Improvements in and relating to Gas and Oil Engines.
Year: 1897

page_text: Date of Application, 8th Mar., 1897-Accepted, 8th May, 1897
Improvements in and relating to Gas and Oil Engines.
I, MICHAEL CARMICHAEL DUNSMORE, of 4 Glebe Crescent, in the Town and
County of Stirling, Engineer, do hereby declare the nature of my invention and
in what manner the same is to be performed to be particularly described
and ascertained in and by the following statement in writing reference being made
to the accompanying drawings:-
This invention has reference to and comprises improvements in the construction
or arrangement and combination of the parts of gas engines, and in the construction
or arrangement of the firing appliances, some of the essentials of which improve-
ments are also applicable to oil engines of the same class, whereby a motor stroke
will be delivered at every revolution of the crank, with a rapid motion of the piston
at the point of greatest expansion, and a steady working of the engine be effected.
Also by arranging the ratio of the volume of the gases before compression to the
volume after expansion as about 1 to 1.7 or thereby a noiseless exhaust is effected,
and the power usually thrown to exhaust will be usefully utilized. Further by my
improvements the engine after having been started once, will by storing up a
portion of the energy be made self starting, and by utilization of the heat of the
exhaust gases the engine will be rendered to some extent regenerative.
In carrying my improvements as applied to a gas engine into practice gas and air
are drawn by the instroke of the piston into an annular space formed in front of
same where it is compressed by the outstroke and forced within storage tubes or the
like, where the mixture is heated by the exhaust gases from the cylinder and from
which it passes as required to the cylinder to be exploded, or burnt as it enters at
constant pressure, ignited by flame kept burning within the cylinder in which case
the back end of cylinder would not be water jacketted.
And in order that my said invention may be properly understood I have.
hereunto appended three sheets of explanatory drawings in which the same
reference letters are used to indicate the same or corresponding parts in all the.
figures where shown.
Figures 1, 2, and 3 on Sheet 1 are respectively a sectional elevation, a plan and
an end view of a horizontal gas engine constructed in accordance with my
improvements without showing the firing appliance, while
Figure 1 is a detail sectional elevation of the arrangement of the duplex air
and gas inlet valve taken on the line 1-1 in Figure 2.
Referring to these figures :-The cylinder A is formed as shown with the front
part A of a less diameter and having the ordinary jacketting space all round fitted
with inlet A3 and outlet A' shown in the drawings for circulation of water therein
to keep it cool. As shown the piston B is close ended and is formed with a trunk Br
of a diameter to fit the reduced front part A¹ of cylinder A and fitted with packing
rings B within which is jointed the connecting rod E to the crank E³, A' being an
orifice for lubricating the trunk.
By this construction an annular space a is formed around the trunk B' into
which mixed air and gas is drawn during the instroke of the piston from the duplex
inlet valve C through the port indicated at a¹ to be compressed during the outstroke
of the piston. During the instroke of the piston B the suction within the annular
space a causes the valve C' to rise so as to allow gas from the gas pipe C³ fitted
with a stop cock or valve C³ to pass through the ports C C and air from the
openings c in calculated proportions to be drawn within the annular compressing

page_text: space a through the passage c¹ and port a. On the outstroke of the piston the
mixture is compressed and passing back by the port a¹ and passage c¹ shuts the
valve C and raising the valve passes to the storing chamber by the pipe d.
As danger of over pressure within the storing chamber D might arise, a check or
governing piston valve is provided, regulated by a spring or a corrugated
diaphragm may be used instead, which moves when the pressure rises to a
predetermined amount and by its spindle acting on one arm of a bell crank lever
causes its other arm co to press upon the link c and so prevent the valve C' from
rising to admit gas and air. Instead of being allowed to work automatically the
valve may be opened and closed by a lever placed transversely under the
cylinder A and operated by a cam on the shaft G acting on one end, the other end
being connected to the valve spindle by a link. The gas and air passes from the
annular compressing space a by the pipe d, fitted with a two way cock or valve d¹
to be described, to the storing chamber D which is preferably as shown formed in
the base of the engine frame divided by a partition D' and fitted with an undulating
series of tubes d² through which the compressed mixed gases circulate on their way
to the cylinder by the continuation d³ of the undulating tubes and this pipe d³ is
provided with a non-return valve d' indicated in Figure 3 and stop cock d.
