Method, medium and product for switching operating modes of hybrid drive system
By acquiring and analyzing data on speed, torque and mode capability in the hybrid system, and judging and performing mode switching, the problem of insufficient power during mode switching is solved, and a safe and cost-effective driving experience is achieved.
Patent Information
- Application Number
- CN202510401569.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-01
- Publication Date
- 2025-06-03
AI Technical Summary
During the operation mode switching of the hybrid system, insufficient power may occur, affecting driving safety and driving experience.
By obtaining the current and predicted speed, required torque, and torque capabilities of each operating mode, it is determined whether mode switching is required and the target mode is selected based on the number of potentially available modes to ensure that insufficient power is minimized during mode switching.
It effectively avoids the problem of insufficient power during mode switching, ensures driving safety and a good driving experience, while taking into account both economic and efficiency.
Smart Images
Figure CN120080836A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of vehicles, and more particularly, to a method, a computer-readable storage medium, and a computer program product for switching operating modes of a hybrid system. Background Art
[0002] A hybrid system has multiple power sources that can be interconnected with each other and are all coupled to a drive shaft to provide power individually or jointly. The power sources to be used (e.g., a power battery, an engine) and the connection configuration between these power sources (e.g., series or parallel) can be selected according to different usage scenarios, thereby forming multiple power transmission forms. The hybrid system can thus have multiple different operating modes, and these operating modes can provide different speed-torque curves to cope with more complex driving scenarios.
[0003] The hybrid system can switch between these different operating modes according to different requirements for efficiency or power. During the mode switching process, it is necessary to ensure that the hybrid system can always provide additional torque to cope with possible unexpected situations, thereby ensuring driving safety and reducing the experience of the driver feeling a lack of power.
[0004] It should be noted that the information disclosed in the above background art section is only used to enhance the understanding of the background of the present application, and thus may include information that does not constitute the prior art known to those of ordinary skill in the art. Summary of the Invention
[0005] To solve or at least alleviate one or more of the above problems, the following technical solutions are provided. Embodiments of the present application provide a method, a medium, and a product for switching operating modes of a hybrid system, ensuring that the situation of power shortage is minimized as much as possible during the mode switching process.
[0006] According to a first aspect of the present application, there is provided a method for switching operating modes of a hybrid system, the method including: obtaining a current speed, a current required torque at the current speed, and a current torque capacity of each operating mode; calculating a predicted speed, a predicted required torque at the predicted speed, and a predicted torque capacity of each operating mode; determining whether a mode switch is required according to a difference between the current torque capacity and the current required torque of the current mode and a difference between the predicted torque capacity and the predicted required torque of the current mode; and in response to determining that a mode switch is required, selecting a target mode according to the number of potentially available modes.
[0007] As an alternative or supplement to the above solution, in the method according to an embodiment of the present application, determining whether a mode switch is required based on the difference between the current torque capacity and the current required torque of the current mode and the difference between the predicted torque capacity and the predicted required torque of the current mode includes: if the difference between the current torque capacity and the current required torque of the current mode is greater than a first threshold and the difference between the predicted torque capacity and the predicted required torque of the current mode is greater than a second threshold, then no mode switch is required, where the second threshold corresponds to the torque lost during the mode switch of the current mode.
[0008] As an alternative or supplement to the above solution, in the method according to an embodiment of the present application, the current torque capacity of the potentially available mode is greater than the current torque capacity of the current mode, and the predicted torque capacity of the potentially available mode is greater than the predicted torque capacity of the current mode.
[0009] As an alternative or supplement to the above solution, in the method according to an embodiment of the present application, the difference between the current torque capacity and the current required torque of the potentially available mode is greater than a first threshold.
[0010] As an alternative or supplement to the above solution, in the method according to an embodiment of the present application, the difference between the predicted torque capacity and the predicted required torque of the potentially available mode is greater than a second threshold.
[0011] As an alternative or supplement to the above solution, in the method according to an embodiment of the present application, selecting a target mode based on the number of potentially available modes includes: if the number of potentially available modes is greater than 1, then selecting the potentially available mode with the optimal efficiency as the target mode.
