Downshift control method, apparatus, and device, and storage medium

Abstract

A downshift control method, apparatus, and device, and a storage medium, relating to the technical field of automobiles. The method comprises: step S10, upon detecting that a vehicle is in a direct drive mode and emergency braking is being performed, acquiring a current driving gear of the vehicle; step S20, upon detecting that the driving gear is a high-speed gear, acquiring a current real-time vehicle speed and real-time acceleration of the vehicle; step S30, when the real-time vehicle speed is greater than a preset speed threshold and the real-time acceleration is less than a preset acceleration threshold, predicting a target driving gear required by the vehicle; and step S40, on the basis of the target driving gear, controlling the vehicle to downshift in advance. The present method allows the direct coupling between the engine and the wheel ends to be disengaged in advance, so that the engine rotational speed does not drop excessively while following the wheel-end rotational speed corresponding to the real-time vehicle speed, thereby avoiding engine stall.

Description

Downshift control method, device, equipment and storage medium

[0001] This application claims priority to Chinese patent application No. 202410951401.9, filed on July 16, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of automotive technology, and in particular to a downshift control method, device, equipment, and storage medium. Background Technology

[0003] As the market share of new energy vehicles gradually increases, the trend of vehicle electrification is becoming increasingly apparent. As a crucial component of new energy vehicles, transmissions are also constantly being upgraded to adapt to the electrification requirements of the entire vehicle. Currently, new energy vehicles equipped with hybrid transmissions have been developed. These hybrid transmissions can achieve multiple modes, including series mode, two electronically controlled variable transmission (ECVT) modes, four direct drive modes, and pure electric (EV) mode, adapting to various driving scenarios. However, these hybrid transmissions only control two synchronizers for shifting via a single shifting mechanism, resulting in only sequential shifting. This means the vehicle is in direct drive mode. In emergency braking scenarios, this type of transmission has a slow downshifting speed and cannot quickly decouple the engine from the wheels, causing the engine speed to drop rapidly along with the vehicle's wheel speed, leading to engine stalling. Technical issues

[0004] The main objective of this application is to provide a downshift control method, device, equipment, and storage medium, which aims to solve the technical problem of how to enable a vehicle with a hybrid transmission that only supports sequential shifting to quickly downshift during emergency braking in direct drive mode, so as to prevent engine stalling due to slow downshifting speed and excessively low engine speed. Technical solutions

[0005] To achieve the above objectives, this application provides a downshift control method applied to a hybrid vehicle with a transmission capable only of sequential gear shifting. The downshift control method includes:

[0006] When the vehicle is detected to be in direct drive mode and emergency braking is performed, the current driving gear of the vehicle is obtained;

[0007] When the driving gear is detected to be a high gear, the real-time speed and real-time acceleration of the vehicle are collected.

[0008] When the real-time vehicle speed is greater than a preset speed threshold and the real-time acceleration is less than a preset acceleration threshold, the target driving gear required by the vehicle is predicted.

[0009] Based on the target driving gear, the vehicle is controlled to downshift in advance.

[0010] In one embodiment, after controlling the vehicle to downshift in advance based on the target driving gear, the method further includes:

[0011] When controlling the vehicle to downshift, control the vehicle to perform a disengagement operation;

[0012] When the vehicle completes the disengagement operation, the vehicle is controlled to shift to the target driving gear to complete the downshift.

[0013] In one embodiment, after controlling the vehicle to perform a disengagement operation when downshifting, the method further includes:

[0014] When the vehicle begins to perform the disengagement operation, the torque at both ends of the synchronizer is adjusted by the generator, and the real-time torque difference corresponding to the torque at both ends of the synchronizer is obtained, and the current engine speed is obtained.

[0015] When the engine speed is lower than the minimum engine speed corresponding to the direct drive mode, if the real-time torque difference is less than the first preset torque difference, the shift motor is controlled to disengage at the first preset speed to complete the disengagement operation in advance.

[0016] In one embodiment, after adjusting the torque at both ends of the synchronizer via the generator when the vehicle begins to perform the disengagement operation, simultaneously obtaining the real-time torque difference corresponding to the torque at both ends of the synchronizer, and obtaining the current engine speed, the method further includes:

[0017] When the engine speed is not lower than the minimum engine speed, if the real-time torque difference is less than the second preset torque difference, the shift motor is controlled to disengage at the second preset speed to complete the disengagement operation.

[0018] Wherein, the second preset torque difference is lower than the first preset torque difference, and the second preset speed is lower than the first preset speed.

[0019] In one embodiment, when controlling the vehicle to downshift, after controlling the vehicle to perform a disengagement operation, the method further includes:

[0020] When the vehicle completes the disengagement operation, the vehicle is controlled to enter ECVT mode to improve the user's comfort during the vehicle's gear shifting process.

