Hybrid electric vehicle range extender power generation power control method, system and vehicle

Abstract

The application discloses a kind of hybrid electric vehicle range extender power generation power control method and system.The method comprises: determining final target battery state parameter based on ambient temperature, slope and vehicle speed;According to the deviation of target and actual parameter, actual parameter and slope, the power generation intensity is calculated and the maximum value is taken as a coefficient;Determine engine comfort speed limit value in combination with vehicle speed, accelerator pedal;Determine the final power generation power based on the optimal economic line, limit value and demand power;Further determine engine speed and torque.The method can comprehensively adjust the power generation intensity based on SOC deviation, actual state and road conditions, balance power preservation demand and battery discharge capacity, control the range extender to run in the economic zone under the premise of considering comfort and power preservation performance, and improve the economy of the vehicle.The application also discloses a vehicle.

Description

Technical Field

[0001] This invention belongs to the field of automotive technology. Specifically, this invention relates to a method, system, and vehicle for controlling the power generation of a hybrid electric vehicle range extender. Background Technology

[0002] With the diversification of demand for range-extended hybrid vehicles, it is necessary to reduce overall vehicle energy consumption while ensuring comfort and battery power. The instantaneous fuel consumption of the range extender directly reflects the energy conversion efficiency, but in daily operation, there is a significant contradiction between comfort and energy economy.

[0003] In urban low-speed conditions, in order to meet comfort requirements, the range extender is forced to operate at low speed, resulting in a significant decrease in combustion efficiency.

[0004] Under heavy load conditions such as mountainous areas or highway overtaking, the engine speed cannot be increased due to comfort limitations, causing it to deviate from the economic zone, resulting in excessive torque, or insufficient power generation causing the battery to continuously deplete. Summary of the Invention

[0005] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention provides a method for controlling the power generation of a hybrid electric vehicle range extender, with the goal of rationally controlling the range extender to operate within its economic zone while balancing comfort and battery power retention performance, thereby improving fuel economy.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a method for controlling the power generation of a hybrid electric vehicle range extender, comprising: Determine the final target battery state parameters; The first power generation intensity is determined based on the deviation between the final target battery state parameters and the actual battery state parameters. The second power generation intensity is determined based on the actual battery state parameters. The third power generation intensity is determined based on the road slope. The maximum value of the first power generation intensity, the second power generation intensity and the third power generation intensity is taken as the final power generation intensity coefficient. The engine comfort speed limit is determined based on vehicle speed, accelerator pedal signal, and final power generation intensity coefficient. Based on the optimal economic line of the range extender, the engine comfort speed limit, the power generation spectrum and the power demand of the whole vehicle, the final power generation of the range extender is determined. The engine speed is determined based on the final range extender power output and the optimal economic line of the range extender, and the engine torque is determined based on the engine speed and the final range extender power output, so as to determine the engine operating condition point.

[0007] Obtain the target battery state parameters, set multiple target battery state parameters based on different operating conditions, and take the maximum value as the final target battery state parameter.

[0008] The acquisition of target battery state parameters includes: setting a first target battery state parameter based on ambient temperature, setting a second target battery state parameter based on road slope, setting a third target battery state parameter based on vehicle speed, and taking the maximum value of the first target battery state parameter, the second target battery state parameter, and the third target battery state parameter as the final target battery state parameter.

[0009] The determination of the final power generation intensity coefficient includes: the greater the absolute value of the deviation between the final target battery state parameter and the actual battery state parameter, the greater the first power generation intensity setting; the greater the actual battery state parameter or the higher the battery temperature, the smaller the second power generation intensity setting; the greater the road slope, the greater the third power generation intensity setting.

[0010] The determination of the final range extender power output includes: when the vehicle's required power output is less than the maximum value of the power output spectrum corresponding to the maximum power output intensity, power is generated using the power output spectrum; when the vehicle's required power output is greater than the maximum value of the power output spectrum corresponding to the maximum power output intensity, power is generated using the vehicle's required power output.

[0011] The hybrid electric vehicle range extender power generation control method further includes: setting a start threshold and a stop threshold based on the target battery state parameters and vehicle speed; when the actual battery state parameters are greater than the start threshold, the engine starts and operates according to the engine operating condition point; when the actual battery state parameters are less than the stop threshold, the engine stops.

[0012] The present invention also provides a power generation control system for a hybrid electric vehicle range extender, comprising: The first acquisition module is configured to acquire target battery state parameters, set multiple target battery state parameters based on different operating conditions, and take the maximum value as the final target battery state parameter. The first determining module is configured to determine the first power generation intensity based on the deviation between the final target battery state parameters and the actual battery state parameters, determine the second power generation intensity based on the actual battery state parameters, determine the third power generation intensity based on the road slope, and take the maximum value as the final power generation intensity coefficient. The second acquisition module is configured to acquire the engine comfort speed limit, set the basic comfort speed limit based on vehicle speed and accelerator pedal signal, and determine the corresponding comfort speed limit in combination with the final power generation intensity coefficient. The second determining module is configured to obtain the range extender's power generation, determine the power generation spectrum under different power generation intensities based on the range extender's optimal economic line and the corresponding comfort speed limit, compare the power generation spectrum corresponding to the maximum power generation intensity with the vehicle's required power, and determine the final range extender's power generation. The third determining module is configured to determine the engine speed based on the final range extender power generation and the optimal economic line of the range extender, and to determine the engine torque based on the engine speed and the final range extender power generation, so as to determine the engine operating condition point.

