New energy vehicle and vehicle speed limitation control method thereof

Abstract

The invention discloses a new energy vehicle and a vehicle speed limitation control method thereof. The method comprises the steps that a current state signal of the vehicle is obtained; according to the current state signal, determining an activation state of enabling vehicle speed limitation; when the enabling vehicle speed limit is activated, an accelerator pedal opening signal and an acceleration signal of the vehicle and the output torque of a motor are obtained; according to the vehicle speed signal, the accelerator pedal opening degree signal, the acceleration signal and the output torque of the motor, combined with the performance parameters of the vehicle, the whole vehicle demand torque is determined, and the whole vehicle demand torque is sent to the motor so that the motor can output the whole vehicle demand torque, and the vehicle speed can be limited; when the enabling vehicle speed limit is not activated, an accelerator pedal opening signal and a vehicle speed signal are obtained; and according to the vehicle speed signal and the accelerator pedal opening signal, the required torque is determined and sent to the motor, the motor outputs the required torque, and vehicle speed limitation is achieved. By means of the method, precise control over vehicle speed limitation is achieved, and the performance of the new energy vehicle is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy vehicles, and in particular to a new energy vehicle and a method for controlling a speed limit thereof. Background Art

[0002] The country's planning of new energy technology routes has promoted the rapid development of vehicle electrification, and users are gradually accepting this alternative to traditional cars driven by policies. In the development and use of such new energy vehicles, the speed limit of the vehicle has always been the focus of attention of customers and manufacturers. During the vehicle speed limit process, new energy vehicles perform dynamic torque control to prevent the speed from exceeding the speed limit. In this process, the adjustment of the motor torque plays a vital role. Therefore, how to adjust the motor torque to ensure appropriate torque and prevent the vehicle speed from exceeding the speed limit due to excessive motor torque, thereby causing the vehicle speed limit function to fail, has become a key problem.

[0003] The existing control method for automobile speed limit is usually that when the vehicle speed reaches the preset maximum speed setting value, if the motor output torque is 0 and the speed is still increasing, exceeding the preset value, the system determines that the vehicle is in a downhill condition. At this time, the vehicle controller outputs a negative torque command to put the motor in an energy recovery state, forcing the motor speed to decrease, thereby reducing the speed to within the preset maximum speed range. However, this method requires the additional introduction of an energy recovery mechanism, and the logic is complex. In addition, the vehicle controller only outputs a negative torque command when the vehicle is in a downhill condition, but does not involve the logic of determining the specific value of the negative torque when the negative torque command is output. Summary of the invention

[0004] The present invention provides a new energy vehicle and a control method for its speed limit, so as to determine whether to activate the enabled speed limit according to a vehicle speed signal and a target vehicle speed signal, and to set a corresponding calculation method when the enabled speed limit is in an activated state and an inactivated state, thereby realizing accurate calculation of the motor output torque, having simple logic, and ultimately realizing precise control of the vehicle speed limit, thereby improving the performance of the new energy vehicle and the driving experience of the user.

[0005] In a first aspect, the present invention provides a method for controlling a speed limit of a new energy vehicle, comprising:

[0006] Obtaining a current state signal of the vehicle; the current state signal includes a vehicle speed signal and a target vehicle speed signal;

[0007] determining an activation state of enabling vehicle speed limitation according to the current state signal;

[0008] When the vehicle speed limit is enabled, the accelerator pedal opening signal, acceleration signal and output torque of the motor are obtained;

[0009] According to the vehicle speed signal, the accelerator pedal opening signal, the acceleration signal and the output torque of the motor, combined with the performance parameters of the vehicle, the required torque of the vehicle is determined, and the required torque of the vehicle is sent to the motor so that the motor outputs the required torque of the vehicle to achieve speed limit control;

[0010] When the vehicle speed limit is enabled and not activated, an accelerator pedal opening signal and a vehicle speed signal are obtained;

[0011] The required torque is determined based on the vehicle speed signal and the accelerator pedal opening signal, and the required torque is sent to the motor so that the motor outputs the required torque to achieve vehicle speed limit control.

