Lowest vehicle speed without synchronizer gear shift control method, device and automobile

Abstract

A kind of extremely low vehicle speed synchronizer gear position gear engagement control method, device and car, the extremely low vehicle speed synchronizer gear position gear engagement control method includes: judging whether the gear engagement of main box of gearbox occurs to tooth;If yes, then control the empty gear of main box of gearbox, and the way of segmented control is used to control clutch slowly combined, to drive intermediate shaft slowly rotate;Judging whether the rotational speed of intermediate shaft reaches the threshold range set;If yes, then control clutch is separated for a predetermined time, and then re-control main box of gearbox to execute gear engagement action;Otherwise, continue to wait for clutch to bring the rotational speed of intermediate shaft to threshold range.The time of clutch separation is controlled, and gear engagement action is executed after clutch separation reaches the predetermined time, can reserve time for the separation of clutch, when main box of gearbox executes gear engagement action, clutch can be separated to a certain extent, gear shifting impact can be avoided, solve the technical problem of obvious gear engagement impact caused after tooth.

Description

Technical Field

[0001] This application relates to the field of gear shifting control for heavy-duty AMT commercial vehicles, specifically to a method, device, and vehicle for gear shifting control without a synchronizer at extremely low vehicle speeds. Background Technology

[0002] Currently, the synchronizerless shifting technology for main gearboxes is widely used in the AMT (Automated Manual Transmission) field of commercial vehicles. In related technologies, the synchronizerless shifting sequence for heavy-duty AMT commercial vehicles at extremely low speeds is as follows: clutch disengagement—main gearbox disengagement—auxiliary gearbox engagement—main gearbox gear speed adjustment (via intermediate shaft brake or clutch)—intermediate shaft brake disengagement / clutch disengagement—main gearbox engagement. If the main gearbox engagement gears are misaligned, a new shifting strategy is executed, with the following sequence: main gearbox disengagement—main gearbox gear speed adjustment—main gearbox engagement. This involves three processes: when the clutch engagement depth is deep, the transmission actuator is directly controlled to perform the shifting action, repeating the above actions until successful engagement.

[0003] In the above-mentioned gear shifting scheme, the shifting timing has no adverse effects as long as the gearbox master gear does not engage. However, based on experience, gearboxes without a synchronizer in the master gear have a higher probability of gear engagement when shifting at low speeds or when stationary (actual vehicle data shows it to be around 50%). The above-mentioned gear shifting scheme will cause obvious shifting shock because it adopts a strategy of maintaining clutch engagement and directly shifting gears after gear engagement occurs. At low speeds, this manifests as a noticeable shifting shock or even gear grinding, which can damage the gearbox gears. At stationary conditions, it manifests as severe shaking of the cab. In scenarios that require frequent DNR or RND operations, such as reversing into a parking space or unloading cargo, this is more likely to cause user complaints.

[0004] Therefore, it is necessary to design a new method for controlling gear shifting without a synchronizer at extremely low vehicle speeds to overcome the above problems. Summary of the Invention

[0005] This application provides a method, device, and automobile for controlling gear shifting without synchronizer at extremely low vehicle speeds, which can solve the technical problem in related technologies where the strategy of maintaining clutch engagement and directly shifting gears after gear engagement causes significant shifting shock.

[0006] In a first aspect, embodiments of this application provide a method for controlling gear shifting without a synchronizer at extremely low vehicle speeds, the method comprising:

[0007] Determine if gear misalignment occurs during gear shifting in the main gearbox;

[0008] If so, the transmission master gearbox is switched to neutral, and when the speed of the transmission intermediate shaft reaches the set threshold range, the clutch is disengaged for a preset time before the transmission master gearbox is re-engaged.

[0009] In conjunction with the first aspect, in one embodiment, controlling the transmission master gearbox to disengage into neutral, and when the rotational speed of the transmission intermediate shaft reaches a set threshold range, controlling the clutch to disengage for a preset time before re-controlling the transmission master gearbox to perform a gear engagement action, includes:

[0010] The main gearbox is shifted to neutral, and the clutch is engaged slowly using a segmented control method to drive the intermediate shaft to rotate slowly.

