Note: Descriptions are shown in the official language in which they were submitted.
CA 02580587 2007-05-09
Engine
Background of the Invention
1. Field of the Invention
The invention is related to the structure of two-stroke internal combustion
engine. Especially, it involves a type of engine that converts the instant
power of
fuel into cyclic linear movement of external piston.
2. Description of the Prior Art
Current internal combustion engine (engine) is mainly two-stroke or
four-stroke. Please refer to Figure 1 for the structure for a common two-
stroke
engine. Its cylinder block 10 has an air intake 11 and an air exhaust 12 on
two
opposite sides. A piston 13 has a sealing piston ring 14 inside the cylinder
block
10. One end of a connecting rod 15 connects to a piston pin 16 inside the
piston 13.
The other end of the connecting rod 15 connects to a crankshaft 18 inside a
crankcase 17 at the bottom of a cylinder block 10. When the piston 13 is in an
upward stroke at the top of cylinder block 10 to compress the mixed fuels, a
spark
plug 19 ignites the fuels to explode and force the piston 13 in a downward
stroke.
Then through the crankshaft 18, the power is output. When the piston 13 is
below
the air exhaust 12 in a downward stroke, the combustion waste gases are
exhausted. Upon exhausting the waste gases, the air exhaust 12 experiences
Venturi effect that builds up pressure in the crankcase, so the pressure in
the top of
the cylinder block 10 becomes negative. The air intake 11(with check valve)
sucks
in mixed fuel gases. At this moment, the piston 13 uses the rotational power
from
the connecting rod 15 and the crankshaft 18 to generate an upward stroke and
compress the mixed fuel gases again and ignite to explode. From the
description
above, it is known that two-stroke engine has advantages in simple structure,
low
power loss and high power output. Since the piston 13 passes by the air intake
11
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and the air exhaust 12 on two opposite sides of the cylinder block 10 in an
upward
stroke and a downward stroke, the crankcase 17 cannot store engine oils
inside. But
because mechanical movenient needs lubrication, the two-stroke engine needs
lubricants in its fiiels. Thus, combustion causes lubricant film formation and
is
apparently incomplete. This leads to emission of polluting waste gases that
cause
environnlental issues. The objective of the invention is for two-stroke engine
to
minimize pollution from emission of waste gases and increase its power output.
Summary of the Invention
The invention as claimed is directed to an engine comprising a cylinder block
with a cylinder bore, a main piston and an external piston, said main and
external
pistons together forming a coupled piston;
wherein said external piston is sleeved outside of the main piston and uses
two
side rods to connect to heai-t-shape grooves on two sides of a crankshaft at
the bottom
of the cylinder block and moves with the main piston in an upward stroke and a
downward stroke, and
wherein the two sides of the crankshaft that drives the external piston in an
upward stroke and a downward stroke, consist of a large circular groove and a
small
circular groove.
Therefore, the main objective of the invention is to provide a two-stroke
engine
that places an external piston on the main piston. The external piston uses
two side
connecting rods to connect to the two sides of the crankshaft in a heart-shape
groove
and is able to move witli the main piston in an upward stroke and a downward
stroke,
so the explosive power fi-om combustion is convet-ted to cyclic linear
niotion. This is
to replace complicated air valve structure in a four-stroke engine. The
invention also
adds blocking rings to the skii-t section of the external piston and the main
piston.
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This design and the pre-compression single-streain aii-way inside the
crankcase can
provide lubrication as four-stroke engine does and remove the restriction that
two-stroke engine has to add lubricants to its fuels.
Another objective for the invention is for the external piston to close the
air
intake valve and the air exliaust valve early and block the leaking of the
mixed fuel
gases in the cylinder by angular variation of the heart-shape grooves on the
two
opposite sides of the crankshaft, and also to increase gas intake capacity for
the
cylinder and the compression ratio to add power.
