Large-electric-quantity range-extended electric vehicle calibration method

Abstract

The invention discloses a large-electric-quantity range-extending type electric vehicle calibration method. An overall calibration framework comprises driving mode calibration, energy management calibration, battery low-temperature protection calibration, battery discharge limit calibration and electric drive external characteristic limit calibration. Adaptive calibration is carried out on functional modules such as mode management and energy management of a large-electric-quantity extended-range electric commercial vehicle, the whole vehicle only discharges a battery under most working conditions, the consumption ratio of electricity and oil is reasonably distributed, meanwhile, the system configuration advantages are exerted, the dynamic property of the whole vehicle is guaranteed as much as possible, meanwhile, overcharge protection of the battery is considered, and the system reliability is improved. The car using income of a user is maximized, greater value is created for the user, and core parts are also protected; the VCU dynamically adjusts the allowable power generation power of the APU in real time according to the available charging power of the battery, it is guaranteed that the battery cannot be overcharged under the dynamic working condition, the braking energy efficiency and the braking performance are guaranteed, abrasion of mechanical braking is reduced, and the battery is protected.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy vehicles, and in particular to a calibration method for a large-capacity extended-range electric vehicle. Background Art

[0002] Extended-range electric commercial vehicles equipped with large-capacity batteries have higher battery power and can support longer pure electric driving range. Therefore, under the control framework of traditional extended-range electric vehicles, the battery should be discharged as much as possible to power the electric drive to drive the vehicle in different driving modes, and the APU will assist in operation to minimize fuel consumption and increase user benefits.

[0003] There are many problems with the mode management and energy management calibration of large-capacity extended-range electric commercial vehicles and low-capacity extended-range electric commercial vehicles in the existing technology. The proportion of oil and electricity used in the whole vehicle is not adaptively adjusted, which increases the fuel consumption of users and reduces the benefits of using the vehicle. Summary of the invention

[0004] The present invention provides a calibration method for a large-capacity extended-range electric vehicle, which can adaptively adjust the usage ratio of oil and electricity of the whole vehicle, thereby avoiding an increase in the fuel consumption of the user and improving the user's vehicle benefits.

[0005] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a calibration method for a large-capacity extended-range electric vehicle, wherein the overall calibration framework includes a driving mode calibration, an energy management calibration, a battery low-temperature protection calibration, a battery discharge limit calibration and an electric drive external characteristic limit calibration; The specific calibration method is as follows: Step S1, driving mode calibration. When there is a heating request in different driving modes, the VCU will control the engine to start to provide a warm air heat source for the passenger compartment. The driving mode is changed due to the intervention of the heating request. However, in order to avoid the driver's confusion about the driving mode, when entering the heating mode in different calibration modes, the driving mode before entering the heating mode is maintained, and the target driving mode cannot be switched by clicking the driving mode switch during heating. Step S2, energy management calibration. The full-load mass of the large-power range extender is larger than that of the low-power range extender, and the driving power demand on the driving end is also greater. For the basic power conservation map of battery conservation, it is necessary to adaptively increase the power conservation power. For the battery conservation map of coasting and neutral gear, the power conservation power is adaptively increased by 5~10kW to replenish the battery faster and meet the power consumption of the large driving power demand. Step S3, battery low temperature protection calibration. For extended-range electric vehicles, due to the presence of the APU, when the battery temperature is low in the cold state in winter, the battery charging capacity is low or charging is not allowed. When the driver releases the accelerator to let the vehicle coast or brakes to recover energy, the APU power reduction is slow, resulting in the energy recovery power being established, and the APU power generation power that does not decrease rapidly is superimposed, causing the battery to be overcharged. Therefore, when the battery temperature is calibrated to be lower than 10°C and the battery charging capacity is lower than 5kW, the battery low temperature protection strategy is entered; Step S4, battery discharge limit calibration. In order to protect the battery life, the battery discharge lower limit is set according to the EV mode and the SHEV mode. The EV mode discharge lower limit is further lowered. Step S5, electric drive external characteristic limit calibration, in order to ensure the low-speed climbing dynamics of the whole vehicle, it is necessary to pay attention to releasing all the peak torque capacity of the motor in the constant torque range. When approaching the motor base speed, the motor enters the constant power range and begins to gradually limit the external characteristic torque capacity of the motor to limit the maximum driving power output of the motor.

