Vehicle torque control method and system, and computer readable storage medium

Abstract

The present invention relates to a vehicle torque control method and system thereof, and a computer-readable storage medium, comprising: when a vehicle is in an idle charging condition, the engine net output torque control in the over-discharge stage and the over-charge stage of the battery is cyclically and alternately performed; wherein, in the over-discharge stage, the corresponding engine target net output torque is determined according to the over-discharge energy in the over-discharge stage, and the engine output corresponding torque is controlled according to the engine target net output torque; wherein, in the over-charge stage, the corresponding engine target net output torque is determined according to the over-charge energy in the over-charge stage, and the engine output corresponding torque is controlled according to the engine target net output torque. Through the present invention, the engine idle charging torque is determined according to the energy fluctuation in the battery balance interval, at least the problem of the large energy fluctuation accuracy range of the battery SOC is solved, thereby better realizing the battery SOC balance in the vehicle idle charging condition.

Description

Technical Field

[0001] The present invention relates to the technical field of hybrid vehicles, and in particular to a vehicle torque control method and system thereof, and a computer-readable storage medium. Background Art

[0002] At present, the schemes for idle charging of hybrid vehicles are to calibrate the control and switching of fixed idle charging in normal charging, trickle charging, over-discharge control and over-charge control from the perspective of the engine, and then adjust the idle charging stage control switching through the changes in the battery SOC; it is a post-action battery SOC balance control method, and the post-action adjustment can only be achieved after the battery SOC fluctuates.

[0003] In the process of implementing the present invention, the inventors found that the above control method has the following technical problems:

[0004] (1) The energy fluctuation accuracy range of the battery's SOC is too large;

[0005] (2) The duration of the over-discharge charge control and over-charge charge control phases and the phase switching frequency cannot be accurately controlled;

[0006] (3) The battery charging current is affected by the dynamic changes of factors such as the engine torque, powertrain and accessories, and it is impossible to accurately control the maximum value limit of the battery overcharge and over-discharge current. Summary of the invention

[0007] The purpose of the present invention is to propose a vehicle torque control method and its system, and a computer-readable storage medium, so as to determine the engine idle charging torque according to the energy fluctuation in the battery balance interval, at least to solve the problem that the energy fluctuation accuracy range of the battery SOC is too large, so as to better achieve the battery SOC balance in the vehicle idle charging condition.

[0008] To achieve the above object, the present invention provides a vehicle torque control method in a first aspect, the method comprising: when the vehicle is in an idle charging condition, cyclically and alternately performing engine net output torque control in a battery over-discharge stage and an over-charge stage;

[0009] Wherein, in the over-discharge stage, the corresponding target net output torque of the engine is determined according to the over-discharge energy in the over-discharge stage, and the engine is controlled to output the corresponding torque according to the target net output torque of the engine;

[0010] In the overcharging stage, the corresponding target net output torque of the engine is determined according to the overcharging energy in the overcharging stage, and the engine is controlled to output the corresponding torque according to the target net output torque of the engine.

[0011] Optionally, the overdischarge energy of the previous overdischarge stage is 1+γ times the overdischarge energy of the current overdischarge stage, and the overcharge energy of the previous overcharge stage is 1+γ times the overcharge energy of the current overcharge stage; γ is a preset cycle battery overdischarge coefficient greater than 0.

[0012] Optionally, the battery overdischarge stage includes an energy overdischarge switching stage and an energy continuous overdischarge stage;

[0013] Among them, when in the energy over-discharge switching stage, according to the preset motor target electric power P PM2 Calculate the mechanical target torque of the motor at the current stage According to the Calculate the target net output torque of the engine at the current stage According to the Control the engine output corresponding torque;

[0014] When the energy is in the continuous over-discharge stage, the battery target current I of the current stage is determined according to the over-discharge energy of the over-discharge stage. CB3 According to the I CB3 Calculate the motor target electric power P at the current stage PM3 According to the P PM3 Calculate the mechanical target torque of the motor at the current stage According to the Calculate the target net output torque of the engine at the current stage According to the Control the engine output corresponding torque.

[0015] Optionally, the battery overcharging stage includes an energy overcharging switching stage and an energy continuous overcharging stage;

[0016] Among them, when in the energy overcharge switching stage, the maximum current allowed by the battery overcharge control is based on the overcharge energy in the overcharge stage and the preset calibration Determine the battery target current I in the current stage CB4 According to the I CB3 Calculate the motor target electric power P at the current stage PM4 According to the P PM4 Calculate the mechanical target torque of the motor at the current stage According to the Calculate the target net output torque of the engine at the current stage According to the Control the engine output corresponding torque;

[0017] Wherein, when in the energy continuous overcharge stage, according to the overcharge energy in the overcharge stage, the I CB3 And the ICB4 Determine the battery target current I in the current stage CB6 According to the I CB6 Calculate the motor target electric power P at the current stage PM6 According to the P PM6 Calculate the mechanical target torque of the motor at the current stage According to the Calculate the target net output torque of the engine at the current stage According to the Control the engine output corresponding torque.

