Hybrid vehicle series-parallel driving mode switching control method and control device

Abstract

This invention discloses a control method and control device for switching between series and parallel drive modes in a hybrid electric vehicle. The method includes the following steps: obtaining the target power demand of the hybrid electric vehicle and the available drive power of the hybrid electric vehicle during the clutch engagement phase; determining whether the target power demand and the available drive power meet preset conditions; if the target power demand and the available drive power meet the preset conditions, obtaining the current operating state of the hybrid electric vehicle; and generating a control strategy set based on the current operating state, wherein the control strategy set is used to control whether the hybrid electric vehicle switches from a series drive mode to a parallel drive mode. This invention solves the technical problem of insufficient available drive power of the drive motor during the switching between series and parallel modes in related technologies.

Description

Technical Field

[0001] This invention relates to the field of vehicle control technology, and more specifically, to a control method and control device for switching between series and parallel drive modes in a hybrid electric vehicle. Background Technology

[0002] With the advent of the global energy revolution and the increasing scarcity of oil resources, coupled with increasingly stringent fuel consumption regulations, reducing fuel consumption in traditional pure internal combustion engine-driven vehicles is becoming increasingly costly and difficult. Hybrid vehicles, aided by electric motors, have great potential for reducing fuel consumption. The P2 configuration, represented by European manufacturers, and the dual-motor planetary gear power-split configuration, represented by Toyota, have already achieved mass production and good fuel economy, gaining favor among consumers. However, the P2 configuration, which includes a C0 motor and a three-clutch module, has a complex structure and requires high-level clutch control. The dual-motor planetary gear power-split configuration involves the control of three motors, which is quite complex, and there is almost no documented control method for the dual-motor planetary gear power-split configuration in existing technologies.

[0003] The dual-motor series-parallel hybrid configuration has proven to be a relatively easy-to-implement hybrid powertrain configuration in recent years, and it also allows for convenient switching between HEV and PHEV modes. At low and medium speeds, the drive motor drives the vehicle while the engine is off or operating in its economical power generation range, a series drive mode. At medium and high speeds, the clutch engages, and the engine directly drives the vehicle at a fixed speed ratio, a parallel drive mode. Furthermore, the engine load can be adjusted via the drive motor, ensuring the engine still operates in a low-fuel-consumption economic range. Through the implementation of this scheme, a fuel consumption of less than 4L per 100km can be achieved under NEDC conditions.

[0004] Due to the variable operating conditions of the vehicle, frequent switching between series and parallel drive modes is involved. Therefore, a reasonable timing for this switching is crucial to ensure that both fuel consumption and driving smoothness are maintained during the transition. In series drive mode, the dual-motor hybrid configuration operates independently, with engine speed decoupled from vehicle speed. This allows the engine to operate at higher speeds, driving the generator to produce more electricity for the drive motor. In parallel drive mode, the dual-motor hybrid configuration operates jointly, with engine speed and vehicle speed having a fixed speed ratio. The maximum available driving force of the engine equals the maximum torque at that engine speed.

[0005] When switching from series drive mode to parallel drive mode, the engine operating point is first adjusted. The target engine torque is equal to the torque in parallel drive mode, and the target engine speed is equal to the engine speed in parallel drive mode. During the engine operating point adjustment phase, the engine speed switches to parallel speed, and the engine torque switches to parallel torque. As a result, the engine operating point is no longer the same as in series mode, causing a change in the generator driven by the engine. Under certain operating conditions, the generator output may not be sufficient to meet the needs of the drive motor after the engine operating point adjustment. If the switching continues at this point, the available drive power of the drive motor will be insufficient, leading to reduced power and affecting drivability. Summary of the Invention

[0006] This invention provides a control method and control device for switching between series and parallel drive modes in hybrid electric vehicles, so as to at least solve the technical problem of insufficient available drive power of the drive motor when switching between series and parallel modes in related technologies.

[0007] According to one aspect of the present invention, a control method for switching between series and parallel drive modes of a hybrid electric vehicle is provided, comprising the following steps: obtaining the target power demand of the hybrid electric vehicle and the available drive power of the hybrid electric vehicle during the clutch engagement phase; determining whether the target power demand and the available drive power meet preset conditions; if the target power demand and the available drive power meet the preset conditions, obtaining the current operating state of the hybrid electric vehicle, the current operating state including: the operating state in which the hybrid electric vehicle is about to switch from series drive mode to parallel drive mode and the operating state in which the hybrid electric vehicle is operating in series drive mode; and generating a control strategy set based on the current operating state, wherein the control strategy set is used to control whether the hybrid electric vehicle switches from series drive mode to parallel drive mode.

