JP2016006326A - Intake system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique relating to an internal combustion engine air filter.SOLUTION: An air intake system (100) for an internal combustion engine comprises: an air filter (1); and flow resistance means (2). The air filter (1) includes: one or a plurality of filter elements (12); an internal chamber (3); and an intake opening portion (6). The intake opening portion (6) is provided to connect the internal chamber (3) to an intake channel (7) of the internal combustion engine. At a time of actuating the internal combustion engine, combustion air flows into the internal chamber (3) via the one or plurality of filter elements (12) and into the intake channel (7) from the internal chamber (3). Furthermore, the internal chamber (3), the intake opening portion (6), and the intake channel (7) collectively define a combustion air channel. The flow resistance means (2) is provided in this combustion air channel. At the time of actuating the internal combustion engine, part of the combustion air flows through the flow resistance means (2).

Description

  The present invention relates to an air filter for an internal combustion engine, and more particularly, the present invention relates to a two-cycle internal combustion engine used for a handheld power tool such as a power saw or a trimmer, without limitation.

  Two-cycle internal combustion engines are widely used for handheld power tools. Usually, a two-cycle internal combustion engine includes an air filter provided in an intake channel of the internal combustion engine. The air filter is essential to ensure proper operation of the internal combustion engine. The air filter captures dust and other particulate matter present in the combustion air, and thereby supplies clean air to the internal combustion engine. Typically, an air filter includes an internal chamber, one or more filter elements, and an intake opening for connecting the air filter to an intake channel of an internal combustion engine. During operation of the internal combustion engine, combustion air enters the internal chamber through one or more filter elements and further enters the intake channel of the internal combustion engine through the intake opening.

  As is well known in the art, in a two-cycle internal combustion engine, the intake channel is further connected to a crankcase or cylinder. During operation of the internal combustion engine, a mixture of unburned fuel and lubricant present in the crankcase may flow back into the intake channel. The backflow of unburned fuel and lubricant mixture from the crankcase into the intake channel is called backflow or backspit. In the case of a two-cycle internal combustion engine that does not have a system for controlling backflow or backspit, a mixture of unburned fuel and lubricant will quickly plug and clog the air filter, As a result, it is necessary to clean or replace the air filter very frequently.

  Usually, the cost of the air filter is low, and its replacement is performed together with other maintenance work, and is not very troublesome work. However, in the case of power tools used in dusty environments such as applications that require high performance, industrial applications, and agricultural applications, the cost of air filter replacement may increase. And as a result, significant improvements in filter performance and lifetime are required. In the prior art, a valve may be used in the crankcase and / or the suction channel to minimize backflow. However, the design and installation of such a valve is rather complicated and expensive.

  Accordingly, there is a need for a means for improving the service life of a two-cycle internal combustion engine and, in particular, an air filter, by controlling the backflow in the two-cycle internal combustion engine. Furthermore, there is a need for a means for controlling the flow of combustion air in the air filter intake direction.

  In view of the above contents, the object is to solve or at least reduce the above-mentioned problems. In particular, the object is to provide an improved air intake system for a two-cycle internal combustion engine used in power tools. This air suction system has a simple design and prevents blockage of the air filter due to backflow or backspit.

  This object is achieved by a new air suction system, which includes an air filter and flow resistance means. The air filter includes one or more filter elements, an internal chamber, and a suction opening. The intake opening is provided for connecting the internal chamber to the intake channel of the internal combustion engine. During operation of an internal combustion engine, combustion air flows through one or more filter elements into the internal chamber and from the internal chamber into the intake channel. Furthermore, the internal chamber, the intake opening, and the intake channel define a combustion air flow path, and a flow resistance means is provided in the combustion air flow path. During operation of the internal combustion engine, a portion of the combustion air flows through the flow resistance means. The portion of combustion air flowing through the flow resistance means may range from 20% to 100%, which is at least 20%, 30%, 40%, 50%, 60%, 70% of the combustion air, It means 80%, or at least 90%, or in some cases 100% of the combustion air.