[0018] Optionally, the method further comprises:

[0019] Before entering the first over-discharge stage, the net output torque of the engine is controlled during the idle trickle charging stage;

[0020] The net output torque control of the engine during the idle trickle charging stage includes:

[0021] According to the formula Calculate the battery target current I at the current stage CB1 ;in To charge the battery in the idle trickle charging stage, V CB1 is the current battery voltage, t A The length of the idle trickle charging phase;

[0022] According to the I CB1 Calculate the motor target electric power P at the current stage PM1 ;

[0023] According to the P PM1 Calculate the mechanical target torque of the motor at the current stage

[0024] According to the Calculate the target net output torque of the engine at the current stage According to the Control the engine output corresponding torque.

[0025] Optionally, the method further comprises:

[0026] When in the energy over-discharge switching stage, the battery target current I of the current stage is calculated according to the following formula: CB2 :

[0027]

[0028]

[0029] P PC2=P 附件 +P PM2

[0030] Among them, P PB2 is the battery target power during the energy over-discharge switching phase, V CB2 is the current battery voltage, P PC2 is the charge and discharge equivalent power in the energy over-discharge switching stage, P 附件 is the vehicle accessory power, I CC2 is the charge and discharge equivalent current, The maximum current allowed for battery over-discharge control is preset. is the equivalent resistance from the motor to the accessory end, is the equivalent resistance from the battery to the accessory terminal;

[0031] When the energy is in the continuous over-discharge stage, the battery target current I of the current stage is calculated and determined according to the following formula: CB3 :

[0032]

[0033] in, is the over-discharge energy in the over-discharge stage, t B is the duration of the energy over-discharge switching phase, t C The duration of the energy over-discharge stage;

[0034] The motor target electric power P at the current stage is calculated according to the following formula: PM3 :

[0035]

[0036]

[0037] Among them, P PC3 It is the charging and discharging equivalent power during the continuous over-discharge stage of energy.

[0038] Optionally, where t C The values ​​are as follows:

[0039]

[0040] in, It is the minimum value of the sum of the preset time lengths of the energy over-discharge switching phase and the energy continuous over-discharge phase.

[0041] Optionally, the method further comprises:

[0042] When in the energy overcharge switching stage, the battery target current I of the current stage is calculated and determined according to the following formula: CB4 :

[0043]

[0044] in, is the overcharge energy in the overcharge stage, V CB4 is the current battery voltage, t D+E is the duration of the overcharge phase;

[0045] The motor target electric power P at the current stage is calculated according to the following formula: PM4 :

[0046]

[0047]

[0048] Among them, P PC4 It is the charge and discharge equivalent power in the energy overcharge switching stage.

[0049] Optionally, the method further comprises:

[0050] When the energy is in the continuous overcharge stage, the battery target current I of the current stage is calculated and determined according to the following formula: CB6 :

[0051]

[0052] Among them, t D is the duration of the energy overcharge switching phase, t E The duration of the energy overcharge phase;

[0053] The motor target electric power P at the current stage is calculated according to the following formula: PM6 :

[0054]

[0055]

[0056] P PB6 =P PB4 =I CB4 ·V CB4

[0057] Among them, V CB6 is the current battery voltage.

[0058] Optionally, where t E The values ​​of are as follows:

[0059]

[0060] in, It is the minimum value of the sum of the preset durations of the energy overcharge switching phase and the energy continuous overcharge phase.

[0061] The second aspect of the present invention provides a vehicle torque control system for implementing the vehicle torque control method described in the first aspect, wherein when the vehicle is in an idle charging state, the net output torque control of the engine in the battery over-discharge stage and the over-charge stage is performed alternately in a cycle;

[0062] Wherein, the system comprises:

[0063] an over-discharge stage control unit, configured to control the net output torque of the engine in the over-discharge stage, determine a corresponding target net output torque of the engine according to the over-discharge energy in the over-discharge stage, and control the engine to output a corresponding torque according to the target net output torque of the engine; and

[0064] The overcharging stage control unit is used to control the net output torque of the engine in the overcharging stage, determine the corresponding target net output torque of the engine according to the overcharging energy in the overcharging stage, and control the engine to output the corresponding torque according to the target net output torque of the engine.

[0065] Optionally, the system further comprises:

[0066] The idle trickle charging stage control unit is used to control the net output torque of the engine in the idle trickle charging stage before entering the first over-discharge stage. According to the formula Calculate the battery target current I at the current stage CB1 According to the I CB1 Calculate the motor target electric power P at the current stage PM1 According to the P PM1 Calculate the mechanical target torque of the motor at the current stage And, according to the Calculate the target net output torque of the engine at the current stage According to the Control the engine output corresponding torque;

[0067] in, To charge the battery in the idle trickle charging stage, V CB1 is the current battery voltage, t A The length of the idle trickle charge phase.

[0068] A third aspect of the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the vehicle torque control method described in the first aspect.

