Two-stroke engine air pump assembly integration and auxiliary scavenging and lubricating device

Abstract

The invention discloses a two-stroke engine air pump assembly integration and auxiliary scavenging and lubricating device, and belongs to the technical field of internal combustion engines. The engine comprises an engine body and an air pump assembly, the air pump assembly is installed on one side of the engine body, and a first crankshaft on the engine body and a second crankshaft on the air pump assembly coincide in center line and are connected through a connecting piece. One first crankcase on the engine is communicated with a second crankcase on the air pump assembly, a first crankshaft on the engine is located in the first crankcase, and a second crankshaft on the air pump assembly is located in the second crankcase. Compared with the prior art, a belt pulley, a belt and a tensioning device used for driving the air pump are omitted, and the mode that the first crankshaft and the second crankshaft are connected is adopted, so that the structure is simple, and reliability is high; according to the design, through airflow movement between the second crankcase and the first crankcase, the ventilation quality of the engine can be improved, and the auxiliary lubrication effect on the second crankshaft friction pair can be achieved.

Description

Technical Field

[0001] This invention relates to the integration of a two-stroke engine air pump assembly and an auxiliary scavenging and lubrication device, belonging to the field of internal combustion engine technology. Background Technology

[0002] The existing air pump assemblies on the engine are mainly driven by belts, chains, cams, gears, etc., for example... Figure 1 As shown, an air pump assembly 2 is located on the upper part of the cylinder block 105, above the engine crankshaft. The top of the air pump assembly 2 is provided with an air pump assembly inlet 201 and an air pump assembly outlet 202. An air pump assembly pulley 602 is provided on one side of the air pump assembly 2. A throttle valve assembly 109 is provided below the cylinder block 105. A crankshaft pulley 601 is installed at the connection between the throttle valve assembly 109 and the cylinder block 105. A belt 604 is sleeved between the crankshaft pulley 601 and the air pump assembly pulley 602. A tensioning device 603 is also provided on the cylinder block 105 to tension the belt 604. The design and modification of the engine are relatively large, and the requirements for the lateral dimension space of the engine are relatively high.

[0003] In addition, the existing scavenging structure of two-stroke engines mainly consists of a crankcase scavenging structure, a scavenging pump assembly scavenging structure, or a combination of both. Generally, two-stroke engines have a scavenging port at the bottom of the cylinder, and the position of the scavenging port is used to partially or fully open or close the scavenging port during the vertical movement of the piston assembly. An exhaust port is usually located above the cylinder scavenging port, and scavenging is completed through the cooperation of the piston assembly and the exhaust port. However, this design has the following drawbacks:

[0004] 1) The air pump assembly is difficult to modify within the existing engine layout and integrated design;

[0005] 2) The air pump assembly drive mechanism is complex and has high requirements for constraint space;

[0006] 3) The scavenging efficiency of two-stroke engines is low or the matching scavenging pump assembly results in high scavenging costs. Summary of the Invention

[0007] The purpose of this invention is to solve the problems of complex structure and difficult layout of the integrated air pump assembly in the existing two-stroke air-jet engine. It proposes an integrated air pump assembly for two-stroke engines and an auxiliary scavenging and lubrication device, which can achieve the requirements of simple improvement and design and easy layout. At the same time, by utilizing the kinematic relationship between the piston assembly of the engine and the piston assembly of the air pump assembly, this invention achieves the integrated design of the air pump assembly and the engine with minimal modification and low cost increase, and is beneficial to engine scavenging and air pump assembly lubrication.

[0008] The two-stroke engine air pump assembly integration and auxiliary scavenging and lubrication device includes an engine and an air pump assembly. The air pump assembly is mounted on one side of the engine. The center lines of the first crankshaft on the engine and the second crankshaft on the air pump assembly coincide and are connected by a coupling.

[0009] One of the first crankcases on the engine is connected to the second crankcase on the air pump assembly, and the first crankshaft on the engine is located in the first crankcase, while the second crankshaft on the air pump assembly is located in the second crankcase.

[0010] The airflow direction in the second crankcase, the first crankcase, and the connection point between them resonates with the motion of the engine piston assembly and the air pump piston assembly in the following way.

