Reed valve mechanism for engines

Reed valve mechanism for use in the fuel/air supply system of an internal combustion engine, the mechanism including passages, ports and reed valves, all of which are arranged to minimize unnecessary fluctuations of the flow velocity of the fuel/air being delivered to and into the cylinder of an engine and also minimize localized turbulence in the flow path and thereby increase the power output of the engine.

BACKGROUND AND STATEMENT OF OBJECTS 
In my prior U.S. Pat. Nos. 4,228,770, issued Oct. 21, 1980, and 4,474,145 
issued Oct. 2, 1984, there are disclosed various forms of fuel supply 
systems particularly adapted for use in internal combustion engines, 
especially two-cycle engines of the kind extensively employed in 
motorcycles and also in various industrial equipment, including power 
saws. 
In many of such two-cycle engines, the fuel/air supply system includes a 
supply passage approaching the inlet opening in the cylinder wall, and 
further includes at least one ported wall positioned in a plane transverse 
to and usually obliquely inclined with respect to the axis of flow through 
the fuel/air supply passage. Quite commonly, a V-shaped reed cage is 
employed in such fuel supply systems, as is disclosed in my prior U.S. 
patents referred to above and also in the present application, the reed 
cage having a pair of inclined converging side walls joined in a reed cage 
apex presented downstream of the axis of flow through the supply passage. 
Reed valves are provided overlying the valve ports in the inclined ported 
walls. Although the reed cage may be positioned with its apex extended in 
various directions, it is preferred that the apex be generally horizontal 
as shown in various embodiments illustrated. 
In fuel supply and valve arrangements of the kind referred to, in order to 
maintain maximum power output of the engine, especially at high operating 
speeds, it is of great importance to minimize fluctuations in the velocity 
of flow through the fuel/air supply system and through the valves and into 
the cylinder. Some appreciable reduction of fluctuations in the velocity 
of flow is provided in my prior U.S. patents above referred to by the 
provision of an interior element in the flow passage upstream of the valve 
ports, such element having an aerodynamic or airfoil contour so that 
velocity fluctuations in the fuel/air flow at and near the surfaces of the 
aeroform element are reduced, particularly at high engine speeds. 
It is also of importance to minimize abrupt changes in the direction of 
flow of the fuel/air through the intake system and the valves and into the 
intake port of the engine, thereby minimizing fuel/air drag as the 
fuel/air flows through the intake system. Still further, it is of 
importance to avoid localized turbulence in various regions of the flow or 
supply passage. 
The foregoing and other objectives of the present invention are 
accomplished by introducing a number of changes in the structure, contours 
and arrangements of the parts defining the flow passage at various regions 
along the flow path. 
Some of the foregoing objectives are achieved by providing curvilinear 
surfaces surrounding the fuel/air flow passage or passages within the reed 
cage, such surrounding surfaces being of aerodynamic or airfoil contour 
within the reed cage and thereby minimizing flow velocity changes and 
providing for extensive reduction in turbulence at the perimeter of the 
flow passages within the reed cage as such passages merge with the 
portions of the port under the side edges and under the delivery end edge 
of the valve reed. 
The passages through the reed cage are also arranged so as to avoid abrupt 
changes in the direction of flow within the reed cage. 
As will further be seen, in certain embodiments of the present invention, 
provision is made not only for reducing the velocity fluctuations around 
the perimeter of the air/fuel flow stream, but this feature of the present 
invention may, in some embodiments, also be employed in combination with 
an aeroform element positioned within the passage in the reed cage similar 
to interior elements of the kind disclosed in my prior U.S. patents above 
identified, and this combination results not only in particularly 
effective reduction in velocity fluctuations but also in great reduction 
in turbulence. 
