JP2012091599A - Hybrid vehicle control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve motor assist gear shift performance with regard to a hybrid vehicle control device.SOLUTION: An integrated controller 20 provides a limit to the MG torque which can be used for rotation speed control of a motor generator MG, with a torque limiting value Tlimit. The torque limiting value Tlimit is set, when a second clutch CL 2 is locked, to a first limit value T1, and when the second clutch CL 2 is in a slip condition, to an addition value of the second limit value T2 and the first limit value T1 which is a correction torque required for rotation change.

Description

  The present invention relates to a control device for a hybrid vehicle.

  2. Description of the Related Art Conventionally, there has been known a hybrid vehicle control device in which an engine, a motor generator, and a transmission are drivingly coupled. In this hybrid vehicle, the engine and the motor generator are connected so as to be able to be intermittently connected by the first clutch, and the motor generator and the output shaft of the transmission are connected so as to be intermittently connected by the second clutch. As a result, the hybrid vehicle disconnects the first clutch, connects the second clutch, and travels using the motor generator as a power source, and connects the first clutch and the second clutch together. The vehicle travels using the engine as a power source, and travels while switching between these modes.

  For example, Patent Document 1 discloses a hybrid vehicle equipped with a control means for controlling the input rotational speed of a transmission to a rotational speed corresponding to a target gear stage at least by a torque of a motor at the time of shifting, that is, a motor assisted shifting. A control device is disclosed. The control means limits the motor torque that can be used for the rotational speed feedback control of the input rotational speed of the transmission based on the target output torque of the transmission and the target change speed of the input rotational speed at the time of shifting. It is configured. As a result, the feeling of popping out of the vehicle due to excessive capacity of the second clutch is suppressed during coast downshifting.

JP 2009-255873 A

  However, when the restriction on the motor torque is set uniformly, there is a possibility that the performance of the motor assist shift cannot be effectively exhibited.

  The present invention has been made in view of such circumstances, and an object thereof is to improve motor-assisted gear shifting performance.

  In order to solve this problem, the present invention provides a control device for a hybrid vehicle having control means for controlling an input rotational speed of a transmission to a rotational speed corresponding to a target gear stage by at least motor torque at the time of shifting. . Here, the control means limits the motor torque that can be used for controlling the rotational speed of the motor by a torque limit value. In this case, the torque limit value is set to the first limit value when the clutch is engaged, and when the clutch is in the slip state, the second limit value and the first limit value, which are correction torques necessary for the rotation change. And the added value.

  According to the present invention, the torque limit value can be variably set by adding the second limit value to the first limit value as necessary. Thereby, since the torque (inner torque) necessary for the rotation change can be taken into consideration, it is possible to appropriately limit the torque of the motor. As a result, the motor-assisted speed change performance can be improved.

Configuration diagram schematically showing drive system of hybrid vehicle Block diagram schematically showing the control system of the hybrid vehicle Functional block diagram of the integrated controller Illustration of target driving force map Explanatory drawing of EV-HEV selection map Explanatory diagram of charge / discharge amount map Timing chart showing torque of motor generator MG A flowchart showing a specific control operation of the integrated controller 20 according to the present embodiment. Flow chart showing the procedure for determining the torque limit value Explanatory drawing showing the transition of torque limit value

  FIG. 1 is a configuration diagram schematically showing a drive system of a hybrid vehicle to which a control device according to the present embodiment is applied. The drive system (powertrain system) of the hybrid vehicle includes an engine E, a first clutch CL1, a motor generator MG, an automatic transmission AT, a second clutch CL2, a propeller shaft PS, a differential DF, Drive shafts DSL, DSR and left and right drive wheels (for example, left and right rear wheels RL, RR) are included.

  The engine E is, for example, a gasoline engine, and the valve opening degree of the throttle valve and the like are controlled based on a control command from an engine controller 21 described later.