[0011] Determine whether the rotational speed of the intermediate shaft has reached the set threshold range;

[0012] If so, the clutch will disengage for a preset time before the transmission master gearbox is re-controlled to perform the gear shifting action;

[0013] Otherwise, continue to wait for the clutch to bring the intermediate shaft speed to the threshold range.

[0014] In conjunction with the first aspect, in one embodiment, the method of controlling the clutch to engage slowly by segmented control includes: first, quickly engaging the clutch to a first position, and then controlling the clutch to engage slowly at a certain slope M.

[0015] In conjunction with the first aspect, in one embodiment, controlling the gearbox masterbox to perform the gear shifting action again after a preset time of clutch disengagement includes:

[0016] Control the clutch to disengage and determine whether the time of issuing the command to control the clutch to disengage has reached the set time threshold;

[0017] If so, the master gearbox will be re-controlled to perform the gear shifting action; otherwise, continue to wait until the time it takes for the command to disengage the clutch reaches the set time threshold.

[0018] In conjunction with the first aspect, in one embodiment, before determining whether gear engagement in the transmission master gearbox has occurred, the method further includes:

[0019] When it is determined that the vehicle is in a low-speed / stationary gear-shifting condition, the clutch is disengaged and the transmission master set is disconnected.

[0020] Control the speed regulation of the main gearbox gear;

[0021] The transmission master gearbox is controlled to perform gear shifting actions, and the clutch is slowly engaged using a segmented control method.

[0022] In conjunction with the first aspect, in one embodiment, prior to the control of the main gearbox gear speed regulation, the method further includes:

[0023] Determine whether the auxiliary gearbox needs to be activated based on the target gear and the vehicle's current gear status;

[0024] If the auxiliary gearbox needs to be activated, control the auxiliary gearbox to engage the appropriate position.

[0025] In conjunction with the first aspect, in one embodiment, the control of the speed regulation of the main gearbox gear includes:

[0026] Calculate the speed difference between the target gear and the current gear based on the rotational speeds of the intermediate shaft and main shaft of the gearbox;

[0027] Determine whether the speed difference is within the set threshold range;

[0028] If so, the main gearbox is controlled to engage the gear; otherwise, the intermediate shaft brake or clutch is controlled to adjust the speed.

[0029] In conjunction with the first aspect, in one embodiment, the extremely low vehicle speed gear shifting control method without synchronizer further includes:

[0030] The vehicle's operating status is determined by real-time monitoring of the transmission output shaft speed. When the vehicle rolls backward or the rate of decrease in output shaft speed is less than a preset value during transmission shifting, the transmission shifting speed difference threshold is increased.

[0031] Secondly, this application provides an ultra-low speed gear shifting control device without synchronizer. The ultra-low speed gear shifting control device without synchronizer includes: an automatic transmission control unit, which is used to determine whether gear engagement of the transmission master gearbox has occurred; the automatic transmission control unit is also used to control the transmission master gearbox to shift to neutral when gear engagement of the transmission master gearbox has occurred, and when the rotational speed of the transmission intermediate shaft reaches a set threshold range, control the clutch to disengage for a preset time before re-controlling the transmission master gearbox to perform the gear engagement action.

[0032] Thirdly, embodiments of this application provide a vehicle that includes the aforementioned extremely low speed gear shifting control device without synchronizer.

[0033] The beneficial effects of the technical solutions provided in this application include at least the following:

[0034] By controlling the clutch disengagement time, the gear shifting action is performed only after the clutch disengagement reaches a preset time. This allows time for clutch disengagement, ensuring that the clutch disengages to a certain extent when the transmission master gearbox performs the gear shifting action. This avoids shifting shock and solves the technical problem in related technologies where the strategy of maintaining clutch engagement and directly shifting gears after gear engagement causes significant shifting shock. Attached Figure Description

[0035] Figure 1 This is a flowchart illustrating an embodiment of the synchronizer-free gear shifting control method for extremely low vehicle speeds according to this application.

