JP3187650B2 - Two-stroke cycle engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an internal combustion engine (engine).
Specifically, the present invention relates to an improved two-stroke engine that allows for efficient scavenging of combustion gases and high pressure injection of a fuel / air mixture prior to ignition.

[0002]

In a two-stroke cycle engine, scavenging of the combustion gases has been a long-standing unsolved problem and is a major factor in combustion efficiency. However, two-stroke cycle engines have always been found to be unsatisfactory in this regard. Another well-known problem in two-stroke cycle engines is that the pressure differential created during the intake stroke of the piston is
That is, it is not enough to achieve efficient atomization of the fuel / air mixture. Various pumps and electronic fuel injectors have been proposed to reduce pumping losses for efficient atomization. However, pumps and electronic fuel injectors are very costly.

[0003] Thus, there is a need for an improved two-stroke cycle engine to overcome the above disadvantages.
It remained unresolved for a long time.

[0004]

In accordance with one aspect of the present invention, a two-stroke cycle engine includes a cylinder housing having a peripheral wall and ends (first and second ends), and reciprocable within the cylinder housing. And a piston assembly dividing the cylinder housing into a combustion chamber at a first end and an air chamber at a second end, and means for converting reciprocating motion of the piston assembly into rotational motion.

[0005] The first wall of the cylinder housing is
An exhaust port is formed adjacent to the end. In addition, an intake port is formed in the peripheral wall of the cylinder housing adjacent to the second end. The engine further includes a scavenging conduit having first and second ends on a peripheral wall of the cylinder housing, wherein the distance between the first end of the scavenging conduit and the first end of the cylinder housing is equal to the distance of the cylinder housing. Is larger than the distance between the exhaust port and the first end.

The engine further has a fuel / air intake conduit having a first end on a peripheral wall of the cylinder housing and a second end on a second end of the cylinder housing. The distance between the first end and the first end of the cylinder housing is greater than the distance between the first end of the scavenging conduit and the first end of the cylinder housing.

[0007] The fuel / air intake conduit includes a venturi portion adjacent a first end thereof. Fuel injection means are provided for the purpose of fuel injection, comprising a nozzle mounted on the venturi section and a jet mounted between the venturi section and the fuel / air intake conduit.

[0008] Preferably, the first end of the scavenging conduit and the fuel /
The first and second ends of the air intake conduit may each include a check valve and the inlet may include a reed valve to prevent unwanted backflow of fluid.

An accumulator is provided between the venturi section and the second end of the fuel / air intake conduit to ensure high pressure injection of the fuel / air mixture.

The piston assembly has a compression stroke and a power stroke, including an exhaust stroke, a scavenging stroke, and a fuel / air injection stroke, in the cylinder housing, wherein the scavenging conduit and the first end of the fuel / air intake conduit. Is closed during the exhaust stroke, the first end of the fuel / air intake conduit is closed during the scavenging stroke, and the second end of the scavenging conduit is closed during the fuel / air injection.

Preferably, the exhaust vent begins to open when the piston assembly is at a crank position about 100 ° after top dead center. Piston assembly about 110 ° after ATDC
At the crank position, the first end of the scavenging conduit begins to open, thus beginning the scavenging stroke. Second of scavenging conduit
The end is completely closed, thus ending the scavenging stroke, with the piston assembly in the crank position approximately 130 ° after top dead center.

The first end of the fuel / air intake conduit begins to open when the piston assembly is at the crank position of about 140 ° ATDC, thus initiating the fuel / air injection stroke. Fuel is injected from the nozzle into the venturi section,
It is then carried by high pressure air to a jet where it is injected into the combustion chamber.

[0013] Preferably, a solenoid valve is provided between the accumulator and the venturi portion, and a sensor is provided between the throttle and the solenoid valve. The sensor is
A signal is sent to control the opening and closing of the solenoid valve in response to a change in the angular position of the throttle.

