A range extender starting control method and vehicle

Abstract

The application provides a range extender starting control method and a vehicle, and relates to the technical field of vehicle control. The method comprises the following steps: if a preset starting condition of a range extender is met, a generator in the range extender is controlled to drag an engine in reverse; after the reverse dragging ends, the generator is controlled to enter a torque control mode according to current environmental parameters and an actual torque of the generator, so that the generator drags the engine in forward direction; after the generator enters the torque control mode, a first rotating speed of the engine is obtained; if the first rotating speed of the engine reaches a preset rotating speed, the generator is controlled to switch from the torque control mode to a rotating speed control mode; after the generator enters the rotating speed control mode, a second rotating speed of the engine is obtained; if the second rotating speed of the engine reaches an ignition target rotating speed, the engine is controlled to inject fuel and ignite; and after the engine ignites successfully, the generator is controlled to switch to a power generation mode. The application can improve the NVH quality and reliability of the range extender starting in different scenarios.

Description

Technical Field

[0001] This application relates to the field of vehicle control technology, and more specifically, to a range extender start-up control method and a vehicle. Background Technology

[0002] Range-extended electric vehicles (REEVs) are vehicles that are driven by an electric motor, with the internal combustion engine serving only as an auxiliary power unit for generating electricity. A range extender typically consists of an engine and a generator. When the battery is low on power, the engine starts and drives the generator to produce electricity, either to power the drive motor or to charge the battery, thereby extending the vehicle's driving range.

[0003] The start-up process of a range extender requires the generator to drive the engine to the target speed before fuel injection and ignition, and then the generator to switch to generator mode. This process involves torque-speed coordination control between the generator and the engine, which is a key technical aspect of the overall vehicle control of a range-extended electric vehicle. Because the start-up frequency of range extenders is much higher than that of traditional gasoline vehicles, and the start-up conditions are complex and diverse, higher requirements are placed on the smoothness, robustness, and adaptability of the start-up control.

[0004] In existing technologies, range extenders often employ fixed-parameter torque or speed control strategies for startup, which cannot dynamically adjust according to environmental changes and hardware differences. This results in poor consistency in noise, vibration, and harshness (NVH) during the startup process under different operating conditions. Furthermore, because ignition judgment relies on speed signals and there is a lack of effective utilization of generator feedback torque, problems such as insufficient ignition success rate, severe speed overshoot, and runaway risk exist. Moreover, when control parameters are transferred to different vehicle models, a large amount of manual calibration is required, resulting in low engineering efficiency. Summary of the Invention

[0005] This application provides a range extender start-up control method and vehicle, which can improve the NVH quality and reliability of the range extender during start-up in different scenarios.

[0006] In a first aspect, embodiments of this application provide a range extender start-up control method, the method comprising: If the preset starting conditions of the range extender are met, the generator in the range extender is controlled to reverse and drive the engine. After the reverse drag ends, based on the current environmental parameters and the actual torque of the generator in the range extender, the generator is controlled to enter the torque control mode, so that the generator drags the engine in the forward direction; After the generator enters the torque control mode, the first speed of the engine is obtained; If the first speed of the engine reaches the preset speed, the generator is controlled to switch from the torque control mode to the speed control mode; After the generator enters the speed control mode, the second speed of the engine is obtained; If the second speed of the engine reaches the target ignition speed, control the engine to inject fuel and ignite. After the engine is successfully ignited, the generator is switched to power generation mode.

[0007] Optionally, controlling the generator to enter torque control mode based on the current environmental parameters and the actual torque of the generator in the range extender, so that the generator drives the engine in the forward direction, includes: Calculate the feedforward torque of the engine in the range extender based on the current environmental parameters; The target torque is calculated based on the feedforward torque, the actual torque of the generator, and the preset torque ramp-up gradient. Based on the target torque, the generator is controlled to enter torque control mode, so that the generator drives the engine in the forward direction.

[0008] Optionally, the current environmental parameters include: multiple environmental parameters; calculating the feedforward torque of the engine in the range extender based on the current environmental parameters includes: For each of the environmental parameters, a preset torque relationship table and a preset weight relationship table are queried to obtain the corresponding base torque and weight coefficient; wherein, the preset torque relationship table stores the mapping relationship between each environmental parameter and the base torque, and the preset weight relationship table stores the mapping relationship between each environmental parameter and the weight coefficient. The feedforward torque is calculated using the friction torque evaluation model of the engine, based on the weight parameters corresponding to the various environmental parameters and the corresponding base torque.

[0009] Optionally, the method further includes: Obtain the actual speed curve of the engine during the forward drag process; Based on the actual speed curve and the preset ideal speed curve, determine the speed deviation for this start-up; The preset weighted relationship table is corrected based on the speed deviation.

[0010] Optionally, switching the generator from the torque control mode to the speed control mode includes: Obtain the preset first target control speed; Based on the first target control speed, the generator is controlled to switch from the torque control mode to the speed control mode in the first speed control phase; After the generator enters the first speed control stage, if the engine speed reaches the first target control speed, the ignition target speed is taken as the second target control speed. Based on the second target control speed, the generator is controlled to enter the second speed control stage from the first speed control stage.

[0011] Optionally, obtaining the preset first target control speed includes: Obtain the first target control speed that is stored in advance. The first target control speed is a speed calculated based on the maximum speed of the engine, the preset base speed and the ignition target speed during the last start-up process. The preset base speed is any speed value that is greater than the preset speed and less than the ignition target speed.

[0012] Optionally, the method further includes: If the duration of the torque control mode exceeds a preset duration and the first speed does not reach the preset speed, or if the engine speed decreases by more than a preset decrease, the generator is controlled to switch from the torque control mode to the speed control mode.

[0013] Optionally, controlling the engine fuel injection and ignition includes: Based on a preset engine idle speed, the engine is controlled to enter an idle speed control mode, and in the idle speed control mode, the engine is controlled to perform fuel injection and ignition, wherein the preset engine idle speed is greater than the target ignition speed.

[0014] Optionally, before controlling the generator to switch to power generation mode after the engine has successfully ignited, the method further includes: After controlling the engine's fuel injection and ignition, the feedback torque of the generator is continuously monitored; If the feedback torque is less than a preset threshold, the engine is determined to have ignited successfully.

[0015] Secondly, embodiments of this application also provide a range-extended electric vehicle, the range-extended electric vehicle comprising: a vehicle body, a vehicle controller, and a range extender, the range extender comprising: a generator, an engine, a generator controller, and an engine management system; the vehicle controller and the range extender are both disposed on the vehicle body, the generator controller is connected to the generator, the engine management system is connected to the engine, and the vehicle controller is connected to both the generator controller and the engine management system; the vehicle controller is used to execute the range extender start-up control method as described in any one of the first aspects.

[0016] This application provides a range extender start-up control method and vehicle. During the range extender start-up process, the method first determines whether the preset start-up conditions of the range extender are met. When the conditions are met, the generator in the range extender is controlled to reverse-drive the engine. After the reverse-drive is completed, based on the current environmental parameters and the actual torque of the generator, the generator is controlled to enter torque control mode, causing the generator to drive the engine in the forward direction according to torque control mode, thereby increasing the engine speed. During operation in torque control mode, the generator acquires the engine's first speed in real time and compares it with a preset speed. When the first speed reaches the preset speed, the generator is controlled to switch from torque control mode to speed control mode. After entering speed control mode, the generator acquires the engine's second speed in real time and compares it with the ignition target speed. When the second speed reaches the ignition target speed, the engine is controlled to inject fuel and ignite. After successful engine ignition, the generator is controlled to switch from speed control mode to generator mode, thereby realizing the start-up control of the range extender. Through the above control methods, the generator can output torque that matches the current operating condition under different environmental conditions, ensuring the stability and consistency of the starting process under different environmental conditions; the speed control mode stabilizes the engine at the target ignition speed before fuel injection and ignition, improving the ignition success rate; overall, it improves the NVH quality and reliability of the range extender in different scenarios, enabling the range extender to adapt to different driving scenarios and improving the driving experience of range-extended electric vehicles. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A flowchart illustrating a range extender start-up control method provided in an embodiment of this application; Figure 2 A schematic diagram of the forward-driving engine in a range extender start-up control method provided in an embodiment of this application; Figure 3 A schematic flowchart illustrating the calculation of feedforward torque in a range extender start-up control method provided in this application embodiment; Figure 4 A flowchart illustrating the modification of a preset weight relationship table in a range extender start-up control method provided in this application embodiment; Figure 5 A flowchart illustrating the switching of speed control mode in a range extender start-up control method provided in this application embodiment; Figure 6 This is a flowchart illustrating the process of determining successful engine ignition in a range extender start-up control method provided in an embodiment of this application. Figure 7 An interactive block diagram of a range extender start-up control method provided in an embodiment of this application; Figure 8 A schematic diagram of a range extender start-up control device provided in an embodiment of this application; Figure 9 This is a schematic diagram of a vehicle controller provided in an embodiment of this application. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0020] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0021] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0022] Before providing a detailed explanation of this application, let's first introduce its application scenarios.

