Vehicle energy recovery control method, device, readable storage medium and electronic device

Abstract

A vehicle energy recovery control method, device, readable storage medium and electronic device, the method comprising: estimating the load conditions of the front and rear axles according to the current mass of the whole vehicle; determining the maximum allowable motor recovery torque value of the vehicle according to the load conditions of the front and rear axles and the driver's expected deceleration; and dynamically adjusting the vehicle's coasting energy recovery torque and braking energy recovery torque within the maximum allowable motor recovery torque range, so as to achieve more energy recovery at high loads and better driving comfort at low loads, thereby achieving the same driving experience under different loads.

Description

Technical Field

[0001] The present invention relates to the field of automobiles, and in particular to a vehicle energy recovery control method, device, readable storage medium and electronic equipment. Background Art

[0002] With the country's call for energy conservation and emission reduction, and the implementation of increasingly stringent emission standards, in order to meet future market demand, more and more OEMs have launched new energy models such as pure electric and hybrid to the market. New energy vehicles have been widely used in various models, such as commercial vehicles have also added electric control in recent years.

[0003] Commercial vehicles are designed and technically used to transport people and goods. Due to cost and technical considerations, most manufacturers do not install vehicle load sensors, which cannot obtain accurate axle loads. Due to the inability to obtain accurate axle loads, the current energy recovery strategy for commercial vehicles is conservative.

[0004] To avoid the problem of vehicle loss of control caused by excessive braking energy recovery torque leading to drive wheel locking, commercial vehicles currently mainly use ESP or ABS equipped on the vehicle to avoid wheel locking, but the activation of ESP or ABS will cause a sudden change in recovery torque, affecting the driving experience of the vehicle. In addition, for vehicles with large loading mass, there are disadvantages such as small braking torque, long braking distance, high energy consumption and too little recovery energy. Summary of the invention

[0005] In view of the above situation, it is necessary to provide a vehicle energy recovery control method, device, readable storage medium and electronic device to dynamically adjust the vehicle's coasting energy recovery torque and braking energy recovery torque to make the vehicle safe, economical and efficient.

[0006] A vehicle energy recovery control method, comprising:

[0007] Obtaining the current mass of the vehicle, and determining the static load of the drive shaft of the vehicle according to the current mass;

[0008] Acquiring an expected deceleration set by a driver, and correcting the static load of the drive shaft according to the expected deceleration to obtain a dynamic load of the drive shaft;

[0009] Calculating the maximum resistance torque acting on the wheel when the driving wheel is locked according to the dynamic load of the driving shaft;

[0010] Calculating the braking torque required for deceleration of the vehicle according to the current mass and the expected deceleration;

[0011] When it is detected that the current energy recovery type of the whole vehicle is the coasting energy recovery type, the whole vehicle is controlled to be motor braked, and the torque of the motor brake is the smallest one among the braking torque, the maximum resistance torque and the maximum motor braking torque;

[0012] When it is detected that the current energy recovery type of the whole vehicle is the braking energy recovery type, the whole vehicle is controlled to be motor braking and mechanical braking, and the torque of motor braking and mechanical braking is determined according to the braking torque, the maximum resistance torque and the maximum motor braking torque.

[0013] Furthermore, in the above-mentioned vehicle energy recovery control method, the step of determining the torque of the motor braking and the mechanical braking according to the braking torque, the maximum resistance torque and the maximum motor braking torque comprises:

[0014] When the braking torque is less than the maximum resistance torque and less than or equal to the maximum motor braking torque, determining that the motor braking torque is equal to the maximum resistance torque and the mechanical braking torque is zero;

[0015] When the braking torque is less than the maximum resistance torque and greater than the maximum motor braking torque, it is determined that the motor braking torque is equal to the maximum motor braking torque, and the mechanical braking torque is the braking torque minus the maximum motor braking torque;

[0016] When the braking torque is greater than or equal to the maximum resistance torque, and the maximum resistance torque is less than or equal to the maximum motor braking torque, determining that the motor braking torque is equal to the maximum resistance torque, and the mechanical braking torque is zero;

[0017] When the braking torque is greater than or equal to the maximum resistance torque, and the maximum resistance torque is greater than the maximum motor braking torque, it is determined that the motor braking torque is equal to the maximum motor braking torque, and the mechanical braking torque is the maximum resistance torque minus the maximum motor braking torque.

[0018] Furthermore, in the above vehicle energy recovery control method, the step of obtaining the current mass of the whole vehicle comprises:

[0019] During a driving cycle of the vehicle, a sampling sample is taken at a certain interval, and two time points at a preset time interval are taken in each sampling sample;

[0020] Determine the driving equations at two time points within the sample to calculate the mass of the whole vehicle respectively, and calculate the mass of the whole vehicle of the sample according to the driving equations at the two time points;

[0021] The current mass of the whole vehicle is determined according to the whole vehicle mass of each of the samples.

[0022] Furthermore, in the above-mentioned vehicle energy recovery control method, the formula for calculating the vehicle mass of the sampled sample according to the driving equation at the two time points is:

[0023]

[0024]

[0025] Wherein, P0 and P1 are the instantaneous driving power of the vehicle at the two time points, η0 and η1 are the transmission efficiency of the driving system at the two time points, V0 and V1 are the instantaneous speed of the vehicle at the two time points, M is the total mass of the vehicle, and f r0 and f r1 are the rolling resistance coefficients at the two time points, θ0 and θ1 are the road slopes at the two time points, ρ a is the air density, C D is the air resistance coefficient, A f is the frontal area of ​​the vehicle, σ is the conversion factor of the vehicle's rotating mass, a0 and a1 are the instantaneous accelerations at the two time points respectively;

[0026] At the two time points, the transmission efficiency of the vehicle power system, the tire rolling resistance coefficient and the road slope are considered unchanged, and the following equations are used to obtain:

[0027]

[0028] because, The vehicle mass M of the sample is obtained,

[0029]

[0030] Furthermore, in the above-mentioned vehicle energy recovery control method, the step of determining the static load of the drive shaft of the whole vehicle according to the current mass comprises:

[0031] The static load of the drive shaft is queried in a static axle load reference model according to the current mass, and the static axle load reference model includes loads of the front axle and the rear axle under different vehicle masses.