[0006] Preferably, the step S1, driving mode calibration, comprises the following specific steps: Step S1.1, determine whether there is a heating request, if yes, proceed to step S1.2, if no, proceed to step S1.3; Step S1.2, the external driving mode remains in the pre-heating driving mode; Step S1.3, after the heating request is exited, the driving mode before heating is maintained, and the user is allowed to switch the driving mode freely; Step S1.4, determining whether the driver has pressed the driving mode switch, if so, proceed to step S1.5, if not, repeat this step; Step S1.5: the driving mode remains in the pre-heating driving mode.

[0007] Preferably, the specific content of step S1.3 is: Step S1.31, determine whether the SOC in EV mode is lower than 16% or lower than 18% in SHEV mode, or whether the battery discharge capacity is lower than 35kW. If yes, proceed to step S1.32; otherwise, proceed to step S1.33; Step S1.32, VCU controls the engine to start; Step S1.33, determine whether the battery continuous charging capacity is higher than 60kw, if yes, proceed to step S1.34, if no, proceed to step S1.35; Step S1.34, allowing entry into REV mode; Step S1.35, determine whether the continuous charging capacity is less than 55kw, if yes, proceed to step S1.36, if no, proceed to step S1.37; Step S1.36, prohibiting entry into REV mode; Step S1.37, keep the driving mode unchanged.

[0008] Preferably, the step S2, energy management calibration, comprises the following specific steps: Step S2.1, determine whether the driving mode is REV or EV mode and there is a heating request, if so, proceed to step S2.2. If not, proceed to step S2.3; Step S2.2, the user selects the power generation; Step S2.21, determine whether the battery SOC is greater than or equal to 98%, if so, proceed to step S2.22, if not, proceed to step S2.23; Step S2.24, requesting the power generation to be zero; Step S2.25, generating electricity according to the power selected by the user; Step S2.3, determine whether the driving mode is Auto, if so, proceed to step S2.4; Step S2.4, determine whether the battery SOC is higher than 30%, if yes, proceed to step S2.5, if no, proceed to step S2.6; Step S2.5, keep the battery discharged and prohibit starting the APU to generate electricity; Step S2.6, determine whether the battery SOC is lower than 25%, if so, proceed to step S2.7, if not, repeat this step; Step S2.7, APU power following control; Step S2.8, the basic map of battery power conservation for coasting and braking is all adaptable and marked up by 5~10KW; Step S2.9, the battery power conservation basic map adaptability of the driving condition is increased by 10~20kW.

[0009] Preferably, the step S3, battery low temperature protection calibration, specifically includes: Step S3.1, determine whether the battery's continuous charging capacity is less than 5kw and whether the battery's minimum temperature is less than -10°C. If yes, proceed to step S3.2; otherwise, proceed to step S3.3; Step S3.2, battery low temperature protection; Step S3.21, determine whether the APU is started in REV mode or other modes, if yes, proceed to step S3.22, if no, repeat this step; Step S3.23, executing battery low temperature protection; Step S3.24, VCU constantly requests APU to generate 5kW of power; Step S3.3, determine whether the battery's continuous charging capacity is higher than 10kW, or whether the battery's minimum temperature is higher than -8°C. If yes, proceed to step S3.4. If no, repeat this step. Step S3.4: Do not perform battery low temperature protection.

[0010] Preferably, the step S4, battery discharge limit calibration, specifically includes: Step S4.1, determine whether the driving mode is EV, if yes, proceed to step S4.2, if no, proceed to step S4.3; Step S4.2, when SOC is lower than 16%, the available power of the battery starts to be reduced linearly, and when SOC is 10%, it drops to 0; Step S4.3, the driving mode is SHEV; Step S4.4, when S0C is lower than 18%, the available power of the battery starts to decrease linearly, and drops to 0 at 12%.

[0011] Preferably, the step S5, electric drive external characteristic limit calibration, specifically includes: Step S5.1, driving mode is ECO; Step S5.11, determine whether the speed is lower than the base speed, if yes, proceed to step S5.12. If no, proceed to step S5.13; Step S5.12: No external characteristic limitation is performed below the motor base speed; Step S5.13, the external characteristic torque limit makes the drive power output less than or equal to 90KW; Step S5.2, the driving mode is Normal; Step S5.21, determine whether the speed is lower than the base speed, if yes, proceed to step S5.22. If no, proceed to step S5.23; Step S5.22: No external characteristic limitation is performed below the motor base speed; Step S5.23, the external characteristic torque limit makes the drive power output less than or equal to 110KW.