[0069] In summary, the embodiments of the present invention provide a vehicle torque control method and system thereof, and a computer-readable storage medium, which have at least the following beneficial effects:

[0070] The embodiment of the present invention is applicable to a variety of hybrid configurations. It is a universal battery SOC balancing control technology. During the implementation process, when the vehicle is in an idle charging condition, the engine net output torque control in the over-discharge stage and the over-charge stage of the battery is cyclically and alternately performed; in the over-discharge stage, the corresponding engine target net output torque is determined according to the over-discharge energy in the over-discharge stage, and the engine output corresponding torque is controlled according to the engine target net output torque; in the over-charge stage, the corresponding engine target net output torque is determined according to the over-charge energy in the over-charge stage, and the engine output corresponding torque is controlled according to the engine target net output torque. Compared with the prior art which requires the battery SOC to fluctuate before realizing the after-effect adjustment, the embodiments of the present invention are designed by analyzing the battery charge and discharge power, and actively make the battery cycle between the over-discharge stage and the over-charge stage to adjust the idle charge and discharge power, and take the energy fluctuation range of the controlled target, that is, the balance interval of the battery, as the target to actively reversely deduce and determine the corresponding net output torque of the engine under the idle charging condition, thereby solving the problem in the prior art that the energy fluctuation accuracy range of the battery SOC is too large due to the after-effect adjustment, thereby better realizing the battery SOC balance under the vehicle idle charging condition.

[0071] Other features and advantages of the present invention will be set forth in the description which follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0072] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. 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 paying creative work.

[0073] Figure 1 The figure is a flow chart of a vehicle torque control method according to an embodiment of the present invention.

[0074] Figure 2 Schematic diagram of a single-motor hybrid powertrain model.

[0075] Figure 3 A schematic diagram of a dual-motor hybrid powertrain model.

[0076] Figure 4 Schematic diagram of a micro-attenuation curve of battery over-discharge and over-charge energy under multi-cycle control under idle charging conditions in one embodiment of the present invention.

[0077] Figure 5 The figure is a control principle diagram of a vehicle torque control method in one embodiment of the present invention.

[0078] Figure 6 The figure is a schematic structural diagram of a vehicle torque control system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0079] Various exemplary embodiments, features and aspects of the present disclosure will be described in detail below with reference to the accompanying drawings. In addition, in order to better illustrate the present invention, numerous specific details are given in the specific embodiments below. It should be understood by those skilled in the art that the present invention can also be implemented without certain specific details. In some examples, means well known to those skilled in the art are not described in detail in order to highlight the subject matter of the present invention.

[0080] See also Figure 1 , an embodiment of the present invention provides a vehicle torque control method, which is applicable to various hybrid configurations, such as Figure 2 The single-motor hybrid powertrain model shown, for example Figure 3 The dual-motor hybrid powertrain model shown above Figure 2 and 3 In the model, the engine torque consists of two parts. One part is the net output torque of the driving motor when the engine is idling, which is also the engine control output target required for idle charging; the other part is the various friction resistance torques generated by the engine itself when the engine is running. For hybrid power, the hybrid control unit generally only cares about the engine torque or power involved in the net power output, while the friction torque or resistance power inside the engine is controlled by the engine itself. Therefore, for the above two configurations of hybrid power in idle charging conditions, the equivalent rotational inertia participating in the idle charging condition is calculated as follows:

[0081] Equivalent moment of inertia of single motor configuration:

[0082] J SER =J e +J K0 +J m +J C (1)

[0083] Equivalent moment of inertia of dual motor configuration:

[0084] J SER =J e +J C0 +J m ·(i EM1 ) 2 +J R (2)

[0085] Among them, when the vehicle reaches the battery SOC control balance point under idle charging conditions, the hybrid power will judge and perform battery power balance control based on the battery SOC value. However, if the engine is not stopped, it is almost difficult to fully control the engine and motor to accurately provide the vehicle's accessory power under idle conditions. For this reason, the general practice for this condition is to use the battery as an energy storage device to dynamically adjust the idle charging net output power of the powertrain within the allowable energy fluctuation range to complete the battery SOC balance control. However, it needs to be adjusted according to the change of the battery SOC, which easily leads to the problem that the energy fluctuation accuracy range of the battery SOC is too large. Therefore, the method of this embodiment proposes the following technical means to solve this problem:

[0086] When the vehicle is in an idle charging condition, the engine net output torque control of the battery in the over-discharge stage and the over-charge stage is performed alternately in a cycle; wherein, in each over-discharge stage, the corresponding engine target net output torque is determined according to the over-discharge energy of the over-discharge stage, and the engine output corresponding torque is controlled according to the engine target net output torque; wherein, in each over-charge stage, the corresponding engine target net output torque is determined according to the over-charge energy of the over-charge stage, and the engine output corresponding torque is controlled according to the engine target net output torque.

[0087] It should be noted that the over-discharge stage refers to the battery being equivalent to providing electrical energy (releasing electrical energy) for the entire vehicle idling condition, and is often cited as biased discharge in the industry. The over-charge stage refers to the battery being equivalent to a load (attracting electrical energy) for the entire vehicle idling condition, and is often cited as biased charge in the industry.

[0088] Specifically, Figure 1 A simple process of n cycles is shown in the figure. The method of this embodiment is designed by analyzing the charge and discharge power of the battery, and actively allows the battery to cycle alternately between the over-discharge stage and the over-charge stage to adjust the idle charge and discharge power. The energy fluctuation range of the controlled target, that is, the balance interval of the battery, is used as the target to actively reversely deduce and determine the corresponding net output torque of the engine under the idle charging condition, and control the net output torque of the vehicle engine, thereby solving the problem of the large energy fluctuation accuracy range of the battery SOC due to the after-the-fact adjustment in the prior art, thereby better achieving the battery SOC balance under the vehicle idle charging condition.

