IMPROVEMENTS IN GAS MOTOR ENGINES
Year: 1880

page_text: LETTERS PATENT to Francis William Crossloy, of Manchester, in the County
of Lancaster, for an Invention of "IMPROVEMENTS IN GAS MOTOR ENGINES."
PROVISIONAL SPECIFICATION left by the said Francis William Crossley at
the Office of the Commissioners of Patents on the 21st October 1880.
FRANCIS WILLIAM CROSSLEY, of Manchester, in the County of Lancaster.
"IMPROVEMENTS IN GAS MOTOR ENGINES."
My Invention relates to gas motor engines of the kinds described in the
Specification of C. D. Abel's Patent, dated 17th May 1876, No. 2081. In these engines
a charge of combustible gaseous mixture is drawn into the cylinder, compressed
therein, and ignited, and the products of combustion are discharged, but not wholly,
a portion of them remaining in a space which, in some of these engines, is provided
in the cylinder, beyond the range of the piston's stroke, to contain the compressed
charge. For the purpose of clearing more or less this spaco from the residuary
products of combustion, I provide a pump worked from the engine shaft, preferably
at half the speed, and so time its strokes that while the products of combustion are
being expelled from the cylinder it discharges into the space of the cylinder above
referred to a gascous mixture to displace therefrom the residuary products of
combustion. The gaseous mixture thus introduced into the cylinder is preferably
so diluted with air that it will not burn unless it be compressed. In some cases
instead of introducing a gaseous mixture I introduce air alone. In order more
effectually to clear away the residuary products of combustion the space in the
cylinder may be parted off by a partition having a mouth opening into the cylinder,
and may be divided by partitions arranged to form a continuous zig-zag passage
through it. The pump, instead of discharging directly into the cylinder space, is
preferably made to discharge into a receptacle communicating with the cylinder by
a passage provided with a valve that is opened at the proper times for admission
to the cylinder. The opening of this valve may be controlled by a governor or by
regulating apparatus, such as is hereinafter described. This receptacle may also be
in communication with the body of the pump, so that the pump draws in only such

page_text: fresh supply as is required to make up for the charge that may be sent into the
cylinder.
For the purpose of enabling an attendant to regulate the power and speed of the
engine I provide a drum, geared to the engine shaft, so as to be driven at a
relatively slow speed. On this drum there are cam projections arranged in sets
around it, each set presenting a different number of projections on the circumference
of the drum. A lever connected to the gas supply valve has on it a roller which
can be moved by the attendant longitudinally along the drum so as to be acted on
by any desired set of the cam projections. Each of the cam projections is so placed
on the drum as to cause the opening of the gas supply valve at the time suited to
a working stroke of the engine, and as the number of strokes worked with a supply
of gas during each revolution of the drum depends upon the number of cam
projections that are thus made to act on the valve, the attendant by shifting the
roller so that it is acted on by a set presenting a greater or less number of these
can vary, as desired, the power or speed of the engine.
When the slide cover is secured by bolts and nuts the slide is apt to become
tightened when it expands under the influence of heat. In order to avoid this I
secure the slide cover indirectly by friction in the following manner :-Pressing the
cover against the slide with such moderate pressure as will hold the slide against
the facing without preventing it from moving freely, tighten up transverse
setting screws, wedges, or other frictional appliances provided in the slide cover, or
fixed to the cylinder, so that they bear against the sides of studs, lugs, or other
convenient projections arranged on the cover or on the cylinder, and I thus give
the cover sufficient frictional hold to maintain the tightness of the slide, whilst in
case of expansion it can yield sufficiently to permit the slide still to work freely.
When the slide cover is thus secured the arrangement sometimes employed for
temporarily increasing its pressure so as to hold the slide in close contact with the
cylinder facing may be dispensed with.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Francis William Crossley in the Great Seal Patent Office on the
21st April 1881.
FRANCIS WILLIAM CROSSLEY, of Manchester, in the County of Lancaster.
"IMPROVEMENTS IN GAS-MOTOR ENGINES."
My Invention relates to gas motor engines of a kind described in the Specification
of C. D. Abel's Patent, dated 17th May 1876, No. 2081. In the kind of engine
referred to a charge of combustible gaseous mixture is drawn into the cylinder,
compressed therein, and ignited, and the products of combustion are discharged, but
not wholly, a portion of them remaining in a space which is provided in the
cylinder beyond the range of the piston's stroke to contain the compressed charge.
When gas of a highly imflammable character, such as coal gas, is used as the
combustible ingredient of the gascous mixture, the presence of these residuary
products of combustion does not interfere with the thorough combustion of the
charge, their action differing little from that which would result from the presence
of an equivalent volume of air; but when gas of a less inflammable character, such,
for instance, as carbonic oxide, is employed, it is of advantage to substitute air for
the residuary products of combustion in the space of the cylinder. In order to
effect this substitution I provide a pump worked from the engine shaft, preferably
at half the speed, and so time its strokes that while the products of combustion are
being expelled from the cylinder it discharges air into the space of the cylinder
above referred to so as to displace therefrom the residuary products of combustion,
and in order more effectually to clear these away, the space of the cylinder may
have partitions arranged to form a tortuous passage through it. The pump is
preferably made with a considerable clearance space communicating with the
cylinder by a passage provided with a valve that is opened at the proper times for
admitting the air to the cylinder.
For the purpose of enabling an attendant to regulate the power and speed of the
engine I provide a drum geared to the engine shaft so as to be driven at a relatively
slow speed. On this drum there are cam projections arranged in sets around it,
each set presenting a different number of projections on the circumference of the
drum. A lever connected to the gas supply valve has on it a roller which can bo
arranged by the attendant so as to be acted on by any desired set of the cam
projections, either by moving the roller or the drum longitudinally. Each of the
cam projections is so placed on the drum as to cause the opening of the gas supply
valve at the time suited to a working stroke of the engine, and as the number of
strokes worked with a supply of gas during each revolution of the drum depends
on the number of cam projections that are thus made to act on the valve, the
attendant by shifting the roller or drum so that the valve is acted on by a set
presenting a greater or less number of these can vary, as desired, the power or speed
of the engine.
The accompanying Drawings represent a gas motor engine according to my
Invention. Fig. 1 is a side view, and Fig. 2 is a plan with part of the cylinder shewn
in section. The other Figures, drawn to an enlarged scale, represent parts of the
engine, that is to say, Fig. 3 is a vertical section of the air pump on the line Z, Z,
of Fig. 2; Fig. 4 is a part plan of the air pump shewing the eccentric for working
it, and the crank and cam for working the valves; Fig. 5 is a transverse section
on X, X, through the cylinder and slide; Fig. 6 is an end view shewing the
regulating apparatus, and Figs. 7, 8, and 9 are sections of the regulating drum.
The crank shaft A works by gearing B a countershaft C at half the speed; on this
countershaft is fixed a cam disc D having a crank pin working by a connecting
rod E the slide F, which has suitable passages and governs suitable ports for the