[0012] As an alternative or supplement to the above solution, in the method according to an embodiment of the present application, selecting a target mode based on the number of potentially available modes includes: if the number of potentially available modes is 0, then selecting the mode with the largest predicted torque capacity value as the target mode.
[0013] According to a second aspect of the present application, there is provided a hybrid power system, the system including: a plurality of power sources connected to each other; a drive shaft coupled to the plurality of power sources; and a controller configured to execute any one of the methods described in the first aspect of the present application.
[0014] As an alternative or supplement to the above solution, in the hybrid power system according to an embodiment of the present application, the plurality of power sources include an engine and a power battery, and the engine is connected to the power battery via a generator.
[0015] According to a third aspect of the present application, there is provided a computer-readable storage medium, which includes instructions that, when running, execute any one of the methods described in the first aspect of the present application.
[0016] According to a fourth aspect of the present application, there is provided a computer program product, which includes instructions that, when running, execute any one of the methods described in the first aspect of the present application.
[0017] The method for switching the operating mode of a hybrid power system according to one or more embodiments of the present application takes into account the power shortage caused by possible torque losses during the process of executing the switching process for various operating modes. During the actual execution of mode switching, such experiences are avoided by performing the switching of the operating mode in advance, thereby ensuring driving safety and driving experience. Further, during the selection process of potentially available operating modes, economy and efficiency are taken into account. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The above and / or other aspects and advantages of the present application will become clearer and easier to understand through the following descriptions of various aspects in conjunction with the drawings, where the same or similar units are denoted by the same reference numerals. In the said drawings:
[0019] Figure 1 is a schematic diagram of a hybrid power system 100 according to an embodiment of the present application;
[0020] Figure 2 is a flowchart of a method 200 for switching the operating mode of a hybrid power system according to an embodiment of the present application;
[0021] Figure 3 is an example situation of the change of the operating point of a hybrid power system according to an embodiment of the present application; and
[0022] Figure 4 is another example situation of the change of the operating point of a hybrid power system according to an embodiment of the present application. DETAILED DESCRIPTION
[0023] The following description of the detailed implementation is essentially only exemplary and is not intended to limit the disclosed technology or the application and use of the disclosed technology. In addition, there is no intention to be bound by any theory, whether explicit or implicit, presented in the foregoing technical field, background art, or the following detailed implementation.
[0024] In the following detailed description of the embodiments, numerous specific details are set forth in order to provide a more thorough understanding of the disclosed technology. However, it will be apparent to one of ordinary skill in the art that the disclosed technology may be practiced without these specific details. In other instances, well-known features have not been described in detail to avoid unnecessarily complicating the description.
[0025] Terms such as "comprising" and "including" mean that in addition to the units (modules) and steps directly and explicitly recited in the specification and claims, the technical solutions of the present application do not exclude the case of having other units (modules) and steps that are not directly or explicitly recited. Terms such as "first" and "second" do not denote the order of the units in terms of time, space, size, etc., but are merely used to distinguish the units. Also, the steps herein are not limited to being implemented in the written order, but the steps written later can also be implemented simultaneously with the steps written earlier, or implemented prior to the steps written earlier.
[0026] Figure 1 is a schematic diagram of a hybrid power system 100 according to an embodiment of the present application. As Figure 1 shown, the hybrid power system 100 includes an engine 1, a generator 2, a reduction gear 3, a power battery 4, an inverter 5, a drive motor 6, a clutch 7, a drive shaft 8, and a controller (not shown in the figure, which is configured to execute the method for switching the operating mode of the hybrid power system described below); wherein, both the engine 1 and the power battery 4 can be used as power sources. In some embodiments, the hybrid power system may further include other power sources. In Figure 1 the hybrid power system 100, the engine 1 is connected to the generator 2 through the reduction gear 3 to generate electricity, and the engine 1 can also be coupled or decoupled from the drive shaft 8 via the clutch 7. The generator 2 is connected to the drive motor 6 and the power battery 4 via the inverter 5, and the drive motor 6 can be connected to the drive shaft 8. When the hybrid power system 100 operates in the pure electric mode, the engine 1 and the generator 2 do not work, the clutch 7 is in the disengaged state, and the power battery 4 supplies power to the drive motor 6 via the inverter 5, and the drive motor 6 provides power to the drive shaft 8. When the hybrid power system 100 operates in the series mode, the clutch 7 is in the disengaged state, the engine 1 is connected to the generator 2 through the reduction gear 3 to generate electricity, and the generator 2 and the power battery 4 jointly supply power to the drive motor 6 via the inverter 5 to provide power to the drive shaft 8. When the hybrid power system 100 operates in the parallel mode, the clutch 7 is in the engaged state, the engine 1 provides power to the drive shaft 8 via the clutch 7, and at the same time the power battery 4 supplies power to the drive motor 6 via the inverter 5 to provide power to the drive shaft 8. In the pure electric mode, the series mode, and the parallel mode, the fuel consumption of the hybrid power system 100 increases in sequence, and at the same time its output torque capacity also increases accordingly.