According to another aspect of the present invention, a cylinder housing includes a first portion and a second portion having an inner diameter that is greater than the inner diameter of the first portion. A piston assembly is reciprocally received in the first and second portions of the cylinder housing, respectively, and has a relatively small first end defining a combustion chamber and an air chamber, respectively, in the first and second portions of the cylinder housing. And a relatively large second end.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. 1 and 2, a reciprocating two-stroke cycle engine according to the present invention includes a cylinder housing 10 in which a piston assembly is received. The piston assembly comprises a double head piston 12, and the piston has a block 14 extending inward from the inner surface of each of the two piston heads 16a and 16b, defining a space between the two blocks 14. ing. The piston 12
A first and second portion of the cylinder housing defines a combustion chamber and an air chamber, respectively. In this embodiment, the skirt portion 16c is
a, which extends toward the right piston head 16b, and which extends leftward from its periphery to form a flange 16 forming a recess.
d, and four rods 13 are provided to connect the left and right piston heads 16a and 16b to form an integral unit. A crankshaft 20 is supported on the central peripheral wall of the cylinder housing 10 by two bosses 21 (only one of which is shown), but the crankshaft 20 moves through the cylinder housing 10 through piston heads 16a and 16b.
Penetrating transversely between the crank portions 22
have. This crank portion has a diameter substantially equal to the distance between the two blocks 14 and fits in the space between the two blocks 14. Each block 14
The transverse length of the crank part 22 always contacts the two blocks, i.e. during operation, the crank part 22
Is long enough to ensure that it is guided in the space between the two blocks. Each piston head 16a and 16
For b, two piston rings (not numbered) are provided for lubrication and sealing purposes. A spark plug 30 is provided at a first end of the cylinder housing. U.S. Patent No. issued to Hayashi on December 4, 1984
It will be appreciated that other devices, such as the mechanism shown in U.S. Pat. No. 4,486,157, may be applied to the present invention.

Referring to FIGS. 1 and 2 and further to FIG. 4, an exhaust port 32 is formed in the peripheral wall of the cylinder housing 10 and adjacent to a first end thereof. Further, an intake port 34 is formed on the peripheral wall of the cylinder housing 10 and adjacent to the second end thereof. The engine also
It has a scavenging conduit 40, which has a first end formed on the peripheral wall of the cylinder housing 10 and adjacent to its first end, and a second end on the peripheral wall of the cylinder housing 10 and its second end. A second end is formed adjacent to the end. Thus, the distance between the first end of the scavenging conduit 40 and the first end of the cylinder housing 10 is greater than the distance between the exhaust port 32 and the cylinder housing 10.

The engine further comprises a fuel / air intake conduit 5
0, but this conduit has a first end provided on the peripheral wall of the cylinder housing 10 and adjacent to its first end, and a second end provided on the second end of the cylinder housing 10. And an end. Thus, the distance between the first end of the fuel / air intake conduit 50 and the first end of the cylinder housing 10 is between the first end of the scavenging conduit 40 and the first end of the cylinder housing 10. Is greater than the distance of

Preferably, the fuel / air intake conduit 50 comprises
A venturi portion 52 may be provided adjacent the first end. Injection means are provided for the purpose of fuel injection, which are provided by the nozzle 54 of the venturi section 52.
And a jet 56 between the venturi section 52 and the first end of the fuel / air conduit 50.

Preferably, a check valve 3 is provided for the first end of the scavenging conduit 40 and each of the first and second ends of the fuel / air intake conduit 50 to prevent unwanted backflow of fluid.
6 are provided, and a reed valve 38 is preferably provided for the intake port 36. Further, to ensure sufficient high pressure injection of the fuel / air mixture,
An accumulator 58 is provided between the venturi section 52 and the second end of the conduit 50.