[0023] When a vehicle enters a high-power-demand scenario such as driving on a highway or continuously climbing an incline, the battery charge drops rapidly. In such cases, the range extender needs to be activated to provide continuous power replenishment. Furthermore, in low-temperature winter environments or high-altitude, low-pressure areas, the starting conditions for the range extender are more demanding. Increased engine resistance when cold and greater difficulty in ignition place higher requirements on the adaptability and robustness of the starting control. Under these varied real-world driving conditions, the environmental adaptability of the range extender's starting process directly impacts the overall driving quality and reliability of the vehicle.

[0024] Based on this, this application provides a range extender start-up control method and vehicle. During the range extender start-up process, the method first determines whether the preset start-up conditions of the range extender are met. When the conditions are met, the method controls the generator in the range extender to reverse-drive the engine. After the reverse-drive is completed, based on the current environmental parameters and the actual torque of the generator, the method controls the generator to enter torque control mode, causing the generator to drive the engine in the forward direction according to the torque control mode, thereby increasing the engine speed. During operation in torque control mode, the generator acquires the engine's first speed in real time and compares it with a preset speed. When the first speed reaches the preset speed, the method controls the generator to switch from torque control mode to forward-drive the engine, thereby increasing the engine speed. The torque control mode switches to the speed control mode. After the generator enters the speed control mode, it acquires the engine's second speed in real time and compares it with the ignition target speed. When the second speed reaches the ignition target speed, it controls the engine to inject fuel and ignite. After the engine ignites successfully, it controls the generator to switch from the speed control mode to the power generation mode, thereby realizing the start-up control of the range extender. This ensures the stability and consistency of the start-up process under different environmental conditions, improves the ignition success rate, and improves the overall NVH quality and reliability of the range extender in different scenarios. This enables the range extender to adapt to different driving scenarios and improves the driving experience of range-extended electric vehicles.

[0025] The range extender start-up control method provided in this application embodiment can be executed by a vehicle domain controller (VDC) with data processing and communication capabilities. The vehicle domain controller includes, but is not limited to, a vehicle domain controller, a domain controller, or a central computing platform. Its form can be an independent single controller or a vehicle-level processing system composed of multiple controllers working together. This application embodiment does not specifically limit this.

[0026] The following explanation, in conjunction with the accompanying drawings, uses several embodiments to illustrate the concepts. Figure 1 This is a flowchart illustrating a range extender start-up control method provided in an embodiment of this application, as shown below. Figure 1 As shown, the range extender start-up control method includes: S101, if the preset starting conditions of the range extender are met, control the generator in the range extender to drive the engine in reverse.

[0027] First, the vehicle controller monitors whether the preset starting conditions of the range extender are met. Optionally, the preset starting conditions may include the battery charge being lower than a preset charge threshold, or the vehicle's power demand exceeding the battery's discharge capacity. When the vehicle controller determines that the preset starting conditions are met, it sends a torque control mode request command to the generator controller (GCU) and simultaneously sends the target torque value. Upon receiving the command, the generator controller controls the generator to operate in torque control mode. In torque control mode, the generator outputs positive torque according to the target torque sent by the vehicle controller, driving the engine to rotate and causing the engine speed to rise from zero.

[0028] Before the generator enters torque control mode, the generator in the range extender is first controlled to reverse-drive the engine to eliminate transmission gear backlash. Specifically, the vehicle controller obtains the current engine coolant temperature and queries the preset drag torque table and drag duration table according to the engine coolant temperature to obtain the reverse drag torque and reverse drag duration corresponding to the current coolant temperature.

[0029] The drag torque table stores the correspondence between the coolant temperature of each engine and the reverse drag torque, as shown in Table 1: Table 1. Torque Table

[0030] The drag duration table stores the correspondence between the coolant temperature of each engine and the reverse drag duration, as shown in Table 2: Table 2 Drag Duration Table

[0031] Taking an engine coolant temperature of 20℃ as an example, the vehicle controller can find the reverse drag torque as -32Nm from Table 1 above, and the reverse drag duration as 130ms from Table 2 above. The vehicle controller sends the reverse drag torque and reverse drag duration obtained from the tables to the generator controller. The generator controller controls the generator to reverse drag the engine with the reverse drag torque and continue the reverse drag for the specified duration, so that the tooth surfaces of the transmission gears are tightly engaged during the reverse micro-movement, eliminating the clearance between the gears. After the reverse drag ends, the generator stops outputting torque.

[0032] S102, after the reverse drag ends, controls the generator to enter torque control mode based on the current environmental parameters and the actual torque of the generator in the range extender, so that the generator drags the engine in the forward direction.

[0033] After the reverse drag ends, the generator is controlled to enter torque control mode.

[0034] Specifically, the vehicle controller acquires current environmental parameters, including but not limited to one or more of the following: ambient temperature, engine downtime, engine coolant temperature, and atmospheric pressure. These environmental parameters directly affect the engine's internal friction resistance, pumping resistance, and physical properties such as lubricating oil viscosity during startup. The vehicle controller also receives real-time feedback from the generator controller regarding the generator's actual torque, which reflects the generator's true torque output within the current control cycle. Based on the aforementioned environmental parameters and the generator's actual torque, the vehicle controller determines the target torque required by the generator for the current control cycle and sends this target torque to the generator controller. The generator controller then controls the generator to output the corresponding positive torque according to the target torque, ensuring the generator continuously drives the engine to accelerate with appropriate torque.

[0035] S103 obtains the engine's first speed after the generator enters torque control mode.

[0036] After the generator enters torque control mode and begins to drive the engine in the forward direction, the vehicle controller continuously acquires the current engine speed information, which is recorded as the first speed.

[0037] Specifically, the generator controller integrates a speed sensor that measures the generator rotor's rotational speed in real time and reports the result as the generator's actual speed to the vehicle controller. Upon receiving the generator's actual speed from the generator controller, the vehicle controller converts the generator's actual speed into the engine's speed based on the mechanical transmission ratio between the generator and the engine, and uses the converted speed value as the engine's current initial speed. Because the generator and engine are rigidly connected via gears or couplings, their speeds during startup are in a fixed proportional relationship. Therefore, the engine speed calculated from the generator speed accurately reflects the engine's current rotational speed.

[0038] The vehicle controller periodically performs the first speed acquisition operation according to a preset control cycle. Optionally, the control cycle can be set according to actual application requirements, such as 10 milliseconds, 20 milliseconds, or 50 milliseconds. By continuously acquiring the engine's first speed in each control cycle, the vehicle controller can track the engine speed change trend in real time and respond promptly to speed changes to make corresponding control decisions.

[0039] S104, if the engine's first speed reaches the preset speed, control the generator to switch from torque control mode to speed control mode.

[0040] Specifically, in each control cycle, the vehicle controller compares the acquired first engine speed with a preset speed. The preset speed is a pre-defined speed threshold used to determine whether the engine has completed the torque control drag phase and can enter the speed control phase. Optionally, the preset speed can be calibrated according to the engine's mechanical characteristics and starting performance requirements, for example, set to 750 rpm. When the vehicle controller determines that the first speed has reached or exceeded the preset speed, the vehicle controller considers that the engine has met the conditions to enter the speed control phase. At this time, it sends a mode switching command to the generator controller, instructing the generator controller to switch the generator's control mode from torque control mode to speed control mode.

[0041] In speed control mode, the generator controller receives the target speed command from the vehicle controller and uses the target speed as the control target. Through its internal speed closed-loop control algorithm, it automatically adjusts the generator's output torque to ensure the generator's actual speed follows the target speed. Since the generator and engine are rigidly connected, the generator speed is the same as the engine speed; therefore, controlling the generator speed allows for control of the engine speed.

[0042] The generator controller internally operates a closed-loop speed control algorithm. This algorithm takes the deviation between the target speed and the actual speed as input, and after PID (Proportional-Integral-Derivative) adjustment, outputs a corresponding torque control quantity, allowing the generator's output torque to dynamically adjust according to the speed deviation. When the actual speed is lower than the target speed, the generator outputs positive torque to accelerate; when the actual speed approaches or reaches the target speed, the generator automatically reduces the output torque to maintain a stable speed. Through this method, the generator's control objective changes from outputting a preset amount of torque to maintaining a preset amount of speed, thus altering the control logic.

[0043] Furthermore, during the process of the generator switching from torque control mode to speed control mode, the vehicle controller continuously monitors the engine speed changes. If the generator control mode has been switched to speed control mode, but the engine speed experiences an abnormal drop or fluctuation, the vehicle controller can adaptively adjust the target speed according to the actual operating conditions to ensure the stability of the speed control process.