  Preferably, the flow resistance means may absorb unburned fuel and / or lubricant during reverse flow through the combustion air path from the internal combustion engine. As a result, the flow resistance means will prevent unburned fuel and lubricant from reaching one or more filter elements, thereby blocking the filter elements due to backflow or backspits. Avoided.

  A combustion air flow path defined between the internal chamber, the intake opening, and the intake channel has a cross-sectional area located in a plane substantially transverse to the average flow direction of the combustion air. Furthermore, the flow resistance means is at least 30% of this cross-sectional area, such as at least 40%, 50%, 60%, 80%, or at least 90%, or in some cases 100% of this cross-sectional area. May cover at least 70%.

  This air intake system may be used in a two-cycle internal combustion engine. The two-cycle internal combustion engine includes an air supply passage that connects the internal chamber to one or more transfer ducts of the internal combustion engine and supplies additional air to the one or more transfer ducts. . A portion of this additional air may flow through the flow resistance means. The portion of additional air that flows through the flow resistance means is 10% of the additional air, such as at least 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, or 90%. % To 100%. Alternatively, the additional air may not flow through the flow resistance means.

  The flow resistance means may comprise a plastic or rubber foam or, in some cases, a metal structure. Further, the foam / metal structure may extend in the direction of combustion air flow by at least 2 mm to at least 3 mm, and the average cell diameter of the foam / metal structure is about 1000 μm to 3000 μm. Range. Further, the foam / metal structure may extend in the direction of combustion air flow by at least 3 mm to at least 4 mm, and the average cell diameter of the foam / metal structure is about 3000 μm to 5000 μm. Range. Further, the foam / metal structure may extend in the direction of combustion air flow by at least 4 mm to at least 5 mm, and the average cell diameter of the foam / metal structure is about 5000 μm to 8000 μm. Range.

  The average cell diameter of the foam / metal structure may range from about 2000 μm to 7000 μm, and the foam / metal structure is disposed within the internal chamber of the air filter. Furthermore, the air filter may include a housing for housing the internal chamber. The housing is formed from one or more housing shells. One housing shell may include one or more filter elements, and another housing shell may include an intake opening. The foam / metal structure may be attached to a housing shell that includes one or more filter elements. However, in certain embodiments, the foam / metal structure may be attached to a housing shell that includes a suction opening.

The foam may be made from a polyester material and the average density of the polyester material may be in the range of 20 kg / cm ^{3 to} 50 kg / m ³ . Further, the filter element may be made from plastic or rubber foam, nylon mesh, or felt.

  The present invention also provides a method for inhaling combustion air into an internal combustion engine. The method may include providing a plastic or rubber foam or, optionally, a metal structure in the combustion air flow path. The method further includes inhaling a portion of the combustion air through the foam. The portion of combustion air that passes through the foam or metal structure may be at least 30% or at least 40% of the combustion air. Preferably, the portion of combustion air that passes through the foam may be at least 50%, 60%, 70%, 80%, 90%, or in some cases 100%.

  The foam / metal structure may have an average cell diameter in the range of 2000 μm to 7000 μm, such as 3000-6000 μm, and preferably 3800-5200 μm.

  Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

1 shows a cross-sectional view of an air intake system 100 for an internal combustion engine according to an embodiment of the present invention. The perspective view of the 1st housing shell 4 of the air filter of an internal-combustion engine by one embodiment of the present invention is shown. The front view of the 2nd housing shell 5 of the air filter of the internal combustion engine by one Embodiment of this invention is shown.

  Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings showing preferred embodiments of the present invention. In the present specification, however, the present invention has been implemented in a number of different forms, and these embodiments are intended to ensure that the present disclosure is sufficient and complete, and that the scope of the present invention will be understood by those skilled in the art. Provided to communicate well. In the accompanying drawings, the same reference numerals denote the same reference contents.