[0008] Optionally, when the target power demand and available drive power meet preset conditions, and the current operating state is that the hybrid vehicle is about to switch from series drive mode to parallel drive mode, a first control strategy is generated. The first control strategy is used to terminate the hybrid vehicle's switch from series drive mode to parallel drive mode.

[0009] Optionally, the method includes: generating a second control strategy when the target power demand and available drive power meet preset conditions, and the current operating state is that the hybrid vehicle is operating in series drive mode, the second control strategy being used to prevent the hybrid vehicle from switching from series drive mode to parallel drive mode.

[0010] Optionally, before obtaining the target power demand of the hybrid electric vehicle and the available drive power of the hybrid electric vehicle during the clutch engagement phase, the process includes: obtaining the adjustment time required for the engine speed to adjust from the series speed to the parallel speed and the current power demand of the hybrid electric vehicle; determining the target power demand based on the adjustment time and the current power demand; when the engine speed is at the parallel speed, obtaining the generator power output and the available discharge power of the power battery during the adjustment time; determining the available energy power of the drive motor before the clutch engagement ends based on the generator power output and the available discharge power; obtaining the efficiency of the drive motor at the target power demand after the adjustment time; and determining the available drive power based on the available energy power and the efficiency.

[0011] Optionally, determining the target demand power based on the adjustment time and the current demand power includes: filtering the current demand power with an average value over a preset period to obtain a filtered first demand power; performing a difference operation between the first demand power and the current demand power to obtain a first calculation result; determining the rate of change of the current demand power based on the first calculation result; multiplying the rate of change by the adjustment time to obtain a first product; and determining the target demand power based on the first product and the current demand power.

[0012] Optionally, before obtaining the efficiency of the drive motor under the target power requirement, the process includes: obtaining the speed change rate of the drive motor; multiplying the speed change rate by the adjustment time to obtain a second product; determining the second speed of the drive motor after the adjustment time based on the second product and the current first speed of the drive motor; obtaining the torque of the drive motor under the target power requirement; and determining the efficiency based on the second speed and torque.

[0013] Optionally, determining whether the target demand power and the available drive power meet preset conditions includes: determining whether the target demand power is greater than the sum of the available drive power and the hysteresis value; if the target demand power is greater than the sum of the available drive power and the hysteresis value, determining that the target demand power and the available drive power meet preset conditions.

[0014] Optionally, the method further includes: determining whether the target power demand is less than the difference between the available drive power and the hysteresis value; if the target power demand is less than the difference between the available drive power and the hysteresis value, allowing the hybrid vehicle to switch from series drive mode to parallel drive mode.

[0015] According to another aspect of the present invention, a control device for switching between series and parallel drive modes of a hybrid electric vehicle is also provided, comprising: a first acquisition module for acquiring the target power demand of the hybrid electric vehicle and the available drive power of the hybrid electric vehicle during the clutch engagement phase; a judgment module for judging whether the target power demand and the available drive power meet preset conditions; a second acquisition module for acquiring the current operating state of the hybrid electric vehicle when the target power demand and the available drive power meet the preset conditions, the current operating state including: the operating state in which the hybrid electric vehicle is about to switch from series drive mode to parallel drive mode and the operating state in which the hybrid electric vehicle is operating in series drive mode; and a control module for generating a control strategy set based on the current operating state, wherein the control strategy set is used to control whether the hybrid electric vehicle switches from series drive mode to parallel drive mode.

[0016] According to another aspect of the present invention, a vehicle is also provided, which has a series drive mode and a parallel drive mode, and the vehicle is controlled by the above-described control method for switching between series and parallel drive modes of a hybrid electric vehicle.

[0017] In this embodiment of the invention, by obtaining the target power demand of the hybrid electric vehicle and the available drive power of the hybrid electric vehicle during the clutch engagement phase, it is determined whether the target power demand and the available drive power meet preset conditions. If the target power demand and the available drive power meet the preset conditions, the current operating state of the hybrid electric vehicle is obtained. Based on the current operating state, a control strategy set is generated. The control strategy set is used to control whether the hybrid electric vehicle switches from a series drive mode to a parallel drive mode. This ensures that when the target power demand and the available drive power meet the preset conditions, the hybrid electric vehicle switches from a series drive mode to a parallel drive mode based on its current operating state. This avoids the problem of weakened power performance caused by continuing to switch from a series drive mode to a parallel drive mode when the available energy of the hybrid electric vehicle is insufficient in the current operating state. This solves the technical problem of insufficient available drive power of the drive motor when switching between series and parallel modes in related technologies. Attached Figure Description

[0018] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings:

[0019] Figure 1 This is a hardware structure block diagram of an electronic device for a vehicle according to one embodiment of the present invention;

[0020] Figure 2This is a flowchart of a control method for switching series-parallel drive modes of a hybrid electric vehicle according to an optional embodiment of the present invention;

[0021] Figure 3 This is a structural block diagram of a control device for switching series and parallel drive modes of a hybrid electric vehicle according to one embodiment of the present invention;

[0022] Figure 4 This is a structural block diagram of the power system of a hybrid electric vehicle according to one optional embodiment of the present invention.