[0021] In one embodiment, after detecting that the driving gear is a high gear and collecting the vehicle's current real-time speed and real-time acceleration, the method further includes:

[0022] When the real-time vehicle speed is less than the preset speed threshold, the target driving gear is obtained;

[0023] Based on the target driving gear, the vehicle is controlled to downshift.

[0024] In one embodiment, before predicting the target gear required by the vehicle when the real-time vehicle speed is greater than a preset speed threshold and the real-time acceleration is less than a preset acceleration threshold, the method further includes:

[0025] Based on the vehicle's driving gear and a pre-set vehicle downshift condition table, the preset speed threshold and the preset acceleration threshold are obtained to determine whether the current driving gear needs to be downshifted in advance.

[0026] Furthermore, to achieve the above objectives, this application also provides a downshift control device, the downshift control device comprising:

[0027] The gear position acquisition module is used to acquire the current driving gear of the vehicle when it is detected that the vehicle is in direct drive mode and is performing emergency braking.

[0028] The speed acquisition module is used to collect the real-time speed and real-time acceleration of the vehicle when the driving gear is detected to be a high gear.

[0029] The shift prediction module is used to predict the target driving gear required by the vehicle when the real-time vehicle speed is greater than a preset speed threshold and the real-time acceleration is less than a preset acceleration threshold.

[0030] The shift control module is used to control the vehicle to downshift in advance based on the target driving gear.

[0031] In addition, to achieve the above objectives, this application also provides a downshift control device, the downshift control device comprising: a memory, a processor, and a downshift control program stored in the memory and executable on the processor, the downshift control program being configured to implement the steps of the downshift control method as described above.

[0032] In addition, to achieve the above objectives, this application also provides a storage medium, which is a computer-readable storage medium, and stores a downshift control program thereon. When the downshift control program is executed by a processor, it implements the steps of the downshift control method described above. Beneficial effects

[0033] This application provides a downshift control method, apparatus, device, and storage medium. The downshift control method includes the following steps: when the vehicle is detected to be in direct drive mode and undergoing emergency braking, acquiring the current driving gear of the vehicle; when the driving gear is detected to be a high gear, collecting the current real-time vehicle speed and real-time acceleration of the vehicle; when the real-time vehicle speed is greater than a preset speed threshold and the real-time acceleration is less than a preset acceleration threshold, predicting the target driving gear required by the vehicle; and controlling the vehicle to downshift in advance based on the target driving gear. When the vehicle is detected to be driving in a high-efficiency direct-drive mode and an emergency braking is required, if the current driving gear is a high-speed gear, the real-time vehicle speed and the real-time acceleration generated by braking are obtained. If the current real-time vehicle speed is still higher than a preset speed threshold, while the real-time acceleration generated by braking is lower than a preset acceleration threshold, it can be determined that the current real-time vehicle speed is about to drop to the speed corresponding to a lower gear. At this time, the target driving gear that the vehicle needs to downshift to can be predicted by the values ​​of real-time vehicle speed and real-time acceleration, and the downshift operation is performed in advance. This decouples the engine from the wheel end in advance, thereby preventing the engine speed from dropping too low to match the wheel end speed corresponding to the real-time vehicle speed, which could lead to engine stalling. Attached Figure Description

[0034] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0035] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 is a flowchart of the downshift control method provided in Embodiment 1 of this application;

[0037] Figure 2 is a flowchart of the downshift control method provided in Embodiment 2 of this application;

[0038] Figure 3 is a flowchart of the downshift control method provided in Embodiment 3 of this application;

[0039] Figure 4 is a schematic diagram of the module structure of the downshift control device according to an embodiment of this application;

[0040] Figure 5 is a schematic diagram of the downshift control device according to an embodiment of this application.

[0041] The purpose, features, and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Embodiments of the present invention

[0042] It should be understood that the specific embodiments described herein are merely illustrative of the technical solutions of this application and are not intended to limit this application.

[0043] To better understand the technical solution of this application, a detailed description will be provided below in conjunction with the accompanying drawings and specific implementation methods.

[0044] The main solution of this application is as follows: In scenarios where the vehicle is driving in direct drive mode and requires emergency braking, if the current driving gear of the vehicle is a high-speed gear, the real-time vehicle speed and real-time acceleration are obtained. If the real-time vehicle speed has not yet decreased to a preset speed threshold and the real-time acceleration has already fallen below a preset acceleration threshold, the system predicts the target driving gear that the vehicle needs to downshift to. Furthermore, the system controls the vehicle to downshift in advance before the real-time vehicle speed drops below the preset speed threshold, decoupling the engine speed from the real-time vehicle speed and preventing the engine from stalling due to excessively low engine speed.

