An intake manifold for a two-cylinder engine

Abstract

The utility model relates to the technical field of double -cylinder engine air intake system discloses a double -cylinder engine's air intake manifold, including air inlet end and air outlet end, its characterized in that, the inner chamber of air intake manifold is provided with the partition structure, the partition structure divides air outlet end and separates first airflow channel and second airflow channel with the same gas flow basically and independent. The volume of air intake manifold is small and the combustion efficiency of double -cylinder engine is high, and the vibration of engine is small, and operation is more smooth.

Description

Technical Field

[0001] This utility model relates to the technical field of intake systems for twin-cylinder engines, and specifically to an intake manifold for a twin-cylinder engine. Background Technology

[0002] As a core component of the intake system, the engine intake manifold's core function lies in achieving the rational distribution and dynamic adjustment of airflow to each cylinder through precise structural design and optimized intake manifold dynamics in twin-cylinder engines. This function directly affects the engine's combustion efficiency, power output stability, and emission control level. With increasingly stringent global emission regulations (such as China VI and Euro VI standards) and the advancement of the "dual-carbon" strategy, the development of the intake manifold has become a key technological direction for improving engine combustion efficiency and reducing pollutant emissions in twin-cylinder engines.

[0003] Chinese patent document CN219932317U discloses an intake manifold for a twin-cylinder air-cooled engine, including an intake manifold, a left intake branch pipe, and a right intake branch pipe. The left and right intake branch pipes are provided on both sides of the intake manifold and communicate with it. An air filter flange is installed on the intake manifold. An intake flange is provided at the end of the left and right intake branch pipes away from the intake manifold. An arc-shaped diversion protrusion is provided on the inner wall of the intake manifold, and the arc-shaped diversion protrusion is arranged opposite to the air filter flange.

[0004] Existing twin-cylinder engines are prone to air competition between the two cylinders. When the intake volume and airflow characteristics (turbulence) of each cylinder are inconsistent, the formation of the air-fuel mixture and the combustion efficiency will differ, resulting in differences in power output per cylinder. This causes fluctuations in the overall power output of the engine and affects combustion efficiency; moreover, uneven power output between the two cylinders amplifies torque fluctuations in the crankshaft and flywheel, causing abnormal vibrations. Summary of the Invention

[0005] To solve the above-mentioned technical problems, this utility model provides an intake manifold for a two-cylinder engine, including an intake inlet end and an intake outlet end. The inner cavity of the intake manifold is provided with a partition structure, which divides the intake outlet end into a first airflow channel and a second airflow channel with basically the same and independent gas flow rate.

[0006] Furthermore, the separation structure includes a separating tongue, the base of which is located at the air intake outlet end, and the tip of which faces the air intake inlet end.

[0007] To reduce turbulent kinetic energy, the average radius of curvature of the separator tongue is ≥1.5 times the diameter of the intake manifold, satisfying a turbulent kinetic energy ≤30 m² / s. 2 Turbulent kinetic energy is the average of the mean square values ​​of the velocity fluctuation components in the three directions of a fluid element, and its mathematical expression is:

[0008] .

[0009] Preferably, the tip of the separating tongue extends to the air inlet end.

[0010] Furthermore, the separation structure also includes an airflow guide that extends from the air inlet end to the air outlet end and connects to the tip of the separation tongue.

[0011] Preferably, the airflow guide includes an upper guide and a lower guide, with a gas channel between the upper guide and the lower guide.

[0012] Preferably, the airflow guide extends gradually toward the air inlet / outlet end at an involute angle of 3°-8°.

[0013] To reduce the resonant frequency, the length of the airflow guide is ≥50mm, satisfying 30Hz ≤ resonant frequency ≤ 600Hz. The formula for the resonant frequency is:

[0014] Equivalent length Leq—length of the airflow guide, resonant frequency fres decreases, c—speed of sound, A—cross-sectional area, and V—volume.

[0015] Preferably, the first airflow channel is located on one side near the air inlet end, and the other side is the second airflow channel; the airflow path of the second airflow channel is longer than the airflow path of the first airflow channel.

[0016] Preferably, the air inlet and outlet ends of the first airflow channel and the second airflow channel are directly opposite the inlet of the oil-gas mixing device, and a common flange is provided at the air inlet and outlet ends.