[0013] The first acquisition module is configured to: set a first target battery state parameter based on ambient temperature, set a second target battery state parameter based on road slope, set a third target battery state parameter based on vehicle speed, and take the maximum value of the first target battery state parameter, the second target battery state parameter, and the third target battery state parameter as the final target battery state parameter.

[0014] The first determining module is configured such that: the greater the absolute value of the deviation between the final target battery state parameter and the actual battery state parameter, the greater the first power generation intensity setting; the greater the actual battery state parameter or the higher the battery temperature, the smaller the second power generation intensity setting; and the greater the road slope, the greater the third power generation intensity setting.

[0015] The second determining module is configured to generate electricity using the power generation spectrum when the vehicle's required power is less than the maximum value of the power generation spectrum corresponding to the maximum power generation intensity; and to generate electricity using the vehicle's required power when the vehicle's required power is greater than the maximum value of the power generation spectrum corresponding to the maximum power generation intensity, subject to the power generation capacity of the range extender hardware.

[0016] The range extender power generation control system further includes a start-stop control module, configured to set start-up and stop-up thresholds based on the target battery state parameters and vehicle speed; when the actual battery state parameters are greater than the start-up threshold, the engine starts and operates according to the engine operating condition point; when the actual battery state parameters are less than the stop-up threshold, the engine stops.

[0017] The range extender power generation control system also includes a vehicle power demand acquisition module, which is configured to calculate the vehicle power demand based on vehicle speed, acceleration, gradient, accelerator pedal, and vehicle electrical power consumption.

[0018] The range extender power generation control system also includes an optimal economic line acquisition module, which is configured to calculate the optimal economic line of the range extender based on the principle of the lowest specific fuel consumption under the same power, according to the engine fuel consumption map and the generator efficiency map.

[0019] The present invention also provides a vehicle including the range extender power generation control system.

[0020] The hybrid electric vehicle range extender power generation control method of the present invention dynamically calculates the power generation intensity coefficient by comprehensively considering the SOC deviation, actual SOC, and gradient. It can adaptively adjust the power generation intensity according to the actual battery state and external road conditions, dynamically balance the power supply demand and battery discharge capacity, and set a comfort speed limit based on vehicle speed and accelerator pedal, combined with the power generation intensity coefficient. This allows for reasonable control of the range extender to operate in the economic zone while taking into account both comfort and battery power supply performance, thereby improving economy. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the process for obtaining the power generation intensity coefficient in an embodiment of the present invention; Figure 2 This is a schematic diagram of the process for obtaining the power generated by the range extender in an embodiment of the present invention. Detailed Implementation

[0022] To make the technical problems, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention. In the following embodiments, "target battery state parameter" corresponds to the target SOC (State of Charge, or SOC for short), "actual battery state parameter" corresponds to the actual SOC, "engine comfort speed limit" corresponds to the engine NVH (noise, vibration, and harshness) speed limit, and "power generation map" corresponds to the power generation map.

[0023] Furthermore, in the following embodiments, the terms "first," "second," and "third" do not represent an absolute distinction in structure and / or function, nor do they represent a sequential execution order; they are merely for the convenience of description.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly associated with those skilled in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments and is not intended to limit the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0025] The technical concept of this invention includes: Range-extended hybrid electric vehicles (REEVs) are increasingly favored by consumers due to their longer driving range and better driving experience. With the increasing diversification of market demands, further reducing overall vehicle energy consumption while ensuring driving comfort and battery charging capacity has become an important direction for the development of REEV technology. The instantaneous fuel consumption of the range extender system is one of the key indicators for measuring the energy consumption level of REEVs, directly reflecting the energy conversion efficiency of the vehicle under different operating conditions. However, in the actual operation of REEVs, there is often a significant contradiction between driving comfort and energy economy. Specifically, in urban driving conditions, vehicles are usually in a low-speed and frequently start-stop operating mode, with relatively low overall power demand. At this time, if the range extender is forced to operate in a low-speed range to meet the vehicle's NVH (noise, vibration, and harshness) and other comfort requirements, it will lead to a significant decrease in engine combustion efficiency, preventing it from operating in the high-efficiency economic zone. Furthermore, this contradiction is further exacerbated under high-load conditions such as mountain driving or high-speed overtaking. Under such operating conditions, the vehicle requires the range extender to provide higher power generation to meet the power demand. However, due to the requirements of overall vehicle comfort, the increase in engine speed is strictly limited. This forces the engine to increase torque to output power, causing the engine operating conditions to deviate significantly from the efficient and economical range, resulting in a sharp increase in fuel consumption. Alternatively, the limited power generation of the range extender may fail to meet the power demand of the entire vehicle, leading to continuous depletion of the power battery and a deterioration in the vehicle's battery retention performance. Therefore, existing range extender control strategies for range-extended hybrid vehicles still have significant shortcomings in coordinating driving comfort, battery retention capacity, and energy economy. Existing control logic makes it difficult to ensure that the range extender always operates in the efficient and economical range under various complex operating conditions, resulting in generally high vehicle fuel consumption and poor battery retention performance under specific conditions. The technical solution of this invention is as follows: Firstly, such as Figure 1 and Figure 2 As shown, this embodiment of the invention provides a method for controlling the power generation of a hybrid electric vehicle range extender, including the following steps: S100, Determine the final target battery state parameters; S200. Determine the first power generation intensity based on the deviation between the final target battery state parameters and the actual battery state parameters, determine the second power generation intensity based on the actual battery state parameters, determine the third power generation intensity based on the road slope, and take the maximum value of the first power generation intensity, the second power generation intensity and the third power generation intensity as the final power generation intensity coefficient. S300 determines the engine comfort speed limit based on vehicle speed, accelerator pedal signal and final power generation intensity coefficient; S400, based on the optimal economic line of the range extender, the engine comfort speed limit, the power generation spectrum and the power demand of the whole vehicle, the final power generation of the range extender is determined; S500 determines the engine speed based on the final range extender power output and the optimal economic line of the range extender, and determines the engine torque based on the engine speed and the final range extender power output, in order to determine the engine operating condition point.

