Method and device for controlling engine speed of hybrid electric vehicle at low temperature

Abstract

The present invention provides a method and device for controlling the engine speed of a hybrid electric vehicle at low temperatures. The method comprises detecting the ambient temperature and the vehicle's driving mode, and determining whether the vehicle's engine speed regulation mode is the self-regulation mode based on the ambient temperature and the driving mode. If so, obtaining a first target torque value for the engine, a second target torque value for the generator, and a third target torque value for the drive motor; and generating a target control strategy based on the first, second, and third target torque values. The target control strategy includes controlling the engine to output the first target torque value and filtering and limiting the second and third target torque values. The present invention solves the problem of the engine speed being unable to be adjusted to the target speed in series mode at extremely low temperatures.

Description

Technical Field

[0001] The present invention relates to the field of vehicle control technology, and in particular to a method and a device for controlling the engine speed of a hybrid electric vehicle at low temperatures. Background Art

[0002] The engine in a dual-motor hybrid system typically operates within its optimal fuel consumption range. When engine load demands change, the generator speed is typically controlled to pull the engine to the target operating range. However, in extremely cold conditions, battery power is severely limited, resulting in insufficient generator power to pull the engine, which in turn prevents the engine from reaching the target speed. However, when a hybrid vehicle is operating in series mode and is exposed to extremely cold temperatures, there is no solution for adjusting the engine speed to the target speed. Summary of the Invention

[0003] The main purpose of the present invention is to provide a method and a control device for controlling the engine speed of a hybrid vehicle at low temperatures, so as to solve the problem that the engine speed cannot be adjusted to the target speed in the series mode at extremely low temperatures.

[0004] To achieve the above-mentioned purpose, according to one aspect of the present invention, a method for controlling the engine speed of a hybrid vehicle at low temperatures is provided, comprising detecting the external ambient temperature and the vehicle's driving mode, wherein the driving mode includes a pure electric mode, a series mode, and a parallel mode; judging, based on the external ambient temperature and the driving mode, whether the vehicle's engine speed regulation mode is the engine's self-regulating speed mode; if so, obtaining a first target torque value of the engine, a second target torque value of the generator, and a third target torque value of the drive motor; generating a target control strategy based on the first target torque value, the second target torque value, and the third target torque value, the target control strategy comprising controlling the engine to output the first target torque value, and filtering and limiting the second target torque value of the generator and the third target torque value of the drive motor.

[0005] Optionally, based on the external ambient temperature and driving mode, determine whether the vehicle's engine speed regulation mode is the engine self-regulating speed mode, including determining whether the external ambient temperature is less than T, where T≤-30°C; if so, determine whether the driving mode is the series mode; if so, determine that the engine speed regulation mode is the engine self-regulating speed mode.

[0006] Optionally, the first target torque value of the engine, the second target torque value of the generator, and the third target torque value of the drive motor are obtained, including calculating the first target torque value, the second target torque value, and the third target torque value after filtering and limiting the driver's required torque when the engine speed regulation mode is the engine's own speed regulation mode.

[0007] Optionally, the first target torque value and the second target torque value are calculated, including obtaining the input torque of the generator after filtering and limiting the required torque when the engine speed regulation mode is the engine self-regulation speed mode; and calculating the first target torque value and the second target torque value based on the input torque.

[0008] Optionally, based on the input torque, a first target torque value and a second target torque value are calculated, including obtaining a first proportional integral coefficient of a first preset mathematical model for calculating the first target torque value, and obtaining a second proportional integral coefficient of a second preset mathematical model for calculating the second target torque value; obtaining a target speed and an actual speed of the engine; determining the first target torque value based on the input torque, the first proportional integral coefficient, the target speed and the actual speed; and determining the second target torque value based on the input torque, the second proportional integral coefficient, the target speed and the actual speed.

[0009] Optionally, based on the input torque, the second proportional-integral coefficient, the target speed and the actual speed, a second target torque value is determined, including subtracting the target speed from the actual speed to obtain a first difference; comparing the product of the second proportional coefficient and the first difference with a preset value to obtain a comparison result; judging whether the comparison result meets a preset condition; and if the comparison result meets the preset condition, determining the second target torque value based on the input torque and the product.