Certain embodiments of the present invention further include a specially 
formed cavity in the engine housing for receiving the reed cage in the 
region of the inlet port through which the fuel/air is delivered from the 
reed cage. This cavity includes additional fuel/air passageways at the 
ends of the reed cage, formed in the engine housing structure beyond the 
end walls of the V-shaped reed cage. Such additional passages at each end 
of the reed cage generally parallel the adjacent inclined surface of the 
reed cage and are interconnected with a cavity or passageway formed in the 
engine housing structure beyond the reed cage apex and leading to the 
engine intake/porting. These additional external passages lie beyond each 
end of the reed cage and not only communicate with each other but also 
communicate with the fuel/air flow path downstream of the reed cage apex 
and thus also with the intake porting into the engine. All of these 
additional passages are preferably also of curvilinear contour in order to 
minimize abrupt changes in the flow path of the incoming fuel/air when the 
reed valves open the valve ports in the reed cage. In this way, portions 
of the fuel/air delivered from the valve ports at the end regions of the 
reed cage apex may spread laterally into passages of aeroform contour 
merging downstream of the apex and ultimately entering the intake porting 
in the engine housing structure. 
The foregoing is particularly effective in minimizing the undesirable type 
of turbulence which frequently results from impingement of a fuel/air 
stream against a surface which is planar, rather than curvilinear. 
In considering various aspects of the present invention, it should be kept 
in mind that in the operation of the engine at any speed, the flow of the 
fuel/air into the cylinder necessarily starts and stops with each cycle of 
the engine regardless of the speed of operation. However, the contours of 
the surfaces defining the flow passages extensively influence the 
character of the starts and stops of the flow. Flat surface areas 
perpendicular to the flow axis accentuate turbulence and unnecessarily 
increases kinetic energy loss when the flow starts and stops. 
The flow passage arrangements provided according to the present invention 
are used in combination with certain valve porting and reed valve 
arrangements which also reduce turbulence and fluctuation of flow velocity 
in the flow path. 
Unnecessary turbulence and secondary velocity fluctuations of the fuel/air 
flow tend to reduce the power output of the engine, in part, because of 
the waste of energy involved in unnecessary velocity changes. The fuel/air 
stream has kinetic energy, and increase or decrease of the flow velocity 
results in loss of kinetic energy, and at any speed of operation of the 
engine, unnecessary fluctuations of velocity results in substantial energy 
loss. Avoiding rapid fluctuations of the flow velocity also diminishes 
turbulence in areas where the flow path is required to shift in direction, 
and this further reduces waste of energy in engine operation.

DETAILED DESCRIPTION OF THE DRAWINGS 
FIGS. 1 to 5 
As best seen in FIGS. 2, 3 and 4, a typical engine housing or structure 
includes a cylinder casting 12 associated with a crankcase casting 13. The 
cylinder itself is defined by a cylinder liner 14 as is customarily 
employed and the piston 15 reciprocates in the cylindrical chamber formed 
within the cylinder liner 14. The piston has the usual connecting rod 16 
projecting downwardly for association with a crank (not shown) on the 
crankshaft of the engine. The crankshaft (not shown) may be centered at 
the point indicated at 17. A counterweight of conventional form may also 
be associated with the crankshaft. The connecting rod is, of course, 
coupled with the piston by means of the wrist pin 18. Heat radiating fins 
19 may also be provided externally of the cylinder. 
A fuel/air intake passage or port is provided in the region 20 in the lower 
part of the side wall of the cylinder and extended intake porting 20a 
communicates with the space below the piston even in bottom dead center 
position. The fuel supply system delivers fuel/air to the porting 20 and 
20a in the manner more fully explained hereinafter with reference to the 
valve mechanism provided according to the present invention. 
An exhaust passage 21 is provided in a position generally diametrically 
opposite to the intake passage 20, this exhaust passage having an exhaust 
port 22 through the cylinder wall and cylinder liner and entering the 
combustion chamber above the piston when the piston is in bottom dead 
center position, which is the position illustrated in FIG. 2. 