[0036] Figure 2 This is a flowchart illustrating another embodiment of the synchronizing-free gear shifting control method for extremely low vehicle speeds in this application.

[0037] Figure 3 This is a diagram illustrating the gear shifting timing of a transmission main gearbox according to this application. Detailed Implementation

[0038] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0039] The terms "comprising" and "having," and any variations thereof, in the specification, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus. The terms "first," "second," and "third," etc., are used to distinguish different objects, etc., and do not indicate a sequence, nor do they limit "first," "second," and "third" to different types.

[0040] In the description of the embodiments of this application, terms such as "exemplary," "for example," or "for instance" are used to indicate examples, illustrations, or explanations. Any embodiment or design described as "exemplary," "for example," or "for instance" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary," "for example," or "for instance" is intended to present the relevant concepts in a concrete manner.

[0041] In the description of the embodiments of this application, unless otherwise stated, " / " means "or". For example, A / B can mean A or B. The "and / or" in the text is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. In addition, in the description of the embodiments of this application, "multiple" means two or more.

[0042] In some processes described in the embodiments of this application, multiple operations or steps are included in a specific order. However, it should be understood that these operations or steps may not be executed in the order they appear in the embodiments of this application, or they may be executed in parallel. The sequence number of the operation is only used to distinguish different operations, and the sequence number itself does not represent any execution order. In addition, these processes may include more or fewer operations, and these operations or steps may be executed sequentially or in parallel, and these operations or steps may be combined.

[0043] First, some of the technical terms used in this application will be explained to help those skilled in the art understand this application.

[0044] AMT: Automatic Mechanical Transmission.

[0045] TCU: Transmission Control Unit, automatic transmission control unit.

[0046] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0047] In a first aspect, embodiments of this application provide a method for controlling gear shifting without a synchronizer at extremely low vehicle speeds.

[0048] In one embodiment, reference is made to Figure 1 , Figure 1 This is a flowchart illustrating the first embodiment of the ultra-low speed gear shifting control method without a synchronizer according to this application. Figure 1 As shown, the method for controlling gear shifting without a synchronizer at extremely low vehicle speeds includes:

[0049] S1: Determine if gear misalignment occurs during gear shifting in the main gearbox.

[0050] S2: If so, the transmission master gearbox is shifted to neutral, and when the speed of the transmission intermediate shaft reaches a set threshold range, the clutch is disengaged for a preset time before the transmission master gearbox is re-engaged. In other words, in this embodiment, when gear engagement is detected as gear misalignment in the transmission master gearbox, gear engagement is not performed directly. Instead, the clutch is disengaged first, and the clutch disengagement time is ensured to reach a preset time before the transmission master gearbox is re-engaged. This preset time can be calibrated.

[0051] In this embodiment, the TCU can control the gearbox shifting. If the shifting action fails to engage the target gear due to issues such as gear misalignment, the TCU needs to first control the gearbox actuator to shift the main gearbox to neutral to separate the gears. The TCU can control the clutch actuator to disengage the clutch once the intermediate shaft speed reaches a certain value as determined by the speed sensor.

[0052] In this embodiment, by controlling the clutch disengagement time, the gear shifting action is performed only after the clutch disengagement reaches a preset time, rather than immediately after disengagement. This allows time for clutch disengagement, ensuring that the clutch disengages to a certain extent when the transmission master gearbox performs the gear shifting action. This avoids shifting shock at extremely low vehicle speeds and saves shifting time to some extent. It solves the technical problem in related technologies where the strategy of maintaining clutch engagement and directly shifting gears after gear engagement causes significant shifting shock.

[0053] After step S2, the TCU controls the transmission actuator to successfully engage the transmission into the target gear, which completes the gear engagement. After the gear engagement is completed, a disengagement command is simultaneously issued to the clutch to ensure that the clutch is in a disengaged state after the gear is engaged.

