Hybrid electric vehicle control method

Abstract

The invention provides a hybrid electric vehicle control method which comprises the steps that whether a vehicle enters an overcharge risk working condition or not is judged, if the vehicle enters the overcharge risk working condition, overcharge risk control is executed, if the condition for quitting the overcharge risk control is met, if the condition is not met, the overcharge risk control continues to be executed, and if the condition is met, the overcharge risk control is stopped. And if not, exiting the overcharge risk control. According to the hybrid electric vehicle control method, the overcharge risk working condition in the driving process of the hybrid electric vehicle is effectively recognized by analyzing the vehicle driving parameters and the driver intention, the overcharge risk is reduced by adjusting the vehicle running state under the condition that driving is not affected, the differential requirements under different driving working conditions are met, and the driving safety is improved. Safety risk is reduced and power battery life is prolonged.

Description

Technical Field

[0001] The present disclosure relates to the technical field of hybrid electric vehicles, and in particular to a control method for a hybrid electric vehicle. Background Art

[0002] With the rapid development of the hybrid vehicle market, there are more and more hybrid products. In order to improve the economy and power of hybrid strategies, the system's demand for power assistance or charging is usually judged based on the power battery status, and then a torque or speed command is issued to adjust the engine, generator motor and drive motor operating point to achieve effective control of power assistance or charging. By issuing a torque command to the engine, a speed or torque command to the generator to control the engine speed, and a torque command to the drive motor, the engine needs to burn to provide torque, so there is a certain response delay. The torque response delay of the diesel engine is more obvious than that of the gasoline engine. When the engine's high power demand decreases in a short period of time, the control accuracy decreases, and it is very easy to cause the power battery to overcharge, increase safety risks, and reduce battery life. Summary of the invention

[0003] The purpose of the present disclosure is to provide a hybrid vehicle control method that can solve one or more of the above-mentioned prior art problems.

[0004] The present disclosure provides a hybrid vehicle control method, comprising:

[0005] Step 1: Determine whether the vehicle enters an overcharging risk condition. If the vehicle enters an overcharging risk condition, execute step 2;

[0006] Step 2: Perform overcharge risk control,

[0007] Step 3: Determine whether the conditions for exiting overcharge risk control are met. If not, proceed to step 2. If met, proceed to step 4.

[0008] Step 4: Exit overcharge risk control and return to step 1.

[0009] In some embodiments, in step 1, determining whether the vehicle enters an overcharging risk condition includes:

[0010] Step 1.1: Determine whether the vehicle is currently in a driving state. If the vehicle is in a driving state, execute step 1.2. If the vehicle is not in a driving state, determine that the vehicle has not entered an overcharging risk condition.

[0011] Step 1.2: Determine whether the battery is in a charging state. If the battery is in a charging state, execute step 1.3. If the battery is not in a charging state, determine that the vehicle has not entered an overcharging risk condition.

[0012] Step 1.3: Determine whether the current driver has a torque reduction demand. If the current driver has a torque reduction demand, execute step 1.4. If the current driver does not have a torque reduction demand, determine that the vehicle has not entered an overcharging risk condition.

[0013] Step 1.4: Determine whether there is a current charging demand. If there is a current charging demand, execute step 1.5. If there is no current charging demand, determine that the vehicle has not entered an overcharging risk condition.

[0014] Step 1.5: Determine whether the engine torque response is delayed. If the engine torque response is delayed, execute step 1.6. If the engine torque response is not delayed, determine that the vehicle has not entered an overcharging risk condition.

[0015] Step 1.6: Determine whether there is a battery overcharging trend at present. If so, determine that the vehicle has entered an overcharging risk condition. If not, determine that the vehicle has not entered an overcharging risk condition.

[0016] In some implementations, in step 1.1, determining whether the vehicle is currently in a driving state includes:

[0017] The current gear position and speed of the vehicle are obtained. When the vehicle is currently in the driving gear position and the speed is greater than a set first threshold, it is determined that the vehicle is currently in a driving state; otherwise, it is determined that the vehicle is not currently in a driving state.

