Compact long-path stratified scavenging cylinder block

Abstract

The present invention discloses a compact long-path layered scavenging structure cylinder body, comprising a cylinder body, an intermediate side cover, and an outer side cover. A mixed gas scavenging passage is provided on the cylinder body, connecting the crankcase and the main scavenging port on the intermediate side cover; an intermediate main scavenging passage is provided on the outer side cover, and two auxiliary scavenging passages are provided on both sides, connecting the two auxiliary scavenging ports on the intermediate side cover, and the two auxiliary scavenging ports on the intermediate side cover are connected to the cylinder body scavenging passage. The effect is that the length of the entire scavenging path of the cylinder body can be lengthened while ensuring the compact structure of the gasoline engine, and the intake storage volume of pure air in the scavenging path is increased, which not only reduces the residual exhaust gas in the combustion chamber, reduces the escape of fresh mixed gas, and reduces emissions, but also reduces the proportion of pure air entering the crankcase during the intake process, prevents the mixed gas of the next cycle from being too lean, and improves the combustion effect.

Description

Technical Field

[0001] The invention relates to the technical field of two-stroke gasoline engines, in particular to a compact long-path stratified scavenging structure cylinder. Background Art

[0002] At present, the common low-emission two-stroke gasoline engine structures in the market are divided into two categories. One is the exhaust gas after-treatment structure, that is, a certain amount of catalyst is added to the muffler, and the exhaust gas is subjected to secondary combustion in the muffler to achieve the requirement of reducing emissions. Due to the high combustion temperature in the muffler, this structure makes the temperature of the entire gasoline engine high during operation, with low safety and poor comfort. In addition, as the cost of precious metals used in catalysts increases year by year, gasoline engine manufacturers have to gradually reduce the precious metal content of catalysts or change the formula, resulting in gasoline engine emissions getting closer and closer to the limit value. The other is the stratified scavenging structure, which has been widely used in various types of two-stroke gasoline engines, but is limited by the influence of engine power, mixture concentration, scavenging, scavenging structure, etc., so that traditional stratified scavenging gasoline engines, especially small-displacement stratified scavenging gasoline engines below 50cc, have to perform lean combustion, the engine durability and reliability are not high, and the original emissions are usually difficult to meet or easily exceed emission regulations.

[0003] Common small-displacement stratified scavenging gasoline engines have a small size and compact structure, so the scavenging path between the cylinder combustion chamber and the crankcase is shorter than that of large-displacement stratified scavenging gasoline engines. During the scavenging process, the storage amount of pure air in the scavenging path is insufficient, or the amount of mixed air with the next cycle is large, which reduces the scavenging quality. In addition, small-displacement gasoline engines have low power and are difficult to meet emission requirements. Therefore, it is urgent to develop a compact long-path stratified scavenging structure cylinder to improve the scavenging quality and reduce engine emissions. Summary of the invention

