JP3723691B2 - Air cleaner for stratified scavenging engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an air cleaner for a stratified scavenging engine that is attached to a carburetor having a scavenging leading air passage and an air-fuel mixture forming air passage in parallel.
[0002]
[Prior art]
FIG. 9 is a side sectional view of a stratified scavenging two-cycle engine 1a provided with a conventional air cleaner 40d. A spark plug 4 is attached to the top of the cylinder 3 attached to the crankcase 2. A piston 5 is fitted into the cylinder 3 so as to be slidable in the vertical direction. The piston 5 is connected to a crank 6 that is rotatably attached to the crankcase 2 by a connecting rod 7. The cylinder 3 is provided with a scavenging passage 10 and a scavenging port 11, and an air mixture passage 12 and an air mixture port 13 below the scavenging passage 10 and the scavenging port 11. Further, an exhaust passage 14 and an exhaust port 15 are provided to face the scavenging passage 10. The scavenging port 11 communicates with the crankcase 2 through a communication passage 16, and a check valve 17 is provided in the scavenging passage 10. A vaporizer 30 is attached to the upstream side of the scavenging passage 10 and the mixture passage 12 via an insulator 20. The carburetor 30 is provided with a scavenging leading air passage 31 and an air-fuel mixture forming air passage 32 in parallel, and the insulator 20 has a leading air introduction passage 21 connected to the leading air passage 31 of the carburetor 30 and a carburetor. An air-fuel mixture introduction passage 22 connected to the 30 air-fuel mixture formation air passages 32 is provided. A body 41a of an air cleaner 40d is attached to the upstream side of the carburetor 30, and a cylindrical intake passage 42 is formed in the body 41a. A cover 43b is detachably attached to the body 41a so as to cover it, and an air cleaner chamber is formed between the cover 43b and the body 41a.
[0003]
Next, the operation will be described. FIG. 9 shows a case where the piston 5 is at the top dead center. In this state, the air-fuel mixture is compressed in the upper part of the cylinder 3, and the scavenging port 11 and the exhaust port 15 are closed by the lower part of the piston 5. Further, the air-fuel mixture port 13 is in an open state. When the piston 5 is raised, the lower pressure inside the cylinder 3 and the internal pressure of the crankcase 2 are low. Therefore, the pressure of the scavenging passage 10 is lowered through the communication passage 16, and the leading air passage 31 of the carburetor 30 sucks the leading air from the intake passage 42 of the air cleaner 40d. Then, the leading air opens the check valve 17 of the scavenging passage 10 of the cylinder 3 through the leading air introduction passage 21 of the insulator 20 and fills the scavenging passage 10 and the communication passage 16. At the same time, since the pressure of the air-fuel mixture passage 12 also decreases, air is sucked into the air-fuel mixture forming air passage 32 of the carburetor 30 from the air intake passage 42 of the air cleaner 40d. The sucked air is mixed with fuel in the mixture forming air passage 32, and the mixture is filled into the crankcase 2 from the mixture port 13 through the mixture introduction passage 22 of the insulator 20.
[0004]
Next, when the air-fuel mixture compressed at the top of the piston 5 is ignited by the spark plug 4, the air-fuel mixture explodes, and the piston 5 is pushed down by the pressure. When the piston 5 descends, the internal pressure of the crankcase 2 rises, the pressure in the communication passage 16 and the scavenging passage 10 rises, and the check valve 17 is closed. Further, when the piston 5 is lowered and its lower end edge passes the lower edge of the mixture port 13, the piston valve is closed, and the crankcase 2 and the mixture passage 12 are shut off.
When the piston 5 further descends and its top passes the upper edge of the exhaust port 15, the exhaust gas begins to be discharged from the exhaust port 15. At substantially the same time, the top of the piston 5 passes the upper edge of the scavenging port 11, and the leading air whose pressure has increased in the communication passage 16 flows into the cylinder 3 from the scavenging port 11 and discharges the combustion gas from the exhaust port 15. Thereafter, the air-fuel mixture is pumped into the cylinder 3 through the communication path 16 until the piston 5 reaches bottom dead center. As described above, the combustion gas is pushed out by the leading air during the exhaust, and the air-fuel mixture is supplied into the cylinder 3 whose pressure has decreased after the leading air. Therefore, the amount of air-fuel mixture discharged from the exhaust port 15 to the outside is extremely small, and air pollution is prevented.
When the piston 5 passes the bottom dead center, the piston 5 rises and compresses the air-fuel mixture in the cylinder 3, and the internal pressure of the crankcase 2 decreases to repeat the above-described operation.
