Year: 1888

page_text: Date of Application, 22nd May, 1888
Complete Specification Left, 22nd Mar., 1889
Complete Specification Accepted, 18th May, 1889
We THOMAS BROWETT and HERBERT LINDLEY Engineers of Sandon Engine
Works Saint Simons Street Salford Manchester in the County of Lancaster do
hereby declare the nature of this invention to be as follows:--
Our Invention relates to that class of Gas Engine known as the "two revolution"
gas motor Engine wherein a working impulse is produced at every alternate
outstroke of the piston when the motor is developing its full power and has for its
object the simplification of such Engines together with an increased officiency of
same by reason of a greater expansion of the ignited charge than has hitherto been
obtained in such engines, and our invention consists in means and arrangements
whereby such simplification and increased efficiency and economy can be obtained
and in means and arrangements whereby the supply of gas or liquid hydro-carbon
can be automatically adjusted to the varying requirements of such engines.
In an engine constructed according to our invention we have a cylinder provided
with a piston and connected by a suitable connecting rod to a crank shaft running
in bearings and provided with a 'fly wheel in a manner now well understood. The
cylinder is constructed with a clearance space at its rear end beyond the extreme
inward position of the piston the volume of such clearance being determined by the
pressure to which it is desired. to compress each volume of combustible charge
previous to ignition. The action of the engine is as follows:-Supposing the piston
to be at its dead centre, that is at the extreme end of its stroke away from the crank
shaft, it commences to move outwards drawing in a charge of combustible vapour and
air through suitable ports or passages controlled by valves hereinafter to be more
fully described. After a certain and predetermined portion of its outstroke the
supply of combustible mixture or charge is cut off and the remainder of this
outstroke acts in rarefying the contents of the cylinder. The return of the piston
compresses the charge, at first to atmospheric pressure and afterwards to any desired
extent into the clearance space provided for it at the end of the cylinder. The
charge is then ignited and a working stroke effected, the expansion of the ignited
gases being carried to the full range of the piston's travel. The next instroke,
performed by the momentum of the fly wheel, expels the burnt gases through a
valve opened for this purpose and the cycle is completed.

page_text: In order to effect and control the supply of the charge to the cylinder we employ a
valve which may either be a flat slide valve or a sliding piston valve, in combination
with a back pressure valve, so that, during the combustion of the charge the sliding
surfaces are protected from the heat of the ignition. The presence of this back
pressure valve between the sliding valve and the cylinder also enables us to use the
sliding valve as an exhaust valve by reason of its closing the passages leading to the
sliding valve at such times as they would, without such back pressure valve, be
wrongly open. The increase in the expansion of the ignited gases obtained by these
means considerably reduces their temperature so that it is possible to use a sliding
valve for the emission of the exhaust but in addition thereto we sometimes provide an
exhaust port or holes to be uncovered by the piston when near its extreme outstroke
by which device at the end of a working stroke any pressure in the cylinder above
the atmosphere is got rid of through such port or holes, and the temperature of the
cylinder is reduced by the expansion of its contents. Such holes or port must be
provided with a valve or its equivalent in order to prevent the inrush of air or of
burnt gases from the exhaust pipe when a partial vacuum occurs on the next
outstroke as previously explained. In the combination of sliding valve and back
pressure valve the latter is required to be mechanically lifted in order to allow the
exhaust to escape through the passages which the sliding valve is opening for that
purpose as well as for the entrance of the next charge which is immediately
afterwards drawn in, the said back pressure valve automatically closing as soon as the
entrance of fresh charge is cut off by the sliding valve.
The firing of the charge may be effected in any of the ways now well known and
when it is desired to fire by flame contact the same sliding valve that controls the
entrance of the combustible charge may be utilized for that purpose. In order to
govern the engine the supply of gas or hydro-carbon may be cut off or diminished in
quantity and air or a weaker mixture only drawn in. In order to adapt the engine
for using liquid hydro-carbon instead of coal gas we can take advantage of the
partial vacuum occurring in the cylinder on the charging stroke to draw in a
portion of the liquid into the cylinder through a suitable valve a
supply of air
having been previously drawn in for a portion of the stroke of piston, the
vaporization of the liquid being assisted considerably by the reduction of pressure in
the cylinder.
In an engine constructed according to this invention the governing may be
effected by the action of a separate exhaust valve which is allowed to remain closed
and to cause the waste products, or any portion thereof, to be retained in the cylinder
and compressed thus preventing or delaying the formation of a vacuum and the
entrance of a new charge in the manner described in the specification of a former
application made by us numbered 11345 dated 19th August 1887.

