Commercial vehicle automatic gearbox cross-step gear shifting method and system

Abstract

The invention provides a cross-step gear shifting method and system for an automatic gearbox of a commercial vehicle, which is applied to the technical field of automatic gear shifting of gearboxes and comprises the following steps of: calculating a target gear of cross-step gear shifting in real time; whether the cross-step gear shifting condition is met or not is judged in real time; if the cross-step gear shifting condition is not met, normal upshift / downshift operation is executed; and if the cross-order gear shifting condition is met, the cross-order upshift operation or the cross-order downshift operation is correspondingly executed. Whether the step-crossing gear shifting is triggered or not is judged through the vehicle parameters, in the step-crossing gear shifting target gear calculation process, the boundary value and the flag bit array of rotating speed protection are combined, rapid calculation and accurate control over the target gear are achieved, and the safety, stability and adaptability of step-crossing gear shifting are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of automatic gear shifting of gearboxes, and particularly relates to a method and system for skip shifting of a commercial vehicle automatic gearbox. Background Art

[0002] With the development of intelligent control technology, automatic gearboxes have been widely used in various commercial vehicles. Due to their advantages such as smooth gear shifting, easy driving, and fuel saving, automatic gearboxes have gradually replaced traditional manual gearboxes and become one of the mainstream configurations.

[0003] In the prior art, the gear shifting control logic of automatic gearboxes mostly controls based on a gear shifting map, which sets corresponding upshift points and downshift points according to different combinations of throttle openings and vehicle speeds. When the vehicle speed reaches the upshift point, it automatically upshifts, and when it drops to the downshift point, it automatically downshifts. Although this method is simple and easy to use, it also has the following technical limitations: The target gear calculation strategy is fixed and does not support skip shifting operations. The traditional gear shifting logic strictly follows upshifting and downshifting one gear at a time, lacking the ability to perform "jumping" gear shifts (such as directly shifting from the 3rd gear to the 5th gear or directly shifting from the 8th gear to the 6th gear) according to the actual road conditions and driving requirements, and unable to meet the needs of the vehicle for quickly adjusting the transmission system in different operating states.

[0004] The gear shifting calculation process is complex and the response time is long. Some existing solutions for skip shifting need to judge whether each gear meets the gear shifting conditions one by one, and the traversal query results in a response lag, unable to meet the fast response requirements under high-speed working conditions.

[0005] There is a lack of a safety boundary protection mechanism. When the system performs a skip shifting operation, if the rotational speed ranges of each gear are not fully restricted, it is easy to cause the engine rotational speed to be too low (risk of stalling) or too high (risk of overspeed) after gear shifting, reducing the system stability and service life.

[0006] Therefore, how to achieve a more flexible, fast and safe-protected skip shifting mechanism while ensuring the accuracy of the gear shifting logic has become an important research direction for the current automatic gearbox control strategy. Summary of the Invention

[0007] In view of the above problems in the prior art, the purpose of the present invention is to provide a method for skip shifting of a commercial vehicle automatic gearbox. By judging whether to trigger skip shifting through vehicle parameters, and combining the boundary values of rotational speed protection and the flag bit array during the calculation process of the skip shifting target gear, the fast calculation and precise control of the target gear are realized, improving the safety, stability and adaptability of skip shifting.

[0008] A method for skip shifting of a commercial vehicle automatic gearbox includes the following steps: Calculate the target gear for cross - step shifting in real time, which includes the following steps: S1. Collect and process vehicle information, where the vehicle information includes the gear number array D, the current throttle opening, and the current vehicle speed; S2. Calculate the up - shift flag bit array B1 and the down - shift flag bit array B2; S3. Obtain the maximum up - shift gear at the current throttle opening and vehicle speed according to the gear number array D and the up - shift flag bit array B1, or obtain the minimum down - shift gear at the current throttle opening and vehicle speed according to the gear number array D and the down - shift flag bit array B2; S4. Set the protection speeds for each gear, where the protection speeds include the minimum protection speed and the maximum protection speed; S5. Obtain the minimum speed array C1 according to the minimum protection speed and the maximum speed array C2 according to the maximum protection speed; S6. Calculate the boundary values for allowing up / down shifting at the current vehicle speed based on the minimum speed array C1 and the maximum speed array C2; S7. Obtain the predicted target gear for cross - step shifting: When cross - step up - shifting, select the maximum value between the maximum up - shift gear and the up - shift boundary value as the predicted up - shift target gear; when cross - step down - shifting, select the minimum value between the minimum down - shift gear and the down - shift boundary value as the predicted down - shift target gear; S8. Obtain the target gear for cross - step shifting: When cross - step up - shifting, select the minimum value between the predicted up - shift target gear and the corresponding up - shift gear in the shift diagram as the up - shift target gear; when cross - step down - shifting, select the maximum value between the predicted down - shift target gear and the corresponding down - shift gear in the shift diagram as the down - shift target gear.

