Anti-backflow air filter device and two-stroke stratified scavenging engine

Abstract

This invention provides an anti-backflow air filter device and a two-stroke stratified scavenging engine, relating to the technical field of engines. The anti-backflow air filter device includes an air filter assembly, an air duct, and an anti-backflow baffle assembly. The air filter assembly is connected to the anti-backflow baffle assembly via the air duct. The end of the anti-backflow baffle assembly facing away from the air duct is connected to a stratified scavenging carburetor. The end of the stratified scavenging carburetor facing away from the anti-backflow baffle assembly is connected to a stratified scavenging air intake pipe. The anti-backflow baffle assembly has a straight-through pure air passage and a labyrinthine mixed-air passage. The straight-through pure air passage communicates with the pure air passages of both the stratified scavenging carburetor and the stratified scavenging air intake pipe. The labyrinthine mixed-air passage communicates with the mixed-air passages of both the stratified scavenging carburetor and the stratified scavenging air intake pipe. This achieves the technical effect of reducing the probability of mixed-air backflow.

Description

Technical Field

[0001] This invention relates to the field of engine technology, and more specifically, to an anti-backflow air filter device and a two-stroke stratified scavenging engine. Background Technology

[0002] Two-stroke stratified scavenging engines employ a stratified intake and scavenging logic of "pure air scavenging first, followed by rich mixture combustion," which effectively reduces exhaust emissions and improves fuel economy, making them widely used in various garden machinery and small power equipment. However, during operation, the crankcase scavenging phase involves alternating opening and closing of the intake and scavenging ports, resulting in severe positive pressure pulsation inside the crankcase, which can easily trigger mixture backflow (reverse injection).

[0003] Traditional air intake filter structures lack dedicated anti-backflow and oil mist recovery mechanisms. Backflowing oil mist and air-fuel mixture flow backward from the carburetor into the air filter, subsequently wetting and clogging the sponge and paper filter elements. This significantly shortens filter lifespan, wastes fuel, and causes oil stains on the equipment surface. Furthermore, the backflowing mixture contaminates the pure air used for initial scavenging, disrupting the stratified scavenging effect and directly leading to excessive engine emissions, increased fuel consumption, and a series of other problems, severely impacting engine stability, economy, and environmental performance. Summary of the Invention

[0004] The purpose of this invention is to provide an anti-backflow air filter device and a two-stroke stratified scavenging engine to alleviate the technical problem of easy backflow of air-fuel mixture in the prior art.

[0005] In a first aspect, embodiments of the present invention provide an anti-backflow air filtration device, including an air filter assembly, an air duct, and an anti-backflow baffle assembly; The air filter assembly is connected to the anti-backflow baffle assembly via the air duct. The end of the anti-backflow baffle assembly opposite to the air duct is connected to the stratified scavenging carburetor. The end of the stratified scavenging carburetor opposite to the anti-backflow baffle assembly is connected to the stratified scavenging air intake pipe. The anti-backflow baffle assembly has a straight-through pure air channel and a labyrinthine mixed air channel. The straight-through pure air channel is connected to the pure air channels of both the stratified scavenging carburetor and the stratified scavenging air intake pipe. The labyrinthine mixed air channel is connected to the mixed air channel of both the stratified scavenging carburetor and the stratified scavenging air intake pipe.

[0006] In conjunction with the first aspect, the present invention provides a possible implementation of the first aspect, wherein the above-mentioned anti-backflow baffle assembly includes an air guide seat and an air guide duct; The air duct is inserted into the air guide seat, which has a pure air through hole and a mixer through hole. The pure air through hole is connected to the straight-through pure air channel, and the mixer through hole is connected to the labyrinth-type mixed gas channel.

[0007] In conjunction with the first aspect, the present invention provides a possible implementation of the first aspect, wherein a first partition plate is provided inside the air guide duct, and the first partition plate divides the space inside the air guide seat into the straight-through pure air channel and the labyrinthine mixed gas channel.

[0008] In conjunction with the first aspect, the present invention provides a possible implementation of the first aspect, wherein the aforementioned labyrinthine gas mixing channel has a second partition plate, the second partition plate dividing the labyrinthine gas mixing channel into two symmetrically arranged labyrinthine channels.

[0009] In conjunction with the first aspect, the present invention provides one possible implementation of the first aspect, wherein an anti-backflow plate is provided in the aforementioned maze passage.

