Control method for engine stop position and device therefor, vehicle

Abstract

The application discloses a control method and device of an engine stop position and a vehicle, the control method is applied to the vehicle, and the control method comprises the following steps: obtaining an initial target stop position of an engine; in the start-stop process of the engine, evaluating the target stop position according to an index parameter to obtain an evaluation result; and correcting the target stop position of the engine according to the evaluation result. The target stop position is accurately kept in a suitable position in a correction mode on the basis of the initial target stop position, and the accuracy of the target stop position is improved.

Description

Technical Field

[0001] This application relates to the field of transportation vehicles, and more specifically to a method and apparatus for controlling the engine stop position, and a vehicle. Background Technology

[0002] Hybrid vehicles frequently start and stop their engines during operation. Due to the engine's structure, the resistance to restarting varies depending on the engine's stopping position. Currently, in the engine start-stop control architecture of hybrid systems, a generator or drive motor is connected to the engine. The motor can start the engine or control its stopping position when stopping. The motor's torque is controlled by the vehicle control unit (VCU). The VCU obtains the actual crankshaft position of the engine through the engine control unit (ECU) and controls the engine to stop at the target stopping position. Specifically, the stopping control principle is as follows: When the engine needs to be stopped during hybrid vehicle operation, the VCU reads the target stopping position from memory and adjusts the motor torque to stop the engine at the target stopping position. Existing methods for determining the target stopping position are obtained through a combination of theoretical design and calibration; however, the target stopping position determined by this method is not accurate enough. Summary of the Invention

[0003] This application is made to address at least one of the aforementioned problems. According to a first aspect of this application, a method for controlling the engine stop position is provided, the method comprising: acquiring an initial target stop position of the engine; evaluating the target stop position based on index parameters during the engine start-stop process to obtain an evaluation result; and correcting the target stop position of the engine based on the evaluation result.

[0004] In one embodiment of this application, the step of evaluating the target shutdown position according to index parameters and obtaining an evaluation result during the start-stop process of the engine includes: when starting the engine, evaluating the target shutdown position used when the engine was last stopped according to the index parameters, and obtaining the evaluation result of the target shutdown position used when the engine was last stopped.

[0005] In one embodiment of this application, the index parameter is the index parameter of the NVH index.

[0006] In one embodiment of this application, the index parameter is acceleration in the NVH index.

[0007] In one embodiment of this application, the acceleration includes at least one of the longitudinal acceleration and the vertical acceleration of the vehicle in which the engine is located.

[0008] In one embodiment of this application, the acceleration includes the vehicle's longitudinal acceleration and vertical acceleration; the step of evaluating the target stopping position used when the engine was last stopped based on the index parameters when starting the engine, and obtaining the evaluation result of the target stopping position used when the engine was last stopped, includes: when starting the engine, determining the evaluation result of the target stopping position used when the engine was last stopped based on a preset weighting coefficient, the vehicle's longitudinal acceleration and vertical acceleration.

[0009] In one embodiment of this application, determining the evaluation result of the target stopping position used when the engine was last stopped, based on a preset weighting coefficient, the vehicle's longitudinal acceleration, and its vertical acceleration, includes: calculating the evaluation result NVHEm of the target stopping position used when the engine was last stopped using the following formula when starting the engine:

[0010]

[0011] Wherein, a represents the preset weighting coefficient; Ax represents the acceleration of the vehicle in the front-to-back direction; Ay represents the acceleration of the vehicle in the vertical direction; Ax0 represents the average value of Ax within a preset time period before engine start; and Ay0 represents the average value of Ay within a preset time period before engine start.

[0012] In one embodiment of this application, the longitudinal acceleration Ax of the vehicle is: the acceleration after filtering the original longitudinal acceleration of the vehicle; wherein the original longitudinal acceleration of the vehicle is obtained from the vehicle's electronic stability system; and / or, the vertical acceleration Ay of the vehicle is: the acceleration after filtering the original vertical acceleration of the vehicle; wherein the original vertical acceleration of the vehicle is obtained from the vehicle's electronic stability system.

[0013] In one embodiment of this application, the index parameter is the noise in the NVH index.

[0014] In one embodiment of this application, the index parameter is the starting resistance of the engine during startup.

[0015] In one embodiment of this application, correcting the target stopping position of the engine based on the evaluation result includes: dynamically correcting the target stopping position of the engine based on the evaluation result.

[0016] In one embodiment of this application, the step of dynamically correcting the target stopping position of the engine based on the evaluation result includes: when the evaluation result fails to meet the preset requirements at least once, controlling the target stopping position to enter the correction phase.

[0017] In one embodiment of this application, the step of dynamically correcting the target stopping position of the engine based on the evaluation result further includes: after controlling the target stopping position to enter the correction stage, sequentially taking each of the preset plurality of correction stopping positions as the target stopping position of the correction stage, obtaining the evaluation result of each correction stopping position in the correction stage; selecting the optimal evaluation result from all the evaluation results of the correction stopping positions in the correction stage, and taking the correction stopping position corresponding to the optimal evaluation result as the target stopping position after the correction stage ends.

[0018] In one embodiment of this application, the plurality of corrective stopping positions are located within a correction interval; wherein, the correction interval is: an interval determined by a preset offset based on the initial target stopping position.

[0019] In one embodiment of this application, the step of dynamically correcting the target stopping position of the engine based on the evaluation result includes: when the evaluation result meets the preset requirements, controlling the target stopping position to enter a holding phase.

[0020] In one embodiment of this application, the step of evaluating the target stopping position based on index parameters and obtaining the evaluation result during the start-stop process of the engine further includes: determining the crankshaft position of the engine based at least on the mechanical angle of the motor of the vehicle in which the engine is located.

