Hybrid vehicle, engine start control method, medium, and controller

Abstract

A hybrid vehicle, its engine starting control method, medium, and controller, related to the technical field of hybrid vehicles, includes: after satisfying an engine starting condition, obtaining an engine oil temperature and a coolant temperature of the engine, looking up in a predetermined corresponding relationship according to the engine oil temperature and the coolant temperature to obtain a work loss torque of the engine, and controlling an ISG motor of the hybrid vehicle according to the work loss torque to start the engine.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This disclosure claims priority to and benefit of Chinese Patent Application No. 202211504126.3, entitled "Hybrid Electric Vehicle and Control Method, Medium, and Controller for Starting the Engine Thereof," filed on November 28, 2022. The entire contents of the above application are incorporated herein by reference.

[0002] Field The present disclosure relates to the field of hybrid electric vehicle technology, and more particularly to a hybrid electric vehicle and a control method, medium, and controller for engine starting thereof.

[0003] Background technology In a hybrid electric vehicle, when the engine is involved in power generation, it undergoes operating states such as engine start, power generation, and stop. The engine and the integrated starter-generator-motor (ISG motor) must cooperate in these operating states. The cooperation process involves torque control. In addition, in actual operating states, the engine has torque loss. In related technologies, the engine loss torque used may be significantly different from the actual loss torque, causing inaccuracies in engine start control and affecting the smoothness of the ISG motor operation.

[0004] Summary of the Invention An object of the present disclosure is to provide a hybrid electric vehicle and a control method, medium, and controller for starting its engine, in order to improve the accuracy of engine starting control and ensure smooth operation of the ISG motor.

[0005] According to a first aspect, the present disclosure provides a control method for starting an engine of a hybrid electric vehicle, the method including: obtaining an engine oil temperature and an engine coolant temperature after an engine start condition is satisfied; searching a predetermined correspondence relationship according to the engine oil temperature and the coolant temperature to obtain a work loss torque of the engine; and controlling an ISG motor of the hybrid electric vehicle according to the work loss torque to start the engine.

[0006] According to a second aspect, the present disclosure provides a computer-readable storage medium storing a computer program that, when executed by a processor, performs the aforementioned control method for engine starting of a hybrid electric vehicle.

[0007] According to a third aspect, the present disclosure provides a controller including a memory, a processor, and a computer program stored in the memory, the computer program, when executed by the processor, implementing the aforementioned control method for engine starting of a hybrid electric vehicle.

[0008] According to a fourth aspect, the present disclosure provides a hybrid electric vehicle including an engine, an ISG motor, and the aforementioned controller.

[0009] According to the hybrid electric vehicle and its control method, medium, and controller for engine starting in the embodiments of the present disclosure, during engine starting and control, the engine loss torque is obtained by searching a table according to the engine coolant temperature and the engine oil temperature, and to perform engine starting control, the work torque (i.e., the target torque) of the ISG motor is back-calculated by using a torque balance equation, resulting in a more accurate engine loss torque used in the engine starting control process, more accurate torque control of the ISG motor, better cooperative function between the ISG motor and the engine, and improved performance of engine speed variability.

[0010] Additional aspects and advantages of the disclosure will be set forth in the description that follows, and in part will be obvious from the description, or may be learned by practice of the disclosure. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic diagram of a power framework for a hybrid electric vehicle according to one embodiment of the present disclosure. [Figure 2] 1 is a schematic diagram of the performance of an engine start control of a hybrid electric vehicle in the related art; [Figure 3] 3 is a flowchart of a control method for engine starting of a hybrid electric vehicle according to one embodiment of the present disclosure. [Figure 4] 4 is a flowchart of a control method for engine starting of a hybrid electric vehicle according to another embodiment of the present disclosure. [Figure 5] 1 is a flowchart illustrating a calculation of combustion torque according to one embodiment of the present disclosure. [Figure 6] 10 is a flowchart illustrating a calculation of rotational torque according to an embodiment of the present disclosure. [Figure 7] 10 is a flowchart illustrating a correction of torque loss according to an embodiment of the present disclosure. [Figure 8] 2 is a schematic diagram of the performance of a hybrid electric vehicle engine start control according to the present disclosure; [Figure 9] FIG. 2 is a structural block diagram of a controller according to one embodiment of the present disclosure. [Figure 10] 1 is an architectural block diagram of a hybrid electric vehicle according to one embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0012]

