JP2024022818A - Control device of hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device of a hybrid vehicle that can improve accuracy in determining a failure of a torsional damper.

SOLUTION: A control device of a hybrid vehicle, which comprises a torsional damper provided between an engine and a motor, obtains damper characteristics showing a relation between input torque and a torsion angle in the torsional damper, by inputting torque to the torsional damper while varying output torque of the motor and by detecting the torsion angles of the torsional damper (a step S1), calculates hysteresis torque which is a difference between input torque which becomes a predetermined torsion angle in a course of increasing torque inputted to the torsional damper in the damper characteristics and input torque which becomes a predetermined torsion angle in a course of decreasing the torque inputted to the torsional damper (a step S2), and when the calculated hysteresis torque is larger than a predetermined specific value, determines a failure of the torsional damper (a step S4).

SELECTED DRAWING: Figure 4

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention relates to a control device for a hybrid vehicle that includes a torsional damper between an engine and a motor as a driving force source, and particularly to a control device that detects failure of the torsional damper.

Patent Document 1 describes a device that determines a failure of a torsional damper provided on an output shaft of an engine. This failure determination device detects the torsional angle of the torsional damper by outputting torque from the motor installed on the output side of the torsional damper when the engine is stopped, and The actual value of the angle is compared with the estimated value of the torsion angle according to the output torque of the motor to determine a failure of the torsional damper.

Note that Patent Document 2 describes a control device configured to appropriately perform control based on the characteristics of a damper mechanism. This control device learns the characteristics such as the torsional rigidity, hysteresis torque, and backlash dimension of the damper mechanism from the input torque and torsion angle to the damper mechanism, and performs predetermined control based on the learned characteristics. It is configured.

JP2009-244251A Japanese Patent Application Publication No. 2018-79849

The torsion damper failure determination device described in Patent Document 1 is configured to determine failure of the torsion damper from input torque and torsion angle at the time of measurement. However, the characteristics of a torsional damper are determined by torsional rigidity, hysteresis torque, backlash size, etc., and it is difficult to evaluate the damper by simply comparing the measured value and estimated value of the torsion angle when a predetermined input torque is input. It may not be possible to grasp changes in the characteristics of the mechanism. Specifically, the torsional damper failure determination device described in Patent Document 1 inputs a predetermined torque to the torsional damper and compares the actual measured value and estimated value of the torsion angle at that time. , hysteresis, which is the difference between the magnitude of the input torque that results in a predetermined torsion angle when the torque input to the torsional damper is increasing, and the magnitude of the input torque that results in a predetermined torsion angle when the input torque is decreased. Torque cannot be determined, and changes in hysteresis torque due to age-related deterioration of the torsional damper may not be ascertained.

The present invention has been made with attention to the above-mentioned technical problem, and an object of the present invention is to provide a control device for a hybrid vehicle that can improve the accuracy of determining failure of a torsional damper. .

In order to achieve the above object, the present invention provides a control device for a hybrid vehicle, comprising an engine and a motor as a driving force source, and a torsional damper provided between the engine and the motor. , by inputting torque to the torsional damper while changing the output torque of the motor and detecting the torsional angle of the torsional damper, the relationship between the input torque in the torsional damper and the torsional angle is shown. obtaining damper characteristics, and decreasing the input torque that results in a predetermined torsion angle and the torque input to the torsional damper in the process of increasing the torque input to the torsional damper in the damper characteristics. A hysteresis torque, which is the difference between the input torque and the input torque that results in the predetermined torsion angle during the process of It is characterized by determining that.

According to the present invention, dynamic damper characteristics of the torsional damper can be obtained by inputting torque to the torsional damper while changing the output torque of the motor and detecting the torsion angle of the torsional damper. can. By acquiring the dynamic damper characteristics in this way, the hysteresis torque of the torsional damper can be calculated. When a torsional damper deteriorates over time, it is assumed that hysteresis torque increases. Therefore, by determining that the torsional damper has failed when the hysteresis torque is larger than a predetermined value, it is possible to improve the accuracy of determining the failure of the torsional damper.

