Engine gear transmission system and assembly method

Abstract

This invention belongs to the field of vehicle technology and discloses an engine gear transmission system and assembly method. The air compressor gear and the high-pressure oil pump gear are both driven to rotate by the intermediate gear. The knocking force between the meshing gears under different phase interval angles is calculated through simulation. Then, based on the knocking force, the intersection of the phase interval angle range where the knocking noise of the high-pressure oil pump and air compressor gears is relatively small is selected. Through experiments, it was found that the engine noise is significantly improved when operating at low and medium speeds. The engine noise is improved by more than 1.0 dBA under idling conditions, and the contribution of air compressor pumping noise is reduced by 0.5 dBA, thereby effectively improving the consistency between different engines during engine production.

Description

Technical Field

[0001] This invention relates to the field of engine technology, and in particular to an engine gear transmission system and assembly method. Background Technology

[0002] During the operation of the engine gear transmission system, the high-pressure oil pump gear, air compressor gear, and crankshaft gear all have negative torque, which causes knocking noise between the meshing gears.

[0003] Existing technologies often reduce knocking noise by controlling the backlash of the shearing gear. However, the shearing gear consists of a driven gear and a secondary gear, connected by a flexible component such as rubber or an Ω spring surrounding a cylindrical pin. This method reduces the reliability of the gear transmission and easily causes noise problems such as gear squealing. Furthermore, the use of shearing gears increases the cost of the gear transmission system. Summary of the Invention

[0004] The purpose of this invention is to provide an engine gear transmission system and assembly method that can reduce noise problems such as knocking noise and gear howling in gear transmission.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] The assembly method for an engine gear transmission system includes the following steps:

[0007] The crankshaft gear is assembled onto the crankshaft, and the crankshaft is rotated to bring the piston of the target cylinder to the top dead center of the compression of the target cylinder.

[0008] Assemble the intermediate gear onto the intermediate gear shaft;

[0009] Determine a first preset angle, and determine the difference between the target phase interval angle and the first preset angle as a second preset angle;

[0010] Control the high-pressure oil pump to run to a position at a first preset angle before the lower dead center of the high-pressure oil pump, and assemble the high-pressure oil pump gear to the oil pump gear shaft; control the air compressor to move to a position at a second preset angle after the upper dead center of the air compressor, and assemble the air compressor gear to the air compressor shaft;

[0011] The target phase interval angle is obtained according to the following steps:

[0012] A dynamic model of the engine gear transmission system is established, and the top dead center of the air compressor is set after the bottom dead center of the high-pressure oil pump, and the phase interval angle between the top dead center of the air compressor and the bottom dead center of the high-pressure oil pump is i.

[0013] The total chain force of the high-pressure oil pump and the total chain force of the air compressor are calculated by simulation under different phase interval angles i; i takes a value in the range of 0°-180°, and the interval between two adjacent phase interval angles i is j, j=360 / Z, where Z is the number of teeth of the air compressor gear;

[0014] Determine the first phase interval angle range that differs from the minimum total chain force of the high-pressure oil pump by a preset total chain force, and the second phase interval angle range that differs from the minimum total chain force of the air compressor by a preset total chain force;

[0015] Determine the intersection of the phase interval angle ranges of the first phase interval angle range and the second phase interval angle range;

[0016] The target phase interval angle is selected from the intersection of the phase interval angle ranges.

[0017] As one possible implementation of the above-mentioned engine gear transmission system assembly method, the average of the maximum and minimum values ​​of the intersection of the phase interval angle ranges is selected as the target phase interval angle.

[0018] As one possible implementation of the above-mentioned engine gear transmission system assembly method, the first preset angle is 18° and the second preset angle is 102°.

[0019] To achieve the above objectives, the present invention also provides an engine gear transmission system, which adopts the engine gear transmission system assembly method described in any of the above schemes. The engine gear transmission system includes an intermediate gear, and crankshaft gears, air compressor gears, and high-pressure oil pump gears that are circumferentially spaced around the intermediate gear and mesh with the intermediate gear.