[0032] Furthermore, in the above-mentioned vehicle energy recovery control method, the formula for correcting the static load of the drive shaft according to the expected deceleration is:

[0033]

[0034] Among them, W G′ is the dynamic load of the drive shaft, WG is the static load of the drive shaft, M T is the current mass of the vehicle, a is the expected deceleration, H0 is the height of the center of mass of the vehicle, and L0 is the wheelbase of the vehicle.

[0035] Furthermore, in the above vehicle energy recovery control method, the step of detecting the current energy recovery type of the whole vehicle comprises:

[0036] According to the throttle opening signal and the brake pedal opening signal, determine whether the energy recovery condition is currently met;

[0037] When it is identified that the current accelerator pedal is at 0 and the brake pedal is not depressed, it is determined that the energy recovery condition is currently met and the current energy recovery type of the vehicle is the coasting energy recovery type;

[0038] When the current accelerator pedal is 0 and the brake pedal opening is greater than a certain value, it is determined that the energy recovery condition is currently met and the current energy recovery type is brake energy recovery.

[0039] The present invention also discloses a vehicle energy recovery control device, comprising:

[0040] The acquisition module is used to obtain the current mass of the vehicle;

[0041] A static load determination module, used to determine the static load of the drive shaft of the vehicle according to the current mass;

[0042] a correction module, used for obtaining an expected deceleration set by a driver, and correcting the static load of the drive shaft according to the expected deceleration to obtain a dynamic load of the drive shaft;

[0043] A maximum resistance torque calculation module, used to calculate the maximum resistance torque acting on the wheel when the driving wheel is locked according to the dynamic load of the driving shaft;

[0044] A braking torque calculation module, used to calculate the braking torque required for deceleration of the entire vehicle according to the current mass and the expected deceleration;

[0045] A first control module is used for controlling the whole vehicle to perform motor braking when it is detected that the current energy recovery type of the whole vehicle is a coasting energy recovery type, and the torque of the motor braking is the smallest one among the braking torque, the maximum resistance torque and the maximum motor braking torque;

[0046] The second control module is used to control the whole vehicle to perform motor braking and mechanical braking when it is detected that the current energy recovery type of the whole vehicle is the braking energy recovery type, and determine the torque of the motor braking and mechanical braking according to the braking torque, the maximum resistance torque and the maximum motor braking torque.

[0047] The present invention also discloses an electronic device, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements any one of the above-mentioned methods when executing the computer program.

[0048] The present invention also discloses a computer-readable storage medium on which a program is stored. When the program is executed by a processor, any one of the above-mentioned methods is implemented.

[0049] Under the premise that the driving wheels do not lock, the present invention takes the driver's expected deceleration as the target deceleration of the whole vehicle, dynamically adjusts the coasting recovery torque and the brake energy recovery torque, and optimizes the power consumption of the whole vehicle while ensuring the braking force and driving smoothness of the whole vehicle, so that the vehicle reaches a safe, economical and efficient state. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 A flow chart of a vehicle energy recovery control method provided by a first embodiment of the present invention;

[0051] Figure 2 It is the relationship diagram between brake opening and brake torque;

[0052] Figure 3 is a flow chart of a method for calculating the current mass of a vehicle in a second embodiment of the present invention;

[0053] Figure 4 It is a schematic diagram of the multi-point sampling method;

[0054] Figure 5 is a schematic diagram of a vehicle energy recovery control system in a third embodiment of the present invention;

[0055] Figure 6 A control flow chart of a vehicle energy recovery control system in a third embodiment of the present invention;

[0056] Figure 7 A structural block diagram of a vehicle energy recovery control device in a fourth embodiment of the present invention

[0057] Figure 8 Schematic diagram of the structure of an electronic device in an embodiment of the present invention. DETAILED DESCRIPTION

[0058] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0059] These and other aspects of the embodiments of the present invention will become clear with reference to the following description and drawings. In these descriptions and drawings, some specific implementations of the embodiments of the present invention are specifically disclosed to represent some ways of implementing the principles of the embodiments of the present invention, but it should be understood that the scope of the embodiments of the present invention is not limited thereto. On the contrary, the embodiments of the present invention include all changes, modifications and equivalents that fall within the spirit and connotation of the appended claims.

[0060] See also Figure 1 , which is a vehicle energy recovery control method in the first embodiment of the present invention, includes steps S11 to S16.

[0061] Step S11, obtaining the current mass of the entire vehicle, and determining the static load of the drive shaft of the entire vehicle according to the current mass.

[0062] The current mass of the vehicle is the current total mass of the vehicle, including the curb mass and the loaded mass. The static load of the drive shaft of the vehicle is determined based on the current mass. In specific implementation, the static load of the drive shaft can be queried in the static axle load reference model according to the current mass. The static axle load reference model includes the loads on the front and rear axles of the vehicle under different vehicle masses. The driving modes of automobiles can be roughly divided into: front-wheel drive, rear-wheel drive and four-wheel drive, and most of the cars that people buy on a daily basis are front-wheel drive and rear-wheel drive. For front-wheel drive vehicles, the drive shaft is the front axle, and the static load of the front axle needs to be queried. For rear-wheel drive vehicles, the drive shaft is the rear axle, and the static load of the rear axle needs to be queried.