[0089] It should be noted that the prior art has not yet provided a technical concept for controlling the net output torque of the engine in a cyclic alternating over-discharge phase and over-charge phase.

[0090] In a specific example, for multiple over-discharge stages and over-charge stages that are cyclically performed during the battery SOC balance control process, the over-discharge energy of the previous over-discharge stage is 1+γ times the over-discharge energy of the current over-discharge stage, and the over-charge energy of the previous over-charge stage is 1+γ times the over-charge energy of the current over-charge stage; γ is a preset cyclic battery over-discharge coefficient greater than 0.

[0091] Specifically, a cycle includes an over-discharge phase and an over-charge phase, that is, Figure 1 As shown in the dotted rectangular box, after completing a cycle of battery SOC balance control, since idle charging is still continuing, the energy control adjustment based on the battery SOC balance interval needs to be controlled following the previous cycle. However, in the control design of this embodiment, the cumulative effect caused by the inaccuracy of the actual battery energy at the start and end points of a cycle is taken into account, so a reset control for adjusting the accumulated energy according to the change of the actual SOC of the battery is set; the specific approach is to add battery SOC monitoring to the continuous over-discharge stage and the continuous over-charge stage of each cycle and extend the continuous over-discharge time and the continuous over-charge time according to the change of the SOC value, so that the battery over-discharge energy and the over-charge energy in multiple cycles of the battery SOC balance control generally present a micro-over-discharge state with a γ attenuation coefficient, as shown in the following figure. Figure 4 shown.

[0092] Among them, the over-discharge and over-charge time statistics under 15 cycles of idle charging SOC balance control measured in the test are shown in Table 1 below:

[0093] Table 1 - Statistics of overcharge and overdischarge time in multi-cycle SOC balance control

[0094] Cycle times Over discharge time(s) Overcharge time(s) 1 10.80 41.10 2 11.80 46.10 3 11.10 38.00 4 10.30 44.80 5 11.08 34.65 6 9.07 33.01 7 11.08 32.75 8 10.08 34.77 9 10.20 35.02 10 11.08 41.07 11 10.83 33.76 12 11.45 35.78 13 9.83 32.00 14 9.32 33.76 15 10.95 45.35

[0095] Exemplarily, in this embodiment, γ is preferably but not limited to 0.023.

[0096] For a specific example, see Figure 5 , the method further comprises:

[0097] Before entering the first over-discharge stage, the net output torque of the engine is controlled in the idle trickle charging stage, that is, the idle charging is performed until the battery SOC control balance point is reached; wherein, the idle trickle charging stage corresponds to Figure 5 Phase A in

[0098] Specifically, since the best way to charge the battery is to use constant current charging before the single cell voltage of the battery reaches the maximum allowable voltage, constant current charging is used as the control target in the idle charging trickle charging stage.

[0099] The net output torque control of the engine during the idle trickle charging stage includes:

[0100] Considering that the SOC and energy of the battery are not linear, it is necessary to calibrate the battery energy increment target of trickle charging according to the target rate of actual SOC increase. Right now In order to achieve constant current control and controllable charging rate calibration in the trickle charging stage, it is necessary to calculate the net charging current of the battery according to the energy ladder of the battery SOC change; the battery charging energy in stage A can be calculated as follows:

[0101]

[0102]

[0103] Among them, Wi is the battery SOC state during the control process, Figure 5 Where i is 1 to 8, is the battery SOC value corresponding to Wi, Indicates the battery energy value corresponding to Wi+1 minus Wi; E W is the energy value corresponding to the battery SOC of 100%; I CB1 is the battery target current in the current A phase, V CB1 is the battery voltage at this time, t A The duration of the current A phase, which is determined by the battery energy increment target of the current A phase. The correspondence is determined and there is a unique corresponding relationship between the two.

[0104] The target charging power P of the battery in the current A phase can be calculated based on the current target battery net charging current in the A phase and the minimum stability requirements of the engine power and motor power at idle speed. PB1 , Actual equivalent power of charge and discharge P PC1 、Motor target electric power P PM1 They are as follows:

[0105]

[0106] P PC1 =P 附件 +P PB1 (6)

[0107]

[0108] in, is the battery voltage corresponding to the battery SOC state at W1; The minimum current allowed by the battery, is the minimum power allowed by the engine, is the minimum power allowed by the motor, These are all preset parameter values;

[0109] Among them, P 附件 The power of vehicle accessories. Specifically, the idle charging accessory power generally includes the DC power used for charging the 12V low-voltage battery and the power used by the electric air conditioner, that is, P 附件 =P DCDC +P 空调 ;P DCDC , P 空调 is the preset parameter value;

[0110] in, is the equivalent resistance from the motor to the accessory end; I is the equivalent resistance from the battery to the accessory terminal; CC1 is the actual equivalent current of charge and discharge in the current A phase, which can be calculated based on the actual equivalent power P of charge and discharge PC1 And the equivalent resistance from the motor to the accessory end Calculated, that is

