Torque monitoring system and method for hybrid electric vehicle

Abstract

A torque monitoring system and method of a hybrid electric vehicle are provided to accurately monitor and diagnose compensation torques in addition to driver demand torques, such as intervention torques and engine friction torques generated from the angle of the vehicle. The torque monitoring system includes a control unit configured to: determine a final commanded torque for each power source; determining a monitoring request torque based on the vehicle driving information; based on the intervention torque of each power source and the additional torque of each power source, determining a compensation torque of each power source according to whether an engine clutch is engaged; determining a command torque limit; and determining whether there is an abnormality in each torque determination process based on the determined command torque limit value and the determined sum of the final command torques of the respective power sources.

Description

Technical Field

[0001] The present disclosure relates to a torque monitoring system and method for a hybrid electric vehicle, which can accurately diagnose whether there are abnormalities in torque determination and command generation. Background Art

[0002] A hybrid electric vehicle is a vehicle that travels using an engine (i.e., an internal combustion engine) and an electric motor as power sources. As one type of the powertrain of a hybrid electric vehicle, a transmission-mounted electric device (TMED) type hybrid system is known.

[0003] In the TMED type hybrid system, an engine clutch is placed between the engine and the electric motor, the engine and the electric motor are devices for driving the vehicle, and a transmission is connected to the output side of the electric motor. In addition, an inverter for driving and controlling the electric motor is installed in the vehicle. The electric motor is connected to a high-voltage main battery in the vehicle through the inverter so as to be rechargeable and dischargeable.

[0004] The inverter converts direct current (DC) supplied from the battery into alternating current (AC), and applies the AC to the electric motor through a power cable when driving the electric motor. In addition, the inverter converts the AC generated by the electric motor into DC and supplies the DC to the battery when regenerating the electric motor.

[0005] In addition, the electric motor as a starter generator is connected to the engine so as to always transmit power. The electric motor uses the rotational force transmitted from an engine (i.e., a hybrid starter generator (HSG)) provided in the vehicle to start the engine or generate power. The HSG is also a type of electric motor, and can operate as both an electric motor and a generator like the electric motor for driving the vehicle (i.e., the drive motor). The HSG is connected to the battery through the inverter so as to be rechargeable and dischargeable.

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

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

[0008] Figure 1 is a block diagram showing the configuration of a control device that performs power control and shift control of a hybrid electric vehicle. As Figure 1As shown, in a hybrid electric vehicle, multiple control units 10 - 40 perform cooperative control to achieve power control and shift control of the vehicle.

[0009] First, a hybrid control unit (HCU) 10, which is called a high - level control unit, determines a driver - required torque depending on the driver's driving intention based on vehicle driving information such as the driver's accelerator pedal input value (APS value), brake pedal input value (BPS value), and vehicle speed.

[0010] Among the driver's driving input values, the accelerator pedal input value can be detected by an accelerator position sensor (APS), and the brake pedal input value can be detected by a brake pedal position sensor (BPS).

[0011] In addition, the hybrid control unit (HCU) 10 determines an engine on - or - off mode that satisfies the driver - required torque (i.e., determines the driving mode), and based on the determined driver - required torque and engine on / off mode information, performs torque distribution to the drive device.

[0012] The hybrid control unit 10 determines an engine torque and a motor torque that satisfy the driver - required torque according to the distribution ratio and distributed torque distribution for power transmission. Then, the hybrid control unit 10 generates and outputs torque commands for each power source.

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

[0014] Shift control is performed together with the above - mentioned power control of the vehicle, and a transmission control unit (TCU) 40 determines a target gear based on information collected from the vehicle, and controls the operation of the transmission to perform a shift to the target gear.

[0015] The transmission control unit 40 provides current shift state information (such as the target gear, shift level, and shift stage) to the hybrid control unit 10. The hybrid control unit 10 performs torque intervention control, etc., with reference to the shift state information.

[0016] This hybrid control unit (HCU), which is the upper - layer control unit in a conventional TMED vehicle or a vehicle domain control unit (VDCU), has a structure that cannot detect a situation where the torque is excessive compared to the driver's requirements. This defect may occur due to an error in software or hardware in the basic control logic, which is responsible for determining the torque of each power source (engine, motor, and HSG) and generating commands for each power source.

[0017] Therefore, a torque monitoring logic for monitoring torque determination and command generation of the basic control logic has been developed and is known. In addition, efforts are being made to apply the torque monitoring logic to vehicles to ensure safe acceleration and deceleration of the vehicle level.

[0018] When applying the torque monitoring logic, as described above, due to the limitations of the microcontroller, the basic control logic is simplified, and torque determination and instruction generation monitoring are performed on the simplified basic control logic.

[0019] However, according to the known torque monitoring logic, by receiving the torque command value from the basic control logic, errors may occur during the process of diagnosing abnormalities, such as torque determination errors, command generation errors, and hardware failures in the basic control logic. As a result, there is a problem of misdiagnosing abnormalities.

[0020] For example, external intervention torques regarding gear shifting, active shift control (ASC), and traction control system (TCS) received from other control units should be reflected in the torque distribution logic, which determines the final torque command value for each power source (i.e., engine, motor, and HSG). However, when an error occurs during the process of reflecting the external intervention torque, even if an error occurs in the basic control logic, the vehicle may be misdiagnosed as a normal state.

[0021] Generally, the control unit of a vehicle determines the driver's desired torque based on the driver's accelerator pedal input value and the driver's brake pedal input value, and this torque is called the driver demand torque.