  The first clutch CL1 is a clutch disposed between the engine E and the motor generator MG. As the first clutch CL1, for example, a wet multi-plate clutch capable of continuously controlling the oil flow rate and hydraulic pressure with a proportional solenoid can be used. The first clutch CL <b> 1 is controlled to be engaged / released including slip engagement in response to a drive signal (solenoid current command) from the integrated controller 20.

  Motor generator MG is a synchronous motor generator composed of a rotor having a permanent magnet embedded therein and a stator around which a stator coil is wound. This motor generator MG can operate as an electric motor (motor) that is driven to rotate when it is supplied with electric power, or can be generated at both ends of the stator coil when the rotor is rotated by an external force. It can also operate as a generator that generates electrical power. The rotor of motor generator MG is connected to the input shaft of automatic transmission AT via a damper (not shown).

  The second clutch CL2 is a clutch disposed between the motor generator MG and the left and right rear wheels RL, R. As the second clutch CL2, for example, a wet multi-plate clutch capable of continuously controlling the oil flow rate and hydraulic pressure with a proportional solenoid can be used. The second clutch CL <b> 2 is controlled to be engaged / released including slip engagement in response to a drive signal (solenoid current command) from the integrated controller 20.

  The automatic transmission AT is a transmission that automatically switches stepped gear ratios such as forward 5 speed, reverse 1 speed, etc., according to vehicle speed, accelerator opening, and the like. The above-described second clutch CL2 is not newly added as a dedicated clutch, but uses a number of frictional engagement elements among a plurality of frictional engagement elements that are engaged at each gear stage of the automatic transmission AT. It is configured.

  The output shaft of the automatic transmission AT is connected to the left and right rear wheels 8 and 9 via a propeller shaft PS, a differential DF, and left and right drive shafts as a vehicle drive shaft.

  This hybrid vehicle has, for example, two travel modes. The first travel mode is a motor use travel mode (hereinafter referred to as “EV travel mode”) in which the first clutch CL1 is opened and travel is performed using only the power of the motor generator MG as a power source. The second travel mode is an engine use travel mode (hereinafter referred to as “HEV travel mode”) in which the first clutch CL1 is engaged and the engine E is included in the power source.

  FIG. 2 is a block diagram schematically showing a control system of the hybrid vehicle according to the present embodiment. This control system is mainly composed of an integrated controller 20, an engine controller 21, and a motor controller 22, and a hybrid vehicle control device is constituted by these controllers.

  The integrated controller 20 performs integrated control of operating points of the powertrain system. Sensor signals from various sensors are input to the integrated controller 20 in order to perform integrated control. The engine speed sensor 10 detects the speed of the engine E. MG rotation speed sensor 11 detects the rotation speed of motor generator MG. The AT input rotational speed sensor 12 detects the input rotational speed of the automatic transmission AT. The AT output shaft speed sensor 13 detects the output shaft speed of the automatic transmission AT. The SOC sensor 16 detects the state of charge SOC of the battery 9. The APO sensor 17 detects the accelerator opening APO.

  The integrated controller 20 selects an operation mode that can realize the driving force desired by the driver according to the accelerator opening APO, the battery state of charge SOC, and the vehicle speed VSP (proportional to the output shaft rotational speed of the automatic transmission AT). To do. Then, the integrated controller 20 instructs the motor controller 22 to set a target motor generator torque (hereinafter referred to as “target MG torque”) or a target motor generator rotation speed (hereinafter referred to as “target MG rotation speed”), and to the engine controller 21. Command torque. Further, the integrated controller 20 commands a drive signal (solenoid current command) to the solenoid valve 14 that controls the hydraulic pressure of the first clutch CL1 and the solenoid valve 15 that controls the hydraulic pressure of the second clutch CL2.

  The engine controller 21 controls the engine E based on the target engine torque.

  The motor controller 22 controls the motor generator MG based on the target MG torque (or target MG rotation speed). Specifically, the motor controller 22 operates the inverter 3 based on the target MG torque, thereby controlling the motor generator MG through a three-phase alternating current output from the battery 9 via the inverter 3.

