JP7826151B2 - Evacuation driving control device - Google Patents

Description

This disclosure relates to an evacuation driving control device.

Conventionally, hybrid vehicles have been known that are equipped with two power sources, an internal combustion engine and a motor generator, and rely on intake pressure from the internal combustion engine for brake booster vacuum. In hybrid vehicles, if an abnormality occurs in the internal combustion engine, the vehicle performs evacuation running, driving the motor generator using only power from the power storage device. Furthermore, from the perspective of safe driving performance, the vehicle speed limit is typically set to an extremely low speed during evacuation running (see, for example, Patent Document 1 and Patent Document 2).

JP 2017-65283 A JP 2016-160781 A

By limiting the vehicle speed limit to an extremely low speed during evacuation maneuvers, the driver can stop the vehicle by pressing the brake pedal, even if the brake booster's negative pressure is not maintained due to an internal combustion engine malfunction. However, if the vehicle is traveling on a main road or other road and an evacuation maneuver is performed with the vehicle speed limit limited to an extremely low speed due to an internal combustion engine malfunction, dangerous situations may arise depending on the driving conditions. However, simply increasing the vehicle speed limit during evacuation maneuvers can result in dangerous situations due to longer braking distances if the brake booster's negative pressure cannot be maintained. For this reason, conventional technology has sometimes made it difficult to improve driving performance during evacuation maneuvers.

The problem that this disclosure aims to solve is to provide an evacuation driving control device that can improve driving performance during evacuation driving.

The escape travel control device disclosed herein is installed in a vehicle equipped with a traction motor-generator that supplies driving force to drive wheels and generates electricity through regenerative braking, an internal combustion engine, a motoring motor-generator driven by the internal combustion engine to generate electricity, an electric storage device that is charged and discharged by the traction motor-generator and the motoring motor-generator, and a brake booster that amplifies brake pedal force using the intake vacuum of the internal combustion engine. The escape travel control device includes a negative pressure ensuring control that executes negative pressure ensuring control to ensure a first negative pressure greater than zero in the brake booster when drive of the internal combustion engine stops due to an abnormality in the internal combustion engine, a first determination unit that determines whether the first negative pressure has been ensured in the brake booster by the negative pressure ensuring control, and an escape travel control unit that, if it determines that the first negative pressure has been ensured, sets a second speed higher than a first speed, which is a predetermined vehicle speed limit value for escape travel speed, as the vehicle speed limit value and controls the vehicle to perform escape travel.

The evacuation driving control device disclosed herein can improve driving performance during evacuation driving.

FIG. 1 is a diagram showing a schematic configuration of a vehicle according to an embodiment. FIG. 2 is a diagram illustrating a hardware configuration of an example of a vehicle control device. FIG. 3 is a block diagram of an example of the functional configuration of the emergency travel control device. FIG. 4 is a flowchart showing an example of the flow of information processing.

An embodiment of an emergency driving control device according to the present disclosure will be described below with reference to the accompanying drawings.

Figure 1 is a diagram showing the general configuration of a vehicle 1 according to this embodiment. Vehicle 1 is an example of a hybrid vehicle.

The vehicle 1 includes a vehicle control device 10, an internal combustion engine 12, a motoring motor-generator 14, a traction motor-generator 16, an electric storage device 18, a brake booster 11, and an electric parking brake 23.

The internal combustion engine 12 is an engine. The internal combustion engine 12 is, for example, a four-stroke engine having multiple cylinders.

The motoring motor generator 14 is driven by the internal combustion engine 12 to generate electricity. The crankshaft, which is the rotating shaft of the internal combustion engine 12, is mechanically connected to the rotating shaft of the motoring motor generator 14 via a gear mechanism. The rotational driving force output by the internal combustion engine 12 is input to the motoring motor generator 14, causing the motoring motor generator 14 to generate electricity. The electricity generated by the motoring motor generator 14 is charged into the power storage device 18 and supplied to the traction motor generator 16.

