Method for mitigating nose-up during acceleration of electric vehicle, and controller

Abstract

A method for mitigating nose-up during acceleration of an electric vehicle. The method for mitigating nose-up during acceleration is used for controlling, when an electric vehicle accelerates in a forward-gear idling condition, the output torque of a driving electric motor of the electric vehicle on the basis of the strokes of an accelerator pedal and a brake pedal of the electric vehicle. The method comprises: at a first moment, the stroke of a brake pedal being greater than a first preset brake pedal stroke, and controlling a driving electric motor to output an idling torque; at a second moment after the first moment, the stroke of the brake pedal being reduced to be less than a second preset brake pedal stroke, and controlling the driving electric motor to output a first torque, wherein the first torque is greater than the idling torque; and at a third moment after the second moment, the stroke of an accelerator pedal being greater than a first preset accelerator pedal stroke after the brake pedal is fully released, and controlling the driving electric motor to output a second torque to drive wheels to rotate, wherein the second torque is greater than the first torque. The control method can reduce the acceleration jerk rate of a vehicle, thereby better suppressing vehicle nose-up during acceleration.

Description

A method and controller for mitigating nose-up during electric vehicle start-up

[0001] This application claims priority to Chinese Patent Application No. 202510014586.5, filed on January 3, 2025, entitled "A Method and Controller for Alleviating Head-Up During Electric Vehicle Start-up", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of electric vehicle technology, and in particular to a method and controller for mitigating head-up during electric vehicle start-up. Background Technology

[0003] With the widespread use of electric vehicles, people are placing increasingly higher demands on their performance. One issue is that during initial acceleration, the rapid increase in motor torque can easily lead to a sharp nose-up phenomenon in electric vehicles. This sharp nose-up can result in a poor driving and riding experience and even safety issues. Currently, existing methods for mitigating nose-up during electric vehicle acceleration are not quick enough and have limited applicability in various road scenarios. Therefore, providing a method for quickly mitigating nose-up during electric vehicle acceleration that is applicable to a wide range of road conditions is precisely what the industry needs. Summary of the Invention

[0004] This application provides a method and controller for mitigating the nose-up phenomenon of electric vehicles during start-up, which can more quickly reduce the nose-up phenomenon of electric vehicles when starting to drive in various road scenarios.

[0005] To achieve the above objectives, this application provides the following start-up lift-off mitigation method and controller.

[0006] In a first aspect, this application provides a method for mitigating the lift-off during start-up of an electric vehicle. This method controls the output torque of the electric vehicle's drive motor based on the travel of the accelerator and brake pedals when the electric vehicle starts from a forward gear and is idling. The method includes the following steps:

[0007] First, at the first instant, the brake pedal travel exceeds a first preset brake pedal travel, controlling the drive motor to output idle torque. Second, at the second instant after the first instant, the brake pedal travel decreases to less than a second preset brake pedal travel, controlling the drive motor to output a first torque, which is greater than the idle torque. Third, at the third instant after the second instant, after the brake pedal is fully released, the accelerator pedal travel exceeds a first preset accelerator pedal travel, controlling the drive motor to output a second torque to drive the wheels to rotate, which is greater than the first torque.

[0008] Based on the above control method, when an electric vehicle is in forward gear and starts from idle after braking and deceleration, the starting control is performed according to the above control method. Before the accelerator pedal is pressed, the drive motor can apply a first torque to the vehicle as a starting preparation torque. This allows the output torque of the drive motor to increase from the first torque when the accelerator pedal is pressed, reducing the rate of change of the output torque and thus slowing down the rate of change of the vehicle's starting acceleration. This effectively suppresses the vehicle's nose-up phenomenon during starting.

[0009] In one embodiment, the method for mitigating the start-up lift of an electric vehicle further includes controlling the torque output of the drive motor to be equal to a first torque at any time between a second and a third time.

[0010] Based on the above implementation method, when an electric vehicle applies torque to the vehicle using the drive motor as a starting preparation torque before the accelerator pedal is pressed, maintaining the applied preparation torque at the first torque can reduce the frequency of changes in the starting preparation torque, simplify the control frequency requirements of the motor output torque, make the output starting preparation torque more accurate, better meet the torque change requirements after the accelerator pedal is pressed, and better suppress the starting lift phenomenon.

[0011] In one embodiment, the method for mitigating the start-up lift of an electric vehicle further includes controlling the torque output of the drive motor to be greater than a first torque and less than a second torque at any time between a second time and a third time.

[0012] Based on the above implementation method, when applying torque to the electric vehicle as a starting preparation torque before pressing the accelerator pedal, the applied torque is kept between the first torque and the second torque, and the motor output torque is kept within an appropriate torque range. This can appropriately reduce the precise control of the motor torque, which is more conducive to the rapid implementation of the control method, thereby better improving the practicality of the electric vehicle starting lift-off phenomenon.

[0013] In one implementation, the method for mitigating the start-up lift of an electric vehicle further includes, between a second and a third time point, controlling the torque output of the drive motor to be inversely proportional to the brake pedal travel.

[0014] Based on the above implementation method, when applying torque to the electric vehicle as a starting preparation torque before pressing the accelerator pedal, the applied torque is kept between the first torque and the second torque, and gradually increases as the brake pedal travel decreases. This method of applying preparation torque changes as the brake pedal travel recovers, which can respond to the starting change requirements of the electric vehicle in real time, thereby better improving the practicality of reducing the nose-up phenomenon when starting the electric vehicle.

[0015] In one embodiment, the method for mitigating the start-up lift-off of an electric vehicle further includes controlling the drive motor to output a third torque at a fourth time after the third time, where the acceleration travel rate of the accelerator pedal is greater than the first accelerator pedal travel rate, and the third torque is less than the output torque indicated by the accelerator pedal at the fourth time.

[0016] Based on the above implementation method, when an electric vehicle starts by pressing the accelerator pedal and applies driving torque to the vehicle using the drive motor, the torque output by the drive motor is appropriately reduced to less than the output torque indicated by the accelerator pedal at the same time by judging the rate of increase of the acceleration stroke of the accelerator pedal. This balances power and comfort by reducing the torque output of the drive motor, which can control the starting acceleration of the electric vehicle within a comfortable range and further control the starting acceleration of the electric vehicle, thereby further accelerating and reducing the starting lift-up phenomenon of the electric vehicle.

[0017] In one embodiment, the method for mitigating head-up during start-up of an electric vehicle further includes the following situations: when the electric vehicle is traveling uphill, the third torque output by the drive motor is proportional to the gradient of the uphill road; when the electric vehicle is traveling downhill, the third torque output by the drive motor is inversely proportional to the gradient of the downhill road.

[0018] Based on the above implementation method, when an electric vehicle starts by pressing the accelerator pedal, the drive motor applies driving torque to the vehicle. The torque output by the drive motor is controlled to be appropriately less than the output torque indicated by the accelerator pedal at the same time. It is also related to the slope of the road. The output torque is appropriately increased on uphill roads and appropriately decreased on downhill roads. This can better match the start-up and lift-off control in uphill and downhill road scenarios, and control the start-up and lift-off in uphill and downhill road scenarios more quickly, making the control method of electric vehicles more practical in various scenarios.

[0019] In one embodiment, the method for mitigating the head-up during start-up of an electric vehicle further includes controlling the third torque output by the drive motor to be proportional to the coefficient of adhesion of the low-friction surface when the electric vehicle starts on a low-friction surface.