  FIG. 1 shows a cross-sectional view of an air intake system 100 for an internal combustion engine according to an embodiment of the present invention. The air intake system 100 supplies combustion air to the internal combustion engine. While this exemplary embodiment is shown as being used in connection with an internal combustion engine, the present invention can be incorporated into any suitable type of internal combustion engine or device, And it should be understood that the invention is not limited to use in internal combustion engines and may be incorporated into various types of embodiments. The internal combustion engine may generally be a gasoline internal combustion engine or a diesel internal combustion engine. Usually, an internal combustion engine includes a crankcase and at least one cylinder. The piston can reciprocate in the cylinder and is connected to the crankshaft via a connecting rod. In various embodiments of the present invention, the internal combustion engine may be a two-cycle internal combustion engine for handheld work tools such as chainsaws, power cutters, and trimmers.

  An air intake system 100 for an internal combustion engine includes an air filter 1 and a flow resistance means 2. The air filter 1 includes a housing and at least one filter element (not shown in FIG. 1). The housing may house the internal chamber 3. In one embodiment of the present invention, the housing may be composed of a first housing shell 4 and a second housing shell 5. In another embodiment of the present invention, the first housing shell 4 includes at least one filter element and the second housing shell 5 includes a suction opening 6. The suction opening 6 connects the internal chamber 3 to the suction channel 7 of the internal combustion engine. Combustion air flows into the internal chamber 3 through the at least one filter element 12 and thus from the internal chamber 3 through the intake opening 6 into the intake channel 7. The internal chamber 3, the intake opening 6, and the intake channel 7 cooperate to define a combustion air flow path. The flow resistance means 2 is disposed in the combustion air flow path. The housing shells 4 and 5 may include one or more holes (not shown in FIG. 1) for inserting a retaining screw. For example, a screw 8 may be provided to fix the first housing shell 4 to the second housing shell 5. Screws 8 are inserted into corresponding holes present in the first and second housing shells 4 and 5.

  The minimum percentage of combustion air that passes through the flow resistance means 2 is hereinafter referred to as the first threshold percentage. The first threshold percentage may depend on the design of the flow resistance means 2. In one embodiment of the invention, the first threshold percentage may be at least 20%. In a preferred embodiment of the present invention, the first threshold percentage may be at least 30%. In another preferred embodiment of the present invention, the first threshold percentage may be at least 40%. Further, in various embodiments of the present invention, the first threshold percentage may range from 50-100%, such as at least 60%, 70%, 80%, or 90%.

  In the intake phase of the internal combustion engine cycle, combustion air is drawn through the air intake system 100 and mixed with fuel to form a combustible mixture. This combustible mixture may be formed in the fuel supply unit 9, which may be a carburetor.

  Further, the choke valve 10 may be provided to change the air pressure in the air intake system 100 of the internal combustion engine, thereby changing the ratio of the amount of fuel and air entering the internal combustion engine. When starting the internal combustion engine, the choke valve 10 may be used to supply a rich fuel-air mixture. Furthermore, a throttle valve 11 may be provided downstream of the choke valve 10 in order to adjust the amount of the fuel-air mixture entering the internal combustion engine.

  By igniting the combustible mixture in the internal combustion engine, the piston is driven during the starting stroke of the internal combustion engine cycle. In particular, during the starting stroke, a part of unburned fuel and / or lubricant may flow back to the air intake system 100 together with combustion air. This fuel-air mixture escaping into the air intake system 100 and unburned fuel and / or lubricant is commonly referred to as backflow or backspit.

  In one embodiment of the invention, the flow resistance means 2 absorbs fuel and / or lubricant that flows backward from the internal combustion engine. More specifically, the backspit flowing toward the air filter 1 along the combustion air flow path must pass through the flow resistance means 2. As a result, the flow of fuel and / or lubricant is prevented from reaching one or more filter elements 12 of the air filter 1 and, as a result, the service life of the air filter 1 is improved.