page_text: We, THOMAS BROWETT and HERBERT LINDLEY, Engineers of Sandon Engine
Works, St. Simon Street, Salford, Manchester, in the County of Lancaster, 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:-
This invention has reference to gas engines of the kind wherein a combustible charge
of
gas and air is compressed and fired once in two revolutions of the engine and
relates to improved means and arrangements for carrying out this cycle of opera-
tions and to the simplification and improvement of the means whereby the governing
of such engines can be effected and the admission of the combustible gas or vapour to
the cylinder be controlled.
In order to effect the proper admission to the cylinder of the engine, of a combus-
tible charge of gas or vapour (such as hydro-carbon vapour) and air, we employ a
sliding or rotating piston valve (or a sliding valve, that may if preferred, be of a
flat or rectangular form) operated by an eccentric or crank placed on a shaft rotating
at half the speed of the engine shaft, in combination with a mechanically operated
lifting check valve, placed between the sliding valve and the cylinder, the sliding or
rotating valve (hereinafter referred to as the sliding valve), serving to direct the
ingoing and outgoing currents to and from the cylinder and the check valve serving
to protect the surfaces of the sliding valve from the heat and pressure due to the
ignitions in the cylinder by reason of its being closed at such times, and also serving
to prevent any escape of gas from the cylinder past the sliding valve, until the proper
moment for the emission of the burnt gases, (when the check valve is mechanically
lifted) the ports leading to the cylinder and which are uncovered by the motion of the
sliding valve, being open before the lifting of the check valve and therefore too soon
for the correct working of the engine. The sliding valve therefore merely performs
the function of connecting the port leading to the cylinder with the air suction pipe
at such times as air is required to be drawn into the cylinder, and of afterwards placing
such port in communication with the exhaust pipe so that when the check valve is
lifted the burnt gases are expelled through the exhaust pipe. The sliding and check
valves are capable of being so set as to admit air, or gas and air to the cylinder in
auy desired quantity or manner, but we prefer to admit air only, and for a portion
only of the suction stroke of the piston, such air being afterwards impregnated with
gas or hydro-carbon a vapour from a supply pipe of such gas or vapour, the valve by
which such gas or vapour is admitted to the cylinder being under the control of the
governor, so that when the speed of the engine is too high the valve is not opened, and
gas or vapour is not drawn into the cylinder. It will be seen that as air is only
drawn into the cylinder for a portion of the suction stroke of the piston, there exists
a partial vacuum therein at the end of such stroke and gas or vapour is readily sucked
or drawn into the cylinder and diffused in the air contained therein.

