An intake system for a general-purpose engine

Abstract

This utility model discloses an intake system for a general-purpose engine, including an air filter and an air-fuel mixing device. An intake pipe connects the outlet of the air filter to the inlet of the air-fuel mixing device. Inside the intake pipe, an intake channel and a guide channel are sequentially arranged along the airflow path. The guide channel is curved, with a smooth transition between its inlet and outlet ends. The outlet end of the guide channel faces the inlet of the air-fuel mixing device. A guide groove extending along the airflow path is provided on the outer circumference of the guide channel, with its end gradually extending towards the inner circumference of the guide channel. This solution provides an intake system, different from existing technologies, that addresses the problem of uniform air-fuel mixing.

Description

Technical Field

[0001] This utility model relates to the intake system of a general-purpose engine. Background Technology

[0002] The intake system of a general-purpose engine refers to the system that filters and mixes fresh outside air with fuel spray to form a fuel-air mixture that is then delivered into the engine cylinders for combustion. The intake system mainly consists of an air filter, a fuel-air mixing unit, and corresponding piping. In existing technology, the air filter is typically located above the fuel-air mixing unit, and the two are connected by piping. With increasingly stringent emission regulations, further improving the performance of the intake system to better meet environmental emission requirements has become a pressing issue.

[0003] Chinese patent document CN217602802U discloses an intake system for supplying air to an engine, including an air filter, a vent pipe, a throttle valve, and an intake manifold; the two ends of the vent pipe are smoothly transitioned and connected to the air outlet of the air filter and the air inlet of the throttle valve, the air outlet of the throttle valve is connected to the air inlet of the intake manifold, and the air outlet of the intake manifold is connected to the air inlet of the engine; the air outlet of the vent pipe, the throttle valve, and the air inlet of the intake manifold are all horizontally arranged; a fuel injector is connected to the intake manifold. The advantages of this prior art are as follows: Since the air outlet of the vent pipe, the throttle body, and the air inlet of the intake pipe are all horizontally arranged, it facilitates the uniform entry of airflow into the throttle body and the vent pipe. Furthermore, because the airflow entering the throttle body is uniform, the accuracy of the gas velocity detected by the detector within the throttle body is improved, which in turn facilitates the improvement of the accuracy of the fuel injection quantity, thereby improving the uniformity of gas-fuel mixing. In addition, since both ends of the vent pipe are smoothly transitioned and connect the air outlet of the air filter and the air inlet of the throttle body, the resistance encountered by the gas output from the air filter as it flows through the vent pipe is reduced, further improving the uniformity of airflow entering the throttle body, further improving the uniformity of gas-fuel mixing, and ensuring complete fuel combustion.

[0004] Although the aforementioned prior art improves the uniformity of gas-oil mixing in the intake system, the technical means employed require the vent pipe to be arranged in a spiral shape, and there are certain requirements on the orientation of the air filter outlet, throttle valve, and intake pipe inlet, which limits the use of the prior art intake system. Utility Model Content

[0005] The purpose of this invention is to provide an alternative intake system for general-purpose engines that differs from existing technologies and addresses the problem of uniform mixing of gas and fuel gas.

[0006] To achieve the above objectives, the basic solution of this utility model provides an intake system for a general-purpose engine, including an air filter and an air-fuel mixing device. An intake pipe is connected between the outlet of the air filter and the inlet of the air-fuel mixing device. An intake channel and a guide channel are sequentially arranged inside the intake pipe along the airflow path. The guide channel is curved, and the inlet end of the guide channel and the outlet end of the intake channel are smoothly transitioned. The outlet end of the guide channel is positioned directly opposite the inlet of the air-fuel mixing device. A guide groove extending along the airflow path is provided on the outer circumference of the guide channel, and the end of the guide groove gradually extends toward the inner circumference of the guide channel.

[0007] The beneficial effects of this basic scheme are as follows: After being filtered by the air filter, the air enters the intake channel of the intake pipe through the air outlet. Then, the air changes its flow direction through the guide channel and enters the oil-gas mixing device directly through the air inlet. When the air changes its flow direction through the guide channel, the air flowing from the outer circle of the guide channel will flow towards the inner circle of the guide channel after passing through the guide groove. Through trial verification, the uniformity of air mixing with fuel gas after entering the oil-gas mixing device is significantly improved.

