Vehicle control system

Abstract

To make a behavior of a vehicle in a case where acceleration operation is performed more safe and along an intention of a driver after actuation of an automatic brake.SOLUTION: A vehicle control device comprises: obstacle detection means which detects existence of a front obstacle; automatic brake control means which holds brake force to prescribed timing after automatically generating brake force of a vehicle when there is a possibility of collision with an obstacle (time t1); and engine torque suppression means which suppresses increase in engine torque with respect to acceleration operation by a driver under a prescribed condition when the obstacle continuously exists after generation of brake force. The automatic brake control means releases holding of brake force when the acceleration operation is performed after generation of brake force, and sets timing of releasing holding of brake force after the acceleration operation to timing later than other torque suppression non-execution time (time t7) in the torque suppression execution time (time t4).SELECTED DRAWING: Figure 7

Description

Technical Field

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

Background Art

[0002] A collision damage mitigation brake aimed at reducing damage during a collision is known.

[0003] Patent Document 1 discloses a technique for avoiding an unintended start of a vehicle that is not based on the driver's intention after stopping by an emergency brake. Specifically, after stopping by an emergency brake, when a re-pressing operation of the accelerator pedal, in other words, a stepping-up operation via the fully-closed state of the accelerator pedal, is detected, the operation of the emergency brake is released. That is, after stopping by an emergency brake, it is confirmed by detecting a re-pressing operation of the accelerator pedal that the accelerator operation by the driver is based on the driver's own intention to start or accelerate.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Here, it is required to control the behavior of the vehicle when there is an accelerator operation by the driver after the operation of the collision damage mitigation brake so that it is safer and in line with the driver's intention.

[0006] According to the technique described in the above-mentioned Document 1, by detecting a re-pressing operation of the accelerator pedal, the driver's intention can be confirmed, and a certain effect can be expected in achieving behavior in line with the driver's intention.

[0007] However, if the emergency brake is released after an emergency stop due to an obstacle such as a preceding vehicle, based on the detection of the driver pressing the accelerator pedal again, the driver may panic due to the sudden activation of the emergency brake and mistakenly press the accelerator pedal again. In such a case, the emergency brake would be released regardless of the presence of an obstacle ahead, allowing the vehicle to restart.

[0008] On the other hand, in order to prevent accidental acceleration due to incorrect accelerator operation when there is an obstacle in the vehicle's path, there is also a known technology that suppresses the increase in engine torque when the accelerator pedal is pressed hard in the presence of an obstacle in the vehicle's path.

[0009] Here, if we consider a scenario where emergency braking is activated while driving uphill in the presence of an obstacle ahead, the presence of the obstacle will suppress the increase in engine torque when restarting after coming to a stop. Therefore, if the emergency braking is released upon detection of the accelerator pedal being pressed again, there is a concern that the vehicle may roll backward due to insufficient engine torque.

[0010] Therefore, the present invention aims to provide a vehicle control device that can make the vehicle's behavior safer and more in line with the driver's intentions when the accelerator is pressed after braking by automatic brake control. [Means for solving the problem]

[0011] To solve the aforementioned problems, a vehicle control device according to one embodiment of the present invention includes: an obstacle detection means for detecting the presence of an obstacle in the direction of travel of the vehicle; an automatic brake control means for determining whether there is a possibility of collision with the obstacle, and if there is a possibility of collision, automatically generating a braking force for the vehicle and then performing automatic brake control to maintain the braking force until a predetermined time; and, if the obstacle continues to exist after the generation of the braking force, increasing the engine torque in response to the accelerator operation by the driver. Below a specified vehicle speed and above a specified accelerator opening.The automatic brake control means includes an engine torque suppression means that implements starting torque suppression control to suppress the braking force, and after the generation of the braking force, if the driver operates the accelerator, the automatic brake control means releases the holding of the braking force, and sets the timing of releasing the holding of the braking force after the accelerator operation to a later time when torque suppression is implemented and the starting torque suppression control is implemented, than at other times when torque suppression is not implemented. [Effects of the Invention]

[0012] According to the present invention, it is possible to make the vehicle's behavior safer and more in line with the driver's intentions when the accelerator is pressed after braking by automatic brake control. [Brief explanation of the drawing]

