JP2017159813A - Vehicular braking device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a state in which a frictional braking member comes into a fading state.SOLUTION: A vehicular braking device 11 includes: a frictional braking mechanism 37 which generates a frictional braking force on a wheel of a vehicle 12; an accelerator pedal 21 which is operated at the time of acceleration/deceleration of the vehicle 12, with an acceleration region and a deceleration region set within an operation range related to acceleration/deceleration; a driving and braking mechanism 35 which generates a driving force and an engine braking force on the vehicle 12; a target acceleration/deceleration setting part 71 which sets a target acceleration/deceleration TG based on acceleration/deceleration operation with the accelerator pedal 21; and an acceleration/deceleration control part 73 which performs braking control with the vehicle 12 so that an actual braking force follows a target braking force of a magnitude which is based on the target acceleration/deceleration TG. The acceleration/deceleration control part 73, as an actual braking force, distributes an engine braking force to the frictional braking force in priority, and if the engine braking force of the distributed magnitude does not satisfy the target braking force, distributes the frictional braking force of an amount of insufficient value as an actual brake force.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a vehicle braking device that generates a driving force and an engine braking force using an internal combustion engine.

  In a vehicle that uses an internal combustion engine to generate a driving force and a braking force, a driving force (driving torque) corresponding to the amount of operation of the accelerator pedal is generated in the internal combustion engine and the fuel supply is shut off when the accelerator is off. Thus, an engine braking force (generally referred to as “engine brake”) is generated by linking the internal combustion engine and a power transmission mechanism (including a transmission) to reduce the vehicle speed.

  Patent Document 1 discloses an invention of a travel control device that executes one-pedal mode control for controlling both driving force and braking force of a vehicle according to an operation amount of one pedal in a vehicle equipped with an internal combustion engine. Has been. The travel control device according to Patent Document 1 is based on temperature measuring means for measuring the temperature of a friction braking member such as a brake pad or a disc rotor that generates a friction braking force, and the temperature of the friction braking member measured by the temperature measuring means. Target braking force correcting means for correcting the target braking force.

  According to the travel control device according to Patent Document 1, since the friction braking force can be appropriately generated based on the temperature of the friction braking member, a stable friction braking force can be obtained regardless of the temperature of the friction braking member. Can do.

JP 2001-071794 A

  In the travel control device according to Patent Literature 1, if a friction brake (friction braking force) is frequently used, there is a concern that the friction braking member may overheat and fall into a fade state. Therefore, when application of a friction braking force is assumed as a braking force based on the one-pedal mode control, consideration is required to suppress a situation in which the friction braking member falls into a fade state. In this regard, the travel control device according to Patent Document 1 does not mention consideration for suppressing a situation in which the friction braking member falls into a fade state.

  The present invention has been made in view of the above circumstances, and in a vehicle that generates a driving force and a braking force using an internal combustion engine, an application of a friction braking force as an actual braking force based on a deceleration operation of an acceleration / deceleration operator is provided. The present invention has an object to provide a vehicular braking apparatus capable of suppressing a situation in which a friction braking member falls into a faded state.

  In order to achieve the above object, the invention according to (1) is operated at the time of accelerating and decelerating the friction braking unit that generates a friction braking force by causing a friction braking member to act on a vehicle wheel, An acceleration / deceleration operator having an acceleration region and a deceleration region set in an operation range related to the acceleration / deceleration, an internal combustion engine and a power transmission mechanism mounted on the vehicle, and driving force and engine control for the vehicle. A driving / braking mechanism that generates power, a target deceleration setting unit that sets a target deceleration based on the deceleration operation when the acceleration / deceleration operator is decelerated, and the acceleration / deceleration operator is decelerated. The actual braking force acting on the vehicle is distributed according to a predetermined rule so as to follow a target braking force having a magnitude based on the target deceleration set by the target deceleration setting unit. Said Ma A braking control unit that performs braking control of the vehicle using both braking force and engine braking force related to the driving braking mechanism or actual braking force including the engine braking force, and the braking control unit includes the actual braking force. As the braking force, the engine braking force is preferentially distributed according to the rules with respect to the friction braking force, and the engine braking force of the allocated magnitude is less than the target braking force, the deficiency The most important feature is that the friction braking force is distributed as an actual braking force.

  In the invention according to (1), the braking control unit preferentially distributes the engine braking force with respect to the friction braking force according to a predetermined rule as the actual braking force, and the engine braking force of the allocated magnitude is the target. When the braking force is not satisfied, a configuration in which the friction braking force is distributed as the actual braking force corresponding to the shortage is adopted. The target braking force having a magnitude based on the target deceleration may be obtained by multiplying the target deceleration by the vehicle mass.

  According to the invention according to (1), the braking control unit preferentially distributes the engine braking force with respect to the friction braking force according to a predetermined rule as the actual braking force, and the engine braking force of the allocated magnitude. When the braking force is less than the target braking force, the frictional braking force is distributed as the actual braking force of the shortage, so that the application of the frictional braking force is assumed as the actual braking force based on the deceleration operation of the acceleration / deceleration operator. The situation in which the friction braking member falls into a fade state can be suppressed.

  The invention according to (2) is the vehicle braking device according to (1), further comprising a gradient information acquisition unit that acquires gradient information relating to a road on which the vehicle is traveling, and the braking control unit Is characterized in that when the vehicle is traveling on a downhill road, the ratio of the engine braking force to the actual braking force is increased as compared with the case where the vehicle is traveling on a flat road.

Generally, when the vehicle is traveling on a downhill road, it is assumed that the friction braking member falls into a fade state.
Therefore, in the invention according to (2), the braking control unit is configured such that when the vehicle is traveling on a downhill road, the ratio of the engine braking force in the actual braking force as compared to the case where the vehicle is traveling on a flat road. It was decided to adopt a configuration that increases

  According to the invention according to (2), when the vehicle is traveling on a downhill road, the ratio of the frictional braking force in the actual braking force is relatively larger than when the vehicle is traveling on a flat road. Since it reduces, the situation where a friction braking member falls into a fade state can be suppressed.