The motor-generator 14 for motoring also functions as an electric motor that generates a rotational driving force to rotate the crankshaft of the internal combustion engine 12. In particular, the motor-generator 14 for motoring is capable of supplying a driving force to the internal combustion engine 12 to perform motoring, which forcibly rotates the internal combustion engine 12.

The traction motor generator 16 supplies driving force to the drive wheels 22 and generates electricity through regenerative braking. Specifically, the traction motor generator 16 generates driving force for the vehicle 1 to travel using power supplied from the motoring motor generator 14 and the power storage device 18, and supplies the driving force to the drive wheels 22 via the reduction gear 20. The traction motor generator 16 also generates electricity by rotating in conjunction with the drive wheels 22, recovering the kinetic energy of the vehicle 1 as electrical energy. The power generated through this regenerative braking is charged into the power storage device 18.

The power storage device 18 is charged and discharged by the motoring motor generator 14 and the traction motor generator 16. The power storage device 18 charges and stores the electricity generated by each of the motoring motor generator 14 and the traction motor generator 16. The power storage device 18 also discharges the electricity required to operate each of the motoring motor generator 14 and the traction motor generator 16 as electric motors, and supplies the necessary electricity to each of the motoring motor generator 14 and the traction motor generator 16. The power storage device 18 is, for example, a battery or a capacitor.

Inverter 24 and inverter 26 function as part of the PCU (Power Control Unit).

The inverter 24 converts the AC power generated by the motoring motor generator 14 into DC power and outputs it to at least one of the power storage device 18 and the inverter 26. Furthermore, when the motoring motor generator 14 is operated as an electric motor, the inverter 24 converts the DC power supplied from at least one of the power storage device 18 and the inverter 26 into AC power and outputs it to the motoring motor generator 14.

The inverter 26 converts DC power supplied from at least one of the power storage device 18 and the inverter 24 into AC power and outputs it to the traction motor generator 16. The inverter 26 also converts AC power generated by the traction motor generator 16 through regenerative braking into DC power and outputs it to at least one of the power storage device 18 and the inverter 24.

The brake booster 11 amplifies the force applied to the brake pedal 13 by utilizing the intake vacuum of the internal combustion engine 12. The brake booster 11 may be a known vacuum-type brake booster that utilizes the intake vacuum of the internal combustion engine 12. Negative pressure is stored in the brake booster 11 by the intake vacuum of the internal combustion engine 12, and the force applied to the brake pedal 13 by the driver is amplified by the action of the vacuum stored in the brake booster 11.

In this embodiment, the brake booster 11 may be provided with a vacuum pump 15. The vacuum pump 15 is an electrically driven pump that supplies vacuum to the brake booster 11 in situations such as when the intake vacuum of the internal combustion engine 12 cannot be used. Note that the vehicle 1 is not limited to a configuration equipped with a vacuum pump 15.

The electric parking brake 23 is a system that controls the parking brake provided on the vehicle 1 by operating an electric motor. The driving force of the electric motor is transmitted to the parking brake shoes via a gear mechanism, cables, etc. The brake shoes are pressed against the brake drums provided on the drive wheels 22, and braking force is generated by the frictional force.

The vehicle 1 is also equipped with various sensors, such as a negative pressure sensor 17, a brake stroke sensor 19, and a vehicle speed sensor 21.

The negative pressure sensor 17 detects the level of negative pressure stored in the brake booster 11. The brake stroke sensor 19 detects the brake stroke. The brake stroke is the amount of operation of the brake pedal 13, which is used to adjust the braking force applied by the brake mechanism. The vehicle speed sensor 21B detects the speed of the vehicle 1.

The vehicle control device 10 is a controller that controls the vehicle 1.

The vehicle control device 10 acquires detection results from various sensors mounted on the vehicle 1. For example, the vehicle control device 10 acquires the level of negative pressure stored in the brake booster 11, the brake stroke, the vehicle speed of the vehicle 1, the ambient temperature of the power storage device 18, the charge/discharge current to/from the power storage device 18, the remaining capacity of the power storage device 18, the accelerator opening, the shift position, the ON/OFF status of the switch, the gradient of the road surface, the power generated by the motoring motor generator 14, and the power generated by the traction motor generator 16. Based on these detection results, the vehicle control device 10 controls the rotational driving force of the traction motor generator 16, the rotational driving force of the internal combustion engine 12, and the magnitude of the power generated by the motoring motor generator 14.

