Gas inlet structure of natural gas engine

Abstract

The utility model discloses a natural gas engine air inlet structure which comprises an air inlet pipeline, an air inlet connecting pipe and a cylinder cover, the air inlet pipeline is communicated with a cavity of the cylinder cover through the air inlet connecting pipe, and a bent section used for changing the direction of air flow entering the cylinder cover is arranged at the connecting end, close to the cylinder cover, of the air inlet connecting pipe. The natural gas engine air inlet structure is reasonable in design, the end, close to the cylinder cover, of the air inlet connecting pipe is bent, air inlet flow cannot impact a certain cylinder, the air inlet flow of each cylinder of the engine is uniform, temperature and humidity uniformity of air entering each cylinder is achieved, acting of each cylinder of the engine is more uniform, the problem that one cylinder of the engine is on fire is solved, and the service life of the engine is prolonged. And meanwhile, the reliable and durable service life of the engine combustion chamber is prolonged.

Description

Technical Field

[0001] The utility model relates to the technical field of natural gas engines, in particular to an intake structure of a natural gas engine. Background Technique

[0002] There is a phenomenon of frequent misfires in a certain cylinder at the edge of a natural gas engine in the market (as shown in Figure 6 ). After the engine is returned to the factory for testing, the engine runs normally without any hardware faults. Through problem decomposition and CAE calculation and analysis, it is understood that the real cause of the misfire is that the intake pipe is arranged directly opposite a certain cylinder at the edge of the engine, and the air flow is easy to directly impact a certain cylinder at the edge, resulting in uneven water content distribution in each cylinder and uneven EGR distribution in each cylinder; the highest water content ratio in a certain cylinder at the edge reaches 41.7%, and the actual EGR is too high, causing abnormal combustion and misfires.

[0003] For example, an intake system of a natural gas engine disclosed in Patent CN210152810U includes an intake pressure stabilizing chamber and an intake manifold connected between the intake pressure stabilizing chamber and the intake ports of each cylinder. The ratio of the sum of the volume of the intake pressure stabilizing chamber and the volume of the intake manifold to the engine displacement is between 0.8 - 1.0; the end of the intake elbow is directly corresponding to a cylinder, and the intake air flow directly impacts a certain cylinder, which is likely to cause problems such as abnormal combustion and misfires. Content of the Utility Model

[0004] Aiming at the deficiencies of the prior art, the utility model provides an intake structure of a natural gas engine to achieve the purpose of uniform intake air flow in each cylinder of the engine and not being prone to abnormalities.

[0005] In order to solve the above technical problems, the technical solution adopted by the utility model is as follows:

[0006] The intake structure of the natural gas engine includes an intake pipeline, an intake pipe and a cylinder head. The intake pipeline is connected to the cavity of the cylinder head through the intake pipe, and a bending section for changing the air flow direction entering the cylinder head is provided at the connection end of the intake pipe close to the cylinder head.

[0007] Further:

[0008] The intake pipe sequentially has a butt end, a front section of the pipe, a bent section of the pipe, a rear section of the pipe and a connection end to the cylinder head according to the air flow direction.

[0009] Both the butt end and the connection end to the cylinder head are flange structures, and their axes are perpendicularly arranged.

[0010] Both the front section of the pipe and the rear section of the pipe are bent sections.

[0011] The angle of the bending section is less than 90 degrees.

[0012] The curvature of the bent section is greater than that of the rear section of the intake pipe.

[0013] The curvature of the rear section of the intake pipe is greater than that of the front section of the intake pipe.

[0014] Compared with the prior art, the present utility model has the following advantages:

[0015] The intake structure of the natural gas engine is reasonably designed. The end of the intake pipe near the cylinder head is bent, so that the intake air flow will not impact a certain cylinder, making the intake air flow of each cylinder of the engine uniform. Thus, the temperature and humidity uniformity of the air entering each cylinder is achieved, and the work done by each cylinder of the engine is more uniform. It not only solves the problem of misfire of a certain cylinder of the engine, but also improves the reliable durability life of the combustion chamber of the engine. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The following briefly describes the content expressed by each drawing of this specification and the marks in the drawings:

[0017] Figure 1 It is a schematic diagram of the intake pipe structure of the present utility model.

[0018] Figure 2 It is a schematic diagram of the intake of the present utility model.

[0019] Figure 3 It is a schematic diagram for comparing the intake flow coefficient between the present utility model and the prior art.