[0054] Furthermore, in one embodiment, see... Figure 2 As shown, in step S2, controlling the transmission master gearbox to shift to neutral, and when the rotational speed of the transmission intermediate shaft reaches a set threshold range, controlling the clutch to disengage for a preset time before re-controlling the transmission master gearbox to perform the gear engagement action, may include:

[0055] S21: Control the main gearbox to shift to neutral, and use segmented control to slowly engage the clutch, thereby driving the intermediate shaft to rotate slowly. In this embodiment, during the process of controlling the main gearbox to shift to neutral, the TCU can continuously use segmented control to control the clutch actuator to slowly engage the clutch, thereby driving the intermediate shaft to rotate slowly.

[0056] S21: Determine whether the rotational speed of the intermediate shaft has reached the set threshold range. The TCU can determine whether the rotational speed of the intermediate shaft has reached the set threshold range through a speed sensor.

[0057] S23: If yes, then control the clutch to disengage for a preset time before re-controlling the transmission master gearbox to perform the gear shifting action; otherwise, continue to wait for the clutch to bring the intermediate shaft speed to the threshold range before re-controlling the transmission master gearbox to perform the gear shifting action.

[0058] In this embodiment, by using segmented control to control the clutch to engage slowly, the intermediate shaft can be driven to rotate slowly. The segmented control method of the clutch is more precise and can effectively avoid the waste of shifting time caused by excessive clutch engagement due to insufficient clutch control precision or mechanical differences.

[0059] By controlling the clutch engagement process through segmented control, it is possible to effectively prevent the intermediate shaft speed from being driven too high due to clutch overshoot (that is, the clutch is engaged too deeply). (If the intermediate shaft speed is driven too high, the intermediate shaft brake needs to be controlled to reduce the speed, which wastes time.) This would lead to increased shifting time and shifting shock (over-engaged clutch would also cause shock when shifting gears later).

[0060] Furthermore, in one embodiment, the segmented control method for slowly engaging the clutch includes: first, rapidly engaging the clutch to a first position, and then controlling the clutch to slowly engage at a certain inclination M. For example, if the displacement of the clutch's zero torque transmission point (KP point) is K, segmented control of the clutch is implemented based on the KP point, that is, first rapidly engaging the clutch to the position K+L (L is a positive value), and then controlling the clutch to slowly engage at a certain inclination M, where L and M are calibration values, and the final values ​​are determined based on the actual vehicle performance.

[0061] Furthermore, in one embodiment, the step of controlling the clutch to disengage for a preset time before re-controlling the transmission master gearbox to perform the gear shifting action includes: controlling the clutch to disengage and determining whether the time when the command to disengage the clutch was issued has reached a set time threshold; if so, then re-controlling the transmission master gearbox to perform the gear shifting action; otherwise, continuing to wait until the time when the command to disengage the clutch was issued reaches the set time threshold. That is, in this embodiment, when determining the clutch disengagement time, the timing starts from the issuance of the command to disengage the clutch to calculate the clutch disengagement time, and the transmission actuator is re-controlled to perform the gear shifting action only after a certain time has elapsed since the command to disengage the clutch was issued.

[0062] In this embodiment, the clutch disengagement time is determined by whether the time of issuing the command to control clutch disengagement reaches a set time threshold, thereby making the clutch disengagement time calculation more accurate and the control timing more refined and comprehensive.

[0063] Furthermore, in one embodiment, before determining whether gear engagement has occurred in the transmission master gearbox, the following may be included:

[0064] Step a: When it is determined that the current vehicle is in a low-speed / stationary gear engagement condition, the clutch is disengaged and the transmission master set is disconnected. This determination can be made based on vehicle speed, gradient, and whether the target gear changes. The TCU can determine the vehicle's operating status based on vehicle speed (output shaft speed) and gradient. When the vehicle speed is below a certain value (this threshold is set according to the gradient), the vehicle is considered to be in an extremely low-speed state. If the target gear changes under this condition, it is determined that the vehicle is currently in a low-speed / stationary gear engagement. The TCU can also determine the clutch status based on the clutch displacement sensor. If the clutch is not disengaged, the TCU will continue to control the clutch actuator to disengage the clutch.

[0065] Step b: Control the speed adjustment of the main gearbox gear.