Though this storage chamber is shown formed in the base of the engine it may be
located otherwise and may have more than one series of tubes, or compartments.or
other arrangements may be used instead of tubes, or where it is not desired to use
the exhaust for heating a single storing vessel may be used.
A valve chest F is fitted on the cylinder and within which work the gas inlet
valve F as shown or which may be double ported and the exhaust valve F2
actuated as to be described from the shaft G which receives its motion direct from
the crank shaft of engine and makes one revolution for each revolution of same.
The compressed gas and air enter the cylinder by the port A after passing through
a series of closely set concentric rings F3 shown in plan to a slightly enlarged scale
by Figure 1 or it may be a wound spiral in one or more layers, or layers of wire
gauze, to prevent back firing in the event of premature ignition and the valve Fi
which is opened at the desired time by its spindle f¹ being acted on by the forked
end of the lever carried by the rocking shaft foscillating in an eyebearing and
actuated by the lever f the end of which is furnished with an antifriction roller
which is acted on by the tapered kicker G2 formed on the sleeve G' sliding on a
feather on the shaft G. The duration of opening of the valve being regulated
by the breadth of the kicker G2 at the point brought into contact with the
antifriction roller on the lever f the sleeve G' being acted on by the governor H
by means of any ordinary forked lever arrangement not shown in the drawings.
The end of the sleeve is left plain so that in event of the load going suddenly off
the engine the sleeve would be moved so far that the lever roller would run freely
on this plain part and the valve F1 would remain shut. A piston valve F' of larger
area than the valve F¹ or it might be a corrugated diaphragm is fitted on the valve
spindle to close the valve F when the pressure of the lever f² is removed.
A flap valve may be employed either in front or behind as indicated at d' Figure 3
the concentric rings to prevent the back flow of burnt gases, or the concentric rings
if made in two divisions the lower one loose on the spindle may act as a valve one
set of rings being made to coincide with the openings between the others so that
when forced together by an explosion the passage of gas would be stopped.
1
Instead of concentric rings a series of flat bars packed or bolted together and
resting in a.square seat within the valve chest and kept at a small distance apart
by projections as shown by Figure 1C may be used, or as in Figure 1" which shows
a section of part of the valve chest to an enlarged scale a series of flat rings F³
may be used packed one above the other and separated by small pins or
projections to allow the mixed gases to pass through from the outer annular
space F to the interior of the valve chest above the valve F1 otherwise the gas
may be led to the interior of the rings and through them to the exterior and down
through the valve which may be double ported.

page_text: The spent gases or exhaust pass from the cylinder by the port A through the
valve F and pipe F to the interior of the storing chamber D to heat the mixed
gases in the pipes d² finally passing out at D². The exhaust valve F' is opened at
the proper time by the forked end of the bell crank lever pressing the valve
spindle upwards when its other end furnished with an antifriction roller is acted
upon by the cam G³ on the shaft G. When so desired the exhaust pipe may have
an outlet to atmosphere fitted with stop cock or valve so that the whole or part of
the exhaust may be discharged without entering the storing chamber to heat the
gases. If desired air only may be compressed and stored and a separate gas
pump be used to supply compressed gas to mix with compressed and heated air
behind the piston.
The two way cock or valve d' may be opened to either of two passages or
ports d d the port d leading to the space above the valve c" and the port d to
the space below it, or in the position of the handle as shown it is closed to both.
By this arrangement the cock can be opened to port do when communication is
established between the annular pressure space a and the storage tubes d² so that
compressed gas and air can act on the piston to force it back and start the engine,
the force of the first stroke being also cushioned. When the engine has made one
revolution the cock is opened to port d when the compressed gases can pass to
storage tubes and the engine will be under full way.
Figures 4, 5 and 6 on Sheet 1 are respectively an elevation, a plan partly in
section and a sectional elevation of a gas igniting appliance which may be used
with the engine as described, Figure 6 being taken on the line 2-2 in Figure 5,
all the figures being to an enlarged scale, and this igniting appliance may be
screwed into the valve chest F at the part formed with the face plate F. In this
arrangement the igniter J is formed as a close chamber and is supplied through the
pipe J¹ fitted with a stop cock with the compressed mixture of gas and air from the
storage tubes d² which passes into the interior through the fine orifice J² a small
ball acting as a valve to prevent the gases at explosion passing down the pipe J¹.