[0022] However, in addition to the driver's desired torque, there are separate torques that exist as the torques of the vehicle. For example, in order to ensure the driving performance and safety of the vehicle, there are separate torques required by the transmission control unit (TCU), traction control system (TCS), chassis control unit, etc., and these torques are called intervention torques.

[0023] In addition, due to the nature of a hybrid electric vehicle, when the engine temporarily does not generate an output torque relative to the commanded torque, additional torque should be added to or subtracted from the engine's output torque by the motor. In addition, the engine friction torque should also be considered.

[0024] When controlling the torque for driving a vehicle, it is desired to detect the occurrence of the above-mentioned separate torques in addition to the driver demand torque, and confirm whether these torques are normal to prevent excessive torque from being generated in the vehicle.

[0025] 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 include information that does not constitute the prior art known to those of ordinary skill in the art in this country. Summary of the Invention

[0026] The present disclosure has been dedicated to solving the above problems related to the prior art. The object of the present disclosure is to provide a torque monitoring system and method for a hybrid electric vehicle that can accurately diagnose whether there are abnormalities in torque determination and command generation in the basic control logic. In addition, another object of the present disclosure is to provide a torque monitoring system and method for a hybrid electric vehicle that can accurately monitor and diagnose compensation torques other than the driver-requested torque, such as intervention torque generated from the perspective of the vehicle and engine friction torque.

[0027] The object of the present disclosure is not limited to the above objects, and those of ordinary skill in the art to which the present disclosure pertains (referred to as "those skilled in the art") should clearly understand other objects not mentioned herein from the following description.

[0028] In one aspect, the present disclosure provides a torque monitoring method for a hybrid electric vehicle. The method includes: determining the final command torque of each power source by adding the intervention torque of each power source and the additional torque of each power source for torque compensation to the command torque of each power source allocated according to the driver-requested torque by a control unit. The method further includes: determining a monitored required torque by the control unit based on vehicle driving information; and determining the compensation torque of each power source by the control unit based on the intervention torque of the power source and the additional torque of each power source according to whether the engine clutch is engaged. The method also includes determining a command torque limit value by the control unit, which is the sum of the determined monitored required torque and the determined compensation torque of each power source. Additionally, the method includes determining by the control unit whether there is an abnormality in the torque determination process during each operation based on the sum of the determined final command torques of each power source and the determined command torque limit value.

[0029] In another embodiment, each intervention torque of each power source may include: an internal intervention torque, which is internally determined by the control unit to control vehicle movement; and an external intervention torque received from the outside.

[0030] In another embodiment, the intervention torque of each power source may include an engine intervention torque and a motor intervention torque.

[0031] In yet another embodiment, the compensation torque of each power source may include an engine compensation torque and a motor compensation torque. The additional torque of each power source may include an additional engine torque and an additional motor torque. In a disengaged state of the engine clutch, the motor compensation torque may be determined as the sum of the motor intervention torque and the additional motor torque, and the engine compensation torque may be determined to be zero.

[0032] In yet another embodiment, the compensation torque of each power source may include an engine compensation torque and a motor compensation torque. The additional torque of each power source may include an additional engine torque and an additional motor torque. Further, in an engaged state of the engine clutch, the motor compensation torque may be determined as the sum of the motor intervention torque and the additional motor torque, and the engine compensation torque may be determined as the sum of the engine intervention torque and the additional engine torque.

[0033] In yet another embodiment, the additional torque of each power source may include an additional engine torque and an additional motor torque. The additional engine torque may be determined as the engine friction torque, and the additional motor torque may be determined as the motor torque that compensates for a decrease or an increase in the engine output.

[0034] In another embodiment, the compensation torque of each power source may include an engine compensation torque and a motor compensation torque. The commanded torque limit value may be determined as the sum of the monitored required torque, the engine compensation torque, and the motor compensation torque.

[0035] In yet another further embodiment, in determining whether there is an abnormality in the torque determination process for each operation, the control unit may be configured to diagnose that there is an abnormality in the torque determination process for each operation when the absolute value of the difference between the commanded torque limit value and the sum of the determined final commanded torques of each power source is greater than or equal to a predetermined set value. Further, the controller may be configured to diagnose that the torque determination process for each operation is normal when the absolute value of the difference between the commanded torque limit value and the sum of the determined final commanded torques of each power source is less than the predetermined set value.

[0036] In another aspect, the present disclosure provides a torque monitoring system for a hybrid electric vehicle. The torque monitoring system includes a control unit configured to, when a driver demand torque is determined and a driving mode of the vehicle is determined: determine commanded torques of respective power sources based on the driver demand torque by allocating the driver demand torque according to the driving mode; and determine final commanded torques of the respective power sources by adding an intervention torque of each power source and an additional torque of each power source for torque compensation to the determined commanded torque of each power source. The control unit is further configured to: determine a monitored demand torque based on vehicle driving information; determine a compensation torque of each power source based on the intervention torque of each power source and the additional torque of each power source according to whether an engine clutch is engaged; determine a commanded torque limit value, which is a sum of the determined monitored demand torque and the determined compensation torque of each power source; and determine whether there is an abnormality in each torque determination process based on a sum of the determined commanded torque limit value and the determined final commanded torque of each power source.

[0037] In an embodiment, each intervention torque of each power source may include: an internal intervention torque determined internally by the control unit to control vehicle movement; and an external intervention torque received from the outside.

[0038] In another embodiment, the intervention torque of each power source may include an engine intervention torque and a motor intervention torque.

[0039] In yet another embodiment, the compensation torque of each power source may include an engine compensation torque and a motor compensation torque. The additional torque of each power source may include an additional engine torque and an additional motor torque. In a disengaged state of the engine clutch, the motor compensation torque may be determined as a sum of the motor intervention torque and the additional motor torque, and the engine compensation torque may be determined as zero.

