A vehicle driving mode control method based on virtual dual batteries

Abstract

The present invention discloses a vehicle driving mode control method based on virtual dual batteries, wherein two virtual batteries are set, namely, an energy recovery battery and a driving power generation battery; when the vehicle is powered on, the vehicle operation mode and the state of the virtual battery are determined according to the power battery SOC and torque; when the virtual battery state is first determined to be the energy recovery battery state, the accessory power consumption α is calculated; as the power battery power is consumed, when the virtual battery state is determined to be the driving power generation battery state and the vehicle operation mode is the driving power generation mode, the difference β between the motor power generation and the accessory power consumption is calculated; a calibration threshold is determined based on α and β; and the operation mode of the vehicle after exiting the driving power generation mode is determined based on the power battery SOC and the calibration threshold. The present invention can utilize energy more reasonably, thereby reducing efficiency loss.

Description

Technical Field

[0001] The present invention belongs to the technical field of automobile control, and in particular relates to an automobile driving mode control method based on virtual dual batteries. Background Art

[0002] Hybrid vehicles are a new generation of vehicle structure that combines the advantages of electric vehicles and traditional vehicles. They generally have at least two energy sources, which complement each other to improve the performance of the entire vehicle system. To achieve the coordinated work between the two, a good control strategy is required. The control strategy is the soul of hybrid vehicles. It dynamically allocates the output power of the engine and motor system according to the energy requirements of the power system during the driving process of the vehicle. Using different control strategies can achieve the optimal design goals, including the best fuel economy, the lowest emissions, the lowest system cost, and the best driving performance.

[0003] like Figure 1 The figure shows the driving mode of the vehicle under different vehicle torque requirements and power battery charge states. In different vehicle torque requirements and different power battery charge state ranges, the vehicle's operating mode switches between engine-only drive, driving power generation, hybrid, and pure electric modes. The disadvantage of this solution is that when the SOC value of the power generated in the driving power generation mode (EM) reaches the threshold a, the driving mode will switch to hybrid drive or pure motor drive, that is, the power generated by driving participates in driving the vehicle. When the power consumption is below the threshold a, it will enter the driving power generation mode again. The power generated by driving should be mainly used for the power consumption of electric accessories. If the power generated by driving is used for motor drive, the efficiency of the whole vehicle will be greatly reduced due to the loss of motor and battery charging and discharging efficiency. Summary of the invention

[0004] The purpose of the present invention is to solve the deficiencies of the above-mentioned background technology and to provide a vehicle driving mode control method based on virtual dual batteries, which can reduce efficiency loss and utilize energy more reasonably.

[0005] The technical solution adopted by the present invention is: a vehicle driving mode control method based on virtual dual batteries, setting two virtual batteries, namely an energy recovery battery and a driving power generation battery;

[0006] When the vehicle is powered on, the vehicle's operating mode and the state of the virtual battery are determined based on the power battery SOC and torque;

[0007] When the virtual battery state is determined to be an energy recovery battery state for the first time, the accessory power consumption α is calculated;

[0008] As the power battery is consumed, when it is determined that the virtual battery state is the driving power generation battery state and the vehicle operation mode is the driving power generation mode, the difference β between the motor power generation and the accessory power consumption is calculated;

[0009] Determine a calibration threshold based on α and β;

[0010] The operating mode of the vehicle after exiting the driving power generation mode is determined based on the size of the power battery SOC and the calibration threshold.

[0011] Further, when the power battery SOC>C4, the virtual battery state is judged to be the energy recovery battery state; when the power battery SOC≤C4, the virtual battery state is judged to be the driving power generation battery state.

[0012] Furthermore, the operating mode of the vehicle is defined as follows:

[0013] When the power battery SOC≤C7, the operation mode is parking power generation mode;

[0014] Power battery C7<SOC≤C6, the operation mode is driving power generation mode;

[0015] Power battery C6<SOC≤C4, the operating mode is engine mode;

[0016] When the power battery C4<SOC≤C2 and the torque T≤e, the operation mode is pure electric mode;

[0017] When the power battery C4<SOC≤C2 and the torque T>e, or C2<SOC≤C1, the operation mode is the hybrid drive mode;

[0018] When the power battery SOC is greater than C1, the operation mode is energy recovery prohibited.

[0019] Furthermore, the power consumption α of the accessory is the power that the driving power generation battery owes to the energy recovery battery.

[0020] Furthermore, the difference β between the power generated by the motor and the power consumed by the accessories is the power returned by the driving power generation battery to the energy recovery battery.