[0004] The present invention provides a compact long-path layered scavenging structure cylinder body. It comprises a cylinder body, an intermediate side cover, and an external side cover, and is characterized in that: a mixed gas scavenging passage is provided on the cylinder body, one end of the scavenging passage is provided on the cylinder body flange surface and communicates with the crankcase, and the other end is communicated with the main scavenging port provided on the intermediate side cover; an intermediate main scavenging passage is provided on the external side cover and communicates with the main scavenging port of the intermediate side cover; auxiliary scavenging passages are also designed on both sides of the intermediate main scavenging passage of the external side cover and communicate with the top end of the intermediate main scavenging passage, and the main and auxiliary scavenging passages are separated by retaining walls on both sides to ensure that the mixed gas flows upward after entering the intermediate main scavenging passage of the external side cover, is divided at the top thereof, and enters the auxiliary scavenging passages on both sides respectively; the lower parts of the auxiliary scavenging passages on both sides of the external side cover are communicated with the two auxiliary scavenging ports at the corresponding positions of the intermediate side cover, so that the mixed gas in the auxiliary scavenging passages on both sides of the external side cover enters the internal scavenging passages of the intermediate side cover, and finally enters the cylinder body through the cylinder body scavenging port. During scavenging, the mixed gas first passes upward from the crankcase through the scavenging passage on the cylinder body and the main scavenging port on the middle side cover to enter the middle main scavenging passage of the outer side cover, then is split at the end of the middle main scavenging passage, and then enters the two scavenging passages of the outer side cover in a circuitous manner downward, and then passes through the two scavenging ports on the middle side cover and enters the two internal scavenging passages composed of the cylinder body and the middle side cover upward for scavenging. Through the above scheme, the length of the entire scavenging path of the cylinder body can be lengthened under the premise of ensuring the compact structure of the gasoline engine. Thereafter, on the one hand, the intake storage amount of pure air in the scavenging path can be increased during the intake stroke, so that more pure air can participate in scavenging, further reducing the residual exhaust gas coefficient in the combustion chamber, reducing the amount of fresh mixed gas escaping, and reducing emissions; on the other hand, after the scavenging path is lengthened, the proportion of pure air entering the crankcase during the intake process can be reduced, preventing the mixed gas from being too lean in the next cycle, and improving combustion. The side cover and cylinder body have simple structures, can be realized by a mold, and no additional processing steps are required. The manufacturing cost is low, and it has good processability and practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Figure 1 This is a schematic diagram of the cylinder body and mixed gas flow of the layered scavenging structure of the present invention.

[0006] Figure 2 Schematic diagram of the cylinder air inlet direction of the present invention

[0007] Figure 3 This is a cross-sectional view of the cylinder body along the AA axis and a schematic diagram of the mixed gas flow direction of the present invention.

[0008] Figure 4 This is a cross-sectional view of the cylinder body along the BB axis and a schematic diagram of the mixed gas flow direction of the present invention.

[0009] Figure 5 The present invention is a cross-sectional view of the cylinder body CC and a schematic diagram of the mixed gas flow direction

[0010] Figure 6This is a cross-sectional view of the cylinder body in the DD direction and a schematic diagram of the mixed gas flow direction of the present invention.

[0011] Figure 7 EE-direction cross-sectional view of the cylinder body and mixed gas flow diagram of the present invention

[0012] Explanation of the numbers in the figure: 1, cylinder block; 2, left middle side cover; 3, right middle side cover; 4, left outer side cover; 5, right outer side cover; 6, crankcase; 1a, left scavenging passage of cylinder block; 1b, right scavenging passage of cylinder block; 2a, main scavenging port of left middle side cover; 3a, main scavenging port of right middle side cover; 2b, auxiliary scavenging port 1 of left middle side cover; 3b, auxiliary scavenging port 1 of right middle side cover; 2c, auxiliary scavenging port 2 of left middle side cover; 3c, right Second auxiliary scavenging port of the middle side cover; 2d, first internal scavenging duct on the left side; 3d, first internal scavenging duct on the right side; 2e, second internal scavenging duct on the left side; 3e, second internal scavenging duct on the right side; 4a, main scavenging duct on the outer side cover on the left side; 5a, main scavenging duct on the outer side cover on the right side; 4b, first auxiliary scavenging duct on the outer side cover on the left side; 5b, first auxiliary scavenging duct on the outer side cover on the right side; 4c, second auxiliary scavenging duct on the outer side cover on the left side; 5c, second auxiliary scavenging duct on the outer side cover on the right side; x, mixture. DETAILED DESCRIPTION

[0013] like Figure 2 As shown, a compact long-path stratified scavenging structure cylinder body includes a cylinder body 1, a left middle side cover 2, a right middle side cover 3, a left outer side cover 4, and a right outer side cover 5.

[0014] like Figure 4 As shown in the figure, during the operation of the gasoline engine, when the piston 7 moves downward, the compressed mixed gas x in the crankcase 6 passes through the cylinder scavenging passages 1a, 1b connected to the crankcase and the middle side cover main scavenging ports 2a, 3a respectively under the action of positive pressure, and then first enters the outer side cover main scavenging passages 4a, 5a. Figure 5 , Figure 6 As shown, the mixed gas x in the main scavenging passages 4a and 5a of the outer side cover is detoured and split at the top end of the main scavenging passages 4a and 5a and enters the auxiliary scavenging passages 4b and 4c and 5b and 5c on both sides of the outer side cover respectively, and then enters the two left inner scavenging passages 2d (2d) through the two auxiliary scavenging ports 2b and 2c of the left middle side cover and the two auxiliary scavenging ports 3b and 3c of the right middle side cover respectively. Figure 3 , Figure 7 shown), 2e ( Figure 3 as shown) and the two internal scavenging ducts 3d on the right side ( Figure 3 , Figure 7 shown), 3e ( Figure 3 As shown in the figure, it finally enters the cylinder combustion chamber for scavenging.