Another objective for the invention is to provide an engine with an oil supply
system that uses the oil pump driven by the heart-shape grooves on the two
sides
of the crankshaft to lubricate mechanical parts and replace carburetors. It
pumps
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out fixed amount of oils in standard mixing ratio and prevents backflow of
oils by
a check valve. Through one-way pressure-regulating valve, the fuel enters in
one
way. Fuel supply is adjustable and a stable amount of fuel is directly
injected to
the cylinder to overcome the shortcoming of traditional carburetors and
electronic
fuel injectors.
Another objective of the invention is to provide an engine that the 1st stage
cylinder bore of the external piston and cylinder block has waving edges, so
when
the external piston and the cylinder block contact each other, there is waving
contact surface and the main piston and the external piston move at the same
time.
The piston ring of the main piston can enter or leave smoothly the chamber of
the
external piston without jamming up the groove.
To realize the above objective, the invention provides an engine that its
cylinder block has coupled piston comprising a main piston and an external
piston.
The mentioned external piston encloses the main piston and uses two sides
connecting rods to connect to the two sides of the crankshaft in a heart-shape
groove inside the crankcase at the bottom of the cylinder block, so it moves
along
with the main piston in an upward stroke and a downward stroke.
It is preferred that the skirt section for the main piston or the external
piston
for the coupled piston has blocking rings to prevent lubricants from leaking
through air intake and air exhaust.
It is more preferred that the heart-shape grooves at the two sides of the
crankshaft driving the external piston in an upward stroke and a downward
stroke
are formed by connection of large and small circular grooves.
It is also more preferred that the heart-shape grooves at the two sides of the
crankshaft are concave, convex or combination of both as toothed wheels.
It is also more preferred that the cylinder bore is two sections in the
cylinder
block, and has two different inner diameters.
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It is also more preferred that that the crankcase at the bottom of the
cylinder
block passes to a single-stream independent airway and controls the direction
of
gas flow through the airway.
It is also more preferred that the gases inside the crankcase at the bottom of
the cylinder block enter the cylinder through a single-stream independent
airway
or leave the crankcase before re-entering the cylinder.
It is also more preferred that the cylinder has a direct fuel injection system
composed of an oil pump, a check valve and a regulating valve. The power for
oil
supply system is generated by the rotation of heart-shape grooves on two sides
of
the crankshaft inside the crankcase at the bottom of the cylinder block.
It is also more preferred that the contact surface of the external piston and
the
first section of the cylinder are waving.
Brief Description of the Drawings
Figure 1 is an illustration for the structure of a common two-stroke engine.
Figure 2 is an illustration for the structure of the engine in the invention
(compression and ignition).
Figure 3 is an illustration for the structure of the engine in the invention
(explosion, main piston in a downward stroke).
Figure 4 is an illustration for the structure of the engine in the invention
(exhaust
and intake).
Figure 5 is an illustration for the structure of the engine in the invention
(external
piston is closing air intake and air exhaust while the main piston is in an
upward
stroke before compression).
Figure 6 is a side view for the connection of the coupled piston and the
crankshaft
in the invention.
Figure 7 is a front view for the connection of the coupled piston and the
crankshaft
in the invention.
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Figure 8 is a cross-section diagram for the coupled piston in the invention.
Figure 9 is an illustration for gas flow in the different sections of the
single-way
independent airway for the invention.
Figure 10 is an illustration for gas flow in the different sections of the
single-way
independent airway for the invention.
Figure 11 is an illustration for the direct fuel injection system for the
cylinder in
the invention.
Figure 12 is an illustration for the oil pump system of the lubrication device
in the
invention.
Figure 13 is an illustration for the structure of the joint between the
external piston
and the cylinder block in the invention.
Figure 14 is an illustration for the operation of the joint in Figure 13 and
the piston
ring of the main piston.