The vehicle control device 10 includes, for example, an HEV_ECU (Electronic Control Unit) 30, an engine ECU 32, a generator ECU 34, a battery ECU 36, and a drive unit ECU 38.

The HEV_ECU 30, engine ECU 32, generator ECU 34, battery ECU 36, and drive unit ECU 38 are interconnected so that they can communicate with each other via electrical communication lines such as a CAN (Controller Area Network).

The HEV_ECU 30 includes an emergency driving control device 40. The HEV_ECU 30 and the emergency driving control device 40 will be described later. The engine ECU 32 is an engine controller that controls the internal combustion engine 12. The generator ECU 34 is a controller that controls the motor-generator 14 for motoring and the inverter 24. The battery ECU 36 is a controller that controls the power storage device 18. The drive machine ECU 38 is a controller that controls the driving motor-generator 16 and the inverter 26.

Figure 2 is a hardware configuration diagram of an example of a vehicle control device 10.

The HEV_ECU 30, emergency driving control device 40, engine ECU 32, generator ECU 34, battery ECU 36, drive unit ECU 38, and emergency driving control device 40 provided in the vehicle control device 10 are a hardware configuration utilizing a conventional computer, with a CPU (Central Processing Unit) 11A, ROM (Read Only Memory) 11B, RAM (Random Access Memory) 11C, and I/F 11D interconnected by a bus 11E.

CPU 11A is a computing device that controls the vehicle control device 10 of this embodiment. ROM 11B stores programs that realize various processes performed by CPU 11A. RAM 11C stores data necessary for various processes performed by CPU 11A. I/F 11D is an interface for sending and receiving data.

The program for executing information processing executed by the vehicle control device 10 of this embodiment is provided by being pre-installed in ROM 11B or the like. The program executed by the vehicle control device 10 of this embodiment may also be provided by being recorded on a computer-readable recording medium such as a CD-ROM, flexible disk (FD), CD-R, or DVD (Digital Versatile Disk) in a format that can be installed or executed on the vehicle control device 10.

Returning to Figure 1, the explanation continues. The HEV_ECU 30 manages and controls the engine ECU 32, generator ECU 34, battery ECU 36, drive unit ECU 38, and other components. The HEV_ECU 30 optimally distributes the output of the internal combustion engine 12, the motoring motor-generator 14, and the traction motor-generator 16 according to the vehicle load, driving conditions, and other factors, and controls the entire hybrid system of the vehicle 1 so that the vehicle 1 can run most efficiently.

In this embodiment, the HEV_ECU 30 has an evacuation driving control device 40. The evacuation driving control device 40 is an ECU that performs control for evacuation driving.

Evacuation driving refers to driving the vehicle by stopping the internal combustion engine 12 and driving the traction motor-generator 16 using only power from the power storage device 18.

Figure 3 is a block diagram showing an example of the functional configuration of the evacuation driving control device 40. Figure 4 is a flowchart showing an example of the flow of information processing executed by the evacuation driving control device 40 of this embodiment.

The evacuation travel control device 40 includes an abnormality detection unit 40A, an internal combustion engine stop detection unit 40B, a negative pressure assurance control unit 40C, a first judgment unit 40D, an evacuation travel control unit 40E, a second judgment unit 40F, and a deceleration control unit 40G.

The abnormality detection unit 40A, internal combustion engine stop detection unit 40B, negative pressure control unit 40C, first determination unit 40D, evacuation travel control unit 40E, second determination unit 40F, and deceleration control unit 40G may be implemented by software, i.e., by having a processing device such as CPU 11A execute a program. Furthermore, the charge/discharge control unit 30A may be implemented by hardware such as an integrated circuit (IC). Furthermore, each of these units may be implemented using a combination of software and hardware.