[0023] The embodiments of the present disclosure are described in detail below. Examples of the embodiments are shown in the accompanying drawings, and the same or similar reference numerals in all the accompanying drawings indicate the same or similar components or components having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to only illustrate the present disclosure and cannot be construed as limiting the present disclosure.

[0013] In this disclosure, the power architecture of a hybrid electric vehicle is shown in FIG. 1 and includes an integrated starter-generator-motor (ISG motor), an engine (ENG), a clutch (C), a power battery (Battery), and drive motors (M1 and M2). The connection to the power battery is a high-voltage cable connection, the other connections are mechanical connections, and W are the wheels of the hybrid electric vehicle. When the engine is started and needs to run, the ISG motor drags the engine to rotate. In this case, the ISG motor is the power source, and the engine is the load. When the engine needs to supplement the power battery with electrical energy, the running engine drives and rotates the ISG motor, and the ISG motor generates electrical energy to supplement the power battery. In this case, the engine is the power source, and the ISG motor is the load. When the engine needs to be directly involved in driving, the clutch is engaged, and the engine transmits power directly to the wheel ends.

[0014] In the related art, the same loss torque is used when the ISG motor drives the engine to start, regardless of the ambient temperature. The engine loss torque is inaccurate. Furthermore, the ISG motor loads and unloads torque at a fixed gradient. There is instability in the rotation speed transition during startup, which causes jitter, rushing, and poor starting performance. From an analysis of the marked points in Figure 2, it can be seen that the starting process of the related art has at least the following six problems:

[0015] 1. The drag torque of the ISG motor is excessively large, the synchronization time between the engine and ISG motor rotation speeds is relatively long, the workload on the torsional shock absorber is large, and this may cause problems such as abnormal noise during startup.

[0016] 2. The engine loss torque is inaccurate, and the engine torque control precision is not high.

[0017] 3. The rotation speed of the engine has drop pits, and the fluctuation of rotation speed causes jitter.

[0018] 4. Engine upstroke speed is excessively high, usually about 300 rpm greater than idle speed.

[0019] 5. The unloading torque gradient of the ISG motor is fixed, which is usually a fixed value and cannot adapt to different ambient temperatures.

[0020] 6. The torque of the ISG motor is not completely unloaded, and the force on the transmission shaft is unbalanced, causing a secondary upstroke in the rotation speed.

[0021] In consideration of this, the present disclosure provides a hybrid electric vehicle and a control method, medium, and controller for starting its engine. To improve the accuracy of engine start control and ensure smooth operation of the ISG motor, different loss torques are used to control the ISG motor to drag and start the engine at different ambient temperatures. Hereinafter, a hybrid electric vehicle and a control method, medium, and controller for starting its engine according to embodiments of the present disclosure will be described with reference to the accompanying drawings.

[0022] 3 is a flowchart of a control method for engine starting of a hybrid electric vehicle according to one embodiment of the present disclosure. As shown in FIG. 3, the control method for engine starting includes:

[0023] S31: After the engine start conditions are met, the engine oil temperature and the engine coolant temperature are obtained.

[0024] The engine start condition may be that the hybrid electric vehicle enters a hybrid electric vehicle (HEV) mode, or that the hybrid electric vehicle needs to be charged.

[0025] In some examples, the hybrid electric vehicle is provided with an HEV switch button, and when a user presses the button, the overall vehicle controller of the hybrid electric vehicle obtains a mode switch command for the hybrid electric vehicle, and it may be determined that the hybrid electric vehicle currently meets the engine start condition.

[0026] In some other examples, it is determined that the engine start condition is currently met if the current remaining power amount of the power battery in the hybrid electric vehicle is less than a first power amount threshold, which may be preset, for example, to 10%.