[0013] [Figure 1] This is a schematic diagram showing the overall configuration of a vehicle control device according to one embodiment of the present invention. [Figure 2] This flowchart shows the overall flow of automatic brake control performed by the vehicle control device according to the same embodiment. [Figure 3] This flowchart shows the contents of the brake force retention release process performed by the vehicle control device according to the same embodiment. [Figure 4] This flowchart shows the contents of the collision possibility detection process performed by the vehicle control device according to the same embodiment. [Figure 5] This flowchart shows the contents of the unintended acceleration detection process performed by the vehicle control device according to the same embodiment as described above. [Figure 6] This graph shows the relationship between the time it takes for the tilt angle sensor to stabilize after stopping due to automatic braking control (sensor stabilization time ΔTstb) and the absolute value of the deceleration (|DCL|). [Figure 7] This is a time chart showing the operation of a vehicle control device according to one embodiment of the present invention. [Modes for carrying out the invention]

[0014] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0015] FIG. 1 is a schematic diagram showing the overall configuration of a vehicle control device 1 according to an embodiment of the present invention.

[0016] The vehicle control device 1 according to the present embodiment includes an engine controller 101, a brake controller 201, and a collision damage mitigation brake controller (hereinafter referred to as “AEB controller”) 301. In the present embodiment, the vehicle uses an internal combustion engine (hereinafter simply referred to as “engine”), not shown, as a driving source for traveling. The vehicle is not limited thereto, and may be an electric vehicle having an electric motor as a driving source, or a hybrid vehicle having an engine and an electric motor as driving sources.

[0017] The engine controller 101 controls the operation of the engine. The control targets of the engine controller 101 include a fuel injector 121. The engine controller 101 reads various sensor output information indicating the operating state of the engine, and performs a predetermined calculation based on this information. Then, the actuator operation amount that is the result of the calculation is output to a predetermined engine control device. For example, the engine controller 101 calculates the fuel supply amount to the engine, and outputs a fuel injector operation amount corresponding to the fuel supply amount to the fuel injector 121. The fuel injector 121 operates according to the fuel injector operation amount, and supplies an amount of fuel corresponding to the fuel supply amount to the engine.

[0018] The engine controller 101 inputs, as sensor output information for the basis of calculations, the operation amount of the accelerator pedal (hereinafter referred to as "accelerator opening") APO detected by the accelerator sensor 111, the depression amount of the brake pedal (hereinafter referred to as "brake pedal force") BPF detected by the brake sensor 112, the shift position SFT of the automatic transmission detected by the shift position sensor 113, and the wheel speed WSP detected by the wheel speed sensor 115. In addition, it inputs the output information from the first external sensor 114. In the present embodiment, the first external sensor 114 is an external sensor for rear monitoring, and for example, a sonar sensor can be adopted. The wheel speed WSP is the rotational speed of the wheel (in this embodiment, the driven wheel), and is an operating state parameter correlated with the traveling speed of the vehicle, that is, the vehicle speed VSP.

[0019] The engine controller 101 constitutes the "engine torque suppression means" and "engine torque reduction means" according to the present embodiment, and implements the "starting torque suppression control" and "braking torque reduction control" according to the present embodiment.

[0020] The brake controller 201 controls the operation of the brake device. The control target of the brake controller 201 includes the brake actuator 221, and the brake controller 201 reads the automatic brake control information from the AEB controller 301 described later. Then, it performs a predetermined calculation based on the read information, and outputs the actuator operation amount, which is the result of the calculation, to the brake actuator 221. The brake actuator 221 operates according to the actuator operation amount and adjusts the pressure of the brake oil (hereinafter referred to as "brake hydraulic pressure"). The braking force acting on the vehicle increases as the brake hydraulic pressure increases, and decreases as the brake hydraulic pressure decreases. The brake hydraulic pressure is, for example, the pressure of the brake oil in the brake master cylinder.

[0021] The AEB controller 301 provides automatic brake control information to the engine controller 101 and the brake controller 201. The information that the AEB controller 301 provides to the engine controller 101 and the brake controller 201 includes information indicating whether or not there is a possibility of collision with an obstacle ahead. The control performed by the engine controller 101 and the brake controller 201 based on the automatic brake control information from the AEB controller 301 will be described in detail later.

