Shift control method for a dual clutch transmission

Abstract

The application provides a shift control method for a double clutch transmission, comprising the following steps: S1: detecting whether the automobile satisfies a 1st gear shift enabling condition; if yes, entering step S2. S2: detecting whether a 3rd gear shift fork is in place; if no, entering step S4. S3: performing 3rd gear downshift, and detecting whether an unexecutable condition occurs; if no, detecting whether the 3rd gear downshift is completed; if yes, entering step S4. S4: performing odd clutch combination, and detecting whether an unexecutable condition occurs; if no, detecting whether a 1st gear mounting condition is satisfied; if yes, entering step S5, if no, returning to step S4. S5: performing odd clutch opening, and detecting whether an unexecutable condition occurs; if no, judging whether the odd clutch is opened; if no, returning to step S5, if yes, performing 1st gear mounting. The noise, vibration and harshness and driving smoothness during the brake shift 1st gear are improved.

Description

Technical Field

[0001] This invention relates to the automotive field, specifically a shift control method for a dual-clutch transmission. Background Technology

[0002] Dual-clutch transmissions (DCTs) are a type of automatic transmission that has gained increasing popularity among domestic and international automakers in recent years. Compared to other types of automatic transmissions, DCTs offer advantages such as uninterrupted power delivery during gear shifts, superior shift quality, and high transmission efficiency, making them one of the most popular automatic transmissions currently available. They are widely used not only in traditional internal combustion engine vehicles but also in various hybrid vehicle configurations.

[0003] Noise issues when shifting into first gear under braking conditions and the smoothness of accelerator pedal operation during first gear shifting (in urban traffic congestion) have always been pain points for DCTs.

[0004] 1. Noise issue when shifting into first gear while braking

[0005] Under braking conditions, the existing technology directly engages 1st gear based on the gear shift diagram or pre-engaged gear. When engaging 1st gear, the odd-numbered shaft has two states (the odd-numbered input shaft speed is N1, and the target shaft speed for 1st gear (output shaft speed multiplied by the 1st gear ratio) is n1):

[0006] (1) When the 3rd gear shift fork is in position, the axial speed of the odd-numbered shafts is maintained at the 3rd gear ratio. Since the 3rd gear ratio is less than the 1st gear ratio, N1 must be less than n1.

[0007] (2) When the 3rd gear shift fork is not in position, the odd-numbered shaft shift fork is in a disengaged state. At this time, the speed of the odd-numbered input shaft is uncontrollable. However, due to the influence of the shaft system drag torque, the speed of the odd-numbered input shaft will gradually decrease. In severe cases, it will drop to near 0. There is also a situation where N1 is less than n1.

[0008] Assume the speed at the input shaft end of the first gear synchronizer is ω l The output shaft speed is ω o At the synchronous speed difference Δω=ω l -ω o After the speed difference between the two ends of the synchronizer reaches zero, the gear sleeve passes through the synchronizer ring and enters the free sliding stage until it meshes with the gear hub, and the gear engagement process ends.

[0009] like Figure 1 As shown, since N1 is less than n1, during the synchronization process of shifting into first gear (t1-t2 stage), the acceleration w of the odd-numbered input shaft is... l ' is positive. After synchronization is completed in 1st gear (t2-t3 stage), due to inertia, during the free coasting stage, the speed at the synchronizer input shaft end is ω. l It will accelerate briefly, while the output shaft speed ω c Continue deceleration (during braking, the output shaft acceleration w)o (negative), resulting in a synchronization speed difference Δω=ω at the moment of gear engagement. l -ω o The changes are significant, resulting in a knocking noise from the gears.