[0023] The above figures include the following reference numerals:

[0024] 1. Engine; 2. Generator; 3. Clutch; 4. Drive motor; 5. Differential; 6. Reduction gear. Detailed Implementation

[0025] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0026] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0027] According to one embodiment of the present invention, an embodiment of a control method for switching series-parallel drive modes of a hybrid electric vehicle is provided. It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Furthermore, although a logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in a different order than that shown here.

[0028] This method embodiment can be executed in an electronic device or similar computing device that includes memory and a processor within a vehicle. Taking an electronic device running in a vehicle as an example, such as... Figure 1 As shown, the vehicle's electronic devices may include one or more processors 102 (processors may include, but are not limited to, central processing units (CPUs), graphics processing units (GPUs), digital signal processing (DSP) chips, microprocessors (MCUs), programmable logic devices (FPGAs), neural network processors (NPUs), tensor processors (TPUs), artificial intelligence (AI) type processors, etc.) and a memory 104 for storing data. Optionally, the vehicle's electronic devices may also include a transmission device 106 for communication functions, an input / output device 108, and a display 110. Those skilled in the art will understand that... Figure 1 The structures shown are for illustrative purposes only and do not limit the structure of the electronic devices in the vehicle described above. For example, the electronic devices in a vehicle may include more or fewer components than those described above, or have a different configuration than those described above.

[0029] The memory 104 can be used to store computer programs, such as application software programs and modules, like the computer program corresponding to the information processing method in this embodiment of the invention. The processor 102 executes various functional applications and data processing by running the computer program stored in the memory 104, thereby implementing the aforementioned information processing method. The memory 104 may include high-speed random access memory and may also include non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memory. In some instances, the memory 104 may further include memory remotely located relative to the processor 102, and these remote memories can be connected to the mobile terminal via a network. Examples of such networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof.

[0030] The transmission device 106 is used to receive or send data via a network. Specific examples of the network described above may include a wireless network provided by the mobile terminal's communication provider. In one example, the transmission device 106 includes a Network Interface Controller (NIC), which can connect to other network devices via a base station to communicate with the Internet. In another example, the transmission device 106 may be a Radio Frequency (RF) module used for wireless communication with the Internet.

[0031] Display 110 may be, for example, a touchscreen liquid crystal display (LCD). This LCD allows a user to interact with the user interface of the mobile terminal. In some embodiments, the mobile terminal has a graphical user interface (GUI), which allows the user to interact with the GUI via finger contact and / or gestures on a touch-sensitive surface. The human-computer interaction functions may optionally include: creating web pages, drawing, word processing, creating electronic documents, playing games, video conferencing, instant messaging, sending and receiving emails, a call interface, playing digital video, playing digital music, and / or web browsing, etc. Executable instructions for performing the above-mentioned human-computer interaction functions are configured / stored in one or more processor-executable computer program products or readable storage media.

[0032] This embodiment provides a control method for switching between series and parallel drive modes in a hybrid electric vehicle using electronic devices operating in the aforementioned vehicle. Figure 2 This is a flowchart of a control method for switching series-parallel drive modes in a hybrid electric vehicle according to one embodiment of the present invention, such as... Figure 2 As shown, the process includes the following steps:

[0033] Step S21: Obtain the target power demand of the hybrid vehicle and the available drive power of the hybrid vehicle during the clutch engagement phase.

[0034] Step S22: Determine whether the target power requirement and the available drive power meet the preset conditions;

[0035] Step S23: Under the condition that the target power demand and the available drive power meet the preset conditions, obtain the current working state of the hybrid vehicle. The current working state includes: the working state of the hybrid vehicle about to switch from series drive mode to parallel drive mode and the working state of the hybrid vehicle working in series drive mode.

[0036] Step S24: Based on the current working state, generate a control strategy set, wherein the control strategy set is used to control whether the hybrid vehicle switches from series drive mode to parallel drive mode.

