Improvements in Compound Internal Combustion Motors.
Year: 1898

page_text: PROVISIONAL SPECIFICATION.
Improvements in Compound Internal Combustion Motors.
We, WILLIAM JOHN CROSSLEY, of Crossley Brothers Limited, Openshaw,
Manchester, and JAMES ATKINSON, of The Woodlands, Marple, Cheshire,
Engineers, do hereby declare the nature of this invention to be as follows:-
In our improved compound internal combustion motor we employ three
cylinders, two of them being high pressure cylinders in which the charge is drawn
or four stroke cycle
in, compressed, ignited and expanded on the ordinary "Otto
and the other being the low pressure cylinder.
33
The low pressure cylinder preferably is placed between the high pressure
cylinders and has its piston connected in the ordinary manner to a crank pin on
the crank shaft common to all the cylinders. The high pressure cylinders have
their pistons connected to crank pins in such a manner that they complete their
inward and outward strokes together but at an interval of 180 degres from the
crank pin of the low pressure piston, that is to say when the high pressure pistons
are in their furthest out position, the low pressure piston is at its furthest in
position.
The low pressure cylinder is about twice the area of the high pressure cylinders
and the mouths of all the cylinders open into an enclosed chamber containing the
crank shaft and the connecting rods. Owing to the positions of the cranks and
the areas of the pistons the pressure in the enclosed chamber remains uniform
during their movements.
The low pressure piston and connecting rod are made about the weight of
the two high pressure pistons and their connecting rods, so that by balancing
the rotating parts the engine is suitable for running at a high rate of speed
without causing any material vibration or requiring heavy foundations.
The valves for the admission of gas and air and for the exhaust of the high
pressure cylinders are similar to those we use for ordinary engines, but are so
arranged that working strokes are made alternately, thus providing for an impulse
each revolution. After a working stroke in either high pressure cylinder the
exhaust takes place into the low pressure cylinder, and as these exhausts take
place alternately from either high pressure cylinder, power is given out by the low
pressure piston once every revolution and between the working strokes in the
high pressure cylinders. Power is thus given out twice per revolution when
ignitions are allowed to take place continuously in the high pressure cylinders.
Interposed between the high pressure exhaust valves and the low pressure
cylinder a valve (or valves) is placed. This valve may be a piston valve driven
by means of an eccentric or crank pin on one of the cam shafts which revolves
once for each two revolutions of the engine crank shaft. By means preferably of
two ports into the low pressure cylinder, a port into the atmosphere, and three
pistons or discs forming the piston valve, the following sequence of operations
takes place:-Passage clear for the exhaust from say the left high pressure
cylinder to the low pressure cylinder owing to the position of the piston valve
but the actual timing of this exhaust deferred and defined by the opening of the

page_text: left high pressure exhaust valve. Outward stroke of the low pressure piston
towards the end of which the exhaust from the low pressure cylinder to the atmo-
sphere is opened by the pistol valve. Free passage opened from the left high
pressure cylinder to the atmosphere whilst its piston is at about its inward dead
centre and just before it coinmences its suction stroke both piston valve &
exhaust valve being open. Passage from the left high pressure cylinder cut off
by the piston valve. Inward exhaust stroke of the low pressure piston, the exhaust
continued throughout the greater part of this stroke by the piston valve being
open. Opening of the exhaust passage from the right high pressure cylinder by
the piston valve but the actual timing of this exhaust deferred and defined by the
opening of the right high pressure exhaust valve. Closing of the exhaust from
the low pressure cylinder by the piston valve so as to provide for a slight com-
pression filling its clearance spaces. Opening of the right high pressure exhaust
valve. Outward stroke of the low pressure piston towards the end of which the
exhaust from the low pressure cylinder is opened by the piston valve. Free
passage opened from the right high pressure cylinder to the atmosphere both the
piston valve and the high pressure exhaust valve being open whilst its piston is
about at its inward dead centre and just before it commences its suction stroke.
Passage from the right high pressure cylinder cut off by the piston valve. Inward
exhaust stroke of the low pressure piston, the exhaust continuing throughout
the greater part of this stroke, by the piston valve being open. Opening of the
exhaust passage from the left high pressure cylinder by the piston valve, but the
actual timing of this exhaust deferred and defined by the opening of the left high
pressure exhaust valve. Thus the cycle of movements is completed by one
backwards and forwards movement of the piston valve whilst the engine makes
two complete revolutions. In a quick running engine the slower reciprocation of
the piston valve is a great advantage. Modified arrangements of this valve may
be used but the sequence of operations above described is necessary to give the
best results.
A further advantage derived is that the piston valve cuts off the exhaust from
both high pressure cylinders alternately thus whilst they are making their suction
strokes, their respective exhaust valves may be allowed to close slowly and
quietly a considerable period of time after their actual exhausts have been
completed.
Tlated this 91at dow of Donaushan 1000
We, WILLIAM JOHN CROSSLEY, of Crossley Brothers, Limited, Openshaw,
Manchester, and JAMES ATKINSON, of "The Woodlands," Marple, Cheshire,
Engineers, 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 our improved compound internal combustion motor we employ three
cylinders, two of them being high pressure cylinders in which the charge is
drawn in, compressed, ignited and expanded on the ordinary "Otto" or four stroke
cycle and the other being the low pressure cylinder.
To enable this invention to be properly understood we append three sheets
of drawings in which Fig. 1, Sheet 1, is a sectional elevation through the cylinders
and main bearings. Fig. 2, Sheet 2, is a plan of the upper part of the engine,