Fuel is supplied from a fuel tank 60 and then passes through a filter 62 and a fuel lever controller 64 before entering the nozzle 54. As usual, fuel /
A throttle 51 may be provided in the fuel / air intake conduit 50 between the second end of the tube and the accumulator 58 to control the intake of the air mixture.

[0021] Preferably, a solenoid valve 90 or other control valve is provided between the accumulator 58 and the venturi section 52 of the fuel / air intake conduit 50. A sensor 92 is provided between the throttle 51 and the solenoid valve 90.
Is arranged. The sensor 92 detects the angular position of the throttle 51 and sends a signal to the solenoid valve 90 to control the opening and closing of the throttle 51. The solenoid valve 90 opens during each rightward stroke of the piston during high-speed operation, and the piston operates during low-speed operation. Once every two or three right strokes to ensure smooth operation during low speeds and save fuel. In other words, the piston 12 reciprocates within the cylinder due to the inertia of the flywheel (not shown) when the solenoid 90 is closed and does not release compressed air.

For lubrication, an oil pan 70 is provided below an oil outlet 71 in a lower central area of the cylinder housing 10 to receive lubricating oil from an oil inlet 73 in an upper central area of the cylinder housing 10. . A conduit 76 is provided to connect the oil pan 70 and the oil inlet 73. Further, an oil pump, a filter 74 and a bypass pipe 78 may be provided in the lubrication conduit 76. The operation of such a lubrication system of the circulation type is well known and will not be discussed further. FIG. 1 shows an alternative embodiment of the lubrication system in which an internal oil passage 80 is formed along the crankshaft 20. An oil inlet 82 is formed outside the cylinder housing 10, while an outlet 84 is outside the cylinder housing 10, preferably the crankshaft 20.
It is good to be formed in the central part of. Such pressure type lubrication systems are also well known and therefore will not be discussed further. It will be appreciated that other lubrication systems may be utilized in the present invention without departing from the spirit of the invention.

[0023]

FIG. 3 to FIG. 4 to FIG. FIG.
Shows the state in which the power stroke is about to start, while the exhaust port 32 is blocked by the skirt portion 16c. In FIG. 5, the vent 32 has begun to open, at which time the piston assembly is moved from about 95 ° to 105 ° (preferably 100 °) after top dead center (ATDC) of the piston.
°) crank position, thus starting the exhaust stroke.

In FIG. 6, the first end of the scavenging conduit 40 begins to open, at which time the piston assembly moves about 110
° At ATDC crank position, thus starting scavenging stroke. In FIG. 7, the first end of the scavenging conduit 40 is completely open and the piston assembly is in the crank position at 120 ° ATDC. In FIG. 8, the second end of the scavenging conduit 40 is completely closed, thus terminating the scavenging stroke, when the piston assembly is now about 130 °.
ATDC crank position.

Referring to FIG. 9, a fuel / air intake conduit 50 is shown.
Begins to open, at which time the piston assembly is at a crank position of about 140 ° ATDC, thus beginning the fuel / air injection stroke. In FIG. 10, the fuel /
The first end of the air intake conduit 50 is completely open,
The piston assembly is then at a crank position of about 150 ° ATDC. Fuel is injected from nozzle 54 into venturi section 52 and is delivered to jet 56 (by high pressure from accumulator 58 in response to the fuel / air injection stroke of the piston assembly), where the fuel / air mixture is removed from the combustion chamber. Injected inside. As described above, the solenoid 90 valve operates in response to the angular position of the throttle 51. In FIG. 11, the engine is in its initial use in its compression stroke, compressing the fuel / air mixture in the combustion chamber for subsequent ignition.

[0026]

Second Embodiment FIG. 12 shows another embodiment of the present invention, in which a cylinder housing 10 has a first portion 10a and a larger diameter than the first portion 10a. A second part 10b and a piston 12
Has a relatively small end 16a and a relatively large end 16b reciprocally received in first and second portions of the cylinder housing 10, respectively. Second
The remaining structure and operation of this embodiment is the same as the first embodiment described above, and therefore will not be described further.