[0111] The motor mechanical target torque in the current A phase can be calculated by the motor target electric power of formula (7) and taking into account the idle speed fluctuation: and the target net engine torque as follows:

[0112]

[0113]

[0114] Among them, η m The efficiency value of the motor mechanical power converted into electrical power is preset; i EM1 is the preset speed ratio value from the engine to the motor; The motor speed value corresponding to the preset A phase, in rpm; is the preset speed fluctuation angular velocity, in rad / s;

[0115] In a specific example, the battery overdischarge stage includes an energy overdischarge switching stage and an energy continuous overdischarge stage;

[0116] Specifically, when the battery is trickle charged to the SOC control balance point, the battery energy over-discharge control is required. Since the actual SOC of the battery is not equal to the SOC allowed by the hybrid, in order to control the SOC value of the hybrid to remain stable, it is necessary to test and calibrate the over-discharge and over-charge battery energy change targets for SOC balance control in advance. Since the battery over-discharge control must be switched from the over-charge or trickle charge stage, the battery energy over-discharge control in this process is divided into two stages: energy over-discharge switching stage and energy continuous over-discharge stage, corresponding to Figure 5 Phase B and Phase C.

[0117] Among them, see Figure 5 , when in the energy over-discharge switching stage, that is Figure 5 In the B phase, according to the preset motor target electric power P PM2 Calculate the mechanical target torque of the motor at the current stage According to the Calculate the target net output torque of the engine at the current stage According to the Control the engine output corresponding torque;

[0118] Specifically, when switching to the over-discharge stage, the motor target power P can be determined by calibration. PM2 =0, the battery will be fully discharged to meet the power demand of accessories, thus the current B stage charge and discharge equivalent power P can be calculated PC2 and the battery's target power P PB2 as follows:

[0119] P PC2 =P 附件 +P PM2 (10)

[0120]

[0121] The target over-discharge current can be calculated from the battery target net over-discharge power of formula (11) and the battery voltage at this time as follows:

[0122]

[0123] Among them, I CC2 is the actual equivalent current of charge and discharge in the current B phase, which can be calculated based on the actual equivalent power P of charge and discharge PC2 And the equivalent resistance from the motor to the accessory end Calculated, that is V CB2 is the battery voltage of the current B phase; The maximum current allowed for battery over-discharge control;

[0124] In the current B phase, the electric power of the motor is controlled by calibration to be 0 kW, and the mechanical target torque of the motor in the current B phase can be calculated as follows:

[0125]

[0126] in, The motor speed value corresponding to the preset B phase, in rpm;

[0127] To correct the rapid decrease of engine idle torque to prevent flameout and improve speed stability, The speed can be increased appropriately, for example, by 25 rpm; the target net output torque of the engine can be calculated as follows:

[0128]

[0129] Among them, t B is the time length corresponding to the current B stage;

[0130] In actual control, in order to correct the oscillation caused by the change of engine mechanical power lagging behind the change of electric power, the control time of this stage needs to be within the normal switching time. The larger value is taken from the minimum time of the engine mechanical change, as follows:

[0131]

[0132] in, is the preset time length value, I EJK is a preset engine speed difference response capability coefficient;

[0133] Among them, see Figure 5 , when in the energy continuous over-discharge stage, that is Figure 5 In the C stage, the battery target current I of the current stage is determined according to the over-discharge energy of the over-discharge stage. CB3 According to the I CB3 Calculate the motor target electric power P at the current stage PM3 According to the P PM3 Calculate the mechanical target torque of the motor at the current stage According to the Calculate the target net output torque of the engine at the current stage According to the Control the engine output corresponding torque;

[0134] Specifically, in the continuous over-discharge control stage, the over-discharge power of the battery is used for continuous discharge. From the control point of view, considering the frequent switching between over-discharge and over-charge of the battery, which causes the back-and-forth adjustment of the powertrain, it is necessary to define the minimum time of the over-discharge stage combined with the B stage and the C stage. In addition, considering the long-term cumulative effect and the influence of temperature, the general practice is to keep the battery in a state of micro-over-discharge in the SOC balance cycle, and define the battery energy micro-over-discharge factor γ. Therefore, the control continuous over-discharge time of the C stage can be obtained as follows:

[0135]

[0136]

[0137] Among them, t C is the duration of stage C; It is the minimum duration of the over-discharge phase of the combined B and C phases in a cycle;

[0138] According to the integration of the net discharge power of the battery in stages B and C above, the total over-discharge energy can be calculated as follows:

[0139]

[0140] The battery over-discharge energy can be obtained from formula (18) to get the end of continuous over-discharge, that is, the battery target current I in the current C stage CB3 as follows:

[0141]

[0142] Since this process exists in the battery discharge current and the motor charging current, considering the accessory power, the current C stage charge and discharge equivalent power P can be estimated PC3 as follows:

[0143]

[0144] The charge and discharge equivalent power P from formula (20) PC3 The motor target electric power P of the current C stage can be obtained PM3 as follows:

[0145]