[0027] In still some other examples, when the hybrid electric vehicle is in a stopped state, it is determined that the engine start condition is currently satisfied when it is detected that the accelerator pedal depth of the hybrid electric vehicle is greater than an accelerator pedal depression threshold and the remaining energy of the power battery is less than a second energy threshold and greater than a first energy threshold.

[0028] S32: A preset correspondence relationship is searched according to the engine oil temperature and the coolant temperature to obtain the engine work loss torque.

[0029] Specifically, after the engine start condition is met, the ISG motor and the engine need to work together to start the engine. To ensure accuracy of the engine loss torque (including pump loss, ventilation loss, attachment friction loss, etc.) during engine start control, the present disclosure considers that the engine loss torque varies due to different viscosities of engine oil and engine friction at different engine oil and coolant temperatures. A correspondence relationship between the engine oil temperature, the coolant temperature, and the engine loss torque (i.e., the aforementioned preset correspondence relationship, which may be stored in table form) has been established. Therefore, when the engine start condition is met, the engine oil temperature and the engine coolant temperature are first obtained. Furthermore, the preset correspondence relationship is searched to obtain the corresponding loss torque (i.e., the aforementioned work loss torque of the engine). The engine oil temperature and the coolant temperature may be detected by setting corresponding temperature sensors.

[0030] S33: The ISG motor of the hybrid electric vehicle is controlled according to the work loss torque to start the engine.

[0031] Specifically, after the work loss torque of the engine is obtained, a target torque of the ISG motor is obtained based on the work loss torque (e.g., a correspondence relationship between the loss torque and the target torque may be established, and then the target torque of the ISG motor may be obtained by searching for the correspondence relationship based on the work loss torque), and load control and unloading control may be performed on the ISG motor according to the target torque. The load control may be to control the ISG motor to load torque to the target torque and drag the engine to rotate at the target torque. The unloading control may be to control the ISG motor to unload torque when the engine rotation speed reaches a rotation speed threshold N1. Note that while the ISG motor is controlled to unload torque, the engine is controlled to be ignited and fuel is injected. When the engine rotation speed reaches a rotation speed threshold N2, an Engine Management System (EMS) determines that the engine has been started. The engine then transitions to control of a Vehicle Control Unit (VCU) target torque and responds to the VCU target torque.

[0032] According to the control method for engine starting of a hybrid electric vehicle in this embodiment of the present disclosure, when the engine starting condition is met, the engine oil temperature and the engine coolant temperature are first obtained, and a preset correspondence relationship is further searched for to obtain the engine work loss torque, and the ISG motor is controlled based on the work loss torque to start the engine, so that the accuracy of the engine starting control can be improved and the smooth operation of the ISG motor can be ensured.

[0033] In some embodiments of the present disclosure, as shown in FIG. 4, the control method for engine starting further includes:

[0034] S41: When the engine is started, the crank angle and crankshaft angular velocity of the engine are obtained.

[0035] Specifically, as shown in FIG. 5, the same sampling frequency as the sampling frequency of the engine rotation speed may be used. During the engine starting process, the crankshaft position gear position at this time point may be obtained by using a crankshaft position sensor, and the engine crank rotation angle α may be obtained according to the crankshaft position gear position. The crankshaft rotation angle α is the crank rotation angle corresponding to the engine cylinder performing expansion work, and ranges from 0° to 180°, and is expressed as the crankshaft rotation angle of the expansion work stroke. In addition, as shown in FIG. 6, the same sampling frequency as the engine rotation speed may be used, and the crankshaft angular velocity may be obtained by using an angular velocity sensor.

[0036] S42: The combustion torque generated on the engine crankshaft by the combustion gas in the engine cylinder is obtained according to the crank angle, and the rotational torque of the transmission shaft is obtained according to the crankshaft angular velocity.

