Vehicle torque control method and device under failure of electric VVT (Variable Valve Timing) and vehicle

Abstract

The invention relates to the technical field of vehicles, in particular to a whole vehicle torque control method and device under the failure of an electric VVT and a vehicle, and the method comprises the steps that when the current state of an electric variable valve timing system of the vehicle is a fault state, the current rotating speed of an engine and the current required torque of the vehicle are obtained, and based on the current rotating speed and / or the current required torque, the vehicle torque is controlled; and determining a target regression position and an optimal torque upper limit of the engine at the target regression position from the pre-calibrated MAP, so as to perform torque control on the vehicle according to the current demand torque and the optimal torque upper limit. Therefore, the problems that when the electric VVT is in the failure state, an engine flames out, a battery cannot be charged, and a vehicle cannot walk until the electric quantity is used up are solved, after the electric VVT fails, the motor torque is adjusted according to the maximum torque capacity and the minimum torque capacity at different rotating speeds by optimizing and calibrating the inflation model and the torque model at the two-pole positions, and therefore the electric VVT is more accurate. Direct engine flameout is avoided, and user requirements are met.

Description

Technical Field

[0001] The present application relates to the field of vehicle technology, and in particular to a method, device and vehicle for controlling vehicle torque under electric VVT (Variable Valve Timing) failure. Background Art

[0002] With the development of the automotive industry, VVT technology has been widely used in engines to improve fuel economy and power performance, especially electric VVT, namely EVVT (Electric Variable Valve Timing). Due to its advantages such as fast response speed and high precision, it has gradually become an important part of modern engines. However, when the EVVT system fails, EVVT cannot obtain effective timing signals, which will cause EVVT control failure and bring safety hazards.

[0003] In related technologies, when the EVVT fails, the EVVT will return to its initial position under the action of the motor. At this time, the EMS (Engine Management System) will report a fuel injection prohibition request to the HCU (Hybrid Control Unit), and the engine will quickly shut down. At the same time, the vehicle will report a serious hybrid system failure, and the vehicle can only rely on the battery to maintain operation.

[0004] However, when the engine is off, the battery cannot be charged and the user's power needs cannot be responded to. Once the battery is exhausted, the vehicle will be completely unable to drive, posing a safety hazard and affecting the user's riding experience, which urgently needs to be resolved. Summary of the Invention

[0005] The present application provides a method, device and vehicle for controlling the torque of a whole vehicle under failure of an electric VVT, so as to solve the problem that when the electric VVT is in a failed state, the engine is shut down and the battery cannot be charged, and the battery is exhausted, causing the vehicle to be unable to move, thereby affecting the user experience.

[0006] A first embodiment of the present application provides a method for controlling vehicle torque when an electric VVT fails, comprising the following steps: Get the current status of the vehicle's electric variable valve timing system; When the current state is a fault state, obtaining a current engine speed and a current required torque of the vehicle, and determining a target return position and an optimal upper torque limit and an optimal lower torque limit of the engine at the target return position from a pre-calibrated map based on the current engine speed and / or the current required torque; The vehicle is torque controlled according to the current required torque and an optimal torque upper limit of the engine at the target return position.

[0007] Furthermore, in some embodiments, before determining the target return position and the optimal upper torque limit and the optimal lower torque limit of the target return position from a pre-calibrated MAP based on the current speed and / or the current required torque, the method further includes: Based on the preset combustion stability requirements and the preset torque accuracy requirements, the engine's optimal ignition angle, optimal injection phase, optimal injection ratio, optimal ignition angle correction value at different coolant temperatures, minimum ignition angle, and minimum load are obtained; Based on different speeds, the optimal ignition angle, the optimal injection phase, the optimal injection ratio, the optimal ignition angle correction value at different coolant temperatures, the minimum ignition angle, and the minimum load, the electric variable valve timing system is determined to determine the optimal torque upper limit and the optimal torque lower limit of the engine when in the first position and the second position, thereby obtaining the pre-calibrated MAP.

[0008] Furthermore, in some embodiments, determining the target return position and the optimal upper torque limit and the optimal lower torque limit of the engine at the target return position from a pre-calibrated MAP based on the current speed and the current required torque includes: Determining whether the current required torque is greater than a preset torque; When the current required torque is greater than the preset torque, the target return position is determined to be the first position, and the optimal torque upper limit of the engine at the target return position is determined based on the current speed; otherwise, the target return position is determined to be the second position, and the optimal torque lower limit of the engine at the target return position is determined based on the current speed.

[0009] Furthermore, in some embodiments, the performing torque control on the vehicle according to the current required torque and the optimal torque upper limit of the engine at the target return position includes: Calculating a difference between the current required torque and an upper limit of an optimal torque of the engine at the target return position; If the difference is greater than the upper limit of the motor output torque of the vehicle, the vehicle is torque controlled based on the upper limit of the motor output torque and the optimal torque upper limit of the engine at the target return position; otherwise, while the engine is controlled based on the optimal torque upper limit control of the engine at the target return position to output torque, the motor of the vehicle is controlled to output torque based on the difference.

[0010] Furthermore, in some embodiments, after determining that the difference is greater than the upper limit of the motor output torque of the vehicle, the method further includes: Generate torque limit reminder information; Based on the torque limit reminder information, the vehicle is controlled to perform a torque limit reminder.