[0026] Specifically, the hybrid electric vehicle range extender power generation control method provided in this embodiment of the invention can be executed by the vehicle control unit (VCU). Before executing the control method of this embodiment, a joint simulation model is first built based on basic automotive theory. This model includes a control model, a vehicle powertrain physical model, and a range extender physical model. The vehicle powertrain physical model includes a power battery physical model, the range extender physical model includes an engine physical model and a generator physical model, and the control model includes a vehicle control model and a range extender control model. The signals of these three modules interact with each other. Based on this joint simulation model, various parameters during the operation of the hybrid electric vehicle can be acquired and calculated in real time, providing the necessary data for the execution of subsequent control strategies.

[0027] In step S100 above, target battery state parameters are obtained, multiple target battery state parameters are set according to different operating conditions, and the maximum value is taken as the final target battery state parameter.

[0028] Furthermore, in step S100 above, obtaining the target battery state parameters specifically includes: setting a first target battery state parameter based on ambient temperature, setting a second target battery state parameter based on road slope, setting a third target battery state parameter based on vehicle speed, and taking the maximum value of the first target battery state parameter, the second target battery state parameter, and the third target battery state parameter as the final target battery state parameter.

[0029] In actual operation, hybrid electric vehicles (HEVs) operate under complex and varied conditions, making it difficult to meet the needs of all scenarios with a single target battery state value. For example, in scenarios such as highways or mountain roads, HEVs require strong power output. In these cases, a larger target battery state parameter is defined to ensure that the HEV's power battery has a strong discharge capacity, thereby meeting the power requirements of the HEV. Conversely, in low-speed, flat road scenarios, a lower target battery state parameter is defined. This not only increases the pure electric range but also reduces frequent engine start-stop cycles, avoiding the problem of high fuel consumption caused by the engine operating in a low-speed, low-efficiency range for extended periods. By setting target values ​​for multiple operating scenarios, such as ambient temperature, road gradient, and vehicle speed, and taking the maximum value as the final target battery state parameter, the resulting target battery state parameter comprehensively covers the needs of multiple scenarios, preventing or significantly mitigating the occurrence of vehicle battery depletion from the outset.

[0030] as Figure 1 shown, the specific process of the above step S200 is as follows: First, signals such as an actual battery state parameter (actual SOC) and cell temperature are acquired from a physical power battery model. A deviation δ is calculated according to the final target battery state parameter acquired in the foregoing step and the actual battery state parameter SOC , specifically, the deviation δ SOC = actual SOC - target SOC. Multiple levels of first power generation intensity are set according to the magnitude of the deviation δ SOC , and the specific setting is as follows: the larger the absolute value of the deviation between the final target battery state parameter and the actual battery state parameter, the larger the set first power generation intensity. That is, the larger the deviation is, it indicates that the current electric quantity of the power battery deviates more from the target value, and the range extender needs to provide higher power generation intensity to quickly supplement the electric quantity of the power battery.

[0031] In the embodiment of the present invention, as Figure 1 shown, the first power generation intensity is set with three levels, namely a1, a2 and a3, and a1 < a2 < a3. When the deviation is less than a first electric quantity preset threshold, the first power generation intensity is defined as a1. In this state, the actual battery state parameter is relatively close to the final target battery state parameter, the electric quantity gap of the power battery is small, and only the lower power generation intensity a1 needs to be set at this time. When the deviation is greater than or equal to the first electric quantity preset threshold and less than a second electric quantity preset threshold, the first power generation intensity is defined as a2. In this state, the actual electric quantity has deviated to a certain extent, and the system needs to accelerate the electric energy supplement of the power battery. At this time, the medium-intensity a2 is set, so that the range extender increases the power generation power, and promotes the electric quantity of the power battery to gradually rise back to a target interval. When the deviation is greater than or equal to the second electric quantity preset threshold, the first power generation intensity is defined as a3. In this state, the actual electric quantity seriously deviates from the target value, and the whole vehicle faces the risk of power preservation failure. At this time, the highest-intensity a3 is set, and the range extender will operate with the maximum possible power generation power under the maximum comfort rotation speed limit and hardware external characteristic limit allowed by the current working condition, so as to restore the electric quantity of the power battery to a safe target interval at the fastest speed.