[0044] S105: After the generator enters the speed control mode, the second engine speed is obtained.

[0045] After the generator successfully switches to speed control mode, the vehicle controller continues to acquire the current engine speed information according to the preset control cycle, which is recorded as the second speed.

[0046] Similar to the method used to obtain the first engine speed, the vehicle controller obtains the actual speed of the generator through the generator controller during the speed control phase, and converts the actual speed into the engine speed based on the mechanical transmission ratio between the generator and the engine. Specifically, the speed sensor inside the generator controller continuously measures the rotational speed of the generator rotor and reports the measurement result as the actual speed of the generator to the vehicle controller in real time. After receiving the actual speed, the vehicle controller converts it into the engine speed and uses the converted speed value as the second engine speed at the current moment.

[0047] The vehicle controller continuously performs the second speed acquisition operation described above in each control cycle. The control cycle can be consistent with the control cycle in step S102. By continuously acquiring the engine's second speed in each control cycle, the vehicle controller can track the engine speed changes in the speed control mode in real time and respond to speed changes in a timely manner to make corresponding control decisions.

[0048] S106: If the engine's second speed reaches the ignition target speed, control the engine to inject fuel and ignite.

[0049] Specifically, in each control cycle, the vehicle controller compares the acquired second engine speed with the ignition target speed. The ignition target speed is a preset speed threshold used to determine whether the engine has reached the speed condition for safe ignition. Optionally, the ignition target speed can be calibrated according to the engine's mechanical characteristics and ignition performance requirements, for example, set to 1100 rpm. When the vehicle controller determines that the second speed has reached or exceeded the ignition target speed, and the duration reaches a preset stable duration, the vehicle controller considers the engine to be ready for ignition.

[0050] After determining that the second engine speed has reached the target ignition speed, the vehicle controller sends a fuel injection ignition permission command to the engine management system (ECU). In one possible implementation, upon receiving the fuel injection ignition permission command, the ECU controls the engine's injectors to begin injecting fuel, and simultaneously controls the ignition system to ignite according to the preset ignition timing. After fuel injection and ignition, the air-fuel mixture inside the engine begins to burn. The expansion pressure generated by combustion pushes the piston, causing the engine to transition from a passive rotation state dependent on the generator to an active operation state that autonomously outputs torque.

[0051] During engine fuel injection and ignition, the vehicle controller continues to keep the generator in speed control mode, ensuring that the generator continuously adjusts its speed to match the target ignition speed. Since the engine's torque output is unstable at the moment of ignition, maintaining generator speed control provides stable speed support for the engine during the initial torque fluctuations of combustion, preventing speed drops caused by insufficient engine torque.

[0052] S107 controls the generator to switch to power generation mode after the engine is successfully ignited.

[0053] Specifically, after successful engine ignition, the engine can maintain operation using the torque generated by its own combustion, no longer requiring the generator to provide positive driving torque. At this point, the vehicle controller sends a power generation mode request command to the generator controller, which includes the target speed for the power generation mode. Upon receiving the power generation mode request command, the generator controller switches the generator from speed control mode to power generation mode. In power generation mode, the generator's control objective changes from maintaining engine speed to operating with the generator load following the engine. The generator no longer outputs positive torque to drive the engine; instead, it is driven to rotate by the engine, converting the engine's mechanical energy into electrical energy.

[0054] In one possible implementation, in power generation mode, the power control algorithm inside the generator controller adjusts the generator's excitation current based on the power generation demand sent by the vehicle controller. This allows the generator to produce electrical energy corresponding to the target power generation as it rotates alongside the engine. The electrical energy is then rectified, regulated, and output to the battery. At this time, the vehicle controller controls the generator's load on the engine by adjusting the power generation, thus indirectly regulating the engine's operating state. Simultaneously with the generator switching to power generation mode, the vehicle controller also sends a torque control mode request command to the engine management system, causing the system to adjust the engine's control mode to torque control. In torque control mode, the engine management system controls the engine's fuel injection and air intake based on the target torque value sent by the vehicle controller, ensuring the engine outputs torque matching the target power generation. This achieves power balance between the engine and generator, maintaining stable operation of the range extender in power generation mode.

[0055] Once the generator successfully switches to power generation mode and the engine management system enters torque control mode, the mechanical energy output by the engine continuously drives the generator to rotate. The generator converts the mechanical energy into electrical energy for output, and the range extender officially enters the power generation working state to charge the vehicle's power battery.

[0056] In this embodiment, the generator can output torque that matches the current operating condition under different environmental conditions, ensuring the stability and consistency of the starting process under different environmental conditions. By using the speed control mode, the engine is stabilized at the target ignition speed before fuel injection and ignition, improving the ignition success rate. Overall, the NVH quality and reliability of the range extender are improved in different scenarios, enabling the range extender to adapt to different driving scenarios and improving the driving experience of the range-extended electric vehicle.

[0057] In the above Figure 1 Based on the corresponding embodiments, in order to more clearly illustrate the process of forward-driving the engine, this application also provides a possible implementation of forward-driving the engine in the range extender start-up control method. Figure 2 This is a schematic flowchart illustrating the forward-driving engine in a range extender start-up control method provided in an embodiment of this application. Figure 2 As shown, in S102 above, based on the current environmental parameters and the actual torque of the generator in the range extender, the generator is controlled to enter torque control mode, so that the generator drives the engine in the forward direction, including: S210 calculates the feedforward torque of the engine in the range extender based on the current environmental parameters.

[0058] These environmental parameters include, but are not limited to, one or more of the following: ambient temperature, engine downtime, engine coolant temperature, and atmospheric pressure. These environmental parameters directly affect the internal frictional resistance, pumping resistance, and physical properties of the lubricating oil during engine startup.

[0059] Specifically, the vehicle controller collects the aforementioned environmental parameters in real time through various sensors installed on the vehicle and maps each collected environmental parameter to a corresponding torque contribution value. In one possible implementation, the vehicle controller determines the degree of influence of ambient temperature on starting resistance based on ambient temperature, the increase in starting resistance caused by lubricating oil backflow during engine shutdown based on engine shutdown duration, the influence of cylinder block temperature and engine oil temperature on frictional resistance based on engine coolant temperature, and the change in pumping resistance at different altitudes based on atmospheric pressure. The vehicle controller integrates the torque contribution values ​​corresponding to each environmental parameter and calculates the feedforward torque under the current operating conditions using a preset friction torque evaluation model. The feedforward torque represents the theoretical torque value required to overcome the internal resistance of the engine and smoothly drive it to the target speed under the current environmental conditions.

[0060] S220 calculates the target torque based on the feedforward torque, the actual torque of the generator, and the preset torque ramp-up gradient.

[0061] Specifically, the vehicle controller obtains the actual torque of the generator from the generator controller in real time, which is the actual torque value output by the generator. Subsequently, the vehicle controller queries a preset torque ramp-up table based on the current engine speed and the current actual torque of the generator to obtain the maximum allowable torque change in the current control cycle.

[0062] The torque ramp-up gradient table stores the correspondence between each speed range and each torque range and the torque change rate limit value, as shown in Table 3: Table 3 Torque Rise Gradient Table (Unit: Nm / s)

[0063] In Table 3, the horizontal axis represents the current engine speed range in rpm; the vertical axis represents the current generator torque range in Nm. The values ​​stored in the table represent the maximum allowable torque change per second under this operating condition, in Nm / s. For example, when the value in the table is 400, it means that the maximum allowable torque change in 1 second is 400 Nm, which is equivalent to a maximum allowable change of 4 Nm in 10 milliseconds.

[0064] The vehicle controller determines its speed range based on the current engine speed and its torque range based on the actual torque fed back by the generator controller. The value at the intersection of the speed range and the torque range in Table 3 is taken as the maximum torque change rate of the current control cycle, denoted as .

[0065] The vehicle controller calculates the target torque for the current control cycle according to formula (1): Formula (1) in, This indicates the target torque for the current control cycle; This represents the feedforward torque, i.e., the final target value; This indicates the actual torque fed back by the generator controller in the previous control cycle; This represents the torque change rate limit value obtained from Table 3, in Nm / s.

[0066] The meaning of formula (1) above is: taking the actual torque of the previous control cycle as the starting value, and adding the maximum allowable torque change of the current control cycle to obtain an intermediate value, the smaller value between this intermediate value and the feedforward torque is taken as the target torque of the current control cycle. The min function in the formula is used to ensure that the target torque does not exceed the feedforward torque.