[0021] Furthermore, the process of determining the calibration threshold based on α and β is as follows: calibrate the power interval table, calculate the difference δ between α and β, and determine the interval power corresponding to the difference δ by looking up the power interval table according to the difference δ. The sum of the interval power and C4 is the calibration threshold.

[0022] Furthermore, the power is evenly divided into multiple power intervals, each power interval corresponds to a level, and each level corresponds to an interval power, forming a power interval table. When looking up the power interval table, δ is compared with each power interval to determine the level of the power interval in which δ is located, and the interval power is determined based on the level.

[0023] Furthermore, in the driving power generation mode, when the power battery SOC satisfies: the calibration threshold value <SOC ≤ C2, and the torque T ≤ e, it is determined that the vehicle exits the driving power generation mode and enters the pure electric mode.

[0024] Furthermore, in the driving power generation mode, when the power battery SOC satisfies: the calibration threshold value <SOC ≤ C2 and the torque T> e, it is determined that the vehicle exits the driving power generation mode and enters the hybrid drive mode.

[0025] Furthermore, in the driving power generation mode, when the power battery SOC satisfies: SOC>calibrated threshold value and SOC>C2, it is determined that the vehicle exits the driving power generation mode and enters the hybrid drive mode.

[0026] The beneficial effects of the present invention are:

[0027] The present invention divides the automobile power battery into two virtual batteries, namely, an energy recovery battery and a driving power generation battery. The two batteries are added together to form the real power battery power. The driving power generation battery is only used to drive accessories, while the energy recovery battery is used to drive the vehicle. When the driving power generation battery is insufficient, a portion of the power can be transferred from the energy recovery battery to drive accessories. When driving power generation is required later, the power transferred in the early stage needs to be returned to the energy recovery battery. The vehicle operation mode switching based on this method uses the power generated by driving power to drive accessories and uses the power recovered to drive the vehicle. This can make more reasonable use of energy and reduce efficiency loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the driving mode of the prior art.

[0029] Figure 2 Schematic diagram of the operating mode of the present invention.

[0030] Figure 3 The control flow chart of the present invention is DETAILED DESCRIPTION

[0031] The specific embodiments of the present invention are further described below in conjunction with the accompanying drawings. It should be noted that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation of the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0032] like Figure 2 , Figure 3 As shown, the present invention provides a vehicle driving mode control method based on virtual dual batteries, setting two virtual batteries, namely an energy recovery battery and a driving power generation battery;

[0033] When the vehicle is powered on, the power battery SOC is detected in real time, and the vehicle's operating mode and the status of the virtual battery are determined based on the power battery SOC and torque;

[0034] When the virtual battery state is determined to be the energy recovery battery state for the first time, the accessory power consumption α is calculated, that is, the amount of power that the driving power generation battery owes to the energy recovery battery.

[0035] As the power battery is consumed, when the virtual battery state is determined to be the driving power generation battery state and the vehicle's operating mode is the driving power generation mode, the difference β between the motor power generation and the accessory power consumption is calculated, that is, the power returned by the driving power generation battery to the energy recovery battery.

[0036] Determine a calibration threshold based on α and β;

[0037] The operating mode of the vehicle after exiting the driving power generation mode is determined based on the size of the power battery SOC and the calibration threshold.

[0038] The above control process is specifically as follows: assuming that when the power battery SOC is SOC≤C4 when the car is powered on, the battery state is defined as the driving power generation battery state; when SOC>C4, the battery state is the energy recovery battery state.

[0039] If the battery state is determined to be in the energy recovery battery state for the first time, the power consumption of the accessories (air conditioning, EPS steering, etc.) is integrated to obtain the power consumption value of the accessories. As mentioned above, the electric energy generated by the vehicle should be used for the operation of the accessories, that is, the power consumption of the accessories should be provided by the vehicle power generation battery, but because the current battery state is in the energy recovery battery state, this part of the power consumption is calculated as the power consumption of the vehicle power generation battery that is less than the energy recovery battery. The calculation of the power consumption of the accessory is set to α, which is the integral calculation of the power consumption of the accessory in the energy recovery state, and is also the power consumption of the vehicle power generation battery that is less than the energy recovery battery.

