JP2016047696A - Vehicular control apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To execute drive force control appropriately in consideration of influences of inertia torque associated with a speed change and of torque variation due to fuel-cut control.SOLUTION: A vehicular control apparatus, for use in executing fuel-cut control and drive force control for improving turning performance, performs: calculating a required transmission ratio on the basis of a change amount in an accelerator opening degree and calculating a change amount in forward-reverse acceleration caused both by a change in drive force in the case of ending the fuel-cut control under the required transmission ratio and by a change in drive force associated with changing speeds to the required transmission ratio from a current target transmission ratio under the drive force control, in a case where the fuel-cut control is ended by an accelerator operation during execution of the drive force control and fuel-cut control (step S4); and delaying timing of ending the fuel-cut control in the case of a change amount in the forward-reverse acceleration reaching or exceeding a given value (steps S5, S6).SELECTED DRAWING: Figure 2

Description

  The present invention relates to a vehicle control device that improves turning performance by automatically controlling the driving force of a vehicle.

  Patent Document 1 describes an invention relating to a vehicle driving force control device that executes gear ratio control (corner control) based on information on a corner when the vehicle travels in a corner. The control device described in Patent Document 1 is configured to detect the lateral acceleration of a vehicle and change the timing for returning from corner control based on the amount of change in lateral acceleration and the amount of change in accelerator opening. ing. For example, when the actual change amount of the accelerator opening is smaller than the reference value, the return timing from the corner control is advanced, and the upshift is permitted at an early stage.

  Patent Document 2 describes an invention relating to a vehicle control device including a power unit having an engine and a continuously variable transmission, and power unit control means for switching power characteristics of the power unit for each travel mode. In the control device described in Patent Document 2, when shifting the continuously variable transmission, the engine torque is increased or decreased in a direction to cancel the inertia torque generated on the input side of the continuously variable transmission, and the engine absorbs the inertia torque. The upper limit value of the inertia torque absorbed by the engine is calculated based on the engine operating state and the traveling mode setting state, and the upper limit shift speed at which the inertia torque is generated does not exceed the upper limit value. The continuously variable transmission is configured to shift at a speed change rate.

  Further, Patent Document 3 calculates the driving force of the vehicle based on the output torque of the engine and the gear ratio of the automatic transmission, and stabilizes the behavior of the vehicle when the behavior of the vehicle becomes unstable. An invention related to a vehicle control device that executes behavior control is described. The control device described in Patent Document 2 corrects the driving force of the vehicle in consideration of the effect of inertia torque generated during the shift of the automatic transmission when the automatic transmission is shifting. It is configured.

JP 2009-24739 A JP2013-72456A JP 2003-182409 A

  The control device described in Patent Document 1 is configured to determine the return timing from corner control according to the amount of change in lateral acceleration or accelerator opening generated in the vehicle when the vehicle is turning. . Therefore, the turning state of the vehicle and the driver's acceleration and deceleration intention can be reflected in the control. On the other hand, when the vehicle travels, inertia torque is generated in association with the shift, and when the fuel cut control of the engine is executed, for example, the drive torque fluctuates when returning from the fuel cut control. On the other hand, the control device described in Patent Document 1 does not take into account the above-described inertia torque, torque fluctuation caused by fuel cut control, and the like. Therefore, when corner control is performed during turning, there is a possibility that the driver may be shocked or discomforted due to the influence of torque fluctuations due to inertia torque or fuel cut control.

  The present invention has been devised by paying attention to the above technical problem, and considers the influence of torque fluctuations caused by inertia torque and fuel cut control that occur with a gear shift during turning, and appropriate driving. It is an object of the present invention to provide a vehicle control device capable of executing force control.

  In order to achieve the above object, the present invention provides a vehicle control device that executes engine fuel cut control and driving force control that reduces a driving force by controlling a gear ratio of an automatic transmission during turning. When the fuel cut control is terminated by increasing the accelerator opening by the driver's accelerator operation during execution of the driving force control and the fuel cut control, at least the amount of change in the accelerator opening by the accelerator operation A change in driving force when the fuel cut control is terminated under the required speed ratio, and a current target speed change in the driving power control. The amount of change in the longitudinal acceleration caused by the change in driving force associated with shifting from the ratio to the required speed ratio is obtained. When the amount of change in the longitudinal acceleration exceeds a predetermined value, the control is configured to delay the timing for returning the target speed ratio to the required speed ratio when the fuel cut control is terminated. Device.

