Shutdown control method of range extender, electronic equipment and range-extended automobile

Abstract

The invention belongs to the field of new energy automobiles, and particularly relates to a shutdown control method of a range extender, electronic equipment and a range-extended automobile, the rotation angle of a crankshaft is divided into a low resistance interval, a uniform resistance interval and a high resistance interval according to the piston resistance change of a compression stroke; the method comprises the steps that the generator is in a rotating speed mode and maintains a constant rotating speed, and engine fuel cut-off is requested; when the crankshaft is located in the low-resistance interval, the power generator is switched into a torque mode and maintains constant torque, and the engine enters a shutdown process under frictional resistance; when the rotating speed of the engine is lower than the rotating speed threshold value, the generator applies different negative torques based on resistance changes of an engine piston, and the engine is pressed and stopped. Compared with the prior art, the problem that in the prior art, abnormal sounds are generated when the range extender stops is solved, the increase of the pressure stop torque of the generator is controlled through the interval where the crankshaft is located, the total stop torque is increased more smoothly, and then the probability of the abnormal sounds in the stop process is reduced.

Description

Technical Field

[0001] The present invention belongs to the field of new energy vehicles, and in particular relates to a shutdown control method of a range extender, an electronic device and a range-extended vehicle. Background Art

[0002] As a technical branch of new energy vehicles, extended-range vehicles are currently quite popular in the market. Extended-range vehicles use electric drive as the main power source and are further equipped with an internal combustion engine as a range extender, which can charge the battery when the battery is exhausted or about to be exhausted, thereby achieving the purpose of extending the vehicle's cruising range. This design takes into account the characteristics of environmental protection and energy saving as well as the problem of insufficient battery life. Therefore, extended-range vehicles are popular among consumers.

[0003] At present, during the shutdown process of the range extender, various manufacturers on the market generally use the method of cutting off the engine oil and braking the motor to quickly reduce the speed of the range extender to 0 speed; however, the shutdown process of the range extender is difficult to control and is prone to noise and vibration. This is because: the engine and generator of the range extender are connected by a torsional damper, and during the shutdown process, the relative speed between the engine and the generator will change between positive and negative. This process causes the spring of the torsional damper to be squeezed back and forth, causing abnormal noise. The reason for the change in the relative speed between the generator and the engine is: the resistance of the engine piston changes during shutdown. Specifically, there is a cylinder in the compression stroke for every half turn of the engine. During the compression stroke, the engine resistance is the smallest in the initial stage and the largest at the end of the compression stroke. Therefore, this process is a process in which the resistance continues to change.

[0004] CN118462449A discloses an engine stop position control method, electronic equipment, medium and hybrid vehicle, the method comprising: after receiving a signal from a control unit indicating that the engine stops fuel supply and ignition is successful, entering a reverse drag mode to control the engine to stop in reverse drag; receiving a position control instruction sent by a controller, and according to the position control instruction, controlling the engine to move from a first position to a preset stop position interval through a motor, the position control instruction is triggered by the controller in response to a stop success signal sent by the control unit, and the first position is the crankshaft position at the moment when the engine stops successfully. The engine stop position is precisely controlled by a motor controller so that the engine stops within a preset stop position interval after stopping. However, this technical solution is difficult to control the changes during the shutdown process by controlling the engine crankshaft to stop at a preset position, resulting in the inability of this solution to suppress the noise and vibration generated during the entire shutdown process.

[0005] CN110341686A discloses a range extender shutdown control method and vehicle, including determining whether the engine of the range extender meets the shutdown conditions. If the engine meets the shutdown conditions, the engine is first controlled to reduce the torque, and then the generator is controlled to reduce the speed to zero. During the generator torque control process, when it is detected that the torque of the range extender is zero, the torque slope of the generator is controlled so that the range extender passes the zero torque point smoothly. This technical solution is similar to CN118462449A, and only focuses on the control when the range extender speed is in the resonance zone, resulting in the solution being unable to effectively suppress the noise and vibration generated during the entire shutdown process.