[0063] The static axle load distribution reference model is a static axle load reference model of the front and rear axles under different vehicle weights obtained by using the test method described in GB / T 12674-1990 "Measurement Method for Automobile Mass (Weight) Parameters". For a target vehicle with two axles, such as a light passenger car, light truck or pickup truck, the axle load reference model is shown in Table 1:

[0064] Table 1 Axle load reference model

[0065]

[0066] In the above table, M0 represents the vehicle curb weight, which can be equivalent to the vehicle unloaded weight; ΔM is the vehicle weight change gradient between any two adjacent sampling points during the test process, S1, S2, S3...S n is the sampling point, n is the number of sampling points, and the value of n will affect the accuracy of the axle load reference model; S n The total vehicle mass M0+(n-1)ΔM at the sampling point should be greater than or equal to the fully loaded mass of the vehicle (it is best to consider a certain overload); They are the static loads of the front and rear axles obtained by testing at the corresponding sampling points.

[0067] Step S12, obtaining the expected deceleration set by the driver, and correcting the static load of the drive shaft according to the expected deceleration to obtain the dynamic load of the drive shaft.

[0068] According to the axle load distribution reference model, the static loads of the front and rear axles under the current vehicle mass are obtained. At the same time, the transfer of axle load distribution caused by dynamic driving is considered (the change of acceleration causes the change of front and rear axle loads), and finally the loads of the vehicle drive axle are calculated separately, such as the dynamic load of the front axle W f and rear axle dynamic load W r .

[0069] It can be understood that the axle load distribution reference model in Table 1 does not involve the entire mass of the vehicle. Therefore, the calculated current vehicle mass M T Should meet:

[0070] M0≤M T ≤M0+(n-1)ΔM.

[0071] For example, when the vehicle mass M T When in the range [M0, M0+ΔM], there are: front axle load satisfy Rear axle load satisfy

[0072] It can be understood that when the current mass of the vehicle is between the total mass of the vehicle at two adjacent sampling points, considering a certain overload, the total mass of the vehicle at the latter sampling point is generally taken as the current mass of the vehicle.

[0073] Assuming that the vehicle is a rigid model and is traveling on a flat road, the influence of the road slope on the load is not considered (designed according to the maximum climbing gradient of 30%, the actual angle is 16.42°, cos16.42°≈0.959, which has little effect on the final calculation result). Here, only the axle load change caused by the acceleration change of the whole vehicle is considered. In the process of sliding or braking torque return (acceleration a<0), the formula for correcting the static load of the drive shaft according to the expected deceleration is:

[0074]

[0075] Among them, W G′ is the dynamic load of the drive shaft, W G is the static load of the drive shaft, M T is the current mass of the vehicle, a is the expected deceleration, H0 is the height of the center of mass of the vehicle, and L0 is the wheelbase of the vehicle.

[0076] The drive shaft is driven by the front axle or the rear axle, and the corresponding dynamic load distribution of the front and rear axles is as follows:

[0077] The dynamic load on the front axle can be expressed as:

[0078]

[0079] The dynamic load on the rear axle can be expressed as:

[0080]

[0081] Step S13, calculating the maximum resistance torque acting on the wheel when the driving wheel is locked according to the dynamic load of the driving shaft.

[0082] To avoid tire locking, the maximum limit value of the equivalent resistance torque allowed to act on the tire under the expected deceleration is calculated as follows:

[0083] (1) For a front-wheel drive vehicle, its maximum resistance torque is T f Should be:

[0084]

[0085] (2) For a rear-wheel drive vehicle, its maximum resistance torque is T r Should be:

[0086]

[0087] Where r is the tire rolling radius, which is the design value; μ is the road adhesion coefficient; a is the vehicle acceleration, m / s 2 ; H0 is the center of mass height, which is the design value; L0 is the vehicle wheelbase, which is the design value.

[0088] Step S14, calculating the braking torque required for decelerating the vehicle according to the current mass and the expected deceleration.

[0089] According to the vehicle driving equation, we have:

[0090]

[0091] Right now,

[0092]

[0093] Where a is the target deceleration, T c0 is the braking torque that needs to be applied to the drive wheel to decelerate the vehicle, M is the current mass of the vehicle, and g is the acceleration of gravity. During the sliding recovery process, the braking torque of the vehicle is the motor braking torque acting on the wheel end; during the braking deceleration process, the braking torque of the vehicle is the sum of the mechanical braking torque and the electric braking torque acting on the wheel end.

[0094] Step S15, when it is detected that the current energy recovery type of the whole vehicle is the coasting energy recovery type, the whole vehicle is controlled to be motor braked, and the torque of the motor brake is the smallest one among the braking torque, the maximum resistance torque and the maximum motor braking torque.

[0095] In specific implementation, first, it is necessary to determine whether the energy recovery condition is currently met through the throttle opening signal or the brake pedal opening signal;

[0096] When it is identified that the current accelerator pedal is at 0 and the brake pedal is not depressed, it is determined that the energy recovery condition is currently met and the current energy recovery type of the vehicle is the coasting energy recovery type;

[0097] When the current accelerator pedal is 0 and the brake pedal opening is greater than a certain value, it is determined that the energy recovery condition is currently met and the current energy recovery type is brake energy recovery.