[0020] As one possible implementation of the aforementioned engine gear transmission system, one of the high-pressure oil pump gear and the intermediate gear is provided with two first phase marking teeth, and the two first phase marking teeth are two adjacent teeth on the gear, while the other is provided with a second phase marking tooth; when the piston of the target cylinder reaches the top dead center of compression, the second phase marking tooth meshes with the two first phase marking teeth.

[0021] As one possible implementation of the above-mentioned engine gear transmission system, the oil pump flange of the high-pressure oil pump is provided with an oil pump flange mark, and the high-pressure oil pump gear is provided with an oil pump gear mark;

[0022] When the oil pump flange mark and the oil pump gear mark are aligned, the high-pressure oil pump is at a first preset angle before the bottom dead center of the high-pressure oil pump.

[0023] As one possible implementation of the above-mentioned engine gear transmission system, the crankshaft gear is provided with a timing mark, and the intermediate gear is provided with an intermediate gear phase mark;

[0024] When the piston of the target cylinder reaches the top dead center of the compression stroke, the timing mark is aligned with the phase mark of the intermediate gear.

[0025] As one possible implementation of the above-mentioned engine gear transmission system, one of the air compressor gear and the intermediate gear is provided with two first marking teeth, and the two first marking teeth are two adjacent teeth on the gear, while the other is provided with a second marking tooth.

[0026] When the piston of the target cylinder reaches the top dead center of compression, the second marking tooth engages with the two first marking teeth.

[0027] As one possible implementation of the above-mentioned engine gear transmission system, a crankshaft phase mark is provided on the crankshaft, and an air compressor cylinder phase mark is provided on the air compressor cylinder block.

[0028] When the crankshaft phase mark is located between the two air compressor cylinder phase marks along the circumference of the crankshaft, the air compressor is at a second preset angle after the top dead center of the air compressor.

[0029] As one possible implementation of the aforementioned engine gear transmission system, the air compressor cylinder is provided with a bearing housing, the bearing housing is provided with an upper limit mark and a lower limit mark, and along the circumference of the bearing housing, the air compressor cylinder phase mark is provided between the upper limit mark and the lower limit mark;

[0030] The crankshaft phase mark is located between the upper limit mark and the lower limit mark along the circumference of the crankshaft, and the air compressor is at a second preset angle after the top dead center of the air compressor.

[0031] The beneficial effects of this invention are as follows: The engine gear transmission system and assembly method provided by this invention are both driven to rotate by the intermediate gear, and the air compressor gear and the high-pressure oil pump gear are driven to rotate by the intermediate gear. The knocking force between the meshing gears under different phase interval angles is calculated by simulation. Then, according to the magnitude of the knocking force, the intersection of the phase interval angle range where the knocking noise of the high-pressure oil pump and the air compressor gears is relatively small is selected. Through experiments, it was found that the engine noise is significantly improved when operating at low and medium speeds. The engine noise is improved by more than 1.0 dBA under idling conditions, and the contribution of air compressor pumping noise is reduced by 0.5 dBA, thereby effectively improving the consistency between different engines during engine production. Attached Figure Description

[0032] Figure 1This is a schematic diagram of the engine gear rotation system provided in an embodiment of the present invention;

[0033] Figure 2 This is a flowchart of the assembly method for the engine gear rotation system provided in an embodiment of the present invention;

[0034] Figure 3 This is a graph showing the relationship between the total chain force of the high-pressure oil pump, the total chain force of the air compressor, and the phase interval angle, obtained through simulation calculations.

[0035] Figure 4 This is a schematic diagram of the high-pressure oil pump provided in an embodiment of the present invention;

[0036] Figure 5 This is a schematic diagram of an air compressor provided in an embodiment of the present invention.

