Engine start control method, device, and hybrid vehicle
By obtaining the crankshaft stop position of the hybrid vehicle engine and adjusting it to the target state, and using the generator to start with low torque, the problem of vehicle vibration caused by frequent engine start-stop is solved, and the smoothness of engine start and ride comfort are improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- DONGFENG MOTOR GRP
- Filing Date
- 2023-10-07
- Publication Date
- 2026-07-21
Smart Images
Figure CN117569957B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the technical field of engine control, and more particularly to an engine start-up control method, device, and hybrid vehicle. Background Technology
[0002] In a power-split hybrid configuration, the ring gear, planetary gear carrier, and sun gear are connected to different power sources such as the drive motor, generator, and engine via planetary gear sets to achieve continuously variable transmission (CVT) and decoupling of the speed and torque between the engine and the wheels, thus realizing power-split shifting in an ECVT (Electrically Controlled Continuously Variable Transmission). However, to adapt to different driving conditions, the operating mode of this configuration must be frequently switched, such as from pure electric drive to hybrid drive, from pure electric drive to direct drive mode, or series generator. During these switching processes, the crankshaft stops at inconsistent positions due to frequent engine start-stop cycles, which severely affects the overall driving smoothness and ride comfort.
[0003] Therefore, improving the smoothness of the engine start-up process in hybrid vehicles is a technical problem that urgently needs to be solved. Summary of the Invention
[0004] The present invention provides an engine start-up control method, device, and hybrid vehicle, which can improve the smoothness of the engine start-up process of hybrid vehicles.
[0005] The embodiments of the present invention provide the following solutions:
[0006] In a first aspect, embodiments of the present invention provide an engine start-up control method, applied to the engine start-up control of a hybrid vehicle, the method comprising:
[0007] Obtain the crankshaft stop position of the engine, where the crankshaft stop position is the position where the engine crankshaft stops rotating after the engine is turned off;
[0008] Determine whether the crankshaft stop position is the preset target position, where the target position is the position of the crankshaft when the engine starting torque is less than the preset value;
[0009] When the crankshaft is not in the target position, the generator connected to the engine is controlled to adjust the engine to the target state according to the operating conditions of the hybrid vehicle, so that the engine starts with a starting torque less than the preset value.
[0010] In one optional embodiment, obtaining the crankshaft stop position of the engine includes:
[0011] Obtain the rotor position signal output by a preset sensor, wherein the preset sensor is a rotary transformer connected to the crankshaft drive;
[0012] When the output frequency of the rotor position signal is lower than the preset frequency threshold, the rotor position signal is frequency multiplied to obtain the current rotor position.
[0013] The crankshaft stop position is determined based on the current rotor position and the preset position correspondence, where the position correspondence is the correspondence between the rotor position of the rotary transformer and the crankshaft position.
[0014] In one optional embodiment, the engine is started when the generator connected to the engine is adjusted to a target state according to the operating conditions of the hybrid vehicle, including:
[0015] When the operating condition is a shutdown condition, the generator is controlled to adjust the crankshaft to the target position according to the crankshaft stop position;
[0016] Once the crankshaft has rotated to the target position, the engine is confirmed to be in the target state, and the engine is ignited and started.
[0017] In one optional embodiment, the engine is started when the generator connected to the engine is adjusted to a target state according to the operating conditions of the hybrid vehicle, including:
[0018] When the operating condition is driving, the generator is controlled to drive the engine to rotate.
[0019] When the engine reaches the preset target speed and the crankshaft reaches the target position, the engine is determined to be in the target state, and the engine is ignited and started.
[0020] In one alternative embodiment, controlling the generator to drive the engine to rotate includes:
[0021] The generator is controlled to drive the engine to rotate based on a preset initial torque, and the acceleration deviation of the hybrid vehicle under driving conditions is obtained.
[0022] The compensation torque for driving the engine is determined based on the acceleration deviation;
[0023] Based on the sum of the initial torque and the compensation torque, the generator is controlled to drive the engine to rotate at a preset speed curve.
[0024] In an optional embodiment, before controlling the generator to drive the engine to rotate at a preset speed curve, the method further includes:
[0025] According to the formula Obtain the preset speed curve, where J is the engine's operating speed. This refers to the engine's real-time angular velocity. This refers to the engine's idle angular velocity. λ1 represents the vibration angle deviation of the engine during a preset period T, where λ1 is a preset first coefficient and λ2 is a preset second coefficient.