  The invention according to (3) is the vehicle braking device according to (2), in which the braking control unit has a gradient value based on the gradient information when the vehicle is traveling on a downhill road. As the degree of exceeding a predetermined gradient threshold increases, the ratio of the engine braking force to the actual braking force is increased.

  According to the invention relating to (3), when the vehicle is traveling on a downhill road, the braking control unit increases the degree that the gradient value based on the gradient information exceeds a predetermined gradient threshold value, that is, the downhill road suddenly increases. As the gradient is increased, the proportion of the actual braking force occupied by the engine braking force is increased. As a result, the proportion of the actual braking force occupied by the friction braking force is relatively further reduced as compared with the invention according to (2). The situation where the friction braking member falls into a fade state can be further suppressed.

  Moreover, the invention which concerns on (4) is a vehicle braking device as described in any one of (1)-(3), Comprising: The temperature information acquisition part which acquires the temperature information of the said friction braking member is further provided, When the temperature value of the friction braking member based on the temperature information exceeds a predetermined temperature threshold, the braking control unit is more effective than the case where the temperature value of the friction braking member is equal to or lower than the predetermined temperature threshold. A ratio of the braking force occupied by the engine braking force is increased.

The cause of the friction braking member falling into a fade state is overheating of the friction braking member due to frequent use of the friction braking force. For this reason, when the friction braking member is in an overheated state, a situation in which the friction braking member falls into a fade state is assumed. Therefore, it is preferable to take a countermeasure.
Therefore, in the invention according to (4), the braking control unit controls the actual control when the temperature value of the friction braking member exceeds a predetermined temperature threshold as compared with the case where the temperature value of the friction braking member is equal to or lower than the temperature threshold. It was decided to adopt a configuration that increases the proportion of the engine braking force in the power. As the predetermined temperature threshold, for example, a temperature value that requires caution as a situation where the friction braking member falls into a fade state may be appropriately adopted.

  According to the invention according to (4), when the temperature value of the friction braking member exceeds a predetermined temperature threshold, the ratio of the friction braking force in the actual braking force is relatively reduced, so that the friction braking member is The situation of falling into a fade state can be suppressed.

  The invention according to (5) is the vehicle braking device according to (4), in which the braking control unit increases the degree that the temperature value of the friction braking member exceeds the temperature threshold. A ratio of the braking force occupied by the engine braking force is increased.

  According to the invention according to (5), the braking control unit increases the proportion of the actual braking force occupied by the engine braking force as the temperature value of the friction braking member exceeds the temperature threshold. Compared with the invention which concerns, as a result of further reducing the ratio which a friction braking force occupies among actual braking forces, the situation where a friction braking member falls into a fade state can be suppressed further.

  The invention according to (6) is the vehicular braking apparatus according to any one of (1) to (5), in which the engine braking force related to the drive braking mechanism is determined by the ignition timing of the internal combustion engine. Is generated by at least one of ignition timing control that delays the fuel, fuel cutoff control that shuts off fuel supply to the internal combustion engine, and shift control that downshifts the transmission of the power transmission mechanism, The braking control unit executes control related to at least any one or a combination of the ignition timing control, the fuel cutoff control, and the shift control, so that the magnitude of the actual braking force is allocated. An engine braking force is generated.

In general, the engine braking force related to the drive braking mechanism is generated by ignition timing control, fuel cutoff control, and shift control. Here, the magnitude and adjustment range of the engine braking force that can be generated are different in each of the ignition timing control, the fuel cutoff control, and the shift control.
Therefore, in order to obtain an engine braking force of a required magnitude, in the invention according to (6), the braking control unit includes at least one or a combination of at least one of ignition timing control, fuel cutoff control, and shift control. By executing the control according to the above, a configuration is adopted in which the engine braking force having the (required) magnitude distributed as the actual braking force is generated.

  According to the invention according to (6), the braking control unit executes the control related to at least any one or a combination of ignition timing control, fuel cutoff control, and shift control as the actual braking force. Since the engine braking force of the required required amount is generated, it is possible to suppress the driver from feeling uncomfortable with the generation of the engine braking force.

  The invention according to (7) is the vehicle braking device according to (6), in which the magnitude and adjustment range of the engine braking force that can be generated are the ignition timing control, the fuel cutoff control, The order of the shift control is large, and the braking control unit increases the magnitude of the engine braking force allocated as the actual braking force in the order of the ignition timing control, the fuel cutoff control, and the shift control. The main feature is that the control to be executed is shifted sequentially.

  Further, according to the invention according to (7), the braking control unit increases the order of the ignition timing control, the fuel cutoff control, and the shift control as the (required) magnitude of the engine braking force distributed as the actual braking force increases. Therefore, in order to sequentially shift the control that is mainly executed, for example, in order to obtain the required engine braking force when the vehicle is traveling at a relatively high vehicle speed, the influence on the passengers in the passenger compartment is not considered. Compared to the case where the engine braking force is generated suddenly by downshift transmission control accompanied by a sudden increase in engine rotation speed, the engine is operated with the generation of the engine braking force based on the deceleration operation of the acceleration / deceleration operator. The situation that makes the person feel uncomfortable can be suppressed.

  According to the vehicle braking apparatus of the present invention, it is assumed that the friction braking force is applied as the actual braking force based on the deceleration operation of the acceleration / deceleration operator in the vehicle that generates the driving force and the engine braking force using the internal combustion engine. In this case, it is possible to suppress a situation in which the friction braking member falls into a fade state.

It is a block block diagram showing the outline | summary of the vehicle braking device which concerns on embodiment of this invention. It is a flowchart figure with which it uses for operation | movement description of the braking device for vehicles. It is a time chart figure used for operation | movement description of the braking device 11 for vehicles, (a) is a time transition of the target deceleration based on an accelerator pedal operation, (b) is a time transition of an engine output, (c) is a CVT gear ratio. (D) represents the time transition of the braking force.

