U.S. patent number 3,608,530 [Application Number 05/015,999] was granted by the patent office on 1971-09-28 for lever-type two-cycle internal combustion engine.
Invention is credited to Edward C. Wenzel.
United States Patent |
3,608,530 |
Wenzel |
September 28, 1971 |
LEVER-TYPE TWO-CYCLE INTERNAL COMBUSTION ENGINE
Abstract
An internal combustion engine having opposed power cylinders and
separate air or air-fuel charging cylinders, and a lever system
interconnecting the power and air or air-fuel charging cylinder
pistons with each other and with a crankshaft. The lever system
comprises the piston rods of the power and air or air-fuel pistons,
each piston rod being pivotally connected at one end to its
respective piston and being pivotally connected at its opposite end
to the corresponding opposite ends of the other two piston rods.
One of said piston rods--namely, the piston rod of the air or
air-fuel charging cylinder--is connected intermediate its ends to a
crankshaft and said piston rod accordingly functions as the lever
which drives the crank arm of the engine.
Inventors: |
Wenzel; Edward C. (Sparta,
NJ) |
Family
ID: |
21774803 |
Appl.
No.: |
05/015,999 |
Filed: |
March 3, 1970 |
Current U.S.
Class: |
123/53.4;
123/55.7 |
Current CPC
Class: |
F02B
33/00 (20130101); F02B 25/00 (20130101); F02B
75/246 (20130101); F02M 2700/333 (20130101); F02B
2700/031 (20130101) |
Current International
Class: |
F02B
25/00 (20060101); F02B 75/24 (20060101); F02B
33/00 (20060101); F02B 75/00 (20060101); F02b
075/24 () |
Field of
Search: |
;123/56B,56BA,56BB,56BC |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
510,522 |
|
Oct 1930 |
|
DD |
|
1,093,102 |
|
Nov 1954 |
|
FR |
|
Primary Examiner: Burns; Wendell E.
Claims
What is claimed is:
1. In a lever-type internal combustion engine, the combination
of:
a. a crankshaft,
b. a plurality of power cylinders and air charging cylinders
communicating with said power cylinders,
c. said power and air charging cylinders being each provided with a
piston and a piston rod pivotally connected at its inner end with
said piston, and
d. a lever system whereby the power cylinder pistons and piston
rods drive the crankshaft,
e. said lever system consisting of the piston rods of the power and
air charging cylinders pivotally interconnected at their outer
ends,
f. the piston rods of the air charging pistons being also
operatively connected intermediate their ends to the
crankshaft,
g. whereby said air charging cylinder piston rods function as
second class levers between the power cylinder piston rods and the
crankshaft,
h. The pivotal connection between the piston and inner end of the
piston rod of the air charging cylinders functioning as the fulcrum
of the lever,
i. the pivotal connection between the outer end of the piston rod
of the air charging cylinders and the outer end of the piston rod
of the power cylinders functioning as the force applying point of
the lever, and
j. the operative connection between the crankshaft and the piston
rod of the air charging cylinders functioning as the load applying
point of the lever.
2. A lever-type internal combustion engine in accordance with claim
1, wherein:
a. the power cylinders are arranged in linearly opposed pairs
b. to enable each cylinder of each pair of power cylinders to
absorb the inertial thrust of the piston and piston rod of the
other cylinder.
3. A lever-type internal combustion engine in accordance with claim
1, wherein:
a. one air charging cylinder is provided for two power
cylinders,
b. the volumetric capacity of each said air charging cylinder being
sufficient to concurrently scavenge and recharge both power
cylinders.
4. A lever-type internal combustion engine in accordance with claim
3, wherein:
a. the power cylinders are provided with inlet and outlet ports,
and
b. means for concurrently opening both ports,
c. whereby the power cylinders may concurrently be scavenged and
recharged by the air charging cylinders with which they are in
communication.
5. In a lever-type internal combustion engine, the combination
of:
a. a plurality of power cylinders arranged in pairs,
b. each pair of power cylinders being coaxially aligned in opposed
positions,
c. pistons in each pair of opposed power cylinders,
d. piston rods pivotally connected at their respective inner ends
to said pistons,
e. said piston rods being pivotally connected at their outer ends
to each other,
f. a plurality of air charging cylinders,
g. there being one air charging cylinder for each pair of opposed
power cylinders,
h. a piston in each said charging cylinder,
i. a piston rod pivotally connected at its inner end to each said
charging cylinder piston,
j. the outer end of the piston rod of each charging cylinder being
pivotally connected to the pivotally connected outer ends of the
piston rods of the corresponding pair of opposed power cylinders,
and
k. a crankshaft having a plurality of crankpins, one for each air
charging cylinder,
l. the piston rod of each said charging cylinder being operatively
connected intermediate its inner and outer ends to one of the
crankpins of the crankshaft,
m. whereby the piston rod of each said charging cylinder functions
as a lever of the second class between the piston rods of the
corresponding pair of opposed power cylinders and the
crankshaft,
n. the pivotal connection at the inner end of the piston rod of
each charging cylinder comprising the fulcrum of the lever,
o. the pivotal connection at the outer end of the piston rod of
each charging cylinder being the point at which force is applied to
the lever by the piston rods of the pair of opposed power
cylinders,
p. The operative connection intermediate the inner and outer ends
of the piston rod of each charging cylinder being the point of
applied load between the lever and the corresponding crankshaft
pin.
