JP2017178141A - Control device of vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress an unexpected restart of an engine by a simple constitution without imparting an incongruity to an occupant.SOLUTION: There is arranged brake fluid pressure detection means SN6 for detecting the fluid pressure of a brake fluid supplied to a brake force impartment part 118, an output of an engine 1 is changed on the basis of an operation amount of an accelerator pedal 120, and a traveling mode is switched to a normal traveling mode for changing the fluid pressure of the brake fluid on the basis of an operation amount of a brake pedal 111, and a following traveling mode for controlling an output of the engine and the fluid pressure of the brake fluid irrespective of the operation amount of the accelerator pedal 120 and the operation amount of the brake pedal 111. It is determined whether or not to permit an automatic stop of the engine on the basis of the fluid pressure of the brake fluid which is detected by the brake fluid pressure detection means SN6 in either of the traveling modes.SELECTED DRAWING: Figure 5

Description

  The present invention relates to an engine, an accelerator pedal, a brake pedal, a brake device, an output of the engine and a control means for controlling the brake device, and a vehicle control device capable of automatically stopping and restarting the engine. It is.

  Conventionally, a vehicle that automatically stops and restarts an engine in order to improve fuel efficiency is known. In addition, a technique is also known in which a vehicle travels following a preceding vehicle in order to improve convenience. For example, based on an operation of a driver's predetermined switch or the like, a normal travel mode in which the vehicle travels according to an operation of an accelerator pedal and a brake pedal, and a follow-up travel mode in which the vehicle travels following the preceding vehicle, There are vehicles whose travel modes can be switched.

  Here, in a vehicle that can automatically stop and restart the engine, it may be possible to further switch the traveling mode between the normal traveling mode and the following traveling mode, but simply combining these functions, The following problems occur. That is, when traveling in the follow-up traveling mode, when the preceding vehicle stops, the host vehicle also stops accordingly. As the vehicle stops, the engine is automatically stopped. However, in this case, the brake pedal is not depressed. Therefore, in this state, when the switch or the like is operated and the travel mode is switched from the follow travel mode to the normal travel mode, the engine restarts unexpectedly because the brake pedal is not depressed. There is a fear.

  On the other hand, for example, in Patent Document 1, the engine can be automatically stopped and restarted, the travel mode can be switched between the normal travel mode and the follow-up travel mode, and the travel in the normal travel mode is performed. The vehicle is configured to automatically stop the engine based on the depression operation of the brake pedal at the time, and to automatically stop the engine when the vehicle is stopped when traveling in the follow-up traveling mode without depending on the depression operation of the brake pedal. During the automatic stop, even if an operation for canceling the follow-up running mode is performed, the one that maintains the follow-up running mode is disclosed.

  According to the vehicle of this patent document 1, since the follow-up running mode is maintained while the engine is automatically stopped, the engine restarts unexpectedly in response to an operation for canceling the follow-up running mode. Can be suppressed.

JP 2014-184879 A

  However, in the vehicle of Patent Document 1, this mode is not canceled even though the occupant performs an operation to cancel the follow-up traveling mode, which gives the occupant a sense of incongruity.

  The present invention has been made in view of the above circumstances, and provides a vehicle control device that can suppress an unexpected restart of the engine with a simple configuration without giving a sense of incongruity to an occupant. Objective.

  In order to solve the above problems, the present invention includes an engine, an accelerator pedal, a brake pedal, a brake device, an output of the engine, and a control means for controlling the brake device, and automatically stops and restarts the engine. In a possible vehicle control device, the brake device receives a supply of brake fluid and applies a braking force to a wheel, and changes a hydraulic pressure of the brake fluid supplied to the braking force application unit. Possible brake fluid pressure changing means and brake fluid pressure detecting means for detecting the fluid pressure of the brake fluid supplied to the braking force applying unit, the control means based on the operation amount of the accelerator pedal A normal travel mode for changing the output of the engine and changing the hydraulic pressure of the brake fluid based on an operation amount of the brake pedal; and the accelerator The traveling mode can be switched to the following traveling mode in which the output of the engine and the hydraulic pressure of the brake fluid are changed so as to follow the vehicle ahead regardless of the amount of operation of the dull and the amount of operation of the brake pedal, In any of the normal driving mode and the following driving mode, it is determined whether or not to allow automatic engine stop based on the brake fluid pressure detected by the brake fluid pressure detecting means. (Claim 1).