Primary transfer passages are also provided, one of which is indicated at 
23, this passage having a transfer or delivery port 24 into the cylinder 
above the piston when the piston is in bottom dead center position, as in 
FIG. 2, and further having an entrance port 25 positioned to remain 
uncovered below the level of the piston skirt even when the piston is in 
bottom dead center position, as in FIG. 2. Supplemental passages, such as 
indicated at 23a, are also connected with the primary transfer passages 23 
and are connected with the intake porting 20, as is shown in FIGS. 2 and 
3. It should also be noted that the skirt of the piston is cut off at 
least in the area indicated at 26 so that even in bottom dead center 
position, the extended intake porting 20a remains open. When the piston 
rises in the cylinder sufficiently to uncover the port 20, communication 
is also provided from the fuel/air intake port 20 radially inwardly and 
downwardly into the space below the piston and the adjoining crankcase 
volume. 
Because of the arrangements described above, when the piston 15 rises, the 
resultant suction or decrease in pressure in the crankcase region results 
in the drawing in of fuel/air through the intake port 20 and the extended 
porting 20a into the space below the piston. This suction continues until 
the piston substantially reaches its top dead center position. The top 
wall of the cylinder is not illustrated in the drawings, but its location 
and configuration are well understood in this art. The top wall is 
customarily located just above the top of the combustion chamber 
illustrated in FIG. 2, and the upward stroke of the piston brings the top 
of the piston substantially to the top of the cylinder structure shown in 
FIG. 2. When the piston rises in the cylinder, above the transfer port 24, 
the transfer passage 23 in the cylinder wall is closed. The exhaust 
passage 21 is also closed when the port 22 is covered by the piston. 
When the piston descends, the charge of fuel/air which was introduced into 
the crankcase chamber or space below the piston during the preceding 
upward stroke of the piston is compressed in the space below the piston by 
the closing of the reed valves. This compression of the charge continues 
until the transfer port 24 at the upper end of the transfer passage 23 is 
opened by the descent of the piston, and at that time, the fuel/air 
compressed below the piston is delivered upwardly through the transfer 
passage 23 into the combustion chamber above the piston. 
Each upward stroke of the piston compresses a charge of fuel/air in the 
combustion chamber above the piston head, and at the top of the stroke, as 
is customary and well known in this art, the compressed charge is ignited, 
with resultant explosion which drives the piston down again and also 
results in exhaust of products of combustion through the exhaust port 22 
and the exhaust passage 21. 
The embodiment illustrated in FIG. 2 also includes an auxiliary transfer 
passage 27 having a port 28 in the cylinder wall and interconnecting the 
fuel intake chamber 29 with the space above the piston. 
The arrangement and functioning of the parts described above with reference 
to the two-cycle engine, including the cylinder, piston, intake chamber 29 
with the intake port 20, and also with other parts pointed out including 
the main transfer passage 23, the supplemental passage 23a, the exhaust 
passage 21 and the auxiliary transfer passage 27, is well understood in 
the two-cycle engine art, including the two U.S. patents referred to 
herein. 
The present invention is particularly concerned with a novel form of the 
intake valve mechanism or structure provided for introducing the fuel/air 
from a carburetor or other appropriate source into the intake chamber 29 
and thus into the various ports and passages associated with the intake 
chamber and ultimately into the combustion chamber. 
In many prior art arrangements, the intake valve mechanism is associated 
with what is known as a reed cage, and the present invention provides a 
novel form of reed cage, this structure being shown in perspective in FIG. 
1, and also shown in vertical section in FIG. 2. The reed cage appears in 
FIG. 3 partly in horizontal section and partly in elevation. The reed cage 
is generally indicated in FIG. 1 by the numeral 30, the reed cage having a 
mounting plate 31 adapted to be connected to the cylinder structure 12 by 
means of attachment screws 32. The body of the reed cage is of V-shaped 
configuration having a pair of obliquely inclined walls 33, meeting at an 
apex 34. The reed cage also has external end walls 35 and a central wall 
36 dividing the space within the reed cage into two channels which merge 
or join at the upstream end in a common passage or duct 37. Fuel is 
adapted to be supplied into the common duct 37 through the fuel supply 
connection 38 adapted to be associated with the carburetor supply line 39. 
