Improvements in Gas Motor Engines.
Year: 1893

page_text: Date of Application, 19th Dec., 1893
Complete Specification Left, 19th Oct., 1894-Accepted, 24th Nov.,
1894
PROVISIONAL SPECIFICATION.
Improvements in Gas Motor Engines.
I, JOHN HENRY HAMILTON of Sandiacre in the County of Derby, Engineer
do hereby declare the nature of this invention to be as follows:-
In my Complete Specification 601500 I describe a form of engine having. & four
stroke cycle and in which the products of combustion are expelled from the
combustion chamber by a charge of air.
My present improvements embody the application of this principle to an engine
of the four stroke type but having two or more motor cylinders and also relate to
improvements in valve and governor gear for this engine but also applicable to
other types of engine.
In carrying my improvements into effect I place the two motor cylinders tandem
wise the air cylinder being in front of one of them.
The front motor piston has an enlarged end to fit this air cylinder (which also
forms a guide for the front end of the piston) the size of the piston being sufficient
to allow of two side rods being attached to it these rods passing backwards through
bushes in the cover of the annular space and alongside the front motor cylinder
these side rods being attached by their back ends to a crosshead secured to or cast
on the back motor piston.
A sufficient space is allowed between the cylinders to allow of the reciprocation
of this crosshead which is preferably provided with guiding slippers which work
on planed ways on the bottom stay piece which connects the front and back motor
cylinders.
The top stay piece is removable so as to allow of the back motor piston being
taken out; and this stay piece forms a portion of the air passage for conducting
the air scavenging charge to the back motor cylinder.
I now proceed to describe the arrangement for distributing the scavenging air,
the valve gear of the motor cylinders being arranged so that an explosion shall take
place in each at alternate revolutions thus giving an explosion at each forward
stroke when working full power.
The large air or guide cylinder has two ports one being at the back end and
communicating directly with the air passage which conveys the air to the admission
valves of both cylinders. These valves are preferably placed above the combustion
chambers of the cylinders the exhaust valves being below.
The other port in the air cylinder is placed further along so as to be covered
and uncovered by the piston which is of sufficient length to keep the port covered
when it is full back.
This port communicates directly with the air supply from the atmosphere but
the other above mentioned port only communicates with the air supply through an
automatic inlet valve.
The action is as follows.
At the commencement of an outstroke air is drawn into one of the motor cylinders
and into the air cylinder through the back port and the automatic inlet valve.
When the piston of the air cylinder uncovers the front port the air passes directly
into this cylinder through that port, but still through the automatic inlet valve to
the motor cylinder..
On the return stroke which is the exhaust stroke of the other motor cylinder part
of the air drawn into the air cylinder is first discharged through the front port thus
passing back to the atmosphere and when the piston closes this port the remaining

page_text: air is slightly compressed and forced through the back port into and through the
combustion chamber of the motor cylinder which is making its exhaust stroke thus
expelling the products of combustion and replacing them.
The same action takes place during the next revolution but the operations are
reversed in the two motor cylinders that is the series of operations which have
taken place in the front motor cylinder now take place in the back and rice versa.
The admission and gas valves may be arranged as described in my Complete
Specification No. 4189 and the charge of gas may either be reduced or cut off
altogether this being effected by varying the lift of the admission valve. This
admission valve may be operated by a steel push piece engaging with notches in a
plate attached to a lever the said lever being moved by a cam on the lay shaft
as usual.
If the notches in the plate gradually increase in depth the lift of the gas valve
will be varied to the same extent and if a deep notch be formed at each end of the
plate the gas valve will not be lifted when the push piece engages with these.
The push pieces may be pivotted to the levers which open the valves or to the
valves and have jointed to them the ends of a rod or lever to the middle of which
the governor is connected.
Thus if the governor rises or falls and one of the push pieces is engaged with
the notched plate and the other free the joint of the former with one end of the
rod or lever becomes a fixed fulcrum and the governor acting at the centre of this
rod or lever moves the free end carrying with it the push piece thus admitting,
cutting out or varying the gas charge.
