A crankcase with an integrated air pump for a two-stroke heavy oil piston engine

Abstract

This invention discloses a crankcase for an integrated air pump in a two-stroke heavy oil piston engine. Addressing the technical problem that an existing prototype's external high-pressure air source solution is unsuitable for drones, this invention proposes a crankcase design with an integrated air pump. By driving the air pump through the crankshaft, an external air cylinder can be replaced, achieving the effect of an external high-pressure air source. This integrated air pump crankcase structure is simple and practical, better meeting the requirements of lightweight design and high power-to-weight ratio in drone engines.

Description

Technical Field

[0001] This invention relates to the field of unmanned aerial vehicle (UAV) engine technology, and in particular to a crankcase for an integrated air pump in a two-stroke heavy oil piston engine. Background Technology

[0002] One of the technical approaches used in heavy fuel atomization for two-stroke piston engines is air-assisted injection technology. The principle of air-assisted injection technology is to use the supersonic aerodynamic force of high-pressure compressed air leaving the nozzle to overcome the surface tension of the fuel and promote droplet breakage, so as to obtain a smaller spray particle size at a relatively low injection pressure, thereby improving the atomization effect of heavy fuel.

[0003] Air-assisted jet technology requires a separate external air source. Current solutions use high-pressure air from external cylinders, which is impractical for drones. Therefore, the air pump needs to be integrated into the crankcase. Figure 1 The diagram shows a schematic of an air-assisted injection system. This system mainly consists of a high-pressure air source, a pressure regulating valve, a fuel tank, a fuel pump, a fuel pressure gauge, a fuel-air regulating valve, fuel injectors, air injectors, and an electronic control unit (ECU). The fuel injectors and air injectors are controlled independently according to a specific timing sequence, as shown below. Figure 2 As shown. By Figure 1 and Figure 2 As can be seen, within the injection pulse width, fuel is injected from the nozzle into the premixing chamber and mixed with high-pressure air, completing the initial fuel atomization. After a certain period of time (fuel-air interval), the initial fuel-air mixing is complete. When the nozzle opens, the supersonic aerodynamic force of the high-pressure gas and the tensile force of the fuel surface overcome the surface tension of the droplets, causing the droplets to undergo secondary atomization. The high-pressure air and the atomized droplets are then ejected together. During the expansion process, the high-pressure air accelerates the droplets, thereby fully atomizing the fuel.

[0004] like Figure 2 The control timing diagram of the air-assisted injection system shown is provided. The fuel injection control signal and the jet injection control signal are controlled by the ECU respectively.

[0005] In response to the existing solution of connecting an external high-pressure air source to a certain prototype, a crankcase design structure with an integrated air pump is proposed. Through crankshaft drive, a diaphragm air compressor is designed to achieve the effect of connecting an external high-pressure air source. The crankcase structure of this integrated air pump is simple and practical, and can better meet the requirements of lightweight and high power-to-weight ratio of UAV engines.

[0006] The above background information is provided only to aid in understanding the concept and technical solution of this invention. It does not necessarily belong to the prior art of this patent application. In the absence of clear evidence that the above information was disclosed on the filing date of this patent application, the above background information should not be used to evaluate the novelty and inventiveness of this application. Summary of the Invention

[0007] The main objective of this invention is to propose a crankcase for an integrated air pump in a two-stroke heavy oil piston engine. By designing a diaphragm air compressor, the effect of connecting to an external high-pressure air source is achieved. The crankcase structure of this integrated air pump is simple and practical, and can better meet the requirements of lightweight and high power-to-weight ratio of UAV engines.

[0008] Therefore, this invention proposes a crankcase for an integrated air pump in a two-stroke heavy oil piston engine.

[0009] Preferably, the present invention may also have the following technical features:

[0010] A crankcase for an integrated air pump in a two-stroke heavy oil piston engine includes a crankcase, a cylinder head, and an air auxiliary nozzle assembly. A crankshaft is installed inside the crankcase, and the crankshaft is arranged along the front-rear direction of the crankcase. The cylinder head is installed on the left and right sides of the crankcase, and the air auxiliary nozzle assembly is also installed on the cylinder head on the side facing away from the crankcase. The characteristic feature is that:

[0011] It also includes an air pump assembly, which is integrated on the rear side of the crankcase. The air pump assembly includes an air compressor cylinder head, cylinder block, cylinder liner, diaphragm, spring, piston, and connecting rod. The upper part of the cylinder block is connected to and communicates with the rear side of the crankcase. The cylinder block and the air compressor cylinder head are assembled together to form a first cavity for installing the connecting rod, cylinder liner, piston, diaphragm, and spring.