Hereinafter, a vehicle braking device according to an embodiment of the present invention will be described in detail with reference to the drawings.
Note that, in the drawings shown below, in principle, common reference numerals are assigned between members having a common function or between members having functions corresponding to each other. Further, for convenience of explanation, the size and shape of the member may be schematically represented by being deformed or exaggerated.

[Vehicle Braking Device 11 According to an Embodiment of the Present Invention]
A vehicle braking device 11 according to an embodiment of the present invention will be described with reference to FIG. 1 exemplifying a vehicle 12 on which an internal combustion engine 41 is mounted. FIG. 1 is a block diagram showing an outline of the vehicle braking device 11.

As shown in FIG. 1, the vehicle braking device 11 includes an acceleration / deceleration ECU (Electronic Control Unit) 13, an ABS-ECU 15, and a VSA-ECU 17 via a communication medium 19 such as a CAN (Control Area Network). Are connected to each other so that data can be exchanged between them.
Each of the acceleration / deceleration ECU 13, the ABS-ECU 15, and the VSA-ECU 17 is configured by a microcomputer including a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like. The microcomputer reads and executes programs and data stored in the ROM, and operates so as to perform execution control of various functions of the acceleration / deceleration ECU 13, the ABS-ECU 15, and the VSA-ECU 17.

  The acceleration / deceleration ECU (Electronic Control Unit) 13 has a function of performing acceleration / deceleration control of the vehicle 12. The internal configuration of the acceleration / deceleration ECU 13 will be described later in detail. The ABS-ECU 15 has a function of preventing the wheels (not shown) from being locked during the braking operation of the vehicle 12. The VSA (“VSA” is a registered trademark) -ECU 17 has a function of supporting behavior stabilization related to the vehicle 12.

As shown in FIG. 1, the communication medium 19 includes an accelerator pedal sensor 23 for detecting a stepping operation amount from an initial position of the accelerator pedal 21 (a state in which the operation by the driver is released), and a stepping operation amount of the brake pedal 25. A brake pedal sensor 27 for detecting the vehicle speed, a vehicle speed sensor 29 for detecting the speed (vehicle speed) of the vehicle 12, a front-rear G sensor 31 for detecting the longitudinal acceleration / deceleration generated in the vehicle 12, and a gradient of the road surface on which the vehicle 12 exists. A gradient sensor 32, an AP operation mode changeover switch 33, a braking mode changeover switch 34, a driving braking mechanism 35, and a friction braking mechanism 37 are connected.
Various data detected by the accelerator pedal sensor 23, the brake pedal sensor 27, the vehicle speed sensor 29, the front / rear G sensor 31, the gradient sensor 32, the mode switching data related to the AP operation mode switching switch 33, and the braking mode switching switch 34 are communication media. 19 is sent to the acceleration / deceleration ECU 13, the ABS-ECU 15, and the VSA-ECU 17.
The accelerator pedal 21 operated when the vehicle 12 is accelerated / decelerated corresponds to the “acceleration / deceleration operator” of the present invention.

The AP operation mode switching switch 33 is a switch operated when switching the operation mode of the accelerator pedal 21 (hereinafter referred to as “AP operation mode”). The AP operation mode changeover switch 33 is provided on an instrument panel (not shown) in the vehicle cabin. As the AP operation mode, a normal mode in which only acceleration control corresponding to the depression operation amount of the accelerator pedal 21 is performed, and a one-pedal mode in which acceleration / deceleration control is performed according to the depression / retraction operation amount of the accelerator pedal 21 are set. ing. Details of the one-pedal mode will be described later.
The AP operation mode changeover switch 33 may adopt a configuration that omits the driver's operation by setting the one-pedal mode by default.

  When the AP operation mode is set to the one-pedal mode, the braking mode changeover switch 34 is used to variably set the deceleration control amount (target deceleration) based on the return operation amount of the accelerator pedal 21 in, for example, three stages. It is a switch operated by The braking mode changeover switch 34 is provided on an instrument panel or the like in the passenger compartment.

  As shown in FIG. 1, the driving / braking mechanism 35 includes an internal combustion engine 41 that is a drive source of the vehicle 12 and a continuously variable transmission (CVT) 43. However, the continuously variable transmission 43 may be a normal (stepped) transmission. The driving / braking mechanism 35 has a function of driving the vehicle 12 based on a control command of the acceleration / deceleration ECU 13 and generating an engine braking force as necessary.

  The friction braking mechanism 37 includes components related to friction braking, such as a friction braking member 45 including a brake pad and a disk rotor, and a hydraulic system 47. The friction braking mechanism 37 has a function of generating a friction braking force on the wheels of the vehicle 12 based on a control command of the acceleration / deceleration ECU 13. The friction braking member 45 is provided with a rotor temperature sensor 49 that detects the temperature of the disk rotor. Rotor temperature data detected by the rotor temperature sensor 49 is sent to the acceleration / deceleration ECU 13 via the communication medium 19. The friction braking mechanism 37 corresponds to the “friction braking portion” of the present invention.

[Internal configuration of acceleration / deceleration ECU 13]
Next, the internal configuration of the acceleration / deceleration ECU 13 will be described with reference to FIG.
As shown in FIG. 1, the acceleration / deceleration ECU 13 includes an input / output unit 61, a calculation unit 63, and a storage unit 65.

  The input / output unit 61 includes, as input data, acceleration / deceleration operation amount data (AP acceleration / deceleration operation amount data) related to the accelerator pedal sensor 23, braking operation amount data (BP braking operation amount data) related to the brake pedal sensor 27, and vehicle speed sensor. 29, vehicle speed data, front / rear G data related to the front / rear G sensor 31, gradient data related to the gradient sensor 32, rotor temperature data related to the rotor temperature sensor 49, mode switching related to the AP operation mode switch 33 and the brake mode switch 34. While inputting data and the like, it has a function of outputting drive braking control data related to the internal combustion engine 41 and friction braking control data related to the friction braking member 45 as output data. The input / output unit 61 corresponds to a “gradient information acquisition unit” and a “temperature information acquisition unit” of the present invention.