[0011] Furthermore, in some embodiments, obtaining the current state of the vehicle's electric variable valve timing system includes: Acquiring a crankshaft position, a cam position, a current voltage of the electric variable valve timing system, and a current CAN communication signal of the electric variable valve timing system; If any one of the crankshaft position, the cam position, the current voltage, and the current CAN communication signal is an invalid signal, it is determined that the current state of the electric variable valve timing system is the fault state.

[0012] According to the vehicle torque control method for electric variable valve timing (EVV) failure in an embodiment of the present application, when the vehicle's electric variable valve timing system is in a faulty state, the current engine speed and the vehicle's current required torque are obtained. Based on the current speed and / or current required torque, a target return position and the engine's optimal torque upper limit at the target return position are determined from a pre-calibrated map, thereby controlling the vehicle's torque according to the current required torque and the optimal torque upper limit. This method solves the problem of the engine stalling and battery failure when the electric variable valve timing (EVV) fails, leading to battery depletion and vehicle immobility. After the electric variable valve timing (EVV) fails, the method optimizes the inflation and torque models at the two calibrated extreme positions, adjusting the motor torque based on the maximum and minimum torque capabilities at different speeds to avoid direct engine stall and meet user needs.

[0013] A second embodiment of the present application provides a vehicle torque control device under electric VVT failure, comprising: An acquisition module, used to acquire a current state of an electric variable valve timing system of a vehicle; a determination module configured to obtain, when the current state is a fault state, a current engine speed and a current required torque of the vehicle, and determine, based on the current engine speed and / or the current required torque, a target return position and an optimal upper torque limit and an optimal lower torque limit of the engine at the target return position from a pre-calibrated map; A control module is configured to perform torque control on the vehicle according to the current required torque and an upper limit of an optimal torque of the engine at the target return position.

[0014] Furthermore, in some embodiments, before determining the target return position and the optimal upper torque limit and the optimal lower torque limit of the target return position from a pre-calibrated MAP based on the current speed and / or the current required torque, the determining module further includes: a first acquisition unit, configured to acquire an optimal ignition angle, an optimal injection phase, an optimal injection ratio, an optimal ignition angle correction value at different coolant temperatures, a minimum ignition angle, and a minimum load of the engine based on a preset combustion stability requirement and a preset torque accuracy requirement; The first determining unit is configured to determine, based on different speeds, the optimal ignition angle, the optimal injection phase, the optimal injection ratio, the optimal ignition angle correction value at different coolant temperatures, the minimum ignition angle, and the minimum load, the optimal upper torque limit and the optimal lower torque limit of the engine when the electrically variable valve timing system is in a first position and a second position, thereby obtaining the pre-calibrated MAP.

[0015] Furthermore, in some embodiments, the determining module includes: a judging unit, configured to judge whether the current required torque is greater than a preset torque; The second determination unit is used to determine that the target return position is the first position when the current required torque is greater than the preset torque, and determine the optimal torque upper limit of the engine at the target return position according to the current speed; otherwise, determine that the target return position is the second position, and determine the optimal torque lower limit of the engine at the target return position according to the current speed.

[0016] Furthermore, in some embodiments, the control module includes: a calculation unit, configured to calculate a difference between the current required torque and an upper limit of an optimal torque of the engine at the target return position; A control unit is configured to perform torque control on the vehicle based on the motor output torque upper limit and the optimal torque upper limit of the engine at the target return position if the difference is greater than the motor output torque upper limit of the vehicle; otherwise, while controlling the engine to output torque based on the optimal torque upper limit of the engine at the target return position, control the motor of the vehicle to output torque based on the difference.

[0017] Furthermore, in some embodiments, after determining that the difference is greater than an upper limit of the motor output torque of the vehicle, the control unit further includes: A generating subunit, used for generating torque limit reminder information; The control subunit is used to control the vehicle to perform a torque limit reminder based on the torque limit reminder information.

[0018] Furthermore, in some embodiments, the acquisition module includes: a second acquiring unit, configured to acquire a crankshaft position, a cam position, a current voltage of the electric variable valve timing system, and a current CAN communication signal of the electric variable valve timing system; A determination unit is configured to determine that the current state of the electric variable valve timing system is the fault state if any one of the crankshaft position, the cam position, the current voltage, and the current CAN communication signal is an invalid signal.

[0019] According to the vehicle torque control device for electric variable valve timing (EVV) failure in an embodiment of the present application, when the vehicle's electric variable valve timing system is in a faulty state, the device obtains the current engine speed and the vehicle's current required torque. Based on the current speed and / or current required torque, the device determines a target return position and the engine's optimal torque upper limit at that target return position from a pre-calibrated map, thereby controlling the vehicle's torque according to the current required torque and the optimal torque upper limit. This solves the problem of the engine stalling and battery failure when the electric variable valve timing (EVV) fails, leading to battery depletion and vehicle immobility. After the electric variable valve timing (EVV) fails, the device optimizes the inflation and torque models at the two calibrated extreme positions, adjusting the motor torque based on the maximum and minimum torque capacities at different speeds to avoid direct engine stall and meet user needs.

[0020] The third aspect of the present application provides a vehicle, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the vehicle torque control method under electric VVT failure as described in the above embodiment.

[0021] The fourth aspect of the present application provides a computer-readable storage medium, which stores computer instructions, and the computer instructions are used to enable the computer to execute the vehicle torque control method under electric VVT failure as described in the above embodiment.

[0022] The fifth aspect of the present application provides a computer program product, including a computer program, which is executed to implement the vehicle torque control method under electric VVT failure described in the above embodiment.