[0006] CN112977391A discloses a control method for a range extender system, and the steps of stopping the range extender are as follows: T①, when the vehicle controller detects that the shutdown condition is met, the throttle voltage signal sent by the range extender controller to the engine controller is 0, and the speed signal request is stopped; T②, the generator controller maintains the power generation mode and adjusts the torque drop gradient according to the current operation state of the range extender, so that the speed of the range extender quickly reaches the idle target speed n0; T③, the range extender controller requests the generator controller to enter the 0 torque mode and requests the engine controller to perform idle control at the same time; T④, the range extender controller requests the engine controller to enter the idle mode and maintain the idle cumulative idle time t3 seconds; T⑤, the engine controller enters the idle mode and the cumulative idle time is less than t3 seconds, the range extender receives a new power demand instruction, and when the start-up condition is met, the range extender enters the power generation condition again; T⑥, the engine controller enters the idle mode and the cumulative idle time is greater than t3 seconds, and the range extender is turned off; T⑦, the range extender loses the speed signal and the shutdown is completed. This scheme reduces the frequent starting and stopping of the range extender by setting the cumulative idle time. However, the change in resistance during the shutdown process is not taken into account when the scheme is implemented, making it difficult to suppress the noise and vibration generated during the entire shutdown process.

[0007] CN118182440A discloses a range extender shutdown control method, system, vehicle controller and vehicle, the method includes: when the range extender shutdown demand is obtained, a shutdown command is sent to the engine controller of the range extender, and, according to a preset signal cycle, a speed command is regularly sent to the generator controller of the range extender, the speed command is used to instruct the generator controller to reduce the speed of the engine of the range extender to a target speed value, and the continuous target speed values ​​show a gradient downward trend; when the speed command is sent to the generator controller for the first time, the timing is started; when the timing duration is greater than or equal to the acquired speed request duration, a torque command is sent to the generator controller to complete the range extender shutdown control. This scheme achieves shutdown by adjusting the speed in stages, specifically judging whether to output reverse torque by timing duration, but the duration is not directly related to the piston resistance, and an additional calculation process is required to achieve a certain degree of connection. The overall scheme is complex and inaccurate, and the suppression of noise and vibration is limited.

[0008] Based on this, it is necessary to further provide a method for controlling the entire process of range extender shutdown, so as to minimize the abnormal noise caused by the relative speed change between the generator and the engine during the shutdown process. Summary of the invention

[0009] The purpose of the present invention is to provide a shutdown control method of a range extender, an electronic device and a range-extended vehicle in order to solve at least one of the above problems, so as to solve the problem of abnormal noise generated by the relative speed change between the generator and the engine during the shutdown process of the range extender in the prior art. The present invention controls the increase degree of the generator pressure stop torque (negative torque) by using the interval in which the crankshaft is located, thereby achieving a smoother increase in the total shutdown torque, thereby reducing the probability of abnormal noise occurring during the shutdown process.

[0010] The purpose of the present invention is achieved through the following technical solutions:

[0011] The first aspect of the present invention discloses a shutdown control method for a range extender.

[0012] According to the change of piston resistance in the compression stroke of the engine, the rotation angle of the crankshaft is divided into several angle intervals, including a low resistance interval, a uniform resistance interval and a high resistance interval arranged in sequence;

[0013] The method comprises the following steps:

[0014] The generator is in speed mode and maintains a constant speed, requesting the engine to cut off fuel;

[0015] When the rotation angle of the crankshaft is in the low resistance range, the generator switches to the torque mode and maintains a constant torque not less than 0, and the engine enters the shutdown process under friction resistance;

[0016] When the engine speed is lower than the speed threshold, the generator applies different negative torques when the crankshaft rotates to different angle ranges based on the change in resistance of the engine piston, thereby stopping the engine.

[0017] Preferably, the rotation angle of the crankshaft includes a low resistance interval, at least one uniform resistance interval and a high resistance interval arranged in sequence within the angle range of 0~180°, and the rotation angle of the crankshaft includes a low resistance interval, at least one uniform resistance interval and a high resistance interval arranged in sequence within the angle range of 180~360°.

[0018] Preferably, the rotation angle of the crankshaft is divided into eight angle intervals, wherein the angle interval of 0~180° includes a low resistance interval, two uniform resistance intervals and a high resistance interval arranged in sequence, and the angle interval of 180~360° includes a low resistance interval, two uniform resistance intervals and a high resistance interval arranged in sequence.