[0022] The AEB controller 301 receives output information from the external sensors 311 and 312, as well as the road surface tilt angle ANG detected by the tilt angle sensor 313, the vehicle acceleration ACC detected by the acceleration sensor 314, and the wheel speed WSP detected by the wheel speed sensor 115. In this embodiment, the external sensors 311 and 312 are external sensors for forward monitoring, and multiple external sensors are employed. For example, a camera can be used as the second external sensor 311, and a millimeter-wave radar can be used as the third external sensor 312. Based on the output information from the second and third external sensors 311 and 312, the AEB controller 301 performs predetermined calculations to detect the presence or absence of obstacles near the front of the vehicle (hereinafter referred to as "forward obstacles") and to determine their attributes. The attributes of an obstacle include, for example, whether it is a person or an object, and objects include other vehicles other than the vehicle itself, such as a preceding vehicle. The AEB controller 301 detects the presence of an obstacle ahead and, if it determines that there is a possibility of collision with that obstacle, outputs automatic brake control information indicating the possibility of collision with the obstacle ahead to the engine controller 101 and the brake controller 201.

[0023] The AEB controller 301 constitutes the "automatic brake control means" according to this embodiment and performs the "automatic brake control" according to this embodiment. Furthermore, the AEB controller 301 cooperates with the second and third external sensors 311 and 312 to constitute the "obstacle detection means" according to this embodiment.

[0024] The wheel speed sensor 115 constitutes the "wheel speed detection means" according to this embodiment, the tilt angle sensor 313 constitutes the "tilt angle detection means" according to this embodiment, and the acceleration sensor 314 constitutes the "acceleration detection means" according to this embodiment.

[0025] The engine controller 101, brake controller 201, and AEB controller 301 are connected to each other in a way that allows them to communicate with one another. For example, various sensor output information such as the tilt angle ANG input to the AEB controller 301 can be shared among the engine controller 101, brake controller 201, and AEB controller 301, for example, via bus communication.

[0026] Figure 2 is a flowchart showing the basic flow of automatic brake control performed by the vehicle control device 1 according to this embodiment. In this embodiment, automatic brake control is performed by the AEB controller 301 at predetermined intervals.

[0027] In S101, various sensor output information related to automatic brake control is read, including output information from the second and third external sensors 311 and 312, the road surface tilt angle ANG detected by the tilt angle sensor 313, and the vehicle acceleration ACC detected by the acceleration sensor 314.

[0028] In step S102, the possibility of collision with an obstacle ahead is detected. In this embodiment, the collision possibility detection process is performed according to the procedure shown in the flowchart of Figure 4.

[0029] In the flowchart of Figure 4, step S301 determines whether or not an obstacle near the front of the vehicle, i.e., a forward obstacle, has been detected. In this embodiment, the detection of the presence of a forward obstacle is based on the output information from external sensors 311 and 312. If the presence of a forward obstacle is detected, i.e., if a forward obstacle exists, the process proceeds to S302. If the presence of a forward obstacle is not detected, the collision possibility detection process is terminated without executing the processes from S302 to S304.

[0030] In S302, the predicted time until collision with an obstacle ahead (hereinafter referred to as "predicted collision time") Tcol is calculated. The calculation of the predicted collision time Tcol is based, for example, on the distance to the obstacle ahead and the vehicle speed VSP. The vehicle's acceleration ACC may also be considered in the calculation of the predicted collision time Tcol.

[0031] In S303, it is determined whether the predicted collision time Tcol is shorter than a predetermined time Tths. If the predicted collision time Tcol is shorter than the predetermined time Tths, the process proceeds to S304; otherwise, the collision possibility detection process ends without executing the process in S304.

[0032] In S304, a potential collision with an obstacle ahead is detected, and a flag is set, for example, to indicate that a collision is possible.

[0033] figure 2 Returning to the flowchart shown, in S103, it is determined whether the collision possibility detection process has detected a possibility of collision with an obstacle ahead. If a possibility of collision is detected, proceed to S104; otherwise, the automatic brake control by this routine is terminated without executing the subsequent processes.

[0034] In S104, the automatic brake or collision mitigation brake is activated. Specifically, the brake controller 201 is instructed to activate the brake actuator 221 to increase the brake fluid pressure. As a result, the brake fluid pressure increases, the brake system activates regardless of the brake pedal operation, and braking force (BRK) is automatically generated in the vehicle.