[0040] In yet another embodiment, the compensation torque of each power source may include an engine compensation torque and a motor compensation torque. The additional torque of each power source may include an additional engine torque and an additional motor torque. In an engaged state of the engine clutch, the motor compensation torque may be determined as a sum of the motor intervention torque and the additional motor torque, and the engine compensation torque may be determined as a sum of the engine intervention torque and the additional engine torque.

[0041] In yet another embodiment, the control unit may include a basic control logic unit configured to: determine a driver required torque; determine a driving mode of the vehicle; determine a commanded torque of each power source based on the driver required torque; and determine a final commanded torque of each power source. The control unit may further include a torque monitoring logic unit configured to: determine a monitored required torque; determine the compensation torque of each power source according to whether the engine clutch is engaged; determine the commanded torque limit value; and determine whether there is an abnormality in each torque determination process.

[0042] In another embodiment, the torque monitoring logic unit may be configured to receive information from the basic control logic unit, the information including: the commanded torque of each power source based on the driver required torque; the commanded torque of each power source obtained by adding the intervention torque of each power source to the commanded torque of each power source based on the driver required torque after reflecting the intervention torque of each power source; the additional torque of each power source for torque compensation; the final torque command of each power source; and the hybrid electric vehicle driving mode. The torque monitoring logic unit may be configured to use the received information to determine the compensation torque and the commanded torque limit value of each power source.

[0043] In another embodiment, the intervention torque of each power source may include an engine intervention torque and a motor intervention torque. The torque monitoring logic unit may be configured to determine the engine intervention torque as a value obtained by subtracting the engine commanded torque based on the driver required torque from the engine commanded torque after reflecting the intervention torque received from the basic control logic unit. In addition, the torque monitoring logic unit may be configured to determine the motor intervention torque as a value obtained by subtracting the motor commanded torque based on the driver required torque from the motor commanded torque after reflecting the intervention torque received from the basic control logic unit.

[0044] In yet another embodiment, the additional torque of each power source may include an additional engine torque and an additional motor torque.

[0045] In yet a further embodiment, the additional engine torque may be determined as the engine friction torque. The additional motor torque may be determined as the motor torque for compensating for a decrease or increase in the engine output.

[0046] In yet another embodiment, the compensation torque of each power source may include an engine compensation torque and a motor compensation torque. The commanded torque limit value may be determined as the sum of the monitored required torque, the engine compensation torque, and the motor compensation torque.

[0047] In yet another embodiment, the control unit may be configured to diagnose an abnormality in each torque determination process when the absolute value of the difference between the commanded torque limit value and the sum of the determined final commanded torques of the respective power sources is greater than or equal to a predetermined set value. The control unit may also be configured to diagnose that each torque determination process is normal when the absolute value of the difference between the commanded torque limit value and the sum of the determined final commanded torques of the respective power sources is less than the predetermined set value.

[0048] Other aspects and embodiments of the present disclosure are discussed below.

[0049] The above and other features of the present disclosure are discussed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] With reference to certain embodiments of the present disclosure shown in the drawings, the above and other features of the present disclosure are described in detail. Hereinafter, the drawings are given by way of illustration only and thus do not limit the present disclosure, and in which:

[0051] Figure 1 is a block diagram showing a configuration of a control device that performs power control and shift control of a hybrid electric vehicle;

[0052] Figure 2 is a block diagram showing a configuration of a control unit that performs torque monitoring processing according to the present disclosure; and

[0053] Figure 3 is a flowchart describing torque monitoring processing according to the present disclosure.

[0054] It should be understood that the drawings are not necessarily drawn to scale, providing a somewhat simplified representation showing various preferred features of the basic principles of the present disclosure. Specific design features of the present disclosure as disclosed herein (including, for example, specific dimensions, orientations, positions, and shapes) will be determined in part by the particular intended application and use environment.

[0055] In the drawings, reference numerals refer to the same or equivalent components of the present disclosure throughout several views of the drawings. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0056] Hereinafter, various embodiments of the present disclosure should be referred to in detail. Examples of these embodiments are shown in the drawings and described below. The specific structural or functional descriptions in the embodiments of the present disclosure set forth below are given to describe embodiments of the present disclosure, and the present disclosure may be embodied in many alternative forms. In addition, it should be understood that the present disclosure should not be construed as limited to the embodiments set forth herein, and the embodiments of the present disclosure are only provided to fully disclose the present disclosure and cover modifications, equivalents, or alternatives that fall within the scope and technical scope of the present disclosure.

[0057] In the following description of the embodiments, terms such as "first" and "second" are used only to describe various elements, and these elements should not be construed as being limited by these terms. These terms are only used to distinguish one element from other elements. For example, without departing from the scope of the present disclosure, the first element described below may be referred to as the second element, and similarly, the second element described below may be referred to as the first element.

[0058] When an element or layer is referred to as being "connected to" or "coupled to" another element or layer, it may be directly connected to or coupled to the other element or layer, or there may be intervening elements or layers. In contrast, when an element or layer is referred to as being "directly connected to" or "directly coupled to" another element or layer, there may be no intervening elements or layers. Other words used to describe the relationship between elements should be interpreted in a similar manner, for example, "between" and "directly between", "adjacent" and "directly adjacent", etc.

[0059] As long as feasible, the same reference numerals will be used throughout the drawings to refer to the same or similar components. The terms used herein are for the purpose of describing particular embodiments only and are not intended to be limiting. As used herein, unless the context clearly indicates otherwise, the singular forms may also be intended to include the plural forms. The terms "comprises", "comprising", "includes" and "having" are inclusive and thus specify the presence of the stated features, wholes, operations, acts, elements, components and / or combinations thereof, but do not preclude the presence or addition of one or more other features, wholes, operations, acts, elements, components and / or combinations thereof.