[0067] In the first control cycle (i.e. Since the actual torque from the previous control cycle is unavailable, the vehicle controller uses the actual torque fed back by the generator controller at the current moment as the input to the formula, i.e. .in, This represents the current actual torque fed back by the generator controller at the start of the torque control phase. Based on this, starting from the second control cycle, the vehicle controller calculates the target torque cycle by cycle according to formula (1).

[0068] The vehicle controller will calculate the target torque The target torque is sent to the generator controller. The generator controller controls the generator output torque according to the received target torque. In the next control cycle, the vehicle controller again obtains the actual torque fed back from the generator controller as the new target torque. And repeat the above query and calculation operations.

[0069] In this way, the actual torque output by the generator gradually approaches the feedforward torque in each control cycle with a change that does not exceed the preset torque ramp-up gradient, until the feedforward torque is reached. As the control cycle progresses, the actual torque gradually rises to the feedforward torque with a smooth curve, avoiding mechanical shocks and speed fluctuations caused by sudden changes in torque commands.

[0070] S230 controls the generator to enter torque control mode based on the target torque, so that the generator drives the engine in the forward direction.

[0071] Specifically, the generator controller controls the generator according to the target torque value, so that the generator outputs a positive torque corresponding to the target torque, which drives the engine to rotate through the transmission components, so that the engine can accelerate from a standstill.

[0072] During the operation of the generator in torque control mode, the vehicle controller repeats the steps S210 to S230 in each control cycle. That is, in each control cycle, the feedforward torque is recalculated based on the current environmental parameters, and the target torque for the current cycle is calculated based on the actual torque fed back by the generator in real time and the preset torque ramp-up gradient, thereby realizing closed-loop regulation of the generator output torque.

[0073] In this embodiment, by calculating the feedforward torque based on environmental parameters and then approximating the feedforward torque cycle by cycle using gradient filtering, the smooth adjustment of the generator output torque under different environmental conditions is achieved, making the speed increase during engine startup more stable, improving the smoothness of the startup process, and improving the noise, vibration and acoustic roughness performance of the startup process.

[0074] In the above Figure 2Based on the corresponding embodiments, in order to more clearly demonstrate the process of calculating feedforward torque, this application also provides a possible implementation method for calculating feedforward torque in the range extender start-up control method. Figure 3 This is a schematic flowchart illustrating the calculation of feedforward torque in a range extender start-up control method provided in an embodiment of this application. Figure 3 As shown, in S210 above, the calculation of the feedforward torque of the engine in the range extender based on the current environmental parameters includes: In this embodiment, the current environmental parameters include: multiple environmental parameters.

[0075] S310: Based on each environmental parameter, query the preset torque relationship table and the preset weight relationship table to obtain the corresponding basic torque and weight coefficient.

[0076] The preset torque relationship table stores the mapping relationship between each environmental parameter and the base torque, and the preset weight relationship table stores the mapping relationship between each environmental parameter and the weight coefficient.

[0077] Specifically, after acquiring the environmental parameters collected at the current moment, the vehicle controller queries a preset torque relationship table for each environmental parameter to obtain the corresponding base torque. Taking ambient temperature as an example, the vehicle controller queries the preset torque relationship table based on the currently collected ambient temperature value to obtain the base torque value at the ambient temperature. Similarly, the vehicle controller queries the relationship between engine downtime and base torque based on engine downtime, engine coolant temperature, and atmospheric pressure to obtain the base torque value corresponding to each environmental parameter. Each base torque value reflects the individual impact of a single environmental parameter on engine starting resistance.

[0078] Simultaneously, the vehicle controller queries a preset weighting table for each environmental parameter to obtain the corresponding weighting coefficient. The weighting coefficient characterizes the proportion of each environmental parameter in the comprehensive calculation of feedforward torque. Different environmental parameters have varying degrees of influence on starting resistance, therefore their corresponding weighting coefficients also differ. The specific values ​​of the weighting coefficients can be pre-calibrated based on engine bench test data.

[0079] S320 uses the engine's friction torque evaluation model to calculate the feedforward torque based on the weight parameters corresponding to various environmental parameters and the corresponding basic torque.

[0080] After obtaining the base torque and weighting coefficients corresponding to each environmental parameter, the vehicle controller performs a weighted sum of each base torque and its corresponding weighting coefficient to obtain the feedforward torque.

[0081] Specifically, the calculation formula for the friction torque evaluation model is as shown in formula (2): Formula (2) in, Indicates feedforward torque; This indicates the base torque obtained by querying the preset torque relationship table based on the current ambient temperature; This indicates the base torque obtained by querying the preset torque relationship table based on the current engine downtime; This indicates the base torque obtained by querying the preset torque relationship table based on the current engine coolant temperature; This indicates the base torque obtained by querying the preset torque relationship table based on the current atmospheric pressure; , , , These are the weighting coefficients for ambient temperature, engine downtime, engine coolant temperature, and atmospheric pressure, respectively. Each of these weighting coefficients is obtained by querying a preset weighting relationship table.

[0082] The vehicle controller adds the four product terms mentioned above to obtain the feedforward torque value under the current operating conditions. The feedforward torque value is the theoretical torque value required to overcome the various resistance components inside the engine under the current environmental conditions.

[0083] In this embodiment, the basic torque and weight coefficient are obtained by querying the preset torque relationship table and the preset weight relationship table for each environmental parameter. Then, the feedforward torque is obtained by weighted summing of each basic torque and the corresponding weight coefficient. This achieves accurate estimation of engine starting resistance and enables the feedforward torque to be adjusted in real time according to changes in environmental conditions, thereby improving the accuracy of feedforward torque calculation.

[0084] In the above Figure 3 Based on the corresponding embodiments, in order to more clearly demonstrate the process of modifying the preset weight relationship table, this application also provides a possible implementation of modifying the preset weight relationship table in the range extender start-up control method. Figure 4 This is a flowchart illustrating the process of modifying a preset weight relationship table in a range extender start-up control method provided in an embodiment of this application. Figure 4 As shown, based on the above S310-S320, the method further includes: S410, obtains the actual speed curve of the engine during forward drag.

[0085] Specifically, the vehicle controller collects the actual generator speed reported by the generator controller according to a preset sampling period, converts it into engine speed, and stores it in association with the corresponding timestamp to form a speed-time series. When the vehicle controller determines that the engine's first speed has reached the preset speed and exits the torque control mode, it stops recording and uses the entire collected speed-time series as the actual engine speed curve during this startup process.

[0086] The actual speed curve records the complete trajectory of engine speed increase over time during the entire torque control phase, from engine standstill to reaching the preset speed, reflecting the actual changes in engine speed under current environmental conditions and control parameters. Optionally, the actual speed curve can be recorded using an equal-time-interval sampling method, that is, recording one speed data point every fixed sampling period, such as 10 milliseconds or 20 milliseconds.

[0087] S420 determines the speed deviation for this start-up based on the actual speed curve and the preset ideal speed curve.

[0088] The preset ideal speed curve is the optimal speed rise trajectory determined after extensive testing and verification under standard environmental conditions and calibration operating conditions. The ideal speed curve records the ideal speed values ​​at each moment from start-up until the engine reaches the preset speed, representing the optimal speed rise pattern under standard environmental conditions and calibration operating conditions.

[0089] Specifically, since both the actual speed curve and the ideal speed curve are stored in time series form and the sampling time points are consistent, the vehicle controller calculates the difference between the actual speed value and the ideal speed value at each sampling time point.

[0090] In one possible implementation, the ideal speed curve is recorded as the following array:

[0091] Among them, array The first element in Corresponding to the initial speed value at startup, starting from the second element The "start" indicates the rotational speed values ​​at each sampling time after startup.

[0092] The vehicle controller extracts the speed values ​​at the corresponding sampling time from the actual speed curve to form an actual speed array:

[0093] in, This represents the actual rotational speed at the initial moment of startup. to This represents the actual rotational speed values ​​at each sampling time after startup. Since the rotational speed is zero at the initial startup time, the actual rotational speed array... The first element in With ideal speed array The first element in All are zero, and the comparison starts from the second element when calculating the deviation.

[0094] The vehicle controller calculates the speed deviation for this start-up according to formula (3): Formula (3) in, This indicates the speed deviation value for this startup; Indicates the sequence number of the sampling point; Indicating the first [unit] in the actual speed curve Rotational speed values ​​at each sampling point; In the ideal speed curve, the first... Rotational speed values ​​at each sampling point; Indicates the first The weighting coefficients corresponding to each sampling point are preset based on engineering experience and are used to adjust the contribution of different speed stages in the deviation calculation.

[0095] like A value less than zero indicates that the actual engine speed is generally higher than the ideal speed during startup, meaning the engine speed rises too quickly, resulting in speed overshoot. This suggests that the feedforward torque calculated using the current weighting coefficients is too high. A value greater than or equal to zero indicates that the actual speed is lower than the ideal speed during startup, and the engine speed rises too slowly, indicating that the feedforward torque calculated by the weighting coefficients used is too small.

