System and method for monitoring torque in hybrid vehicle

Abstract

The present disclosure provides a system and method for monitoring torque in a hybrid vehicle capable of preventing misdiagnosis when determining whether an abnormality exists when a torque command is generated. Therefore, torque monitoring can be accurately performed. The method includes comparing a command torque limit value determined by adding a compensation value to a request torque to be monitored with a sum of command torques of respective ones of the power sources in the hybrid vehicle to determine whether there is an abnormality in generating a torque command for the power sources in the hybrid vehicle. The method also includes limiting a compensation value added to the requested torque to be monitored to a drive system limit value at a vehicle level to calculate a commanded torque limit value.

Description

Technical Field

[0001] The present disclosure relates to systems and methods for monitoring torque in a hybrid vehicle. Background Art

[0002] A hybrid vehicle is a vehicle that travels using an engine (internal combustion engine) and an electric motor as power sources. A hybrid vehicle generally includes a powertrain. For example, a hybrid vehicle may include a transmission-mounted electric drive (TMED) type hybrid system.

[0003] In a TMED type hybrid system, an engine clutch is provided between the engine and the electric motor, and the engine and the electric motor are drive devices for driving the vehicle. In addition, a transmission is connected to the output side of the electric motor. Further, an inverter for driving and controlling the electric motor is mounted in the vehicle. The electric motor is connected to a high-voltage main battery in the vehicle in a rechargeable and dischargeable manner via the inverter.

[0004] During electric motor drive, the inverter converts direct current (DC) supplied from the battery into alternating current (AC) and applies it to the electric motor via a power cable. During electric motor regeneration, the inverter converts the AC generated in the electric motor into DC and supplies it to the battery.

[0005] In addition, the vehicle is equipped with an electric motor, that is, a hybrid starter generator (HSG), that is, a starter generator connected to the engine to achieve constant power transmission, in order to start the engine or generate electricity using the rotational power transmitted from the engine. Similar to the electric motor for driving the vehicle, the HSG can operate as both an electric motor and a generator, and is connected to the battery in a rechargeable and dischargeable manner via the inverter.

[0006] In a hybrid vehicle, a regeneration mode is executed, in which during coasting, due to inertia or braking, the kinetic energy of the vehicle is recovered as electric energy by the power generation of the electric motor to charge the battery. In a hybrid vehicle, the function of the regeneration mode is essential for improving vehicle efficiency and fuel efficiency.

[0007] In addition, in a hybrid vehicle, power needs to be appropriately distributed to the engine and the electric motor to minimize fuel consumption and improve vehicle fuel efficiency. The process of determining a target operating point and generating an engine torque command and an electric motor torque command in a TMED type hybrid vehicle is as follows.

[0008] Figure 1 is a block diagram showing the structure of a control system configured to perform power control and shift control in a hybrid vehicle. As Figure 1 shown, in a hybrid vehicle, a plurality of controllers 10 to 40 perform cooperative control of power control and shift control in the vehicle.

[0009] First, the hybrid control unit (HCU) 10 can be regarded as a high-level controller that determines the driver-requested torque according to the driver's driving intention based on vehicle operation information such as the driver's accelerator pedal input value (APS value) and brake pedal input value (BPS value).

[0010] Here, among the driver's operation input values, the accelerator pedal input value can be detected by the accelerator pedal position sensor (APS), and the brake pedal input value can be detected by the brake pedal position sensor (BPS).

[0011] In addition, the HCU 10 determines the engine on / off mode (i.e., driving mode) that satisfies the driver-requested torque, and distributes the torque to the drive device based on the determined driver-requested torque and engine on / off mode information.

[0012] The HCU 10 determines the engine torque and motor torque that satisfy the driver-requested torque according to the distribution ratio and distributed torque distribution for power distribution, and then generates and outputs torque commands for each power source.

[0013] Thereafter, the engine control unit (ECU) 20 and the motor control unit (MCU) 30 respectively receive the engine torque command and the motor torque command from the HCU 10, and control the torque of the engine and the torque of the motor according to the respective received torque commands.

[0014] Together with the power control of the vehicle described above, shift control is performed. Here, the transmission control unit (TCU) 40 determines the target shift stage based on the information collected in the vehicle and controls the operation of the transmission so that the shift to the target shift stage is performed.

[0015] In addition, the TCU 40 provides the HCU 10 with current shift state information such as the target shift point, shift class, and shift phase. The HCU 10 performs torque intervention control and the like with reference to the shift state information.

[0016] In a conventional system, the HCU (which is a high-level controller) or the vehicle domain control unit (VDCU) in a conventional TMED vehicle cannot detect excessive torque relative to the driver's demand, which may occur due to software or hardware errors in the basic control logic for torque determination and command generation for each power source (engine, motor, and HSG).

[0017] For this reason, in order to ensure safety during acceleration and deceleration at the vehicle level, a torque monitoring logic that can monitor torque determination and command generation in the basic control logic is being developed and applied to the vehicle.

[0018] When applying the torque monitoring logic as described above, conventionally, due to the limitations of the microcomputer, the basic control logic is simplified, and torque determination and command generation are monitored in the simplified basic control logic.

[0019] However, according to the conventional torque monitoring logic, during the process of receiving the torque command value calculated in the basic control logic and diagnosing abnormalities such as errors in torque determination, command generation, and hardware failures in the basic control logic, errors may occur, resulting in misdiagnosis of abnormalities.