[0027]

In accordance with the foregoing description, the present invention provides a novel two-stroke cycle engine that utilizes air in an air chamber to scavenge and effectively introduce a fuel / air mixture into a combustion chamber. Will be recognized. Such a structure can provide higher thermal efficiency than conventional ones.

While the invention has been illustrated and described with reference to a preferred embodiment, it will be appreciated by those skilled in the art that many other variations and modifications can be made without departing from the spirit of the invention.

[Brief description of the drawings]

FIG. 1 is a perspective view of a two-stroke cycle engine according to the present invention, with the scavenging conduit, fuel / air intake conduit and lubrication conduit removed for clarity.

FIG. 2 is an exploded view of the two-stroke cycle engine of FIG.

FIG. 3 is a diagram showing a preferred timing relationship for a two-stroke cycle engine according to the present invention.

FIG. 4 is a cross-sectional view of a two-stroke cycle engine according to the present invention, showing a state where the engine is about to start its power stroke.

FIG. 5 is a cross-sectional view of a two-stroke cycle engine according to the present invention, showing a state in which the engine is about to exhaust combustion gases.

FIG. 6 is a cross-sectional view of a two-stroke cycle engine according to the present invention, showing that the left end of the scavenging conduit of the engine is about to open to scavenge combustion gases.

FIG. 7 is a cross-sectional view of a two-stroke cycle engine according to the present invention, showing a state in which a left end of a scavenging conduit is completely opened.

FIG. 8 is a cross-sectional view of a two-stroke cycle engine according to the present invention, showing a state in which a right end of a scavenging conduit is completely closed.

FIG. 9 is a cross-sectional view of a two-stroke cycle engine according to the present invention, showing a state where the left end of the fuel / air intake conduit of the engine is about to open.

FIG. 10 is a cross-sectional view of a two-stroke cycle engine according to the present invention, showing the engine with just the left end of the fuel / air intake conduit fully open.

FIG. 11 is a sectional view of a two-stroke cycle engine according to the present invention, showing a state where the engine is about to start a compression stroke.

FIG. 12 is a schematic diagram showing another embodiment of a two-stroke cycle engine according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Cylinder housing 12 Double head piston 13 Rod 14 Block 16a, 16b Piston head 16c Skirt part 16d Flange 20 Crankshaft 21 Boss 22 Crank part 30 Spark plug 32 Exhaust port 34 Inlet port 36 Check valve 40 Scavenging pipe 50 Fuel / air intake Conduit 51 Restrictor 52 Venturi portion 54 Nozzle 56 Jet 58 Accumulator 60 Fuel tank 62 Filter 64 Fuel lever controller 72 Oil pump 74 Filter 76 Lubrication conduit 78 Bypass tube 90 Solenoid valve 92 Sensor

Claims (11)