It is a schematic diagram for explaining the function of the torsional damper in the embodiment of the present invention. FIG. 3 is a diagram showing damper characteristics of a torsional damper. FIG. 6 is a diagram showing an example of damper characteristics when a torsional damper deteriorates over time. It is a flow chart for explaining an example of control performed by a control device in an embodiment of the present invention. It is a flow chart for explaining a subroutine for measuring damper characteristics.

The present invention will be described based on embodiments shown in the drawings. Note that the embodiments described below are merely examples of embodying the present invention, and are not intended to limit the present invention.

FIG. 1 shows a schematic diagram for explaining the function of a torsional damper in an embodiment of the present invention. The torsional damper 1 shown in FIG. 1 includes an input element 2, an output element 3 provided to be rotatable relative to the input element 2, and an elastic member (coil spring) provided between the input element 2 and the output element 3. 4 and a friction mechanism 5 interposed between the input element 2 and the output element 3, and is configured to attenuate the pulsation of torque output from the engine 6.

The input element 2 is a rotating member connected to the output shaft (crankshaft) 7 of the engine 6, and can be configured by, for example, a conventionally known flywheel.

The engine 6 is configured similarly to an engine provided in a conventional vehicle, and is configured to generate power by burning a mixture of air and fuel such as gasoline or diesel. Therefore, as the air-fuel mixture is combusted, torque pulsations occur in accordance with the combustion cycle. In addition, a crank angle sensor 8 is provided to detect the rotation angle (rotation speed) of the engine 6, and a brake mechanism (more specifically, , a meshing type brake mechanism) 9 is provided.

The output element 3 is connected to an output member such as a drive wheel (not shown) so that torque can be transmitted, and is further connected to a motor (MG) 10 so that torque can be transmitted. Specifically, for example, similar to the hybrid vehicle described in Patent Document 2 mentioned above, the output shaft 11 of the torsional damper 1, the output shaft 12 of the motor 10, and the rotating member connected to the drive wheels are connected to each other. It is connected to a differential mechanism (not shown). Note that the output shaft 11 of the torsional damper 1 is provided passing through the motor 10, and the rotor of the motor 10 is connected to the output shaft 11 so as to be able to rotate together with the output shaft 11, and a speed change mechanism (not shown) is connected to the tip of the output shaft 11. It may also be configured by

The motor 10 can be configured with a permanent magnet type synchronous motor, an induction motor, etc., similar to the motor provided as a driving force source of a conventional hybrid vehicle, and a motor for detecting its rotation angle (rotation speed). A resolver 13 is provided.

The input element 2 and the output element 3 described above are configured, for example, so that a part thereof faces each other in the rotational direction, and a coil spring 4 is provided in the opposed part. Therefore, when the input element 2 and the output element 3 rotate relative to each other, the coil spring 4 is compressed, and an elastic force is generated in a direction that reduces the rotation angle (phase angle).

FIG. 2 shows the damper characteristics of the torsional damper 1 configured as described above. As shown in FIG. 2, the torsional damper 1 has a small torsion angle (absolute value) Φ, which is the difference in rotation angle (phase) between the input element 2 and the output element 3, similar to conventionally known torsional dampers. In this region, the amount of increase in input torque required to increase the torsional angle (hereinafter referred to as torsional rigidity) is relatively small. Hereinafter, this region will be referred to as a low torque region. Furthermore, in a predetermined range where the torsion angle (absolute value) is larger than in the low torque range, the torsional rigidity is larger than in the low torque range. Hereinafter, this region will be referred to as a medium torque region. Furthermore, in a region where the torsion angle (absolute value) is larger than in the medium torque region, the torsional rigidity is larger than in the medium torque region. Hereinafter, this region will be referred to as a high torque region.

The torsion angle that forms the boundary between the medium torque range and the high torque range described above is the torsion angle at which the strands come into close contact with each other in the central axis direction of the coil spring 4. Therefore, when the output torque of the engine 6 during normal driving is input to the torsional damper 1, the torsion angle is configured to be less than the torsion angle that is the boundary between the medium torque range and the high torque range. ing. In the following description, the twist angle at which the wires come into close contact with each other will be referred to as the maximum allowable twist angle. In addition, in the low torque range and medium torque range, similar to conventional torsional dampers, the magnitude of the torque is such that a predetermined torsion angle occurs when the input torque increases, and the predetermined torsion angle becomes a predetermined torsion angle when the input torque decreases. It has a hysteresis torque which is the difference between the magnitude of the torque and the torque. Note that the torsion angle can be determined, for example, based on the detection values of the crank angle sensor 8 that detects the rotation angle of the engine 6 and the resolver 13 that detects the rotation angle of the motor 10.