[0009] Preferably, it further includes the following steps: Judge in real time whether the current conditions meet the requirements for cross - step shifting: If the conditions for cross - step shifting are not met, perform normal up / down shifting operations; If the conditions for cross - step shifting are met, perform corresponding cross - step up - shifting operations or cross - step down - shifting operations; The cross - step shifting includes cross - step up - shifting and cross - step down - shifting. The triggering conditions for cross - step up - shifting include: the current throttle opening is at least greater than 50%; the current gear acceleration is greater than the current gear calibration value; the current vehicle is not in a heavy - load condition; the current road condition does not belong to a large - slope road condition; The triggering conditions for cross - step down - shifting include: the brake flag is set to 1; the current gear acceleration is less than the current gear calibration value; the current vehicle is not in a heavy - load condition; the current road condition does not belong to a large - slope road condition.

[0010] Preferably, the process of calculating the up - shift flag bit array B1 and the down - shift flag bit array B2 specifically includes the following steps: According to the gear position array D and the current throttle opening, obtain the upshift / downshift points of each gear at the current throttle opening based on the shift map, and obtain the upshift / downshift array A, including the upshift array A1 and the downshift array A2; Calculate the input shaft speed array V of each gear at the current vehicle speed according to the current vehicle speed; Compare the upshift / downshift array A and the input shaft speed array V to obtain the upshift / downshift flag bit array B.

[0011] Preferably, in the calculation process of the target gear for upshifting, if the value of array A1 is not less than the value of array A2, the result is true and the flag bit is 0, otherwise the result is false and the flag bit is 1, to obtain the upshift flag bit array B1; In the calculation process of the target gear for downshifting, if the value of array A1 is not greater than the value of array A2, the result is true and the flag bit is 0, otherwise the result is false and the flag bit is 1, to obtain the downshift flag bit array B2.

[0012] Preferably, the calculation formula for the maximum upshift gear is: Min((( [B1] × weight) + (~[B1])) × [D]).

[0013] Preferably, the calculation formula for the minimum downshift gear is: Max((~[B2]) × [D]).

[0014] Preferably, the process of calculating the upshift boundary value allowed at the current vehicle speed based on the minimum speed array C1 and the maximum speed array C2 specifically includes the following steps: Calculate the upshift flag bit array B1' based on speed protection: If the value of the input shaft speed array A2 is not greater than the value of the minimum speed array C1, the result is true and the flag bit is 0, otherwise the result is false and the flag bit is 1, to obtain the upshift flag bit array B1'; Calculate the upshift boundary value allowed at the current vehicle speed based on the upshift flag bit array B1'. The calculation formula for the upshift boundary value is: Min((( [B1'] × weight) + (~[B1'])) × [D]).

[0015] Preferably, the process of calculating the downshift boundary value allowed at the current vehicle speed based on the minimum speed array C1 and the maximum speed array C2 specifically includes the following steps: Calculate the downshift flag bit array B2' based on speed protection: If the value of the input shaft speed array A2 is not less than the value of the maximum speed array C2, the result is true and the flag bit is 0, otherwise the result is false and the flag bit is 1, to obtain the downshift flag bit array B2'; Calculate the downshift boundary value allowed at the current vehicle speed based on the downshift flag bit array B2'. The calculation formula for the downshift boundary value is: Max((~[B2']) × [D]).