[0012] Optionally, determining the activation state of enabling the vehicle speed limit according to the current state signal includes:

[0013] When the difference between the vehicle speed signal and the target vehicle speed signal is less than a preset vehicle speed threshold, determining that the enabled vehicle speed limit is in an activated state;

[0014] When the difference between the vehicle speed signal and the target vehicle speed signal is greater than or equal to a preset vehicle speed threshold, it is determined that the enabled vehicle speed limit is in an inactive state.

[0015] Optionally, performance parameters include final drive ratio, gearbox ratio, tire radius and vehicle mass;

[0016] According to the vehicle speed signal, accelerator pedal opening signal, acceleration signal and motor output torque, combined with the vehicle's performance parameters, the vehicle's required torque is determined, including:

[0017] Determine the required torque according to the vehicle speed signal and the accelerator pedal opening signal;

[0018] Determine the total wheel end driving force based on the output torque, final drive ratio, gearbox ratio and tire radius;

[0019] Determine the vehicle's driving resistance based on the total wheel-end driving force, acceleration signal and vehicle mass;

[0020] Determine the target acceleration of the vehicle according to the vehicle speed signal and the target vehicle speed signal;

[0021] Determine the upper limit of the wheel-end driving force based on the vehicle's driving resistance, target acceleration and vehicle mass;

[0022] Determine the upper limit of the vehicle's driving force torque based on the upper limit of the wheel-end driving force, tire radius, final reduction ratio and gearbox ratio;

[0023] The vehicle required torque is determined based on the required torque and the upper limit of the vehicle driving force torque.

[0024] Optionally, the required torque is determined according to the vehicle speed signal and the accelerator pedal opening signal, including:

[0025] According to the vehicle speed signal and the accelerator pedal opening signal, the required torque is determined based on a first corresponding relationship; the first corresponding relationship is a preset corresponding relationship between the vehicle speed signal, the accelerator pedal opening signal and the required torque.

[0026] Optionally, the total wheel-end driving force is determined based on the output torque, final drive ratio, gearbox ratio and tire radius, including:

[0027] Determine the total wheel end driving force based on the first calculation formula according to the output torque, the final reduction ratio, the gearbox ratio and the tire radius;

[0028] The first calculation formula is: total wheel end driving force = (output torque * main reduction ratio * transmission speed ratio) / tire radius.

[0029] Optionally, the vehicle driving resistance is determined based on the total wheel end driving force, the acceleration signal and the vehicle mass, including:

[0030] Determine the vehicle driving resistance based on the second calculation formula according to the total wheel end driving force, the acceleration signal and the vehicle mass;

[0031] The second calculation formula is: vehicle driving resistance = total wheel end driving force – acceleration signal * vehicle mass.

[0032] Optionally, the upper limit of the wheel-end driving force is determined according to the vehicle's driving resistance, target acceleration and vehicle mass, including:

[0033] According to the vehicle running resistance, target acceleration and vehicle mass, based on the third calculation formula, the upper limit value of the wheel end driving force is determined;

[0034] The third calculation formula is: wheel end driving force upper limit = vehicle driving resistance + target acceleration * vehicle mass.

[0035] Optionally, the upper limit value of the vehicle driving force torque is determined according to the upper limit value of the wheel end driving force, the tire radius, the main reduction ratio and the gearbox ratio, including:

[0036] According to the wheel end driving force upper limit value, tire radius, final reduction ratio and gearbox speed ratio, based on the fourth calculation formula, the vehicle driving force torque upper limit value is determined;

[0037] The fourth calculation formula is: vehicle driving force torque upper limit value = (wheel end driving force upper limit value * tire radius) / (main reduction ratio * gearbox speed ratio).