[0098] When it is detected that the current energy recovery type of the vehicle is the coasting energy recovery type, the vehicle is controlled to be motor-braked, and the coasting energy recovery torque (i.e., the torque of the motor braking) is calculated. Specifically, the vehicle performs coasting energy recovery at the target deceleration a and the drive wheels do not lock, which should meet the following conditions:

[0099] Maximum allowable coasting energy recovery torque T for front-wheel drive vehicles m ,

[0100] T m =min{T f , T c0 , T max};

[0101] Maximum allowable coasting energy recovery torque T for rear-wheel drive vehicles n ,

[0102] T n =min{T r , T c0 , T max}.

[0103] That is, in the case of coasting energy recovery, the motor braking torque should not exceed the maximum resistance torque and the maximum torque T of the motor. max .

[0104] The above T c0 、T f and T r It is greatly affected by the mass of the vehicle. Within the capacity of the motor, the greater the mass of the vehicle, the greater the torque allowed for coasting recovery. Therefore, compared with an unloaded vehicle, a larger coasting energy recovery torque can be applied to a fully loaded vehicle.

[0105] Step S16, when it is detected that the current energy recovery type of the whole vehicle is the braking energy recovery type, the whole vehicle is controlled to be motor braking and mechanical braking, and the torque of motor braking and mechanical braking is determined according to the braking torque, the maximum resistance torque and the maximum motor braking torque.

[0106] When it is detected that the current energy recovery type of the vehicle is the braking energy recovery type, the vehicle is controlled to perform motor braking and mechanical braking at the same time. During the braking process of the vehicle and without the drive wheel locking, the following conditions shall be met:

[0107] For front-wheel drive vehicles, the mechanical brake torque T brk and the motor braking torque T rec The sum of T c The maximum resistance torque T acting on the wheel f The relationship can be expressed as:

[0108] T rec +T brk =T c ≤T f ;

[0109] For rear-wheel drive vehicles, the mechanical brake torque T brk and the motor braking torque T rec The sum of T c The maximum resistance torque T acting on the wheel r The relationship can be expressed as:

[0110] T rec +T brk =T c ≤T r ;

[0111] Where, T rec The maximum torque value allowed by the motor to recover according to the control strategy should not be greater than the maximum torque capacity of the motor T max , T brk is the torque of the mechanical brake.

[0112] Therefore, under the braking energy recovery type, according to the relationship between the calculated braking torque, the maximum resistance torque and the maximum motor braking torque, the braking of the vehicle has the following four situations:

[0113] 1. When the braking torque is less than the maximum resistance torque and less than or equal to the maximum motor braking torque, it is determined that the motor braking torque is equal to the maximum resistance torque and the mechanical braking torque is zero;

[0114] Second, when the braking torque is less than the maximum resistance torque and greater than the maximum motor braking torque, it is determined that the motor braking torque is equal to the maximum motor braking torque, and the mechanical braking torque is the braking torque minus the maximum motor braking torque;

[0115] 3. When the braking torque is greater than or equal to the maximum resistance torque, and the maximum resistance torque is less than or equal to the maximum motor braking torque, it is determined that the motor braking torque is equal to the maximum resistance torque, and the mechanical braking torque is zero;

[0116] Fourth, when the braking torque is greater than or equal to the maximum resistance torque, and the maximum resistance torque is greater than the maximum motor braking torque, it is determined that the motor braking torque is equal to the maximum motor braking torque, and the mechanical braking torque is the maximum resistance torque minus the maximum motor braking torque.

[0117] When the braking torque required for vehicle deceleration is less than the maximum resistance torque, the braking torque can be fully met by motor braking or mechanical braking. Figure 2 It can be seen that when the brake pedal opening (or target deceleration) is small (corresponding to segment ABC), the braking torque requirement T c0 ≤T max When the braking torque is all motor braking torque, that is, T c0 =T rec ; When the brake pedal opening (or target deceleration) is large (corresponding to the CDE segment), the braking torque requirement T c0 ≥T max When the mechanical brake is needed for auxiliary braking, the torque of the mechanical brake is T brk =T c0 -T max .

[0118] When the braking torque required for vehicle deceleration is greater than or equal to the maximum resistance torque, in order to avoid tire locking, the actual torque of the vehicle cannot exceed the maximum resistance torque. Therefore, the actual torque of the vehicle should be the maximum resistance torque. For the front-wheel drive vehicle T C =T f , for rear-wheel drive vehicles T C =T r . And, when the maximum resistance torque is less than or equal to the maximum motor braking torque, the vehicle deceleration is entirely achieved by motor braking, and the motor braking torque is equal to the maximum resistance torque. When the maximum resistance torque is greater than the maximum motor braking torque, it is determined that the motor braking torque is equal to the maximum motor braking torque, and the mechanical braking torque is the maximum resistance torque minus the maximum motor braking torque.

[0119] This embodiment estimates the load of the vehicle drive shaft based on the vehicle mass combined with the axle load distribution reference model. On the premise that the drive wheel does not lock, the driver's expected deceleration is used as the target deceleration of the vehicle (the deceleration during the coasting energy recovery process can be adjusted by the driver through the energy recovery level as needed, and the deceleration during the braking process can be adjusted by the driver through the brake pedal), and the coasting recovery torque and the braking energy recovery torque are dynamically adjusted to optimize the vehicle power consumption while ensuring the vehicle's braking force and driving smoothness, so that the vehicle reaches a safe, economical and efficient state.