[0019] Preferably, it includes one or more of the following:

[0020] i) The constant speed is 700~900rpm;

[0021] ii) the constant torque is 0 N·m;

[0022] iii) The speed threshold is 500~650rpm.

[0023] Preferably, the negative torque applied by the generator is adjusted according to the size of the engine piston resistance, so that the total shutdown torque conforms to the set change trend.

[0024] Preferably, the negative torque applied by the generator in the low resistance range is greater than the negative torque applied in the uniform resistance range, and the negative torque applied in the uniform resistance range is greater than the negative torque applied in the high resistance range.

[0025] Preferably, the generator increases the amount of increase in negative torque in a low resistance range, and reduces the amount of increase in negative torque in a high resistance range.

[0026] The magnitude of the negative torque applied by the generator is adjusted according to the piston resistance. Since the piston resistance is small in the low resistance range, the generator can apply a negative torque with a larger increase. In the uniform resistance range, the piston resistance is uniform, so the negative torque applied by the generator can increase at a normal speed. In the high resistance range, the piston resistance itself is already large, so the negative torque applied by the generator has a smaller increase, which can make the total machine torque of the combination of the negative torque applied by the generator and the piston's own resistance smoother as a whole.

[0027] Preferably, the method described above is performed by the vehicle control unit (VCU) to determine whether to shut down, and the generator control unit (such as the generator controller) performs identification, detection and command control. That is, the method firstly performs a shutdown judgment by the VCU, and if the shutdown is decided, the steps of the method are entered; in the execution of each step, such as identification, detection, command control and other processes, they are all implemented by the generator control unit, which can effectively shorten the time delay, and thus can more accurately regulate the shutdown process, especially in the early stage of shutdown, when the crankshaft speed is still fast, the demand for low delay is more intense.

[0028] A second aspect of the present invention discloses an electronic device, which includes a memory and a processor. The memory stores a computer program, and the processor implements any of the above methods when executing the computer program.

[0029] A third aspect of the present invention discloses a computer-readable storage medium, wherein the storage medium stores a computer program, and when the computer program is executed by a processor, any of the above methods is implemented.

[0030] A fourth aspect of the present invention discloses an extended-range vehicle, comprising a vehicle controller, an engine and a generator, wherein the vehicle controller, the engine and the generator interact to execute any of the methods described above.

[0031] The working principle of the present invention is:

[0032] First, to ensure the timeliness of the engine crankshaft angle, after the VCU determines that shutdown is necessary, the main execution process should be controlled by the generator.

[0033] Subsequently, one rotation of the crankshaft is divided into several angular intervals, among which the piston resistance is the smallest in the starting interval of half a rotation of the crankshaft (low resistance interval, 0°, 180°, corresponding to the starting stage of the cylinder compression stroke), the piston resistance is the largest in the ending interval of half a rotation of the crankshaft (high resistance interval, 180°, 360°, corresponding to the ending stage of the cylinder compression stroke), and the piston resistance in the middle interval of half a rotation of the crankshaft (uniform resistance interval) is relatively uniform.

[0034] Then, the initial position of the shutdown process is controlled to ensure the consistency of the shutdown process: the generator is in speed mode, the speed is controlled to maintain a constant speed, and the engine is requested to cut off fuel and let the engine reverse; when it is recognized that the crankshaft angle is in the low resistance range, the generator switches to torque mode and maintains the torque constant as non-negative, and the engine relies on its own friction to reduce the speed and enters the shutdown process.

[0035] Finally, after the engine speed is lower than the speed threshold, the generator applies negative torque to stop the engine. The torque increases or decreases according to the interval position (i.e., piston resistance) to which the crankshaft rotates, so that the total shutdown torque composed of the negative torque applied by the generator and the piston resistance is smooth.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] The present invention relates the angular range of engine crankshaft rotation to the engine piston resistance, and can control the smooth change of the total shutdown torque by applying negative torque of different sizes (different torque rise / fall slopes) through the generator according to the crankshaft rotation angle position during the range extender shutdown process, thereby optimizing the shutdown process and reducing the probability of abnormal noise during the shutdown process.