[0021] In one embodiment of this application, determining the crankshaft position of the engine based at least on the mechanical angle of the motor of the vehicle in which the engine is located includes: determining the crankshaft position of the engine based on the mechanical angle of the motor of the vehicle, the phase difference between the motor and the engine, and the speed ratio.

[0022] In one embodiment of this application, determining the crankshaft position of the engine based on the mechanical angle of the vehicle's motor, the phase difference between the motor and the engine, and the speed ratio includes: determining the crankshaft position CurPos of the engine using the following formula:

[0023] CurPos=f((CurMotorPos-MotorPosZero) / R)

[0024] Where CurMotorPos represents the mechanical angle of the motor; MotorPosZero represents the phase difference between the motor and the engine; R represents the speed ratio between the motor and the engine; and f() represents the filtering function.

[0025] In one embodiment of this application, the step of evaluating the target stopping position based on index parameters and obtaining the evaluation result during the start-stop process of the engine further includes: controlling the engine to stop at the target stopping position based on the crankshaft position of the engine.

[0026] According to a second aspect of this application, a control device for an engine stop position is also provided. The control device includes a storage medium and a processor. The storage medium stores a computer program executed by the processor. When the computer program is executed by the processor, it causes the processor to perform any of the above-described engine stop position control methods.

[0027] According to a third aspect of this application, a vehicle is also provided, the vehicle comprising: an engine, an electric motor, and a control device for any of the above-described engine stop positions.

[0028] According to the engine stop position control method, device, and vehicle provided in the embodiments of this application, after obtaining the initial target stop position of the engine, during the engine start-stop process, the target stop position is evaluated based on index parameters to obtain an evaluation result, and the target stop position of the engine is corrected based on the evaluation result, so that the target stop position is accurately maintained in a suitable position based on the initial target stop position, thereby improving the accuracy of the target stop position. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a flowchart illustrating a method for controlling the engine stop position according to an embodiment of the present invention;

[0031] Figure 2 This is a schematic diagram of a vehicle engine shutdown control architecture according to an embodiment of the present invention;

[0032] Figure 3 This is a flowchart illustrating the control of engine shutdown according to an embodiment of the present invention;

[0033] Figure 4This is a flowchart illustrating a method for controlling the engine stop position according to another embodiment of the present invention;

[0034] Figure 5 This is a schematic block diagram of a control device for the engine stop position according to an embodiment of the present invention. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of the present invention more apparent, exemplary embodiments according to the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are merely a part of the embodiments of the present invention, and not all of the embodiments of the present invention. It should be understood that the present invention is not limited to the exemplary embodiments described herein. Based on the embodiments of the present invention described herein, all other embodiments obtained by those skilled in the art without inventive effort should fall within the protection scope of the present invention.

[0036] In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention can be practiced without one or more of these details. In other instances, certain technical features well-known in the art have not been described in order to avoid obscuring the invention.

[0037] It should be understood that the invention can be embodied in various forms and should not be construed as being limited to the embodiments set forth herein. Rather, providing these embodiments will make the disclosure thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0038] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. When used herein, the singular forms “a,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “compose” and / or “comprising,” when used in this specification, confirm the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups. When used herein, the term “and / or” includes any and all combinations of the associated listed items.

[0039] To fully understand this invention, a detailed structure will be presented in the following description to illustrate the technical solution proposed by this invention. Optional embodiments of the invention are described in detail below; however, in addition to these detailed descriptions, the invention may have other embodiments.

[0040] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0041] First, let me introduce the application scenario of the engine stop position control method illustrated in this application. This control method is applied to a vehicle, specifically in the process of controlling the engine stop position.

[0042] refer to Figure 1 This application provides a method for controlling the engine stop position, the method comprising:

[0043] Step 1: Obtain the initial target stopping position of the engine;

[0044] Step 2: During the engine start-stop process, assess the target stopping position based on the indicator parameters and obtain the assessment results;

[0045] Step 3: Based on the evaluation results, adjust the target shutdown position of the engine.

[0046] In the above scheme, after obtaining the initial target stopping position of the engine, during the engine start-stop process, the target stopping position is evaluated based on the index parameters to obtain the evaluation result. The target stopping position of the engine is then corrected based on the evaluation result. This correction method ensures that the target stopping position is accurately maintained at a suitable location based on the initial target stopping position, thereby improving the accuracy of the target stopping position. The above method will be described in detail below with reference to the accompanying drawings.

[0047] First, refer to Figure 1 The initial target stopping position of the engine is obtained. The initial target stopping position of the engine can be obtained by combining theoretical values ​​and calibration values, and can be obtained before the engine leaves the factory.

[0048] Next, continue to refer to Figure 1 During engine start-stop, the target stopping position is evaluated based on indicator parameters to obtain the evaluation result. There are several methods for evaluating the target stopping position and obtaining the evaluation result during engine start-stop. Several methods are illustrated below.

[0049] For example, during engine start-stop, when evaluating the target stopping position based on indicator parameters and obtaining the evaluation result, the following method can be used: When starting the engine, evaluate the target stopping position used during the last engine shutdown based on the indicator parameters, and obtain the evaluation result of the target stopping position used during the last engine shutdown. That is, when starting the engine, evaluate the target stopping position used during the last engine shutdown to determine whether the target stopping position used during the last engine shutdown was accurate and appropriate. There are several ways to evaluate the target stopping position used during the last engine shutdown and obtain the evaluation result; the following are examples illustrating several evaluation methods.

[0050] The aforementioned indicators and parameters can directly or indirectly reflect the resistance encountered when restarting the engine after it has been stopped at different positions. These can be any type of indicator or parameter used to evaluate the vehicle in which the engine is located. Some examples are described below.