[0120] Commercial vehicles are cars that are designed and technically used to transport people and goods. The total mass of the vehicle is determined by the curb mass and the loading mass. The loading mass has a great impact on the total mass of the vehicle. For example, a certain brand of light truck has a curb mass of 3 tons and a maximum allowable total mass of 4.5 tons. Considering the actual loading conditions, the total mass of the vehicle may be even greater. For medium and heavy trucks, the allowable loading mass is even greater, which has a greater impact on the total mass of the vehicle. The current industry generally lacks effective methods to calculate the real-time total mass of the vehicle. Based on this, Figure 3 As shown, the second embodiment of the present invention further discloses a method for calculating the current mass of a vehicle, including steps S21 to S23.

[0121] Step S21, within a driving cycle of the vehicle, a sampling sample is taken at a certain interval, and two time points with a preset time interval are taken in each sampling sample.

[0122] Step S22, respectively determining the driving equations for calculating the mass of the whole vehicle at two time points within the sampling sample, and calculating the mass of the whole vehicle of the sampling sample according to the driving equations at the two time points.

[0123] Step S23, determining the current mass of the whole vehicle according to the mass of the whole vehicle of each sample.

[0124] In any continuous driving cycle, there are any two adjacent time points t0 and t1, and their time interval nT0 (for example, n=5, the sampling period is T0=10ms). According to the driving equation of the car It can be seen that:

[0125] The driving equation at time t0 can be expressed as follows:

[0126]

[0127] The driving equation at time t1 can be expressed as follows:

[0128]

[0129] In the formula,

[0130] P0 and P1 are the instantaneous driving power of the vehicle at time t0 and time t1, respectively, kw;

[0131] η0 and η1 are the transmission efficiencies of the drive system at time t0 and time t1 respectively, which can be expressed as η = η m *η n *η p Calculated, where: η m is the motor working efficiency; η n is the transmission shaft efficiency; η p The working efficiency of the gearbox or reduction box;

[0132] V0, V1 are the instantaneous vehicle speeds at time t0 and time t1, m / s;

[0133] M is the total mass of the vehicle, kg;

[0134] f r0 and f r1 are the rolling resistance coefficients at time t0 and time t1 respectively;

[0135] θ0 and θ1 are the road slopes at time t0 and t1 respectively;

[0136] ρ a is the air density, kg / m 3 ;

[0137] C D is the air resistance coefficient;

[0138] A f is the frontal area of ​​the vehicle, m 2 ;

[0139] σ is the conversion factor of the vehicle's rotating mass, which can be obtained from Calculated. ∑I w is the moment of inertia of all wheels, I f is the flywheel moment of inertia, i g is the transmission ratio of a certain gear of the gearbox, i0 is the transmission ratio of the main reducer, η is the total transmission efficiency of the transmission system, M is the total mass of the car, r is the rolling radius of the tire, for a given vehicle or system, ∑I w ,I f 、i g , i0, η and r are all fixed known values.

[0140] a0 and a1 are the instantaneous accelerations of the vehicle at time t0 and t1 respectively, which can be calculated from the speed change values ​​of any two consecutive cycles, that is, m / s 2;

[0141] T0 is the calculation sampling period, ms.

[0142] Since the time interval nT0 is extremely short, it can be approximately assumed that at time t0 and time t1, the transmission efficiency of the vehicle power system, the tire rolling resistance coefficient and the road slope remain unchanged. Therefore, it can be obtained from equations (1) and (2):

[0143]

[0144] That is, the calculation expression of the vehicle mass of the sampling sample is as follows:

[0145]

[0146] The vehicle mass calculation is allowed within the same driving cycle (the total mass of the vehicle is approximately assumed to be constant during driving) and when the vehicle speed meets certain conditions (the vehicle is in a driving state and the vehicle acceleration is within the boundary range). The multi-point sampling method can be adopted, that is, a sampling sample is taken at a fixed time interval, and two points with a time interval of nT0 are taken in each sampling sample, and the vehicle mass of the sample point is calculated according to the above method.

[0147] Figure 4 The figure shows a schematic diagram of the multi-point sampling method. The specific usage is: points A, B, C, D... are different samples, and the time interval between two adjacent sampling samples is T. The total number of sampling samples is N, and the quality calculated for each sampling sample is M A 、M B 、M C 、M D …M P 、M Q ….

[0148] There are many mathematical methods that can be used to process the sample data, such as recursive least squares method, etc. Here, the most easily understood average method is used to process the data obtained by the multi-point sampling method, and the corrected vehicle mass is:

[0149]

[0150] The use of different mathematical calculation methods, as well as the values ​​of the interval time nT0 and the number of sampling samples N, will affect the calculation accuracy of the vehicle mass.

[0151] According to the above method, the mass of the vehicle can be accurately calculated, and then the prepared axle load can be calculated, and the energy recovery torque can be calculated based on the mass of the vehicle and the axle load.

[0152] See also Figure 5, shown is a schematic diagram of a vehicle energy recovery control system in the third embodiment of the present invention, which is composed of an input unit, a vehicle control unit and an execution unit. The input unit is mainly responsible for the acquisition and processing of initial signals, such as vehicle speed signals, vehicle drive power signals, brake pedal opening signals, energy recovery level signals, etc. The vehicle control unit is mainly responsible for vehicle mass calculation, static axle load calculation, driver expected torque identification, dynamic axle load calculation, drive wheel locking torque boundary calculation and energy recovery torque calculation, and finally outputs the requested motor recovery torque value; the execution unit refers to the motor responsible for recovering torque.

