Improvements in Motors worked with Heated Compressed Air, in parts applicable to Internal Combustion Engines.
Year: 1897

page_text: Date of Application, 3rd Apr., 1897
Complete Specification Left, 1st Jan., 1898-Accepted, 2nd Apr., 1898
PROVISIONAL SPECIFICATION.
Improvements in Motors worked with Heated Compressed Air, in
parts applicable to Internal Combustion Engines.
We, JOHN EDWARD THORNTON, of Rokeby, Oldfield Road, Altrincham, in the
County of Chester, Manufacturer, and JAMES POLLARD LEA, of 7, Southbank
Renshaw Street, Altrincham, in the County of Chester, Engineer, do hereby declare
the nature of this invention to be as follows:-
We will describe in general terms an engine which includes the features of
this invention.
A cylinder, truly bored, is properly fitted with a piston which moves to and
fro in it under control of a crank. A valve of the ordinary mushroom type is
conveniently placed and actuated by suitable means from the engine shaft.
Towards the end of the outward stroke the said valve is opened and any
pressure existing in the cylinder thus released. Immediately afterwards the
piston uncovers suitable openings in the cylinder wall through which fresh air
forcibly enters and sweeps the more heated air before it, past the still open valve
into the atmosphere, so that the cylinder is left full of comparatively cold air.
Both the valve and openings in the cylinder wall are closed soon after the
commencement of the inward stroke of the piston during which stroke the fresh
charge of air is compressed, advantageously, into a prolongation of the main
bore of the cylinder. Into this prolongation of the cylinder, which forms a
compression space, a light disc or piston is properly fitted so as to be capable of
sliding to and fro in it. To assist in effecting this movement a suitable rod is
attached to the said disc and passes through a suitably packed opening in the
back cover of the cylinder. A passage communicates from the space in the
cylinder between the main piston and the disc aforesaid, to the space also in
the cylinder between the aforesaid disc and the back cover of the cylinder.
This passage is so formed and arranged that considerable part or parts of it
can be very highly heated and oil, gas, coke, or even powdered coal or other
convenient or suitable fuel may be used and applied externally for this purpose.
Such highly heated part or parts are arranged advantageously, so as to be easily
renewable when necessary. When the piston approaches the end of its inward
stroke and the charge of air is considerably compressed, the aforesaid disc is by
suitable means moved to and fro and thus the greater part of the compressed air
is caused to traverse and re-traverse the aforesaid highly heated passages and its
pressure in consequence is considerably increased. The heated passages are,
advantageously, so constructed that whilst the capacity is comparatively small
the surfaces presented internally to the air may be relatively large; and further
the construction may be such as to permit of an impinging, or a series of
impinging, action greatly conducive to the absorption of heat by the currents
of compressed air.
To control the speed or the power of the engine the to and fro movement of
the disc may be modified in extent so that a varying amount (according to
requirement) of the compressed air may be heated and a correspondingly varying

page_text: pressure result. And in conjunction with this, an approximately corresponding
amount of heat may be imparted to the heater passages.
To start such an engine the aforesaid heater passages are first raised to a suit-
able temperature. Then as the heat required is already in existence and stored
in the walls of such passages it cannot fail to be given up to the compressed air
currents and therefore the power is developed immediately and with absolute
certainty. If the engine stands habitually with its piston at the full extent of
its outward stroke then any means of giving the engine shaft a moderately quick
movement for half a revolution or a little over would suffice to start the engine
in either direction, the engine continuing to run in the direction in which such
movement was given to it. As the engine may be standing for a more or less
lengthened period ready to start at any moment it may be arranged that only
the requisite amount of heat necessary to make up for radiation and other losses
may be imparted to the heater at such times.
Owing to the high temperature of the compressed air it may be desirable to
keep the cylinder cool with a water jacket in a manner well known. But only
sufficient water to surround the heated parts requiring to be cooled need be used,
and the water jacket may contain a space unfilled except by vapour given off
from the heated water. Such vapour may have access to a number of tubes
presenting a very considerable surface to the atmosphere and in them the vapour
may be condensed and drain back to the water jacket. The water jacket and
vapour spaces in free connection with each other may be quite separate from the
atmosphere and hermetically sealed. It would be advantageous that such enclosed
space should not contain any air and the pressure in such space may be less than
that of the outside atmosphere.
L
d law of il 1807
improvements in
parts applicable to Internal Combustion Engines.
We, JOHN EDWARD THORNTON, of Rokeby, Oldfield Road, Altrincham, in the
County of Chester, Manufacturer, and JAMES POLLARD LEA, of Worsley Mills,
Hulme, Manchester, in the County of Lancaster, Engineer, late of 7, Southbank,
Renshaw Street, Altrincham, in the County of Chester, 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 relates to motors in which the motive power or force is obtained
from the expansion of air or other gas or gases by heat and is designed to provide
a compact and reliable motor of this class.
The heat may be imparted to the said air gas or gases first, by transmission
through the walls of suitable placed and formed passages the primary source of
heat being outside the motor cylinder.
Second, by mixing a suitable combustible such as gas oil or spirit with the
air then igniting same with the resultant evolution of heat and the formation
of various gases and products of combustion in the cylinder which themselves