[0051] For example, during engine startup, when evaluating the target stopping position used when the engine was last stopped, the target stopping position used when the engine was last stopped can be evaluated based on the parameter parameters of the set indicators of the vehicle where the engine is located, so as to obtain the evaluation result of the target stopping position used when the engine was last stopped.

[0052] For example, the indicator parameter can be an NVH indicator parameter. NVH indicators reflect the noise, vibration, and acoustic roughness of a vehicle. It is important to note that the specific indicator parameter is related to the type of indicator used. An indicator type is often evaluated using multiple parameters. For example, when the indicator is an NVH indicator, the indicator parameter can be acceleration from the NVH indicator. It should be noted that the indicator parameter reflecting the NVH indicator is not limited to acceleration parameters; other types of indicator parameters can also be used. For example, in some embodiments, noise parameters can also be used as NVH indicator parameters.

[0053] For example, when the index parameter is the acceleration of the NVH index, the acceleration includes at least one of the longitudinal acceleration and vertical acceleration of the vehicle where the engine is located. For instance, only the longitudinal acceleration of the vehicle can be used as the index parameter of the set index in the evaluation process. Of course, only the vertical acceleration of the vehicle can be used as the index parameter of the set index in the evaluation process. In some embodiments, both the longitudinal acceleration and the vertical acceleration of the vehicle can be used together as the index parameter of the set index in the evaluation process.

[0054] When a vehicle is driving normally, its acceleration in the longitudinal and vertical directions tends to be stable with minimal fluctuations. If there is a significant engine start-up jerk, the vehicle's acceleration in these directions will fluctuate considerably. The greater the jerk and the greater the fluctuation, the worse the NVH performance. Therefore, in some embodiments of this application, the fluctuation of vehicle acceleration in the longitudinal and vertical directions can be used to evaluate NVH performance. The determination of the preset weighting coefficient is related to whether the acceleration (i.e., the jerk) is more pronounced in the longitudinal or vertical direction when the jerk occurs. If the jerk has a greater impact on the longitudinal acceleration, then the preset weighting coefficient will be set to a larger value for the longitudinal acceleration.

[0055] For example, acceleration includes the vehicle's longitudinal acceleration and vertical acceleration. When starting the engine, based on the index parameters, the target stopping position used during the last engine shutdown is evaluated to obtain the evaluation result of the target stopping position used during the last engine shutdown. This evaluation result can be determined during engine startup based on preset weighting coefficients, the vehicle's longitudinal acceleration, and the vertical acceleration. The preset weighting coefficients represent the magnitude of the influence of each acceleration in the longitudinal and vertical directions on the evaluation result. For example, the preset weighting coefficients can be between 0 and 1. The preset weighting coefficients can represent the influence of the longitudinal acceleration on the evaluation result, and (1 - preset weighting coefficient) can represent the influence of the vertical acceleration on the evaluation result.

[0056] For example, when starting the engine, based on preset weighting coefficients, the vehicle's longitudinal acceleration, and vertical acceleration, to determine the evaluation result of the target stopping position used during the last engine shutdown, the evaluation result NVHEm of the target stopping position used during the last engine shutdown can be calculated using the following formula:

[0057]

[0058] Where 'a' represents a preset weighting coefficient; Ax represents the vehicle's acceleration in the longitudinal direction; Ay represents the vehicle's acceleration in the vertical direction; Ax0 represents the average value of Ax within a preset time period before engine start; and Ay0 represents the average value of Ay within a preset time period before engine start. This preset time period can be a specific time interval such as 50ms.

[0059] For example, the vehicle's longitudinal acceleration Ax can be: the acceleration after filtering the original longitudinal acceleration; wherein the original longitudinal acceleration is obtained from the vehicle's electronic stability system; and / or, the vehicle's vertical acceleration Ay can be: the acceleration after filtering the original vertical acceleration; wherein the original vertical acceleration is obtained from the vehicle's electronic stability system. Filtering the original acceleration obtained from the electronic stability system eliminates interference and improves the accuracy of the evaluation results.

[0060] It should be understood that the selection of the parameter for the set index is not limited to the NVH indexes shown above; other indexes may also be used. For example, in some embodiments, the set index may also be an engine index, where the parameter can be the engine's starting resistance during startup. The target stopping position used during the last engine shutdown is evaluated by collecting the engine's starting resistance at each startup, thus obtaining the evaluation result. For example, for a vehicle, there is a correlation between the engine's starting resistance and the overall NVH performance of the vehicle. A higher engine starting resistance results in a worse NVH index, while a lower starting resistance results in a better NVH index. In some embodiments of this application, the NVH index and the engine's starting resistance can be used together as the basis for evaluating the target stopping position, improving the accuracy of the evaluation results.

[0061] In some embodiments of this application, to reduce vehicle vibration and noise during engine startup and improve NVH (Noise, Vibration, and Harshness), the engine is controlled to stop at a target stopping position when the engine stops. This target stopping position can be dynamically corrected. The corrected target stopping position has lower starting resistance, improving the accuracy of the target stopping position, minimizing or reducing the starting resistance when the engine stops at the corrected target stopping position, or ensuring that the starting resistance corresponding to the engine stopping at the modified target stopping position has a small or acceptable impact on the vehicle's NVH performance during startup.

[0062] Existing methods using a fixed value as the target stopping position fail to address the following issues: ① Manufacturing tolerances result in variations in the minimum resistance position for engine starting, leading to different target stopping positions for each engine; ② Engines mounted on different vehicles may have inconsistent installation angles, affecting the target stopping position; ③ Wear and tear during engine operation can also cause variations in the target stopping position. In contrast to existing methods using a fixed value, this application considers that the target stopping position is not a fixed value due to manufacturing variations, installation angles, wear, etc. It employs a dynamic correction method to obtain the target stopping position. This dynamically corrected target stopping position adapts to manufacturing tolerances, aging wear, installation angles, etc., ensuring the engine always stops at the appropriate target stopping position, resulting in consistently good NVH performance for the entire vehicle during startup.