[0010] 2. Smoothness of accelerator pedal operation when shifting into first gear

[0011] If the driver suddenly releases the brake during the braking and shifting into first gear, before the first gear synchronization phase is complete, it will cause the output shaft end acceleration w during the free-coasting phase after synchronization is completed. o A sudden change occurs, producing a grinding noise. If the driver not only releases the brake but also presses the accelerator, the gear will first downshift from 2nd to 1st, and then immediately upshift from 1st to 2nd, resulting in frequent gear changes in a short period of time. This affects driving smoothness, and the problem is exacerbated in congested traffic. Summary of the Invention

[0012] The purpose of this invention is to overcome the above-mentioned defects in the prior art and provide a shift control method for a dual-clutch transmission. Before the odd-numbered shaft of the clutch and the synchronizer input shaft complete engagement, a pre-control condition including engaging first gear and disengaging from third gear is added. This ensures that when shifting to first gear, the rotational speeds of both the odd-numbered shaft of the clutch and the synchronizer input shaft are decelerating, reducing the speed difference. This significantly improves the noise, vibration, and acoustic roughness of engaging first gear under braking conditions. In one embodiment, the addition of a first-gear disengagement operation significantly improves the problem of poor smoothness caused by frequent gear switching between first and second gear in congested conditions.

[0013] This invention provides a shift control method for a dual-clutch transmission, comprising the following steps:

[0014] S1: Detect whether the car meets the conditions for enabling 1st gear shifting;

[0015] If so, proceed to step S2;

[0016] If not, continue to check whether the car meets the conditions for enabling 1st gear shift;

[0017] S2: Check if the 3rd gear shift fork is in position;

[0018] If yes, proceed to step S3; otherwise, proceed to step S4.

[0019] S3: Execute 3rd gear downshift and check if any unexecution conditions occur;

[0020] If yes, return to the initial state; if no, check if downshifting from 3rd gear is complete; if no, return to step S3; if yes, proceed to step S4.

[0021] S4: Engage the odd-numbered clutches and check for any unexecutable conditions;

[0022] If yes, return to the initial state; if no, check if the condition for shifting to 1st gear is met; if yes, proceed to step S5; if no, return to step S4.

[0023] S5: Execute the odd-numbered clutches to open and check for any unexecution conditions;

[0024] If yes, return to the initial state; if no, determine whether the odd-numbered clutches are open; if no, return to step S5; if yes, proceed to step S6.

[0025] S6: Engage 1st gear;

[0026] Among them, the conditions that cannot be executed include throttle being greater than the first throttle threshold or the target gear being greater than the third gear.

[0027] Using the above scheme, both the synchronizer input shaft and the odd-numbered shaft are in a deceleration process during the speed synchronization phase. This is consistent with the continued deceleration trend of the output shaft speed of the gearbox during braking, thereby reducing the synchronization speed difference at the moment of gear engagement. This significantly improves the noise, vibration and acoustic roughness of the vehicle when shifting into first gear under braking conditions, and can effectively improve the noise, vibration and acoustic roughness of the vehicle under certain operating conditions.

[0028] According to another specific embodiment of the present invention, a shift control method for a dual-clutch transmission disclosed in this embodiment includes the following step S1: determining whether the first gear shift enable is satisfied.

[0029] S1-a: Detects whether the vehicle speed is greater than the first speed threshold and whether the 1st gear shift fork is not in position;

[0030] If so, proceed to step S1-b;

[0031] If not, return to the initial state;

[0032] S1-b: Detect whether the throttle is less than the second throttle threshold and whether the driving gear and the target gear are both 2nd gear;

[0033] If so, proceed to step S2;

[0034] If not, restart step S1-b.

[0035] By adopting the above scheme, it is ensured that the 1st gear shift fork and the vehicle speed can start the shifting operation before shifting to 1st gear, and that the dual-clutch shifts from 2nd gear to 1st gear, reducing interference with normal operating conditions, which can be used as a condition for accurately identifying this operating condition.

[0036] According to another specific embodiment of the present invention, an embodiment of the present invention discloses a shift control method for a dual-clutch transmission, wherein the first vehicle speed threshold is 1 to 10 kph and the second throttle threshold is 1% to 5%.