[0010] Optionally, the second target torque value is determined based on the input torque, the second proportional integral coefficient, the target speed and the actual speed, including determining the second target torque value based on the input torque and the preset value when the comparison result does not meet the preset condition.

[0011] According to another aspect of an embodiment of the present invention, a device for controlling the engine operating point speed at low temperatures is provided, comprising: a detection unit for detecting the external ambient temperature and the driving mode of the vehicle, the driving modes including pure electric mode, series mode, and parallel mode; a judgment unit for judging, based on the external ambient temperature and the driving mode, whether the speed regulation mode of the vehicle's engine is the engine's self-regulating speed mode; an acquisition unit for acquiring, if so, the first target torque value of the engine, the second target torque value of the generator, and the third target torque value of the drive motor; a control unit for generating a target control strategy based on the first target torque value, the second target torque value, and the third target torque value, the target control strategy being used to control the engine to output the first target torque value, and to filter and limit the second target torque value and the third target torque value.

[0012] According to another aspect of an embodiment of the present invention, a computer-readable storage medium is provided, which includes a stored program, wherein the computer program is configured to control the execution of the above-mentioned method for controlling the engine speed of a hybrid vehicle at low temperatures when running.

[0013] According to another aspect of an embodiment of the present invention, a processor is provided, which is configured to run a program. The processor executes the above-mentioned method for controlling the engine speed of a hybrid vehicle at low temperatures through the computer program.

[0014] The technical solution of the present invention detects the ambient temperature and the vehicle's driving mode, and determines whether the vehicle's engine speed regulation mode is the self-regulation mode based on the ambient temperature and the driving mode. If so, a first target torque value for the engine, a second target torque value for the generator, and a third target torque value for the drive motor are obtained. Based on the first, second, and third target torque values, a target control strategy is generated. The target control strategy includes controlling the engine to output the first target torque value and filtering and limiting the second and third target torque values. Thus, if the generator is unable to adjust the engine speed to the target speed, the engine speed can be adjusted to the target speed by controlling the engine to output the first target torque value. Furthermore, by filtering and limiting the second and third target torque values, the power consumption and power generation of the drive motor and the generator at the same time can be balanced. The method for controlling the engine speed at low temperatures in a hybrid vehicle of the present invention achieves the technical effect of adjusting the engine speed to the target speed in extremely low temperature environments while ensuring that the engine load matches the actual engine output. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0016] Figure 1 It shows a structural block diagram of an embodiment of a dual-motor series-parallel hybrid system according to the present invention;

[0017] Figure 2 A schematic flow chart showing a first embodiment of a method for controlling the engine speed of a hybrid vehicle at low temperatures according to the present invention;

[0018] Figure 3 A schematic flow chart showing a second embodiment of a method for controlling the engine speed of a hybrid vehicle at low temperatures according to the present invention;

[0019] Figure 4 A schematic flow chart showing a third embodiment of a method for controlling the engine speed of a hybrid vehicle at low temperatures according to the present invention;

[0020] Figure 5 A schematic flow chart showing a fourth embodiment of a method for controlling the engine speed of a hybrid vehicle at low temperatures according to the present invention is shown;

[0021] Figure 6 A structural block diagram of an embodiment of a control device according to the present invention is shown;

[0022] Figure 7 A structural block diagram of an embodiment of an electronic device for a vehicle according to the present invention is shown. DETAILED DESCRIPTION

[0023] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0024] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0025] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way are interchangeable where appropriate, so that the embodiments of the present application described herein can, for example, be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0026] Now, exemplary embodiments according to the present application will be described in more detail with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in a variety of different forms and should not be interpreted as being limited to the embodiments described herein. It should be understood that these embodiments are provided to make the disclosure of this application thorough and complete, and to fully convey the concepts of these exemplary embodiments to those of ordinary skill in the art. In the accompanying drawings, for the sake of clarity, the thickness of layers and regions may be exaggerated, and the same reference numerals are used to represent the same devices, and thus their descriptions will be omitted.