[0096] S430, based on the speed deviation, corrects the preset weight relationship table.

[0097] Specifically, the vehicle controller calculates the correction factor for each environmental parameter based on the actual values ​​of the currently collected environmental parameters, and then calculates the correction factor based on the speed deviation. Calculate the updated weight coefficients. Optionally, the adjustment factor can be between 0.2 and 0.5.

[0098] The vehicle controller first calculates the correction factor corresponding to the ambient temperature. The preset ambient temperature range is denoted as []. , [, e.g., [-40, 60], in °C, to set the reference temperature. The ambient temperature is 25℃. Tests show that engine starting torque increases as ambient temperature decreases. The calculation is divided into two cases: when A value less than zero indicates that the engine speed has overshooted during startup, meaning the actual speed is higher than the ideal speed. In this case, the feedforward torque is too high. The calculation formula is as shown in formula (4): Formula (4) in, This represents the current ambient temperature recorded during self-learning. This indicates a reference temperature of 25℃. This represents the upper limit of the preset ambient temperature range. The `max` function is used to ensure... It is a non-negative value.

[0099] when A value greater than or equal to zero indicates insufficient speed increase during startup, with the actual speed lower than the ideal speed. In this case, the feedforward torque is too small. The calculation formula is as shown in formula (5): Formula (5) in, This indicates the lower limit of the preset ambient temperature range.

[0100] The vehicle controller calculates the correction factor corresponding to the downtime. The preset downtime range is [0, ...]. The unit is seconds, and the base duration is set to 0. Tests show that the engine starting torque increases with the duration of inactivity. The calculation is divided into two cases: when When the value is less than zero, it indicates that the feedforward torque is too large. In this case, the downtime is not considered a primary correction factor. The value is 0, that is .

[0101] when When the value is greater than or equal to zero, it indicates that the feedforward torque is too small. In this case, the starting torque needs to be corrected based on the downtime. The calculation formula is as shown in formula (6): Formula (6) in, This indicates the current downtime recorded during self-learning. This indicates the upper limit of the preset downtime range. This is the upper limit of the weight of the downtime in relation to the change in starting torque, and is generally taken as 0.2.

[0102] The vehicle controller calculates the correction factor corresponding to the engine coolant temperature. The preset engine coolant temperature range is denoted as []. , [, e.g., [-40, 120], in °C, setting the reference water temperature. The temperature is 25℃. Tests show that the engine starting torque increases as the engine coolant temperature decreases. The calculation is divided into two cases: when A value less than zero indicates that the feedforward torque is too large. The calculation formula is as shown in formula (7): Formula (7) in, This indicates the current engine coolant temperature recorded during self-learning. This indicates a reference water temperature of 25℃. This indicates the upper limit of the preset water temperature range.

[0103] when A value greater than or equal to zero indicates that the feedforward torque is too small. The calculation formula is as shown in formula (8): Formula (8) in, This indicates the lower limit of the preset water temperature range.

[0104] The vehicle controller calculates the correction factor corresponding to atmospheric pressure. The preset atmospheric pressure range is denoted as [ ]. , [550, 1030], for example, the unit is hPa, which sets the reference atmospheric pressure. The pressure is 1013 hPa. Tests show that the engine's pumping resistance torque decreases as atmospheric pressure decreases. The calculation is divided into two cases: when A value less than zero indicates that the feedforward torque is too large. The calculation formula is as shown in formula (9): Formula (9) in, This represents the current atmospheric pressure recorded during the learning process. This indicates a reference atmospheric pressure of 1013 hPa. This indicates the lower limit of the preset atmospheric pressure range.

[0105] when A value greater than or equal to zero indicates that the feedforward torque is too small. The calculation formula is as shown in formula (10): Formula (10) in, This indicates the upper limit of the preset atmospheric pressure range.

[0106] The vehicle controller calculates , , , Then, based on each correction factor and speed deviation... Calculate the updated values ​​of each weight coefficient. For the Weighting coefficients for each environmental parameter Its update method is based on the speed deviation. The symbols are calculated using different formulas.

[0107] when When the value is less than zero, it indicates that the speed overshoot occurs during startup and the feedforward torque is too large. In this case, it is necessary to reduce the weighting coefficient and update the reference formula (11): Formula (11) when When the value is greater than or equal to zero, it indicates that the speed increase during the start-up process is insufficient and the feedforward torque is too small. In this case, it is necessary to increase the weighting coefficient and update the reference formula (12): Formula (12) in, The values ​​are 1, 2, 3, and 4, which correspond to four environmental parameters: ambient temperature, engine downtime, engine coolant temperature, and atmospheric pressure, respectively. Indicates the first Correction factors corresponding to each environmental parameter; For speed deviation; Indicates the first The current value of the weight coefficient corresponding to each environmental parameter; Indicates the first The updated values ​​of the weight coefficients corresponding to each environmental parameter are used for the next use.

[0108] The vehicle controller stores the updated weighting coefficients, overwriting the original values. Each startup updates the coefficients for the corresponding ambient temperature range and stores the entire update in non-volatile memory. For example, ambient temperature and weighting coefficients... The correspondence is shown in Table 4: Table 4 Ambient Temperature and Weighting Coefficients Correspondence

[0109] Table 4 provides an example of the relationship between ambient temperature and... The correspondence is such that, in actual storage, the weighting coefficients corresponding to each environmental parameter are stored separately according to parameter ranges in a similar manner. Upon the next startup, the vehicle controller reads the weighting coefficients for the corresponding temperature range based on the current ambient temperature, and combines them with the weighting coefficients corresponding to other environmental parameters to calculate the feedforward torque, thereby gradually bringing the actual speed curve of the next startup closer to the ideal speed curve.

[0110] In this embodiment, by calculating the correction factors for each environmental parameter separately and independently correcting each weight coefficient according to the speed deviation, the adjustment of each weight coefficient can accurately reflect the actual impact of the corresponding environmental parameter on the starting torque, thus achieving fine-grained adaptive adjustment of the weight coefficients. Simultaneously, by storing the updated weight coefficients in segments according to ambient temperature, the weight coefficients in each temperature segment can be independently optimized, further improving the adaptability of the feedforward torque calculation accuracy under different environmental conditions.

[0111] In the above Figure 1 Based on the corresponding embodiments, in order to more clearly demonstrate the process of switching speed control modes, this application also provides a possible implementation method for switching speed control modes in the range extender start-up control method. Figure 5 This is a flowchart illustrating the switching of speed control mode in a range extender start-up control method provided in an embodiment of this application. Figure 5 As shown, in S104 above, if the engine's first speed reaches the preset speed, controlling the generator to switch from torque control mode to speed control mode includes: S510, obtain the preset first target control speed.

[0112] After determining that the engine's first speed has reached a preset speed, the vehicle controller acquires a preset first target control speed. The first target control speed is a pre-stored speed value, which is greater than the preset speed but less than the ignition target speed. Optionally, this first target control speed can be a pre-calibrated fixed value, such as 1000 rpm; or it can be an optimized value stored after self-learning during the initial startup process. The specific value of the first target control speed can be set according to actual application requirements, and its value lies between the preset speed and the ignition target speed.

[0113] S520, based on the first target control speed, controls the generator to switch from torque control mode to speed control mode in the first speed control stage.

[0114] After acquiring the first target control speed, the vehicle controller sends a speed control mode switching command to the generator controller, and sends the first target control speed as the target value for the current speed control stage. Upon receiving the command, the generator controller switches the generator's control mode from torque control mode to speed control mode. In speed control mode, the generator controller uses the received first target control speed as the target value to adjust the generator's output torque, causing the generator's actual speed to approach and eventually stabilize at the first target control speed.

[0115] The phase in which the generator controller operates with the first target control speed as the target value in speed control mode is called the first speed control phase. During the first speed control phase, the vehicle controller continuously monitors the engine speed fed back by the generator controller to confirm whether the engine speed has stabilized near the first target control speed. Optionally, when the engine speed remains within the preset allowable fluctuation range of the first target control speed for several consecutive control cycles, the vehicle controller determines that the engine speed has stabilized at the first target control speed.

[0116] S530: After the generator enters the first speed control stage, if the engine speed reaches the first target control speed, the ignition target speed will be used as the second target control speed.

[0117] After determining that the engine speed has reached the first target control speed, the vehicle controller acquires the preset ignition target speed and sets it as the second target control speed. The ignition target speed is a pre-stored speed value, which is higher than the first target control speed and represents the minimum speed at which engine fuel injection and ignition are permitted. Optionally, the ignition target speed can be calibrated according to the engine's mechanical characteristics and starting performance requirements, for example, set to 1100 rpm.

[0118] S540 controls the generator to enter the second speed control stage from the first speed control stage according to the second target control speed.