[0011] Ψ = F(N, S, P, D) / L,

[0012] Where Ψ represents the final effect of the resonance relationship, F represents the function, N represents the engine speed, S represents the stroke, P represents the gas pressure, L represents the length of the connecting pipe between the first crankcase and the second crankcase, and D represents the diameter of the connecting pipe between the first crankcase and the second crankcase.

[0013] Furthermore, the airflow direction is consistent with the movement direction of the piston assembly on the air pump assembly, and also consistent with the movement direction of the piston assembly on the corresponding cylinder of the engine.

[0014] As a preferred example, the top of the air pump assembly is provided with an air pump assembly inlet and an exhaust port, wherein the air pump assembly inlet is connected to the outside atmosphere, and the exhaust port is connected to the air jet system.

[0015] Furthermore, the air-assisted injection system is an air-assisted fuel injection system that is integrated with the fuel injection system consisting of the engine and air pump assembly. When in operation, fuel at a certain pressure is injected into the combustion chamber under the action of air at a certain pressure, which greatly enhances the atomization effect of the fuel and thus helps combustion.

[0016] As a preferred example, the engine cylinder has an exhaust port on each of its two opposite sidewalls, and a scavenging port on each of its two opposite sidewalls, with the scavenging port on each sidewall located below the exhaust port.

[0017] As a preferred example, the engine also includes an engine piston assembly, and the air pump assembly contains an air pump assembly piston assembly. One of the engine's first crankcases is connected to the second crankcase on the air pump assembly via a pipe, and the corresponding engine piston assembly and air pump assembly piston assemblies move in opposite directions.

[0018] As a preferred example, the air pump assembly is mounted on the outer wall of the first crankcase of the engine or the cylinder block of the engine via a bracket or directly. The second crankcase on the air pump assembly is connected to one of the first crankcases of the engine via a connecting pipe.

[0019] As a preferred example, the first crankcase containing the engine piston assembly, which moves in the opposite direction to the piston assembly of the air pump assembly, is directly connected to the second crankcase.

[0020] As a preferred example, the connecting element includes a spline, a coupling, or a flange, and the first crankshaft of the engine and the second crankshaft of the air pump assembly are connected by a spline, a coupling, or a flange.

[0021] As a preferred example, the engine is a two-stroke air-injection engine, which is a single-cylinder engine, a twin-cylinder engine, or a multi-cylinder engine.

[0022] As a preferred example, the second crankshaft of the air pump assembly is provided with a second crankshaft friction pair, which is in contact with the side wall of the second crankcase.

[0023] The beneficial effects of this invention are as follows: Compared with the prior art, 1) it eliminates the pulley, belt, and tensioning device used to drive the air pump, and replaces it with direct crankshaft drive, that is, the connection between the first crankshaft and the second crankshaft, which makes the structure simple and greatly improves the transmission efficiency and reliability; 2) the second crankcase and the first crankcase of one cylinder of the connected engine have air pump pistons and engine pistons moving in opposite directions. This design, through the airflow movement between the second crankcase and the first crankcase, can not only improve the air exchange quality of the engine, but also provide auxiliary lubrication for the friction pair of the second crankshaft. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the integration of an existing engine and air pump assembly;

[0025] Figure 2 This is a schematic diagram of the integration of the engine and the air pump assembly when the air pump piston is at top dead center.

[0026] Figure 3 This is a schematic diagram of the airflow between the first crankcase and the second crankcase when the air pump piston is at top dead center, according to the present invention (the arrows indicate the airflow direction);

[0027] Figure 4 This is a schematic diagram of the integration of the engine and the air pump assembly when the air pump piston is at bottom dead center according to the present invention;

[0028] Figure 5 This is a schematic diagram of the airflow between the first crankcase and the second crankcase when the air pump piston is at bottom dead center, according to the present invention (the arrows indicate the airflow direction);

[0029] In the diagram: Engine 1; Engine cylinder head 101; Engine exhaust port 102; Scavenging port 103; Engine piston 104; Cylinder block 105; Engine connecting rod 106; First crankshaft 107; First crankcase 108; Throttle assembly 109; Air pump assembly 2; Air pump assembly inlet 201; Exhaust port 202; Air pump piston 203; Air pump connecting rod 204; Second crankshaft 205; Second crankcase 206; Second crankshaft friction pair 207; Connecting component 301; Connecting pipe 401; Bracket 501; Crankshaft pulley 601; Air pump assembly pulley 602; Tensioner 603; Belt 604. Detailed Implementation

[0030] To facilitate a clear understanding of the technical means, creative features, objectives, and effects of this invention, the invention will be further described below in conjunction with specific illustrations.