[0012] The cylinder liner is fixed inside the cylinder body, and the piston is installed inside it; the lower end of the connecting rod is hinged to the piston, and the upper end is connected to the rear end of the crankshaft through an eccentric component;

[0013] The inner wall of the cylinder is provided with a plurality of air passages arranged along the cylinder axial direction, and the lower end of the air passages is connected to the first space formed by the lower end face of the cylinder liner and the upper side of the diaphragm; the side wall of the cylinder liner is also provided with a plurality of air holes, the positions of the air holes corresponding to the positions of the air passages.

[0014] The diaphragm is installed below the cylinder liner, and its periphery is in clearance fit with the inner cavity of the air compressor cylinder head; the spring is fixed to the bottom of the inner cavity of the air compressor cylinder head, and its upper end is fixedly connected to the diaphragm.

[0015] Furthermore, the eccentric component includes a boss and an eccentric shaft. The boss is a boss structure composed of two cylinders of different sizes. An axial connecting hole is provided at the rear end of the crankshaft. The small end of the boss is interference-fitted in the connecting hole. The large end of the boss is provided with the eccentric shaft. The axis of the eccentric shaft is parallel to the axis of the crankshaft.

[0016] Furthermore, the gap between the diaphragm and the air compressor cylinder head is 0.1~0.2mm.

[0017] Furthermore, the lower part of the cylinder liner is provided with a skirt, the lower end of which abuts against the diaphragm to separate the first space.

[0018] Furthermore, the upper part of the cylinder block is provided with an extension, which extends upwards towards the cylinder block, and its front side is in contact with and sealed to the rear end face of the crankcase; the front side of the extension has an assembly groove for the connecting rod to move, and the assembly groove extends downwards and communicates with the inside of the cylinder liner.

[0019] Furthermore, a vent hole corresponding to the position of the mounting slot is provided at the lower part of the rear end of the crankcase.

[0020] Furthermore, the crankcase includes a front housing and a rear housing, which together form a second cavity for assembling the crankshaft. The two ends of the crankshaft are connected to the front housing and the rear housing respectively via bearings. A generator is installed at the front end of the front housing. The cylinder head is installed on the left and right sides of the rear housing, and the vent is provided at the rear end.

[0021] Furthermore, the cylinder block of the air pump assembly and the rear housing are integrally cast.

[0022] Furthermore, the air-assisted nozzle assembly includes components such as an injector pressure sleeve, a nozzle, an injector support, a pressure relief valve, an air nozzle, a spark plug, and a cylinder head. The injector pressure sleeve is equipped with an oil passage connector to deliver fuel to the nozzle; the injector support is equipped with an air passage connector, which is connected to the inside of the air compressor cylinder head via a pipeline.

[0023] The beneficial effects of this invention compared with the prior art include: during the downward movement of the piston, the air below the piston is squeezed towards the diaphragm, causing the diaphragm to be compressed downward by the spring. The volume change of the closed space formed by the air compressor cylinder head forms a compressed high-pressure air source. This high-pressure air source is delivered to the air nozzle premixing chamber through the air passage. When the piston moves upward, air is drawn in from the bottom of the piston. The air entering the first space from the crankshaft is added to the bottom of the piston, reducing the resistance to the upward movement of the piston. At the same time, the spring returns to its original position and lifts the diaphragm upward. The air in the first space enters the space below the diaphragm from the gap between the diaphragm and the air compressor cylinder head. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of an existing air-assisted injection system.

[0025] Figure 2 This is a control timing diagram for an air-assisted injection system in the prior art.

[0026] Figure 3This is a perspective view of the crankcase assembly of the present invention.

[0027] Figure 4 and Figure 5 This is a schematic diagram of the crankcase installation of the integrated air pump of the present invention, wherein, Figure 5 The thickened black line in the diagram represents the cross-sectional outline of the eccentric component.

[0028] Figure 6 This is a schematic diagram of the housing assembly of the present invention.

[0029] Figure 7 This is a schematic diagram of the front housing of the present invention.

[0030] Figure 8 This is a schematic diagram of the rear housing of the present invention.

[0031] Figure 9 This is a schematic diagram of the air-assisted nozzle assembly installation of the present invention. Detailed Implementation

[0032] The present invention will now be described in further detail with reference to specific embodiments and the accompanying drawings. It should be emphasized that the following description is merely exemplary and is not intended to limit the scope or application of the present invention.