6. A lever-type internal combustion engine in accordance with claim
5, wherein:
a. there are four pairs of opposed power cylinders, and
b. four air charging cylinders,
c. the four pairs of opposed power cylinders being arranged in
parallel side-by-side relationship in a first common plane,
d. the four air charging cylinders being arranged in parallel
side-by-side relationship in a second common plane,
e. the crankshaft being also disposed in said second plane as well
as in a third plane,
f. the first and third planes being parallel to each other and
perpendicular to the second plane.
7. A lever-type internal combustion engine in accordance with claim
5, wherein:
a. the first plane in which the power cylinders are disposed and
the third plane in which the crankshaft is disposed are horizontal,
and
b. the second plane in which the charging cylinders and crankshaft
are disposed is vertical.
8. A lever-type internal combustion engine in accordance with claim
5, wherein:
a. the stroke of the pistons of the power cylinders is relatively
long, and
b. the bore of said power cylinders is relatively small,
c. such that the length of the stroke exceeds the diameter of the
bore.
9. A lever-type internal combustion engine in accordance with claim
5, wherein:
a. each air charging cylinder communicates with two power
cylinders,
b. the volumetric air charging capacity of each said charging
cylinder being sufficient for concurrent scavenging and recharging
of the two power cylinders with which it communicates.
10. A lever-type internal combustion engine in accordance with
claim 5, wherein:
a. the power cylinders are provided with inlet and outlet
ports,
b. the pistons within said power cylinders being adapted to open
and close said inlet and outlet ports,
c. and being adapted to open both ports concurrently to enable the
communicating air charging cylinder to concurrently scavenge and
recharge the power cylinders,
d. said pistons being also adapted to close both ports for the
compression and power strokes of said power cylinders.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
Lever-type internal combustion engines, whether based on gasoline
or diesel engine principles.
2. Description of the Prior Art
The use of lever-type engines dates back to the early days of
automotive and internal combustion engine development. Historic
advances in engine design necessarily include the brainchild of
Alvah A. Powell, who saw advantages in changing long stroke piston
travel to shorter crank throw through leverage. More recent
improvements include opposed cylinder two-cycle engines such as the
type disclosed in U.S. Pat. No. 2,445,720 to Wenzel.
Known engines, however, include many undesirable features which
designers in the art have unsuccessfully sought to overcome.
Relatively complicated linkages with long connecting rods are
characteristic of engines known to the art. In addition, vibration
problems created by imbalance of moving parts result in a loss of
engine efficiency as well as ever increasing engine wear. The use
of flywheels mounted on the ends of crankshafts and equipped with
counterbalance weights have only added to already complicated
engine structures.
SUMMARY OF THE INVENTION
This invention relates to two-cycle internal combustion engines.
The same principle, although not here specified, may be used in
external combustion engines such as steam engines, in which a
relatively large stroke-to-bore ratio is desirable for increasing
crankshaft torque. The invention will, however, be described herein
in relation to a two-cycle internal combustion engine, but this
description is not intended to limit the application of the
invention except to the extent and scope of the appended
claims.
Specifically, in the present invention the power cylinders are
axially aligned in opposed positions, the piston rod of each said
power (work) cylinder being pivotally connected at its outer end to
the corresponding end of the piston rod of the opposed power
cylinder. An air or air-fuel charging cylinder is provided for each
pair of opposed power cylinders. Its longitudinal axis intercepts
the common longitudinal axis of the two power cylinders at right
angles thereto. In the preferred form of this invention the opposed
power cylinders occupy a common horizontal plane. The air or
air-fuel charging cylinder extends vertically, its longitudinal
axis being normal to said horizontal plane.
The piston rod of the air or air-fuel charging cylinder is
connected at its outer (lower) end to the connected outer ends of
the piston rods of the horizontally opposed power cylinders. The
relationship of all three piston rods to their respective pistons
and to each other is the same in all three cases--that is, the
inner end of each piston rod is pivotally connected to its
respective piston, and the outer end of each piston rod is
pivotally connected to the corresponding outer ends of the other
two piston rods.
The crankshaft is located above the horizontally opposed power
cylinders and below the vertically extending air or air-fuel
charging cylinder. The piston rod of the air or air-fuel charging
cylinder is connected, intermediate its ends, to the offset crank
pin of the crankshaft. Accordingly, for the purposes of this
description, the piston rod of the air or air-fuel charging
cylinder may be considered to be the operative lever of the lever
system of the present invention. In this arrangement, the inner end
of the lever (connected to the piston rod of the air or air-fuel
charging cylinder) is its fulcrum end; the outer end of said lever
(which is connected to the outer ends of the piston rods of the
power cylinders) may be considered to be its effort end; and the
intermediate connection between the lever and the crankshaft may be
considered to be the load or work-applying portion of the
lever.
It will be understood from this description and from the appended
drawing that there is no fixed axis for any part of the lever. The
fulcrum moves linearly in a vertical line, reciprocating between
upper and lower positions. The load- or work-applying portion of
the lever rotates in a circular path about the crankshaft axis. The
effort end of the lever describes an orbital path.
