Vehicle electric quantity maintaining method based on actual driving working condition of user
By estimating the vehicle mass and calculating the ramp angle of the hybrid vehicle system, the generator power generation power is re-determined, which solves the problem of low SOC and insufficient power under the actual driving conditions of the user, and achieves more efficient energy utilization and more reliable power performance.
Patent Information
- Application Number
- CN202411961578.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-30
- Publication Date
- 2025-03-18
AI Technical Summary
The existing hybrid vehicle systems are difficult to automatically adjust the power capacity under the actual driving conditions of users, resulting in low SOC and limited power of the power battery, resulting in insufficient power of the vehicle.
Through vehicle mass estimation and ramp angle calculation, the generator power generation power is re-determined to adapt to the actual driving conditions of users, especially in heavy-load low-speed climbing and heavy-load high-speed climbing conditions to compensate for the ramp power generation.
It effectively avoids the power supply in the user's working conditions, improves the power performance of the vehicle, extends the battery life, improves the energy utilization efficiency, and enhances the reliability and adaptability of the vehicle.
Smart Images
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Abstract
Description
Technical Field
[0001] The invention relates to the technical field of hybrid vehicle design and development, and in particular to a vehicle power maintenance method based on actual driving conditions of users. Background Art
[0002] At present, light commercial vehicles with hybrid architecture all adopt a hybrid system control strategy based on rule control, which includes:
[0003] The actual working mode of the vehicle is determined according to the hybrid architecture of the vehicle. The working modes of the power-split hybrid architecture include pure electric mode (EV), hybrid mode (HEV), and direct drive mode (DV). When the remaining capacity (SOC) of the vehicle battery is lower than the calibration value or the required power of the vehicle is higher than the calibration value, the engine starts and enters the hybrid mode. The generator calculates the power generation according to the difference between the current SOC and the target SOC. When the vehicle speed meets the direct drive requirements, the engine enters the direct drive mode. If the architecture meets the requirements, the drive motor can meet the power generation requirements.
[0004] Because the vehicle control strategy is pre-calibrated and set during the development process, in order to ensure that the actual comprehensive fuel consumption of users is low, the power charged from the power grid is used first, and the target SOC of the vehicle balance is low. The target SOC cannot be automatically adjusted according to the actual working conditions of users. Because the load weight of commercial vehicle users varies greatly, and the actual driving conditions of different users vary greatly, it is very easy for the user's working condition power to remain at a low level, resulting in insufficient power of the vehicle due to insufficient SOC and limited discharge power of the power battery. Summary of the invention
[0005] In order to overcome the shortcomings of the above-mentioned technology, the purpose of the present invention is to provide a vehicle power maintenance method based on the user's actual driving conditions, so as to be suitable for the user's actual usage conditions and avoid the user's operating condition power being maintained at a low level, resulting in insufficient power of the whole vehicle due to insufficient SOC and limited discharge power of the power battery.
[0006] To achieve the above purpose, the technical solution adopted by the present invention is as follows:
[0007] A method for maintaining vehicle power based on actual driving conditions of a user, wherein the vehicle adopts a hybrid architecture, and the method is special in that the method comprises the following steps:
[0008] 1) Vehicle mass estimation;
[0009] 2) When the vehicle runs onto a ramp, the angle of the current ramp is calculated based on the vehicle mass;
[0010] 3) Redetermine the generator power generation capacity based on the actual working condition of the vehicle on the slope.
[0011] Furthermore, the vehicle is a light commercial vehicle adopting a power-split hybrid architecture.
[0012] Furthermore, the step 1) includes: obtaining the estimated mass of the vehicle according to the following formula:
[0013]
[0014] Where: m is the vehicle mass; T e is the powertrain output torque; i fd is the main reduction ratio; i g is the gearbox ratio; η is the transmission system efficiency; r is the tire rolling radius; C d is the vehicle drag coefficient; A is the frontal area; v is the current vehicle speed; f is the road resistance coefficient; δ is the vehicle rotation mass conversion coefficient; a is the vehicle acceleration at the current moment, which can be obtained by the following formula:
[0015]
[0016] Where: v t is the current vehicle speed, v t-1 is the vehicle speed at the previous moment, and dt is the time step.