[0063] Next, refer to Figure 1Based on the evaluation results, the target engine stop position is corrected. Various methods can be used for this correction. For example, when correcting the engine's target stop position based on the evaluation results, it can be dynamically corrected. This allows the target stop position to be accurately maintained at the position of minimum starting resistance, improving its accuracy. Specifically, after the engine leaves the factory and is applied to the vehicle, during the engine's start-stop process, the initially acquired target stop position can be dynamically corrected to accommodate inaccuracies caused by factors such as, but not limited to, manufacturing tolerances, aging wear, and installation angles. This dynamic correction ensures the target stop position is accurately maintained at the position of minimum starting resistance, further improving its accuracy.

[0064] In the process of dynamically correcting the target stopping position of the engine, several methods can be used. Several methods are illustrated below.

[0065] For example, when dynamically correcting the target stopping position of the engine based on the evaluation results, the target stopping position can be controlled to enter the correction phase if the evaluation results fail to meet the preset requirements at least once, thereby triggering the correction of the target stopping position. These preset requirements are determined based on the evaluation method and reflect the accuracy of the target stopping position.

[0066] For example, to prevent misjudgment caused by triggering correction of the target stopping position based on a single evaluation result not meeting the preset requirements, this application, in some embodiments, can control the target stopping position to enter the correction stage only when at least two consecutive evaluation results do not meet the preset requirements. For example, the target stopping position can be controlled to enter the correction stage when the evaluation results fail to meet the preset requirements any number of times, such as two, three, four, eight, or ten times consecutively.

[0067] If the evaluation result of the target shutdown position used during the last engine shutdown does not meet the preset requirements, it indicates that the target shutdown position used during the last engine shutdown may be inaccurate. After the target shutdown position enters the correction phase, there are various ways to correct the target shutdown position. Several methods are illustrated below.

[0068] For example, in the process of dynamically correcting the engine's target stopping position based on the evaluation results, after controlling the target stopping position to enter the correction phase, each of the preset multiple correction stopping positions can be sequentially used as the target stopping position for the correction phase, and the evaluation result of each correction stopping position in the correction phase can be obtained. Then, from all the evaluation results of the correction stopping positions in the correction phase, the optimal evaluation result is selected, and the correction stopping position corresponding to the optimal evaluation result is used as the target stopping position after the correction phase ends. That is, from all the evaluation results of the correction stopping positions, the correction stopping position corresponding to the optimal evaluation result is selected as the target stopping position after the current correction phase ends, and the corrected target stopping position is used as the target stopping position in the subsequent holding phase.

[0069] There are various methods for determining the correction stop positions. For example, multiple preset correction stop positions can be located within a correction interval, which is an interval determined by a preset offset based on the initial target stop position. For instance, when the initial target stop position is 30°, the preset offset can be ±5°, and the correction interval can be 25° to 35°. When the correction step value for the target stop position is 1°, the correction stop positions included within this correction interval can include 11 correction stop positions: 25°, 26°, 27°, 28°, 29°, 30°, 31°, 32°, 33°, 34°, and 35°.

[0070] When sequentially using each of the multiple correction stop positions as the target stop position for this correction phase and obtaining the evaluation result for each correction stop position, during the correction phase, all correction stop positions are temporarily used as the target stop positions for the correction phase. After at least one stop and start, the evaluation result for each correction stop position in the correction phase can be obtained. Then, the optimal evaluation result among all the evaluation results of the correction target positions is selected, and the optimal evaluation result is used as the target stop position determined after the correction is completed. In the subsequent holding phase, the newly determined target stop position is used to control the engine to stop.

[0071] For example, during the process of dynamically correcting the engine's target shutdown position based on the evaluation results, when the evaluation results meet preset requirements, the target shutdown position is controlled to enter a holding phase. If the evaluation result of the target shutdown position used during the last engine shutdown meets the preset requirements, it indicates that the target shutdown position used during the last engine shutdown was relatively accurate, and no correction is needed; the target shutdown position remains unchanged. Alternatively, during the process of dynamically correcting the engine's target shutdown position based on the evaluation results, if the evaluation result of the target shutdown position used during the last engine shutdown meets the preset requirements, the target shutdown position can be controlled to enter a holding phase, maintaining the current target shutdown position unchanged. When the engine is shut down again, the current target shutdown position will continue to be used.

[0072] For example, during engine start-stop, when dynamically correcting the engine's target stop position, the target stop position used during the last engine stop can be evaluated when starting the engine, yielding an evaluation result. Then, based on the evaluation result of the target stop position used during the last engine stop and preset requirements, it is determined whether to correct the target stop position. For example, if the evaluation result fails to meet the preset requirements at least once, the target stop position is controlled to enter a correction phase to trigger correction. These preset requirements are determined based on the evaluation method and reflect the accuracy of the target stop position.

[0073] If the evaluation result of the target shutdown position used during the last engine shutdown meets the preset requirements, it indicates that the target shutdown position used during the last engine shutdown was relatively accurate, and no correction is needed; the target shutdown position remains unchanged. For example, during engine start-stop, when dynamically correcting the engine's target shutdown position, if the evaluation result of the target shutdown position used during the last engine shutdown meets the preset requirements, the target shutdown position can be controlled to enter a holding phase, maintaining the current target shutdown position unchanged. When the engine is shut down again, the current target shutdown position will continue to be used.