  The calculation unit 63 relates to the internal combustion engine 41 based on the AP acceleration / deceleration operation amount data, BP braking operation amount data, vehicle speed data, longitudinal G data, gradient data, rotor temperature data, mode switching data, charge degree data, and the like. It has a function of calculating driving braking control data, friction braking control data related to the friction braking member 45, and the like. More specifically, the calculation unit 63 includes a target acceleration / deceleration setting unit 71 and an acceleration / deceleration control unit 73.

  The target acceleration / deceleration setting unit 71 is a target value related to acceleration / deceleration of the vehicle 12 based on input data such as AP acceleration / deceleration operation amount data and BP braking operation amount data (sometimes referred to as “target acceleration / deceleration”). Has the function of setting.

  Specifically, in the normal mode, the target acceleration / deceleration setting unit 71 sets the target acceleration based on the BP braking operation amount data, and sets the target acceleration based on the AP acceleration / deceleration operation amount data. That is, in the normal mode, only the acceleration of the vehicle 12 is controlled according to the AP acceleration / deceleration operation amount data. As a result, the entire depression / step-back operation range of the accelerator pedal 21 (the range in which the AP acceleration / deceleration operation amount data can be obtained) is used in principle for accelerating the vehicle 12. However, in the normal mode, the engine braking force generated when the accelerator pedal 21 is stepped back to the vicinity of the initial position acts normally.

  On the other hand, in the one pedal mode, the target acceleration / deceleration setting unit 71 is the same as the normal mode in that the target deceleration is set based on the BP braking operation amount data, but based on the AP acceleration / deceleration operation amount data. The point which sets both the target acceleration and deceleration (target acceleration / deceleration) is different from the case in the normal mode.

  In order to set both acceleration and deceleration by operating a single pedal (accelerator pedal 21), the relationship of the target acceleration / deceleration corresponding to the depression operation amount (AP acceleration / deceleration operation amount data) related to the accelerator pedal 21 is determined by driving. The maximum target deceleration TG is associated with the initial position in a state where the accelerator pedal 21 is released by the user, while the target deceleration TG decreases as the degree of depression increases in the deceleration region starting from the initial position. Is set to As a result, in the one-pedal mode, both acceleration and deceleration of the vehicle 12 are controlled according to the AP acceleration / deceleration operation amount data.

  Of the target deceleration TG corresponding to the operation range (the range in which the AP acceleration / deceleration operation amount data can be obtained) related to the depression / return of the accelerator pedal 21, for example, as shown in FIG. An area for deceleration with an initial value (target deceleration: zero) P0 as a starting point and a boundary threshold value P1 as an ending point is referred to as a “deceleration area”. An area for acceleration where the accelerator pedal 23 is depressed by exceeding the boundary threshold value P1 is referred to as an “acceleration area”. Note that the range of the deceleration region and the acceleration region (the size of the boundary threshold value P1) is variable according to the increase or decrease of the vehicle speed.

  The acceleration / deceleration control unit 73 has a function of performing acceleration / deceleration control of the vehicle 12 based on input data such as vehicle speed data, front / rear G data, and the target acceleration / deceleration set by the target acceleration / deceleration setting unit 71. In order to realize such acceleration / deceleration control, the acceleration / deceleration control unit 73 includes an engine control unit 75 and a brake control unit 77. The acceleration / deceleration control unit 73 corresponds to the “braking control unit” of the present invention.

  Based on the target acceleration / deceleration set by the target acceleration / deceleration setting unit 71, the engine control unit 75 controls the driving / braking mechanism 35 that exhibits the driving force and the engine braking force related to the internal combustion engine 41. The brake control unit 77 controls the friction braking mechanism 37 that exerts the friction braking force based on the target acceleration / deceleration set by the target acceleration / deceleration setting unit 71.

  The storage unit 65 includes a nonvolatile memory and a volatile memory (not shown). The nonvolatile memory is, for example, a flash memory or an EEPROM (Electrically Erasable Programmable Read Only Memory), and stores a program for executing various processes in the arithmetic unit 63. The volatile memory is, for example, a DRAM (Dynamic Random Access Memory), and input / output data and calculation results are temporarily stored when various processes in the calculation unit 63 are executed.

  Further, in the storage unit 65, the TG first threshold TGth1, the TG second threshold TGth2, and the TG third threshold TGth3 regarding the target deceleration TG set by the target acceleration / deceleration setting unit 71 based on the deceleration operation of the accelerator pedal 21. Are stored. The TG first threshold value TGth1, the TG second threshold value TGth2, and the TG third threshold value TGth3 are the braking force (engine braking force / friction) for realizing the target deceleration TG based on the deceleration operation of the accelerator pedal 21 in the acceleration / deceleration ECU 13. Reference is made when setting the type and distribution ratio of braking force. The TG first threshold TGth1, the TG second threshold TGth2, and the TG third threshold TGth3 will be described later in detail.

Further, the storage unit 65 stores a gradient threshold SLth for the gradient value SL detected by the gradient sensor 32. The gradient threshold SLth is referred to when the acceleration / deceleration ECU 13 determines whether or not the vehicle 12 is traveling on a downhill road.
Further, the storage unit 65 stores a temperature threshold RTth for the rotor temperature value RT detected by the rotor temperature sensor 49. The temperature threshold RTth is referred to when the acceleration / deceleration ECU 13 determines whether or not it is necessary to be wary of a situation in which the friction braking member 45 falls into a fade state.