[0032] Second, multiple levels of second power generation intensity are set according to the actual battery state parameter and the cell temperature signal of the power battery, and the specific setting is as follows: the larger the actual battery state parameter is or the higher the cell temperature is, the smaller the set second power generation intensity is. This is because when the actual SOC is larger or the cell temperature is higher, the discharge capacity of the power battery is stronger, at this time the demand for power generation of the range extender is relatively reduced, and the required power generation intensity is smaller.

[0033] In the embodiment of the present invention, as Figure 1As shown, the second power generation intensity is set in three levels, namely b1, b2 and b3, with b1 < b2 < b3. When the actual SOC is in a high range and the cell temperature is in the optimal discharge temperature range, the internal resistance of the power battery is small, and the power battery has strong charge and discharge throughput capacity. At this time, the second power generation intensity is defined as b1, the system allows the power battery to bear large power output, and the range extender can maintain a low power generation intensity, so as to maximize the economy of pure electric driving. When the actual SOC is in a medium range or the cell temperature slightly deviates from the optimal range (such as slightly low temperature or slightly high temperature), the discharge capacity of the power battery is limited to a certain extent. At this time, the second power generation intensity is defined as b2, and the range extender appropriately increases the power generation intensity. When the actual SOC is in a low range or the cell temperature is in an extreme range, the discharge capacity of the power battery is significantly attenuated and cannot meet the demand for high-power acceleration or climbing of the whole vehicle. At this time, the second power generation intensity is defined as b3, and the range extender needs to operate at a relatively high power generation intensity to avoid safety problems such as deep power depletion of the power battery or thermal runaway caused by over-discharge.

[0034] Then, multiple levels of third power generation intensity are set according to the road gradient, and the specific setting is as follows: the larger the road gradient of current driving, the larger the set third power generation intensity. Under climbing conditions, the power demand of the whole vehicle is large, and it is necessary to increase the power generation intensity to prevent the power of the power battery from dropping rapidly.

[0035] In the embodiment of the present invention, as Figure 1 shown, the second power generation intensity is set in three levels, namely c1, c2 and c3, with c1 < c2 < c3. When the road gradient is less than the first preset gradient threshold, the driving power demand of the whole vehicle is low, and it mainly overcomes rolling resistance and wind resistance. At this time, the third power generation intensity is defined as c1, and the range extender does not need to increase the power generation load, and only needs to maintain a low power generation intensity. When the road gradient is greater than or equal to the first preset gradient threshold and less than the second preset gradient threshold, the power demand of the whole vehicle increases. To prevent the power of the power battery from dropping rapidly during continuous climbing, the third power generation intensity is defined as c2 at this time, and the range extender intervenes in advance and increases the power generation intensity to output energy together with the power battery. When the road gradient is greater than or equal to the second preset gradient threshold, the whole vehicle is under a heavy load condition, and low-voltage protection will be triggered if only the power battery supplies power. At this time, the third power generation intensity is defined as c3, and the range extender outputs the maximum power generation power within the allowable range of hardware to slow down the attenuation rate of the power of the power battery to the greatest extent, and ensure the power performance and continuous climbing capability of the whole vehicle.

[0036] Finally, the maximum value among the first power generation intensity value 'a', the second power generation intensity value 'b', and the third power generation intensity value 'c' is taken to obtain the final range extender power generation intensity coefficients X1, X2, X3, etc. A larger value for the range extender power generation intensity coefficient indicates greater power generation intensity. By using the above maximum value logic, the required power generation intensity can be dynamically and accurately determined by comprehensively considering power deviation, the battery's own discharge capacity, and external road conditions and load, thus achieving a balance between power supply needs and battery discharge capacity.

[0037] like Figure 1 As shown, the maximum value logic in this embodiment of the invention specifically refers to the vehicle controller calculating the first, second, and third power generation intensities based on the battery level deviation, battery condition, and road gradient within the same control cycle. Then, it performs a maximum value operation, using the largest of these three values ​​as the final range extender power generation intensity coefficient for the current cycle. For example, when the vehicle is traveling on a flat road and the battery has sufficient charge, the values ​​of the first, second, and third power generation intensities may all be at a low level. After the maximum value operation, the system outputs a smaller final range extender power generation intensity coefficient, such as X1. In this case, the range extender maintains low-power generation or remains off to improve pure electric economy. When the vehicle suddenly enters a long, steep slope, although the battery charge has not yet decreased significantly in the initial stage and the battery itself is in good condition, the road load causes the third power generation intensity to increase sharply. Through the maximum value operation, the system immediately outputs a high power generation intensity coefficient, such as X3, controlling the range extender to operate and increasing power generation, effectively avoiding control lag and preventing a rapid decrease in battery charge. By adopting this maximum-value logic, the control system can comprehensively and dynamically determine the current power deviation, battery discharge capacity, and external road conditions, ensuring accurate energy distribution and achieving an effective balance between the vehicle's power supply needs and battery discharge capacity.

[0038] Those skilled in the art will understand that the number of the above-mentioned levels is not limited to three, and can be divided into more levels according to actual calibration needs.