[0017] Furthermore, step 1) further includes estimating the vehicle mass at multiple moments when the vehicle speed is not 0 within a set distance, and processing the calculation results by weighted average method; the set distance is not less than 1000 meters. By taking the average value through multiple calculations, the accuracy of mass estimation can be improved.
[0018] As a preferred solution, the vehicle mass estimation in step 1) includes estimation during the vehicle starting process. Since the torque required during the vehicle starting process is large and the mass does not change during the start-up, the estimation accuracy is high. It is preferred to estimate the mass during the vehicle starting process.
[0019] Furthermore, the vehicle mass estimation in step 1) includes estimating when the vehicle starts on a flat road; the method for judging whether the starting process is on a flat road includes: after the vehicle is ignited and started, the motor speed at the moment when the brake and accelerator are not pressed is used as the basis for judging whether it is on a slope. If the motor speed is zero, it is judged that the vehicle is on a flat road. Because commercial vehicles generally do not load or unload on ramps, if the vehicle starts on a ramp, the estimated mass of the vehicle at the last flat road start can be used as the current estimated mass of the vehicle. Because the total weight of commercial vehicles is large, when the vehicle is parked on a ramp without pressing the accelerator or brake, the motor has a momentary speed opposite to the gear position. If the instantaneous motor speed is 0, it is judged that the vehicle is on a flat road.
[0020] As a preferred solution, step 2) includes: when the vehicle drives onto a ramp, calculating the angle of the ramp; the ramp angle is obtained according to the following formula:
[0021]
[0022] Where α is the ramp angle.
[0023] Furthermore, step 2) further includes: calculating the average of the slope angles at multiple times when the vehicle speed is not 0 within a set distance on the slope as the current slope reference angle; the set distance is not less than 100 meters. By calculating the average value multiple times, the accuracy of the slope angle calculation can be improved.
[0024] As a preferred solution, the actual working conditions in step 3) include heavy-load low-speed climbing and heavy-load high-speed climbing.
[0025] Furthermore, the heavy load means that the vehicle mass exceeds 50% of the rated load of the vehicle; the low-speed climbing speed is no more than 30km / h; the high-speed climbing speed is no less than 90km / h. The high power demand of light commercial vehicles is mainly in heavy load / overload, high and low speed climbing conditions.
[0026] Furthermore, when it is identified that the current working condition is a heavy-load low-speed climbing condition, the new target power generation of the generator is recalculated to perform slope power generation compensation; when it is identified that the slope angle is negative and the vehicle is in a downhill condition, the initial power generation is restored; the initial power generation is the initial target power generation calibrated for the vehicle; the calculation formula for the new target power generation is as follows:
[0027]
[0028] Where: P target is the new target power generation; P ini is the initial power generation. When the vehicle is in a heavy-loaded, low-speed climbing condition, the original power generation of the vehicle may not meet the power maintenance requirements, and slope power generation compensation is required to compensate the power generation.
[0029] Furthermore, when it is recognized that the current condition is a heavy-load high-speed climbing condition, the SOC required to be reserved for the actual climbing distance of the vehicle is calculated; when it is recognized that the slope angle is negative and the vehicle is in a downhill condition, the SOC is restored to the vehicle's calibrated target SOC. Due to the large total weight of commercial vehicles, it is difficult for the high-speed extreme climbing hybrid assembly to meet the compensation power demand. In order to ensure that the vehicle has sufficient climbing power, the power battery needs to be compensated SOC in advance to avoid insufficient battery output kilometers due to power loss during climbing, resulting in the vehicle slowing down.
[0030] Furthermore, the set distance is 1 to 5 kilometers.
[0031] Furthermore, the calculation formula for the SOC that needs to be reserved for the actual climbing distance of the vehicle is as follows:
[0032] SOC targetnew=SOC target +Ene / Bat capacity ;
[0033] in:
[0034]
[0035] Where: Ene is the energy required to maintain the set climbing distance; SOC targetnew Calculate the current target SOC; SOC target Bat is the original calibration target SOC; capacity is the rated capacity of the battery; Distance represents the set distance.