[0045] Currently, with the promotion of automotive electrification, hybrid transmissions have been developed that can switch freely between series mode, multiple ECVT modes, direct drive mode, and pure electric mode. These vehicles have no clutch; they achieve the switching between these modes solely through a single shifting mechanism controlling two synchronizers. However, they only support sequential shifting, resulting in slow shifting speeds. During high-speed driving, these vehicles typically operate in the more efficient direct drive mode. If sudden emergency braking is required, the vehicle speed drops rapidly. Due to the slow shifting speed, the engine may slow down before the shift is complete, potentially causing the engine speed to drop below the minimum operating speed, leading to engine stalling. Sudden engine stalling at high speeds poses a serious safety hazard. Therefore, enabling vehicles with hybrid transmissions that only support sequential shifting to quickly downshift during emergency braking in direct drive mode to prevent engine stalling due to slow downshifting and excessively low engine speed is a pressing issue that needs to be addressed.

[0046] When this application detects that the vehicle is currently driving in a direct-drive mode with high transmission efficiency and needs to perform emergency braking, if the current driving gear is a high-speed gear, it acquires the vehicle's current real-time speed and the real-time acceleration generated by braking. If the current real-time speed is still higher than a preset speed threshold, and the real-time acceleration generated by braking is lower than a preset acceleration threshold, it can be determined that the vehicle's current real-time speed is about to urgently drop to the driving speed corresponding to a lower gear. At this time, the target driving gear that the vehicle needs to drop to can be predicted by the values ​​of real-time speed and real-time acceleration, and the downshift operation can be performed in advance. This will decouple the engine from the wheel end in advance, thereby preventing the engine speed from dropping too low to match the wheel end speed corresponding to the real-time vehicle speed, which could lead to engine stalling.

[0047] It should be noted that the executing entity in this embodiment can be a downshift control device, or a downshift control device with data processing, network communication, and program execution functions, etc. This embodiment does not specifically limit it. The following uses a downshift control device as the executing entity to describe this embodiment and the following embodiments.

[0048] Based on this, this application proposes a downshift control method according to a first embodiment. Referring to Figure 1, the downshift control method includes steps S10-S40:

[0049] Step S10: When it is detected that the vehicle is in direct drive mode and performs emergency braking, the current driving gear of the vehicle is obtained.

[0050] It should be noted that the downshift control method proposed in this embodiment can be mainly applied to hybrid vehicles with hybrid transmissions. These transmissions can operate in series mode, multiple ECVT modes, multiple direct drive modes, and EV mode where the P1 generator and ICE engine are decoupled. They can also freely switch between the aforementioned operating modes to adapt to various driving scenarios. Specifically, it can be applied to, for example, the multi-mode hybrid transmission solution proposed in patent CN112224007B, a multi-mode hybrid dedicated transmission.

[0051] This patent proposes using a single shifting mechanism to control two synchronizers for gear shifting, enabling switching between the various operating modes mentioned above. However, this also limits vehicles using this transmission to sequential gear shifting, resulting in slow shifting speeds. In situations requiring high-speed driving, such as on highways, vehicles using this transmission typically switch to more efficient direct-drive gears. If emergency braking is needed, the vehicle speed drops rapidly due to braking, causing a corresponding drop in wheel speed. Simultaneously, due to the slow shifting speed, the engine cannot quickly decouple from the wheels, causing the engine speed to drop rapidly as well. In this situation, the engine speed may drop below the minimum operating speed, potentially leading to engine stalling. Given the high-speed driving conditions, engine stalling makes it difficult for the driver to control the vehicle, posing a safety hazard.

[0052] It is easy to understand that in this embodiment, when the hybrid vehicle is driving in a direct drive mode with high transmission efficiency, if an emergency braking is required due to a sudden danger ahead, the current driving gear of the vehicle can be obtained first to determine whether the current emergency braking requirement is urgent.

[0053] It should be understood that a vehicle's gears are generally divided into P (Park), R (Reverse), Neutral, and gears 1 through 5, or other gear settings. Gears 1 through 5 correspond to different speed ranges from low to high. Gears 3, 4, and 5 can be considered high-speed gears, while gears 1 and 2 can be considered low-speed gears. In emergency braking scenarios, if the vehicle is detected to be in a high gear, the braking demand is high to ensure the safety of the driver and passengers, and the vehicle speed will drop rapidly. In this case, it can be assumed that the transmission's shifting speed cannot meet the downshifting speed required for the speed reduction, which may result in excessively low engine speed. Conversely, if the vehicle is detected to be in a low gear, the speed will decrease more slowly. In this case, it can be assumed that the transmission's shifting speed can meet the downshifting speed required for the speed reduction, and only normal downshifting is needed, without excessively low engine speed.