[0023] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which: Figure 1 A schematic diagram comparing the operating ranges of hydraulic VVT and electric VVT in related technologies; Figure 2This is a flow chart of a vehicle torque control method under electric VVT failure provided in an embodiment of the present application; Figure 3 This is a schematic diagram of an overall control flow according to one embodiment of the present application; Figure 4 A schematic diagram of torque range selection according to one embodiment of the present application; Figure 5 A schematic diagram of the torque output capacity of a two-pole position engine according to one embodiment of the present application; Figure 6 Schematic diagram of a valve lift curve according to one embodiment of the present application; Figure 7 This is an example diagram of a vehicle torque control device under electric VVT failure according to an embodiment of the present application; Figure 8 Schematic diagram of the structure of a vehicle according to an embodiment of the present application. DETAILED DESCRIPTION

[0025] The following describes in detail embodiments of the present application. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0026] The following describes, with reference to the accompanying drawings, a method, apparatus, and vehicle for controlling vehicle torque under electric variable valve timing (EVT) failure conditions according to embodiments of the present application. To address the aforementioned issue mentioned in the background art regarding the engine stalling and inability to charge the battery when the EVT fails, leading to vehicle immobility and a negative impact on user experience, the present application provides a method for controlling vehicle torque under electric variable valve timing (EVT) failure conditions. In this method, when the vehicle's electric variable valve timing system is in a faulty state, the current engine speed and the vehicle's current required torque are obtained. Based on the current speed and / or current required torque, a target return position and an optimal upper torque limit for the engine at the target return position are determined from a pre-calibrated map, thereby controlling vehicle torque based on the current required torque and the optimal upper torque limit. This solves the problem of the engine stalling and inability to charge the battery when the EVT fails, leading to vehicle immobility and a negative impact on user experience. After the EVT fails, the method optimizes the inflation model and torque model at the two calibrated extreme positions to adjust the motor torque based on the maximum and minimum torque capabilities at different speeds, avoiding direct engine stall and meeting user needs.

[0027] Specifically, before introducing the embodiments of the present application, we first introduce the vehicle torque control method in the related art. Since hybrid-powered engines focus more on improving the efficiency of the core high thermal efficiency area, the Miller cycle (or Atkinson cycle) is one of the main paths. Variable valve timing can adjust the valve timing phase to enable the engine to achieve the optimal valve timing phase, and is an important method for realizing the Miller cycle and the Atkinson cycle. Hydraulic VVT has been widely used in engines and has the advantages of mature technology, high reliability and low cost. However, it also has some shortcomings, such as: (1) Affected by the working oil conditions, the actual working temperature is generally limited to above zero degrees when used in the whole vehicle; (2) The minimum oil pressure requirement is above 1 bar (1000r / min). If the oil temperature is too high or the engine speed is too low, the oil pressure will be too low, and the VVT ​​actuator will not be able to move, and the adjustment speed and NVH will be poor; (3) Limited by the rotor structure of the phaser, the maximum adjustment range is generally within 50~60°CA; (4) Abnormal starting noise is prone to occur during cold start; (5) Due to the locking pin mechanism, frequent engine starts and stops will accelerate wear and reduce reliability.

[0028] Hydraulic VVT technology can optimize air intake and improve engine performance. The technology is very mature now, but it is limited by its structural principles and external oil conditions and cannot meet the new demands of hybrid engines. Electric VVT, with its excellent technical performance, not only meets the new functional requirements of the phaser, but also conforms to the development trend of automotive electrification. It has broad application prospects in hybrid engines. First, ultra-high compression ratio has an adverse effect on NVH. Electric VVT can adjust the phase at start-up to reduce the instantaneous cylinder pressure at start-up, thereby improving the starting characteristics. After the engine is started at low temperature, the phase needs to be adjusted as soon as possible to keep the engine combustion in the optimal state. Electric VVT is not affected by oil conditions and can meet the low-temperature phase adjustment requirements. Figure 1 As shown, compared with traditional hydraulic VVT, the use of electric VVT expands the application range of temperature and speed, and can be used at -35℃ ~ 145℃. After the ECU is initialized, maximum phase adjustment can be performed, and precise phase adjustment can be performed after the phase relationship is established.

[0029] Currently, an electric VVT typically consists of a motor, a phaser, and a controller. The controller receives signals from the camshaft and crankshaft sensors, as well as the target phase for the current operating conditions, as determined by the ECU (Electronic Control Unit). The phaser control unit independently performs closed-loop control between the actual and target phases, adjusting the drive motor speed in real time to align the actual and target phases. The initial position of the electric VVT (generally above 120° CA) is primarily used during starting, when the intake valve is closed and the cylinder volume is low. During engine start-up, the cylinder pressure is low, reducing excitation, which directly improves starting NVH (Noise, Vibration, and Harshness) performance. The maximum adjustment position of the electric VVT (generally above -30° CA) maximizes the intake and exhaust overlap angle, which improves fuel efficiency.

