Improvements in Motors Worked by Gas or other Combustible Bodies.
Year: 1888

page_text: Date of Application, 18th Apr., 1888
Complete Specification Left, 17th Jan., 1889
Complete Specification Accepted, 23rd Feb., 1889
PROVISIONAL SPECIFICATION.
Improvements in Motors Worked by Gas or other Combustible
Bodies.
I, WILLIAM THOMAS ROWDEN, of Lenzie, in the County of Dumbarton, North
Britain, Professor of Applied Mechanics in the Glasgow and West of Scotland
Technical College, do hereby declare the nature of this Invention to be as
follows, that is to say :-
My said Invention has for its object to obtain increased efficiency and other
advantages in motors which depend for their energy upon heat due to the explosion
or rapid combustion of combustible bodies and air in cylinders fitted with pistons,
whether such bodies be gases or vapors generated apart from the motors themselves,
or vapor or spray formed from a volatile líquid introduced into the motors.
My Invention may be applied to a gas motor of the Otto type in which each motor
cylinder with its piston is single acting and in which there is an ignition in each
motor cylinder at every alternate revolution of the crank shaft. My improvements
may also be modified to suit gas motors of other types.
My Invention comprises improved modes of operation and apparatus or mechanism
for obtaining the saine. I cause the piston to have a comparatively high velocity
after the inflammation of the gaseous mixture, so as amongst other results, to shorten
the duration of the contact of hot expanding gases with the colder cylinder, and
thereby lessen the loss of work due to the conduction of heat through the cylinder
walls. By a comparatively lessened velocity of the piston at an earlier stage I secure
sufficient time for the complete inflammation of the mixture and thereby lessen the
The same arrangements give
loss that would be caused by late inflammation.
comparatively increased time for the compression of the explosive charge conducing
to the more complete intermixture of the air and gas or combustible body, and
rendering the uniform and complete spreading of the flaine more certain. The several
advantages indicated are obtainable without altering the average speed of the motor;
whilst the force of the impulses is applied and distributed in a better manner than in
many existing gas motors.

page_text: In carrying out my Invention according to one modification, I connect the motor
piston in the ordinary way, to a single-cheek crank, or to a crank pin on a disk on a
shaft;
but instead of placing the fly wheel on the same shaft I place it on a separate
shaft which is parallel to the first shaft but with its axis at a certain distance from
that of the first shaft. The fly wheel shaft has on it a crank or a crank pin on a disk
placed contiguously to the same parts of the first shaft, and the crank pins of the two
shafts are connected by a link, the crank pin of the first shaft being made long enough
for such link as well as for the connecting rod jointed to the piston. With these
arrangements, assuming the angular motion of the flywheel shaft to be uniform that
of the first shaft will vary so as to be quicker at one part of the revolution and slower
at another. The throws or radii of the two cranks, the length of the connecting link,
and the relative positions of the two shafts may be variously proportioned in different
cases; but I believe satisfactory results will be obtained with an arrangement in
which the two cranks are of equal throw or radius, the length of the link equal to the
radius of the cranks, and the distance apart of the shafts equal to half the radius of
the cranks, the flywheel shaft being in a plane inclined about 75 degrees from the
plane containing the axes of the cylinder and first shaft. If the first crank moves
through the upper half of its course with the out stroke of the piston, the flywheel
shaft should be placed lower than the first shaft, the angle of the plane containing
it and the first shaft being measured from the other plane in the lower outer
quadrant.
According to another modification I fix on the fly wheel shaft a face plate or disk
made with a radial groove in which there is fitted to slide a block having fixed in it a
pin on which is jointed the connecting rod from the motor piston. The sliding block
is, by means of a crank, eccentric, cam, or other suitable device constrained to move
in a path which is not concentric with the flywheel shaft.
The desired varying angular motion of the first shaft can also be obtained by
gearing it to the flywheel shaft with eccentric toothed wheels or toothed wheels of
varying radius.
Dated this Seventeenth day of Anril 1988
EDMUND HUNT,
Applicant's Agent.