[0040] When the SOC gradually decreases to ≤C4, it switches to the engine single-drive mode. When the SOC continues to decrease to ≤C6, it switches to the driving power generation mode. In the driving power generation mode, the difference β between the power generation of the motor and the power consumption of the accessories is calculated by integration. The integral calculated difference power β is the power returned by the driving power generation battery to the energy recovery battery. The energy balance of the whole vehicle is judged, that is, the accumulated power β returned by the driving power generation battery to the energy recovery battery in the driving power generation battery state, and the difference between the power consumption α of the accessories in the previous energy recovery battery state is calculated as δ, that is, δ = α-β. The calibration power interval table divides a calibrated power (such as 30%) into multiple power intervals (such as 5 power intervals), each power interval corresponds to a level, and each level corresponds to an interval power γ. The relationship between δ and the corresponding power interval is queried to determine which level it is in, and then the interval power γ corresponding to δ is determined. The interval power γ is used as the hysteresis interval, that is, γ_1, γ_2...γ_n correspond to n levels of interval power respectively. The hysteresis interval γ plus C4 is used as the calibration threshold to determine the driving form after exiting driving power generation.

[0041] If it is initially determined that the battery state is in the driving power generation battery state, this state is maintained and its specific operation mode is determined according to the SOC until SOC>C4, when it enters the energy recovery battery and then calculates the power consumption of the above accessories.

[0042] In the above scheme, when the power battery SOC>C4, the virtual battery state is judged as the energy recovery battery state; when the power battery SOC≤C4, the virtual battery state is judged as the driving power generation battery state, and C4 is the calibrated hysteresis value. To avoid the situation where the SOC is too high or too low, it can be divided more finely, such as when the power battery C4<SOC≤C1, the virtual battery state is judged as the energy recovery battery state, and C1 is the power threshold for prohibiting energy recovery.

[0043] In the above scheme, the operation mode of the vehicle is defined as follows:

[0044] When the power battery SOC≤C7, the operation mode is parking power generation mode;

[0045] Power battery C7<SOC≤C6, the operation mode is driving power generation mode;

[0046] Power battery C6<SOC≤C4, the operating mode is engine mode;

[0047] When the power battery C4<SOC≤C2 and the torque T≤e, the operation mode is pure electric mode;

[0048] When the power battery C4<SOC≤C2 and the torque T>e, or C2<SOC≤C1, the operation mode is the hybrid drive mode;

[0049] When the power battery SOC is greater than C1, the operation mode is energy recovery prohibited.

[0050] Among them, C2 and C6 are the calibrated power thresholds between different modes, and C7 is the power threshold that is insufficient for driving.

[0051] In the above scheme, the process of determining the calibration threshold based on α and β is:

[0052] Calibration power interval table: Divide the power into multiple power intervals evenly, each power interval corresponds to a level, and each level corresponds to an interval power.

[0053] Calculate the difference δ between α and β, compare δ with each power interval, determine the level of the power interval in which δ is located, determine the interval power corresponding to δ based on the level, and then the sum of the interval power and C4 is the calibration threshold.

[0054] In the above scheme, in the driving power generation mode:

[0055] When the power battery SOC satisfies: the calibration threshold value < SOC ≤ C2, and the torque T ≤ e, it is determined that the vehicle exits the driving power generation mode and enters the pure electric mode.

[0056] When the power battery SOC satisfies: the calibration threshold value < SOC ≤ C2, and the torque T > e, it is determined that the vehicle exits the driving power generation mode and enters the hybrid drive mode.

[0057] When the power battery SOC satisfies: C2<SOC≤C1, and SOC>calibrated threshold value, it is determined that the vehicle exits the driving power generation mode and enters the hybrid drive mode.

[0058] When the SOC of the power battery instantly reaches above C1 due to abnormal conditions, energy recovery is prohibited.

[0059] Example

[0060] 1. When the SOC is high (such as higher than C4 and lower than C2) and there is recovered reserve energy, and the percentage of vehicle drive power demand is low (that is, torque T≤e), pure electric mode is adopted and virtual power is calculated.

[0061] 2. When the SOC is high (such as higher than C4 and lower than C2) and there is recovered reserve energy, and when the percentage of vehicle drive power demand is high (that is, torque T>e), hybrid drive mode is adopted and virtual power is calculated.

[0062] 3 When the SOC is low (such as lower than C4 and higher than C6), pure engine driving is adopted. In this mode, if the braking energy recovery is large and the SOC does not decrease or increase, when the SOC rises to higher than C4, it is switched to pure electric mode or hybrid drive mode according to the torque size; if in pure engine mode, the SOC continues to drop to lower than C6, it is switched to driving power generation mode and the above-mentioned virtual power calculation is used.

[0063] 4. When the SOC is low (such as lower than C6 and higher than C7), driving power generation is adopted. After the driving power generation determines that the energy income and expenditure of the whole vehicle are balanced, if the SOC exceeds the calibration threshold (γ+C4), the driving power generation is exited and the pure electric mode or hybrid drive mode is entered.

[0064] 5. When the SOC is extremely low (such as lower than C7), in extreme cases, the vehicle will be parked and enter the parking charging mode.