[0035] In this embodiment, braking torque reduction control is performed in conjunction with the operation of the automatic brake, or in other words, the generation of braking force BRK by automatic brake control, to reduce the engine torque to a predetermined braking limit torque. The braking torque reduction control is performed by the engine controller 101, which has acquired automatic brake control information from the AEB controller 301. After the vehicle has stopped due to the generation of braking force BRK, the engine controller 101 increases the engine torque to a creep-equivalent torque. In other words, in this embodiment, the braking limit torque is smaller than the creep-equivalent torque. Creep-equivalent torque refers to the torque output by the engine when the accelerator is fully closed.

[0036] In S105, the braking force BRK generated by the S104 process is maintained even after the vehicle has braked. For example, the brake fluid pressure is maintained even after the vehicle has come to a stop due to the generation of the braking force BRK, thereby retaining that braking force BRK.

[0037] In S106, it is determined whether the driver has pressed the brake pedal while the braking force BRK is being maintained. If the brake pedal is pressed, the process proceeds to S108; otherwise, it proceeds to S107. In other words, if the driver presses the brake pedal while the braking force BRK is being maintained, the process proceeds to S108 to switch to normal brake control in response to the brake pedal operation.

[0038] In S107, it is determined whether a predetermined time has elapsed since the transition to maintaining braking force (BRK). In simple terms, the elapsed time after stopping due to the generation of braking force (BRK) is measured, and it is determined whether this has reached a predetermined time. If the predetermined time has elapsed, the process proceeds to S108; otherwise, it proceeds to S109. In other words, if braking force (BRK) is maintained for a predetermined time after stopping without any accelerator or brake operation, the process proceeds to S108 to transition to a state where the vehicle can be allowed to restart.

[0039] In S108, the automatic braking system is deactivated. Specifically, the brake controller 221 is instructed to activate the brake actuator 221 to quickly reduce the brake fluid pressure.

[0040] In S109, it is determined whether the driver has pressed the accelerator pedal while the braking force BRK is being maintained. If the accelerator pedal is pressed, the process proceeds to S110; otherwise, the process from S106 to S109 is repeated.

[0041] In the S110, a brake force retention release process is executed. In other words, if the driver presses the accelerator pedal while the brake force BRK is being held, the brake force BRK retention is released by the control force retention release process, allowing the vehicle to restart in accordance with the driver's intention to start or accelerate.

[0042] Figure 3 is a flowchart showing the contents of the brake force retention release process according to this embodiment.

[0043] In S201, it is detected that the driver's pressing of the accelerator pedal (S109 in Figure 2) is an erroneous operation not based on the driver's own will. In this embodiment, the erroneous start detection process is carried out according to the procedure shown in the flowchart of Figure 5.

[0044] In S401, it is determined whether or not an obstacle ahead has been detected. If an obstacle ahead is detected, the process proceeds to S402. If no obstacle is detected, the process from S402 to S404 is skipped, and the false start detection process ends.

[0045] In S402, it is determined whether the vehicle speed VSP is less than or equal to a predetermined vehicle speed VSP1. If the vehicle speed VSP is less than or equal to the predetermined vehicle speed VSP1, the process proceeds to S403. If it is higher than the predetermined vehicle speed VSP, the process for detecting a false start is terminated without executing processes S403 and S404. The predetermined vehicle speed VSP1 is, for example, 10 km / h, and the process in S402 determines whether the vehicle is traveling at a slow speed, such as a crawl, or is stopped.

[0046] In S403, it is determined whether the accelerator pedal opening APO is greater than or equal to a predetermined opening APO1. If the accelerator pedal opening APO is greater than or equal to the predetermined opening APO1, the process proceeds to S404. If it is less than the predetermined opening APO1, the process in S404 is not executed, and the unintended acceleration detection process is terminated. The predetermined opening APO1 is an opening that allows it to be determined that the pressing of the accelerator pedal is an erroneous operation by the driver, such as when the driver hastily and forcefully presses the accelerator pedal.

[0047] In S404, the system detects that the driver's pressing of the accelerator pedal (S109 in Figure 2) is an incorrect operation, and detects that the vehicle has started erroneously. For example, it sets a flag to indicate that erroneous starting has been detected.

[0048] Returning to the flowchart shown in Figure 3, in S202, it is determined whether or not the vehicle has started erroneously through the erroneous start detection process. If an erroneous start is detected, proceed to S207; otherwise, proceed to S203.