[0037] In the picture:

[0038] 1. Crankshaft gear; 2. Intermediate gear; 3. Air compressor gear; 4. High-pressure oil pump gear; 5. Top dead center timing position; 6. Timing mark; 7. Intermediate gear phase mark; 8. Second phase mark tooth; 9. First phase mark tooth; 10. Second mark tooth; 11. First mark tooth;

[0039] 12. Oil pump flange markings; 13. Oil pump gear markings;

[0040] 14. Crankshaft phase mark; 15. Air compressor cylinder phase mark; 16. Upper limit mark; 17. Lower limit mark. Detailed Implementation

[0041] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0042] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0043] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0044] In the description of this embodiment, the terms "upper," "lower," "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0045] like Figure 1 As shown, an embodiment of the present invention provides an engine gear transmission system, including an intermediate gear 2, and crankshaft gear 1, air compressor gear 3 and high-pressure oil pump gear 4, which are circumferentially spaced around the intermediate gear 2 and mesh with the intermediate gear 2.

[0046] Crankshaft gear 1 is connected to the crankshaft. When the crankshaft rotates, crankshaft gear 1 drives intermediate gear 2 to rotate. Intermediate gear 2 drives air compressor gear 3 and high-pressure oil pump gear 4 to rotate. The speed ratio of air compressor gear 3 and high-pressure oil pump gear 4 is 1:1 or 0.5:1.

[0047] like Figure 2 As shown, an embodiment of the present invention also provides an engine gear transmission system assembly method for the aforementioned engine gear transmission system. The engine gear transmission system assembly method includes the following steps:

[0048] S1. Assemble crankshaft gear 1 onto crankshaft, and rotate crankshaft to make the piston of target cylinder run to the top dead center timing position 5 of the compression of target cylinder;

[0049] S2. Assemble intermediate gear 2 to the intermediate gear shaft;

[0050] S3. Determine the first preset angle, and determine the difference between the target phase interval angle and the first preset angle as the second preset angle;

[0051] S4. Control the high-pressure oil pump to run to a position at the first preset angle before the lower dead center of the high-pressure oil pump, and assemble the high-pressure oil pump gear 4 to the oil pump gear shaft; control the air compressor to move to a position at the second preset angle after the upper dead center of the air compressor, and assemble the air compressor gear 3 to the air compressor shaft.

[0052] The target phase interval angle is obtained according to the following steps:

[0053] A dynamic model of the engine gear transmission system is established, and the top dead center of the air compressor is set to be after the bottom dead center of the high-pressure oil pump, and the phase interval angle between the top dead center of the air compressor and the bottom dead center of the high-pressure oil pump is set to i.

[0054] The total chain force of the high-pressure oil pump and the total chain force of the air compressor are calculated by simulation under different phase interval angles i; i takes a value in the range of 0°-180°, and the interval j between two adjacent phase interval angles i is j=360 / Z, where Z is the number of teeth of gear 3 of the air compressor.

[0055] Determine the first phase interval angle range that differs from the minimum total chain force of the high-pressure oil pump by a preset total chain force, and the second phase interval angle range that differs from the minimum total chain force of the air compressor by a preset total chain force;

[0056] Determine the intersection of the phase interval angle ranges of the first phase interval angle range and the second phase interval angle range;

[0057] Select one of the values ​​within the intersection of the phase interval angle ranges as the target phase interval angle.

[0058] The total chain force of the high-pressure oil pump refers to the resultant force of the impact force between the high-pressure oil pump gear 4 and the intermediate gear 2 caused by the negative torque of the high-pressure oil pump, as well as the impact force between the intermediate gear 2 and the crankshaft gear 1. The total chain force of the air compressor refers to the resultant force of the impact force between the air compressor gear 3 and the intermediate gear 2 caused by the negative torque of the air compressor, as well as the impact force between the intermediate gear 2 and the crankshaft gear 1.