[0060] When a controller, component, device, element, part, unit, module, etc. of the present disclosure is described as having a purpose or performing an operation, function, etc., the controller, component, device, element, part, unit or module should be regarded herein as "configured to" meet that purpose or perform that operation or function. Each controller, component, device, element, part, unit, module, etc. may individually embody a processor and a memory (such as a non-transitory computer-readable medium) or be included together with the processor and the memory as part of a device.

[0061] The present disclosure provides a torque monitoring system and method for a hybrid electric vehicle that can accurately diagnose whether there is an abnormality in torque determination and command generation. Specifically, the present disclosure provides a system and method that can perform accurate torque monitoring and detect excessive torque. Specifically, the present disclosure provides a system and method that can prevent false diagnosis caused by errors in the process of reflecting compensation torque.

[0062] Figure 2is a block diagram showing the configuration of a control unit that performs a torque monitoring process according to the present disclosure, and also shows components that execute basic control logic. In addition, Figure 3 is a flowchart describing the torque monitoring process according to the present disclosure. Figure 3 represents a method for both the torque command generation process for each power source in the basic control logic and the torque monitoring process in the torque monitoring logic executed by the control unit 100.

[0063] As Figure 2 shown, the control unit 100 that performs the torque monitoring process according to the present disclosure includes a first processor (the "basic control logic unit" in Figure 2 ) 110, which is configured to execute the basic control logic for torque determination and command generation of each power source. In addition, the control unit 100 includes a second processor (the "torque monitoring logic unit" in Figure 2 ) 120, which is configured to execute the torque monitoring logic for torque monitoring and error detection.

[0064] By Figure 2 configuration, in the basic control logic, when an error occurs in the torque distribution logic, the situation can be diagnosed in the torque distribution logic, and the torque distribution logic is configured to, after the driver demand torque is distributed as the torque (command torque) of each power source, determine the torque of each power source obtained by adding a compensation torque (such as an intervention torque of each power source and an additional torque of each power source) to the distributed torque of each power source after reflecting the compensation torque, and an over-command torque occurs.

[0065] In the present disclosure, the control unit 100 executes a basic control process for generating torque commands for each power source and a torque monitoring process for monitoring torque and performing fault diagnosis. The control unit 100 may be a hybrid control unit (HCU) as a high-level control unit or a vehicle domain control unit (VDCU) in which multiple control units are integrated.

[0066] The control unit 100 is installed on a hybrid electric vehicle and is responsible for controlling the torque of the vehicle drive system according to the driver's requirements. The control unit 100 is also responsible for monitoring whether the torque value corresponding to the commanded output of each power source is reliable.

[0067] As shown in the figure, the control unit 100 includes a first processor (hereinafter referred to as the "basic control logic unit") 110 configured to execute basic control logic. The basic control logic unit 110 includes a driving information receiver 111, a demanded torque determiner 112, a driving mode determiner 113, an internal intervention calculator 114, an external intervention calculator 115, a torque compensator 116, and a torque distributor 117.

[0068] The driving information receiver 111 of the control unit 100 receives vehicle driving information detected by a driving information detector (not shown) or another control unit. The driving information detector may include: an acceleration position sensor (APS) that detects the driver's accelerator pedal input value (APS value); a brake pedal position sensor (BPS) that detects the driver's brake pedal input value (BPS value); and a vehicle speed sensor that detects the vehicle speed.

[0069] The vehicle driving information detected by the driving information detector is information indicating the vehicle driving state, and includes the driver's accelerator pedal input value (APS value), the driver's brake pedal input value (BPS value), and the vehicle speed.

[0070] The vehicle speed sensor may be a wheel speed sensor, and it is a well-known technique to obtain vehicle speed information from signals from the wheel speed sensor, and its detailed description is omitted.

[0071] The required torque determiner 112 determines the driver's required torque from the vehicle driving information received through the driving information receiver 111. That is, the required torque determiner 112 determines the driver's required torque according to the vehicle driving information including the driver's accelerator pedal input value (APS value), brake pedal input value (BPS value), etc. (pedal input values) and the vehicle speed, according to the driver's driving intention.

[0072] The driving mode determiner 113 determines the driving mode (powertrain (PT) mode), such as a hybrid electric vehicle (HEV) mode, an electric vehicle (EV) mode, etc., based on the determined driver's required torque and charge / discharge related information (such as charging and discharging strategies depending on the battery state).

[0073] In addition, before the torque distributor 117 performs torque distribution, the process of determining the intervention torque by the internal intervention calculator 114 and the external intervention calculator 115, and the process of determining the compensation torque by the torque compensator 116 are executed.

[0074] Before the control unit 100 determines the final command torque of each power source, there are interventions that are processed internally to control the vehicle movement. For example, the electronic ride function of minimizing vehicle sway and providing a comfortable ride by adjusting the torque of the motor when the vehicle passes over a bump (i.e., a speed bump) or accelerates, the electronic processing function of increasing steering response and turning stability by accelerating and decelerating to move the center of gravity when entering and leaving a curve, and the electric dynamic torque vectoring control (e-DTVC) function that realizes torque vector distribution. Internal torque interventions are executed to provide these functions.

[0075] Torque intervention can be performed by determining an intervention torque and reflecting the determined intervention torque in the command torque of each power source allocated by the control unit 100 according to the driver's required torque. The internal intervention calculator 114 of the control unit 100 determines the internal intervention torque for vehicle motion control independently of the driver's required torque as described above.