[0020] Based on the above implementation method, when an electric vehicle starts by pressing the accelerator pedal and applies driving torque to the vehicle using the drive motor, the torque output by the drive motor is controlled to be appropriately less than the output torque indicated by the accelerator pedal at the same time. At the same time, the output torque on low-friction surfaces such as icy or slippery surfaces is also limited. By appropriately reducing the output torque as the road surface adhesion coefficient decreases, the starting lift control can be better matched to low-friction road scenarios, preventing the electric vehicle from slipping when starting lift control on low-friction surfaces, thus making the starting lift control method safer.

[0021] In one embodiment, the method for mitigating the start-up lift-off of an electric vehicle further includes, after a fourth moment, the rate of increase in the acceleration travel of the accelerator pedal is greater than the rate of increase in the first accelerator pedal travel; at a fifth moment after the fourth moment, the acceleration of the electric vehicle is equal to a first preset acceleration; controlling the drive motor to output a fourth torque, the fourth torque being less than the output torque indicated by the accelerator pedal at the fourth moment; after the fifth moment, the acceleration of the electric vehicle is greater than the first preset acceleration; the acceleration travel of the accelerator pedal increases; and controlling the drive motor to maintain the output of the fourth torque.

[0022] Based on the above implementation method, after the electric vehicle starts and the accelerator pedal is pressed, the torque output of the electric vehicle's drive motor is controlled by this start-up lift-up control method, which limits the acceleration of the electric vehicle to the acceleration range required for comfortable driving, thereby preventing the electric vehicle from over-accelerating and enabling the start-up lift-up phenomenon of the electric vehicle to be controlled quickly and effectively.

[0023] In one embodiment, the start-up lift-off mitigation method is used to adjust the suspension of the electric vehicle when the electric vehicle is starting in forward gear. The start-up lift-off mitigation method further includes controlling the suspension controller to increase the suspension stiffness or damping of the electric vehicle at the second moment mentioned above.

[0024] Based on the above implementation method, when an electric vehicle starts in forward gear, this start-up lift mitigation method sends a command to the suspension controller of the electric vehicle at the second moment to instruct the suspension controller to increase the suspension stiffness or damping of the electric vehicle. Then, at the third moment when the electric vehicle depresses the accelerator pedal to start, the suspension of the electric vehicle has become stiffer, which can further promote the rigid connection between the electric vehicle body and chassis, thereby reducing the inconsistent movement of the body and chassis during acceleration and slowing down the start-up lift of the vehicle.

[0025] In one embodiment, the start-up lift-off mitigation method further includes, at the aforementioned second moment, controlling the suspension controller to lower the suspension height of the electric vehicle.

[0026] Based on the above implementation method, the electric vehicle sends a command to the suspension controller of the electric vehicle at the second moment to instruct the suspension controller to lower the suspension height of the electric vehicle, thereby reducing the overall height of the electric vehicle, thereby reducing the shaking caused by inconsistent movement of the body and chassis during acceleration, and further reducing the vehicle's nose-up during start-up.

[0027] Secondly, this application provides another method for mitigating the lift-off during electric vehicle start-up. This method is used to control the output torque of the electric vehicle's drive motor based on the travel of the accelerator and brake pedals when starting the electric vehicle from a neutral, stationary position. The method includes the following steps:

[0028] First, at the sixth moment, the brake pedal travel is zero and the electric vehicle is engaged in forward gear, controlling the drive motor to output the fifth torque;

[0029] Secondly, at the seventh moment after the sixth moment, the travel of the accelerator pedal is greater than the second preset accelerator pedal travel, and the drive motor is controlled to output the sixth torque to drive the wheels to rotate. The sixth torque is greater than the fifth torque.

[0030] Based on the above control method, when the electric vehicle is in neutral and stationary, it is controlled to start. Before the accelerator pedal is pressed, the drive motor applies a fifth torque as a starting preparation torque to the vehicle when it is engaged in forward gear. This causes the output torque of the drive motor to increase from the fifth torque when the accelerator pedal is pressed, reducing the rate of change of the output torque and thus slowing down the rate of change of the vehicle's starting acceleration. This effectively suppresses the nose-up phenomenon when the vehicle starts in this state.

[0031] In one embodiment, the start-up lift-off mitigation method further includes controlling the torque output of the drive motor to be equal to the fifth torque or controlling the torque output of the drive motor to be greater than the fifth torque and less than the sixth torque at any time between the sixth time and the seventh time.

[0032] Based on the above implementation methods, when an electric vehicle applies torque to the vehicle using the drive motor as a starting preparation torque before the accelerator pedal is depressed, the applied starting preparation torque can be controlled according to actual design needs. If the applied preparation torque is maintained at the fifth torque level, the frequency of changes in the starting preparation torque can be reduced, making the output starting preparation torque more precise and better meeting the torque change requirements after the accelerator pedal is depressed, thus better suppressing the start-up lift-off phenomenon. If the applied torque is maintained between the fifth and sixth torque levels, ensuring the motor output torque meets an appropriate torque range, the precision control of the motor torque can be appropriately reduced, facilitating the rapid implementation of the control method and further improving the practicality of mitigating the start-up lift-off phenomenon in electric vehicles.

[0033] In one embodiment, the start-up lift-off mitigation method further includes controlling the fifth torque output by the drive motor to be proportional to the slope of the uphill road when the electric vehicle is traveling uphill; and controlling the fifth torque output by the drive motor to be inversely proportional to the slope of the downhill road when the electric vehicle is traveling downhill.

[0034] Based on the above implementation method, when an electric vehicle applies a fifth torque to the vehicle using the drive motor as a starting preparation torque before the accelerator pedal is pressed, the preparation torque output by the drive motor is controlled to be related to the slope of the road. The preparation torque is appropriately increased on uphill roads and appropriately decreased on downhill roads, which can control the start-up and lift-off of the vehicle more quickly in uphill and downhill road scenarios, making the control method of electric vehicles more practical in various scenarios.

[0035] In one embodiment, the start-up lift-off mitigation method further includes controlling the fifth and sixth torques output by the drive motor to be proportional to the adhesion coefficient of the low-adhesion surface when the electric vehicle starts on the low-adhesion surface.

[0036] Based on the above implementation method, the electric vehicle also limits the preparatory torque and output torque on low-adhesion surfaces such as icy or slippery surfaces when starting. By appropriately reducing the preparatory torque and output torque as the road adhesion coefficient decreases, the starting pitch control can be better matched to low-adhesion road scenarios, preventing the electric vehicle from slipping when starting pitch control on low-adhesion surfaces, thus making the starting pitch control method safer.

[0037] Thirdly, this application provides a controller for controlling the forward start of an electric vehicle according to the start-up lift-off mitigation method provided in the first and second aspects. The controller is also used to receive DC power from the electric vehicle's power battery and convert it into AC power to drive the electric vehicle's drive motor to rotate.

