Air supply structure of motorcycle engine

Abstract

The present invention provides an air supply structure for a motorcycle engine, which belongs to the technical field of motorcycles. It solves the problem of direct leakage when performing secondary purification of exhaust gas in existing motorcycles. The air supply structure of the motorcycle engine comprises a cylinder head with an exhaust channel, and the air supply structure comprises an air supply channel opened on the cylinder head from top to bottom, the upper end of the air supply channel is connected to the outside, the lower end of the air supply channel is inclined toward the inner end of the exhaust channel, the lower end port of the air supply channel penetrates to the top wall of the exhaust channel, and the top wall of the exhaust channel has a downwardly protruding guide convex portion, the guide convex portion is located between the lower end port of the air supply channel and the inner end port of the exhaust channel and close to the edge of the lower end port of the air supply channel, and the guide convex portion is lower than the lower end port of the air supply channel. The air supply structure of the motorcycle engine can prevent the exhaust gas from being directly discharged from the air supply channel and causing exhaust gas leakage.

Description

Technical Field

[0001] The invention belongs to the technical field of motorcycles and relates to an air supply structure of a motorcycle engine. Background Art

[0002] The motorcycle engine includes a cylinder head, a cylinder cover fixed on the top surface of the cylinder head and a cylinder body fixed on the bottom surface of the cylinder head. A combustion chamber is arranged in the cylinder body, and a piston is arranged in the combustion chamber. The piston drives the crankshaft in the crankcase below to rotate through a connecting rod, and an intake channel and an exhaust channel connected to the top of the combustion chamber are arranged in the cylinder head. Valves are arranged at the intake channel and the exhaust channel. A camshaft and a rocker shaft are also arranged in the cylinder head. A rocker arm is arranged on the rocker shaft. One end of the rocker arm abuts against a cam on the camshaft, and the other end abuts against the top of the valve. The rocker arm is driven to swing by the rotation of the camshaft, and then the valve is driven to move to realize the intake and exhaust of the combustion chamber. The exhaust gas discharged from the combustion chamber through the exhaust channel may be incompletely burned. Therefore, the exhaust gas discharged from the exhaust channel needs to be further purified to reduce the content of harmful gases. For this reason, an air replenishing structure is also provided on the cylinder head, that is, external air is introduced into the exhaust channel, and further mixed and reacted with the high-temperature exhaust gas in the exhaust channel to achieve purification.

[0003] For example, the patent document (200520017295.X) discloses a secondary air intake device installation structure for a motorcycle, including a cylinder head of a parallel twin-cylinder engine, wherein the cylinder head is provided with two independent exhaust passages connected to the exhaust pipe, each exhaust passage is provided with a secondary air intake passage, and the secondary air intake device is connected to the secondary air intake passage via bolts, and the secondary air intake device is arranged at the outer side of the corresponding exhaust pipe, close to the connecting bolt hole where the exhaust pipe and the cylinder head exhaust passage are connected, and through the setting of the secondary air intake passage, external air is introduced to further mix and react with the exhaust gas in the exhaust passage, and the inner end of the secondary air intake passage is facing the inner end port of the exhaust passage, and the exhaust gas discharged from the exhaust passage has a certain speed and impact force, so the exhaust gas may impact the secondary air intake passage, and then directly leak out from the secondary air intake passage to pollute the environment. Summary of the invention

[0004] The purpose of the present invention is to solve the above problems in the prior art and to propose an air supply structure for a motorcycle engine to solve the problem of direct leakage when the existing motorcycle performs secondary purification of exhaust gas.

[0005] The object of the present invention can be achieved through the following technical solutions: an air supply structure for a motorcycle engine, the engine includes a cylinder head with an exhaust channel, the air supply structure includes an air supply channel opened on the cylinder head from top to bottom, the upper end of the air supply channel is connected to the outside, and the lower end of the air supply channel is inclined toward the inner end of the exhaust channel, characterized in that the lower end port of the air supply channel penetrates to the top wall of the exhaust channel, and the top wall of the exhaust channel has a downwardly protruding guide convex portion, the guide convex portion is located between the lower end port of the air supply channel and the inner end port of the exhaust channel and close to the edge of the lower end port of the air supply channel, and the guide convex portion is lower than the lower end port of the air supply channel.