[0038] In this method, one rotation of the crankshaft is divided into multiple intervals, and appropriate specified steps can be independently executed in different intervals to optimize the shutdown process. Compared with directly referring to the crankshaft angle signal for torque control, this method has higher reliability.

[0039] In this method, after the VCU determines that it is shut down, the main execution process is implemented by the generator, which can effectively reduce the communication delay. At the same time, the higher operating frequency of the generator can be used to make this method have a faster response speed.

[0040] The shutdown control method of the range extender can be applied to all types of extended-range vehicles and has broad market application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 A schematic diagram of the angle intervals divided by the crankshaft rotation angle in Example 1;

[0042] Figure 2 Schematic diagram of: a) original piston resistance and angle range, b) generator stop torque slope change, c) generator stop torque change, d) total stop torque in Example 1;

[0043] Figure 3 This is a flow chart of the shutdown control method in Example 1. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solutions and advantages of the present application clearer, the present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present invention. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0045] It should be noted that although the schematic diagram is divided into intervals and the flow chart shows a logical order, in some cases, the steps shown or described may be performed in a different order than the module division in the device or the order in the flow chart. The terms "first", "second", etc. in the specification, claims and the above drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0046] In the description of the present invention, it should be noted that if the terms "upper", "lower", "inside", "outside", etc. appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the drawings, or is the orientation or position relationship in which the product of the invention is usually placed when used. It is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0047] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein are only for the purpose of describing the embodiments of this application and are not intended to limit this application.

[0048] The range values ​​given in this scheme, such as: the constant speed is 700~900rpm, and any value within the range can be taken, such as 700rpm, 710rpm, 720rpm, 730rpm, 740rpm, 750rpm, 760rpm, 770rpm, 780rpm, 790rpm, 800rpm, 810rpm, 820rpm, 830rpm, 840rpm, 850rpm, 860rpm, 870rpm, 880rpm, 890rpm, 900rpm, etc. The speed threshold is 500~650rpm, and any value within the range can be taken, such as 500rpm, 510rpm, 520rpm, 530rpm, 540rpm, 550rpm, 560rpm, 570rpm, 580rpm, 590rpm, 600rpm, 610rpm, 620rpm, 630rpm, 640rpm, 650rpm, etc.

[0049] At present, since the engine and generator of the range extender are connected by a torsional damper, during the shutdown process, the relative speed between the engine and the generator will change between positive and negative, which will cause the spring of the torsional damper to be squeezed back and forth, causing abnormal noise.

[0050] The reason for the change in the relative speed between the generator and the engine is: the change in the resistance of the engine piston when the engine is stopped. Specifically, one cylinder is undergoing a compression stroke every half turn of the engine, and the resistance of the engine is the smallest at the beginning of the compression stroke and the largest at the end of the compression stroke.

[0051] In the prior art, although some studies have been conducted on suppressing the abnormal noise, most of the studies focus on how to control the engine crankshaft to stop at a preset position, and there are few studies on the changes during the shutdown process.

[0052] The applicant takes into account the high correlation between the rotation process of the crankshaft and the different stages of the compression stroke (piston resistance) in the engine cylinder. At the same time, the applicant also takes into account the drastic changes in the engine speed during the shutdown process. The accuracy of the crankshaft angle signal transmitted by the CAN signal is low, which leads to low reliability of directly referring to the crankshaft angle signal to control the shutdown torque. Therefore, the applicant proposes in this scheme to divide a crankshaft rotation into multiple intervals, perform specific steps in specific intervals, and then use the different rotation partition intervals of the crankshaft to control the increase of the generator compression shutdown torque, so that the total shutdown torque during the shutdown process increases more smoothly, and the shutdown process is optimized.

[0053] Example 1

[0054] A shutdown control method for a range extender, such as Figures 1 to 3 As shown,

[0055] According to the change of piston resistance in the compression stroke of the engine, the rotation angle of the crankshaft is divided into several angle intervals, including a low resistance interval, a uniform resistance interval and a high resistance interval arranged in sequence;

[0056] The method comprises the following steps:

[0057] The generator is in speed mode and maintains a constant speed, requesting the engine to cut off fuel;

[0058] When the rotation angle of the crankshaft is in the low resistance range, the generator switches to the torque mode and maintains a constant torque not less than 0, and the engine enters the shutdown process under friction resistance;

[0059] When the engine speed is lower than the speed threshold, the generator applies different negative torques when the crankshaft rotates to different angle ranges based on the change in resistance of the engine piston, thereby stopping the engine.