  According to the present invention, when the driving force control for improving the turning performance of the vehicle and the fuel cut control of the engine are simultaneously performed, the shift control and the fuel cut in the driving force control are performed by the driver's accelerator operation. When the control is terminated and returned to the normal control state, the change amount of the longitudinal acceleration caused by the end of the shift control and the fuel cut control in the driving force control is estimated. When the amount of change in the longitudinal acceleration is equal to or greater than a predetermined value, it is determined that there is a possibility that the driver may feel uncomfortable or shock due to the large change in the longitudinal acceleration. In this case, therefore, the timing at which the target transmission ratio of the automatic transmission is returned to the required transmission ratio by the driver is delayed in order to end the transmission control and the fuel cut control in the driving force control. That is, the shift at the time of terminating the shift control and the fuel cut control in the driving force control is delayed. Therefore, even if the driver's accelerator operation is performed during the execution of the driving force control and the fuel cut control and the shift control and the fuel cut control in the driving force control are terminated, the driver feels uncomfortable or shocked. Therefore, the shift control and the fuel cut control can be appropriately terminated to return to the normal control state.

It is a schematic diagram showing an example of a configuration of a vehicle and a control system to be controlled in the present invention. It is a flowchart for demonstrating an example of the driving force control by the control apparatus of this invention. It is a time chart for demonstrating the change state of the driving force at the time of performing the driving force control by the control apparatus of this invention. FIG. 4 is a time chart for explaining a driving force change state when the driving force control by the control device of the present invention is not executed as a comparative example of the control example shown in the time chart of FIG. 3.

  Next, an embodiment of the present invention will be described with reference to the drawings. First, the configuration and control system of a vehicle to be controlled in the present invention will be described with reference to FIG. The vehicle targeted by the present invention controls the driving force and braking force of the vehicle independently of driving operations such as accelerator operation and braking operation by the driver, that is, driving of the vehicle based on the driving operation by the driver. Apart from the control of the force and the braking force, the driving force and the braking force can be automatically controlled. A vehicle Ve shown in FIG. 1 has left and right front wheels 1 and left and right rear wheels 2. In the example shown in FIG. 1, the vehicle Ve is configured as a rear wheel drive vehicle that drives the rear wheels 2 with power output from the engine 3.

  The engine 3 is provided with an electronically controlled throttle valve or an electronically controlled fuel injection device, for example. Accordingly, the output of the engine 3 can be automatically controlled by electrically controlling the operation of the electronically controlled throttle valve or the electronically controlled fuel injection device.

  An automatic transmission 4 is provided on the output side of the engine 3 to shift the output torque of the engine 3 and transmit it to the rear wheel 2 side, which is a drive wheel. As the automatic transmission 4, for example, a stepped transmission using a planetary gear mechanism and a friction engagement device, a belt-type continuously variable transmission, or the like is used. In any case, the automatic transmission 4 is provided with a hydraulic control device (not shown) for executing the shift operation. And it is comprised so that the gear ratio set with the automatic transmission 4 can be controlled automatically by electrically controlling operation | movement of the solenoid valve etc. in the hydraulic control apparatus.

  An electronic control unit (ECU) 5 for controlling the output of the engine 3 and the operation of the automatic transmission 4 is provided. That is, the ECU 5 is electrically connected to the engine 3. Further, the ECU 5 is electrically connected to the automatic transmission 4 via a hydraulic control device. By controlling the operation of the automatic transmission 4 by the ECU 5, the automatic transmission 4 is configured to execute shift control for setting a predetermined gear stage or gear ratio. Therefore, by controlling the output of the engine 3 and the gear ratio of the automatic transmission 4 by the ECU 5, it is possible to automatically control the driving force of the vehicle Ve generated by the rear wheels 2, that is, the driving wheels. Yes.