  In this configuration, regardless of whether the travel mode is the normal travel mode or the follow travel mode, automatic engine stop is permitted according to the hydraulic pressure of the brake fluid. Therefore, even if the occupant performs an operation of switching the travel mode from the follow travel mode to the normal travel mode while the engine is automatically stopped, if the brake fluid pressure satisfies a predetermined condition, the travel mode The automatic engine stop can be maintained while switching to the normal running mode. Therefore, unexpected restart of the engine can be suppressed without giving the passenger a sense of incongruity. Moreover, in both the normal driving mode and the following driving mode, a common control logic that allows the engine to automatically stop according to the hydraulic pressure of the brake fluid is applied. can do.

  In the present invention, the control means is a reference value in which the brake fluid pressure detected by the brake fluid pressure detection means is set in advance in any of the normal running mode and the follow-up running mode. In the above case, it is determined that the automatic stop of the engine is permitted, and the reference value is preferably set to the same value in each traveling mode (Claim 2).

  According to this configuration, the automatic stop of the engine is permitted when the hydraulic pressure of the brake fluid exceeds a reference value regardless of the travel mode. The timing at which the stop is performed can be made substantially the same, and the uncomfortable feeling given to the occupant can be reduced more reliably.

  Also, in the present invention, the brake device is configured to connect the braking force applying unit and the brake fluid pressure changing means, and to open and close the brake fluid circuit and close the brake fluid circuit. And a control valve for holding the hydraulic pressure of the brake fluid supplied to the braking force application unit, and the control means is configured to stop the brake fluid when the host vehicle stops in a state where the follow-up running mode is being implemented. While the circuit is closed by the control valve, once the closing is performed, the closing is maintained until a predetermined condition is satisfied even when the traveling mode is switched to the normal traveling mode. Preferred (claim 3).

  According to this configuration, even when the following traveling mode is performed and the brake pedal is not depressed, the brake fluid pressure can be maintained high, and the stop state can be more reliably maintained. be able to. Furthermore, even when the driving mode is switched from the follow driving mode to the normal driving mode, the brake fluid pressure is kept high until a predetermined condition is satisfied, so the engine is automatically stopped regardless of the driving mode. Therefore, the engine can be prevented from restarting unexpectedly without causing the passenger to feel uncomfortable.

  In the above configuration, when the host vehicle is stopped in the state in which the follow-up running mode is being performed, the control unit is configured to change the brake fluid circuit after a preset reference period has elapsed since the stop of the host vehicle. It is preferably closed by the control valve (claim 4).

  In this way, when it is desired to start immediately after stopping, this start can be performed earlier.

  In the above-described configuration, the control means may be configured such that after the brake fluid circuit is once closed by the control valve, if the vehicle speed is less than a preset reference speed even if the vehicle speed increases to 0 or more, the control valve It is preferable to keep the brake fluid circuit closed according to (Claim 5).

  According to this configuration, it is possible to suppress the braking force applied to the wheels from being reduced just by slightly moving the wheels regardless of the intention of the occupant to start due to vibration or the like, thereby improving safety. .

  In the above configuration, it is preferable that the control unit cancels the follow-up running mode when the brake pedal is operated while the engine is automatically stopped (Claim 6).

  According to this configuration, the follow-up running mode can be released relatively easily by operating the brake pedal. On the other hand, in the configuration in which the follow-up running mode is easily released in this way, there is a risk that the engine will start unexpectedly when this release is performed during the automatic stop of the engine. Since the automatic stop of the engine is permitted according to the liquid pressure of the liquid, the unexpected start of the engine can be more reliably suppressed.