[0037] By applying the technical solution of this embodiment, the target power demand of the hybrid electric vehicle and the available drive power of the hybrid electric vehicle during the clutch engagement phase are obtained. It is then determined whether the target power demand and the available drive power meet preset conditions. If the target power demand and the available drive power meet the preset conditions, the current operating state of the hybrid electric vehicle is obtained. Based on the current operating state, a control strategy set is generated. The control strategy set is used to control whether the hybrid electric vehicle switches from series drive mode to parallel drive mode. This ensures that the target power demand and the available drive power meet the preset conditions, and then controls whether the hybrid electric vehicle switches from series drive mode to parallel drive mode based on the current operating state of the hybrid electric vehicle. This avoids the problem of weakened power of the hybrid electric vehicle caused by continuing to switch from series drive mode to parallel drive mode when the available energy of the hybrid electric vehicle is insufficient in the current operating state. This solves the technical problem of insufficient available drive power of the drive motor when switching between series mode and parallel mode in related technologies.

[0038] Optionally, the method includes: generating a first control strategy when the target power demand and available drive power meet preset conditions, and the current operating state is that the hybrid vehicle is about to switch from series drive mode to parallel drive mode. The first control strategy is used to terminate the switch of the hybrid vehicle from series drive mode to parallel drive mode. Specifically, when the target power demand and available drive power meet preset conditions, it means that the available energy of the vehicle is insufficient to allow the hybrid vehicle to switch from series drive mode to parallel drive mode. If the hybrid vehicle is currently in the operating state of about to switch from series drive mode to parallel drive mode, the switch of the hybrid vehicle from series drive mode to parallel drive mode is terminated, and the hybrid vehicle operates in series drive mode. This further avoids the problem of weakened vehicle power caused by continuing to switch when the available energy of the vehicle is insufficient when it is in the operating state of about to switch from series drive mode to parallel drive mode.

[0039] Optionally, the method further includes: generating a second control strategy when the target power demand and available drive power meet preset conditions, and the current operating state is that the hybrid vehicle is operating in series drive mode. The second control strategy is used to prohibit the hybrid vehicle from switching from series drive mode to parallel drive mode. In this embodiment, when the target power demand and available drive power meet preset conditions, since the available energy of the vehicle is insufficient to allow the hybrid vehicle to switch from series drive mode to parallel drive mode, the hybrid vehicle is prohibited from switching from series drive mode to parallel drive mode when the current operating state of the hybrid vehicle is operating in series drive mode. This avoids the problem of weakened vehicle power caused by switching the hybrid vehicle from series drive mode to parallel drive mode when the available energy of the vehicle is insufficient.

[0040] Optionally, before obtaining the target power demand of the hybrid vehicle and the available drive power of the hybrid vehicle during the clutch engagement phase, the following steps are included:

[0041] Step S31: Obtain the adjustment time required for the engine speed to be adjusted from the series speed to the parallel speed, and the current power demand of the hybrid vehicle;

[0042] In this step, the adjustment time is continuously calculated when the hybrid vehicle is about to switch from series drive mode to parallel drive mode, and when it is operating in series drive mode. The current surplus charging power of the power battery is calculated as "available charging power of the power battery + current mechanical power of the engine * current generator efficiency - current mechanical power of the drive motor / current driving efficiency of the drive motor". Here, the charging power of the power battery is negative, and the discharging power is positive. When the hybrid vehicle is driven by the drive motor, the mechanical power of the drive motor is positive; when the drive motor is regenerative braking, the mechanical power of the drive motor is negative. The available speed-regulating power of the generator is obtained by looking up the current surplus charging power of the power battery in a table. The relevant values ​​in this example are shown in the table below.

[0043]

[0044] The change in kinetic energy of the engine and generator combination is obtained by subtracting their kinetic energy at the current speed from the kinetic energy at the target parallel speed. The available speed-regulating power of the generator is then compared with this change in kinetic energy to obtain the first time (Se2PaSpdChgTRaw) required for engine speed regulation. Multiplying this first time (Se2PaSpdChgTRaw) by 1.2 and adding the second time (Se2PaClchClsT) required for clutch engagement gives the adjustment time (Se2PaTAll) required from the current moment until clutch engagement ends. When the hybrid vehicle switches from series drive mode to parallel drive mode, the adjustment time (Se2PaTAll) gradually shortens as the series engine speed gradually approaches the parallel engine speed. Specifically, the second time (Se2PaClchClsT) required for clutch engagement is approximately 0.5 seconds.

[0045] Step S32: Determine the target power demand based on the adjustment time and the current power demand.

[0046] Step S33: When the engine speed is at the parallel speed, obtain the generator power output and the available discharge power of the power battery during the adjustment time.

[0047] Specifically, the mechanical power of the engine at the target parallel speed and target parallel torque, and the power generation efficiency of the generator at the target parallel speed and target parallel torque are multiplied to obtain the generator power generation GmPwrPa at the target parallel speed and target parallel torque of the engine. The current available discharge energy of the power battery is compared with the adjustment time Se2PaTAll to obtain the ratio result. Then, it is compared with the available discharge power of the power battery. The minimum value between the ratio result and the available discharge power of the power battery is taken to obtain the available discharge power BmsPwrPa of the power battery within the adjustment time Se2PaTAll.

