Inflammable Gases or Vapours and Atmospheric an
Year: 1888

page_text: Date of Application, 4th July, 1888
Complete Specification Left, 4th Apr., 1889
Complete Specification Accepted, 4th May, 1889
Inflammable Gases or Vapours and Atmospheric an
1, WILLIAM THOMAS ROWDEN, of Lenzie in the County of Dumbarton, North
Britain, Professor of Applied Mechanics in the Glasgow & West of Scotland
Technical College, do hereby declare the nature of this invention to be as
follows:-
My said invention is an improved motor which depends, like other motors
commonly called gas engines or oil engines, upon the explosion or rapid inflammation
of mixtures of gas or vapours of volatile liquids and atmospheric air, in a cylinder
fitted with pistons; and my improvement consists in the arrangement of cranks,
connecting rods, and pistons in such a way that when the motor is working at full
power, or at less than full power within such limits as the reduction of power is
allowed by throttling the gus, it gives one impulse for each revolution of the fly
wheel, clears out of the cylinder, if desired, the whole of the products of combustion,
and allows of such amcants of compression and expansion as may be desired.
In constructing my motor I make use of a modified form of the arrangement of
cranks and connecting link described by me in my Provisional Specification
No. 5774, 18th April 1888. I use a cylinder open at both ends and fitted with two
pistons. That nearer the cranks, which I call the front piston, is attached by a
connecting rod to a single cheek crank or its equivalent in the ordinary way.
The other, or back piston, is attached to a connecting rod which returns from the
back along the outside of the cylinder, on that side of the cylinder remote from the
aforementioned shaft and is connected to a crank on the extremity of another shaft
the direction of which is parallel to the direction of the former but not quite in the
same line, the two cranks being face to face. The two crank-pins I connect in the
following manner :-to the second mentioned I rigidly fix an arm in a plane parallel
to that in which the crank revolves, but not necessarily parallel to the crank itself.
At the end of this arm I put a pin like a crank pin and I connect this pin by means
of a link or connecting rod to the crank pin of the other crank which is made long
enough for this purpose.

page_text: By those arrangements I can put the two cranks in the relative positions which
best suit the object in viow as well as modify their relativo angular velocities by
the excentricity of the two shafts. The relative lengths of the two cranks determine
the relative amounts of travel of the two pistons, whilst the oxcentricity of the two
shafts as well as the difference in lengths of the connecting rods modify the naturo
of their motions.
By suitable adjustments of the relative dimensions and positions of the various
parts of the mechanisms above described I am able to cause the pistons to recede
from and approach each other twice in one revolution of the shafts.
The charge is taken in through suitable ports during one recession, comprossed
during the following approach and then fired, allowed to expand during the
following recession, the products of combustion expelled during the following
approach, and thus the cycle is completed.
The fly whool may be attached to either shaft but preferably it is attached to that
connected with the back piston.

page_text: Inflammable Gases or Vapours and Atmospheric Air.
I, WILLIAM THOMAS ROWDEN, of Lenzie in the County of Dumbartonshire,
North Britain, Professor of Applied Mechanics in the Glasgow and West of Scotland
Technical College 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 :-
My said invention is an improved motor which, like other motors commonly called
gas-engines, depends for its energy upon the heat produced by the explosion or
rapid inflammation of mixtures of combustible gases or vapours of combustible liquids
and atmospheric air in a cylinder fitted with pistons and my improvement consists
in the combination of shafts, cranks, connecting rods, and pistons in such a manner
that when the motor is working at full power or at powers less than full power
within the limits possible by throttling the supply of combustible material it gives for
each revolution of the fly wheel the following cycle: (1) Draws in the explosive charge,
(2) Compresses it and fires, (3) Expands the ignited charge beyond its original
volume, expels the spent charge, either completely or as far as thought desirable
when designing the engine. To obtain this cycle I make use of a modified form of
the combination of cranks and connecting link described in my specifications
No. 5774, A.D. 1888. I use a cylinder open at both ends fitted with two pistons as
shown in dotted lines in the drawing. That nearer the cranks, which I shall call the front
piston, is attached by a connecting rod R₁, in the usual way, to the pin E of a single
cheek crank or disc. The other, or back piston, is attached to a connecting rod R₂,
which returns along the outside of the cylinder to the crank pin B between two crank
cheeks A B and BC. These cheeks are not parallel but at an angle as shown
by A. B. (., in the elevation. The crank thus formed is carried by a shaft A which
has its axis parallel to, but not in the same straight line as the axis of shaft D
which carries the crank D E. The prolonged crank pin E is connected by a
connecting link EC to the pin C as shown in dotted line EC in elevation.
Such an arrangement causes the shafts A and D to have different angular
velocities at different parts of their revolution. Either shaft D or A may be arranged
for carrying the main fly wheel, and that selected will revolve with uniform angular
velocity as in ordinary engines, whilst the other will have velocities varying in
different parts of its revolution. In this way, the two pistons will have different
relative velocities at different times, the differences being intensified by the unequal
lengths of their connecting rods R, and R..
Thus by selecting suitable dimensions for the various parts and suitable relative
positions for the two axes of the shafts 1 am able to obtain the cycle above
mentioned.
•
The action of my motor is as follows: Suppose the main fly wheel attached to
the shaft A and the cranks, piston rods, connecting link, and shafts to be of the

page_text: dimensions and in the positions shown in the drawings, and revolution to ho in the
direction indicated by the arrow. The compressed clurge is now just brought to the
ignition tube I which is kept hot by a burner attached to the seat S, as usual. The
crunk of the front piston is now revolving with a higher angular velocity than that
of the back piston, and from this combined with its shorter connecting rod and from
the crank B of the back piston not having quite reached its dead centro, the front piston
moves away from the back piston and so allows the ignited gases to expand and do
work. By the time that about three fourths of the stroke of the front piston has been
completed the back piston begins to gain on the front piston which then opens the
port leading to the exhaust valve which is attached to the sent S,, but not shown in
the drawing. This valve may be either automatic or worked by a cam K, through
rod Land the necessary levers.
The crank ED has its velocity now much reduced and this, assisted again by its
shorter connecting rod, allows the back piston to continue to gain on the front piston
and so to expel the spent charge. On their return, the back piston for a time still
moves faster than the front piston and at the propor point the back piston uncovers
the port P and a charge of the combustible mixture is drawn into the increasing
space between the pistons through a suitable valve attached to the seat S, this valve
also being either automatic or moved by the cam K, through the rods MN and NO
combined with the necessary levers.
The front piston closes this admission port as soon as the maximum volume between
the pistons is nitained, then gaining on the other piston comprosses the charge ready
for the next cycle.
The ratios of the volumes between the two pistons at the ends of the four parts of
the cycle as enumerated above depend upon the ratios of the lengths of the different
parts and the relative positions of the axes of the shafts. With the comparative
lengths and relative positions shown in the drawings, the following are the approxi-
mate relative numbers :-