page_text: COMPLETE SPECIFICATION.
Improvements in Motors Worked by Gas or other Combustible
Bodies.
I 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 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 has for its object firstly to obtain increased efficiency as heat
engines of motors which depend for their energy upon the heat due to the explosion
or rapid combustion of mixtures of combustible bodies and air in cylinders fitted with
pistons whether such bodies be supplied as gases or as liquids to be converted into
vapours or spray in the motors themselves, and secondly to obtain a better distribution
of the work, so as to lessen the jerking effect of the impulsive action of the explosion
on the fly wheel and machines driven by the motor.
My invention may be applied to any such motor in which the impulses act in one
direction in a cylinder on a piston connected with the main driving shaft and fly wheel
of the motor by a connecting rod and crank, or the equivalent of a crank, namely a
disc and excentric pin.
My invention comprises an improved combination of apparatus or mechanisms for
carrying the work of the expanding gases to the main or driving shaft of the motor.
It enables me with a given number of revolutions per minute of this shaft to decrease
the time during which work is being done in the cylinder by the hot expanding gases,
and thus to decrease the loss due to the heat passing into the sides of the comparatively
cold cylinder without materially altering the time allowed for the inflammation or
ignition of the combustible mixture at or near the commencement of the working
out-stroke of the piston. It also enables me to intercept for a time any desired portion
of the work done by the expanding gases at that part of the motion or travel of the
piston when most power is in the usual arrangement being communicated to the
flywheel and machines driven by the motor, and to restore that work later in the cycle
when less or no work is being done by the gases in the cylinder.
In carrying out my invention I connect the motor piston, which is not shown in
the drawing, by a connecting rod R, with a crank pin P, in a single cheek crank or
in a disc D on a shaft S₁. The crank-pin P, is made long enough to connect
therewith another connecting rod or link R, which at its other end is connected to the
crank pin P, of another single cheek crank or disc on the main or driving shaft S..
The two shafts S, and S, are in parallel lines but not in the same straight line.
The first named disc D or the crank instead thereof, and which would preferably be
a balanced crank, I make of such dimensions as to secure the necessary
" inertia'
for taking up the desired portion of the work of the expanding gases at the proper
time.
دو

page_text: With the combination thus made, assuming the angular velocity of the main or fly.
wheel shaft S, to be uniform, or nearly so, the angular velocity of the shaft S₁ and its
crank or disc will continuously vary during a revolution, attaining a maximum at one
position and a minimum at another. The ratio between the maximum and minimum
velocities depend upon the relation existing between the two crank lengths, or radii,
the length of the rod R, connecting the two crank pins P₁ and P, and the distance
apart of the centre lines of the two shafts.
The positions in the circle formed by P₁ at which the pin will attain its maximum
and minimum velocities depend upon the position which the axis of S₂ occupies with
respect to the axis of S₁.
These lengths and positions may be varied to suit different requirements, but for
the purpose of explaining the working of my invention I will assume the two crank
lengths, or radii, and the length of the link connecting the two crank pins to be the
same, the distance between the axis of S, and the axis produced of S, to be about
one-half these lengths and the position of Se as shown in the elevational drawing
where the positions of the disc D and the shaft S₁ are shown in dotted lines, (the
drawing of these parts being omitted there for the sake of clearness) revolution taking
place in direction of arrows A, A.
At the commencement of the outstroke of the piston, the shaft S₁ will have an
angular velocity rather less than that of the shaft S, and its fly wheel, but this velocity
will then be increasing and will continue so till it attains a maximum velocity when
the crank pin P, is at about the position Mx, after which it will decrease to a minimum
velocity near Mm. The time taken for the outstroke will be only about two thirds of
the time which would be taken were the main fly wheel on shaft S₁ as in ordinary
motors.
The greatest increase per unit of time of the angular velocity of S, and its crank or
disc, that is to say the greatest angular acceleration, will occur when the parts are in
about the positions shown in the drawings, and then according to well known laws of
mechanics the heavy crank or disc D will absorb the greatest amount of work.
This position is made to coincide approximately with that when the greatest amount
of work per unit of time is being done by the expanding gases.
After the positions shown in the drawings the acceleration diminishes (though
the velocity still increases) and less and less work is absorbed till the position of
maximum velocity Ma is reached, after which the velocity diminishes till the point
of minimum velocity Mm is reached.
During this part of the revolution, that is from M to Mm, the work which was
taken up by the heavy crank or dise will be restored-minus, of course, the loss caused
by friction.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what I
claim is:
In a motor in which power is obtained from explosions or rapid combustions of
combustible bodies and air, the combination of two shafts not in the same straight line
connected by cranks or discs and crank-pins and connecting rods, to the motor piston,
for the purposes set forth and in a manner substantially as described.
Dated this 16th day of January 1889.
WILLIAM T. ROWDEN.