Method and system for selecting engine brake structure

Abstract

The present invention provides a method and system for selecting an engine brake structure. The selection method includes: obtaining big data statistical information of a target vehicle; determining the upper speed limit of the target vehicle when descending at various downhill slopes based on the big data statistical information; calculating the target braking power required for the target vehicle to achieve a balance at various speeds when driving at all slopes and all speeds; determining the engine speed and driving gear corresponding to the target braking power based on the power transmission parameters of the target vehicle; selecting the final speed and final braking power required for engine braking based on the target braking power, engine speed, driving gear, and upper speed limit; and determining the engine brake structure based on the final speed and final braking power. The method combines statistical data on actual user driving conditions to determine engine braking performance based on actual driving condition requirements, and selects the engine brake structure based on the engine braking performance, thereby ensuring that the engine brake structure better meets actual driving conditions.

Description

Technical Field

[0001] The present invention relates to the technical field of engine braking, and in particular to a method and system for selecting an engine braking structure. Background Art

[0002] As a supplement to the basic wheel brakes of heavy-duty vehicles, auxiliary braking greatly improves the safety of driving on slopes and effectively reduces the wear of wheel brakes. Among them, auxiliary braking includes: retarder braking, engine braking and motor braking.

[0003] Different engine braking structures achieve different braking powers. In the early stages of engine development, it is necessary to select the engine braking structure based on the actual needs of the user in order to achieve the desired braking effect.

[0004] At present, in the early stage of engine development, the engine's braking structure has not fully taken into account the actual needs of users, which leads to unsatisfactory engine braking effect. Summary of the Invention

[0005] The main purpose of the present invention is to provide a method and system for selecting an engine brake structure, so as to solve the technical problem that the selection of the engine brake structure does not fully take into account the actual needs of users.

[0006] To achieve the above-mentioned purpose, according to one aspect of the present invention, a method for selecting an engine braking structure is provided, comprising: obtaining big data statistical information of a target vehicle, wherein the big data statistical information includes at least: driving speed, downhill gradient and mileage; determining an upper limit speed of the target vehicle when descending at each downhill gradient based on the big data statistical information; calculating a target braking power required for the target vehicle to achieve a balance at each speed when traveling at all gradients and all speeds; determining an engine speed and driving gear corresponding to the target braking power based on power transmission parameters of the target vehicle, wherein the power transmission parameters include: transmission ratio, wheel radius and main reducer ratio; selecting a final speed and final braking power required for engine braking based on the target braking power, engine speed, driving gear and upper limit speed; and determining the engine braking structure based on the final speed and final braking power.

[0007] Furthermore, based on the big data statistical information, the upper limit speed of the target vehicle when going downhill at each downhill slope is determined, including: constructing a data statistical table of slope-speed-mileage distribution based on the big data statistical information, the data statistical table is used to characterize the proportion of mileage of the target vehicle traveling at any speed on each downhill slope; based on the data statistical table and the preset proportion, the upper limit speed is determined.

[0008] Furthermore, based on the data statistics table and the preset proportion, the upper limit speed is determined, including: at the first downhill slope, summing the first driving speed and the mileage proportion corresponding to a speed lower than the first driving speed to obtain a first mileage proportion; at the first downhill slope, summing the mileage proportion corresponding to each driving speed to obtain a first total mileage proportion at the slope; taking the first mileage proportion and the first total mileage proportion as the quotient to obtain a first proportion; when the first proportion is equal to the preset proportion, confirming the first driving speed as the upper limit speed.

[0009] Furthermore, the target braking power required for the target vehicle to achieve balance at various speeds when traveling at all slopes and all speeds is calculated, including: obtaining the total mass, driving resistance power, driving speed, full slope range, and full speed range of the target vehicle; and calculating the target braking power based on the total mass, driving resistance power, driving speed, full slope range, and full speed range.

[0010] Furthermore, before determining the engine speed and driving gear corresponding to the target braking power, it is necessary to construct a first comparison table of vehicle speed-slope-target braking power. The first comparison table is used to represent the first braking power required for the target vehicle to travel at any average speed on each downhill slope, wherein the first braking power is the target braking power.