[0015] like Figure 1As shown, it is a complete exploded view of the scavenging path on the left side of the cylinder body of the compact long-path layered scavenging structure of the present invention.

[0016] It has been proven that the use of the circuitous, multi-directional stratified scavenging path of the present invention composed of an outer side cover and an intermediate side cover can, while ensuring the compactness of the engine structure, lengthen the scavenging path by nearly two times compared with the conventional structure, thereby increasing the scavenging path volume and thereby increasing the intake volume of pure air of the stratified scavenging gasoline engine, further reducing the emissions of the gasoline engine.

[0017] It has been proven that the use of the compact long-path stratified scavenging structure cylinder block of the present invention can reduce the proportion of pure air entering the crankcase during the intake process, prevent the fresh mixture concentration in the next cycle in the crankcase from being too thin, improve combustion, and ensure the lubrication of the moving parts in the crankcase.

[0018] The known ideal stratified scavenging ventilation effect is that the exhaust gas generated by the previous cycle of work in the cylinder combustion chamber is swept out by the pure air of the next cycle. When the ventilation process is completed, the exhaust gas generated by the previous cycle of work in the cylinder combustion chamber and the pure air of the next cycle have been discharged, and the cylinder combustion chamber is only filled with the fresh mixed gas of the next cycle, and the fresh mixed gas of the next cycle does not escape. It has been proven that, in combination with the existing operating speed, scavenging direction and scavenging timing of the gasoline engine, by adjusting the shape and structure of the external side cover and the middle side cover of the present invention, it is possible to match the length and shape of the scavenging path according to the needs of the cylinder ventilation, and to make the ventilation effect as close to the ideal stratified scavenging ventilation effect as possible, so as to reduce emissions and improve reliability.

[0019] It has been proven that the components such as the side cover and the cylinder body of the embodiment of the present invention have a simple structure, can be realized by a mold, do not need to increase the processing steps, have a low manufacturing cost, and have good processability and practicality.

[0020] Although the best structure and principle for implementing the present invention are introduced above, the present invention is not limited thereto. Without departing from the technical concept and purpose of the present invention, modifications made to the described implementation in terms of shape, size, and other detailed structures by technicians in this field are still included in the present invention.

Claims

1. A compact long-path stratified scavenging structure cylinder, comprising a cylinder, an intermediate side cover, and an outer side cover, characterized in that: A mixture scavenging passage is provided on the cylinder body, one end of the scavenging passage is arranged on the cylinder body flange surface and communicates with the crankcase, and the other end is communicated with the main scavenging port provided on the middle side cover; an middle main scavenging passage is provided on the outer side cover and communicates with the main scavenging port of the middle side cover; auxiliary scavenging passages are respectively designed on both sides of the middle main scavenging passage of the outer side cover and communicate with the top end of the middle main scavenging passage, and the main scavenging passage and the auxiliary scavenging passage are separated by retaining walls on both sides, and the mixture flows upward after entering the middle main scavenging passage of the outer side cover, is divided at its top, and respectively enters the auxiliary scavenging passages on both sides; the lower parts of the auxiliary scavenging passages on both sides of the outer side cover are communicated with the two auxiliary scavenging ports at the corresponding positions of the middle side cover, so that the mixture in the auxiliary scavenging passages on both sides of the outer side cover enters the internal scavenging passages of the middle side cover, and finally enters the cylinder body through the cylinder body scavenging port.

2. A compact long-path stratified scavenging structure cylinder according to claim 1, characterized in that: The middle side cover and the outer side cover are formed by stacking and assembling two or more side covers.

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