A pair of stops for each push piece prevent them from going too far either way.
I prefer to form these stops on a weighted lever (or on two levers which move
together being rigidly connected) and the stops for each push piece may take
the form of slots in the levers through which the rod or lever described above
passes.
These rigidly connected stop levers may be counterweighted and the counter-
weight supported on a fixed stop so that when the governor falls the rod comes
first to the ends of the slots and when the governor speed has decreased considerably
the counterweight or counterweights are raised and the governor drops to its
lowest position in which position the push pieces are opposite deep notches in the
notched plates and the gas valve is not opened. This forms a safety appliance for
stopping the engine should the governor driving gear break but will not come into
action with any ordinary fall in speed due to an increased load.
Instead of one rod or lever for connecting the two push pieces each may be
connected through the intervention of rods levers and spindles to the ends of a
lever to the middle or some other intermediate part of which the governor is
connected.
This lever may work between stops as described above in the case of the lever
connected directly to the push pieces. I may attach a weight or spring to one of
the push pieces or to one of the levers connected therewith the object being to
prevent that push piece cutting out a charge till the speed shall have risen by some
definite amount above the speed at which the other push piece cuts out.
The principle of this governor gear is applicable also to four cylinder engines
or to engines having four admission valves."
For this purpose each pair of valves may have their push pieces connected to
the ends of a lever as above described which levers I will call secondary levers the
governor being connected to the middle of the same but in this case not directly
but through the intervention of another lever which I will call the primary lever
and to the middle of which the governor is connected and which in turn has each
end connected either directly or through crank arms and spindles to the middle of
each of the secondary levers.
If three of these push pieces be engaged with notches and the fourth free, one
of the secondary levers will become fixed, and one end of the other, the other end
being free and the end of the primary lever which is connected to the former will

page_text: be fixed and that connected to the latter free, thus if the governor rises the free
push piece will be moved the extent of the motion being four times the motion of
the centre of the primary lever.
A series of three weights or springs may act on three of the push pieces or on
the connections to them in such a way that the four cylinders may be cut out in
succession by a progressive increase of speed and inversely that they shall come
into action in succession by a progressive diminution of speed.
The weights or springs I prefer to make readily interchangeable so that if the
engine works often with a light load the weights or springs may be changed and
thus the burden of the work will not always fall on the same cylinder or
cylinders.
Instead of weights or springs acting always on one side of the centre of the
lever I may use a tumbler weight or spring which if one push piece be in a position
to give a full charge of gas and the other in a position to cut out a charge will
tend to maintain the parts in these positions or if the relative positions of the push
pieces be reversed it will still tend to keep them in those positions.
For operating the igniting valve I propose to use the same lever as that which
operates the admission valve. The igniting valve may be connected to this lever
by a rod sliding through a nut or eye piece on the lever and having a spring
interposed hetween this nut and the ignition valve, and a stop on the other side of
the nut.
When the admission valve is opened this spring is compressed pressing the
ignition valve on its seat and it remains closed thus till the lever moves back
sufficiently far to bring the nut or eye piece against the stop on the rod and any
further back movement allows the ignition valve to open under the action of another
spring which is weaker than the first named spring.
Thus the admission valve may be opened by a forward movement. of the lever,
and the ignition valve by a backward movement.
As it may be necessary to alter the time of opening of the ignition valve without
affecting the other valves I form the cam which operates the lever as described
above in two parts divided by a plane at right angles to the axis of the shaft
which carries it and I make the roller which runs on this cam wide enough to bear
on both parts. The one part is made of the right contour for giving motion to
the admission valve and the other of that required for the ignition valve. The
former is secured to the shaft and the latter may be clamped to it by a screw
or screws so as to have sufficient angular adjustment.
The herein before described method of governing are applicable generally to all
multiple cylinder engines and the arrangement for operating both the admission
and timing valves by means of one lever are applicable generally to engines with
single cylinders as well.
Dated this 18th day of December 1893.
5
COMPLETE SPECIFICATION.
Improvements in Gas Motor Engines.
