Vehicle control device

Abstract

Provided is a vehicle control device that can prevent unintended acceleration of the vehicle even when the operating condition of the operation switch for the EPB is unknown during the driving force limitation accompanied by the operation of the dynamic EPB. The vehicle control device includes: an engine (11) that generates driving torque for the vehicle; a hydraulic brake (14) that applies braking force to the wheels of the vehicle; a FI-ECU (12) that controls the driving torque generated by the engine (11); a braking force control device (13) that controls the braking force of the hydraulic brake (14); and an EPB switch (15) that indicates the operation of the electronic parking brake (18a). The FI-ECU (12) performs driving force limitation control for limiting the driving torque based on the operation indication status of the EPB switch (15). When the operation indication status of the EPB switch (15) is unknown during the implementation of the driving force limitation control, the driving force limitation control is continuously performed regardless of the operation indication status of the EPB switch (15).

Description

Technical Field

[0001] The present invention relates to a vehicle control device. Background Art

[0002] Patent Document 1 discloses that when an operation switch for an electronic parking brake (EPB) is operated during the running of a vehicle, braking force is applied to the vehicle to limit the driving force (dynamic EPB).

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Patent No. 6519536 Gazette Summary of the Invention

[0006] However, in the technology of Patent Document 1, when the driving force is limited (the actual acceleration opening is reduced) along with the operation of the dynamic EPB while the driver is stepping on the accelerator pedal, there is a possibility of a communication failure between the ECU (Electronic Control Unit) of the electronic parking brake and the ECU of the power platform. If such a communication failure occurs, the operation status of the switch for the EPB cannot be grasped, and thus the release time of the driving force suppression control becomes unknown. Here, if the driving force suppression control is canceled (released) as in the normal operation in the case of a device failure (communication obstacle), since the driver is stepping on the accelerator pedal (the actual acceleration opening also becomes larger), the vehicle will accelerate, and there is a possibility of unintended acceleration of the vehicle.

[0007] Therefore, an object of the present invention is to provide a vehicle control device that can prevent unintended acceleration of the vehicle even when the operation status of the operation switch for the EPB is unknown during the driving force limitation accompanying the operation of the dynamic EPB.

[0008] The vehicle control device of the present invention is characterized by having: a drive source that generates driving torque for the vehicle; a braking device that applies braking force to the wheels of the vehicle; a drive torque control unit that controls the driving torque generated by the drive source; a braking force control unit that controls the braking force of the braking device; an EPB operation instruction unit that instructs the operation of the electronic parking brake; and an EPB operation unit that has the electronic parking brake and operates the electronic parking brake in response to the EPB operation instruction unit. The drive torque control unit implements driving force limitation control for limiting the driving torque based on the operation instruction status of the EPB operation instruction unit. When the operation instruction status of the EPB operation instruction unit is unknown during the implementation of the driving force limitation control, the driving force limitation control is continuously performed regardless of the operation instruction status of the EPB operation instruction unit.

[0009] Effect of the Invention

[0010] According to the present invention, a vehicle control device can be provided, which can prevent the vehicle from accelerating unintentionally even when the operation state of the operation switch (EPB operation indication unit) for the EPB is unknown during the driving force limitation accompanied by the operation of the dynamic EPB. Description of the Drawings

[0011] Figure 1 It is a system configuration diagram of a vehicle control device according to an embodiment of the present invention.

[0012] Figure 2 It is a timing diagram of each part of the vehicle control device according to an embodiment of the present invention.

[0013] Figure 3 It is a flowchart of the drive torque control unit of the vehicle control device according to an embodiment of the present invention.

[0014] Description of Reference Numerals

[0015] 1 Vehicle control device

[0016] 11 Engine (drive source)

[0017] 12 FI-ECU (drive torque control unit)

[0018] 13 Brake control device (braking force control unit)

[0019] 14 Hydraulic brake (brake device)

[0020] 15 EPB switch (EPB operation indication unit)

[0021] 16 Accelerator pedal (acceleration operation element) Detailed Description of the Invention

[0022] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0023] Figure 1 It is a system configuration diagram of a vehicle control device according to an embodiment of the present invention. The vehicle control device 1 has a FI-ECU 12 (drive torque control unit) that controls the drive torque of the engine 11, and the engine 11 is a drive source that generates drive torque for the vehicle. That is, the FI-ECU 12 sends a power platform driving force instruction to the engine 11 to control the driving force generated by the engine 11. This vehicle is a gasoline vehicle with only an engine as the drive source, but it can also be configured as an electric vehicle (including a fuel cell vehicle) with only a motor as the drive source, or a hybrid vehicle with both a motor and an engine as the drive source.