[0038] Optionally, the vehicle required torque is determined according to the required torque and the upper limit value of the vehicle driving force torque, including:

[0039] The minimum value between the required torque and the upper limit value of the vehicle driving force torque is determined as the vehicle required torque.

[0040] In a second aspect, the present invention provides a new energy vehicle, including a vehicle controller and a motor; the vehicle controller is used to execute the above-mentioned control method for speed limit of the new energy vehicle.

[0041] The technical solution of the present invention obtains a current state signal of a car; the current state signal includes a vehicle speed signal and a target vehicle speed signal; according to the current state signal, the activation state of enabling the vehicle speed limit is determined; when the enabling vehicle speed limit is activated, the throttle pedal opening signal, the acceleration signal and the output torque of the motor of the car are obtained; according to the vehicle speed signal, the throttle pedal opening signal, the acceleration signal and the output torque of the motor, in combination with the performance parameters of the car, the required torque of the whole vehicle is determined, and the required torque of the whole vehicle is sent to the motor so that the motor outputs the required torque of the whole vehicle to achieve speed limit control; when the enabling vehicle speed limit is not activated, the throttle pedal opening signal and the vehicle speed signal are obtained; according to the vehicle speed signal and the throttle pedal opening signal, the required torque is determined, and the required torque is sent to the motor so that the motor outputs the required torque to achieve speed limit control. Using the above method, whether to activate the enabled speed limit is determined according to the vehicle speed signal and the target speed signal, and a calculation method is set correspondingly when the enabled speed limit is in the activated state and the inactivated state, thereby achieving accurate calculation of the motor output torque. The logic is simple, and ultimately precise control of the speed limit is achieved, thereby improving the performance of new energy vehicles and the driving experience of users.

[0042] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0044] Figure 1 A flow chart of a method for controlling speed limit of a new energy vehicle provided by an embodiment of the present invention;

[0045] Figure 2 This is a flow chart of a second method for controlling speed limit of a new energy vehicle provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0046] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0047] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0048] In one embodiment, Figure 1 This is a flow chart of a method for controlling the speed limit of a new energy vehicle provided by an embodiment of the present invention. This embodiment can be applied to the situation where the required torque of the motor is determined according to the current state of the vehicle when going downhill, so as to achieve precise control of the speed limit, and can be applied to new energy vehicles. Figure 1 As shown, the method includes:

[0049] S110: Acquire a current state signal of the vehicle.

[0050] The current state signal includes a vehicle speed signal and a target vehicle speed signal; the vehicle speed signal may be obtained by, but is not limited to, obtaining it through a vehicle speed sensor. The target vehicle speed signal is the vehicle speed limit, which is also the maximum vehicle speed, and the obtaining method may include, but is not limited to, obtaining it through a vehicle speed sensor.

[0051] S120: Determine an activation state of enabling vehicle speed limit according to the current state signal.

[0052] Specifically, after obtaining the vehicle speed signal and the target vehicle speed signal, the activation state of the enabled vehicle speed limit can be determined according to the relationship between the difference between the vehicle speed signal and the target vehicle speed signal and the preset vehicle speed threshold, that is, whether the enabled vehicle speed limit needs to be activated. Among them, when the enabled vehicle speed limit is activated, it can indicate that the speed of the new energy vehicle is close to the maximum value of the speed limit, and the speed needs to be limited. When the enabled vehicle speed limit is not activated, it can indicate that the speed of the new energy vehicle is greatly different from the maximum value of the speed limit, and the maximum value of the speed limit cannot be reached in a short time, so there is no need to limit the speed.

[0053] S130: When the vehicle speed limit is enabled, an accelerator pedal opening signal, an acceleration signal, and an output torque of a motor of the vehicle are obtained.

[0054] Among them, the acquisition of the throttle pedal opening signal may include but is not limited to acquisition through an throttle pedal opening sensor, the acquisition of the acceleration signal may include but is not limited to acquisition through an acceleration sensor, and the acquisition of the output torque of the motor may include but is not limited to acquisition through a torque sensor.