[0005]
[Problems to be solved by the invention]
However, since the piston valve type is used in the above configuration, the piston 5 is lowered, and the lower end of the piston 5 reaches the lower edge of the mixture port 13 and closes the mixture port 13. Therefore, the air-fuel mixture in the crankcase 2 flows back into the air-fuel mixture passage 12 and passes through the air-fuel mixture introduction passage 22 of the insulator 20 and the air-fuel mixture formation air passage 32 of the carburetor 30 to the air intake passage 42 of the air cleaner 40d. A so-called blow-back phenomenon occurs. As a result, the air-fuel mixture flows into the leading air passage 31 of the carburetor 30 as indicated by an arrow, the amount of air-fuel mixture mixed in the leading air increases, and the air-fuel mixture is discharged together with the combustion gas to pollute the atmosphere. There's a problem.
[0006]
The present invention has been made paying attention to the above-described problems, and provides an air cleaner for a layered scavenging engine that can prevent the mixture from entering the scavenging leading air passage even when the mixture is blown back. It is intended to provide.
[0007]
[Means, actions and effects for solving the problems]
In order to achieve the above object, a first invention of an air cleaner for a stratified scavenging engine according to the present invention provides a scavenging leading air passage and an air-fuel mixture forming air passage in parallel with each other through a body. In an air cleaner of a stratified scavenging engine that supplies clean air to a leading air passage and a mixture formation air passage of a carburetor via an intake passage provided in the body, the air is blown back from the mixture formation air passage. The air-fuel mixture preventing means for preventing the air-fuel mixture from entering the leading air passage through the intake passage is used.
[0008]
According to the above configuration, the mixture mixture prevention means prevents the mixture mixture blown back from the mixture formation air passage from entering the leading air passage. It will not be discharged. Therefore, air pollution can be prevented.
[0009]
The second aspect of the invention is based on the configuration of the first aspect of the invention, wherein the mixture mixture preventing means includes a baffle plate that separates the intake passage into a lead air intake passage and a mixture intake passage, and a body that covers the body. A hollow columnar mixture trap guard provided on the inner surface of the cover that forms an air cleaner chamber therebetween and at a position facing the intake passage for the mixture, and having an opening in the opposite direction to the intake passage for the leading air It has a configuration with.
[0010]
According to the above configuration, since the intake passage is separated into the leading air intake passage and the mixture intake passage by the baffle plate, the blown back mixture is separated from the mixture forming air passage of the carburetor in the intake passage. To prevent contamination. In addition, the air-fuel mixture blown back from the air-fuel mixture intake passage is captured by the air-fuel mixture trapping guard and does not scatter around, and most of the air-fuel mixture is returned to the air-fuel mixture forming air passage using air column vibration. A part of the air leaks from the opening of the air-fuel mixture trapping guard, but the direction of this opening is opposite to the leading air intake passage, and the amount of leakage is small. Therefore, since the amount of air-fuel mixture mixed into the leading air intake passage is reduced, it is possible to prevent air pollution. The intake air to the air-fuel mixture intake passage is performed via the opening of the air-fuel mixture trapping guard, so that the intake air amount does not become insufficient.
[0011]
According to a third aspect of the present invention based on the configuration of the first aspect of the invention, the mixture mixture preventing means includes a baffle plate that separates the intake passage into a lead air intake passage and a mixture intake passage, and a body that covers the body. A cylindrical air-fuel mixture capturing pipe is provided on the inner surface of the cover that forms an air cleaner chamber therebetween and at a position facing the air intake passage for the air-fuel mixture, and has a vent hole in the outer peripheral portion.
[0012]
According to the above configuration, the baffle plate prevents the air-fuel mixture blown back from the air-fuel mixture forming air passage of the carburetor from entering the leading air passage in the intake passage. Further, the air-fuel mixture blown back from the air-fuel mixture intake passage is captured by the air-fuel mixture capturing pipe and does not scatter around, and most of the air-fuel mixture is returned to the air-fuel mixture forming air passage using the air column vibration. A part of it leaks from the vent hole, but the amount is small. Therefore, the amount of air-fuel mixture mixed in the intake passage for leading air is reduced, and air pollution can be prevented. Note that the intake air to the air-fuel mixture intake passage is sucked from the air hole of the air-fuel mixture trapping pipe, so that the intake air amount does not become insufficient.
[0013]
According to a fourth aspect of the present invention based on the configuration of the first aspect of the invention, the mixture mixture preventing means includes a baffle plate that separates the intake passage into a leading air intake passage and a mixture intake passage, and an intake port of the mixture intake passage. And a mixture induction cover having an opening in the opposite direction to the leading air intake passage.