[0039] like Figure 2 As shown, in step S300 above, the engine comfort speed limit is determined based on vehicle speed, accelerator pedal signal, and final power generation intensity coefficient. Specifically, the engine comfort speed limit is obtained, a basic comfort speed limit is set based on vehicle speed and accelerator pedal signal, and the corresponding comfort speed limit is determined in conjunction with the final power generation intensity coefficient. In practical applications, the lower the vehicle speed or the smaller the accelerator pedal position, the less external noise there is. In this case, to ensure overall vehicle ride comfort, the set basic comfort speed limit is smaller, limiting the engine speed increase. When the vehicle speed is higher or the accelerator pedal position is larger, tire noise or wind noise becomes the main noise source, which can mask some engine noise. In this case, the permissible engine comfort speed limit is higher.

[0040] Based on this, and combined with the previously determined final power generation intensity coefficient, corresponding engine comfort speed limits (Map1, Map2, Map3, etc.) are set for different levels of power generation intensity. The higher the power generation intensity, the higher the engine comfort speed limit, allowing the range extender to generate more power. This step, while ensuring overall vehicle comfort, provides a foundation for subsequent vehicle-wide power supply maintenance by differentially setting engine speed limits.

[0041] like Figure 2 As shown, in step S400 above, the final range extender power output is determined based on the range extender's optimal economic line, engine comfort speed limit, power generation spectrum, and vehicle power demand. The specific process of step S400 is as follows: First, the range extender's power output is obtained. Based on the range extender's optimal economic curve and the corresponding comfort speed limit, the power output spectrum under different power generation intensities is determined. Before this, the range extender's optimal economic curve and the vehicle's required power are needed. The range extender's optimal economic curve is calculated based on data from the engine fuel consumption map and generator efficiency map, according to the principle of optimal efficiency where the range extender has the lowest specific fuel consumption at the same power level. The vehicle's required power is calculated in real time based on data such as vehicle speed, acceleration, gradient, accelerator pedal position, PedalMap (a graph showing the relationship between powertrain output torque and accelerator pedal opening and vehicle speed), and vehicle electrical power consumption.

[0042] Using engine speed as a variable, the range extender's power generation is obtained by looking up a table through the optimal economic line of the range extender. Then, the range extender's power generation map is obtained by corresponding to the engine comfort speed limit map. In this way, the range extender's power generation spectrum under different power generation intensities is obtained, such as Map1, Map2, and Map3.

[0043] Secondly, the power generation spectrum corresponding to the maximum power generation intensity is compared with the vehicle's power demand to determine the final range extender power generation. The specific determination rules are as follows: when the vehicle's power demand is less than the maximum value of the power generation spectrum corresponding to the maximum power generation intensity, power generation is based on the power generation spectrum; when the vehicle's power demand is greater than the maximum value of the power generation spectrum corresponding to the maximum power generation intensity, power generation is based on the vehicle's power demand, and is limited by the power generation capacity of the range extender hardware, such as the engine's external characteristics under different environments and the generator's real-time external characteristics. This logic fully considers the power reserve performance requirements under certain aggressive operating conditions, such as prolonged steep inclines and frequent rapid acceleration and deceleration. By linking the vehicle's power demand with the maximum power generation spectrum, it ensures that the engine generates power according to the high-efficiency economic zone spectrum under normal operating conditions, and generates power according to actual demand under extreme high-load conditions, thus ensuring both economy and power reserve limits.

[0044] like Figure 2 As shown, in step S500 above, the engine speed is determined based on the final range extender power output and the optimal economic line of the range extender, and the engine torque is determined based on the engine speed and the final range extender power output to determine the engine operating point. After determining the final range extender power output, the corresponding engine speed is obtained by looking up a table based on the final range extender power output and the optimal economic line of the range extender. Subsequently, the engine torque is calculated using the engine speed and the final range extender power output. At this point, the engine operating point (i.e., engine speed - engine torque) is completely determined. Since the entire calculation process is based on the optimal economic line of the range extender, the determined operating point ensures that the range extender operates in the economic zone, achieving efficient energy conversion.

[0045] The hybrid electric vehicle range extender power generation control method of this embodiment further includes: The start-up and stop-up thresholds are set based on the target battery state parameters and vehicle speed. When the actual battery state parameters are greater than the start-up threshold, the engine starts and operates according to the engine operating condition point. When the actual battery state parameters are less than the stop-up threshold, the engine stops.

[0046] By setting reasonable start-stop thresholds, the engine can be prevented from frequently starting and stopping near the critical battery level, while ensuring that the engine runs in the economic zone according to the aforementioned operating point immediately after starting, thus further optimizing the vehicle's energy consumption and NVH performance.

[0047] Secondly, embodiments of the present invention provide a power generation control system for a hybrid electric vehicle range extender. This system can be integrated into the vehicle controller of the hybrid electric vehicle and is used to execute the control method described in the above embodiments. The system includes the following modules: The first acquisition module is configured to acquire target battery state parameters, set multiple target battery state parameters based on different operating conditions, and take the maximum value as the final target battery state parameter. The first determining module is configured to determine the first power generation intensity based on the deviation between the final target battery state parameters and the actual battery state parameters, determine the second power generation intensity based on the actual battery state parameters, determine the third power generation intensity based on the road slope, and take the maximum value as the final power generation intensity coefficient. The second acquisition module is configured to acquire the engine comfort speed limit, set the basic comfort speed limit based on vehicle speed and accelerator pedal signal, and determine the corresponding comfort speed limit in combination with the final power generation intensity coefficient. The second determining module is configured to acquire the range extender's power generation, determine the power generation spectrum under different power generation intensities based on the range extender's optimal economic line and corresponding comfort speed limits, compare the power generation spectrum corresponding to the maximum power generation intensity with the vehicle's power demand, and determine the final range extender power generation; and The third determining module is configured to determine the engine speed based on the final range extender power generation and the optimal economic line of the range extender, and to determine the engine torque based on the engine speed and the final range extender power generation, so as to determine the engine operating condition point.