[0010] In conjunction with the first aspect, the present invention provides a possible implementation of the first aspect, wherein the second partition plate and the anti-backflow plate are cross-shaped.

[0011] In conjunction with the first aspect, the present invention provides a possible implementation of the first aspect, wherein the air filter assembly includes an air filter base, an air filter cover, and a filter element; The air filter cover is fastened onto the air filter base, and the filter element is disposed inside the air filter base.

[0012] In conjunction with the first aspect, the present invention provides a possible implementation of the first aspect, wherein the filter element includes a sponge filter element disposed within the air filter base.

[0013] In conjunction with the first aspect, the present invention provides a possible implementation of the first aspect, wherein the filter element further includes a paper filter element disposed within the air filter base and located below the sponge filter element.

[0014] Secondly, embodiments of the present invention provide a two-stroke stratified scavenging engine, including the anti-backflow air filter device.

[0015] Beneficial effects: This invention provides an anti-backflow air filtration device, including an air filter assembly, an air duct, and an anti-backflow baffle assembly. The air filter assembly is connected to the anti-backflow baffle assembly via the air duct. One end of the anti-backflow baffle assembly away from the air duct is connected to a stratified scavenging carburetor. The other end of the stratified scavenging carburetor away from the anti-backflow baffle assembly is connected to a stratified scavenging air intake pipe. The anti-backflow baffle assembly has a straight-through pure air channel and a labyrinthine mixed air channel. The straight-through pure air channel communicates with the pure air channels of both the stratified scavenging carburetor and the stratified scavenging air intake pipe. The labyrinthine mixed air channel communicates with the mixed air channels of both the stratified scavenging carburetor and the stratified scavenging air intake pipe.

[0016] Specifically, during use, outside air enters the air filter assembly, then enters the air duct through the air filter assembly, and then enters the engine through the anti-backflow baffle assembly, the stratified scavenging carburetor, and the stratified scavenging intake pipe. The anti-backflow baffle assembly separates pure air from the air-fuel mixture, and the labyrinthine air-fuel mixture passage reduces the probability of air-fuel mixture backflow.

[0017] This invention provides a two-stroke stratified scavenging engine, including an anti-backflow air filter device. The two-stroke stratified scavenging engine has the advantages described above compared to existing technologies, which will not be elaborated further here. Attached Figure Description

[0018] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the anti-backflow air filtration device provided in an embodiment of the present invention; Figure 2 This is a cross-sectional view of the air filter assembly in the anti-backflow air filtration device provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the anti-backflow baffle assembly in the anti-backflow air filter device provided in an embodiment of the present invention; Figure 4 This is a side view of the anti-backflow baffle assembly in the anti-backflow air filter device provided in an embodiment of the present invention; Figure 5 This is an internal schematic diagram of the anti-backflow baffle assembly in the anti-backflow air filter device provided in an embodiment of the present invention; Figure 6 This is a schematic diagram of the air duct in the anti-backflow air filter device provided in an embodiment of the present invention.

[0020] icon: 100 - Air filter assembly; 110 - Air filter base; 120 - Air filter cover; 131 - Sponge filter element; 132 - Paper filter element; 200-Air duct; 300-Anti-backflow baffle assembly; 301-Straight-through pure air passage; 302-Labyrinth mixed air passage; 310-Air guide seat; 311-Pure air through hole; 312-Mixer through hole; 320-Air guide duct; 321-First partition plate; 322-Second partition plate; 323-Anti-backflow plate; 324-Upper baffle wall; 400-Stratified Scavenging Carburetor; 500-Layered scavenging intake pipe. Detailed Implementation

[0021] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0023] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0024] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0025] The present invention will now be described in further detail with reference to specific embodiments and accompanying drawings.

[0026] See Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 and Figure 6 As shown, this embodiment provides an anti-backflow air filtration device, including an air filter assembly 100, an air duct 200, and an anti-backflow baffle assembly 300. The air filter assembly 100 is connected to the anti-backflow baffle assembly 300 via the air duct 200. One end of the anti-backflow baffle assembly 300 away from the air duct 200 is connected to a stratified scavenging carburetor 400. The other end of the stratified scavenging carburetor 400 away from the anti-backflow baffle assembly 300 is connected to a stratified scavenging air intake pipe 500. The anti-backflow baffle assembly 300 has a straight-through pure air channel 301 and a labyrinthine mixed air channel 302. The straight-through pure air channel 301 communicates with the pure air channels of both the stratified scavenging carburetor 400 and the stratified scavenging air intake pipe 500. The labyrinthine mixed air channel 302 communicates with the mixed air channels of both the stratified scavenging carburetor 400 and the stratified scavenging air intake pipe 500.