[0017] This utility model has the following beneficial effects:

[0018] 1. This utility model divides the intake and outlet ends into two independent airflow channels with basically the same gas through a partition structure, which effectively avoids the phenomenon of air fighting between two cylinders, and at the same time ensures the uniformity of the flow coefficient and swirl ratio of each cylinder, making the engine run more stably. In addition, the integrated intake manifold design avoids the volume redundancy of traditional branch pipes, which meets the requirements of engine lightweighting and miniaturization.

[0019] 2. The separation structure adopts a large radius of curvature (≥1.5 times the pipe diameter) and an involute angle (3°-8°) design, smoothly guiding the airflow bifurcation, suppressing turbulent separation and energy dissipation, significantly reducing intake resistance, improving charging efficiency, and making the engine power response more sensitive, while reducing flow noise. Uniform combustion reduces local high-temperature areas and suppresses NOx formation; at the same time, it reduces the emission of unburned HC (hydrocarbons). Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the intake manifold of the twin-cylinder engine of this utility model, embodiment 1;

[0021] Figure 2 for Figure 1 Perspective view;

[0022] Figure 3 This is a schematic diagram of the intake manifold of the twin-cylinder engine of this utility model, embodiment 2;

[0023] Figure 4 for Figure 3 Side view. Detailed Implementation

[0024] The following detailed description illustrates the specific implementation method:

[0025] In this invention, the gas flow rates are basically the same: the gas flow rates through the first airflow channel and the second airflow channel differ by less than 5%.

[0026] Those skilled in the art will understand that turbulent kinetic energy (k) is defined as the average of the mean square values ​​of the velocity fluctuation components in the three directions of a fluid element, and its mathematical expression is:

[0027]

[0028] μ, υ, ω: Fluctuation components of fluid velocity in the three directions (x, y, z) of the Cartesian coordinate system (the deviation between instantaneous velocity and average velocity).

[0029] The formula for resonant frequency is:

[0030] Equivalent length Leq—length of the airflow guide, resonant frequency fres decreases, c—speed of sound, A—cross-sectional area, and V—volume represent what?

[0031] The average radius of curvature of the separator tongue in this invention is preferably 1.6 times the diameter of the intake manifold. The average radius of curvature of the separator tongue is obtained through dynamic analysis and fitting of experimental data.

[0032] The airflow guide is preferably extended towards the air inlet end at a gradually opening angle of 5°. The gradually opening angle of the airflow guide is obtained through dynamic analysis and fitting of experimental data.

[0033] The length of the airflow guide is preferably 60 mm, which is obtained through dynamic analysis and fitting of experimental data.

[0034] The reference numerals in the accompanying drawings include: 1. Inlet end; 2. Outlet end; 3. Main intake pipe; 4. First airflow channel; 5. Second airflow channel; 6. Separator tongue; 7. Airflow guide; 7. Upper guide; 701; Lower guide; 702; Gas channel; 8. Common flange; 9.

[0035] Example 1

[0036] like Figure 1 and 2 As shown, an intake manifold for a twin-cylinder engine includes an intake inlet end 1 and an intake outlet end 2. The inner cavity of the intake manifold 3 is provided with a partition structure, which divides the intake outlet end 2 into a first airflow channel 4 and a second airflow channel 5, which have essentially the same gas flow rate and are independent.

[0037] The separation structure includes a separating tongue 6, the root of which is located at the air inlet outlet end 2, and the tip of which faces the air inlet end 1.

[0038] The average radius of curvature of the separator tongue 6 is 1.5 times the diameter of the intake manifold 3. Turbulent kinetic energy (k) is defined as the average of the mean square values ​​of the velocity pulsation components in three directions of the fluid micro-particle, and its mathematical expression is:

[0039]

[0040] The turbulent kinetic energy is 23 m² / s. 2 .

[0041] The separation structure also includes an airflow guide 7, which extends from the air inlet end 1 to the air outlet end 2 and connects to the tip of the separator tongue 6.

[0042] The airflow guide 7 includes an upper guide 701 and a lower guide 702, and a gas channel 8 is formed between the upper guide 701 and the lower guide 702.

[0043] The airflow guide 7 extends gradually toward the air inlet / outlet end 2 at a gradually opening angle of 5°.

[0044] The length of the airflow guide 7 is 50mm, and the resonant frequency formula is:

[0045]

[0046] The resonant frequency is 270 Hz, the equivalent length Leq is the length of the airflow guide, the resonant frequency fres decreases, c is the speed of sound, A is the cross-sectional area, and V is the volume.