The abnormality detection unit 40A detects an abnormality in the internal combustion engine 12 (step S100). An abnormality in the internal combustion engine 12 refers to a situation in which it is difficult to use the intake negative pressure of the internal combustion engine 12 as negative pressure for the brake booster 11. For example, an abnormality in the internal combustion engine 12 is a state in which the internal combustion engine 12 is unable to perform combustion due to a failure in the drive system, such as a valve, that contributes to the drive of the internal combustion engine 12. For example, the abnormality detection unit 40A detects an abnormality in the internal combustion engine 12 when it receives an abnormality signal indicating an abnormality in the internal combustion engine 12 from the engine ECU 32. Note that the abnormality detection unit 40A may also detect an abnormality in the internal combustion engine 12 based on a signal received from a sensor that detects an abnormality in the internal combustion engine 12.

The internal combustion engine stop detection unit 40B detects the stop of the internal combustion engine 12 due to the occurrence of an abnormality in the internal combustion engine 12 (step S102). For example, the internal combustion engine stop detection unit 40B detects the stop of the internal combustion engine 12 due to the occurrence of an abnormality when, after the abnormality detection unit 40A detects an abnormality in the internal combustion engine 12, it receives a stop signal from the engine ECU 32 indicating the stop of the internal combustion engine 12. Note that if the internal combustion engine 12 is in a driving state or is drivable when the abnormality detection unit 40A detects an abnormality in the internal combustion engine 12, the internal combustion engine stop detection unit 40B may perform stop control to stop the internal combustion engine 12. In this case, when the abnormality detection unit 40A detects an abnormality in the internal combustion engine 12, the internal combustion engine stop detection unit 40B may control the engine ECU 32 to stop driving the internal combustion engine 12.

When the internal combustion engine 12 stops operating due to an abnormality in the internal combustion engine 12, the negative pressure assurance control unit 40C executes negative pressure assurance control so that the brake booster 11 maintains a first negative pressure greater than 0 (step S104).

The first negative pressure is the negative pressure accumulated in the brake booster 11, and is a negative pressure at a level greater than 0. In more detail, the first negative pressure is a level at which the brake booster 11, with the first negative pressure accumulated, amplifies the force applied to the brake pedal 13 and applies it to the brake mechanism of the vehicle 1, thereby enabling the vehicle 1, traveling at a second speed described below, to stop within a predetermined braking distance. The first negative pressure may be set in advance to a level that satisfies these conditions.

The first negative pressure is not limited to a single level of negative pressure, but may be a value representing a range of negative pressure levels with a predetermined width. Even in the case of a range of negative pressure levels with a predetermined width, the first negative pressure may be a negative pressure within a range of levels that does not include 0 (i.e., no negative pressure).

The negative pressure assurance control unit 40C performs negative pressure assurance control so that the brake booster 11 ensures the first negative pressure by controlling at least one of the motoring control of the motor generator 14 for motoring and the control of the negative pressure pump 15.

As described above, the motoring motor-generator 14 is capable of supplying driving force to the internal combustion engine 12 and motoring the internal combustion engine 12 to forcibly rotate it. The negative pressure ensuring control unit 40C controls the motoring motor-generator 14 via the generator ECU 34 to motor the internal combustion engine 12, which has been stopped due to an abnormality. When the internal combustion engine 12 is motored, negative pressure accumulates in the brake booster 11 due to the intake negative pressure of the internal combustion engine 12, and a first negative pressure is ensured in the brake booster 11.

The negative pressure assurance control unit 40C may also execute negative pressure assurance control to ensure a first negative pressure in the brake booster 11 by controlling the negative pressure pump 15.

The negative pressure control unit 40C may execute both the motoring control of the motor-generator 14 for motoring and the control of the vacuum pump 15 as vacuum pressure control. The negative pressure control unit 40C may also determine whether motoring is possible, and if motoring is possible, execute the motoring control of the motor-generator 14 for motoring as vacuum pressure control. If motoring of the internal combustion engine 12 is not possible, the negative pressure control unit 40C may execute the control of the vacuum pump 15 as vacuum pressure control.