[0031] like Figure 2-5 As shown, the two-stroke engine air pump assembly integration and auxiliary scavenging and lubrication device includes an engine 1 and an air pump assembly 2. The air pump assembly 2 is installed on one side of the engine 1. The center line of the first crankshaft 107 on the engine 1 coincides with that of the second crankshaft 205 on the air pump assembly 2, and they are connected by a connector 301, so that the rotational speed of the air pump assembly 2 is the same as that of the engine 1.

[0032] One of the first crankcases 108 on engine 1 is connected to the second crankcase 206 on air pump assembly 2, and the first crankshaft 107 on engine 1 is located in the first crankcase 108, and the second crankshaft 205 on air pump assembly 2 is located in the second crankcase 206.

[0033] The airflow direction in the second crankcase 206, the first crankcase 108, and the connection point between them resonates with the movement of the engine piston assembly and the air pump piston assembly in the following way.

[0034] Ψ = F(N, S, P, D) / L,

[0035] Where Ψ represents the final effect of the resonance relationship, F represents the function, N represents the engine speed, S represents the stroke, P represents the gas pressure, L represents the length of the connecting pipe between the first crankcase 108 and the second crankcase 206, and D represents the diameter of the connecting pipe between the first crankcase 108 and the second crankcase 206.

[0036] It should be noted that the resonance relationship expression in this invention is only used for qualitative analysis of airflow direction.

[0037] Furthermore, the airflow direction is consistent with the movement direction of the piston assembly on the air pump assembly, and also consistent with the movement direction of the piston assembly on the corresponding cylinder of the engine.

[0038] The top of the air pump assembly 2 is provided with an air pump assembly inlet 201 and an exhaust port 202. The air pump assembly inlet 201 is connected to the outside atmosphere, and the exhaust port 202 is connected to the external air jet system.

[0039] Engine 1 has an exhaust port 102 on each of the two opposite side walls of the cylinder, and a scavenging port 103 on each of the two opposite side walls of the cylinder. The scavenging port 103 on each side wall of engine 1 is located below the exhaust port 102.

[0040] Engine 1 also contains an engine piston assembly, and air pump assembly 2 contains an air pump piston assembly. One of the engine's first crankcases is connected to the second crankcase on the air pump assembly via a pipe. The corresponding engine piston assembly and air pump piston assembly move in opposite directions.

[0041] The air pump assembly 2 is mounted on the first crankcase 108 of the engine 1 or the outer wall of the cylinder block 105 of the engine 1 via a bracket 501 or directly. The second crankcase 206 on the air pump assembly 2 is connected to one of the first crankcases 108 of the engine 1 via a connecting pipe 401.

[0042] It should be noted that when the engine is a two-cylinder engine, the engine assembly 1 has two sets of engine piston assemblies inside. One set of engine piston assemblies moves in the same direction as the air pump piston assembly, while the other set of engine piston assemblies moves in the opposite direction to the air pump piston assembly. The first crankcase 108, where the engine piston assembly moves in the opposite direction to the air pump piston assembly, is located, is connected to the second crankcase 206 of the air pump assembly 2 through a connecting pipe 401.

[0043] In another embodiment, when the engine is a two-cylinder engine, the engine assembly 1 has two sets of engine piston assemblies inside. One set of engine piston assemblies moves in the same direction as the air pump piston assembly, while the other set of engine piston assemblies moves in the opposite direction to the air pump piston assembly. The first crankcase 108, where the engine piston assembly moves in the opposite direction to the air pump piston assembly, is located, is directly connected to the second crankcase 206 of the air pump assembly 2 through a connecting pipe 401. The purpose is to increase the volume of the first crankcase 108 of the engine 1, thereby suppressing airflow fluctuations.