[0060] More specifically, in this embodiment:

[0061] like Figure 1 As shown, in this embodiment, the rotation angle of the crankshaft is equally divided into eight angle intervals, where:

[0062] Pointing directly upward is 0° (360°), pointing directly downward is 180°, pointing directly to the right is 90°, and pointing directly to the left is 270°, then: 0°~45° is interval ①, 45°~90° is interval ②, 90°~135° is interval ③, 135°~180° is interval ④, 180°~225° is interval ⑤, 225°~270° is interval ⑥, 270°~315° is interval ⑦, and 315°~360° is interval ⑧. It should be noted that Figure 1 The definition and division of the rotation angle in a specific direction is only for the convenience of understanding and explanation. In actual situations, it should be determined according to the specific rotation process of the engine.

[0063] Since at least one cylinder will be undergoing a compression stroke every half rotation of the engine (crankshaft), therefore: intervals ① and ⑤ are located exactly at the initial stage of the compression stroke of cylinder one and the initial stage of the power stroke of cylinder three, when the resistance of the piston is minimal; intervals ④ and ⑧ are located exactly at the final stage of the compression stroke of cylinder one and the final stage of the power stroke of cylinder three, when the resistance of the piston is maximum; intervals ②, ③, ⑥, and ⑦ are located in the middle of the compression stroke of cylinder one and the power stroke of cylinder three, when the resistance of the piston is relatively uniform.

[0064] In order to ensure the timeliness of the engine crankshaft angle, the range extender shutdown control method should be mainly executed by the generator after the VCU determines that the engine needs to be shut down. This can reduce communication delays and utilize the higher operating frequency of the generator (the control unit of the generator, specifically, the identification, judgment and command control through the generator indicated in this method are all implemented by the control unit of the generator (specifically, the generator controller is used in this embodiment)). When the method is executed, it can respond quickly to avoid missing the short time window that occurs during high-speed rotation (such as the step of identifying the crankshaft angle).

[0065] like Figure 3 As shown, the range extender shutdown control method in this embodiment is specifically implemented by the following steps:

[0066] 1) VCU determines and decides to shut down.

[0067] 2) The generator first adopts the speed mode to control and maintain the speed at 750rpm. At the same time, it requests the engine to cut off fuel supply and reverse the engine.

[0068] 3) When the generator controller recognizes that the crankshaft angle is in interval ① or interval ⑤, the generator switches to torque mode and controls to maintain its output torque at 0 N·m. At this time, the engine relies on the friction during its own movement to reduce the speed and enters the shutdown process.

[0069] 4) When the generator controller detects that the engine (crankshaft) speed is lower than 600rpm, the generator starts to execute negative torque to stop the engine, that is, the generator applies negative torque to the engine.

[0070] The rising / falling slope of the negative torque applied by the generator is adjusted accordingly according to the angle range of the crankshaft, so that the total shutdown torque formed by the negative torque applied by the generator and the piston's own resistance is smoother, thereby making the shutdown process smoother.

[0071] Specifically, Figure 2 As shown, the original piston resistance changes periodically with the change of the crankshaft rotation angle position when the engine is running (such as Figure 2 a), where, in interval ① to interval ③, the piston moves from the beginning of the compression stroke to the middle of the compression stroke, during which the piston resistance rises continuously and evenly from the low point. In interval ④, the piston is at the end of the compression stroke, and the piston resistance is at a high level and continues to rise. There is a period of rapid release of the piston resistance near the end of interval ④, that is, the compression stroke ends and enters the next compression stroke cycle. Since at least one cylinder is undergoing a compression stroke every half turn of the engine, the change process from interval ⑤ to interval ⑧ is consistent with that from interval ① to interval ④. The main difference lies in the different crankshaft rotation angles. The crankshaft rotation angles are 0°~180° in interval ① to interval ④, and 180°~360° in interval ⑤ to interval ⑧.