[0048] Step S34: Based on the power generation and available discharge power, determine the available energy power of the drive motor before the clutch engagement ends;

[0049] In this step, the generated power GmPwrPa is added to the available discharge power BmsPwrPa to obtain the available energy power of the drive motor before the clutch engagement ends.

[0050] Step S35: Obtain the efficiency of the drive motor under the target power requirement after the adjustment time;

[0051] Step S36: Determine the available drive power based on available energy power and efficiency.

[0052] Specifically, by multiplying the available energy power by the efficiency of the drive motor at the target power requirement, the available drive power of the drive motor before the clutch engagement ends can be obtained.

[0053] In this embodiment, the accuracy and reliability of the obtained available drive power are improved by determining the available drive power through the above steps.

[0054] Optionally, determining the target demand power based on the adjustment time and the current demand power includes: filtering the current demand power using an average value over a preset period to obtain a filtered first demand power; performing a difference operation between the first demand power and the current demand power to obtain a first calculation result; determining the rate of change of the current demand power based on the first calculation result; multiplying the rate of change by the adjustment time to obtain a first product; and determining the target demand power based on the first product and the current demand power. Preferably, the preset period is 10 periods. By filtering the current demand power using an average value over 10 periods to obtain the filtered first demand power, performing a difference operation between the current demand power and the first demand power over these 10 periods to obtain a first calculation result, which is the rate of change of the current demand power, multiplying the rate of change by the adjustment time Se2PaTAll to obtain a first product, and adding the first product to the current demand power, the target demand power after the adjustment time Se2PaTAll is obtained. This method of determining the target demand power is more accurate.

[0055] Optionally, before obtaining the efficiency of the drive motor at the target power requirement, the following steps are included:

[0056] Step S51: Obtain the rate of change of the drive motor speed;

[0057] Specifically, the drive motor speed is filtered by the average value of 20 calculation cycles. For the drive motor speed after average value filtering, the difference between the drive motor speed before filtering and the drive motor speed after filtering is calculated over 10 calculation cycles to obtain the speed change rate of the drive motor.

[0058] Step S52: Multiply the rate of change of rotational speed by the adjustment time to obtain the second product;

[0059] Step S53: Based on the second product and the first speed of the current drive motor, determine the second speed of the drive motor after the adjustment time;

[0060] In this step, the second product is added to the first speed of the current drive motor to obtain the second speed TmSpdF of the drive motor after an integer time.

[0061] Step S54: Obtain the torque of the drive motor under the target power requirement;

[0062] Specifically, the torque TmTrqF of the drive motor after the adjustment time Se2PaTAll is obtained by using the power DrvPwrReqFu*9550 / TmSpdF of the drive motor after the adjustment time Se2PaTAll.

[0063] Step S55: Determine the efficiency based on the second rotational speed and torque.

[0064] In this step, the efficiency value of the drive motor under the future power DrvPwrReqFu can be obtained by consulting the drive motor efficiency table using the second speed TmSpdF and torque TmTrqF of the drive motor. This ensures the reliability and accuracy of the obtained efficiency value.

[0065] Optionally, determining whether the target required power and available drive power meet preset conditions includes: determining whether the target required power is greater than the sum of the available drive power and the hysteresis value; if the target required power is greater than the sum of the available drive power and the hysteresis value, determining that the target required power and available drive power meet the preset conditions. Specifically, if the target required power is greater than the available drive power, it is considered that if the hybrid vehicle continues to switch from series drive mode to parallel drive mode, the overall vehicle drive power will be limited and reduced. The hysteresis value is set to prevent the switching termination signal from jumping back and forth. If the target required power is greater than the sum of the available drive power and the hysteresis value, determining whether the target required power and available drive power meet the preset conditions, and terminating the switch when the hybrid vehicle is about to switch from series drive mode to parallel drive mode, and prohibiting the switch when the hybrid vehicle is operating in series drive mode, further avoids the problem of weakened vehicle power caused by switching from series drive mode to parallel drive mode when the vehicle's available energy is insufficient. The hysteresis value DltPwr is obtained by looking up a table using vehicle speed and the available discharge power of the power battery. The higher the vehicle speed, the larger the hysteresis value DltPwr, because the driver's sensitivity to power reduction decreases at high speeds. The hysteresis values ​​DltPwr at different vehicle speeds are shown in the table below:

[0066]

[0067] Optionally, the method further includes: determining whether the target power demand is less than the difference between the available drive power and the hysteresis value; and allowing the hybrid electric vehicle to switch from series drive mode to parallel drive mode if the target power demand is less than the difference between the available drive power and the hysteresis value. In this embodiment, when the target power demand is less than the difference between the available drive power and the hysteresis value, it means that the available energy of the vehicle is sufficient to allow the hybrid electric vehicle to switch from series drive mode to parallel drive mode. At this time, the hybrid electric vehicle is allowed to perform the switching operation from series drive mode to parallel drive mode, which solves the technical problem of insufficient available drive power of the drive motor when switching between series and parallel modes in related technologies.

