JP2024085162A - Control device - Google Patents

Abstract

To provide a control device capable of reducing a shock when a vehicle shifts from driven travelling to drive travelling.SOLUTION: A control device of a vehicle includes a continuously variable transmission on a drive power source side on a power transmission path between a drive power source and driving wheels, and a gear mechanism on a driving wheel side on the power transmission path. The control device includes: a control part which, when shifting a travelling state of the vehicle from driven travelling in which power is transmitted from the gear mechanism side to the drive power source side to drive travelling in which the power is transmitted from the drive power source side to the gear mechanism side, executes rattling control with respect to the gear mechanism by changing an output torque of the drive power source from negative to positive; and a calculation part for calculating loss by an inertia torque inputted in the continuously variable transmission, from the time change of each rotational frequency of an output shaft of the drive power source and an input shaft of the continuously variable transmission. The control part corrects the output torque in the rattling control according to the loss.SELECTED DRAWING: Figure 2

Description

The present invention relates to a control device.

When the vehicle transitions from driven to engine-driven driving in response to accelerator pedal depression, backlash reduction control is performed to suppress the increase in output torque in order to suppress the rattle shock caused by the increase in engine output torque (see, for example, Patent Document 1).

JP 2009-047080 A

In the case of vehicles equipped with continuously variable transmissions, a loss of inertia torque occurs due to an increase in engine speed during acceleration. This reduces the torque of the drive shaft, and the timing of the backlash elimination control is delayed, which may result in the rattle shock not being suppressed.

Therefore, the present invention was made in consideration of the above problems, and aims to provide a control device that can reduce the shock when the vehicle changes from driven driving to driving driving.

The control device of the present invention is a control device for a vehicle equipped with a continuously variable transmission on the driving force source side of a power transmission path between a driving force source and a driving wheel, and equipped with a gear mechanism on the driving wheel side of the power transmission path. When the running state of the vehicle is shifted from a driven running state in which power is transmitted from the gear mechanism side to the driving force source side to a driving running state in which power is transmitted from the driving force source side to the gear mechanism side, the control device has a control unit that changes the output torque of the driving force source from negative to positive to execute backlash elimination control for the gear mechanism, and a calculation unit that calculates loss due to inertia torque input to the continuously variable transmission from the time change in the rotation speed of the output shaft of the driving force source and the input shaft of the continuously variable transmission, and the control unit corrects the output torque in the backlash elimination control according to the loss.

The present invention can reduce shocks that occur from the gear mechanism when the vehicle accelerates.

FIG. 1 is a configuration diagram showing an example of a vehicle system. FIG. 2 is a time chart showing an example of backlash elimination control. FIG. 3 is a flowchart showing an example of processing by an ECU (Electronic Control Unit).

Figure 1 is a configuration diagram showing an example of a system of a vehicle 9. The vehicle 9 is, for example, a hybrid vehicle, and has an ECU 1, an engine (ENG) 2, a damper 3, a differential mechanism 4, motor generators (MG) 51, 52, a continuously variable transmission (A/T) 61, a differential gear 62, a battery 54, an inverter 53, a drive shaft 60, and a pair of drive wheels 63. The vehicle 9 also has an accelerator opening sensor 90, a crank angle sensor 91, resolvers 92, 93, and a rotation speed sensor 94.

The engine 2 and MGs 51 and 52 are an example of a driving force source for the vehicle 9. In this example, a gasoline engine is used as the engine 2, but this is not limited thereto, and a diesel engine may also be used.

MGs 51 and 52 have a stator and a rotor, and output shafts 50 and 55 are integrally provided at the center of each rotor. An inverter 53 is electrically connected to MGs 51 and 52. The inverter 53 is connected to a battery 54 such as a lithium-ion battery. Resolvers 92 and 93 detect the rotation angles of the output shafts 50 and 55, respectively, and output the detected rotation angles to the ECU 1. MGs 51 and 52 can operate as either a motor or a generator.

The crank angle sensor 91 detects the angle of the crankshaft 20 of the engine 2 and outputs it to the ECU 1. The torque of the engine 2 is input from the crankshaft 20 to the damper 3. The output shaft of the damper 3 is connected to the input shaft 40 of the differential mechanism 4.

The differential mechanism 4 is a single-pinion type planetary gear mechanism, and includes an input shaft 40, an output gear 41, a sun gear S, a ring gear R, and a carrier CA. The sun gear S is connected to the output shaft 50 of the MG51, the carrier CA is connected to the input shaft 40, and the ring gear R is connected to the output gear 41. The output gear 41 transmits torque to the continuously variable transmission 61.