[0026] Secondly, embodiments of the present invention also provide a hybrid vehicle, wherein the hybrid vehicle controls the engine start-up via any of the methods described in the first aspect.
[0027] Thirdly, embodiments of the present invention also provide an engine control device for engine start-up control in hybrid vehicles, the device comprising:
[0028] The acquisition module is used to acquire the crankshaft stop position of the engine, where the crankshaft stop position is the position where the engine crankshaft stops rotating after the engine is turned off;
[0029] The judgment module is used to determine whether the crankshaft stop position is a preset target position, where the target position is the position of the crankshaft when the engine starting torque is less than a preset value;
[0030] The control module is used to control the generator connected to the engine to adjust the engine to the target state and start the engine according to the operating conditions of the hybrid vehicle when the crankshaft is not in the target position, so that the engine starts with a starting torque less than a preset value.
[0031] Fourthly, embodiments of the present invention also provide an electronic device, including a processor and a memory, the memory being coupled to the processor, the memory storing instructions that, when executed by the processor, cause the electronic device to perform the steps of any of the methods in the first aspect.
[0032] Fifthly, embodiments of the present invention also provide a computer-readable storage medium having a computer program stored thereon that, when executed by a processor, implements the steps of any of the methods in the first aspect.
[0033] The engine start-up control method, device, and hybrid vehicle of the present invention have the following advantages compared with the prior art:
[0034] The starting control method of this invention obtains the crankshaft stop position of the engine and determines whether the crankshaft stop position is a preset target position. Since the target position is the position of the crankshaft when the engine's starting torque is less than a preset value, if the crankshaft stop position is not at the target position, it means that directly starting the engine will cause large vibrations due to excessive starting resistance. Therefore, according to the operating conditions of the hybrid vehicle, the generator connected to the engine is controlled to adjust the engine to the target state and start the engine, so that the engine starts with a starting torque less than the preset value. Since the starting torque is smaller, the reaction force during the engine starting process will be reduced accordingly, which can reduce the vibration during the engine starting process. When applied to the engine starting control of hybrid vehicles, this improves the smoothness of the engine starting process of hybrid vehicles. Attached Figure Description
[0035] To more clearly illustrate the technical solutions in the embodiments of this specification or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this specification. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0036] Figure 1 A flowchart illustrating an engine start-up control method provided in an embodiment of the present invention;
[0037] Figure 2 This is a power source architecture diagram of a hybrid vehicle provided in an embodiment of the present invention;
[0038] Figure 3 This is a schematic diagram of the structure of a hybrid power transmission provided in an embodiment of the present invention;
[0039] Figure 4 A schematic diagram illustrating the logic of engine drag torque self-learning provided in an embodiment of the present invention;
[0040] Figure 5 This is a schematic diagram of the structure of an engine start control device provided in an embodiment of the present invention. Detailed Implementation
[0041] 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. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the protection scope of the embodiments of the present invention.
[0042] Please see Figure 1 , Figure 1This invention provides a flowchart of an engine start-up control method, applicable to engine start-up control of a hybrid vehicle. It can be implemented based on the vehicle control unit (VCU) of the hybrid vehicle, or on other control terminals on the hybrid vehicle, as long as the control method can be run. The control method includes:
[0043] S11. Obtain the crankshaft stop position of the engine, where the crankshaft stop position is the position where the engine crankshaft stops rotating after the engine is turned off.
[0044] Specifically, when a hybrid vehicle reaches its destination or requires a mode switch, the vehicle controller will shut down the engine. After the engine shuts down, the crankshaft's stopping position can be determined using sensors installed on the engine, such as the signal output from the crankshaft sensor.
[0045] In practical applications, due to the low resolution of crankshaft sensors in detecting crankshaft angles, determining the crankshaft stop position based on the signal output by the crankshaft sensor suffers from insufficient accuracy. Therefore, in one specific embodiment, obtaining the engine crankshaft stop position includes:
[0046] The first step is to acquire the rotor position signal output by a preset sensor, which is a rotary transformer connected to the crankshaft drive. The rotary transformer can be directly mounted on the engine or on the generator. The generator's rotor triggers the output of the rotor position signal, and the rotary transformer synchronously outputs the rotor position signal based on the crankshaft's rotation, providing real-time rotor position signal output during crankshaft rotation. The rotor position signal determines the crankshaft's rotational position, and subsequently, the engine's piston position, for subsequent cylinder identification. Replacing the traditional crankshaft sensor with a rotary transformer yields better measurement accuracy.