The torsional damper 1 configured as described above attenuates torque pulsations input from the engine 6 by relative rotation of the input element 2 and output element 3, that is, by compression of the coil spring 4. It is configured as follows. Specifically, for example, when the engine torque pulsates when the torsion angle is ΦA in FIG. 2, the engine torque increases, and as shown by arrow a in FIG. 2, the engine torque increases. As the torsion angle increases along the upper line and in this state the engine torque decreases, the torsion angle decreases along the lower line as shown by arrow b in Figure 2 from the increased torsion angle. . That is, the magnitude of the hysteresis torque H (for example, H1) is set to be smaller than the total amplitude of the engine torque (that is, the difference between the minimum value and the maximum value of the engine torque) Tmax.

The magnitude of this hysteresis torque H changes mainly depending on the frictional force of the friction mechanism 5. Therefore, when the torsional damper 1 deteriorates over time and the friction coefficient of the friction mechanism 5 increases, the hysteresis torque H increases as shown in FIG. 3. Therefore, when the magnitude of the hysteresis torque H exceeds the magnitude of the total amplitude of the engine torque Tmax, the torsion angle of the torsional damper 1 does not change, making it impossible to obtain the vibration damping effect of the torsional damper 1.

Therefore, the hybrid vehicle control device according to the embodiment of the present invention calculates the hysteresis torque H, and determines that the torsional damper 1 has failed when the hysteresis torque H is larger than a predetermined value Hlim. It is configured as follows. FIG. 4 shows a flowchart for explaining an example of the control. In the control example shown in FIG. 4, damper characteristics are first measured (step S1). Specifically, by executing the subroutine shown in FIG. 5, torque is input from the motor 10 to the torsional damper 1, and the torsion angle at that time is detected.

FIG. 5 shows an example of a subroutine for measuring damper characteristics. In the example shown in FIG. 5, it is first determined whether the vehicle is stopped, that is, whether the vehicle speed is "0" (step S11). ). This step S11 can be determined based on a signal detected by a vehicle speed sensor.

If the determination in step S11 is affirmative because the vehicle is stopped, it is determined whether the shift range is in the "P" range (step S12). This step S12 can be determined based on detecting the operating position of the shift lever, or detecting the position of the parking pole.

If the shift range is in the "P" range and the result in step S12 is affirmative, it is determined whether the engine speed is "0" (step S13). This step S13 can be determined based on the detected value of the crank angle sensor 8.

Further, if the engine rotation speed is "0" and the determination in step S13 is affirmative, it is determined whether or not it is necessary to operate the engine 6 (step S14). This step S14 is determined based on, for example, whether there is a request to charge the power storage device that supplies electric power to the motor 10, or whether there is a request to warm up the engine 6 or the catalyst that purifies the exhaust gas of the engine 6. can do.

If the judgment in step S14 is negative because there is no need to operate the engine 6, torque is input from the motor 10 to the torsional damper 1, and the torsion angle when the torque is input is started to be measured (step S15). That is, in steps S11 to S14, it is determined whether the conditions for measuring the twist angle are met. Therefore, because the vehicle speed is not "0", the shift range is not in the "P" range, or the engine speed is not "0", a negative determination is made in any of steps S11 to S13. If the result in step S14 is affirmative because the engine 6 needs to be operated, it is determined that the conditions for measuring the twist angle are not satisfied, and the process returns to step S11.

Here, the method of measuring the twist angle in step S15 will be explained. In the example shown here, first, the rotation of the output shaft 7 of the engine 6 is stopped (prohibited) by the brake mechanism 9. In this state, the torque of the motor 10 is continuously increased and the twist angles are sequentially measured. Similarly, while continuously decreasing the torque of the motor 10, the twist angles are sequentially measured. The direction of the torque of this motor 10 is executed in both positive and negative directions. By measuring the torsion angle while changing the torque input to the torsional damper 1 in this way, the damper characteristics can be measured.