From the above, it will be seen that the supply line from the carburetor 
extends into the interior of the V-shaped reed cage and is divided between 
the two interior channels formed at the sides of the central wall or 
partition 36. 
The inclined walls 33 of the reed cage are each provided with a pair of 
primary valve ports 40 located at each side of the central wall or 
partition 36 (see particularly FIGS. 1 and 3). It will thus be understood 
that there are two ports 40 through each of the inclined reed cage walls 
at opposite sides of the reed cage. 
The invention contemplates employment of flexible reed valves overlying the 
supply ports and in the preferred embodiment according to the invention, a 
single primary reed valve 41 is provided for the pair of intake ports 40 
at each side of the reed cage. 
The common primary reed valve 41 at each side of the reed cage is 
preferably provided with a plurality of secondary valve ports 42, two 
secondary ports being used in the embodiment of FIGS. 1 to 5; and a 
separate secondary reed valve 43 is provided for each one of the secondary 
ports 42. Each of the secondary reeds may be individually opened and 
closed under the action of the intake during operation of the engine. 
However, all four of the secondary reeds are preferably joined together at 
the base ends for convenience in manufacture and assembly. Moreover, both 
the primary and secondary reeds may be mounted in common at each inclined 
face of the reed cage by means of a fastening strip 44 connected to the 
reed cage by means of a series of attachment screws 45. 
From FIGS. 1 and 2, it will also be seen that the attachment of the reed 
valves to the inclined reed cage walls is arranged along the base edges of 
the inclined walls of the reed cage. 
The reed valves may be formed of a variety of materials, but preferably the 
reed valves are formed of resin material, the epoxy type of resins having 
glass fiber reinforcement being particularly effective for this purpose in 
two-cycle engines. The valve reeds preferably have a high modulus of 
elasticity and in a typical case, such as glass fiber reinforced epoxy 
resin, the resin should be heat-resistant up to about 350.degree. F. and 
have a modulus of elasticity of the order of from 2,000,000 to 2,700,000. 
In the preferred embodiment of the valve reeds, the primary valve reeds are 
preferably stiffer and thicker than the secondary reeds. Thus, the primary 
reeds may have a thickness of from about 0.018" to about 0.030", and the 
secondary reeds may have a thickness of from about 0.012" to about 0.020". 
The secondary valve ports 42 and also the secondary valve reeds 43 are 
preferably respectively shorter than the primary ports 40 and the 
overlying portions of the primary valve reeds 41. In this way, the flow 
passage through the primary valve ports is larger than the flow passage 
through the overlying secondary valve ports. This relationship aids in 
establishing desirable relative timing of the opening and closing of the 
secondary and primary valve reeds at various speeds of engine operation. 
The foregoing general arrangement of primary and secondary reeds 
contributes to efficient operation of the engine, particularly where, as 
is contemplated according to the present invention, the interior channels 
or passages through the reed cage to the primary reed ports are defined by 
side walls of curved or aeroform shape. Thus, the interior surfaces of the 
end walls of the reed cage defining portions of the flow channels or 
passages are of aeroform contour with respect to the axis of flow through 
the supply passage to the valve ports. The interior aeroform surfaces 
referred to are curved so as to lie closer to the flow axis in the 
upstream portion of the flow passage as compared with the downstream 
portion of the flow passage, as clearly appears in FIG. 3. These curved or 
aeroform surfaces appear in various figures and are identified by the 
reference numeral 46 in FIG. 3. Similarly contoured surfaces are provided 
at the opposite sides of the central wall or partition 36, such surfaces 
being identified by the numeral 47 in FIGS. 3 and 4. 
The contours of the aeroform surfaces referred to provide for power 
increase of the engine at various speeds and various throttle settings. 