[0030] Furthermore, under normal working conditions, electric VVT has many advantages, but if the crankshaft position sensor, camshaft position sensor, CAN (Controller Area Network) and other faults occur, the electric VVT will not be able to obtain a valid timing signal, which will cause the electric VVT control to fail. In addition, since the electric VVT has no locking pin compared to the hydraulic VVT, the VVT ​​rotor can only be pushed by the electric VVT motor according to a certain power duty cycle until it returns to the initial mechanical stuck point position. However, the operating range of the electric VVT is as high as 150°CA (initial position and maximum adjustment position, this value is a reference value). After returning to the initial position, since the intake is in a retarded position at this time, there is not enough fresh air in the cylinder, resulting in poor engine combustion, excessive exhaust temperature or even direct flameout. At present, the commonly adopted strategy in the industry is that once the electric VVT fails, the electric VVT will return to its initial position under the action of the motor. At this time, the EMS will report a request to prohibit fuel injection to the HCU, and the engine will quickly shut down. At the same time, the vehicle will report a serious hybrid system failure. The vehicle can only rely on the power battery to maintain for a period of time. Since the engine is in the off state, it cannot charge the battery and cannot respond to the user's power needs. After running for a period of time, the power battery is exhausted and the vehicle cannot move, which directly affects the user's car experience and complaints.

[0031] Therefore, in this embodiment of the present application, based on the scenario of an electric VVT failure, an internal ECU charging model and torque model are established for the two pole positions. At 140°CA and -35°CA (reference values), lean optimization is performed according to different engine speeds and torques, calibrating the appropriate intake air volume, ignition angle, and fuel injection rate. Corrections for EGR, coolant temperature, and altitude are also included to meet combustion stability and torque model accuracy requirements. The upper and lower torque limits at different speeds are obtained and stored in the EMS control map. When an electric VVT failure occurs, the maximum and minimum torque capabilities at different speeds can be reported to the HCU according to the optimized calibration map (control parameter mapping table). The HCU can then adjust the motor torque based on the reported capabilities, ultimately meeting user needs, avoiding user complaints caused by direct engine shutdown, and improving product competitiveness.

[0032] Specifically, Figure 2 A flow chart of a vehicle torque control method under electric VVT failure provided in an embodiment of the present application.

[0033] like Figure 2 As shown, the vehicle torque control method under electric VVT failure includes the following steps: In step S201 , the current state of the vehicle's electric variable valve timing system is acquired.

[0034] Furthermore, in some embodiments, obtaining the current state of the vehicle's electric variable valve timing system includes: obtaining the crankshaft position, the cam position, the current voltage of the electric variable valve timing system and the current CAN communication signal of the electric variable valve timing system; if any one of the crankshaft position, the cam position, the current voltage and the current CAN communication signal is an invalid signal, then the current state of the electric variable valve timing system is determined to be a fault state.

[0035] Specifically, if Figure 3 As shown, first, when the system is running, the current state of the vehicle's electric variable valve timing system is obtained, and the current state of the electric variable valve timing system mainly includes the crankshaft position, the cam position, the current voltage of the electric variable valve timing system and the current CAN communication signal of the electric variable valve timing system. Then, according to the obtained current state of the electric variable valve timing system, it is determined whether the current state of the electric variable valve timing system is a fault state. If any of the crankshaft position, the cam position, the current voltage and the current CAN communication signal is an invalid signal, such as the crankshaft position sensor is short-circuited or short-circuited, or the cam position is short-circuited or short-circuited, the current CAN communication signal is faulty, the current voltage is too high or too low, etc., then the current state of the electric variable valve timing system is determined to be a fault state.

[0036] In step S202, when the current state is a fault state, the current engine speed and the current required torque of the vehicle are obtained, and based on the current speed and / or the current required torque, the target return position and the optimal torque upper limit and the optimal torque lower limit of the engine at the target return position are determined from a pre-calibrated MAP.

[0037] Furthermore, in some embodiments, before determining the target return position and the optimal torque upper limit and optimal torque lower limit of the target return position from a pre-calibrated MAP based on the current speed and / or the current required torque, it also includes: obtaining the engine's optimal ignition angle, optimal injection phase, optimal injection ratio, optimal ignition angle correction value at different coolant temperatures, minimum ignition angle and minimum load based on preset combustion stability requirements and preset torque accuracy requirements; determining the engine's optimal torque upper limit and optimal torque lower limit when the electric variable valve timing system is in the first position and the second position based on the optimal ignition angle, optimal injection phase, optimal injection ratio, optimal ignition angle correction value at different coolant temperatures, minimum ignition angle and minimum load based on different speeds, and obtaining a pre-calibrated MAP.

[0038] Further, in some embodiments, based on the current speed and the current required torque, the target return position and the optimal torque upper limit and the optimal torque lower limit of the engine at the target return position are determined from a pre-calibrated MAP, including: judging whether the current required torque is greater than the preset torque; when the current required torque is greater than the preset torque, determining the target return position as the first position, and determining the optimal torque upper limit of the engine at the target return position according to the current speed; otherwise, determining the target return position as the second position, and determining the optimal torque lower limit of the engine at the target return position according to the current speed.

[0039] Among them, the preset combustion stability requirement, the preset torque accuracy requirement, and the preset torque can all be set in the embodiment of the present application according to actual test requirements and are not specifically limited here.