The first determination unit 40D determines whether the first negative pressure is maintained in the brake booster 11 (step S106). The first determination unit 40D determines whether the first negative pressure is maintained by determining whether the detection result from the negative pressure sensor 17 indicates a pressure equal to or greater than the first negative pressure.

If the evacuation driving control unit 40E determines that the first negative pressure has been secured in the brake booster 11 (step S106: Yes), it sets a second speed, which is faster than the first speed, as the vehicle speed limit value for the evacuation driving speed (step S108) and controls the vehicle to perform evacuation driving (step S110).

The first speed is a speed that is predetermined as the vehicle speed limit value for the evacuation driving speed. The evacuation driving speed is the vehicle speed of the vehicle 1 during evacuation driving. The first speed is a speed at which the vehicle 1 can be stopped within a predetermined braking distance by the driver's depression force on the brake pedal 13, even when negative pressure is not secured in the brake booster 11, i.e., when the negative pressure in the brake booster 11 is 0 (zero). Specifically, the first speed is, for example, the speed at which the vehicle 1 creeps forward or backward without the accelerator pedal being depressed. The first speed is not limited to a single value, but may be a speed that represents a speed range with a predetermined width.

The second speed is a speed faster than the first speed. More specifically, the second speed is a speed faster than the first speed and at which the driver's brake pedal 13 force can bring the vehicle 1 to a stop in a predetermined braking distance when the first negative pressure is maintained in the brake booster 11. The second speed is not limited to a single value, but may be a speed representing a speed range with a predetermined width. Note that when the speed range has a predetermined width, the first speed and the second speed are non-overlapping speed ranges, and the second speed is faster than the first speed.

The second speed may be predetermined to satisfy the above conditions. Then, when the evacuation travel control unit 40E determines that the first negative pressure has been secured in the brake booster 11, it may set the predetermined second speed as the vehicle speed limit value for the evacuation travel speed.

The evacuation travel control unit 40E may also calculate a second speed corresponding to the level of the first negative pressure ensured in the brake booster 11 by the negative pressure assurance control unit 40C and set this as the vehicle speed limit for the evacuation travel speed. Specifically, the negative pressure assurance control unit 40C acquires the level of the first negative pressure ensured in the brake booster 11 by the negative pressure assurance control unit 40C from the negative pressure sensor 17. Then, if that level of first negative pressure is ensured, the negative pressure assurance control unit 40C calculates as the second speed a speed at which the driver's depression force on the brake pedal 13 can bring the vehicle 1 to a stop within a predetermined braking distance. In other words, the negative pressure assurance control unit 40C calculates a second speed that satisfies the condition according to the level of the ensured first negative pressure, and the higher the level of the ensured first negative pressure, the faster the calculated second speed. The evacuation travel control unit 40E may then set the calculated second speed as the vehicle speed limit for the evacuation travel speed.

The evacuation travel control unit 40E sets the second speed as the vehicle speed limit for the evacuation travel speed and executes evacuation travel control to control the traction motor-generator 16 to perform evacuation travel. In particular, the evacuation travel control unit 40E controls the traction motor-generator 16 via the drive machine ECU 38 to drive the traction motor-generator 16 using only power from the power storage device 18, and to travel at the second speed set as the vehicle speed limit.

In other words, when the negative pressure ensuring control unit 40C ensures the first negative pressure in the brake booster 11, the evacuation travel control unit 40E executes evacuation travel control, which controls the travel motor generator 16 to perform evacuation travel with a second speed, which is faster than the first speed, as the vehicle speed limit value.

Next, the negative pressure assurance control unit 40C determines whether to continue negative pressure assurance control (step S112).