In the process of measuring the twist angle as described above, it is determined whether the conditions for measuring the twist angle are not satisfied (step S16). Specifically, it is determined whether the shift range is in a range other than the "P" range, whether the vehicle speed is other than "0", and whether or not it is necessary to operate the engine.

If the condition for measuring the torsion angle is not satisfied and the determination in step S16 is affirmative, the measurement is interrupted (step S17) and the process returns. On the other hand, if the condition for measuring the torsion angle is satisfied and the result is negative in step S16, it is determined whether or not the measurement has ended (step S18), and the measurement is ended. If so, exit this routine. On the other hand, if the measurement has not been completed, the process returns.

After measuring the damper characteristics as described above, the hysteresis torque H is calculated (step S2). This step S2 extracts a predetermined torsion angle in a range less than the maximum allowable torsion angle, and in the process of increasing the input torque, determines the magnitude of the input torque that results in a predetermined torsion angle, and the process of decreasing the input torque. What is necessary is to find the difference between the input torque and the magnitude of the input torque that results in a predetermined twist angle. In that case, the hysteresis torque H1 when the torsion angle is on the positive side, that is, the rotation angle of the input element 2 is larger than the rotation angle of the output element 3, and the hysteresis torque H1 when the torsion angle is on the negative side, that is, the rotation angle of the output element 3 is Among the hysteresis torques H2 that are larger than the rotation angle of the input element 2, the larger hysteresis torque is adopted.

Subsequently, it is determined whether the hysteresis torque H (H1 or H2) calculated in step S2 is larger than a predetermined value Hlim (step S3). This predetermined value Hlim is set to be less than or equal to the maximum value Tmax of the total amplitude of the engine torque. That is, even if the hysteresis torque H increases due to aging of the torsional damper 1, the predetermined value Hlim is determined so that vibrations can be damped when the engine torque pulsates.

If the hysteresis torque H is less than or equal to the predetermined value Hlim and a negative determination is made in step S3, the process returns to step S1. In other words, it is determined that the torsional damper 1 has not deteriorated over time to the extent that it has failed. On the other hand, if the hysteresis torque H is larger than the predetermined value Hlim and the determination in step S3 is affirmative, the torsional damper 1 is not able to exhibit the vibration damping effect required of the torsional damper 1. It is judged to be a failure because it has deteriorated over time. Therefore, the driver is notified of the failure of the torsional damper 1 (step S4), and this routine is temporarily terminated.

As described above, by inputting torque to the torsional damper 1 while continuously changing the output torque of the motor 10 and sequentially detecting the torsion angle of the torsional damper 1, the dynamic damper characteristics can be obtained. By acquiring such dynamic damper characteristics, the hysteresis torque H of the torsional damper 1 can be calculated. When the torsional damper 1 deteriorates over time, it is assumed that the hysteresis torque H increases. Therefore, by determining that the torsional damper 1 has failed when the hysteresis torque H is larger than the predetermined value Hlim, it is possible to improve the accuracy of determining the failure of the torsional damper 1.

1 Torsion damper 2 Input element 3 Output element 4 Coil spring 5 Friction mechanism 6 Engine 8 Crank angle sensor 9 Brake mechanism 10 Motor 13 Resolver

Claims (1)

A control device for a hybrid vehicle, comprising an engine and a motor as a driving force source, and a torsional damper provided between the engine and the motor,
By inputting torque to the torsional damper while changing the output torque of the motor and detecting the torsional angle of the torsional damper, the relationship between the input torque in the torsional damper and the torsional angle was shown. Obtain the damper characteristics,
In the damper characteristics, the input torque that results in a predetermined torsion angle in the process of increasing the torque input to the torsional damper, and the predetermined torque in the process of decreasing the torque input to the torsional damper. Calculate the hysteresis torque, which is the difference between the input torque and the torsion angle of
A control device for a hybrid vehicle, wherein when the calculated hysteresis torque is larger than a predetermined value, it is determined that the torsional damper has failed.

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