[0153] Figure 6 The control flow based on the vehicle energy recovery control system is shown. The specific control process is as follows:

[0154] Step S301, judging whether the current state of the vehicle satisfies the mass calculation, if yes, proceed to step S302. When the vehicle speed is greater than a certain value and the vehicle driving torque is greater than a certain value, the vehicle mass calculation is allowed, and the process proceeds to step S302.

[0155] Step S302, calculating the vehicle mass according to the vehicle power and vehicle speed signal. Specifically, the vehicle mass can be calculated according to the vehicle mass calculation method in the second embodiment.

[0156] Step S303, estimating the static loads of the front and rear axles based on the calculated vehicle mass and referring to the load distribution model.

[0157] S304, judging whether the energy recovery condition is currently met through the throttle opening signal or the brake pedal opening signal. When the vehicle control unit recognizes that the current throttle pedal is 0 and the brake pedal is not pressed, it is judged that coasting energy recovery is allowed; when the vehicle control unit recognizes that the current throttle pedal is 0 and the brake pedal opening is greater than a certain value, it is judged that braking energy recovery is allowed.

[0158] Step S305, looking up a table to obtain the driver's expected deceleration according to the coasting energy recovery level set by the driver or the brake pedal opening degree pressed.

[0159] (1) Identification of the driver's expected deceleration during taxiing

[0160] Table 2 Driver's expected deceleration during taxiing

[0161] Coasting energy recovery level Level 1 Level 2 Level3 ... <![CDATA[Expected deceleration (m / s 2 )]]> <![CDATA[a L1 ]]> <![CDATA[a L2 ]]> <![CDATA[a L3 ]]> ...

[0162] (2) Identification of the driver's expected deceleration during braking

[0163] Table 3 Driver's expected deceleration during braking process

[0164] Brake pedal opening (%) 5 10 20 ... 100 <![CDATA[Expected deceleration (m / s 2 )]]> <![CDATA[a 05 ]]> <![CDATA[a 10 ]]> <![CDATA[a 20 ]]> ... a100

[0165] The above Table 2 and Table 3 can be determined by calibration during vehicle commissioning.

[0166] Step S306, correcting the front and rear axle loads according to the driver's expected acceleration, and calculating the front and rear axle dynamic loads.

[0167] Step S307, calculating the maximum resistance torque when the driving wheels are locked according to the dynamic loads of the front and rear axles.

[0168] Step S308, calculating the coasting energy recovery torque and the braking energy recovery torque.

[0169] By calculating the mass of the entire vehicle and comparing it with the reference model of the vehicle load distribution, the load conditions of the front and rear axles are estimated; then, based on the load conditions of the front and rear axles and the driver's expected deceleration, the vehicle's maximum allowable motor recovery torque value is determined; and within the maximum allowable motor recovery torque range, the vehicle's coasting energy recovery torque and braking energy recovery torque are dynamically adjusted to achieve more energy recovery at high loads and better driving comfort at low loads, thereby achieving the same driving experience under different loads.

[0170] In order to illustrate the technical effect of the present invention, the vehicle energy recovery control method of the present invention is applied to a pure electric rear-wheel drive project of a certain brand of light truck.

[0171] The vehicle-related design parameters are described in Table 4:

[0172] Table 4 Vehicle related parameters

[0173]

[0174] Corresponding to no-load and full-load states, the relevant parameters are shown in Table 5:

[0175] Table 5 Load distribution related parameters

[0176]

[0177] According to the above parameters, the following parameters are obtained through analysis and calculation:

[0178] Table 6 Driving wheel locking limit torque

[0179]

[0180] According to the vehicle driving equation, considering that the vehicle is running at a constant deceleration during the coasting recovery process, the motor braking torque acting on the wheel end at the target deceleration is calculated as shown in Table 7:

[0181] Table 7 Motor braking torque at target coasting deceleration

[0182]

[0183] Taking the torque locking boundary calculated in Table 6 as the constraint condition, the motor braking torque described in Table 7 needs to be corrected.

[0184] The above embodiment shows that: taking the coasting recovery target deceleration of 0.1g as an example, at a speed of 80kph, the motor recovery torque allowed when unloaded is 750Nm, and the motor recovery torque allowed when fully loaded is 1965Nm. Therefore, the intelligent energy recovery solution based on vehicle mass calculation can realize dynamic adjustment of the motor braking torque, improve the recovery efficiency; at the same time, ensure that the vehicle has good drivability.

[0185] See also Figure 7 , is a vehicle energy recovery control device in a fourth embodiment of the present invention, comprising:

[0186] An acquisition module 41 is used to acquire the current mass of the vehicle;

[0187] A static load determination module 42, configured to determine the static load of the drive shaft of the vehicle according to the current mass;

[0188] A correction module 43 is used to obtain an expected deceleration set by a driver, and to correct the static load of the drive shaft according to the expected deceleration to obtain a dynamic load of the drive shaft;

[0189] A maximum resistance torque calculation module 44, used to calculate the maximum resistance torque acting on the wheel when the driving wheel is locked according to the dynamic load of the driving shaft;

[0190] A braking torque calculation module 45, configured to calculate the braking torque required for deceleration of the vehicle according to the current mass and the expected deceleration;

[0191] A first control module 46 is used for controlling the vehicle to perform motor braking when it is detected that the current energy recovery type of the vehicle is a coasting energy recovery type, and the torque of the motor braking is the smallest one among the braking torque, the maximum resistance torque and the maximum motor braking torque;

[0192] The second control module 47 is used to control the whole vehicle to perform motor braking and mechanical braking when it is detected that the current energy recovery type of the whole vehicle is the braking energy recovery type, and determine the torque of the motor braking and mechanical braking according to the braking torque, the maximum resistance torque and the maximum motor braking torque.