(57) [Claims] A cylinder housing having a peripheral wall and first and second ends; reciprocally received within the cylinder housing;
A piston assembly dividing the cylinder housing into a combustion chamber at a first end thereof and an air chamber at a second end thereof; means for converting reciprocating motion of the piston assembly into rotary motion; An exhaust port formed on the peripheral wall of the end portion and adjacent to the first end portion; an intake port formed on the peripheral wall of the cylinder housing and adjacent to the second end portion; A scavenging conduit having first and second ends, wherein the distance between the first end of the scavenging conduit and the first end of the cylinder housing is the distance between the exhaust port of the cylinder housing and the first end. A fuel / air conduit having a scavenging conduit set larger than the first end and a first end at a peripheral wall of the cylinder housing and a second end at a second end of the cylinder housing. The distance between the first end portion of the first end portion and the cylinder housing of the air intake conduit, the scavenging conduit 1
A fuel / air intake conduit set greater than a distance between the end and a first end of the cylinder housing, wherein the piston assembly has a compression stroke, an exhaust stroke, a scavenging stroke and a fuel stroke within the cylinder housing. A power stroke including an air / air injection stroke, wherein the scavenging conduit and the first end of the fuel / air intake conduit are closed during the exhaust stroke, the first end of the fuel / air intake conduit is closed during the scavenging stroke, fuel/
A two-stroke cycle engine wherein the second end of the scavenging conduit is closed during the air injection stroke. 2. A first part having a peripheral wall and an end wall, a cylinder housing having a peripheral wall and an end wall and having an inner diameter larger than an inner diameter of the first part, and first and second cylinder housings. Pistons having a relatively small first end and a relatively large end reciprocally received in respective portions and defining a combustion chamber and an air chamber in the first and second portions of the cylinder housing, respectively. An assembly; means for converting a reciprocating portion of the piston assembly into rotary motion; an exhaust port formed in a peripheral wall of a first portion of the cylinder housing; and an intake port formed in a peripheral wall of a second portion of the cylinder housing. A mouth and a first end on the peripheral wall of the first part of the cylinder housing;
A scavenging conduit having a second end on a peripheral wall of a second portion of the cylinder housing, wherein a distance between the first end of the scavenging conduit and an end wall of the first portion of the cylinder housing is an exhaust port of the cylinder housing. A scavenging conduit set to be greater than the distance between the first end portion and the end wall of the first portion;
A fuel / air intake conduit having a second end at an end wall of a second portion of the cylinder housing, between the first end of the fuel / air intake conduit and an end wall of the first end of the cylinder housing. A fuel / air intake conduit having a distance greater than a distance between a first end of the scavenging conduit and an end wall of the first end of the cylinder housing, wherein the piston assembly includes: A compression stroke and a power stroke including an exhaust stroke, a scavenging stroke and a fuel / air injection stroke, wherein the scavenging conduit and a first end of the fuel / air intake conduit are closed during the exhaust stroke, and the fuel / air during the scavenging stroke. The first end of the intake conduit is closed and the fuel /
A two-stroke cycle engine wherein the second end of the scavenging conduit is closed during the air injection stroke. 3. The method according to claim 1, wherein the piston assembly is about 95 ° after top dead center.
3. The two-stroke cycle engine according to claim 1, wherein the exhaust port starts opening when the crank position is at 105 °. 4. The piston assembly is at about 110 ° after top dead center.
A two-stroke cycle engine according to claim 1 or 2, wherein the first end of the scavenging conduit begins to open when in the crank position. 5. The piston assembly is approximately 130 ° after top dead center.
3. The two-stroke cycle engine according to claim 1, wherein the second end of the scavenging conduit is closed when in the crank position. 6. The piston assembly is at about 140 ° after top dead center.
In the first crank position of the fuel / air intake conduit
A two-stroke cycle engine according to claim 1 or 2, wherein the ends begin to open. 7. The two-stroke cycle engine of claim 1, wherein the fuel / air intake conduit includes a venturi portion adjacent a first end thereof. 8. The two-stroke cycle according to claim 7, comprising injection means including a nozzle mounted on the Venturi portion and a jet mounted between the Venturi portion and the first end of the fuel / air intake conduit. engine. 9. The two-stroke of claim 8, wherein each of the first end of the scavenging conduit and the first and second ends of the fuel / air intake conduit comprise a check valve and the intake comprises a reed valve. Cycle engine. 10. The two-stroke cycle engine according to claim 9, wherein the fuel / air intake conduit comprises an accumulator provided between the venturi portion and the second end of the fuel / air intake conduit. 11. A solenoid valve provided between an accumulator and a venturi portion, and a sensor connected between the throttle and the solenoid valve, wherein the sensor is responsive to a change in the angular position of the throttle. Send a signal to the solenoid valve,
The two-stroke cycle engine according to claim 10, wherein opening and closing of the solenoid valve is controlled.