The principal object of this invention is the provision of a
lever-type engine of the character described, wherein the power or
work cylinders are axially aligned and opposed to provide a direct
thrust, inertia absorbing cushion in each cylinder of each pair of
opposed cylinders, thereby freeing the crankshaft from excessive
inertial loading, and rendering it feasible to provide a relatively
large stroke-to-bore ratio in the power cylinders.
It is an object of this invention to provide a lever-type engine of
the character described which employs the slidable fulcrum
principle in order to produce a relatively large stroke-to-bore
ratio in the power cylinders, while employing a small crank arm
radius and relatively short connecting linkages between the pistons
and the crankshaft.
Another object of the invention is to increase piston dwell time at
each end of the power piston stroke, thereby increasing the time
for homogenization of the air-fuel mixture to promote more complete
combustion within the power cylinder at the end of the compression
stroke and beginning of the power stroke, and more complete
scavenging and recharging at the end of the power stroke and
beginning of the compression stroke.
A further object of this invention is to provide, within feasible
total volume, an engine having a long piston stroke relative to the
cylinder diameter to promote more complete combustion of the
air-fuel mixture taken into the cylinder such that pressure and
combustion levels approach zero value before the exhaust port is
opened at the end of the power stroke.
A still further object of the invention is to provide an internal
combustion engine which will produce minimum exhaust pressure and
particle emission to minimize air pollution.
The present invention provides a lever engine comprising a
plurality of power cylinders (preferably in multiples of four or
eight) arranged in pairs in such manner that the cylinders of each
pair are directly opposed in coaxial relationship in a horizontal
plane. In an eight-cylinder engine as herein shown and described,
there are four pairs of opposed cylinders arranged side by side in
parallel relationship in a common horizontal plane. There is a
single air or air-fuel charging cylinder for each pair of opposed
power cylinders, and in an engine having four pairs of opposed
power cylinders (eight cylinders in all) there are four charging
cylinders. These charging cylinders are arranged side by side in
parallel relationship, in a common vertical plane, the axes of said
charging cylinders extending vertically and intercepting the power
cylinder axes at right angles. The crankshaft extends horizontally
in the vertical plane which the charging cylinders occupy, and in a
horizontal plane above the horizontal plane which the opposed power
cylinders occupy. The crankshaft has four crank arms which are
equally spaced from each other at 90.degree. intervals, there being
one crank arm for each pair of opposed cylinders. Power is
delivered to the crankshaft by at least two power cylinders at all
times. Each air or air-fuel charging cylinder supplies two power
cylinders with air or an air-fuel mixture, there being four
charging cylinders and eight power cylinders. Each charging
cylinder will communicate with two power cylinders when their
respective inlet ports are opened at the end of a power or work
stroke. At such time the piston of the charging cylinder will reach
its extreme upper position in its upwardly moving compression
stroke, so as to deliver the required charge of air or air-fuel
mixture to the two power cylinders with open inlet ports.
As has above been stated, the lever system of each pair of opposed
power cylinders and their adjacent charging cylinder comprises the
piston rods of the three cylinders pivotally connected to each
other at their respective outer ends. The piston rod of the
charging cylinder is connected intermediate its ends to the
crankshaft, and accordingly may be deemed and designated the lever
of the lever-type engine herein described and claimed. The charging
cylinder (piston) performs two functions:
1. It provides compressing means for compressing air or an air-fuel
mixture and delivering same to the power cylinders.
2. It provides a vertically reciprocating fulcrum for the lever
which drives the crankshaft.
It is this arrangement, wherein the three piston rods (of each pair
of work cylinders and one air-charging cylinder) comprise the
entire lever system of the engine, that renders it possible to
dispense with the complicated lever systems and linkages of the
lever engines of the prior art. It is the use of the pivotal
connection between the piston of the air-charging cylinder and its
piston rod as the fulcrum of the lever system that makes it
possible to dispense with the supplemental fulcrum systems of prior
engines.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a plan view of an eight-cylinder, two-cycle engine made
in accordance with the principles of this invention.
FIG. 2 is a section through a vertical plane which is parallel to
the axis of the crankshaft and taken on the line 2--2 of FIG.
12.
FIG. 3 is a second vertical section corresponding to FIG. 2 but
taken on the line 3--3 of FIG. 13.
FIG. 4 is a third vertical section corresponding to FIG. 2 but
taken on the line 4--4 of FIG. 14.
FIG. 5 is a fourth vertical section corresponding to FIG. 2 but
taken on the line 5--5 of FIG. 15.
FIG. 6 is a fifth vertical section corresponding to FIG. 2 but
taken on the line 6--6 of FIG. 16.
FIG. 7 is a section through a vertical plane which is at right
angles to the axis of the crankshaft and is taken on the line 7--7
of FIG. 2.
FIG. 8 is a second vertical section corresponding to FIG. 7 but
taken on the line 8--8 of FIG. 3.
FIG. 9 is a third vertical section corresponding to FIG. 7 but
taken on the line 9--9 of FIG. 4.
FIG. 10 is a fourth vertical section corresponding to FIG. 7 but
taken on the line 10--10 of FIG. 5.
FIG. 11 is a fifth vertical section corresponding to FIG. 7 but
taken on the line 11--11 of FIG. 6.