[0076] In addition, the control unit 100 receives an intervention torque from other external control units (such as a transmission control unit (TCU), a traction control system (TCS), a chassis control unit, etc.). The external intervention calculator 115 processes the intervention torque received from other control units and determines the final external intervention torque by reflecting the intervention torque in the command torque of each power source allocated according to the driver's required torque (the command torque of each power source based on the driver's required torque).

[0077] In the present disclosure, the internal intervention torque and the external intervention torque can be obtained for each power source installed in the vehicle. In addition, for each power source, the additional torque described below in the present invention can also be obtained. The power source may include an engine and an electric motor, which are devices configured to drive the vehicle; and a hybrid starter generator (HSG) directly connected to the engine to transmit power to it.

[0078] In addition, in the present disclosure, the torque compensator 116 of the control unit 100 compares the calculated engine torque value with the actual engine torque value, and when the calculated engine torque value is less than or exceeds the actual engine torque value, calculates the torque that needs to be compensated by the electric motor. In addition, the torque compensator 116 calculates the engine friction torque, which is an additional torque for engine torque compensation, independently of the torque that needs to be compensated by the electric motor.

[0079] In other words, the torque compensator 116 of the control unit 100 determines the additional torque of each power source for torque compensation, such as the electric motor torque for compensation ( Figure 3 "additional electric motor torque" in Figure 3 and the engine friction torque (

[0080] "additional engine torque" in Figure 3The "additional motor torque" (in [description]) is the motor torque used to compensate for the decrease or increase in the engine output. For example, when the engine starts, the engine torque is initially not as much as the command (engine torque command) from the higher-level control unit (such as HCU). Therefore, the torque shortage is handled by the motor. The torque shortage handled by the motor becomes the motor torque for compensation. That is, even if 100 Nm of engine torque is required at the start of engine startup, but in fact, when the engine only generates 60 Nm of engine torque, the motor must additionally supply 40 Nm of torque.

[0081] In the present disclosure, the intervention torque of each power source includes the internal intervention torque for the engine, the external intervention torque for the engine, the internal intervention torque for the motor, and the external intervention torque for the motor. In addition, the additional torque of each power source for compensation includes the above-mentioned engine friction torque and the motor torque used to compensate for the decrease or increase in the engine output.

[0082] In addition, in the present disclosure, the sum of the intervention torque of each power source and the additional torque of each power source is defined as the compensation torque of each power source. In addition, the sum of the internal intervention torque of the engine, the external intervention torque of the engine, and the additional engine torque such as the engine friction torque is defined as the engine compensation torque. In addition, the motor compensation torque is defined as the sum of the internal intervention torque of the motor, the external intervention torque of the motor, and the additional motor torque (such as the motor torque used to compensate for the decrease or increase in the engine output).

[0083] In the present disclosure, not only the driver-requested torque is monitored and diagnosed, but also the intervention torque of each power source determined in the basic control logic unit, the additional torque of each power source for compensation, and the compensation torque of each power source. In addition, the calculation process and method, application purpose, function, effect, etc. of the compensation torque (such as the above-mentioned internal intervention torque, external intervention torque, engine friction torque, and motor torque) for compensating the decrease or increase in the engine output are well known. Therefore, its detailed description has been omitted in this specification.

[0084] The torque distributor 117 of the control unit 100 executes the torque distribution logic based on the driving mode determined by the driving mode determiner 113. According to the torque distribution logic, the driver-requested torque is distributed to each power source depending on the driving mode to determine the command torque of each power source, that is, the engine torque, the motor torque, and the HSG torque. The engine torque, the motor torque, and the HSG torque are the command torques of each power source before reflecting the internal and external intervention torques and the additional torques for compensation (that is, the command torques of each power source before reflecting the compensation torque).

[0085] In addition, the torque distributor 117 of the control unit 100 determines the final command torque of each power source (i.e., the command torque of each power source after reflecting the compensation torque) by adding the compensation torque of each power source to the determined command torque of each power source. The compensation torque of each power source is a torque that is the sum of the internal intervention torque of each power source, the external intervention torque of each power source, and the additional torque of each power source.

[0086] According to the driving mode (PT mode), only when the engine clutch is engaged so that power transmission can occur between the engine and the electric motor, the internal intervention torque of the engine, the external intervention torque of the engine, and additional engine torques such as engine friction torque are identified and added to the engine command torque.

[0087] When the engine clutch is disengaged so that power transmission is not enabled, the engine torque is not transmitted to the wheels. Accordingly, it is not necessary to reflect and use the internal intervention torque of the engine, the external intervention torque of the engine, and the additional engine torque. At this time, the engine compensation torque that is the sum of the internal intervention torque of the engine, the external intervention torque of the engine, and the additional engine torque may be zero (0 Nm).

[0088] This is the same in the second processor (hereinafter referred to as the "torque monitoring logic unit") 120 described below. In the engaged state of the engine clutch, the total compensation value of the command torque limit value determined by the command torque limit value determiner 122 of the torque monitoring logic unit 120 is the sum of the following: the electric motor intervention torque, which is the total intervention torque of the electric motor (drive electric motor); the engine intervention torque, which is the total intervention torque for the engine; the electric motor torque that compensates for a decrease or increase in the engine output (i.e., additional electric motor torque); and the engine friction torque (i.e., additional engine torque).

[0089] In the disengaged state of the engine clutch, the total compensation value of the command torque limit value is the sum of only the electric motor intervention torque and the electric motor torque that compensates for a decrease or increase in the engine output (i.e., additional electric motor torque or electric motor compensation torque). At this time, the engine compensation torque that is the sum of the engine intervention torque and the engine friction torque (i.e., additional engine torque) becomes 0 Nm.