[0011] Furthermore, based on the power transmission parameters of the target vehicle, the engine speed and driving gear corresponding to the target braking power are determined, including: calculating the driving speed corresponding to each engine speed in each transmission gear according to the power transmission parameters of the target vehicle, and constructing a second speed-gear-vehicle speed comparison table; based on the second comparison table and the first comparison table, multiple third comparison tables are obtained, and the multiple third comparison tables are used to represent the second braking power required for the engine to run at any speed and any gear at each downhill slope, wherein the second braking power is the target braking power.

[0012] Furthermore, based on the target braking power, engine speed, driving gear and upper limit vehicle speed, the final speed and final braking power required for engine braking are selected, including: combining the second comparison table and the first comparison table, selecting multiple driving gears that match the upper limit vehicle speed from the third comparison table; determining the final gear from the selected multiple driving gears in combination with the downhill slope corresponding to the upper limit vehicle speed; determining the target speed corresponding to the target braking power based on the final gear; drawing speed-braking power scatter points based on the target speed and target braking power, selecting the outermost scatter points for envelope connection, and generating a speed-braking power curve; and determining the final speed and final braking power based on the speed-braking power curve.

[0013] Furthermore, in combination with the downhill slope corresponding to the upper limit vehicle speed, the final gear is determined from the selected multiple driving gears, including: when the downhill slope corresponding to the upper limit vehicle speed is greater than or equal to the preset slope, the lower gear among the multiple driving gears is selected as the final gear.

[0014] Furthermore, in combination with the downhill slope corresponding to the upper limit vehicle speed, the final gear is determined from the selected multiple driving gears, including: when the downhill slope corresponding to the upper limit vehicle speed is less than the preset slope, the higher gear among the multiple driving gears is selected as the final gear.

[0015] According to another aspect of the present invention, a system for selecting an engine brake structure is provided, comprising: an acquisition module, the acquisition module being used to acquire big data statistical information of a target vehicle, wherein the big data statistical information includes at least: driving speed, downhill gradient, and mileage; a first calculation module, the first calculation module being used to determine, based on the big data statistical information, an upper limit speed of the target vehicle when descending at each downhill gradient; a second calculation module, the second calculation module being used to calculate a target braking power required for the target vehicle to achieve a balance at each speed when traveling at all gradients and all speeds; a third calculation module, the third calculation module being used to determine, based on power transmission parameters of the target vehicle, an engine speed and a driving gear corresponding to the target braking power, wherein the power transmission parameters include: a transmission ratio, a wheel radius, and a transmission ratio of a final reducer; a first selection module, the first selection module being used to select a final speed and a final braking power required for engine braking based on the target braking power, the engine speed, the driving gear, and the upper limit speed; and a second selection module, the second selection module being used to determine the engine braking structure based on the final speed and the final braking power.

[0016] The technical solution of the present invention determines the upper speed limit for downhill descents at various downhill slopes based on statistical data from the target vehicle. The final speed and braking power required for engine braking are determined based on the upper speed limit, the target braking power required for the target vehicle downhill, and the target vehicle's powertrain parameters. The engine braking structure is then determined based on these final speeds and braking power. This solution combines statistical data from actual user driving conditions to determine engine braking performance based on actual driving conditions. The corresponding engine braking structure is then selected based on this performance, ensuring that the specified engine braking structure is more consistent with actual driving conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0018] Figure 1A schematic flow chart showing a method for selecting an engine brake structure in the present invention is shown;

[0019] Figure 2 A schematic diagram of a curve of engine speed-braking power in the present invention is shown. DETAILED DESCRIPTION

[0020] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0021] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0022] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way are interchangeable where appropriate, so that the embodiments of the present application described herein can, for example, be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0023] Now, exemplary embodiments according to the present application will be described in more detail with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in a variety of different forms and should not be interpreted as being limited to the embodiments described herein. It should be understood that these embodiments are provided to make the disclosure of this application thorough and complete, and to fully convey the concepts of these exemplary embodiments to those of ordinary skill in the art. In the accompanying drawings, for the sake of clarity, the thickness of layers and regions may be exaggerated, and the same reference numerals are used to represent the same devices, and thus their descriptions will be omitted.