[0066] Step c: Control the main gearbox to perform the gear shifting action, and use segmented control to slowly engage the clutch. The segmented control method in this embodiment can be the same as the aforementioned segmented control method, and will not be repeated here. In this embodiment, the clutch control in step c is continuous with the clutch control in step S21.

[0067] Further, in one embodiment, before controlling the speed adjustment of the main gearbox gear, the method may include: determining whether the auxiliary gearbox needs to be activated based on the target gear and the current gear status of the vehicle; if the auxiliary gearbox needs to be activated, then controlling the auxiliary gearbox to engage the corresponding position. In this embodiment, if the auxiliary gearbox needs to be activated, the TCU controls the transmission actuator to engage the auxiliary gearbox to the corresponding position. The mechanical structure of a transmission generally consists of three parts: a front auxiliary gearbox, a main gearbox, and a rear auxiliary gearbox. Not every transmission has a rear auxiliary gearbox. The front and rear auxiliary gearboxes are collectively referred to as the auxiliary gearbox. The auxiliary gearbox does not need to activate every time the transmission shifts gears. The TCU determines whether the auxiliary gearbox needs to be activated based on the target gear and the current gear status. For example, assuming the number of forward gears in the transmission is A (A is an even number), the current gear is B, and the target gear is C, the situations regarding whether the auxiliary gearbox needs to be activated are shown in Table 1 below:

[0068] Table 1: Status of the auxiliary box's operation

[0069] B is an odd number, and C is an even number. B > A / 2, C ≤ A / 2 B is an even number, and C is an odd number. C > A / 2, B ≤ A / 2

[0070] In this embodiment, by judging the target gear and the current gear, it is possible to accurately determine whether the auxiliary gearbox needs to operate, making the control strategy more refined and reasonable.

[0071] Further, in one embodiment, controlling the speed adjustment of the transmission master gear includes: calculating the speed difference between the target gear and the current gear based on the rotational speeds of the transmission intermediate shaft and the master shaft; then determining whether the speed difference is within a set threshold range; if so, controlling the transmission master gear to perform a gear engagement action; otherwise, controlling the intermediate shaft brake or clutch to adjust the speed. In this embodiment, the TCU calculates the speed difference between the target gear and the current gear based on the rotational speeds of the transmission intermediate shaft and the master shaft obtained from the speed sensor, referred to as the "dog-tooth speed difference." If this speed difference is not within the set threshold range, the TCU needs to adjust the speed by controlling the intermediate shaft brake or clutch. If the speed difference is within the set threshold range, the TCU can control the transmission actuator to complete the gear engagement action, simultaneously controlling the clutch to begin engaging using a segmented control method. If the transmission does not engage the gears, the transmission successfully engages the target gear, indicating successful gear engagement. After gear engagement, the clutch is simultaneously disengaged.

[0072] The threshold range of the gearbox master gear shift speed difference can be adjusted based on the output shaft speed A, the output shaft speed change rate B, and the basic threshold range of the gear shift speed difference [C1, C2]. For example, under a certain working condition, when the slope output shaft speed A is -20 rpm or the output shaft speed change rate B is -50 rpm / s, if the current basic threshold range of the gear shift speed difference is [-50, 50] rpm, then the threshold range of the gearbox master gear shift speed difference is obtained by looking up the table based on the output shaft speed change rate as [-100, 100].

[0073] In this embodiment, the speed difference between the target gear and the current gear can be calculated by using the rotational speed values ​​of the intermediate shaft and the main shaft of the gearbox, and it can be determined whether the speed difference is within the set threshold range, so as to make an accurate judgment on whether speed adjustment is needed.

