阅读说明：本技术 柴油机直流扫气结构及柴油机 (Diesel engine direct current scavenging structure and diesel engine ) 是由 崔磊 桂勇 李磊 于 2019-10-30 设计创作，主要内容包括：本发明公开了一种柴油机直流扫气结构,属于柴油机技术领域。该种扫气结构包括气缸,所述气缸的下端设有扫气口,所述扫气口有若干个,并沿所述气缸外壁周向分布,每一所述扫气口均包括上部扫气口和下部扫气口,所述上部扫气口和所述下部扫气口均为沿所述气缸外壁轴向延伸的长条形孔,在水平正投影方向上,所述上部扫气口的中心轴线与所述上部扫气口的中心到所述气缸中心连线的夹角为α；所述下部扫气口的中心轴线与所述下部扫气口横截面的中心到所述气缸横截面中心连线的夹角为β,且β<α。本发明的结构使涡流中心附近的燃烧废气与新鲜空气不易混合,使扫气效率提高。(The invention discloses a direct-current scavenging structure of a diesel engine, and belongs to the technical field of diesel engines. The scavenging structure comprises a cylinder, wherein the lower end of the cylinder is provided with a plurality of scavenging ports which are distributed along the circumferential direction of the outer wall of the cylinder, each scavenging port comprises an upper scavenging port and a lower scavenging port, the upper scavenging port and the lower scavenging port are strip-shaped holes which extend along the axial direction of the outer wall of the cylinder, and in the horizontal orthographic projection direction, the included angle between the central axis of the upper scavenging port and the connecting line from the center of the upper scavenging port to the center of the cylinder is alpha; the included angle between the central axis of the lower scavenging port and the connecting line between the center of the cross section of the lower scavenging port and the center of the cross section of the cylinder is beta, and beta is less than alpha. The structure of the invention ensures that the combustion waste gas near the center of the vortex is not easy to mix with the fresh air, thus improving the scavenging efficiency.)

1. The direct-flow scavenging structure of the diesel engine is characterized by comprising a cylinder (1), wherein scavenging ports (100) are arranged at the lower end of the cylinder (1), the scavenging ports (100) are distributed along the circumferential direction of the outer wall of the cylinder (1), each scavenging port (100) comprises an upper scavenging port (101) and a lower scavenging port (102), the upper scavenging port (101) and the lower scavenging port (102) are strip-shaped holes axially extending along the outer wall of the cylinder (1), and in the horizontal orthographic projection direction, the included angle between the central axis of the upper scavenging port (101) and the connecting line between the center of the upper scavenging port (101) and the center of the cylinder (1) is alpha; the included angle between the central axis of the lower scavenging port (102) and the connecting line between the center of the cross section of the lower scavenging port (102) and the center of the cross section of the cylinder (1) is beta, and beta is less than alpha.

2. The diesel once-through scavenging structure according to claim 1, characterized in that the top level of the upper scavenging port (101) is flush and the bottom level of the lower scavenging port (102) is flush.

3. The diesel engine straight-flow scavenging structure according to claim 2, wherein the top of the upper scavenging port (101) and the bottom of the lower scavenging port (102) are both arc-shaped, and the connection part of the upper scavenging port (101) and the lower scavenging port (102) is in arc-shaped smooth transition.

4. The diesel engine uniflow scavenging structure according to claim 1, characterized in that an exhaust valve is provided on a cylinder (1) cover at the top of the cylinder (1).

5. The diesel uniflow scavenging structure according to claim 4, further comprising a cam configured to drive the exhaust valve to open and close.

6. The diesel uniflow scavenging structure according to claim 4, further comprising a hydraulic system configured to drive the exhaust valve to open and close.

7. The diesel engine straight-flow scavenging structure according to claim 1, wherein the inner walls of the upper scavenging port (101) and the lower scavenging port (102) are tooth-shaped.

8. A diesel engine characterized by comprising the diesel once-through scavenging structure according to any one of claims 1 to 7.

Technical Field

The invention relates to the technical field of diesel engines, in particular to a direct-current scavenging structure of a diesel engine and the diesel engine applying the same.