[0074] If the evaluation result of the target shutdown position used during the last engine shutdown does not meet the preset requirements, it indicates that the target shutdown position used during the last engine shutdown may be inaccurate. In a more preferred embodiment, when controlling the target shutdown position to enter the correction stage at least once the evaluation result does not meet the preset requirements, the target shutdown position can be controlled to enter the correction stage only when the evaluation result does not meet the preset requirements at least twice consecutively. To prevent misjudgment caused by triggering the correction of the target shutdown position due to a single evaluation result not meeting the preset requirements, in some embodiments of this application, the target shutdown position can be controlled to enter the correction stage only when the evaluation result does not meet the preset requirements at least twice consecutively. For example, the target shutdown position can be controlled to enter the correction stage when the evaluation result does not meet the preset requirements any number of times, such as two, three, four, eight, or ten consecutive times.

[0075] For example, during the engine start-stop process, in the process of dynamically correcting the engine's target stop position, after controlling the target stop position to enter the correction phase, each of the preset correction stop positions is sequentially used as the target stop position for the correction phase, and the evaluation result of each correction stop position in the correction phase is obtained. Then, from all the evaluation results of the correction stop positions, the optimal evaluation result is selected, and the correction stop position corresponding to the optimal evaluation result is used as the target stop position after the correction phase ends. That is, from all the evaluation results of the correction stop positions, the correction stop position corresponding to the optimal evaluation result is selected as the target stop position after the end of this correction phase, and the corrected target stop position is used as the target stop position in the subsequent holding phase.

[0076] For example, during engine startup, when evaluating the target stopping position used during the last engine shutdown, the evaluation can be performed based on the vehicle's set index parameters to obtain the evaluation result of the target stopping position used during the last engine shutdown. This set index can directly or indirectly reflect the resistance magnitude when the engine restarts after different stopping positions, and can be any type of index used to evaluate the vehicle. For example, this set index can be an NVH index. NVH indexes reflect the noise, vibration, and acoustic roughness of a vehicle. It should be noted that the index parameters are specifically related to the type of set index used. An index type is often evaluated through multiple parameters. For example, when the set index is an NVH index, the index parameter can be acceleration from the NVH index. It should be noted that the index parameters reflecting the NVH index are not limited to acceleration parameters; other types of index parameters can also be used. For example, in some embodiments, noise parameters can also be used as NVH index parameters.

[0077] In some embodiments of this application, to reduce vehicle vibration and noise during engine startup and improve NVH (Noise, Vibration, and Harshness), the engine is controlled to stop at a target stopping position when the engine stops. This target stopping position can be dynamically corrected. The corrected target stopping position has lower starting resistance, improving the accuracy of the target stopping position, minimizing or reducing the starting resistance when the engine stops at the corrected target stopping position, or ensuring that the starting resistance corresponding to the engine stopping at the modified target stopping position has a small or acceptable impact on the vehicle's NVH performance during startup.

[0078] Existing methods using a fixed value as the target stopping position fail to address the following issues: ① Manufacturing tolerances result in variations in the minimum resistance position for engine starting, leading to different target stopping positions for each engine; ② Engines mounted on different vehicles may have inconsistent installation angles, affecting the target stopping position; ③ Wear and tear during engine operation can also cause variations in the target stopping position. In contrast to existing methods using a fixed value, this application considers that the target stopping position is not a fixed value due to manufacturing variations, installation angles, wear, etc. It employs a dynamic correction method to obtain the target stopping position. This dynamically corrected target stopping position adapts to manufacturing tolerances, aging wear, installation angles, etc., ensuring the engine always stops at the appropriate target stopping position, resulting in consistently good NVH performance for the entire vehicle during startup.

[0079] Additionally, in some embodiments, references Figure 2 and Figure 3 During engine start-stop, the target stopping position is evaluated based on indicator parameters to obtain the evaluation result. This may also include determining the engine crankshaft position based at least on the mechanical angle of the electric motor in the vehicle. In other words, the engine crankshaft position needs to be determined during engine start-stop. However, unlike existing technologies that directly obtain the current crankshaft position from the engine controller, this process also obtains the current mechanical angle of the electric motor from the electric motor controller and determines the engine crankshaft position based at least on this angle. This reduces the step value representing the engine crankshaft position, thereby improving the accuracy of the determined crankshaft position.

[0080] When determining the crankshaft position of an engine based at least on the mechanical angles of the vehicle's electric motor, various methods can be employed. For example, when determining the crankshaft position based at least on the mechanical angles of the vehicle's electric motor, the crankshaft position can be determined based on the mechanical angles of the vehicle's electric motor, the phase difference between the motor and the engine, and the speed ratio.

[0081] In some embodiments, when determining the crankshaft position of the engine based on the mechanical angle of the vehicle's motor, the phase difference between the motor and the engine, and the speed ratio, the crankshaft position CurPos of the engine can be determined using the following formula:

[0082] CurPos=f((CurMotorPos-MotorPosZero) / R)

[0083] Where CurMotorPos represents the mechanical angle of the motor; MotorPosZero represents the phase difference between the motor and the engine; R represents the speed ratio between the motor and the engine; and f() represents the filter function.

[0084] In some embodiments, the cutoff frequency in the filter function can be positively correlated with the motor speed. The higher the motor speed, the higher the cutoff frequency in the filter function; conversely, the lower the motor speed, the lower the cutoff frequency. This allows for dynamic adjustment of the cutoff frequency in the filter function. For example, the filter function f() can be, but is not limited to, a first-order filter function, a second-order filter function, etc.