[0146] Considering that the subsequent idle charging switches from the over-discharge stage to the over-charge stage, the engine speed also needs to return to the target idle speed requirement. Therefore, the motor speed at this stage It can be calibrated to about 60% of the overshoot idle speed as the idle power control target. Combined with the motor target electric power in formula (21), the mechanical target torque of the motor in the current C stage can be obtained: and the target net output torque of the engine as follows:

[0147]

[0148]

[0149] in, The motor speed value corresponding to the preset C stage, in rpm;

[0150] Wherein, the battery overcharging stage includes an energy overcharging switching stage and an energy continuous overcharging stage;

[0151] Specifically, after the battery energy over-discharge control, the SOC value of the battery will drop by one value in the accuracy range to reach the lower limit of the SOC balance energy; in order to meet the accuracy of the battery energy balance range, the battery over-discharge state needs to be converted into an over-charge state; similar to the over-discharge control, it can be divided into two stages: the energy over-charge switching stage and the energy continuous over-charge stage, corresponding to Figure 5 The D and E phases.

[0152] Among them, see Figure 5 When in the energy overcharge switching stage, the maximum current allowed by the battery overcharge control is set according to the overcharge energy in the overcharge stage and the preset calibration Determine the battery target current I in the current stage CB4 According to the I CB3 Calculate the motor target electric power P at the current stage PM4 According to the P PM4 Calculate the mechanical target torque of the motor at the current stage According to the Calculate the target net output torque of the engine at the current stage According to the Control the engine output corresponding torque;

[0153] Specifically, the charging current of the battery when switching from continuous over-discharge control to over-charge control must not only consider the definition of the maximum over-charge current, but also the frequency of switching between over-discharge and over-charge regulation of SOC balance control under the entire idle condition. If the switching frequency is too high, it is easy to cause oscillation of the powertrain. Therefore, the battery target current I CB4 The following formula can be used for estimation:

[0154]

[0155] Among them, V CB4 is the battery voltage at this time, t D+E It is the sum of the duration of the D phase and the E phase (overcharge phase). The maximum current allowed for the pre-set battery overcharge control;

[0156] The current D stage charge and discharge equivalent power P can be calculated from the target overcharge current PC4 and the target charging power P of the motor PM4 as follows:

[0157]

[0158]

[0159] The motor target electric power P in the current D phase PM4 The corresponding motor mechanical target torque and the net output torque of the engine can be calculated as follows:

[0160]

[0161]

[0162] in, is the motor speed value corresponding to the preset D stage, in rpm; t D is the duration of the current D phase;

[0163] Since the mechanical response of the engine is significantly slower than the change in electrical power, instantaneous overshoot often occurs in the actual control process, causing the speed to be instantly lowered. The range of speed overshoot is estimated as follows:

[0164]

[0165] Among them, see Figure 5 When the energy is in the continuous overcharge stage, according to the overcharge energy in the overcharge stage, the I CB3 And the I CB4 Determine the battery target current I in the current stage CB6 According to the I CB6 Calculate the motor target electric power P at the current stage PM6 According to the P PM6 Calculate the mechanical target torque of the motor at the current stage According to the Calculate the target net output torque of the engine at the current stage According to the Control the engine output corresponding torque.

[0166] Specifically, the target ▽E is increased according to the overcharge time and battery energy. W The battery target current I at the end of continuous overcharge can be calculated CB6 :

[0167]

[0168] Among them, t E is the duration of the current E phase;

[0169] If the battery charging current is to be controlled by constant current during the continuous overcharge stage, that is, I CB6 To be equal to I CB4 By combining equation (30) with equation (24) and considering the relationship of equal energy gradients, we can obtain ICB4 with I CB3 The satisfied relationship is as follows:

[0170]

[0171] Among them, t B+C is the length of time of the over-discharge phase, t D+E is the length of time of the overcharge phase;

[0172] In the above formula, the continuous overcharge charging time t E In actual control, the influence of the maximum charging current and the entire minimum overcharge charging time also need to be considered, so the actual time estimation is carried out as follows:

[0173]

[0174] in, The minimum time length for the entire overcharge charge is preset;

[0175] According to formula (30), the target overcharge current I CB6 and accessory power P 附件 The charge and discharge equivalent power P can be calculated PC6 and the motor's target electric power P PM6 as follows:

[0176]

[0177]

[0178] P PB6 =P PB4 =I CB4 ·V CB4 (35)

[0179] Among them, V CB6 is the battery voltage at the end of continuous overcharge;

[0180] The current E-stage motor mechanical target torque can be obtained from formula (33): and the target net output torque of the engine as follows:

[0181]

[0182]

[0183] in, It is the motor speed value corresponding to the preset E stage, in rpm.

[0184] Based on the above description, it can be seen that this embodiment has the following advantages:

[0185] (1) The control target is easy to understand, and the engine charging torque is derived from the target;

[0186] (2) The battery charging current fluctuation range can be accurately guaranteed, making it less likely that high current charging will damage the battery;

[0187] (3) The switching frequency between over-discharge and over-charge can be defined in advance, which can accurately ensure the switching frequency of the engine's control target torque during the idling charging process, thereby achieving better energy consumption;

[0188] (4) The battery energy fluctuation range allowed by the battery SOC balance control is small, which can greatly utilize the battery capacity and provide guarantees for vehicle energy utilization and battery safety.