[0119] The vehicle controller sends the second target control speed to the generator controller. Upon receiving the second target control speed, the generator controller adjusts its speed control target value from the first target control speed to the second target control speed, and uses this second target control speed as the new target value to continue adjusting the generator's output torque. This process ensures that the generator's actual speed smoothly increases from the first target control speed to the second target control speed and eventually stabilizes near the second target control speed. This stage, where the generator controller operates with the second target control speed as the target value, is called the second speed control stage.

[0120] During the second speed control phase, the vehicle controller continuously monitors the engine speed fed back by the generator controller to confirm whether the engine speed has stabilized near the second target control speed. Once the engine speed stabilizes at the ignition target speed, the vehicle controller considers the engine to be ready for fuel injection and ignition, and can proceed to the subsequent fuel injection and ignition control process.

[0121] In this embodiment, by setting a first target control speed that is less than the ignition target speed, and then switching to the second speed control stage with the ignition target speed as the target value after the engine speed stabilizes at the first target control speed, the large speed jump caused by directly using the ignition target speed as the control target is avoided, the overshoot and stabilization time in the speed control process are reduced, and the smoothness and response quality of speed control are improved.

[0122] In the above Figure 5 Based on the corresponding embodiments, to more clearly demonstrate the process of obtaining a preset first target control speed, this application also provides a possible implementation of obtaining a preset first target control speed in a range extender start-up control method. Optionally, in the above S510, obtaining the preset first target control speed includes: S610, obtain the pre-stored first target control speed. The first target control speed is the speed calculated based on the engine's maximum speed, preset base speed, and ignition target speed during the last start-up process. The preset base speed is any speed value that is greater than the preset speed and less than the ignition target speed.

[0123] In this embodiment, the first target control speed is obtained through a self-learning method. Specifically, the vehicle controller calculates the first target control speed according to formula (13): Formula (13) in, This indicates the first target control speed used in this operation; 1000 indicates the preset base speed, in revolutions per minute. This indicates the correction ratio factor; 1100 indicates the target ignition speed, in revolutions per minute. This indicates the maximum engine speed recorded during the last start-up process when the engine transitioned from the first target control speed to the ignition target speed.

[0124] The preset base speed refers to a fixed speed value set in advance, which is greater than the target speed but less than the ignition target speed. It is used to provide a safe starting point for calculating the first target control speed. The preset base speed can be calibrated according to the engine's mechanical characteristics and starting performance requirements, for example, set to 1000 rpm.

[0125] Due to the influence of actual environment and vehicle condition, the preset base speed of 1000 rpm is not the optimal value under all operating conditions. After each successful start-up, the vehicle controller records the maximum speed during the transition from the first speed control stage to the second speed control stage during this start-up process. Then, substitute it into the above formula to calculate the new first target control speed, and store it for use in the next startup. To correct the proportional gain, a value ranging from 0.3 to 0.5 is used to control the self-learning convergence speed. Through the above self-learning method, the first target control speed can be gradually optimized during multiple startups, resulting in a smoother speed transition.

[0126] In this embodiment, by pre-storing and retrieving the first target control speed, a clear and stable first-stage control target can be provided for the generator to switch from torque control mode to speed control mode. The first target control speed is continuously optimized through self-learning, enabling it to adapt to the starting requirements of different environments and vehicle conditions, resulting in a smoother speed transition and further improving the adaptability and accuracy of speed control.

[0127] In the above Figure 1 Based on the corresponding embodiments, to more clearly demonstrate the process of abnormal exit from torque control mode, this application also provides a possible implementation of abnormal exit from torque control mode in the range extender start-up control method. Optionally, based on the above S101-S107, the method further includes: S710 If the duration of the torque control mode exceeds the preset duration and the first speed does not reach the preset speed, or if the engine speed decreases by more than the preset decrease, the generator is controlled to switch from the torque control mode to the speed control mode.

[0128] During the process of the generator driving the engine in torque control mode, the vehicle controller continuously monitors the duration of torque control mode operation and the engine speed changes, and determines whether it is necessary to exit torque control mode in advance based on the monitoring results.

[0129] On one hand, the vehicle controller times the duration of the torque control mode and compares the accumulated time with the preset time in each control cycle. If the accumulated time exceeds the preset time, and the engine's initial speed has not yet reached the preset speed, it indicates that under the current environmental conditions and torque output, the generator cannot drive the engine to the target speed within the expected time. In this case, continuing to maintain the torque control mode may lead to overheating due to prolonged high torque. Therefore, the vehicle controller switches the generator from torque control mode to speed control mode. Optionally, the preset time can be calibrated according to the actual application scenario, for example, set to 2000 milliseconds.

[0130] On the other hand, during the process of the generator driving the engine in torque control mode, the vehicle controller calculates the difference between the current engine speed and the engine speed in the previous control cycle in each control cycle, as the speed change. When the cumulative decrease in speed exceeds the preset decrease amount, it indicates that the engine has not only failed to be effectively driven to increase speed, but its speed has also decreased. At this time, if the torque control mode is maintained, the speed may decrease further or even drop to zero, leading to start-up failure or other safety issues. Therefore, when the engine speed decrease exceeds the preset decrease amount, the vehicle controller also controls the generator to switch from torque control mode to speed control mode. Optionally, the preset decrease amount can be calibrated according to the actual application scenario, for example, set to 20 rpm.

[0131] When any of the above conditions are met, the vehicle controller sends a mode switching command to the generator controller, instructing the generator controller to switch the generator's control mode from torque control mode to speed control mode. After entering speed control mode, the generator uses the target speed sent by the vehicle controller as the control target, stabilizing the engine speed near the target speed.

[0132] In this embodiment, by monitoring the duration of the torque control mode and the trend of engine speed change, and exiting the torque control mode in advance and switching to the speed control mode when a timeout occurs or the speed drops abnormally, the robustness and safety of the startup process are improved.

[0133] In the above Figure 1 Based on the corresponding embodiments, to more clearly illustrate the process of controlling engine fuel injection and ignition, this application also provides a possible implementation of controlling engine fuel injection and ignition in a range extender start-up control method. Optionally, in the above S106, controlling engine fuel injection and ignition includes: S810 controls the engine to enter idle speed control mode according to the preset engine idle speed, and controls the engine to perform fuel injection and ignition in idle speed control mode.

[0134] The preset engine idle speed is greater than the ignition target speed.

[0135] After determining that the engine's second rotational speed has reached the target ignition speed, the vehicle controller sends a fuel injection and ignition command to the engine management system and instructs the engine management system to control the engine to enter idle speed control mode. Idle speed control mode refers to the operating mode of the engine management system during engine startup, where a preset engine idle speed is used as the control target.

[0136] In idle speed control mode, the engine management system uses a preset engine idle speed as the target value and automatically adjusts the fuel injection and intake air volume through its internal idle closed-loop control algorithm. This allows the engine to maintain operation after ignition and converge towards the preset engine idle speed. Because the preset engine idle speed is higher than the ignition target speed, when the engine management system controls the engine to run, the idle speed is higher than the current ignition target speed. This speed deviation prompts the engine management system to output a larger fuel injection and intake air volume, ensuring that the torque generated by the engine after ignition is sufficient to overcome its internal resistance and allow it to continue accelerating.

[0137] Meanwhile, during engine injection and ignition, the vehicle controller continues to keep the generator in speed control mode, using the ignition target speed as the control target to continuously stabilize the engine speed. Through the combined effects of generator speed control and engine idle speed control, the engine speed fluctuation at the moment of ignition is effectively suppressed. Once the engine successfully ignites and enters idle speed control mode, the engine management system controls the engine to maintain the preset idle speed, and the generator no longer needs to output positive torque for operation.

[0138] In this embodiment, the preset engine idle speed is greater than the ignition target speed, so that the target operating speed of the engine after fuel injection and ignition is higher than the speed maintained by the current generator. This helps the engine to quickly reach the ignition target speed and enter a stable operating state after ignition, avoiding the possibility of the engine speed dropping after starting due to the preset engine idle speed being lower than or equal to the ignition target speed, thus improving the start-up success rate and operating stability of the engine after fuel injection and ignition.

[0139] In the above Figure 1 Based on the corresponding embodiments, in order to more clearly demonstrate the process of determining successful engine ignition, this application also provides a possible implementation method for determining successful engine ignition in the range extender start-up control method. Figure 6 This is a schematic diagram illustrating the process of determining successful engine ignition in a range extender start-up control method provided in an embodiment of this application. Figure 6 As shown, in S107 above, before switching the generator to power generation mode after successful engine ignition, the method further includes: The S910 continuously monitors the feedback torque of the generator after controlling the engine's fuel injection and ignition.