[0033] Non-limiting and non-exclusive embodiments will be described with reference to the following figures, wherein the same reference numerals denote the same parts unless otherwise specifically stated.

[0034] like Figures 3-9 The crankcase of an integrated air pump for a two-stroke heavy oil piston engine, as shown, includes a crankcase 1, a cylinder head 28, and an air auxiliary nozzle assembly 2. A crankshaft 5 is installed inside the crankcase 1, and the crankshaft 5 is arranged along the front-rear direction of the crankcase 1. The cylinder head 28 is installed on the left and right sides of the crankcase 1, respectively. The air auxiliary nozzle assembly 2 is also installed on the cylinder head 28 on the side facing away from the crankcase 1. As one improvement, the following is a key reference... Figure 4 and Figure 5 It also includes an air pump assembly 3, which is integrated on the rear side of the crankcase 1. The air pump assembly 3 includes an air compressor cylinder head 37, a cylinder block 39, a cylinder liner 33, a diaphragm 35, a spring 36, a piston 34, and a connecting rod 32. The upper part of the cylinder block 39 is connected to the rear side of the crankcase 1 and communicates with the crankcase 1, so that air can enter the cylinder liner 33 through the crankcase 1. The air compressor cylinder head 37 is installed on the lower part of the cylinder block 39. After the cylinder block 39 and the cylinder head 37 are assembled together, they form a first cavity for installing the connecting rod 32, the cylinder liner 33, the piston 34, the diaphragm 35, and the spring 36.

[0035] Specifically, the cylinder liner 33 is fixed inside the cylinder body 39, and the piston 34 is installed inside it. The lower end of the connecting rod 35 is hinged to the piston 34, and the upper end is connected to the rear end of the crankshaft 5 through an eccentric member 6. Thus, when the crankshaft 5 rotates, the eccentric member 6 drives the connecting rod 32 to cause the piston 34 to reciprocate within the stroke of the cylinder liner 33. Specifically, the front part of the eccentric member 6 is connected to the crankshaft 5 to achieve coaxial rotation, and an eccentric shaft 61 is fixed on the side of the eccentric member 6 away from the crankshaft 5 (i.e., the rear part of the eccentric member 6), and the upper end of the connecting rod 32 is movably connected to the eccentric shaft 61. That is to say, when the crankshaft 5 rotates, the eccentric shaft 61 rotates in a circle around the axis of the crankshaft 5, and then transmits force to the piston 34 through the connecting rod 32, causing the piston 34 to reciprocate in the up-down direction.

[0036] The further elaboration on the connection between connecting rod 32 and crankshaft 5 in the above technical solution, combined with Figure 5 , Figure 5 The thickened black line in the diagram represents the cross-sectional outline of the eccentric component 6. The eccentric component 6 includes a boss and an eccentric shaft 61. The boss is a structure composed of two cylinders, one large and one small. An axial connecting hole 51 is provided at the rear end of the crankshaft 5, and the smaller end 63 of the boss is interference-fitted into the connecting hole 51. The larger end 62 of the boss houses the eccentric shaft 61, and the axis of the eccentric shaft 61 is parallel to the axis of the crankshaft 5.

[0037] The diaphragm 35 is installed inside the air compressor cylinder head 37, preferably a circular sheet, and its periphery is fitted with the inner cavity of the air compressor cylinder head 37 with a clearance. Preferably, the clearance between the diaphragm 35 and the air compressor cylinder head 37 is 0.1~0.2mm, more preferably 0.15mm. The spring 36 is fixed to the bottom of the inner cavity of the air compressor cylinder head 37, and its upper end is fixedly connected to the diaphragm 35. A guide post 37 is also included, which is fixed to the bottom of the air compressor cylinder head 37, and the spring 36 is sleeved on its outer side to prevent the spring 36 from twisting during compression deformation.