[0189] See also Figure 6 Another embodiment of the present invention provides a vehicle torque control system, the system is used to implement the vehicle torque control method described in the above embodiment, when the vehicle is in an idle charging state, the engine net output torque control in the battery over-discharge stage and over-charge stage is cyclically and alternately performed;

[0190] Wherein, the system comprises:

[0191] an over-discharge stage control unit 1, used to control the net output torque of the engine in the over-discharge stage, determine the corresponding target net output torque of the engine according to the over-discharge energy in the over-discharge stage, and control the engine to output a corresponding torque according to the target net output torque of the engine; and

[0192] An overcharging stage control unit 2, used to control the net output torque of the engine in the overcharging stage, determine the corresponding target net output torque of the engine according to the overcharging energy in the overcharging stage, and control the engine to output a corresponding torque according to the target net output torque of the engine;

[0193] Optionally, the system further comprises:

[0194] The control unit 3 of the idle trickle charging stage is used to control the net output torque of the engine in the idle trickle charging stage before entering the first over-discharge stage. According to the formula Calculate the battery target current I at the current stage CB1 According to the I CB1 Calculate the motor target electric power P at the current stage PM1 According to the P PM1 Calculate the mechanical target torque of the motor at the current stage And, according to the Calculate the target net output torque of the engine at the current stage According to the Control the engine output corresponding torque;

[0195] in, To charge the battery in the idle trickle charging stage, V CB1 is the current battery voltage, t A The length of the idle trickle charge phase.

[0196] The system embodiment described above is merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0197] It should be noted that the system described in the above embodiment corresponds to the method described in the above embodiment. Therefore, the undetailed parts of the system described in the above embodiment can be obtained by referring to the contents of the method described in the above embodiment, and will not be repeated here.

[0198] Furthermore, the vehicle torque control system described in the above embodiment, if implemented in the form of a software functional unit and sold or used as an independent product, can be stored in a computer-readable storage medium.

[0199] Another embodiment of the present invention provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the vehicle torque control method described in the above embodiment is implemented.

[0200] Exemplarily, the computer-readable storage medium may include: any entity or device capable of carrying the computer program code, recording medium, USB flash drive, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal and software distribution medium, etc.

[0201] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or technical improvements in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A vehicle torque control method, characterized in that: The method comprises: When the vehicle is in an idle charging condition, the net output torque control of the engine is performed alternately in the over-discharge stage and the over-charge stage of the battery; the over-discharge stage means that the battery is equivalent to providing electrical energy in the entire vehicle idle condition, and the over-charge stage means that the battery is equivalent to a load in the entire vehicle idle condition; In the over-discharge stage, the corresponding target net output torque of the engine is determined according to the over-discharge energy of the over-discharge stage, and the engine is controlled to output the corresponding torque according to the target net output torque of the engine; the over-discharge energy of the previous over-discharge stage is 1+γ times the over-discharge energy of the current over-discharge stage; In the overcharging stage, the corresponding target net output torque of the engine is determined according to the overcharging energy of the overcharging stage, and the engine is controlled to output the corresponding torque according to the target net output torque of the engine; the overcharging energy of the previous overcharging stage is 1+γ times the overcharging energy of the current overcharging stage; Wherein, γ is a cycle battery over-discharge coefficient that is preset to be greater than 0.

2. The vehicle torque control method according to claim 1, characterized in that: The battery overdischarge stage includes an energy overdischarge switching stage and an energy continuous overdischarge stage; Among them, when in the energy over-discharge switching stage, according to the preset motor target electric power P PM2 Calculate the mechanical target torque of the motor at the current stage According to the Calculate the target net output torque of the engine at the current stage According to the Control the engine output corresponding torque; When the energy is in the continuous over-discharge stage, the battery target current I of the current stage is determined according to the over-discharge energy of the over-discharge stage. CB3 According to the I CB3 Calculate the motor target electric power P at the current stage PM3 According to the P PM3 Calculate the mechanical target torque of the motor at the current stage According to the Calculate the target net output torque of the engine at the current stage According to the Control the engine output corresponding torque.

3. The vehicle torque control method according to claim 2, characterized in that: The battery overcharge stage includes an energy overcharge switching stage and an energy continuous overcharge stage; Among them, when in the energy overcharge switching stage, the maximum current allowed by the battery overcharge control is set according to the overcharge energy in the overcharge stage and the preset calibration Determine the battery target current I in the current stage CB4 According to the I CB3 Calculate the motor target electric power P at the current stage PM4 According to the P PM4 Calculate the mechanical target torque of the motor at the current stage According to the Calculate the target net output torque of the engine at the current stage According to the Control the engine output corresponding torque; Wherein, when in the energy continuous overcharge stage, according to the overcharge energy in the overcharge stage, the I CB3 And the I CB4 Determine the battery target current I at the current stage CB6 According to the I CB6 Calculate the motor target electric power P at the current stage PM6 According to the P PM6 Calculate the mechanical target torque of the motor at the current stage According to the Calculate the target net output torque of the engine at the current stage According to the Control the engine output corresponding torque.