[0008] Preferably, the starting end of the guide groove is tangential to the side wall of the air intake channel. This arrangement allows air to flow smoothly as it enters the guide groove from the air intake channel, reducing kinetic energy loss.

[0009] Preferably, the depth of the guide groove gradually increases and then gradually decreases from the starting end to the ending end. This arrangement creates a flow channel with a gradually changing cross-section, preventing high-speed airflow from generating pulsating noise due to drastic kinetic energy release or low-frequency booming noise due to pressure changes when flowing through the channel.

[0010] Preferably, the cross-sectional area of ​​the intake channel gradually decreases along the airflow path. The position where the intake channel connects to the air filter is eccentrically located at the end where the intake pipe connects to the air filter. The exhaust end of the intake channel is eccentrically located relative to the end where the intake pipe connects to the air filter. Furthermore, the positions of the exhaust end of the intake channel and the air filter connection are located on either side of the centerline of the end where the intake pipe connects to the air filter. The exhaust direction of the guide channel is directed towards the centerline of the end where the intake pipe connects to the air filter. This configuration causes the air velocity to gradually increase as the air flows through the intake channel, and some of the airflow in the intake channel is compressed towards the side of the intake channel connected to the outer circle of the guide channel. As the air flows through the guide channel, the air distribution on the outer circle of the guide channel becomes denser. Furthermore, under the action of the guide groove, the air is compressed towards the inner circle of the guide channel as it flows out of the guide channel, thus allowing the air to mix more evenly with the fuel gas when it enters the fuel-air mixing device.

[0011] Preferably, the air filter is located above the oil-air mixing device, the air outlet of the air filter is located at the bottom of the air filter, and the air intake pipe is located directly below the air filter. This arrangement allows the air filter, air intake pipe, and oil-air mixing device to be vertically distributed, resulting in a compact structure for the entire intake system and facilitating installation and use.

[0012] This utility model has the following beneficial effects:

[0013] The intake system of this invention allows air to exit from the air filter and then enter the air-fuel mixture through the intake pipe. This allows the air to mix better and more evenly with the fuel gas when it enters the air-fuel mixture, thereby improving the uniformity of the air-fuel mixture. This, in turn, helps to increase the engine's output power and improve engine exhaust emissions. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of an embodiment of the intake system of a general-purpose engine according to the present invention;

[0015] Figure 2 for Figure 1 Top view of the central air intake duct;

[0016] Figure 3 for Figure 2 Sectional view of AA. Detailed Implementation

[0017] As those skilled in the art know, the flow cross section refers to the cross section perpendicular to the direction of liquid flow.

[0018] As those skilled in the art know, the outer circumference of the guide channel is the side with a larger bending radius, and the inner circumference of the guide channel is the side with a smaller bending radius.

[0019] As those skilled in the art know, a lumen refers to the internal cavity of an air intake pipe.

[0020] The depth of the guide groove refers to the distance measured vertically from the opening of the guide groove to the bottom of the groove.

[0021] The following detailed description illustrates the specific implementation method:

[0022] The reference numerals in the accompanying drawings include: air filter 1, intake pipe 2, oil-air mixing device 3, intake channel 21, exhaust end 211, center line 20, guide channel 22, intake end 220, inner circle side 221, outer circle side 222, guide groove 23, starting end 231, and ending end 232.

[0023] For ease of description, in this embodiment, double-dotted lines are used to frame and mark the air intake channel, the air guide channel, and the guide groove, respectively.

[0024] The basic implementation examples are as follows: Figure 1 , Figure 2 and Figure 3 The diagram illustrates an intake system for a general-purpose engine, comprising an air filter 1 and an air-fuel mixing device 3. An intake pipe 2 connects the outlet of the air filter 1 to the inlet of the air-fuel mixing device 3. In this embodiment, the air filter 1 is located above the air-fuel mixing device 3, the outlet of the air filter 1 is located at the bottom of the air filter 1, and the intake pipe 2 is located directly below the air filter 1. Preferably, the outlet of the air filter 1 is located at the bottom of the air filter 1 and is vertically downward. The inlet of the air-fuel mixing device 3 extends horizontally.