A plunger K formed at its inner end as a valve working gas tight within a
cylinder Kformed on side of the igniting chamber J when moved outwards by
the action of the forked end of the bell crank lever L on the spindle K2 against
the power of the spring K³ opens the communication between the cylinder and the
igniting flame by the ports jj while at the same moment communication with the
atmosphere by the port J³ is closed. Within the igniter J mantles of wire gauze
as indicated at J* or equivalents may be fitted to retain heat sufficient to relight
the gas jet after such explosion, if necessary, or a small jet may be kept burning at
mouth of port J³. The movement of the plunger K is effected by means of the
angled projection M' on the lower arm of the bell crank lever M jointed to the end
of the rod m, and fitted with reaction spring m and stop me. This rod is jointed
to the lever, Figure 3 at m" and on this lever being released to allow the gas
valve F Figure 1 to close it draws up the rod m and bell crank lever M which
engages with the bell crank lever L and moves the plunger K outwards. When
the arm of the lever M comes against the stop M2 it is oscillated to release the
lever L when the plunger K is driven inwards by the force of the spring K³ to
close communication with the cylinder.
Figure 7 illustrates another form of trip gear for actuating the bell crank.
lever L by means of the bell crank lever m which engages with the angled end of
the arm of the lever L, the lower rod m³ being jointed to the lever at m.
Instead of this form of igniter ordinary igniting tubes may be used. Figures 8, 9,
and 10 on Sheet 2 illustrate three forms of an iguiter in which the ignition of the
gas is effected by the sudden compression of mixed gas and air effected by the quick
inward movement of a plunger which has been previously drawn out against the
action of a powerful spring one form of actuating mechanism being illustrated by
Figures 11, 11 and 12 on Sheet 3, and in some cases such as for high speeds the
igniters may be duplicated each coming into use alternately.
In Figure 8 the igniter is shown as fitted at right angles to the cylinder side and

page_text: consists of a plunger N the inner end of which may be formed of non conducting
material working within a small cylinder which may be water jacketted on
communication with the interior of the engine cylinder A by means of the small
passage or port n. A strong spiral spring N is fitted around the spindle N¹ and
secured between any suitable fixed abutment as merely indicated at N³ and the
collar N on the spindle N', N' being a washer to lessen the shock on the return
of the plunger. The plunger N being drawn outwards by suitable mechanism
the small cylinder becomes filled with mixed gas and air from the cylinder A
which is suddenly compressed by the force of the spring on the release of the
plunger and so has its temperature raised to a point sufficient to ignite the gases in
the cylinder.
Figure 9 shows a similar arrangement to that described but as fitted parallel to
the cylinder A and further provided with a spring loaded valve O to keep the port n
leading to the cylinder A closed until the moment of ignition, mixed gas and air
being supplied behind the plunger by a pipe indicated at a fitted with a non-return
valve from the storing tubes d2 Figure 1, or means may be employed to hold the
valve O open during the outstroke of plunger N to allow gases to enter from
cylinder A by port n.
Figure 10 shows an arrangement in which pure gas is drawn through the pipe P
and spring loaded non-return valve P' on the cutward movement of the plunger N
into the annular space then opened between the reduced part of plunger and wall
of its containing cylinder within which it is compressed on the return stroke of the
plunger and forced through the port p recess or port pl and port p² to the space p³
where it mixes with the air or poor gas drawn in through the pipe indicated at n
provided with a non-return valve. In this case also a spring loaded valve O is used
to close the passage n leading to the engine cylinder A until forced open by the
explosion of the mixed gases due to rise of temperature and pressure caused by the
sudden compression.
Figure 11 on Sheet 3 a small part of which is in section is a view of part of the
cylinder cover and valve chest and illustrates in detail one method of effecting
the igniting of the charge, by sudden compression of a small quantity of mixed
gases, in time unison with the cut off of the supply of gases to the cylinder,
Figure 11 being a side view of the end of the shaft G and the cams secured
thereon and Figure 12 a plan view of part of the arrangement.
In this arrangement the plunger spindle N¹ works in a guide between two fixed
rods connected by a crosshead which carry the reaction springs N2 and the
spindle N is fitted with a cross bar N° to bear on the inner ends of the springs N2.
A bell crank lever is fulcrumed on a bracket R one arm R¹ of which is provided
with an antifriction roller and being oscillated by the cam on the shaft G causes
the other arm R2, fitted with a reaction spring R³, by its forked end to move the
block S along the spindle N' on which it is placed loose. A lever or kicker S¹ is
mounted to oscillate on the top of the block: S so that when the block is moved
outwards by the bell crank lever R R2 the kicker S' by coming into contact with
the block S2 secured by a pin on the spindle N¹ causes the spindle to move out
until the kicker S' is raised by the roiler s being raised by the upward motion of
the lever T fulcrumed at T¹ as will be described when the reaction springs N2 will
force back the spindle and plunger and suddenly compress the gases to ignite them.