[0074] Furthermore, in one embodiment, the ultra-low speed gear shifting control method without synchronizer may further include: during gear shifting, real-time monitoring of the transmission output shaft speed to determine the vehicle's operating status; when it is detected that the vehicle rolls backward or the rate of decrease in output shaft speed is less than a preset value during gear shifting, the transmission's gear shifting speed difference threshold is increased. In this embodiment, to save gear shifting time while ensuring gear shifting success rate, the TCU determines the vehicle's operating status by real-time monitoring of the transmission output shaft speed. If it detects that the vehicle rolls backward (output shaft speed is negative) or the rate of decrease in output shaft speed (negative value) is less than a certain value (this rate is calculated by the decrease in output shaft speed per unit time), the TCU appropriately widens the gear shifting speed difference threshold range and exits this stage early, avoiding prolonged shifting time due to excessive speed adjustment time, which could lead to excessive power loss and a poor driving experience for the driver and passengers. Furthermore, after detecting gear misalignment, the TCU extends the threshold of the transmission master gearbox's single gear shifting time when re-engaging, ensuring a high gear shifting success rate.

[0075] For example, the single gear shift speed difference threshold of the transmission master gearbox is D. That is, during the gear shifting phase, if the transmission still fails to shift gears after the TCU controls the shift solenoid valve of the transmission actuator to work for E milliseconds, it is considered that the gear shift is misaligned. If the gear shift is misaligned and the transmission re-enters the gear shifting phase, the TCU will extend the single gear shifting threshold to E+F (F is a positive value).

[0076] See Figure 3 The diagram shown is a timing illustration of gearbox master gear shifting according to an embodiment of this application. Figure 3 The horizontal axis in the graph represents time. (See the graph.)

[0077] Stage 1: The TCU has controlled the clutch actuator to disengage the clutch and empty the main gearbox.

[0078] Phase 2: The TCU controls the transmission actuator to engage the auxiliary gearbox.

[0079] Phase 3: The TCU controls the clutch actuator to quickly engage the clutch to the KP position, while simultaneously controlling the gearbox actuator to engage gears.

[0080] Stage 4: After the clutch displacement passes the (KP+L) point (L is the offset, a positive value, obtained from calibration), the TCU's control of the clutch changes to slope M control, gradually engaging the clutch at a certain slope M. Simultaneously, the transmission master gearbox can be seen stuck in the middle position, indicating that gear engagement has occurred.

[0081] Phase 5: The TCU determines the gearbox is engaged and disconnects the main gearbox.

[0082] Phase 6: After the main gearbox is disengaged, wait for the clutch to bring up the speed of the intermediate shaft and disengage the gears.

[0083] Stage 7: The TCU detects that the intermediate shaft speed has reached the set threshold and controls the clutch actuator to disengage the clutch.

[0084] Phase 8: The TCU enters the waiting phase before shifting gears, waiting for the clutch to disengage.

[0085] Stage 9: The TCU controls the transmission actuator to perform the transmission shifting action, and the shifting is completed.

[0086] The gear shifting control technology in related technologies lacks precision in clutch control. Multiple gear engagements gradually increase the clutch engagement depth, exacerbating the aforementioned shifting shock. This application successfully solves the problem of gear shifting shock in heavy-duty commercial vehicle AMTs at low speeds / stationary states, while also considering shifting speed. Its strategy is more refined and reasonable, and it offers better compatibility with differences in the mechanical characteristics of different batches of hardware products.

[0087] The technical solution of this application optimizes and upgrades the shifting sequence under low-speed / stationary conditions. When the transmission master gearbox engages a gear, it ensures that the clutch disengages to a certain extent, avoiding shifting shock. At the same time, the connection between each timing sequence is as compact as possible to balance shifting time. Furthermore, the control method for clutch segment control is more refined, which can effectively avoid wasting shifting time due to excessive clutch engagement caused by insufficient clutch control precision or mechanical differences. In addition, the TCU in this technical solution provides more refined and comprehensive control timing for each actuator, which can effectively accommodate the differences in mechanical characteristics of different batches of hardware, making it more universal.

[0088] Secondly, embodiments of this application also provide a gear shifting control device for extremely low vehicle speeds without a synchronizer.

[0089] In one embodiment, the ultra-low speed gear shifting control device without synchronizer includes: an automatic transmission control unit (TCU) for determining whether gear engagement occurs in the transmission master gearbox; the TCU is also used to control the transmission master gearbox to shift to neutral when gear engagement occurs, and to control the clutch to disengage for a preset time after the rotational speed of the transmission intermediate shaft reaches a set threshold range before re-controlling the transmission master gearbox to perform the gear shifting action.