[0059] It should be noted that how to calculate the impact force between meshing gears is existing technology in this field and will not be described in detail here.

[0060] The gear knocking noise caused by the negative torque of the air compressor varies greatly when the engine is idling or running at low speed, and when the air compressor is switching from not working to working. The gear knocking noise when the air compressor is working is unpleasant. Therefore, when selecting the phase interval difference between the high-pressure oil pump gear 4 and the air compressor gear 3, it is necessary to first ensure that the knocking force of the air compressor gear 3 is small, and on this basis, ensure that the knocking force of the high-pressure oil pump gear 4 is small.

[0061] Figure 3This is a graph showing the relationship between the total chain force of the high-pressure oil pump, the total chain force of the air compressor, and the phase interval angle, obtained through simulation calculations. Figure 3 The total chain force of the high-pressure oil pump is relatively small within the phase interval angle range of 100°-130°. Figure 3 The total chain force of the air compressor is relatively small within the phase interval angle range of 110°-160°. Taking the intersection of the phase interval angles of 100°-130° and 110°-160°, we get the phase interval angle range of 110°-130°. Therefore, when the phase interval angle between the high-pressure oil pump gear 4 and the air compressor gear 3 is within this range, the gear knocking noise is relatively small.

[0062] Both the air compressor gear 3 and the high-pressure oil pump gear 4 are driven to rotate by the intermediate gear 2. The knocking force between the meshing gears under different phase interval angles is calculated through simulation. Then, based on the magnitude of the knocking force, the intersection of the phase interval angle range where the knocking noise of the high-pressure oil pump and air compressor gears is relatively small is selected. Through experiments, it was found that the engine noise is significantly improved when operating at low and medium speeds. The engine noise is improved by more than 1.0 dBA at idle, and the contribution of air compressor pumping noise is reduced by 0.5 dBA. This can effectively improve the knocking "ticking" sound and reduce engine noise. At the same time, the consistency between different engines during high-volume production is beneficial to improving product consistency.

[0063] In some embodiments, the average of the maximum and minimum values ​​of the intersection of the phase interval angle ranges is selected as the target phase interval angle. This avoids the influence of factors such as manufacturing errors and installation errors. For example, the target phase interval angle is 120°. It should be noted that the target phase interval angle can also be selected from any one of 115°, 116°, 117°, 118°, 119°, 121°, 122°, 123°, 124°, and 125°.

[0064] In some embodiments, the engine is a multi-cylinder engine, the target cylinder is cylinder one of the engines, which is the first cylinder at the front of the engine, and the operation of other cylinders is referenced to cylinder one of the engines.

[0065] In some embodiments, the first preset angle is 18° and the second preset angle is 102°.

[0066] Based on the principle of minimum rail pressure for the high-pressure fuel pump, 18° before the bottom dead center of the high-pressure fuel pump is the top dead center of the compression stroke of cylinder one of the engines; that is, the first preset angle is 18°. It should be noted that the first preset angle is related to the fuel system of the high-pressure fuel pump and is not a fixed value. Once the first preset angle is determined, the specific angle of the second preset angle can be determined based on the target phase interval angle.

[0067] In some embodiments, of the high-pressure oil pump gear 4 and the intermediate gear 2, one is provided with two first phase marking teeth 9, and the two first phase marking teeth 9 are two adjacent teeth on the gear, and the other is provided with a second phase marking tooth 8; when the piston of the target cylinder runs to the compression top dead center timing position 5, the second phase marking tooth 8 meshes with the two first phase marking teeth 9.

[0068] When assembling the engine gear transmission system, under the premise that the piston of the target cylinder is rotated to the top dead center timing position 5 of the target cylinder, when assembling the high-pressure oil pump gear 4, the second phase marking tooth 8 is engaged with the two first phase marking teeth 9, so as to determine the phase relationship between the high-pressure oil pump gear 4 and the intermediate gear 2, thereby determining the phase relationship between the high-pressure oil pump gear 4 and the crankshaft gear 1.