[0020] For example, external intervention torques such as shift, active shift control (ASC), and traction control system (TCS) received from other controllers must be reflected in the torque distribution logic for determining the final torque command value of each power source (engine, motor, and HSG). However, when an error occurs during the process of reflecting the external intervention torque, even if there is an error in the basic control logic, it may be misdiagnosed as normal.

[0021] The above information disclosed in this background section is only for enhancing the understanding of the background of the present disclosure. Therefore, the background section may contain information that does not constitute related art known to those of ordinary skill in the art. SUMMARY OF THE INVENTION

[0022] The present disclosure is directed to solving the above problems related to the related art. An object of the present disclosure is to provide a system and method for monitoring torque in a hybrid vehicle, which can prevent misdiagnosis when determining whether there are abnormalities in torque determination and instruction generation in the basic control logic, thereby accurately performing torque monitoring.

[0023] The object of the present disclosure is not limited to the foregoing. Other objects not mentioned herein will be more clearly understood by those of ordinary skill in the art to which the present disclosure pertains based on the following description.

[0024] On the one hand, a method for monitoring torque in a hybrid vehicle is provided. The method includes: determining, by a controller, a driver-requested torque and a driving mode of the hybrid vehicle. The method further includes allocating, by the controller, the driver-requested torque to each of the power sources in the hybrid vehicle based on the driving mode. The method additionally includes adding, by the controller, an intervention torque to the allocated torque of each power source. The method also includes determining, by the controller, a commanded torque of each power source after reflecting the intervention torque. The method further includes determining, by the controller, a requested torque to be monitored based on vehicle operation information. The method also includes determining, by the controller, a compensation value for each power source considering the intervention torque based on the determined commanded torque of each power source after reflecting the intervention torque and the allocated commanded torque of each power source before reflecting the intervention torque. The method further includes limiting, by the controller, the compensation value of each power source to a corresponding drive system limit value in the respective drive systems of the power sources in the hybrid vehicle. The method also further includes determining, by the controller, a commanded torque limit value using the corresponding limited compensation value and the determined requested torque to be monitored. The method also includes determining, by the controller, whether there is an abnormality in determining the commanded torque of each power source based on a comparison of the determined commanded torque limit value with the sum of the commanded torques of the power sources.

[0025] In an embodiment, limiting the determined compensation value to the corresponding drive system limit value may include subtracting the commanded torque of the power source before reflecting the intervention torque from the commanded torque of the power source after reflecting the intervention torque to determine the compensation value of the power source, and limiting the determined compensation value of the power source using the corresponding drive system limit value.

[0026] In an embodiment, determining the commanded torque limit value may include determining a total compensation value by summing the limited compensation values of each power source. Determining the commanded torque limit value may further include determining the commanded torque limit value using the determined total compensation value and the requested torque to be monitored.

[0027] In an embodiment, determining the commanded torque limit value may include determining the commanded torque limit value by adding the total compensation value and the requested torque to be monitored.

[0028] In an embodiment, the power source may include an engine and an electric motor configured to drive the vehicle, and a hybrid starter generator (HSG) connected to the engine to transmit power to start the engine or generate electricity using engine power.

[0029] In an embodiment, the drive system limit values may include an engine system limit value, a motor system limit value, and an HSG system limit value. The engine system limit value may be determined based on the engine speed and the driving mode. The motor system limit value and the HSG system limit value may be determined based on the state of charge (SOC) of the main battery.

[0030] In an embodiment, the power source may include an engine and a motor configured to drive the vehicle, and a hybrid starter generator (HSG) connected to the engine to transmit power to start the engine or generate electricity using the engine power.

[0031] In an embodiment, determining the commanded torque limit value may include using a value obtained by adding a limited compensation value to the requested torque to be monitored to determine the commanded torque limit value.

[0032] In an embodiment, determining whether there is an abnormality in determining the commanded torque of each power source may include: when the commanded torque limit value is equal to or less than the sum of the commanded torques of the respective power sources, determining that there is an abnormality in determining the commanded torque of each power source; and when the commanded torque limit value is greater than the sum of the commanded torques of the respective power sources, determining that the determination of the commanded torque of each power source is normal.

[0033] In another aspect, a system for monitoring torque in a hybrid vehicle is provided. The system includes a controller configured to determine a driver requested torque and a driving mode of the hybrid vehicle. The controller is further configured to distribute the driver requested torque to each of the power sources in the vehicle based on the determined driving mode. The controller is also configured to add an intervention torque to the distributed torque of each power source to determine the commanded torque of each power source after reflecting the intervention torque. The controller is also configured to determine the requested torque to be monitored based on vehicle operation information. The controller is also configured to determine a compensation value for each power source considering the intervention torque based on the determined commanded torque of each power source after reflecting the intervention torque and the distributed commanded torque of each power source before reflecting the intervention torque. The controller is further configured to limit the determined compensation value to the drive system limit values. The controller is also configured to use the limited compensation value and the determined requested torque to be monitored to determine the commanded torque limit value. The controller is also configured to determine whether there is an abnormality in determining the commanded torque of each power source based on a comparison of the determined commanded torque limit value with the sum of the commanded torques of the respective power sources.

[0034] In an embodiment, the controller may be configured to subtract the command torque of each power source after the intervention torque is reflected from the command torque of each power source before the intervention torque is reflected to determine a compensation value for each power source. The controller may also be configured to limit the compensation value determined for each power source using a corresponding drive system limit value among the drive system values of the power source.