Should the supply of gases to the cylinder be cut off by the action of the governor
before the spindle N₁ is carried to the extremity of its stroke the kicker St is
lifted out of contact with the fixed block S2 by the rising of the lever 2 to cut off
the gas supply also raising the lever T by means of the link T2 so that the plunger
is released to ignite the gases in time unison with the cut off.
When the improvements are applied to engines ruuning at a high speed such as
upright engines driving dynamos with their connecting rods and cranks working
in oil within an enclosed space it is preferred to allow a small quantity of the air
compressed in the crank chamber by the down stroke to pass to the back of the
piston to clear out the exhaust and cool the cylinder. This is effected as shown in

page_text: Figure 13 by fitting the back of the piston B with a valve working on a valve
seat having a reaction spring 62 and counterbalancing weights 63 connected to..
end of valve spindl. by built steel springs 64, or it may be ordinary links. When
the piston makes an outstroke the air in front is compressed and on its instroke the
exhaust being opened the pressure behind becomes less than that of the air in front.
and a small quantity of which then passes through the valve to the back of the
piston, and in giving increased cushioning, necessary with high speed, cool air is..
compressed. As the piston completes its instroke air will be drawn into the space
in front through
an inlet valve fitted in the casing to replace that which passes.
through the piston.
These improvements may be applied to engines of the vertical type or to double
cylinder or tandem engines the valve actuating and other gearing being arranged!
accordingly for tandem engines a cylinder might be used having a dividing
partition about its centre through which would work a piston rod carrying two
pistons fitted with trunks as before described each delivering a motor stroke
alternately.
When applying these improvements to oil engines of the explosive or slow
combustion class the back cover of the cylinder would be modified by the addition
of a vaporizer and air alone would be compressed, stored and heated by the exhaust.
products of combustion and be led into the end of the cylinder behind the piston.
along with vaporized oil in due proportion.
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 what I
claim is:
First. The construction or arrangement and combination of the parts of gas and
oil engines all substantially as berein described.
Second. The construction or arrangement and combination of the parts of gas.
engines of the explosive class all substantially as herein described and illustrated
by the accompanying drawings.
Third. In gas and oil engines the compressing, storing, and heating of air all
substantially as herein described.
Fourth. In gas engines the compressing, storing, and heating of gas and air in.
measured proportions all substantially as and by the means berein-described and
illustrated by Figures 1, 2, and 3 of the accompanying drawings.
Fifth. In gas engines the construction and arrangements of the gas and air-
duplex inlet valve C and its governing appliance all substantially as herein
described and illustrated by Figures 14, 2, and 3 of the accompanying drawings.
Sixth. In gas engines of the explosive class the construction and arrangements.
of the parts of an igniting appliance and actuating devices all substantially as.
herein described and illustrated by Figures 4 to 7 of the accompanying drawings.
Seventh. In gas engines of the explosive class the appliances for igniting the.
charge by sudden compression of a portion of mixed gases all substantially as
herein described and illustrated by Figures 8, 9, and 10 of the accompanying.
drawings.
Eighth. In gas engines of the explosive class the appliances for actuating
igniting devices of the class claimed in Claim Seven all substantially as herein.
described and illustrated by Figures 11, 114, and 12 of the accompanying
drawings.
Ninth. The fitting of a valve in the piston end of vertical gas engines of the
class referred to constructed and arranged all substantially as and for the purposes
herein described and illustrated by Figure 13 of the accompanying drawings.
Tenth. In gas and oil engines of the explosive class the construption and use of
the sleeve C¹ and kicker G2 mounted on the shaft G and actuated by a governor
for regulating the admission of mixed gas and air or air alone to the cylinder.
all substantially as herein described and illustrated by Figures 2 and 3 of the.
accompanying drawings.

page_text: Eleventh. In gas engines the use for the prevention of back firing of the mixed
gases of the appliances all substantially as herein described and illustrated at F³
Figure 1, and Figures 1B, 1° and 1".
Dated the cal "
1007
W. R. M. THOMSON & Co.,
96 Buchanan Street, Glasgow, Agents.