[0068] According to another specific embodiment of this application, a control device for switching between series and parallel drive modes in a hybrid electric vehicle is also provided. For example... Figure 3 As shown, the control device for switching between series and parallel drive modes in a hybrid electric vehicle includes: a first acquisition module 42, a judgment module 44, a second acquisition module 46, and a control module 48. The first acquisition module 42 acquires the target power demand of the hybrid electric vehicle and the available drive power during clutch engagement. The judgment module 44 determines whether the target power demand and available drive power meet preset conditions. The second acquisition module 46 acquires the current operating state of the hybrid electric vehicle when the target power demand and available drive power meet the preset conditions. The current operating state includes: the hybrid electric vehicle is about to switch from series drive mode to parallel drive mode, and the hybrid electric vehicle is operating in series drive mode. The control module 48 generates a control strategy set based on the current operating state, wherein the control strategy set is used to control whether the hybrid electric vehicle switches from series drive mode to parallel drive mode.

[0069] In this embodiment, by acquiring the target power demand of the hybrid electric vehicle and the available drive power of the hybrid electric vehicle during the clutch engagement phase, it is determined whether the target power demand and the available drive power meet preset conditions. If the target power demand and the available drive power meet the preset conditions, the current operating state of the hybrid electric vehicle is acquired. Based on the current operating state, a control strategy set is generated. The control strategy set is used to control whether the hybrid electric vehicle switches from series drive mode to parallel drive mode. This ensures that when the target power demand and the available drive power meet the preset conditions, the hybrid electric vehicle switches from series drive mode to parallel drive mode based on the current operating state. This avoids the problem of weakened power performance caused by continuing to switch from series drive mode to parallel drive mode when the available energy of the hybrid electric vehicle is insufficient in the current operating state. This solves the technical problem of insufficient available drive power of the drive motor when switching between series and parallel modes in related technologies.