  FIG. 3 is a block configuration diagram functionally showing the integrated controller 20. When this integrated controller 20 grasps this functionally, the target driving force calculation unit 100, the mode selection unit 200, the target charge / discharge calculation unit 300, the operating point command unit 400, and the shift control unit 500 Have.

  Hereinafter, a basic control operation of the integrated controller 20 configured by these functional elements will be described. This control operation is called every predetermined period (for example, 10 ms) and executed by the integrated controller 20.

  The target driving force calculation unit 100 calculates a target driving force tFo0 based on the accelerator opening APO and the vehicle speed VSP by referring to, for example, a target driving force map shown in FIG.

The mode selection unit 200 calculates a target mode based on the accelerator opening APO and the vehicle speed VSP by referring to, for example, the EV-HEV selection map shown in FIG.

  The target charge / discharge calculation unit 300 calculates the target charge / discharge power tP from the battery charge state SOC by referring to, for example, the charge / discharge amount map shown in FIG.

  In the operating point command unit 400, based on the accelerator opening APO, the target driving force tFo0, the target mode, the vehicle speed VSP, and the target charging / discharging power tP, as these operating point target values, the transient target engine torque and the target MG The torque, the target second clutch torque capacity (target CL2), the target gear position (target AT) of the automatic transmission AT, and the first clutch solenoid current command (CL1 solenoid current command) are calculated.

  The shift control unit 500 controls the solenoid valve in the automatic transmission AT to achieve these based on the target second clutch torque capacity and the target shift stage of the automatic transmission AT.

  Hereinafter, a specific control operation of the integrated controller 20 according to the present embodiment will be described. FIG. 7 is a timing chart showing the torque of motor generator MG.

  The rotation speed of motor generator MG and the torque of motor generator MG at the time of coast down shift will be described. During a coast down shift, the transmission input rotational speed decreases as the vehicle speed decreases. That is, the rotational speed (MG rotational speed) of the motor generator directly connected to the transmission input shaft is reduced (region (1) in the figure). When the transmission input rotational speed decreases, shifting is started and the transmission input rotational speed is maintained at an idle speed or higher (region (2) in the figure). At this time, in order to advance the downshift in which the transmission input rotational speed is increased, the torque of the motor generator MG (MG torque), which is the transmission input torque, is increased as compared with the running torque before the shift. (Region (3) in the figure). In the region (3), the actual MG torque value subjected to the rotational speed feedback control varies with respect to the target value. In order to increase the input speed of the transmission and advance the speed change, the input speed of the transmission is controlled to the speed corresponding to the target speed, that is, the speed control of the input speed of the transmission, that is, the motor The rotational speed control of the generator MG is used. At this time, a limit (upper limit) is set for the MG torque that is permitted to be used for the rotational speed control of the motor generator MG (value (4) in the figure: torque limit value (torque upper limit value)). It becomes.

  FIG. 8 is a flowchart showing a specific control operation of the integrated controller 20 according to the present embodiment. The process shown in this flowchart shows the flow of control when limiting the MG torque, is called at a predetermined cycle, and is executed by the integrated controller 20.

  In step 1 (S1), the integrated controller 20 determines whether or not there is a shift request. If an affirmative determination is made in step 1, that is, if there is a shift request, the process proceeds to step 2 (S2). On the other hand, if a negative determination is made in step 1, that is, if there is no shift request, this routine is exited. In this case, in order to achieve the target driving force tFo0 of the vehicle, the motor generator MG continues to run under torque control.

  In step 2, the integrated controller 20 determines whether or not an actual shift has been started in the automatic transmission AT in response to the shift request. When a negative determination is made in step 2, that is, before the actual shift is started, the process proceeds to step 3 (S3). On the other hand, if an affirmative determination is made in step 2, that is, if an actual shift is started, the routine proceeds to step 4 (S4).