[0036] Furthermore, the method for determining the high-speed working condition includes: when the average vehicle speed within the set time is greater than or equal to the set value, and the radiator fan power is less than the average power within the low speed period or the steering wheel angle acceleration is less than the average value within the low speed period, it is determined that the current vehicle is in the high-speed working condition. The set value is not less than 90km / h; the set time is 3 to 5 minutes; the low speed period is the period when the vehicle speed does not exceed 30km / h during driving.
[0037] A vehicle controller is special in that it includes a vehicle power maintenance unit for executing the above-mentioned vehicle power maintenance method based on the actual driving condition of the user.
[0038] Compared with the prior art, the present invention has the following beneficial effects:
[0039] The present invention provides a vehicle power maintenance method based on the user's actual driving conditions, which is suitable for the user's actual driving conditions and avoids the user's operating condition power being maintained at a low level, resulting in insufficient vehicle power due to insufficient SOC and limited discharge power of the power battery. It can improve the user's driving experience, extend battery life, improve energy utilization efficiency, and enhance vehicle reliability and adaptability.
[0040] The present invention first identifies the road state of the vehicle when it starts driving. If the vehicle is on a straight road, the reference mass when the vehicle speed is not 0 is calculated based on the powertrain output torque, the transmission system speed ratio, the vehicle wind rolling resistance coefficient and the windward area, and then the current road ramp angle of the vehicle is calculated in real time based on the reference mass. When the vehicle is in a low-speed climbing state, the required compensation power generation of the vehicle is calculated based on the calculated mass and the ramp angle. In order to avoid the situation where the vehicle loses power and slows down due to high-speed climbing, when the vehicle recognizes the high-speed working condition, the vehicle calculates the SOC value that needs to be increased for extreme climbing and updates the power to maintain the target SOC to ensure the power of the vehicle. DETAILED DESCRIPTION
[0041] In order to better explain the present invention, the main contents of the present invention are further explained below in conjunction with specific embodiments, but the contents of the present invention are not limited to the following embodiments.
[0042] The present invention provides a vehicle power maintenance method based on actual driving conditions of a user, wherein the vehicle is a light commercial vehicle using a power split hybrid architecture, and comprises the following steps:
[0043] 1) Vehicle mass estimation: The estimation is performed after the vehicle has traveled a set distance during the start-up process.
[0044] 1.1) Determine whether the vehicle is on a flat road during the start process. If the vehicle is not on a flat road, use the vehicle mass calculated in the last trip. If the vehicle is on a flat road, proceed to step 1.2).
[0045] After the vehicle is ignited and started, the motor speed at the moment when the brake and accelerator are not pressed is used as the basis for judging whether it is on a slope. If the motor speed is zero, the vehicle is judged to be on a flat road. Because the torque required during the vehicle starting process is large, and the mass will not change during the start-up, the estimation accuracy is high, and the mass is estimated during the vehicle starting process. Because the total weight of commercial vehicles is large, when the accelerator and brake are not pressed when parked on a slope, the motor has a momentary speed opposite to the gear position. If the instantaneous motor speed is 0, the vehicle is judged to be on a flat road.
[0046] 1.2) Obtain the estimated vehicle mass when the vehicle speed is not 0 during the start process according to the following formula:
[0047]
[0048] Where: m is the vehicle mass, T e is the powertrain output torque; i fd is the main reduction ratio, i g is the gearbox ratio, η is the transmission system efficiency, r is the tire rolling radius; C d is the vehicle drag coefficient, A is the frontal area, v is the current vehicle speed, f is the road resistance coefficient, δ is the vehicle rotation mass conversion coefficient; a is the vehicle acceleration at the current moment, which can be obtained by the following formula:
[0049]
[0050] Where: v t is the current vehicle speed, v t-1 is the vehicle speed at the previous moment, and dt is the time step.
[0051] The vehicle mass is estimated at multiple moments when the vehicle speed is not 0 within a set distance during the starting process, and the calculation results are processed by weighted average method; the set distance during the starting process is not less than 1000 meters.
[0052] 2) When the vehicle is on a slope, the angle of the slope is calculated based on the vehicle mass.
[0053] When the vehicle drives onto a ramp, after driving a set distance on the ramp, the angle of the ramp is calculated, and the average value of the ramp angle at multiple moments when the vehicle speed is not 0 within the set distance on the ramp is calculated as the current ramp reference angle; the set distance on the ramp is not less than 100 meters.