[Operation of Vehicle Braking Device 11 According to Embodiment of the Present Invention]
Next, the operation of the vehicle braking device 11 according to the embodiment of the present invention will be described with reference to FIG. FIG. 2 is a flowchart for explaining the operation of the vehicle braking device.
However, it is assumed that the AP operation mode is set to the one pedal mode. Further, it is assumed that the accelerator pedal 21 is decelerated.

  In step S <b> 11 shown in FIG. 2, the acceleration / deceleration ECU 13 inputs various data including AP acceleration / deceleration operation amount data, gradient value data SL, and rotor temperature value data RT via the communication medium 19.

  In step S12, the target acceleration / deceleration setting unit 71 of the acceleration / deceleration ECU 13 sets a target deceleration TG based on the deceleration operation of the accelerator pedal 21 based on the AP acceleration / deceleration operation amount data.

  In step S13, the acceleration / deceleration control unit 73 of the acceleration / deceleration ECU 13 determines whether or not the target deceleration TG set in step S12 exceeds the TG first threshold TGth1. As the TG first threshold value TGth1, a relatively small value in a predetermined deceleration range may be appropriately employed as the deceleration requested by the driver.

  As a result of the determination in step S13, if it is determined that the target deceleration TG exceeds the TG first threshold TGth1 (“Yes” in step S13), the acceleration / deceleration ECU 13 moves the process flow to step S15. Let it jump. On the other hand, when it is determined that the target deceleration TG does not exceed the TG first threshold TGth1 (“No” in step S13) as a result of the determination in step S13, the acceleration / deceleration ECU 13 follows the flow of processing. To step S14.

  In step S14, the acceleration / deceleration control unit 73 of the acceleration / deceleration ECU 13 performs control for realizing the target deceleration TG based on the determination result that the target deceleration TG is a relatively small value in the deceleration range. Ignition timing control (retard) that retards the ignition timing while maintaining the shift position of the continuously variable transmission (CVT) 43 in order to select engine braking force as power and obtain engine braking force based on the target deceleration TG Execute. Next, the acceleration / deceleration ECU 13 returns the process flow to step S11, and sequentially executes the subsequent processes.

  In step S15, the acceleration / deceleration control unit 73 of the acceleration / deceleration ECU 13 determines whether or not the target deceleration TG set in step S12 exceeds the TG second threshold TGth2. As the TG second threshold value TGth2, a moderate value in the deceleration range may be appropriately employed as the deceleration requested by the driver.

  As a result of the determination in step S15, when it is determined that the target deceleration TG exceeds the TG second threshold value TGth2 (“Yes” in step S15), the acceleration / deceleration ECU 13 moves the process flow to step S17. Let it jump. On the other hand, as a result of the determination in step S15, when it is determined that the target deceleration TG does not exceed the TG second threshold TGth2 (“No” in step S15), the acceleration / deceleration ECU 13 follows the processing flow. The process proceeds to step S16.

  In step S16, the acceleration / deceleration control unit 73 of the acceleration / deceleration ECU 13 sets the target deceleration TG based on the determination result that the target deceleration TG is a small value within the deceleration range (TGth1 <TG <TGth2). The engine braking force is selected as the braking force for realizing the deceleration TG, and the fuel in a state where the shift position of the continuously variable transmission (CVT) 43 is held in order to obtain the engine braking force based on the target deceleration TG. Fuel cutoff control (fuel cut) is performed to shut off the supply. Next, the acceleration / deceleration ECU 13 returns the process flow to step S11, and sequentially executes the subsequent processes.

  In step S17, the acceleration / deceleration control unit 73 of the acceleration / deceleration ECU 13 determines whether or not the target deceleration TG set in step S12 exceeds the TG third threshold TGth3. As the TG third threshold TGth3, a relatively large value in the deceleration range may be appropriately adopted as the deceleration requested by the driver.

  As a result of the determination in step S17, when it is determined that the target deceleration TG exceeds the TG third threshold value TGth3 (“Yes” in step S17), the acceleration / deceleration ECU 13 proceeds to step S19. Let it jump. On the other hand, as a result of the determination in step S17, if it is determined that the target deceleration TG does not exceed the TG third threshold TGth3 (“No” in step S17), the acceleration / deceleration ECU 13 follows the processing flow. The process proceeds to step S18.

  In step S18, the acceleration / deceleration control unit 73 of the acceleration / deceleration ECU 13 sets the target deceleration TG based on the determination result that the target deceleration TG is a medium value (TGth2 <TG <TGth3) in the deceleration range. The engine braking force is selected as the braking force for realizing the deceleration TG, and the fuel cutoff control and the shift control for downshifting the continuously variable transmission CVT43 are executed to obtain the engine braking force based on the target deceleration TG. . Next, the acceleration / deceleration ECU 13 returns the process flow to step S11, and sequentially executes the subsequent processes.

  In step S19, the acceleration / deceleration control unit 73 of the acceleration / deceleration ECU 13 determines the target deceleration TG based on the determination result that the target deceleration TG is a relatively large value (TG> TGth3) in the deceleration range. The engine braking force is selected as the braking force to be realized, and fuel cutoff control, shift control, and friction braking control are executed to obtain the engine braking force based on the target deceleration TG. Next, the acceleration / deceleration ECU 13 returns the process flow to step S11, and sequentially executes the subsequent processes.

[Description of Operation of Vehicle Braking Device 11 Based on Time Chart]
Next, regarding the operation of the vehicle brake device 11 according to the embodiment of the present invention, the vehicle 12 that has been traveling at a constant speed in a state where the one-pedal mode is set to ON performs a step-back operation of the accelerator pedal 21. An example of decelerating with reference to FIG. 3 will be described as an example. 3A and 3B are time charts for explaining the operation of the vehicle braking device 11. FIG. 3A is a time transition of the target deceleration based on the accelerator pedal operation, FIG. 3B is a time transition of the engine output, and FIG. Represents the time transition of the CVT gear ratio, and (c) represents the time transition of the braking force.

