Improvements in Gas Motor Engines.
Year: 1890

page_text: Date of Application, 10th Apr., 1890
Complete Specification Left, 10th Feb., 1891-Accepted, 14th Mar., 1891
PROVISIONAL SPECIFICATION.
Improvements in Gas Motor Engines.
I, FREDERICK WILLIAM LANCHESTER, of 13, Bedford Row, in the County of
Middlesex, Engineer, do hereby declare the nature of this invention to be as
follows:-
My invention for improvements in gas motor engines relates to engines of that
class in which inflammable gas or vapour together with a certain proportion of
atmospheric air is introduced into the working cylinder and then or after com-
pression exploded to increase their pressure to propel the piston during the
working stroke: and has for its object to provide improved means for starting
the said engines.
This invention consists substantially in introducing into the working cylinder
while the piston is stationary a charge of inflammable gas or vapour which forces
out a portion of the air contained therein and mixes with the remaining air until
an explosive mixture is formed, and in providing means whereby the formation of
the said mixture is indicated and, on cutting off the supply of inflammable gas,
or vapour, exploded to start the engine; and whereby when the engine is running
explosive charges in the cylinder at atmospheric pressure are ignited at the
commencement of the working stroke: and when required in compression engines,
after starting the engine from rest as above described, either in keeping the
pressure of the explosive charges in the cylinder approximately that of the
atmosphere until the engine has attained sufficient speed to overcome the resistance
of compression so that they can be exploded at the commencement of the working
stroke by my device; or, in engines fitted with the ordinary tube igniter, in
providing means whereby low pressure charges can be ignited by the said tube
igniter, the said low pressure of the charges being produced by a relief cam as
ordinarily used in some compression engines for reducing the amount of compression
until a sufficient speed has been attained to overcome the resistance of compression.
In a gas engine provided with a starter constructed according to my invention,
the compression chamber is fitted with a tube terminating in an expanding nozzle
opening to an external flame. This tube can be permanently closed by a cock and
contains a valve which normally remains open by its own weight but will auto-
matically close by the sudden generation of pressure in the cylinder.
In order to start an engine fitted with my improved device for starting, the
engine is placed in such a position that its crank is somewhat over the in-centre of
the working stroke, the external flame of the starter is lighted, and the gas or
inflammable vapour
is turned on to the working cylinder through a suitable nozzle
or nozzles. The gas or vapour first displaces a portion of the air which passes ont
through the nozzle of the starter and then a gradually increasing proportion of gas
or vapour passes out with the air until it burns with a characteristic roar in the
expanding nozzle, when the auxiliary gas supply is cut off and the flame passes
back into the cylinder and burns or explodes the charge to increase its pressure to
start the engine. The automatic valve in the starter closes immediately on the
explosion. The cock of the starter is then turned to put it out of action and the
engine continues to work in the ordinary manner.
A relief cam, which keeps the exhaust port open during more or less of the
compressing stroke (as is frequently used to facilitate hand starting) may be used
in compression engines to enable the impulse given by the initial charge to over-
come with certainty the back pressure of the compression.
In another arrangement a relief cam is arranged to keep the exhaust port of the
cylinder open until the piston has completed its compressing stroke. The engine