[0016] Preferably, after the cross-step upshift is completed, a corresponding delay protection time is set, and downshifting operations are prohibited within the delay protection time; after the cross-step downshift is completed, a corresponding delay protection time is set, and upshifting operations are prohibited within the delay protection time.

[0017] Another object of the present invention is to provide a cross-step shifting system for a commercial vehicle automatic transmission, which is used to execute the above-mentioned cross-step shifting method for a commercial vehicle automatic transmission. The cross-step shifting system for a commercial vehicle automatic transmission includes a target gear calculation module, which is used to calculate the target gear for cross-step shifting in real time; A judgment module, which is used to judge whether the vehicle currently meets the conditions for cross-step shifting; A control module, which is used to drive the vehicle to perform corresponding shifting operations based on the judgment result of the judgment module and the target gear calculated by the target gear calculation module.

[0018] The beneficial effects of the present invention are as follows: for the cross-step shifting method and system of the commercial vehicle automatic transmission, 1. The safety and reliability of the system are enhanced. By introducing the minimum protection speed array C1 and the maximum protection speed array C2 and setting the deviation compensation value, the safety boundary value for shifting is calculated and incorporated into the screening process of the target gear, ensuring that the engine operates within a reasonable speed range after shifting, effectively avoiding risks such as stalling or engine overspeed during shifting, thereby improving the safety of the system and the reliability of the whole vehicle.

[0019] 2. The system calculation load is reduced and the control efficiency is improved. Through the bit operation and weighted calculation of the flag bit array and the gear number array, replacing the traditional nested conditional judgment and traversal judgment, the shifting decision logic is greatly simplified, the calculation speed and processing efficiency of the shifting target are improved, and it is particularly suitable for deployment in the commercial vehicle controller environment with limited ECU resources.

[0020] 3. The shifting response speed and driving experience are improved. By adopting a multi-parameter judgment strategy based on the throttle opening, gear acceleration, vehicle load, and road condition information, combined with the dynamically generated up / down shift flag bit array and the maximum / minimum shift boundary gears, it is possible to directly perform shifting operations that skip multiple gears (i.e., cross-step shifting) on the premise of meeting the conditions, effectively avoiding the delay caused by judging each gear one by one, and improving the vehicle shifting response speed and power response ability. Description of the Drawings

[0021] The drawings are used to provide a further understanding of the present invention, and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention, and do not constitute a limitation to the present invention. In the drawings: Figure 1 is the flowchart of the method of the present invention; Figure 2is the flow chart for calculating the target gear of the present invention; Figure 3 is the flow chart for the execution process of skip-shifting of the present invention. Detailed implementation manners

[0022] Embodiment 1 As Figure 1 , Figure 3 shown, a skip-shifting method for a commercial vehicle automatic transmission includes the following steps: Calculate in real time the target gear for skip-shifting; Judge in real time whether the vehicle currently meets the conditions for skip-shifting: If the conditions for skip-shifting are not met, perform normal up / down shifting operations; If the conditions for skip-shifting are met, perform corresponding skip upshifting operations or skip downshifting operations; wherein, after skip upshifting is completed, set a corresponding delay protection time, and prohibit downshifting operations within the delay protection time; after skip downshifting is completed, set a corresponding delay protection time, and prohibit upshifting operations within the delay protection time.

[0023] As Figure 2 shown, the process of calculating the target gear for skip-shifting is as follows: (1) Obtain the gear number array D and the current throttle opening, and query the up / down shift points of all gears at the current throttle opening through the shift map to obtain the up / down shift array A, including the upshift array A1 and the downshift array A2.

[0024] (2) Obtain the current vehicle speed, and calculate the input shaft speed array V corresponding to all gears at the current vehicle speed; (3) By comparing the up / down shift array A and the input shaft speed array V, obtain the up / down shift flag bit array B, including the upshift flag bit array B1 and the downshift flag bit array B2.

[0025] Among them, in the process of calculating the target gear for upshifting, if the value of the array A1 is not less than the value of the array A2, the result is true and the flag bit is 0, otherwise the result is false and the flag bit is 1, to obtain the upshift flag bit array B1. In the process of calculating the target gear for downshifting, if the value of the array A1 is not greater than the value of the array A2, the result is true and the flag bit is 0, otherwise the result is false and the flag bit is 1, to obtain the downshift flag bit array B2.