[0090] When the final command torque of each power source obtained by reflecting the compensation torque of each power source in the command torque of each power source based on the driver's required torque is determined, the torque distributor 117 of the control unit 100 generates and outputs the torque command of each power source to control the operation of each power source. This is achieved so as to generate and apply a torque corresponding to the determined final command torque of each power source. Accordingly, the operation of each power source can be controlled based on the final torque command of each power source generated and output by the control unit 100.

[0091] The command torque of each power source based on the driver's required torque includes Figure 3 the "motor command torque based on the driver's required torque" and the "engine command torque based on the driver's required torque" in

[0092] In addition, in the present disclosure, information such as the command torque of each power source determined by allocating the driver's required torque (command torque based on the driver's required torque), the command torque of each power source after reflecting internal and external intervention torques, the engine friction torque, the motor torque for compensating for a decrease or increase in engine output, and the final torque command of each power source is transmitted to the torque monitoring logic unit 120 in real time. In addition, the driving mode of the vehicle determined during the process of executing the basic control logic is transmitted to the torque monitoring logic unit 120 in real time.

[0093] The control unit 100 executes the torque monitoring logic simultaneously with the basic control logic. For this purpose, the control unit 100 further includes a component for executing the torque monitoring logic, that is, the torque monitoring logic unit 120.

[0094] In the present disclosure, variables such as the pedal input value (APS value, BPS value), vehicle speed, etc., the memory, tasks, setting data (table) for setting adjustment values of each variable (correction variable), etc. are allocated and used independently of each other. These variables are used in the calculation of monitoring torque in the torque monitoring logic unit 120 and the calculation of torque in the basic control logic 110.

[0095] In addition, the torque monitoring logic unit 120 can also monitor whether excessive torque detection and determination are not appropriately performed. In other words, when the torque monitoring logic unit 120 does not appropriately detect and determine excessive torque, it is difficult to monitor the basic control logic.

[0096] In the present disclosure, the torque monitoring logic unit 120 of the control unit 100 may include a required torque determiner 121, a command torque limit value determiner 122, a command torque summator 123, a command torque consistency determiner 124, a fault diagnostician 125, and a fail-safe controller 126.

[0097] The monitoring required torque determiner 121 determines the driver required torque based on vehicle driving information including driving input values (pedal input values) such as the accelerator pedal input value (APS value) and the brake pedal input value (BPS value). Additionally, the monitoring required torque determiner 121 determines the driver required torque based on the vehicle speed in the same manner as the required torque determiner 112 of the basic control logic unit 110, but uses a required torque determination process that is a simplified version of the required torque determination process of the basic control logic to determine the monitored required torque. The driver required torque determined by the monitoring required torque determiner 121 is defined as the monitored required torque.

[0098] As an example, the required torque determiner 112 of the basic control logic unit 110 determines the driver required torque corresponding to vehicle driving variables such as the driver's pedal input values (APS value, BPS value) and the vehicle speed. Additionally, the required torque determiner 112 of the basic control logic unit 110 determines the currently selected driving mode using setting data (a table for each driving mode) for each driving mode (economy mode, normal mode, sport mode, etc.), but the monitoring required torque determiner 121 of the torque monitoring logic unit 120 determines the driver required torque corresponding to the vehicle driving variables using one set of setting data regardless of the driving mode.

[0099] When the monitored required torque is determined by a simplified process of the driver required torque determination process of the basic control logic, as described above, the commanded torque limit value determiner 122 determines the commanded torque limit value by adding the total compensation value (the sum of the compensation values of each power source) to the determined monitored required torque. The compensation value is a value that takes into account torque intervention and torque compensation.

[0100] Therefore, the commanded torque limit value determiner 122 receives in real time from the basic control logic unit 110 the commanded torque of each power source determined by allocating the driver required torque based on the driver required torque. In Figure 3 this, the "motor commanded torque based on the driver required torque" and the "engine commanded torque based on the driver required torque" are the commanded torques of each power source determined by allocating the driver required torque.

[0101] Additionally, the commanded torque limit value determiner 122 receives in real time information such as the commanded torque of each power source after reflecting internal and external intervention torques, the engine friction torque, the motor torque for compensating for a decrease or increase in engine output, the final commanded torque of each power source, the driving mode of the vehicle, etc.

[0102] The command torque of each power source after reflecting internal and external intervention torques includes the motor command torque after reflecting internal and external intervention torques and the engine command torque after reflecting internal and external intervention torques.

[0103] In addition, the motor command torque after reflecting internal and external intervention torques is the sum of the motor command torque based on the driver's required torque and the internal and external intervention torques of the motor. In addition, the engine command torque after reflecting internal and external intervention torques is the sum of the engine command torque based on the driver's required torque and the internal and external intervention torques of the engine.

[0104] In addition, as Figure 3 shown, the command torque limit value determiner 122 determines the motor intervention torque, the additional motor torque, the engine intervention torque, and the additional engine torque. The motor intervention torque can be determined as the value obtained by subtracting the motor command torque based on the driver's required torque from the motor command torque after reflecting internal and external intervention torques (S11). In addition, the additional motor torque can be determined as the motor torque for compensating for the decrease or increase in engine output (S12).

[0105] In addition, the engine intervention torque can be determined as the value obtained by subtracting the engine command torque based on the driver's required torque from the engine command torque after reflecting internal and external intervention torques (S13). In addition, the additional engine torque can be determined as the engine friction torque (S14).

[0106] To detect abnormal torques such as excessive torque, the difference between the command torque of each power source reflecting both intervention torque and external torque and the command torque of each power source not reflecting both intervention torque and external torque is used to determine the intervention torque of each power source.