[0069] For example, the high-pressure oil pump gear 4 is provided with two first phase marking teeth 9, and the intermediate gear 2 is provided with a second phase marking tooth 8. When the second phase marking tooth 8 and the two first phase marking teeth 9 mesh, the meshing position of the second phase marking tooth 8 and the two first phase marking teeth 9 is 18° before the compressor's lower limit point.

[0070] In some embodiments, such as Figure 1 As shown, a timing mark 6 is provided on the crankshaft gear 1, and an intermediate gear phase mark 7 is provided on the intermediate gear 2; when the piston of the target cylinder reaches the top dead center timing position 5 of the compression stroke, the timing mark 6 and the intermediate gear phase mark 7 are aligned. When assembling the engine gear transmission system, the timing mark 6 and the intermediate gear phase mark 7 can be used to determine the phase relationship between the high-pressure oil pump gear 4 and the crankshaft gear 1.

[0071] In some embodiments, such as Figure 1 As shown, of the air compressor gear 3 and the intermediate gear 2, one is provided with two first marking teeth 11, and the two first marking teeth 11 are two adjacent teeth on the gear. The other is provided with a second marking tooth 10. When the piston of the target cylinder runs to the compression top dead center timing position 5, the second marking tooth 10 meshes with the two first marking teeth 11.

[0072] For example, the air compressor gear 3 is provided with two first marking teeth 11, and the intermediate gear 2 is provided with a second marking tooth 10.

[0073] When assembling the engine gear transmission system, under the premise that the piston of the target cylinder is rotated to the top dead center timing position 5 of the target cylinder, the second marking tooth 10 is made to mesh with the two first marking teeth 11 when assembling the air compressor gear 3, so as to determine the phase relationship between the air compressor gear 3 and the intermediate gear 2, thereby determining the phase relationship between the air compressor gear 3 and the crankshaft gear 1.

[0074] In some embodiments, such as Figure 4 As shown, the oil pump flange of the high-pressure oil pump is marked with oil pump flange 12, and the oil pump gear 4 is marked with oil pump gear 13; when the oil pump flange mark 12 and the oil pump gear mark 13 are aligned, the high-pressure oil pump is at the first preset angle before the bottom dead center of the high-pressure oil pump.

[0075] When repairing and installing the high-pressure oil pump, align the oil pump gear mark 13 and the oil pump flange mark 12, then rotate the engine to the top dead center timing position 5 of the first cylinder of the engine, and then fix the high-pressure oil pump.

[0076] When replacing the high-pressure oil pump later, the first phase marking tooth 9 and the second phase marking tooth 8 cannot be seen without removing the cover plate of the gear chamber. When replacing the high-pressure oil pump, when the piston of the target cylinder reaches the compression top dead center timing position 5, the oil pump flange marking 12 and the oil pump gear marking 13 are aligned, which can make the high-pressure oil pump assembled in the correct position and improve the convenience of replacing the high-pressure oil pump.

[0077] The assembly process of the high-pressure oil pump during maintenance is as follows:

[0078] S21. Align the oil pump flange mark 12 and the oil pump gear mark 13 so that the high-pressure oil pump is 18° before the bottom dead center of the high-pressure oil pump.

[0079] S22. Check if the oil pump flange mark 12 and the oil pump gear mark 13 are aligned. If yes, proceed to S23; otherwise, return to S21.

[0080] S23, rotate the engine to the top dead center of the compression stroke of cylinder one;

[0081] S24, Fixed high-pressure oil pump.

[0082] In some embodiments, such as Figure 5 As shown, a crankshaft phase mark 14 is provided on the crankshaft, and an air compressor cylinder phase mark 15 is provided on the air compressor cylinder block; when the crankshaft phase mark 14 is located between the two air compressor cylinder phase marks 15 along the circumference of the crankshaft, the air compressor is at the second preset angle after the air compressor top dead center.