[0027] When the hybrid system 100 operating in the pure electric mode needs a greater output torque, the hybrid system 100 can switch from the pure electric mode to the series mode. During this switching process, starting the engine 1 requires a certain amount of time and power. Therefore, during the switching process, not all of the power of the power battery 4 can be used for driving, which results in the maximum output torque that the hybrid system 100 can output before the engine 1 completes starting during the switching from the pure electric mode to the series mode may be less than the maximum output torque of the pure electric mode (due to the power consumption or torque loss required to start the engine). Similarly, when the hybrid system 100 operating in the series mode further needs a greater torque output, the hybrid system 100 can switch from the series mode to the parallel mode. During this switching process, closing the clutch 7 requires a certain amount of time and torque loss. Therefore, this results in the maximum output torque that the hybrid system 100 can output when the clutch 7 is not fully closed may be less than the maximum output torque of the series mode. To reduce the experience of power deficiency during the mode switching process, the above two situations need to be taken into account.
[0028] Figure 2 is a flowchart of a method 200 for switching the operating mode of a hybrid system according to an embodiment of the present application. Figure 2 The method 200 shown can be used for a hybrid system as shown in Figure 1 The system includes: a plurality of power sources connected to each other; a drive shaft coupled to the plurality of power sources; and a controller configured to execute a method as shown in Figure 2 In some embodiments, the plurality of power sources include an engine and a power battery, and the engine is connected to the power battery via a generator.
[0029] In step 210, the controller obtains the current speed V Cur and the current required torque T Cur at the current speed V ReqCur and the current torque capacity of each operating mode. In embodiments where the plurality of power sources include an engine and a power battery, the hybrid system may have three operating modes: pure electric mode, series mode, and parallel mode. Among them, the current torque capacity of the pure electric mode is T CapCurEV ; the current torque capacity of the series mode is T CapCurEREV ; the current torque capacity of the parallel mode is T CapCurParl . The current required torque T ReqCur can be obtained by looking up a table according to the current speed V Cur and the throttle pedal opening. Since the relationship between power, torque, and rotational speed satisfies T = 9550*P / n, the current torque capacity of the pure electric mode can be calculated by the following formula:
[0030]
[0031] In pure electric mode, the output power on the drive shaft may be limited by the battery discharge power capability P BatDisCap or the current power capability P of the motor CapCurMotB whichever is smaller, and the rotational speed on the drive shaft (corresponding to the vehicle speed) is the motor rotational speed n MotB multiplied by the speed ratio r from the motor to the drive shaft MotB .
[0032] The current torque capability in series mode can be calculated by the following formula:
[0033]
[0034] In series mode, the output power on the drive shaft may be limited by the output power of the series power sources or the current power capability P of the motor CapCurMotB whichever is smaller, where the series power sources include the battery and the engine, and the engine supplies power via a generator. The output power of the series power sources is the sum of the battery discharge power capability P BatDisCap and the power supplied by the engine via the generator, and the power supplied by the engine via the generator may be limited by the maximum engine power P EngMax or the current power capability P of the generator at the current rotational speed CapCurMotA whichever is smaller, and the rotational speed on the drive shaft is the motor rotational speed n MotB multiplied by the speed ratio r from the motor to the drive shaft MotB .