[0107] After that, the command torque limit value determiner 122 confirms whether the engine clutch is engaged (S15). This is achieved to determine whether the intervention torque of the motor and the additional motor torque for compensation will be used, or whether both the intervention torques of the motor and the engine and the additional motor torque for compensation and the additional engine torque for compensation will be used to determine whether the engine clutch is engaged. When the engine clutch is not engaged, the engine torque does not affect the overall torque of the vehicle.

[0108] The command torque limit value determiner 122 determines the final compensation torque. The final compensation torque includes the motor compensation torque and the engine compensation torque. In addition, when the engine clutch is disengaged, the motor compensation torque is determined as the sum of the motor intervention torque and the additional motor torque, and the engine compensation torque is determined as zero (0 Nm) (S16).

[0109] When the engine clutch is engaged, the motor compensation torque is determined as the sum of the motor intervention torque and the additional motor torque, and the engine compensation torque is determined as the sum of the engine intervention torque and the additional engine torque (S17).

[0110] Thereafter, the command torque limit value determiner 122 finally determines the command torque limit value by adding the monitored required torque determined by the monitored required torque determiner 121, the motor compensation torque, and the engine compensation torque (S18).

[0111] Thereafter, the command torque summing unit 123 of the torque monitoring logic unit 120 sums the final command torques of the respective power sources received from the basic control logic unit 110 (values reflecting the internal and external intervention torques and the additional torques for compensation). The command torque consistency determiner 124 determines the consistency of the command torque by comparing the command torque limit value determined by the command torque limit value determiner 122 with the sum of the final command torques of the respective power sources determined by the command torque summing unit 123 (S19).

[0112] When the absolute value of the difference between the command torque limit value determined by the command torque limit value determiner 122 and the sum of the final command torques of the respective power sources determined by the command torque summing unit 123 is greater than or equal to a set value predetermined as a margin value, the fault diagnostician 125 determines that there is an abnormality in the command torque and a fault exists (i.e., an error in the torque distribution logic, etc.) (S20). The fail-safe controller 126 allows the electric vehicle to enter the fail-safe mode and then performs fail-safe control (S21).

[0113] When the absolute value of the difference between the command torque limit value and the sum of the final command torques of the respective power sources is less than the set value predetermined as the margin value, the fault diagnostician 125 determines that the command torque is normal (S22).

[0114] Therefore, the torque monitoring system and method according to the present disclosure have been described in detail. According to the above torque monitoring system and method, it is possible to accurately diagnose whether there is an abnormality in torque determination and command generation in the basic control logic. In addition, in addition to the driver's required torque, it is also possible to accurately monitor and diagnose compensation torques, such as the internal and external intervention torques of the respective power sources generated from the perspective of the vehicle, the motor torque for compensating for the decrease or increase in engine output, and the engine friction torque.

[0115] In addition, when the basic control logic is diagnosed as abnormal, the electric vehicle enters the fail-safe mode. Therefore, the stability and reliability of the basic control logic can be ensured.

[0116] As is apparent from the above description, the torque monitoring system and method for a hybrid electric vehicle according to the present disclosure can accurately diagnose whether there are abnormalities in torque determination and command generation in the basic control logic. It should also be clear that, in addition to the driver-requested torque, the torque monitoring system and method for a hybrid electric vehicle can accurately monitor and diagnose compensation torques, such as internal intervention torques and external intervention torques of each power source generated from the perspective of the vehicle, motor torques for compensating for a decrease or increase in engine output, and engine friction torque.

[0117] In addition, when the basic control logic is diagnosed as abnormal, the electric vehicle enters a fail-safe mode, and thereby the stability and reliability of the basic control logic can be ensured.

[0118] The present disclosure has been described in detail with reference to embodiments of the present disclosure. However, those of ordinary skill in the art should understand that changes can be made to these embodiments without departing from the principles and spirit of the present disclosure, and the scope of the present disclosure is defined in the appended claims and their equivalents.

Claims

1. A torque monitoring method for a hybrid electric vehicle, the torque monitoring method comprising: determining, by a control unit, a final command torque of each power source by adding an intervention torque of each power source and an additional torque of each power source for torque compensation to a command torque of each power source allocated according to a driver demand torque; determining, by the control unit, a monitored demand torque based on vehicle driving information; determining, by the control unit, a compensation torque of each power source based on the intervention torque and the additional torque according to whether an engine clutch is engaged; determining, by the control unit, a command torque limit value, which is a sum of the determined demand torque and the determined compensation torque; and determining, by the control unit, whether there is an abnormality in torque determination processing at each operation based on a sum of the determined final command torques of each power source and the determined command torque limit value.

2. The torque monitoring method according to claim 1, wherein, Each intervention torque of each power source includes: an internal intervention torque, internally determined by the control unit to control vehicle movement; and an external intervention torque received from outside.

3. The torque monitoring method according to claim 2, wherein, The intervention torque of each power source includes an engine intervention torque and a motor intervention torque.

4. The torque monitoring method according to claim 3, wherein: the compensation torque of each power source includes an engine compensation torque and a motor compensation torque; the additional torque of each power source includes an additional engine torque and an additional motor torque; and in a disengaged state of the engine clutch, the motor compensation torque is determined as a sum of the motor intervention torque and the additional motor torque, and the engine compensation torque is determined to be zero.

5. The torque monitoring method according to claim 3, wherein: the compensation torque of each power source includes an engine compensation torque and a motor compensation torque; the additional torque of each power source includes an additional engine torque and an additional motor torque; and in an engaged state of the engine clutch, the motor compensation torque is determined as a sum of the motor intervention torque and the additional motor torque, and the engine compensation torque is determined as a sum of the engine intervention torque and the additional engine torque.