[0035] In an embodiment, the controller may be configured to determine a total compensation value by summing the limited compensation values of each power source. The controller may also be configured to determine a command torque limit value using the determined total compensation value and a requested torque to be monitored.

[0036] In an embodiment, the controller may be configured to determine a command torque limit value by adding the total compensation value to the requested torque to be monitored.

[0037] In an embodiment, the power source may include an engine and an electric motor configured to drive a vehicle, and a hybrid starter generator (HSG) connected to the engine to transmit power to start the engine or generate electricity using engine power.

[0038] In an embodiment, the drive system limit values may include an engine system limit value, an electric motor system limit value, and an HSG system limit value. The engine system limit value may be determined based on the engine speed and the driving mode, and the electric motor system limit value and the HSG system limit value may be charge and discharge limit values determined based on the state of charge (SOC) of the main battery.

[0039] In an embodiment, the controller may be configured to determine a command torque limit value using a value obtained by adding the limited compensation value to the requested torque to be monitored.

[0040] In an embodiment, the controller may be configured to: when the command torque limit value is equal to or less than the sum of the command torques of each power source, determine that there is an abnormality in the process of determining the command torque of each power source. The controller may also be configured to, when the command torque limit value is greater than the sum of the command torques of each power source, determine that the process of determining the command torque of each power source is normal.

[0041] Other aspects and embodiments of the present disclosure are described below.

[0042] It should be understood that the term "vehicle" or "vehicular" or other similar terms as used herein generally includes motor vehicles. Such motor vehicles can include passenger cars, including sport utility vehicles (SUVs), buses, trucks, various commercial vehicles, boats including various vessels and ships, airplanes, etc. Such motor vehicles can also include hybrid vehicles, electric vehicles, plug-in hybrid vehicles, hydrogen-powered vehicles, and other alternative fuel vehicles (e.g., fuels derived from resources other than petroleum). As mentioned herein, a hybrid vehicle is a vehicle that has two or more power sources, e.g., a vehicle powered by both gasoline and electricity.

[0043] The above and other features of the present disclosure are described below. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The above and other features of the present disclosure will be described in detail below with reference to certain embodiments of the present disclosure shown in the accompanying drawings. In the following, the drawings are given by way of illustration only and thus do not limit the present disclosure, and wherein:

[0045] Figure 1 is a block diagram showing the structure of a control system configured to perform power control and shift control in a hybrid vehicle;

[0046] Figure 2 is a flowchart showing a method for monitoring torque according to the related art;

[0047] Figure 3 shows a graph that respectively shows the commanded torque limit value and the sum of the commanded torques for each power source in a method for monitoring torque according to the related art and according to an embodiment of the present disclosure;

[0048] Figure 4 is a block diagram showing the structure of a controller configured to perform a process of diagnostic torque monitoring according to an embodiment of the present disclosure; and

[0049] Figure 5 is a flowchart showing the process of diagnostic torque monitoring according to an embodiment of the present disclosure.

[0050] It should be understood that the drawings are not necessarily drawn to scale, presenting a somewhat simplified representation of various features showing the basic principles of the present disclosure. The specific design features of the present disclosure (including, for example, specific dimensions, orientations, positions, and shapes) will be determined in part by the particular intended application and use environment.

[0051] In the drawings, throughout several views of the drawings, the same reference numerals refer to the same or equivalent components of the present disclosure. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0052] In the following, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The description of the specific structures or functions presented in the embodiments of the present disclosure is merely illustrative for the purpose of explaining the embodiments according to the concept of the present disclosure. Embodiments according to the concept of the present disclosure can be implemented in various forms. In addition, these descriptions should not be construed as being limited to the embodiments described herein, and should be understood to include all modifications, equivalents, and alternatives falling within the concept and scope of the present disclosure.

[0053] In the present disclosure, terms such as "first" and / or "second" may be used to describe various components, but these components are not limited by the terms. These terms are only used to distinguish one component from another. For example, without departing from the scope of the embodiments of the present disclosure, the first component may be referred to as the second component, and similarly, the second component may be referred to as the first component.

[0054] It should be understood that when a component is referred to as being "connected to" or "in contact with" another component, the component may be directly connected to or in contact with the other component, or there may also be one or more intermediate components. In contrast, when a component is referred to as being "directly connected to" or "directly in contact with" another component, there are no intermediate components. Other terms used to describe the relationship between components should be interpreted in a similar manner (e.g., "between" and "directly between", "adjacent" and "directly adjacent", etc.).

[0055] Throughout the specification, the same reference numerals denote the same components. The terms used herein are for the purpose of illustrating the embodiments and are not intended to limit the present disclosure. In this specification, the singular form includes the plural meaning unless otherwise specified. The terms "comprises" and / or "comprising" used in this specification mean that the recited components, steps, operations, and / or elements do not exclude the presence or addition of one or more other components, steps, operations, and / or elements. This also applies to words such as "has" and "includes" and their variants.

[0056] When a component, device, element, etc. of the present disclosure is described as having a purpose or performing an operation, function, etc., the component, device, or element should be considered herein as being "configured to" meet the purpose or perform the operation or function.