FIG. 12 is a section through a horizontal plane and taken on the
line 12--12 of FIG. 2.
FIG. 13 is a second horizontal section corresponding to FIG. 12 but
taken on the line 13--13 of FIG. 3.
FIG. 14 is a third horizontal section corresponding to FIG. 12 but
taken on the line 14-14 of FIG. 4.
FIG. 15 is a fourth horizontal section corresponding to FIG. 12 but
taken on the line 15--15 of FIG. 5.
FIG. 16 is a fifth horizontal section corresponding to FIG. 12 but
taken on the line 16--16 of FIG. 6.
DESCRIPTION OF PREFERRED EMBODIMENT OF THE INVENTION
Referring now to the details of the invention as illustrated in the
drawing, it will be observed that there are four pairs of power
cylinders, eight power cylinders in all, designated respectively as
follows: 10a and 10b, 12a and 12b, 14a and 14b, and 16a and 16b.
Associated with these four pairs of power cylinders are four air or
air-fuel charging cylinders, designated respectively 10c, 12c, 14c
and 16c. A housing 20 supports the power and charging cylinders in
the arrangement shown in the drawing, and it will shortly be
described. Also supported by and within the housing is a crankshaft
22, there being only one crankshaft for the eight power cylinders
and the four charging cylinders.
It will now be observed that the eight power cylinders are disposed
in a common horizontal plane, each pair of said cylinders being
coaxially aligned and opposed, the four pairs of opposed cylinders
being arranged in side-by-side relationship so that the
longitudinal axis of each pair is parallel to the longitudinal axes
of the other three pairs. The charging cylinders are also arranged
in side-by-side relationship, their respective longitudinal axes
being disposed in parallel relationship to each other in a common
vertical plane centered between power cylinders 10a, 12a, 14a and
16a, on the one hand, and power cylinders 10b, 12b, 14b and 16b, on
the other hand. The longitudinal axis of crankshaft 20 also lies in
the vertical plane of the charging cylinders, and it is also
disposed in a horizontal plane located between the power cylinders
on the one hand and the charging cylinders on the other.
It will be understood that the power cylinders are respectively
provided with pistons and piston rods designated as follows:
power cylinder 10a--piston 10d, piston rod 10e
power cylinder 10b--piston 10f, piston rod 10g
power cylinder 12a--piston 12d, piston rod 12e
power cylinder 12b--piston 12f, piston rod 12g
power cylinder 14a--piston 14d, piston rod 14e
power cylinder 14b--piston 14f, piston rod 14g
power cylinder 16a--piston 16d, piston rod 16e
power cylinder 16b--piston 16f, piston rod 16g
By the same token, the air or air-fuel charging cylinders are also
provided with pistons and piston rods designated as follows:
charging cylinder 10c--piston 10h, piston rod 10i
charging cylinder 12c --piston 12h, piston rod 12i
charging cylinder 14c--piston 14h, piston rod 14i
charging cylinder 16c--piston 16h, piston rod 16i
The crankshaft 22 has four crank pins spaced at 90.degree.
intervals and designated as follows:
for piston rod 10i--crankpin 22a
for piston rod 12i--crankpin 22b
for piston rod 14i--crankpin 22c
for piston rod 16i--crankpin 22d
With further reference to the details of the invention as
illustrated in the drawing, it will be noted that the power
cylinders are provided with heat exchange fins 24. It will thereby
be understood that the preferred embodiment of the invention is an
air-cooled engine. However, it should also be understood that the
invention is not intended to be limited to air-cooled engines, and
the principles of the invention may equally be applied to engines
which are water-cooled.
It will further be noted that the power cylinders are long in
relation to the diameter of their respective pistons, that is, the
length of the stroke of the power pistons exceeds their diameter.
This is known as an undersquare design, and the ratio of
stroke-to-bore may exceed 1:1 to any desired extent, even as high
as approximately 2:1, as schematically shown in the drawing. The
invention is not limited to any specific stroke-to-bore ratio.
The mechanical linkages which are significant in the execution of
this invention are the following: The pistons rods of the several
power cylinders are pivotally connected at their inner ends to
their respective pistons by means of cross pins 26. The piston rods
of each pair of power cylinders are pivotally connected to each
other by means of cross pins 28. Similarly, the piston rods of the
several air charging cylinders are pivotally connected at their
inner ends to their respective pistons by means of cross pins 30.
At their outer ends the piston rods of the air charging cylinders
are pivotally connected to the outer ends of the piston rods of the
power cylinders by means of above mentioned pin 28. It will
accordingly be understood that the several piston rods of the power
and air charging cylinders are pivotally connected at their inner
ends to their respective pistons and pivotally connected at their
outer ends to each other.
The piston rods of the air charging cylinders are also connected to
the crankshaft. More particularly, piston rod 10i is rotatably
connected to crank pin 22a, piston rod 12i is rotatably connected
to crank pin 22b, piston rod 14i is rotatably connected to crank
pin 22c, and piston rod 16i is rotatably connected to crank pin
22d. The crankshaft is, of course, adequately supported by bearings
in any conventional manner. Schematically it is indicated in the
drawing that the housing is provided with five bearing blocks, 32,
32a, 32b, 32c and 32d, respectively; suitable split bearing sleeves
34, 34a, 34b, 34c and 34d are provided to support the crankshaft on
said bearing blocks. Spacer sleeves 36 are provided where
necessary. However, it will be understood that the drawing is
primarily schematic and the showing of the several working parts is
exaggerated for purposes of clarity, and relative proportions of
the parts as shown in the drawing should not be taken literally.