[0037] In some examples, the combustion torque is obtained by using the following equation: T 燃焼 =p i *s*cosβ*r*sin(α+β), In the formula, T 燃焼 is the combustion torque, β=arcsin(r*sinα / l), is the crankshaft connecting rod swing angle, l is the crankshaft connecting rod length, r is the crank radius, s is the surface area of ​​the piston head in the cylinder, α is the crank rotation angle, and p i is the combustion burst pressure in the cylinder.

[0038] Specifically, referring to Figure 5, in the engine of a hybrid electric vehicle, the crankshaft connecting rod length l, crank radius r, and piston head surface area s are fixed values, and the correspondence relationship between the crankshaft connecting rod swing angle β and the crank rotation angle α satisfies β = arcsin(r * sinα / l), that is, the crankshaft connecting rod swing angle β and the crank rotation angle α have a one-to-one correspondence. The crankshaft connecting rod length l, crank radius r, piston head surface area s, connecting rod swing angle β, crank rotation angle α, and the combustion burst pressure p in the cylinder are i If all of the above are known, the combustion torque generated by the high-temperature, high-pressure combustion gases in the cylinder on the crankshaft can be obtained by analyzing the force acting on the crankshaft of the piston, and T 燃焼 =p i *s*cosβ*r*sin(α+β).

[0039] In some examples, the rotational torque is obtained by using the following equation: T トルク =J*a i , In the formula, T トルク is the rotational torque, J is the moment of inertia of the transmission shaft, and a i =(w i -w i-1 ) / t, where w is the crank angular acceleration at the i-th time point. i is the crankshaft angular velocity at the i-th time point, and t is the time difference between the i-th time point and the (i-1)-th time point.

[0040] Specifically, when the engine has a non-constant rotational speed, rotational torque may exist across the engine and transmission shaft due to rotational acceleration. Referring to Figure 6, the moment of inertia of the rotating parts connected to the engine crankshaft, flywheel, torsional shock absorber, and ISG motor can be obtained by integration and accumulation. Note that for a determined combination of the ISG motor and engine, the moment of inertia J is a fixed value and may be stored in advance, and then directly read and used when needed.

[0041] Crankshaft angular velocity w at the current sampling point i and the crankshaft angular velocity w at the previous sampling point i-1 After obtaining the angular acceleration a i is the formula (w i -w i-1 ) / t, and then the rotational torque T of the transmission shaft at time i トルク is the formula J*a i is obtained according to

[0042] S43: The initial torque of the ISG motor is obtained, and the actual loss torque of the engine at the engine oil temperature and coolant temperature is obtained according to the combustion torque, rotation torque and initial torque.

[0043] In some examples, obtaining the actual loss torque of the engine at the engine oil temperature and coolant temperature according to the combustion torque, rotational torque, and initial torque may include calculating the difference between the combustion torque and the rotational torque, calculating the sum of the difference and the initial torque, and using the sum as the actual loss torque.

[0044] Specifically, as shown in Figure 7, as can be seen from the torque analysis performed on the transmission shaft, at any point in time, the force equilibrium T 燃焼 +T ISG =T 損失 +T 回転トルク There exists. T ISG is a positive torque when the engine is started, a negative torque when the engine is engaged in power generation, and when the engine is rotating at a constant speed, T トルク is 0 and T 燃焼 +T ISG =T 損失 When the engine rotates at a non-constant speed, T トルク is not 0, but T 燃焼 +T ISG =T 損失 +T 回転トルク is.

[0045] Referring to Figure 7, T 損失 =T燃焼 +T ISG -T 回転トルク is the formula T 燃焼 +T ISG =T 損失 +T 回転トルク can be obtained by transforming T 燃焼 , T 回転トルク , and T ISG If all are known, the actual torque loss of the engine, T 損失 is the formula T 損失 =T 燃焼 +T ISG -T 回転トルク It can be calculated according to:

[0046] It should be noted that the initial torque of the ISG motor used to calculate the actual loss torque is a constant value, and may be the target torque of the ISG motor used when the engine is started for the first time after the hybrid electric vehicle is delivered, which is a value set by the delivery. In the process of controlling the engine start of a hybrid electric vehicle, the formula T 損失 =T 燃焼 +T ISG -T 回転トルク According to the stable T 損失 To obtain {overscore (R)}, the actual loss torque can be continuously calculated according to the combustion torque and the rotation torque, so as to obtain a stable difference between the combustion torque and the rotation torque.