  Further, each of the wheels 1 and 2 is individually equipped with brake devices 6 and 7, respectively. Each of the brake devices 6 and 7 is connected to the ECU 5 via a brake actuator 8. Therefore, by controlling the brake actuator 8 by the ECU 5 and controlling the operation of the brake devices 6, 7, the braking force of the vehicle Ve generated by the wheels 1, 2 can be automatically controlled individually. It has become.

  On the other hand, the ECU 5 is configured to receive detection signals from various sensors of various parts of the vehicle Ve and information signals from various in-vehicle devices. For example, an accelerator sensor 9 that detects an accelerator depression angle (or depression amount or accelerator opening), a brake sensor 10 that detects a brake depression angle (or depression amount), and a steering angle sensor 11 that detects a steering angle of a steering wheel. , A wheel speed sensor 12 for detecting the rotational speed (wheel speed) of each wheel 1, 2, a longitudinal acceleration sensor 13 for detecting acceleration (longitudinal acceleration) in the longitudinal direction (vertical direction in FIG. 1) of the vehicle Ve, vehicle A lateral acceleration sensor 14 that detects acceleration (lateral acceleration) in the axle direction of Ve (lateral direction in FIG. 1), a yaw rate sensor 15 that detects the yaw rate of the vehicle Ve, or a torque sensor that detects output torque of the engine 3 (FIG. (Not shown) or the like is input to the ECU 5.

  The driving force automatically controlled in the present invention includes a positive driving force for driving the vehicle Ve and a negative driving force for braking the vehicle Ve, that is, a braking force. For example, when the driving force is changed by a negative control amount, the gear ratio is changed so that the driving torque of the vehicle Ve decreases. Alternatively, when the braking force has already been generated by the engine braking force or the like, the gear ratio is changed so that the braking force increases. On the other hand, when changing the driving force by the control amount in the positive direction, the gear ratio is changed so that the driving torque of the vehicle Ve increases. Alternatively, when the braking force is already generated by the engine braking force or the like, the gear ratio is changed so that the braking force is reduced.

  With the configuration as described above, the vehicle Ve can control the steering characteristics and the stability factor. In particular, the vehicle Ve in the present invention is configured to improve the steering characteristics during turning while improving the turning performance of the vehicle Ve. For example, the vehicle speed and the road surface friction coefficient are estimated from the wheel speeds of the wheels 1 and 2 detected by the wheel speed sensor 12, and the vehicle is based on the vehicle speed, the road surface friction coefficient, the steering angle detected by the steering angle sensor 11, and the like. It is possible to set a target steering characteristic that is a target of Ve and perform control that causes the actual steering characteristic of the vehicle Ve to follow the target steering characteristic.

  Specifically, the actual steering characteristic of the vehicle Ve can be brought close to the target steering characteristic by changing the driving force and the braking force of the vehicle Ve to control the yaw rate of the vehicle Ve. When controlling the yaw rate of the vehicle Ve, the target yaw rate of the vehicle Ve at that time is obtained based on information such as the vehicle speed, the steering angle, and the wheel base. Then, by controlling the driving force of the vehicle Ve as described above, the yaw rate of the vehicle V can be controlled so that the actual yaw rate of the vehicle Ve approaches the target yaw rate. For example, the yaw rate of the vehicle Ve is controlled by increasing or decreasing the correction torque with respect to the driving torque applied to the rear wheel 2 or the braking torque applied to the wheels 1 and 2. Can do.

  As described above, a control technique for setting the target yaw rate and causing the actual yaw rate of the vehicle Ve to follow the target yaw rate is described in, for example, Japanese Patent Laid-Open No. 5-278488. Also, for example, Japanese Patent Application Laid-Open No. 2005-256636 describes a control technique for controlling the driving force of driving wheels so that the vehicle stability factor follows a target value. Alternatively, Japanese Patent Application Laid-Open No. 2011-218953 describes a control technique for controlling the driving force of the drive wheels so that the steering characteristic of the vehicle follows the target steering characteristic. As described above, since the basic control contents of the driving force control for automatically controlling the driving force of the vehicle to stabilize the behavior and posture of the turning vehicle are well known by the above-mentioned patent documents, Then, more specific explanation is omitted.