[0018] In some implementations, in step 1.2, determining whether the battery is in a charging state includes:

[0019] The current engine power and the actual power of the power battery are obtained. When the engine power is greater than a set second threshold and the actual power of the power battery is less than a set third threshold, it is determined that the battery is in a charging state; otherwise, it is determined that the battery is not in a charging state.

[0020] In some implementations, in step 1.3, determining whether the current driver has a torque reduction demand includes:

[0021] The current vehicle speed and accelerator pedal opening are obtained, and the driving demand torque is obtained according to the vehicle speed and the accelerator pedal opening. When the driving demand torque is greater than the set fourth threshold, the driving demand torque is reduced, and the driving demand torque change rate is greater than the set fifth threshold, it is determined that the current driver has a demand for reducing torque; otherwise, it is determined that the current driver does not have a demand for reducing torque.

[0022] In some implementations, in step 1.4, determining whether there is a current charging demand includes:

[0023] A power battery SOC signal is obtained. When the power battery SOC is lower than a set sixth threshold, it is determined that there is a current charging demand; otherwise, it is determined that there is no current charging demand.

[0024] In some embodiments, in step 1.5, determining whether the engine torque response is delayed includes:

[0025] The current actual engine torque and the engine demand torque are obtained. When the engine demand torque decreases, the engine demand torque change rate is greater than the set seventh threshold, and the difference between the actual engine torque and the engine demand torque is always greater than the set eighth threshold within a preset first time period, it is determined that the engine torque response is delayed; otherwise, it is determined that the engine torque response is not delayed.

[0026] In some implementations, in step 1.6, determining whether there is a battery overcharging trend currently includes:

[0027] The real-time current, real-time voltage and allowable charging power of the power battery are obtained, and the real-time power of the power battery is calculated according to the current and voltage of the power battery. When the real-time power of the power battery is less than the allowable charging power of the power battery, the difference between the allowable charging power of the power battery and the real-time power of the power battery is less than the set ninth threshold value, and the change rate of the real-time power of the power battery is greater than the set tenth threshold value, it is determined that there is a battery overcharging trend at present; otherwise, it is determined that there is no battery overcharging trend at present.

[0028] In some embodiments, in step 2, overcharge risk control includes:

[0029] Step 2.1: Send a speed command to the generator, and correct the target speed based on the difference between the real-time power of the power battery and the allowable charging power of the power battery pool;

[0030] Step 2.2: Send a torque command to the generator, and at the same time, based on the difference between the real-time power of the power battery and the allowable charging power of the power battery pool, correct the engine demand torque reduction gradient.

[0031] In some implementations, in step 3, determining whether a condition for exiting overcharge risk control is met includes:

[0032] Step 3.1: Obtain the current engine power and the actual power of the power battery. When the engine power is less than the set first power value and the actual power of the power battery is less than the set second power value, it is determined that the conditions for exiting the overcharge risk control are met, otherwise, execute step 3.2;

[0033] Step 3.2: Obtain the driving demand torque. When the driving demand torque is less than the set first torque value and the driving demand torque decrease change rate is less than the set first change rate, it is determined that the condition for exiting the overcharge risk control is met, otherwise, execute step 3.3;

[0034] Step 3.3: Obtain the duration of the vehicle entering the overcharging risk condition. When the duration of the vehicle entering the overcharging risk condition exceeds the set first time value, determine that the conditions for exiting the overcharging risk control are met, otherwise return to execute step 3.1.