[0027] According to an embodiment of the present invention, a method embodiment of a method for controlling the engine speed of a hybrid vehicle at low temperatures is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0028] like Figure 1The figure shows the block diagram of a dual-motor series-parallel hybrid system. The dual-motor series-parallel hybrid system includes wheels 1, an HCU controller 2, a battery management system 3, batteries 4, a first MCU controller 5, a first inverter 6, a drive motor 7, a second inverter 8, a generator 9, a second MCU controller 10, an engine 11, an engine management system 12, a clutch 13, a 12V system 14, a high-voltage system 15, and a CAN communication system 16. In this dual-motor series-parallel hybrid system, the drive motor is directly coupled to the reduction mechanism via gears. The generator is connected to the engine via meshing gears, and the engine flywheel connects and disconnects power to the rear-end reduction mechanism via a clutch. The dual-motor hybrid system has three main operating modes: pure electric mode, series mode, and parallel mode. In pure electric mode, the engine is stopped, the clutch is engaged, and the drive motor drives alone. In series mode, the engine runs, driving the generator, the clutch is engaged, and the drive motor drives alone. In parallel mode, the engine drives, the clutch is engaged, the generator generates power or follows, and the drive motor assists or follows. In the series mode at extremely low temperatures, the battery power is severely limited and the generator is unable to adjust the engine speed to the target speed. At this time, the HCU controls the EMS to adjust the engine itself to the target operating area.

[0029] like Figure 2 FIG. 1 is a flow chart of a first embodiment of a method for controlling the engine speed of a hybrid vehicle at low temperature according to the present application. Figure 2 As shown, the method for controlling the engine speed of a hybrid vehicle at low temperature includes the following steps:

[0030] Step S102, detecting the external ambient temperature and the vehicle's driving mode, wherein the driving mode includes a pure electric mode, a series mode, and a parallel mode;

[0031] Step S104, judging whether the speed regulation mode of the vehicle's engine is the engine self-regulation speed regulation mode according to the external ambient temperature and the driving mode;

[0032] Step S106, if yes, obtain the first target torque value of the engine, the second target torque value of the generator, and the third target torque value of the drive motor;

[0033] Step S108 : generating a target control strategy based on the first target torque value, the second target torque value, and the third target torque value. The target control strategy includes controlling the engine to output the first target torque value and filtering and limiting the second target torque value and the third target torque value.

[0034] Through the above steps, even if the generator is unable to adjust the engine speed to the target speed, the engine can be controlled to output the first target torque value to achieve the purpose of adjusting the engine speed to the target speed. Furthermore, by filtering and limiting the second and third target torque values, the power consumption and power generation of the drive motor and generator at the same time can be balanced. The hybrid vehicle low-temperature engine speed control method of the present application not only achieves the technical effect of adjusting the engine speed to the target speed in extremely low temperature environments, but also ensures that the engine load matches the actual engine output.

[0035] Alternatively, as Figure 3 The figure shows a flow chart of a second embodiment of the method for controlling the engine speed of a hybrid vehicle at low temperatures according to the present application. According to the ambient temperature and the driving mode, it is determined whether the speed regulation mode of the vehicle's engine is the engine self-regulating speed mode, including determining whether the ambient temperature is less than T, where T≤-30°C. Specifically, when the ambient temperature is less than -30°C, it is determined whether the driving mode is the series mode. If so, it is determined that the engine speed regulation mode is the engine self-regulating speed mode (corresponding to Figure 3 In this embodiment, when the ambient temperature is less than -30°C and the driving mode is series mode, the battery power is severely limited, and the generator is unable to adjust the engine speed to the target speed. At this time, the HCU controls the EMS, and the HCU issues a low-battery-power flag, exiting the original generator-regulated engine speed mode and entering the engine-regulated speed mode. The engine then relies on its own speed regulation to achieve the purpose of adjusting the engine speed to the target speed. Furthermore, in series mode, even if the battery has no charge or discharge capacity due to ultra-low temperature conditions, the vehicle can still be driven.

[0036] Optionally, the first target torque value of the engine, the second target torque value of the generator, and the third target torque value of the drive motor are obtained, including calculating the first target torque value, the second torque value, and the third target torque value after filtering and limiting the driver's required torque when the engine speed regulation mode is the engine's own speed regulation mode.