[0012] The beneficial effects of adopting the above technical solution are: 1. The present invention performs adaptive calibration on functional modules such as mode management and energy management of extended-range electric commercial vehicles with large power, so that the battery is only discharged in most working conditions, and the consumption ratio of electricity and oil is reasonably allocated. At the same time, the advantages of system configuration are brought into play to ensure the power of the whole vehicle as much as possible, while taking into account the overcharge protection of the battery, maximizing the user's vehicle benefits, creating greater value for customers, and protecting core components.

[0013] 2. The VCU of the present invention dynamically and in real time adjusts the APU allowed power generation according to the available charging power of the battery, ensuring that the battery will not be overcharged under dynamic conditions, thereby ensuring the braking energy efficiency and braking performance, reducing the wear of the mechanical brake, and protecting the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is the overall calibration architecture diagram of the present invention; Figure 2 A flow chart for the management and calibration of the mode of the present invention; Figure 3 It is the energy management calibration flow chart of the present invention; Figure 4 This is a low temperature protection calibration flow chart of the present invention; Figure 5 This is a flow chart of the external characteristic limit calibration of the present invention; Figure 6 This is a flow chart of battery discharge limit calibration according to the present invention. DETAILED DESCRIPTION

[0015] The specific implementation methods of the present invention are further explained in detail below by describing the embodiments with reference to the accompanying drawings, with the aim of helping those skilled in the art to have a more complete, accurate and in-depth understanding of the concept and technical solution of the present invention and facilitating its implementation.

[0016] like Figures 1 to 6 As shown, the present invention is a calibration method for a large-capacity extended-range electric vehicle, which adaptively adjusts the usage ratio of oil and electricity in the whole vehicle, thereby avoiding an increase in the user's fuel consumption and improving the user's vehicle benefits.

[0017] Specifically, Figures 1 to 6 As shown, the overall calibration framework includes driving mode calibration, energy management calibration, battery low temperature protection calibration, battery discharge limit calibration and electric drive external characteristic limit calibration; The specific calibration method is as follows: Step S1, driving mode calibration. When there is a heating request in different driving modes, the VCU will control the engine to start to provide a warm air heat source for the passenger compartment. The driving mode is changed due to the intervention of the heating request. However, in order to avoid the driver's confusion about the driving mode, when entering the heating mode in different calibration modes, the driving mode before entering the heating mode is maintained, and the target driving mode cannot be switched by clicking the driving mode switch during heating. Step S2, energy management calibration. The full-load mass of the large-power range extender is larger than that of the low-power range extender, and the driving power demand on the driving end is also greater. For the basic power conservation map of battery conservation, it is necessary to adaptively increase the power conservation power. For the battery conservation map of coasting and neutral gear, the power conservation power is adaptively increased by 5~10kW to replenish the battery faster and meet the power consumption of the large driving power demand. Step S3, battery low temperature protection calibration. For extended-range electric vehicles, due to the presence of the APU, when the battery temperature is low in the cold state in winter, the battery charging capacity is low or charging is not allowed. When the driver releases the accelerator to let the vehicle coast or brakes to recover energy, the APU power reduction is slow, resulting in the energy recovery power being established, and the APU power generation power that does not decrease rapidly is superimposed, causing the battery to be overcharged. Therefore, when the battery temperature is calibrated to be lower than 10°C and the battery charging capacity is lower than 5kW, the battery low temperature protection strategy is entered; Step S4, battery discharge limit calibration. In order to protect the battery life, the battery discharge lower limit is set according to the EV mode and the SHEV mode. The EV mode discharge lower limit is further lowered. Step S5, electric drive external characteristic limit calibration, in order to ensure the low-speed climbing dynamics of the whole vehicle, it is necessary to pay attention to releasing all the peak torque capacity of the motor in the constant torque range. When approaching the motor base speed, the motor enters the constant power range and begins to gradually limit the external characteristic torque capacity of the motor to limit the maximum driving power output of the motor.