The output torque of the MG51 is added to the output torque of the engine 2 via the differential mechanism 4. At this time, the output torque of the MG51 is amplified according to the planetary gear ratio of the number of teeth of the sun gear S to the number of teeth of the ring gear R. In addition, the output gear 56 provided on the output shaft 55 of the MG52 is connected to the output gear 41 of the differential mechanism 4 via a gear mechanism (not shown). In this way, the output torque of the MG52 is added to the output torque of the engine 2. The output torque is input from the differential mechanism 4 to the input shaft 65 of the continuously variable transmission 61.

The continuously variable transmission 61 transmits the driving force of the engine 2 and MGs 51, 52 to the driving wheels 63. The continuously variable transmission 61 changes the rotation of the input shaft 65 and outputs it from the output shaft 66 by continuously switching the gear ratio on the time axis, for example, by means of a pulley or the like. The gear ratio of the continuously variable transmission 61 is dynamically controlled by the ECU 1 according to the vehicle speed and the opening degree of an accelerator pedal (not shown). The rotation speed sensor 94 detects the rotation speed of the input shaft per unit time and outputs it to the ECU 1. The output shaft 66 is connected to the differential gear 62, and the output torque is output from the continuously variable transmission 61 to the differential gear 62.

The differential gear 62 is an example of a gear mechanism. The differential gear 62 is connected to the drive shaft 60 of the drive wheels 63. The differential gear 62 transmits the driving force of the continuously variable transmission 61 to the drive shaft 60 and the drive wheels 63 so that a difference in the rotation speed of each drive wheel 63 occurs.

In this way, in the power transmission path between the engine 2 and MGs 51 and 52 and the drive wheels 63, the continuously variable transmission 61 is provided on the engine 2 and MGs 51 and 52 side, and the differential gear 62 is provided on the drive wheels 63 side. In addition, the accelerator pedal position sensor 90 detects the accelerator pedal position and outputs the detected position to the ECU 1.

The ECU 1 is an example of a control device. The ECU 1 controls the output torque of the engine 2 and the MGs 51 and 52 in response to the detection value of the accelerator opening sensor 90, and controls the running state of the vehicle 9. The ECU 1 has a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory), all of which are not shown.

The ECU 1 has, for example, a torque control unit 10, an inertia torque calculation unit 11, and a data storage unit 12 as software functions that drive the CPU. Note that the torque control unit 10, the inertia torque calculation unit 11, and the data storage unit 12 may be realized by hardware such as an integrated circuit (IC).

The torque control unit 10 controls the total output torque output to the drive shaft 60 by controlling the output torque of each of the engine 2 and MGs 51 and 52. The torque control unit 10 determines the target torque from map data in the data storage unit 12 based on the detection value of the accelerator opening sensor 90, for example. The torque control unit 10 controls the output torque of the engine 2 by adjusting the ignition timing and fuel injection amount of the engine 2, for example, and controls the output torque of the MGs 51 and 52 by PWM controlling the inverter 53. Note that in this example, an example of controlling the output torque of each of the engine 2 and MGs 51 and 52 is given, but this is not limited thereto, and for example, only the output torque of the MG 51 may be controlled.

The torque control unit 10 transitions the driving state of the vehicle 9 from driven driving to driving in response to the accelerator being turned on. When the vehicle 9 is driven, the power is transmitted from the differential gear 62 side to the engine 2 and MGs 51 and 52 side, and when the vehicle is driven, the power is transmitted from the engine 2 and MGs 51 and 52 side to the differential gear 62 side. When transitioning the driving state of the vehicle 9 from driven to driving, the torque control unit 10 changes the output torque of the engine 2 from negative to positive, and executes backlash elimination control for the backlash of the gear mechanism.

The torque control unit 10 calculates the target torque based on the detection value of the accelerator opening sensor 90, and sets the execution time of the backlash elimination control according to the target torque and the rotation speed of the drive shaft 60. At this time, the torque control unit 10 uses the rotation speed Ne of the crankshaft 20 obtained from the detection value of the crank angle sensor 91, the rotation speeds Nm1 and Nm2 per unit time of the output shafts 50 and 55 obtained from the detection values of the resolvers 92 and 93, respectively, the gear ratio of the continuously variable transmission 61, and the planetary gear ratio of the differential mechanism 4 to calculate the execution time. Note that the torque control unit 10 is an example of a control unit.

The torque control unit 10 corrects the output torque according to the inertia torque loss during backlash elimination control so that the delay in the timing of backlash elimination caused by the loss of inertia torque (hereinafter referred to as inertia torque loss) corresponding to the increase in the rotation speeds Ne, Nm1, and Nm2 during acceleration is suppressed.