This is particularly true of the crankshaft, including the spacing
between the bearing supports and the crank pins.
As has above been indicated, this invention is primarily applicable
to two-cycle internal combustion engines, and the engine which is
shown in the drawing illustrates this application of the invention.
There is no valve system connected with the power cylinders other
than open ports formed in those cylinders and the pistons
themselves, which open and close the ports. Specifically, each
power cylinder is provided with an inlet port 40 and an outlet or
exhaust port 42. The inlet ports of the several power cylinders are
connected to the air charging cylinders by means of suitable tubes,
as will shortly be described. The outlet or exhaust ports are
connected to an exhaust manifold and exhaust pipe, neither of which
is shown in the drawing because it is entirely conventional.
It will be noted that the inlet ports 40 are of smaller diameter
than the outlet or exhaust ports 42. In the preferred form of this
invention, the inlet and outlet ports are not coaxial, but they do
register with each other to the extent of the diameter of the inlet
ports. When a power piston reaches its extreme outermost position
relative to the cylinder in which it is housed, as for example
piston 10d in cylinder 10a, as shown in FIG. 7, both ports 40 and
42 are fully open. When the piston occupies a less extreme outer
position, as does piston 10d in cylinder 10a in FIG. 11, inlet port
40 is closed while outlet port 42 is partly open and partly closed.
Depending upon the direction of movement of the piston relative to
these two ports, outlet port 42 may first open and then inlet port
40, or inlet port 40 may first close and then outlet port 42.
The significance of this opening and closing sequence is the
following: When a power piston, e.g., power piston 10d, moves
outwardly in its power stroke, outlet port 42 first opens to allow
the combustion gases to escape. This occurs immediately before the
piston reaches its outermost position relative to the cylinder in
which it is disposed. By the time the outermost position is
reached, inlet port also opens, and this enables an inward rush of
air to scavenge the cylinder and thereby drive the remaining
combustion gases out of the cylinder through outlet port 42. The
combustion gases are thereby replaced by a fresh charge of air or
air-fuel mixture, as the case may be. When the piston now reverses
its stroke and moves inwardly relative to the cylinder in which it
is mounted, inlet port 40 closes, thereby shutting off the supply
of air or air-fuel mixture. Further inward movement of the piston
closes the outlet port, and the fresh charge of air or air-fuel
mixture may now be compressed. This sequence and the functional
relationship between the power and air charging cylinders will
shortly be discussed in greater detail to describe the functioning
of the entire engine.
In the two-cycle engine which is illustrated in the drawing, the
function of the air charging cylinders is to scavenge and recharge
the power cylinders. It will be observed that each air charging
cylinder has an inlet port 44 and an outlet port 46. The inlet port
communicates with the atmosphere to receive air, or with a
carburetor to receive an air-fuel mixture. A check valve 48 is
provided at inlet port 44 in order to allow air or an air-fuel
mixture to enter the air charging cylinder and said check valve
automatically closes to prevent discharge of the air or air-fuel
mixture from said cylinder. A second check valve 50 is provided at
outlet port 46, and its function is to allow the air or air-fuel
mixture to leave the cylinder, and it automatically closes to
prevent a reverse flow through outlet port 46 when the air charging
cylinder is in process of receiving a fresh charge of air or
air-fuel mixture. It will be understood (and it will be seen in the
drawing, e.g., in FIG. 1) that each air charging cylinder is
connected to two power cylinders. Accordingly, it is desirable to
provide a Y-type fitting at the outlet port 46 of each air charging
cylinder, the two branches of the Y-fitting being connected by
suitable tubing to the two power cylinders with which each air
charging cylinder is associated. The relationship between the
several air charging cylinders on the one hand and power cylinders
on the other, and the air lines between the two groups of
cylinders, are shown pictorially in FIG. 1 of the drawing and
schematically in FIGS. 12, 13, 14, 15 and 16. In FIG. 1, as well as
in FIGS. 12 through 16, it is shown that air charging cylinder 10c
is connected by means of air lines 60a and 60b to power cylinders
14a and 16b , respectively. It is similarly shown that air charging
cylinder 12c is connected by means of air lines 62a and 62b to
power cylinders 16a and 14b, respectively. Air charging cylinder
14c is connected by means of air lines 64a and 64b to power
cylinders 12a and 10b, respectively. And finally, air charging
cylinder 16c is connected by means of air lines 66a and 66b to
power cylinders 10a and 12b, respectively. It is of course
understood that these several air lines are connected between the
outlet ports 46 of the air charging cylinders and the inlet ports
40 of the power cylinders. Accordingly, each air charging cylinder
is connected to and is responsible for the scavenging and
recharging of two power cylinders.
It will also be understood that the power cylinders require not
only air but also fuel and means for igniting the air-fuel mixture.