[0024] Combine Figure 1 As shown, according to a specific embodiment of the present application, a method for selecting an engine brake structure is provided.

[0025] Specifically, the method for selecting the engine brake structure includes the following steps:

[0026] Step S1: Obtain big data statistical information of the target vehicle, wherein the big data statistical information at least includes: driving speed, downhill slope and mileage.

[0027] Step S2: Determine the upper speed limit of the target vehicle when going downhill at each downhill slope based on the big data statistical information.

[0028] Step S3: Calculate the target braking power required for the target vehicle to achieve a balance at each speed when the target vehicle is traveling at all slopes and all speeds.

[0029] Step S4: determining the engine speed and driving gear corresponding to the target braking power according to the power transmission parameters of the target vehicle, wherein the power transmission parameters include: transmission ratio, wheel radius, and final drive ratio.

[0030] Step S5: According to the target braking power, engine speed, driving gear and upper speed limit, the final speed and final braking power required for engine braking are selected.

[0031] Step S6: Determine the engine braking structure based on the final rotational speed and the final braking power.

[0032] In an embodiment of the present application, based on the target vehicle's big data statistics, an upper speed limit for downhill descents at various gradients is determined. The final speed and braking power required for engine braking are determined based on the upper speed limit, the target braking power required for the target vehicle downhill, and the target vehicle's powertrain parameters. The engine braking structure is then determined based on the final speed and braking power. This approach, combined with actual user driving condition statistics, determines engine braking performance based on actual operating conditions. The corresponding engine braking structure is selected based on this engine braking performance, thereby ensuring that the established engine braking structure better matches actual driving conditions.

[0033] It should be noted that the preset vehicle matched with the engine to be developed has the same vehicle operating conditions as the target vehicle, wherein the vehicle operating conditions include at least: the total mass of the vehicle and the driving area of ​​the vehicle.

[0034] In an exemplary embodiment of the present application, determining the upper speed limit of the target vehicle when descending at each downhill slope based on the big data statistical information in step S2 includes the following steps:

[0035] Step S21: constructing a data statistical table of slope-speed-mileage distribution based on the big data statistical information. The data statistical table is used to characterize the mileage ratio of the target vehicle at each downhill slope at any speed.

[0036] Step S22: Determine the upper speed limit based on the data statistics table and the preset ratio, wherein the preset ratio can be calibrated according to actual needs.

[0037] Through the above steps S21 to S22, the big data statistical information is integrated into a data statistical table, and the mileage is divided according to the road slope and the vehicle speed. The mileage ratio of the target vehicle traveling at each speed in each downhill slope section can be quickly obtained, and then the upper limit speed can be determined in combination with the preset ratio.

[0038] For example, the data statistics table of the slope-speed-mileage distribution in step S21 is shown in the following table:

[0039] Data statistics table

[0040]

[0041] The specific calculation process for determining the upper speed limit based on the data statistics table and the preset ratio in step S22 is as follows:

[0042] Step S221: At a first downhill slope, sum the first driving speed and the mileage ratio corresponding to a speed lower than the first driving speed to obtain a first mileage ratio.

[0043] Illustratively, the first downhill gradient is -6 to -7%, the first driving speed is 75 to 80 km / h, and the first mileage proportion C1 is calculated according to the above data statistical table: C1=0.02+0.02+...+0.01+0.01+0.01.

[0044] Step S222: At a first downhill slope, sum the mileage percentages corresponding to the various vehicle speeds to obtain a first total mileage percentage at the slope.

[0045] Illustratively, the first downhill slope is -6 to -7%. The first total mileage proportion C2 is calculated according to the above data statistical table, C2=0.01+0.01+0.01+0.02+0.02+…+0.01+0.01+0.01.

[0046] Step S223: Calculate the quotient of the first mileage proportion and the first total mileage proportion to obtain the first proportion.

[0047] Exemplarily, the first proportion C0 = C1 / C2.

[0048] Step S224: When the first proportion is equal to the preset proportion, the first driving speed is confirmed as the upper limit speed.

[0049] For example, the preset proportion is 90%. If C0=90%, 75-80 km / h is determined as the upper limit speed for driving under -6--7%. If C0≠90%, C1 is adjusted according to the above data statistics table.