4. The vehicle torque control method according to claim 3, characterized in that: The method further comprises: Before entering the first over-discharge stage, the net output torque of the engine is controlled during the idle trickle charging stage; The net output torque control of the engine during the idle trickle charging stage includes: According to the formula Calculate the battery target current I at the current stage CB1 ;in To charge the battery in the idle trickle charging stage, V CB1 is the current battery voltage, t A The length of the idle trickle charging phase; According to the I CB1 Calculate the motor target electric power P at the current stage PM1 ; According to the P PM1 Calculate the mechanical target torque of the motor at the current stage According to the Calculate the target net output torque of the engine at the current stage According to the Control the engine output corresponding torque.

5. The vehicle torque control method according to claim 4, characterized in that: The method further comprises: When in the energy over-discharge switching stage, the battery target current I of the current stage is calculated according to the following formula: CB2 : P PC2 =P 附件 +P PM2 Among them, P PB2 is the battery target power during the energy over-discharge switching phase, V CB2 is the current battery voltage, P PC2 is the charge and discharge equivalent power in the energy over-discharge switching stage, P 附件 is the vehicle accessory power, I CC2 is the charge and discharge equivalent current, The maximum current allowed for battery over-discharge control is preset. is the equivalent resistance from the motor to the accessory end, is the equivalent resistance from the battery to the accessory terminal; When the energy is in the continuous over-discharge stage, the battery target current I of the current stage is calculated and determined according to the following formula: CB3 : in, is the over-discharge energy in the over-discharge stage, t B is the duration of the energy over-discharge switching phase, t C The duration of the energy over-discharge stage; The motor target electric power P at the current stage is calculated according to the following formula: PM3 : Among them, P PC3 It is the charging and discharging equivalent power during the continuous over-discharge stage of energy.

6. The vehicle torque control method according to claim 5, characterized in that: in, t C The values ​​are as follows: in, It is the minimum value of the sum of the preset time lengths of the energy over-discharge switching phase and the energy continuous over-discharge phase.

7. The vehicle torque control method according to claim 5, characterized in that: The method further comprises: When in the energy overcharge switching stage, the battery target current I of the current stage is calculated and determined according to the following formula: CB4 : in, is the overcharge energy in the overcharge stage, V CB4 is the current battery voltage, t D+E is the duration of the overcharge phase; The motor target electric power P at the current stage is calculated according to the following formula: PM4 : Among them, P PC4 It is the charge and discharge equivalent power in the energy overcharge switching stage.

8. The vehicle torque control method according to claim 7, characterized in that: The method further comprises: When the energy is in the continuous overcharge stage, the battery target current I of the current stage is calculated and determined according to the following formula: CB6 : Among them, t D is the duration of the energy overcharge switching phase, t E The duration of the energy overcharge phase; The motor target electric power P at the current stage is calculated according to the following formula: PM6 : P PB6 =P PB4 =I CB4 ·V CB4 Among them, V CB6 is the current battery voltage.

9. The vehicle torque control method according to claim 8, characterized in that: in, t E The values ​​of are as follows: in, It is the minimum value of the sum of the preset durations of the energy overcharge switching phase and the energy continuous overcharge phase.

10. A vehicle torque control system, characterized in that: Used to implement the vehicle torque control method according to any one of claims 1 to 9, when the vehicle is in an idle charging condition, the net output torque control of the engine in the over-discharge stage and the over-charge stage of the battery is cyclically and alternately performed; the over-discharge stage means that the battery is equivalent to providing electrical energy in the entire vehicle idle condition, and the over-charge stage means that the battery is equivalent to a load in the entire vehicle idle condition; Wherein, the system comprises: an over-discharge stage control unit, used to control the net output torque of the engine in the over-discharge stage, determine the corresponding target net output torque of the engine according to the over-discharge energy in the over-discharge stage, and control the engine to output a corresponding torque according to the target net output torque of the engine; the over-discharge energy in the previous over-discharge stage is 1+γ times the over-discharge energy in the current over-discharge stage; and an overcharging stage control unit, used to control the net output torque of the engine in the overcharging stage, determine the corresponding target net output torque of the engine according to the overcharging energy in the overcharging stage, and control the engine to output the corresponding torque according to the target net output torque of the engine; the overcharging energy in the previous overcharging stage is 1+γ times the overcharging energy in the current overcharging stage; Wherein, γ is a cycle battery over-discharge coefficient that is preset to be greater than 0.

11. The vehicle torque control system according to claim 10, characterized in that: The system further comprises: The idle trickle charging stage control unit is used to control the net output torque of the engine in the idle trickle charging stage before entering the first over-discharge stage. According to the formula Calculate the battery target current I at the current stage CB1 According to the I CB1 Calculate the motor target electric power P at the current stage PM1 According to the P PM1 Calculate the mechanical target torque of the motor at the current stage And, according to the Calculate the target net output torque of the engine at the current stage According to the Control the engine output corresponding torque; in, To charge the battery in the idle trickle charging stage, V CB1 is the current battery voltage, t A The length of the idle trickle charge phase.

12. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the vehicle torque control method according to any one of claims 1 to 9 is implemented.

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