[0035] The current torque capability in parallel mode can be calculated by the following formula:
[0036] T CapCurParl = T CapCurEV + T CapCurEng × r Eng (3)
[0037] The torque capability in parallel mode is the sum of the current torque capability T in pure electric mode CapCurEV and the current engine torque capability T CapCurEng multiplied by the speed ratio r from the engine to the drive shaft Eng where the current torque capability T in pure electric mode CapCurEV can be calculated by formula (1).
[0038] With the help of formulas (1) to (3), it is possible to calculate through the battery discharge power capability P BatDisCap , the current power capability P of the motor CapCurMotB , the maximum engine power P EngMax, the current power capacity P of the generator CapCurMotA , the current torque capacity T of the engine CapCurEng , the gear ratio r Eng and r MotB and other parameters (these parameters are inherent parameters or can be obtained through the current speed) combined with the current speed V Cur and the associated rotational speed n MotB to obtain the torque capacity of each current operating mode.
[0039] Then, in step 220, the predicted speed and the predicted required torque at the predicted speed and the predicted torque capacity of each operating mode are calculated. For example, in step 220, the predicted speed can be calculated using the following formula:
[0040] V Pre = V Cur + t trans × a (4)
[0041] where V Cur is the current speed of the vehicle, t trans is the minimum duration required for mode switching, and a is the average acceleration of the vehicle. In other embodiments, the predicted speed can also be calculated through historical data related to driving habits or other technologies. After obtaining the predicted speed V of the vehicle Pre , the predicted torque capacity of each mode at the predicted speed is calculated. In some embodiments, the predicted torque capacity of the pure electric mode is calculated by the following formula:
[0042]
[0043] Similar to formula (1), P BatDisCap is the battery discharge power capacity, P CapPreMot is the predicted power capacity of the motor associated with the predicted speed V Pre , n MotBPre is the predicted rotational speed of the motor associated with the predicted speed V Pre , r MotB is the gear ratio from the motor to the drive shaft.
[0044] The predicted torque capacity of the series mode can be calculated by the following formula:
[0045]
[0046] where P EngMaxPre is the predicted maximum power of the engine, P CapPreMotA is the predicted power capacity of the generator, P CapPreMotB is the predicted power capacity of the motor, n MotBPre is the predicted rotational speed of the motor.
[0047] The predictive torque capability in parallel mode can be calculated by the following formula:
[0048]
[0049] Where P BatDisCap is the battery discharge power capability, P CapPreMotB is the predictive power capability of the motor, n MotBPre is the predicted rotational speed of the motor, r MotB is the speed ratio from the motor to the drive shaft, T CappreEng is the predicted torque capability of the engine, r Eng is the speed ratio from the engine to the drive shaft.
[0050] Then, the predicted required torque at the predicted speed can be calculated by the following formula:
[0051] T ReqPre = min(max(T CapPreEV , T CapPreEREV , T CapPreParl ), T ReqCur , T SusDrvCur ) (8)
[0053] Where T ReqCur is the current required torque at the current speed, T SusDrvCur is the torque required to maintain the vehicle driving state, which can be obtained by looking up a table based on the current vehicle speed and slope.
[0054] Through step S220, the controller can calculate the predicted speed V Pre and the predicted required torque (T ReqPre ) at the predicted speed and the predictive torque capabilities of each operating mode (e.g., T CapPreEV , T CapPreEREV , T CapPreParl ). In some embodiments, the controller can also look up the torque corresponding to the current speed or the predicted speed on the speed-torque curve of various operating modes to determine the current torque capability and the predictive torque capability of the corresponding operating mode. In some embodiments, the hybrid system may further include other operating modes, for example, a pure engine drive mode (applicable in the case of an electric drive system failure).