  Furthermore, in various embodiments of the present invention, fuel and / or lubricant absorbed in the flow resistance means 2 may be withdrawn back to the internal combustion engine during the intake phase of the internal combustion engine. As a result, the fuel and / or lubricant present in the backflow from the internal combustion engine is efficiently utilized.

  The flow resistance means 2 is arranged in the combustion air flow path defined by the internal chamber 3, the suction opening 6 and the suction channel 7. The combustion air flow path has a cross-sectional area located in a plane substantially transverse to the average flow direction of the combustion air. The minimum percentage of the cross-sectional area covered by the flow resistance means 2 is hereinafter referred to as the second threshold percentage. In one embodiment of the invention, the second threshold percentage may be at least 30%. In a preferred embodiment of the present invention, the second threshold percentage may be at least 50%. In another preferred embodiment of the present invention, the second threshold percentage may be at least 70%. Also, the second threshold percentage may be at least 40%, 60%, 80%, 90%, or in some cases at least 95%.

  FIG. 2 shows a perspective view of the first housing shell 4 of the air filter 1 according to an exemplary embodiment of the invention. As shown in FIG. 2, the first housing shell 4 includes a plurality of filter elements 12 and flow resistance means 2. Holes 13 may be provided to secure the first housing shell 4 to the second housing shell 5 (this is shown in FIG. 3). In one embodiment of the invention, each of the filter elements 12 may be made from plastic or rubber foam, nylon mesh, or felt.

  In one embodiment of the present invention, the flow resistance means 2 may be a plastic or rubber foam or a metal structure. Furthermore, in various embodiments of the present invention, the flow resistance means 2 may extend in the flow direction of the combustion air. In one embodiment of the invention, the flow resistance means 2 may extend in the flow direction of the combustion air by at least 2 mm, and preferably by at least 3 mm, and the average of the flow resistance means 2 The cell diameter may range from 1000 to 3000 μm. In another embodiment of the invention, the flow resistance means 2 may extend in the flow direction of the combustion air by at least 4 mm, and preferably more than 5 mm, and the flow resistance means 2 The average cell diameter may range from 3000 to 5000 μm. Furthermore, in various embodiments of the invention, the flow resistance means 2 may extend in the direction of combustion air flow by at least 4 mm, and preferably by more than 5 mm, and the flow resistance. The average cell diameter of the means 2 may be in the range of 5000 to 8000 μm.

  In one embodiment of the present invention, the average cell diameter of the flow resistance means 2 may be in the range of 2000-7000 μm. In a preferred embodiment of the present invention, the average cell diameter of the flow resistance means 2 may be in the range of 3000-6000 μm. Furthermore, in another preferred embodiment of the present invention, the average cell diameter of the flow resistance means 2 may be in the range of 3800-5200 μm. In one embodiment of the invention, the flow resistance means 2 may be disposed in the internal chamber 3. The flow resistance means 2 may preferably be arranged in the vicinity of the air filter 1 or inside the air filter 1. As shown in FIG. 2, the flow resistance means 2 may be attached to a first housing shell 4 that includes a filter element 12. However, in another embodiment of the present invention, the flow resistance means 2 may be mounted on the second housing shell 5 including the suction opening 6.

Furthermore, in one embodiment of the invention, the flow resistance means 2 may be a foam made from a polyester material. However, those skilled in the art will appreciate that the flow resistance means 2 may be manufactured from other materials. In one embodiment of the present invention, the average density of the flow resistance means 2 may be in the range of 20-50 kg / m ³ . In a preferred embodiment of the invention, the average density of the flow resistance means 2 may be in the range of 23 to 35 kg / m ³ .