[0014]
According to the above configuration, the baffle plate prevents the air-fuel mixture blown back from the air-fuel mixture forming air passage of the carburetor from entering the leading air passage in the intake passage. Further, the air-fuel mixture blown back from the air-fuel mixture intake passage is prevented from being scattered by the air-fuel mixture induction cover, and from the opening provided on the opposite side of the air-fuel mixture guide cover from the lead air intake passage. Discharged. Accordingly, since the amount of the air-fuel mixture mixed in the leading air intake passage is reduced, air pollution can be prevented.
[0015]
The fifth aspect of the invention is based on the configuration of the first aspect of the invention, wherein the mixture mixture prevention means is rotatably attached to the body and a baffle plate that separates the intake passage into a lead air intake passage and a mixture intake passage. The cylinder is fixed to a choke plate that can open and close the intake passage, and the choke plate includes a cylindrical leading air introduction pipe that communicates with the leading air intake passage in a state where the intake passage is opened.
[0016]
According to the above configuration, the baffle plate prevents the air-fuel mixture blown back from the air-fuel mixture forming air passage of the carburetor from entering the leading air passage in the intake passage. In addition, when the choke plate opens the intake passage (engine operation state), the air-fuel mixture blown back from the air-fuel mixture intake passage is blocked by the lead air introduction pipe, so that the air-fuel mixture mixed in the lead air intake passage The amount is reduced. Therefore, air pollution can be prevented.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of an air cleaner for a stratified scavenging engine according to the present invention will be described in detail with reference to FIGS.
[0018]
FIG. 1 is a side sectional view of a stratified scavenging two-cycle engine 1 provided with an air cleaner 40 according to the first embodiment, and FIG. 2 is a view taken in the direction of arrows AA in FIG. The same components as those of the conventional stratified scavenging two-cycle engine shown in FIG. 9 are denoted by the same reference numerals, description thereof is omitted, and different portions will be described.
1 and 2, a baffle plate 45 that divides the intake passage 42 vertically into two is provided at a substantially central portion of a cylindrical intake passage 42 provided in the body 41 of the air cleaner 40. The baffle plate 45 divides the intake passage 42 into an upper intake air intake passage 46 and a lower mixed air intake passage 47. The leading-air intake passage 46 is connected to the leading-air passage 31 of the carburetor 30, and the air-fuel mixture intake passage 47 is connected to the mixture-forming air passage 32 of the carburetor 30. The cover 43 detachably attached to the body 41 forms an air cleaner chamber between itself and the body 41. In addition, an air-fuel mixture trap guard 48 is fixed on the inner surface of the cover 43 and at a position facing the air-fuel mixture intake passage 47 of the body 41. As shown in FIG. 2, the air-fuel mixture capturing guard 48 has a hollow columnar shape, and an opening 49 is provided below the air-fuel mixture capturing guard 48, that is, on a side surface opposite to the leading air intake passage 46. Yes. In the figure, the mixture trapping guard 48 has a U-shaped cross section, but is not limited to this cross sectional shape. The clearance S between the front end of the air-fuel mixture capturing guard 48 and the front end of the intake passage 42 and the baffle plate 45 is set to a predetermined small value. The baffle plate 45 and the mixture trapping guard 48 constitute a mixture mixture prevention means 44.
[0019]
The operation according to this embodiment will be described.
When air is supplied to the mixture formation air passage 32 of the carburetor 30, the air is sucked from the opening 49 of the mixture capture cover 48. Therefore, there is no shortage of air. The air-fuel mixture blown back from the air-fuel mixture forming air passage 32 of the carburetor 30 when the piston valve is closed collides with the inner surface of the cover 43 through the air-fuel mixture intake passage 47 provided in the body 41 of the air cleaner 40. At this time, the air-fuel mixture that has collided tends to diffuse to the surroundings, but is captured by the air-fuel mixture capturing guard 48 fixed to the inner surface of the cover 43, and part of the air-fuel mixture intake passage again using air column vibration The air-fuel mixture forming air passage 32 is returned to the air-fuel mixture forming passage 32 through 47. A part of the air leaks from the opening 49, but its amount is small, and the direction is opposite to the leading air intake passage 46. Accordingly, the amount of air-fuel mixture mixed into the leading air intake passage 46 is small, and there is little possibility of air-fuel mixture mixing into the exhaust gas and polluting the atmosphere.
[0020]
Next, a second embodiment will be described based on FIGS.