[0038] The controller provided in the third aspect integrates the vehicle start-up and lift-off control functions and drive motor control functions of electric vehicles, reducing the transmission and conversion time of output torque commands, accelerating the control of electric vehicle start-up and lift-off reduction, and reducing the size of the controller on the electric vehicle, saving installation space and reducing costs. Attached Figure Description

[0039] Figure 1 is a structural schematic diagram of an electric vehicle provided in an embodiment of this application;

[0040] Figure 2 is a schematic diagram of a method for slowing down the head-up movement of an electric vehicle according to an embodiment of this application;

[0041] Figure 3 is a schematic diagram of a method for slowing down the head-up movement of an electric vehicle according to an embodiment of this application;

[0042] Figure 4 is a schematic diagram of a method for slowing down the start-up and head-up of an electric vehicle according to an embodiment of this application;

[0043] Figure 5 is a schematic diagram of a method for slowing down the head-up movement of an electric vehicle according to an embodiment of this application;

[0044] Figure 6 is a schematic diagram of a method for slowing down the start-up and head-up movement of an electric vehicle according to an embodiment of this application;

[0045] Figure 7 is a schematic diagram of a method for slowing down the start-up and nose-up of an electric vehicle according to an embodiment of this application;

[0046] Figure 8 is a schematic diagram of a method for slowing down the start-up and head-up of an electric vehicle according to an embodiment of this application;

[0047] Figure 9 is a schematic diagram of a method for slowing down the start-up and head-up of an electric vehicle according to an embodiment of this application;

[0048] Figure 10 is a schematic diagram of a method for slowing down the start-up of an electric vehicle according to an embodiment of this application;

[0049] Figure 11 is a schematic diagram of a method for slowing down the start-up of an electric vehicle according to an embodiment of this application;

[0050] Figure 12 is a schematic diagram of a method for slowing down the start-up of an electric vehicle according to an embodiment of this application;

[0051] Figure 13 is a schematic diagram of a method for slowing down the start-up of an electric vehicle according to an embodiment of this application. Detailed Implementation

[0052] The technical solutions in the embodiments of this application will now be described with reference to the accompanying drawings.

[0053] It should be noted that the terms "in one embodiment" or "exemplary" in this application are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "in one embodiment" or "exemplary" in this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "in one embodiment" or "exemplary" is intended to present the relevant concepts in a specific manner.

[0054] The present application will now be described in detail with reference to the accompanying drawings and embodiments.

[0055] Electric vehicles are powered by drive motors. Because drive motors have a relatively fast torque ramp-up speed, and the vehicle suspension is made of elastic elements, the lower body accelerates rapidly under the action of the drive motor, while the upper body cannot respond quickly enough. The upper body experiences a backward inertial force, causing the vehicle's posture to become higher in the front and lower in the rear. Therefore, electric vehicles often experience a relatively sharp nose-up phenomenon during start-up, affecting the driving experience and potentially causing safety issues. This application provides a method and controller for mitigating nose-up during start-up in electric vehicles, aiming to more quickly reduce nose-up during start-up in various road scenarios while maintaining power performance and improving the comfortable driving experience.

[0056] As shown in Figure 1, an electric vehicle 10 typically includes a drive motor 20, a power battery 30, wheels 40, a controller 50, a suspension controller 60, a suspension 70, an accelerator pedal 80, a brake pedal 90, and a braking device 91. The suspension controller 60 is used to control the stiffness, damping, and height of the suspension 70, etc. The braking force of the braking device 91 is proportional to the travel of the brake pedal 90.

[0057] In one embodiment, the controller 50 of the electric vehicle 10 receives DC power from the power battery 30 and converts it into AC power to drive the drive motor 20 of the electric vehicle 10 to rotate. The controller 50 is also used to provide a method for relieving the starting lift of the electric vehicle 10 to control the electric vehicle to start forward or reverse. That is, the starting lift relief control method is integrated into the motor controller to achieve integrated control.

[0058] Based on the above embodiments, the controller 50 integrates the vehicle start-up and lift-off control functions and drive motor control functions of the electric vehicle 10, which shortens the transmission path of the torque output command, reduces the transmission and conversion time of the output torque command, accelerates the start-up and lift-off control of the electric vehicle 10, and reduces the size of the controller 50 on the electric vehicle 10, saving vehicle installation space and reducing costs.

[0059] In one embodiment, the control method for easing the start-up lift of the electric vehicle 10 is integrated into any one of the controllers, such as the vehicle controller, chassis domain controller, and smart cockpit controller. This reduces the transmission of control commands such as acceleration signals, braking signals, and gear signals, thereby speeding up the control of the start-up lift of the electric vehicle 10. It also reduces the size of the controller 50 of the electric vehicle 10, saving vehicle installation space and reducing costs.

[0060] The controller 50 described above can remain unchanged in terms of hardware signal interface, or a set of CAN-high and CAN-Low interface pins can be added as needed to provide a dedicated interface for the start-up lift-off control method, thereby improving control speed, preventing signal interference, and ensuring safety.

[0061] Based on the aforementioned architecture of the electric vehicle 10, the starting lift-off mitigation method of this application will be described below with reference to specific embodiments.

[0062] This application provides a start-up lift-off mitigation method for an electric vehicle 10. This method controls the output torque of the drive motor 20 of the electric vehicle 10 based on the travel of the accelerator pedal 80 and brake pedal 90 when the electric vehicle 10 starts from a forward gear and is idling. The start-up lift-off mitigation method includes the following steps:

[0063] First, at the first instant, the travel of the brake pedal 90 exceeds the first preset brake pedal travel, controlling the drive motor 20 to output idle torque. Second, at the second instant after the first instant, the travel of the brake pedal 90 is less than the second preset brake pedal travel, controlling the drive motor 20 to output a first torque, which is greater than the idle torque. Third, at the third instant after the second instant, after the brake pedal 90 is fully released, the travel of the accelerator pedal 80 exceeds the first preset accelerator pedal travel, controlling the drive motor 20 to output a second torque to drive the wheel 40 to rotate, which is greater than the first torque.

[0064] Figure 2 shows a starting output torque control diagram according to an embodiment of this application. In the upper part of Figure 2, the left side is the curve of the braking stroke and the right side is the curve of the acceleration stroke. The following figures also represent the same meaning.

[0065] In one embodiment, when the electric vehicle 10 is in motion, the driver brakes the vehicle using the brake pedal 90 to gradually decelerate it to a stop, or due to inertia, at a very low speed, such as less than 3 km / h. At this time, the electric vehicle 10 is in drive gear and the drive motor 20 is not used to drive the electric vehicle 10 forward. The electric vehicle 10 is in drive gear idling condition, a typical scenario being when braking in advance while waiting at a traffic light. After this, when the electric vehicle 10 is ready to move forward and accelerate, the driver will gradually release the brake pedal 90 and then press the accelerator pedal 80 to accelerate from a standstill. The rotary transformer of the drive motor 20 will also experience positive acceleration growth.

[0066] As shown in Figure 2, when the electric vehicle 10 starts moving forward after braking in gear, firstly at the first moment t1, when the travel of the brake pedal 90 of the electric vehicle 10 is greater than the first preset brake pedal travel S11, the electric vehicle 10 controls the drive motor 20 to output idle torque T0. T0 can be 0 Nm, or a small torque of 0.5 Nm set according to actual needs, such as noise reduction and tooth-fitting torque. Secondly, at the second moment t2 after the first moment t1, when the travel of the brake pedal 90 of the electric vehicle 10 gradually returns to less than the second preset brake pedal travel S21, the electric vehicle 10 prepares to start. It controls the drive motor 20 to output a first torque T1. The first torque T1 is a small torque, such as 10 Nm. The first torque T1 is greater than the idle torque T0, but the first torque T1 cannot drive the electric vehicle 10 to start on its own. At the third time t3, following the second time t2, after the brake pedal 90 of electric vehicle 10 is fully released (i.e., its travel is 0), the travel S3 of its accelerator pedal 80 is greater than the first preset accelerator pedal travel S31. Electric vehicle 10 then controls the drive motor 20 to output a second torque T2 to drive the wheels 40 to rotate. The second torque T2 is the driving torque, set according to specific factors such as vehicle weight, load, and road conditions. The second torque T2 is greater than the first torque T1. It should be noted that before the third time t3, the torque output by the drive motor 20 cannot independently drive electric vehicle 10 to start moving forward. S11 is a larger travel value, such as 50% of the full brake pedal travel, while S21 and S31 are smaller travel values, such as 5% of the full travel. The times t1, t2, t3, torques T0, T1, T2, and travels S11, S21, S31 are not fixed values ​​used for all vehicle models, but are matched and calibrated to be specific to each vehicle.