One of the reasons why these contours provide for an increase in the power 
output of the engine lies in the fact that the contours herein disclosed 
reduce unnecessary velocity changes and minimize turbulence and 
aerodynamic drag in the flow of the fuel/air entering the engine. The 
curvilinear shape of the walls defining the flow channels, particularly in 
the region of the downstream ends of the reed valves and the underlying 
ports results in improvement in power output because of extensive decrease 
in both aerodynamic drag and also localized turbulence in the flow path. 
This is especially true under the lower or free edges of the reed valves, 
and the laterally adjoining surfaces of the valve ports, because these are 
the regions where the highest velocity flow occurs in the flow through the 
valve mechanism. The power output of the engine is substantially increased 
under various operating conditions, as a result of these arrangements. 
From FIGS. 1 and 2 it will also be noted that the apex member 34 of the 
reed cage is also of aeroform crosssectional shape, and this is of 
particular significance in the power output of the engine at high engine 
speeds. The aeroform cross-sectional shape of the apex member provides 
curved surfaces presented toward both sides of the reed cage, and these 
curved surfaces minimize local turbulence in the zones where the fuel/air 
flow is passing from the flow channels within the reed cage over the 
surfaces of the apex member and into the intake port 20. 
The somewhat schematic illustration of FIG. 5 serves also to indicate the 
minimization of turbulence occurring in the input of fuel/air in a system 
according to the present invention From FIG. 5, it will be seen that the 
sectional area of the flow channels does not abruptly change as the flow 
progresses from the carburetor supply line 39 to the intake port 20 The 
curvilinear surfaces indicated in FIG. 5 are also of effect in minimizing 
changes in the cross section of the flow passages and in minimizing 
aerodynamic drag, particularly in the downstream region of the flow path 
from which the fuel is delivered from the open reed valves into the intake 
port 20 of the engine. 
FIGS. 6 to 10 
In the second embodiment illustrated in these figures, the general 
arrangement of the engine itself is the same as in the first embodiment, 
and the reference characters used to identify the various engine, cylinder 
and piston parts have been applied to FIGS. 7, 8 and 9 in the same manner 
as in FIGS. 2, 3 and 4. Repetition of these portions of the description is 
not necessary in view of the description above in connection with the 
first embodiment. 
In the second embodiment, the arrangement and contours of the reed cage and 
the reed valve is different from the first embodiment, but in the second 
embodiment, as in the first embodiment, provision has been made for the 
employment of aeroform or curvilinear surfaces in various passages in 
order to reduce kinetic energy losses encountered in prior art 
arrangements and also in order to minimize localized turbulence and 
aerodynamic drag, both of these factors being of importance in maximizing 
the power output of the engine 
The reed cage as shown in the second embodiment includes a base or mounting 
plate 48 having apertures 49 for receiving fastening screws 50 by which 
the reed cage and valve assembly is mounted at the side of the engine 
cylinder 12. 
As in the first embodiment, the reed cage is provided with a supply duct 51 
adapted to be associated with the supply line 39 by means of the 
connection 38. 
As in the reed cage of the first embodiment, the reed cage of the second 
embodiment is also formed with external end walls 52 and with a pair of 
obliquely inclined side walls 53 which are connected with the base plate 
48 and which are joined at the reed cage apex by means of an apex member 
54, thereby forming a V-shaped reed cage. 
The interior of the reed cage is formed with curved surfaces 55 which 
provide three side-by-side interconnected flow channels at the inner side 
of each of the inclined walls 53 as those walls approach the apex 54. This 
distinguishes from the first embodiment in which the interior of the reed 
cage is divided into two separated channels, as above fully described. In 
the second embodiment, the interior partially separated channels terminate 
in three partially separated primary valve port areas as clearly appears 
toward the bottom of FIG. 6, the outer two of which are identified by the 
reference numeral 56 and the central one of which is identified by the 
numeral 57 (see particularly FIGS. 6 and 8). As will be understood from 
the drawings, this multi-channel arrangement is provided at both sides of 
the reed cage, interiorly of the two inclined walls 53. 