[0048] Specifically, the first acquisition module is configured to: set a first target battery state parameter based on ambient temperature, a second target battery state parameter based on road slope, and a third target battery state parameter based on vehicle speed; and take the maximum value of the first, second, and third target battery state parameters as the final target battery state parameter. The first acquisition module interacts with the battery management system (BMS), vehicle environmental sensors, and in-vehicle navigation system to acquire signals such as ambient temperature, slope, and vehicle speed. After internal logic processing, it outputs the final target battery state parameter to the first determination module.

[0049] The first determining module is configured as follows: the larger the absolute value of the deviation between the final target battery state parameters and the actual battery state parameters, the larger the first power generation intensity setting; the larger the actual battery state parameters or the higher the battery temperature, the smaller the second power generation intensity setting; the greater the road slope, the larger the third power generation intensity setting. The first determining module receives the target parameters output by the first acquiring module and the actual SOC and cell temperature fed back by the BMS, calculates the final power generation intensity coefficient, and transmits it to the second acquiring module and the second determining module.

[0050] The second acquisition module stores a Map of basic NVH speed limits corresponding to different vehicle speeds and accelerator pedals. After receiving the power generation intensity coefficient from the first determination module, it outputs the corresponding engine comfort speed limit to the second determination module through table lookup and calibration logic.

[0051] The second determining module is configured as follows: when the vehicle's required power is less than the maximum value of the power generation spectrum corresponding to the maximum power generation intensity, power generation is performed based on the power generation spectrum; when the vehicle's required power is greater than the maximum value of the power generation spectrum corresponding to the maximum power generation intensity, power generation is performed based on the vehicle's required power, and is limited by the range extender's hardware power generation capacity. The second determining module receives the comfort speed limit from the second acquisition module, the range extender's optimal economic line from the optimal economic line acquisition module, and the vehicle's required power from the vehicle's required power acquisition module. After logical judgment, it outputs the final range extender power generation to the third determining module.

[0052] The range extender power generation control system of this embodiment of the invention further includes a start-stop control module. The start-stop control module is configured to set a start threshold and a stop threshold based on the target battery state parameters and the vehicle speed; when the actual battery state parameters are greater than the start threshold, the engine starts and operates according to the engine operating condition point; when the actual battery state parameters are less than the stop threshold, the engine stops.

[0053] The range extender power generation control system of this invention also includes a vehicle power demand acquisition module. The vehicle power demand acquisition module is configured to calculate the vehicle power demand based on vehicle speed, acceleration, gradient, accelerator pedal position, and vehicle electrical power consumption.

[0054] The range extender power generation control system of this embodiment of the invention further includes an optimal economic line acquisition module. The optimal economic line acquisition module is configured to calculate the optimal economic line of the range extender based on the principle of minimum specific fuel consumption under equal power, according to the engine fuel consumption diagram and the generator efficiency diagram.

[0055] Thirdly, embodiments of the present invention also provide a vehicle including a range extender power generation control system with the above-described structure. The vehicle is a hybrid electric vehicle, and because the vehicle of the present invention includes the range extender power generation control system described in the above embodiments, it possesses all the advantages of the aforementioned range extender power generation control system.

[0056] By applying the above-mentioned range extender power generation control system, the vehicle in this embodiment of the invention can automatically balance driving comfort, battery power retention and energy economy under complex driving conditions, so as to achieve stable operation of the range extender in the economic zone and significantly reduce the fuel consumption of the whole vehicle. Example

[0057] The hybrid electric vehicle range extender power generation control method provided in this embodiment includes the following steps: Step 1) Based on the basic automotive theory, build a joint simulation model with the whole vehicle physical model (including the whole vehicle powertrain model, power battery physical model and whole vehicle control model) and the range extender physical model (including the engine physical model, generator physical model and range extender control model) as the main components, and the two modules interact with each other. Step 2) Calculate the vehicle's required power based on the physical model of the vehicle's powertrain. Specifically, this involves obtaining vehicle speed, acceleration, gradient, and accelerator pedal data from the vehicle model to calculate the mechanical power required at the vehicle's wheels. This power is then transmitted through the powertrain efficiency to obtain the range extender's electrical power. Combined with the vehicle's electrical voltage and current signals obtained from the vehicle model, the transient electrical power required by the vehicle, P1, can be calculated in real time. For example, this could be the steady-state power required by the vehicle at different speeds in a level road steady-state scenario, or the transient power required by the vehicle under different speeds and gradients.

[0058] Step 3) Calculate the optimal economic line of the range extender based on the physical model of the range extender. Specifically, this is reflected in the calculation of the optimal economic line (speed and power) of the mechanical end of the range extender based on the engine fuel consumption map (engine speed - engine torque - engine specific fuel consumption) and generator efficiency map (generator speed - generator torque - generator efficiency) data, and the principle of optimal efficiency (lowest specific fuel consumption of the range extender under the same power).