[0067] Regarding the above embodiments, it should be noted that the above embodiments are described under the condition of human driving. If it is in the case of autonomous driving, the brake pedal travel, accelerator pedal travel, etc. mentioned in the above embodiments may be electronic travel signals rather than specific visible displacement travel signals. Other related variables may also have similar situations, but this is the same as the inventive concept and beneficial effects of this application. It is just that the specific manifestation is different and cannot be attributed to different inventions.

[0068] Based on the control method of the above embodiments, when the electric vehicle 10 is in forward gear and starts from idling after braking and deceleration, starting control is performed according to the above control method. Before the accelerator pedal 80 is pressed, the drive motor 20 applies a first torque T1 to the vehicle. The torque output by the drive motor 20 between t2 and t3 is used as the starting preparation torque. This allows the output torque of the drive motor 20 to increase from the preparation torque when the accelerator pedal 80 is pressed, reducing the rate of change of the drive output torque and thus slowing down the rate of change of the starting acceleration of the electric vehicle 10. This allows the starting nose-up phenomenon of the electric vehicle 10 to be suppressed more quickly.

[0069] The method for mitigating the start-up lift of the electric vehicle 10 further includes controlling the torque output of the drive motor 20 to be equal to the first torque T1 at any time between the second time t2 and the third time t3.

[0070] In one embodiment, as shown in FIG2, the electric vehicle 10 needs to control the torque output of the drive motor 20 before the driver presses the accelerator pedal 80. Before the driver presses the accelerator pedal 80, at any time between the second time t2 and the third time t3, the electric vehicle 10 controls the drive motor 20 to make its output torque equal to the first torque T1. That is, between the second time t2 and the third time t3, the drive motor 20 is controlled to maintain the output torque of T1 unchanged.

[0071] Based on the above specific embodiments, when the electric vehicle 10 applies torque to the electric vehicle 10 using the drive motor 20 as the starting preparation torque before the accelerator pedal 80 is pressed, the applied preparation torque is kept at the first torque T1. This can reduce the frequency of changes in the starting preparation torque, reduce the frequency requirements for controlling the output torque, make the output starting preparation torque more accurate, better meet the torque change requirements after the accelerator pedal 80 is pressed, and better suppress the starting lift phenomenon.

[0072] The method for mitigating the start-up lift of the electric vehicle 10 further includes controlling the torque output of the drive motor 20 to be greater than the first torque T1 and less than the second torque T2 at any time between the second time t2 and the third time t3.

[0073] In one embodiment, as shown in FIG3, the electric vehicle 10 needs to control the torque output of the drive motor 20 before the driver presses the accelerator pedal 80. At any time between the second time t2 and the third time t3 before the driver presses the accelerator pedal 80, the electric vehicle 10 controls the drive motor 20 to make its output torque greater than the first torque T1 and less than the second torque T2. That is, between the second time t2 and the third time t3, the torque output of the drive motor 20 is maintained between the first torque T1 and the second torque T2. FIG3 is an example of one of the conditions.

[0074] Based on the above specific embodiments, when the electric vehicle 10 applies torque as a starting preparation torque before the accelerator pedal 80 is pressed, the applied torque is kept within the torque range between the first torque T1 and the second torque T2. This can appropriately reduce the precise control of torque by the drive motor 20, which can also be achieved on a motor controller with general control precision. This is more conducive to the rapid implementation of the control method, thereby better improving the practicality of the electric vehicle 10 in reducing the nose-up phenomenon during start-up.

[0075] The method for mitigating the start-up lift of the electric vehicle 10 further includes controlling the torque output of the drive motor 20 to be inversely proportional to the travel of the brake pedal 90 between the second time t2 and the third time t3.

[0076] In one embodiment, as shown in FIG3, the electric vehicle 10 needs to control the torque output of the drive motor 20 before the driver presses the accelerator pedal 80. Before the driver presses the accelerator pedal 80, the torque output of the drive motor 20 between the second time t2 and the third time t3 is inversely proportional to the travel of the brake pedal 90. That is, when the travel of the brake pedal 90 decreases, the braking force of the braking device 91 weakens accordingly. When the electric vehicle 10 has a clear tendency to start, the torque output of the drive motor 20 increases accordingly.

[0077] Based on the above specific embodiments, when the electric vehicle 10 applies torque to the vehicle as a starting preparation torque before the driver presses the accelerator pedal 80 to start, the applied torque is kept between the first torque T1 and the second torque T2, and gradually increases as the travel of the brake pedal 90 decreases. This method of applying preparation torque changes as the travel of the brake pedal 90 recovers, which can respond in real time to the starting trend of the electric vehicle 10, thereby better improving the practicality of the electric vehicle 10 in reducing the starting lift phenomenon.

[0078] The method for mitigating the head-up during start-up of the electric vehicle 10 also includes controlling the drive motor 20 to output a third torque T3 at a rate greater than the first accelerator pedal travel rate at a fourth time t4 after the third time t3, which is less than the output torque indicated by the accelerator pedal 80 at the fourth time t4.

[0079] In one embodiment, as shown in Figure 4, after the driver presses the accelerator pedal 80, the electric vehicle 10 needs to control the torque output of the drive motor 20. After the third time t3, the rate at which the driver presses the accelerator pedal 80 increases. At the fourth time t4 after the third time t3, the acceleration stroke S4 of the accelerator pedal 80 increases at a rate greater than the first accelerator pedal stroke rate Sv1. That is, the electric vehicle 10 is in a state of increasing starting acceleration. At this time, the electric vehicle 10 controls the drive motor 20 to output a third torque T3. The third torque T3 is not equal to the output torque indicated by the accelerator pedal 80. In order to reduce acceleration, the third torque T3 is controlled to be less than the output torque T30 indicated by the accelerator pedal 80 at the fourth time t4. The first accelerator pedal stroke rate Sv1 is a relatively fast accelerator pedal stroke rate, such as 20 mm / s.

[0080] Based on the above specific embodiments, when the electric vehicle 10 applies driving torque to the electric vehicle 10 by the drive motor 20 after the accelerator pedal 80 is pressed to start, the torque output by the drive motor 20 is controlled to be appropriately less than the output torque indicated by the accelerator pedal 80 at the same time by judging the rate of increase of the acceleration stroke of the accelerator pedal 80. By reducing the torque output by the drive motor 20 while taking into account both power and comfort, the starting acceleration of the electric vehicle 10 can be controlled within a comfortable range, further controlling the starting acceleration of the electric vehicle 10, thereby accelerating and reducing the starting lift phenomenon of the electric vehicle 10.