page_text: partly in section, and Figs. 3 4, 5 and 6, Sheet 3, are sectional views, more or less
diagramatical, showing the action of the valves regulating the admission and
exhaust of the gases from the high pressure cylinders to and from the lower
pressure cylinder.
The low pressure cylinder A preferably is placed between the high pressure
cylinders B and C. It has its piston D connected in the ordinary manner to a
crank pin E on the crank shaft F common to all the cylinders. The high pressure
cylinders B and C have their pistons connected to crank pins G and H in such a
manner that they complete their inward and outward strokes together but at an
interval of 180 degrees from the crank pin E of the low pressure piston D, that
is to say when the high pressure pistons are in their furthest in position, the
low pressure piston D is at its furthest out position, as shown in Fig. 1, Sheet 1.
The low pressure cylinder A is about twice the area of the high pressure
cylinders B and C. The mouths of all the cylinders open into an enclosed
chamber I containing the crankshaft F and the connecting rods. Owing to the
positions of the cranks and the areas of the pistons the pressure in the enclosed
chamber remains uniform during their movements.
The low pressure piston D and its connecting rod are made about the weight
of the two high pressure pistons and their connecting rods, so that by balancing
the rotating parts the engine is suitable for running at a high rate of speed
without causing any material vibration or requiring heavy foundations.
The valves for the admission of gas and air and for the exhaust of the high
pressure cylinders B and C are similar to those we use for ordinary engines, but
are so arranged that working strokes are made alternately, thus providing for an
impulse cach revolution. After a working stroke in either high pressure cylinder
the exhaust takes place into the low pressure cylinder, and as these exhausts
take place alternately from either high pressure cylinder, power is given out by
the low pressure piston once every revolution and between the working strokes
in the high pressure cylinders. Power is thus given out twice per revolution when
ignitions are allowed to take place continuously in the high pressure cylinders.
Interposed between the high pressuré exhaust valves and the low pressure
cylinder a valve J (or valves) is placed. This valve J may be a piston valve as
shown driven by means of an eccentric or crank pin L. on one of the cam shafts M
which revolves once for each two revolutions of the engine crank shaft F. By
means preferably of two ports N₁ and N³ into the low pressure cylinder A, a
port O into the atmosphere, and three pistons or discs P, Q and R forming the
piston valve, the following sequence of operations takes place:-Passage clear
for the exhaust from say the left high pressure cylinder B to the low pressure
cylinder A owing to the position of the piston valve but the actual timing of this
exhaust deferred and defined by the opening of the left high pressure exhaust
valve S. Outward stroke of the low pressure piston D towards the end of which
the exhaust from the low pressure cylinder to the atmosphere is opened by the
piston valve J. Free passage opened from the left high pressure cylinder to the
atmosphere whilst its piston is at about its inward dead centre and just before it
commences its suction stroke both piston valve J and exhaust valve S being open:
this position is shown in Fig. 1, Sheet 1, where it will be seen that the disc P
of the valve J is not so wide as the port N¹ leaving a free passage from the
cylinders B and A to the atmosphere. The valve J at this time is moving in the
direction shown by the arrow. Passage from the left high pressure cvlinder
cut off by the disc P of the piston valve J. Inward exhaust stroke of the low
pressure piston, the port N¹ being open to the port O, the exhaust continuing
throughout the greater part of this stroke by these passages through the piston
valve J being open. Opening of the exhaust passage from the right high pressure
cvlinder by the piston valve but the actual timing of this exhaust deferred and
defined by the opening of the right high pressure exhaust valve. Closing of
the exhaust from the low pressure cylinder A by the piston valve J so as to provide
for a compression filling its clearance spaces. Opening of the right high pressure