[0047] The second step involves frequency multiplication of the rotor position signal when its output frequency falls below a preset threshold to obtain the current rotor position. A low output frequency indicates low engine speed, potentially leading to insufficient cylinder detection accuracy. Therefore, frequency multiplication is necessary. The multiplication factor can be set according to actual needs, such as doubling the frequency. This effectively improves the accuracy of determining the current rotor position, thereby enhancing cylinder detection accuracy.
[0048] The third step is to determine the crankshaft stopping position based on the current rotor position and the preset position correspondence. This position correspondence refers to the relationship between the rotor position of the rotary transformer and the crankshaft position. After the rotary transformer is connected to the crankshaft, there is a correspondence between the rotor position and the crankshaft position. Therefore, the crankshaft position can be found based on the current rotor position according to this correspondence. When the crankshaft stops rotating, the crankshaft stopping position can be determined based on the crankshaft position corresponding to the current rotor position.
[0049] It should be noted that when identifying cylinders in an engine, the crankshaft rotation angle can be determined by sequential counting based on the rotor position signal. A position correspondence is established based on the correspondence between the crankshaft rotation angle and the cylinder sequence. Finally, based on the two long teeth and two short teeth of the engine's camshaft, the final identification and determination of one cylinder is made. This allows for precise detection of the cylinder stop position and crankshaft rotation angle in the low-speed range of the engine, and outputs the crankshaft stop position to determine the magnitude of the subsequent starting torque.
[0050] When determining the cylinder position of the engine, first calibrate the missing tooth position of the crankshaft and the two long teeth and two short teeth of the camshaft, corresponding to the top dead center of the compression stroke of cylinder one, and mark them on the flywheel end; mark the rotor shaft end where the generator connects to the engine flywheel end, and align it with the marked position on the engine flywheel end; fix the crankshaft and generator rotor shaft as a whole, and apply voltage vectors of different angles to the three phase terminals U, V, and W of the generator stator respectively. Adjust the stator position of the rotary transformer so that the angle calculated by the rotary transformer is zero, and then fix the rotary transformer to complete the overall zeroing of the engine and generator. During crankshaft rotation, the rotary transformer generates a rotor position signal representing the mechanical angle of the motor rotor: Q1 = Q2 / P + N*360 / P, where Q1 represents the mechanical angle of the motor rotor, Q2 is the electrical angle of a single pole motor rotor, N = 1, 2, 3, ... P-1, and P is the number of motor pole pairs. Based on the envelope signal of the motor rotation angle, N automatically increments by 1 for each cycle until it reaches a maximum of P-1, then starts accumulating from 0 again. On the test bench, based on the mechanical speed ratio between the engine and the generator, the camshaft angle at the top dead center (TDC) position of cylinder one of the engine within one cycle is correlated with the mechanical angle of the generator rotor. Each time the generator's mechanical angle reaches a marked angle, the GCU (Generator Control Unit) considers that cylinder one of the engine has also reached TDC. Once the TDC position of cylinder one is confirmed, the positions of cylinders two, three, and four can also be confirmed. Based on the accumulated rotation angle of the generator, interruption events such as the cylinder injection start position and ignition angle are designed and triggered in the engine control timing. The crankshaft position during engine operation can be accurately determined using the above method. When the engine stops running, the crankshaft stopping position is determined based on the rotor position signal. After obtaining the crankshaft stopping position, proceed to step S12.
[0051] S12. Determine whether the crankshaft stop position is the preset target position, where the target position is the position of the crankshaft when the engine starting torque is less than the preset value.