[0081] The method for mitigating the nose-up during start-up of the electric vehicle 10 also includes increasing the acceleration travel rate of the accelerator pedal 80 at a rate greater than the first accelerator pedal travel rate Sv1 after the fourth time t4. At the fifth time t5 after the fourth time t4, the acceleration of the electric vehicle 10 is equal to the first preset acceleration a1. The drive motor 20 is then controlled to output a fourth torque T4. The fourth torque T4 is less than the output torque indicated by the accelerator pedal 80 at the fourth time t4. After the fifth time t5, the acceleration of the electric vehicle 10 is greater than the first preset acceleration a1, and the acceleration travel of the accelerator pedal 80 increases. The drive motor 20 is then controlled to maintain the output of the fourth torque T4. The first preset acceleration a1 is a relatively large acceleration that affects the nose-up during start-up of the electric vehicle 10, such as 2 m / s^2. However, the first preset acceleration a1 is not a constant value and needs to be set according to the actual nose-up situation during start-up of the electric vehicle 10.

[0082] In one embodiment, as shown in Figure 5, after the fourth time point t4, the electric vehicle 10 continues to accelerate from a standstill. The rate of increase in the acceleration travel of the accelerator pedal 80 is greater than the first accelerator pedal travel rate Sv1, at which point the acceleration of the electric vehicle 10 increases. At the fifth time point t5, after the fourth time point t4, when the acceleration of the electric vehicle 10 equals the first preset acceleration a1, it indicates that the electric vehicle 10 has accelerated quite aggressively, and the electric vehicle 10 needs to limit its drive torque output. At this time, the drive motor 20 is controlled to output a fourth torque T4, which is less than the output torque indicated by the accelerator pedal 80 at the fourth time point t4. After the fifth time point t5, the acceleration of the electric vehicle 10 is greater than the first preset acceleration a1, and the driver continues to depress the accelerator pedal 80, increasing the acceleration travel of the accelerator pedal 80. At this point, the electric vehicle 10 can no longer increase its torque output, so the drive motor 20 is controlled to maintain the output of the fourth torque T4 unchanged until the driver reduces the travel of the accelerator pedal 80 to a comfortable driving range.

[0083] Based on the above specific embodiments, after the electric vehicle 10 presses the accelerator pedal 80 to start, the torque output of the drive motor 20 of the electric vehicle 10 is controlled by the start-up lift-up control method, so as to limit the acceleration of the electric vehicle 10 within the acceleration range required for comfortable driving, thereby preventing the electric vehicle 10 from over-accelerating and making the start-up lift-up phenomenon of the electric vehicle 10 quickly and effectively controlled.

[0084] The method for mitigating head-up during start-up of the electric vehicle 10 further includes: when the electric vehicle 10 is traveling uphill, the third torque T3 output by the drive motor 20 is proportional to the slope of the uphill road; when the electric vehicle 10 is traveling downhill, the third torque T3 output by the drive motor 20 is inversely proportional to the slope of the downhill road.

[0085] Based on the same concept, the method for mitigating head-up during start-up of the electric vehicle 10 may also include: when the electric vehicle 10 is traveling uphill, controlling the idle torque T0, first torque T1, second torque T2, and fourth torque T4 output by the drive motor 20 to be proportional to the slope of the uphill road; when the electric vehicle 10 is traveling downhill, controlling the idle torque T0, first torque T1, second torque T2, and fourth torque T4 output by the drive motor 20 to be inversely proportional to the slope of the downhill road.

[0086] In one embodiment, when the electric vehicle 10 is starting uphill, due to the drag of the weight component of the electric vehicle 10, the output torque of the electric vehicle 10 can be appropriately increased during the start-up lift control to obtain the same driving experience as when starting on a flat road. As shown in Figure 6, when the electric vehicle 10 is driving uphill, the idle torque T0, the first torque T1, the second torque T2, the third torque T3, and the fourth torque T4 output by the drive motor 20 are proportional to the slope of the uphill road and are appropriately increased as the slope increases to overcome the drag effect of the weight component on the slope. Therefore, the above torques are appropriately increased to T01, T11, T21, T31, and T41 respectively. As shown in Figure 7, when the electric vehicle 10 is driving downhill, the idle torque T0, the first torque T1, the second torque T2, the third torque T3, and the fourth torque T4 output by the drive motor 20 are inversely proportional to the slope of the downhill road and decrease appropriately as the slope increases, in order to reduce the acceleration effect of the gravity component on the slope. Therefore, the above torques are appropriately reduced to T02, T12, T22, T32, and T42 respectively.

[0087] Based on the specific embodiments described above, when the electric vehicle 10 performs start-up lift-off control, it is related to the slope of the road. The output torque is appropriately increased on uphill roads and appropriately decreased on downhill roads. This can better match the start-up lift-off control in uphill and downhill road scenarios, control the start-up lift-off in uphill and downhill road scenarios more quickly, and obtain the same driving experience as when starting on a flat road. This makes the control method of the electric vehicle more practical in various application scenarios.

[0088] The method for mitigating head-up during start-up of the electric vehicle 10 further includes controlling the third torque T3 output by the drive motor 20 to be proportional to the adhesion coefficient of the low-adhesion surface when the electric vehicle 10 starts on a low-adhesion surface.

[0089] Based on the same concept, the method for mitigating the head-up during start-up of the electric vehicle 10 may also include: when the electric vehicle 10 starts on a low-friction surface, controlling the idle torque T0, the first torque T1, the second torque T2 and the fourth torque T4 output by the drive motor 20 to be proportional to the adhesion coefficient of the low-friction surface.

[0090] In one embodiment, when the electric vehicle 10 is on a low-friction surface such as an icy or slippery surface, the grip of the electric vehicle 10 will decrease due to the reduced coefficient of adhesion. Therefore, it is necessary to control the output torque of the electric vehicle 10 during start-up and lift-off control. Similarly, as shown in Figure 7, when the electric vehicle 10 is driving on a low-friction surface, the idle torque T0, the first torque T1, the second torque T2, the third torque T3, and the fourth torque T4 output by the drive motor 20 are proportional to the coefficient of adhesion of the low-friction surface and are appropriately reduced as the coefficient of adhesion decreases to prevent the electric vehicle 10 from accelerating too quickly and causing the wheels 40 to slip. Therefore, for example, the above torques are appropriately reduced to T02, T12, T22, T32, and T42 respectively.

[0091] Based on the above embodiments, when the electric vehicle 10 is driving on a low-friction surface such as an icy or slippery surface, the output torque of the drive motor 20 is limited. As the road surface adhesion coefficient decreases, the output torque is appropriately reduced, which can better match the start-up and lift-up control in low-friction road scenarios, prevent the electric vehicle 10 from slipping when starting and lifting up on a low-friction surface, and make the start-up and lift-up control method safer.

[0092] The start-up lift-off relief method for electric vehicle 10 is used to adjust the suspension 70 of electric vehicle 10 when electric vehicle 10 is starting in forward gear. At the second moment t2 mentioned above, the suspension controller 60 is controlled to increase the stiffness or damping of the suspension 70 of electric vehicle 10.