[0024] The braking control device 13 (braking force control section) controls the braking force of a braking device that applies braking force to the wheels of the vehicle, i.e., the hydraulic brake 14. In addition, the braking control device 13 operates an electronic parking brake device 18 (EPB operation section) having an electronic parking brake (actual braking section; braking factor) 18a. Specifically, by operating an EPB switch 15 (EPB operation instruction section) provided in the vehicle interior, EPB switch operation information is sent to the braking control device 13. Thereby, a work request is sent from the braking control device 13 to the electronic parking brake device 18 to operate the electronic parking brake 18a.

[0025] Accelerator pedal opening information output from an accelerator pedal 16 (acceleration operation element) is output to the FI-ECU 12 and the braking control device 13.

[0026] If the EPB switch 15 is operated during vehicle travel, dynamic EPB control is performed. That is, the braking control device 13 applies braking force through the hydraulic brake 14 (dynamic EPB braking control). In addition, the braking control device 13 sends the content of the established dynamic EPB pressurization flag to the FI-ECU 12 to implement drive torque limit control (reducing the actual acceleration opening) that limits the drive torque of the engine 11, and this dynamic EPB pressurization flag indicates that braking force is being applied by the dynamic EPB.

[0027] The braking control device 13 has a CAN transceiver 13a and sends an EPB status reporting whether the EPB switch 15 is operated to the FI-ECU 12 via CAN (Controller Area Network).

[0028] The FI-ECU 12 has a CAN transceiver 12a and receives the EPB status reporting whether the EPB switch 15 is operated from the braking control device 13 via CAN. When the operating condition of the EPB switch 15 is unknown during the implementation of the drive torque limit control, the drive torque limit control is continuously performed regardless of the operating condition of the EPB switch 15. The situation where the operating condition of the EPB switch 15 is unknown means a situation where the EPB status cannot be transmitted to the FI-ECU 12 due to a CAN failure, etc., and also includes a situation where a state where it is detected that information cannot be normally received within a fixed time due to a disconnection or short circuit of the communication path, a failure of the transmitter or receiver, or a communication obstacle based on external noise. In addition, as the EPB status, the following three statuses are sent digitally: switch pressed: EPB release instruction; switch pulled up: EPB operation instruction; switch not operated: operation / release instruction continues.

[0029] Figure 3This is a flowchart showing the operation of the FI-ECU 12, which detects CAN reception anomalies (communication obstacles including communication failures) from the brake control device.

[0030] In step S1, the FI-ECU 12 determines whether a fixed time (a period sufficiently longer than the normal time interval) has elapsed since the last reception. If so, it determines that there is a CAN failure including a communication obstacle. If not, that is, when a long period of time has not elapsed since the last reception, in step S2, the FI-ECU 12 determines the anomaly of the checksum of the received data. In the case of an anomaly (yes), in step S5, it is determined that there is a CAN reception anomaly (communication obstacle including communication failure). If not, in step S3, the FI-ECU 12 determines the anomaly of the alive counter value. That is, alive data is continuously transmitted at a specified time. In the case (yes) where no alive data is received after a specified time has elapsed in the non-communication state, it is determined to be abnormal (step S5). That is, in step S5, it can be determined that the operation instruction status of the EPB operation instruction unit is unknown. If not, it is determined that the communication is normal (step S4).

[0031] Next, during the period when the FI-ECU 12 detects the operation of the accelerator pedal 16 by the driver and when the operation status of the EPB switch 15 is detected as unknown during the implementation of the driving force limit control, then after the operation of the accelerator pedal 16 is released, the driving force limit control is released.

[0032] When the operation status of the EPB switch 15 is released, or when the accelerator pedal 16 is operated again after the operation of the accelerator pedal 16 is released, the dynamic EPB braking control is released.

[0033] Next, a specific example of the operation of the vehicle control device 1 will be described. Figure 2 This is a timing diagram of each part of the vehicle control device 1. "EPB switch operation" indicates ON and OFF of the EPB switch 15. "AP (accelerator pedal) opening" is the opening of the accelerator pedal 16. The FI-ECU 12 receives the opening of the accelerator pedal 16 actually depressed by the driver, that is, the DrAP (accelerator pedal) opening ( Figure 2 of the single dotted line), and the FI-ECU 12 generates (calculates): the adjusted AP (accelerator pedal) opening ( Figure 2 of the solid line) to be treated as the current accelerator pedal opening for (electronic) control from the DrAP; and the control AP opening ( Figure 2 of the dotted line).

[0034] When the FI-ECU 12 detects a CAN reception abnormality (communication obstacle including communication failure) as described above, it generates a "CAN failure flag", which indicates whether there is a failure (communication obstacle) based on the CAN-based EPB state ( Figure 1 ).

[0035] The "EPB state" indicates the condition of the EPB state ( Figure 1 ).

[0036] The "braking force" means the hydraulic braking force of the hydraulic brake 14 and the parking braking force of the electronic parking brake 18a of the electronic parking brake device 18.

[0037] The "vehicle speed" displays the speed of the vehicle, and the vertical axis represents the magnitude of the speed.