At times t0 to t1 shown in FIG. 3, a deceleration operation for gradually depressing the accelerator pedal 21 is performed. With this deceleration operation, the target deceleration TG gradually decreases (see FIG. 3A). Times t0 to t1 shown in FIG. 3 correspond to the “acceleration region” of the present invention. The AP acceleration / deceleration operation amount at time t1 corresponds to the “boundary threshold” of the present invention.
At the same time t0 to t1, as the target deceleration TG gradually decreases, the engine output also gradually decreases (see FIG. 3B). The CVT gear ratio is gradually upshifted (see FIG. 3C). The braking force for the vehicle 12 is not acting (see FIG. 3D).

At times t1 to t3 shown in FIG. 3, the accelerator pedal 21 is gently decelerated. With this deceleration operation, the target deceleration TG gradually decreases (see FIG. 3A).
At the same time t1 to t3, as the target deceleration TG gradually decreases, the engine output gradually decreases by ignition timing control that delays the ignition timing (see FIG. 3B). The CVT gear ratio holds the previous shift position (see FIG. 3C).
At the same time t1 to t3, the engine braking force derived from the ignition timing control is acting alone as the actual braking force (see FIG. 3 (d)). In the embodiment according to the present invention, when the engine braking force is preferentially distributed over the friction braking force, and the engine braking force of the allocated amount is less than the target deceleration TG, the insufficient actual braking force is obtained. This is because the engine braking force derived from the ignition timing control satisfies the target deceleration TG at the same time t1 to t3.
Note that, at time t2 shown in FIG. 3, the target deceleration TG showing a decreasing tendency has reached the TG first threshold TGth1. In response to this, after time t3 shown in FIG. 3, the main control for generating the engine braking force has shifted from the ignition timing control to the fuel cutoff control. Incidentally, the time interval between times t2 and t3 is a time lag that occurs when the main control for generating the engine braking force is shifted from the ignition timing control to the fuel cutoff control.

From time t3 to time t4 shown in FIG. 3, the accelerator pedal 21 continues to be moderately decelerated. With this deceleration operation, the target deceleration TG gradually decreases (see FIG. 3A).
At time t3, the main control for generating the engine braking force is shifted from the ignition timing control to the fuel cutoff control (see FIG. 3B). At the same time t3 to t4, the engine output is maintained at a constant value by the fuel cutoff control (see FIG. 3B). The CVT gear ratio holds the previous shift position (see FIG. 3C).
At the same time t3 to t4, the engine braking force derived from the fuel cutoff control is acting alone as the actual braking force (see FIG. 3D). In the embodiment according to the present invention, when the engine braking force is preferentially distributed over the friction braking force, and the engine braking force of the allocated amount is less than the target deceleration TG, the insufficient actual braking force is obtained. This is because the engine braking force derived from the fuel cutoff control satisfies the target deceleration TG at the same time t3 to t4.
Note that at time t4 shown in FIG. 3, the target deceleration TG showing a decreasing tendency has reached the TG second threshold TGth2. In response to this, after time t4 shown in FIG. 3, the main control for generating the engine braking force is shifted from the fuel cutoff control to the shift control with downshift.

From time t4 to t5 shown in FIG. 3, the accelerator pedal 21 continues to be moderately decelerated. With this deceleration operation, the target deceleration TG gradually decreases (see FIG. 3A).
At time t4, the main control for generating the engine braking force is shifted from the fuel cutoff control to the shift control with downshift (see FIGS. 3B and 3C). From the same time t4 to t5, the engine output is maintained at a constant value by the fuel cutoff control (see FIG. 3B). The CVT gear ratio is downshifted (see FIG. 3C).
At the same time t4 to t5, the engine braking force derived from the synergistic action of the fuel cutoff control and the shift control with downshift is acting alone as the actual braking force (see FIG. 3D). In the embodiment according to the present invention, when the engine braking force is preferentially distributed over the friction braking force, and the engine braking force of the allocated amount is less than the target deceleration TG, the insufficient actual braking force is obtained. This is because, at the same time t4 to t5, the engine braking force derived from the synergistic effect of the fuel cut-off control and the shift control accompanied by the downshift satisfies the target deceleration TG.
Note that at time t5 shown in FIG. 3, the target deceleration TG showing a decreasing tendency has reached the TG third threshold TGth3. In response to this, after time t5 shown in FIG. 3, in addition to the engine braking force derived from the synergistic effect of the fuel cutoff control and the shift control with downshift, the friction braking force is acting as the actual braking force. (See FIG. 3 (d)). In the embodiment according to the present invention, when the engine braking force is preferentially distributed over the friction braking force, and the engine braking force of the allocated amount is less than the target deceleration TG, the insufficient actual braking force is obtained. This is because the engine braking force derived from the synergistic effect of the fuel cut-off control and the shift control accompanied by the downshift is less than the target deceleration TG after time t5.

At times t5 to t6 shown in FIG. 3, the accelerator pedal 21 continues to be moderately decelerated. With this deceleration operation, the target deceleration TG gradually decreases (see FIG. 3A).
After time t5, as a control for generating the actual braking force, friction braking control is executed in addition to the fuel cutoff control and the shift control with downshift (FIGS. 3B, 3C, (3)). d)). After the same time t5, the engine output is maintained at a constant value by the fuel cutoff control (see FIG. 3B). The CVT gear ratio maintains the previous shift position (see FIG. 3C). However, after the same time t5, the CVT gear ratio may be downshifted as necessary.
After time t5, as the actual braking force, a friction braking force is applied in addition to the engine braking force derived from the synergistic effect of the fuel cutoff control and the shift control accompanied by the downshift (see FIG. 3D). In the embodiment according to the present invention, when the engine braking force is preferentially distributed over the friction braking force, and the engine braking force of the allocated amount is less than the target deceleration TG, the insufficient actual braking force is obtained. This is because the engine braking force derived from the synergistic effect of the fuel cutoff control and the shift control with downshift is less than the target deceleration TG after time t5.
At time t6 shown in FIG. 3, the target deceleration TG that has shown a decreasing tendency has reached a value corresponding to the maximum deceleration. In response to this, after the time t6 shown in FIG. 3, the actual braking force maintains the value immediately before the time t6.