As in the first embodiment, the second embodiment is provided with both 
primary and secondary reed valves and these may be formed of the same type 
of materials as described above, but the arrangement is somewhat different 
because of the differences in the portage of the reed cage. While the reed 
cage of FIG. 6 is illustrated in the same perspective position as the reed 
cage in FIG. 1, the reed valves in FIG. 1 are illustrated (in part broken 
away) in positions as applied to the inclined walls of the reed cage, 
whereas in FIG. 6 the reed valves are shown in "exploded" relation to the 
reed cage. 
The reed valves of the second embodiment include a primary reed valve 
structure 58 having three secondary valve ports 59 therein. The secondary 
reeds cooperating with the secondary ports 59 are indicated at 60, the 
secondary reeds being interconnected at the base or mounting ends and both 
the primary and the secondary reeds being adapted to be fastened to the 
reed cage, preferably by means of a common mounting strip 61 and mounting 
screws 62. 
From the drawings, it will be clear that when these reed valves 58 and 60 
are assembled and mounted upon the inclined walls of the reed cage, the 
primary reed valve structure 58 will overlie the primary ports 56-56 and 
57, with the secondary valve ports 59 respectively positioned in alignment 
with the primary ports 56-56 and 57. 
As in the first embodiment, it is contemplated that the secondary valves 60 
should be thinner and more flexible than the primary reed structure 58. 
FIG. 10 is a semi-schematic view of the flow pattern in the second 
embodiment, shown in the general manner of FIG. 5 in relation to the first 
embodiment. Here also, it will be observed that the fluctuation in 
cross-sectional flow area and direction is minimized, thereby reducing 
aerodynamic drag. 
FIGS. 11 to 13 
In considering the embodiment of FIGS. 11 to 13, it is first pointed out 
that the reed cage and reed valves which appear in FIGS. 12 and 13 are of 
exactly the same construction as the reed cage shown in FIGS. 6 to 10, and 
some of the reference numerals applied to the reed cage in FIGS. 6 to 10 
have also been applied to FIGS. 12 and 13. 
It should also be noted that in the embodiment of FIGS. 11-13, the primary 
intake port in the cylinder wall is again indicated at 20, and the 
extended intake porting is again indicated at 20a. 
However, in the embodiment of FIGS. 11, 12 and 13, some additional intake 
flow passages are illustrated. Thus, the engine housing structure 63 
outside of the cylinder liner 14 and in the region outboard of each end of 
the reed cage (the reed cage being generally indicated in FIG. 12 at 64) 
is provided with cavities 65 and 66 with curvilinear surfaces forming flow 
channels having axes generally paralleling the converging surfaces of the 
reed cage, these cavities being readily discerned in FIG. 11 in which the 
reed cage does not appear. The two flow channels 65 and 66 formed in the 
engine housing structure beyond each end of the reed cage are 
interconnected with each other in the region 67; and this junction of the 
passages 65 and 66 is connected with the intake port 20 and, thus, also to 
the extended intake porting 20a and with other passages mentioned below. 
In FIGS. 11 and 12, it will also be seen that one of the primary transfer 
passages 23 is shown, this passage having a port 24 into the cylinder 
above the piston in bottom dead center position, and an inlet port 25 in 
the engine housing structure below the piston, the port 25 being 
positioned below the piston even in bottom dead center position. This type 
of primary transfer passage is preferably employed at both sides of the 
cylinder and is referred to above in connection with the embodiments of 
FIGS. 1-5 and 6-10. 
Although it does not appear in FIGS. 11 to 13, it is contemplated that this 
embodiment also be provided with an auxiliary transfer passage, such as 
shown at 27 in FIGS. 2 and 7. 