[0035] The hybrid vehicle control method provided by the present disclosure can effectively identify overcharging risk conditions during the driving of the hybrid vehicle by analyzing vehicle driving parameters and driver intentions, and can reduce overcharging risks by adjusting the vehicle operating status without affecting driving, thereby meeting differentiated needs under different driving conditions, reducing safety risks, and extending the life of the power battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0037] Figure 1 A flowchart of a hybrid vehicle control method provided by an embodiment of the present disclosure. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solution and advantages of the embodiments of the present disclosure clearer, the technical solution in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0039] Example:

[0040] In this embodiment, refer to the attached manual Figure 1 , provides a hybrid vehicle control method, the method specifically comprising the following steps:

[0041] Step 1: Determine whether the vehicle enters an overcharging risk condition. If the vehicle enters an overcharging risk condition, execute step 2;

[0042] Step 2: Perform overcharge risk control,

[0043] Step 3: Determine whether the conditions for exiting overcharge risk control are met. If not, proceed to step 2. If met, proceed to step 4.

[0044] Step 4: Exit overcharge risk control and return to step 1.

[0045] In an optional embodiment, in step 1, determining whether the vehicle enters an overcharging risk condition may include the following steps:

[0046] Step 1.1: Determine whether the vehicle is currently in a driving state. If the vehicle is in a driving state, execute step 1.2. If the vehicle is not in a driving state, determine that the vehicle has not entered an overcharging risk condition.

[0047] Step 1.2: Determine whether the battery is in a charging state. If the battery is in a charging state, execute step 1.3. If the battery is not in a charging state, determine that the vehicle has not entered an overcharging risk condition.

[0048] Step 1.3: Determine whether the current driver has a torque reduction demand. If the current driver has a torque reduction demand, execute step 1.4. If the current driver does not have a torque reduction demand, determine that the vehicle has not entered an overcharging risk condition.

[0049] Step 1.4: Determine whether there is a current charging demand. If there is a current charging demand, execute step 1.5. If there is no current charging demand, determine that the vehicle has not entered an overcharging risk condition.

[0050] Step 1.5: Determine whether the engine torque response is delayed. If the engine torque response is delayed, execute step 1.6. If the engine torque response is not delayed, determine that the vehicle has not entered an overcharging risk condition.

[0051] Step 1.6: Determine whether there is a battery overcharging trend at present. If so, determine that the vehicle has entered an overcharging risk condition. If not, determine that the vehicle has not entered an overcharging risk condition.

[0052] In step 1.1, determining whether the vehicle is currently in a driving state may include:

[0053] The current gear position and speed of the vehicle are obtained. When the vehicle is currently in the driving gear position and the speed is greater than a set first threshold, it is determined that the vehicle is currently in a driving state, otherwise it is determined that the vehicle is currently not in a driving state. The vehicle gear position and speed can be directly read from the vehicle control system.

[0054] In step 1.2, determining whether the battery is in a charging state may include:

[0055] The current engine power and the actual power of the power battery are obtained. When the engine power is greater than the set second threshold and the actual power of the power battery is less than the set third threshold, it is determined that the battery is in a charging state, otherwise it is determined that the battery is not in a charging state. Among them, the actual power of the power battery can be calculated by multiplying the actual current of the power battery and the actual voltage of the power battery. The engine power, the actual current of the power battery and the actual voltage of the power battery can be directly read from the control system of the vehicle.

[0056] In step 1.3, determining whether the current driver has a torque reduction demand includes:

[0057] The current vehicle speed and accelerator pedal opening are obtained, and the driving demand torque is obtained according to the vehicle speed and the accelerator pedal opening. When the driving demand torque is greater than the set fourth threshold value, the driving demand torque is reduced, and the driving demand torque change rate is greater than the set fifth threshold value, it is determined that the current driver has a torque reduction demand, otherwise it is determined that the current driver does not have a torque reduction demand. Among them, the vehicle speed and accelerator pedal opening can be directly read from the vehicle control system. Under normal circumstances, when the vehicle leaves the factory, the control system will pre-store a table of the corresponding relationship between the vehicle speed and the accelerator pedal opening and the driving demand torque. By looking up the table, the driving demand torque can be obtained according to the vehicle speed and the accelerator pedal opening. The current driving demand torque is compared with the driving demand torque corresponding to the vehicle speed and the accelerator pedal opening at the previous moment to determine whether the driving demand torque is reduced, and the amount of the driving demand torque change per unit time is calculated as the driving demand torque change rate. In this way, the intention of the current driver is judged to meet the different driving needs of the driver.