[0040] Specifically, before determining that the current state of the electric variable valve timing system is a fault state and subsequently determining the target return position and the optimal torque upper limit and optimal torque lower limit of the engine at the target return position, it is necessary to determine the principles and methods of the torque range of 140°CA and -35°CA, mainly including: (1) based on the preset combustion stability requirements (such as COV (Coefficient of (1) Based on the preset combustion stability requirement (e.g. COV≤3%) and the preset torque accuracy requirement (e.g. torque≤±5%), the ignition angle is scanned at different speeds and loads to obtain the optimal ignition angle of the engine, while avoiding knock and pre-ignition; (2) Based on the preset combustion stability requirement (e.g. COV≤3%) and the preset torque accuracy requirement (e.g. torque≤±5%), the injection mode is corrected to obtain the optimal injection phase and the optimal injection ratio; (3) Based on the preset combustion stability requirement (e.g. COV≤3%) and the preset torque accuracy requirement (e.g. torque≤±5%), the optimal ignition angle correction value at different coolant temperatures is corrected, where the lower the water temperature, the greater the ignition angle correction, and the higher the altitude, the greater the ignition angle correction; (4) Based on the preset combustion stability requirement (e.g. COV≤3%) and the preset torque accuracy requirement (e.g. torque≤±5%), the minimum ignition angle and minimum load are determined to meet the requirements under this working condition if there is a sudden short-term external torque reduction request.

[0041] Furthermore, if the exhaust temperature is high (for example, above 850°C), the fuel injection amount or EGR (Exhaust Gas Recirculation) system can be appropriately increased to reduce the in-cylinder temperature and protect the engine. Based on different speeds, the electric variable valve timing system is determined according to the optimal ignition angle, optimal injection phase, optimal injection ratio, optimal ignition angle correction value at different coolant temperatures, minimum ignition angle and minimum load, and the optimal torque upper limit and optimal torque lower limit of the engine are determined when the electric variable valve timing system is in the first position and the second position, thereby ultimately obtaining a pre-calibrated MAP, such as Figure 4 As shown, based on combustion stability and torque model accuracy, taking a speed of 1500 rpm as an example, the torque output capacity at the first position (140°CA) is selected to be 50-180 Nm. Each speed should have an optimal torque output range, which is the engine capacity reported to the HCU at that time. The optimal torque range for the second position (for example, -35°CA) is similar and is not detailed here to avoid redundancy.

[0042] Furthermore, due to different speeds and loads, based on the current speed and the current required torque, the target return position and the optimal torque upper limit and the optimal torque lower limit of the engine at the target return position can be determined from the pre-calibrated MAP. In the embodiment of the present application, Figure 4 and Figure 5 As shown, the torque output characteristics of 140°CA and -35°CA are also inconsistent. It can be seen that the combustion stability and torque accuracy of the engine meet the requirements in the medium-to-high speed and high load range (160-200Nm) of -35°CA; the 140°CA meets the requirements in the medium load (50-180Nm), and the data is stored in the MAP pre-calibrated by the ECU. When the electric VVT fails, the engine's maximum and minimum torque capabilities can be directly reported according to the current working conditions.

[0043] Furthermore, when the current state of the electric variable valve timing system is in a fault state, it means that the electric VVT can no longer be controlled. Therefore, under the control of the electric VVT motor, a certain power duty cycle is applied to push the electric VVT actuator (rotor) to overcome internal friction until the initial or maximum adjustment mechanical position is reached. The two positions are achieved through clockwise and counterclockwise speed control modes (duty cycle <50% clockwise rotation, duty cycle >50% counterclockwise rotation).

[0044] Specifically, if Figure 6 As shown, according to the current design principle, when the current state of the electric variable valve timing system is in a fault state, the engine determines whether the target return position returns to the first position (i.e., the initial position) or the second position (i.e., the maximum adjustment position) based on the current speed and the HCU required torque. For example, if the current engine speed is 1500r / min, then according to the pre-calibrated MAP, it can only return to the initial position (140°CA), and the optimal torque upper limit of the engine at the target return position is determined, that is, the maximum torque reported to the HCU is 60Nm, and the maximum is 120Nm; if the engine torque required by the HCU at this time is 180Nm, the engine speed is 2000r / min, and the required torque is 2000r / min. If the torque is large, then after the electric VVT fails, it can return to the maximum adjustment position (-35°CA) to meet the HCU torque requirement. If the engine speed is still 2000r / min at this time, the optimal torque lower limit of the engine at the target return position is determined. The required torque is 160Nm. Then, according to the principle of returning to the initial position first, it directly returns to 140°CA. Since the rotation direction of the electric VVT is consistent with the rotation direction of the engine, the friction overcome when returning to the initial position is small, which is beneficial to energy saving. In addition, the time to return to the initial position will be reduced by more than 60% compared to the maximum adjustment position. Therefore, if the torque required by the HCU is not too large, the ECU will give priority to returning to the initial position.

[0045] Therefore, the above strategy shows that when an electric VVT fault is reported, the position of the two poles to return to depends entirely on the current HCU demand torque. If it is very large, it is recommended to return to the maximum adjustment position. If the demand torque is relatively small, it is prioritized to return to the initial position. At the same time, according to the pre-calibrated MAP, the optimal upper and lower torque limits of the engine at the target return position are reported. In this way, the HCU can increase or decrease the motor torque accordingly based on the reporting capacity to meet the user's power requirements.

[0046] Furthermore, the electric VVT has variable valve timing, and the two pole positions of the intake VVT ​​are the initial position and the maximum adjustment angle position. Within this range, it can move back and forth to ensure the optimal combustion stability, torque accuracy, fuel consumption and other indicators under different VVT angles.