[0059] Step 4) Obtain the target SOC for the entire vehicle. First, set different target SOCs based on different scenarios, such as setting different target SOCs 1 based on different ambient temperatures, 2 based on different road slopes, and 3 based on different vehicle speeds. Then, take the largest value from all the target SOCs 1, 2, and 3 to obtain the final target SOC. The target SOC obtained in this way can cover the needs of multiple scenarios. For example, a larger target SOC can be defined in scenarios such as highways or mountain roads, which has strong battery discharge capacity and can meet the vehicle's power requirements; while a lower target SOC can be defined on low-speed flat roads, which can improve the pure electric range and reduce the frequent start-stop of the engine, avoiding problems such as high fuel consumption caused by the engine operating in the low-speed, low-efficiency zone.

[0060] Step 5) Obtain the range extender's power generation intensity coefficient. First, obtain signals such as the actual SOC and cell temperature from the power battery physical model. Second, based on the target SOC obtained in Step 4) and the actual SOC, obtain the SOC deviation (δSOC = actual SOC - target SOC). Based on the magnitude of the SOC deviation, set multiple levels of power generation intensity a1, a2, a3, etc. Specifically, the larger the δSOC value, the larger the range extender's power generation intensity a value. Based on the actual SOC and cell temperature signals, multiple levels of power generation intensity, such as b1, b2, and b3, are set. Specifically, the larger the SOC or the higher the cell temperature, the stronger the battery discharge capacity, and the smaller the required power generation intensity, i.e., the smaller the b value. Then, based on the slope, power generation intensity, such as c1, c2, and c3, is set. Specifically, the greater the slope, the greater the power generation intensity c value. Finally, the largest value among the power generation intensity coefficients a, b, and c (the larger the value, the greater the power generation intensity) is taken to obtain the final range extender power generation intensity coefficient.

[0061] Step 6) Obtain the engine NVH speed limit. Based on the vehicle speed and accelerator pedal signal, set the engine NVH speed limit Map. Specifically, the lower the vehicle speed or the smaller the accelerator pedal input, the lower the engine NVH speed limit, resulting in better vehicle comfort. Conversely, the higher the vehicle speed or the larger the accelerator pedal input, the higher the allowable engine NVH speed limit becomes, with tire noise or wind noise being the primary noise source. This ensures both vehicle comfort and energy conservation performance. Then, based on the range extender's power generation intensity obtained in Step 5), set corresponding engine NVH speed limits Map1, Map2, Map3, etc., for different levels of power generation intensity. The higher the power generation intensity, the higher the engine NVH speed limit, and the greater the allowable power generation of the range extender, thus achieving the goal of maintaining vehicle energy conservation.

[0062] Step 7) Obtain the engine operating condition point. Based on the optimal economic line of the range extender obtained in Step 3) and the engine NVH speed limit value Map obtained in Step 6), using engine speed as a variable, the range extender power generation is obtained by looking up the table through the optimal economic line of the range extender. The corresponding NVH speed limit value Map is used to obtain the range extender power generation Map, thus obtaining the range extender power generation Map1, Map2, Map3, etc. under different power generation intensities. At this time, it can be ensured that the engine operates in the economic zone. However, considering the power supply performance under certain aggressive operating conditions, such as the vehicle climbing steep hills for a long time, or frequent rapid acceleration and deceleration, the power generation Map3 corresponding to the maximum power generation intensity obtained above is correlated with the vehicle demand power obtained in Step 2). When the vehicle demand power is less than the power generation Map corresponding to the maximum power generation intensity, the range extender generates power using the power generation Map. When the vehicle demand power is greater than the power generation Map corresponding to the maximum power generation intensity, the range extender generates power using the vehicle demand power, which is limited by the power generation capacity of the range extender hardware (external characteristics of the engine under different environments and real-time external characteristics of the generator). Then, based on the final range extender power output obtained above and the optimal economic line of the range extender obtained in step 3), the engine speed is obtained by looking up the table. Finally, the engine torque is calculated by using the engine speed and the range extender power output, and the engine operating point (engine speed - engine torque) is determined.

[0063] Step 8) Based on the target SOC and vehicle speed obtained in Step 4), set the range extender start SOC threshold and the range extender stop SOC threshold. When the actual battery SOC is greater than the range extender start SOC threshold, the engine starts and operates in the economic zone according to the above control logic. When the actual battery SOC is less than the range extender stop SOC threshold, the engine stops.

[0064] The present invention has been described above by way of example with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvements made using the inventive concept and technical solution of the present invention, or the direct application of the inventive concept and technical solution of the present invention to other occasions without modification, are all within the protection scope of the present invention.

Claims

1. A method for controlling the power generation of a hybrid electric vehicle range extender, characterized in that, include: Determine the final target battery state parameters; The first power generation intensity is determined based on the deviation between the final target battery state parameters and the actual battery state parameters. The second power generation intensity is determined based on the actual battery state parameters. The third power generation intensity is determined based on the road slope. The maximum value of the first power generation intensity, the second power generation intensity and the third power generation intensity is taken as the final power generation intensity coefficient. The engine comfort speed limit is determined based on vehicle speed, accelerator pedal signal, and final power generation intensity coefficient. Based on the optimal economic line of the range extender, the engine comfort speed limit, the power generation spectrum and the power demand of the whole vehicle, the final power generation of the range extender is determined. The engine speed is determined based on the final range extender power output and the optimal economic line of the range extender, and the engine torque is determined based on the engine speed and the final range extender power output, so as to determine the engine operating condition point.