[0193] The vehicle energy recovery control device provided in the embodiment of the present invention has the same implementation principle and technical effects as those of the aforementioned method embodiment. For the sake of brief description, for matters not mentioned in the device embodiment, reference may be made to the corresponding contents in the aforementioned method embodiment.

[0194] Another aspect of the present invention provides an electronic device, see Figure 8 , shown is an electronic device in the fourth embodiment of the present invention, including a processor 10, a memory 20, and a computer program 30 stored in the memory and executable on the processor, and when the processor 10 executes the computer program 30, the vehicle energy recovery control method as described above is implemented.

[0195] The electronic device may be, but is not limited to, a computer device capable of playing a virtual mahjong game, such as an MCU or a computer. The processor 10 may be, in some embodiments, a central processing unit (CPU), a controller, a microcontroller, a microprocessor or other data processing chip, for running program codes stored in the memory 20 or processing data.

[0196] Among them, the memory 20 includes at least one type of readable storage medium, and the readable storage medium includes flash memory, hard disk, multimedia card, card-type memory (for example, SD or DX memory, etc.), magnetic memory, disk, optical disk, etc. The memory 20 may be an internal storage unit of an electronic device in some embodiments, such as a hard disk of the electronic device. The memory 20 may also be an external storage device of an electronic device in other embodiments, such as a plug-in hard disk equipped on the electronic device, a smart memory card (Smart Media Card, SMC), a secure digital (Secure Digital, SD) card, a flash card (FlashCard), etc. Further, the memory 20 may also include both an internal storage unit of the electronic device and an external storage device. The memory 20 may be used not only to store application software and various types of data installed in the electronic device, but also to temporarily store data that has been output or is to be output.

[0197] Optionally, the electronic device may also include a user interface, a network interface, a communication bus, etc. The user interface may include a display (Display), an input unit such as a keyboard (Keyboard), and the optional user interface may also include a standard wired interface and a wireless interface. Optionally, in some embodiments, the display may be an LED display, a liquid crystal display, a touch-sensitive liquid crystal display, and an OLED (Organic Light-Emitting Diode) touch device, etc. Among them, the display may also be appropriately referred to as a display screen or a display unit, which is used to display information processed in the electronic device and to display a visual user interface. The network interface may optionally include a standard wired interface, a wireless interface (such as a WI-FI interface), which is generally used to establish a communication connection between the device and other electronic devices. The communication bus is used to realize the connection communication between these components.

[0198] It should be pointed out that Figure 8 The structure shown does not constitute a limitation on the electronic device. In other embodiments, the electronic device may include fewer or more components than those shown in the figure, or combine certain components, or arrange the components differently.

[0199] The present invention further provides a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, the vehicle energy recovery control method as described above is implemented.

[0200] Those skilled in the art will appreciate that the logic and / or steps represented in the flowchart or otherwise described herein, for example, may be considered as an ordered list of executable instructions for implementing logical functions, and may be specifically implemented in any computer-readable medium for use by an instruction execution system or device (such as a computer-based system, a system including a processor, or other system that can obtain instructions from an instruction execution system or device and execute instructions), or in conjunction with such instruction execution systems or devices. For purposes of this specification, "computer-readable medium" may be any device that can contain, store, communicate, propagate, or transmit a program for use by an instruction execution system or device, or in conjunction with such instruction execution systems or devices.

[0201] More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic device), a portable computer disk case (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be a paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, deciphering or, if necessary, processing in another suitable manner, and then stored in a computer memory.

[0202] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, a plurality of steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or a combination thereof: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0203] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0204] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A vehicle energy recovery control method, characterized in that: include: Obtaining the current mass of the vehicle, and determining the static load of the drive shaft of the vehicle according to the current mass; Acquiring an expected deceleration set by a driver, and correcting the static load of the drive shaft according to the expected deceleration to obtain a dynamic load of the drive shaft; Calculating the maximum resistance torque acting on the wheel when the driving wheel is locked according to the dynamic load of the driving shaft; Calculating the braking torque required for deceleration of the vehicle according to the current mass and the expected deceleration; When it is detected that the current energy recovery type of the whole vehicle is the coasting energy recovery type, the whole vehicle is controlled to be motor braked, and the torque of the motor brake is the smallest one among the braking torque, the maximum resistance torque and the maximum motor braking torque; When it is detected that the current energy recovery type of the whole vehicle is the braking energy recovery type, the whole vehicle is controlled to be motor braking and mechanical braking, and the torque of the motor braking and the mechanical braking is determined according to the braking torque, the maximum resistance torque and the maximum motor braking torque; The step of obtaining the current mass of the vehicle comprises: During a driving cycle of the vehicle, a sampling sample is taken at a certain interval, and two time points at a preset time interval are taken in each sampling sample; Determine the driving equations at two time points within the sample to calculate the mass of the whole vehicle respectively, and calculate the mass of the whole vehicle of the sample according to the driving equations at the two time points; Determining the current mass of the whole vehicle according to the whole vehicle mass of each of the sampling samples; The formula for calculating the vehicle mass of the sample according to the driving equation at the two time points is: Wherein, P0 and P1 are the instantaneous driving power of the vehicle at the two time points, η0 and η1 are the transmission efficiency of the driving system at the two time points, V0 and V1 are the instantaneous speed of the vehicle at the two time points, M is the total mass of the vehicle, and f r0 and f r1 are the rolling resistance coefficients at the two time points, θ0 and θ1 are the road slopes at the two time points, ρ a is the air density, C D is the air resistance coefficient, A f is the frontal area of ​​the vehicle, σ is the conversion factor of the vehicle's rotating mass, a0 and a1 are the instantaneous accelerations at the two time points respectively; At the two time points, the transmission efficiency of the vehicle power system, the tire rolling resistance coefficient and the road slope are considered unchanged, and the following equations are used to obtain: because, The vehicle mass M of the sample is obtained, 2. The vehicle energy recovery control method according to claim 1, characterized in that: The step of determining the torque of motor braking and mechanical braking according to the braking torque, the maximum resistance torque and the maximum motor braking torque comprises: When the braking torque is less than the maximum resistance torque and less than or equal to the maximum motor braking torque, determining that the motor braking torque is equal to the maximum resistance torque and the mechanical braking torque is zero; When the braking torque is less than the maximum resistance torque and greater than the maximum motor braking torque, it is determined that the motor braking torque is equal to the maximum motor braking torque, and the mechanical braking torque is the braking torque minus the maximum motor braking torque; When the braking torque is greater than or equal to the maximum resistance torque, and the maximum resistance torque is less than or equal to the maximum motor braking torque, determining that the motor braking torque is equal to the maximum resistance torque, and the mechanical braking torque is zero; When the braking torque is greater than or equal to the maximum resistance torque, and the maximum resistance torque is greater than the maximum motor braking torque, it is determined that the motor braking torque is equal to the maximum motor braking torque, and the mechanical braking torque is the maximum resistance torque minus the maximum motor braking torque.