[0047] S44: The preset correspondence is updated according to the actual torque loss.

[0048] Specifically, in actual engineering applications, engine torque loss is obtained by interpolation on a pre-set table stored in the EMS chip. The torque loss table is typically measured on an engine rig using the lost cylinder method, the fuel consumption line method, or the drag inversion method. Most gas engines are measured using the drag inversion method. With the drag inversion method, engine torque loss is typically measured at engine coolant temperatures above 85°C and engine oil temperatures above 85°C. Therefore, the torque loss measured using the drag inversion method does not take into account the rotational torque of the transmission shaft, nor does it take into account the difference in engine torque loss at different engine coolant and engine oil temperatures. As a result, during actual service conditions, there is a large discrepancy between the engine torque loss and the actual torque loss obtained via table lookup.

[0049] The actual torque loss value of the engine at any time when the entire vehicle is actually used is calculated using the above formula T 損失 =T 燃焼 +T ISG -T 回転トルク In addition, it is considered that the viscosity of the engine oil is different at different engine oil temperatures and different coolant temperatures, and the engine friction is different, and the engine loss torque is also different. Therefore, the engine loss torque T 損失-t It is very necessary to calculate

[0050] Therefore, referring to FIG. 7, in the present disclosure, at each engine start control, the engine oil temperature and the engine coolant temperature are recorded and calculated using the equation T 損失 =T 燃焼 +T ISG -T 回転トルク By using the torque loss T 損失-t is calculated, and T 損失-tis used as the environment-based adaptive self-learning value of the engine loss torque measured by using the drag inversion method, and the current preset correspondence between the engine oil temperature, engine coolant temperature, and loss torque is updated. In the subsequent actual use of the whole vehicle, when the engine is at the engine oil temperature and engine coolant temperature, the EMS will look up the corresponding T 損失-t and then use the corresponding T to interact with other controllers. 損失-t is sent to the vehicle bus as the engine loss torque. The updating may be performed by directly adding the engine oil temperature, engine coolant temperature, and corresponding actual loss torque to the current preset correspondence relationship if the currently recorded engine oil temperature and engine coolant temperature do not exist in the current preset correspondence relationship, or by replacing the existing engine oil temperature, engine coolant temperature, and corresponding actual loss torque in the current preset correspondence relationship if the currently recorded engine oil temperature and engine coolant temperature exist in the current preset correspondence relationship. In this way, the accuracy of the engine loss torque used in the hybrid electric vehicle can be ensured.

[0051] In some embodiments, controlling the ISG motor of the hybrid electric vehicle according to the work loss torque may include obtaining a target torque of the ISG motor according to the work loss torque, the rotational torque, and the combustion torque, and performing load control and unloading control on the ISG motor according to the target torque.

[0052] Specifically, the engine torque loss T 損失-t After being sent to the car bus, the ISG motor is controlled by the equation T ISG '=T 損失-t +T 回転トルク -T 燃焼 The target torque of the ISG motor can be determined according to the following equation.

[0053] In some embodiments, the control method for engine starting further includes determining whether the engine is in a constant speed rotation process according to the crankshaft angular velocity, and if the engine is in a constant speed rotation process, adjusting the fuel injection, ignition, and intake of the engine so that the ISG motor works smoothly, or if the engine is in a non-constant speed rotation process, determining the load gradient and unload gradient of the ISG motor according to the change in rotation torque, and performing load control of the ISG motor according to the load gradient and unload control of the ISG motor according to the unload gradient.