If the engine which embodies the present invention is a gasoline
fuel internal combustion engine, it has one or more carburetors or
other air-fuel mixing and feeding devices. Assuming the existence
and use of a carburetor, it will be understood that it is connected
to the several air charging cylinders and that they supply the
power cylinders with an air-fuel mixture. Ignition would require
the use of spark plugs 66. On the other hand, if the invention is
embodied in a diesel engine, the air charging cylinders would
supply only air to the power cylinders, and fuel would be injected
into said power cylinders by means of fuel injectors 68.
It will also be understood, and it is clearly shown in the drawing,
that the air charging cylinder which is mechanically connected to a
given pair of power cylinders is not connected to those particular
power cylinders for air supply. As an illustration, FIG. 7 shows a
pair of power cylinders 10a and 10b and an air charging cylinder
10c mechanically connected to said power cylinders through their
respective pistons and piston rods. However, air charging cylinder
10c does not supply air to power cylinders 10a and 10b. Instead, as
has above been indicated and as is shown in FIG. 1 and FIGS. 12 to
16, inclusive, air charging cylinder 10c is connected by air lines
60a and 60b to power cylinders 16a and 14b.
The mechanical operations of a representative pair of power
cylinders and the air charging cylinder which is mechanically
associated therewith will now be described. FIGS. 7, 8, 9, 10 and
11 depict the various stages in a cycle involving the pistons and
piston rods of power cylinders 10a and 10b and air charging
cylinder 10c. In all of these figures the crankshaft rotates in
counterclockwise direction, as indicated by curved arrows 70.
Starting with FIG. 7, it will be noted that power piston 10d is at
its extreme outer position following a power stroke and power
piston 10f is at its innermost position following a compression
stroke. Ports 40 and 42 in cylinder 10a are now open, so that the
combustion gases may escape through the outlet port 42 and the
fresh charge of air may enter through inlet port 40. The inrush of
fresh air completes the evacuation of combustion gases and fills
the cylinder. At the same time, the air or air-fuel mixture within
power cylinder 10b is compressed preparatory to a power stroke of
piston 10f. Ignition occurs, e.g., by the use of spark plug 66, and
an explosion takes place within power cylinder 10b.
In the meantime, piston 10h in air charging cylinder 10c is moving
upwardly, and is thereby expelling air from said air charging
cylinder through open valve 50 and driving it into power cylinders
16a and 14b.
The next stage in the operation is shown in FIG. 8. Pistons 10d and
10f now move leftwardly, an explosion having taken place in
cylinder 10b driving piston 10f outwardly therefrom and compression
taking place concurrently therewith in cylinder 10a. Air charging
piston 10h has now moved to its extreme uppermost position in
cylinder 10c, and this marks the end of its air charging operation
with respect to power cylinders 16a and 14b.
The next stage in the operation is shown in FIG. 9, wherein power
piston 10d has reached its extreme inward position in cylinder 10a
and power piston 10f has reached its outermost position in cylinder
10b. This is the reverse of their respective positions as shown in
FIG. 7. The outlet port 42 of cylinder 10b is opened first to start
the exhaust of the combustion gases from said cylinder, and inlet
port 40 then opens to receive a fresh charge of air from air
charging cylinder 14c. As has above been indicated, the inrush of
fresh air completes the process of exhausting the combustion gases
and the fresh air accordingly takes the place of the combustion
gases in power cylinder 10b. On the opposed side power piston 10d
has reached its innermost position wherein it compresses the air in
cylinder 10a. Since it is assumed that a carburetor is being used,
a suitable charge of fuel is entrained with the air, and what is
compressed in cylinder 10a is a combustible air-fuel mixture.
At the same time piston 10h moves downwardly in air charging
cylinder 10c, and it is thereby drawing a fresh charge of air into
said cylinder through open valve 48.
The next stage in the operation is shown in FIG. 10, wherein the
power pistons are depicted moving rightwardly. Specifically,
combustion has started in power cylinder 10a, driving piston 10d
outwardly therefrom and forcing piston 10f inwardly relative to
cylinder 10b. Since cylinder 10b has received a charge of fresh air
entrained with fuel, piston 10f is now in the process of
compressing same into an explosive mixture. Piston 10h has now
reached its outermost position in cylinder 10c, and it has drawn a
full charge of air, entrained with fuel, into said cylinder.
Cylinder 10c is now ready to deliver a fresh charge of air and fuel
to the power cylinders 16a and 14b with which it is connected.
FIG. 11 depicts the next stage in the operation, just short of the
starting stage shown in FIG. 7. The expansion of the combustion
gases in cylinder 10a continues to drive power cylinder 10d
outwardly, but it has not yet reached its outermost position shown
in FIG. 7. By the same token, piston 10 f is moving toward its
extreme innermost position in cylinder 10b, but it is still short
of the starting position which is shown in FIG. 7. More
particularly, piston 10d has moved outwardly a sufficient distance
to partially open the outlet port 42 in cylinder 10a, but inlet
port 40 in said cylinder remains closed. Accordingly, the
combustion gases in cylinder 10a begin to exhaust out of said
cylinder, but they are not yet being forced out of the cylinder by
the inrush of a new charge of air. On the opposite side piston 10f
is compressing the air-fuel mixture in cylinder 10b, but
compression has not yet been completed.
