th. The method herein described of governing the speed and power of a gas
engine, which consists in admitting the combustible charge during the back stroke
of the piston and regulating the quantity of the charge by cutting off the admission
at different points in the back stroke of the piston by means of a governor, whereby
to regulate the power of the engine.
8th. The method herein described of utilizing the waste heat from the combustion
chamber of a gas engine, which consists in expanding the charge in two co-acting
power cylinders and conveying the waste heat from the hotter to the cooler power
cylinder by the circulation of a heat conveying fluid, thereby increasing the
expansive force of the gas in the cooler cylinder.
9th. The method of utilizing the expansive force of the charge of a gas engine,
which consists in igniting the charge in the combustion chamber and completing

page_text: the expansion thereof in an adjacent cylinder-chamber heated by the waste heat of
the combustion chamber, substantially as described, for the purpose specified.
10th. The method herein described of operating a gas engine which consists in
supplying a small cylinder with a combustible charge under compression, further
compressing the charge by the back stroke of the piston, igniting and partially
expanding the charge so compressed in said small cylinder and completing the
expansion of the gases in a cylinder of greater capacity, substantially as described.
11th. The method herein described of utilizing the waste heat from the com-
bustion chamber of a gas engine, which consists in expanding the charge in two
co-acting cylinders and conveying the waste heat from the hotter to the cooler
power cylinder through the medium of quicksilver or other circulating medium
caused to circulate by the heat from the combustion chainber, as described, whereby
to prevent the combustion chamber from becoming unduly heated and to increase
the expansive force of the gases in the cooler power cylinders.
Dated this 18th day of May 1886.
WP THOMPSON & BOULT,
Agents.