[0054] Specifically, in the engine constant speed rotation process, T 回転トルク is 0. In this case, steady-state operation can be further implemented by adjusting the engine's fuel injection, ignition, and intake, so that the ISG motor works smoothly and the load shock caused by voltage and current fluctuations is reduced. In the non-constant speed rotation process of the engine, T 回転トルク is not 0. In this case, the load gradient and unload gradient of the ISG motor can be determined according to the dynamic change of the rotational torque of the transmission shaft, resulting in better cooperation between the ISG motor and the engine, thereby improving the quality of the engine's speed fluctuation process. Determining the load gradient and unload gradient of the ISG motor according to the dynamic change of the rotational torque of the transmission shaft may be such that, in the loading process, when the rotational torque is 0, the load gradient is a constant value, and when the rotational torque is greater than 0, the load gradient decreases. In the unloading process, when the rotational torque is 0, the unload gradient is a constant value, and when the rotational torque is greater than 0, the unload gradient increases.

[0055] As shown in FIG. 8, after the unloading torque of the ISG motor is adjusted by using the method of the present disclosure, the position

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[0056] Based on the aforementioned control method for engine starting of a hybrid electric vehicle, the present disclosure further provides a computer-readable storage medium.

[0057] In this embodiment of the present application, a computer program is stored in a computer-readable storage medium, and when executed by a processor, a control method for engine starting of a hybrid electric vehicle is implemented.

[0058] The present disclosure further provides a controller.

[0059] FIG. 9 is a structural block diagram of a controller according to one embodiment of the present disclosure.

[0060] 9, the controller 900 includes a processor 901 and a memory 903. The processor 901 and the memory 903 are connected to each other via, for example, a bus 902. Alternatively, the controller 900 may further include a transceiver 904. It should be noted that in practical applications, the number of transceivers 904 is not limited to one, and the structure of the controller 900 does not constitute a limitation on this embodiment of the present disclosure.

[0061] The processor 901 may be a CPU (Central Processing Unit) or another general-purpose processor, a DSP (Digital Signal Processor), an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array) or other programmable logic device, a transistor logic device, a hardware component, or any combination thereof. The processor 901 may implement or execute various example logic blocks, modules, and circuits described in connection with this disclosure. Alternatively, the processor 901 may be a combination of processors that perform computing functions, such as a combination of one or more microprocessors or a combination of a DSP and a microprocessor.

[0062] The bus 902 may include channels for transmitting information between the aforementioned components. The bus 902 may be a PCI (Peripheral Component Interconnect) bus, an EISA (Extended Industry Standard Architecture) bus, etc. The bus 902 may be categorized into an address bus, a data bus, a control bus, etc. For ease of representation, only one thick line is used to represent a bus in FIG. 5, but this does not imply that there is only one bus or only one type of bus.

[0063] The memory 903 is configured to store a computer program corresponding to the control method for engine starting of a hybrid electric vehicle in the aforementioned embodiment of the present disclosure. The computer program is controlled and executed by the processor 901. The processor 901 is configured to execute the computer program stored in the memory 903 to implement the contents shown in the aforementioned method embodiment.

[0064] It should be noted that the controller 900 shown in FIG. 9 is merely an example and should not constitute any limitation on the functionality and scope of use of the embodiments of the present disclosure.

[0065] The present disclosure further provides a hybrid electric vehicle.

[0066] FIG. 10 is an architectural block diagram of a hybrid electric vehicle according to the present disclosure.

[0067] As shown in FIG. 10, a hybrid electric vehicle 1000 includes the engine 100, the ISG motor 200, and a controller 900 in the above-described embodiment.

[0068] In conclusion, according to the hybrid electric vehicle and its engine starting control method, medium, and controller of the disclosed embodiments, the actual loss torque during the engine rotation process is calculated using the initial torque of the ISG motor, the engine combustion torque, and the rotational torque of the transmission shaft. Meanwhile, the engine coolant temperature and engine oil temperature during operation are acquired, and the actual loss torque corresponding to these temperatures is used as an environment-based adaptive self-learning value to update the preset correspondence relationship stored in the EMS. Furthermore, in subsequent (next or several) engine start control, the engine loss torque is obtained by looking up the table according to the engine coolant temperature and engine oil temperature, and the work torque (i.e., target torque) of the ISG motor is back-calculated using a torque balance equation to control the engine start. Therefore, the engine loss torque used in the engine start control process is more accurate, resulting in more accurate ISG motor torque control, better cooperation between the ISG motor and the engine, and improved engine speed fluctuation quality.