[0054] It is worth noting that in this embodiment, the need for emergency braking can be determined by collecting the brake pedal depth signal. If the vehicle is equipped with other sensing devices such as lidar, millimeter-wave radar, or cameras that can automatically detect obstacles ahead, or if the system includes multiple such sensing devices, the signals transmitted by these sensors can also be used to automatically determine the need for emergency braking and automatically perform emergency braking.

[0055] Step S20: When the driving gear is detected to be a high gear, the real-time speed and real-time acceleration of the vehicle are collected.

[0056] It is easy to understand that in this embodiment, if the current driving gear of the vehicle is detected to be a high gear such as 3rd, 4th or 5th gear in the scenario of emergency braking, the real-time speed and real-time acceleration of the vehicle under emergency braking are obtained.

[0057] It is worth noting that in this embodiment, both the real-time vehicle speed and the real-time acceleration are vector values. The real-time vehicle speed should be a positive value and be in a state of rapid decline. During the rapid decline, the real-time vehicle speed may not change linearly. The real-time acceleration should be a negative value. The real-time acceleration decreases rapidly when the real-time vehicle speed is high, and increases slowly as the real-time vehicle speed gradually decreases, gradually approaching 0.

[0058] Step S30: When the real-time vehicle speed is greater than a preset speed threshold and the real-time acceleration is less than a preset acceleration threshold, predict the target driving gear required by the vehicle.

[0059] It should be noted that the preset speed threshold is a pre-set calibrated value used to determine whether the current real-time vehicle speed is lower than the minimum speed corresponding to the current gear. If the real-time vehicle speed is lower than the preset speed threshold, it indicates that a downshift is urgently needed. To avoid situations where the downshifting speed of the entire vehicle cannot keep up with the real-time speed decrease, a preset acceleration threshold is also introduced as an auxiliary judgment condition. The preset acceleration threshold is a pre-set calibrated value used to determine whether continuing to decelerate at the current real-time acceleration will immediately cause the real-time vehicle speed to drop below the preset speed threshold. If the real-time acceleration is lower than the preset acceleration threshold, it indicates that the current real-time vehicle speed will still decrease sharply and is highly likely to immediately drop below the preset speed threshold corresponding to the current gear. This can predict in advance that a downshift is urgently needed. This auxiliary judgment mechanism is faster than the judgment mechanism that only judges based on real-time vehicle speed and has a predictive function.

[0060] It is easy to understand that if the current real-time vehicle speed is greater than the preset speed threshold and the real-time acceleration is less than the preset acceleration threshold, it means that the real-time vehicle speed is likely to drop below the preset speed threshold in a very short time. At this time, it can be predicted that the vehicle needs to downshift to the target driving gear in advance.

[0061] Step S40: Based on the target driving gear, control the vehicle to downshift in advance.

[0062] It is easy to understand that in this embodiment, if the target driving gear is obtained in advance, downshifting can be performed before the real-time vehicle speed drops below a preset speed threshold. This decouples the engine from the wheels, mitigating the impact of wheel speed (real-time vehicle speed) on engine speed. By predicting changes in real-time vehicle speed and downshifting in advance, the slow shifting speed of the transmission is compensated for, ensuring that the engine speed does not drop below the minimum engine speed required for engine operation, thus preventing engine stalling.

[0063] This application provides a downshift control method, the steps of which include: when the vehicle is detected to be in direct drive mode and undergoing emergency braking, obtaining the current driving gear of the vehicle; when the driving gear is detected to be a high gear, collecting the current real-time vehicle speed and real-time acceleration of the vehicle; when the real-time vehicle speed is greater than a preset speed threshold and the real-time acceleration is less than a preset acceleration threshold, predicting the target driving gear required by the vehicle; and based on the target driving gear, controlling the vehicle to downshift in advance. When the vehicle is detected to be driving in a high-efficiency direct-drive mode and an emergency braking is required, if the current driving gear is a high-speed gear, the real-time vehicle speed and the real-time acceleration generated by braking are obtained. If the current real-time vehicle speed is still higher than a preset speed threshold, while the real-time acceleration generated by braking is lower than a preset acceleration threshold, it can be determined that the current real-time vehicle speed is about to drop to the speed corresponding to a lower gear. At this time, the target driving gear that the vehicle needs to downshift to can be predicted by the values ​​of real-time vehicle speed and real-time acceleration, and the downshift operation is performed in advance. This decouples the engine from the wheel end in advance, thereby preventing the engine speed from dropping too low to match the wheel end speed corresponding to the real-time vehicle speed, which could lead to engine stalling.

[0064] Based on the first embodiment of this application, in the second embodiment of this application, the content that is the same as or similar to that in the first embodiment described above can be referred to the above description and will not be repeated hereafter. Based on this, please refer to Figure 2. After the step of controlling the vehicle to downshift in advance based on the target driving gear, the method further includes:

[0065] Step S51: When controlling the vehicle to downshift, control the vehicle to perform a disengagement operation.