  As described above, in the driving force control for improving the turning performance of the vehicle Ve, when the driving force of the vehicle Ve is reduced, the automatic transmission 4 performs a shift, and therefore the gear ratio changes. Along with this, an inertia torque occurs. Further, when turning, the frequency at which the accelerator pedal is depressed for deceleration increases. Therefore, the fuel cut control of the engine 3 may be executed together with the driving force control. When the driving force control and the fuel cut control are executed in parallel, for example, when the fuel cut control of the engine 3 is ended by the driver depressing the accelerator pedal, the driving force is returned when returning from the fuel cut control. Changes. Therefore, when the driving force control is executed, if the driving force changes caused by the inertia torque and the fuel cut control accompanying the shift as described above overlap, the fluctuation of the torque becomes large, which causes the driver to change. There was a possibility of giving a sense of incongruity.

  Therefore, in the vehicle control device according to the present invention, when executing the driving force control as described above, the driver feels shock or discomfort in consideration of the torque fluctuation caused by the inertia torque and the fuel cut control accompanying the shift. In order to appropriately execute the control without giving the control, the following control is executed.

  FIG. 2 is a flowchart for explaining an example of the control, and the routine shown in this flowchart is repeatedly executed every predetermined short time. First, in step S1, it is determined whether or not the shift control in the driving force control for improving the turning traveling performance is being executed. For example, when the difference between the control target driving force in the driving force control and the driver's requested driving force based on the vehicle speed and the accelerator opening is equal to or greater than a predetermined value, the shift control in the driving force control is being executed. Judgment can be made. Alternatively, it is possible to determine whether or not the shift control in the driving force control is being executed from the value of the control operation flag that is turned on when the shift control in the driving force control is started.

  If a negative determination is made in step S1 because the shift control in the driving force control is not being executed, this routine is temporarily terminated without executing the subsequent control. On the other hand, when the shift control in the driving force control is being executed, if the determination in step S1 is affirmative, the process proceeds to step S2.

  In step S <b> 2, it is determined whether or not to shift to a termination process stage for ending the shift control in the driving force control. This determination is made based on the driver's accelerator operation. For example, when the accelerator opening is equal to or greater than a predetermined value set as the threshold value, it is determined that the shift control in the driving force control is shifted to the end process stage.

  For example, when there is no driver's accelerator operation, or when the accelerator opening is less than a predetermined value, it is determined that it is not yet the stage to proceed to the end processing. That is, a negative determination is made in step S2, and the control in step S2 is repeated. On the other hand, for example, if the accelerator opening is equal to or greater than a predetermined value, and a positive determination is made in step S2, the process proceeds to step S3.

  In step S3, it is determined whether or not the shift in the driving force control is a downshift. For example, when the difference between the control target speed ratio or the current speed ratio in the speed change control and the required speed ratio for realizing the required drive force is equal to or greater than a predetermined value, the speed change in the drive force control is reduced. It can be determined that this is a shift. If the shift in the driving force control is a downshift, and if the determination in step S3 is affirmative, the process proceeds to step S4.

  In step S4, it is determined whether or not the shift control end interruption process in the driving force control can be executed. Specifically, the longitudinal acceleration change amount G_te of the vehicle Ve is calculated from the change amount of the engine torque caused by the driver's accelerator operation, and the longitudinal acceleration change amount G_te determines whether or not the driver feels uncomfortable. Is compared with a threshold value Gx_max. The amount of change in the engine torque in this case is the inertia torque generated by the change of the gear ratio when the shift control in the driving force control is terminated, and the fuel cut control is executed in parallel during the execution of the driving force control. In such a case, the change is determined in consideration of the change in the drive torque caused by the fuel cut control being terminated by the driver's accelerator operation. Therefore, the above-described longitudinal acceleration change amount G_te is calculated in consideration of the torque change caused by the end of the inertia torque and the fuel cut control caused by the change in the gear ratio.