page_text: admission to the cylinder G of the charge of combustible mixture of gas and air
and for the ignition of the charge. The slide with its passages and the ports are
for this purpose constructed and arranged as is usual in gas motor engines of the
kind to which my improvements relate. In the construction shewn the air supplied
by a passage a and the gas by a passage governed by a valve hereafter referred
to pass together by the cavity f of the slide F to the inlet part i of the cylinder,
when the cavity f is open to that port. When the slide moves to cover the port
the charge that had been drawn into the cylinder by an outstroke of the piston is
retained therein, while it with the other contents of the cylinder is compressed by
the next instroke of the piston, and when the slide moving farther brings the
ignition passage c opposite to the port i the charge is ignited in the usual way.
So far the construction does not materially differ from gas motor engines of the kind
referred to. I will now describe the modifications in the construction and action of
the engine which form the subject of my present Invention. On the counter shaft C
is fixed an eccentric H which works the piston of a single acting air compressing
pump I; this pump is made with a considerable space below the piston, which at
the upstroke of the piston receives a supply of air through a suction valve K. At
the down stroke of the piston the air below it is compressed and a portion of it
Hows by a pipe L to a port of the cylinder G, which port is governed by a valve,
as will be presently explained. Another port e permits discharge from the cylinder
G when a valve in the exhaust pipe is opened. The cylinder has in it a partition G
which causes the air on its way from 7 to e to take a tortuous course so as more
effectually to clear out the residuary products of combustion. On the disc D is a
cam D¹ which acts on a roller on one arm of a bellerank lever M, the other arm of
which is connected by a rod m to two levers N and O which act as tappets against
the ends of the stems of valves that are caused by springs n, o, to close respectively
the passages and e; these passages are opened only when their valves are raised
in opposition to the springs by the tappet levers N, O, and these are so adjusted
by screws N¹, O¹, and moved by the cam D¹, that the exhaust valve in the passage
is opened before the air valve in l, but both valves close simultaneously. As stated
above the supply of gas to the passage g is regulated by a valve, and this valve is
arranged and worked so that it may give full supply of gas at each charging stroke
of the piston when the full power of the engine is required, or that it may
altogether cut off the gas supply during one, two, or more charging strokes when
the power of the engine has to be moderated. The desired operation of the valve
is effected in the following manner:-On the crank shaft A is a worm gearing
with a worm wheel on a spindle P, which is thus driven at much less speed than
the engine shaft. As shown in the Drawings the gearing is such that the engine
shaft Å makes 10 revolutions for each single revolution of the spindle P. On the
spindle a drum Q is fitted to slide longitudinally with a feather, causing it to
revolve with the spindle, and it can be slid to and fro by a hand lever E' provided
with a catch to take into one or other of the notches of a quadrant. On the drum Q
are fixed side by side sets, each presenting a number of cam projections, some of
which are shewn at Figs. 7, 8, and 9, each set of these, counted round the circum-
ference of the drum, being different in number; thus in the first section of the drum
there is only one projection, in the second there are two, and so on, until in the last
there are eight. On a rocking spindle R, at its one end, there is an arm carrying
a roller which bears against the surface of the drum Q, and at the other end of the
spindle R there is another arm 7, bearing on the vertical spindle of the gas valve
above the passage y, which valve is kept closed by a spring S, but which is opened
in opposition to the spring when one of the cam projections of the drum Q causes
the spindle R to rock. If the attendant, by means of the lever E¹, moves the
drum Q so as to bring opposite the roller that section of the drum which presents
8 projections, then the gas valve will be opened 8 times during one revolution of
the drum, or during 16 revolutions of the engine shaft, that is to say, it will be
opened once in every two revolutions of the engine shaft, and therefore for every
charging stroke of the piston, which occurs once in every two revolutions. When it