[0057] The terms "unit", "module", "controller", etc. used in the present disclosure represent a unit that processes at least one function or operation, and can be implemented by hardware, software, or a combination thereof. The operations or functions of the methods described in connection with the forms disclosed herein can be directly embodied in a hardware or software module executed by a processor, or in a combination thereof.

[0058] According to an embodiment of the present disclosure, a system and method for monitoring torque in a hybrid vehicle are provided, and the system and method can prevent misdiagnosis when determining whether there is an abnormality in torque determination and command generation. More specifically, according to an embodiment of the present disclosure, a system and method capable of preventing misdiagnosis due to an error in the process of reflecting external intervention torque are provided. Therefore, torque monitoring can be accurately performed.

[0059] Hereinafter, before describing an embodiment of the present disclosure, problems in the related art will be described in more detail to help understand the present disclosure.

[0060] Figure 2 It is a flowchart showing a method for monitoring torque according to the related art. Figure 2 It shows the basic control logic for determining torque and generating commands for each power source in a hybrid vehicle and the torque monitoring logic of the related art. In the following description, the power sources include an engine and an electric motor configured to drive the vehicle. The power sources also include a hybrid starter generator (HSG), which is an electric motor configured to start the engine and generate electricity using engine power.

[0061] First, in step or operation S1, the controller receives an operation input value of the driver, for example, the driver's pedal input values (e.g., APS value and BPS value). In step or operation S2, the controller determines the driver-requested torque in the basic control logic of the controller based on vehicle operation information such as the driver's operation input value to generate a torque command for each power source.

[0062] For example, in the basic control logic of the controller, an acceleration pedal input value (APS value) detected by an acceleration pedal position sensor or a brake pedal input value (BPS value) detected by a brake pedal position sensor can be received to determine the driver-requested torque corresponding to the acceleration pedal input value or the brake pedal input value.

[0063] In step or operation S3, the basic control logic determines the driving mode (power train (PT) mode) of the vehicle based on charge and discharge information, such as a charge and discharge strategy depending on the determined driver-requested torque and battery state. In step or operation S4, the controller distributes the driver-requested torque to each power source according to the determined driving mode to determine the torque of each power source (i.e., engine torque, motor torque, and HSG torque). The engine torque, motor torque, and HSG torque are the torques before reflecting the intervention torque, that is, the command torques of each power source before reflecting the intervention torque allocated from the driver-requested torque.

[0064] In step or operation S5, the controller selectively reflects the intervention torque, such as shift, ASC, and TCS received from other controllers, in the torque of each determined power source according to the torque distribution logic in the basic control logic to determine the final torque (command value) of each power source. The controller thus generates and outputs the final torque command for each power source.

[0065] When reflecting the intervention torque in the torque distribution logic, the intervention torque can be added to the torque of each power source from which the requested torque is distributed, that is, the engine torque, the motor torque, and the HSG torque, to determine the final torque of each power source. Then, using the determined final torque as the command value, the final torque command for each power source is generated and then output.

[0066] Here, the torque commands for each power source (i.e., the engine torque command, the motor torque command, and the HSG torque command) are commands for controlling the operation of each corresponding power source. Cooperative control is performed according to each of the corresponding torque commands to control the operations of the engine, the motor, and the HSG.

[0067] The torque distribution logic is as follows: Before generating the torque commands for each power source, intervention torques such as shift, ASC, and TCS are added to the torque of each power source to calculate the commanded torque (the final torque command value). The commanded torque of each power source to which the intervention torque is added is herein referred to as "the commanded torque of each power source after reflecting the intervention torque". The commanded torque of each power source after reflecting the intervention torque is the final command value obtained after executing the final torque calculation logic.

[0068] In addition to the torque determination and command generation performed in the basic control logic, in step or operation S11, the torque monitoring logic in the controller configured to monitor the torque determines the requested torque to be monitored based on vehicle operation information such as the driver's operation input value.

[0069] For example, based on the accelerator pedal input value (APS value) or the brake pedal input value (BPS value) used to determine the driver's requested torque in the basic control logic, the requested torque to be monitored can be separately determined in the torque monitoring logic of the controller.

[0070] The process of determining the requested torque to be monitored in the torque monitoring logic can be constructed by shortening the process of determining the driver's requested torque in the basic control logic.

[0071] In addition, the torque monitoring logic receives, from the basic control logic, the commanded torque of each power source after the intervention torque (torque command value) is reflected by the torque distribution logic. The torque monitoring logic also receives, from the driver-requested torque, the determined commanded torque for each power source before the intervention torque (the torque before the final torque calculation logic).

[0072] Thereafter, based on the received commanded torque (torque command value) of each power source after the intervention torque is reflected and the commanded torque of each power source before the intervention torque ( Figure 2 "the torque of each power source before the final torque calculation logic" in ), at step or operation S12, the torque monitoring logic determines a separate compensation value for each power source in which torque intervention is considered. At step or operation S13, the controller adds the determined compensation value of each power source to the separate compensation value of each power source in which torque intervention is considered to determine the total compensation value (i.e., the sum of the compensation values of each power source), and adds the determined total compensation value to the requested torque to be monitored to determine the commanded torque limit value.

[0073] During the process of determining the compensation value, the controller subtracts the commanded torque of each power source before the intervention torque from the commanded torque of each power source after the intervention torque is reflected to determine the compensation value of each power source. The controller then adds the determined compensation values of each power source to determine the total compensation value.