[0006] The inner end of the exhaust passage is connected to the top of the combustion chamber, and the outer end is connected to the exhaust pipe. The exhaust gas after combustion and work in the combustion chamber is discharged through the exhaust passage. In order to prevent some of the exhaust gas that is not fully burned from being discharged directly, the cylinder head is provided with an air supply passage. The air supply passage introduces external air into the exhaust passage, so that the exhaust gas can react with the air introduced into the air supply passage again when it is still in a high temperature state, thereby reducing the emission of harmful gases such as carbon monoxide and achieving purification of the exhaust gas. The lower end of the air supply passage is inclined toward the inner end of the exhaust passage, so that the air entering the air supply passage and the exhaust gas discharged from the exhaust passage can form convection, so that the two can be fully mixed and reacted, thereby improving the purification effect. In view of the lower end of the air supply passage The exhaust channel is inclined toward the inner end, and there is a situation where the exhaust gas directly impacts the air supply channel, causing direct leakage of the exhaust gas and affecting the purification effect. For this reason, a downwardly protruding guide bulge is provided on the top wall of the exhaust channel, and the guide bulge is located at the side edge of the lower end port of the air supply channel close to the inner end of the exhaust channel, and the guide bulge is lower than the lower end port of the air supply channel. Therefore, the exhaust gas with a certain impact speed discharged from the exhaust channel toward the lower end port of the air supply channel will change its flow direction under the guidance of the guide bulge, avoiding the exhaust gas directly impacting the lower end port of the air supply channel, thereby avoiding the exhaust gas from being directly discharged from the air supply channel and causing exhaust gas leakage, affecting the purification effect, and of course, it can also avoid the formation of carbon deposits on the inner wall of the air supply channel.

[0007] In the above-mentioned air supply structure of the motorcycle engine, the guide convex part has a guide surface, the inner end of the guide surface is connected to the top wall of the exhaust channel, and the outer end of the guide surface is lower than the lower end port of the air supply channel and faces the outer end port of the exhaust channel. Part of the exhaust gas flows along the top wall of the exhaust channel to the guide surface, and flows to the outer end port of the exhaust channel under the action of the guide surface, avoiding direct impact on the lower end port of the air supply channel, and the air flowing downward in the air supply channel can form cross convection with the exhaust gas, so that the two are fully mixed and reacted.

[0008] In the above-mentioned motorcycle engine air supply structure, the width of the guide convex part is larger than the diameter of the lower end port of the air supply channel. The guide convex part fully shields the lower end port of the air supply channel to prevent the exhaust gas from directly impacting the lower end port of the air supply channel.

[0009] In the above-mentioned air supply structure of the motorcycle engine, the exhaust channel includes an exhaust main channel whose outer end is used to connect to the exhaust pipe and two exhaust branch channels whose inner ends are used to connect to the combustion chamber. The flow cross-sectional area of ​​the exhaust main channel is larger than the flow cross-sectional area of ​​the exhaust branch channel. The outer ends of the two exhaust branch channels are connected to the exhaust main channel after merging. The guide convex part is located on the top wall of the junction of the two exhaust branch channels. The flow cross-sectional area of ​​the exhaust branch channel is small, while the flow cross-sectional area of ​​the junction of the two exhaust branch channels is large. Therefore, when the exhaust gas enters the junction from the exhaust branch channel, the flow velocity will rapidly decrease. Therefore, the exhaust gas can be mixed with the air entering the air supply channel at a lower flow velocity, so that the two are mixed more fully, avoiding the exhaust gas impact velocity being too large and directly bringing the air out of the exhaust channel.

[0010] In the above-mentioned motorcycle engine air supply structure, there are two guide surfaces on the guide convex part, and the two guide surfaces are respectively arranged opposite to the two exhaust paths. The two guide surfaces are for the exhaust gas discharged from the two exhaust paths, so that the exhaust gas is mixed with the air after merging at the junction of the two exhaust paths.

[0011] In the above-mentioned air supply structure of the motorcycle engine, the guide convex part also has a connection surface, which faces the outer end port of the exhaust channel, and the upper end of the connection surface smoothly transitions with the inner wall of the lower end of the air supply channel, and the lower end of the connection surface smoothly transitions with the guide surface. The connection surface is used to guide the air entering the air supply channel, so that the air tilts downward and generates cross convection with the exhaust gas at the confluence of the two exhaust channels, ensuring that the two are fully mixed and reacted.

[0012] In the air supply structure of the motorcycle engine, the air supply channel is straight, and the upper end of the air supply channel extends obliquely to the edge of the top of the cylinder head, thereby reducing the resistance of air passing through the air supply channel and ensuring the air intake efficiency of the air in the air supply channel.

[0013] In the above-mentioned air supply structure of the motorcycle engine, the cylinder head has a top surface for cooperating with the cylinder cover, an air inlet hole is opened at the edge of the top surface of the cylinder head, and the upper end of the air supply channel is connected to the air inlet hole. When the cylinder cover is assembled on the cylinder head, the air inlet hole can be covered to avoid direct exposure and the entry of foreign matter.