Detailed Description of the Preferred Embodiment
To further explain the objective, features and benefits for the invention, a
preferred embodiment is described as follows:
Please refer to figures from Figure 2 to Figure 8. The structure for the
engine
in the invention mainly uses a coupled piston structure consisting of a main
piston
and an external piston 30 inside a cylinder block 10. When the coupled piston
20 moves inside the cylinder block 10 in an upward stroke and a downward
stroke,
the external piston 30 can open or close the air intake 11 and the air exhaust
12 on
the two opposite sides of the cylinder block 10. This prevents the lubricants
171
stored inside the crankcase 17 from leaking out. Thus, the invention utilizes
the
lubrication concept of four-stroke engine to over come the restriction that a
two-stroke engine has to add lubricants in the fuels to improve the emission
of
waste gases. The features for the invention are as in Figure 8 that shows the
main
piston 20 has a sealing piston ring 21 at top and a sealing blocking ring 22
at skirt;
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the external piston 30 has a chamber 31 passing through its interior, a
sealing
piston ring 32 at top, a sealing blocking ring 33 at skirt; the main piston 20
is able
to move up and down inside the chamber 31 of the external piston 30; one end
of a
connecting rod 15 connects to a piston pin 16 and also links to the main
piston 20
while the other end connects to the crankshaft 18 inside the crankcase 17 at
the
bottom of the cylinder block 10; a rod seat 34 at the two opposite sides of
the
bottom end of the skirt of the external piston 30 is for connection of one end
of the
rod 35 while the other end connects to a guide pulley 36, so the rod 35 uses
the
guide pulley 36 to lie against to the heart-shape grooves on the two sides of
the
crankshaft 18 and is thus driven to move the external piston 30 in a upward
stroke
and a downward stroke; the heart-shape groove is a ring-shape grooves on the
two
sides of the crankshaft 18, concave or convex or combination of both as
toothed
wheel, with one half as large circular groove 41 coaxial with the crankshaft
18 and
the other half forms two small circular groove 42A and 42B non-coaxial with
the
crankshaft 18; a groove low point 43 is formed and near the center of
crankshaft
18 between openings of the two small circular grooves 42A and 42B; the
interior
of cylinder block 10 has two sections, the 1 st stage cylinder bore l0A
equivalent
to the outside diameter of the main piston 20, the 2nd stage cylinder bore l
OB
equivalent to the outside diameter of the external piston 30, while the air
intake 11
and the air exhaust 12 on the two opposite sides of the cylinder block 10 are
located on the 2nd stage cylinder bore l OB ; as shown in Figure 2, Figure 6
and
Figure 7 at this location the crankshaft 18 uses the connecting rod 15 to push
the
main piston 20 up to inside the 1 st stage cylinder bore 10A of the cylinder
block
10, and the main piston 20 uses its top piston ring 21 to seal the compressed
mixed
fuel gases, and the heart-shape grooves on the two sides of the crankshaft 18
use
the large circular groove 41 to push against the guide pulley 36 of the rod 35
and
allow the external piston 30 to remain at the top of the 2nd stage cylinder
bore
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l OB of the cylinder blockl0, and the piston ring 32 and the blocking ring 33
at the
top and the skirt are around the position of the air intake and the air
exhaust 11, 12
to stop the lubricants inside the crankcase 17 from leaking through the air
intake
and the air exhaust 11, 12; as shown in Figure 3 at this position, the spark
plug 19
ignites the compressed mixed fuel gases and pushes the main piston 20 in a
downward stroke into the chamber 31 of the external piston 30, and the
downward
main piston 20 uses the connecting rod 15 to push the crankshaft 18
counterclockwise 90 degrees, and the rods 35 at the two sides of the external
piston 30 still have their guide pulley 36 inside the heart-shape large
circular
groove 41, so the rods 35 do not move with the main piston 20 and are still at
the
position to seal the air intake and the air exhaust 11, 12; as shown in Figure
4 at
this position the main piston 20 continues its downward stroke and uses the
connecting rod 15 to push the crankshaft 18 counterclockwise to 180 degrees,
and
at the same time the guide pulley 36 on the rods 35 on the two sides of the
external piston 30 enters from one small circular groove 42B into the heart-
shape
groove low point 43, and the rod 35 can pull the external piston 30 and moves
together with the main piston 20 downward to open the air intake and the air
exhaust 11, 12; as shown in Figure 5 at this position the crankshaft 18
continues to
rotate counterclockwise to about 270 degrees and pushes the main piston 20 and
the external piston 30 together upward to the top point of the 2nd stage
cylinder
bore l OB of the cylinder block 10, and the external piston 30 seals the air
intake
and the air exhaust 11, 12 again until it gets back to the position shown in
Figure 2,
and the crankshaft 18 completes a full cycle (360 degrees) and drives the main
piston 20 upward again to compress the mixed fuel gases; in summary, the
coupled piston composed of the main piston 20 and the external piston 30 is to
prevent the leaking of lubricants 171 inside the crankcase 17 from leaking
through
the air intake and the air exhaust 11, 12, and a four-stroke engine concept is
used
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to solve the emission pollution issue for two-stroke engine that had to add
lubricants to the fuels; further, through the angular variation of the large
circular
grooves 41 on the two sides of the crankshaft 18 and the two small circular
grooves 42A, 42B, the external piston 30 can close out in an early time the
air
intake and air exhaust 11, 12 on the two opposite sides of the cylinder block
10 to
prevent the leaking of the mixed fuel gases inside the cylinder block 10, and
the
external piston 30 can also increase air intake to raise up the compression
ratio
and the power output as well.