[0055] Then, in step S230, it is determined whether a mode switch is needed based on the difference between the current torque capability and the current required torque of the current mode and the difference between the predictive torque capability and the predicted required torque of the current mode. Specifically, first, it is judged whether the current torque capability (e.g., T CapCurEV , T CapCurEREV or T CapCurParl ) in the current mode of the vehicle and the current required torque (TReqCur ) whether the difference between is less than a first threshold (Cal TrqOfst1 ), the first threshold is a non-zero value, which is related to vehicle speed, battery SOC, engine cold state, accelerator / brake pedal opening, and can be obtained by looking up a table. This difference reflects the margin of torque capacity of the current mode at the current speed. If this difference is less than the first threshold, it means that the margin of torque capacity of the current mode at the current speed is insufficient to cope with possible emergencies, so a mode switch needs to be made in advance during the change of the current operating point. Otherwise, it means that the margin of torque capacity of the current mode at the current speed is sufficient and further judgment is needed. Then, judge whether the predicted torque capacity of the current mode (e.g., T CapPreEV 、T CapPreERE or T CapPreParl ) and the difference between the predicted required torque (T ReqPre ) is less than a second threshold (Cal TrqOfst2 ), the second threshold corresponds to the torque loss during the mode switch of the current mode. The loss of torque may originate from the start of the engine, the closing of the clutch or the like. The difference between the predicted torque capacity of the current mode and the predicted required torque reflects the margin of torque capacity of the current mode at the predicted speed. If this difference is less than the second threshold, it means that the margin of torque capacity of the current mode at the predicted speed is insufficient to cover the torque loss during the subsequent mode switch of the current mode at the predicted speed, so a mode switch needs to be made in advance during the change of the current operating point. Otherwise, it means that the margin of torque capacity of the current mode at the predicted speed is also sufficient and no mode switch is required, and the vehicle driving state continues to be monitored.
[0056] Through step S230, it can be judged whether the current mode can maintain a sufficient margin of torque capacity at both the current speed and the predicted speed. If the current torque capacity of the current mode exceeds the current required torque by more than the first threshold and the predicted torque capacity of the current mode exceeds the predicted required torque by more than the second threshold, no mode switch is required, otherwise a mode switch is required. That is, only when the current mode can maintain a sufficient margin of torque capacity at both the current speed and the predicted speed, the current mode will be maintained, otherwise a mode switch will be made to provide an additional margin of torque capacity to ensure that there will be no torque shortage during driving and affect the driving experience.
[0057] In step S240, in response to determining in step S230 that a mode switch is required, the controller may select a target mode based on the number of potentially available modes. Specifically, after determining in step S230 that a mode switch is required, in step S240, the controller first needs to determine the number of potentially available modes, and then select the target mode to switch to based on the number of potentially available modes. If the number of potentially available modes is greater than 1, it means that there are multiple modes available for switching. In this case, selecting the potentially available mode with the optimal efficiency as the target mode can take into account economic considerations in addition to meeting the torque capacity requirements. If the number of potentially available modes is 0, it means that there is no operating mode available for switching. In this case, select the mode with the maximum torque capacity among all modes as the target mode, so as to minimize the experience of torque shortage during driving.
[0058] Further, in some embodiments, the potentially available mode can provide more torque than the current operating mode at both the current speed and the predicted speed. That is, the current torque capacity of the potentially available mode is greater than the current torque capacity of the current mode, and the predicted torque capacity of the potentially available mode is greater than the predicted torque capacity of the current mode. In other embodiments, the potentially available mode can be an operating mode that can provide a sufficient margin of torque capacity at the current speed. That is, the current torque capacity of the potentially available mode exceeds the current required torque by more than a first threshold. In still other embodiments, the potentially available mode can be an operating mode that can provide a sufficient margin of torque capacity at the predicted speed. That is, the predicted torque capacity of the potentially available mode exceeds the predicted required torque by more than a second threshold. In other embodiments, the potentially available mode can also be an operating mode that simultaneously meets one or more of the above conditions.
[0059] Figure 3 is an example of the change of the operating point of a hybrid power system according to an embodiment of the present application. Figure 3 The solid lines in show the speed-torque curves of the hybrid power system in pure electric, series, and parallel modes, Figure 3 The dashed lines in show the engine start prediction ability boundary and the clutch closing prediction ability boundary. In addition, Figure 3 also shows the operating points N1 and N2.
[0060] In Figure 3In the case where the hybrid system needs to change from operating point N1 to operating point N2, at operating point N1, the vehicle speed is the current speed (V_Cur), and the controller of the hybrid system can obtain the current required torque (T_ReqCur) based on the current speed and the current accelerator pedal opening table. Both the pure electric mode and the series mode can provide the speed and torque required at operating point N1. However, in the pure electric mode, the vehicle is fully powered by the battery and the engine does not need to be started. Therefore, the pure electric mode is preferred at operating point N1 due to its higher economy (lower fuel consumption). On the other hand, the parallel mode has the highest fuel consumption, so it will only be considered when neither the pure electric mode nor the series mode can provide the corresponding torque output at higher speeds. Therefore, at operating point N1, the use of the parallel mode does not need to be considered.