[0049] In this embodiment, if the vehicle is detected to have started unexpectedly after coming to a stop due to the generation of braking force BRK, starting torque suppression control is implemented to suppress the increase in engine torque in response to accelerator operation. Starting torque suppression control is performed by the engine controller 101 in cooperation with the automatic brake control by the AEB controller 301. When the starting torque suppression control is performed (hereinafter sometimes referred to as "torque reduction"), the engine controller 101 controls the engine torque to the starting target torque described later for the duration that the starting torque suppression control is continued. Then, when the starting torque suppression control is terminated, the engine controller 101 gradually increases the engine torque from the starting target torque toward a target torque corresponding to the accelerator opening APO.

[0050] In S203, the brake force (BRK) is released. In other words, if the presence of an obstacle ahead disappears while the brake force (BRK) is being held, or if the driver's pressing of the accelerator pedal is not due to driver error but based on the driver's own will, the system proceeds to S203 to allow for a relatively early start. If no unintended start is detected, that is, when torque suppression is not performed (hereinafter sometimes referred to as "when torque reduction is not performed"), the system does not perform torque suppression control at the start, and outputs engine torque according to the accelerator opening (APO).

[0051] In S204, the braking force BRK is gradually reduced. Specifically, the brake controller 201 is instructed to activate the brake actuator 221 to gradually decrease the brake fluid pressure.

[0052] In S205, it is determined whether or not the vehicle has started moving in the direction of travel. If the vehicle has started moving in the direction of travel, the process proceeds to S206; otherwise, the processes of S204 and S205 are repeated. In this embodiment, the recognition of the vehicle starting in the direction of travel is achieved by detecting that the change in acceleration, which is determined based on the wheel speed WSP detected by the wheel speed sensor 115, matches the change in acceleration ACC detected by the acceleration sensor 314.

[0053] In S206, the braking force BRK is rapidly reduced. Specifically, the brake controller 201 is instructed to activate the brake actuator 221 to rapidly reduce the brake fluid pressure; in other words, the gradient at which the braking force BRK is reduced is increased compared to the gradient at which it is reduced by the process in S204 described above.

[0054] In S207, after the vehicle has stopped due to the generation of braking force BRK, it is determined whether the operation of the tilt angle sensor 313 has stabilized and whether the detection of the tilt angle ANG by the tilt angle sensor 313 has been completed. If the detection of the tilt angle ANG is completed, the process proceeds to S208; otherwise, the processes of S202 and S207 are repeated.

[0055] Whether or not the detection of the tilt angle ANG is complete is determined by comparing the elapsed time ΔT after stopping due to the generation of braking force BRK with a predetermined sensor stabilization time ΔTstb. The sensor stabilization time ΔTstb is the time required for the operation of the tilt angle sensor 313 to stabilize after stopping, and changes according to the vehicle's deceleration DCL during braking.

[0056] Figure 6 is a graph showing the relationship between the sensor stabilization time ΔTstb and the deceleration DCL (specifically, its absolute value |DCL|). In this embodiment, the sensor stabilization time ΔTstb is set to be shorter as the absolute value of the deceleration |DCL| decreases.

[0057] In S208, it is determined whether the actual engine torque has reached the slip-down suppression torque. If it has reached the slip-down suppression torque, the process proceeds to S209; otherwise, the process in S209 is repeated until it has reached the torque.

[0058] Here, the engine controller 101 sets an engine torque (hereinafter referred to as "slip suppression torque") that can suppress the vehicle's backward sliding in the direction opposite to the direction of travel, without relying on the braking force generated by the foot brake, based on the road surface tilt angle ANG detected by the tilt angle sensor 313 after the sensor stabilization time ΔTstb has elapsed. For example, the slip suppression torque when climbing a slope is an engine torque that can suppress the vehicle's backward sliding. The engine controller 101 then controls the engine torque to match the slip suppression torque. The slip suppression torque corresponds to the "starting target torque" in this embodiment.

[0059] In S209, the holding of the braking force BRK is released. In other words, when torque reduction is performed to suppress torque during restart when the vehicle is restarted, the increase in engine torque in response to accelerator operation is suppressed. However, if the engine torque has reached the target torque for preventing the vehicle from sliding backward, the holding of the braking force BRK by the automatic brake control is released, and even if the braking force BRK is reduced, the engine torque can still suppress the vehicle from sliding backward. Furthermore, by the time the torque reduction control during restart is completed and the engine torque is gradually increased, the braking force BRK has already been reduced by the process in S210 described below, making it possible to start the vehicle smoothly.