1, JOHN HENRY HAMILTON of Sandiacre in the County of Derby, 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 :-
In my Complete Specification No. 60150 I describe a form of engine having a
4 stroke cycle and in which the products of combustion are expelled from the
0 combustion chamber by a charge of air.
My present invention embodies the application of this principle to an engine with

page_text: .
two or more cylinders and also relates to the governing of such or other multiple
cylinder engines and I now proceed to describe my improvements with reference
to the accompanying drawings in which Fig. 1 is a longitudinal sectional elevation,
Fig. 2 a sectional plan Figs. 3, 4, 5 & 6 views of my improved governing and
valve operating arrangements.
The cylinders A and B are motor cylinders placed tandemwise and each provided
with an admission valve C a gas valve D and an exhaust valve E and an igniting
apparatus of the usual type.
The piston F of the cylinder A is enlarged at its front end sufficiently to allow
of the attachment of the side rods H H which pass backwards alongside the
cylinder A, and which are secured at their rear ends to a crosshead secured to or to
lugs cast on the piston of the back cylinder the said crosshead or lugs being
preferably supported by planed guides I on the bottom stay piece which connects
the front and back motor cylinders.
A removable top stay K forms an air passage to convey air to the back
cylinder.
I now proceed to describe the arrangements for distributing the scavenging
air, the valve gear being so arranged that explosions will occur alternately in the
motor cylinders.
The enlarged front end of the piston F slides in the large cylinder. L. In this
cylinder are two ports or rather one port P at the back end and a series of ports Q
near the middle, the bars between these ports prevent the piston rings from springing
out in passing the ports.
The ports Q lead directly from the atmosphere through the space M which is
in free communication with it, but between the port P & the atmosphere is an
automatic non return valve or series of valves N. This valve may be similar to
that described in my Specification No. 6015. The port P is in free communication
with the passage R which conveys the air to the motor cylinders.
The ports are placed so as to be covered and uncovered by the large end of
the piston F and the latter is made long enough to keep the ports covered when
it is full back.
The action of this arrangement is as follows-
On the commencement of a forward stroke, air is drawn through the valve N
from the space M and part of this air passes into that motor cylinder which
happens to be making its suction stroke while the remainder passes into the
cylinder L. After the piston passes the ports Q the air has a direct passage from
the atmosphere to both these cylinders for the remainder of the stroke. On the
return stroke the admission valve of the motor cylinder being closed the charge is
compressed in the usual manner while during the first part of this return stroke the
air is being expelled from the cylinder L through the ports Q, but after those
ports are covered by the piston the air is slightly compressed and then forced
through the admission valve of the other motor cylinder in which the piston is
making its exhaust stroke.
The admission & exhaust valves being held open allow the air to pass through
the combustion chamber and sweep out the products of combustion therefrom. The
exhaust valve is preferably held open till after the crank has passed the centre
thus giving time for the air to be discharged from the cylinder L. During the
next revolution the same series of operations takes place except that the back
motor cylinder now takes the place of the front one in this series and
" vice versa.
"
By placing the ports Q further back or forward the amount of air which is passed
into the combustion chambers of the motor may be changed. The air is thus
discharged at the right time viz. during the latter part of an exhaust stroke.
Figs. 3 & 4 Sheet 2. illustrates the mode of operation of my improved governor
gear, which is generally applicable to two cylinder engines.
In this, p&p represent push pieces actuating the gas 'admission valves 'and
receiving their motions from levers Z & Z¹ operated by a cam.

page_text: The rod or tube ✪ receives rotational movement from the governor which thus
by means of the arm U raises or lowers the lever T that is raises it when the speed
increases and lowers it when the speed falls.
This lever T has pivotted to it the rods S & S¹ which connect it with the push
pieces&p. The movement of the lever is limited preferably by means of stops.
formed by slots in levers X and Y which are rigidly connected together and move
about a fixed fulcrum f. A weight g resting on a fixed support E keeps the levers
in the normal position shewn.
The action of this gear is as follows, supposing the cam to be in such a position
that one of the push pieces say p is engaged with one of the notches in the piece r.