[0018] Step S1, driving mode calibration, the specific steps are: Step S1.1, determine whether there is a heating request, if yes, proceed to step S1.2, if no, proceed to step S1.3; Step S1.2, the external driving mode remains in the pre-heating driving mode; Step S1.3, after the heating request is exited, the driving mode before heating is maintained, and the user is allowed to switch the driving mode freely; Step S1.4, determining whether the driver has pressed the driving mode switch, if so, proceed to step S1.5, if not, repeat this step; Step S1.5: the driving mode remains in the pre-heating driving mode.

[0019] The specific content of step S1.3 is: Step S1.31, determine whether the SOC in EV mode is lower than 16% or lower than 18% in SHEV mode, or whether the battery discharge capacity is lower than 35kW. If yes, proceed to step S1.32; otherwise, proceed to step S1.33; Step S1.32, VCU controls the engine to start; Step S1.33, determine whether the battery continuous charging capacity is higher than 60kw, if yes, proceed to step S1.34, if no, proceed to step S1.35; Step S1.34, allowing entry into REV mode; Step S1.35, determine whether the continuous charging capacity is less than 55kw, if yes, proceed to step S1.36, if no, proceed to step S1.37; Step S1.36, prohibiting entry into REV mode; Step S1.37, keep the driving mode unchanged.

[0020] Step S2, energy management calibration, the specific steps are: Step S2.1, determine whether the driving mode is REV or EV mode and there is a heating request, if so, proceed to step S2.2. If not, proceed to step S2.3; Step S2.2, the user selects the power generation; Step S2.21, determine whether the battery SOC is greater than or equal to 98%, if so, proceed to step S2.22, if not, proceed to step S2.23; Step S2.24, requesting the power generation to be zero; Step S2.25, generating electricity according to the power selected by the user; Step S2.3, determine whether the driving mode is Auto, if so, proceed to step S2.4; Step S2.4, determine whether the battery SOC is higher than 30%, if yes, proceed to step S2.5, if no, proceed to step S2.6; Step S2.5, keep the battery discharged and prohibit starting the APU to generate electricity; Step S2.6, determine whether the battery SOC is lower than 25%, if so, proceed to step S2.7, if not, repeat this step; Step S2.7, APU power following control; Step S2.8, the basic map of battery power conservation for coasting and braking is all adaptable and marked up by 5~10KW; Step S2.9, the battery power conservation basic map adaptability of the driving condition is increased by 10~20kW.

[0021] Step S3, battery low temperature protection calibration, the specific contents are as follows: Step S3.1, determine whether the battery's continuous charging capacity is less than 5kw and whether the battery's minimum temperature is less than -10°C. If yes, proceed to step S3.2; otherwise, proceed to step S3.3; Step S3.2, battery low temperature protection; Step S3.21, determine whether the APU is started in REV mode or other modes, if yes, proceed to step S3.22, if no, repeat this step; Step S3.23, executing battery low temperature protection; Step S3.24, VCU constantly requests APU to generate 5kW of power; Step S3.3, determine whether the battery's continuous charging capacity is higher than 10kW, or whether the battery's minimum temperature is higher than -8°C. If yes, proceed to step S3.4. If no, repeat this step. Step S3.4: Do not perform battery low temperature protection.

[0022] Step S4, battery discharge limit calibration, the specific contents are: Step S4.1, determine whether the driving mode is EV, if yes, proceed to step S4.2, if no, proceed to step S4.3; Step S4.2, when SOC is lower than 16%, the available power of the battery starts to be reduced linearly, and when SOC is 10%, it drops to 0; Step S4.3, the driving mode is SHEV; Step S4.4, when S0C is lower than 18%, the available power of the battery starts to decrease linearly, and drops to 0 at 12%.

[0023] Step S5, electric drive external characteristic limit calibration, the specific content is: Step S5.1, driving mode is ECO; Step S5.11, determine whether the speed is lower than the base speed, if yes, proceed to step S5.12. If no, proceed to step S5.13; Step S5.12: No external characteristic limitation is performed below the motor base speed; Step S5.13, the external characteristic torque limit makes the drive power output less than or equal to 90KW; Step S5.2, the driving mode is Normal; Step S5.21, determine whether the speed is lower than the base speed, if yes, proceed to step S5.22. If no, proceed to step S5.23; Step S5.22: No external characteristic limitation is performed below the motor base speed; Step S5.23, the external characteristic torque limit makes the drive power output less than or equal to 110KW.