[0052] Specifically, since an engine has four strokes—intake, compression, expansion, and exhaust—the required starting torque varies across these strokes. The reaction force is greatest at the end of the compression stroke, so starting should be avoided during this phase. Calibration experiments can determine the correspondence between different crankshaft stop positions and starting torques, allowing for the setting of a target position. It's understood that the increased compression torque in the latter half of the compression stroke leads to increased compression volume; therefore, the target position can be set at the beginning of the compression stroke. For four-cylinder engines, setting the target position requires considering the overall rotation angle of all four cylinders. For example, the top dead center of a cylinder piston. When a cylinder piston is near top dead center, the intake and exhaust strokes of other cylinders have almost no impact on the engine's friction torque. To determine if the crankshaft stop position is the target position, both can be represented as crankshaft rotation angles. Comparing these angle values confirms whether the crankshaft stop position is indeed the target position. When the crankshaft stops at the target position, it means that the engine will not vibrate due to the impact of reciprocating inertial force during startup, so no other control is executed; otherwise, when the crankshaft stops at the target position, step S13 is executed.
[0053] S13. When the crankshaft is not in the target position at the stop position, the generator connected to the engine is controlled to adjust the engine to the target state according to the operating conditions of the hybrid vehicle, so that the engine starts with a starting torque less than the preset value.
[0054] Specifically, the target state is the state in which the engine starts with a starting torque less than a preset value. The operating condition characterizes the current operating state of the hybrid vehicle, which can be divided into parking condition (when the vehicle is stationary) and driving condition (when the vehicle is in motion). Taking the parking condition as an example, the generator can be controlled to adjust the crankshaft to the target position based on the crankshaft's stop position. When the crankshaft rotates to the target position, the engine is determined to be in the target state, and the engine is ignited and started. In the parking condition, the engine's operating condition can be further assessed. When the engine is in the off condition, if a driver-controlled shutdown command is received, a first torque signal can be output to the generator based on the shutdown command and the crankshaft's stop position, causing the crankshaft to rotate to the target position under the off condition. When the engine is in the starting condition, if a driver-controlled start command is received, a second torque signal can be output to the generator based on the start command and the crankshaft's stop position, causing the crankshaft to rotate to the target position under the starting condition.
[0055] To reduce redundant calculations during engine start-up control, the relationship between the rotor position signal and the engine cylinder sequence can be used to dynamically guide the final cylinder deactivation position via GCU dragging. This optimizes the cylinder deactivation position to be near the crankshaft angle corresponding to the target position, thereby reducing the impact of reciprocating inertial forces during the initial dragging process. The engine dragging torque is stored inside the GCU so that in subsequent engine control, after obtaining the crankshaft stop position, the corresponding dragging torque can be determined based on the stored results to drag the engine to the target position for start-up.
[0056] Please see Figure 2 and Figure 3 , Figure 2 This is a diagram of the power source architecture for a hybrid vehicle. Figure 3 This is a schematic diagram of a hybrid transmission. The engine connects to the generator (or P1 motor) and the differential via a planetary carrier, ring gear, and sun gear. Therefore, a hybrid vehicle can be driven by the engine, the drive motor (or P3 motor), or both. Thus, hybrid vehicles have multiple power output modes. When switching modes during vehicle operation, the engine needs to start or stop, which involves significant vibration. At low engine speeds, the transition time between strokes is longer, resulting in more pronounced impact vibrations caused by friction. Friction variations hinder the engine's convergence towards shutdown, further increasing vehicle vibration.
[0057] The following section will explain in detail how to adjust the engine to the target state for starting, taking the operating condition as the driving condition, in order to improve the smoothness of the engine starting process.
[0058] The first step, when the operating condition is driving, is to control the generator to drive the engine. In driving mode, if a power output mode switching command is received, indicating a need to start the engine, a preset initial torque can be sent to the generator based on the engine's set initial torque, which then drives the engine. The initial torque can be set based on different crankshaft stop positions to drive the engine in driving mode.
[0059] In practical applications, because the vehicle's operating state changes in real time during driving, controlling the generator to drive the engine based on the initial torque has the problem of insufficient accuracy in torque output. Therefore, self-learning is required to determine the driving torque. For example, controlling the generator to drive the engine includes:
[0060] The generator is controlled to drive the engine based on a preset initial torque, and the acceleration deviation of the hybrid vehicle under driving conditions is obtained. When the engine is not ignited, the engine rotation is provided by the generator torque; the engine does not provide output torque to the vehicle wheels, and the engine speed and generator speed conform to the mechanical transmission ratio. The acceleration deviation can be calculated in real time based on the hybrid vehicle's driving process; the acceleration deviation is the deviation between the vehicle acceleration issued by the vehicle controller and the actual vehicle acceleration. To obtain good start-up smoothness, the compensation torque for driving the engine is determined based on the acceleration deviation. The correspondence between acceleration deviation and compensation torque can be obtained through calibration experiments, and then the compensation torque is determined based on the current acceleration deviation. The compensation torque represents the compensation value required to ensure smooth start-up after applying the initial torque to drive the engine. Based on the sum of the initial torque and the compensation torque, the generator is controlled to drive the engine at a preset speed curve.