[0050] In an exemplary embodiment of the present application, the calculation of the target braking power required for the target vehicle to achieve a balance at various vehicle speeds when the target vehicle is traveling at all slopes and all speeds in step S3 includes the following calculation steps:

[0051] Step S31: Obtain the total mass, driving resistance power, driving speed, full slope range and full speed range of the target vehicle.

[0052] Step S32: Calculate the target braking power according to the total mass, driving resistance power, driving speed, full slope range and full speed range.

[0053] Specifically, the target braking power is P0, the total mass of the target vehicle is M, and the driving resistance power of the target vehicle is P 1， The road slope angle is θ, the acceleration of gravity is g, and the speed of the target vehicle is u a , where P0 = Mg sinθ × u a -P1.

[0054] In an exemplary embodiment of the present application, before determining the engine speed and driving gear corresponding to the target braking power, it is necessary to construct a first comparison table of vehicle speed-slope-target braking power. The first comparison table is used to characterize the first braking power required for the target vehicle to travel at an average speed at any driving speed on each downhill slope, wherein the first braking power is the target braking power.

[0055] Specifically, the first lookup table is based on P0=Mg sinθ×u a -P1 is constructed, where the first comparison table is as follows:

[0056] First comparison table

[0057]

[0058] Furthermore, in step S4, the engine speed and driving gear corresponding to the target braking power are determined based on the power transmission parameters of the target vehicle, including the following calculation steps:

[0059] Step S41: Calculate the vehicle speed corresponding to each engine speed at each transmission gear according to the power transmission parameters of the target vehicle, and construct a second speed-gear-vehicle speed comparison table.

[0060] For example, the power transmission parameters of the target vehicle include: engine speed n, transmission ratio i g, the final reducer ratio i0 and the wheel radius r, the engine speed in each transmission gear corresponds to the driving speed u a , according to Construct a second lookup table, where the second lookup table is as follows:

[0061] Second comparison table

[0062]

[0063]

[0064] Step S42: Based on the second lookup table and the first lookup table, a plurality of third lookup tables are obtained, wherein the plurality of third lookup tables are used to characterize the second braking power required for the engine to run at any speed and any gear at each downhill slope, wherein the second braking power is the target braking power.

[0065] For example, the second comparison table is integrated with the first comparison table to obtain multiple third comparison tables. Taking the slope of -6% as an example, a third comparison table of speed-gear-power is constructed, wherein the third comparison table (slope of -6%) is as follows:

[0066] The third comparison table (slope is -6%)

[0067]

[0068] In an exemplary embodiment of the present application, in step S5, the final speed and final braking power required for engine braking are selected according to the target braking power, the engine speed, the driving gear, and the upper speed limit, including:

[0069] Step S51: combining the second lookup table and the first lookup table, and selecting a plurality of driving gears that match the upper speed limit from the third lookup table.

[0070] For example, taking a road slope of -6% as an example, when the road slope is -6%, the upper limit speed is 75km / h; according to the second comparison table, the speed corresponding to 75km / h is 2100rpm, and the corresponding driving gear is 8th gear; according to the third comparison table, when the engine runs at 8th gear 2100rpm, the target speed of the engine is 158.4kw.

[0071] Step S52: Determine the final gear position from the selected multiple driving gear positions in combination with the downhill slope corresponding to the upper speed limit.

[0072] For example, when driving on a road slope of -6%, the vehicle speed range is 0 to 75 km / h. According to the second comparison table and the third comparison table, the driving gears involved are 7th and 8th gears, that is, the final gears are 7th and 8th gears.

[0073] Step S53: Determine the target speed corresponding to the target braking power according to the final gear position.

[0074] Step S54: based on the target speed and the target braking power, the speed-braking power scatter points are plotted, and the outermost scatter points are selected for enveloping connection to generate a speed-braking power curve.

[0075] For example, according to the third comparison table, the scattered points are all the braking power points involved in the 7th and 8th gears; Figure 2 As shown in the figure, plot the speed-brake power scatter points, select the outermost scattered points and connect them to generate an envelope. The power point on the envelope is used as the engine's brake power.