[0066] It should be noted that in this embodiment, for example, the transmission in the multi-mode hybrid dedicated transmission scheme proposed in the aforementioned patent, if its low-speed driving gears include gears 1 and 2, and its high-speed driving gears include gears 3 and 4, and it can realize ECVT mode and EV mode (decoupling the P1 generator and ICE engine) through a planetary disk structure, then in direct drive mode, its shift positions are series-1 gear-ECVT1-2 gear-ECVT2-EV-ECVT3-3 gear-ECVT4-4 gear, shifting sequentially from left to right or from right to left. During the shifting process, to reduce the impact force generated by switching between different gears and to reduce wear on the engine and transmission, a disengagement operation is performed first at each shift stage to return the gear to neutral.

[0067] Step S52: When the vehicle completes the disengagement operation, control the vehicle to shift to the target driving gear to complete the downshift.

[0068] It's easy to understand that after the entire gear disengagement operation is completed, the vehicle's driving gear can be shifted to a lower target driving gear. At this point, the entire gear shifting process can be considered complete. At this point, the entire downshifting process is complete. Because the gear ratio of the lower gear is higher than that of the higher gear, the engine speed will increase accordingly to match the real-time vehicle speed, resulting in higher combustion efficiency and preventing the engine from stalling.

[0069] Furthermore, in this embodiment, after the step of controlling the vehicle to perform the disengagement operation when controlling the vehicle to downshift, the method further includes:

[0070] Step S511: When the vehicle starts to perform the disengagement operation, the torque at both ends of the synchronizer is adjusted by the generator, and the real-time torque difference corresponding to the torque at both ends of the synchronizer is obtained, and the current engine speed is obtained.

[0071] It should be noted that in this embodiment, during the disengagement phase, the torque at both ends of the synchronizer can be adjusted by the P1 generator to gradually reduce the torque at both ends of the synchronizer, thereby reducing the impact of the shifting process, reducing wear between components, improving shifting efficiency, and enhancing the user's driving comfort.

[0072] It is easy to understand that, in this embodiment, in order to make the shifting process smoother, the real-time torque difference between the torques at both ends of the synchronizer and the current engine speed can also be obtained in real time through various vehicle sensors on the vehicle, so as to determine whether the shift can be disengaged with minimal wear.

[0073] Step S512: When the engine speed is lower than the minimum engine speed corresponding to the direct drive mode, if the real-time torque difference is less than the first preset torque difference, the shift motor is controlled to disengage at the first preset speed to complete the disengagement operation in advance.

[0074] It is easy to understand that the first preset torque difference value refers to the calibrated value corresponding to a relatively large but still acceptable wear level that can be achieved when disengaging the gear. If the real-time torque difference value is equal to the first preset torque difference value, disengaging the gear is allowed, but this will cause significant wear. In this embodiment, if the currently acquired engine speed is lower than the minimum engine speed required to ensure normal engine operation in direct drive mode, it indicates that disengaging the gear should be performed as soon as possible to increase the engine speed and prevent engine stalling. In this case, if the currently acquired real-time torque difference value is detected to be lower than the first preset torque difference value, it indicates that the worst-case disengagement condition has been met. At this time, the shift motor can be controlled to shift to neutral at a faster first preset speed to advance the subsequent shifting process, i.e., to complete the disengagement operation as quickly as possible.

[0075] Furthermore, in this embodiment, after the steps of adjusting the torque at both ends of the synchronizer by the generator when the vehicle begins to perform the disengagement operation, simultaneously obtaining the real-time torque difference corresponding to the torque at both ends of the synchronizer, and obtaining the current engine speed, the method further includes:

[0076] Step S513: When the engine speed is not lower than the minimum engine speed, if the real-time torque difference is less than the second preset torque difference, the shift motor is controlled to disengage at the second preset speed to complete the disengagement operation.

[0077] Wherein, the second preset torque difference is lower than the first preset torque difference, and the second preset speed is lower than the first preset speed.

[0078] It should be noted that the second preset torque difference is smaller than the first preset torque difference. If the current real-time torque difference of the synchronizer is lower than the preset torque difference, the disengagement process can be performed more smoothly with less wear. The corresponding second preset speed is lower than the first preset speed, resulting in less wear on the shift motor during shifting. In this embodiment, if the engine speed does not fall below the minimum engine speed, it indicates that the engine will not stall due to low speed in a short period, and disengagement can be performed at normal speed. In this case, if the currently acquired real-time torque difference is less than the second preset torque difference, it means that the condition for normal disengagement with minimal wear has been met. At this time, the shift motor can be controlled to shift the current driving gear to neutral at a slower second preset speed, thereby smoothly and easily completing the disengagement operation.