[0061] In practical applications, it is necessary to obtain the optimal engine start-up speed curve for best ride comfort, i.e., the preset speed curve. Then, feedforward control based on the preset speed curve is used to compensate for the GCU's drag torque, and feedback control is used to improve control accuracy. During the start-up process, the GCU should coordinate the generator torque to bring the engine to idle speed as quickly as possible and achieve optimal ride comfort. Before controlling the generator to drive the engine at the preset speed curve, the method also includes:
[0062] According to the formula Obtain the preset speed curve, where J is the engine's operating speed. This refers to the engine's real-time angular velocity. This refers to the engine's idle angular velocity. The vibration angle deviation of the engine during a preset period T is λ1, which can be freely set according to actual needs. λ1 is the preset first coefficient, and λ2 is the preset second coefficient. λ1 and λ2 can be determined through actual vehicle calibration tests. This represents the angular deviation between the actual engine angular velocity and the desired angular velocity. This represents the angular deviation caused by vibration during engine startup, and is an indicator of vehicle bumpiness. The formula above allows for controlling the engine to rotate at the optimal speed, achieving minimal speed error during engine startup, and ensuring the best driving comfort.
[0063] To further ensure the smoothness of engine starting, the operating speed can be updated based on the cooling factor correction coefficient. Similarly, the relationship between engine speed, coolant temperature and cooling factor correction coefficient is obtained through calibration experiments. Based on the above formula, the engine operating speed J is obtained. Then, based on the formula J0=Jσ, the operating speed is updated, where σ is the cooling factor correction coefficient. After the generator drives the engine to rotate, the process proceeds to the next step.
[0064] The second step is to determine that the engine is in the target state when it reaches the preset target speed and the crankshaft reaches the target position, and then ignite the engine. The target speed can be a corresponding value on a preset speed curve. When the engine reaches the target speed based on the torque output by the generator, it indicates that a smooth start can be performed, and the engine is ignited when the crankshaft reaches the target position.
[0065] The following section will provide an overview of how self-learning control of torque is performed during vehicle operation. Please refer to [link / reference needed]. Figure 4 , Figure 4 This is a logic diagram illustrating the self-learning of engine torque. The first step is to determine if the engine has entered a shutdown process. If not, the process ends; if so, proceed to the next step. The second step records the specific cylinder deactivation position after shutdown and proceeds to the next step. The third step uses a preset torque for the next start-up, then proceeds to the next step. The fourth step records the vibration during startup and proceeds to the next step. The fifth step combines the recorded vibration data from starting with the current torque, optimizes the starting torque corresponding to the shutdown position, and feeds it back to the third step. This learning cycle continues until the starting vibration requirements are met, at which point the process ends.
[0066] When starting the engine while the vehicle is in motion, the first step is to generate a torque map based on the crankshaft stop position, engine speed, and initial torque. The crankshaft stop position and engine speed are read, and the initial torque is used to drive the engine to rotate. The second step is to obtain the acceleration deviation based on the deviation between the target acceleration and the actual acceleration. The actual acceleration is calculated based on the actual drive motor speed fluctuation, and the target acceleration is calculated based on the generator speed corresponding to the preset speed curve. Finally, the compensation torque is calculated. The third step is to use the preset speed curve as the target speed for engine dragging and output an appropriate dragging torque. When the dragging torque is reached and the speed is at the target speed, and the crankshaft rotates to the target position, the engine is determined to be in the target state, and the engine is ignited and started.
[0067] Based on the same inventive concept as the control method, this embodiment of the invention also provides a hybrid vehicle, wherein the hybrid vehicle controls the engine start-up via any of the control methods.