Tine = Ine (dNe/dt) + Inin (dNnin/dt)
+ Inm1 (dNm1/dt) + Inm2 (dNm2/dt) ... (1)

The inertia torque calculation unit 11 calculates the inertia torque loss Tine, for example, using the above formula (1). Here, Tine is the inertia of the crankshaft 20, Inin is the inertia of the input shaft 65 of the continuously variable transmission 61, and Nnin is the rotation speed of the input shaft 65 per unit time. Inm1 is the inertia of the output shaft 50 of MG51, and Inm2 is the inertia of the output shaft 55 of MG52. Note that (dX/dt) (X=Ne, Nnin, Nm1, Nm2) represents the time derivative (amount of change over time).

In this way, the inertia torque calculation unit 11 calculates the inertia torque loss Tine input to the continuously variable transmission 61 from the time changes of each of the rotation speeds Ne, Nnin, Nm1, and Nm2. Therefore, the inertia torque calculation unit 11 can calculate the inertia torque loss according to the running state of the vehicle 9 with high accuracy.

The data storage unit 12 is realized, for example, by a memory. The data storage unit 12 stores map data for calculating the execution time of the backlash elimination control, map data for calculating the fuel cut return torque when the accelerator is on, and the like.

The torque control unit 10 increases the output torque of the engine 2 and MGs 51 and 52 in backlash elimination control. The torque control unit 10 allocates the output torque of the engine 2 and MGs 51 and 52 according to the target torque. Note that the torque control unit 10 may increase only the output torque of MG 51 depending on the driving mode of the vehicle 9, for example. Furthermore, the torque control unit 10 does not control the output torque of MG 52 when, for example, MG 52 is operated as a generator.

Figure 2 is a time chart showing an example of backlash elimination control. Figure 2 shows the accelerator opening detected by the accelerator opening sensor 90, the engine 2 rotation speed Ne (engine rotation speed), the rotation speed Nnin (transmission rotation speed) of the input shaft 65 of the continuously variable transmission 61, the gear ratio of the continuously variable transmission 61, the inertia torque loss, and the change in output torque over time. Here, the output torque is the total torque output from the engine 2 and MGs 51 and 52 to the drive shaft 60.

At time t0, the accelerator of the vehicle 9 is turned on. The accelerator opening starts to increase from 0 and reaches a predetermined value k, at which point it becomes substantially constant. In response to this, the engine speed, the transmission speed, and the gear ratio also increase according to the target torque that corresponds to the predetermined value k of the accelerator opening. Although not shown in the figure, the rotation speeds Nm1 and Nm2 of the MGs 51 and 52 also increase in the same way as the engine speed.

Inertia torque loss increases with the increase in the amount of change over time of each of the rotational speeds Ne, Nnin, Nm1, and Nm2. The amount of change of each of the rotational speeds Ne, Nnin, Nm1, and Nm2 gradually decreases so that they converge to a target value corresponding to the target torque. As the amount of change decreases, the inertia torque loss also decreases.

The torque control unit 10 changes the output torque of the engine 2 from negative to positive during the period from time t0 to t1 so that the driving state of the vehicle 9 transitions from driven driving to driving driving in response to accelerator ON. The torque control unit 10 controls the output torque to the fuel cut return torque during the period from time t0 to t1. The torque control unit 10 calculates the fuel cut return torque based on map data from the output torques of the MGs 51 and 52 and the planetary gear ratio, for example.

Time t1 is the time when the output torque reaches the backlash elimination torque T_loss. The backlash elimination torque T_loss is the output torque when the torque of the drive shaft 60 is substantially 0 (N·m) when taking into account the transmission loss of the gears of the differential mechanism 4 and losses such as friction inside the continuously variable transmission 61. When the output torque becomes equal to or greater than the backlash elimination torque T_loss, the running state of the vehicle 9 transitions from driven running to driving running. The torque control unit 10 starts backlash elimination control when the output torque reaches the backlash elimination torque T_loss.

Next, the torque control unit 10 executes backlash elimination control during the period from time t1 to t2 (backlash elimination time). During backlash elimination control, the torque control unit 10 controls the engine 2 and MGs 51, 52 so that the output torque becomes the sum of the backlash elimination torque T_loss and the inertia torque loss. This compensates for the inertia torque loss, suppressing delays in the backlash elimination timing and completing backlash elimination within the backlash elimination time. Therefore, it is possible to reduce shocks caused by backlash in the gear mechanism when the vehicle 9 changes from driven running to driving running.

When the backlash elimination is completed, the torque control unit 10 increases the output torque to the target torque during the period from time t2 to t3. The amount of change in the output torque over time at this time is determined based on, for example, the inverse of the natural frequency of the hardware of the vehicle 9. This allows the vehicle 9 to accelerate with good responsiveness while suppressing resonance.

Figure 3 is a flowchart showing an example of ECU processing. This processing is executed, for example, at regular intervals when the vehicle 9 is traveling in a fuel-cut state.