[0054] The slope is obtained according to the following formula:
[0055]
[0056] Where α is the ramp angle.
[0057] 3) Redetermine the generator power generation capacity based on the actual working condition of the vehicle on the slope.
[0058] The actual working conditions include heavy-loaded low-speed climbing and heavy-loaded high-speed climbing; heavy-load means the vehicle mass exceeds 50% of the rated load of the vehicle; the speed of low-speed climbing is no more than 30km / h; the speed of high-speed climbing is no less than 90km / h. The high power demand of light commercial vehicles is mainly in heavy-loaded / overloaded, high-speed and low-speed climbing conditions.
[0059] The specific method is as follows:
[0060] a. When it is identified that the current working condition is heavy-load and low-speed climbing, the new target power generation of the generator is recalculated to compensate for the slope power generation; when it is identified that the slope angle is negative and the vehicle is in a downhill working condition, the initial power generation is restored; the initial power generation is the initial target power generation calibrated for the vehicle; the calculation formula of the new target power generation is as follows:
[0061]
[0062] Where: P target is the new target power generation; P ini is the initial power generation. When the vehicle is in a heavy-loaded, low-speed climbing condition, the original power generation of the vehicle may not meet the power maintenance requirements, and slope power generation compensation is required to compensate the power generation.
[0063] b. When it is recognized that the current condition is a heavy-load high-speed climbing condition, the SOC required to be reserved for the actual climbing distance of the vehicle is calculated; when it is recognized that the slope angle is negative and the vehicle is in a downhill condition, the SOC target is restored to the vehicle's calibrated target SOC. The set distance on the slope is 1 to 5 kilometers, preferably 5 kilometers. Due to the large total weight of commercial vehicles, it is difficult for high-speed extreme climbing hybrid assemblies to meet the compensation power demand. In order to ensure that the vehicle has sufficient climbing power, the power battery needs to be compensated SOC in advance to avoid insufficient battery output kilometers due to power loss during climbing, resulting in vehicle deceleration.
[0064] The method for determining the high-speed working condition includes: when the average vehicle speed of the whole vehicle is ≥90km / h within 3 to 5 minutes, and the radiator fan power is less than the average power in the low-speed period or the steering wheel angle acceleration is less than the average value in the low-speed period, it is determined that the current whole vehicle is in the high-speed working condition. The low-speed period is a period when the vehicle speed does not exceed 30km / h during the driving process.
[0065] The calculation formula for the SOC that needs to be reserved for the actual climbing distance of the vehicle is as follows:
[0066] SOC targetnew =SOC target +Ene / Bat capacity ;
[0067] in:
[0068]
[0069] Where: Ene is the energy required to maintain the set distance climbing, SOC targetnew The current target SOC is calculated, SOC target The target SOC for the original calibration of the vehicle; Bat capacity is the rated capacity of the battery; Distance represents the set distance.
[0070] This specific embodiment also provides a vehicle controller, including a vehicle power maintenance unit, which is used to execute the above-mentioned vehicle power maintenance method based on the actual driving condition of the user.
[0071] The above-mentioned vehicle power maintenance method performs real-time calculations through the vehicle power maintenance unit to obtain the target power generation power or SOC corresponding to the current vehicle load, slope angle, and vehicle speed. If the current operating condition is heavy-load low-speed climbing and heavy-load high-speed climbing, the generator is controlled to generate power for slope power generation compensation or SOC. When the ramp angle is zero or a negative value, it is restored to the vehicle calibration parameters.
[0072] The present invention identifies the road state of the vehicle when it starts driving. For example, if the vehicle is on a straight road, the reference mass when the vehicle speed is not 0 is calculated based on the powertrain output torque, the transmission system speed ratio, the vehicle wind rolling resistance coefficient and the windward area, and then the current road ramp angle of the vehicle is calculated in real time based on the reference mass. When the vehicle is climbing a slope at a low speed, the required compensation power generation of the vehicle is calculated based on the calculated mass and the ramp angle. In order to avoid the situation where the vehicle loses power during high-speed climbing and causes a deceleration, when the vehicle identifies a high-speed operating condition, the vehicle calculates the limit climbing and needs to increase the SOC value and update the power to maintain the target SOC to ensure the power of the vehicle. The present invention avoids the situation where the power of the user's operating condition is maintained at a low level, resulting in insufficient power of the vehicle due to insufficient SOC and limited discharge power of the power battery.