[0044] The connecting component 301 includes a spline, a coupling, or a flange, and the first crankshaft 107 of the engine 1 and the second crankshaft 205 of the air pump assembly 2 are connected by a spline, a coupling, or a flange.

[0045] Engine 1 is a two-stroke air-injection engine, which can be a single-cylinder, twin-cylinder, or multi-cylinder engine.

[0046] The second crankshaft 205 of the air pump assembly 2 is provided with a second crankshaft friction pair 207, which is in contact with the side wall of the second crankcase 206.

[0047] It should be noted that,

[0048] The cylinder block 105 of the engine 1 is provided with an engine cylinder head 101 at the top, and a throttle valve assembly 109 is provided at the bottom of the cylinder block 105 of the engine 1, and the throttle valve assembly 109 is connected to the first crankcase 108.

[0049] The air pump piston assembly includes an air pump connecting rod 204 and an air pump piston 203; one end of the air pump connecting rod 204 is connected to the second crankshaft 205, and the other end is connected to the air pump piston 203.

[0050] The engine piston assembly includes an engine connecting rod 106 and an engine piston 104; one end of the engine connecting rod 106 is connected to the first crankshaft 107, and the other end is connected to the engine piston 104.

[0051] It should also be noted that when it is a two-cylinder engine, the number of all other components inside the engine 1 is two, except for the first crankshaft 107, which has one. The two first crankcases 108 are separated. When one of the engine pistons 104 in the engine 1 moves upward away from the air pump assembly, the other engine piston 104 moves downward away from the air pump assembly, and the air pump piston 203 on the air pump 2 moves upward.

[0052] Working principle: It should be noted that the following mainly describes the working relationship between the first crankcase 108, the first crankshaft 107, the engine piston 104, which are close to the air pump assembly, and the second crankcase, the second crankshaft, and the air pump piston inside the air pump, as follows:

[0053] like Figure 2 and Figure 3 As shown, when one of the engine pistons 104 moves upward from the bottom dead center, the cylinder block 105 enters the intake and compression strokes. During the upward movement of the engine piston 104, fresh air is drawn into the first crankcase 108 through the throttle valve assembly 109. The fresh gas in the first crankcase 108 enters the combustion chamber through the scavenging port 103. Before the exhaust port 102 is closed, the residual exhaust gas from the previous cycle in the combustion chamber is discharged from the engine 1 through airflow, thus venting the combustion exhaust gas from the previous cycle.

[0054] As the engine piston 104 continues its upward movement, successively closing the scavenging port 103 and the exhaust port 102, it begins to compress the gas in the combustion chamber. During this process, the air-fuel mixture pressure in the first crankcase 108 gradually decreases, the air pump piston 203 begins to move from top dead center to bottom dead center, the air pump assembly 2 begins its intake stroke, and the gas pressure in the second crankcase 206 gradually increases. At this time, under the action of the engine piston 104 and the air pump piston 203, the airflow in the second crankcase 206 enters the first crankcase 108 through the 401 connecting pipe, thereby increasing the gas pressure in the first crankcase 108.

[0055] Therefore, under the influence of this airflow movement, it is beneficial to the combustion chamber scavenging and intake of engine 1, improving the quality of air exchange, and also helps the downward movement of the air pump piston 203. It is also beneficial to the renewal of the oil-air mixture in the second crankcase 206, thereby maintaining the oil content in the oil-air mixture and playing an auxiliary role in the lubrication of the second crankshaft friction pair 207.

[0056] like Figure 4 , Figure 5 As shown, when the engine piston 104 moves downward from top dead center, the cylinder block 105 enters the power and exhaust strokes. As the engine piston 104 moves downward, it pushes the first crankshaft 107 to perform external work and compresses the gas in the first crankcase 108. The engine piston 104 continues to move downward, opening the exhaust port 102 to begin exhausting gas. When the engine piston 104 moves further downward, the scavenging port 103 opens, allowing some of the air-fuel mixture in the first crankcase 108 to enter the combustion chamber through the scavenging port 103, thus scavenging the exhaust gas out of the combustion chamber and improving the scavenging quality.