Piston 10h is again moving upwardly in air charging cylinder 10c,
and it is driving air entrained with fuel out of said cylinder
through open valve 50 and into cylinders 16a and 14b. The final
stage in the operation is the same as the initial stage depicted in
FIG. 7. One complete cycle has now been concluded, and the next
cycle is about to begin.
The relationship among the several air charging cylinders and the
manner in which their respective piston rods operate upon the
crankshaft may be seen in FIGS. 2, 3, 4, 5 and 6. These figures
coincide with FIGS. 7, 8, 9, 10 and 11 in the sense that the
several stages of the pistons shown in FIGS. 7, 8, 9, 10 and 11
correspond identically to their stages in FIGS. 2, 3, 4, 5 and
6.
Turning now to FIG. 2, it will be seen that piston 10h occupies the
same position in air charging cylinder 10c in that figure which it
does in FIG. 7. Similarly, piston 10h occupies the same position in
FIG. 3 which it does in FIG. 8, the same position in FIG. 4 which
it occupies in FIG. 9, the same position in FIG. 5 which it
occupies in FIG. 10, and the same position in FIG. 6 which it
occupies in FIG. 11. By the same token, power pistons 10d and 10f
occupy the same positions in their respective cylinders 10a and 10b
in FIG. 7 which they occupy in FIG. 12, the same positions in FIG.
8 which they occupy in FIG. 13, the same positions in FIG. 9 which
they occupy in FIG. 14, the same positions in FIG. 10 which they
occupy in FIG. 15, and the same positions in FIG. 11 which they
occupy in FIG. 16. It will similarly be understood that FIGS. 2
through 6 are vertical sections (at least in part) of FIGS. 12
through 16. Consequently, the relative positions of all of the
pistons shown or indicated in FIGS. 2 through 6 correspond to the
relative positions of the same pistons in FIGS. 12 through 16.
Selecting FIG. 2 for illustrative purposes, it will be seen that
piston 10h occupies the same position in cylinder 10c of FIG. 2
which it occupies in FIG. 7, piston 12h occupies the same position
in cylinder 12c of FIG. 2 which it occupies in FIG. 9, piston 14h
occupies the same position in cylinder 14c of FIG. 2 which it
occupies in FIG. 10, and piston 16h occupies the same position in
cylinder 16c of FIG. 2 which it occupies in FIG. 8. The same may be
said of FIGS. 3 through 6. Each of the pistons of each of the air
charging cylinders shown in FIGS. 3 through 6 is shown in a
position which corresponds to one of the positions shown in FIGS. 7
through 11.
The operation of the engine may best be understood from FIGS. 12
through 16 and their corresponding vertical sections shown in FIGS.
2 through 6.
Turning now to FIG. 12, it will be understood that power cylinders
10a and 12b are shown receiving a charge of air entrained with
fuel, from air charging cylinder 16c. This is evidenced by heavy
lines 66a and 66b and the arrowheads which are superimposed upon
them. This process completes the exhaustion of the combustion gases
from said cylinders and recharges them with an air-fuel mixture
preparatory to the combustion stroke.
Concurrently with the air charging operation last described, the
compressed air-fuel mixture in cylinder 12a ignites and commences
to burn to begin the power stroke of the piston in that cylinder.
This is equally true of the compressed air-fuel mixture in cylinder
10b, and the ignition of this mixture commences the power stroke of
the piston in that cylinder. It will therefore be observed that
since the pistons in cylinders 10a and 10b are opposed and
connected through their respective piston rods, and since the
pistons in cylinders 12a and 12b are also opposed, the last
described power strokes commencing in cylinders 12a and 10b will
produce compression strokes in cylinders 12b and 10a.
Also concurrently with the foregoing expansion of the combustion
gases in cylinders 14a and 16b causes compression of the air-fuel
mixtures in cylinders 14b and 16a. The direction of movement of the
several pistons in FIG. 12 is shown by the arrows which relate to
them.
FIG. 13 represents the next phase in the operation of the engine.
In this figure cylinders 14a and 16b are shown receiving a charge
of air entrained with fuel, and once again the inrush of this flow
completes exhaustion of the combustion gases of the prior power
stroke and introduces into the cylinders a fresh charge of such
air-fuel mixture. At the same time, the compressed air-fuel mixture
in cylinders 14b and 16a ignites, and the expanding combustion
gases begin the power strokes of the pistons in those cylinders.
Also concurrently therewith, the expanding combustion gases in
cylinders 10a and 12b continue the power strokes of the pistons in
those cylinders and produce compression strokes of the pistons in
cylinders 10b and 12a.
FIG. 14 shows the next stage in the operation of the engine.
Cylinders 10b and 12a are shown receiving a fresh charge of an
air-fuel mixture and the compressed air-fuel charges in cylinders
10a and 12b are now ignited in said cylinders to begin the power
stroke of the pistons therein. Such power stroke will of course
result in compression of the fresh charges in cylinders 10b and
12a. Concurrently with the foregoing, the expanding combustion
gases in cylinders 14b and 16a are producing a power stroke of the
pistons in those cylinders, resulting in compression strokes of the
pistons in cylinders 14a and 16b.
The next stage in the operation of the engine is shown in FIG. 15.