page_text: In order that our invention may be clearly understood we have appended hereto two
sheets of illustrative drawings that we will now proceed to describe.
Figs. 1 and 2 are respectively a side elevation and a plan of a gas motor engine
constructed according to our invention.
Figs. 3, 4, and 5, are respectively a cross section a vertical longitudinal section, and
a horizontal section of the valves, and adjacent parts of the motor drawn to a larger
scale.
Fig. 6 shews, to an enlarged scale, the governor and gear for operating the gas
valve.
In Figs. Land 2 A is the cylinder provided with a piston B which is connected by
a rod C to the crankshaft D which rotates in suitable hearings in the bed and is pro-
vided with a fly-wheel in a manner now well understood. The cylinder A, as is usual
in engines of this class, is provided with a clearance space beyond the extreme inward
position of the piston, into which the gaseous contents of the cylinder may be com-
pressed. E represents the casing of a sliding cylindrical valve hereinafter more fully
described with reference to Figs. 3, 4, and 5. This valve is worked by a rod F which
derives its motion from a small crank on the spur wheel G which is caused to rotato
at half the speed of the engine by a pinion on the crank-shaft. FL is a rod that has n
motion in the direction of its length, imparted to it at such times (both in relation to
the travel of the piston and also in relation to the speed of the engine) as is necessary,
to operate a small gas valve J. This valve J may be an ordinary conical valve kept
on its seat by a spring and provided with a stem so that when the rod is moved in one
direction the valve opened and gas is allowed to pass into the cylinder.--The
rod H receives its motion from a reciprocating rod or piece K, (see Fig. 6) which is
attached by a small link to the governor sleeve L, and is so arranged that when the
governor rises, due to too great a speed of the engine, the piece K is move away
from the end of a lever K and is consequently not movel and gas is not admitted to
the engine cylinder. The lever K' is operated by an eccentric K*. It has been
previously explained that there exists a partial vacuum in the cylinder at the end of
the suction or charge stroke due to cutting off the air before the end of such stroke,
-so that when the valve J is operated gas is readily sucked into the cylinder and mixed
with the air therein.
The mixture of gas and air is then compressed on the instroke of the piston into
the aforesaid clearance space and fired by a hot tube M in a manner now well under-
stood. The working and exhaust strokes are then performed, and the engine is again
ready to draw in a fresh charge. N. is a small automatically lifting back pressure
valve that serves to keep the valve J free from the pressuro in the cylinder caused by
the explosion.
Having now described the general features of our improved engine we will refer to
the detail figures. 3. 4. and 5. illustrating the arrangement of the valves. In these
figures the same reference letters refer to the same parts as in Figs. 1 and 2 where
they occur.
O. is a plain cylindrical sliding valve moving freely in its casing and operated as
aforesaid at half the speed of the engine by a rod F. (see Figs. 1. and 2.). On its
under face are two cavities, separated by a bar P. In Fig. 4. the bar P. is shewn
closing the entrance to port Q which leads to the underside of the lifting valve R and
thence to the cylinder A. Qis a port, also in the lower face of the valve casing,
communicating with the air suction pipe S1, and Q2 is a port communicating with the
exhaust pipe S³.
At the end of every working stroke the valve R is mechanically lifted by means of
a bell crank lever T, and rod T¹, motion being obtained by means of an eccentric from
the toothed wheel G that revolves at half the speed of the engine. At this time the
valve O will be in such a position as to connect, by means of the right hand cavity on
its under side, the port Q leading to exhaust pipe S with the port Q leading to the
cylinder and the contents thereof are thus allowed to escape. At the end of the
exhaust stroke the bar 1 will be in the position shewn in Fig. 4, the valve moving to
the right hand, and immediately after, the further motion of the valve will by means

page_text: of the left hand cavity therein, places the port Q in communication with the port Q
and air suction pipe S'. Air will then be drawn into the cylinder for a predetermined
portion of the stroke, and until the further motion of the valve in the same direction
closes the port Q¹.
No more air can then enter the cylinder and that already therein
will be attenuated by the further motion of the piston. When the piston is near the
end of its outstroke, the gas valve J is open and gas allowed to pass into the rarefied
air contained in the cylinder. Gas continues to enter the cylinder on the return stroke
of the piston until atmospheric pressure is reached and compression begins, when
the small check valve N closes and further entrance of gas is prevented.
The valve R which is lifted at the commencement of the exhaust stroko, is kept
open during the air suction stroke, and closes before the port Q is again opened to the
pipe S by the return of the valve O, and remains closed during the compression and
working strokes and until the time for release of the waste gases in the cylinder again
arrives.
The valve R is not made fast to the spindle that lifts it, and which is actuated by
the lever T, but is loose therefrom, so that when gas is not taken into the cylinder and
no explosion takes place, the valve may lift automatically and act as a snifting valve,
as it will be seen there would otherwise be a partial vacuum in the cylinder, which
unless satisfied would cause a loss of work when the valve is opened.
As previously mentioned the vapour of petroleum or other hydro-carbon produced
in apparatus external to the engine may be used instead of gas.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed we declare that we are aware
that air and gas have been previously drawn into a cylinder separately or together
and in various ways, but what we claim is
1. The improved Motor engine to be worked with gas or vapour substantially as
hereinbefore described with reference to Figs. 1 and 2 of the drawings annexed.
2. In a motor engine to be worked with gas or vapour the arrangement and use
substantially in the manner and for the purpose specified of a sliding valve such as O
in conjunction with a lifting back pressure valve such as R (Figs. 3 4 and 5 of the
drawings annexed).
3. In a motor engine to be worked with gas or vapour the arrangement substantially
as described of a sliding valve, a back pressure valve such as R and gas inlet and
check valve such as J and N for the purposes specified.
Dated this 22nd day of March 1889
|Dated this 22nd day of March 1889
THOS. BROWETT.
W. Lloyd Wise,
Per F. J. B.,
46, Lincoln's Inn Fields, London, W.C.,
Agent for the Applicants.