[0057] During this process, the air pump piston 203 begins to move from bottom dead center to top dead center, that is, it begins the compression stroke, increasing the air pump pressure and causing the gas pressure in the second crankcase 206 to decrease. At this time, under the action of the engine piston 104 and the air pump piston 203, the airflow in the first crankcase 108 enters the second crankcase 206 through the connecting pipe 401, so that the air-fuel mixture pressure in the second crankcase 206 does not drop sharply and maintains a certain pressure.

[0058] Therefore, under the influence of this airflow movement, it can not only help reduce the resistance of the engine piston 104 moving downward, but also help the air pump piston 203 move upward, and help the oil-air mixture accumulate in the second crankcase 206, which can play a certain lubricating role for the second crankshaft friction pair 207.

[0059] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and various changes and modifications can be made without departing from the spirit and scope of the invention, all of which fall within the scope of the claims. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A two-stroke engine air pump assembly integration and auxiliary scavenging and lubrication device, comprising an engine and an air pump assembly, characterized in that: The air pump assembly is mounted on one side of the engine, and the center lines of the first crankshaft on the engine and the second crankshaft on the air pump assembly are coincident and connected by a coupling. One of the first crankcases on the engine is connected to the second crankcase on the air pump assembly, and the first crankshaft on the engine is located in the first crankcase, while the second crankshaft on the air pump assembly is located in the second crankcase. The airflow direction of the second crankcase, the first crankcase, and the connection between them resonates with the movement of the engine piston assembly and the air pump piston assembly in the following way. Ψ = F(N, S, P, D) / L, Where Ψ represents the final effect of the resonance relationship, F represents the function, N represents the engine speed, S represents the stroke, P represents the gas pressure, L represents the length of the connecting pipe between the first crankcase and the second crankcase, and D represents the diameter of the connecting pipe between the first crankcase and the second crankcase. Furthermore, the airflow direction is consistent with the movement direction of the piston assembly on the air pump assembly, and also consistent with the movement direction of the piston assembly on the corresponding cylinder of the engine.

2. The two-stroke engine air pump assembly integration and auxiliary scavenging and lubrication device according to claim 1, characterized in that: The top of the air pump assembly is provided with an air pump assembly inlet and an exhaust port, wherein the air pump assembly inlet is connected to the outside atmosphere, and the exhaust port is connected to an air-jet system.

3. The two-stroke engine air pump assembly integration and auxiliary scavenging and lubrication device according to claim 1, characterized in that: The engine has exhaust ports on two opposite side walls of the cylinder, and scavenging ports on two opposite side walls of the cylinder, with each scavenging port located below the exhaust port.

4. The two-stroke engine air pump assembly integration and auxiliary scavenging and lubrication device according to claim 1, characterized in that: The engine also contains an engine piston assembly, and the air pump assembly contains an air pump assembly piston assembly. One of the engine's first crankcases is connected to the second crankcase on the air pump assembly via a pipe. The corresponding engine piston assembly and air pump assembly piston assemblies move in opposite directions.

5. The two-stroke engine air pump assembly integration and auxiliary scavenging and lubrication device according to claim 1, characterized in that: The air pump assembly is mounted on the first crankcase of the engine or the outer wall of the engine cylinder block via a bracket or directly. The second crankcase on the air pump assembly is connected to one of the first crankcases of the engine via a connecting pipe.

6. The two-stroke engine air pump assembly integration and auxiliary scavenging and lubrication device according to claim 1, characterized in that: The first crankcase, which contains the engine piston assembly and the second crankcase, is directly connected to the piston assembly, which moves in the opposite direction to the air pump assembly piston assembly.

7. The two-stroke engine air pump assembly integration and auxiliary scavenging and lubrication device according to claim 1, characterized in that: The connecting components include splines, couplings, or flanges, and the first crankshaft of the engine and the second crankshaft of the air pump assembly are connected by splines, couplings, or flanges.

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