In step 3, the integrated controller 20 continues the torque control similar to that before the shift. This is because the shift clutch has not started to slip until the actual shift is started.

  In step 4, the integrated controller 20 starts the rotational speed control of the motor generator MG. In this case, the integrated controller 20 advances the shift while maintaining the deceleration torque by the clutch torque.

  In step 5 (S5), the integrated controller 20 determines the automatic transmission AT based on the target output torque of the automatic transmission AT and the target rotational speed change speed of the input rotational speed of the automatic transmission AT, that is, the MG rotational speed. Calculate the target input torque. Here, the target output torque of the automatic transmission AT is the sum of the coast torque of the vehicle and the cooperative regenerative torque with the brake.

  In step 6 (S6), integrated controller 20 determines a limit value (torque limit value) for limiting the MG torque that is permitted to be used for the rotational speed control of motor generator MG. Here, FIG. 9 is a flowchart showing a procedure for determining the torque limit value.

  First, in step 10 (S10), the integrated controller 20 determines whether or not the current gear position of the automatic transmission AT is a low speed gear. Here, the low speed stage refers to a low speed side gear stage including at least the first speed (the first gear stage having the largest gear ratio), and is appropriately determined according to the specifications of the automatic transmission AT. If an affirmative determination is made in step 10, that is, if the shift speed is a low speed, the process proceeds to step 11 (S11). On the other hand, if a negative determination is made in step 11, that is, if the shift speed is not a low speed, the process proceeds to step 12 (S12).

  In step 11, the integrated controller 20 sets a first limit value T1 that functions as part of the torque limit value. Specifically, the first limit value T1 is set as a value obtained by adding a predetermined value α to the target input torque. Here, the predetermined value α is a margin that is allowable as a change in vehicle behavior, that is, a driving force, and is determined according to each shift stage included in the low speed stage.

  In step 12, the integrated controller 20 sets a first limit value T1. Specifically, the first limit value T1 is determined as zero from the viewpoint that the MG torque is not limited by the first limit value T1.

  In step 13 (S13), the integrated controller 20 determines whether or not the second clutch CL2 is in a slip state. The slip amount of the second clutch is obtained by subtracting the integrated value of the output rotation and the gear ratio from the input rotation of the second clutch CL2. Therefore, based on the slip amount of the second clutch, it can be determined whether or not the second clutch CL2 is in the slip state. In step 13, in order to determine the slip state in a superimposed manner through different state quantities, the determination is made depending on whether or not each of the following two upper limits is provided.

The first method is determined to be in a slip state by providing the following equation.
(Formula 1)
MG rotation speed-(wheel speed x final gear ratio x shift speed) ≥ determination threshold In this formula, the integrated value of the wheel speed and the gear ratio of the automatic transmission AT to the final gear and the current shift speed is calculated from the MG rotation speed. The slip state is determined on the condition that the subtracted value is equal to or greater than the determination threshold value.

The second method is determined to be in the slip state by providing the following equation.
(Formula 2)
Input rotation speed of automatic transmission AT− (propeller shaft rotation speed × shift speed) ≧ judgment threshold In the above formula, the integrated value of propeller shaft PS and the current shift speed is subtracted from the input rotation speed of automatic transmission AT. The slip state is determined on condition that the value is equal to or greater than the determination threshold.

  If an affirmative determination is made in step 13, that is, if the second clutch CL2 is in the slip state, the process proceeds to step 14 (S14). On the other hand, if a negative determination is made in step 13, that is, if the second clutch CL2 is not in the slip state, the process proceeds to step 18 (S18) described later.

  In step 14, the integrated controller 20 determines whether or not the first clutch CL1 is engaged. The state of the first clutch CL1 can be determined from the detection result when a stroke sensor is provided in the first clutch CL1, and through a drive signal to the solenoid valve 14 that controls the hydraulic pressure of the first clutch CL1. Judgment can be made.