[0047] For example, after the electric VVT fails and returns to the initial position, the engine is affected by combustion stability, torque accuracy, etc., and the maximum output torque is only 180Nm. If the HCU's required torque for the engine is greater than 180Nm, or the current vehicle's required torque is greater than the engine's reporting capacity and the motor (battery) reporting capacity, then the system will prompt the user to enter the torque limitation mode to avoid the user's aggressive driving or reducing the torque demand. According to the calibration data of the application embodiment, even if it returns to the initial position, the engine's torque capacity can still cover more than 80% of the user's operating conditions. Therefore, compared with the current industry-wide crude method of directly shutting down the engine, both the user's power demand and the engine's output torque for battery charging are more advantageous.

[0048] In step S203 , the vehicle is torque controlled according to the current required torque and the optimal torque upper limit of the engine at the target return position.

[0049] Further, in some embodiments, the vehicle is torque controlled based on the current required torque and the optimal torque upper limit of the engine at the target return position, including: calculating the difference between the current required torque and the optimal torque upper limit of the engine at the target return position; if the difference is greater than the vehicle's motor output torque upper limit, the vehicle is torque controlled based on the motor output torque upper limit and the optimal torque upper limit of the engine at the target return position, otherwise, while controlling the engine to output torque based on the optimal torque upper limit of the engine at the target return position, the vehicle's motor is controlled to output torque based on the difference.

[0050] Furthermore, in some embodiments, after determining that the difference is greater than the upper limit of the motor output torque of the vehicle, the method further includes: generating torque limit reminder information; and controlling the vehicle to perform torque limit reminder based on the torque limit reminder information.

[0051] Specifically, if Figure 3As shown, if the difference between the current required torque and the optimal torque upper limit of the engine at the target return position is greater than the vehicle's motor output torque upper limit, the vehicle is torque controlled based on the motor output torque upper limit and the optimal torque upper limit of the engine at the target return position; otherwise, while the engine is controlled to output torque based on the optimal torque upper limit of the engine at the target return position, the vehicle's motor is controlled to output torque based on the difference, and torque limit reminder information is generated to control the vehicle to perform a torque limit reminder based on the torque limit reminder information.

[0052] In summary, based on the discussion of the above specific embodiments, this application can achieve the following beneficial effects: (1) The HCU processing mode in the event of electric VVT failure can still meet user needs by showing the torque output under different working conditions through the VVT ​​pole positions, avoiding user complaints caused by the rough processing method of direct engine shutdown; (2) In the case of electric VVT failure, the principle of electric VVT returning to the two-pole position is used to re-establish the charging model and torque model under the electric VVT failure mode, and achieve engine combustion stability and torque model accuracy through ignition angle, intake volume, fuel injection, etc. (3) The reporting principle and method of the maximum and minimum torque capabilities at the two-pole positions. According to the HCU's required torque for the engine, the motor torque is increased or decreased to achieve the same total required torque of the vehicle; (4) When the vehicle's required torque is greater than the engine and motor capabilities, a torque limit mode is used to alert the user.

[0053] According to the vehicle torque control method for electric variable valve timing (EVV) failure in an embodiment of the present application, when the vehicle's electric variable valve timing system is in a faulty state, the current engine speed and the vehicle's current required torque are obtained. Based on the current speed and / or current required torque, a target return position and the engine's optimal torque upper limit at the target return position are determined from a pre-calibrated map, thereby controlling the vehicle's torque according to the current required torque and the optimal torque upper limit. This method solves the problem of the engine stalling and battery failure when the electric variable valve timing (EVV) fails, leading to battery depletion and vehicle immobility. After the electric variable valve timing (EVV) fails, the method optimizes the inflation and torque models at the two calibrated extreme positions, adjusting the motor torque based on the maximum and minimum torque capabilities at different speeds to avoid direct engine stall and meet user needs.

[0054] Next, the vehicle torque control device under electric VVT failure proposed in an embodiment of the present application will be described with reference to the accompanying drawings.

[0055] Figure 7 It is a block diagram of the vehicle torque control device under electric VVT failure according to an embodiment of the present application.

[0056] like Figure 7 As shown, the vehicle torque control device 10 under electric VVT failure includes: an acquisition module 100, a determination module 200 and a control module 300.

[0057] The acquisition module 100 is used to acquire the current state of the vehicle's electric variable valve timing system; a determination module 200 for obtaining a current engine speed and a current required torque of the vehicle when the current state is a fault state, and determining a target return position and an optimal upper torque limit and an optimal lower torque limit of the engine at the target return position from a pre-calibrated MAP based on the current engine speed and / or the current required torque; The control module 300 is configured to perform torque control on the vehicle according to the current required torque and the upper limit of the optimal torque of the engine at the target return position.

[0058] Furthermore, in some embodiments, before determining the target return position and the optimal upper torque limit and the optimal lower torque limit of the target return position from a pre-calibrated MAP based on the current speed and / or the current required torque, the determination module 200 further includes: a first acquisition unit, configured to acquire an optimal ignition angle, an optimal injection phase, an optimal injection ratio, an optimal ignition angle correction value at different coolant temperatures, a minimum ignition angle, and a minimum load of the engine based on a preset combustion stability requirement and a preset torque accuracy requirement; The first determination unit is configured to determine, based on different speeds, an optimal ignition angle, an optimal injection phase, an optimal injection ratio, an optimal ignition angle correction value at different coolant temperatures, a minimum ignition angle, and a minimum load, an optimal torque upper limit and an optimal torque lower limit of the engine when the electric variable valve timing system is in a first position and a second position, thereby obtaining a pre-calibrated MAP.