Background

The scavenging process of the two-stroke diesel engine covers the whole stage from the opening of a scavenging port to the closing of an exhaust valve, in the stage, the engine needs to discharge the combustion waste gas in the previous cycle out of a cylinder, also needs to suck enough fresh air for the next cycle, and simultaneously needs the scavenging port to form a vortex with certain intensity, so that the oil-gas mixing is promoted and the later-period sufficient combustion is ensured. Therefore, the scavenging process is an essential component in the working process of the engine and is a key link for determining various performances of the engine. The scavenging mode is divided into three modes of bend flow scavenging, cross flow scavenging and direct flow scavenging. Compared with other two modes, the direct-flow scavenging has the advantage of high scavenging efficiency, and the direct-flow scavenging mode can be divided into two types: port-valve type and port-air port type.

The scavenging port in the form of a port-valve is located at the lower end of the cylinder, uniformly surrounds the cylinder in a ring shape, and is opened and closed under the control of the reciprocating motion of the piston, and the exhaust valve is located at the top of the cylinder and is opened and closed under the drive of a cam mechanism or an electric signal. In the working process of the engine, after fuel in a cylinder burns, a piston is pushed to move towards a bottom dead center, at the moment, an exhaust valve and a scavenging port are sequentially opened, airflow enters a cylinder through the scavenging port, a scavenging vortex is formed in the cylinder due to a certain angle formed between the scavenging port and the axis of the cylinder, and the scavenging vortex pushes combustion exhaust gas in the cylinder of the previous cycle to be discharged out of the cylinder through the exhaust valve. In this process, the discharge degree of the combustion exhaust gas is directly related to the scavenging quality, and although the uniflow scavenging has a good scavenging effect, the scavenging vortex formed by the scavenging port is a typical binary vortex, and the pressure in the vortex core area is low, so that the combustion exhaust gas is easily mixed with the fresh air, and the scavenging quality is deteriorated.

Therefore, it is desirable to provide a direct-flow scavenging structure for a diesel engine and a diesel engine, so as to solve the technical problem of poor scavenging quality caused by the low pressure of the scroll area.

Disclosure of Invention

The invention aims to provide a direct-current scavenging structure of a diesel engine and the diesel engine, which can reasonably improve the structure of scavenging vortex, increase the pressure intensity of a vortex core area and increase the speed of the vortex core, thereby improving the scavenging quality.

In order to realize the purpose, the following technical scheme is provided:

the invention provides a direct-current scavenging structure of a diesel engine, which comprises a cylinder, wherein the lower end of the cylinder is provided with a plurality of scavenging ports, the scavenging ports are distributed along the circumferential direction of the outer wall of the cylinder, each scavenging port comprises an upper scavenging port and a lower scavenging port, the upper scavenging port and the lower scavenging port are strip-shaped holes axially extending along the outer wall of the cylinder, and in the horizontal orthographic projection direction, the included angle between the central axis of the upper scavenging port and the connecting line between the center of the upper scavenging port and the center of the cylinder is alpha; the included angle between the central axis of the lower scavenging port and the connecting line between the center of the cross section of the lower scavenging port and the center of the cross section of the cylinder is beta, and beta is less than alpha.

Further, the top height of the upper scavenging port is flush, and the bottom height of the lower scavenging port is flush.

Furthermore, the top of the upper scavenging port and the bottom of the lower scavenging port are both arc-shaped, and the connecting part of the upper scavenging port and the lower scavenging port is in arc-shaped smooth transition.

Further, an exhaust valve is arranged on a cylinder cover at the top of the cylinder.

Further, the diesel once-through scavenging structure further comprises a cam configured to drive the exhaust valve to open and close. Further, the diesel uniflow scavenging structure further comprises a hydraulic system configured to drive the exhaust valve to open and close.

Furthermore, the inner walls of the upper scavenging port and the lower scavenging port are in a tooth shape.

The invention also provides a diesel engine, which comprises the diesel engine direct-flow scavenging structure in any technical scheme.