[0055] Specifically, when it is determined that the enabled vehicle speed limit is in an activated state, an accelerator pedal opening signal, an acceleration signal, and an output torque of the motor are obtained.

[0056] S140, determining the vehicle required torque based on the vehicle speed signal, the accelerator pedal opening signal, the acceleration signal and the output torque of the motor in combination with the performance parameters of the vehicle, and sending the vehicle required torque to the motor so that the motor outputs the vehicle required torque to achieve speed limit control.

[0057] The vehicle demand torque is the torque required by the new energy vehicle during driving. In this embodiment, the vehicle demand torque is the torque required by the vehicle to ensure that the vehicle speed is limited within the maximum vehicle speed.

[0058] Specifically, after obtaining the vehicle speed signal, the accelerator pedal opening signal, the acceleration signal and the output torque of the motor, the vehicle required torque can be finally calculated based on the obtained vehicle speed signal, the accelerator pedal opening signal, the acceleration signal and the output torque of the motor, combined with the performance parameters of the vehicle, using a preset calculation formula. After calculating the vehicle required torque, the calculated vehicle required torque is sent to the motor, and after receiving the vehicle required torque, the motor will output the calculated vehicle required torque accordingly, so that the vehicle speed is limited within the maximum speed, thereby realizing the control of the vehicle speed limit.

[0059] S150: When the vehicle speed limit is enabled and is not activated, obtain an accelerator pedal opening signal and a vehicle speed signal.

[0060] Specifically, when it is determined that the enabled vehicle speed limit is in an inactive state, it is necessary to obtain the accelerator pedal opening signal and the vehicle speed signal. The method of obtaining the accelerator pedal opening signal and the vehicle speed signal can refer to the above steps and will not be repeated here.

[0061] S160: Determine the required torque according to the vehicle speed signal and the accelerator pedal opening signal, and send the required torque to the motor so that the motor outputs the required torque to achieve vehicle speed limit control.

[0062] Specifically, after obtaining the vehicle speed signal and the accelerator pedal opening signal, the driver's required torque can be determined according to the preset correspondence between the vehicle speed signal, the accelerator pedal opening signal and the required torque. At this time, the calculated driver's required torque is the torque required for the entire vehicle, and the driver's required torque is sent to the motor. After receiving the required torque, the motor will output the calculated driver's required torque accordingly, so that the vehicle speed is limited within the target speed, thereby realizing the control of the vehicle speed limit.

[0063] In addition, it should be noted that the required torque ultimately output by the motor or the required torque of the entire vehicle is essentially the same as the output torque of the motor obtained by S130, that is, the output torque will be fed back after the motor outputs the torque, and the above calculation is performed based on the fed-back output torque to update the actual output required torque or the required torque of the entire vehicle in real time, forming a closed-loop control logic to adapt to different road conditions and different environments, and to ensure the accuracy of the required torque output by the motor.

[0064] The technical solution of the embodiment of the present invention obtains the current state signal of the automobile; the current state signal includes a vehicle speed signal and a target vehicle speed signal; according to the current state signal, the activation state of enabling the vehicle speed limit is determined; when the enabling vehicle speed limit is activated, the throttle pedal opening signal, the acceleration signal and the output torque of the motor of the automobile are obtained; according to the vehicle speed signal, the throttle pedal opening signal, the acceleration signal and the output torque of the motor, combined with the performance parameters of the automobile, the vehicle required torque is determined, and the vehicle required torque is sent to the motor so that the motor outputs the vehicle required torque to achieve speed limit control; when the enabling vehicle speed limit is not activated, the throttle pedal opening signal and the vehicle speed signal are obtained; according to the vehicle speed signal and the throttle pedal opening signal, the required torque is determined, and the required torque is sent to the motor so that the motor outputs the required torque to achieve speed limit control. Using the above method, whether to activate the enabled speed limit is determined according to the vehicle speed signal and the target speed signal, and a calculation method is set correspondingly when the enabled speed limit is in the activated state and the inactivated state, thereby achieving accurate calculation of the motor output torque. The logic is simple, and ultimately precise control of the speed limit is achieved, thereby improving the performance of new energy vehicles and the driving experience of users.