[0059] Furthermore, in some embodiments, the determination module 200 includes: A judgment unit, used to judge whether the current required torque is greater than the preset torque; The second determination unit is used to determine the target return position as the first position when the current required torque is greater than the preset torque, and determine the optimal torque upper limit of the engine at the target return position based on the current speed; otherwise, determine the target return position as the second position, and determine the optimal torque lower limit of the engine at the target return position based on the current speed.

[0060] Furthermore, in some embodiments, the control module 300 includes: a calculation unit, configured to calculate a difference between a current required torque and an upper limit of an optimal torque of the engine at a target return position; A control unit is used to control the torque of the vehicle based on the upper limit of the motor output torque and the optimal torque upper limit of the engine at the target return position if the difference is greater than the upper limit of the motor output torque of the vehicle; otherwise, while controlling the engine to output torque based on the optimal torque upper limit of the engine at the target return position, the motor of the vehicle is controlled to output torque based on the difference.

[0061] Furthermore, in some embodiments, after determining that the difference is greater than an upper limit of the motor output torque of the vehicle, the control unit further includes: A generating subunit, used for generating torque limit reminder information; The control subunit is used to control the vehicle to perform torque limit reminder based on the torque limit reminder information.

[0062] Furthermore, in some embodiments, the acquisition module 100 includes: a second acquisition unit, configured to acquire a crankshaft position, a cam position, a current voltage of an electric variable valve timing system, and a current CAN communication signal of the electric variable valve timing system; The determination unit is configured to determine that the current state of the electric variable valve timing system is a fault state if any one of the crankshaft position, the cam position, the current voltage, and the current CAN communication signal is an invalid signal.

[0063] According to the vehicle torque control device for electric variable valve timing (EVV) failure in an embodiment of the present application, when the vehicle's electric variable valve timing system is in a faulty state, the device obtains the current engine speed and the vehicle's current required torque. Based on the current speed and / or current required torque, the device determines a target return position and the engine's optimal torque upper limit at that target return position from a pre-calibrated map, thereby controlling the vehicle's torque according to the current required torque and the optimal torque upper limit. This solves the problem of the engine stalling and battery failure when the electric variable valve timing (EVV) fails, leading to battery depletion and vehicle immobility. After the electric variable valve timing (EVV) fails, the device optimizes the inflation and torque models at the two calibrated extreme positions, adjusting the motor torque based on the maximum and minimum torque capacities at different speeds to avoid direct engine stall and meet user needs.

[0064] Figure 8 A schematic diagram of the structure of a vehicle provided in an embodiment of the present application. The vehicle may include: A memory 801 , a processor 802 , and a computer program stored in the memory 801 and executable on the processor 802 .

[0065] When the processor 802 executes the program, the vehicle torque control method under electric VVT failure provided in the above embodiment is implemented.

[0066] Furthermore, the vehicle further comprises: The communication interface 803 is used for communication between the memory 801 and the processor 802 .

[0067] The memory 801 is used to store computer programs that can be run on the processor 802.

[0068] The memory 801 may include a high-speed RAM memory, and may also include a non-volatile memory (non-volatile memory), such as at least one disk memory.

[0069] If the memory 801, processor 802, and communication interface 803 are implemented independently, the communication interface 803, memory 801, and processor 802 can be connected to each other via a bus and communicate with each other. The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus. Buses can be divided into address buses, data buses, control buses, etc. For ease of representation, 8 Figure 8 Only one thick line is used in the diagram, but this does not mean that there is only one bus or one type of bus.

[0070] Optionally, in a specific implementation, if the memory 801, the processor 802 and the communication interface 803 are integrated on a chip, the memory 801, the processor 802 and the communication interface 803 can communicate with each other through an internal interface.

[0071] The processor 802 may be a central processing unit (CPU), an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of the present application.

[0072] This embodiment also provides a computer-readable storage medium having a computer program stored thereon. When the program is executed by a processor, the above-mentioned vehicle torque control method under electric VVT failure is implemented.

[0073] This embodiment also provides a computer program product, including a computer program, which is executed to implement the vehicle torque control method under electric VVT failure of the above embodiment.

[0074] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or N embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0075] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Thus, a feature specified as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of this application, "N" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0076] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, fragment or portion of code comprising one or more executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may be performed out of the order shown or discussed, including performing functions in a substantially simultaneous manner or in reverse order depending on the functions involved, which should be understood by those skilled in the art to which the embodiments of the present application belong.

[0077] The logic and / or steps represented in a flowchart or otherwise described herein, for example, can be considered a sequenced list of executable instructions for implementing the logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (e.g., a computer-based system, a system including a processor, or other system that can fetch and execute instructions from an instruction execution system, apparatus, or device). For purposes of this specification, a "computer-readable medium" is any device that can contain, store, communicate, propagate, or transport a program for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (not exhaustive) of computer-readable media include: an electrical connection with one or more wires (electronic devices), a portable computer disk cartridge (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and programmable read-only memory (EPROM or flash memory), fiber optic devices, and a portable compact disc read-only memory (CDROM). Furthermore, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium and then editing, interpreting or otherwise processing it in a suitable manner if necessary, and then storing it in a computer memory.

[0078] It should be understood that various parts of this application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiment, the N steps or methods can be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented using hardware, as in another embodiment, any one of the following technologies known in the art or a combination thereof can be used: a discrete logic circuit having logic gate circuits for implementing logical functions on data signals, an application-specific integrated circuit having suitable combinational logic gate circuits, a programmable gate array (PGA), a field-programmable gate array (FPGA), etc.