[0024] It should be noted that when the ambient temperature is low in winter and the driver has a heating request and presses the heating switch, the air conditioning control panel CLM will forward the heating request to the vehicle control unit (hereinafter referred to as "VCU") of EVCAN through the central gateway TBOX. After the VCU receives the CLM heating request forwarded by TBOX, the intervention driving mode cannot enter the pure electric EV mode. The mode management module determines that the engine needs to be started. The VCU sends an engine start instruction to the range extender (hereinafter referred to as "APU") control unit GCU. The GCU then interacts with the engine control unit (hereinafter referred to as "EMS") to control the engine start. After the engine starts and runs, the cooling water temperature increases to provide a heating source for the passenger compartment. In different driving modes, after the engine is started due to a heating request, different control strategies are adopted for the APU power generation control. If the engine is started due to a heating request intervention in the EV mode or the extended range mode (hereinafter referred to as "REV"), the APU power generation control adopts a control strategy that allows the user to freely select the APU power generation power. The default power generation power only supports the power consumption of high-voltage accessories (initial calibration 1kW). In this way, if the battery power is high, the engine is only used to provide heat source for vehicle heating. At the same time, the low-power power generation ensures that the engine does not consume more fuel and does not consume electricity when in the power generation state. The reason why the APU is allowed to generate electricity at a low power instead of idling is that when the engine is idling, the engine output torque is zero. The generator needs to consume some electrical energy to maintain speed control with the synchronous speed. Therefore, the APU needs to generate electricity at a low power to meet the heating needs of the passenger compartment without increasing excessive fuel consumption or consuming battery power.

[0025] If a heating request intervenes and the engine is started in the intelligent mode (hereinafter referred to as "Auto"), then according to the definition of the intelligent mode, the VCU will automatically calculate the APU power generation request after the engine is started. When the battery power is high, the default low-power power generation strategy is adopted to allow the battery to fully discharge. When the battery SOC is lower than 25%, in order to ensure the power and power balance of the whole vehicle, the APU will enter power following control, that is, the APU power generation power follows the discharge demand power of the drive end, the power consumption of the high-voltage accessories and the battery replenishment demand power.

[0026] It should be noted that when there is a heating request in different driving modes, the VCU will control the start of the engine to provide warm air heat source for the passenger compartment. The driving mode changes due to the intervention of the heating request. However, in order to avoid the driver's confusion about the driving mode, when entering heating in different modes, the driving mode before entering heating is calibrated, and the target driving mode cannot be switched by clicking the driving mode switch during heating. After the heating request is exited, the driving mode before heating is maintained, and the user can switch the driving mode freely.

[0027] If the vehicle has no heating request, then for the EV mode, the battery SOC lower limit calibration of its mode conversion needs to be further lowered, and the EV mode exit discharge lower limit is calibrated to 16%. When the battery SOC is lower than 16%, the vehicle will exit the EV mode and enter the SHEV mode. In the SHEV mode, the VCU will control the engine to start, and the APU will perform power generation according to the VCU's energy management strategy.

[0028] When the APU starts to generate electricity, the battery SOC will gradually increase. When the battery SOC is calibrated to be higher than 18%, the vehicle will enter EV mode again. The purpose is to keep the battery power at a reasonable level, neither too low to cause the risk of power out of control or affect the power of the vehicle, nor too high to increase fuel consumption and affect the economy of the user.

[0029] For REV mode, an energy management strategy is adopted in which users independently select power generation. At the same time, appropriate restrictions are placed on the power requested from the APU to prevent overcharging of the battery and excessive NVH noise. For some battery platform products, the driving charging map is consistent with the plug-in charging map to ensure that the battery can be fully charged. The problem is that at 100% SOC, the external charging capacity of the battery management unit BMS is still greater than zero. For energy management control of the VCU, when the SOC is calibrated to be above 98%, the APU power demand is set to zero to avoid overcharging the battery due to charging when the battery is fully charged.

[0030] For Auto mode, when the battery SOC is higher than 30%, the actual EV mode is maintained, that is, when the battery power is high, in Auto mode, the battery is allowed to discharge independently, and the engine is prohibited from intervening to avoid fuel consumption and increase the user's vehicle cost. The battery remaining power judgment threshold obtained by looking up the table based on vehicle speed and SOC is calibrated to -1000, so that the available remaining power of the battery above 30% SOC is always less than the EV conversion threshold, so that the engine will not start when the SOC is higher than the threshold of 30% in Auto mode.