[0079] Furthermore, in this embodiment, after the step of controlling the vehicle to perform the disengagement operation when controlling the vehicle to downshift, the method further includes:

[0080] Step S53: When the vehicle completes the disengagement operation, control the vehicle to enter ECVT mode to improve the user's comfort during the vehicle's gear shifting process.

[0081] It is easy to understand that in this embodiment, whether the disengagement operation is completed normally or in advance, the vehicle will enter ECVT mode after the disengagement operation is completed. In this mode, although the engine and the wheel end are still coupled, they are not directly coupled. The engine speed can be adjusted by the torque control of the P1 generator, thereby avoiding the phenomenon of engine stalling due to low engine speed.

[0082] It is worth noting that in this embodiment, the target speed and actual speed of the engine can also be obtained, and the integral, ratio and differential values ​​of the speed difference between the target speed and the actual speed can be obtained respectively. The torque of the P1 generator can be controlled by PID using the integral, ratio and differential values ​​of the speed difference, so as to ensure that the engine speed can be stably maintained within a certain range and increase the stability of the vehicle during downshifting.

[0083] Based on the first and / or second embodiments of this application, in the third embodiment of this application, the content that is the same as or similar to the first and second embodiments described above can be referred to the above description and will not be repeated hereafter. Based on this, please refer to Figure 3. After the step of collecting the current real-time vehicle speed and real-time acceleration when the driving gear is detected to be a high-speed gear, the method further includes:

[0084] Step S30': When the real-time vehicle speed is less than the preset speed threshold, obtain the target driving gear;

[0085] It should be noted that in this embodiment, if the real-time vehicle speed has decreased to below a preset speed threshold, downshifting can proceed normally, completing the emergency braking process with minimal brake wear. Because the current real-time vehicle speed is relatively low, the target gear to be downshifted can be accurately determined at a relatively slow, normal speed.

[0086] Step S40': Based on the target driving gear, control the vehicle to downshift.

[0087] It is easy to understand that in this embodiment, if the target driving gear has been obtained, downshifting can still be performed even if the real-time vehicle speed has not dropped below the preset speed threshold. This decouples the engine from the wheel end at normal speed, reduces the impact of the wheel end speed (real-time vehicle speed) on the engine speed, and ensures that the engine will not stall.

[0088] Furthermore, in this embodiment, before the step of predicting the target driving gear required by the vehicle when the real-time vehicle speed is greater than a preset speed threshold and the real-time acceleration is less than a preset acceleration threshold, the method further includes:

[0089] Step S301: Based on the vehicle's driving gear and a pre-set vehicle downshift condition table, obtain the preset speed threshold and the preset acceleration threshold corresponding to determining whether the current driving gear needs to be downshifted in advance.

[0090] It should be noted that in this embodiment, a vehicle downshift condition table is preset. Within this table, each driving gear has a corresponding preset speed threshold and preset acceleration threshold. When the current driving gear of the vehicle is obtained, the preset speed threshold and preset acceleration threshold corresponding to that gear can be retrieved by looking up the table. For example, if the current gear is 3, the preset speed threshold can be 60 km / h, and the preset acceleration threshold can be -16 m / s; if the current gear is 4, the preset speed threshold can be 90 km / h, and the preset acceleration threshold can be -25 m / s.

[0091] It is worth noting that in this embodiment, the preset speed threshold is related to the current driving gear; the higher the current driving gear, the higher the preset speed threshold. The preset acceleration threshold is related to the current driving gear, real-time vehicle speed, and engine speed. When the driving gear and real-time vehicle speed remain unchanged, the higher the engine speed, the lower the preset acceleration threshold.

[0092] This application embodiment also provides a downshift control device, as shown in Figure 4, the downshift control device includes:

[0093] The gear position acquisition module 10 is used to acquire the current driving gear of the vehicle when it is detected that the vehicle is in direct drive mode and is performing emergency braking.

[0094] The speed acquisition module 20 is used to collect the current real-time speed and real-time acceleration of the vehicle when the driving gear is detected to be a high gear.

[0095] The shift prediction module 30 is used to predict the target driving gear required by the vehicle when the real-time vehicle speed is greater than a preset speed threshold and the real-time acceleration is less than a preset acceleration threshold.

[0096] The shift control module 40 is used to control the vehicle to downshift in advance based on the target driving gear.

[0097] The downshift control device provided in this application, employing the downshift control method described in the above embodiments, solves the technical problem of how to enable a vehicle with a hybrid transmission that only supports sequential shifting to quickly downshift during emergency braking in direct drive mode, thus preventing engine stalling due to slow downshifting speed and excessively low engine speed. Compared with related technologies, the beneficial effects of the downshift control device provided in this application are the same as those of the downshift control method provided in the above embodiments, and other technical features in the downshift control device are the same as those disclosed in the methods of the above embodiments, and will not be repeated here.