For example, if the brake pedal 13B is operated while the vehicle 1 is traveling, the vacuum pressure control unit 40C determines to continue vacuum pressure control. Specifically, the vacuum pressure control unit 40C determines to continue vacuum pressure control if the vehicle speed detected by the vehicle speed sensor 21 exceeds 0 and the brake stroke sensor 19 detects a brake stroke indicating depression of the brake pedal 13. The vacuum pressure control unit 40C may also determine to continue vacuum pressure control if the vehicle speed detected by the vehicle speed sensor 21 exceeds 0, the vacuum pressure in the brake booster 11 is less than the first vacuum, and the brake stroke sensor 19 detects a brake stroke indicating depression of the brake pedal 13. The vacuum pressure control unit 40C may also determine to continue vacuum pressure control if the vehicle speed sensor 21 detects a vehicle speed exceeding a second vehicle speed.

If the negative pressure control unit 40C determines that negative pressure control should be continued (step S112: Yes), the process returns to step S104. If the negative pressure control unit 40C determines that negative pressure control should not be continued (step S112: No), the routine ends.

On the other hand, if the first judgment unit 40D determines that the first negative pressure is not maintained in the brake booster 11 (step S106: No), the second judgment unit 40F determines whether the vehicle 1 can be decelerated by deceleration control (step S114).

In detail, the second determination unit 40F determines whether the vehicle 1 can be decelerated by deceleration control of a deceleration control mechanism other than the brake booster 11 provided in the vehicle 1. In this embodiment, the second determination unit 40F will be described using an example in which the electric parking brake 23 is used as the deceleration control mechanism other than the brake booster 11.

For this reason, in this embodiment, the second determination unit 40F determines whether the vehicle 1 can be decelerated by deceleration control of the electric parking brake 23 by determining whether the electric motor of the electric parking brake 23 is operating normally.

If the evacuation travel control unit 40E determines that deceleration is possible through deceleration control, which is drive control of the electric parking brake 23 (step S114: Yes), it sets the second speed as the vehicle speed limit value (step S116). The second speed is the same as described above.

Then, if the deceleration control unit 40G determines that the vehicle 1 can be decelerated by deceleration control, it starts deceleration control (step S118). Deceleration control refers to drive control of the electric motor of the electric parking brake 23 based on the detection results of the brake stroke sensor 19 and the vehicle speed sensor 21.

The deceleration control unit 40G drives and controls the electric motor of the electric parking brake 23 in accordance with the detected brake stroke so that a braking force corresponding to the brake stroke detected by the brake stroke sensor 19 is achieved. The deceleration control unit 40G also drives and controls the electric motor of the electric parking brake 23 in accordance with the detected vehicle speed so that the vehicle speed of the vehicle 1 detected by the vehicle speed sensor 21 is maintained at or below a second speed set as a vehicle speed limit value. If the deceleration control unit 40G determines that deceleration is possible through deceleration control, it starts these deceleration controls.

Then, the evacuation travel control unit 40E executes evacuation travel control, controlling the traction motor-generator 16 to perform evacuation travel using the second speed as the vehicle speed limit for the evacuation travel speed (step S120). Specifically, the evacuation travel control unit 40E controls the traction motor-generator 16 via the drive machine ECU 38 to drive the traction motor-generator 16 using only power from the power storage device 18, and to travel at the second speed set as the vehicle speed limit.

Next, the deceleration control unit 40G determines whether to continue the deceleration control started in step S118 (step S122). For example, if the brake pedal 13B is operated while the vehicle 1 is moving, the deceleration control unit 40G determines to continue the deceleration control. In particular, if the vehicle speed detected by the vehicle speed sensor 21 exceeds 0 and the brake stroke sensor 19 detects a brake stroke indicating depression of the brake pedal 13, the deceleration control unit 40G determines to continue the deceleration control.

The deceleration control unit 40G repeats a positive determination (step S122: Yes) until it determines not to continue deceleration control (step S122: No). When the deceleration control unit 40G determines not to continue deceleration control (step S122: No), it ends this routine.