[0031] When the calibrated battery SOC is lower than 25%, the engine is started at an appropriate time according to the driving power demand and SOC status. If the driving power demand is higher than the battery discharge capacity, or the SOC in Auto mode is lower than the calibrated threshold, the VCU will send a start command to the GCU, and the APU will start to generate electricity to power the vehicle drive.

[0032] In Auto mode, if the calibrated battery SOC is higher than 20% and the driving power demand is lower than the threshold, the EV mode is maintained; if the calibrated battery SOC is lower than 18%, the EV mode is exited and the SHEV mode is entered; The full-load mass of the large-power range extender is larger than that of the low-power range extender, and the driving power demand on the drive end is also greater. For the basic power conservation map for battery conservation, it is necessary to adaptably increase the power conservation power. For the battery conservation map for coasting and neutral gear, they are all adaptively increased by 5~10kW to replenish the battery faster and meet the power consumption required for large driving power. For the basic battery conservation map in driving state, they are all adaptively increased by 10~20kW to replenish the battery faster and meet the power consumption required for large driving power. The battery conservation map increment for neutral gear and coasting is smaller than the battery conservation map increment for driving. The purpose is to take into account the NVH of the whole vehicle. When coasting or in N gear, the wind noise is small and there is no driving power demand. Therefore, the power generation power of the APU does not need to be too large at this time. In the driving state, the required driving power itself is large, so the battery needs to be recharged faster so that the battery power can be better balanced; For extended-range electric vehicles, due to the presence of the APU, when the battery temperature is low in the cold winter, the battery charging capacity is low or charging is not allowed. When the driver releases the accelerator to let the vehicle coast or brakes to recover energy, the APU power reduction is slow, resulting in the energy recovery power being established, and the APU power generation power that does not decrease quickly is superimposed, causing the battery to be overcharged. Therefore, when the calibrated battery temperature is lower than 10°C and the battery charging capacity is lower than 5kW, the battery low temperature protection strategy is entered. After entering, the default APU power generation power is calibrated to 5kW to meet the basic high-voltage accessory power demand and battery heating mode power demand. When the calibrated battery temperature is higher than -8°C, or the battery charging capacity is higher than 10kW, the battery low temperature protection strategy is exited; In order to protect the battery life, the lower discharge limit of the battery is set according to the EV mode and SHEV mode. The lower discharge limit of the EV mode is further lowered, and the battery SOC is calibrated to not allow discharge at all to protect the battery. The battery allowable discharge power is linearly reduced from 16%. For the SHEV mode, the battery discharge power is limited from SOC18%, and the battery discharge power is allowed to drop to 0 at 12% to protect the battery. For the economy of the whole vehicle, it is necessary to adaptively restrict the external characteristics of the motor. On the premise of ensuring that the power requirements of most normal user driving conditions are covered, appropriate restrictions are placed on the external characteristics of the motor to improve the economy of the whole vehicle and maximize user benefits.

[0033] Regarding the external characteristic restrictions of the motor, the power of the whole vehicle needs to be guaranteed in the constant torque range, and the power of the whole vehicle needs to meet the vehicle climbing requirements under extreme working conditions such as heavy-load climbing steep slopes. Above the motor inflection point, the external characteristics of the motor need to be gradually restricted to ensure that the driving power demand of the motor is generally lower than the power limit upper limit allowed for the electric drive.

[0034] The maximum external characteristic power limit in the calibrated ECO mode is 90kW, and the maximum external characteristic power limit in the calibrated Normal mode is 110kW. The ECO mode has good economy, and the Normal mode has strong power. In order to ensure the low-speed climbing power of the whole vehicle, it is necessary to pay attention to fully releasing the peak torque capacity of the motor in the constant torque range. When approaching the motor base speed, the motor enters the constant power range and begins to gradually limit the external characteristic torque capacity of the motor to limit the maximum driving power output of the motor; When the battery temperature is extremely low in winter, the battery thermal management system has not yet brought the battery temperature back to a comfortable working temperature when the cold car is just started, and the battery charging capacity is very weak or even zero. At this time, in order to save battery power and ensure that the vehicle has more available power to the electric drive system for vehicle driving, the VCU will control the start of the APU to generate electricity, calibrate energy recovery first, and APU power generation second. When the electric braking power increases, the VCU dynamically adjusts the APU's allowable power generation power in real time according to the battery's available charging power to ensure that the battery will not be overcharged under dynamic conditions, which not only ensures braking efficiency and braking performance, reduces mechanical brake wear, but also protects the battery.