[0065] 6. When the SOC is extremely high (such as higher than C1), energy recovery will be prohibited.

[0066] The analysis method for judging the energy balance of the whole vehicle is as follows:

[0067] During driving, the hybrid controller first determines the battery status of the vehicle's operating mode. When it is in the energy recovery battery state, the accessory work integral is calculated to obtain the power consumed by the accessory. The power consumed by the accessory should be provided by the driving power generation battery, but because the current battery state is in the energy recovery battery state, the power consumed is the power that the driving power generation battery owes to the energy recovery battery.

[0068] If the current state is the driving power generation battery, the motor power generation is integrated to obtain the driving power generation. As mentioned above, the driving power generation is used to drive accessories, and the energy recovery is used to drive the vehicle. Therefore, the power generation obtained by the integral calculation should be used to drive accessories. As mentioned above, in the energy recovery battery state, the power that the driving power generation battery owes to the energy recovery battery is calculated, so the driving power generation should be returned to the energy recovery battery.

[0069] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. The contents not described in detail in this specification belong to the prior art known to professional and technical personnel in the field.

Claims

1. A vehicle driving mode control method based on virtual dual batteries, characterized in that: Two virtual batteries are set, namely the energy recovery battery and the driving power generation battery; when the vehicle is powered on, the vehicle's operating mode and the state of the virtual battery are determined according to the power battery SOC and the vehicle's required torque; When the virtual battery state is first determined to be an energy recovery battery state, the power consumption of the accessory α is calculated; as the power of the power battery is consumed, when the virtual battery state is determined to be a driving power generation battery state and the vehicle's operating mode is a driving power generation mode, the difference β between the motor power generation and the power consumption of the accessory is calculated; a calibration threshold is determined based on α and β; and the operating mode of the vehicle after exiting the driving power generation mode is determined based on the size of the power battery SOC and the calibration threshold; When the power battery SOC>C4, the virtual battery state is judged to be the energy recovery battery state; when the power battery SOC≤C4, the virtual battery state is judged to be the driving power generation battery state; The operating mode of the vehicle is defined as follows: when the power battery SOC≤C7, the operating mode is the parking power generation mode; when the power battery C7<SOC≤C6, the operating mode is the driving power generation mode; when the power battery C6<SOC≤C4, the operating mode is the engine mode; when the power battery C4<SOC≤C2 and the vehicle requires a torque of T≤e, the operating mode is the pure electric mode; when the power battery C4<SOC≤C2 and the vehicle requires a torque of T>e, or C2<SOC≤C1, the operating mode is the hybrid drive mode; when the power battery SOC>C1, the operating mode is the energy recovery prohibited mode.

2. The vehicle driving mode control method based on virtual dual batteries according to claim 1 is characterized in that: The power consumption α of the accessory is the power of the driving power generation battery that is less than the power of the energy recovery battery.

3. The vehicle driving mode control method based on virtual dual batteries according to claim 1 is characterized in that: The difference β between the power generated by the motor and the power consumed by the accessories is the power returned by the driving power generation battery to the energy recovery battery.

4. The vehicle driving mode control method based on virtual dual batteries according to claim 1 is characterized in that: The process of determining the calibration threshold based on α and β is as follows: calibrate the power interval table, calculate the difference δ between α and β, and determine the interval power corresponding to the difference δ by looking up the power interval table according to the difference δ. The sum of the interval power and C4 is the calibration threshold.

5. The vehicle driving mode control method based on virtual dual batteries according to claim 1 is characterized in that: The power is evenly divided into multiple power intervals, each power interval corresponds to a level, and each level corresponds to an interval power, forming a power interval table. When looking up the power interval table, δ is compared with each power interval to determine the level of the power interval in which δ is located, and the interval power is determined based on the level.

6. The vehicle driving mode control method based on virtual dual batteries according to claim 1 is characterized in that: In the driving power generation mode, when the power battery SOC meets: the calibration threshold <SOC≤C2, and the vehicle demand torque T≤e, it is determined that the vehicle exits the driving power generation mode and enters the pure electric mode.

7. The vehicle driving mode control method based on virtual dual batteries according to claim 1 is characterized in that: In the driving power generation mode, when the power battery SOC satisfies: the calibration threshold value <SOC ≤ C2 and the vehicle demand torque T> e, it is determined that the vehicle exits the driving power generation mode and enters the hybrid drive mode.

8. The vehicle driving mode control method based on virtual dual batteries according to claim 1 is characterized in that: In the driving power generation mode, when the power battery SOC satisfies: SOC>calibrated threshold and SOC>C2, it is determined that the vehicle exits the driving power generation mode and enters the hybrid drive mode.

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