[Effects of the vehicle braking device 11 according to the embodiment of the present invention]
Next, the effect of the vehicle braking device 11 according to the embodiment of the present invention will be described.
The vehicle braking device 11 based on the first aspect accelerates and decelerates the vehicle 12 and a friction braking portion (friction braking mechanism) 37 that generates a friction braking force by applying a friction braking member 45 to the wheels of the vehicle 12. An accelerator pedal (acceleration / deceleration operation element) 21 in which the acceleration region and the deceleration region are set with the boundary threshold value P1 interposed in the operation range related to acceleration / deceleration, an internal combustion engine 41 mounted on the vehicle 12, and When the accelerator pedal 21 is decelerated, and a driving / braking mechanism 35 that has a continuously variable transmission (power transmission mechanism) 43 and generates a driving force and an engine braking force for the vehicle 12, a target based on the decelerating operation A target acceleration / deceleration setting unit (target deceleration setting unit) 71 that sets the deceleration TG and the actual braking force that acts on the vehicle when the accelerator pedal 21 is decelerated are used as the target acceleration / deceleration setting unit 71. Both the friction braking force related to the friction braking mechanism 37 and the engine braking force related to the driving braking mechanism 35 are distributed according to a predetermined rule so as to follow the target braking force having a magnitude based on the set target deceleration TG. Or an acceleration / deceleration control unit (brake control unit) 73 that performs braking control of the vehicle 12 using an actual braking force including an engine braking force. The acceleration / deceleration control unit 73 converts the friction braking force into an actual braking force. On the other hand, the engine braking force is preferentially distributed according to the above rules, and when the allocated amount of engine braking force is less than the target braking force, the friction braking force is distributed as the insufficient actual braking force. It was decided to adopt. The target braking force having a magnitude based on the target deceleration TG may be obtained by multiplying the target deceleration by the vehicle mass.

  According to the vehicle braking device 11 based on the first aspect, when the application of the friction braking force is assumed as the actual braking force based on the deceleration operation of the accelerator pedal 21, the situation in which the friction braking member 45 falls into a fade state. Can be suppressed.

  The vehicle braking device 11 based on the second aspect is the vehicle braking device 11 based on the first aspect, and includes an input / output unit (gradient information acquiring unit) that acquires gradient information relating to a road on which the vehicle 12 is traveling. ) 61, and the acceleration / deceleration control unit 73 occupies the ratio of the engine braking force in the actual braking force when the vehicle 12 is traveling on a downhill road compared to when the vehicle 12 is traveling on a flat road. You may employ | adopt the structure which increases.

  According to the vehicle braking device 11 based on the second aspect, when the vehicle 12 is traveling on a downhill road, the friction braking force of the actual braking force is greater than that when the vehicle 12 is traveling on a flat road. Therefore, the friction braking member 45 can be prevented from being faded.

  The vehicle braking device 11 based on the third aspect is the vehicle braking device 11 based on the second aspect, and the acceleration / deceleration control unit 73 uses the gradient information when the vehicle 12 is traveling on a downhill road. You may employ | adopt the structure which increases the ratio for which an engine braking force occupies among actual braking force, so that the grade value SL based on exceeds the predetermined gradient threshold value SLth increases.

  According to the vehicle braking device 11 based on the third aspect, the acceleration / deceleration control unit 73 increases the degree that the gradient value SL based on the gradient information exceeds the gradient threshold SLth when the vehicle 12 is traveling on a downhill road. That is, as the downhill road becomes steeper, the ratio of the engine braking force to the actual braking force is increased. Therefore, compared with the vehicle braking device 11 based on the second aspect, the frictional braking of the actual braking force is reduced. As a result of further reducing the proportion of power, the situation in which the friction braking member falls into a fade state can be further suppressed.

  The vehicle braking device 11 based on the fourth aspect is the vehicle braking device 11 based on any one of the first to third aspects, and is an input / output unit (temperature information) that acquires temperature information of the friction braking member 45. Acquisition unit) 61, and the acceleration / deceleration control unit 73, when the temperature value RT of the friction braking member 45 exceeds a predetermined temperature threshold RTth, the temperature value RT of the friction braking member 45 is equal to or lower than the temperature threshold RTth. Compared to the above, a configuration in which the ratio of the engine braking force to the actual braking force is increased may be adopted.

  According to the vehicle braking device 11 based on the fourth aspect, when the temperature value RT of the friction braking member 45 exceeds the temperature threshold RTth, the proportion of the actual braking force occupied by the friction braking force is relatively reduced. Therefore, the situation where the friction braking member 45 falls into a fade state can be suppressed.

  The vehicle braking device 11 based on the fifth aspect is the vehicle braking device 11 based on the fourth aspect, and the acceleration / deceleration control unit 73 is a degree to which the temperature value RT of the friction braking member 45 exceeds the temperature threshold RTth. A configuration may be adopted in which the proportion of the actual braking force occupied by the engine braking force increases as the value increases.

  According to the vehicle braking device 11 based on the fifth aspect, as the degree that the temperature value RT of the friction braking member 45 exceeds the temperature threshold RTth increases, the ratio of the engine braking force in the actual braking force increases. As compared with the vehicle braking device 11 based on the fourth aspect, the ratio of the friction braking force to the actual braking force is further reduced, and as a result, the situation in which the friction braking member 45 falls into a fade state is further suppressed. be able to.

  The vehicle braking device 11 based on the sixth aspect is the vehicle braking device 11 based on any one of the first to fifth aspects, and the engine braking force related to the drive braking mechanism 35 is the internal combustion engine 41. Is generated by at least one of ignition timing control for delaying the ignition timing of the engine, fuel cutoff control for cutting off the fuel supply to the internal combustion engine 41, and shift control for downshifting the continuously variable transmission 43. The deceleration control unit 73 executes the control related to at least one or a combination of ignition timing control, fuel cut-off control, and downshift transmission control, so that the engine of the magnitude allocated as the actual braking force A configuration for generating a braking force may be employed.