[0065] Figure 2This is a flow chart of a second method for controlling the speed limit of a new energy vehicle provided by an embodiment of the present invention. This embodiment refines how to determine the activation state of enabling the speed limit in the above embodiment, and how to determine the output torque of the motor after the activation state of enabling the speed limit is determined. The contents not yet detailed in this embodiment can be referred to the above embodiment, and will not be repeated here. Figure 2 As shown, the method includes:

[0066] S210: Acquire a current state signal of the vehicle.

[0067] S211 . When the difference between the vehicle speed signal and the target vehicle speed signal is less than a preset vehicle speed threshold, determine that the vehicle speed limit is enabled and in an activated state.

[0068] S212: When the difference between the vehicle speed signal and the target vehicle speed signal is greater than or equal to a preset vehicle speed threshold, determine that the enabled vehicle speed limit is in an inactive state.

[0069] Specifically, after obtaining the vehicle speed signal and the target vehicle speed signal, determine the relationship between the difference between the vehicle speed signal and the target vehicle speed signal and the preset vehicle speed threshold. When the difference is less than the preset vehicle speed threshold, it indicates that the vehicle speed is close to the target vehicle speed at this time, and may quickly reach or even exceed the target vehicle speed threshold, causing the vehicle to lose control. Therefore, it is necessary to activate the enabled speed limit to ensure that the vehicle speed is lower than the target vehicle speed. When the difference is greater than or equal to the preset vehicle speed threshold, it indicates that the vehicle speed is greatly different from the target vehicle speed at this time, and the target vehicle speed threshold may not be reached in a short time. Therefore, it is not necessary to activate the enabled speed limit to ensure normal driving of the vehicle. Among them, the preset vehicle speed threshold can be 3km / s-5km / s, which can be determined according to actual conditions and is not limited here.

[0070] S213: When the vehicle speed limit is enabled, an accelerator pedal opening signal, an acceleration signal, and an output torque of the motor of the vehicle are obtained.

[0071] S214: Determine the required torque according to the vehicle speed signal and the accelerator pedal opening signal.

[0072] Among them, this step can be refined as follows: according to the vehicle speed signal and the accelerator pedal opening signal, based on the first corresponding relationship, determine the required torque; the first corresponding relationship is a preset corresponding relationship between the vehicle speed signal, the accelerator pedal opening signal and the required torque.

[0073] Specifically, when determining the driver's required torque, the vehicle speed signal and the accelerator pedal opening signal can be used according to a preset first correspondence, that is, a two-dimensional chart. The vehicle speed signal and the accelerator pedal opening signal are both known signals obtained in real time. After substituting the vehicle speed signal and the accelerator pedal opening signal into the first correspondence, the driver's required torque can be determined.

[0074] S215: Determine the total wheel end driving force according to the output torque, the main reduction ratio, the transmission ratio and the tire radius.

[0075] Among them, this step can be refined as follows: according to the output torque, main reduction ratio, gearbox speed ratio and tire radius, based on the first calculation formula, determine the total wheel end driving force; the first calculation formula is: total wheel end driving force = (output torque * main reduction ratio * gearbox speed ratio) / tire radius.

[0076] Among them, the performance parameters of the car include the main reduction ratio, gearbox ratio, tire radius and vehicle mass. The main reduction ratio refers to the gear ratio of the main reducer in the car drive axle, which is equal to the ratio of the rotational angular velocity of the drive shaft to the rotational angular velocity of the upper axle half shaft, and is also equal to the ratio of their rotational speeds. The function of the main reduction ratio is to reduce the speed transmitted from the drive shaft, thereby increasing the torque, which has a great impact on the power performance and fuel economy of the car. The gearbox ratio refers to the ratio of the number of teeth of the main shaft gear and the countershaft gear under different gears in the gearbox, which determines the climbing ability and driving speed of the vehicle. The tire radius refers to the distance from the center of the wheel to the ground. The total driving force at the wheel end refers to the total driving force received by the car drive wheel in the horizontal direction, which is the power source for the car to travel.