  FIG. 3 shows a front view of the second housing shell 5 of the air filter 1 according to an illustrative embodiment of the invention. The second housing shell 5 has a plurality of holes 14 for inserting retaining screws for fixing the second housing shell 5 to, for example, a fuel supply unit 9 such as a carburetor (shown only in FIG. 1). May be included. This screw 8 may pass through a hole 13 (shown only in FIG. 2) in the first housing shell 4 and a corresponding hole in the second housing shell 5. In an alternative configuration, the air filter is not directly attached to the fuel supply unit. In this case, at least one separate tube for directing combustion air and / or additional air may be present between the air filter and the fuel supply unit. This may be advantageous due to space limitations or other reasons. As shown in FIG. 3, the flow resistance means 2, which can be a plastic or rubber foam or metal structure, is mounted on the second housing shell 5. Furthermore, the suction channel 7 may extend into the inner chamber 3 (see FIG. 1) and terminate in a semicircular wall 18 (also shown in FIG. 1). Good. The flow resistance means 2 is provided in the combustion air flow path so that the internal combustion engine sucks air through the flow resistance means 2. Combustion air is sucked into the suction channel 7 after passing through the flow resistance means 2, as indicated by arrow 15. The combustion air is preferably guided by each wall of the first housing shell 4 and / or the second housing shell 5, such as a semicircular wall 17, so that the combustion air is shown in FIG. Thus, substantially entering the extending inhalation channel from above. According to a preferred configuration of the invention, the combustion air may be guided such that at most 100% of the combustion air flows through the flow resistance means 2.

  In one embodiment of the present invention, the internal combustion engine may be a crankcase scavenging two-cycle internal combustion engine having an air supply passage 16. The air supply passage may connect the internal chamber 3 to one or more transfer ducts (not shown) of the internal combustion engine. In further embodiments of the present invention, an air valve 17 may be provided in the air supply passage 16 to adjust the amount of air entering one or more transfer ducts. The air supply passage supplies additional air to one or more transfer ducts of the internal combustion engine via a port controlled by the piston during a pressure drop in the crankcase. As a result, external air can be temporarily stored in one or more transfer ducts and a combustion chamber in communication with one or more transfer channels is supplied with an air / fuel mixture. Before doing so, it can be purified by external air. Purifying means removing a very small amount of unburned fuel from the internal combustion engine. In one embodiment of the invention, additional air may flow through the flow resistance means 2. The minimum percentage of additional air flowing through the flow resistance means 2 is hereinafter referred to as the third threshold percentage. In one embodiment of the invention, the third threshold percentage may be at least 10% or at least 20%. In an alternative embodiment of the invention, the third threshold percentage may be at least 30% or at least 40%. In another alternative embodiment of the invention, the third threshold percentage is at least 50%, such as at least 60%, 70%, 80%, or 90%, or in some cases 100%, etc. Good. Furthermore, in a preferred embodiment of the invention, additional air may not flow through the flow resistance means 2.

  The accompanying drawings and this specification disclose preferred embodiments and examples of the present invention, and specific terms are employed, but these terms are intended to have a general and explanatory meaning. And therefore is not intended to be limiting and the scope of the invention is as set forth in the appended claims.

Claims (21)