[0085] In some embodiments, reference Figure 2 and Figure 3 During engine start-stop, the target stopping position is evaluated based on indicator parameters, and the evaluation result is obtained. This may also include controlling the engine to stop at the target stopping position using any of the crankshaft positions determined as shown above. That is, the engine crankshaft position also needs to be determined during engine shutdown. The crankshaft position can be determined using any of the methods shown above to ensure the engine stops as close to the target stopping position as possible, thus controlling the engine to stop accurately at the target stopping position.

[0086] In existing technologies, the crankshaft position of the engine is mainly obtained through the engine controller to determine the actual position accuracy of the crankshaft, thereby determining the engine's time-stop position. However, the actual position of the engine crankshaft is related to the number of crankshaft teeth. For example, when the number of crankshaft teeth is 58, the resolution (step value) of the engine stop position is only 6 degrees, meaning the highest control accuracy is only 6 degrees, which is poor. To reduce vehicle vibration and noise during engine start-up and improve NVH, this application further improves the control accuracy of the engine stop position in some embodiments, that is, reducing the error between the actual stop position and the target stop position. In some embodiments, this application obtains the actual crankshaft position of the engine by processing the current crankshaft teeth and the motor mechanical angle. A resolver sensor is installed in the motor to measure the mechanical angle of the motor rotor, and the motor rotor is always connected to the crankshaft with a fixed speed ratio between them, so that the mechanical angle of the rotor and the angle of the crankshaft have a corresponding relationship, thereby determining the actual position of the engine crankshaft through the mechanical angle of the motor, and thus controlling the actual stop position of the engine. Because the motor has a resolver sensor with high accuracy (far exceeding 6 degrees), the processed actual crankshaft position of the engine is highly accurate. That is, the crankshaft position calculated by combining the engine's crankshaft position with the motor's mechanical angle is more precise, resulting in higher control accuracy. This allows for higher control precision at the actual stopping position of the engine, facilitating accurate stopping at the target stopping position and reducing errors.

[0087] The following is combined Figure 2 , Figure 3 and Figure 4 This paper exemplifies a method for controlling the target stopping position of an engine. First, it should be noted that VCU represents the vehicle control unit; ESP represents the vehicle's electronic stability program; EEROM represents electrically erasable memory, a storage medium used to store the target stopping position; MCU represents the motor controller; and ECU represents the engine controller.

[0088] refer to Figure 2 , Figure 3 and Figure 4 Step 1: Obtain the theoretical target stopping position of the engine based on the design theoretical parameters, which can be obtained offline;

[0089] Step 2: Based on the theoretical target stopping position, calibrate the actual vehicle to obtain the initial target stopping position. For example, the stopping position corresponding to the best NVH performance during engine start-up can be used as the initial target stopping position StopPosEp, and the target stopping position is stored in the VCU's EEROM.

[0090] Step 3: After the VCU is powered on, it reads the target stop position StopPosEp from the EEROM;

[0091] TarStopPos=StopPosEp

[0092] TarStopPos represents the target shutdown position used when controlling engine shutdown.

[0093] Step 4: Obtain the current crankshaft position information CurEngPos from the engine ECU; obtain the current mechanical angle of the motor CurMotorPos from the motor MCU. Calculate the current crankshaft position CurPos of the engine in real time.

[0094] CurPos=f((CurMotorPos-MotorPosZero) / R)

[0095] Where: CurMotorPos represents the current mechanical angle of the motor; MotorPosZero represents the phase difference between the motor and the engine, which is the mechanical angle of the motor when CurEngPos is 0; R is the speed ratio from the motor to the engine; f() is a first-order filter function, and the cutoff frequency is related to the motor speed.

[0096] Step 5: When there is a need to stop the engine, use TarStopPos as the target stopping position for the engine, and CurPos as the actual engine position. Adjust the motor torque to stop the engine at TarStopPos.

[0097] Step 6: When there is a need to start the engine, the VCU controls the motor torque to drive the engine to start, and records the number of starts (StartTimes).

[0098] Step 7: Obtain the vehicle's x / y acceleration in real time from the ESP, where the x-direction is the vehicle's forward and backward direction, and the y-direction is the vehicle's up and down direction;

[0099] Calculate the x-axis acceleration: Ax = f(x); where: Ax is the x-axis filtered acceleration; f() is a filtering function such as, but not limited to, first-order and second-order; x is the original acceleration of the vehicle in the forward and backward directions obtained from ESP.

[0100] Calculate the y-axis acceleration: Ay = f(y); where: Ay is the y-axis filtered acceleration; f() is a filtering function such as, but not limited to, first-order, second-order, etc.; y is the original acceleration of the vehicle in the vertical direction obtained from ESP.

[0101] Step 8: Evaluate the vehicle's NVH performance during engine start-up. The method can be as follows:

[0102]

[0103] Wherein: NVHEm is the NVH assessment result at the time of this start-up, representing the accuracy of the target stop position used during the previous engine stop. A represents the preset weighting coefficient, which is related to the vehicle's engine mounting and whether it is longitudinally or transversely mounted, and its value ranges from 0 to 1, which can be determined through calibration; Ax0 is the average value of Ax within 50ms before engine start-up control; Ay0 is the average value of Ay within 50ms before engine start-up control.

[0104] When a vehicle is driving normally, the acceleration in the Ax and Ay directions tends to be stable with minimal fluctuations. If there is a significant engine start-up jerk, then Ax and Ay will fluctuate considerably. The greater the jerk and the greater the fluctuation, the worse the NVH performance. Therefore, in some embodiments of this application, the fluctuation of Ax and Ay can be used to evaluate NVH performance. The 'a' value is related to whether the acceleration (i.e., the jerk) is more pronounced in the x-direction or the y-direction when the jerk occurs. If the jerk has a greater impact on the acceleration in the x-direction, then the 'a' value will be larger.