[0038] In this timing chart, it shows the case where the EPB switch 15 is initially ON (pull-up operation). Thus, even if the DrAP opening is a high value, the adjusted (regulated) AP opening is 0, and the driving force limit control is implemented. In addition, the hydraulic braking force is also increased to implement the dynamic EPB braking control. As a result, the vehicle speed decelerates.

[0039] Subsequently, a CAN failure occurs, and the EPB state fails to be transmitted to the FI-ECU 12. For the FI-ECU 12, the condition of the EPB state is unknown. At this time, when the FI-ECU 12 detects that the condition of the EPB state is unknown, it sets the CAN failure flag through the FI-ECU 12. However, the FI-ECU 12 keeps the AP opening at 0 even after adjustment (regulation) and continues the driving force limit control. That is, through the vehicle control of this embodiment, it is possible to prevent the vehicle from accelerating unintentionally.

[0040] Then, as Figure 2 shown, if the EPB switch 15 is set to OFF, the hydraulic braking force, that is, the dynamic EPB braking control is released (the braking force is 0 as Figure 2 shown).

[0041] Then, if the operation of the accelerator pedal 16 by the driver is released and the DrAP opening becomes 0 for example, the driving force limit control is released. As a result, the control AP (accelerator pedal) opening increases.

[0042] As the basic control, the control AP opening is always the upper limit value. As the adjusted AP opening ( Figure 2 solid line), the smaller value of the control AP opening ( Figure 2 dashed line) and the DrAP opening ( Figure 2 dash-dotted line) is adopted. Thus, even if the driver steps on the accelerator pedal 16, the suppression of the AP opening is achieved.

[0043] When the operation of the driver's accelerator pedal 16 is released, if the control AP opening smoothly rises, then when the driver subsequently steps on the accelerator pedal 16, the control AP opening (adjusted AP opening) is adopted as the smaller value between the control AP opening and the DrAP opening. Therefore, in the case where the accelerator pedal 16 is stepped on quickly compared to the recovery of the control AP opening that proceeds smoothly as described above, the control AP opening (adjusted AP opening) will become the smaller value, and the output equivalent to the DrAP opening (the driving force cannot be generated). Thus, by setting the control AP opening to the upper limit value at the time when the control AP opening is greater than the DrAP opening, the value of the DrAP opening can be output (a driving force equivalent to the value of the opening can be generated).

[0044] According to the vehicle control device 1 described above, when the driving force limitation accompanied by the dynamic EPB operation is in progress, even if the operation status of the EPB switch 15 is unknown (a communication failure occurs), the driving force limitation is continuously performed, thereby being able to suppress the unintended acceleration of the vehicle.

[0045] In addition, if the driver releases the accelerator pedal 16, or then steps on the accelerator pedal 16 again (the driver has the intention to accelerate), the driving force suppression control is released, and thus acceleration can be performed in accordance with the driver's intention.

[0046] In addition, when the EPB switch 15 is set to OFF, or the dynamic EPB braking control is released by stepping on the accelerator pedal again. Thereby, it is possible to prevent being involved in braking when the driver has the intention to accelerate.

[0047] Furthermore, the braking is not limited to a hydraulic brake, and can also be a mechanical brake, or multiple braking methods can be used.

[0048] In addition, although the EPB pressurization flag is used, it can also be that the state includes the dynamic EPB state, and when this state is received, the driving force limitation is performed.

Claims

1. A vehicle control device, characterized in that, comprising: a drive source that generates driving torque for the vehicle; a braking device that applies braking force to the wheels of the vehicle; a driving torque control unit that controls the driving torque generated by the drive source; a braking force control unit that controls the braking force of the braking device; an EPB operation instruction unit that instructs the operation of the electronic parking brake; and an EPB operation unit that has the electronic parking brake and operates the electronic parking brake in response to the EPB operation instruction unit; the driving torque control unit implements driving force limit control for limiting the driving torque based on the operation instruction status of the EPB operation instruction unit; when the operation instruction status of the EPB operation instruction unit is unknown during the implementation of the driving force limit control, the driving force limit control is continuously performed regardless of the operation instruction status of the EPB operation instruction unit; during the operation of the acceleration operation element and when the operation instruction status of the EPB operation instruction unit is unknown during the implementation of the driving force limit control, the driving force limit control is released after the operation of the acceleration operation element is released.

2. The vehicle control device according to claim 1, wherein: the operation instruction status of the EPB operation instruction unit is sent to the driving torque control unit via the braking force control unit; the situation where the operation instruction status of the EPB operation instruction unit is unknown occurs due to either a communication failure or a communication obstacle between the braking force control unit and the driving torque control unit.

3. The vehicle control device according to claim 1, wherein: the braking force control unit implements dynamic EPB braking control for applying the braking force to the wheels based on the operation instruction status of the EPB operation instruction unit during vehicle travel; the dynamic EPB braking control is released when the operation instruction status of the EPB operation instruction unit is released or when the acceleration operation element is operated again after the operation of the acceleration operation element is released.

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