3. The vehicle energy recovery control method according to claim 1, characterized in that: The step of determining the static load of the drive shaft of the vehicle according to the current mass comprises: The static load of the drive shaft is queried in a static axle load reference model according to the current mass, and the static axle load reference model includes loads of the front axle and the rear axle under different vehicle masses.

4. The vehicle energy recovery control method according to claim 1, characterized in that: The formula for correcting the static load of the drive shaft according to the expected deceleration is: Among them, W G′ is the dynamic load of the drive shaft, W G is the static load of the drive shaft, M T is the current mass of the vehicle, a is the expected deceleration, H0 is the height of the center of mass of the vehicle, and L0 is the wheelbase of the vehicle.

5. The vehicle energy recovery control method according to claim 1, characterized in that: The step of detecting the current energy recovery type of the whole vehicle comprises: According to the throttle opening signal and the brake pedal opening signal, determine whether the energy recovery condition is currently met; When it is identified that the current accelerator pedal is at 0 and the brake pedal is not depressed, it is determined that the energy recovery condition is currently met and the current energy recovery type of the vehicle is the coasting energy recovery type; When the current accelerator pedal is 0 and the brake pedal opening is greater than a certain value, it is determined that the energy recovery condition is currently met and the current energy recovery type is brake energy recovery.

6. A vehicle energy recovery control device, characterized in that: include: The acquisition module is used to obtain the current mass of the vehicle; A static load determination module, used to determine the static load of the drive shaft of the vehicle according to the current mass; a correction module, used for obtaining an expected deceleration set by a driver, and correcting the static load of the drive shaft according to the expected deceleration to obtain a dynamic load of the drive shaft; A maximum resistance torque calculation module, used to calculate the maximum resistance torque acting on the wheel when the driving wheel is locked according to the dynamic load of the driving shaft; A braking torque calculation module, used to calculate the braking torque required for deceleration of the entire vehicle according to the current mass and the expected deceleration; A first control module is used for controlling the whole vehicle to perform motor braking when it is detected that the current energy recovery type of the whole vehicle is a coasting energy recovery type, and the torque of the motor braking is the smallest one among the braking torque, the maximum resistance torque and the maximum motor braking torque; A second control module is used to control the whole vehicle to perform motor braking and mechanical braking when it is detected that the current energy recovery type of the whole vehicle is a braking energy recovery type, and determine the torque of the motor braking and the mechanical braking according to the braking torque, the maximum resistance torque and the maximum motor braking torque; The step of obtaining the current mass of the vehicle comprises: During a driving cycle of the vehicle, a sampling sample is taken at a certain interval, and two time points at a preset time interval are taken in each sampling sample; Determine the driving equations at two time points within the sample to calculate the mass of the whole vehicle respectively, and calculate the mass of the whole vehicle of the sample according to the driving equations at the two time points; Determining the current mass of the whole vehicle according to the whole vehicle mass of each of the sampling samples; The formula for calculating the vehicle mass of the sample according to the driving equation at the two time points is: Wherein, P0 and P1 are the instantaneous driving power of the vehicle at the two time points, η0 and η1 are the transmission efficiency of the driving system at the two time points, V0 and V1 are the instantaneous speed of the vehicle at the two time points, M is the total mass of the vehicle, and f r0 and f r1 are the rolling resistance coefficients at the two time points, θ0 and θ1 are the road slopes at the two time points, ρ a is the air density, C D is the air resistance coefficient, A f is the frontal area of ​​the vehicle, σ is the conversion factor of the vehicle's rotating mass, a0 and a1 are the instantaneous accelerations at the two time points respectively; At the two time points, the transmission efficiency of the vehicle power system, the tire rolling resistance coefficient and the road slope are considered unchanged, and the following equations are used to obtain: because, The vehicle mass M of the sample is obtained, 7. An electronic device, characterized in that: include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the method according to any one of claims 1 to 5 when executing the computer program.

8. A computer-readable storage medium having a program stored thereon, characterized in that: When the program is executed by a processor, the method according to any one of claims 1 to 5 is implemented.

Images