[0037] According to another specific embodiment of the present invention, a shift control method for a dual-clutch transmission is disclosed in the present invention. In step S4, the condition for engaging first gear is that the rotational speed of the odd-numbered shaft is greater than the output shaft speed multiplied by the first gear ratio, and the vehicle speed is less than a second vehicle speed threshold.

[0038] Using the above scheme, the condition for engaging first gear is that the speed of the odd-numbered shaft is greater than the output shaft speed multiplied by the first gear ratio. The odd-numbered shaft speed is made greater than the target input shaft speed of first gear before the odd-numbered clutch is engaged. During the synchronization of the odd-numbered shaft and the intermediate shaft speed, both the master and slave ends of the synchronizer are in a deceleration process.

[0039] According to another specific embodiment of the present invention, an embodiment of the present invention discloses a shift control method for a dual-clutch transmission, wherein the second vehicle speed threshold is 1 to 10 kph.

[0040] According to another specific embodiment of the present invention, a shift control method for a dual-clutch transmission is disclosed in the present invention. In step S5, the odd clutch is detected and determined whether the odd clutch is open based on whether the pressure of the odd clutch is less than a pressure threshold. If it is less than the pressure threshold, the odd clutch is open; if it is not less than the pressure threshold, the odd clutch is not open. The pressure threshold is 50 to 100 Cbar.

[0041] Using the above method, with a pressure threshold of 50-100 Cbar as the standard, it is possible to accurately determine whether the clutch is engaged.

[0042] According to another specific embodiment of the present invention, a shift control method for a dual-clutch transmission disclosed in this embodiment further includes the following steps after step S6:

[0043] S7: Check if the conditions for downshifting from 1st gear are met. The conditions for downshifting from 1st gear are releasing the brake or pressing the accelerator.

[0044] If so, proceed to step S8;

[0045] If not, check if 1st gear is engaged; if yes, return to the initial state; if no, return to step S6.

[0046] Step S8: Execute 1st gear downshift.

[0047] Using the above scheme, if the driver suddenly releases the brake or not only releases the brake but also presses the accelerator at any moment during the shift to first gear, the first gear will be downshifted. This avoids the noise that occurs when the first gear synchronization phase is not completed during the braking and shifting to first gear and the acceleration at the output shaft end suddenly changes during the free coasting phase. It also significantly improves the problem of poor smoothness caused by frequent shifting between first and second gear in congested conditions.

[0048] According to another specific embodiment of the present invention, a shift control method for a dual-clutch transmission is disclosed in the present invention. In step S7, if the throttle is greater than a first throttle threshold, it is determined that the throttle is being pressed; if the brake is less than a brake threshold, it is determined that the brake is being released. The first throttle threshold is 1% to 5%, and the brake threshold is 1% to 5%.

[0049] According to another specific embodiment of the present invention, a shift control method for a dual-clutch transmission disclosed in this embodiment further includes the following steps after step S8:

[0050] Check if the downshift from 1st gear is complete;

[0051] If so, return to the initial state;

[0052] If not, return to step S8.

[0053] Using the above method, check whether the first gear downshift is completed to ensure that the first gear downshift is completed smoothly.

[0054] The beneficial effects of this invention are:

[0055] Both the synchronizer input shaft and the odd-numbered shafts are in a deceleration process during the speed synchronization phase, which is consistent with the continued deceleration trend of the transmission output shaft during braking. This reduces the synchronization speed difference at the moment of gear engagement, significantly improving the noise, vibration, and acoustic roughness of shifting into first gear under braking conditions. It can effectively improve the noise, vibration, and acoustic roughness of the vehicle under certain operating conditions. At the same time, if the driver suddenly releases the brake or not only releases the brake but also presses the accelerator during the first gear shift, the first gear will be downshifted. This avoids noise caused by the sudden change in acceleration at the output shaft end during the free-coasting phase when the first gear synchronization phase is not yet completed during braking and shifting into first gear. It also significantly improves the problem of poor smoothness caused by frequent gear switching between first and second gear in congested conditions. Attached Figure Description

[0056] Figure 1 This is a schematic diagram of the gear shifting problem in the prior art;

[0057] Figure 2 This is a control flow block diagram of a shift control method for a dual-clutch transmission in one embodiment of the present invention.