[0090] Furthermore, in one embodiment, the automatic transmission control unit is used to control the transmission master gearbox to shift to neutral and to control the clutch to engage slowly in a segmented control manner so as to drive the intermediate shaft to rotate slowly; and to determine whether the speed of the intermediate shaft has reached a set threshold range; if so, the clutch is disengaged for a preset time and then the transmission master gearbox is re-controlled to perform the gear engagement action; otherwise, the system continues to wait for the clutch to bring the speed of the intermediate shaft to the threshold range.

[0091] Furthermore, in one embodiment, the automatic transmission control unit is also used to first quickly engage the clutch to a first position, and then control the clutch to engage slowly at a certain inclination M.

[0092] Furthermore, in one embodiment, the automatic transmission control unit is also used to control clutch disengagement and determine whether the time of issuing the command to control clutch disengagement has reached a set time threshold; if so, the transmission master gearbox is re-controlled to perform the gear shifting action; otherwise, it continues to wait until the time of issuing the command to control clutch disengagement reaches the set time threshold.

[0093] Furthermore, in one embodiment, the automatic transmission control unit is also used to control the clutch to disengage and disengage the transmission master gearbox when it is determined that the current vehicle is in a low-speed / stationary gear-shifting condition; control the transmission master gearbox to adjust the speed; and control the transmission master gearbox to perform a gear-shifting action, and use a segmented control method to control the clutch to engage slowly.

[0094] Furthermore, in one embodiment, the automatic transmission control unit is also used to determine whether the transmission auxiliary gearbox needs to be activated based on the target gear and the current gear status of the vehicle; if the transmission auxiliary gearbox needs to be activated, the control unit controls the transmission auxiliary gearbox to be engaged in the corresponding position.

[0095] Furthermore, in one embodiment, the automatic transmission control unit is used to calculate the speed difference between the target gear and the current gear based on the rotational speed values ​​of the intermediate shaft and the main shaft of the transmission; determine whether the speed difference is within a set threshold range; if so, control the main shaft of the transmission to perform a gear engagement action; otherwise, control the intermediate shaft brake or clutch to adjust the speed.

[0096] Furthermore, in one embodiment, the automatic transmission control unit is also used to monitor the transmission output shaft speed in real time to determine the vehicle's operating status. When it is detected that the vehicle rolls backward or the rate of decrease in the output shaft speed is less than a preset value during transmission shifting, the transmission shifting speed difference threshold is increased.

[0097] The functions of each module in the aforementioned ultra-low speed gear shifting control device without synchronizer correspond to the steps in the aforementioned ultra-low speed gear shifting control method embodiment, and their functions and implementation processes will not be described in detail here.

[0098] Thirdly, embodiments of this application provide an automobile that includes the aforementioned extremely low speed gear shifting control device without synchronizer.

[0099] It should be noted that the sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0100] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above, and includes several instructions to cause a terminal device to execute the methods described in the various embodiments of this application.

[0101] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A method for controlling gear shifting without a synchronizer at extremely low vehicle speeds, characterized in that, The method for controlling gear shifting without a synchronizer at extremely low vehicle speeds includes: Determine if gear misalignment occurs during gear shifting in the main gearbox; If so, the transmission master gearbox is controlled to shift to neutral, and when the speed of the transmission intermediate shaft reaches the set threshold range, the clutch is controlled to disengage for a preset time before the transmission master gearbox is re-controlled to perform the gear engagement action. The control of the transmission master gearbox to disengage into neutral, and when the rotational speed of the transmission intermediate shaft reaches a set threshold range, controlling the clutch to disengage for a preset time before re-controlling the transmission master gearbox to perform a gear engagement action, includes: The main gearbox is shifted to neutral, and the clutch is engaged slowly using a segmented control method to drive the intermediate shaft to rotate slowly. Determine whether the rotational speed of the intermediate shaft has reached the set threshold range; If so, the clutch will disengage for a preset time before the transmission master gearbox is re-controlled to perform the gear shifting action; Otherwise, continue to wait for the clutch to bring the intermediate shaft speed to the threshold range; The method of controlling the clutch to engage slowly by segmented control includes: first, quickly engaging the clutch to the first position, and then controlling the clutch to engage slowly at a certain slope M. The method for controlling gear shifting without a synchronizer at extremely low vehicle speeds also includes: The vehicle's operating status is determined by real-time monitoring of the transmission output shaft speed. When the vehicle rolls backward or the rate of decrease in output shaft speed is less than a preset value during transmission shifting, the transmission shifting speed difference threshold is increased.