[0077] Specifically, after obtaining the output torque of the motor, the output torque, the main reduction ratio, the gearbox speed ratio and the tire radius are substituted into the first calculation formula according to the output torque and the relevant parameters of the vehicle's main reduction ratio, the gearbox speed ratio and the tire radius. The output torque, the main reduction ratio, the gearbox speed ratio and the tire radius are all known parameters, and the total driving force of the wheel end can be calculated therefrom.

[0078] S216: Determine the driving resistance of the entire vehicle according to the total wheel end driving force, the acceleration signal and the vehicle mass.

[0079] Among them, this step can be refined as follows: according to the total wheel-end driving force, the acceleration signal and the vehicle mass, based on the second calculation formula, the vehicle driving resistance is determined; the second calculation formula is: vehicle driving resistance = total wheel-end driving force - acceleration signal * vehicle mass.

[0080] Among them, the vehicle driving resistance refers to the sum of all external forces that hinder the movement of the vehicle during driving.

[0081] Specifically, after the total wheel-end driving force is calculated, the total wheel-end driving force, the acceleration signal and the vehicle mass are substituted into the second calculation formula according to the calculated total wheel-end driving force. The total wheel-end driving force, the acceleration signal and the vehicle mass are all known, thereby calculating the driving resistance of the vehicle.

[0082] S217: Determine a target acceleration of the vehicle according to the vehicle speed signal and the target vehicle speed signal.

[0083] Specifically, after obtaining the vehicle speed signal and the target vehicle speed signal, according to the correspondence between the preset vehicle speed signal, the target vehicle speed signal and the target acceleration, when the vehicle speed signal and the target vehicle speed signal are known, the corresponding target acceleration of the vehicle can be determined by looking up a table or the like.

[0084] S218: Determine the upper limit of the wheel-end driving force according to the vehicle driving resistance, the target acceleration and the vehicle mass.

[0085] Among them, this step can be further refined as follows: according to the vehicle driving resistance, target acceleration and vehicle mass, based on the third calculation formula, determine the upper limit value of the wheel-end driving force; the third calculation formula is: upper limit value of the wheel-end driving force = vehicle driving resistance + target acceleration * vehicle mass.

[0086] Among them, the upper limit of the wheel-end driving force refers to the maximum driving force that the wheel end can provide under specific conditions, such as the maximum vehicle speed or maximum climbing grade.

[0087] Specifically, after determining the vehicle's driving resistance, the vehicle's driving resistance, target acceleration and vehicle mass are substituted into the third calculation formula according to the calculated vehicle's driving resistance. When the vehicle's driving resistance, target acceleration and vehicle mass are all known, the upper limit of the wheel-end driving force can be calculated.

[0088] S219: Determine the upper limit value of the vehicle driving force torque according to the upper limit value of the wheel end driving force, the tire radius, the main reduction ratio and the gearbox speed ratio.

[0089] Among them, this step can be further refined as follows: according to the upper limit value of wheel-end driving force, tire radius, main reduction ratio and gearbox speed ratio, based on the fourth calculation formula, determine the upper limit value of the driving force torque of the whole vehicle; the fourth calculation formula is: the upper limit value of the driving force torque of the whole vehicle = (upper limit value of wheel-end driving force * tire radius) / (main reduction ratio * gearbox speed ratio).

[0090] Among them, the upper limit of the vehicle's driving force torque refers to the maximum torque value that the engine can provide to the drive wheels under specific conditions. This value is an important parameter for measuring the vehicle's power performance.