[0037] Optionally, calculating the first and second target torque values ​​includes, when the engine speed regulation mode is the self-regulation mode, filtering and limiting the demanded torque, obtaining the generator input torque, and calculating the first and second target torque values ​​based on the input torque. In this embodiment, due to the slow engine response speed at low temperatures, a certain degree of battery over-discharge may occur under conditions where the engine torque increases rapidly. By filtering and limiting the demanded torque, the rate of increase of the limited demanded torque matches the actual torque response rate of the engine, thereby avoiding the problem of battery over-discharge.

[0038] like Figure 4 The figure is a flow chart of the third embodiment of the method for controlling the engine speed of a hybrid vehicle at low temperature according to the present application. First, the ambient temperature and the driving mode of the vehicle are detected. According to the ambient temperature and the driving mode, it is determined whether the speed adjustment mode of the vehicle's engine is the engine self-regulation speed mode (corresponding to the Figure 4 In the engine self-regulating speed mode, the rising slope of the driver's required torque is limited. After limiting the rising slope of the driver's required torque, the third target torque value of the drive motor is calculated.

[0039] Alternatively, as Figure 5 The flowchart of the fourth embodiment of the method for controlling engine speed at low temperatures for a hybrid vehicle according to the present application is shown. Based on the input torque, a first target torque value and a second target torque value are calculated. This includes obtaining a first proportional-integral coefficient of a first preset mathematical model used to calculate the first target torque value, obtaining a second proportional-integral coefficient of a second preset mathematical model used to calculate the second target torque value, and obtaining a target speed and an actual speed of the engine. The first target torque value is determined based on the input torque, the first proportional-integral coefficient, the target speed, and the actual speed. The second target torque value is determined based on the input torque, the second proportional-integral coefficient, the target speed, and the actual speed.

[0040] Specifically, Figure 5 The generator target torque T2 is the second target torque value. Figure 5 The target engine torque in is the first target torque value. The first preset mathematical model is as follows:

[0041] Engine target torque = generator torque × speed ratio + PI (engine target speed - engine actual speed), where PI is the first proportional integral coefficient.

[0042] The second preset mathematical model is as follows:

[0043] Generator target torque T2 = generator torque + P (engine target speed - engine actual speed), where P is the second proportional integral coefficient.

[0044] In this embodiment, the generator torque in the first preset mathematical model and the second preset model is the input torque. Since the torque response speed of the engine is slow at low temperatures, the actual torque of the engine will be less than the target torque sent by the HCU when the speed increases, resulting in the load on the engine end being greater than its output power, which will cause the engine speed to drop. If the engine response speed is too slow, it will cause the engine to stall. To solve this problem, by detecting the external ambient temperature and the vehicle's driving mode, it is determined whether the vehicle's engine speed regulation mode is the engine self-regulation speed mode (corresponding to the external ambient temperature and the driving mode). Figure 5 When the engine speed regulation mode is the engine self-regulation speed mode, the generator switches to the torque mode, and the HCU calculates the target torque of the engine based on the target engine speed calculated by the torque distribution module. Specifically, the input torque of the generator (i.e. Figure 5 Based on the input torque (generator torque T1), the first target torque value of the engine and the second target torque value of the generator are calculated. The algorithm for adjusting the second target torque value of the generator in the vehicle control unit (HCU) adds a proportional torque offset (P(target engine speed - actual engine speed)) to the generator input torque calculated by the torque distribution module when low-temperature conditions are triggered. This offset aligns the engine load with the actual engine output, preventing the actual engine torque from being less than the target torque due to the slower engine response speed and faster generator torque response at low temperatures. This, in turn, results in the generator power being greater than the engine output power, leading to a reduction in engine speed.

[0045] Optionally, a second target torque value is determined based on the input torque, a second proportional-integral coefficient, a target speed, and an actual speed, including subtracting the target speed from the actual speed to obtain a first difference. The product of the second proportional-integral coefficient and the first difference is compared with a preset value to obtain a comparison result. A determination is made as to whether the comparison result satisfies a preset condition. If the comparison result satisfies the preset condition, a second target torque value is determined based on the input torque and the product. In this embodiment, the preset value is 0. If the product of the second proportional-integral coefficient and the first difference is greater than 0, the product is added to the value of the generator input torque calculated by the torque distribution module to obtain the second target torque value of the generator, further ensuring that the engine load matches the actual engine output.