[0060] In S210, the braking force BRK is rapidly reduced. Specifically, the brake controller 201 is instructed to activate the brake actuator 221 to rapidly reduce the brake fluid pressure. In this embodiment, the gradient at which the braking force BRK is reduced by the process in S209 is greater than the gradient at which it is reduced by the process in S204, and is approximately equal to the gradient at which it is reduced by the process in S206 after recognizing the vehicle's movement in the direction of travel.

[0061] Figure 7 is a time chart showing the operation of the vehicle control device 1 according to this embodiment.

[0062] Assume a situation where a vehicle is traveling uphill at a vehicle speed of VSP1 with engine torque TRQ3 output, and a preceding vehicle, which is an obstacle, appears in front of it. After detecting the presence of the preceding vehicle, the vehicle continues to travel at vehicle speed VSP1, and at time t1, if it is determined that the predicted collision time Tcol with the preceding vehicle has become shorter than a predetermined time Tths, the AEB controller 301 detects the possibility of a collision with the preceding vehicle and performs automatic braking control. By performing automatic braking control, brake The hydraulic pressure is increased to the peak hydraulic pressure and then maintained at the maximum holding hydraulic pressure. brakeDue to fluctuations in hydraulic pressure, the brake system generates a braking force BRK2 equivalent to the peak hydraulic pressure, and then maintains a braking force BRK1 equivalent to the maximum holding hydraulic pressure. In conjunction with the generation of the braking force BRK, the engine controller 101 performs braking torque reduction control, reducing the engine torque to the braking limit torque TRQ0. Due to the generation of the braking force BKR and the reduction of the engine torque TRQ, the vehicle decelerates and comes to a stop at time t2.

[0063] After the vehicle comes to a stop, the engine controller 101 increases the engine torque from the braking limit torque TRQ0 to the creep equivalent torque TRQ1, and maintains the creep equivalent torque TRQ1 while the braking force BRK is held.

[0064] Then, at time t3 after the vehicle has stopped, the driver will release their foot from the accelerator pedal, and the accelerator pedal will be returned to the fully closed position.

[0065] At time t4, when the driver presses the accelerator pedal, the engine torque TRQ is increased and the braking force BRK is released. However, the control after the accelerator operation differs depending on whether the preceding vehicle remains close ahead or whether the preceding vehicle moves forward and leaves the area targeted by the obstacle ahead.

[0066] If a preceding vehicle remains close ahead, and the driver's accelerator operation is large enough to deviate from the normal operating range, starting torque suppression control is implemented (torque reduction implemented) to suppress the increase in engine torque in response to accelerator operation. Conversely, if the preceding vehicle deviates from the range targeted by the obstacle ahead, starting torque suppression control is not implemented (torque reduction not implemented), and engine torque corresponding to the accelerator opening APO is output. Figure 7 shows the engine torque TRQ, braking force BRK, and vehicle speed VSP after accelerator operation, with dotted lines for when torque reduction is implemented and solid lines for when torque reduction is not implemented.

[0067] When torque reduction is performed, the engine torque TRQ (creep-equivalent torque TRQ1) is maintained even after accelerator operation, and the braking force BRK1 equivalent to the maximum hydraulic pressure is held. Then, when the elapsed sensor stabilization time ΔTstb is determined at time t6, the tilt angle sensor 313 detects the road surface tilt angle ANG, calculates the starting target torque TRQ2 (in this embodiment, the slip suppression torque) according to the tilt angle ANG, and controls the engine torque TRQ to the starting target torque TRQ2. When the engine torque TRQ reaches the starting target torque TRQ2 (time t7), the AEB controller 301 releases the holding of the braking force BRK and quickly reduces the braking force BRK.

[0068] When torque reduction is not performed, the engine torque TRQ is controlled toward a target torque corresponding to the accelerator opening APO, and the braking force BRK is released, gradually reducing the braking force BRK. When the increase in engine torque TRQ and the reduction in braking force BRK confirm that the vehicle is moving in the direction of travel at time t5, the AEB controller 301 rapidly reduces the braking force BRK with a larger gradient.

[0069] The vehicle control device according to this embodiment has the above configuration. The effects obtained by this embodiment will be described below.

[0070] Firstly, the system detects the presence of an obstacle in the vehicle's direction of travel (forward obstacle), and if there is a possibility of collision with that obstacle, it automatically applies braking force (BRK) to the vehicle and maintains that braking force (BRK) for a predetermined period of time. This reduces the possibility of collision with an obstacle, and even if a collision does occur, it helps to mitigate the damage caused by the collision.