[0140] Specifically, before engine fuel injection and ignition, the generator is in speed control mode. To maintain the engine speed at the target ignition speed, the generator needs to output positive torque to overcome the engine's internal frictional resistance. At this time, the generator's feedback torque is positive and relatively large. After engine fuel injection and ignition, the engine begins to burn fuel and generate positive torque. The vehicle controller continues to keep the generator in speed control mode, maintaining the target ignition speed as the control target. However, as the engine's own output torque gradually increases, the external torque required to maintain the speed gradually decreases. Therefore, the generator's feedback torque gradually decreases from a positive value.

[0141] The vehicle controller continuously receives feedback torque reported by the generator controller according to a preset control cycle, and compares the received feedback torque with a preset threshold in each control cycle to determine the trend and current value level of the feedback torque.

[0142] S920: If the feedback torque is less than the preset threshold, the engine is determined to have started successfully.

[0143] Specifically, once the engine successfully ignites and begins to burn power, its own torque output gradually increases, and the external drive requirement of the generator gradually decreases. When the engine's own torque output is sufficient to overcome its internal frictional resistance and maintain the current speed, the generator no longer needs to output positive torque to drive the engine, and the feedback torque at this point approaches zero. When the engine's output torque further increases to exceed the torque required to maintain the current speed, the engine will begin to drive the generator in reverse, at which point the generator's feedback torque becomes negative.

[0144] Therefore, the preset threshold can be set to a positive value close to zero, such as 10 Nm. When the feedback torque continuously decreases from a positive value to below the preset threshold, it indicates that the engine can independently maintain operation and begin to reverse-drive the generator, and the vehicle controller determines that the engine ignition is successful. The preset threshold can be calibrated according to the specific characteristics of the engine and generator.

[0145] After determining that the engine ignition is successful, the vehicle controller will execute the subsequent power generation mode switching process, that is, control the generator to switch from speed control mode to power generation mode.

[0146] In this embodiment, by continuously monitoring the feedback torque of the generator after the engine injects fuel and ignites, and using whether the feedback torque is less than a preset threshold as the criterion for determining successful ignition, the engine ignition status is effectively detected, and the reliability of the ignition success determination is improved.

[0147] Based on the above embodiments, this application also provides a fault diagnosis strategy during the startup process.

[0148] The vehicle controller continuously monitors the execution of the start-up process during the range extender startup. When the cumulative duration of the startup process exceeds the preset total timeout (e.g., 8 seconds), the vehicle controller directly determines that the startup has failed. In addition, if the engine is already running but the speed is lower than the preset speed threshold (e.g., 600 rpm), the vehicle controller also determines that the startup has failed.

[0149] After each failed start-up attempt, the vehicle controller accumulates the number of failures. After a single failure, the vehicle controller does not immediately retry the start-up process, but instead pauses the start-up procedure and waits for a preset waiting time (e.g., 5 seconds) before allowing the next start-up attempt. Within a single power-on / off cycle, the vehicle controller allows a maximum of five start-up failures.

[0150] When the cumulative number of failed starts reaches a preset redundant start trigger threshold (e.g., three times), the vehicle controller switches the start strategy and uses a redundant start strategy to perform subsequent start attempts. Under the redundant start strategy, the vehicle controller directly controls the generator to drive the engine to the target speed (e.g., 1100 rpm) in speed control mode. After the engine injects fuel and ignites, the vehicle controller controls the generator to maintain the speed control mode for a preset duration (e.g., 5 seconds), and then controls the generator to switch to generator mode. The total timeout duration under the redundant start strategy is longer than the total timeout duration under the conventional start strategy, for example, set to 13 seconds.

[0151] In this way, the conventional startup strategy automatically switches to a redundant startup strategy after multiple failures, ensuring both startup reliability and startup quality.

[0152] During the range extender start-up control process, the vehicle controller acts as the main control unit, interacting with the sensors, generator controller, and engine management system. Figure 7 An interactive block diagram of a range extender start-up control method provided in this application embodiment is shown below. Figure 7 As shown in the diagram, this interactive block diagram illustrates the signal flow between the various control units during the start-up process of the range extender.

[0153] First, the vehicle controller obtains the current ambient temperature from sensors and receives feedback from the engine management system (EMS) regarding coolant temperature, atmospheric pressure, and engine downtime. Based on these environmental parameters and the current torque fed back by the generator controller, the vehicle controller calculates the target torque and sends a request for a GCU control mode to the generator controller. This request includes a torque control mode, and simultaneously sends the requested target torque, as well as the requested maximum and minimum permissible torques. Upon receiving these instructions, the generator controller, within the torque range defined by the requested maximum and minimum permissible torques, controls the generator to drive the engine forward according to the target torque, causing the engine speed to increase from zero. In torque control mode, the generator controller feeds back the current engine speed and torque to the vehicle controller in real time.

[0154] During the process of controlling the generator to drive the engine in torque control mode, the vehicle controller continuously acquires the current speed fed back by the generator controller and calculates the engine's first speed based on the mechanical transmission ratio between the current speed and the engine. The vehicle controller compares the first speed with a preset speed. When the first speed reaches the preset speed, the vehicle controller sends a mode switching command to the generator controller, switching the control mode from torque control mode to speed control mode, and simultaneously sends a request for a target speed to the generator controller. Specifically, the vehicle controller reads the preset first target control speed and sends it as the target value for the current speed control stage to the generator controller. The generator controller adjusts the generator's output torque using the first target control speed as the target value to stabilize the engine speed at the first target control speed. After the engine speed stabilizes at the first target control speed, the vehicle controller sets the ignition target speed as the second target control speed and sends it to the generator controller. The generator controller uses the second target control speed as the target value to stabilize the engine speed at the ignition target speed.

[0155] After the engine speed stabilizes at the target ignition speed, the vehicle controller sends a request for fuel injection permission and a request to start command to the engine management system. Simultaneously, it sends a request for idle speed, specifying a preset engine idle speed that is greater than the target ignition speed. Upon receiving these commands, the engine management system controls the engine to enter idle speed control mode and performs fuel injection and ignition at the preset engine idle speed as the target value. During engine fuel injection and ignition, the vehicle controller continues to maintain the alternator in speed control mode, ensuring the alternator continuously stabilizes the engine speed at the target ignition speed. The engine management system also provides real-time feedback on the current status and torque to the vehicle controller, enabling the vehicle controller to monitor the engine's operating status in real time.

[0156] After engine fuel injection and ignition, the vehicle controller continuously monitors the current torque fed back by the generator controller. As the engine begins to burn and generate power, its own output torque gradually increases, while the external torque required to maintain the current speed gradually decreases. Consequently, the current torque fed back by the generator controller gradually decreases from a positive value. When the vehicle controller detects that the current torque is less than a preset threshold, it determines that engine ignition has been successful. At this point, the vehicle controller sends a request to the generator controller to switch the control mode from speed control mode to power generation mode, and the range extender enters power generation operation.

[0157] During the above process, the vehicle controller also receives feedback on the current status and current torque from the engine management system to monitor the engine's operating status in real time. When the vehicle controller detects an abnormal drop in engine speed or a torque control mode lasting longer than a preset duration, it triggers an abnormal exit mechanism.

[0158] Through the above control interaction methods, a closed-loop control link is formed between the vehicle controller, the generator controller, and the engine management system, realizing a smooth transition and precise control at each stage during the start-up process of the range extender.

[0159] The following describes the range extender start control device and vehicle controller provided in this application, which are used to implement the application. The specific implementation process and technical effects are described above and will not be repeated below.

[0160] Figure 8 A schematic diagram of a range extender start-up control device provided in an embodiment of this application is shown below. Figure 8 As shown, the range extender start-up control device includes: The control module 1000 is used to control the generator in the range extender to drive the engine in reverse if the preset starting conditions of the range extender are met; after the reverse driving ends, the generator is controlled to enter the torque control mode according to the current environmental parameters and the actual torque of the generator in the range extender, so that the generator drives the engine in the forward direction.

[0161] The acquisition module 2000 is used to acquire the first engine speed after the generator enters the torque control mode.

[0162] The control module 1000 is also used to control the generator to switch from torque control mode to speed control mode if the engine's first speed reaches the preset speed.

[0163] The acquisition module 2000 is also used to acquire the second engine speed after the generator enters the speed control mode.

[0164] The control module 1000 is also used to control the engine to inject fuel and ignite if the second speed of the engine reaches the ignition target speed; and to control the generator to switch to power generation mode after the engine ignition is successful.

[0165] Optionally, the range extender start-up control device also includes a calculation module 3000, which is used to calculate the feedforward torque of the engine in the range extender based on the current environmental parameters; and to calculate the target torque based on the feedforward torque, the actual torque of the generator, and the preset torque ramp-up gradient.

[0166] Optionally, the control module 1000 is specifically used to control the generator to enter torque control mode according to the target torque, so that the generator drives the engine in the forward direction.