[0091] Specifically, after calculating the upper limit value of the wheel-end driving force, the upper limit value of the wheel-end driving force, the tire radius, the main reduction ratio and the gearbox speed ratio are substituted into the fourth calculation formula according to the upper limit value of the wheel-end driving force. The upper limit value of the wheel-end driving force, the tire radius, the main reduction ratio and the gearbox speed ratio are all known, thereby calculating the upper limit value of the driving force torque of the whole vehicle.

[0092] S220: Determine the vehicle required torque according to the required torque and the upper limit value of the vehicle driving force torque, and send the vehicle required torque to the motor so that the motor outputs the vehicle required torque to achieve vehicle speed limit control.

[0093] Specifically, after determining the required torque and the upper limit of the vehicle driving force torque, according to the required torque and the upper limit of the vehicle driving force torque, during the downhill process, the vehicle speed cannot exceed the target vehicle speed, which can be understood as the vehicle required torque cannot exceed the upper limit of the vehicle driving force torque, and for the driver, there is also a required torque. Therefore, in order to ensure the realization of the enabling speed limit and avoid the car from losing control, this embodiment determines the minimum value of the required torque and the upper limit of the vehicle driving force torque as the vehicle required torque. After determining the vehicle required torque, the vehicle required torque is sent to the motor, and the motor outputs the vehicle required torque accordingly to achieve the control of the speed limit.

[0094] S221. When the vehicle speed limit is enabled and is not activated, obtain an accelerator pedal opening signal and a vehicle speed signal.

[0095] S222: Determine the required torque according to the vehicle speed signal and the accelerator pedal opening signal, and send the required torque to the motor so that the motor outputs the required torque to achieve vehicle speed limit control.

[0096] The technical solution of the embodiment of the present invention determines whether it is necessary to activate the enabled speed limit by utilizing the size relationship between the difference between the vehicle speed signal and the target vehicle speed signal and the preset vehicle speed threshold; and after determining that the enabled speed limit needs to be activated, determines the upper limit value of the driving force torque of the whole vehicle by utilizing a preset calculation formula, and determines the specific required torque value of the vehicle required torque based on the upper limit value of the driving force torque of the whole vehicle and the required torque of the driver, controls the motor to output the required torque of the whole vehicle, realizes accurate calculation of the required torque of the whole vehicle, ensures that the vehicle speed will not exceed the target speed on a downhill section, realizes precise control of the speed limit, and improves the performance of new energy vehicles and the driving experience of users.

[0097] In a second aspect, the present invention provides a new energy vehicle, including a vehicle controller and a motor; the vehicle controller is used to execute the above-mentioned control method for speed limit of the new energy vehicle, and has functional modules and beneficial effects corresponding to the execution method.

[0098] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0099] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for controlling the speed limit of a new energy vehicle, characterized in that: include: Acquire a current state signal of the vehicle; the current state signal includes a vehicle speed signal and a target vehicle speed signal; determining, according to the current state signal, an activation state of enabling the vehicle speed limit; When the enabled vehicle speed limit is activated, obtaining an accelerator pedal opening signal, an acceleration signal and an output torque of a motor of the vehicle; According to the vehicle speed signal, the accelerator pedal opening signal, the acceleration signal and the output torque of the motor, combined with the performance parameters of the vehicle, the vehicle required torque is determined, and the vehicle required torque is sent to the motor so that the motor outputs the vehicle required torque to achieve speed limit control; When the enabling vehicle speed limit is not activated, acquiring the accelerator pedal opening signal and the vehicle speed signal; The required torque is determined according to the vehicle speed signal and the accelerator pedal opening signal, and the required torque is sent to the motor so that the motor outputs the required torque to achieve vehicle speed limit control.

2. The control method according to claim 1, characterized in that: Determining the activation state of enabling the vehicle speed limit according to the current state signal includes: When the difference between the vehicle speed signal and the target vehicle speed signal is less than a preset vehicle speed threshold, determining that the enabled vehicle speed limit is in an activated state; When the difference between the vehicle speed signal and the target vehicle speed signal is greater than or equal to the preset vehicle speed threshold, it is determined that the enabled vehicle speed limitation is in an inactive state.