[0020] Figure 4 It is a schematic diagram for comparing the intake humidity between the present utility model and the prior art.

[0021] Figure 5 It is a schematic diagram of the calibration strategy of the present utility model.

[0022] Figure 6 It is a schematic diagram of the prior intake.

[0023] In the figure:

[0024] 1. Docking end, 2. Front section of the intake pipe, 3. Bent section of the intake pipe, 4. Rear section of the intake pipe, 5. Cylinder head connection end. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] The following further elaborates on the specific embodiments of the present utility model by describing the embodiments with reference to the drawings.

[0026] As Figures 1 to 5 shown, the intake structure of the natural gas engine includes an intake pipeline, an intake pipe, and a cylinder head. The intake pipeline is connected to the cavity of the cylinder head through the intake pipe; a bent section for changing the direction of the air flow entering the cylinder head is provided at the connection end of the intake pipe near the cylinder head.

[0027] AsFigure 2 As shown, the connection between the intake pipe and the cylinder head is arranged corresponding to the side cylinder. The bent section near the cylinder head makes the intake air flow in obliquely, so that the intake air flow does not impact a certain cylinder, making the intake air flow of each cylinder of the engine uniform, thus achieving the uniformity of the temperature and humidity of the air entering each cylinder, making the work of each cylinder of the engine more uniform, not only solving the problem of misfire of a certain cylinder of the engine, but also improving the reliable durability life of the engine combustion chamber.

[0028] The intake pipe successively has a butt end 1, a front pipe section 2, a pipe bent section 3, a rear pipe section 4 and a cylinder head connection end 5 in the air flow direction; it is butted with the intake pipeline through the butt end and is butted with the cylinder head through the cylinder head connection end;

[0029] Furthermore, both the butt end and the cylinder head connection end are flange structures, which are convenient for connection; and their axes are perpendicular to each other, with a compact structure and relatively small occupied space.

[0030] Both the front pipe section and the rear pipe section are bent sections; the angle of the pipe bent section is less than 90 degrees. The curvature of the pipe bent section is greater than that of the rear pipe section, and the curvature of the rear pipe section is greater than that of the front pipe section. On the premise of not changing the overall layout of the engine, the intake uniformity is achieved by changing the structure of the intake pipe, and then cooperating with a new calibration strategy.

[0031] The utility model solves the engine misfire problem by changing the structure of the intake pipe, changing the intake swirl ratio and the flow coefficient, and then cooperating with calibration to expand the misfire boundary; and makes the intake swirl ratio and the flow coefficient change. Through the change of the swirl ratio, the intake air volume and the temperature and humidity change of each cylinder of the engine are more uniform; through performance verification, changing the structure of the intake pipe does not cause performance deterioration; finally, the misfire boundary of the engine is expanded through calibration, and the safe working range of the engine is enlarged.

[0032] The above is only a description of the preferred embodiments of the utility model, and the above technical features can be arbitrarily combined to form multiple embodiment schemes of the utility model.

[0033] The above has made an exemplary description of the utility model in conjunction with the drawings. Obviously, the specific implementation of the utility model is not limited by the above methods. As long as various non-substantive improvements are made by adopting the concept and technical scheme of the utility model, or the concept and technical scheme of the utility model are directly applied to other occasions without improvement, they are all within the protection scope of the utility model.

Claims

1. An intake structure for a natural gas engine, comprising an intake pipeline, an intake connection pipe and a cylinder head, wherein the intake pipeline is connected to the cavity of the cylinder head through the intake connection pipe, and is characterized in that: The connecting end of the intake pipe close to the cylinder head is provided with a bending section for changing the flow direction of the air entering the cylinder head.

2. The intake structure of the natural gas engine according to claim 1, wherein: The intake pipe successively has a butt joint end, a front pipe section, a pipe bending section, a rear pipe section and a cylinder head connection end according to the air flow direction.

3. The intake structure of the natural gas engine according to claim 2, wherein: Both the butt joint end and the cylinder head connection end are flange structures, and their axes are perpendicularly arranged.

4. The intake structure of the natural gas engine according to claim 2, wherein: Both the front pipe section and the rear pipe section are bending sections.

5. The intake structure of the natural gas engine according to claim 4, wherein: The angle of the bending section is less than 90 degrees.

6. The intake structure of the natural gas engine according to claim 4, wherein: The curvature of the bending section is greater than that of the rear pipe section.

7. The intake structure of the natural gas engine according to claim 6, wherein: The curvature of the rear pipe section is greater than that of the front pipe section.

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