[0035] For the REV mode, since it allows users to freely select the power generation, when the low ambient temperature in winter greatly reduces the battery charging capacity, it is prohibited to enter the REV mode to prevent the power generation selected by the user in the REV mode from approaching the battery charging capacity boundary. When the driving to non-driving condition causes the battery to overcharge and the calibrated battery charging capacity is lower than 55kW, it is prohibited to enter the REV mode. When the calibrated battery charging capacity is higher than 60kW, entering the REV mode allows users to freely select the power generation. The upper and lower limits of the calibration threshold are set according to the charging map capability of the large-capacity battery and the power consumption of the driving end.

[0036] When the temperature is low in winter, the battery's discharge capacity will also decrease due to its physical properties. If the ambient temperature is extremely low and the battery's discharge capacity is very low after the vehicle is started in a cold state, the power of the entire vehicle will be greatly reduced. When the calibrated battery's discharge capacity is lower than 35kW, the VCU will immediately control the APU to start generating electricity, providing more available discharge power for the electric drive to improve the power of the entire vehicle.

[0037] The present invention is described above by way of example in conjunction with the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-mentioned method. As long as various non-substantial improvements are made using the method concept and technical solution of the present invention; or the above-mentioned concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. A calibration method for a large-capacity extended-range electric vehicle, characterized in that: The overall calibration framework includes drive mode calibration, energy management calibration, battery low temperature protection calibration, battery discharge limit calibration and electric drive external characteristic limit calibration; The specific calibration method is as follows: Step S1, driving mode calibration. When there is a heating request in different driving modes, the VCU will control the engine to start to provide a warm air heat source for the passenger compartment. The driving mode is changed due to the intervention of the heating request. However, in order to avoid the driver's confusion about the driving mode, when entering the heating mode in different calibration modes, the driving mode before entering the heating mode is maintained, and the target driving mode cannot be switched by clicking the driving mode switch during heating. Step S2, energy management calibration. The full-load mass of the large-power range extender is larger than that of the low-power range extender, and the driving power demand on the driving end is also greater. For the basic power conservation map of battery conservation, it is necessary to adaptively increase the power conservation power. For the battery conservation map of coasting and neutral gear, the power conservation power is adaptively increased by 5~10kW to replenish the battery faster and meet the power consumption of the large driving power demand. Step S3, battery low temperature protection calibration. For extended-range electric vehicles, due to the presence of the APU, when the battery temperature is low in the cold state in winter, the battery charging capacity is low or charging is not allowed. When the driver releases the accelerator to let the vehicle coast or brakes to recover energy, the APU power reduction is slow, resulting in the energy recovery power being established, and the APU power generation power that does not decrease rapidly is superimposed, causing the battery to be overcharged. Therefore, when the battery temperature is calibrated to be lower than 10°C and the battery charging capacity is lower than 5kW, the battery low temperature protection strategy is entered; Step S4, battery discharge limit calibration. In order to protect the battery life, the battery discharge lower limit is set according to the EV mode and the SHEV mode. The EV mode discharge lower limit is further lowered. Step S5, electric drive external characteristic limit calibration, in order to ensure the low-speed climbing dynamics of the whole vehicle, it is necessary to pay attention to releasing all the peak torque capacity of the motor in the constant torque range. When approaching the motor base speed, the motor enters the constant power range and begins to gradually limit the external characteristic torque capacity of the motor to limit the maximum driving power output of the motor.

2. A method for calibrating a large-capacity extended-range electric vehicle according to claim 1, characterized in that: The step S1, driving mode calibration, comprises the following specific steps: Step S1.1, determine whether there is a heating request, if yes, proceed to step S1.2, if no, proceed to step S1.3; Step S1.2, the external driving mode remains in the pre-heating driving mode; Step S1.3, after the heating request is exited, the driving mode before heating is maintained, and the user is allowed to switch the driving mode freely; Step S1.4, determining whether the driver has pressed the driving mode switch, if so, proceed to step S1.5, if not, repeat this step; Step S1.5: the driving mode remains in the pre-heating driving mode.