[0105] Step 9: Evaluate the reasonableness of the previous target stop position based on NVHEm. If NVHEm is greater than NVHEmTh (a preset requirement; when the set indicator is an NVH indicator, the preset requirement can be a preset threshold determined based on NVH), and the number of starts (StartTimes) after the engine stops and restarts from the same target stop position without meeting the preset requirement (NVHEm greater than NVHEmTh) is greater than StartTimesTh, then control the target stop position to enter the correction phase, triggering the engine target stop position dynamic correction function, and jump to step 10. Otherwise, jump to step 4.

[0106] Where: NVHEmTh is the start-up assessment result corresponding to the acceptable NVH index level, which can be determined through calibration;

[0107] StartTimesTh is the number of times to prevent false triggering. That is, correction is only triggered when NVHEmTh is unacceptable multiple times in a row. This value is determined by calibration.

[0108] Step 10: Dynamically adjust the target stopping position. Update TarStopPos according to the following rules:

[0109] TarStopPos=StopPosEp+StepPos*N-OffsetPos

[0110] Where: StopPosEp represents the target stop position read from the EEROM;

[0111] StepPos represents the correction stop position used in each correction; N is the number of learning iterations, which increments by 1 with each learning iteration, also indicating the number of times the correction stop position is changed; OffsetPos is the preset offset, which can be 5° in this embodiment. For example, when the initial target stop position is 30°, the preset offset can be ±5°, and the correction range can be 25° to 35°. When the correction step value of the target stop position is 1°, the correction stop positions included in this correction range can include 11 correction stop positions: 25°, 26°, 27°, 28°, 29°, 30°, 31°, 32°, 33°, 34°, and 35°.

[0112] For example, N can be used to determine whether learning is complete. Learning is considered complete when N is greater than or equal to NTh. NTh represents the number of learning checks, and its value is twice OffsetPos plus 1. In this scheme, it is set to 11. This allows the optimal stopping position to be learned within a correction range of ±5 degrees above and below the initial target stopping position StopPosEp. During the correction process, the stopping position and its NVH evaluation results at startup need to be recorded each time. As follows:

[0113] StartPosGrp[N] = TarStopPos

[0114] NVHEmGrp[N] = NVHEm

[0115] Where NVHEmGrp[N] represents the evaluation result corresponding to the stop position of the Nth learning or Nth correction; after learning is completed, jump to step 11, otherwise jump to step 4.

[0116] Step 11: Find the minimum value NVHEmMin from NVHEmGrp[N]. The stop position corresponding to this value is TarStopPosMin. Take TarStopPosMin as the target stop position after the end of this correction phase.

[0117] Update the target stop location in the EEROM and write it to the EEROM:

[0118] StopPosEp = TarStopPosMin

[0119] Update the target shutdown position needed for the rest of this ignition cycle, i.e., the target shutdown position needed for each engine shutdown during the hold phase:

[0120] TarStopPos=TarStopPosMin

[0121] Set the StartTime count to 0 and skip to step 4.

[0122] Through the above steps, the embodiments of this application can determine whether the target stopping position is reasonable in practical applications, and automatically correct it to find the ideal target stopping position when it is unreasonable.

[0123] Figure 2 , Figure 3 and Figure 4 In this embodiment, the target engine stop position is obtained through calibration and dynamic correction. Dynamic correction is used after the engine and vehicle leave the factory. Each time the engine is started, the ESP (Electronic Stability Program) provides the VCU with the vehicle's x / y axis acceleration. The VCU evaluates the vehicle's NVH (Noise, Vibration, and Harshness) level during startup based on the acceleration, thereby determining whether the previous stop position meets the requirements. If the requirements are not met, the dynamic correction function for the engine target stop position is triggered. A better target stop position is found during the correction process.

[0124] In the various embodiments shown above, after obtaining the initial target stopping position of the engine, during the engine start-stop process, the target stopping position is evaluated based on the index parameters to obtain the evaluation result, and the target stopping position of the engine is corrected based on the evaluation result. Based on the initial target stopping position, the target stopping position is accurately maintained at the position of minimum starting resistance of the engine through dynamic correction, thereby improving the accuracy of the target stopping position.

[0125] In addition, this application embodiment also provides a control device for the engine stop position. The control device includes a storage medium and a processor. The storage medium stores a computer program that is run by the processor. When the computer program is run by the processor, it causes the processor to execute any of the above-mentioned methods for determining the road surface adhesion state.

[0126] Figure 5 A schematic block diagram of a control device 100 for the engine stop position according to an embodiment of this application is shown. Figure 5 As shown, the engine stop position control device 100 according to an embodiment of this application may include a storage medium 110 and a processor 120. The storage medium 110 stores a computer program executed by the processor 120. When the computer program is executed by the processor 120, the processor 120 performs the engine stop position control method described above according to an embodiment of this application. Those skilled in the art can understand the specific operation of the engine stop position control device 100 deployment device according to the embodiments of this application in conjunction with the foregoing content; for the sake of brevity, it will not be described in detail here.

[0127] The storage medium 110 may include, for example, a memory card of a smartphone, a storage component of a tablet computer, a hard disk of a personal computer, a read-only memory (ROM), an erasable programmable read-only memory (EPROM), a portable compact disc read-only memory (CD-ROM), a USB memory, or any combination of the above storage media. A computer-readable storage medium may be any combination of one or more computer-readable storage media.

[0128] In addition, this application also provides a vehicle, which includes an engine, a motor, and a control device for any of the aforementioned engine stop positions. The vehicle may be equipped with structures such as, but not limited to, a chassis, wheels, a cargo box, doors, and a transmission. The vehicle can be, but is not limited to, SUVs, sedans, and pickup trucks. This vehicle can be applicable to any type of hybrid electric vehicle, including but not limited to PHEVs, HEVs, and range-extended vehicles, as long as the vehicle's hybrid system has an engine and a motor for controlling the engine's start and stop, it can be used as the vehicle described in this application.