  If an affirmative determination is made in step 14, that is, if the first clutch CL1 is engaged, the process proceeds to step 15 (S15). On the other hand, if a negative determination is made in step 14, that is, if the first clutch CL1 is not engaged, the process proceeds to step 16 (S16).

  In step 15, the integrated controller 20 calculates an inertia torque J, which is a correction torque necessary for the rotation change, on condition that the first clutch CL1 is engaged. Specifically, the inertia torque J is calculated as an added value of the inertia torque Je of the engine E and the inertia torque Jm of the motor generator MG.

  In step 16, the integrated controller 20 calculates the inertia torque J on the condition that the first clutch CL1 is not engaged. Specifically, the inertia torque J is calculated as the inertia torque Jm of the motor generator MG.

  In step 17 (S17), the integrated controller 20 sets a second limit value T2 that functions as a part of the MG torque upper limit value. Specifically, the second limit value T2 is calculated as an integrated value of the inertia torque J and the target input rotational speed of the automatic transmission AT, that is, the differential value Win_dot of the target MG rotational speed.

  In step 18, the integrated controller 20 sets a second limit value T2. In step 12, the second limit value T2 is determined to be zero so that the MG torque is not limited as the second limit value T2.

In step 19 (S19), the integrated controller 20 calculates a torque limit value Tlimit. This torque limit value Tlimit indicates the upper limit value of the MG torque that is permitted to be used for the rotational speed control of motor generator MG. Specifically, the torque limit value Tlimit is the first limit value T
It is calculated as an added value of 1 and the second limit value T2.

As described above, in the present embodiment, the integrated controller 20 functions as a control unit that controls the input rotational speed of the automatic transmission AT to the rotational speed corresponding to the target shift stage by at least the MG torque when the automatic transmission AT shifts. . In this case, the integrated controller 20 limits the MG torque that can be used for the rotational speed control of the motor generator MG by the torque limit value Tlimit. Here, the torque limit value Tlimit is set to the first limit value T1 when the second clutch CL2 is engaged, and when the second clutch CL2 is in the slip state, the torque limit value Tlimit is a correction torque that is necessary for a change in rotation. 2 is set to an added value of the limit value T2 and the first limit value T1.

According to such a configuration, as shown in FIG. 10, the torque limit value Tlimit can be variably set by adding the second limit value T2 to the first limit value T1 as necessary. Thereby, since the torque (inert torque) necessary for the rotation change can be taken into consideration, it is possible to appropriately limit the MG torque, and it is possible to improve the motor assist speed change performance. As a result, it is possible to achieve both suppression of the feeling of jumping out of the vehicle and improvement of the speed change performance.

In the present embodiment, the integrated controller 20 sets the limit based on the first limit value T1 included in the torque limit value Tlimit as the target input torque of the automatic transmission AT when the shift stage of the automatic transmission AT is a low speed stage. On the other hand, when the shift stage of the automatic transmission AT is not a low speed stage, the limit by the first limit value T1 included in the torque limit value Tlimit is not performed.

  According to such a configuration, the MG torque is limited only to the low speed stage having a great influence on the vehicle behavior, and the unnecessary speed stage is not limited. Thereby, it is possible to further suppress the influence on the motor assist speed change performance due to the limitation of the MG torque.

  Further, in the present embodiment, the integrated controller 20 sets the first limit value T1 to the target input torque of the automatic transmission AT and the margin α that can be allowed as a change in driving force (for each of the shift stages included in the low speed stage). Is set as an addition value).

  According to such a configuration, the first limit value T1 can be set according to the gear position, so that the MG torque can be limited with high accuracy, and the situation in which the feeling during shifting is impaired is suppressed. can do.

  In the present embodiment, the integrated controller 20 determines that the second clutch CL2 is in the slip state when the slip state is determined in a superimposed manner through different state quantities.