[0058] In step 1.4, determining whether there is a current charging demand includes:

[0059] The power battery SOC signal is obtained, and when the power battery SOC is lower than a set sixth threshold, it is determined that there is a current charging demand, otherwise it is determined that there is no current charging demand. The power battery SOC signal can be directly read from the vehicle control system.

[0060] In step 1.5, determining whether the engine torque response is delayed includes:

[0061] The current actual engine torque and the engine demand torque are obtained. When the engine demand torque decreases, the engine demand torque change rate is greater than the set seventh threshold value, and the difference between the actual engine torque and the engine demand torque is always greater than the set eighth threshold value within the preset first time period, it is determined that the engine torque response is delayed, otherwise it is determined that the engine torque response is not delayed. Among them, the current actual engine torque and the engine demand torque can be directly obtained, and the current engine demand torque is compared with the engine demand torque obtained at the last moment to obtain whether the engine demand torque increases, decreases or remains unchanged, and the engine demand torque change per unit time is calculated as the engine demand torque change rate.

[0062] In step 1.6, determining whether there is a battery overcharge trend currently includes:

[0063] The real-time current, real-time voltage and allowable charging power of the power battery are obtained, and the real-time power of the power battery is calculated according to the current and voltage of the power battery. When the real-time power of the power battery is less than the allowable charging power of the power battery, the difference between the allowable charging power of the power battery and the real-time power of the power battery is less than the set ninth threshold, and the rate of change of the real-time power of the power battery is greater than the set tenth threshold, it is determined that there is a battery overcharge trend at present, otherwise it is determined that there is no battery overcharge trend at present. Among them, the real-time current, real-time voltage and allowable charging power of the power battery can all be directly obtained from the vehicle control system.

[0064] In step 2, overcharge risk control includes:

[0065] Step 2.1: Send a speed command to the generator, and correct the target speed based on the difference between the real-time power of the power battery and the allowed charging power of the power battery pool. The target speed is obtained by analyzing the initial energy management system of the vehicle. The target speed of each vehicle is different according to the initial energy management system and vehicle parameters, but the target speed is a parameter that can be directly obtained by the vehicle.

[0066] The correction strategy for the target speed is as follows: if the difference between the real-time power of the power battery and the allowable charging power of the power battery is lower than the first preset value, the target speed is increased, thereby increasing the discharge power. The larger the absolute value of the difference between the difference and the first preset value, the more the target speed is increased. If the difference between the real-time power of the power battery and the allowable charging power of the power battery is not lower than the preset value, the target speed is reduced, thereby reducing the discharge power. The larger the absolute value of the difference between the difference and the first preset value, the more the target speed is reduced. The specific adjustment ratio can be set according to the actual parameters of the vehicle.

[0067] Step 2.2: Send a torque command to the generator to increase the engine torque drop gradient to achieve rapid torque unloading. At the same time, based on the difference between the real-time power of the power battery and the allowed charging power of the power battery pool, the increase in the engine torque drop gradient is corrected. The engine torque drop gradient can be directly obtained from the vehicle control system.

[0068] The correction strategy for the increase in the engine demand torque decrease gradient is to calculate the difference between the real-time power of the power battery and the allowable charging power of the power battery. The difference between the real-time power of the power battery and the allowable charging power of the power battery is inversely proportional to the increase in the engine demand torque decrease gradient. That is, the greater the difference between the real-time power of the power battery and the allowable charging power of the power battery, the less the increase in the engine demand torque decrease gradient, thereby maintaining a larger power generation power. The smaller the difference between the real-time power of the power battery and the allowable charging power of the power battery, the more the engine demand torque decrease gradient increases, which can reduce the risk of overcharging the power battery.