[0058] Figure 3 This is a diagram illustrating the effect of a shift control method for a dual-clutch transmission in one embodiment of the present invention.

[0059] Figure 4 This is a control flow block diagram of a shift control method for a dual-clutch transmission in another embodiment of the present invention.

[0060] Figure 5 This is a diagram illustrating the effect of a shift control method for a dual-clutch transmission according to another embodiment of the present invention. Detailed Implementation

[0061] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Although the description of the present invention is presented in conjunction with preferred embodiments, this does not mean that the features of the invention are limited to these embodiments. On the contrary, the purpose of describing the invention in conjunction with embodiments is to cover other options or modifications that may be derived based on the claims of the present invention. To provide a deep understanding of the invention, many specific details will be included in the following description. The invention may also be implemented without using these details. Furthermore, to avoid confusion or obscuring the focus of the invention, some specific details will be omitted in the description. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0062] It should be noted that in this specification, similar reference numerals and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0063] In the description of this embodiment, it should be noted that the terms "upper", "lower", "inner", "bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship that the product of the invention is usually placed in during use. They are only for the convenience of describing the present invention and simplifying the description, 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 limiting the present invention.

[0064] The terms “first”, “second”, etc., are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0065] In the description of this embodiment, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set up," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; 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; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this embodiment based on the specific circumstances.

[0066] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0067] Example

[0068] A shift control method for a dual-clutch transmission, such as Figure 2 As shown, it includes the following steps:

[0069] S1: Detect whether the car meets the conditions for enabling 1st gear shifting;

[0070] If so, proceed to step S2;

[0071] If not, continue to check whether the car meets the conditions for enabling 1st gear shift;

[0072] S2: Check if the 3rd gear shift fork is in position;

[0073] If yes, proceed to step S3; otherwise, proceed to step S4.

[0074] S3: Execute 3rd gear downshift and check if any unexecution conditions occur;

[0075] If yes, return to the initial state; if no, check if downshifting from 3rd gear is complete; if no, return to step S3; if yes, proceed to step S4.

[0076] S4: Engage the odd-numbered clutches and check for any unexecutable conditions;

[0077] If yes, return to the initial state; if no, check if the condition for shifting to 1st gear is met; if yes, proceed to step S5; if no, return to step S4.

[0078] S5: Execute the odd-numbered clutches to open and check for any unexecution conditions;

[0079] If yes, return to the initial state; if no, determine whether the odd-numbered clutches are open; if no, return to step S5; if yes, proceed to step S6.

[0080] S6: Engage 1st gear;

[0081] Among them, the conditions that cannot be executed include throttle being greater than the first throttle threshold or the target gear being greater than the third gear.

[0082] It is important to understand that the "initial state" refers to the start state of the detection process, that is, the initial state when the car is coasting or stopped, and the shift control method for the dual-clutch transmission provided in this embodiment is activated by engaging first gear. The odd-numbered shaft is the input shaft of the clutch responsible for odd-numbered gears. Shifting is completed when the synchronizer input shaft engages with the odd-numbered input shaft, at which point N1 and n1 are synchronized. Furthermore, the output shaft is the output shaft of the transmission.

[0083] In addition, regarding the conditions under which the action is not possible, pressing the accelerator or targeting a gear higher than 3rd gear indicates a change in driving intent, and it is no longer appropriate to engage 1st gear at this time, so the action should be disengaged directly.

