Crankshaft arrangement and assembly method for an in-line two-cylinder air-holding direct injection engine

Abstract

The application discloses a crankshaft arrangement structure and assembling method of a straight-line double-cylinder air-entraining direct-injection engine, which comprises a crankcase assembly, a crankshaft assembly and a compressor assembly, the crankcase assembly comprises an upper crankcase body, a lower crankshaft body and a positioning pin, the upper crankcase body and the lower crankshaft body are positioned and combined by the positioning pin, a cavity is arranged on the middle side of the combined body as a cylinder body part of the compressor assembly, the crankshaft assembly comprises a crank I, a crank II, a crank III, a crank IV and a driving device eccentric shaft of the compressor, the crank I and the crank II are located in the front end of the crankcase assembly, the eccentric shaft is located in the middle end of the crankcase assembly, and the crank III and the crank IV are located in the rear end of the crankcase assembly. The crankshaft arrangement structure can shorten the crankshaft, is more compact, and can reduce the weight and the volume.

Description

TECHNICAL FIELD

[0001] The application relates to a crankshaft arrangement and an assembling method of an inline double-cylinder air-entraining direct injection engine. BACKGROUND

[0002] The air-entraining direct injection system is widely used in the field of unmanned aerial vehicle engines. The air-entraining direct injection system can realize the ignition combustion of heavy oil fuels such as aviation kerosene and diesel, avoids the low power-to-weight ratio of traditional compression ignition engines, and can meet the power-to-weight ratio requirements of current unmanned aerial vehicle engines.

[0003] The air-entraining direct injection system is a unique low-pressure air-assisted in-cylinder direct injection system, which is composed of a fuel supply system, an air supply system, a fuel injector, an air injector and the like. The system pre-mixes compressed air and fuel, and then injects the oil-gas mixture into the cylinder at high speed through a direct injection nozzle, atomizes the fuel into extremely fine droplets at high speed and evaporates rapidly. On the one hand, the requirement of the engine for the fuel system is greatly reduced, and on the other hand, the spray diffusion and mixing process is more rapid. The air supply system is used to provide a certain pressure and pure compressed air to the air-assisted fuel injector for fuel assisted atomization.

[0004] At present, the air-entraining direct injection technology is used for oil supply of an inline double-cylinder engine. The air supply system mainly adopts the method of carrying an external air pump to improve the fuel atomization quality by increasing the pressure, improve the engine power, and significantly improve the fuel economy. The air-entraining direct injection technology adopts a chain or a belt to indirectly drive the air compressor to work, realizes the unification of air supply and phase, but this structure not only increases the overall size and weight of the engine, but also reduces the engine power. It cannot meet the requirements of high power-to-weight ratio of unmanned aerial vehicle engines. SUMMARY

[0005] The application aims to provide a compact inline double-cylinder air-entraining direct injection engine crankshaft arrangement and an assembling method.

[0006] In order to achieve the above-mentioned purpose, the application is realized as follows: a crankshaft arrangement structure and assembling method of an inline double-cylinder air-injected direct injection engine, comprising a crankcase assembly, a crankshaft assembly and a compressor assembly, characterized in that: the crankcase assembly comprises an upper crankcase body and a lower crankcase body and a positioning pin, the upper crankcase body and the lower crankcase body are positioned and combined by the positioning pin, the upper crankcase body and the lower crankcase body are provided with cavities in the middle side of the combined body as the cylinder body part of the compressor assembly, the crankshaft assembly comprises a crank one, a crank two, a crank three, a crank four and a driving device eccentric shaft of the compressor, the crank one and the crank two are located in the front end of the crankcase assembly, the eccentric shaft is located in the middle end of the crankcase assembly, the crank three and the crank four are located in the rear end of the crankcase; the compressor assembly comprises a compressor connecting rod, a pin, a piston and an air filter, the air filter is arranged on the other side of the piston and is horizontal to the piston, the compressor connecting rod is assembled on the eccentric shaft through interference pressing of a roller bearing, and the piston is connected with the connecting rod through the pin to form an air pump driven by the eccentric shaft.