First, the torque control unit 10 determines whether the accelerator pedal of the vehicle 9 is on or not based on the detection value of the accelerator pedal position sensor 90 (step St1). If the accelerator pedal of the vehicle 9 is off (No in step St1), the torque control unit 10 ends the process.

When the vehicle 9 is in the access-on state (Yes in step St1), the torque control unit 10 calculates the fuel cut return torque (return torque) Tf (step St2). The torque control unit 10 calculates this from, for example, the output torques of the MGs 51 and 52 and the planetary gear ratio. Next, the torque control unit 10 calculates a backlash-eliminating torque T_loss for eliminating backlash (step St3). The backlash-eliminating torque T_loss is calculated from the gear ratio of the continuously variable transmission 61, the planetary gear ratio, the rotation speed Ne of the crankshaft 20, and the rotation speeds Nm1 and Nm2 of the MGs 51 and 52, taking into account, for example, the transmission loss of the gears of the differential mechanism 4 and the friction inside the continuously variable transmission 61. For the calculation, for example, map data in the data storage unit 12 is used.

Next, the torque control unit 10 compares the fuel cut return torque Tf with the backlash elimination torque T_loss (step St4). If Tf<T_loss holds (No in step St4), the torque control unit 10 controls the engine 2 and the MGs 51 and 52 so that the fuel cut return torque becomes Tf (step St5). Then, the processing from step St2 onwards is executed again.

If Tf≧T_loss is satisfied (Yes in step St4), the torque control unit 10 sets the execution time of the backlash elimination control (backlash elimination time) according to the target torque, the rotation speed Ne of the crankshaft 20, the rotation speeds Nm1 and Nm2 of the MGs 51 and 52, and the gear ratio of the continuously variable transmission 61 (step St6). After setting, the torque control unit 10 measures the execution time of the backlash elimination control using a timer or the like.

Next, the inertia torque calculation unit 11 calculates the inertia torque loss Tine using the above formula (1) (step St7). Next, the torque control unit 10 calculates the total output torque input to the drive shaft from the engine 2 and MGs 51 and 52 as the sum of the latest backlash elimination torque T_loss calculated in step St3 and the inertia torque loss Tine to perform backlash elimination control (step St8).

In this way, the torque control unit 10 corrects the output torque based on the inertia torque loss, so delays in the backlash elimination control due to the inertia torque loss are suppressed. This allows the torque control unit 10 to essentially complete the backlash elimination control within the execution time set in step St6.

Next, the torque control unit 10 determines whether the time being measured has passed the execution time of the backlash elimination control set in step St6 (step St9). If the time being measured has not passed the execution time (No in step St9), the processing from step St7 onwards is executed again. If the time being measured has passed the execution time (Yes in step St9), the torque control unit 10 ends the backlash elimination control and increases the output torque by ΔT (step St10). Here, ΔT is determined based on, for example, the reciprocal of the natural frequency of the hardware of the vehicle 9.

Next, the torque control unit 10 compares the output torque with the target torque (step St11). If the output torque is less than the target torque (No in step St11), the processing from step St10 onwards is executed again. If the output torque is greater than or equal to the target torque (Yes in step St11), the processing ends. In this manner, the ECU 1 executes the processing.

In this example, the engine 2 and MGs 51 and 52 are given as the driving force sources, but even if only one of these is provided as the driving force source, the ECU 1 can execute the above process in the same manner.

The above-described embodiment is a preferred example of the present invention. However, the present invention is not limited to this embodiment, and various modifications are possible without departing from the spirit of the present invention.

1 ECU (control unit)
2. Engine (power source)
9 Vehicle 10 Torque control unit (control unit)
11 Inertia torque calculation unit (calculation unit)
20 Crankshaft (output shaft)
50, 55 Output shaft 51, 52 Motor generator (driving power source)
61 Continuously variable transmission 62 Differential gear (gear mechanism)
63 Drive Wheel

Claims (1)

1. A control device for a vehicle including a continuously variable transmission on a power transmission path between a drive power source and drive wheels, and a gear mechanism on the drive wheel side of the power transmission path,
a control unit that changes an output torque of the driving force source from negative to positive when a traveling state of the vehicle is to be transitioned from a driven traveling state in which power is transmitted from the gear mechanism side to the driving force source side to a driving traveling state in which power is transmitted from the driving force source side to the gear mechanism side, thereby executing backlash eliminating control on the gear mechanism;
a calculation unit that calculates a loss due to an inertia torque input to the continuously variable transmission from a time change in each rotation speed of an output shaft of the driving force source and an input shaft of the continuously variable transmission,
The control unit is a control device that corrects the output torque in the backlash elimination control according to the loss.

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