  Further, in the above configuration, a steering angle changing device for changing a steering angle of the wheel is provided, and the control means is configured to perform the following traveling mode when the steering angle changing device is operated during the automatic stop of the engine. Is preferably canceled (Claim 7).

  According to this configuration, the following traveling mode can be released relatively easily by operating the steering angle changing device. Here, in the configuration in which the following traveling mode is easily canceled in this way, there is a possibility that the engine may start unexpectedly by being canceled during the automatic stop of the engine, but in the present invention, as described above Since the automatic stop of the engine is permitted according to the hydraulic pressure of the brake fluid, the unexpected start of the engine can be suppressed more reliably.

  As a configuration for realizing the following traveling mode, an inter-vehicle distance detecting unit that detects a distance from a preceding vehicle is provided, and the output of the engine and the brake are based on the inter-vehicle distance detected by the inter-vehicle distance detecting unit. The structure which changes at least one with the liquid pressure of a liquid is mentioned (Claim 8).

  As described above, according to the present invention, unexpected restart of the engine can be suppressed with a simple configuration without causing the passenger to feel uncomfortable.

1 is a schematic configuration diagram of a vehicle to which a vehicle control device according to the present invention is applied. It is a schematic sectional drawing of an engine It is a control block diagram. It is the flowchart which showed the control procedure implemented in each driving mode. It is the flowchart which showed the procedure which determines whether implementation of idling stop is possible. It is the flowchart which showed the procedure which determines the operation | movement availability of an auto hold. It is the figure which showed the time change of each parameter at the time of a stop in normal driving mode. It is the figure which showed the time change of each parameter at the time of a stop in follow-up driving mode. It is the figure which showed the time change of each parameter when it switches from follow driving mode to normal driving mode at the time of a stop.

  Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

(1) Overall Configuration FIG. 1 is a schematic configuration diagram of a vehicle to which a vehicle control device according to the present invention is applied. FIG. 2 is a schematic sectional view of the engine 1. FIG. 3 is a control block diagram.

  As shown in FIG. 1, the vehicle according to the present embodiment is a vehicle driven by an engine 1 and has four wheels 4.

  As shown in FIG. 2, the engine 1 is a reciprocating engine, and a piston 14 reciprocates in the cylinder 2 as a mixture of air and fuel burns in the cylinder 2 formed in the engine body 1 a. It is supposed to be. An intake passage 20 that introduces intake air into the cylinder 2 and an exhaust passage 30 that discharges gas after combustion from the cylinder 2 are connected to the engine body 1a. The intake passage 20 is provided with a throttle valve 22 capable of changing the amount of intake air flowing into the cylinder 2, that is, the intake air amount.

  The engine body 1a is provided with an injector 11 for injecting fuel into the cylinder 2 and a spark plug 10 for igniting an air-fuel mixture in the cylinder 2 (air-fuel mixture). In addition, the engine body 1a receives an intake port 6 for introducing air supplied from the intake passage 20 into the cylinder 2, an intake valve 8 for opening and closing the intake port 6, and exhaust gas generated in the cylinder 2. An exhaust port 7 for leading to the exhaust passage 60 and an exhaust valve 9 for opening and closing the exhaust port 7 are provided.

  The intake valve 8 and the exhaust valve 9 are driven by valve mechanisms 18 and 19, respectively. In the present embodiment, the valve operating mechanism 18 of the intake valve 8 is provided with an intake opening / closing timing changing mechanism 18a that can change the opening / closing timing of the intake valve 8, and the intake valve 8 is opened / closed by the intake opening / closing timing changing mechanism 18a. By changing the timing, the amount of intake air flowing into the cylinder 2 can be changed.

  In the engine 1 configured as described above, the intake air amount is changed by changing the opening degree of the throttle valve 22 and the opening / closing timing of the intake valve 8, and the fuel amount injected from the injector 11 is changed. As a result, the output (engine torque) is changed.