Please refer to Figure 9 and Figure 10. They are the illustrations for gas
flow
in the different sections of the single-way independent airway for the
invention.
The inlet of the single-flow independent airway 50 has throttle valve 51 and
the
first check valve 52, and the second check valve 53 on the way to the
crankcase 17,
the third check valve 54 on the same way to the airway 50, and the end of the
independent airway 50 connects to the air intake 11 for the cylinder block 10,
and
a fuel injector 55 or a carburetor 56 is in the middle; thus, the independent
airway
50 capacity is determined by the air intake volume due to the upward stroke of
the
main piston 20 and the external piston 30 inside the cylinder block 10 to the
top
point of the crankcase 17, as shown in Figure 9. When the main piston 20 and
the
external piston 30 move upward to the top point (compression, ignition), an
equal
amount of air intake from the crankcase 17 lowers the air pressure inside the
crankcase 17 and opens up the second check valve 53 to allow outside air going
to
the airway 50 (indicated by X); as shown in Figure 10, when the main piston 20
and the external piston 30 move downward to the bottom point (explosion,
exhaust) of the cylinder block 10, they compress the air inside the crankcase
17
and close the first check valve 52 and the second check valve 53, and open the
third check valve 54, and press the mixed lubricated fuel gases (indicated by
0)
inside the crankcase 17 into the independent airway 50 and push the outside
air
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(indicated by X) already inside the independent airway 50 through the fuel
injector 55 or the carburetor 56 and the air intake 11 to the cylinder block
10; in
this way, the invention uses the first check valve 52, the second check valve
53
and the third check valve 54 to control the single-way flow in the airway, and
allow the outside air (indicated by X) and the crankcase 17 fuel gases
(indicated
by 0) to enter in sequence, and as a result the fuel gases (indicated by 0)
inside
the crankcase 17 always circulate in the independent airway 50 and the
crankcase
17, and after the outside air (indicated by X) enters the independent airway
50, it
does not enter the crankcase 17, instead, is pushed through the fuel injector
55 or
the carburetor 56 and the air intakel l to the inside of the cylinder block
10.