On the other hand, if the second judgment unit 40F determines that the vehicle 1 cannot be decelerated by deceleration control (step S114: No), the evacuation travel control unit 40E sets the first speed as the vehicle speed limit value for the evacuation travel speed (step S124). Then, the evacuation travel control unit 40E executes evacuation travel control to control the traction motor-generator 16 so that the vehicle 1 performs evacuation travel using the first speed as the vehicle speed limit value (step S126). In particular, the evacuation travel control unit 40E controls the traction motor-generator 16 via the drive machine ECU 38 so that the vehicle travels using only power from the power storage device 18 to drive the traction motor-generator 16, and at the first speed set as the vehicle speed limit value. Then, this routine ends.

As described above, the emergency travel control device 40 of this embodiment is provided in the vehicle 1. The vehicle 1 includes a traction motor-generator 16 that supplies driving force to the drive wheels 22 and generates electricity through regenerative braking, an internal combustion engine 12, a motoring motor-generator 14 that is driven by the internal combustion engine 12 and generates electricity, an electric storage device 18 that is charged and discharged by the traction motor-generator 16 and the motoring motor-generator 14, and a brake booster 11 that amplifies the force applied to the brake pedal 13 using the intake negative pressure of the internal combustion engine 12. The emergency travel control device 40 includes a negative pressure ensuring control unit 40C, a first determination unit 40D, and an emergency travel control unit 40E. The negative pressure ensuring control unit 40C executes negative pressure ensuring control so that the brake booster 11 maintains a first negative pressure greater than zero when the internal combustion engine 12 stops operating due to an abnormality in the internal combustion engine 12. The first determination unit 40D determines whether a first negative pressure has been secured in the brake booster 11 through negative pressure securing control. If the evacuation travel control unit 40E determines that the first negative pressure has been secured, it sets a second speed, which is faster than a first speed that is predetermined as the vehicle speed limit for the evacuation travel speed, as the vehicle speed limit, and controls the vehicle to perform evacuation travel.

For this reason, the evacuation travel control device 40 of this embodiment can increase the vehicle speed limit value during evacuation travel from the first speed to the second speed when evacuation travel is required due to an abnormality in the internal combustion engine 12, and can ensure an appropriate braking distance. Therefore, the evacuation travel control device 40 of this embodiment can reduce the risks associated with increased speed differences with other vehicles that occur when evacuation travel is performed at an extremely low vehicle speed, and can perform evacuation travel that ensures an appropriate braking distance.

Therefore, the evacuation driving control device 40 of this embodiment can improve driving performance during evacuation driving.

In addition, in the evacuation travel control device 40 of this embodiment, if the first negative pressure in the brake booster 11 cannot be secured by negative pressure securing control, the deceleration control unit 40G initiates deceleration control. Then, once deceleration control is initiated by the deceleration control unit 40G, the evacuation travel control unit 40E sets the second speed as the vehicle speed limit value and controls the vehicle to perform evacuation travel.

Depending on the severity of the abnormality in the internal combustion engine 12, it may be difficult to motor the internal combustion engine 12 using the motoring motor-generator 14. Even in such cases, the deceleration control unit 40G performs deceleration control using a drive mechanism other than the brake booster 11, thereby increasing the vehicle speed limit value during evacuation travel from the first speed to the second speed and ensuring an appropriate braking distance.

In addition, the deceleration control unit 40G performs deceleration control by controlling the drive of the electric parking brake 23.

If the first negative pressure of the brake booster 11 cannot be secured, one method is to increase the regenerative deceleration rate and perform deceleration control using the traction motor generator 16. However, if the power storage device 18 is fully charged or the vehicle 1 is in an extremely low temperature environment, regenerative braking may not be possible. On the other hand, deceleration control using drive control of the electric parking brake 23 allows for stable deceleration control regardless of the charge status of the power storage device 18 or the ambient temperature of the vehicle 1.

Therefore, by having the deceleration control unit 40G perform deceleration control by controlling the drive of the electric parking brake 23, in addition to the above effects, it is possible to stably improve driving performance during evacuation driving.

In this embodiment, the negative pressure ensuring control unit 40C executes negative pressure ensuring control to ensure the first negative pressure when the drive of the internal combustion engine 12 stops due to an abnormality in the internal combustion engine 12. Furthermore, the embodiment has been described in which, if the first determination unit 40D determines that the first negative pressure has been ensured, the evacuation travel control unit 40E sets the second speed as the vehicle speed limit value and controls the vehicle to perform evacuation travel.