[0069] It should be noted that the logic and / or steps illustrated in the flowcharts or otherwise described herein, e.g., ordered listings that may be considered as executable instructions used to implement logical functions, may be embodied in any computer-readable medium used by or in combination with an instruction execution system, apparatus, or device (e.g., a computer-based system, a system including a processor, or another system that can obtain instructions from and execute those instructions), or in combination with such an instruction execution system, apparatus, or device. In the context of this application, a "computer-readable medium" may be any device that can contain, store, communicate, propagate, or transmit a program used by or in combination with an instruction execution system, apparatus, or device. More specific examples (non-exhaustive list) of computer-readable media include an electrical connection having one or more wires (an electronic device), a portable computer diskette (a magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), a fiber optic device, and a portable compact disc read-only memory (CDROM). Additionally, the computer-readable medium may be paper or another suitable medium on which the program may be printed, so that the program may be obtained electronically, for example, by optically scanning the paper or other medium, and then editing and interpreting it, or processing it in another suitable manner as needed, and then storing the program in computer memory.

[0070] It should be understood that portions of the present disclosure may be implemented using hardware, software, firmware, or a combination thereof. In the above-described embodiments, some steps or methods may be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if hardware is used in the same embodiment as another embodiment, the embodiment may be implemented using any one or combination of the following techniques known in the art: discrete logic circuits of logic gate circuits for implementing logical functions of data signals, application-specific integrated circuits having appropriate combinational logic gate circuits, programmable gate arrays (PGAs), and field programmable gate arrays (FPGAs).

[0071] In the description herein, the use of reference terms such as "one embodiment," "some embodiments," "examples," "specific examples," "some examples," etc. means that the particular feature, structure, material, or characteristic described in combination with the embodiment(s) or example(s) is included in at least one embodiment or example of the present disclosure. As used herein, exemplary descriptions of the foregoing terms do not necessarily refer to the same embodiment or example. In addition, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more of the embodiments or examples.

[0072] In describing the present disclosure, it should be understood that the orientations or positions indicated by terms such as "center," "longitudinal," "transverse," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" are not intended to indicate or imply that the referenced devices or components must have a particular orientation or be constructed and operated in a particular orientation, but are based on the orientations or positions shown in the accompanying drawings and are used solely for ease and brevity of illustration and description. Accordingly, such terms should not be construed as limitations on the present disclosure.

[0073] Additionally, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying the relative importance or quantity of the indicated technical features. Thus, a feature qualified by "first" or "second" may explicitly indicate or implicitly include at least one of such features. In the description of this disclosure, unless otherwise specified, "plurality" means at least two, e.g., two or three.

[0074] It should be noted that in this disclosure, unless otherwise specified and limited, the terms "attach," "connect," "connection," and "secure" should be understood broadly. For example, unless otherwise specified, a connection may be a fixed connection, a detachable connection, or an integral connection, or a mechanical connection or an electrical connection, or a connection may be a direct connection, an indirect connection through an intermediary, or an internal communication between two elements, or an interactive relationship between two elements. Those skilled in the art can understand the specific meaning of the terms in this disclosure based on the specific situation.

[0075] In this disclosure, unless otherwise expressly specified or defined, a first feature being "above" or "below" a second feature may mean that the first feature is in direct contact with the second feature or that the first feature is in indirect contact with the second feature via an intermediate object. In addition, a first feature being "above," "over," or "on" a second feature may indicate that the first feature is directly above or diagonally above the second feature, or may simply indicate that the horizontal position of the first feature is higher than the horizontal position of the second feature. A first feature being "below," "under," and "beneath" a second feature may indicate that the first feature is directly below the second feature or at the slanted bottom of the second feature, or may simply indicate that the horizontal position of the first feature is lower than the horizontal position of the second feature.