An air suction system (100) for a crankcase scavenging two-cycle internal combustion engine comprising:
An air filter (1) comprising at least one filter element (12);
An internal chamber (3);
An intake opening (6) for connecting the internal chamber (3) to the intake channel (7) of the internal combustion engine,
Combustion air flows into the internal chamber (3) through the at least one filter element (12) and from the internal chamber (3) through the intake opening (6) into the intake channel (7); and
The internal combustion engine is provided with an air supply passage (16) connecting the internal chamber (3) with the at least one transfer duct of the internal combustion engine for supplying additional air to the at least one transfer duct;
The air suction system (100) further comprises flow resistance means (2),
The internal chamber (3), the suction opening (6), and the suction channel (7) define a combustion air flow path,
At least 30% of the combustion air flows through the flow resistance means (2), whereby the flow resistance means (2) flows back from the internal combustion engine toward the at least one filter element (12) through the combustion air flow path. The flow resistance means (2) is for combustion purposes so as to absorb the fuel and / or lubricant and thereby prevent the fuel and / or lubricant from reaching the at least one filter element (12). A plastic or rubber foam placed in the air flow path;
An air suction system (100), wherein flow resistance means (2) is disposed in the internal chamber (3).   2. Air intake system (100) according to claim 1, characterized in that at least 50% of the combustion air flows through the flow resistance means (2).   3. An air intake system (100) according to claim 2, characterized in that at least 80% of the combustion air flows through the flow resistance means (2).   The combustion air flow path has a cross-sectional area located in a plane substantially transverse to the average flow direction, and the flow resistance means (2) covers at least 30% of the cross-sectional area. The air inhalation system (100) according to any one of claims 1 to 3.   5. Air intake system (100) according to any one of the preceding claims, characterized in that at least 10% of the additional air flows through the flow resistance means (2).   Air intake system (100) according to any one of the preceding claims, characterized in that no additional air flows through the flow resistance means (2).   7. The flow resistance means (2) extends in the flow direction of the fuel air by at least 2 mm, and the foam has an average cell diameter of 1000 to 3000 [mu] m. An air inhalation system (100) according to claim 1.   7. The flow resistance means (2) extends in the flow direction of the combustion air by at least 3 mm, and the foam has an average cell diameter of 3000 to 5000 [mu] m. An air inhalation system (100) according to any one of the preceding claims.   7. The flow resistance means (2) extends in the flow direction of the combustion air by at least 4 mm and the foam has an average cell diameter of 5000 to 8000 [mu] m. An air inhalation system (100) according to any one of the preceding claims.   The air suction system (100) according to any one of claims 1 to 6, characterized in that the average cell diameter of the flow resistance means (2) is in the range of 2000 to 7000 µm.   The air filter (1) includes a housing that houses an internal chamber (3), the housing being formed from at least one housing shell (4, 5), at least one of these housing shells (4 5. Air intake system (100) according to claim 1, characterized in that 5) comprises at least one filter element (12).   The air intake system (100) according to claim 11, characterized in that one housing shell (4, 5) comprises an intake opening (6).   13. Air suction system (100) according to claim 11 or 12, characterized in that the flow resistance means (2) is mounted on a housing shell (4, 5) comprising at least one filter element (12).   14. Air suction system (100) according to claim 12 or 13, characterized in that the flow resistance means (2) is mounted on a housing shell (4, 5) comprising a suction opening (6).   15. Air suction system (100) according to any one of the preceding claims, characterized in that the flow resistance means (2) is a foam made from a polyester material. Flow resistance means (2), the air inlet system (100) according to any one of claims 1 to 15, characterized in that it has an average density of 20 to 50 kg / m ^3.   The air suction system (100) according to any one of the preceding claims, characterized in that the filter element (12) is manufactured from plastic or rubber foam, nylon mesh or felt. A method for drawing combustion air into a crankcase scavenging two-cycle internal combustion engine, wherein the internal combustion engine has an internal chamber (3) for supplying additional air to at least one transfer duct. An air supply passage (16) connected to two transfer ducts, comprising:
Providing a flow resistance means (2) in the form of a plastic or rubber foam in an internal chamber (3) in the combustion air flow path;
Inhaling at least 30% of the combustion air through the foam, the combustion air flow path extending between the air filter element (12) and the fuel supply unit (9) of the internal combustion engine; ,
Absorbing fuel and / or lubricant backflowing from the internal combustion engine toward the filter element (12) through the combustion air flow path by means of flow resistance means (2);
Thereby preventing fuel and / or lubricant from reaching the filter element (12);
A method characterized by comprising:   The method of claim 18, wherein at least 40% of the combustion air is inhaled through the foam.   The method of claim 19, wherein at least 70% of the combustion air is inhaled through the foam.   21. A method according to any one of claims 18 to 20, wherein the foam has an average cell diameter of 2000 to 7000 [mu] m.

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