[0046] Optionally, a second target torque value is determined based on the input torque, the second proportional-integral coefficient, the target speed, and the actual speed, including determining the second target torque value based on the input torque and the preset value if the comparison result does not satisfy a preset condition. In this embodiment, if the product of the second proportional-integral coefficient and the first difference is less than 0, the product is assigned a value of 0, thereby further ensuring that the engine load matches the actual engine output.

[0047] According to another specific embodiment of the present application, a control device for the engine operating point speed at low temperature is provided, such as Figure 6 The figure shows a block diagram of the structure of the control device of the present application, which includes a detection unit 42, a judgment unit 44, an acquisition unit 46 and a control unit 48. The detection unit 42 is used to detect the external ambient temperature and the driving mode of the vehicle, and the driving mode includes a pure electric mode, a series mode, and a parallel mode. The judgment unit 44 is used to determine whether the speed regulation mode of the vehicle's engine is the engine self-regulating speed mode based on the external ambient temperature and the driving mode. The acquisition unit 46 is used to obtain the first target torque value of the engine, the second target torque value of the generator, and the third target torque value of the drive motor when the engine speed regulation mode is the engine self-regulating speed mode. The control unit 48 generates a target control strategy based on the first target torque value, the second target torque value, and the third target torque value. The target control strategy is used to control the engine to output the first target torque value and filter and limit the second target torque value and the third target torque value.

[0048] In this embodiment, the ambient temperature and the vehicle's driving mode are detected, and based on the ambient temperature and driving mode, a determination is made as to whether the vehicle's engine speed regulation mode is the self-regulation mode. If so, a first target torque value for the engine, a second target torque value for the generator, and a third target torque value for the drive motor are obtained. Based on the first, second, and third target torque values, a target control strategy is generated. The target control strategy includes controlling the engine to output the first target torque value and filtering and limiting the second and third target torque values. Thus, if the generator is unable to adjust the engine speed to the target speed, the engine speed can be adjusted to the target speed by controlling the engine to output the first target torque value. Furthermore, by filtering and limiting the second and third target torque values, the power consumption and power generation of the drive motor and generator at the same time are balanced. The hybrid vehicle low-temperature engine speed control method of this application achieves the technical effect of adjusting the engine speed to the target speed in extremely low-temperature conditions while ensuring that the engine load matches the actual engine output.

[0049] According to another specific embodiment of the present application, a computer-readable storage medium is also provided, which includes a stored program, wherein when the program is running, the device where the computer-readable storage medium is located is controlled to execute the steps of the method for controlling the engine speed of a hybrid vehicle at low temperatures in the above embodiment.

[0050] According to another specific embodiment of the present application, a processor is further provided, which is used to run a program, wherein when the program is run, the steps of the method for controlling the engine speed of a hybrid vehicle at low temperatures in the above embodiment are executed.

[0051] The method for controlling the engine speed of a hybrid vehicle at low temperatures in the above embodiment can be executed in an electronic device or similar computing device in a vehicle that includes a memory and a processor. That is, according to another specific embodiment of the present application, an electronic device for a vehicle is also provided. Figure 7 The figure shows a block diagram of the structure of the electronic device of the vehicle. Taking the electronic device running on the vehicle as an example, the electronic device of the vehicle may include one or more processors 102 (the processor may include but is not limited to a central processing unit (CPU), a graphics processing unit (GPU), a digital signal processing (DSP) chip, a microprocessor (MCU), a programmable logic device (FPGA), a neural network processor (NPU), a tensor processor (TPU), an artificial intelligence (AI) type processor, etc.) and a memory 104 for storing data. Optionally, the electronic device of the vehicle may also include a transmission device 106 for communication functions, an input and output device 108, and a display 110. It can be understood by those skilled in the art that Figure 7 The structure shown is for illustration only and does not limit the structure of the electronic device of the vehicle. For example, the electronic device of the vehicle may include more or fewer components than those described above, or have a configuration different from that described above.