However, after the internal combustion engine 12 has stopped operating due to an abnormality in the internal combustion engine 12 and before the negative pressure assurance control is performed by the negative pressure assurance control unit 40C, the first determination unit 40D may further determine whether the first negative pressure is assured in the brake booster 11. If it is determined that the first negative pressure is assured before the negative pressure assurance control is performed, the negative pressure assurance control may be omitted, and the evacuation travel control unit 40E may perform evacuation travel control with the second speed set as the vehicle speed limit value. If it is determined that the first negative pressure is not assured in the brake booster 11, the negative pressure assurance control unit 40C may perform negative pressure assurance control.

The programs for executing the above processes executed by the evacuation driving control device 40 of this embodiment may be stored on the HDD. Alternatively, the programs for executing the above processes executed by the evacuation driving control device 40 of this embodiment may be provided in advance in ROM 11B.

The program for executing the above-described processes executed by the evacuation travel control device 40 of this embodiment may be provided as a computer program product by being stored in an installable or executable file format on a computer-readable storage medium such as a CD-ROM, CD-R, memory card, DVD (Digital Versatile Disc), or flexible disk (FD). The program for executing the above-described processes executed by the evacuation travel control device 40 of this embodiment may also be stored on a computer connected to a network such as the Internet and provided by being downloaded via the network. The program for executing the above-described processes executed by the evacuation travel control device 40 of this embodiment may also be provided or distributed via a network such as the Internet.

Although an embodiment of the present invention has been described above, the above embodiment is presented as an example and is not intended to limit the scope of the invention. This novel embodiment can be embodied in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. This embodiment and its variations are included within the scope and spirit of the invention, and are also included in the invention and its equivalents as set forth in the claims.

REFERENCE SIGNS LIST 1 Vehicle 11 Brake booster 12 Internal combustion engine 14 Motoring motor generator 16 Traveling motor generator 18 Electricity storage device 23 Electric parking brake 40 Evacuation travel control device 40C Negative pressure ensuring control unit 40D First determination unit 40E Evacuation travel control unit 40F Second determination unit 40G Deceleration control unit

Claims (3)

The brake booster is provided on a vehicle equipped with a traction motor generator that supplies driving force to drive wheels and generates electricity through regenerative braking, an internal combustion engine, a motoring motor generator that is driven by the internal combustion engine and generates electricity, an electricity storage device that is charged and discharged by the traction motor generator and the motoring motor generator, and a brake booster that amplifies brake pedal force by utilizing intake negative pressure of the internal combustion engine,
a negative pressure ensuring control unit that executes negative pressure ensuring control so that the brake booster ensures a first negative pressure greater than 0 when the internal combustion engine stops operating due to an abnormality in the internal combustion engine;
a first determination unit that determines whether the first negative pressure is ensured in the brake booster by the negative pressure ensuring control;
an evacuation travel control unit that, when it is determined that the first negative pressure is ensured, sets a second speed higher than a first speed, which is a predetermined vehicle speed limit value for an evacuation travel speed, as the vehicle speed limit value, and controls the vehicle to perform evacuation travel;
An evacuation driving control device comprising: a second determination unit that determines whether or not the vehicle can be decelerated by deceleration control when it is determined that the first negative pressure is not ensured;
a deceleration control unit that starts the deceleration control when it is determined that deceleration is possible by the deceleration control;
Equipped with
The evacuation travel control unit
When it is determined that deceleration is possible by the deceleration control, the second speed is set as the vehicle speed limit value, and control is performed so that the vehicle travels to evacuate.
The emergency driving control device according to claim 1 . The deceleration control unit
When it is determined that deceleration is possible by the deceleration control, the deceleration control is started, which is drive control of an electric parking brake based on detection results of a brake stroke sensor and a vehicle speed sensor provided on the vehicle.
The emergency driving control device according to claim 2 .