[0083] The air compressor cylinder is provided with a bearing housing, and the bearing housing is provided with an upper limit mark 16 and a lower limit mark 17. Along the circumference of the bearing housing, the air compressor cylinder phase mark 15 is located between the upper limit mark 16 and the lower limit mark 17. When the crankshaft phase mark 14 is located between the upper limit mark 16 and the lower limit mark 17 along the circumference of the crankshaft, the air compressor is at the second preset angle after the top dead center of the air compressor.

[0084] When replacing the air compressor later, the second marking tooth 10 and the two first marking teeth 11 are not visible without removing the gear chamber cover. During subsequent disassembly and maintenance of the air compressor, first position the crankshaft phase mark 14 circumferentially between the two air compressor cylinder phase marks 15. Then, rotate the engine to the top dead center timing position of the compressor in cylinder one. Afterward, fix the air compressor to ensure the assembly error meets requirements. After the air compressor is assembled, determine if the air compressor phase assembly meets requirements by checking if the crankshaft phase mark 14 circumferentially lies between the upper limit mark 16 and the lower limit mark 17. When the crankshaft phase mark 14 circumferentially lies between the upper limit mark 16 and the lower limit mark 17, the air compressor phase assembly is considered to meet requirements, and the air compressor installation is complete.

[0085] The assembly process for the air compressor during maintenance is as follows:

[0086] S31. Set the crankshaft phase mark 14 along the circumference of the crankshaft between the two air compressor cylinder phase marks 15, so that the air compressor is 102° after the bottom dead center of the air compressor.

[0087] S32. Check whether the crankshaft phase mark 14 is located between the two air compressor cylinder phase marks 15 along the circumference of the crankshaft. If yes, execute S33; otherwise, return to S31.

[0088] S33, rotate the engine to the top dead center of the compression stroke of cylinder one;

[0089] S34, Stationary air compressor;

[0090] S35. After assembly, check whether the crankshaft phase mark 14 is located between the upper limit mark 16 and the lower limit mark 17 along the circumference of the crankshaft; if yes, the air compressor assembly is complete; if no, return to S31.

[0091] It should be noted that the various markings and compression top dead center timing position 5 mentioned above can be any of the following: label, boss, groove, or scribing. Marking teeth refer to teeth on gears that are provided with any of the following: label, boss, groove, or scribing. This is not specifically limited here.

[0092] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. An assembly method for an engine gear transmission system, characterized in that, Includes the following steps: The crankshaft gear (1) is assembled onto the crankshaft, and the crankshaft is rotated to make the piston of the target cylinder run to the compression top dead center timing position (5) of the target cylinder. Assemble the intermediate gear (2) onto the intermediate gear shaft; Determine a first preset angle, and determine the difference between the target phase interval angle and the first preset angle as a second preset angle; Control the high-pressure oil pump to run to a position at a first preset angle before the lower dead center of the high-pressure oil pump, and assemble the high-pressure oil pump gear (4) to the oil pump gear shaft; control the air compressor to move to a position at a second preset angle after the upper dead center of the air compressor, and assemble the air compressor gear (3) to the air compressor shaft; The target phase interval angle is obtained according to the following steps: A dynamic model of the engine gear transmission system is established, and the top dead center of the air compressor is set after the bottom dead center of the high-pressure oil pump, and the phase interval angle between the top dead center of the air compressor and the bottom dead center of the high-pressure oil pump is i. The total chain force of the high-pressure oil pump and the total chain force of the air compressor are calculated by simulation under different phase interval angles i; i takes a value in the range of 0°-180°, and the interval between two adjacent phase interval angles i is j, j=360 / Z, where Z is the number of teeth of the air compressor gear (3); The total chain force of the high-pressure oil pump refers to the resultant force of the impact force between the high-pressure oil pump gear (4) and the intermediate gear (2) caused by the negative torque of the high-pressure oil pump, and the impact force between the intermediate gear (2) and the crankshaft gear (1); the total chain force of the air compressor refers to the resultant force of the impact force between the air compressor gear (3) and the intermediate gear (2) caused by the negative torque of the air compressor, and the impact force between the intermediate gear (2) and the crankshaft gear (1); Determine the first phase interval angle range that differs from the minimum total chain force of the high-pressure oil pump by a preset total chain force, and the second phase interval angle range that differs from the minimum total chain force of the air compressor by a preset total chain force; Determine the intersection of the phase interval angle ranges of the first phase interval angle range and the second phase interval angle range; The target phase interval angle is selected from the intersection of the phase interval angle ranges.