[0084] Specifically, the above control method can achieve first gear pre-engagement under braking conditions, i.e. Figure 2 and Figure 3 As shown, in steps S1-S3, the 3rd gear shift fork is first deactivated. Then, based on the 3rd gear shift fork being deactivated, step S4 imposes restrictions on engaging 1st gear. Since the clutch needs to be disengaged before shifting, a check is performed to determine if the conditions for engaging 1st gear are met before disengaging the clutch. The process corresponding to step S4 is described in... Figure 3 This is manifested in the following way: at time t0, the target gear changes to 1st gear; prior to this, preparations for engaging 1st gear are completed during the t-1 to t0 phase. In step S5, the clutch is disengaged to separate the odd-numbered shaft from the output shaft. Figure 3 In the process, this is manifested as disengaging the clutch and setting the target gear to 1st gear at t0. Engaging 1st gear begins at S6.

[0085] like Figure 3 As shown in the figure, the horizontal axis represents time, and the vertical axis represents the values ​​corresponding to each function curve. The function curves in the figure, from top to bottom, represent the target shaft speed n1 in first gear, the odd shaft speed N1, the shift fork position, the odd clutch pressure, and the target gear.

[0086] For example, if the condition for engaging first gear is that the speed of the odd-numbered shafts is greater than the target input shaft speed for first gear during the t-1 to t0 phase (calculated based on the output shaft speed and the first gear ratio), then the speed of the odd-numbered shafts is pre-set to be greater than the target input shaft speed for first gear during the t-1 to t0 phase, and the speed stabilizes during the t0 to t1 phase. In other words, the speed difference between the master and slave ends of the first gear synchronizer is synchronized within the time period t1 to t2. During this time interval, the speeds of both ends of the synchronizer are in a deceleration process, which is consistent with the continued deceleration trend of the output shaft speed during braking. This reduces the synchronization speed difference at the moment of gear engagement. Therefore, the speed reduction of the odd-numbered shafts during the synchronization phase t1 to t2 effectively avoids gear knocking noise caused by excessive synchronization speed difference at the moment of gear engagement, significantly improving the noise, vibration, and acoustic roughness of engaging first gear under braking conditions.

[0087] According to another specific embodiment of the present invention, an embodiment of the present invention discloses a shift control method for a dual-clutch transmission, such as... Figure 4 As shown, the steps in step S1 to determine whether the first gear shift enable is satisfied include:

[0088] S1-a: Detects whether the vehicle speed is greater than the first speed threshold and whether the 1st gear shift fork is not in position;

[0089] If so, proceed to step S1-b;

[0090] If not, return to the initial state;

[0091] S1-b: Detect whether the throttle is less than the second throttle threshold and whether the driving gear and the target gear are both 2nd gear;

[0092] If so, proceed to step S2;

[0093] If not, restart step S1-b.

[0094] It should be understood that the first throttle threshold is the throttle state when the accelerator is pressed, and the second throttle threshold is the throttle state when the accelerator is released and the brake is applied. The specific throttle threshold can be set by those skilled in the art based on the throttle control sensitivity. The first throttle threshold and the second throttle threshold have different meanings and are not related. Those skilled in the art can set two different thresholds within a certain range, or they can set them to thresholds that are numerically equal.

[0095] By adopting the above scheme, it is ensured that the 1st gear shift fork and the vehicle speed can start the shifting operation before shifting to 1st gear, and that the dual-clutch shifts from 2nd gear to 1st gear, reducing interference with normal operating conditions, which can be used as a condition for accurately identifying this operating condition.

[0096] According to another specific embodiment of the present invention, an embodiment of the present invention discloses a shift control method for a dual-clutch transmission, wherein the first vehicle speed threshold is 1 to 10 kph and the second throttle threshold is 1% to 5%.

[0097] It should be understood that the range of values ​​for the first throttle threshold and the second throttle threshold can be the same or different. When the range of values ​​for the two are the same, those skilled in the art can still set two different thresholds within that range, and the two are unrelated.

[0098] According to another specific embodiment of the present invention, a shift control method for a dual-clutch transmission is disclosed in the present invention. In step S4, the condition for engaging first gear is that the rotational speed of the odd-numbered shaft is greater than the output shaft speed multiplied by the first gear ratio, and the vehicle speed is less than a second vehicle speed threshold.