[0070] According to another specific embodiment of this application, a hybrid electric vehicle is also provided. This hybrid electric vehicle has a dual-motor hybrid configuration, and is controlled using the series-parallel drive mode switching control method described in the above embodiments. Figure 4The diagram shows a structural block diagram of the power system of a hybrid electric vehicle according to this application. Engine 1 and generator 2 are connected via reduction gear 6, and engine 1 and drive motor 4 are connected via clutch 3. The output of drive motor 4 is connected to differential 5. When clutch 3 is disengaged, engine 1 drives generator 2 to generate electricity. The electricity generated by generator 2 and the electricity from the power battery are supplied to drive motor 4, which drives the vehicle forward. In this series drive mode, the vehicle has only one drive source: drive motor 4. When clutch 3 is engaged, the torque output by engine 1 directly drives the vehicle forward. Simultaneously, drive motor 4 can also utilize the power battery's charge to drive the vehicle forward. In this parallel drive mode, the vehicle has two drive sources: engine 1 and drive motor 4. In series drive mode, the vehicle controller calculates the target output power of the engine based on the current operating conditions of the vehicle, the capabilities of engine 1 and generator 2, and the charging and discharging capabilities of the power battery. This target output power is ultimately converted into target engine speed and target engine torque. The target engine torque is achieved by the engine itself, while the target engine speed is achieved by the generator adjusting its own torque. Once the engine speed stabilizes, the generator torque equals the engine torque in magnitude but opposite in sign; therefore, the generator power equals the engine power. Multiplying the generator's output power by its current generating efficiency yields the generator's output power at that operating point. Adding the generator's output power to the available discharge power of the power battery gives the maximum available power of the drive motor. In parallel drive mode, the engine speed and vehicle speed have a fixed speed ratio. The driver's required drive torque is jointly provided by engine 1 and drive motor 4. When the driver's required drive torque does not exceed the maximum torque of engine 1 at the current speed, the entire required torque is provided by engine 1. When the driver's required drive torque exceeds the maximum torque of engine 1 at the current speed, the portion exceeding the maximum torque is provided by drive motor 4. In parallel mode, the maximum drive power of the drive motor should be less than the smaller of the maximum discharge power of the power battery and the maximum drive power of the drive motor at its current speed. Specifically, the switching from series drive mode to parallel drive mode in a hybrid electric vehicle (HEV) is divided into three stages: the switching stage, the clutch engagement stage, and the torque alternation stage. During the switching stage, the engine speed is adjusted from the target speed in the current series mode to the engine speed in the parallel mode, the engine torque is adjusted from the target torque in the current series mode to the engine torque in the parallel mode, and the generator output power changes based on the engine power change.During the transition from series drive mode to parallel drive mode in a hybrid electric vehicle, the clutch is not engaged, and the vehicle remains in series drive mode. During this transition, the output power of generator 2 changes, resulting in a situation where the output power of generator 2 plus the discharge power of the power battery is insufficient to meet the power consumption of drive motor 4. During clutch engagement, the vehicle remains in series drive mode, and the available power of drive motor 4 is still equal to the output power of generator 2 plus the maximum discharge power of the power battery. During torque alternation, the vehicle gradually transitions from being driven by drive motor 4 to being driven by both drive motor 4 and engine 1. Generator 2 gradually reduces its negative torque generation to release engine torque, while drive motor 4 simultaneously reduces its torque by the same amount to maintain overall drive torque balance. This involves both energy and torque transfer. During the switching between series and parallel drive modes in a hybrid electric vehicle (HEV), the reduction in driving force primarily occurs during the transition from series to parallel drive mode and the engagement of clutch 3. If no reduction in driving force occurs during these transitions, the torque alternation phase will also be unaffected. Conversely, if a reduction in driving force does occur during these transitions, the torque alternation phase will also be affected. Therefore, it is necessary to assess the vehicle's energy balance during the transitions and clutch 3 engagement phases to determine if a reduction in driving power is imminent. If a reduction in driving power is predicted, the parallel switch should be terminated and the vehicle switched back to series drive mode to ensure smooth driving performance. In this embodiment, by judging whether the switching from series to parallel drive mode is possible from the perspective of whether the available energy of the vehicle meets the future power requirements of the drive motor during the engine operating point transfer stage and clutch engagement stage of the series-to-parallel switching, the switching process is terminated in time and the vehicle is switched back to the series drive mode when the calculated available energy of the vehicle does not meet the future power requirements of the drive motor. This avoids the problem of weakened vehicle power caused by continuing to switch when the available energy of the vehicle is insufficient during the current series-to-parallel switching process. When the insufficient available energy of the vehicle is detected, the switching process is terminated in time, ensuring the power of the vehicle and solving the technical problem of insufficient available drive power of the drive motor when switching between series and parallel modes in related technologies.

[0071] According to another specific embodiment of this application, a computer-readable storage medium is also provided, the computer-readable storage medium including a stored program, wherein the program controls the computer-readable storage medium during runtime, and the device in which it is located executes the control method for switching the series-parallel drive mode of a hybrid electric vehicle in the above embodiment.

[0072] According to another specific embodiment of this application, a vehicle is also provided, which has a series drive mode and a parallel drive mode, and the vehicle is controlled by the control method for switching between series and parallel drive modes of hybrid electric vehicles in the above embodiments.

[0073] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods according to the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) and includes several instructions to cause a terminal device (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods described in the various embodiments of the present invention.

[0074] It should be noted that the above modules can be implemented by software or hardware. For the latter, they can be implemented in the following ways, but are not limited to: all the above modules are located in the same processor; or, the above modules are located in different processors in any combination.

[0075] Embodiments of the present invention also provide a processor configured to run a computer program to perform the steps in any of the above method embodiments.

[0076] The sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0077] In the above embodiments of the present invention, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0078] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. The device embodiments described above are merely illustrative; for example, the division of units can be a logical functional division, and in actual implementation, there may be other division methods. For instance, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual coupling, direct coupling, or communication connection may be through some interfaces; the indirect coupling or communication connection between units or modules may be electrical or other forms.

[0079] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0080] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0081] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, read-only memory (ROM), random access memory (RAM), portable hard drives, magnetic disks, or optical disks.