[0014] In the above-mentioned air supply structure of the motorcycle engine, the cylinder head has a mounting portion for supporting the camshaft, the mounting portion extends to the side wall of the cylinder head, and the air inlet is opened at the connection between the mounting portion and the side wall of the cylinder head. The connection between the mounting portion and the side wall of the cylinder head has a higher structural strength, thereby ensuring the overall strength after the air inlet is opened.

[0015] Compared with the prior art, the air supply structure of the motorcycle engine has the following advantages:

[0016] 1. Since the lower end of the air supply channel is inclined toward the inner end of the exhaust channel, the air entering the air supply channel and the exhaust gas discharged from the exhaust channel can form convection, so that the two are fully mixed and reacted, thereby improving the purification effect.

[0017] 2. Since a guide convex portion is provided on the top wall of the exhaust channel, and the guide convex portion is located at the edge of one side of the lower end port of the air supply channel close to the inner end of the exhaust channel, the exhaust gas with a certain impact velocity discharged from the exhaust channel toward the lower end port of the air supply channel will change its flow direction under the guidance of the guide convex portion, thereby preventing the exhaust gas from directly impacting the lower end port of the air supply channel, thereby preventing the exhaust gas from being directly discharged from the air supply channel and causing exhaust gas leakage, thereby affecting the purification effect.

[0018] 3. Since the flow cross-sectional area at the confluence of the two exhaust channels is large, the flow velocity of the exhaust gas will rapidly decrease when it enters the confluence from the exhaust channels. The exhaust gas can be mixed with the air entering the air supply channel at a lower flow rate, making the two mixed more fully, avoiding the exhaust gas impact velocity being too high and directly carrying the air out of the exhaust channel. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the three-dimensional structure of the cylinder head.

[0020] Figure 2 This is a three-dimensional structural diagram of the cylinder head from another perspective.

[0021] Figure 3 It is a structural side view of the cylinder head.

[0022] Figure 4 yes Figure 2 A magnified view of the structure at center.

[0023] Figure 5 yes Figure 3 Structural cross-section view at BB in the middle.

[0024] Figure 6 yes Figure 5 Enlarged view of the structure at C in the middle.

[0025] Figure 7 It is a schematic diagram of the three-dimensional structure when the cylinder head is cut open.

[0026] Figure 8 yes Figure 7 Enlarged view of the structure at D in the middle.

[0027] In the figure, 1, cylinder head; 11, mounting part; 2, exhaust channel; 21, exhaust main channel; 22, exhaust branch channel; 3, air supply channel; 31, air inlet hole; 4, guide convex part; 41, guide surface; 42, connecting surface. DETAILED DESCRIPTION

[0028] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.

[0029] like Figures 1 to 5 As shown, a gas replenishment structure of a motorcycle engine, the motorcycle engine includes a cylinder head 1, an exhaust channel 2 is provided in the cylinder head 1, the inner end of the exhaust channel 2 is communicated with the combustion chamber, and the outer end is used to connect to the exhaust pipe, the inner end of the exhaust channel 2 is located on the bottom surface of the cylinder head 1, and the outer end is located on the side wall, so the exhaust channel 2 is arranged in an arc shape as a whole, and the outer end is higher than the inner end, the gas replenishment structure includes a gas replenishment channel 3 opened on the cylinder head 1 from top to bottom, the cylinder head 1 has a top surface for matching with the cylinder cover, the cylinder head 1 has a mounting portion 11 for supporting the camshaft, the mounting portion 11 extends to the side wall of the cylinder head 1, an air inlet hole 31 is opened at the connection between the mounting portion 11 and the side wall of the cylinder head 1, and the gas replenishment channel 3 is straight The shape of the present invention is that the upper end of the air supply channel 3 is inclined to extend to the top of the cylinder head 1 and is connected with the air inlet hole 31, the lower end port of the air supply channel 3 penetrates into the top wall of the exhaust channel 2, and the lower end of the air supply channel 3 is inclined toward the inner end of the exhaust channel 2, and the top wall of the exhaust channel 2 is provided with a downwardly protruding guide convex portion 4, the guide convex portion 4 is located between the lower end port of the air supply channel 3 and the inner end port of the exhaust channel 2 and close to the edge of the lower end port of the air supply channel 3, and the guide convex portion 4 is lower than the lower end port of the air supply channel 3, the exhaust gas with a certain impact velocity discharged from the exhaust channel 2 toward the lower end port of the air supply channel 3 will change its flow direction under the guidance of the guide convex portion 4, so as to prevent the exhaust gas from directly impacting the lower end port of the air supply channel 3.