[0076] Although the embodiments of the present disclosure have been illustrated and described above, it should be understood that the foregoing embodiments are examples and should not be understood as limitations on the present disclosure. Those skilled in the art may make changes, modifications, substitutions, or variations to the foregoing embodiments within the scope of the present disclosure.

Claims

1. 1. A control method for engine starting of a hybrid electric vehicle, the method comprising: obtaining an engine oil temperature and an engine coolant temperature after an engine start condition is satisfied; Searching a predetermined correspondence relationship according to the engine oil temperature and the coolant temperature to obtain the engine work loss torque; controlling an ISG motor of the hybrid electric vehicle according to the work loss torque to start the engine; A control method for starting an engine of a hybrid electric vehicle, comprising:

2. The method comprises: Obtaining a crank angle and a crankshaft angular velocity of the engine during the process of starting the engine; obtaining a combustion torque generated on an engine crankshaft by combustion gas in an engine cylinder according to the crank angle, and obtaining a rotational torque of a transmission shaft according to the crankshaft angular velocity; Obtaining an initial torque of the ISG motor, and obtaining an actual loss torque of the engine at the engine oil temperature and the coolant temperature according to the combustion torque, the rotational torque, and the initial torque; updating the preset correspondence relationship according to the actual torque loss; 10. The control method for engine starting of a hybrid electric vehicle of claim 1, further comprising:

3. The obtaining of the actual loss torque of the engine at the engine oil temperature and the coolant temperature according to the combustion torque, the rotational torque, and the initial torque includes: calculating a difference between the combustion torque and the rotational torque, calculating a sum of the difference and the initial torque, and using the sum as the actual loss torque; 3. The control method for starting an engine of a hybrid electric vehicle as recited in claim 2, comprising:

4. The combustion torque is obtained by using the following formula: T 燃焼 =p ｉ *s*cosβ*r*sin(α+β) In the ceremony, T 燃焼 is the combustion torque, β=arcsin(r*sinα / l), is the crankshaft connecting rod swing angle, l is the crankshaft connecting rod length, r is the crank radius, s is the surface area of ​​the piston head in the cylinder, α is the crank rotation angle, and p ｉ 4. The control method for starting an engine of a hybrid electric vehicle according to claim 2 or 3, wherein: is the combustion burst pressure in said cylinder.

5. The rotational torque is obtained by using the following formula: T トルク =J*a ｉ 、 In the ceremony, T トルク is the rotational torque, J is the moment of inertia of the transmission shaft, and a ｉ = (w ｉ -w ｉ－１ ) / t, where w is the crankshaft angular acceleration at the i-th time point, ｉ is the crankshaft angular velocity at the i-th time point, and t is the time difference between the i-th time point and the (i-1)-th time point.

6. The controlling of the ISG motor of the hybrid electric vehicle according to the work loss torque includes: Obtaining a target torque of the ISG motor according to the work loss torque, the rotational torque, and the combustion torque; performing load control and unload control on the ISG motor in accordance with the target torque; 6. A control method for starting an engine of a hybrid electric vehicle according to any one of claims 2 to 5, comprising:

7. The method comprises: Determining whether the engine is in a constant speed rotation process according to the crankshaft angular velocity; When the engine is in the constant speed rotation process, adjusting the fuel injection, ignition and intake of the engine so that the ISG motor works smoothly; or When the engine is in a non-constant speed rotation process, a load gradient and an unload gradient of the ISG motor are determined according to the change in the rotation torque, and the load control of the ISG motor is performed according to the load gradient, and the unload control of the ISG motor is performed according to the unload gradient.

7. The control method for engine starting of a hybrid electric vehicle of claim 6, further comprising:

8. 8. A computer-readable storage medium having a computer program stored thereon, the computer program, when executed by a processor, implementing the control method for engine starting of a hybrid electric vehicle according to any one of claims 1 to 7.

9. A controller comprising a memory, a processor and a computer program stored in said memory, said computer program, when executed by said processor, performing the method of any one of claims 1 to 7.

10. A hybrid electric vehicle comprising an engine, an ISG motor, and the controller of claim 9.

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