[0069] In step 3, determining whether the conditions for exiting overcharge risk control are met includes:

[0070] Step 3.1: Obtain the current engine power and the actual power of the power battery. When the engine power is less than the set first power value and the actual power of the power battery is less than the set second power value, it is determined that the conditions for exiting the overcharge risk control are met, otherwise, execute step 3.2;

[0071] Step 3.2: Obtain the driving demand torque. When the driving demand torque is less than the set first torque value and the driving demand torque decrease change rate is less than the set first change rate, it is determined that the condition for exiting the overcharge risk control is met, otherwise, execute step 3.3;

[0072] Step 3.3: Obtain the duration of the vehicle entering the overcharging risk condition. When the duration of the vehicle entering the overcharging risk condition exceeds the set first time value, determine that the conditions for exiting the overcharging risk control are met, otherwise return to execute step 3.1.

[0073] In this way, the overcharging risk can be dealt with without affecting the driving performance of the vehicle, avoiding the impact of being in the overcharging risk condition for a long time on driving. At the same time, when the overcharging risk disappears, the vehicle can return to normal driving state in time.

[0074] The hybrid vehicle control method provided by the present disclosure can effectively identify overcharging risk conditions during the driving of the hybrid vehicle by analyzing vehicle driving parameters and driver intentions, avoid battery overcharging caused by engine response lag, reduce overcharging risks by adjusting the vehicle operating state without affecting driving, meet differentiated needs under different driving conditions, reduce safety risks, and extend the life of the power battery.

[0075] The above sequence of the embodiments of this specification is for description only and does not represent the advantages and disadvantages of the embodiments. And the above describes specific embodiments of the specification. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recorded in the claims can be performed in an order different from that in the embodiments and still achieve the desired results. In addition, the processes depicted in the drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0076] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0077] A person skilled in the art will understand that all or part of the steps to implement the above embodiments may be accomplished by hardware or by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, and the above-mentioned storage medium may be a read-only memory, a disk or an optical disk, etc.

[0078] The above are only preferred embodiments of the present disclosure and are not intended to limit the present disclosure. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present disclosure should be included in the protection scope of the present disclosure.

Claims

1. A hybrid vehicle control method, characterized in that: include: Step 1: Determine whether the vehicle enters an overcharging risk condition. If the vehicle enters an overcharging risk condition, execute step 2; Step 2: Perform overcharge risk control, Step 3: Determine whether the conditions for exiting overcharge risk control are met. If not, proceed to step 2. If met, proceed to step 4. Step 4: Exit overcharge risk control and return to step 1.

2. The hybrid vehicle control method according to claim 1, characterized in that: In step 1, determining whether the vehicle enters an overcharging risk condition includes: Step 1.1: Determine whether the vehicle is currently in a driving state. If the vehicle is in a driving state, execute step 1.

2. If the vehicle is not in a driving state, determine that the vehicle has not entered an overcharging risk condition. Step 1.2: Determine whether the battery is in a charging state. If the battery is in a charging state, execute step 1.

3. If the battery is not in a charging state, determine that the vehicle has not entered an overcharging risk condition. Step 1.3: Determine whether the current driver has a torque reduction demand. If the current driver has a torque reduction demand, execute step 1.

4. If the current driver does not have a torque reduction demand, determine that the vehicle has not entered an overcharging risk condition. Step 1.4: Determine whether there is a current charging demand. If there is a current charging demand, execute step 1.

5. If there is no current charging demand, determine that the vehicle has not entered an overcharging risk condition. Step 1.5: Determine whether the engine torque response is delayed. If the engine torque response is delayed, execute step 1.

6. If the engine torque response is not delayed, determine that the vehicle has not entered an overcharging risk condition. Step 1.6: Determine whether there is a battery overcharging trend at present. If so, determine that the vehicle has entered an overcharging risk condition. If not, determine that the vehicle has not entered an overcharging risk condition.