FIG. 3 is a side cross-sectional view of the air cleaner 40a of the second embodiment, and FIG. 4 is a view taken along the line BB of FIG. The same components as those in the first embodiment are denoted by the same reference numerals, description thereof will be omitted, and different components will be described. 3 and 4, the air-fuel mixture supplement having a square cross section is provided on the inner surface of the cover 43 a that covers the body 41 and forms an air cleaner chamber between the body 41 and the air intake passage 47 facing the air-fuel mixture. A pipe 50 is fixed. A plurality of vent holes 51 are provided on one side surface of the air-fuel mixture capturing pipe 50. The clearance S between the tip of the air-fuel mixture capturing pipe 50 and the tip of the intake passage 42 and the baffle plate 45 is set to a small value. The baffle plate 45 and the air-fuel mixture trapping pipe 50 constitute an air-fuel mixture preventing means 44a. In the drawing, the vent hole 51 is provided on the side facing the leading air intake passage 46, but is not limited to this direction and may be provided on the side opposite to the leading air intake passage 46. .
[0021]
According to the above configuration of the present embodiment, when air is supplied to the air-fuel mixture forming air passage 32, the air is sucked through the vent hole 51. Therefore, there is no shortage of air. The air-fuel mixture blown back from the air-fuel mixture forming air passage 32 of the carburetor 30 collides with the inner surface of the cover 43a and tries to scatter around, but the air-fuel mixture capturing pipe 50 prevents the air-fuel mixture from scattering. Most of the air-fuel mixture blown back is returned to the air-fuel mixture forming air passage 32 by using air column vibration, and a part of the air-fuel mixture leaks from the vent hole 51, but the amount is small. Therefore, the amount of air-fuel mixture mixed into the leading air intake passage 46 is small, and the amount of air pollution is reduced.
[0022]
The third embodiment will be described with reference to FIGS.
FIG. 5 is a side sectional view of an air cleaner 40b according to the third embodiment, and FIG. 6 is a view taken along the line CC in FIG. The same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted. 5 and 6, an air-fuel mixture guide cover 55 is fastened to the body 41 by screws 57 at the inlet of the air-fuel mixture intake passage 47 so as to cover the inlet. An opening 56 is provided on the lower surface of the air-fuel mixture induction cover 55, that is, in the direction opposite to the leading air intake passage 46. The baffle plate 45 and the air-fuel mixture guide cover 55 constitute an air-fuel mixture prevention means 44b.
[0023]
The effect | action by the structure of 3rd Embodiment is demonstrated.
When supplying air to the air-fuel mixture forming air passage 32, the air is sucked from the opening 56. Therefore, there is no shortage of air. The air-fuel mixture blown back from the air-fuel mixture forming air passage 32 is not scattered around by the air-fuel mixture induction cover 55. The air-fuel mixture partially leaks from the opening 56, but since the opening 56 faces in the opposite direction to the leading air intake passage 46, the amount of the air-fuel mixture mixed in the leading air intake passage 46 is small, Air pollution can be prevented.
[0024]
Next, a fourth embodiment will be described based on FIGS.
FIG. 7 is a side sectional view of an air cleaner 40c according to the fourth embodiment, and FIG. 8 is a view taken along the line DD in FIG. The same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted. As shown in FIG. 8, a choke plate 60 is attached to the body 41 so as to be rotatable around a pin 62, and the choke plate 60 allows the intake passage 42 to be opened and closed. 7 and 8, the choke plate 60 is fixedly provided with a tubular lead air introduction pipe 61 having a semicircular cross section that communicates with the lead air intake passage 46 when the choke plate 60 is open. Yes. The baffle plate 45 and the leading air introduction pipe 61 constitute an air-fuel mixture preventing means 44c.
[0025]
According to the configuration of the present embodiment, when the engine is started, the operator rotates the choke plate 60 around the pin 62 to close the intake passage 42. When the engine starts, the operator opens the choke plate 60 as shown in FIGS. In this state, since the inlet of the leading air intake passage 46 is surrounded by the leading air introduction pipe 61, even if the air-fuel mixture blows back from the air-fuel mixture forming air passage 32, the air-fuel mixture is mixed into the leading air intake passage 46. The amount of is small. Therefore, air pollution is prevented.
[0026]
As described above, according to the present invention, by providing the mixture mixture prevention means, even if the mixture is blown back from the mixture formation air passage of the carburetor, most of it returns to the mixture formation air passage, Mixing into the leading air passage of the vaporizer is prevented. Therefore, the air-fuel mixture is not mixed with the combustion gas through the leading air passage and discharged into the atmosphere during the exhaust cycle of the stratified scavenging engine. In addition, leakage of the air-fuel mixture blown back to the air cleaner is reduced. Therefore, air pollution can be prevented.