[0027] Specifically, during use, outside air enters the air filter assembly 100, then enters the air duct 200 through the air filter assembly 100, and then enters the engine through the anti-backflow baffle assembly 300, the stratified scavenging carburetor 400 and the stratified scavenging intake pipe 500. The anti-backflow baffle assembly 300 separates pure air and the mixed gas, and the labyrinth-type mixed gas passage 302 can reduce the probability of backflow of the mixed gas.

[0028] See Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 and Figure 6As shown, in the optional embodiment, the anti-backflow baffle assembly 300 includes an air guide seat 310 and an air guide pipe 320; the air guide pipe 320 is inserted into the air guide seat 310, and the air guide seat 310 is provided with a pure air through hole 311 and a mixer through hole 312. The pure air through hole 311 is connected to the straight pure air channel 301, and the mixer through hole 312 is connected to the labyrinth mixed gas channel 302.

[0029] The air duct 320 is provided with a first partition plate 321, which divides the space inside the air guide seat 310 into a straight pure air channel 301 and a labyrinth mixed gas channel 302.

[0030] The labyrinth-type gas-mixing channel 302 has a second partition plate 322, which divides the labyrinth-type gas-mixing channel 302 into two symmetrically arranged labyrinth channels.

[0031] Among them, anti-backflow spray plates 323 are installed in the maze passage.

[0032] The second partition plate 322 and the anti-backflow plate 323 are cross-shaped.

[0033] Specifically, clean air filtered by the air filter assembly 100 is smoothly delivered to the interior of the anti-backflow baffle assembly 300 through the rubber air duct 200. The air duct 320 and the air duct 320 seat of the anti-backflow baffle assembly 300 are sealed together, forming three functionally independent air intake cavities: a straight-through pure air passage 301 and symmetrically arranged labyrinth passages. The airflow in the straight-through pure air passage 301 reaches the pure air passage of the carburetor without obstruction, providing high-purity air for the engine's initial stratified scavenging. The symmetrically arranged labyrinth passages are divided into two independent chambers at the top by a cross-shaped second partition plate 322 and an anti-backflow baffle plate 323 inside the air duct 320, while the lower chambers are interconnected and merge. Here, the clean air is fully mixed with the fuel mist sprayed from the carburetor to form a uniform mixture, which is then delivered into the engine through the mixed air passage of the stratified scavenging air intake pipe 500, completing the stratified air intake operation.

[0034] In addition, during engine scavenging, when the mixture is sprayed back due to the positive pressure pulsation of the crankcase, the reverse flow of oil mist and mixture flows into the lower part of the two labyrinth channels from the carburetor. The oil mist mixture is first intercepted by the side wall of the air guide seat 310, which directly blocks and turns back most of the reverse flow of oil mist mixture. The small amount of mixture that is not completely intercepted goes up along the labyrinth cavity and is blocked by the anti-backflow plate 323 in the middle of the air guide 320, achieving a second strong interception. This ensures that most of the remaining mixture is blocked, and only a very small amount of oil mist mixture can continue to go up. Finally, it is completely intercepted by the upper blocking wall 324 of the air guide 320, and only a trace amount of oil and gas can overflow through the top air intake.

[0035] It should be noted that the anti-backflow air filter device provided in this embodiment, through the labyrinthine mixing channel 302, ensures that when a trace amount of oil mist mixture overflows, the engine piston has simultaneously entered the upper stroke, and the negative pressure inside the crankcase continues to increase. Fresh outside air will quickly flow into the labyrinthine channel through the air inlet of the air duct, re-entraining the overflowing trace amount of oil mist mixture into the carburetor mixing channel, where it will participate in combustion again. Throughout the entire recovery process, the airflow in the straight-through pure air channel 301 is completely independent and unaffected by the mixture, always ensuring the cleanliness of the initial scavenging pure air, precisely matching the stratified scavenging logic of the two-stroke engine.

[0036] It should also be noted that the anti-backflow air filter device provided in this embodiment solves the industry pain points such as air-fuel mixture backflow, filter blockage, high fuel consumption, excessive emissions, and unstable idling speed of traditional two-stroke stratified scavenging engines from the root by combining an independent layered air intake structure with a multi-stage labyrinth barrier and negative pressure self-recovery anti-backflow system. The structure is simple and compact, requires no additional power components, has low intake resistance, and is widely adaptable, which can effectively improve the engine's fuel economy, operational stability, and service life.