[0098] This application provides a downshift control device, which includes: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to perform the downshift control method in the above embodiment 1.

[0099] Referring to Figure 5 below, a schematic diagram of a downshift control device suitable for implementing embodiments of this application is shown. The downshift control device in the embodiments of this application may include, but is not limited to, fixed terminals such as vehicle-mounted terminals. The downshift control device shown in Figure 5 is merely an example and should not impose any limitations on the functionality and scope of use of the embodiments of this application.

[0100] As shown in Figure 5, the downshift control device may include a processing unit 1001 (e.g., a central processing unit, a graphics processing unit, etc.), which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) 1002 or a program loaded from a storage device 1003 into a random access memory (RAM) 1004. The RAM 1004 also stores various programs and data required for the operation of the downshift control device. The processing unit 1001, ROM 1002, and RAM 1004 are interconnected via a bus 1005. An input / output (I / O) interface 1006 is also connected to the bus. Typically, the following systems can be connected to the I / O interface 1006: input devices 1007 including, for example, a touchscreen, touchpad, keyboard, mouse, image sensor, microphone, accelerometer, gyroscope, etc.; output devices 1008 including, for example, a liquid crystal display (LCD), speaker, vibrator, etc.; storage devices 1003 including, for example, magnetic tape, hard disk, etc.; and communication devices 1009. The communication device 1009 allows the downshift control device to communicate wirelessly or wiredly with other devices to exchange data. Although downshift control devices with various systems are shown in the figures, it should be understood that implementation or possession of all the systems shown is not required. More or fewer systems may be implemented alternatively.

[0101] Specifically, according to the embodiments disclosed in this application, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, embodiments disclosed in this application include a computer program product comprising a computer program carried on a computer-readable medium, the computer program containing program code for performing the methods shown in the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network via a communication device, or installed from storage device 1003, or installed from ROM 1002. When the computer program is executed by processing device 1001, it performs the functions defined in the methods of the embodiments disclosed in this application.

[0102] The downshift control device provided in this application, employing the downshift control method described in the above embodiments, solves the technical problem of how to enable a vehicle with a hybrid transmission that only supports sequential shifting to quickly downshift during emergency braking in direct drive mode, thus preventing engine stalling due to slow downshifting speed and excessively low engine speed. Compared with related technologies, the beneficial effects of the downshift control device provided in this application are the same as those of the downshift control method provided in the above embodiments, and other technical features of this downshift control device are the same as those disclosed in the previous embodiment method, and will not be repeated here.

[0103] It should be understood that the various parts disclosed in this application can be implemented using hardware, software, firmware, or a combination thereof. In the description of the above embodiments, specific features, structures, materials, or characteristics can be combined in any suitable manner in one or more embodiments or examples.

[0104] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

[0105] This application provides a computer-readable storage medium having computer-readable program instructions (i.e., a computer program) stored thereon, the computer-readable program instructions being used to execute the downshift control method in the above embodiments.

[0106] The computer-readable storage medium provided in this application may be, for example, a USB flash drive, but is not limited to, electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices, or any combination thereof. More specific examples of computer-readable storage media may include, but are not limited to: electrical connections having one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof. In this embodiment, the computer-readable storage medium may be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, system, or device. The program code contained on the computer-readable storage medium may be transmitted using any suitable medium, including but not limited to: wires, optical cables, RF (Radio Frequency), etc., or any suitable combination thereof.

[0107] The aforementioned computer-readable storage medium may be included in the downshift control device; or it may exist independently and not assembled into the downshift control device.

[0108] The aforementioned computer-readable storage medium carries one or more programs that, when executed by the downshift control device, cause the downshift control device to: when it detects that the vehicle is in direct drive mode and is undergoing emergency braking, acquire the current driving gear of the vehicle; when it detects that the driving gear is a high gear, collect the current real-time vehicle speed and real-time acceleration of the vehicle; when the real-time vehicle speed is greater than a preset speed threshold and the real-time acceleration is less than a preset acceleration threshold, predict the target driving gear required by the vehicle; and based on the target driving gear, control the vehicle to downshift in advance.

[0109] Computer program code for performing the operations of this application can be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, and C++, and conventional procedural programming languages ​​such as the "C" language or similar programming languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving remote computers, the remote computer can be connected to the user's computer via any type of network—including a Local Area Network (LAN) or a Wide Area Network (WAN)—or can be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0110] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of this application. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0111] The modules described in the embodiments of this application can be implemented in software or hardware. The names of the modules do not necessarily limit the functionality of the unit itself.