page_text: Fig. 4. Dectiona
Referring to Figs. 1 to 3, in the cylinder A is fitted at one end a trunk piston B
capable of moving to and fro therein the greater part of its length and at the
other end an auxiliary disc or piston C with only a short travel or movement.
The cylinder A is accurately bored and is provided at or near the centre with
an annular chamber or recess D forming a port for the inlet of cold air to the
interior of the cylinder. The lower end is connected to an air chamber E commu-
nicating by a port or passage F through the chamber D with the interior of the
cylinder and provided with an air inlet valve G through which the necessary
supply of fresh air is admitted. The upper end of the cylinder A is provided
with air passages h leading to a heater H and with an exhaust valve K and
exhaust port or passage k.
To the main piston B is fitted, pivoted on the pin b, an oscillating_connecting
rod which connects the piston B with the crank L. The crank L is placed
inside the air chamber E and the crank shaft L' projects through the walls of
the air chamber at either side rotating in journals which are packed to prevent
the escape of air.
The heater H which is in communication with the interior of the cylinder A
through the air passages h is constructed with two concentric cylinders h¹ h
the air passages passing through the interior of the inner cylinder h¹ and around
the exterior of it and through the interior of the outer one h¹¹. A supply pipe M
supplies gas, oil or vapour to a burner which causes a flame to impinge upon the
exterior of the outer cylinder h¹¹. A combustion chamber m is formed around
the cylinder by a protecting cover M¹ lined with asbestos or other non-con-
ducting material. Instead of gas or oil solid fuel may be burned around the
heating cylinder h¹¹.
The inlet valve G opens to admit fresh air when the pressure in the air
chamber E is reduced below the external atmospheric pressure by the return
stroke of the piston B.
The exhaust valve K is controlled by a cam N on one side the crank shaft L'
operating on a pivoted lever n connected to the valve spindle k¹ by a connecting
rod n¹. The valve is closed by the spring k¹¹.
The auxiliary piston C in the upper end of the cylinder is operated and caused
to move to and fro therein by a cam 0 on the crank shaft L¹ operating on a pivoted
lever P which is connected with a second pivoted lever P¹ by the connecting rod p.
The pivoted lever P¹ rests against the end of the piston rod C¹ and moves the
piston C in one direction the internal pressure moving it back in the reverse
direction and the spring c maintains it in position against the cylinder cover.
The action of the motor would not differ materially if the chamber E were
connected with the casing of valve K and the annular port D with the exhaust
pipe. In such case the direction of the air entering cylinder would be reversed.
The cylinder is kept cool by a jacket R filled with water.
The operation of the motor when running is as follows:-
The piston B being in the position shown in the drawing at the end of its stroke

page_text: the chamber or port D is uncovered and the cylinder filled with a fresh charge
of air. On the return stroke of the piston B it travels to the position indicated
by the dotted line y-y leaving the air passage h uncovered and compresses the
air in the cylinder and also draws a fresh charge of air into the chamber E through
the inlet valve G. The movement of the crank which returns the piston E also
rotates the cam N releasing the exhaust valve K which is closed by the spring kl.
When the piston B approaches the position indicated by the dotted line y-y the
cam O operates the levers P and P and moves the piston C towards the piston B.
The pressure in the cylinder operating on the area of the piston rod C returns it
back again to the cylinder cover and the spring c retains it in that position. This
movement of the piston C forces the compressed air through the air passages h
to the heater H to the other side of the piston C and back again into the cylinder
between the two pistons the air being thus heated and its pressure increased. The
increased force or pressure is exerted upon the piston B to drive it back and give
motion to the crank L and crank shaft L'. This forward stroke of the piston B
compresses the fresh charge of air in the chamber E and the motion of the cam N
opens the exhaust valve K a little before the port or passage F is uncovered, thus
the heated air is allowed to escape and is all forced out through the exhaust
passage by the inrush of the fresh charge of compressed air through the port F
and annular passage or chamber D. The cycle of operations then recommences
and continues during the running of the motor.
To control the speed or the power of the engine, the to and fro movement of
the piston C may be modified in extent, so that a varying amount (according to
requirements) of the compressed air may be heated and a correspondingly varying
pressure result.
And in conjunction with this an approximately corresponding
amount of heat may be imparted to the heater H by decreasing the power of the
external burner.
In applying the invention to internal combustion engines a nozzle is connected
to the heater H from which a jet of oil is delivered into the internal tube h¹ by
means of a small pump suitably actuated by the engine. The jet of oil is injected
into the heater at the time the secondary piston is causing the compressed air
to traverse the said passages as previously described. The oil is vaporized imme-
diately by the heat of the compressed air aided by the hot walls of the passages h¹,
and being delivered into the current of air a well formed and mixed charge is
obtained. When the movement of the air ceases that part of the combustible
mixture which is in the tube has time to ignite thus firing the whole charge
with consequent increase of pressure. In this case after the heater H has been
heated externally to start the engine the heat of the passages would be maintained
by the external heat of the charges and during the running of the engine no
external lamp would be needed.
To start the motor the aforesaid heater H is first raised to a suitable tempera-
ture. Then as the heat required is already in existence and stored in the walls
of the passages, it cannot fail to be given up to the compressed air currents, and
therefore the power is developed immediately and with absolute certainty. If
the motor stands habitually with its piston at the full extent of its outward stroke
(as shown in the drawings) then any means of giving the crank shaft L¹ a
moderately quick movement for half a revolution or a little over would suffice
to start the motor in either direction the motor continuing to run in the direction
in which such movement was given to it. As the motor may be standing for a
more or less lengthened period ready to start at any moment, it may be arranged
that only the requisite amount of heat necessary to make up for radiation and
other losses may be imparted to the heater H at such times.
In the modification shown in Fig. 4 the cylinder A in which the piston B works
is fitted at the end with an auxiliary piston C and is provided at or near the centre
with an exhaust air port or passage D forming an annular chamber which is
uncovered by the piston when it reaches the end of its outward stroke. In this
form of motor at the end of the cylinder A in which the auxiliary piston is placed