[0072] Based on the change of the original piston resistance, such as Figure 2 b) and 2c), the control method in this embodiment uses the following process to apply the pressing torque (negative torque):

[0073] When the generator controller recognizes that the crankshaft rotation angle is in interval ① or interval ⑤, the piston's own resistance is small at this time, and thus the negative torque used to stop the engine can be set to increase faster; when the generator controller recognizes that the crankshaft rotation angle is in interval ②, interval ③ or interval ⑥, interval ⑦, the piston's own resistance is relatively uniform at this time, and thus the negative torque used to stop the engine can be increased at the normal speed set conventionally; when the generator controller recognizes that the crankshaft rotation angle is in interval ④ or interval ⑧, the piston's own resistance is large at this time, and thus the negative torque used to stop the engine increases slower due to the setting.

[0074] Therefore, by applying a variable negative torque through the generator according to the different interval positions of the crankshaft rotation angle, the total stop torque formed by the combination of the pressure stop torque and the piston resistance can be made smoother, such as Figure 2 d) shows the combined resistance curve. This control method can make the resistance change during the range extender shutdown process smooth, basically changing according to a straight line with a fixed slope, with a certain linearity (the specific change trend can be set according to actual needs to adjust the negative torque applied by the generator accordingly), which can effectively alleviate the large positive and negative changes in the relative speed between the generator and the engine, thereby reducing the squeezing of the torsional damper to avoid abnormal noise. In addition, the main execution process of this control method is implemented and controlled by the generator, making full use of the low communication delay and high operation frequency of the generator. Therefore, this control method can confirm the situation change more timely and instruct to act, so that the application and change of negative torque can have higher timeliness, further reducing the change between the positive and negative relative speed of the generator and the engine.

[0075] In summary, this control method uses the relationship between the angle range of the engine crankshaft rotation and the engine piston resistance. During the range extender shutdown process, the generator applies negative torques of different sizes (different torque rise / fall slopes) according to the angle range of the crankshaft rotation to control the smooth change of the total shutdown torque, optimize the shutdown process, and reduce the probability of abnormal noise during the shutdown process. This control method can be used for all types and forms of extended-range vehicles.

[0076] Example 2

[0077] In this embodiment, the steps of the control method are consistent with those of Embodiment 1, with the main difference being that in step 2), when the generator adopts the speed mode, the speed is controlled and maintained at 800 rpm.

[0078] Example 3

[0079] In this embodiment, the steps of the control method are consistent with those of Embodiment 1, with the main difference being that in step 2), when the generator adopts the speed mode, the speed is controlled and maintained at 850 rpm.

[0080] Example 4

[0081] In this embodiment, the steps of the control method are consistent with those of Embodiment 1, with the main difference being that in step 2), when the generator adopts the speed mode, the speed is controlled and maintained at 900 rpm.

[0082] Example 5

[0083] In this embodiment, the steps of the control method are consistent with those of Embodiment 1, with the main difference being that in step 2), when the generator adopts the speed mode, the speed is controlled and maintained at 700 rpm.

[0084] Example 6

[0085] In this embodiment, the steps of the control method are consistent with those of Embodiment 1, with the main difference being that in step 2), when the generator adopts the speed mode, the speed is controlled and maintained at 750 rpm.

[0086] Example 7

[0087] In this embodiment, the steps of the control method are consistent with those of Embodiment 1, with the main difference being that in step 4), when the generator controller detects that the engine speed is lower than 650 rpm, the generator starts to execute negative torque to stop the engine.

[0088] Example 8

[0089] In this embodiment, the steps of the control method are consistent with those of Embodiment 1, with the main difference being that in step 4), when the generator controller detects that the engine speed is lower than 550 rpm, the generator starts to execute negative torque to stop the engine.

[0090] Example 9

[0091] In this embodiment, the steps of the control method are consistent with those of Embodiment 1, with the main difference being that in step 4), when the generator controller detects that the engine speed is lower than 500 rpm, the generator starts to execute negative torque to stop the engine.

[0092] Example 10

[0093] In this embodiment, the steps of the control method are consistent with those of Embodiment 1, with the main difference being that the rotation angle of the crankshaft is equally divided into twelve angle intervals.