[0026] (4) Based on the shift map, obtain the maximum upshift gear at the current throttle opening and vehicle speed according to the gear number array D and the upshift flag bit array B1; obtain the minimum downshift gear at the current throttle opening and vehicle speed according to the gear number array D and the downshift flag bit array B2.

[0027] The calculation formula for the maximum upshift gear is: Min((( [B1] × 127) + (~[B1])) × [D]).

[0028] The calculation formula for the minimum downshift gear is: Max((~[B2]) × [D]).

[0029] Where, [X] is an array expression, and ~ is the negation symbol.

[0030] (5) According to the hardware conditions of the engine and the transmission, set the protection speed for each gear. The protection speed includes the minimum protection speed and the maximum protection speed.

[0031] Where, a lower deviation compensation value is added to the minimum protection speed to obtain the minimum speed array C1; an upper deviation compensation value is added to the maximum protection speed to obtain the maximum speed array C2.

[0032] The protection speed needs to be set according to the hardware conditions of the engine and the transmission. During actual use, it needs to work within the normal operating range of the ability value. Therefore, an upper deviation compensation value or a lower deviation compensation value is added to this ability value to narrow the working range to protect the hardware device from being damaged due to long-term operation under overload, thereby achieving speed protection.

[0033] (6) Calculate the boundary values for allowing upshift / downshift at the current vehicle speed based on the minimum speed array C1 and the maximum speed array C2.

[0034] First, calculate the upshift flag bit array B1' based on speed protection: If the value of the input shaft speed array A2 is not greater than the value of the minimum speed array C1, the result is true and the flag bit is 0; otherwise, the result is false and the flag bit is 1, to obtain the upshift flag bit array B1'.

[0035] Calculate the allowable upshift boundary value at the current vehicle speed based on the upshift flag bit array B1'. The calculation formula is: Min((( [B1'] × 127) + (~[B1'])) × [D]).

[0036] Second, calculate the downshift flag bit array B2' based on speed protection: If the value of the input shaft speed array A2 is not less than the value of the maximum speed array C2, the result is true and the flag bit is 0; otherwise, the result is false and the flag bit is 1, to obtain the downshift flag bit array B2'.

[0037] Calculate the allowable downshift boundary value at the current vehicle speed based on the downshift flag bit array B2'. The calculation formula is: Max((~[B2']) × [D]).

[0038] (7) Obtain the predicted target gear for skip shifting: When skip upshifting, select the maximum value between the maximum upshift gear and the upshift boundary value as the predicted upshift target gear; when skip downshifting, select the minimum value between the minimum downshift gear and the downshift boundary value as the predicted downshift target gear.

[0039] (8) Obtain the target gear for skip shifting: When skip upshifting, select the minimum value between the predicted upshift target gear and the corresponding upshift gear in the shift map as the upshift target gear; when skip downshifting, select the maximum value between the predicted downshift target gear and the corresponding downshift gear in the shift map as the downshift target gear.

[0040] Hereinafter, the process of calculating the target gear will be described through a specific shift map. Assume the shift map is as shown in Table 1.

[0041]

[0042] Table 1 (1) Obtain that the current throttle opening is 80%, and the gear array D is [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12]. Then, according to the shift map, the upshift array A1 is [1600, 1700, 1750, 1600, 1550, 1750, 1600, 1600, 1550, 1650, 1700, 8000], and the downshift array A2 is [0, 750, 800, 900, 950, 900, 900, 850, 900, 900, 950, 1000].

[0043] (2) Assume that the input shaft speed array V calculated according to the current vehicle speed is [7000, 6000, 4500, 4000, 3000, 2500, 1500, 1000, 800, 600, 400, 200].

[0044] Among them, since the vehicle speed calculation formula is:

[0045] Therefore, the input shaft speed calculation formula is:

[0046] (3) Compare the up / downshift array A and the input shaft speed array V to obtain the up / downshift flag bit array.