  As shown in FIG. 1, the vehicle includes an accelerator pedal 120 and a brake pedal 111 that are depressed by the driver, and a steering wheel (steering angle changing device) 130 that is operated by the driver to change the steering angle of the wheel 4. And a brake device 110 are provided.

  The brake device 110 includes a wheel cylinder (braking force applying unit) 118 that is provided on each wheel 4 and applies a braking force to the wheels 4. The wheel cylinder 118 receives the supply of the brake fluid, and stops the rotation of the wheel 4 when the fluid pressure exceeds a predetermined value. Hereinafter, the hydraulic pressure of the brake fluid (the hydraulic pressure of the brake fluid supplied to the wheel cylinder 118) may be simply referred to as brake hydraulic pressure.

  The brake device 110 includes a brake booster 112 that assists the stepping force input to the brake pedal 111, and a master cylinder 113 that is connected to the brake booster 112 and generates a brake fluid pressure according to the brake stepping force. . Each wheel cylinder 118 and the master cylinder 113 are connected via brake fluid circuits 114, 114. When the brake pedal 111 is depressed, brake fluid pressure is applied from the master cylinder 113 to the wheel cylinder 118. The As shown in FIG. 1, in the present embodiment, the right wheel 4 and the left wheel 4 are individually connected to the master cylinder 113 via brake fluid circuits 114 and 114, respectively.

  The brake fluid circuits 114 and 114 are provided with a control unit 115 that controls the fluid pressure of the brake fluid in the circuit 114. Although a detailed description of the control unit 115 is omitted, the brake unit 115 is configured to be able to change the brake fluid pressure of each brake fluid circuit 114, 114 separately from the master cylinder 113, and this is changed. Hydraulic pressure pumps (brake hydraulic pressure changing means) 116 and 116 are provided. These hydraulic pumps 116 and 116 are driven by a motor (not shown) to change the brake hydraulic pressure.

  The brake device 110 of this embodiment has an auto hold function for maintaining the brake fluid pressure, and the brake fluid circuits 114 and 114 are provided with hold valves (control valves) 117 and 117 for opening and closing the brake fluid circuits 114 and 114. It has been. The hold valves 117 and 117 are disposed in the brake circuits 114 and 114 at positions closer to the wheel cylinders 118 and 118 than the master cylinder 113 and the brake unit 115. Therefore, when the brake fluid circuits 114 and 114 are closed by the hold valves 117 and 117, the brake fluid pressure of the wheel cylinder 118 (brake fluid pressure applied to the wheel cylinder 118) is changed to the master cylinder 113 or the hydraulic pump. Regardless of the driving state of 116, the value before closing is maintained. In the following, when the hold valves 117 and 117 are fully closed and the brake fluid pressure is held, it is said that the auto hold is activated.

  In the present embodiment, the two hydraulic pumps 116 and 116 are similarly controlled, and the two hold valves 117 and 117 are similarly controlled.

(2) Control (i) Overall Configuration Next, a vehicle control system according to the present embodiment will be described with reference to FIG. The vehicle is provided with a PCM 510 that is a control unit for controlling the engine and a DSC 520 that is a control unit for controlling the brake device 110, and by these, each part of the engine 1 and the brake unit 115 are controlled. Is done. As is well known, the PCM 510 and the DSC 520 are microprocessors composed of a CPU, a ROM, a RAM, an I / F, and the like. Hereinafter, the PCM 510 and the DSC 520 are collectively described as simply a controller (control means) 530.

  Information from various sensors is input to the controller 530.