[0038] The inner wall of the cylinder body 39 has several air passages 391 arranged axially along the cylinder body 39. The lower end of each air passage 391 connects to the first space formed by the lower end face of the cylinder liner 33 and the upper side of the diaphragm 35. Correspondingly, the side wall of the cylinder liner 33 also has several air holes 332, the positions of which correspond to the positions of the air passages 391. Thus, when the piston 34 moves downward to a position below the air holes 332, the crankcase 1, the interior of the cylinder liner 33, the air passages 391, and the first space are connected. As the piston 34 moves downward, it compresses the air below the piston 34 towards the diaphragm 35, causing the diaphragm 35 to be compressed downward by the spring 36. The volume change of the enclosed space formed by the air compressor cylinder head 37 creates a compressed high-pressure air source. This high-pressure air source is delivered to the air nozzle premixing chamber 26 through the air passage. When the piston 34 moves upward, air is drawn in from the bottom of the piston 34. Air entering the first space from the crankcase 1 is added to the bottom of the piston 34, reducing the resistance to the upward movement of the piston 34. At the same time, the spring 36 returns to its original position and lifts the diaphragm 35 upward. Air in the first space enters the space below the diaphragm 35 from the gap between the diaphragm 35 and the air compressor cylinder head 37.

[0039] Preferably, the lower part of the cylinder liner 33 is provided with a skirt 331, the lower end of which abuts against the diaphragm 5, separating the first space. The skirt 331 increases the second space formed by the bottom of the piston 34, the skirt 331, and the diaphragm 35, increasing the air capacity and facilitating the piston 34 to compress gas and apply pressure to the diaphragm 35.

[0040] Preferably, the upper part of the cylinder block 39 is provided with an extension 392, which extends upwards from the cylinder block 39, and its front side is in contact with and sealed to the rear end face of the crankcase 1. Specifically, the front side of the extension has a mounting groove 393 for the connecting rod 32 to move, and the mounting groove 393 extends downwards and communicates with the inside of the cylinder liner 33. Moreover, the width of the mounting groove 393 is large enough, preferably to meet the main requirement of providing sufficient space for the connecting rod 32 to move.

[0041] The lower part of the rear end of the crankcase 1 is provided with a vent hole 14 corresponding to the position of the assembly groove 393, so that the air in the crankcase 1 can enter the assembly groove 393 through the vent hole 14, then enter the cylinder liner 33, and then enter the first space through the air hole 332 on the side wall of the cylinder liner 33.

[0042] For preferred embodiments of the above technical solutions, see [link to preferred embodiments]. Figures 6-8The crankcase 1 includes a front housing 12 and a rear housing 13. When the front housing 12 and the rear housing 13 are combined, they form a second cavity for assembling the crankshaft 5. Both ends of the crankshaft 5 are connected to the front housing 12 and the rear housing 13 respectively via bearings. A generator 4 is installed at the front end of the front housing 12; the cylinder head 28 is installed on the left and right sides of the rear housing 13, and an extension 391 of the cylinder block 39 is connected to the rear end. Preferably, the cylinder block 39 of the air pump assembly 3 and the rear housing 13 are integrally cast, forming an integrated design. This simplifies the component composition and ensures the sealing of the connection between the extension 391 and the crankcase 1. The crankcase 1, through its split housing design and combined machining structure, better achieves manufacturability and maintainability.

[0043] Reference Figure 9 The air-assisted nozzle assembly 2 includes components such as an injector sleeve 21, an injector nozzle 22, an injector support 23, a pressure relief valve 29, an air nozzle 24, a spark plug 27, and a cylinder head 28. The injector sleeve 21 is equipped with a fuel line connector 20 to deliver fuel to the nozzle assembly. The injector support 23 is equipped with an air line connector 25, which connects to the inside of the air compressor cylinder head 37 via a pipeline, introducing compressed air from inside the air compressor cylinder head 37 into the premixing chamber 26 of the air-assisted nozzle assembly 2. During operation, fuel is injected from the injector nozzle into the premixing chamber 26 and premixed with high-pressure air (compressed air from the air compressor cylinder head 37 introduced by the air line connector 25). The mixture is then further injected into the combustion chamber through the air nozzle and ignited by the spark plug 27. The air-assisted nozzle assembly 2 in this embodiment has the same structure as the existing air-assisted nozzle assembly 2. The feature is that the air nozzle 24, oil nozzle 22, pressure relief valve 29, oil line connector 20, air line connector 25 and the oil-air line passage connecting the oil line connector 20 and the air line connector 25 are integrated into the design, reducing the number of parts and which is beneficial to the lightweight requirements of the engine.

[0044] Those skilled in the art will recognize that numerous variations are possible with respect to the above description, and the embodiments and figures are merely for describing one or more specific implementations.

[0045] Although exemplary embodiments of the invention have been described and illustrated, those skilled in the art will understand that various changes and substitutions can be made thereto without departing from the spirit of the invention. Furthermore, many modifications can be made to adapt specific situations to the doctrine of the invention without departing from the central concepts of the invention described herein. Therefore, the invention is not limited to the specific embodiments disclosed herein, but may include all embodiments and equivalents that fall within the scope of the invention.