The embodiment shown in FIGS. 11 and 12 also includes the passage referred 
to as a supplemental passage, this supplemental passage being identified 
by the reference numeral 23a in FIGS. 11 and 12, the reference numeral 
here being applied toward the end of the supplemental passage adjacent to 
the primary transfer passage 23. As in the embodiments of FIGS. 1-5 and 
6-10, this supplemental passage has communication with the intake chamber 
at the side toward the reed valve cage, the supplemental passage being 
extended from that area for communication with the space below the piston 
in the region of the lower end of the primary transfer passage 23. This 
supplemental passage may communicate with either the primary transfer 
passage 23 itself or with the crankcase spaced in the region of the inlet 
port 25 provided at the lower end of the primary transfer passage 23. 
From FIGS. 11 and 12, it will be seen that the upper and outer end of the 
supplemental passage communicates with the intake chamber in the region 
indicated at 67, thereby providing for intercommunication between the 
supplemental passage 23a, the flow channels 65 and 66 and the intake 
region of the primary intake port 20 and the extended intake porting 20a. 
From examination of FIGS. 11, 12 and 13, it will be seen that the engine 
housing structure has a triangular wall or surface 68 lying adjacent to 
the adjoining triangular end wall of the reed cage, this wall or surface 
68 being congruent with the adjoining end wall 52 of the reed cage. In 
this way, the passages 65 and 66 in the engine housing structure at each 
end of the reed cage provide curvilinear flow channels for receiving fuel 
from both the primary and the secondary valve ports in regions at the ends 
of the reed cage, such flow being indicated by flow arrows applied to FIG. 
12. From the flow arrows, it will be seen that the flow not only extends 
downstream to the intake port in the region 67, but further that the flow 
extends laterally under the side edges of the valve reeds and into the 
cavities 65 and 66 and also into the supplemental passage 23a. 
The use of the supplemental passages 23a in combination with the cavities 
65 and 66 is of particular advantage and importance in the configurations 
of the reed cages disclosed in this application because the interior 
surfaces of the end walls of the reed cage are curved and provide 
effective flow not only in the downstream direction over the reed cage 
apex, but also laterally over the end edges of the inclined walls of the 
reed cage. In effect, in all embodiments herein disclosed, the interior 
curved surfaces of the flow channels in the reed cage include curvilinear 
laterally bevelled edges adjacent to the side edges of the valve ports in 
order to minimize flow velocity fluctuations in the lateral flow from the 
valve port under the side edges of the valve reeds and, thus, into the 
adjoining intake cavities formed in the engine housing structure. This is 
also of importance in minimizing turbulence. This type of laterally curved 
or bevelled edges along the side edges of the ports within the reed cage 
just inside of the valve reeds is desirable in all of the embodiments 
herein disclosed but is of particular significance in the embodiment of 
FIGS. 11-13 (and also in the embodiment of FIGS. 14, 15 and 16, described 
herebelow), in which the lateral flow under the side edges of the valve 
reeds delivers fuel/air not only to the principal intake port area, but 
also to the cavities 65 and 66 and still further to the inlet end of the 
supplemental passage 23a, as particularly shown in FIG. 12. 
The passages 65 and 66 described above may be cast or otherwise formed in 
the engine housing structure as a whole, or may be provided in inserts 
adapted to be assembled with the reed cage being inserted into the cavity 
provided to receive the reed cage. 
The additional curvilinear flow channels 65 and 66 may be employed in any 
of the embodiments disclosed in this application, and these channels 
provide significant improvement in relation to efficient engine operation. 
Fluctuation in flow velocity is diminished, with consequent avoidance of 
unnecessary kinetic energy loss. Turbulence and aerodynamic drag at the 
corners of the reed cage apex are also greatly diminished. 