  For example, the engine 1 is provided with an engine speed sensor SN1 for detecting the engine speed, an intake air amount sensor SN2 for detecting the intake air amount introduced into the cylinder 2, and the like. Further, the vehicle has an accelerator opening sensor SN3 for detecting the opening degree of the accelerator pedal 120 (the operation amount of the accelerator pedal 120, hereinafter referred to as the accelerator opening degree), and a brake for detecting whether or not the brake pedal 111 is depressed. A pedal sensor SN4, a vehicle speed sensor SN5 for detecting the vehicle speed, and the like are provided. Further, the brake device 110 is provided with a brake fluid pressure sensor (brake fluid pressure detecting means) SN6 that is provided in the brake fluid circuit 114 and detects the fluid pressure of the brake fluid in the circuit 114. The brake fluid pressure sensor SN6 is provided at a position closer to the wheel 4 than the hold valve 117, and detects the fluid pressure of the brake fluid applied to the wheel cylinder 118. Further, the vehicle is provided with a millimeter wave radar (inter-vehicle distance detecting means) SN7 for detecting the distance between the preceding vehicle and the host vehicle.

  The controller 530 is electrically connected to these sensors SN1 to SN7, and input signals from these sensors (engine speed, intake air amount, accelerator opening, brake pedal depression state, vehicle speed, brake fluid pressure, vehicle distance Accept distance). Controller 530 executes various calculations based on these input signals and controls each part of engine 1 and brake device 110.

  Specifically, the controller 530 outputs command signals to the throttle valve 22, the injector 11, the spark plug 10, the intake opening / closing timing changing mechanism 18a, the hydraulic pump 116, the hold valve 117, and the like.

(Ii) Travel Mode The vehicle according to the present embodiment has a so-called auto-cruise function, and the travel mode is divided into a normal travel mode in which the vehicle is operated by the driver and a follow-up travel in which the vehicle is automatically operated. It is possible to switch to the mode. That is, in the normal travel mode, the output (engine torque) of the engine 1 is changed based on the opening degree of the accelerator pedal 120, and the brake hydraulic pressure (applied to the wheel cylinder 118) is based on the depression amount of the brake pedal 111. In this mode, the brake fluid pressure is changed. On the other hand, in the follow-up running mode, the output of the engine 1 (engine torque) and the hydraulic pressure of the brake fluid (applied to the wheel cylinder 118) so as to follow the preceding vehicle regardless of the opening degree of the accelerator pedal 120 and the depression amount of the brake pedal 111. In this mode, the brake fluid pressure is changed.

  In the present embodiment, a switch for switching the travel mode is provided on the instrument panel or the like, and basically the travel mode is switched based on the switch operation by the driver. Specifically, a follow-up travel mode switch (follow-up travel mode SW in FIG. 3) SW1 is provided, and when the follow-up travel mode switch SW1 is turned on, the travel mode is switched to the follow-up travel mode. However, in the present embodiment, when the brake pedal 111 or the steering wheel 130 is operated during idling stop, which will be described later, it is estimated that the driver is willing to drive, and the follow-up running mode is canceled.

  The controller 530 is input with a signal from the following travel mode switch SW1. The controller 530 switches the travel mode according to the signal from the following travel mode switch SW1 and whether or not the brake pedal 111 or the steering wheel 130 is operated during idling stop, and each travel mode is realized. Thus, each part is controlled. Although illustration is omitted, the vehicle is provided with a sensor that detects the operation angle of the steering wheel 130, and a signal from this sensor is also input to the controller 530.

  The specific control content which the controller 530 implements in each driving mode is demonstrated using the flowchart of FIG.

  First, in step S1, the controller 530 reads an inter-vehicle distance, an accelerator opening, an engine speed, and the like. After step S1, the process proceeds to step S2.

  In step S2, it is determined whether or not the follow-up running mode is requested. As described above, in this embodiment, this determination is performed based on the signal from the follow-up travel mode switch SW1.

  If the determination in step S2 is yes, the process proceeds to step S3.

  In step S3, the target acceleration of the vehicle is set based on the inter-vehicle distance, the current vehicle speed, and the like. For example, when the inter-vehicle distance is increasing, the target acceleration is set to a positive value so as to approach the vehicle ahead. On the other hand, when the inter-vehicle distance is decreasing, the target acceleration is set to a negative value so as to be away from the preceding vehicle. After step S3, the process proceeds to step S4.