[0047] Calculate the upshift flag bit array B1 at the current throttle opening and vehicle speed: [7000, 6000, 4500, 4000, 3000, 2500, 1500, 1000, 800, 600, 400, 200] > [1600, 1700, 1750, 1600, 1550, 1750, 1600, 1600, 1550, 1650, 1700, 8000] == [1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0].

[0048] Calculate the downshift flag bit array B2 at the current throttle opening and vehicle speed: [7000, 6000, 4500, 4000, 3000, 2500, 1500, 1000, 800, 600, 400, 200] < [0, 750, 800, 900, 950, 900, 900, 850, 900, 900, 950, 1000] == [0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1].

[0049] (4) Calculate the maximum upshift gear at the current throttle opening and vehicle speed: Min((([1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0] × 127) + (~[1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0])) × [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12]) == Min[127, 127, 127, 127, 127, 127, 7, 8, 9, 10, 11, 12] == 7.

[0050] Calculate the minimum downshift gear at the current throttle opening and vehicle speed: Max(~([0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1]) × [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12]) = Max[1, 2, 3, 4, 5, 6, 7, 8, 0, 0, 0, 0] == 8.

[0051] (5) Assume the minimum protection speed of the engine in each gear is: [500, 500, 500, 600, 600, 600, 650, 650, 650, 700, 700, 700]; Assume the lower deviation value for calibrating the minimum protection speed of the engine in each gear is: [250, 250, 250, 200, 200, 200, 100, 100, 100, 50, 50, 50]; Therefore, the minimum speed array C1 is [750, 750, 750, 800, 800, 800, 750, 750, 750, 750, 750, 750].

[0052] Assume the maximum protection speed of the engine in each gear is: [3000, 3000, 3000, 2800, 2800, 2800, 2500, 2500, 2500, 2300, 2300, 2300]; Assume the upper deviation value of the maximum protection speed of the engine calibrated for each gear is: [-300, -300, -300, -200, -200, -200, -150, -150, -150, -100, -100, -100]; Therefore, the maximum speed array C2 is obtained as [2700, 2700, 2700, 2600, 2600, 2600, 2450, 2450, 2450, 2200, 2200].

[0053] (6) Calculate the upshift flag bit array B1' based on speed protection: [7000, 6000, 4500, 4000, 3000, 2500, 1500, 1000, 800, 600, 400, 200] > [750, 750, 750, 800, 800, 800, 750, 750, 750, 750, 750, 750] == [1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0].

[0054] Calculate the allowable upshift boundary value at the current vehicle speed based on the upshift flag bit array B1': Min((([1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0] × 127) + (~[1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0])) × [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12]) == Min[127, 127, 127, 127, 127, 127, 127, 127, 127, 127, 11, 12] == 11.

[0055] Calculate the downshift flag bit array B2' based on speed protection: [7000, 6000, 4500, 4000, 3000, 2500, 1500, 1000, 800, 600, 400, 200] < [2700, 2700, 2700, 2600, 2600, 2600, 2450, 2450, 2450, 2200, 2200] == [0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1].

[0056] Calculate the allowable downshift boundary value at the current vehicle speed based on the downshift flag bit array B2': Max(~([0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1]) × [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12]) = Max[1, 2, 3, 4, 5, 0, 0, 0, 0, 0, 0, 0] == 5.

[0057] (7)Obtain the predicted target gear for skip shifting: Predicted upshift target gear: MAX (maximum upshift gear, upshift boundary value) == MAX (7, 11) == 11.

[0058] Predicted downshift target gear: Min (minimum downshift gear, downshift boundary value) == Min (8, 5) == 5.

[0059] (8)Obtain the target gear for skip shifting: Upshift target gear: Min (predicted upshift target gear, minimum value in the upshift gear corresponding to the shift map) == Min (11, 11) == 11.

[0060] Downshift target gear: Max (predicted downshift target gear, maximum value in the downshift gear corresponding to the shift map) == Max (5, 5) == 5.

[0061] The triggering conditions for skip upshifting include: the current throttle opening is at least greater than 50%; the current gear acceleration is greater than the current gear calibration value; the current vehicle is not in a heavy load condition; the current road condition does not belong to a large slope road condition. It should be noted that all conditions for skip upshifting must be met to trigger the skip upshifting operation.