[0030] Combination Figure 6 , Figure 7 , Figure 8 As shown, the exhaust channel 2 includes an exhaust main channel 21 and two exhaust branch channels 22. The outer end of the exhaust main channel 21 penetrates the side wall of the cylinder head 1, and the inner ends of the two exhaust branch channels 22 are used to connect to the combustion chamber. The outer ends of the two exhaust branch channels 22 are connected to the inner end of the exhaust main channel 21 after merging. The flow cross-sectional area of ​​the exhaust main channel 21 is larger than the flow cross-sectional area of ​​the exhaust branch channels 22. The guide protrusion 4 is located on the top wall where the two exhaust branch channels 22 merge. The width of the guide protrusion 4 is greater than the caliber of the lower end port of the air supply channel 3. The guide protrusion 4 is provided with two guide surfaces 41. The inner ends of the two guide surfaces 41 are connected to the top wall of the exhaust channel 2 and face their respective exhaust channels 22. The outer ends of the guide surfaces 41 are lower than the lower end port of the air supply channel 3 and face the outer end port of the exhaust channel 2. The guide protrusion 4 is also provided with a connecting surface 42, which faces the outer end port of the exhaust channel 2. The upper end of the connecting surface 42 smoothly transitions with the inner wall of the lower end of the air supply channel 3, and the lower end of the connecting surface 42 smoothly transitions with the guide surface 41.

[0031] The specific embodiments described herein are merely examples of the spirit of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in similar ways, but they will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

[0032] Although the terms such as cylinder head 1, mounting portion 11, exhaust passage 2 are used more frequently in this article, the possibility of using other terms is not excluded. These terms are used only to more conveniently describe and explain the essence of the present invention; interpreting them as any additional restrictions is contrary to the spirit of the present invention.

Claims

1. An air supply structure for a motorcycle engine, the engine comprising a cylinder head (1) having an exhaust passage (2), the air supply structure comprising an air supply passage (3) opened from top to bottom on the cylinder head (1), the upper end of the air supply passage (3) being connected to the outside, and the lower end of the air supply passage (3) being inclined toward the inner end of the exhaust passage (2), characterized in that: The lower end port of the air supply channel (3) penetrates the top wall of the exhaust channel (2), and the top wall of the exhaust channel (2) is provided with a downwardly protruding flow guide protrusion (4), which is located between the lower end port of the air supply channel (3) and the inner end port of the exhaust channel (2) and close to the edge of the lower end port of the air supply channel (3), and the flow guide protrusion (4) is lower than the lower end port of the air supply channel (3); the width of the flow guide protrusion (4) is greater than the diameter of the lower end port of the air supply channel (3); the exhaust channel (2) comprises an exhaust main channel (21) for connecting to an exhaust pipe at an outer end and two exhaust branch channels (22) for connecting to a combustion chamber at inner ends; the outer ends of the two exhaust branch channels (22) are connected to the exhaust main channel (21) after merging, and the flow guide protrusion (4) is located on the top wall at the merging point of the two exhaust branch channels (22).

2. The air supply structure of a motorcycle engine according to claim 1, characterized in that: The guide convex portion (4) has a guide surface (41), the inner end of the guide surface (41) is connected to the top wall of the exhaust channel (2), and the outer end of the guide surface (41) is lower than the lower end port of the air supply channel (3) and faces the outer end port of the exhaust channel (2).

3. The air supply structure of a motorcycle engine according to claim 2, characterized in that: There are two flow-guiding surfaces (41) on the flow-guiding protrusion (4), and the two flow-guiding surfaces (41) are respectively arranged opposite to the two exhaust branch channels (22).

4. The air supply structure of a motorcycle engine according to claim 3, characterized in that: The guide protrusion (4) also has a connection surface (42), the connection surface (42) faces the outer end port of the exhaust channel (2), the upper end of the connection surface (42) smoothly transitions to the inner wall of the lower end of the air supply channel (3), and the lower end of the connection surface (42) smoothly transitions to the guide surface (41).

5. The air supply structure of a motorcycle engine according to claim 1 or 2, characterized in that: The air supply channel (3) is straight, and the upper end of the air supply channel (3) extends obliquely to the edge of the top end of the cylinder head (1).

6. The air supply structure of a motorcycle engine according to claim 5, characterized in that: The cylinder head (1) has a top surface for cooperating with the cylinder cover, an air inlet hole (31) is provided at the edge of the top surface of the cylinder head (1), and the upper end of the air supply channel (3) is connected to the air inlet hole (31).

7. The air supply structure of a motorcycle engine according to claim 6, characterized in that: The cylinder head (1) has a mounting portion (11) for supporting a camshaft, the mounting portion (11) extending to a side wall of the cylinder head (1), and the air inlet hole (31) is provided at a connection between the mounting portion (11) and the side wall of the cylinder head (1).

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