page_text: it is fitted with two air passages h leading to a heater H formed of concentric
tubes which are heated by a suitable gas, oil or other burner.
To the air passage h is fitted an air inlet valve G which opens when the internal
pressure is reduced below that of the atmosphere and is closed by a spring g.
The rod C¹ of the auxiliary piston C is enclosed in an airtight casing forming
a cylinder or chamber T communicating with the lower end of the cylinder Å
by a passage or tube F¹. This passage is provided with an air valve G¹ by which
air is admitted thereto should the pressure therein at any time become reduced
below that of the atmosphere.
Instead of two air passages h in the cylinder through which the charge is passed
from one side of the auxiliary piston C to the other a passage and valve may be
made in the piston and the lower passage h lead to an igniter.
The cylinder A is jacketed with water R to keep it cool.
The operation of the motor when running is as follows:-
The piston B being in the position shown in the drawing and ready for the
return stroke, the air at the back of the piston will have been compressed into
the passage F and chamber T above the piston rod C¹ and forced the auxiliary
piston C down or to traverse the cylinder A. This movement of the auxiliary
piston C forces the spent air or products of combustion out through the exhaust
port D and draws in through the inlet air valve G a fresh supply of air or com-
bustible mixture into the end of the cylinder above the auxiliary piston C. On
the return stroke of the piston B the exhaust port D is covered and during this
stroke the pressure on the top of the piston rod C₁ is relieved. The returning
piston B then raises with it the piston C until it again passes the lower air
passage h, compressing the air in the cylinder above it. The pressure of the
compressed air at this point acts upon both sides of the piston C and as the area
of the under side of the piston is greater than that of the upper side of the piston
to the extent of the diameter of the piston rod the greater pressure exerted
thereon returns the piston C to the position shown in the drawing forcing the
fresh air charge through the heater where it is heated and the expansive force
acting upon the piston B drives it back thus operating the motor. The cycle
of operations then recommences and continues during the running of the motor.
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 what we
claim is:-
1. A motor operated by hot air or other gases constructed with a main piston
working to and fro in the cylinder and an auxiliary piston by which the com-
pressed charge is passed through a heater or other passages in the cylinder walls
substantially as and for the purpose described.
2. A motor operated by heated air or other gases fitted with air inlet and
exhaust passages, and provided with air passages connecting one part of the
cylinder with another, a main piston working to and fro in the cylinder an
auxiliary piston which forces the compressed charge through the said air passages,
a chamber into which the fresh air is drawn and in which it is compressed by
the return stroke of the piston, and a passage leading from air chamber to the
interior of the cylinder substantially as described.
3. A motor having two pistons constructed with an airtight casing surrounding
the rod of the auxiliary piston communicating with the back of the cylinder in
which the air is compressed by the forward stroke of the piston to operate the
auxiliary piston substantially as described.
4. In a hot air motor an auxiliary piston for forcing the charge through the
heater or from one side of the piston to the other operated by the compression
of air in the cylinder at the back of the main piston substantially as described
with reference to Fig. 4.

page_text: 5. A hot air motor constructed and arranged substantially as described and
shown with reference either to Figs. 1 to 3 or Fig. 4 of the drawings.
Dated this 30th day of December 1897.
WM. P. THOMPSON & Co.,
6, Bank Street, Manchester, Patent Agents.