[0076] Step S55: Determine the final speed and final braking power based on the speed-braking power curve. Figure 2 The power point on the envelope line is used as the braking power point of the engine, which corresponds to the final speed and final braking power.

[0077] Preferably, the final gear is determined from the selected multiple driving gears in combination with the downhill slope corresponding to the upper limit vehicle speed, including: when the downhill slope corresponding to the upper limit vehicle speed is greater than or equal to the preset slope, a lower gear among the selected multiple driving gears is selected as the final gear.

[0078] Preferably, the final gear is determined from the selected multiple driving gears in combination with the downhill slope corresponding to the upper limit vehicle speed, including: when the downhill slope corresponding to the upper limit vehicle speed is less than the preset slope, the higher gear among the selected multiple driving gears is selected as the final gear.

[0079] According to another specific embodiment of the present application, a system for selecting an engine brake structure is provided.

[0080] Specifically, the engine brake configuration selection system includes an acquisition module, a first calculation module, a second calculation module, a third calculation module, a first selection module, and a second selection module. The acquisition module is configured to acquire big data statistical information about the target vehicle, where the big data statistical information includes at least driving speed, downhill gradient, and mileage. The first calculation module is configured to determine the upper speed limit for the target vehicle at various downhill gradients based on the big data statistical information. The second calculation module is configured to calculate the target braking power required for the target vehicle to achieve a balanced speed at all speeds while driving at all gradients. The third calculation module is configured to determine the engine speed and driving gear corresponding to the target braking power based on the target vehicle's powertrain parameters, where the powertrain parameters include transmission ratio, wheel radius, and final drive ratio. The first selection module is configured to select the final speed and final braking power required for engine braking based on the target braking power, engine speed, driving gear, and upper speed limit. The second selection module is configured to determine the engine brake configuration based on the final speed and final braking power.

[0081] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0082] Based on the target vehicle's statistical data, the maximum speed limit for downhill driving at various gradients is determined. Combined with the maximum speed limit, the target braking power required for the target vehicle downhill, and the target vehicle's powertrain parameters, the final engine braking speed and braking power required are determined. The engine braking structure is then determined based on these final speeds and braking power. This approach, combined with actual user driving condition data, determines engine braking performance based on actual driving conditions. The corresponding engine braking structure is then selected based on this performance, ensuring that the established engine braking structure is more accurately aligned with actual driving conditions.

[0083] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used herein to describe the spatial positional relationship of a device or feature to other devices or features as shown in the figures. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figures. For example, if the device in the drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0084] In addition to the above, it should be noted that references to "one embodiment," "another embodiment," "an embodiment," and the like in this specification refer to specific features, structures, or characteristics described in conjunction with that embodiment as included in at least one embodiment generally described in this application. The appearance of the same expression in multiple places in the specification does not necessarily refer to the same embodiment. Furthermore, when a specific feature, structure, or characteristic is described in conjunction with any embodiment, it is intended that such feature, structure, or characteristic, when implemented in conjunction with other embodiments, also falls within the scope of the present invention.

[0085] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0086] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for selecting an engine brake structure, characterized in that: include: Obtaining big data statistical information of the target vehicle, wherein the big data statistical information includes at least: driving speed, downhill slope, and mileage; Determining an upper speed limit for the target vehicle when descending at each of the downhill slopes based on the big data statistical information; Calculating the target braking power required for the target vehicle to achieve a balanced speed at all speeds while traveling at all slopes; determining an engine speed and a driving gear corresponding to the target braking power according to power transmission parameters of the target vehicle, wherein the power transmission parameters include: a transmission ratio, a wheel radius, and a transmission ratio of a final drive; selecting a final speed and a final braking power required for engine braking according to the target braking power, the engine speed, the driving gear, and the upper speed limit; A braking structure of the engine is determined based on the final rotational speed and the final braking power.

2. The selection method according to claim 1, characterized in that: Determining the upper speed limit of the target vehicle when descending at each downhill slope based on the big data statistical information includes: Constructing a data statistical table of slope-speed-mileage distribution based on the big data statistical information, wherein the data statistical table is used to characterize the mileage ratio of the target vehicle at each downhill slope at any speed; The upper speed limit is determined based on the data statistics table and the preset ratio.