[0074] In other words, the controller determines the total compensation value by adding the following values: i) the engine torque compensation value obtained by subtracting the engine torque allocated before the intervention torque from the engine commanded torque (engine torque command value) after the intervention torque is reflected; ii) the motor torque compensation value obtained by subtracting the motor torque allocated before the intervention torque from the motor commanded torque (motor torque command value) after the intervention torque is reflected; and iii) the HSG torque compensation value obtained by subtracting the HSG torque before the intervention torque from the HSG commanded torque (HSG torque command value) after the intervention torque is reflected.

[0075] Here, depending on the driving mode (PT mode), some of the engine torque, motor torque, and HSG torque before and after the intervention torque is reflected may be 0. In this way, the determined total compensation value is added to the requested torque to be monitored to determine the commanded torque limit value.

[0076] The commanded torque received from the basic control logic at step or operation S12 to determine the compensation value of each power source is the commanded torque of each power source after the intervention torque (torque command value) is reflected, which is the commanded torque of each power source after the final torque calculation logic.

[0077] In addition, the command torque of each power source before subtracting the intervention torque reflected to determine the compensation value of each power source in step or operation S12 may be the torque of each power source before the final torque calculation logic. Therefore, the compensation value for each power source may be a value obtained by subtracting the torque of each power source before the final torque calculation logic from the command torque of each power source after the final torque calculation logic.

[0078] In step or operation S14, the torque monitoring logic compares the determined command torque limit value with the sum of the command torques of each power source (the torque command value of each power source) after reflecting the intervention torque received from the basic control logic (i.e., the final torque command value of each power source) to diagnose whether there is an abnormality in the basic control logic, where the final torque command value of each power source is the sum of the engine command torque, the motor command torque, and the HSG command torque.

[0079] When the command torque limit value is equal to or less than the sum of the command torques of each power source, it is determined in step or operation S15 that there is an abnormality in the basic control logic. Otherwise, the basic control logic is judged to be normal in step or operation S16.

[0080] In this way, the torque monitoring logic uses the command torque of each power source after reflecting the intervention torque and the torque of each power source received from the basic control logic before reflecting the intervention torque to determine the compensation value considering the intervention torque.

[0081] The compensation value (total compensation value) to be added to the requested torque to be monitored is determined by adding the values obtained by subtracting the engine torque, motor torque, and HSG torque values allocated before reflecting the intervention torque from the engine command torque, motor command torque, and HSG command torque values after reflecting the intervention torque in ii). However, regarding the compensation value in the related art, the output limit of the system is not considered. In other words, the compensation value has no limit.

[0082] For this reason, during the process of adding the intervention torque to the torque of each power source allocated in the torque distribution logic of the basic control logic, an error may occur, thereby excessively increasing the command torque of each power source used to calculate the compensation value in the torque monitoring logic.

[0083] When the excessively increased command torque of each power source after reflecting the intervention torque in the basic control logic is transmitted to the torque monitoring logic, the torque monitoring logic subtracts the command torque of each power source before reflecting the intervention torque from the excessively increased command torque of each power source after reflecting the intervention torque. As a result, the compensation value considering the torque intervention also increases, and therefore, the command torque limit value reflecting this compensation value also increases, ultimately possibly leading to misdiagnosis.

[0084] Reference Figure 2 to the flowchart in Figure 2 , by comparing the sum of the commanded torque limit value and the commanded torque for the power source at step or operation S14, it is determined whether there is an abnormality. In the case where the commanded torque limit value increases abnormally, although there are abnormalities in torque determination and command generation in the basic control logic, the process may be misdiagnosed as normal in operation or step S16.

[0085] According to an embodiment of the present invention, the sum of the commanded torque limit value obtained by adding a compensation value to the requested torque to be monitored and the commanded torque for the power source is compared, and the compensation value for each power source is limited to the drive system limit value, so as to prevent the commanded torque limit value compared with the sum of the commanded torques for the power sources from increasing excessively due to an error in the basic control logic.

[0086] As described above, when the compensation value for each power source is limited to the drive system limit value, abnormal increase of the commanded torque limit value can be prevented, and errors in the torque distribution logic etc. in the basic control logic can be accurately diagnosed, thereby strengthening the torque monitoring logic to ensure stability.

[0087] At Figure 2 step or operation S13 in Figure 2 , the compensation value added to the requested torque to be monitored is the total compensation value obtained by adding up all the compensation values of the power sources limited to the corresponding system limit values of the power sources. In addition, the sum of the commanded torques of the power sources is the value obtained by summing up the commanded torques of the power sources input to the torque monitoring logic after being determined in the basic control logic, that is, the sum of the engine torque, the motor torque, and the HSG torque after the intervention torque is reflected by the torque distribution logic. In other words, the sum of the commanded torques of the power sources is the torque obtained by adding up all the torque command values of the power sources generated at step or operation S5 in Figure 2 . Figure 2

[0088] In addition, the drive system limit value may include an engine system limit value, a motor system limit value, and an HSG system limit value. In other words, the compensation value (torque command value) of each power source obtained by subtracting the commanded torque of each power source before the intervention torque is reflected from the commanded torque of each power source after the intervention torque is reflected is respectively limited to the engine system limit value, the motor system limit value, and the HSG system limit value.

[0089] In addition, the compensation values of each power source limited by the corresponding system limit values are added up to determine the total compensation value (the sum of the compensation values of each power source). Then the determined total compensation value is added to the requested torque to be monitored to determine the commanded torque limit value.