2. The assembly method for an engine gear transmission system according to claim 1, characterized in that, The average of the maximum and minimum values ​​of the intersection of the phase interval angle ranges is selected as the target phase interval angle.

3. The assembly method for the engine gear transmission system according to claim 1, characterized in that, The first preset angle is 18°, and the second preset angle is 102°.

4. An engine gear transmission system, characterized in that, The engine gear transmission system assembly method according to any one of claims 1 to 3 includes an intermediate gear (2), and crankshaft gears (1), air compressor gears (3) and high-pressure oil pump gears (4) that are circumferentially distributed around the intermediate gear (2) and mesh with the intermediate gear (2).

5. The engine gear transmission system according to claim 4, characterized in that, Of the high-pressure oil pump gear (4) and the intermediate gear (2), one is provided with two first phase marking teeth (9) and the two first phase marking teeth (9) are two adjacent teeth on the gear, and the other is provided with a second phase marking tooth (8); when the piston of the target cylinder runs to the compression top dead center timing position (5), the second phase marking tooth (8) meshes with the two first phase marking teeth (9).

6. The engine gear transmission system according to claim 5, characterized in that, The high-pressure oil pump has an oil pump flange mark (12) on its oil pump flange and an oil pump gear mark (13) on its high-pressure oil pump gear (4). When the oil pump flange mark (12) and the oil pump gear mark (13) are aligned, the high-pressure oil pump is at a first preset angle before the bottom dead center of the high-pressure oil pump.

7. The engine gear transmission system according to claim 4, characterized in that, The crankshaft gear (1) is provided with a timing mark (6), and the intermediate gear (2) is provided with an intermediate gear phase mark (7). When the piston of the target cylinder reaches the top dead center of compression (5), the timing mark (6) is aligned with the phase mark (7) of the intermediate gear.

8. The engine gear transmission system according to claim 4, characterized in that, Of the air compressor gear (3) and the intermediate gear (2), one is provided with two first marking teeth (11) and the two first marking teeth (11) are two adjacent teeth on the gear, and the other is provided with a second marking tooth (10). When the piston of the target cylinder reaches the top dead center (5) of the compression cycle, the second marking tooth (10) engages with the two first marking teeth (11).

9. The engine gear transmission system according to claim 8, characterized in that, The crankshaft is provided with a crankshaft phase mark (14), and the air compressor cylinder is provided with an air compressor cylinder phase mark (15). When the crankshaft phase mark (14) is located between the two air compressor cylinder phase marks (15) along the circumference of the crankshaft, the air compressor is at a second preset angle after the top dead center of the air compressor.

10. The engine gear transmission system according to claim 9, characterized in that, The air compressor cylinder is provided with a bearing seat, and the bearing seat is provided with an upper limit mark (16) and a lower limit mark (17). Along the circumference of the bearing seat, the air compressor cylinder phase mark (15) is located between the upper limit mark (16) and the lower limit mark (17). The crankshaft phase mark (14) is located between the upper limit mark (16) and the lower limit mark (17) along the circumference of the crankshaft, and the air compressor is at a second preset angle after the top dead center of the air compressor.

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