[0062] After triggering skip upshifting, perform an upshifting operation according to the calculated target gear. When the current gear is the same as the target gear, the current skip upshifting ends. It should be noted that in order to ensure that there will be no immediate downshift due to conflict with the normal downshifting operation based on the shift map after upshifting is completed, a delay protection time is set after skip upshifting, and downshifting based on the shift map is prohibited during this time.

[0063] The exit conditions for skip upshifting include: the throttle opening is less than the calibration value; the current vehicle is in a heavy load condition; the current road condition belongs to a large slope road condition; the brake flag is at position 1.

[0064] The triggering conditions for skip downshifting include: the brake flag is at position 1; the current gear acceleration is less than the current gear calibration value; the current vehicle is not in a heavy load condition; the current road condition does not belong to a large slope road condition.

[0065] Similarly, after triggering the skip-downshift, a downshift operation is performed according to the calculated target gear. When the current gear is the same as the target gear, the current skip-downshift ends. It should be noted that in order to ensure that an upshift is not immediately triggered due to a conflict with the normal upshift operation based on the shift map after the downshift is completed, a delay protection time is set after the skip-downshift ends, and the upshift operation based on the shift map is prohibited during this time.

[0066] The skip-downshift exit conditions include: the brake flag position is 0; the current vehicle is in a heavy-load condition; the current road condition is a large-gradient road condition; the current gear acceleration is greater than the current gear calibration value.

[0067] Embodiment 2 The second aspect of the present invention proposes a skip-shifting system for a commercial vehicle automatic transmission, which is used to execute the skip-shifting method for a commercial vehicle automatic transmission described in Embodiment 1.

[0068] The skip-shifting system for the commercial vehicle automatic transmission includes a target gear calculation module, a judgment module, and a control module. Among them, the target gear calculation module is used to calculate the target gear for skip-shifting in real time; the judgment module is used to judge whether the vehicle currently meets the conditions for skip-shifting; the control module is used to drive the vehicle to perform corresponding shifting operations based on the target gear calculated by the target gear calculation module according to the judgment result of the judgment module.

[0069] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for cross-gear shifting of a commercial vehicle automatic transmission, characterized in that, It includes the following steps: Calculate the target gear for skip shifting in real time, which includes the following steps: S1. Collect and process vehicle information, where the vehicle information includes the gear array D, the current throttle opening, and the current vehicle speed; S2. Calculate the upshift flag bit array B1 and the downshift flag bit array B2; S3. Obtain the maximum upshift gear at the current throttle opening and vehicle speed according to the gear array D and the upshift flag bit array B1, or obtain the minimum downshift gear at the current throttle opening and vehicle speed according to the gear array D and the downshift flag bit array B2; S4. Set the protection speed for each gear, where the protection speed includes the minimum protection speed and the maximum protection speed; S5. Obtain the minimum speed array C1 according to the minimum protection speed and the maximum speed array C2 according to the maximum protection speed; S6. Calculate the boundary values for up / down shifting allowed at the current vehicle speed based on the minimum speed array C1 and the maximum speed array C2; S7. Obtain the predicted target gear for skip shifting: When skip upshifting, select the maximum value between the maximum upshift gear and the upshift boundary value as the predicted upshift target gear; when skip downshifting, select the minimum value between the minimum downshift gear and the downshift boundary value as the predicted downshift target gear; S8. Obtain the target gear for skip shifting: When skip upshifting, select the minimum value between the predicted upshift target gear and the corresponding upshift gear in the shift diagram as the upshift target gear; when skip downshifting, select the maximum value between the predicted downshift target gear and the corresponding downshift gear in the shift diagram as the downshift target gear.

2. The method for stepped shifting of a commercial vehicle automatic transmission according to claim 1, wherein It also includes the following steps: Judge in real time whether the current condition meets the requirements for skip shifting: If the condition for skip shifting is not met, perform normal up / down shifting operations; If the condition for skip shifting is met, perform the corresponding skip upshift operation or skip downshift operation; The skip shifting includes skip upshifting and skip downshifting. The triggering conditions for skip upshifting include: the current throttle opening is at least greater than 50%; the current gear acceleration is greater than the current gear calibration value; the current vehicle is not in a heavy load condition; the current road condition does not belong to a large slope road condition; The triggering conditions for skip downshifting include: the brake flag is at position 1; the current gear acceleration is less than the current gear calibration value; the current vehicle is not in a heavy load condition; the current road condition does not belong to a large slope road condition.