2. The method for controlling gear shifting at extremely low vehicle speeds without a synchronizer as described in claim 1, characterized in that, The step of controlling the clutch to disengage for a preset time before re-controlling the transmission master gearbox to perform the gear shifting action includes: Control the clutch to disengage and determine whether the time of issuing the command to control the clutch to disengage has reached the set time threshold; If so, the master gearbox will be re-controlled to perform the gear shifting action; otherwise, continue to wait until the time it takes for the command to disengage the clutch reaches the set time threshold.

3. The method for controlling gear shifting at extremely low vehicle speeds without a synchronizer as described in claim 1, characterized in that, Before determining whether gear misalignment has occurred during gear shifting in the main gearbox, the method further includes: When it is determined that the vehicle is in a low-speed / stationary gear-shifting condition, the clutch is disengaged and the transmission master set is disconnected. Control the speed regulation of the main gearbox gear; The transmission master gearbox is controlled to perform gear shifting actions, and the clutch is slowly engaged using a segmented control method.

4. The method for controlling gear shifting at extremely low vehicle speeds without a synchronizer as described in claim 3, characterized in that, Before controlling the speed adjustment of the main gearbox gear, the following is also included: Determine whether the auxiliary gearbox needs to be activated based on the target gear and the vehicle's current gear status; If the auxiliary gearbox needs to be activated, control the auxiliary gearbox to engage the appropriate position.

5. The method for controlling gear shifting at extremely low vehicle speeds without a synchronizer as described in claim 3, characterized in that, The control of the main gearbox speed regulation includes: Calculate the speed difference between the target gear and the current gear based on the rotational speeds of the intermediate shaft and main shaft of the gearbox; Determine whether the speed difference is within the set threshold range; If so, the main gearbox is controlled to engage the gear; otherwise, the intermediate shaft brake or clutch is controlled to adjust the speed.

6. A gear shifting control device for extremely low vehicle speeds without a synchronizer, characterized in that, The ultra-low speed gear shifting control device without synchronizer includes: The automatic transmission control unit is used to determine whether gear misalignment has occurred when the transmission master gear is engaged. The automatic transmission control unit is also used to control the transmission master gearbox to disengage into neutral when gear engagement occurs, and to control the clutch to disengage for a preset time after the rotational speed of the transmission intermediate shaft reaches a set threshold range before re-controlling the transmission master gearbox to perform the gear engagement action. The control of the transmission master gearbox to disengage into neutral, and when the rotational speed of the transmission intermediate shaft reaches a set threshold range, controlling the clutch to disengage for a preset time before re-controlling the transmission master gearbox to perform a gear engagement action, includes: The main gearbox is shifted to neutral, and the clutch is engaged slowly using a segmented control method to drive the intermediate shaft to rotate slowly. Determine whether the rotational speed of the intermediate shaft has reached the set threshold range; If so, the clutch will disengage for a preset time before the transmission master gearbox is re-controlled to perform the gear shifting action; Otherwise, continue to wait for the clutch to bring the intermediate shaft speed to the threshold range; The method of controlling the clutch to engage slowly by segmented control includes: first, quickly engaging the clutch to the first position, and then controlling the clutch to engage slowly at a certain slope M. The vehicle's operating status is determined by real-time monitoring of the transmission output shaft speed. When the vehicle rolls backward or the rate of decrease in output shaft speed is less than a preset value during transmission shifting, the transmission shifting speed difference threshold is increased.

7. A car, characterized in that, It includes the ultra-low speed gear shifting control device without synchronizer as described in claim 6.

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