[0068] Based on the same inventive concept as the control method, embodiments of the present invention also provide an engine control device applied to engine start control in hybrid vehicles. Please refer to [link to relevant documentation]. Figure 5 , Figure 5 This is a schematic diagram of the control device, which includes:
[0069] The acquisition module 501 is used to acquire the crankshaft stop position of the engine, wherein the crankshaft stop position is the position where the crankshaft of the engine stops rotating after the engine is turned off;
[0070] The judgment module 502 is used to determine whether the crankshaft stop position is a preset target position, wherein the target position is the position of the crankshaft when the engine starting torque is less than a preset value;
[0071] The control module 503 is used to control the generator connected to the engine to adjust the engine to the target state and start the engine according to the operating conditions of the hybrid vehicle when the crankshaft stop position is not at the target position, so that the engine starts with a starting torque less than a preset value.
[0072] In one optional embodiment, the acquisition module includes:
[0073] The acquisition submodule is used to acquire the rotor position signal output by a preset sensor, wherein the preset sensor is a rotary transformer connected to the crankshaft drive;
[0074] The processing submodule is used to perform frequency multiplication processing on the rotor position signal when the output frequency of the rotor position signal is lower than a preset frequency threshold in order to obtain the current rotor position.
[0075] The determination submodule is used to determine the crankshaft stop position based on the current rotor position and the preset position correspondence, where the position correspondence is the correspondence between the rotor position of the rotary transformer and the crankshaft position.
[0076] In one optional embodiment, the control module includes:
[0077] The first control submodule is used to control the generator to adjust the crankshaft to the target position according to the crankshaft stop position when the operating condition is the shutdown condition.
[0078] The first start-up submodule is used to determine that the engine is in the target state when the crankshaft rotates to the target position, and to ignite and start the engine.
[0079] In an optional embodiment, the control module further includes:
[0080] The second control submodule is used to control the generator to drive the engine to rotate when the operating condition is driving condition;
[0081] The second start-up submodule is used to determine that the engine is in the target state when the engine rotates to the preset target speed and the crankshaft rotates to the target position, and then ignites and starts the engine.
[0082] In one optional embodiment, the second control submodule includes:
[0083] The control acquisition unit is used to control the generator to drive the engine to rotate based on a preset initial torque, and to acquire the acceleration deviation of the hybrid vehicle under driving conditions.
[0084] The determination unit is used to determine the compensation torque of the driving engine based on the acceleration deviation;
[0085] The control unit is used to control the generator to drive the engine to rotate according to a preset speed curve based on the sum of the initial torque and the compensation torque.
[0086] In an optional embodiment, the second control submodule further includes:
[0087] Obtaining a unit, used according to the formula Obtain the preset speed curve, where J is the engine's operating speed. This refers to the engine's real-time angular velocity. This refers to the engine's idle angular velocity. λ1 represents the vibration angle deviation of the engine during a preset period T, where λ1 is a preset first coefficient and λ2 is a preset second coefficient.
[0088] Based on the same inventive concept as the control method, embodiments of the present invention also provide an electronic device, including a processor and a memory, the memory being coupled to the processor, the memory storing instructions, which, when executed by the processor, cause the electronic device to perform the steps of any of the control methods.
[0089] Based on the same inventive concept as the control method, embodiments of the present invention also provide a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of any one of the methods in the control method.
[0090] The technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages:
[0091] The start-up control method obtains the crankshaft stop position of the engine and determines whether the crankshaft stop position is the preset target position. Since the target position is the position of the crankshaft when the engine's starting torque is less than the preset value, if the crankshaft stop position is not at the target position, it means that directly starting the engine will cause large vibrations due to excessive starting resistance. Therefore, according to the operating conditions of the hybrid vehicle, the generator connected to the engine is controlled to adjust the engine to the target state and start the engine, so that the engine starts with a starting torque less than the preset value. Since the starting torque is smaller, the reaction force during the engine starting process will be reduced accordingly, which can reduce the vibration during the engine starting process. When applied to the engine start-up control of hybrid vehicles, this improves the smoothness of the engine starting process of hybrid vehicles.
[0092] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.
[0093] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (modules, systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.
[0094] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.
[0095] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.
[0096] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.
[0097] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.