[0129] The present invention has been described through the above embodiments. However, it should be understood that the above embodiments are for illustrative purposes only and are not intended to limit the invention to the scope of the described embodiments. Furthermore, those skilled in the art will understand that the present invention is not limited to the above embodiments, and many more variations and modifications can be made based on the teachings of the present invention, all of which fall within the scope of protection claimed by the present invention. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for controlling the engine stop position, characterized in that, include: Obtain the initial target stopping position of the engine; During the engine start-stop process, the target shutdown position is evaluated based on index parameters to obtain an evaluation result; wherein, When the engine is started, the target stopping position used when the engine was last stopped is evaluated according to the index parameters to obtain the evaluation result of the target stopping position used when the engine was last stopped; the index parameters are acceleration in the NVH index, and the acceleration includes the vehicle's longitudinal acceleration and vertical acceleration; the evaluation result is determined based on the preset weighting coefficient, the vehicle's longitudinal acceleration and vertical acceleration; Based on the evaluation results, the target shutdown position of the engine is corrected.

2. The control method as described in claim 1, characterized in that, When starting the engine, the evaluation result of determining the target stopping position used when the engine was last stopped, based on preset weighting coefficients, the vehicle's longitudinal acceleration, and vertical acceleration, includes: When starting the engine, the evaluation result NVHEm of the target shutdown position used when the engine was last shut down is calculated using the following formula: Where 'a' represents the preset weight coefficient; Ax represents the acceleration of the vehicle in the forward and backward direction; Ay represents the acceleration of the vehicle in the vertical direction; Ax0 represents the average value of Ax within a preset time period before the engine starts; Ay0 represents the average value of Ay within a preset time period before the engine starts.

3. The control method as described in claim 2, characterized in that, The longitudinal acceleration Ax of the vehicle is: the acceleration after filtering the original longitudinal acceleration of the vehicle; wherein the original longitudinal acceleration of the vehicle is obtained from the vehicle's electronic stability system; and / or, The vertical acceleration Ay of the vehicle is: the acceleration after filtering the original vertical acceleration of the vehicle; wherein, the original vertical acceleration of the vehicle is obtained from the vehicle's electronic stability system.

4. The control method as described in claim 1, characterized in that, The specified parameter is the noise level in the NVH (Noise, Vibration, and Harshness) index.

5. The control method as described in claim 1, characterized in that, The specified parameter is the starting resistance of the engine during startup.

6. The control method according to any one of claims 1 to 5, characterized in that, The step of correcting the target stopping position of the engine based on the evaluation results includes: Based on the evaluation results, the target shutdown position of the engine is dynamically adjusted.

7. The control method as described in claim 6, characterized in that, The step of dynamically correcting the target shutdown position of the engine based on the evaluation results includes: If the evaluation result fails to meet the preset requirements at least once, the target shutdown position is controlled to enter the correction phase.

8. The control method as described in claim 7, characterized in that, The step of dynamically correcting the target shutdown position of the engine based on the evaluation results further includes: After controlling the target stopping position to enter the correction stage, each of the preset multiple correction stopping positions is sequentially used as the target stopping position of the correction stage, and the evaluation result of each correction stopping position in the correction stage is obtained. From all the correction stop positions evaluated during the correction phase, the optimal evaluation result is selected, and the correction stop position corresponding to the optimal evaluation result is taken as the target stop position after the correction phase ends.

9. The control method as described in claim 8, characterized in that, Multiple of the aforementioned correction stop positions are located within the correction range; The correction interval is defined as the interval determined by a preset offset based on the initial target stopping position.

10. The control method as described in claim 6, characterized in that, The step of dynamically correcting the target shutdown position of the engine based on the evaluation results includes: When the evaluation result meets the preset requirements, the target stopping position is controlled to enter the holding phase.

11. The control method as described in claim 1, characterized in that, The process of evaluating the target shutdown position based on index parameters during the engine start-stop process, and obtaining the evaluation result, further includes: The crankshaft position of the engine is determined at least based on the mechanical angle of the electric motor in the vehicle where the engine is located.

12. The control method as described in claim 11, characterized in that, Determining the crankshaft position of the engine, at least based on the mechanical angle of the electric motor in the vehicle where the engine is located, includes: The crankshaft position of the engine is determined based on the mechanical angle of the vehicle's motor, the phase difference between the motor and the engine, and the speed ratio.

13. The control method as described in claim 12, characterized in that, Determining the crankshaft position of the engine based on the mechanical angle of the vehicle's motor, the phase difference between the motor and the engine, and the speed ratio includes: The crankshaft position CurPos of the engine is determined using the following formula: CurPos=f((CurMotorPos-MotorPosZero) / R) Wherein, CurMotorPos represents the mechanical angle of the motor; MotorPosZero represents the phase difference between the electric motor and the engine; R represents the speed ratio between the electric motor and the engine; f() represents the filter function.

14. The control method according to any one of claims 11 to 13, characterized in that, The process of evaluating the target shutdown position based on index parameters during the engine start-stop process, and obtaining the evaluation result, further includes: Based on the crankshaft position of the engine, the engine is controlled to stop at the target stopping position.

15. A control device for the engine stop position, characterized in that, include: A storage medium and a processor, wherein the storage medium stores a computer program executed by the processor, the computer program, when executed by the processor, causes the processor to perform the control method for the engine stop position as described in any one of claims 1 to 14.

16. A vehicle, characterized in that, include: Engine and motor; And the engine stop position control device as described in claim 15.

Images