3. The hybrid vehicle control method according to claim 2, characterized in that: In step 1.1, determining whether the vehicle is currently in a driving state includes: The current gear position and speed of the vehicle are obtained. When the vehicle is currently in the driving gear position and the speed is greater than a set first threshold, it is determined that the vehicle is currently in a driving state; otherwise, it is determined that the vehicle is not currently in a driving state.

4. The hybrid vehicle control method according to claim 2, characterized in that: In step 1.2, determining whether the battery is in a charging state includes: The current engine power and the actual power of the power battery are obtained. When the engine power is greater than a set second threshold and the actual power of the power battery is less than a set third threshold, it is determined that the battery is in a charging state; otherwise, it is determined that the battery is not in a charging state.

5. The hybrid vehicle control method according to claim 2, characterized in that: In step 1.3, determining whether the current driver has a torque reduction demand includes: The current vehicle speed and accelerator pedal opening are obtained, and the driving demand torque is obtained according to the vehicle speed and the accelerator pedal opening. When the driving demand torque is greater than the set fourth threshold, the driving demand torque is reduced, and the driving demand torque change rate is greater than the set fifth threshold, it is determined that the current driver has a demand for reducing torque; otherwise, it is determined that the current driver does not have a demand for reducing torque.

6. The hybrid vehicle control method according to claim 2, characterized in that: In step 1.4, determining whether there is a current charging demand includes: A power battery SOC signal is obtained. When the power battery SOC is lower than a set sixth threshold, it is determined that there is a current charging demand; otherwise, it is determined that there is no current charging demand.

7. The hybrid vehicle control method according to claim 2, characterized in that: In step 1.5, determining whether the engine torque response is delayed includes: The current actual engine torque and the engine demand torque are obtained. When the engine demand torque decreases, the engine demand torque change rate is greater than the set seventh threshold, and the difference between the actual engine torque and the engine demand torque is always greater than the set eighth threshold within a preset first time period, it is determined that the engine torque response is delayed; otherwise, it is determined that the engine torque response is not delayed.

8. The hybrid vehicle control method according to claim 2, characterized in that: In step 1.6, determining whether there is a battery overcharge trend currently includes: The real-time current, real-time voltage and allowable charging power of the power battery are obtained, and the real-time power of the power battery is calculated according to the current and voltage of the power battery. When the real-time power of the power battery is less than the allowable charging power of the power battery, the difference between the allowable charging power of the power battery and the real-time power of the power battery is less than the set ninth threshold value, and the change rate of the real-time power of the power battery is greater than the set tenth threshold value, it is determined that there is a battery overcharging trend at present; otherwise, it is determined that there is no battery overcharging trend at present.

9. The hybrid vehicle control method according to claim 1, characterized in that: In step 2, overcharge risk control includes: Step 2.1: Send a speed command to the generator, and correct the target speed based on the difference between the real-time power of the power battery and the allowable charging power of the power battery pool; Step 2.2: Send a torque command to the generator, and at the same time, based on the difference between the real-time power of the power battery and the allowable charging power of the power battery pool, correct the engine demand torque reduction gradient.

10. The hybrid vehicle control method according to claim 1, characterized in that: In step 3, determining whether the conditions for exiting overcharge risk control are met includes: Step 3.1: Obtain the current engine power and the actual power of the power battery. When the engine power is less than the set first power value and the actual power of the power battery is less than the set second power value, it is determined that the conditions for exiting the overcharge risk control are met, otherwise, execute step 3.2; Step 3.2: Obtain the driving demand torque. When the driving demand torque is less than the set first torque value and the driving demand torque decrease change rate is less than the set first change rate, it is determined that the condition for exiting the overcharge risk control is met, otherwise, execute step 3.3; Step 3.3: Obtain the duration of the vehicle entering the overcharging risk condition. When the duration of the vehicle entering the overcharging risk condition exceeds the set first time value, determine that the conditions for exiting the overcharging risk control are met, otherwise return to execute step 3.1.

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