page_text: exhaust valve. Outward stroke of the low pressure piston D towards the end of
which the exhaust from the low pressure cylinder A is opened by the piston
valve J. Free passage opened from the right high pressure cylinder C to the
atmosphere both the piston valve J and the high pressure exhaust valve being
open whilst its piston is about at its inward dead centre and just before it com-
mences its suction stroke, the disc R of the valve J being opposite the port N.
but not being so wide as the port free passage is left from the cylinder A and the
cylinder C. Passage from the right high pressure cylinder C cut off by the piston
valve J. Inward exhaust stroke of the low pressure piston D, the exhaust con-
tinuing throughout the greater part of this stroke, by the piston valve J being
open. Opening of the exhaust passage from the left high pressure cylinder B.
by the piston valve J but the actual timing of this exhaust deferred and defined
by the opening of the left high pressure exhaust valve S. Thus the cycle of
movements is completed by one backwards and forwards movement of the piston
valve whilst the engine makes two complete revolutions. In a quick running
engine the slower reciprocation of the piston valve J is a great advantage.
Modified arrangements of this valve may be used but the sequence of operations
above described is necessary to give the best results.
Figs. 3, 4, 5 and 6, Sheet 3, more clearly show the movements of the piston
valve Jin relation to the movements of the pistons. These figures are
diagramatical.
Fig. 3 shows to a large scale the position of the valve J, the pistons of the two
high pressure cylinders and the piston of the low pressure cylinder in the same.
position as they are in Fig. 1 Sheet 1 and Fig. 2 Sheet 2. At this time the left
hand nigh pressure piston is about to commence its suction stroke but as will be
seen there is a clear passage to the atmosphere round the edges of the disc P,
this passage however is about to be closed by the movement of the disc P
in the direction shown by the arrow, this movement also opening wide the
port N for the exhaust from the low pressure cylinder A to the atmosphere.
In Fig. 4 Sheet 3 the engine has moved more than half revolution from the
position shown in Fig. 3 and as will be seen the port N2 is fully open to allow
exhaust from the right hand high pressure cylinder C to pass into the low pressure
cylinder A to drive its piston down, the left hand high pressure piston moving
upwards compressing a charge for the next ignition.
Fig. 5 Sheet 3 shows the low pressure piston almost at the end of its working
stroke and the valve J on the point of opening the exhaust from the low pressure
cylinder A, the disc R just about to open the port N2 and also as the disc R is
not so wide as the port N² the right hand high pressure cylinder is also for a short
time opened to the atmosphere to ensure a complete exhaust before it commences
a suction stroke.
Fig. 6 Sheet 3 shows the piston valve J in mid-position both ports N¹ and N
being full open to the exhaust port O allowing for a free exhaust from the low
pressure cylinder A as its piston D moves upwards.
In the Figs. 3, 4, 5 and 6, Sheet 3, the exhaust valves for the high pressure
cylinders are omitted but it is to be understood that in the arrangement shown
they are used to time the exhaust from the high pressure cylinders into the low
pressure cylinder the piston valve J having previously opened the communication.
A further advantage derived is that the piston valve cuts off the exhaust from
both high pressure cylinders alternately, so that whilst they are making their
suction strokes their respective exhaust valves may be allowed to close slowly and
quietly a considerable period of time after their actual exhausts have been
completed.
Having now particularly described and ascertained the nature of our said
invention, and in what manner the same is to be performed, we declare that what
we claim is:-
1. The general arrangement and construction of compound internal combustion
motors having two high pressure cylinders one on either side of one low pressure

page_text: cylinder of approximately double the capacity the low pressure crank pin being
opposite the two high pressure crank pins the mouths of all the cylinders opening
into an enclosed chamber in which a uniform pressure is thus maintained and
in which the connecting rods and crank shaft work all in combination with suitable
valve gear enabling working strokes to be made in each high pressure cylinder
once every two revolutions but alternating so that there may be a working stroke
once every revolution and a high pressure exhaust also once every revolution into
the low pressure cylinder together with a low pressure exhaust on each up stroke
of the low pressure piston substantially as described and illustrated.
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2. In compound internal combustion motors having two high pressure cylinders
working on the "Otto or four stroke cycle in connection with one low pressure
cylinder the use of the piston valve J reciprocating at half the speed of the crank-
shaft for the purpose of controlling the exhausts from the high pressure cylinders
to the low pressure cylinder and thence to the atmosphere as described and
illustrated.
3. In compound internal combustion motors having two nigh pressure cylinders
working on the "Otto" or four stroke cycle in conjunction with one low pressure
cylinder the use of ordinary exhaust valves to the high pressure cylinders together
with the piston valve J reciprocating at half the speed of the crank shaft for the
purpose of controlling the exhausts from the high pressure cylinders to the
low pressure cylinder and thence to the atmosphere as described and illustrated.
4. The general arrangement and construction of compound internal combustion
motors having two high pressure cylinders giving alternate working strokes on
the "Otto" or four stroke cycle in conjunction with one low pressure cylinder of
double the capacity having suitable exhaust valves to the high pressure cylinders and
the piston valve J reciprocating at half the speed of the crankshaft for controlling
the working fluid from the high pressure cylinders into and from the low pressure
cylinder and having the mouths of all the cylinders opening into an enclosed
chamber in which there is thus a practically uniform pressure substantially as
described and illustrated.
5. The general arrangement and construction of compound internal combustion
motors substantially as described and illustrated.
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