[0167] Optionally, the calculation module 3000 is specifically used for the current environmental parameters including: multiple environmental parameters; according to each environmental parameter, query the preset torque relationship table and the preset weight relationship table respectively to obtain the corresponding basic torque and weight coefficient; wherein, the preset torque relationship table stores the mapping relationship between each environmental parameter and the basic torque, and the preset weight relationship table stores the mapping relationship between each environmental parameter and the weight coefficient; according to the weight parameters corresponding to the multiple environmental parameters and the corresponding basic torque, the engine friction torque evaluation model is used to calculate the feedforward torque.

[0168] Optionally, the acquisition module 2000 is also used to acquire the actual speed curve of the engine during the forward drag process.

[0169] Optionally, the calculation module 3000 is also used to determine the speed deviation of this start-up based on the actual speed curve and the preset ideal speed curve; and to correct the preset weight relationship table based on the speed deviation.

[0170] Optionally, the acquisition module 2000 is also used to acquire a preset first target control speed.

[0171] Optionally, the control module 1000 is specifically used to control the generator to switch from torque control mode to speed control mode in the first speed control stage according to the first target control speed; after the generator enters the first speed control stage, if the engine speed reaches the first target control speed, the ignition target speed is used as the second target control speed; according to the second target control speed, the generator is controlled to enter the second speed control stage from the first speed control stage.

[0172] Optionally, the acquisition module 2000 is specifically used to acquire a pre-stored first target control speed. The first target control speed is a speed calculated based on the engine's maximum speed, preset base speed, and ignition target speed during the last start-up process. The preset base speed is any speed value that is greater than the preset speed and less than the ignition target speed.

[0173] Optionally, the control module 1000 is also used to control the generator to switch from torque control mode to speed control mode if the duration of torque control mode exceeds a preset duration and the first speed does not reach the preset speed, or if the engine speed drops by more than a preset amount.

[0174] Optionally, the control module 1000 is specifically used to control the engine to enter the idle speed control mode according to the preset engine idle speed, and to control the engine to perform fuel injection and ignition in the idle speed control mode; the preset engine idle speed is greater than the ignition target speed.

[0175] Optionally, the range extender start control device also includes a determination module 4000, which continuously monitors the feedback torque of the generator after controlling the engine to inject fuel and ignite; if the feedback torque is less than a preset threshold, the engine is determined to have ignited successfully.

[0176] These modules can be one or more integrated circuits configured to implement the above methods, such as one or more Application Specific Integrated Circuits (ASICs), one or more digital signal processors (DSPs), or one or more Field Programmable Gate Arrays (FPGAs). Alternatively, when a module is implemented using processing element scheduler code, the processing element can be a general-purpose processor, such as a Central Processing Unit (CPU) or other processor capable of calling program code. Furthermore, these modules can be integrated together as a system-on-a-chip (SOC).

[0177] Figure 9 This is a schematic diagram of a vehicle controller provided in an embodiment of this application.

[0178] The vehicle controller 10 includes a processor 11, a storage medium 12, and a bus 13. The storage medium 12 stores program instructions executable by the processor 11. When the vehicle controller 10 is executed, the processor 11 communicates with the storage medium 12 via the bus 13, and the processor 11 executes the program instructions to perform the above-described method embodiment. The specific implementation and technical effects are similar and will not be described in detail here.

[0179] Optionally, this application also provides a program product, such as a computer-readable storage medium, including a program that, when executed by a processor, performs the above-described method embodiments.

[0180] Based on the vehicle controller provided in the above embodiments, this application also provides a possible implementation of a range-extended electric vehicle. The range-extended electric vehicle includes: a vehicle body, a vehicle controller, and a range extender. The range extender includes a generator, an engine, a generator controller, and an engine management system. Both the vehicle controller and the range extender are mounted on the vehicle body. The generator controller is connected to the generator, the engine management system is connected to the engine, and the vehicle controller is connected to both the generator controller and the engine management system, respectively, for executing the range extender start-up control method as described in any of the above embodiments.

[0181] Based on the same inventive concept, the range-extended electric vehicle has the range extender start-up control function as described in any of the above embodiments, and has the beneficial effects of the corresponding embodiments, which will not be repeated here.

[0182] It should be understood that the disclosed apparatus and methods can be implemented in other ways, as illustrated in the several embodiments provided in this application. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0183] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0184] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or in a combination of hardware and software functional units.

[0185] The integrated units implemented as software functional units described above can be stored in a computer-readable storage medium. These software functional units, stored in a storage medium, include several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) or processor to execute some steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0186] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for starting control of a range extender, characterized in that, The method includes: If the preset starting conditions of the range extender are met, the generator in the range extender is controlled to reverse and drive the engine. After the reverse drag ends, based on the current environmental parameters and the actual torque of the generator, the generator is controlled to enter the torque control mode, so that the generator drags the engine in the forward direction; After the generator enters the torque control mode, the first speed of the engine is obtained; If the first speed of the engine reaches the preset speed, the generator is controlled to switch from the torque control mode to the speed control mode; After the generator enters the speed control mode, the second speed of the engine is obtained; If the second speed of the engine reaches the target ignition speed, control the engine to inject fuel and ignite. After the engine is successfully ignited, the generator is switched to power generation mode.

2. The method according to claim 1, characterized in that, The step of controlling the generator to enter torque control mode based on the current environmental parameters and the actual torque of the generator in the range extender, so that the generator drives the engine in the forward direction, includes: Calculate the feedforward torque of the engine in the range extender based on the current environmental parameters; The target torque is calculated based on the feedforward torque, the actual torque of the generator, and the preset torque ramp-up gradient. Based on the target torque, the generator is controlled to enter torque control mode, so that the generator drives the engine in the forward direction.

3. The method according to claim 2, characterized in that, The current environmental parameters include: multiple environmental parameters; the calculation of the feedforward torque of the engine in the range extender based on the current environmental parameters includes: For each environmental parameter, a preset torque relationship table and a preset weight relationship table are queried to obtain the corresponding base torque and weight coefficient; wherein, the preset torque relationship table stores the mapping relationship between each environmental parameter and the base torque, and the preset weight relationship table stores the mapping relationship between each environmental parameter and the weight coefficient. The feedforward torque is calculated using the friction torque evaluation model of the engine, based on the weight parameters corresponding to the various environmental parameters and the corresponding base torque.

4. The method according to claim 3, characterized in that, The method further includes: Obtain the actual speed curve of the engine during the forward drag process; Based on the actual speed curve and the preset ideal speed curve, determine the speed deviation for this start-up; The preset weighted relationship table is corrected based on the speed deviation.

5. The method according to claim 1, characterized in that, The control of the generator to switch from the torque control mode to the speed control mode includes: Obtain the preset first target control speed; Based on the first target control speed, the generator is controlled to switch from the torque control mode to the speed control mode in the first speed control phase; After the generator enters the first speed control stage, if the engine speed reaches the first target control speed, the ignition target speed is taken as the second target control speed. Based on the second target control speed, the generator is controlled to enter the second speed control stage from the first speed control stage.

6. The method according to claim 5, characterized in that, The process of obtaining the preset first target control speed includes: Obtain the first target control speed that is stored in advance. The first target control speed is a speed calculated based on the maximum speed of the engine, the preset base speed and the ignition target speed during the last start-up process. The preset base speed is any speed value that is greater than the preset speed and less than the ignition target speed.

7. The method according to claim 1, characterized in that, The method further includes: If the duration of the torque control mode exceeds a preset duration and the first speed does not reach the preset speed, or if the engine speed decreases by more than a preset decrease, the generator is controlled to switch from the torque control mode to the speed control mode.

8. The method according to claim 1, characterized in that, The control of engine fuel injection and ignition includes: Based on a preset engine idle speed, the engine is controlled to enter an idle speed control mode, and in the idle speed control mode, the engine is controlled to perform fuel injection and ignition, wherein the preset engine idle speed is greater than the target ignition speed.

9. The method according to claim 1, characterized in that, Before controlling the generator to switch to power generation mode after the engine has successfully ignited, the method further includes: After controlling the engine's fuel injection and ignition, the feedback torque of the generator is continuously monitored; If the feedback torque is less than a preset threshold, the engine is determined to have ignited successfully.

10. A range-extended electric vehicle, characterized in that, The range-extended electric vehicle includes: a vehicle body, a vehicle controller, and a range extender. The range extender includes: a generator, an engine, a generator controller, and an engine management system. The vehicle controller and the range extender are both mounted on the vehicle body. The generator controller is connected to the generator, and the engine management system is connected to the engine. The vehicle controller is connected to both the generator controller and the engine management system. The vehicle controller is used to execute the range extender start-up control method as described in any one of claims 1 to 9.

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