[0099] Specifically, the odd-numbered shaft is the input shaft of the clutch responsible for odd-numbered gears. The shift is completed when the synchronizer input shaft engages with the odd-numbered input shaft. At this time, N1 and n1 are synchronized. In addition, the output shaft is the output shaft of the gearbox.

[0100] Using the above scheme, the condition for engaging first gear is that the speed of the odd-numbered shaft is greater than the output shaft speed multiplied by the first gear ratio. The odd-numbered shaft speed is made greater than the target input shaft speed of first gear before the odd-numbered clutch is engaged. During the synchronization of the odd-numbered shaft and the intermediate shaft speed, both the master and slave ends of the synchronizer are in a deceleration process.

[0101] According to another specific embodiment of the present invention, an embodiment of the present invention discloses a shift control method for a dual-clutch transmission, wherein the second vehicle speed threshold is 1 to 10 kph.

[0102] It is important to understand that although the first speed threshold and the second speed threshold have the same range, they can be set to different thresholds, and there is no correlation between their magnitudes.

[0103] According to another specific embodiment of the present invention, a shift control method for a dual-clutch transmission is disclosed in the present invention. In step S5, the odd clutch is detected and determined whether the odd clutch is open based on whether the pressure of the odd clutch is less than a pressure threshold. If it is less than the pressure threshold, the odd clutch is open; if it is not less than the pressure threshold, the odd clutch is not open. The pressure threshold is 50 to 100 Cbar.

[0104] It's important to understand that, under normal circumstances, the torque transmitted by the corresponding clutch must be less than a certain value before shifting gears. If this value is exceeded, it will increase the synchronizing torque during shifting, and in severe cases, synchronization may fail, ultimately leading to gear shifting failure. Therefore, the system is set to only engage first gear when the pressure of an odd-numbered clutch is below a pressure threshold.

[0105] Using the above method, with a pressure threshold of 50-100 Cbar as the standard, it is possible to accurately determine whether the clutch is engaged.

[0106] According to another specific embodiment of the present invention, an embodiment of the present invention discloses a shift control method for a dual-clutch transmission, such as... Figure 4 As shown, the following steps follow step S6:

[0107] S7: Check if the conditions for downshifting from 1st gear are met. The conditions for downshifting from 1st gear are releasing the brake or pressing the accelerator.

[0108] If so, proceed to step S8;

[0109] If not, check if 1st gear is engaged; if yes, return to the initial state; if no, return to step S6.

[0110] Step S8: Execute 1st gear downshift.

[0111] Specifically, such as Figure 5 As shown, the shift to 1st gear begins at t0. If the driver suddenly releases the brake or not only releases the brake but also presses the accelerator at any moment during this process, the 1st gear will be downshifted. This is to avoid the 1st gear synchronization phase not being completed during the braking and shifting to 1st gear, which would cause a sudden change in the acceleration at the output shaft end during the free coasting phase after synchronization is completed. This would cause the synchronization speed difference to regenerate at the moment of gear engagement, resulting in noise and affecting driving smoothness.

[0112] According to another specific embodiment of the present invention, a shift control method for a dual-clutch transmission is disclosed in the present invention. In step S7, if the throttle is greater than a first throttle threshold, it is determined that the throttle is being pressed; if the brake is less than a brake threshold, it is determined that the brake is being released. The first throttle threshold is 1% to 5%, and the brake threshold is 1% to 5%.

[0113] According to another specific embodiment of the present invention, an embodiment of the present invention discloses a shift control method for a dual-clutch transmission, such as... Figure 4 As shown, after step S8, the following steps are also included:

[0114] Check if the downshift from 1st gear is complete;

[0115] If so, return to the initial state;

[0116] If not, return to step S8.

[0117] Using the above method, check whether the first gear downshift is completed to ensure that the first gear downshift is completed smoothly.