[0052] The memory 104 can be used to store computer programs, for example, software programs and modules of application software, such as the computer program corresponding to the information processing method in the embodiment of the present invention. The processor 102 executes various functional applications and data processing by running the computer program stored in the memory 104, that is, implements the above-mentioned information processing method. The memory 104 may include a high-speed random access memory and may also include a non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memory. In some examples, the memory 104 may further include a memory remotely located relative to the processor 102, and these remote memories may be connected to the mobile terminal via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0053] The transmission device 106 is used to receive or transmit data via a network. A specific example of the aforementioned network may include a wireless network provided by the mobile terminal's communications provider. In one embodiment, the transmission device 106 includes a network interface controller (NIC), which can be connected to other network devices via a base station to enable communication with the Internet. In one embodiment, the transmission device may be a radio frequency (RF) module, which is used to communicate with the Internet wirelessly.

[0054] The display 110 may be, for example, a touch-screen liquid crystal display (LCD) and a touch display (also referred to as a "touch screen" or "touch display screen"). The LCD may enable a user to interact with a user interface of the mobile terminal. In some embodiments, the mobile terminal may have a graphical user interface (GUI), and a user may interact with the GUI by finger contact and / or gestures on a touch-sensitive surface. The human-computer interaction functions herein may optionally include the following interactions: creating web pages, drawing, word processing, creating electronic documents, games, video conferencing, instant messaging, sending and receiving emails, call interfaces, playing digital videos, playing digital music, and / or web browsing, etc. Executable instructions for executing the above-mentioned human-computer interaction functions are configured / stored in a computer program product or readable storage medium executable by one or more processors.

[0055] The present invention utilizes the method for controlling engine speed in a hybrid vehicle at low temperatures. In series mode, when the battery is unable to charge or discharge due to ultra-low temperature conditions, the torque of the generator and engine can be distributed without the battery participating in the operation. The engine itself regulates the engine speed to achieve the target speed, thereby enabling vehicle travel even in the extremely low-temperature series mode. Furthermore, the system torque increase rate is limited based on the actual engine torque increase rate, thereby preventing battery over-discharge. Furthermore, in calculating the second target torque value of the generator, a proportionally controlled torque offset is added to the generator input torque calculated by the torque distribution module. This offset is "P(target engine speed - actual engine speed)". If the offset is less than 0, the offset is set to 0, thereby ensuring that the offset is greater than or equal to 0. This ensures that the actual power generated by the generator torque is always less than or equal to the engine power, thereby avoiding the occurrence of under-suppression of the engine speed and resolving the problem of the engine speed being unable to adjust to the target speed in the extremely low-temperature series mode.

[0056] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used herein to describe the spatial positional relationship of a device or feature to other devices or features as shown in the figures. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figures. For example, if the device in the drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0057] In addition to the above, it should be noted that references to "one embodiment," "another embodiment," "an embodiment," and the like in this specification refer to specific features, structures, or characteristics described in conjunction with that embodiment as included in at least one embodiment generally described in this application. The appearance of the same expression in multiple places in the specification does not necessarily refer to the same embodiment. Furthermore, when a specific feature, structure, or characteristic is described in conjunction with any embodiment, it is intended that such feature, structure, or characteristic, when implemented in conjunction with other embodiments, also falls within the scope of the present invention.

[0058] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0059] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A method for controlling the engine speed of a hybrid vehicle at low temperatures, characterized in that: include: Detecting the ambient temperature and the vehicle's driving mode, wherein the driving mode includes a pure electric mode, a series mode, and a parallel mode; determining, based on the ambient temperature and the driving mode, whether the speed regulation mode of the engine of the vehicle is the engine self-regulation speed mode; If yes, obtaining a first target torque value of the engine, a second target torque value of the generator, and a third target torque value of the drive motor; Based on the first target torque value, the second target torque value, and the third target torque value, a target control strategy is generated. The target control strategy includes controlling the engine to output the first target torque value and filtering and limiting the second target torque value and the third target torque value, so as to ensure that the power consumption and power generation of the drive motor and the generator are balanced at the same time.