[0007] Preferably, the eccentric shaft is arranged at the L / 2 position in the middle of the crankshaft assembly and is interference-pressed on the crank two and the crank three.

[0008] Preferably, the upper crankcase body is provided with a glue coating groove.

[0009] Preferably, the upper crankcase is provided with a lubricating hole, which aims to further solve the problems of compressor connecting rod lubrication and engine blending burning.

[0010] In order to further improve the lubricating effect of the big end of the connecting rod in the crankcase, the upper crankcase body is provided with a lubricating hole on the air inlet side.

[0011] In addition, an assembling method of an inline double-cylinder air-injected direct injection engine is provided, comprising the crankshaft arrangement structure, characterized in that: the following steps are performed in sequence:

[0012] (1) interference-pressing the crank one and the crank two, and interference-pressing the crank three and the crank four;

[0013] (2) hot-assembly of deep groove ball bearing one on the crank one, hot-assembly of deep groove ball bearing two on the crank two, hot-assembly of deep groove ball bearing two on the crank three, hot-assembly of deep groove ball bearing two on the crank four, and hot-assembly of deep groove ball bearing one on the long shaft end of the crank four;

[0014] (3) interference-pressing the eccentric shaft on the crank three at the phase (60°-120°) and the L / 2 axial position, and then gap assembling the big end of the compressor connecting rod with the interference-pressed big head roller bearing on the eccentric shaft bearing seat end;

[0015] (4) interference-pressing the other end of the eccentric shaft on the crank two, and finally combining the upper crankcase body and the lower crankcase body.

[0016] Advantages:

[0017] The crankshaft arrangement structure and assembly method of the in-line double-cylinder air-entraining direct injection engine has the following innovations:

[0018] The in-line double-cylinder engine is combined with the air compressor to realize the integration of the air compressor compression air supply and the in-line double-cylinder engine, so that the structure is compact.

[0019] The crankshaft arrangement structure and assembly method of the in-line double-cylinder air-entraining direct injection engine has the following innovations:

[0020] 1) The eccentric shaft is arranged in the middle of the crankshaft, and the air compressor is driven by the rotation of the crankshaft, which significantly improves the stability of the air compressor.

[0021] 2) The upper and lower crankcases are combined, and the structure of the glue groove is added, which greatly improves the sealing performance of the crankcase.

[0022] 3) The air compressor intake passage arranged in the upper crankcase is horizontal to the air compressor, which shortens the intake distance and increases the intake smoothness, so that the air supply of the air compressor is more stable.

[0023] 4) The air inlet side supplementary lubricating oil hole is adopted, and the lubrication is realized by the rotation of the crank. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 It is a front view of the arrangement form of the crankshaft in the strength;

[0025] In the figure:

[0026] 11 - upper crankcase 13 - positioning pin 21 - crank one

[0027] 22 - crank two 23 - eccentric shaft 24 - crank three

[0028] 25 - crank four 26 - deep groove ball bearing 27 - deep groove ball bearing

[0029] 31 - air filter 32 - air compressor connecting rod 33 - pin

[0030] 34 - piston 2 - crankshaft assembly 3 - air compressor assembly

[0031] Figure 2 It is a glue groove distribution diagram of the upper crankcase;

[0032] Figure 3 It is a partial view of the eccentric shaft;

[0033] Figure 4 It is a phase diagram of the eccentric shaft;

[0034] Figure 5 is a structure diagram of a crankcase;

[0035] Figure 6 is a lubrication route diagram of a compressor;

[0036] in the figure:

[0037] 11 - upper crankcase 1 - crankcase assembly 12 - lower crankcase DETAILED DESCRIPTION

[0038] The present application is further described below in conjunction with the accompanying drawings and examples.

[0039] The basic idea of the present application is to integrate a gas direct injection engine with a compressor on a straight double-cylinder engine, make full use of the space structure, make the engine more compact, and at the same time, be able to provide a stable source of air.