  If the longitudinal acceleration change amount G_te is equal to or greater than the threshold value Gx_max, the shift control end interruption process in the driving force control is executed. That is, the end of the shift control in the driving force control is interrupted. In this case, since the longitudinal acceleration change amount G_te is large, it is determined that if the shift control in the driving force control is terminated in this state, it is highly likely that the driver will feel uncomfortable or shocked. Therefore, the shift control end interruption process in the driving force control is executed.

  On the other hand, when the longitudinal acceleration change amount G_te is less than the threshold value Gx_max, the shift control end interruption process in the driving force control is prohibited. In this case, since the longitudinal acceleration change amount G_te is small, it is determined that even if the shift control in this driving force control is terminated, the driver is unlikely to feel uncomfortable or shocked. Therefore, the shift control end interruption process in the driving force control is not executed. That is, the end of the shift control in the driving force control is executed immediately without being interrupted.

  When the calculated longitudinal acceleration change amount G_te is smaller than the threshold value Gx_max, if the determination in step S4 is affirmative, the process proceeds to step S5, and the shift control end interruption process in the driving force control is executed. The That is, the end of the shift control in the driving force control is delayed. Specifically, the shift control end interruption process in the driving force control is executed until the timer is turned ON and the count value T of the timer reaches a predetermined time T_limit. Then, when the count value T becomes equal to or longer than the predetermined time T_limit, the process shifts to an end (return) process of the shift control in the driving force control. When the shift interruption end process in the driving force control is executed in step S5, the process proceeds to step S6.

  In step S6, it is determined whether or not the shift control end (return) process in the driving force control can be executed. Specifically, it is determined whether or not the count value T of the timer has reached a predetermined time T_limit or more. If the count value T is still less than the predetermined time T_limit and thus a negative determination is made in step S6, the process returns to step S5. And control of step S5 and this step S6 is repeated. On the other hand, when the count value T is equal to or longer than the predetermined time T_limit and the determination is affirmative in step S6, the process proceeds to step S7.

  On the other hand, if it is negatively determined in step S3 described above that the shift in the driving force control is not a downshift, and in step S4 described above, it is negative if the longitudinal acceleration change amount G_te is less than the threshold value Gx_max. If it is determined in step S7, the process proceeds to step S7.

  In step S7, a shift control end (return) process in the driving force control is executed. For example, in the above-mentioned step S4, when the longitudinal acceleration change amount G_te is less than the threshold value Gx_max, the shift control end interruption process in the driving force control is prohibited, that is, the end (return) of the shift control in the driving force control. ) Is executed immediately without being interrupted, it is determined that the gear ratio can be changed by the difference between the longitudinal acceleration change amount G_te and the threshold value Gx_max. Therefore, the shift control is terminated so that the change in the gear ratio is such that the change in the longitudinal acceleration is within the range of the difference. Alternatively, when the shift control end (return) process in the driving force control is executed because the time equal to or longer than the predetermined time T_limit has passed in the above-described step S5 and step S6, a predetermined predetermined end is set. In the method, the shift control is terminated. For example, the shift control is performed so that the driver can change the gear ratio so that the change in the longitudinal acceleration is within the range where the driver does not feel a sense of incongruity or shock due to the change in the longitudinal acceleration caused by the change in the gear ratio. Is terminated.

  When the shift control end (return) process in the driving force control is executed in step S7, it is then determined whether or not the shift control end (return) process in the drive force control is completed (step S7). S8). Specifically, when the control target speed change ratio of the previous value is larger than the driver's required speed change ratio, the current control target speed change ratio becomes smaller than the driver's required speed change ratio. It is determined that the shift control end (return) process has been completed. In addition, when the control target speed change ratio of the previous value is smaller than the driver required speed change ratio, the current control target speed change ratio becomes larger than the driver required speed change ratio. It is determined that the end (return) processing is completed.

  If it is determined that the shift control end (return) process in the driving force control has not yet been completed, and therefore a negative determination is made in step S8, the process returns to step S7. And control of step S7 and this step S8 is repeated. On the other hand, if it is determined that the shift control end (return) process in the driving force control has been completed, and if the determination in step S8 is affirmative, this routine is temporarily ended.