2. The hybrid electric vehicle range extender power generation control method according to claim 1, characterized in that, Obtain the target battery state parameters, set multiple target battery state parameters based on different operating conditions, and take the maximum value as the final target battery state parameter.

3. The hybrid electric vehicle range extender power generation control method according to claim 2, characterized in that, The acquisition of target battery state parameters includes: setting a first target battery state parameter based on ambient temperature, setting a second target battery state parameter based on road slope, setting a third target battery state parameter based on vehicle speed, and taking the maximum value of the first target battery state parameter, the second target battery state parameter, and the third target battery state parameter as the final target battery state parameter.

4. The method for controlling the power generation of a hybrid electric vehicle range extender according to claim 1, characterized in that, The determination of the final power generation intensity coefficient includes: the greater the absolute value of the deviation between the final target battery state parameter and the actual battery state parameter, the greater the first power generation intensity setting; the greater the actual battery state parameter or the higher the battery temperature, the smaller the second power generation intensity setting; the greater the road slope, the greater the third power generation intensity setting.

5. The method for controlling the power generation of a hybrid electric vehicle range extender according to claim 1, characterized in that, The determination of the final range extender power output includes: when the vehicle's required power output is less than the maximum value of the power output spectrum corresponding to the maximum power output intensity, power is generated using the power output spectrum; when the vehicle's required power output is greater than the maximum value of the power output spectrum corresponding to the maximum power output intensity, power is generated using the vehicle's required power output.

6. The method for controlling the power generation of a hybrid electric vehicle range extender according to claim 1, characterized in that, Also includes: Based on the target battery state parameters and vehicle speed, start-up and stop-up thresholds are set; when the actual battery state parameters are greater than the start-up threshold, the engine starts and operates according to the engine operating condition point; when the actual battery state parameters are less than the stop-up threshold, the engine stops.

7. A power generation control system for a hybrid electric vehicle range extender, characterized in that, include: The first acquisition module is configured to acquire target battery state parameters, set multiple target battery state parameters based on different operating conditions, and take the maximum value as the final target battery state parameter. The first determining module is configured to determine the first power generation intensity based on the deviation between the final target battery state parameters and the actual battery state parameters, determine the second power generation intensity based on the actual battery state parameters, determine the third power generation intensity based on the road slope, and take the maximum value as the final power generation intensity coefficient. The second acquisition module is configured to acquire the engine comfort speed limit, set the basic comfort speed limit based on vehicle speed and accelerator pedal signal, and determine the corresponding comfort speed limit in combination with the final power generation intensity coefficient. The second determining module is configured to obtain the range extender's power generation, determine the power generation spectrum under different power generation intensities based on the range extender's optimal economic line and the corresponding comfort speed limit, compare the power generation spectrum corresponding to the maximum power generation intensity with the vehicle's required power, and determine the final range extender's power generation. as well as The third determining module is configured to determine the engine speed based on the final range extender power generation and the optimal economic line of the range extender, and to determine the engine torque based on the engine speed and the final range extender power generation, so as to determine the engine operating condition point.

8. The range extender power generation control system according to claim 7, characterized in that, The first acquisition module is configured to: set a first target battery state parameter based on ambient temperature, set a second target battery state parameter based on road slope, set a third target battery state parameter based on vehicle speed, and take the maximum value of the first target battery state parameter, the second target battery state parameter, and the third target battery state parameter as the final target battery state parameter.

9. The range extender power generation control system according to claim 7, characterized in that, The first determining module is configured such that: the greater the absolute value of the deviation between the final target battery state parameter and the actual battery state parameter, the greater the first power generation intensity setting; the greater the actual battery state parameter or the higher the battery temperature, the smaller the second power generation intensity setting; and the greater the road slope, the greater the third power generation intensity setting.

10. The range extender power generation control system according to claim 7, characterized in that, The second determining module is configured to generate electricity using the power generation spectrum when the vehicle's required power is less than the maximum value of the power generation spectrum corresponding to the maximum power generation intensity; and to generate electricity using the vehicle's required power when the vehicle's required power is greater than the maximum value of the power generation spectrum corresponding to the maximum power generation intensity, subject to the power generation capacity of the range extender hardware.

11. The range extender power generation control system according to claim 7, characterized in that, It also includes a start-stop control module, configured to set start-up and stop-up thresholds based on the target battery state parameters and vehicle speed; when the actual battery state parameters are greater than the start-up threshold, the engine starts and operates according to the engine operating condition point; when the actual battery state parameters are less than the stop-up threshold, the engine stops.

12. The range extender power generation control system according to claim 7, characterized in that, It also includes a vehicle power demand acquisition module, which is configured to calculate the vehicle power demand based on vehicle speed, acceleration, gradient, accelerator pedal, and vehicle electrical power consumption.

13. The range extender power generation control system according to claim 7, characterized in that, It also includes an optimal economic line acquisition module, which is configured to calculate the optimal economic line of the range extender based on the principle of the lowest specific fuel consumption under the same power, according to the engine fuel consumption map and the generator efficiency map.

14. A vehicle, characterized in that, The range extender power generation control system includes any one of claims 7-13.

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