[0093] In one embodiment, as shown in Figure 8, when the electric vehicle 10 is in a forward gear and starting, the starting lift of the electric vehicle 10 can be accelerated by adjusting the stiffness and damping of the suspension 70. At the second moment t2, the electric vehicle 10 instructs the suspension controller 60 to increase the stiffness or damping of the suspension 70, with the stiffness changing from K1 to K2 and the damping changing from C1 to C2. The stiffened suspension 70 enhances the rigid connection between the vehicle body and chassis, reducing the relative motion between them. It should be noted that Figure 8 shows the trend of stiffness and damping changes, not specific values.

[0094] Based on the specific embodiments described above, when the electric vehicle 10 starts in forward gear, it utilizes this start-up lift mitigation method. At the second moment t2, a command is sent to the suspension controller 60 of the electric vehicle 10 to instruct the suspension controller 60 to increase the stiffness or damping of the suspension 70 of the electric vehicle 10. Then, at the third moment t3, when the electric vehicle 10 depresses the accelerator pedal 80 to start, the suspension of the electric vehicle 10 has already become stiff, which can further promote the rigid connection between the body and chassis of the electric vehicle 10, thereby reducing the inconsistent movement of the body and chassis during acceleration and mitigating the start-up lift of the vehicle.

[0095] The method for mitigating the nose-up during start-up of the electric vehicle 10 also includes, at the second moment t2 mentioned above, controlling the suspension controller 60 to lower the height of the suspension 70 of the electric vehicle.

[0096] In one embodiment, the control of the suspension controller 60 of the electric vehicle 10 to lower the height of the suspension 70 of the electric vehicle at the second moment t2 can lower the center of gravity of the electric vehicle 10, thereby further reducing the inconsistent movement of the vehicle body and chassis during acceleration.

[0097] Based on the above embodiments, at the second moment t2, the electric vehicle 10 sends a command to the suspension controller 60 of the electric vehicle 10 to instruct the suspension controller 60 to lower the suspension height of the electric vehicle 10, thereby reducing the overall height of the electric vehicle 10, thereby reducing the shaking caused by inconsistent movement of the body and chassis during acceleration, and further reducing the vehicle's nose-up during start-up.

[0098] Furthermore, it can be explained that, at the second moment mentioned above, the electric vehicle 10 typically first adjusts the stiffness, damping, and height of the suspension 70, and then outputs the first torque T1, second torque T2, third torque T3, and fourth torque T4, etc., according to the stiffness, damping, and height of the suspension 70, which can quickly alleviate the nose-up phenomenon of the electric vehicle 10 during start-up. The stiffness adjustment of the suspension 70 and the torque output of the drive motor 20 are mutually coordinated and interrelated in the control of this nose-up mitigation method, and do not exist in isolation.

[0099] Meanwhile, the pre-adjustment of the stiffness and damping of the suspension 70 by the electric vehicle 10 can also output different adjustment values ​​in combination with different driving modes. For example, in sport mode, the pre-adjustment of the stiffness and damping of the suspension 70 is greater, while in comfort mode, the pre-adjustment of the stiffness and damping of the suspension 70 is appropriately larger, so that the driving experience of the electric vehicle 10 is more comfortable in comfort mode and more sporty in sport mode.

[0100] Based on the same concept, this application provides another method for mitigating lift-off during electric vehicle start-up. This method is used to control the output torque of the drive motor 20 of the electric vehicle 10 based on the travel of the accelerator pedal 80 and the brake pedal 90 when starting from a neutral, stationary position. This lift-off method includes the following steps:

[0101] First, at the sixth moment t6, the brake pedal 90 travel is zero and the electric vehicle 10 is engaged in forward gear, controlling the drive motor 20 to output the fifth torque T5. Second, at the seventh moment t7 after the sixth moment t6, the accelerator pedal 80 travel is greater than the second preset accelerator pedal travel, controlling the drive motor 20 to output the sixth torque T6 to drive the wheel 40 to rotate. The sixth torque T6 is greater than the fifth torque T5.

[0102] In one embodiment, when the electric vehicle 10 is in motion, the driver gradually decelerates the vehicle to a stop by braking with the brake pedal 90. The electric vehicle 10 is then in neutral, or it is started from a stationary position and remains stationary with the gear in neutral. The drive motor 20 is not used to propel the electric vehicle 10 forward. The electric vehicle 10 is in a neutral, stationary state, typically while waiting at a traffic light or after starting from a stationary position. After this, when the electric vehicle 10 prepares to accelerate forward, the brake pedal 90 has no travel, the braking device 91 does not output braking force, and the driver gradually depresses the accelerator pedal 80 to accelerate. The rotary transformer of the drive motor 20 will also experience positive acceleration.

[0103] As shown in Figure 9, when the electric vehicle 10 starts moving forward from a stationary position in neutral, firstly, at the sixth time t6, the travel of the brake pedal 90 of the electric vehicle 10 is zero and the electric vehicle 10 is in drive gear D. The electric vehicle 10 controls the drive motor 20 to output the fifth torque T5. The fifth torque T5 cannot drive the electric vehicle 10 to start moving forward on its own. Secondly, at the seventh time t7 after the sixth time t6, the travel S7 of the accelerator pedal 80 of the electric vehicle 10 is greater than the second preset accelerator pedal travel S71. The electric vehicle 10 controls the drive motor 20 to output the sixth torque T6 to drive the wheels 40 to rotate. The sixth torque T6 is greater than the fifth torque T5. The sixth torque, T6, is the driving torque, which is set according to specific factors such as vehicle weight, load, and road conditions. The sixth torque, T6, is greater than the fifth torque, T5. It should be noted that before the seventh moment, t7, the torque output by the drive motor 20 cannot independently drive the electric vehicle 10 to start and move forward. S71 is a small travel value, such as 3% of the full travel of the accelerator pedal. The moments t6, t7, torques T5, T6, and accelerator pedal travel S71 are not fixed values ​​used for all models, but are matched and calibrated to set the values ​​of each vehicle according to the specific vehicle conditions.

[0104] Regarding the above embodiments, it should be noted that the above embodiments are described under the condition of human driving. If it is in the case of autonomous driving, the brake pedal travel, accelerator pedal travel, etc. mentioned in the above embodiments may be electronic travel signals rather than specific displacement travel signals. Other related quantities may also have similar situations, but this is the same as the inventive concept of this application, only the form of expression is different.

[0105] Based on the above embodiments, when the electric vehicle 10 is in a neutral stationary state, it is controlled to start according to the above control method. Before the accelerator pedal 80 is pressed, the drive motor 20 applies a fifth torque T5 to the electric vehicle 10 when the vehicle is engaged in forward gear. Between t6 and t7, the torque output by the drive motor 20 is used as the starting preparation torque. This allows the output torque of the drive motor 20 to increase from the preparation torque when the accelerator pedal 80 is pressed, reducing the rate of change of the output torque and thus slowing down the rate of change of the vehicle's starting acceleration. This effectively suppresses the nose-up phenomenon during starting in this state.

[0106] The method for mitigating the head-up during start-up of the electric vehicle 10 further includes controlling the torque output of the drive motor 20 to be equal to the fifth torque T5 or the torque output of the drive motor to be greater than the fifth torque T5 and less than the sixth torque T6 at any time between the sixth time t6 and the seventh time t7.

[0107] In one embodiment, as shown in FIG9, the electric vehicle 10 needs to control the torque output of the drive motor 20 before the driver presses the accelerator pedal 80. Before the driver presses the accelerator pedal 80, at any time between the sixth time t6 and the seventh time t7, the electric vehicle 10 controls the drive motor 20 to make its output torque equal to the fifth torque T5. That is, between the second time t2 and the third time t3, the drive motor 20 is controlled to maintain the output torque of T5 unchanged.