  The change state of the driving force of the vehicle Ve when the driving force control as described above is executed is shown in the time chart of FIG. As a comparative example, a change state of the driving force of the vehicle Ve when the driving force control in the present invention is not executed is shown in the time chart of FIG. In the time chart of FIG. 3, when steering is performed at time t1 and the steering angle increases, the driving force control in the present invention is started. Specifically, the gear ratio in the automatic transmission 4 is increased so that the braking force (engine brake) of the vehicle Ve increases, that is, the driving force decreases. In the example shown in FIG. 3, the control target input rotational speed in this driving force control is increased with respect to the required input rotational speed based on the driver's required driving force.

  Further, when the driving force control is started as described above, the actual actual driving force of the vehicle Ve is reduced. In the example shown in FIG. 3, the actual driving force is reduced by this driving force control, and the reduction is already started by executing the fuel cut control based on the accelerator opening being fully closed. Has been.

  Thereafter, at time t2, the fuel cut control is ended by the driver's accelerator operation (accelerator ON). At the same time, control for ending the shift control in the driving force control, that is, control for returning from the shift control in the driving force control to the normal shift control based on the driver's requested driving force is started.

  In the control for ending the shift control in the driving force control, an end (return) process for ending the shift control after a predetermined time T_limit elapses from time t2 when the accelerator is turned on and at time t3a. Interrupted. That is, the end of the shift control is delayed.

  The time chart of FIG. 4 shows that the vehicle Ve is driven when the driving force control in the present invention as described above is not executed, that is, when the control for delaying the end of the shift control is not executed as described above. The change of force is shown. In this case, at time t2, the fuel cut control is terminated by the accelerator ON, and the shift control in the driving force control is immediately terminated. Specifically, immediately after time t2, the control target input rotational speed is lowered so as to coincide with the requested input rotational speed. Along with this, the actual driving force of the vehicle Ve is greatly changed in the increasing direction. When the transmission control in the driving force control is finished, the transmission gear ratio is changed. As a result, the inertia torque is generated by the change of the input rotation speed, and the fluctuation of the driving force corresponding thereto is generated. In addition, when the fuel cut control is terminated, the engine torque increases, and the driving force fluctuates accordingly. For this reason, large fluctuations in driving force occur due to torque fluctuations that include the inertia torque due to the change in the gear ratio and the torque change due to the end of the fuel cut control.

  In contrast, in the driving force control according to the present invention, as described above, the end of the shift control in the driving force control is delayed while the predetermined time T_limit elapses, so that the driving force generated when the shift control is ended. Fluctuations are suppressed. Therefore, it is possible to suppress the driver from feeling shocked or uncomfortable when executing the driving force control for improving the turning performance of the vehicle Ve.

  DESCRIPTION OF SYMBOLS 3 ... Engine, 4 ... Automatic transmission (transmission), 5 ... Electronic control unit (ECU) 6, 7 ... Brake device, 9 ... Accelerator sensor, 10 ... Brake sensor, 11 ... Steering angle sensor, 12 ... Wheel speed Sensor 13 longitudinal acceleration sensor 14 lateral acceleration sensor 15 yaw rate sensor Ve vehicle

Claims (1)

In a control device for a vehicle that executes fuel cut control of an engine and driving force control that reduces the driving force by controlling a gear ratio of an automatic transmission during turning traveling,
During the execution of the driving force control and the fuel cut control, when the fuel cut control is terminated by increasing the accelerator opening by the accelerator operation of the driver,
Determining a required speed change ratio for realizing the driver's required driving force based on a change amount of the accelerator opening at least by the accelerator operation;
This is due to a change in driving force when the fuel cut control is terminated under the required speed ratio, and a change in driving force accompanying a shift from the current target speed ratio to the required speed ratio in the driving force control. The amount of longitudinal acceleration change
When the amount of change in the longitudinal acceleration is greater than or equal to a predetermined value, the timing for returning the target gear ratio to the required gear ratio is delayed when the fuel cut control is terminated. Vehicle control device.

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