[0090] According to an embodiment of the present disclosure, the system limit value is the torque value that the engine and the electric motor (drive motor, HSG) can generate through the system. According to an embodiment of the present disclosure, the engine system limit value can be determined by the controller based on the engine speed (rpm), driving mode (PT mode), etc. In addition, according to an embodiment of the present disclosure, the electric motor system limit value and the HSG system limit value can be the charge and discharge limit values determined based on the state of charge (SOC) of the main battery.

[0091] Figure 3 The graph shows the sum of the commanded torque limit values and the commanded torques for each power source in the methods for monitoring torque according to the related art and according to an embodiment of the present disclosure, respectively. Figure 3 The graph shows a comparison between the related art where no limit is applied and the embodiment of the present disclosure where the limit is applied.

[0092] Figure 3 The commanded torque limit value in is obtained by adding a compensation value to the requested torque to be monitored. In addition, the sum of the engine torque, the electric motor torque, and the HSG torque is a value obtained by adding all the commanded torques of the power sources after reflecting the intervention torque distributed by the torque distribution logic, that is, the sum of the torque command values of the engine, the electric motor, and the HSG.

[0093] As Figure 3 shown, according to the related art, the compensation value is not limited to the system limit value. Therefore, when the commanded torque of each power source after reflecting the intervention torque increases excessively due to an error in the basic control logic, the compensation value increases excessively and the commanded torque limit value increases excessively.

[0094] As a result, since the commanded torque limit value rises abnormally, the commanded torque limit value is always larger than the sum of the commanded torques of the power sources. Therefore, although there is an error in the basic control logic, it may be misdiagnosed as normal and accurate diagnosis cannot be performed.

[0095] However, according to an embodiment of the present disclosure, the compensation value is limited to the sum of the engine and electric motor (drive motor, HSG) system limit values, preventing the commanded torque limit value from increasing abnormally, and thus it can be accurately diagnosed when there is an error in the torque distribution logic, etc.

[0096] In other words, in the related art, since a compensation value greater than the torque that the engine and the electric motor can systemically generate can be added to the requested torque to be monitored, when an error occurs in the torque distribution logic, the commanded torque limit value also increases, making diagnosis impossible.

[0097] In contrast, according to an embodiment of the present disclosure, when an error occurs in the torque distribution logic, the commanded torque limit value is increased, but an abnormal increase is prevented. Therefore, when an error occurs in the torque distribution logic, the commanded torque limit value can be accurately diagnosed.

[0098] Figure 4 is a block diagram showing the structure of a controller configured to execute a process of diagnosing torque monitoring according to an embodiment of the present disclosure. Figure 4 The block diagram also shows components configured to execute basic control logic according to an embodiment.

[0099] Figure 5 is a flowchart showing a process of diagnosing torque monitoring according to an embodiment of the present disclosure. Figure 5 The flowchart also shows a process of generating a torque command for each power source in the basic control logic.

[0100] For Figure 4 the components in, when an error occurs in the torque distribution logic of the basic control logic, the error can be diagnosed. Among the errors occurring in the torque distribution logic of the basic control logic, an intervention torque is added to the torque of each power source that requests torque distribution from the driver to determine the torque of each power source (commanded torque, that is, the torque command value of each power source) after reflecting the intervention torque, and the commanded torque is excessively increased.

[0101] In an embodiment of the present disclosure, the controller 100 is configured to execute a process of diagnosing and monitoring torque. The controller 100 may be an HCU serving as a high-level controller or a vehicle domain control unit (VDCU) integrating multiple controllers including the HCU.

[0102] The controller 100 can be installed in a vehicle and can be used to control the torque of the vehicle drive system according to a driver's request. The controller 100 can also monitor whether the commanded torque values output to each power source are reliable.

[0103] In Figure 4 the example of, the controller 100 includes components configured to execute basic control logic, that is, the basic control logic unit 110. The basic control logic unit 110 includes an operation information receiver 111, a requested torque determiner 112, a driving mode determiner 113, and a torque distributor 114.

[0104] Refer to Figure 4 and Figure 5, in step or operation S1, the operation information receiver 111 receives signals (e.g., APS signal and BPS signal) from operation information detectors such as an accelerator pedal position sensor (APS) and a brake pedal position sensor (BPS). In step or operation S2, the requested torque determiner 112 determines the driver-requested torque based on vehicle operation information (i.e., vehicle operation information including the driver's operation input values (such as accelerator pedal input values) obtained from the signals received from the operation information detectors).

[0105] In step or operation S3, the driving mode determiner 113 determines the driving mode of the vehicle (e.g., power train (PT) mode) based on charge and discharge information, such as a discharge strategy depending on the determined driver-requested torque and battery state. In step or operation S4, the torque distributor 114 distributes the driver-requested torque to each power source according to the determined driving mode to determine the command torque of each power source that finally reflects the intervention torque.

[0106] The torque distributor 114 executes torque distribution logic. In the torque distribution logic, the intervention torque is added to the torque of each power source distributed from the driver-requested torque to determine the final command torque of each power source, in which the intervention torque is reflected at step or operation S4. When determining the command torque for each power source, torque commands for each power source are generated and output at step or operation S5.

[0107] Therefore, during the execution of the basic control logic, the command torque of each power source before reflecting the intervention torque (torque before the final torque calculation logic) and the command torque of each power source after reflecting the intervention torque (torque after the final torque calculation logic) are transmitted to the torque monitoring logic.