As described above, when the second clutch CL2 is in the slip state, the second limit value T2 is added as the torque limit value Tlimit. Therefore, if this is not performed when the second clutch CL2 is reliably slipping, the vehicle behavior will not be affected. Therefore, in this embodiment, since the slip state is determined in a superimposed manner through different state quantities, it can be accurately determined whether or not the second clutch CL2 is in the slip state.

  In the present embodiment, when the first clutch CL1 is in the engaged state, the integrated controller 20 considers the engine inertia and the motor inertia in setting the correction torque (inert torque) that is the second limit value T2. When the first clutch CL1 is in a state other than the engaged state, the motor inertia is considered in setting the correction torque (inert torque) that is the second limit value T2.

  According to such a configuration, the inertia torque as the second limit value T2 can be set with high accuracy.

  Further, in the present embodiment, as shown in FIG. 10, the integrated controller 20 executes the restriction by the second restriction value T2 during the period in which the actual transmission is being performed in the transmission (determination in step 2 of FIG. 8). Process, determination process of step 13 in FIG. 9).

  According to such a configuration, the restriction by the second restriction value T2 is performed in the inertia phase where the input rotation of the automatic transmission AT changes. Thereby, since the scene which adds the 2nd limit value T2 can be limited, the influence on a vehicle behavior can be decreased.

  Although the hybrid vehicle control device according to the embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the invention. Nor. For example, the configuration of the hybrid vehicle is not limited to the above configuration, and a new clutch may be provided on either the input shaft or the output shaft of the transmission as the second clutch CL2.

DESCRIPTION OF SYMBOLS 10 Engine rotational speed sensor 11 MG rotational speed sensor 12 AT input rotational speed sensor 13 AT output shaft rotational speed sensor 14 Solenoid valve 15 Solenoid valve 16 SOC sensor 17 APO sensor 20 Integrated controller 21 Engine controller 22 Motor controller 100 Target driving force calculating part 200 mode selection unit 300 target charge / discharge calculation unit 400 operating point command unit 500 shift control unit E engine MG motor generator AT automatic transmission CL1 first clutch CL2 second clutch

Claims (6)

In a hybrid vehicle control device comprising: a motor; a transmission disposed between the motor and drive wheels; and a clutch disposed between the motor and drive wheels.
Control means for controlling the input rotational speed of the transmission to a rotational speed corresponding to the target shift stage at least by the torque of the motor at the time of shifting;
The control means limits the motor torque that can be used for the rotation speed control of the motor by a torque limit value,
The torque limit value is set to a first limit value when the clutch is engaged, and when the clutch is in a slip state, the second limit value and the first limit are correction torques necessary for a change in rotation. A control device for a hybrid vehicle, characterized in that it is set to a value added to the value.   The control means performs restriction by a first limit value included in the torque limit value according to a target input torque of the transmission, when the shift speed of the transmission is a low speed including at least the first speed, 2. The control device for a hybrid vehicle according to claim 1, wherein when the shift stage of the transmission is not the low speed stage, the restriction by the first limit value included in the torque limit value is not performed.   The control means adds the first limit value to a target input torque of the transmission and a margin that is set according to each of the shift stages included in the low speed stage and is allowed as a change in driving force. The hybrid vehicle control device according to claim 2, wherein the control device is set as follows.   4. The hybrid according to claim 1, wherein the control unit determines that the clutch is in a slip state when a slip state is determined in a superimposed manner through different state quantities. 5. Vehicle control device. The hybrid vehicle further includes an engine, and a clutch disposed between the engine and the motor,
When the clutch between the engine and the motor is in an engaged state, the control means considers the engine inertia and the motor inertia in setting the correction torque that is the second limit value, and the clutch between the engine and the motor 5. The hybrid vehicle control device according to claim 1, wherein a motor inertia is considered in setting of the correction torque that is the second limit value when is in a state other than engagement. 6. .   6. The control apparatus for a hybrid vehicle according to claim 1, wherein the control means executes the restriction based on the second restriction value during a period during which an actual speed change is performed in the transmission. .

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