page_text: is desired to reduce the power or speed of the engine the attendant, by means of
the lever E¹, moves the drum Q so as to bring opposite to the roller a section of
the drum presenting a smaller number of cam projections, and he can thus cause
the gas supply to be stopped once, twice, thrice, or more times in every 8 charging
strokes, as the case may be. Assuming the engine to be working at full power,
receiving supply of gas at each charging stroke, then the cycle of operations is as
follows The piston having made its instroke and reached the position indicated
in Fig. 2, the space in the cylinder behind it is filled with air; the valves of land e
are closed, and the slide F is moving so as to bring its cavity finto communication
with the part i. The piston being caused to make its outstroke by the momentum
of the flywheel draws in behind it air supplied from the passage a mixed with gas
from I, the gas valve being at this time open. Thus a combustible mixture of air
and gas is drawn into the cylinder, this mixture becoming partly dispersed among
the air which previously occupied the space of the cylinder, but its strongest or
most combustible portion remaining in and near the part i. The slide F having
now moved so as to close the part i, the piston makes its back stroke, compressing
the mixed fluids in the cylinder, and the slide F, by its continued movement, brings
the igniting passage c in communication with i. The combustible mixture having
still its greatest strength next the part i being ignited burns throughout the body
af air among which it was more or less dispersed, causing an increase of pressure in
the cylinder, whereby the piston is propelled. The piston having completed its
outstroke the valves e and are opened by the action of the tappet levers O and N,
as above described, and as the piston makes its instroke the products of combustion
are expelled, and the space in the cylinder behind the piston remains occupied
mostly by air. The like cycle of operations is then repeated. When the regulating
drum Qis so set as to prevent gas supply during any charging stroke, the cycle of
which that stroke forms part is ineffective for the production of power, the piston
working idly during that cycle; and thus by rendering any one, two, three, or
more of the 8 cycles ineffective the power or speed of the engine can be varied us
desired. Although I have shewn a regulating arrangement adapted for 8 cycles
any other number might be chosen, the drum Q being made with the desired
number of sets of cam projections. The regulating apparatus as above described is
applicable generally to gas motor engines in which the supply of gas is controlled
by a valve which can be worked by cam projections in the manner set forth.
Although in what precedes I have assumed that the ignition of the combustible
charge in the cylinder is effected by flame it is to be understood that the ignition
might be effected in other known ways, as, for example, by electricity or by a
heated metal without interfering with the action of the air pump or the regulating
apparatus.
Having thus described the nature of my Invention, and in what manner the
same is to be performed, I hereby declare that I make no general claim to the
construction and operation of a gas motor engine in which the piston by one
outstroke draws in a combustible charge to partly mix with the contents of a space
in the cylinder, by its instroke compresses the contents of the cylinder, is propelled
throughout an outstroke by the pressure resulting from the combustion of the
charge, and by its succeeding instroke expels products of combustion, but I claim
in respect of gas motor engines,-
First. Forcing air into the cylinder while the products of combustion are being
expelled, so that the space in the cylinder behind the piston before the admission
of the combustible charge may be mostly occupied by air, substantially as herein
described.
Second. The combination with the engine and its exhaust valve, of an air com-
pressing pump and valve, and gear for working it so as to introduce air into
the cylinder during the expelling stroke of the piston, substantially as herein
described.
Third. The use for regulating the engine power or speed, of a revolving drum
having various numbers of cam projections for opening the gas supply valve

page_text: arranged in sets, so that according as one or another of these sets is brought into
action, the engine is caused to make idle strokes at greater ar less intervals,
substantially as herein described.
Fourth. The combination of the spindle P driven at a slow speed relatively to
the engine shaft, the drum Q fitted to slide along and revolve with P, and provided
with several sets of cam projections differing in number, any of which sets can be
brought to act on the gas supply valve, substantially as and for the purpose herein
set forth.
In witness whereof, I, the said Francis William Crossley, have hereunto set
my hand and scal, this Nineteenth day of April, in the year of our Lord
One thousand eight hundred and eighty one.
FRANCIS WILLIAM CROSSLEY. (L.S.)