[0082] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A control method for switching between series and parallel drive modes in a hybrid electric vehicle, characterized in that, The method includes the following steps: The target power requirement of the hybrid electric vehicle and the available drive power of the hybrid electric vehicle during the clutch engagement phase are obtained. Determine whether the target power requirement and the available drive power meet preset conditions; When the target required power and the available drive power meet the preset conditions, the current operating state of the hybrid vehicle is obtained. The current operating state includes: the operating state in which the hybrid vehicle is about to switch from series drive mode to parallel drive mode and the operating state in which the hybrid vehicle is operating in series drive mode. Based on the current operating state, a control strategy set is generated, wherein the control strategy set is used to control whether the hybrid vehicle switches from the series drive mode to the parallel drive mode; The method includes: When the target required power and the available drive power meet the preset conditions, and the current working state is when the hybrid vehicle is about to switch from the series drive mode to the parallel drive mode, a first control strategy is generated. The first control strategy is used to terminate the hybrid vehicle from switching from the series drive mode to the parallel drive mode. When the target required power and the available drive power meet the preset conditions, and the current working state is that the hybrid vehicle is working in the series drive mode, a second control strategy is generated. The second control strategy is used to prevent the hybrid vehicle from switching from the series drive mode to the parallel drive mode. Before obtaining the target power demand of the hybrid vehicle and the available drive power of the hybrid vehicle during the clutch engagement phase, the process includes: The adjustment time required for the engine speed to be adjusted from the series speed to the parallel speed, and the current power demand of the hybrid vehicle are obtained. The target power demand is determined based on the adjustment time and the current power demand. When the engine speed is at the parallel speed, the generator power output and the available discharge power of the power battery during the adjustment time are obtained. Based on the power generation and the available discharge power, determine the available energy power of the drive motor before the clutch engagement ends; After obtaining the adjustment time, the efficiency of the drive motor under the target power requirement; The available drive power is determined based on the available energy power and the efficiency.

2. The method of claim 1, wherein, Determining the target power demand based on the adjustment time and the current power demand includes: The current demand power is filtered by the average value of a preset period to obtain the filtered first demand power; Perform a difference operation between the first required power and the current required power to obtain the first calculation result; Based on the first calculation result, determine the rate of change of the current demand power; Multiply the rate of change by the adjustment time to obtain the first product; The target power demand is determined based on the first product and the current power demand.

3. The method of claim 1, wherein, Before obtaining the efficiency of the drive motor at the target power requirement, the following steps are included: Obtain the rate of change of the rotational speed of the drive motor; Multiply the rate of change of rotational speed by the adjustment time to obtain a second product; Based on the second product and the current first speed of the drive motor, determine the second speed of the drive motor after the adjustment time; Obtain the torque of the drive motor at the target power requirement; The efficiency is determined based on the second rotational speed and the torque.

4. The method of claim 1, wherein, Determining whether the target power requirement and the available drive power meet preset conditions includes: Determine whether the target power requirement is greater than the sum of the available drive power and the hysteresis value; If the target required power is greater than the sum of the available drive power and the hysteresis value, it is determined that the target required power and the available drive power satisfy the preset condition.

5. The method of claim 4, wherein, The method further includes: Determine whether the target power requirement is less than the difference between the available drive power and the hysteresis value; When the target power demand is less than the difference between the available drive power and the hysteresis value, the hybrid vehicle is allowed to switch from the series drive mode to the parallel drive mode.

6. A control device for switching series and parallel drive modes in a hybrid electric vehicle, characterized in that, include: The first acquisition module acquires the target power requirement of the hybrid electric vehicle and the available drive power of the hybrid electric vehicle during the clutch engagement phase. The judgment module determines whether the target required power and the available drive power meet preset conditions; The second acquisition module acquires the current operating state of the hybrid vehicle when the target required power and the available driving power meet the preset conditions. The current operating state includes: the operating state of the hybrid vehicle about to switch from series drive mode to parallel drive mode and the operating state of the hybrid vehicle operating in series drive mode. The control module generates a control strategy set based on the current working state, wherein the control strategy set is used to control whether the hybrid vehicle switches from the series drive mode to the parallel drive mode; When the target required power and the available drive power meet the preset conditions, and the current working state is when the hybrid vehicle is about to switch from the series drive mode to the parallel drive mode, a first control strategy is generated. The first control strategy is used to terminate the hybrid vehicle from switching from the series drive mode to the parallel drive mode. When the target required power and the available drive power meet the preset conditions, and the current working state is that the hybrid vehicle is working in the series drive mode, a second control strategy is generated. The second control strategy is used to prevent the hybrid vehicle from switching from the series drive mode to the parallel drive mode. Before obtaining the target power demand of the hybrid vehicle and the available drive power of the hybrid vehicle during the clutch engagement phase, the process includes: The adjustment time required for the engine speed to be adjusted from the series speed to the parallel speed, and the current power demand of the hybrid vehicle are obtained. The target power demand is determined based on the adjustment time and the current power demand. When the engine speed is at the parallel speed, the generator power output and the available discharge power of the power battery during the adjustment time are obtained. Based on the power generation and the available discharge power, determine the available energy power of the drive motor before the clutch engagement ends; After obtaining the adjustment time, the efficiency of the drive motor under the target power requirement; The available drive power is determined based on the available energy power and the efficiency.

7. A vehicle characterized by comprising: The vehicle has a series drive mode and a parallel drive mode, and the vehicle is controlled by the control method for switching between series and parallel drive modes of a hybrid electric vehicle as described in any one of claims 1-5.

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