3. The method for cross-gear shifting of a commercial vehicle automatic transmission according to claim 1, wherein The process of calculating the upshift flag bit array B1 and the downshift flag bit array B2 specifically includes the following steps: Based on the gear array D and the current throttle opening, obtain the up / down shift points for each gear at the current throttle opening according to the shift diagram, and obtain the up / down shift array A, including the upshift array A1 and the downshift array A2; Calculate the input shaft speed array V for each gear at the current vehicle speed according to the current vehicle speed; Compare the up / down shift array A and the input shaft speed array V to obtain the up / down shift flag bit array B.

4. The method for skip shifting of a commercial vehicle automatic transmission according to claim 3, characterized in that, During the calculation of the upshift target gear, if the value of array A1 is not less than the value of array A2, the result is true and the flag bit is 0, otherwise the result is false and the flag bit is 1, to obtain the upshift flag bit array B1; During the calculation of the downshift target gear, if the value of array A1 is not greater than the value of array A2, the result is true and the flag bit is 0, otherwise the result is false and the flag bit is 1, to obtain the downshift flag bit array B2.

5. The method for stepped shifting of a commercial vehicle automatic transmission according to claim 1, characterized in that, The calculation formula for the maximum upshift gear is: Min((( [B1] × weight) + (~[B1])) × [D]).

6. The method for cross-gear shifting of a commercial vehicle automatic transmission according to claim 1, characterized in that, The calculation formula for the minimum downshift gear is: Max((~[B2]) × [D]).

7. The method for skip shifting of a commercial vehicle automatic transmission according to claim 1, characterized in that, The process of calculating the boundary value for allowing upshifts at the current vehicle speed based on the minimum speed array C1 and the maximum speed array C2 specifically includes the following steps: Calculate the upshift flag bit array B1' based on speed protection: If the value of the input shaft speed array A2 is not greater than the value of the minimum speed array C1, the result is true and the flag bit is 0; otherwise, the result is false and the flag bit is 1, obtaining the upshift flag bit array B1'. Calculate the boundary value for allowing upshifts at the current vehicle speed based on the upshift flag bit array B1'. The calculation formula for the upshift boundary value is: Min((( [B1'] × weight) + (~[B1'])) × [D]).

8. The method for stepped shifting of a commercial vehicle automatic transmission according to claim 1, characterized in that, The process of calculating the boundary value for allowing downshifts at the current vehicle speed based on the minimum speed array C1 and the maximum speed array C2 specifically includes the following steps: Calculate the downshift flag bit array B2' based on speed protection: If the value of the input shaft speed array A2 is not less than the value of the maximum speed array C2, the result is true and the flag bit is 0; otherwise, the result is false and the flag bit is 1, obtaining the downshift flag bit array B2'. Calculate the boundary value for allowing downshifts at the current vehicle speed based on the downshift flag bit array B2'. The calculation formula for the downshift boundary value is: Max((~[B2']) × [D]).

9. The method for skip shifting of a commercial vehicle automatic transmission according to claim 1, characterized in that, After completing a stepped upshift, set the corresponding delay protection time, and prohibit downshift operations during the delay protection time; after completing a stepped downshift, set the corresponding delay protection time, and prohibit upshift operations during the delay protection time.

10. An automatic transmission cross-gear shifting system for a commercial vehicle, characterized in that, A commercial vehicle automatic transmission stepped shifting system for executing the commercial vehicle automatic transmission stepped shifting method as described in claims 1 to 9, the system includes a target gear calculation module for calculating the target gear of stepped shifting in real time; A judgment module for judging whether the vehicle currently meets the conditions for stepped shifting; A control module for driving the vehicle to perform corresponding shifting operations based on the judgment result of the judgment module and the target gear calculated by the target gear calculation module.

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