This push piece thus becomes fixed and the pivot k becomes the fulcrum of the .
lever T and thus any movement of the governor takes effect on the free push
piece p. Thus it may raise the latter so that at the next forward movement of the
lever Z it will engage with a deep notch and the gas valve will not be opened.
If the governor continues to rise the same action will take place on the other
side and the push piece p will be raised and thus a charge ent out in the
2nd cylinder.
A light weight W may be used to make the governor cut out a charge in one
cylinder in advance of the other. If this weight be shifted occasionally from one
rod to the other the cylinders may thus be made to share the load more equally
and the whole burden of the work will not be thrown on one cylinder when working
at less than full power.
If the notches in the pieces & be made of varying depths the lift of the
gas valve will be varied according to the position of the governor and thus the
strength of the charge will also be varied.
The bottom notches may be made so deep that the gas valves shall not be lifted
when the push pieces engage with them, the lower stops which limit the movement
of the lever T being so placed that the push pieces shall only engage with these.
notches after depressing the ends of the levers X & Y and raising the counter-
weight g off the stop e, thus ensuring that the gas supply shall be cut off only after
a considerable reduction in the speed of the governor.
Figs. 3 & 5 also illustrate my improvements whereby the ignition timing valve
is operated from the admission valve lever thus simplifying the valve gear. In these
the end of the timing valve spindle 1 is attached to a rod which passes through
the spring 2 and block 3. The latter has pins or projecting lugs to fit in slots
in the lever Z.
The action is as follows.
On the opening of the admission and gas valves by the movement of the
lever Z¹ the timing valve is first pressed on its seat and thereafter the spring 2 is
compressed.
On the return motion this spring re-expands the block 3 sliding back on the
rod but not sufficiently so to come in contact with the nut 4.
The parts remaining in this position during the interval between the closing of
the admission valve and the end of the compression stroke the roller operating the
lever Z running on a circular part of the cam concentric with the cam shaft.
Towards the end of the compression stroke a drop on the cam comes round and
allows the lever Z' to move still further back bringing the block 3 against the nut 4
and allowing the spring 5 aided by the compression in the cylinder to open the
timing valve. Figs. 5 & 6 shew the arrangement for controlling the point of
ignition independently of the other part of the valve motion.
The roller 15 is made broad enough to cover two cams 7 & 8. The cam 7 being
fixed on the shaft and 8 clamped to 7 by means of a set screw 10. The cam 7
is of the correct contour for giving movement to the admission valve and 8 that
for giving motion to the ignition, timing valve. It will be seen that when the
drop 9 comes round to the roller the timing valve will be opened & that by
varying the angular position of the cam 8 the point of ignition may be controlled
without affecting the rest of the valve motion.

page_text: I have not shewn the improvements illustrated in Figs. 3-6 applied to the
particular type of engine described with reference to Figs. 1 & 2 as these improve-
ments are generally applicable to two cylinder engines and their application
to the above type of engine can be readily understood from the foregoing
description.
Nor have I described with a drawing the application of the governor gear
to 4 cylinder engines as that case is a simple extension of that of the two cylinder
engines.
Thus it will be seen that instead of the governor being connected to the lever T
by a rigid attachment it might be connected in the same way to the centre of
another lever, one end of the latter being connected to the centre of the lever T
and the other end to the centre of a similar lever similarly situated with respect
to two more cylinders and controlling the push pieces operating their admission
valves in a similar way.
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
1. A tandem gas engine having a piston with an enlarged end working in a
cylinder provided with two ports or series of ports substantially as illustrated
and described with reference to Figures 1 and 2 of the accompanying drawings.
2. Governor gear for two cylinder engines consisting essentially of a lever to the
ends of which the bit and miss gas valve operating pieces are connected, the
governor being connected to the middle or other intermediate point of this lever
substantially as illustrated and described.
3. The method of operating the ignition timing valve from the admission valve
lever substantially as illustrated and described with reference to Figs. 3, 4, 5 & 6
of the accompanying drawings.
Deted this 17th day of October 1894.