[0108] When the basic control logic is executed, the torque monitoring logic can be executed in the controller 100 simultaneously. The controller 100 also includes components configured to execute the torque monitoring logic, i.e., the torque monitoring logic unit 120.

[0109] The torque monitoring logic unit 120 may include a determiner 121 for the requested torque to be monitored, a command torque limit value determiner 122, a command torque summing unit 123, a command torque consistency determiner 124, a fault diagnoser 125, and a fail-safe controller 126.

[0110] Similar to the requested torque determiner 112 in the basic control logic, the determiner 121 of the requested torque to be monitored in the torque monitoring logic determines the driver-requested torque based on vehicle operation information including the driver's operation input values (such as the accelerator pedal input value). However, the determiner 121 of the requested torque to be monitored uses a process of determining the requested torque (wherein the process of determining the driver-requested torque in the basic control logic is shortened) to determine the requested torque to be monitored.

[0111] Thus, when the requested torque to be monitored is determined by a process in which the process of determining the driver-requested torque in the basic control logic is shortened, at step or operation S11, the commanded torque limit value determiner 122 adds the total compensation value (the sum of the compensation values of each power source) to the determined requested torque to be monitored to determine the commanded torque limit value.

[0112] In an embodiment, the compensation value is a value in which torque intervention performed through cooperative control with other controllers is considered. For example, the commanded torque limit value determiner 122 receives the torque of each power source before reflecting the torque intervention ( Figure 5 "the torque of each power source before the final torque calculation logic") and the torque of each power source after reflecting the torque intervention (the torque command value of each power source as the final commanded torque of each power source) from the basic control logic unit 110. At step or operation S12, the commanded torque limit value determiner 122 subtracts the torque of each power source before reflecting the torque intervention (the torque before the final torque calculation logic) from the commanded torque of each power source after reflecting the torque intervention to determine the compensation value of each power source.

[0113] In an embodiment, the commanded torque limit value determiner 122 determines the compensation value of each power source as described above, and then at step or operation S12-1, limits the compensation value of each power source to the respective system limit values at the vehicle level. In an embodiment, the commanded torque limit value determiner 122 compares the compensation value of each power source with the limit value of the power source (for example, the engine system limit value, the motor system limit value, and the HSG system limit value) to limit each compensation value of each power source not to exceed the system limit value of the corresponding power source.

[0114] At step or operation S13, the compensation values of the power sources limited by using the respective system limit values are added to determine the total compensation value (the sum of the compensation values of each power source), and the determined total compensation value is added to the requested torque to be monitored to calculate the commanded torque limit value.

[0115] As in the Figure 2 related art described, in Figure 5The command torque received from the basic control logic at step or operation S12 in [[]] to determine the compensation value for each power source is the command torque for each power source after reflecting the intervention torque (torque command value), which is the command torque for each power source after the final torque calculation logic.

[0116] In addition, at Figure 5 The command torque for each power source before reflecting the intervention torque, which is subtracted from the command torque for each power source at step or operation S12 in [[]] to determine the compensation value for each power source, can be the torque for each power source before the final torque calculation logic. Therefore, the compensation value for each power source can be a value obtained by subtracting the torque for each power source before the final torque calculation logic from the command torque for each power source after the final torque calculation logic.

[0117] The command torque summing unit 123 sums the command torque for each power source (value reflecting the intervention torque) received from the basic control logic unit 110. At step or operation S14, the command torque consistency determiner 124 then compares the command torque limit value determined by the command torque limit value determiner 122 with the command torque for each power source determined by the command torque summing unit 123 to determine whether the command torque is consistent.

[0118] When the command torque limit value is equal to or less than the sum of the command torques for each power source, at step or operation S15, the fault diagnostician 125 determines that there is an abnormality in the command torque and diagnoses a fault (such as an error in the torque distribution logic), and allows the fail-safe controller 126 to perform fail-safe control. When the command torque limit value is greater than the sum of the command torques for each power source, at step or operation S16, the fault diagnostician 125 diagnoses the process as normal.

[0119] As described above, the system and method for monitoring torque can prevent misdiagnosis of abnormalities in determining torque and generating commands in the basic control logic. Therefore, torque monitoring can be accurately performed.

[0120] As is apparent from the above description, the present disclosure provides the following effects.

[0121] In the system and method for monitoring torque in a hybrid vehicle according to an embodiment of the present disclosure, misdiagnosis in determining whether there is an abnormality in the basic control logic can be prevented, and the process of determining torque and generating commands can be accurately monitored.

[0122] According to an embodiment of the present disclosure, errors in the process of reflecting external intervention torque and determining the compensation value and misdiagnosis caused by the errors can be prevented.

[0123] Although the present disclosure has been described in detail with reference to exemplary embodiments, the scope of the present disclosure is not limited to the above embodiments. Various modifications and improvements made by those of ordinary skill in the art using the basic concepts of the present disclosure as defined in the following claims are also included within the scope of the present disclosure.