[0118] While the present invention has been illustrated and described with reference to certain preferred embodiments, those skilled in the art should understand that the above description is a further detailed explanation of the invention in conjunction with specific embodiments, and should not be construed as limiting the specific implementation of the invention to these descriptions. Various changes in form and detail can be made by those skilled in the art, including several simple deductions or substitutions, without departing from the spirit and scope of the invention.

Claims

1. A shift control method for a dual-clutch transmission, characterized in that, Includes the following steps: S1: Detect whether the car meets the conditions for enabling 1st gear shifting; If so, proceed to step S2; If not, continue to check whether the car meets the conditions for enabling 1st gear shift; S2: Check if the 3rd gear shift fork is in position; If so, proceed to step S3; If not, proceed to step S4; S3: Execute 3rd gear downshift and check if any unexecution conditions occur; If so, return to the initial state; If not, check if downshifting from 3rd gear is complete; if not, return to step S3; if yes, proceed to step S4. S4: Engage the odd-numbered clutches and check for any unexecutable conditions; If so, return to the initial state; If not, check if the condition for engaging 1st gear is met; if yes, proceed to step S5; if no, return to step S4. S5: Execute the odd-numbered clutches to open and check for any unexecution conditions; If so, return to the initial state; If not, determine whether the odd-numbered clutches are engaged; if not, return to step S5; if yes, proceed to step S6. S6: Engage 1st gear; The unexecutable conditions include throttle exceeding the first throttle threshold or the target gear being greater than 3.

2. The shift control method for a dual-clutch transmission according to claim 1, characterized in that, The determination step in step S1 to determine whether the first gear shift enable is satisfied includes: S1-a: Detects whether the vehicle speed is greater than the first speed threshold and whether the 1st gear shift fork is not in position; If so, proceed to step S1-b; If not, return to the initial state; S1-b: Detect whether the throttle is less than the second throttle threshold and whether the driving gear and the target gear are both 2nd gear; If so, proceed to step S2; If not, restart step S1-b.

3. The shift control method for a dual-clutch transmission according to claim 2, characterized in that, The first vehicle speed threshold is a value in the range of 1 to 10 kph, and the second throttle threshold is a value in the range of 1% to 5%.

4. The shift control method for a dual-clutch transmission according to claim 1, characterized in that, In step S4, the condition for engaging first gear is that the rotational speed of the odd-numbered shaft is greater than the output shaft speed multiplied by the first gear ratio, and the vehicle speed is less than the second vehicle speed threshold.

5. The shift control method for a dual-clutch transmission according to claim 4, characterized in that, The second vehicle speed threshold is a value in the range of 1 to 10 kph.

6. The shift control method for a dual-clutch transmission according to claim 1, characterized in that, In step S5, the odd clutch is detected and determined to be open based on whether the odd clutch pressure is less than the pressure threshold. If it is less than the pressure threshold, the odd clutch is open; if it is not less than the pressure threshold, the odd clutch is not open. The pressure threshold is a value in the range of 50 to 100 cbar.

7. The shift control method for a dual-clutch transmission according to claim 1, characterized in that, The process after step S6 also includes: S7: Detect whether the conditions for downshifting from 1st gear are met, wherein the conditions for downshifting from 1st gear are releasing the brake or pressing the accelerator. If so, proceed to step S8; If not, check if 1st gear is engaged; if yes, return to the initial state; if no, return to step S6. Step S8: Execute 1st gear downshift.

8. The shift control method for a dual-clutch transmission according to claim 7, characterized in that, In step S7, if the throttle is greater than the first throttle threshold, it is determined that the throttle is being pressed; if the brake is less than the brake threshold, it is determined that the brake is being released. The first throttle threshold is a value in the range of 1% to 5%, and the brake threshold is a value in the range of 1% to 5%.

9. The shift control method for a dual-clutch transmission according to claim 8, characterized in that, Following step S8, the following steps are also included: Check if the downshift from 1st gear is complete; If so, return to the initial state; If not, return to step S8.

Images