3. A method for calibrating a large-capacity extended-range electric vehicle according to claim 2, characterized in that: The specific content of step S1.3 is: Step S1.31, determine whether the SOC in EV mode is lower than 16% or lower than 18% in SHEV mode, or whether the battery discharge capacity is lower than 35kW. If yes, proceed to step S1.32; otherwise, proceed to step S1.33; Step S1.32, VCU controls the engine to start; Step S1.33, determine whether the battery continuous charging capacity is higher than 60kw, if yes, proceed to step S1.34, if no, proceed to step S1.35; Step S1.34, allowing entry into REV mode; Step S1.35, determine whether the continuous charging capacity is less than 55kw, if yes, proceed to step S1.36, if no, proceed to step S1.37; Step S1.36, prohibiting entry into REV mode; Step S1.37, keep the driving mode unchanged.

4. A calibration method for a large-capacity extended-range electric vehicle according to claim 1, characterized in that: The step S2, energy management calibration, includes the following specific steps: Step S2.1, determine whether the driving mode is REV or EV mode and there is a heating request, if so, proceed to step S2.

2. If not, proceed to step S2.3; Step S2.2, the user selects the power generation; Step S2.21, determine whether the battery SOC is greater than or equal to 98%, if so, proceed to step S2.22, if not, proceed to step S2.23; Step S2.24, requesting the power generation to be zero; Step S2.25, generating electricity according to the power selected by the user; Step S2.3, determine whether the driving mode is Auto, if so, proceed to step S2.4; Step S2.4, determine whether the battery SOC is higher than 30%, if yes, proceed to step S2.5, if no, proceed to step S2.6; Step S2.5, keep the battery discharged and prohibit starting the APU to generate electricity; Step S2.6, determine whether the battery SOC is lower than 25%, if so, proceed to step S2.7, if not, repeat this step; Step S2.7, APU power following control; Step S2.8, the basic map of battery power conservation for coasting and braking is all adaptable and marked up by 5~10KW; Step S2.9, the battery power conservation basic map adaptability of the driving condition is increased by 10~20kW.

5. A calibration method for a large-capacity extended-range electric vehicle according to claim 1, characterized in that: The step S3, battery low temperature protection calibration, specifically includes: Step S3.1, determine whether the battery's continuous charging capacity is less than 5kw and whether the battery's minimum temperature is less than -10°C. If yes, proceed to step S3.2; otherwise, proceed to step S3.3; Step S3.2, battery low temperature protection; Step S3.21, determine whether the APU is started in REV mode or other modes, if yes, proceed to step S3.22, if no, repeat this step; Step S3.23, executing battery low temperature protection; Step S3.24, VCU constantly requests APU to generate 5kW of power; Step S3.3, determine whether the battery's continuous charging capacity is higher than 10kW, or whether the battery's minimum temperature is higher than -8°C. If yes, proceed to step S3.

4. If no, repeat this step. Step S3.4: Do not perform battery low temperature protection.

6. A method for calibrating a large-capacity extended-range electric vehicle according to claim 1, characterized in that: The step S4, battery discharge limit calibration, specifically includes: Step S4.1, determine whether the driving mode is EV, if yes, proceed to step S4.2, if no, proceed to step S4.3; Step S4.2, when SOC is lower than 16%, the available power of the battery starts to be reduced linearly, and when SOC is 10%, it drops to 0; Step S4.3, the driving mode is SHEV; Step S4.4, when S0C is lower than 18%, the available power of the battery starts to decrease linearly, and drops to 0 at 12%.

7. A method for calibrating a large-capacity extended-range electric vehicle according to claim 1, characterized in that: The step S5, electric drive external characteristic limit calibration, specifically includes: Step S5.1, driving mode is ECO; Step S5.11, determine whether the speed is lower than the base speed, if yes, proceed to step S5.

12. If no, proceed to step S5.13; Step S5.12: No external characteristic limitation is performed below the motor base speed; Step S5.13, the external characteristic torque limit makes the drive power output less than or equal to 90KW; Step S5.2, the driving mode is Normal; Step S5.21, determine whether the speed is lower than the base speed, if yes, proceed to step S5.

22. If no, proceed to step S5.23; Step S5.22: No external characteristic limitation is performed below the motor base speed; Step S5.23, the external characteristic torque limit makes the drive power output less than or equal to 110KW.

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