[0108] In one embodiment, as shown in FIG10, the electric vehicle 10 needs to control the torque output of the drive motor 20 before the driver presses the accelerator pedal 80. Before the driver presses the accelerator pedal 80, at any time between the second time t6 and the third time t7, the electric vehicle 10 controls the drive motor 20 to make its output torque greater than the fifth torque T5 and less than the sixth torque T6. That is, between the sixth time t6 and the seventh time t7, the torque output of the drive motor 20 is maintained between the fifth torque T5 and the sixth torque T6. FIG10 is an example of one of the conditions.

[0109] Based on the above embodiments, when the electric vehicle 10 applies torque to itself using the drive motor 20 as a starting preparation torque before the accelerator pedal 80 is depressed, the applied starting preparation torque can be controlled according to actual design requirements. If the applied preparation torque is maintained at the fifth torque T5, the frequency of changes in the starting preparation torque can be reduced, making the output starting preparation torque more precise and better meeting the torque change requirements after the accelerator pedal 80 is depressed, thus better suppressing the starting lift phenomenon. If the applied torque is maintained within an appropriate torque range between the fifth torque T5 and the sixth torque T6, the precision control of the motor torque can be appropriately reduced. This can also be achieved on motor controllers with general control precision, which is more conducive to the rapid implementation of the control method, thereby better improving the practicality of mitigating the starting lift phenomenon of the electric vehicle.

[0110] In one embodiment, as shown in Figure 11, based on the same concept, at the eighth moment after the seventh moment t7, the acceleration stroke S4 of the accelerator pedal 80 increases at a rate greater than the first accelerator pedal stroke rate Sv1, that is, the electric vehicle 10 is in a state of increasing starting acceleration. At this time, the electric vehicle 10 controls the drive motor 20 to output the seventh torque T7. The seventh torque T7 is not equal to the output torque indicated by the accelerator pedal 80. In order to reduce acceleration, the seventh torque T7 is controlled to be less than the output torque T70 indicated by the accelerator pedal 80 at the fourth moment t4.

[0111] Based on the above specific embodiments, when the electric vehicle 10 applies driving torque to the electric vehicle 10 by the drive motor 20 after the accelerator pedal 80 is pressed to start, the torque output by the drive motor 20 is controlled to be appropriately less than the output torque indicated by the accelerator pedal 80 at the same time by judging the rate of increase of the acceleration stroke of the accelerator pedal 80. By reducing the torque output by the drive motor 20 while taking into account both power and comfort, the starting acceleration of the electric vehicle 10 can be controlled within a comfortable range, further controlling the starting acceleration of the electric vehicle 10, thereby accelerating and reducing the starting lift phenomenon of the electric vehicle 10.

[0112] In one embodiment, as shown in Figure 11, after the eighth time t8, the electric vehicle 10 continues to accelerate from a standstill. The rate of increase in the acceleration travel of the accelerator pedal 80 is greater than the first accelerator pedal travel rate Sv1, at which point the acceleration of the electric vehicle 10 increases. At the ninth time t9, after the eighth time t8, when the acceleration of the electric vehicle 10 equals the first preset acceleration a1, it indicates that the electric vehicle 10 has accelerated quite aggressively, and the electric vehicle 10 needs to limit its drive torque output. At this time, the drive motor 20 is controlled to output the eighth torque T8, which is less than the output torque indicated by the accelerator pedal 80 at the eighth time t8. After the ninth time t9, the acceleration of the electric vehicle 10 is greater than the first preset acceleration a1, and the driver continues to depress the accelerator pedal 80, increasing the acceleration travel of the accelerator pedal 80. At this point, the electric vehicle 10 cannot further increase its torque output, so the drive motor 20 is controlled to maintain the output of the eighth torque T8 unchanged until the driver reduces the travel of the accelerator pedal 80 to a comfortable driving range.

[0113] Based on the above specific embodiments, after the electric vehicle 10 presses the accelerator pedal 80 to start, the torque output of the drive motor 20 of the electric vehicle 10 is controlled by the start-up lift-up control method, so as to limit the acceleration of the electric vehicle 10 within the acceleration range required for comfortable driving, thereby preventing the electric vehicle 10 from over-accelerating and making the start-up lift-up phenomenon of the electric vehicle 10 quickly and effectively controlled.

[0114] The method for mitigating head lift during start-up of the electric vehicle 10 further includes: when the electric vehicle 10 is traveling uphill, controlling the fifth torque T5 output by the drive motor 20 to be proportional to the gradient of the uphill road; when the electric vehicle 10 is traveling downhill, controlling the fifth torque T5 output by the drive motor 20 to be inversely proportional to the gradient of the downhill road.

[0115] Based on the same concept, the method for mitigating the lift-off during start-up of the electric vehicle 10 can further include: when the electric vehicle 10 is traveling uphill, controlling the sixth torque T6 output by the drive motor 20 and the subsequent torque for the electric vehicle to start forward are proportional to the slope of the uphill road; when the electric vehicle 10 is traveling downhill, controlling the sixth torque T6 output by the drive motor 20 and the subsequent torque for the electric vehicle to start forward are inversely proportional to the slope of the downhill road. In one embodiment, when the electric vehicle 10 is starting uphill, due to the drag of the weight component of the electric vehicle 10, the electric vehicle 10 can appropriately increase the output torque during lift-off control to obtain the same driving experience as when starting on a flat road. As shown in Figure 12, when the electric vehicle 10 is traveling uphill, the fifth torque T5, the sixth torque T6 output by the drive motor 20, and the subsequent torque for the electric vehicle to start moving forward are proportional to the slope of the uphill road. They increase appropriately as the slope increases to overcome the drag effect of gravity on the slope. Therefore, the aforementioned torques are appropriately increased to T51, T61, and T71. As shown in Figure 13, when the electric vehicle 10 is traveling downhill, the fifth torque T5, the sixth torque T6 output by the drive motor 20, and the subsequent torque for the electric vehicle to start moving forward are inversely proportional to the slope of the downhill road. They decrease appropriately as the slope increases to reduce the acceleration effect of gravity on the slope. Therefore, the aforementioned torques are appropriately reduced to T52, T62, and T72.

[0116] Based on the specific embodiments described above, when the electric vehicle 10 performs start-up lift-off control, it is related to the slope of the road. The output torque is appropriately increased on uphill roads and appropriately decreased on downhill roads. This can better match the start-up lift-off control in uphill and downhill road scenarios, control the start-up lift-off in uphill and downhill road scenarios more quickly, and obtain the same driving experience as when starting on a flat road. This makes the control method of the electric vehicle more practical in various application scenarios.

[0117] The method for mitigating head-up during start-up of the electric vehicle 10 further includes controlling the fifth torque T5 and the sixth torque T6 output by the drive motor 20 when the electric vehicle 10 starts on a low-friction surface to be proportional to the adhesion coefficient of the low-friction surface.

[0118] Based on the same concept, the method for mitigating the head-up during start-up of the electric vehicle 10 may also include: when the electric vehicle 10 starts on a low-adhesion surface, the torque of the electric vehicle 10 moving forward after the seventh time t7 is proportional to the adhesion coefficient of the low-adhesion surface.