[0061] As described above, when the vehicle is at operating point N1, it operates in the pure electric mode. When the vehicle needs to further increase the speed and torque to reach operating point N2, the driver steps on the accelerator pedal, and the hybrid system changes from N1 to N2. As Figure 3 shown in the figure, operating point N2 corresponds to the predicted speed (V_Pre) and the predicted required torque (T_ReqPre). Operating point N2 can be achieved through the pure electric mode and the series mode, and there is no need to consider achieving it through the parallel mode. Considering energy consumption, or without considering the instantaneous power shortage caused by the switching process, when the controller determines that the target operating point is N2, the hybrid system will be maintained in the pure electric mode because operating point N2 does not exceed the speed-torque curve of the pure electric mode. However, as Figure 3 shown in the figure, operating point N2 has exceeded the engine start prediction ability boundary (that is, the difference between the predicted torque ability of the pure electric mode and the predicted required torque corresponding to operating point N2 is not greater than the second threshold). This means that if the hybrid system needs to start the engine (switch from the pure electric mode to the series or parallel mode) after operating point N2 to obtain higher speed or output torque, in the subsequent switching process, the operating point may exceed the speed-torque curve that the hybrid system can actually provide (which is actually part of the engine start prediction ability boundary). In this case, there will be an instantaneous power shortage. Therefore, after changing from operating point N1 to operating point N2 in the pure electric mode, although the pure electric mode can still be used to meet operating point N2, in the subsequent process of further changing from operating point N2 to an operating point with higher speed or torque, there may be an instantaneous power shortage.
[0062] The method 200 for switching the operating mode of a hybrid system according to an embodiment of the present application takes into account Figure 3This is the situation of the operating point change in []. Specifically, at the operating point N1, the vehicle operates in the pure electric mode. Through step S210, the controller obtains the current required torque (T_ReqCur) at the current speed (V_Cur) and the current torque capabilities of each operating mode (T_CapCurEV corresponding to V_Cur on the pure electric mode curve and T_CapCurEREV corresponding to V_Cur on the series mode curve). Then, through step S220, the controller can calculate the predicted speed (V_Pre) and the predicted required torque (T_ReqPre) at the predicted speed, as well as the predicted torque capabilities of each operating mode (T_CapPreEV corresponding to V_Pre on the pure electric mode curve and T_CapPreEREV corresponding to V_Pre on the series mode curve). Next, through step S230, the controller first determines that the difference between the current torque capability (T_CapCurEV) and the current required torque (T_ReqCur) in the current mode of the vehicle is greater than the first threshold (Cal_TrqOfst1), and then determines that the difference between the predicted torque capability (T_CapPreEV) and the predicted required torque (T_ReqPre) in the current mode is less than the second threshold (Cal_TrqOfst2). That is, the current mode (pure electric) can provide a sufficient margin of torque capability at the current speed but cannot provide a sufficient margin of torque capability at the predicted speed. Therefore, a mode switch is required. Finally, through step S240, the controller can determine that the series mode is the only potentially available mode and select the series mode as the target mode for switching. Through method 200, during the process of the vehicle changing from the operating point N1 to the operating point N2, the operating mode is switched from the pure electric mode to the series mode in advance, so that when at the operating point N2, the engine has already completed the starting process in advance and entered the series mode, thus avoiding the situation of insufficient torque that may occur when switching from the pure electric mode to other operating modes at the operating point N2.
[0063] Figure 4 This is another example situation of the operating point change of the hybrid power system according to an embodiment of the present application. Similar to Figure 3 , Figure 4 The solid lines in [] show the speed-torque curves of the hybrid power system in the pure electric, series, and parallel modes, Figure 4 and the dashed lines in [] show the engine start prediction capability boundary and the clutch closing prediction capability boundary. Different from Figure 3 , Figure 4 the operating points N3 and N4 are shown in [].