[0071] Here, after generating braking force BRK through automatic brake control, the braking force BRK is released in response to the driver's accelerator input, allowing the vehicle to restart or accelerate again. However, the timing of releasing the braking force BRK differs depending on whether torque suppression control is implemented (torque reduction implemented) or not (torque reduction not implemented).

[0072] Specifically, when torque reduction is performed, the timing of releasing the brake force BRK is delayed compared to when torque reduction is not performed. In other words, the period from accelerator operation (time t4 shown in Figure 7) to the release of the brake force BRK is set to be longer when torque reduction is performed than when torque reduction is not performed. In this embodiment, when torque reduction is performed, the accelerator operation and the release of the brake force BRK are synchronized, and when torque reduction is not performed, after accelerator operation, the brake force BRK is released after waiting for the formation of the starting target torque (slip suppression torque) TRQ2.

[0073] This allows the braking force (BRK) to be released relatively early (at time t4) when torque reduction is not performed, enabling the vehicle to restart or accelerate quickly.

[0074] On the other hand, when torque reduction is implemented, the timing of releasing the braking force BRK is delayed, and the braking force BRK is continued to be held even after accelerator operation, and the release is made after the formation of the slip-down suppression torque TRQ2 (time t7), thereby mitigating the adverse effects associated with the implementation of starting torque suppression control.

[0075] For example, if the system detects an obstacle ahead while climbing a slope and stops using automatic braking control, the system can prevent a sudden press of the accelerator pedal after stopping by suppressing the increase in engine torque TRQ through starting torque suppression control. This prevents the braking force BRK from being released even though sufficient engine torque TRQ has not been generated, thus avoiding a situation where the vehicle rolls backward.

[0076] Thus, according to this embodiment, it is possible to make the vehicle's behavior after braking by automatic brake control, when the accelerator is pressed, safer and more in line with the driver's intentions.

[0077] Secondly, by implementing braking torque reduction control in synchronization with the implementation of automatic brake control, and reducing the engine torque TRQ to a predetermined braking limit torque TRQ0, it becomes possible to make the braking by automatic brake control work more effectively.

[0078] Thirdly, by setting the engine torque generated by the starting torque suppression control, that is, the roll-down suppression torque TRQ2, to be greater than the braking limit torque TRQ0, it becomes possible to generate sufficient engine torque to suppress the vehicle rolling backward when stopping on an uphill road, thereby achieving safer behavior.

[0079] Furthermore, the third effect described above can be obtained not only when stopping on an uphill slope, but also when stopping on a downhill slope. For example, the roll suppression torque TRQ2 can be set to an engine torque sufficient to suppress the vehicle from rolling forward when stopping on a downhill slope. Whether the road being driven on is an uphill or downhill slope can be determined based on the slope angle ANG, and whether the direction of the roll is forward or backward can be determined based on the shift position SFT.

[0080] Fourthly, when the vehicle is on an incline, the downward sliding suppression torque TRQ2 is set based on the road surface inclination angle ANG, making it possible to suppress the downward sliding of the vehicle even on an incline, regardless of the braking force.

[0081] Furthermore, when torque reduction is implemented, after the driver operates the accelerator, the braking force BRK is maintained until the engine torque TRQ reaches the slip-down suppression torque TRQ2. This makes it possible to avoid a situation where the vehicle slips due to insufficient engine torque TRQ after the braking force BRK is released.

[0082] Furthermore, the tilt angle sensor 313 used to detect the tilt angle ANG is affected by the deceleration during vehicle braking, making it difficult to accurately detect the tilt angle ANG until its operation stabilizes.

[0083] Therefore, fifthly, by detecting the road surface inclination angle ANG earlier after accelerator operation, especially when the absolute value of the deceleration DCL is small, and setting the roll suppression torque TRQ2, when the absolute value of the deceleration DCL is large, it is possible to avoid a situation where the detection of the inclination angle ANG and the setting of the roll suppression torque TRQ2 are excessively affected by deceleration during braking, and to set an appropriate roll suppression torque TRQ2 based on the accurate inclination angle ANG.

[0084] On the other hand, when the absolute value of the deceleration DCL is small, it becomes possible to release the braking force BRK relatively soon after accelerator operation. This makes it possible to avoid a situation where the return of engine torque TRQ and the reduction of braking force BRK interfere with each other after the starting torque suppression control is completed, thereby impairing the vehicle's ability to start smoothly.