[0094] Embodiment 11

[0095] In this embodiment, the steps of the control method are consistent with those of Embodiment 1, with the main difference being that the rotation angle of the crankshaft is equally divided into sixteen angle intervals.

[0096] Example 12

[0097] A range-extended vehicle comprises at least a vehicle control unit (VCU), an engine and a generator. The vehicle control unit can interact with the engine (engine controller) and the generator (generator controller), and a computer program for implementing the control method given in Example 1 is stored in the vehicle control unit.

[0098] Therefore, when the range extender of the extended-range vehicle is shut down, the VCU first determines to shut down, then the generator is adjusted to the speed mode and maintains the speed at 750rpm, and at the same time requests the engine to cut off fuel to make the engine reverse; the generator controller continuously monitors the crankshaft angle, and when the generator controller recognizes that the crankshaft angle is in interval ① or interval ⑤, it switches the generator to the torque mode and maintains the torque output at 0N·m, and realizes the speed reduction through the friction resistance of the engine itself; the generator controller also continuously monitors the engine speed, and when the engine speed is lower than 600rpm, the generator further starts to execute the process of negative torque to stop the engine, that is, the generator applies negative torque to the engine to stop the generator. In this process, the negative torque is adaptively adjusted according to the angle range of the crankshaft rotation angle to make the total shutdown resistance smooth; finally, the shutdown of the range extender is completed.

[0099] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A shutdown control method for a range extender, characterized in that: According to the change of piston resistance in the compression stroke of the engine, the rotation angle of the crankshaft is divided into several angle intervals, including a low resistance interval, a uniform resistance interval and a high resistance interval arranged in sequence; The method comprises the following steps: The generator is in speed mode and maintains a constant speed, requesting the engine to cut off fuel; When the rotation angle of the crankshaft is in the low resistance range, the generator switches to the torque mode and maintains a constant torque not less than 0, and the engine enters the shutdown process under friction resistance; When the engine speed is lower than the speed threshold, the generator applies different negative torques when the crankshaft rotates to different angle ranges based on the change in resistance of the engine piston, thereby stopping the engine.

2. A shutdown control method for a range extender according to claim 1, characterized in that: The rotation angle of the crankshaft includes a low resistance interval, at least one uniform resistance interval and a high resistance interval arranged in sequence within the angle range of 0 to 180°, and the rotation angle of the crankshaft includes a low resistance interval, at least one uniform resistance interval and a high resistance interval arranged in sequence within the angle range of 180 to 360°.

3. A shutdown control method for a range extender according to claim 2, characterized in that: The rotation angle of the crankshaft is divided into eight angle intervals, wherein the angle interval of 0 to 180° includes a low resistance interval, two uniform resistance intervals and a high resistance interval arranged in sequence, and the angle interval of 180 to 360° includes a low resistance interval, two uniform resistance intervals and a high resistance interval arranged in sequence.

4. The shutdown control method of a range extender according to claim 1, characterized in that: Includes one or more of the following: i) The constant speed is 700-900 rpm; ii) the constant torque is 0 N·m; iii) The rotation speed threshold is 500-650 rpm.

5. The shutdown control method of a range extender according to claim 1, characterized in that: The negative torque applied by the generator is adjusted according to the size of the engine piston resistance, so that the total shutdown torque conforms to the set change trend.

6. A shutdown control method for a range extender according to claim 5, characterized in that: The negative torque applied by the generator in the low resistance range is greater than the negative torque applied in the uniform resistance range, and the negative torque applied in the uniform resistance range is greater than the negative torque applied in the high resistance range.

7. A shutdown control method for a range extender according to claim 5, characterized in that: The generator increases the amount of negative torque increase in a low resistance range, and reduces the amount of negative torque increase in a high resistance range.

8. The shutdown control method of a range extender according to claim 1, characterized in that: In the method, the vehicle controller determines whether to shut down, and the control unit of the generator performs identification, detection and command control.

9. An electronic device, characterized in that: The electronic device comprises a memory and a processor, wherein the memory stores a computer program, and the processor implements the method according to any one of claims 1 to 8 when executing the computer program.

10. An extended-range vehicle, characterized in that: The vehicle controller, the engine and the generator are included, wherein the vehicle controller, the engine and the generator interact with each other to execute the method according to any one of claims 1 to 8.

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