[0119] In one embodiment, when the electric vehicle 10 is on a low-friction surface such as an icy or slippery surface, the grip of the electric vehicle 10 will decrease due to the reduced coefficient of adhesion. Therefore, it is necessary to control the output torque of the electric vehicle 10 during start-up and lift-off control. Similarly, as shown in Figure 13, when the electric vehicle 10 is traveling on a low-friction surface, the fifth torque T5 and the sixth torque T6 output by the drive motor 20, as well as the torque for the electric vehicle 10 to start moving forward after the seventh moment t7, are proportional to the coefficient of adhesion of the low-friction surface. They are appropriately reduced as the coefficient of adhesion decreases to prevent the electric vehicle 10 from accelerating too quickly and causing the wheels 40 to slip. Therefore, the above torques are exemplarily reduced to T52, T62, and T72 respectively.

[0120] Based on the above embodiments, when the electric vehicle 10 is driving on a low-friction surface such as an icy or slippery surface, the output torque of the drive motor 20 is limited. As the road surface adhesion coefficient decreases, the output torque is appropriately reduced, which can better match the start-up and lift-up control in low-friction road scenarios, prevent the electric vehicle 10 from slipping when starting and lifting up on a low-friction surface, and make the start-up and lift-up control method safer.

[0121] Based on the same concept, the electric vehicle 10 can also control the suspension controller 60 at the sixth moment t6 to increase the stiffness or damping of the suspension 70 of the electric vehicle 10, or the electric vehicle 10 can control the suspension controller 60 at the sixth moment t6 to lower the height of the suspension 70 of the electric vehicle, which can further promote the body and chassis of the electric vehicle 10 to maintain a rigid connection, thereby reducing the inconsistent movement of the body and chassis during acceleration and slowing down the vehicle's start-up pitch.

[0122] Based on the same concept, all the aforementioned start-up and head-up deceleration control methods for electric vehicles 10 can also be applied to the reverse start-up condition, which will not be elaborated here.

Claims

1. A method for mitigating nose-up during electric vehicle start-up, characterized in that, The start-up lift-off mitigation method is used to control the output torque of the drive motor of the electric vehicle based on the travel of the accelerator pedal and brake pedal when the electric vehicle starts from a forward gear and is idling. The start-up lift-off mitigation method includes: When the brake pedal travel is greater than the first preset brake pedal travel at the first moment, the drive motor is controlled to output idle torque. At a second moment after the first moment, the brake pedal travel is reduced to less than a second preset brake pedal travel, and the drive motor is controlled to output a first torque, which is greater than the idle torque. After the brake pedal is fully released at the third moment following the second moment, the travel of the accelerator pedal is greater than the first preset accelerator pedal travel. The drive motor is then controlled to output a second torque to drive the wheels of the electric vehicle to rotate. The second torque is greater than the first torque.

2. The method for mitigating nose-up during start-up according to claim 1, characterized in that, The method for mitigating head-up during startup further includes: At any time between the second time and the third time, the torque output by the drive motor is controlled to be equal to the first torque.

3. The method for mitigating nose-up during start-up according to claim 1, characterized in that, The method for mitigating head-up during startup further includes: At any time between the second time point and the third time point, the torque output by the drive motor is controlled to be greater than the first torque and less than the second torque.

4. The method for mitigating nose-up during start-up according to claim 3, characterized in that, The method for mitigating head-up during startup further includes: Between the second and third time points, the torque output by the drive motor is controlled to be inversely proportional to the travel of the brake pedal.

5. The method for mitigating nose-up during start-up according to any one of claims 1-4, characterized in that, The start-up lift-off mitigation method further includes: at a fourth time after the third time, the acceleration travel rate of the accelerator pedal is greater than the first accelerator pedal travel rate, and the drive motor is controlled to output a third torque, which is less than the output torque indicated by the accelerator pedal at the fourth time.

6. The method for mitigating nose-up during start-up according to claim 5, characterized in that, The method for mitigating head-up during startup further includes: When the electric vehicle is driving uphill, the third torque output by the drive motor is proportional to the gradient of the uphill road. When the electric vehicle is traveling downhill, the third torque output by the drive motor is inversely proportional to the slope of the downhill road.

7. The method for mitigating nose-up during start-up according to claim 5 or 6, characterized in that, The start-up lift mitigation method further includes the following when the electric vehicle starts on a low-friction surface: The third torque output by the drive motor is proportional to the adhesion coefficient of the low-adhesion road surface.

8. The method for mitigating nose-up during start-up according to any one of claims 5-7, characterized in that, The method for mitigating nose-up during startup also includes: After the fourth moment, the acceleration travel rate of the accelerator pedal is greater than the first accelerator pedal travel rate. At the fifth moment after the fourth moment, the acceleration of the electric vehicle is equal to the first preset acceleration. The drive motor is controlled to output a fourth torque, which is less than the output torque indicated by the accelerator pedal at the fourth moment. After the fifth moment, the acceleration of the electric vehicle is greater than the first preset acceleration, the acceleration travel of the accelerator pedal increases, and the drive motor is controlled to maintain the output of the fourth torque.

9. The method for mitigating nose-up during start-up according to claims 1-8, characterized in that, The start-up lift-off mitigation method is used to adjust the suspension of the electric vehicle when the electric vehicle is starting in a forward gear. The start-up lift-off mitigation method further includes: At the second moment, the suspension controller of the electric vehicle increases the suspension stiffness or damping of the electric vehicle.

10. The method for mitigating nose-up during start-up according to claim 9, characterized in that, The method for mitigating nose-up during startup also includes: At the second moment, the suspension controller is controlled to lower the suspension height of the electric vehicle.

11. A method for mitigating nose-up during electric vehicle start-up, characterized in that, The start-up lift-off mitigation method is used to control the output torque of the drive motor of the electric vehicle based on the travel of the accelerator pedal and brake pedal when the electric vehicle starts from a stationary position in neutral. The start-up lift-off mitigation method includes: At the sixth moment, when the brake pedal travel is zero and the electric vehicle is in drive, the drive motor is controlled to output a fifth torque; at the seventh moment after the sixth moment, when the accelerator pedal travel is greater than the second preset accelerator pedal travel, the drive motor is controlled to output a sixth torque to drive the wheels of the electric vehicle to rotate, and the sixth torque is greater than the fifth torque.

12. The method for mitigating nose-up during start-up according to claim 11, characterized in that, The method for mitigating head-up during startup further includes: At any time between the sixth time and the seventh time, the torque output by the drive motor is controlled to be equal to the fifth torque, or the torque output by the drive motor is controlled to be greater than the fifth torque and less than the sixth torque.

13. The method for mitigating nose-up during start-up according to claim 11 or 12, characterized in that, The method for mitigating head-up during startup further includes: When the electric vehicle is driving uphill, the fifth torque output by the drive motor is proportional to the gradient of the uphill road. When the electric vehicle is traveling downhill, the fifth torque output by the drive motor is inversely proportional to the slope of the downhill road.

14. The method for mitigating head-up during start-up according to any one of claims 11-13, characterized in that, The start-up lift mitigation method further includes the following when the electric vehicle starts on a low-friction surface: The fifth torque and the sixth torque output by the drive motor are both proportional to the adhesion coefficient of the low-adhesion road surface.

15. A controller, characterized in that, The controller is used to control the electric vehicle to start forward according to the start-up lift-off relief method according to any one of claims 1-14. The controller is also used to receive DC power from the power battery of the electric vehicle and convert it into AC power to drive the drive motor of the electric vehicle to rotate.

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