2. The method for controlling the engine speed of a hybrid vehicle at low temperature according to claim 1, characterized in that: Determining, based on the ambient temperature and the driving mode, whether the speed regulation mode of the engine of the vehicle is the engine self-regulating speed mode includes: Determine whether the external environment temperature is less than T, where T≤-30°C; If yes, determining whether the driving mode is the series mode; If yes, it is determined that the speed regulation mode of the engine is the engine self-regulation speed mode.

3. The method for controlling the engine speed of a hybrid vehicle at low temperature according to claim 2, characterized in that: Obtaining a first target torque value of the engine, a second target torque value of the generator, and a third target torque value of the drive motor includes: When the engine speed regulation mode is the engine self-regulation speed mode, the first target torque value, the second target torque value, and the third target torque value are calculated after filtering and limiting the driver's required torque.

4. The method for controlling the engine speed of a hybrid vehicle at low temperature according to claim 3, characterized in that: Calculating the first target torque value and the second target torque value includes: When the engine speed regulation mode is the engine self-regulation speed mode, the required torque is filtered and limited, and then the input torque of the generator is obtained; The first target torque value and the second target torque value are calculated based on the input torque.

5. The method for controlling the engine speed of a hybrid vehicle at low temperature according to claim 4, characterized in that: Calculating the first target torque value and the second target torque value based on the input torque includes: Obtaining a first proportional-integral coefficient of a first preset mathematical model for calculating the first target torque value, and obtaining a second proportional-integral coefficient of a second preset mathematical model for calculating the second target torque value; Obtaining a target speed and an actual speed of the engine; determining the first target torque value based on the input torque, the first proportional-integral coefficient, the target speed, and the actual speed; determining the second target torque value based on the input torque, the second proportional-integral coefficient, the target speed, and the actual speed; in: The first preset mathematical model is as follows: Engine target torque = generator torque × speed ratio + PI (engine target speed - engine actual speed), where PI is the first proportional integral coefficient; The second preset mathematical model is as follows: Generator target torque T2 = generator torque + P (engine target speed - engine actual speed), where P is the second proportional integral coefficient.

6. The method for controlling the engine speed of a hybrid vehicle at low temperatures according to claim 5, characterized in that: Determining the second target torque value based on the input torque, the second proportional-integral coefficient, the target speed, and the actual speed includes: Subtracting the target speed from the actual speed to obtain a first difference; Comparing the product of the second proportional integral coefficient and the first difference with a preset value to obtain a comparison result; Determining whether the comparison result meets a preset condition; When the comparison result satisfies a preset condition, the second target torque value is determined based on the input torque and the product.

7. The method for controlling the engine speed of a hybrid vehicle at low temperatures according to claim 6, characterized in that: Determining the second target torque value based on the input torque, the second proportional-integral coefficient, the target speed, and the actual speed includes: When the comparison result does not satisfy a preset condition, the second target torque value is determined based on the input torque and the preset value.

8. A control device for engine operating point speed at low temperature, characterized in that: include: a detection unit, detecting the external ambient temperature and the vehicle's driving mode, wherein the driving mode includes a pure electric mode, a series mode, and a parallel mode; a determination unit, configured to determine, based on the ambient temperature and the driving mode, whether the speed regulation mode of the engine of the vehicle is the engine self-regulation speed mode; an acquiring unit, if yes, acquiring a first target torque value of the engine, a second target torque value of the generator, and a third target torque value of the drive motor; A control unit generates a target control strategy based on the first target torque value, the second target torque value, and the third target torque value. The target control strategy is used to control the engine to output the first target torque value and filter and limit the second target torque value and the third target torque value, so as to ensure that the power consumption and power generation of the drive motor and the generator are balanced at the same time.

9. A computer-readable storage medium, characterized in that: The computer-readable storage medium includes a stored program, wherein the program, when executed, executes the method for controlling the engine speed of a hybrid vehicle at low temperature according to any one of claims 1 to 7.

10. A processor, characterized in that: The processor is configured to run a program, wherein the program, when running, executes the method for controlling the engine speed of a hybrid vehicle at low temperature according to any one of claims 1 to 7.

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