Claims
1. A method for starting and controlling an engine, characterized in that, An engine start control method applied to hybrid vehicles, the method comprising: Obtain the crankshaft stop position of the engine, wherein the crankshaft stop position is the position where the crankshaft of the engine stops rotating after the engine is turned off; Determine whether the crankshaft stop position is a preset target position, wherein the target position is the position of the crankshaft when the engine starting torque is less than a preset value; When the crankshaft stop position is not at the target position, the generator connected to the engine is controlled to adjust the engine to the target state according to the operating conditions of the hybrid vehicle, so that the engine is started with a starting torque less than the preset value; The step of starting the engine when the generator connected to the engine is adjusted to a target state according to the operating conditions of the hybrid vehicle includes: When the operating condition is driving condition, the generator is controlled to drive the engine to rotate based on a preset initial torque, and the acceleration deviation of the hybrid vehicle in the driving condition is obtained; the compensation torque for driving the engine is determined based on the acceleration deviation; based on the sum of the initial torque and the compensation torque, the generator is controlled to drive the engine to rotate at a preset speed curve. When the engine rotates to the preset target speed and the crankshaft rotates to the target position, the engine is determined to be in the target state, and the engine is ignited and started. Before controlling the generator to drive the engine to rotate according to a preset speed curve, according to the formula The preset rotational speed curve is obtained; in, The operating speed of the engine. The real-time angular velocity of the engine. The idle angular velocity of the engine. For the engine in a preset cycle T Vibration angle deviation, The first preset coefficient, This is the preset second coefficient.
2. The engine start-up control method according to claim 1, characterized in that, The process of obtaining the crankshaft stop position of the engine includes: Obtain the rotor position signal output by a preset sensor, wherein the preset sensor is a rotary transformer connected to the crankshaft drive; When the output frequency of the rotor position signal is lower than a preset frequency threshold, the rotor position signal is subjected to frequency multiplication to obtain the current rotor position. The crankshaft stop position is determined based on the current rotor position and the preset position correspondence, wherein the position correspondence is the correspondence between the rotor position of the rotary transformer and the crankshaft position.
3. The engine start-up control method according to claim 1, characterized in that, The step of starting the engine when the generator connected to the engine is adjusted to a target state according to the operating conditions of the hybrid vehicle includes: When the operating condition is a shutdown condition, the generator is controlled to adjust the crankshaft to the target position according to the crankshaft stop position; When the crankshaft rotates to the target position, the engine is determined to be in the target state, and the engine is ignited and started.
4. A hybrid vehicle, characterized in that, The hybrid vehicle controls engine start-up using the method described in any one of claims 1-3.
5. An engine starting control device, characterized in that, An engine start control device for use in hybrid vehicles, the device comprising: The acquisition module is used to acquire the crankshaft stop position of the engine, wherein the crankshaft stop position is the position where the crankshaft of the engine stops rotating after the engine is turned off; The judgment module is used to determine whether the crankshaft stop position is a preset target position, wherein the target position is the position of the crankshaft when the starting torque of the engine is less than a preset value; The control module is used to control the generator connected to the engine to adjust the engine to the target state and start the engine according to the operating conditions of the hybrid vehicle when the crankshaft stop position is not at the target position, so that the engine starts with a starting torque less than the preset value. The step of starting the engine when the generator connected to the engine is adjusted to a target state according to the operating conditions of the hybrid vehicle includes: When the operating condition is driving condition, the generator is controlled to drive the engine to rotate based on a preset initial torque, and the acceleration deviation of the hybrid vehicle in the driving condition is obtained; the compensation torque for driving the engine is determined based on the acceleration deviation; based on the sum of the initial torque and the compensation torque, the generator is controlled to drive the engine to rotate at a preset speed curve. When the engine rotates to the preset target speed and the crankshaft rotates to the target position, the engine is determined to be in the target state, and the engine is ignited and started. Before controlling the generator to drive the engine to rotate according to a preset speed curve, according to the formula The preset rotational speed curve is obtained; in, The operating speed of the engine. The real-time angular velocity of the engine. The idle angular velocity of the engine. For the engine in a preset cycle T Vibration angle deviation, The first preset coefficient, This is the preset second coefficient.
6. An electronic device, characterized in that, The device includes a processor and a memory, the memory being coupled to the processor, the memory storing instructions that, when executed by the processor, cause the electronic device to perform the steps of the method according to any one of claims 1-3.
7. A computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by a processor, the program implements the steps of the method described in any one of claims 1-3.