6. The torque monitoring method according to claim 1, wherein: the additional torque of each power source includes an additional engine torque and an additional motor torque; the additional engine torque is determined as an engine friction torque; and the additional motor torque is determined as a motor torque for compensating for a decrease or increase in engine output.

7. The torque monitoring method according to claim 1, wherein: the compensation torque of each power source includes an engine compensation torque and a motor compensation torque; and the command torque limit value is determined as a sum of the monitored demand torque, the engine compensation torque, and the motor compensation torque.

8. The torque monitoring method according to claim 1, wherein In determining whether there is an abnormality in torque determination processing at each operation, the control unit is configured to: When the absolute value of the difference between the command torque limit value and the sum of the determined final command torque is greater than or equal to a predetermined set value, it is diagnosed that there is an abnormality in the torque determination process during each operation; And When the absolute value of the difference between the command torque limit value and the sum of the determined final command torque is less than the predetermined set value, it is diagnosed that the torque determination process is normal during each operation.

9. A torque monitoring system for a hybrid electric vehicle, the torque monitoring system including a control unit, Among them, When the driver demand torque is determined and the driving mode of the hybrid electric vehicle is determined, the control unit is configured to: Allocate the driver demand torque based on the driving mode, and determine the command torque of each power source based on the driver demand torque; Determine the final command torque of each power source by adding the intervention torque of each power source and the additional torque of each power source for torque compensation to the determined command torque of each power source, Determine the monitored demand torque based on vehicle driving information; Based on the intervention torque of each power source and the additional torque of each power source, determine the compensation torque of each power source according to whether the engine clutch is engaged; Determine the command torque limit value, which is the sum of the determined demand torque and the determined compensation torque; And Based on the sum of the determined final command torque of each power source and the determined command torque limit value, determine whether there is an abnormality in each torque determination process.

10. The torque monitoring system according to claim 9, wherein, Each intervention torque of each power source includes: An internal intervention torque, which is internally determined by the control unit to control vehicle movement; and An external intervention torque received from the outside.

11. The torque monitoring system according to claim 10, wherein, The intervention torque of each power source includes an engine intervention torque and a motor intervention torque.

12. The torque monitoring system according to claim 11, wherein: The compensation torque of each power source includes an engine compensation torque and a motor compensation torque; The additional torque of each power source includes an additional engine torque and an additional motor torque; and In the disengaged state of the engine clutch, the motor compensation torque is determined as the sum of the motor intervention torque and the additional motor torque, and the engine compensation torque is determined to be zero.

13. The torque monitoring system according to claim 11, wherein: The compensation torque of each power source includes an engine compensation torque and a motor compensation torque; The additional torque of each power source includes an additional engine torque and an additional motor torque; and In the engaged state of the engine clutch, the motor compensation torque is determined as the sum of the motor intervention torque and the additional motor torque, and the engine compensation torque is determined as the sum of the engine intervention torque and the additional engine torque.

14. The torque monitoring system according to claim 9, wherein, The control unit includes: A basic control logic unit, configured to: Determine the driver demand torque, Determine the driving mode of the hybrid electric vehicle, Based on the driver demand torque, determine the commanded torque of each power source, and determine the final commanded torque of each power source; and A torque monitoring logic unit, configured to: Determine a monitored demand torque, Determine the compensation torque of each power source according to whether the engine clutch is engaged, Determine the commanded torque limit value, and Determine whether there is an abnormality in each torque determination process.

15. The torque monitoring system according to claim 14, wherein, The torque monitoring logic unit is configured to: Receive information from the basic control logic unit, the information including: the commanded torque of each power source based on the driver demand torque; the commanded torque of each power source obtained by adding the intervention torque of each power source to the commanded torque of each power source based on the driver demand torque after reflecting the intervention torque of each power source; the additional torque of each power source for torque compensation, the final torque command of each power source, and the driving mode of the hybrid electric vehicle; and Use the received information to determine the compensation torque and the commanded torque limit value of each power source.

16. The torque monitoring system according to claim 15, wherein: The intervention torque of each power source includes an engine intervention torque and a motor intervention torque; and The torque monitoring logic unit is configured to: Determine the engine intervention torque as the value obtained by subtracting the engine commanded torque based on the driver demand torque from the engine commanded torque after reflecting the intervention torque received from the basic control logic unit; and Determine the motor intervention torque as the value obtained by subtracting the motor commanded torque based on the driver demand torque from the motor commanded torque after reflecting the intervention torque received from the basic control logic unit.

17. The torque monitoring system according to claim 9, wherein, The additional torque of each power source includes an additional engine torque and an additional motor torque.

18. The torque monitoring system according to claim 17, wherein: The additional engine torque is determined as the engine friction torque; and The additional motor torque is determined as the motor torque for compensating for a decrease or increase in the engine output.

19. The torque monitoring system according to claim 9, wherein: The compensation torque of each power source includes an engine compensation torque and a motor compensation torque; and The commanded torque limit value is determined as the sum of the monitored demand torque, the engine compensation torque, and the motor compensation torque.

20. The torque monitoring system according to claim 9, wherein, The control unit is configured to: When the absolute value of the difference between the commanded torque limit value and the sum of the determined final commanded torques of each power source is greater than or equal to a predetermined set value, diagnose that there is the abnormality in each torque determination process; and When the absolute value of the difference between the commanded torque limit value and the sum of the determined final commanded torques of each power source is less than the predetermined set value, diagnose that each torque determination process is normal.

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