3. The control method according to claim 1, characterized in that: The performance parameters include the final reduction ratio, the gearbox ratio, the tire radius and the vehicle mass; Determining the required torque of the vehicle according to the vehicle speed signal, the accelerator pedal opening signal, the acceleration signal and the output torque of the motor in combination with the performance parameters of the vehicle includes: determining the required torque according to the vehicle speed signal and the accelerator pedal opening signal; Determining a total wheel end driving force according to the output torque, the final reduction ratio, the gearbox ratio and the tire radius; Determining the vehicle running resistance according to the total wheel end driving force, the acceleration signal and the vehicle mass; Determining a target acceleration of the vehicle according to the vehicle speed signal and the target vehicle speed signal; Determining an upper limit value of wheel-end driving force according to the vehicle running resistance, the target acceleration and the vehicle mass; Determining the upper limit value of the vehicle driving force torque according to the upper limit value of the wheel end driving force, the tire radius, the main reduction ratio and the gearbox speed ratio; The vehicle required torque is determined according to the required torque and the upper limit value of the vehicle driving force torque.

4. The control method according to claim 3, characterized in that: Determining the required torque according to the vehicle speed signal and the accelerator pedal opening signal includes: The required torque is determined according to the vehicle speed signal and the accelerator pedal opening signal based on a first corresponding relationship; the first corresponding relationship is a preset corresponding relationship between the vehicle speed signal, the accelerator pedal opening signal and the required torque.

5. The control method according to claim 3, characterized in that: Determining the total wheel end driving force according to the output torque, the final reduction ratio, the gearbox speed ratio and the tire radius includes: Determining the total wheel end driving force based on a first calculation formula according to the output torque, the final reduction ratio, the gearbox speed ratio and the tire radius; The first calculation formula is: the total wheel end driving force=(the output torque*the main reduction ratio*the gearbox speed ratio) / the tire radius.

6. The control method according to claim 3, characterized in that: Determining the vehicle driving resistance according to the wheel end total driving force, the acceleration signal and the vehicle mass includes: Determining the vehicle running resistance based on a second calculation formula according to the total wheel end driving force, the acceleration signal and the vehicle mass; The second calculation formula is: the whole vehicle running resistance=the total wheel end driving force−the acceleration signal*the whole vehicle mass.

7. The control method according to claim 3, characterized in that: Determining the upper limit of the wheel end driving force according to the vehicle running resistance, the target acceleration and the vehicle mass includes: Determining the upper limit value of the wheel end driving force based on a third calculation formula according to the vehicle running resistance, the target acceleration and the vehicle mass; The third calculation formula is: the wheel end driving force upper limit value = the vehicle running resistance + the target acceleration * the vehicle mass.

8. The control method according to claim 3, characterized in that: Determining the upper limit value of the vehicle driving force torque according to the wheel end driving force upper limit value, the tire radius, the main reduction ratio and the gearbox speed ratio includes: Determine the upper limit value of the vehicle driving force torque based on a fourth calculation formula according to the upper limit value of the wheel end driving force, the tire radius, the final reduction ratio and the gearbox speed ratio; The fourth calculation formula is: the upper limit of the vehicle driving force torque = (the upper limit of the wheel end driving force * the tire radius) / (the main reduction ratio * the gearbox speed ratio).

9. The control method according to claim 3, characterized in that: Determining the vehicle required torque according to the required torque and the upper limit value of the vehicle driving force torque includes: The minimum value between the required torque and the upper limit value of the entire vehicle driving force torque is determined as the entire vehicle required torque.

10. A new energy vehicle, characterized in that: It comprises a vehicle controller and a motor; the vehicle controller is used to execute the control method for speed limit of a new energy vehicle as described in any one of claims 1-9.

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