3. The selection method according to claim 2, characterized in that: Determining the upper speed limit based on the data statistics table and the preset proportion includes: At a first downhill slope, summing the first driving speed and the mileage ratio corresponding to a speed lower than the first driving speed to obtain a first mileage ratio; At the first downhill slope, the mileage percentages corresponding to the various vehicle speeds are summed to obtain the first total mileage percentage at the slope; Taking the first mileage proportion and the first total mileage proportion as a quotient to obtain a first proportion; When the first proportion is equal to the preset proportion, the first driving speed is confirmed as the upper limit speed.

4. The selection method according to claim 1, characterized in that: Calculating the target braking power required for the target vehicle to achieve a balanced speed at all speeds while traveling at all slopes, including: Obtaining the total mass, driving resistance power, driving speed, full slope range, and full speed range of the target vehicle; The target braking power is calculated according to the total mass, the driving resistance power, the driving speed, the full slope range, and the full vehicle speed range.

5. The selection method according to claim 4, characterized in that: Before determining the engine speed and driving gear corresponding to the target braking power, it is necessary to construct a first comparison table of vehicle speed-slope-target braking power. The first comparison table is used to represent the first braking power required for the target vehicle to travel at an average speed at any driving speed on each downhill slope, wherein the first braking power is the target braking power.

6. The selection method according to claim 5, characterized in that: Determining an engine speed and a driving gear corresponding to the target braking power according to a power transmission parameter of the target vehicle includes: Calculating the vehicle speed corresponding to each engine speed at each transmission gear position based on the power transmission parameters of the target vehicle, and constructing a second speed-gear-vehicle speed comparison table; Based on the second comparison table and the first comparison table, multiple third comparison tables are obtained, and the multiple third comparison tables are used to characterize the second braking power required for the engine to run at any speed and any gear at each downhill slope, wherein the second braking power is the target braking power.

7. The selection method according to claim 6, characterized in that: Selecting a final speed and a final braking power required for engine braking according to the target braking power, the engine speed, the driving gear, and the upper speed limit includes: In combination with the second lookup table and the first lookup table, selecting a plurality of driving gears that match the upper speed limit from the third lookup table; Determining a final gear position from the selected multiple driving gear positions based on the downhill gradient corresponding to the upper speed limit; determining a target speed corresponding to the target braking power according to the final gear position; According to the target speed and the target braking power, a speed-braking power curve is generated by plotting scattered points, selecting the outermost scattered points for enveloping and connecting them, and forming a speed-braking power curve; The final speed and the final braking power are determined based on the speed-braking power curve.

8. The selection method according to claim 7, characterized in that: Determining the final gear position from the selected multiple driving gear positions in combination with the downhill slope corresponding to the upper speed limit includes: When the downhill slope corresponding to the upper limit vehicle speed is greater than or equal to the preset slope, a lower gear among the multiple driving gears is selected as the final gear.

9. The selection method according to claim 7, characterized in that: Determining the final gear position from the selected multiple driving gear positions in combination with the downhill slope corresponding to the upper speed limit includes: When the downhill slope corresponding to the upper speed limit is less than the preset slope, a higher gear among the multiple driving gears is selected as the final gear.

10. A system for selecting an engine brake structure, characterized in that: include: An acquisition module, the acquisition module is used to acquire big data statistical information of the target vehicle, wherein the big data statistical information at least includes: driving speed, downhill slope and mileage; a first calculation module, configured to determine an upper speed limit of the target vehicle when descending at each downhill slope based on the big data statistical information; a second calculation module, the second calculation module being used to calculate the target braking power required for the target vehicle to achieve a balance at each vehicle speed when the target vehicle is traveling at all slopes and all speeds; a third calculation module, configured to determine an engine speed and a driving gear corresponding to the target braking power based on power transmission parameters of the target vehicle, wherein the power transmission parameters include a transmission ratio, a wheel radius, and a final drive ratio; a first selection module, configured to select a final speed and a final braking power required for engine braking according to the target braking power, the engine speed, the driving gear, and the upper speed limit; The second selection module is used to determine the braking structure of the engine based on the final speed and the final braking power.

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