[0040] Embodiment: as shown in the figure provides a compact and stable straight double-cylinder gas direct injection engine crank arrangement structure. Figures 1-6

[0041] Wherein, the crankcase assembly 1 includes an upper crankcase 11 and a lower crankcase 12 and a positioning pin 12, the upper crankcase 11 and the lower crankcase 12 are positioned by the positioning pin 13, the upper crankcase 11 and the lower crankcase 12 are provided with a cavity in the middle side of the joint body as the cylinder part of the compressor assembly 3, the crank assembly 2 includes crank one 21, crank two 22, crank three 24, crank four 25 and the driving device eccentric shaft 23 of the compressor, the crank one 21 and the crank two 22 are located in the front end of the crankcase assembly 1, the eccentric shaft 23 is located in the middle end of the crankcase assembly 1, the crank three 24 and the crank four 25 are located in the rear end of the crankcase 1; The compressor assembly 3 includes a compressor connecting rod 32, a pin 33, a piston 34, an air filter 31, the air filter 31 is arranged on the other side of the piston 34 and is horizontal with the piston 34, the compressor connecting rod 32 is assembled by interference needle bearing and then mounted on the eccentric shaft 23, the piston 34 forms a gas pump driven by the eccentric shaft 23 through the pin 33 and the compressor connecting rod 32.

[0042] In this example, the upper crankcase 11 is provided with a glue groove, and Loctite flat sealant is used for coating. After the joint bolt is tightened, the sealant will overflow to the plane, achieving the effect of strengthening the sealing ability.

[0043] ​In the present example, the bearings used are self-lubricating two-sided closed deep groove ball bearings, the main advantages of which are that they do not need to consume two-stroke mixed oil for lubrication, and that the bearings are sealed, which can perfectly separate the double cylinder and the compressor, and no sealing measures need to be added on the small displacement engine. At the same time, the inner ring is hot-mounted, the outer ring is interference-mounted, and the Loctite plane sealant is coated, so that the crankshaft assembly is stably mounted, and the interference amount will not be too large to separate the case.

[0044] In the present example, the eccentric shaft 23 is located at the L / 2 assembly position, and a lubricating hole is provided on the upper crankcase 11, so that the lubricating oil drops on the compressor connecting rod 32, and splash lubrication is achieved as the eccentric shaft 23 rotates.

[0045] Similarly, the lubricating hole provided on the air inlet is splash lubricated as the crank rotates.

[0046] In addition, the present example also provides an assembly method of the in-line double-cylinder air-entraining direct injection engine, comprising the above-mentioned crank arrangement structure, characterized in that the following steps are installed in the following order:

[0047] (1) press-fit the crank one 21 and the crank two 22, and press-fit the crank three 24 and the crank four 25;

[0048] (2) hot-mount the deep groove ball bearing one 26 on the crank one 21, hot-mount the deep groove ball bearing two 27 on the crank two 22, hot-mount the deep groove ball bearing two 27 on the crank three 24, hot-mount the deep groove ball bearing two 27 on the crank four 25, and hot-mount the deep groove ball bearing one 26 on the long shaft end of the crank four 25;

[0049] (3) press-fit the eccentric shaft 23 on the crank three 24 in the phase (60°-120°) and the axial position L / 2 by interference, and then assemble the large end gap of the compressor connecting rod 32 with the large-end press-fit roller bearing on the bearing seat end of the eccentric shaft 23;

[0050] (4) press-fit the other end of the eccentric shaft 23 on the crank two 22, and finally assemble the upper crankcase 11 and the lower crankcase 12.

[0051] Further, the arrangement form and method of the present example are used:

[0052] The crank arrangement structure and assembly method of the in-line double-cylinder air-entraining direct injection engine of the present application have the following innovative points:

[0053] The in-line double-cylinder engine is combined with the compressor to realize the integration of the compressor compression air supply and the in-line engine, so that the structure is compact.