[0064] At Figure 4In the case where the hybrid system needs to change from operating point N3 to operating point N4, at operating point N3, the vehicle speed is the current speed (V_Cur), and the controller of the hybrid system can obtain the current required torque (T_ReqCur) based on the current speed and the current throttle pedal opening. At this time, the pure electric mode cannot provide the current required torque at the current speed, so it is not considered. Both the series mode and the parallel mode can provide the speed and torque at operating point N3. However, the series mode is preferentially considered at operating point N3 due to its higher economy (lower fuel consumption).
[0065] As described above, when the vehicle is at operating point N3, it operates in the series mode. When the vehicle needs to further increase the speed and torque to reach operating point N4, the hybrid system switches from N3 to N4. As Figure 4 shown in the figure, operating point N4 corresponds to the predicted speed (V_Pre) and the predicted required torque (T_ReqPre), and operating point N4 can be achieved by both the series mode and the parallel mode. Considering energy consumption, or without considering the instantaneous power shortage caused by the switching process, when the controller determines that the target operating point is N4, the hybrid system will be maintained in the series mode because operating point N4 does not exceed the speed-torque curve of the series mode. However, as Figure 4 shown in the figure, operating point N4 has exceeded the clutch closing prediction ability boundary (the difference between the predicted torque ability of the series mode and the predicted required torque corresponding to operating point N4 is not greater than the second threshold), which means that if the hybrid system needs the engine to provide more power (switch from the series mode to the parallel mode) after operating point N4 to obtain a higher speed or output torque, in the subsequent switching process, the operating point may exceed the speed-torque curve that the hybrid system can actually provide (which is actually part of the clutch closing prediction ability boundary), and in this case, there will be an instantaneous power shortage. Therefore, after switching from operating point N3 to operating point N4 in the series mode, although the series mode can still be used to meet operating point N4, in the subsequent switching process from operating point N4 to an operating point with higher speed or torque, there may be an instantaneous power shortage situation.
[0066] The method 200 for switching the operating mode of a hybrid system according to an embodiment of the present application also takes into account Figure 4The situation of such a change in the operating point. Specifically, at the operating point N3, the vehicle operates in the series mode. Through step S210, the controller obtains the current required torque (T_ReqCur) at the current speed (V_Cur) and the current torque capabilities of each operating mode (T_CapCurEREV corresponding to V_Cur on the series mode curve and T_CapCurParl corresponding to V_Cur on the parallel mode curve). Then, through step S220, the controller can calculate the predicted speed (V_Pre) and the predicted required torque (T_ReqPre) at the predicted speed, as well as the predicted torque capabilities of each operating mode (T_CapPreEREV corresponding to V_Pre on the series mode curve and T_CapPreParl corresponding to V_Pre on the parallel mode curve). Next, through step S230, the controller first determines that the difference between the current torque capability (T_CapCurEREV) and the current required torque (T_ReqCur) in the current mode of the vehicle is greater than the first threshold (Cal_TrqOfst1), and then determines that the difference between the predicted torque capability (T_CapPreEREV) and the predicted required torque (T_ReqPre) in the current mode is less than the second threshold (Cal_TrqOfst2). That is, the current mode (series) can provide a sufficient margin of torque capability at the current speed but cannot provide a sufficient margin of torque capability at the predicted speed. Therefore, a mode switch is required. Finally, through step S240, the controller can determine that the parallel mode is the only potentially available mode and select the parallel mode as the target mode for switching. Through method 200, during the process of the vehicle changing from the operating point N3 to the operating point N4, the operating mode is switched from the series mode to the parallel mode in advance, so that when at the operating point N4, the clutch has already completed the closing process in advance and entered the parallel mode, thus avoiding the situation of insufficient torque that may occur when switching from the series mode to the parallel mode at the operating point N4.
[0067] The method for switching the operating mode of a hybrid power system according to an embodiment of the present application takes into account the potential reduction in output capacity caused by engine start and clutch closing during subsequent switching processes (such as Figure 3 and Figure 4 's situation), and thus makes a switching decision different from that of the traditional method (i.e., selects a different operating mode for the target operating point) to ensure that a sufficient margin of torque capability can be provided in any case.