[Brief description of the drawings]
FIG. 1 is a side sectional view of a stratified scavenging two-cycle engine having an air cleaner according to a first embodiment of the present invention.
FIG. 2 is a view taken in the direction of arrows AA in FIG.
FIG. 3 is a side sectional view of an air cleaner according to a second embodiment of the present invention.
4 is a view taken along arrow BB in FIG. 3;
FIG. 5 is a side sectional view of an air cleaner according to a third embodiment of the present invention.
6 is a view taken along the line CC of FIG. 5;
FIG. 7 is a side sectional view of an air cleaner according to a fourth embodiment of the present invention.
FIG. 8 is a view taken along the line DD in FIG.
FIG. 9 is a side sectional view of a stratified scavenging two-cycle engine having an air cleaner according to the prior art.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Stratified scavenging type 2 cycle engine, 30 ... Vaporizer, 31 ... Lead air passage, 32 ... Mixture formation air passage, 40, 40a, 40b, 40c ... Air cleaner, 41 ... Body, 42 ... Intake passage, 43, 43a , 43b ... cover, 44, 44a, 44b, 44c ... mixture mixture preventing means, 45 ... baffle plate, 46 ... leading air intake passage, 47 ... mixture air intake passage, 48 ... mixture trapping guard, 49, 56 DESCRIPTION OF SYMBOLS ... Opening part, 50 ... Mixture capture pipe, 51 ... Ventilation hole, 55 ... Mixture induction cover, 60 ... Choke plate, 61 ... Lead air introduction pipe.

Claims (3)

The intake air provided in the body (41) is attached to the carburetor (30) provided with the leading air passage (31) for scavenging and the mixture formation air passage (32) in parallel through the body (41). In an air cleaner (40) of a stratified scavenging engine that supplies clean air to the leading air passage (31) and the mixture formation air passage (32) of the carburetor (30) via the passage (42),
An air-fuel mixture preventing means (44) for preventing the air-fuel mixture blown back from the air-fuel mixture forming air passage (32) from entering the leading air passage (31) through the intake passage (42) The air pollution prevention means (44) covers the body (41) and the baffle plate (45) that separates the intake passage (42) into the intake air passage (46) for the leading air and the intake passage (47) for the mixture. The inner surface of the cover (43) that forms an air cleaner chamber with the body (41) and at a position facing the air intake passage (47) for the air-fuel mixture, and with respect to the intake air intake passage (46) An air cleaner for a stratified scavenging engine, comprising a hollow columnar mixture trap guard (48) having an opening (49) in the opposite direction . To lead air passage for scavenging (31) and the mixture formed an air passage (32) and the carburetor provided in parallel (30) through the body (41) is attached, provided in the body (41) intake In the air cleaner (40b) of the stratified scavenging engine, which supplies clean air to the leading air passage (31) and the mixture formation air passage (32) of the carburetor (30) via the passage (42) ,
An air- fuel mixture preventing means ( 44b ) for preventing the air- fuel mixture blown back from the air-fuel mixture forming air passage (32) from entering the leading air passage (31) through the intake passage (42) , The air mixing preventing means (44b) includes a baffle plate (45) for separating the intake passage (42) into a lead air intake passage (46) and a mixture air intake passage (47) , and a mixture air intake passage (47 ) provided to cover the suction port, stratified scavenging, characterized in that a mixture derived cover having a (55) opening (56) in the opposite direction to the lead air intake passage (46) Engine air cleaner. To lead air passage for scavenging (31) and the mixture formed an air passage (32) and the carburetor provided in parallel (30) through the body (41) is attached, provided in the body (41) intake In an air cleaner (40c) of a stratified scavenging engine that supplies clean air to the leading air passage (31) and the mixture formation air passage (32) of the carburetor (30) via the passage (42) ,
Mixture formation mixture gas blown back from the air passage (32) is a mixture mixing prevention means to prevent infiltration of the leading air passage (31) through an intake passage (42) (44c), the mixture The air contamination preventing means (44c) rotates on the body (41) and a baffle plate (45) that separates the intake passage (42) into a lead air intake passage (46) and a mixture air intake passage (47). fixed to the choke plate (60) to freely open and close freely attached to an intake passage (42), the choke plate (60) is lead air intake passage in a state of open air passages (42) (46) air cleaner stratified scavenging type engine, characterized in that a cylindrical lead air introduction pipe communicating (61) to.

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