[0085] Sixth, when torque reduction is not performed, the braking force BRK is released in conjunction with the driver's accelerator operation, and the braking force BRK is gradually reduced. This prevents situations where excessive pressing of the accelerator pedal causes the vehicle to start or accelerate abruptly, thereby achieving safer behavior.

[0086] Here, while the braking force BRK is being maintained, the engine torque TRQ is increased from the braking limit torque TRQ0 to the creep-equivalent torque TRQ1. This allows the vehicle to start quickly after the braking force BRK is released, making the vehicle's behavior more in line with the driver's intentions.

[0087] Seventh, by confirming that the vehicle is moving in the direction of travel, it is possible to confirm that the driver intends to start or accelerate and that the vehicle is not sliding backward against the driver's will on an inclined road surface. In such cases, by increasing the gradient when reducing the braking force (BRK) and rapidly reducing the braking force (BRK), it becomes possible to achieve more appropriate behavior that reflects the driver's intentions. [Explanation of symbols]

[0088] 1...Vehicle control device, 101...Engine controller, 201...Brake controller, 301...Automatic emergency braking (AEB) controller, 111...Accelerator sensor, 112...Brake sensor, 113...Shift position sensor, 114...First external sensor (sonar sensor), 115...Wheel speed sensor, 311...Camera, 312...Millimeter-wave radar, 313...Tilt angle sensor, 314...Accelerometer, 121...Fuel injector, 221...Brake actuator.

Claims

1. An obstacle detection means for detecting the presence of an obstacle in the direction of travel of the vehicle, Automatic brake control means that determines whether there is a possibility of collision with the aforementioned obstacle, and if there is a possibility of collision, automatically generates braking force for the vehicle and then performs automatic brake control that maintains the braking force until a predetermined time, After the generation of the braking force, if the obstacle continues to exist, the system includes an engine torque suppression means that implements starting torque suppression control to suppress the increase in engine torque in response to the driver's accelerator operation at a predetermined vehicle speed and above a predetermined accelerator opening, The aforementioned automatic brake control means is After the braking force is generated, if the driver operates the accelerator, the holding of the braking force is released. A vehicle control device that sets the timing for releasing the holding of the braking force after the aforementioned accelerator operation to a later time during torque suppression when the torque suppression control at the start is implemented, compared to other times when torque suppression is not implemented.

2. The vehicle control device according to claim 1, further comprising engine torque reduction means for performing braking torque reduction control, which reduces the engine torque to a predetermined braking limit torque regardless of the accelerator opening, in synchronization with the implementation of the automatic brake control.

3. The vehicle control device according to claim 2, wherein the engine torque generated by the engine torque suppression means by the starting torque suppression control is greater than the braking limiting torque.

4. The system further includes a tilt angle detection means for detecting the tilt angle of the road surface, The engine torque suppression means sets a target starting torque, which is the engine torque to be generated by the starting torque suppression control, based on the road surface inclination angle detected by the inclination angle detection means. The vehicle control device according to claim 3, wherein the automatic brake control means releases the holding of the braking force after the actual engine torque reaches the target torque for starting, following the accelerator operation by the driver, when torque suppression is performed.

5. The tilt angle detection means detects the tilt angle of the road surface after a predetermined time has elapsed following the driver's accelerator operation. The engine torque suppression means sets the target torque at startup based on the road surface inclination angle detected by the inclination angle detection means after the predetermined time has elapsed. The vehicle control device according to claim 4, wherein the predetermined time is shorter when the absolute value of the degree of deceleration of the vehicle due to the braking force is small.

6. The engine torque reduction means increases the engine torque from the braking limit torque to the creep equivalent torque while the braking force is maintained. The vehicle control device according to claim 2, wherein the automatic brake control means releases the holding of the braking force in conjunction with the driver's accelerator operation when torque suppression is not performed, and gradually reduces the braking force.

7. A wheel speed detection means for detecting wheel speed, The system further comprises acceleration detection means for detecting the acceleration of a vehicle, The vehicle control device according to claim 6, wherein the automatic brake control means increases the gradient used to reduce the braking force when the change in acceleration determined based on the wheel speed detected by the wheel speed detection means matches the change in the vehicle's acceleration detected by the acceleration detection means.

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