[0068] In addition, as described above, the present application can also be implemented as a computer-readable storage medium in which there is stored for causing a computer to execute as Figure 2The program of the method shown herein. Herein, as a computer-readable storage medium, various types of computer-readable storage media such as disk media (e.g., magnetic disks, optical discs, etc.), card media (e.g., memory cards, optical cards, etc.), semiconductor memory media (e.g., ROM, non-volatile memories, etc.), tape media (e.g., magnetic tapes, cassette tapes, etc.) can be adopted.
[0069] This application can also be implemented as a computer program product, which includes a computer program that, when executed by a processor, implements the program of the method as Figure 2 shown herein.
[0070] In applicable cases, various embodiments provided by this application can be implemented using hardware, software, or a combination of hardware and software. Moreover, in applicable cases, without departing from the scope of this application, various hardware components and / or software components described herein can be combined into composite components including software, hardware, and / or both. In applicable cases, without departing from the scope of this application, various hardware components and / or software components described herein can be divided into sub-components including software, hardware, or both. Additionally, in applicable cases, it is contemplated that software components can be implemented as hardware components, and vice versa.
[0071] The software (such as program code and / or data) according to this application can be stored on one or more computer-readable storage media or made into one or more computer program products. It is also contemplated that one or more general-purpose or special-purpose computers and / or computer systems connected via a network and / or in other ways can be used to implement the software identified herein. In applicable cases, the order of the various steps described herein can be changed, combined into composite steps, and / or divided into sub-steps to provide the features described herein.
[0072] The embodiments and examples presented herein are provided to best illustrate the embodiments in accordance with this application and its specific applications, and thereby enable those skilled in the art to implement and use this application. However, those skilled in the art will know that the above description and examples are provided only for ease of illustration and exemplification. The presented description is not intended to cover all aspects of this application or limit this application to the precise forms disclosed.
Claims
1. A method for switching an operating mode of a hybrid power system, the method comprising: obtaining a current speed and a current required torque at the current speed and a current torque capability of each operating mode; calculating a predicted speed and a predicted required torque at the predicted speed and a predicted torque capacity for each operating mode; determining whether a mode switch is required according to a difference between a current torque capacity of a current mode and the current required torque and a difference between a predicted torque capacity of the current mode and the predicted required torque; as well as In response to determining that a mode switch is required, a target mode is selected based on the number of potentially available modes.
2. The method of claim 1, wherein: Determining whether mode switching is required according to the difference between the current torque capacity of the current mode and the current required torque and the difference between the predicted torque capacity of the current mode and the predicted required torque includes: If the difference between the current torque capacity of the current mode and the current required torque is greater than a first threshold and the difference between the predicted torque capacity of the current mode and the predicted required torque is greater than a second threshold, no mode switching is required, and the second threshold corresponds to the torque lost by the current mode during the mode switching process.
3. The method of claim 2, wherein: The current torque capacity of the potentially available mode is greater than the current torque capacity of the current mode, and the predicted torque capacity of the potentially available mode is greater than the predicted torque capacity of the current mode.
4. The method of claim 2, wherein: A difference between the current torque capacity of the potentially available mode and the current required torque is greater than the first threshold.
5. The method of claim 2, wherein: A difference between the predicted torque capacity of the potentially available mode and the predicted required torque is greater than the second threshold.
6. The method according to any one of claims 3 to 5, wherein: The target mode is selected based on the number of potentially available modes including: If the number of the potentially available modes is greater than 1, the potentially available mode with the best efficiency is selected as the target mode.
7. The method according to any one of claims 3 to 5, wherein: The target mode is selected based on the number of potentially available modes including: If the number of the potentially available modes is 0, the mode having the largest value of the predicted torque capacity is selected as the target mode.
8. A hybrid power system, the system comprising: Multiple power sources connected to each other; a drive shaft coupled to the plurality of power sources; and a controller configured to execute the method according to any one of claims 1-7.
9. The hybrid power system according to claim 8, wherein: The plurality of power sources include an engine and a power battery, the engine being connected to the power battery via a generator.
10. A computer-readable storage medium, the computer-readable storage medium comprising instructions, the instructions executing the method according to any one of claims 1 to 7.
11. A computer program product, comprising instructions, which when executed, execute the method according to any one of claims 1 to 7.