Claims

1. A crankcase for an integrated air pump in a two-stroke heavy oil piston engine, comprising a crankcase, a cylinder head, and an air auxiliary nozzle assembly, wherein a crankshaft is installed inside the crankcase and the crankshaft is arranged along the front-rear direction of the crankcase; the cylinder head is respectively installed on the left and right sides of the crankcase, and the air auxiliary nozzle assembly is also installed on the cylinder head on the side opposite to the crankcase; characterized in that: It also includes an air pump assembly, which is integrated on the rear side of the crankcase. The air pump assembly includes an air compressor cylinder head, cylinder block, cylinder liner, diaphragm, spring, piston, and connecting rod. The upper part of the cylinder block is connected to and communicates with the rear side of the crankcase. The cylinder block and the air compressor cylinder head are assembled together to form a first cavity for installing the connecting rod, cylinder liner, piston, diaphragm, and spring. The cylinder liner is fixed inside the cylinder body, and the piston is installed inside it; the lower end of the connecting rod is hinged to the piston, and the upper end is connected to the rear end of the crankshaft through an eccentric component; The inner wall of the cylinder is provided with a plurality of air passages arranged along the cylinder axial direction, and the lower end of the air passages is connected to the first space formed by the lower end face of the cylinder liner and the upper side of the diaphragm; the side wall of the cylinder liner is also provided with a plurality of air holes, the positions of the air holes corresponding to the positions of the air passages. The diaphragm is installed below the cylinder liner, and its periphery is in clearance fit with the inner cavity of the air compressor cylinder head; the spring is fixed to the bottom of the inner cavity of the air compressor cylinder head, and its upper end is fixedly connected to the diaphragm.

2. The crankcase of an integrated air pump for a two-stroke heavy oil piston engine as described in claim 1, characterized in that: The eccentric component includes a boss and an eccentric shaft. The boss is a boss structure composed of two cylinders of different sizes. An axial connecting hole is provided at the rear end of the crankshaft. The small end of the boss is interference-fitted into the connecting hole. The large end of the boss is provided with the eccentric shaft. The axis of the eccentric shaft is parallel to the axis of the crankshaft.

3. The crankcase of an integrated air pump for a two-stroke heavy oil piston engine as described in claim 1, characterized in that: The gap between the diaphragm and the air compressor cylinder head is 0.1~0.2mm.

4. The crankcase of an integrated air pump for a two-stroke heavy oil piston engine as described in claim 1, characterized in that: The lower part of the cylinder liner is provided with a skirt, and the lower end of the skirt abuts against the diaphragm to separate the first space.

5. The crankcase of an integrated air pump for a two-stroke heavy oil piston engine as described in claim 1, characterized in that: The upper part of the cylinder block is provided with an extension, which extends upwards towards the cylinder block. Its front side is in contact with and sealed to the rear end face of the crankcase. An assembly groove for the connecting rod to move is opened on the front side of the extension, which extends downwards and communicates with the inside of the cylinder liner.

6. The crankcase of an integrated air pump for a two-stroke heavy oil piston engine as described in claim 5, characterized in that: The lower part of the rear end of the crankcase has a vent hole corresponding to the position of the assembly slot.

7. The crankcase of an integrated air pump for a two-stroke heavy oil piston engine as described in claim 6, characterized in that: The crankcase includes a front housing and a rear housing. When the front housing and the rear housing are combined, they form a second cavity for assembling the crankshaft. The two ends of the crankshaft are connected to the front housing and the rear housing respectively through bearings. A generator is installed at the front end of the front housing. The cylinder head is installed on the left and right sides of the rear housing, and the vent is provided at the rear end.

8. The crankcase of an integrated air pump for a two-stroke heavy oil piston engine as described in claim 7, characterized in that: The cylinder block of the air pump assembly and the rear housing are integrally cast.

9. The crankcase of an integrated air pump for a two-stroke heavy oil piston engine as described in claim 1, characterized in that: The air-assisted nozzle assembly includes an injector sleeve, a nozzle, an injector support, a pressure relief valve, an air nozzle, and a spark plug. The injector sleeve is equipped with an oil line connector to deliver fuel to the nozzle. The injector support is equipped with an air line connector, which is connected to the inside of the air compressor cylinder head via a pipeline.

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