[0054] The crank arrangement structure and assembly method of the in-line double-cylinder air-entraining direct injection engine of the present application have the following significant advantages.

[0055] 1、The eccentric shaft 23 is arranged in the middle of the crankshaft assembly, and the compressor is driven by the rotation of the crankshaft, which significantly improves the stability of the compressor.

[0056] 2、The upper and lower crankcase bodies are combined, and the structure of the glue groove is matched, which greatly improves the sealing performance of the crankcase.

[0057] 3、The compressor intake passage arranged in the upper crankcase body 11 is horizontal with the compressor, which shortens the intake distance, increases the intake smoothness, and makes the compressor gas supply more stable.

[0058] 4、The intake port side supplementary lubricating oil hole is used for splashing lubrication by the rotation of the crank.

Claims

1. A crankshaft arrangement for an in-line two-cylinder air-entrained direct injection engine, comprising a crankcase assembly (1), a crankshaft assembly (2) and a compressor assembly (3), characterised in that: The crankcase assembly (1) comprises an upper crankcase (11) and a lower crankcase (12) and a positioning pin (13), the upper crankcase (11) and the lower crankcase (12) are positioned and closed by the positioning pin (13), the upper crankcase (11) and the lower crankcase (12) are provided with cavities as cylinder parts of the compressor assembly (3) on the middle side of the closed body, the crank assembly (2) comprises crank one (21), crank two (22), crank three (24), crank four (25) and the driving device eccentric shaft (23) of the compressor, the crank one (21) and the crank two (22) are located in the front end of the crankcase assembly (1), the eccentric shaft (23) is located in the middle end of the crankcase assembly (1), the crank three (24) and the crank four (25) are located in the rear end of the crankcase assembly (1); the compressor assembly (3) comprises a compressor connecting rod (32), a pin (33), a piston (34), and an air filter (31), the air filter (31) is arranged on the other side of the piston (34) and is horizontal with the piston (34), the compressor connecting rod (32) is assembled by interference needle bearing and is assembled on the eccentric shaft (23), the piston (34) forms a gas pump driven by the eccentric shaft (23) with the compressor connecting rod (32) through the pin (33).

2. A crankshaft arrangement for an inline two-cylinder air- trapped direct injection engine according to claim 1, characterized in that: The upper crankcase (11) is provided with a glue groove on the contact end face.

3. A crankshaft arrangement for an inline two-cylinder air- trapped direct injection engine according to claim 1, characterized in that: The upper crankcase (11) is provided with lubricating holes.

4. A crankshaft arrangement for an inline two-cylinder air- trapped direct injection engine according to claim 3, characterized in that: The lubricating holes are three, one of which is located in the middle of the upper end of the upper crankcase (11), and the other two are located on the upper end of the side air inlet of the upper crankcase (11).

5. A crankshaft arrangement for an inline two-cylinder air- trapped direct injection engine according to claim 1, characterized in that: The pump side and the air inlet side of the compressor are horizontally opposite in the same plane.

6. A method of assembling a crankshaft arrangement of an inline twin-cylinder air- trapped direct injection engine according to claim 1, characterized in that: The following steps are in the following order: (1) Assembling the crank one (21) and the crank two (22), assembling the crank three (24) and the crank four (25); (2) Hot assembling deep groove ball bearing one (26) on the crank one (21), hot assembling deep groove ball bearing two (27) on the crank two (22), hot assembling deep groove ball bearing two (27) on the crank three (24), hot assembling deep groove ball bearing two (27) on the crank four (25), and hot assembling deep groove ball bearing one (26) on the long end of the crank four (25); (3) Assembling the eccentric shaft (23) on the crank three (24) by interference pressing at a phase of 60°-120° and an axial position of L / 2, and then assembling the large end gap of the compressor connecting rod (32) with the large head needle bearing on the eccentric shaft bearing seat end; (4) Pressing the other end of the eccentric shaft (23) on the crank two (22), and finally closing the upper crankcase (11) and the lower crankcase (12).

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