FIGS. 14 to 16 
FIGS. 14 to 16 illustrate the use of certain features of the present 
invention in still another embodiment of two-cycle engines. In this 
embodiment, as in the embodiment of FIGS. 11 to 13, the arrangement of the 
reed cage conforms with the reed cage shown in FIG. 6 and also as 
described in connection with the embodiment of FIGS. 6 to 10, but the reed 
cage is used in a different position in the engine housing structure, as 
compared with the embodiment of FIGS. 6 to 10. In FIGS. 14 to 16, the 
engine housing structure is provided with an intake passage 69 below the 
lower end of the cylinder, which is indicated generally at 70. The intake 
passage 69 is actually formed in the crankcase casting 71, the cylinder 
casting being connected with the crankcase above the position of the 
intake passage 69. The cylinder includes a liner 72, and in this instance, 
is also provided with a water cooling jacket 73. Main transfer passages 74 
and 75 are also provided, each of these passages having a separate 
delivery port, as indicated at 76 and 77, but at each side of the 
cylinder, the two transfer passages 74 and 75 are provided with a common 
entrance port 78 which may be formed, in part, in the crankcase casting 
71. 
In FIGS. 14, 15 and 16, it will be seen that the reed cage structure 
includes the various components as fully described above with particular 
reference to FIGS. 6, 7 and 8, and also with reference to FIGS. 11, 12 and 
13. 
It will further be seen, especially from FIGS. 16 and 17, that the entrance 
port in which the reed cage is positioned is located so that the reed cage 
apex is directed downstream of the intake passage at a level in the region 
of the inlet ports of the transfer passages. 
In this fourth embodiment, an auxiliary transfer passage 79 is also 
provided, the lower end being in communication with the intake passage 69, 
and the upper end having a port into the cylinder, such as indicated at 28 
in FIGS. 2 and 7. The embodiment of FIGS. 14 to 16, however, is not 
provided with a supplemental passage, such as indicated at 23a in FIGS. 11 
and 12, but desirably includes the curved converging passages 65 and 66, 
which are particularly shown in FIG. 15, these passages being arranged 
beyond the end walls of the reed cage in the same general manner as fully 
explained above with reference to FIGS. 11 and 12. 
Particular attention is directed to FIG. 16 in which flow arrows clearly 
indicate the fuel/air lines of flow. Thus, the flow arrows show the flow 
from both the primary and secondary ports of the reed valve cage in 
substantially direct or straight line flow to and into the intake chamber 
immediately adjoining various of the transfer passages, including both the 
principal transfer passages 74 and 75, and also the auxiliary transfer 
passage 79. From FIG. 16, it will be seen that these flow arrows not only 
extend from the region of the reed cage apex, but also laterally at the 
ends of the reed cage in the region of the curvilinear laterally bevelled 
edges adjacent the ends of the reed cage and thus into the converging 
passages 65 and 66. This is particularly effective for delivery of 
fuel/air from the end regions of the reed cage into the central intake 
chamber communicating with the various transfer passages. 
The embodiment of FIGS. 14, 15 and 16 thus provides highly effective fuel 
entrance both from the standpoint of avoiding energy loss by reducing 
variations in velocity and also from the standpoint of minimizing 
turbulence. 
FIG. 17 
Curve A of FIG. 17 shows a computer-operated dynamometer test of an engine 
equipped with a valve arrangement as shown in FIGS. 6 to 10, and curve B 
shows a corresponding test of the same engine, but equipped with standard 
reed valve mechanism having a V-shaped reed cage without the aeroform 
surfaces provided by the present invention. 
In FIG. 17, the comparative curves represent the power output of the 
engines with the throttle wide open, and it will be noted from those 
curves that with the throttle wide open, the maximum increase in power 
when using the system of the present invention (Curve A) occurs near the 
top engine RPM. Other similar comparative tests show that at low throttle 
settings the maximum increase in power when using the system of the 
present invention occurs toward the low end of the engine RPM range. These 
operating characteristics are particularly advantageous in a motorcycle 
engine, because the arrangement of the invention provides desirable 
increase in power not only at times of high speed travel of the motorcycle 
when the engine is running at high RPM, but also at starting times when it 
is advantageous to rapidly accelerate the motorcycle with low throttle 
settings.