page_text: is started as described above and after exhausting the products of the first explosion
draws in a fresh charge which on the return or compressing stroke is forced out
through the exhaust port and through the nozzle of starter. As soon as the piston
commences its working stroke, the explosive mixture ceases to pass through the
nozzle of the starter and the flame passes back into the cylinder. A series of
explosions may be obtained in this manner. When the speed of the engine is
sufficient to overcome the resistance of compression, the auxiliary cam and starter
are thrown out of action and the engine works in the ordinary manner.
In order to admit of a relief cam of the ordinary construction being employed in
engines fitted with the ordinary tube igniter a chamber of sufficient capacity is
arranged so that it can be put into communication with the tube of the igniter by
means of a stop cock. In this arrangement, and if also provided with my starter,
after the first explosion the starter is shut off, the auxiliary chamber is put into
communication with the igniter and the relief cam being in action the engine will
work in the ordinary manner with a reduced compression until a sufficient speed is
attained, when the relief cam and auxiliary chamber are put out of action. If the
engine is not provided with my starter, the relief cam and auxiliary chamber are
put in action and the engine turned by hand until an explosion occurs when the
engine will continue to work as in the above described modification.
Instead of the relief cam, a relief lever opposite the exhaust lever may be
operated by the ordinary cam and act on the exhaust lever for the same purpose.
Dated this 10th-day of April 1899.
WHEATLEY & MACKENZIE,
40, Chancery Lane, London, W.C., Agents.
COMPLETE SPECIFICATION.
Improvements in Gas Motor Engines.
1, FREDERICK WILLIAM LANCHESTER, of 13, Bedford Row, in the County of
Middlesex, 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 :—
This invention for improvements in gas motor engines relates to engines of that
class in which inflammable gas or vapour together with a certain proportion of
atmospheric air is introduced into the working cylinder, and then or after compres
sion exploded to increase their pressure to propel the piston during the working
stroke and has for its object to provide improved means for starting the said
engines.
This invention consists substantially in introducing into the working cylinder
while the piston is stationary inflammable gas or vapour which forces out a portion
of the air contained therein and mixes with the remaining air until an explosive
mixture is formed, and in providing means whereby on cutting off or reducing the
supply of inflammable gas or vapour, the said mixture is exploded to start the
engine and whereby when the engine is running explosive charges in the cylinder
at atmospheric pressure are ignited at the commencement of the working strokes :
and when required in compression engines, after starting the engine from rest as
above described in keeping the pressure of the explosive charges in the cylinder
approximately that of the atmosphere until the engine has attained sufficient speed
to overcome the resistance of compression so that they can be exploded at the
commencement of the working stroke by this device.
In a gas engine of the Otto type provided with a starter constructed according
to this invention the compression chamber is fitted with an attachment communi-
cating with the said chamber and terminating in an expanding nozzle opening to an
external flame. This attachment can be permanently closed by a cock, and
contains a valve which normally remains open by its own weight but will
automatically close by the sudden generation of pressure in the cylinder.

page_text: Carving
Fig. 7 is a similar cross section showing the application of a pump for introducing
the charge of gas or inflammable vapour which may be arranged to deliver the
required volume at a single stroke.
Fig. 8. shows the character of the indicator diagrams produced in starting an
engine of the Otto cycle modified as described above.
Figs. 9 and 10 are sections showing suitable arrangements of the starter when
the ignition is effected by means of an incandescent tube.
The end of the cylinder or compression chamber 1 is fitted with an attachment
consisting of a valve box 2, of a stop cock 3 through which communication is
made between the cylinder and valve box 2, of a valve 4 which normally remains
open by its own weight but is automatically closed by pressure in the engine
cylinder, and of a nozzle 5 which is connected to the valve box 2 and opens to an
external flame 6. The nozzle 5 is preferably conical expanding towards the
direction of discharge. The external flame 6 can be adjusted with reference to the
nozzle 5 by means of the thumb screw 7 and is supplied with gas by means of a
tube connected to the nipple 8. A stop cock 9 serves to regulate or extinguish the
flame 6.
The compression chamber 1 is also fitted with a suitable nozzle 10 by