[0079] Those skilled in the art will appreciate that all or part of the steps in the method for implementing the above-mentioned embodiment can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable storage medium. When the program is executed, it includes one or a combination of the steps of the method embodiment.

[0080] In addition, the functional units in the various embodiments of the present application may be integrated into a processing module, or each unit may exist physically separately, or two or more units may be integrated into a module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0081] The storage medium mentioned above may be a read-only memory, a magnetic disk, or an optical disk, etc. Although the embodiments of the present application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present application. Persons skilled in the art may make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present application.

Claims

1. A vehicle torque control method under electric VVT failure, characterized in that: The following steps are involved: Get the current status of the vehicle's electric variable valve timing system; When the current state is a fault state, obtaining a current engine speed and a current required torque of the vehicle, and determining a target return position and an optimal upper torque limit and an optimal lower torque limit of the engine at the target return position from a pre-calibrated map based on the current engine speed and / or the current required torque; The vehicle is torque controlled according to the current required torque and an optimal torque upper limit of the engine at the target return position.

2. The method according to claim 1, characterized in that Before determining the target return position and the optimal upper torque limit and the optimal lower torque limit of the target return position from a pre-calibrated MAP based on the current speed and / or the current required torque, the method further includes: Based on the preset combustion stability requirements and the preset torque accuracy requirements, the engine's optimal ignition angle, optimal injection phase, optimal injection ratio, optimal ignition angle correction value at different coolant temperatures, minimum ignition angle, and minimum load are obtained; Based on different speeds, the optimal ignition angle, the optimal injection phase, the optimal injection ratio, the optimal ignition angle correction value at different coolant temperatures, the minimum ignition angle, and the minimum load, the electric variable valve timing system is determined to determine the optimal torque upper limit and the optimal torque lower limit of the engine when in the first position and the second position, thereby obtaining the pre-calibrated MAP.

3. The method according to claim 1, characterized in that The determining, based on the current speed and / or the current required torque, from a pre-calibrated MAP, of a target return position and an optimal upper torque limit and an optimal lower torque limit of the engine at the target return position, includes: Determining whether the current required torque is greater than a preset torque; When the current required torque is greater than the preset torque, the target return position is determined to be the first position, and the optimal torque upper limit of the engine at the target return position is determined based on the current speed; otherwise, the target return position is determined to be the second position, and the optimal torque lower limit of the engine at the target return position is determined based on the current speed.

4. The method according to claim 1, wherein The performing torque control on the vehicle according to the current required torque and the optimal torque upper limit of the engine at the target return position includes: Calculating a difference between the current required torque and an upper limit of an optimal torque of the engine at the target return position; If the difference is greater than the upper limit of the motor output torque of the vehicle, the vehicle is torque controlled based on the upper limit of the motor output torque and the optimal torque upper limit of the engine at the target return position; otherwise, while the engine is controlled based on the optimal torque upper limit control of the engine at the target return position to output torque, the motor of the vehicle is controlled to output torque based on the difference.

5. The method according to claim 4, characterized in that After determining that the difference is greater than the upper limit of the motor output torque of the vehicle, the method further includes: Generate torque limit reminder information; Based on the torque limit reminder information, the vehicle is controlled to perform a torque limit reminder.

6. The method according to claim 1, characterized in that The obtaining of the current state of the vehicle's electric variable valve timing system includes: Acquiring a crankshaft position, a cam position, a current voltage of the electric variable valve timing system, and a current CAN communication signal of the electric variable valve timing system; If any one of the crankshaft position, the cam position, the current voltage, and the current CAN communication signal is an invalid signal, it is determined that the current state of the electric variable valve timing system is the fault state.

7. A vehicle torque control device under electric VVT failure, characterized in that: include: An acquisition module, used to acquire a current state of an electric variable valve timing system of a vehicle; a determination module configured to obtain, when the current state is a fault state, a current engine speed and a current required torque of the vehicle, and determine, based on the current engine speed and / or the current required torque, a target return position and an optimal upper torque limit and an optimal lower torque limit of the engine at the target return position from a pre-calibrated map; A control module is configured to perform torque control on the vehicle according to the current required torque and an upper limit of an optimal torque of the engine at the target return position.

8. The device according to claim 7, characterized in that Before determining the target return position and the optimal upper torque limit and the optimal lower torque limit of the target return position from a pre-calibrated MAP based on the current speed and / or the current required torque, the determining module further includes: an acquisition unit, configured to acquire an optimal ignition angle, an optimal fuel injection phase, an optimal injection ratio, an optimal ignition angle correction value at different coolant temperatures, a minimum ignition angle, and a minimum load of the engine based on a preset combustion stability requirement and a preset torque accuracy requirement; a determining unit, configured to determine, based on different speeds, the optimal ignition angle, the optimal injection phase, the optimal injection ratio, the optimal ignition angle correction value at different coolant temperatures, the minimum ignition angle, and the minimum load, an optimal torque upper limit and an optimal torque lower limit of the engine when the electrically variable valve timing system is in a first position and a second position, thereby obtaining the pre-calibrated MAP.

9. A vehicle, characterized in that: include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the vehicle torque control method under electric VVT failure as described in any one of claims 1 to 6.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: The program is executed by a processor to implement the vehicle torque control method under electric VVT failure as described in any one of claims 1 to 6.

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