[0025] In this embodiment, an intake channel 21 and a guide channel 22 are sequentially arranged inside the intake duct 2 along the airflow path. The flow cross-section of the intake channel 21 gradually decreases along the airflow path. The position where the intake channel 21 connects to the air filter 1 is eccentrically located at the end where the intake duct 2 connects to the air filter 1. The exhaust end 211 of the intake channel 21 is eccentrically located relative to the end where the intake duct 2 connects to the air filter 1, and the positions of the exhaust end 211 of the intake channel 21 and the air filter 1 connecting the intake channel 21 are located on both sides of the centerline 20 of the end where the intake duct 2 connects to the air filter 1. Specifically, as shown... Figure 3As shown, the intake passage 21 is located on the right side of the upper end of the intake pipe 2, where it connects with the air filter 1. The exhaust end 211 of the intake passage 21 is offset to the left relative to the end of the intake pipe 2 connected with the air filter 1, so that the exhaust end 211 of the intake passage 21 connects with the air filter 1 and the intake passage 21 is located on both sides of the center line 20 of the end of the intake pipe 2 connected with the air filter 1.

[0026] The guide channel 22 is curved, with its inlet end 220 smoothly transitioning to the exhaust end 211 of the intake channel 21. The exhaust direction of the guide channel 22 faces the centerline 20 of the end of the intake pipe 2 connected to the air filter 1, and the outlet end of the guide channel 22 is positioned directly opposite the inlet of the oil-air mixing device 3. In this embodiment, the guide channel 22 is curved at 90°, thereby changing the vertical flow of airflow to a horizontal flow. A guide groove 23 extending along the airflow path is provided on the outer circumference 222 of the guide channel 22, and the end 232 of the guide groove 23 gradually extends towards the inner circumference 221 of the guide channel 22. In this embodiment, the starting end 231 of the guide groove 23 is tangential to the sidewall of the intake channel 21. The depth of the guide groove 23 gradually increases and then gradually decreases from the starting end 231 to the end 232.

[0027] Figure 3 The dashed arrows indicate the airflow path. In operation, air exits from the air filter 1 and enters the intake passage 21 vertically. It then enters the guide passage 22 from the lower end of the intake passage 21, and finally enters the air-fuel mixture 3 from the guide passage 22, achieving air-fuel mixture. Using this design, as air flows through the intake pipe 2, the acceleration effect of the intake passage 21 and the guiding effect of the guide passage 22 result in a more uniform mixture of air and fuel when it enters the air-fuel mixture 3. This improved air-fuel mixture uniformity contributes to increased engine output power and reduced engine emissions.

[0028] The above description is merely an embodiment of this utility model, and common knowledge such as specific structures and characteristics of the solution is not described in detail here. It should be noted that those skilled in the art can make several modifications and improvements without departing from the structure of this utility model, and these should also be considered within the protection scope of this utility model. These modifications and improvements will not affect the effectiveness of the implementation of this utility model or the practicality of the patent.

Claims

1. An intake system for a general-purpose engine, comprising an air filter and an air-fuel mixing device, wherein an intake duct is connected between the outlet of the air filter and the inlet of the air-fuel mixing device, and an intake passage and a guide passage are sequentially arranged inside the intake duct along the airflow path, characterized in that: The flow guide channel is curved, and the air inlet end of the flow guide channel is smoothly transitioned to the air outlet end of the air inlet channel. The air outlet end of the flow guide channel is set directly opposite the air inlet of the oil-gas mixing device. A guide groove extending along the airflow path is provided on the outer circle side of the flow guide channel, and the end of the guide groove gradually extends toward the inner circle side of the flow guide channel.

2. The intake system of a general-purpose engine according to claim 1, characterized in that: The starting end of the guide groove is tangential to the side wall of the air intake channel.

3. The intake system of a general-purpose engine according to claim 2, characterized in that: The depth of the guide groove is set to gradually increase and then gradually decrease from the starting end to the end.

4. The intake system of a general-purpose engine according to claim 3, characterized in that: The air intake channel has a flow cross-section that gradually decreases along the airflow path. The air intake channel is eccentrically positioned at the end where the air intake pipe connects to the air filter. The exhaust end of the air intake channel is eccentrically positioned relative to the end where the air intake pipe connects to the air filter. The exhaust end of the air intake channel and the air filter are located on opposite sides of the centerline of the end where the air intake pipe connects to the air filter. The exhaust direction of the guide channel is directed toward the centerline of the end where the air intake pipe connects to the air filter.

5. The intake system of a general-purpose engine according to claim 4, characterized in that: The air filter is located above the oil-gas mixing device, the air outlet of the air filter is located at the bottom of the air filter, and the air inlet pipe is located directly below the air filter.

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