Compared with the prior art, the direct-current scavenging structure of the diesel engine provided by the invention is designed with the upper scavenging port and the lower scavenging port, the numerical values of the included angle alpha and the included angle beta are different, and the numerical value of the included angle alpha is larger than that of the included angle beta. Because the included angle alpha is larger than the included angle beta, the strength of the vortex c is higher than that of the vortex d, the central pressure of the vortex d is higher than that of the vortex c, and after the vortex d and the vortex c are converged, the central pressure of the total vortex is higher than that of the vortex d (namely the included angle alpha of the scavenging port is equal to the included angle beta in the prior art).

Drawings

FIG. 1 is a schematic diagram of a uniflow scavenging structure of a diesel engine according to an embodiment of the present invention;

FIG. 2 is a front view of a uniflow scavenging structure of a diesel engine in the embodiment of the invention;

FIG. 3 is a cross-sectional view taken along A-A of FIG. 2;

fig. 4 is a sectional view taken along the direction B-B in fig. 2.

Reference numerals:

1-a cylinder; 100-scavenging port; 101-upper scavenging port; 102-lower scavenging port.

Detailed Description

In order to make the technical problems solved, technical solutions adopted and technical effects achieved by the present invention clearer, the technical solutions of the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

As shown in fig. 1-4, the present embodiment provides a direct-flow scavenging structure for a diesel engine, which includes a cylinder 1, where the lower end of the cylinder 1 is provided with a plurality of scavenging ports 100, each scavenging port 100 includes an upper scavenging port 101 and a lower scavenging port 102, the upper scavenging port 101 and the lower scavenging port 102 are strip-shaped holes extending axially along the outer wall of the cylinder 1, and in a horizontal orthogonal projection direction, an included angle α is formed between a central axis of the upper scavenging port 101 and a line connecting the center of the upper scavenging port 101 to the center of the cylinder 1; the included angle between the central axis of the lower scavenging port 102 and the connecting line between the center of the cross section of the lower scavenging port 102 and the center of the cross section of the cylinder 1 is beta, and beta < alpha.

When the direct-flow scavenging structure of the diesel engine of the embodiment is used in the diesel engine, intake air flows into the cylinder 1 through the scavenging port 100 to form a vortex, flows through the upper scavenging port 101 to form a vortex c in the cylinder 1, and flows through the lower scavenging port 102 to form a vortex d. Because the included angle alpha is larger than the included angle beta, the strength of the vortex c is higher than that of the vortex d, the central pressure of the vortex d is higher than that of the vortex c, and after the vortex d and the vortex c are converged, the central pressure of the total vortex is higher than that of the vortex d (namely the included angle alpha of the scavenging port 100 is equal to the included angle beta in the prior art).

For successful scavenging, an exhaust valve is provided in the cylinder 1 head at the top of the cylinder 1. Specifically, a cam may be provided on the diesel engine dc scavenging structure to drive the exhaust valve to open and close by the cam. It is of course also possible to provide a hydraulic system on the diesel engine, which hydraulic system is configured to drive the exhaust valve opening and closing.

Alternatively, as shown in fig. 2, the scavenging ports 100 of the present embodiment are uniformly distributed along the circumferential direction of the outer wall of the cylinder 1. The top of the upper scavenging port 101 and the bottom of the lower scavenging port 102 are both arc-shaped, the connecting part of the upper scavenging port 101 and the lower scavenging port 102 is arc-shaped smooth transition, and the arc-shaped structure is more favorable for driving the residual flue gas in the cylinder 1, thereby ensuring the ventilation quality. Secondly, the inner walls of the upper scavenging port 101 and the lower scavenging port 102 of the present embodiment are in the shape of tooth, which can separate the air flow to make the air flow form a bundle, thereby reducing turbulence and making the scavenging more powerful and thorough.

The embodiment also provides a diesel engine which comprises the diesel engine direct-current scavenging structure. In the diesel engine of the present embodiment, the uniflow scavenging structure makes it difficult for the combustion exhaust gas near the center of the swirl to mix with the fresh air, and the scavenging quality is enhanced.

It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present invention and the technical principles employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.