page_text: means of which gas can be admitted to the cylinder through the supply cock 11.
The gas so admitted may be forced in by the ordinary pressure in the gas supply
pipes as illustrated in the cross section Fig. 6.or it may be supplied by means of a
hand pump 12 as shown in Fig. 7.
In order to start an engine fitted with the starter it is placed, or it may have
been stopped at its previous working, in such position that its crank is somewhat
over the in-centre of the working stroke; the external flame 6 of the starter is
lighted and the gas or inflammable vapour is turned on to the working cylinder
through the nozzle 10. The pressure in the gas pipes causes the gas to flow into
the cylinder and displace a portion of the air it contains through the nozzle 5, but
the entering jet mixes with the remaining air as indicated at Fig. 6. by the arrows
and so produces an explosive mixture, part of which after a time finds its way
through the nozzle 5; the external flame 6 then ignites it and the jet burns at the
nozzle 5 through the external flame into the atmosphere, increasing in richness of
gas or vapour till explosive mixture is formed. The gas supply cock 11 is then
shut off and the flame passes back into the cylinder and ignites or explodes the
charge to increase its pressure to start the engine. The automatic valve 4 in the
starter closes immediately on the explosion of the charge and then the cock 3 is
turned to put it out of action, when the engine continues to work in the ordinary
manner. The diagram given by this explosion is indicated at Fig. 8 by the
lines a aa a and in some cases where the friction of the engine is proportionally
small, the single impulse so given is sufficient to start the engine even against the
compression. An incandescent body or shower of electric sparks or other convenient
means may be used in lieu of the flame.
Instead of having a separate means of introducing the inflammable vapour for
starting the engine, the supply valves may be opened and the engine turned in the
proper direction by hand to draw in combustible mixture and then slightly turned
back in the reverse direction to force a portion of the said mixture through the
starter nozzle where it is ignited, the flame travelling back and exploding the
mixture as described above to start the engine.
When a number of low pressure explosions are required to get up speed, a
cam 13 is arranged on the second motion shaft in such manner that when placed in
gear, it holds open the exhaust valve 14 during the whole compression stroke of
the engine. This cam 13 is placed in gear before obtaining the first explosion as
hereinbefore described, and when the engine moves under its influence the modified
action of the subsequent strokes is as follows:-The burned gases resulting from
the first explosion are discharged on the next instroke, then the exhaust valve
closes and on the outstroke a charge of gas and air is drawn into the cylinder; a
large proportion of this volume of explosive mixture is discharged on the following
instroke which in ordinary circumstances would be the compression stroke. So
long as the exhaust valve 14 is held open by the special cam 13 the pressure
remains near that of the external atmosphere but enough back pressure exists to
cause the mixture to flow through the starter and burn from the nozzle 5 it being
ignited at the external flame 6. When the piston arrives at the in-end of the stroke
and the exhaust valve closes, the pressure rapidly falls and the flame passes back
to the compression space at the end of the cylinder and explodes the mixture to
give an additional impulse to the engine. A. diagram similar to bbbb Fig. 8. is
thus produced and the piston moves forward on its working stroke. So long as the
starting cam 13 is in gear and the starter cock 3 is open, the engine continues in
motion and a low pressure impulse is given at every second revolution. When the
speed has become sufficiently great to allow of the compression, the cock
closed and the starting cam 13 is put out of gear in any usual manner; the engine
then acts by its ordinary igniting arrangement with compression.
is
Instead of supplying gas direct from the gas supply pipes by its ordinary
pressure, the hand pump 12 is sometimes used to force in a charge of gas through
the check valve 15 by the nozzle 10 to the cylinder 1. The action is precisely
similar to that hereinbefore described and the explosion occurs when the hand

page_text: pump piston has terminated its discharging stroke. The check valve 15 prevents
the effect of the explosion from reaching the gas pump. The charge of the gas
pump and the direction of the jet from the nozzle 10 is so arranged that explosive
mixture speedily finds its way to the starter nozzle 5.
In all arrangements ignition passes back immediately the velocity of propagation
of the flame exceeds the velocity of the mixture.
The valve 4 may be held open by a spring instead of its own weight and the
position may then be varied by placing it at the side or under the cylinder instead
of above it.
The object of the valve 4. is to prevent undue loss of pressure on the explosion
taking place, the grooves 25 being of such an area as will not interfere with
ignition.
In Figs. 9 & 10 the gases issuing from the cylinder are ignited by an incandescent
tube 26 and the flame passes back to the cylinder immediately the flow is sufficiently
reduced and the resulting explosion closes the valve whether the tube be between
it and the cylinder or outside the valve. The issuing gases may be ignited by the
electric spark or other means. The relative areas of the nozzles may be such that
the flame instead of being caused to strike back by reduction of the rate of flow
strikes back on the mixture becoming sufficiently rich. In this latter arrangement
an automatic valve somewhat similar to the valve 4. is placed upon the gas supply
pipes and closes automatically when the explosion occurs.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that which I
claim is :-
1. The herein described method of starting a gas motor engine, by introducing
into the cylinder gas or explosive mixture, allowing a portion of the contents of the
cylinder to escape through an igniting nozzle, and after external ignition takes
place causing the velocity of outflow to fall short of the velocity of propagation
of flame so that ignition passes back to the cylinder and explodes its contents to
propel the piston.
2. The herein described method of starting a gas motor engine working with
compressed charges by keeping an exhaust port open during the ordinary com-
pressing strokes, thus allowing a portion of the contents of the cylinder to escape,
and igniting the remaining portion in the manner set forth in the preceding claim,
and continuing this mode of working until the engine acquires sufficient momentum
to effect the compression of the charges.
3. A gas motor engine starting apparatus consisting of a nozzle opening from
the cylinder to an external flame or other igniter, the said nozzle containing a
check valve which remains open except when subjected to a predetermined
pressure within the cylinder arranged and operating substantially as and for the
purposes hercin set forth and illustrated by the accompanying drawings.
Dated this 10th day of February 1891
WHEATLEY & MACKENZIE,
40, Chancery Lane, London, Agents.