Here fresh charges of air entrained with fuel are entering
cylinders 14b and 16a, while the compressed charges in cylinders
14a and 16b are igniting to begin the power stroke of the pistons
in said cylinders 14a and 16b. As has above been indicated, this
will produce compression strokes of the pistons in cylinders 14b
and 16a. Concurrently therewith, the power stroke of the pistons in
cylinders 10b and 12a is proceeding, as is the compression stroke
of the pistons in opposed cylinders 10a and 12b.
FIG. 16 shows the next stage in the operation of the engine,
wherein the pistons in cylinders 10a and 12b are shown approaching,
but not reaching, the end of their respective power strokes. The
exhaust ports have been opened, but not the inlet ports.
Accordingly, the combustion gases are now escaping from these
cylinders, but they are not fully expelled therefrom until the
pistons reach the end of their power stroke and thereby open the
inlet ports to admit a fresh charge of air entrained with fuel. It
is this fresh charge that fully exhaust these two cylinders of
their combustion gases. The pistons in opposed cylinders 10b and
12a are concurrently approaching, but not reaching, the end of
their compression stroke. Also, the power stroke of the pistons in
cylinders 14a and 16b is continuing, while the compression stroke
of the pistons in cylinders 14b and 16a is concurrently proceeding.
When the pistons 10a and 12b reach the end of their power stroke,
they and all of the other pistons shown in FIG. 16 will occupy the
same relative positions as they are shown to occupy in FIG. 12,
thereby concluding one complete cycle and commencing the next.
It will be seen, particularly in FIGS. 7 through 10 of the drawing,
that the crankshaft is shown in four successive angular positions,
spaced 90.degree. apart. At each angular position of the crankshaft
two of the eight power cylinders are engaged in their respective
power strokes. It follows that, for every revolution of the
crankshaft, four separate and successive power thrusts are
delivered to it, each delivered by two separate and spaced power
pistons situated 180 .degree. apart. This arrangement makes for a
nicely balanced engine with smooth operation and a substantially
continuous flow of power.
The relatively long stroke--small bore design provides a relatively
high torque output at a relatively low r.p.m. The length of the
power piston stroke is twice the length of the crankshaft throw
(diameter of the circular path described by the crankpins). This is
effected through the use of the piston rod of the air charging
cylinder as a lever between the piston rods of the power cylinders
and the crankshaft. Accordingly, the power pistons apply twice the
leverage upon the crankshaft which they would apply if connected
directly thereto. This is clearly apparent from FIGS. 7 through 11
of the drawing.
The long stroke small bore design also provides an improved surface
(piston area) to cylinder volume ratio which, when combined with
the longer piston dwell during initial combustion stages, lengthens
time in milliseconds before quenching begins, to promote more
complete combustion during the work stroke.
This will be evident from a study of FIGS. 7 through 11 of the
drawing. It will there be seen that opposed power pistons 10d and
10f are not always the same distance apart. When their respective
piston rods 10e and 10g are axially aligned, as in FIGS. 7 and 9,
the pistons are at their extreme outer positions relative to each
other. When these piston rods are inclined toward each other at the
smallest angle which the geometry of the system will permit, as in
FIGS. 8 and 10, the pistons are at their extreme inner positions
relative to each other.
It will also be understood that these opposed power pistons travel
toward and away from each other concurrently with their joint
movement in the same direction. Thus, when the crankshaft rotates
90.degree. from its FIG. 7 to its FIG. 8 position, the power
pistons will move toward each other at the same time that they are
both moving leftwardly. Stated differently, power piston 10d will
move leftwardly at a slower speed than piston 10f, so that in
relation to each other the two pistons will be moving toward each
other.
By the same token, when the crankshaft rotates an additional 90
.degree., this time from its FIG. 8 to its FIG. 9 position, the two
power pistons 10d and 10f will move away from each other
concurrently with their continued joint movement leftwardly. When
the crankshaft rotates a further 90 .degree. from its FIG. 9 to its
FIG. 10 position, the power pistons 10d and 10f will move toward
each other at the same time that they are both moving rightwardly.
When the crankshaft rotates an additional 90 .degree. from its FIG.
10 to its FIG. 7 position, completing a 360 .degree. revolution,
the said power pistons will move away from each other concurrently
with their joint continued movement toward the right.
As has above been indicated, one of the consequences of this
relationship between the power pistons is that longer piston dwell
is attained during initial combustion stages and hence more
complete combustion.
The foregoing is illustrative of a preferred form of the invention,
and it will of course be understood that the invention encompasses
extensive design modifications within the broad scope of the
appended claims. For example, what is shown is an air-cooled engine
with fins 24 serving as heat exchangers for the power cylinders and
fins 72 serving as heat exchangers for the air charging cylinders.
Obviously the invention is equally applicable to a liquid-cooled
engine. Similarily, the power pistons are shown formed with a
protuberance 74 for enhanced distribution of the air-fuel mixture
and more uniform combustion thereof. Clearly, modifications in this
design, and even the omission of any such protuberance, would fall
within the range and scope of the principles of this invention and
the appended claims. Nor is the invention limited to the particular
dimensions and proportions shown in the drawing. This is
particularly true of the stroke-bore ratio and the lever ratios
shown in the drawing.
* * * * *