[0073] Other parts not described belong to the prior art.
Claims
1. A vehicle power maintenance method based on actual driving conditions of a user, wherein the vehicle adopts a hybrid architecture, and is characterized by: The following steps are involved: 1) Vehicle mass estimation; 2) When the vehicle runs onto a ramp, the angle of the current ramp is calculated based on the vehicle mass; 3) Redetermine the generator power generation capacity based on the actual working condition of the vehicle on the slope.
2. The vehicle power maintenance method according to claim 1, characterized in that: The vehicle is a light commercial vehicle using a power-split hybrid architecture.
3. The vehicle power maintenance method according to claim 2, characterized in that: The step 1) includes: obtaining the estimated mass of the vehicle according to the following formula: Where: m is the vehicle mass, T e is the powertrain output torque; i fd is the main reduction ratio, i g is the gearbox ratio, η is the transmission system efficiency, r is the tire rolling radius; C d is the vehicle drag coefficient, A is the frontal area, v is the current vehicle speed, f is the road resistance coefficient, δ is the vehicle rotation mass conversion coefficient; a is the vehicle acceleration at the current moment, which can be obtained by the following formula: Where: v t is the current vehicle speed, v t-1 is the vehicle speed at the previous moment, and dt is the time step.
4. The vehicle power maintenance method according to claim 3, characterized in that: Step 1) also includes estimating the vehicle mass at multiple moments when the vehicle speed is not 0 within a set distance, and processing the calculation results by weighted average method; the set distance is not less than 1000 meters.
5. The vehicle power maintenance method according to claim 4, characterized in that: In step 1), the vehicle mass estimation is performed during the vehicle starting process.
6. The vehicle power maintenance method according to claim 5, characterized in that: In step 1), the vehicle mass estimation is performed when starting on a flat road; the method for judging whether the starting process is on a flat road includes: after the vehicle is ignited and started, the motor speed at the moment when the brake and accelerator are not pressed is used as the basis for judging whether it is on a slope; if the motor speed is zero, it is judged that the vehicle is on a flat road.
7. The vehicle power maintenance method according to claim 6, characterized in that: Step 2) includes: when the vehicle drives onto a ramp, calculating the angle of the ramp; the ramp angle is obtained according to the following formula: Where α is the ramp angle.
8. The vehicle power maintenance method according to any one of claims 1 to 7, characterized in that: Step 2) also includes: calculating the average slope angle at multiple moments when the vehicle speed is not 0 within a set distance on the slope as the current slope reference angle; the set distance is not less than 100 meters.
9. The vehicle power maintenance method according to claim 8, characterized in that: The actual working conditions in step 3) include heavy-load low-speed climbing and heavy-load high-speed climbing; When it is recognized that the current working condition is heavy-load and low-speed climbing, the new target power generation of the generator is recalculated to compensate for the slope power generation; when it is recognized that the slope angle is negative and the vehicle is in a downhill working condition, the initial power generation is restored; the initial power generation is the initial target power generation calibrated for the vehicle; the calculation formula of the new target power generation is as follows: Where: P target is the new target power generation; P ini is the initial power generation; When it is recognized that the current condition is a heavy-load high-speed climbing condition, the SOC required to be reserved for the actual climbing distance of the vehicle is calculated; when it is recognized that the slope angle is negative and the vehicle is in a downhill condition, the SOC target is restored to the vehicle calibrated target SOC; the calculation formula for the SOC required to be reserved for the actual climbing distance of the vehicle is as follows: SOCIETY targetnew =SOC target +Ene / Bat capacity ; in: Where: Ene is the energy required to maintain the set distance climbing, SOC targetnew The current target SOC is calculated, SOC target Bat is the original calibration target SOC; capacity is the rated capacity of the battery; Distance represents the set distance.
10. A vehicle controller, characterized in that: It includes a vehicle power maintenance unit, which is used to execute the vehicle power maintenance method based on the user's actual driving conditions as described in any one of claims 1 to 9.