Please refer to Figure 11 for the coupled piston and the direct fuel injection
system in the invention. The oil supply system consists of an oil pump 60, a
check
valve 62, one-way regulating valve 63 and the fuel lines 61 in the middle. The
oil
pump 60 is driven by the rotation of the heart-shape grooves on the two sides
of
the crankshaft 18 and the standard mixed fuel is sucked through fuel feed
lines
631 and the one-way regulating valve 63 into the oil pump 60. After
pressurization
of the oil pump 60, the fuel is injected by the check valve 62 and the fuel
injector
55 into the cylinder block 10. The valve body 621 of the check valve 62 is
subject
to push by the rear spring 622 to close the valve port 623 and stop the
backflow of
the fuel inside the fuel injector 55. Please refer to A-A Figure. The four
sides of
the valve body 621 are four flat surfaces. When the oil pump 60 pumps a
certain
quantity of fuel to push the valve body 621 backward to open the valve port
623,
the fuel can pass through the clearance 624 among four flat sides and flow to
the
fuel injector 55 through the check valve 62; the one-way regulating valve 63
has a
regulating screw 636 in the front end, a fuel feed line 631 on its side, a
fuel line 61
connecting to an oil pump 60 in the back, and a valve rod 632 penetrating
inside
the valve body 633. The valve rod 632 and the valve body 633 have four flat
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surfaces on four sides. Pressurized gasoline through the fuel feed line 631
enters
the one-way regulating valve 63 and flows between clearance 634 between flat
surfaces on the four sides of the valve rod 632 to push the valve rod 632
forward
and open, so the fuel flows into the fuel line 61 in one way. When the oil
pump 60
pumps the fuel in the fuel line 61 into the check valve 62, if pressure is
built up, it
can push back the valve body 623 of the one-way regulating valve 63 and the
valve rod 632 backward. This allows the pressurized fuel to flow back to the
inside of the one-way regulating valve 63 through the flat clearance 635 on
the
four sides of the valve body 633, then flow back to the fuel tank through the
fuel
feed line 631. Thus, it enables the fuel injector 55 injects the fuels to the
cylinder
block 10 stably and directly.
Please refer to Figure 12. The invention uses a coupled piston that moves
simultaneously and is added a lubricating oil pump. The oil pump system
includes
an oil pump 70 and its fuel feeding check valve port 71, fuel discharge check
valve port 72. The oil pump 70 is driven by the rotating heart-shape groove on
the
two sides of the crankshaft 18 or the rod 35 of the external piston 30.
Please refer to Figure 13 and Figure 14 for the structure of the joint of the
external piston and the cylinder block and its relation with the piston ring
of the
main piston. The top of the chamber 31 for the external piston 30 has waving
flange 80. The bottom of the 1 st stage cylinder bore 10A for the cylinder
block 10
has corresponding waving flange 81. When the external piston 30 is located at
the
top of the 2"d stage cylinder bore lOB for the cylinder block 10. The waving
flange
80 at the top of the chamber 31 is inserted into the waving flange 81 at the
bottom
of the 1 st stage cylinder bore l 0A. In this way, it forms waving j oint (as
shown in
Figure 14). When the main piston 20 is in the same upward and downward strokes
with the external piston 30 in the chamber 31, when the piston ring 21 passes
the
interface of the external piston 30 and the 1st stage cylinder bore 10A, it
passes
CA 02580587 2007-05-09
smoothly, so the piston ring 21 for the main piston 20 will not be stuck in
the
groove.
In summary, the invention improves the emission for a two-stroke engine
without the complicated structure of valves in a four-stroke engine, and also
increases air intake for the cylinder and its compression ratio to boost the
power
output. Besides, it also has the advantage of using the direct fuel injection
system
without carburetor.
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Description of Main Components
cylinder block 10A 1 st stage cylinder bore 10B 2nd stage cylinder bore
11 air intake 12 air exhaust 13 piston
14 piston ring 15 Connecting rod 16 piston pin
17 crankcase 171 Lubricating oil 18 crankshaft pin
19 spark plug 20 Main piston 21 piston ring
22 blocking ring 30 External piston 31 chamber
32 piston ring 33 Blocking ring 34 rod seat
35 rod 36 guide pulley 41 large circular groove
42A small circular groove 42B small circular groove
43 groove low point 50 One-way independent 51 throttle valve
airway
52 1 st check valve 53 2nd check valve 54 3rd check valve
55 fuel injector nozzle 56 carburetor 60 oil pump
61 fuel line 62 check valve 621 valve body
622 compression spring 623 valve port 624 clearance
63 one-way regulating 631 fuel feeding intake oil 632 valve rod
valve tuning check hose
valve
633 valve body 634 valve rod clearance 635 valve body clearance
636 regulating screw 70 oil pump 71 Fuel feeding check
valve port
72 Fuel discharge check 80 waving convex flange 81 waving concave flange
valve port
82 Waving joint
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