Claims

1. A method for monitoring torque in a hybrid vehicle, the method comprising: determining, by a controller, a driver requested torque and a driving mode of the hybrid vehicle; allocating, by the controller, the driver requested torque to each of power sources in the hybrid vehicle based on the driving mode; adding, by the controller, an intervention torque to the allocated driver requested torque of each power source; determining, by the controller, a command torque for each power source reflecting the intervention torque; determining, by the controller, a requested torque to be monitored based on vehicle operating information; determining, by the controller, a compensation value for each power source taking into account the intervention torque based on i) the command torque of each power source after reflecting the intervention torque and ii) the distributed command torque of each power source before reflecting the intervention torque; limiting, by the controller, the compensation value for each power source to a corresponding drive system limit value among the respective drive system limit values ​​for the power source; determining, by the controller, a command torque limit value for each power source using a corresponding limit offset value and a request torque to be monitored; as well as Whether there is an abnormality in determining the command torque of each power source is determined by the controller based on a comparison of the command torque limit value and the sum of the command torques of the power sources.

2. The method according to claim 1, wherein: Limiting the compensation value to a corresponding drive system limit value for each power source includes: subtracting the command torque of the power source before reflecting the intervention torque from the command torque of the power source after reflecting the intervention torque to determine a compensation value for the power source; and The compensation value of the power source is limited using the corresponding drive system limit value.

3. The method according to claim 2, wherein: Determining the command torque limit value includes: determining a total compensation value by summing the limit compensation values ​​for the power sources; and The commanded torque limit value is determined using the total compensation value and the requested torque to be monitored.

4. The method according to claim 3, wherein: Determining a commanded torque limit value includes determining the commanded torque limit value by adding the total compensation value to a requested torque to be monitored.

5. The method according to claim 2, wherein: The power source includes i) an engine and an electric motor configured to drive the hybrid vehicle; and ii) a hybrid starter generator HSG connected to the engine to deliver power to start the engine or to generate electricity using the engine power.

6. The method according to claim 5, wherein: The drive system limit value includes an engine system limit value, a motor system limit value and an HSG system limit value, and wherein the engine system limit value is determined based on an engine speed and a driving mode, and the motor system limit value and the HSG system limit value are charging and discharging limit values ​​determined based on a state of charge (SOC) of a main battery.

7. The method according to claim 1, wherein: The power source includes i) an engine and an electric motor configured to drive the hybrid vehicle; and ii) a hybrid starter generator HSG connected to the engine to deliver power to start the engine or to generate electricity using the engine power.

8. The method according to claim 1, wherein: Determining the command torque limit value includes determining the command torque limit value using a value obtained by adding the limit compensation value to the request torque to be monitored.

9. The method according to claim 1, wherein: Determining whether there is an anomaly in determining the commanded torque of each power source includes: determining that there is an abnormality in determining the command torque of each power source when the command torque limit value is equal to or less than the sum of the command torques of each power source; and When the command torque limit value is greater than the sum of the command torques of each power source, it is determined that the determination of the command torque of each power source is normal.

10. A system for monitoring torque in a hybrid vehicle, the system comprising: a controller configured to determine a driver requested torque and a driving mode of the hybrid vehicle, distributing the driver requested torque to each of the power sources in the hybrid vehicle based on the driving mode, adding the intervention torque to the allocated driver requested torque for each power source, to determine a command torque for each power source reflecting the intervention torque, determining a requested torque to be monitored based on vehicle operating information, Based on the command torque determined for each power source after reflecting the intervention torque and the distributed command torque for each power source before reflecting the intervention torque, determining a compensation value for each power source taking into account the intervention torque, Limiting the determined compensation value to the drive system limit value, determining a command torque limit value using the limited offset value and the determined requested torque to be monitored, and Based on a comparison of the determined command torque limit value and the sum of the command torques of the power sources, it is determined whether there is an abnormality in determining the command torque of each of the power sources.

11. The system according to claim 10, wherein: The controller is configured to: subtracting a command torque of each power source before reflecting the intervention torque from a command torque of each power source after reflecting the intervention torque to determine a compensation value for each power source; as well as The determined compensation value for each power source is limited using a corresponding one of the power source's respective power system values.

12. The system according to claim 11, wherein: The controller is configured to: A total compensation value is determined by summing the compensation values ​​of the limits of each power source, and the command torque limit value is determined using the determined total compensation value and the request torque to be monitored.

13. The system according to claim 12, wherein: The controller is configured to determine the commanded torque limit value by adding the total compensation value to a requested torque to be monitored.

14. The system according to claim 11, wherein: The power source includes i) an engine and an electric motor configured to drive the vehicle; and ii) a hybrid starter generator HSG connected to the engine to deliver power to start the engine or to generate electricity using the engine power.

15. The system of claim 14, wherein: The drive system limit values ​​include an engine system limit value, a motor system limit value and an HSG system limit value, and wherein: The engine system limit value is determined based on an engine speed and a driving mode, and the motor system limit value and the HSG system limit value are charge and discharge limit values ​​determined based on a state of charge (SOC) of a main battery.

16. The system of claim 10, wherein: The power source includes i) an engine and an electric motor configured to drive the vehicle; and ii) a hybrid starter generator (HSG) connected to the engine to deliver power to start the engine or to generate electricity using the engine power.

17. The system according to claim 10, wherein: The controller is configured to determine the command torque limit value using a value obtained by adding a limited compensation value to a request torque to be monitored.

18. The system of claim 10, wherein: The controller is configured to: determining that there is an abnormality in determining the command torque of each power source when the command torque limit value is equal to or less than the sum of the command torques of the power sources; as well as When the command torque limit value is greater than the sum of the command torques of the respective power sources, it is determined that the determination process of the command torque of each power source is normal.

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