[0112] The readable storage medium provided in this application is a computer-readable storage medium that stores computer-readable program instructions (i.e., a computer program) for executing the aforementioned downshift control method. This solves the technical problem of how to enable a vehicle with a hybrid transmission that only supports sequential shifting to quickly downshift during emergency braking in direct-drive mode, thus preventing engine stalling due to slow downshifting speed and excessively low engine speed. Compared with related technologies, the beneficial effects of the computer-readable storage medium provided in this application are the same as those of the downshift control method provided in the above embodiments, and will not be repeated here.

[0113] The above are merely optional 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 scope of this application.

Claims

1. A kick-down control method applied to a hybrid vehicle having a transmission capable of only sequential shifting, wherein, The downshift control method comprises: When detecting that the whole vehicle is in the direct drive mode and emergency braking is performed, obtaining a current driving gear of the whole vehicle; When detecting that the driving gear is a high-speed gear, collecting a current real-time vehicle speed and a real-time acceleration of the whole vehicle; When the real-time vehicle speed is greater than a preset speed threshold and the real-time acceleration is less than a preset acceleration threshold, predicting a target driving gear required by the whole vehicle; Based on the target driving gear, controlling the whole vehicle to perform downshift in advance.

2. The shift control method according to claim 1, wherein After the step of controlling the whole vehicle to perform downshift in advance based on the target driving gear, the method further comprises: When controlling the whole vehicle to perform downshift, controlling the whole vehicle to perform a gear pulling operation; When the whole vehicle completes the gear pulling operation, controlling the whole vehicle to shift to the target driving gear to complete downshift.

3. The shift control method according to claim 2, wherein After the step of controlling the whole vehicle to perform a gear pulling operation when controlling the whole vehicle to perform downshift, the method further comprises: When the whole vehicle starts to perform the gear pulling operation, adjusting the torque at both ends of the synchronizer through the generator, simultaneously obtaining a real-time torque difference corresponding to the torque at both ends of the synchronizer, and obtaining a current engine speed of the engine; When the engine speed is lower than a minimum engine speed corresponding to the direct drive mode, if the real-time torque difference is less than a first preset torque difference, controlling the gear shifting motor to perform gear pulling at a first preset speed to complete the gear pulling operation in advance.

4. The shift control method according to claim 3, wherein After the step of adjusting the torque at both ends of the synchronizer through the generator when the whole vehicle starts to perform the gear pulling operation, simultaneously obtaining a real-time torque difference corresponding to the torque at both ends of the synchronizer, and obtaining a current engine speed of the engine, the method further comprises: When the engine speed is not lower than the minimum engine speed, if the real-time torque difference is less than a second preset torque difference, controlling the gear shifting motor to perform gear pulling at a second preset speed to complete the gear pulling operation; Wherein, the second preset torque difference is lower than the first preset torque difference, and the second preset speed is lower than the first preset speed.

5. The shift control method according to claim 2, wherein After the step of controlling the whole vehicle to perform a gear pulling operation when controlling the whole vehicle to perform downshift, the method further comprises: When the whole vehicle completes the gear pulling operation, controlling the whole vehicle to enter an electronic continuously variable transmission (ECVT) mode.

6. The shift control method according to claim 1, wherein After the step of collecting a current real-time vehicle speed and a real-time acceleration of the whole vehicle when detecting that the driving gear is a high-speed gear, the method further comprises: When the real-time vehicle speed is less than the preset speed threshold, obtaining the target driving gear; Based on the target driving gear, controlling the whole vehicle to perform downshift.

7. The shift control method according to claim 1, wherein Before the step of predicting a target driving gear required by the whole vehicle when the real-time vehicle speed is greater than a preset speed threshold and the real-time acceleration is less than a preset acceleration threshold, the method further comprises: Based on the driving gear of the whole vehicle and a preset vehicle downshift condition table, obtaining the preset speed threshold and the preset acceleration threshold corresponding to the judgment of whether the current driving gear needs to be downshifted in advance.

8. A kickdown control device wherein, The downshift control device comprises: The gear acquisition module is configured to acquire a current driving gear of the vehicle when it is detected that the vehicle is in the direct drive mode and emergency braking is performed. The speed acquisition module is configured to collect a real-time vehicle speed and a real-time acceleration of the vehicle when it is detected that the driving gear is a high-speed gear. The gear prediction module is configured to predict a target driving gear required by the vehicle when the real-time vehicle speed is greater than a preset speed threshold and the real-time acceleration is less than a preset acceleration threshold. The gear control module is configured to control the vehicle to downshift in advance based on the target driving gear.

9. A kickdown control apparatus wherein, The downshift control device comprises a memory, a processor, and a downshift control program stored in the memory and executable on the processor, and the downshift control program is configured to implement the steps of the downshift control method according to any one of claims 1 to 7.

10. A storage medium, wherein, The storage medium is a computer readable storage medium, and the downshift control program is stored on the computer readable storage medium and implements the steps of the downshift control method according to any one of claims 1 to 7 when executed by a processor.

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