[0037] See Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 and Figure 6 As shown, in an optional embodiment, the air filter assembly 100 includes an air filter base 110, an air filter cover 120, and a filter element; the air filter cover 120 is fastened to the air filter base 110, and the filter element is disposed inside the air filter base 110.

[0038] The filter element includes a sponge filter element 131, which is disposed inside the air filter base 110.

[0039] The filter element also includes a paper filter element 132, which is disposed inside the air filter base 110 and located below the sponge filter element 131.

[0040] Specifically, the air filter assembly 100 is an external air filter. The air filter assembly 100 adopts a dual-layer staged filtration structure. In actual operation, the outside air first passes through the sponge filter element 131 to complete coarse filtration, which efficiently intercepts large particulate impurities such as leaves, dust, and debris. Then, the coarsely filtered air continues to flow through the paper filter element 132. The paper filter element 132 can accurately filter fine dust, suspended impurities, and water vapor in the air, thoroughly purifying the intake airflow, providing clean intake air for the engine, and preventing impurities from wearing down internal engine parts.

[0041] In addition, the sponge filter element 131 can be selected with a single uniform mesh structure or a coarse and fine double-layer composite structure, depending on the working conditions.

[0042] This embodiment provides a two-stroke stratified scavenging engine, including an anti-backflow air filter device.

[0043] Specifically, the two-stroke stratified scavenging engine provided in this embodiment has the advantages of the aforementioned anti-backflow air filter device compared with the prior art, which will not be elaborated here.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An anti-backflow air filtration device, characterized in that, include: Air filter assembly (100), air duct (200) and anti-backflow baffle assembly (300); The air filter assembly (100) is connected to the anti-backflow baffle assembly (300) via the air duct (200). The end of the anti-backflow baffle assembly (300) away from the air duct (200) is connected to the stratified scavenging carburetor (400). The end of the stratified scavenging carburetor (400) away from the anti-backflow baffle assembly (300) is connected to the stratified scavenging air intake pipe (500). The anti-backflow baffle assembly (300) has a straight-through pure air passage (301) and a labyrinthine mixed air passage (302). The straight-through pure air passage (301) is connected to the pure air passages of both the stratified scavenging carburetor (400) and the stratified scavenging air intake pipe (500). The labyrinthine mixed air passage (302) is connected to the mixed air passages of both the stratified scavenging carburetor (400) and the stratified scavenging air intake pipe (500).

2. The anti-backflow air filtration device according to claim 1, characterized in that, The anti-backflow baffle assembly (300) includes an air guide seat (310) and an air guide duct (320). The air duct (320) is inserted into the air guide seat (310). The air guide seat (310) has a pure air through hole (311) and a mixer through hole (312). The pure air through hole (311) is connected to the straight pure air channel (301), and the mixer through hole (312) is connected to the labyrinth mixed gas channel (302).

3. The anti-backflow air filtration device according to claim 2, characterized in that, The air duct (320) is provided with a first partition plate (321), which divides the space inside the air guide seat (310) into the straight pure air channel (301) and the labyrinth mixed gas channel (302).

4. The anti-backflow air filtration device according to claim 3, characterized in that, The labyrinthine gas mixing channel (302) has a second partition plate (322) that divides the labyrinthine gas mixing channel (302) into two symmetrically arranged labyrinthine channels.

5. The anti-backflow air filtration device according to claim 4, characterized in that, The maze passage is equipped with anti-backflow spray plates (323).

6. The anti-backflow air filtration device according to claim 5, characterized in that, The second partition plate (322) and the anti-backflow plate (323) are cross-shaped.

7. The anti-backflow air filtration device according to claim 1, characterized in that, The air filter assembly (100) includes an air filter base (110), an air filter cover (120), and a filter element; The air filter cover (120) is fastened to the air filter base (110), and the filter element is disposed inside the air filter base (110).

8. The anti-backflow air filtration device according to claim 7, characterized in that, The filter element includes a sponge filter element (131), which is disposed inside the air filter base (110).

9. The anti-backflow air filtration device according to claim 8, characterized in that, The filter element also includes a paper filter element (132), which is disposed inside the air filter base (110) and is located below the sponge filter element (131).

10. A two-stroke stratified scavenging engine, characterized in that, Includes the anti-backflow air filter device as described in any one of claims 1-9.

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