[0047] The first airflow channel 4 is located on one side near the air inlet end 1, and the other side is the second airflow channel 5; the airflow path of the second airflow channel 5 is longer than the airflow path of the first airflow channel 4.

[0048] The air inlet and outlet ends 2 of the first airflow channel 4 and the second airflow channel 5 are directly opposite the inlet of the oil-gas mixing device, and a common flange 9 is provided at the air inlet and outlet ends 2.

[0049] This implementation uses experimental data and dynamic analysis to fit a general formula applicable to turbulent kinetic energy and resonant frequency.

[0050] Example 2

[0051] like Figure 3 and 4 As shown, an intake manifold for a twin-cylinder engine includes an intake inlet end 1 and an intake outlet end 2. The inner cavity of the intake manifold 3 is provided with a partition structure, which divides the intake outlet end 2 into a first airflow channel 4 and a second airflow channel 5, which have essentially the same gas flow rate and are independent.

[0052] The separation structure includes a separating tongue 6, the root of which is located at the air inlet outlet end 2, and the tip of which faces the air inlet end 1. The tip of the separating tongue 6 extends to the air inlet end 1.

[0053] The average radius of curvature of the separator tongue 6 is 1.5 times the diameter of the intake manifold 3, and the turbulent kinetic energy is 25 m² / s. 2 Turbulent kinetic energy (k) is defined as the average of the mean square values ​​of the velocity fluctuation components in the three directions of a fluid element, and its mathematical expression is:

[0054] .

[0055] The above descriptions are merely embodiments of this utility model. Commonly known structures and characteristics are not described in detail here. Those skilled in the art are aware of all common technical knowledge in the field prior to the application date or priority date, are knowledgeable of all existing technologies in that field, and possess the ability to apply conventional experimental methods prior to that date. Therefore, those skilled in the art can, based on the guidance provided in this application, improve and implement this solution in conjunction with their own capabilities. Typical known structures or methods should not be obstacles for those skilled in the art to implement this application. 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. These modifications and improvements should also be considered within the scope of protection of this utility model, and will not affect the effectiveness of the implementation of this utility model or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. An intake manifold for a two-cylinder engine, comprising an intake inlet end and an intake outlet end, characterized in that, The inner cavity of the intake manifold is provided with a partition structure, which divides the intake outlet end into a first airflow channel and a second airflow channel with basically the same gas flow rate and are independent.

2. The intake manifold of the twin-cylinder engine according to claim 1, characterized in that: The separation structure includes a separating tongue, the base of which is located at the air inlet outlet end and the tip of which faces the air inlet end.

3. The intake manifold for a two-cylinder engine according to claim 2, characterized in that: The average radius of curvature of the partition tongue is greater than 1.5 times the pipe diameter of the air intake manifold, satisfying the condition that the turbulent kinetic energy is less than or equal to 30 m2 / s 2 , wherein the turbulent kinetic energy is the average value of the square root of the fluctuation components of the three-direction velocity of the fluid micro-cluster, and the formula is: .

4. The intake manifold for a two-cylinder engine according to claim 3, characterized in that: The tip of the separating tongue extends to the air inlet end.

5. The intake manifold for a two-cylinder engine of claim 3, characterized in that: The separation structure also includes an airflow guide that extends from the air inlet end to the air outlet end and connects to the tip of the separation tongue.

6. The intake manifold for a two-cylinder engine according to claim 5, characterized in that: The airflow guide includes an upper guide and a lower guide, with a gas channel between the upper guide and the lower guide.

7. An intake manifold for a two-cylinder engine according to claim 6, characterized in that: The airflow guide extends gradually toward the air inlet / outlet end at an involute angle of 3°-8°.

8. An intake manifold for a two-cylinder engine according to claim 7, characterized in that: The length of the airflow guide is ≥50mm, and it satisfies the condition 30Hz≤resonant frequency≤600Hz. The formula for the resonant frequency is: equivalent length —Length of airflow guide, resonant frequency Decrease, c—velocity of sound, A—cross-sectional area, and V—volume.

9. An intake manifold for a two-cylinder engine according to claim 8, characterized in that: The first airflow channel is located on one side near the air inlet, and the other side is the second airflow channel; the airflow path of the second airflow channel is longer than that of the first airflow channel.

10. The intake manifold for a two-cylinder engine of claim 9, characterized in that: The inlet and outlet ends of the first and second airflow channels are directly opposite the inlet of the oil-gas mixing device, and a common flange is provided at the inlet and outlet ends.

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