  According to the vehicle braking device 11 based on the sixth aspect, the acceleration / deceleration control unit 73 executes control related to at least one or a combination of ignition timing control, fuel cutoff control, and shift control. Thus, since the engine braking force having a required magnitude distributed as the actual braking force is generated, it is possible to suppress the driver from feeling uncomfortable with the generation of the engine braking force.

  The vehicle braking device 11 based on the seventh aspect is the vehicle braking device 11 based on the sixth aspect, and the magnitude and adjustment range of the engine braking force that can be generated are ignition timing control, fuel cutoff control, The acceleration / deceleration control unit 73 increases the (required) magnitude of the engine braking force allocated as the actual braking force in the order of ignition timing control, fuel cutoff control, and shift control. Alternatively, a configuration in which mainly executed control is sequentially shifted may be employed.

  According to the vehicle braking device 11 based on the seventh aspect, for example, when the vehicle 12 is traveling at a relatively high vehicle speed, in order to obtain an engine braking force of a required magnitude, the influence on the passengers in the passenger compartment is reduced. Without considering it, a case of suddenly generating engine braking force by downshift transmission control accompanied by a sudden increase in engine speed (in this case, noise caused by a sudden increase in engine speed) In comparison, a situation in which the driver feels uncomfortable with the generation of the engine braking force based on the deceleration operation of the accelerator pedal 21 can be suppressed.

[Other Embodiments]
The plurality of embodiments described above show examples of realization of the present invention. Therefore, the technical scope of the present invention should not be limitedly interpreted by these. This is because the present invention can be implemented in various forms without departing from the gist or main features thereof.

11 Vehicle braking device 12 Vehicle 21 Accelerator pedal (acceleration / deceleration operator)
35 Driving braking mechanism 37 Friction braking mechanism (friction braking part)
41 Internal combustion engine 43 Non-transmission (power transmission mechanism)
45 Friction braking member 61 Input / output unit (gradient information acquisition unit, temperature information acquisition unit)
71 Target acceleration / deceleration setting part (Target deceleration setting part)
73 Acceleration / deceleration control unit (braking control unit)
TG Target deceleration TGth1 TG first threshold TGth2 TG second threshold TGth3 TG third threshold SLth Gradient threshold RTth Temperature threshold

Claims (7)

A friction braking unit that generates a friction braking force by applying a friction braking member to a wheel of the vehicle;
An acceleration / deceleration operator that is operated when accelerating / decelerating the vehicle and in which an acceleration region and a deceleration region are set in an operation range related to the acceleration / deceleration;
A driving and braking mechanism that has an internal combustion engine and a power transmission mechanism mounted on the vehicle, and generates a driving force and an engine braking force for the vehicle;
A target deceleration setting unit that sets a target deceleration based on the deceleration operation when the acceleration / deceleration operator is decelerated;
When the acceleration / deceleration operator is decelerated, the actual braking force acting on the vehicle follows the target braking force having a magnitude based on the target deceleration set by the target deceleration setting unit. Braking that performs braking control of the vehicle by using both the friction braking force related to the friction braking unit and the engine braking force related to the drive braking mechanism, or the actual braking force consisting of the engine braking force distributed according to a predetermined rule A control unit,
The braking control unit preferentially distributes the engine braking force with respect to the friction braking force according to the rule as the actual braking force, and the engine braking force of the allocated magnitude satisfies the target braking force. If not, the vehicle braking device distributes the friction braking force as the actual braking force of the shortage. The vehicle braking device according to claim 1,
A gradient information acquisition unit for acquiring gradient information related to a road on which the vehicle is traveling;
The braking control unit increases the proportion of the actual braking force occupied by the engine braking force when the vehicle is traveling on a downhill road compared to when the vehicle is traveling on a flat road. A braking device for a vehicle characterized by the above. The vehicle braking device according to claim 2,
When the vehicle is traveling on a downhill road, the braking control unit is configured such that the engine braking force accounts for the actual braking force as the gradient value based on the gradient information exceeds a predetermined gradient threshold. The braking device for vehicles characterized by increasing. The vehicle braking device according to any one of claims 1 to 3,
A temperature information acquisition unit that acquires temperature information of the friction braking member;
When the temperature value of the friction braking member based on the temperature information exceeds a predetermined temperature threshold, the braking control unit is more effective than the case where the temperature value of the friction braking member is equal to or lower than the predetermined temperature threshold. A vehicular braking apparatus characterized by increasing a ratio of the braking force occupied by the engine braking force. The vehicle braking device according to claim 4,
The braking device for a vehicle according to claim 1, wherein the braking control unit increases a ratio of the engine braking force in the actual braking force as the temperature value of the friction braking member exceeds the temperature threshold. The vehicle braking device according to any one of claims 1 to 5,
The engine braking force related to the drive braking mechanism includes ignition timing control that delays the ignition timing of the internal combustion engine, fuel cutoff control that shuts off fuel supply to the internal combustion engine, and a transmission that the power transmission mechanism has. It is generated by at least one of the shift control to downshift,
The braking control unit executes a control related to at least one or a combination of the ignition timing control, the fuel cutoff control, and the shift control, thereby distributing the magnitude as the actual braking force. A braking device for a vehicle, which generates an engine braking force. The vehicle braking device according to claim 6,
The magnitude and adjustment range of the engine braking force that can be generated are large in the order of the ignition timing control, the fuel cutoff control, and the shift control,
The brake control unit sequentially shifts mainly executed control in the order of the ignition timing control, the fuel cutoff control, and the shift control as the magnitude of the engine braking force allocated as the actual braking force increases. Brake device for vehicles characterized by this.