  In step S4, target values of engine torque and brake fluid pressure that realize the target acceleration calculated in step S3 are calculated. For example, when the target acceleration is set to a positive value, the target value of the engine torque is set to a value larger than the current engine torque. On the other hand, when the target acceleration is set to a negative value, the target value of the engine torque is set to a value smaller than the current engine torque. Further, when the target acceleration is negative and very small, The target value of the brake fluid pressure is set to a value higher than the current brake fluid pressure. After step S4, the process proceeds to step S5.

  In step S5, the hydraulic pump 116 is controlled so that the brake hydraulic pressure becomes the target value calculated in step S4. Specifically, the rotation speed of the motor that drives the hydraulic pump 116 is changed. After step S5, the process proceeds to step S6.

  In step S6, the intake air amount and the fuel amount supplied to the cylinder 2 are controlled so that the engine torque becomes the target value calculated in step S4. Specifically, the opening degree of the throttle valve 22 is changed, and the opening / closing timing of the intake valve 8 is changed by the intake opening / closing timing changing mechanism 18a. Further, the injection amount of the injector 11 is changed.

  On the other hand, if the determination in step S2 is NO and the normal travel mode is selected, the process proceeds to step S10.

  In step S10, the target acceleration of the vehicle is set based on the accelerator opening. After step S10, the process proceeds to step S11.

  In step S11, an engine torque that realizes the target acceleration set in step S10 is calculated. After step S11, the process proceeds to step S6, and the intake air amount and the fuel amount are controlled as described above.

  In the normal travel mode, the master cylinder 113 is driven according to the depression operation of the brake pedal 111, whereby the brake hydraulic pressure applied to the wheel cylinder 118 is changed.

(Iii) Idling stop The vehicle according to the present embodiment further has an idling stop function so that the engine is automatically stopped while the vehicle is stopped, and then the engine is automatically restarted. It has become.

  Specifically, when the idling stop condition is satisfied, the controller 530 stops the fuel injection of the injector 11 and stops the ignition by the spark plug 10 to stop the combustion in the cylinder, thereby stopping the engine. .

  The setting of the idling stop condition according to the present embodiment will be described with reference to FIG.

  First, the controller 530 reads the brake fluid pressure, the vehicle speed, and the like in step S11. After step S11, the process proceeds to step S12.

  In step S12, it is determined whether the vehicle speed is 0 or less. That is, in step S12, it is determined whether or not the vehicle has stopped.

  If the determination in step S12 is NO and the vehicle speed is greater than 0, the process proceeds to step S15.

  On the other hand, if the determination in step S12 is YES and the vehicle speed is 0 or less and the vehicle is stopped, the process proceeds to step S13.

  In step S13, it is determined whether the brake fluid pressure is equal to or higher than a preset reference value. This reference value is set to the minimum value of the brake fluid pressure at which the vehicle can be stopped. In step S13, it is determined whether the brake fluid pressure is a value that can maintain the vehicle at the stop.

  If the determination in step S13 is yes and the brake fluid pressure is greater than or equal to the reference value, the process proceeds to step S14.

  In step S14, idling stop is performed on the assumption that the idling stop condition is satisfied. That is, the engine is automatically stopped.

  On the other hand, if the determination in step S13 is NO and the brake fluid pressure is less than the reference value, the process proceeds to step S15.

  In step S15, it is determined whether or not the auto hold is operating, that is, whether or not the hold valves 117 and 117 are fully closed and the brake fluid pressure is maintained.

  If the determination in step S15 is NO, the process ends without performing idling stop.

  On the other hand, when the determination in step S15 is YES and the auto hold is operating, the process proceeds to step S14 and idling stop is performed.

  Thus, in the present embodiment, when the vehicle speed is 0 or less and the brake fluid pressure is greater than or equal to the reference value, the idling stop is performed assuming that the idling stop condition is satisfied. The idling stop is also performed when the auto hold is activated.

  Here, the control from step S11 to step S15 is performed regardless of whether the travel mode is the normal travel mode or the follow travel mode. Therefore, in this embodiment, the idling stop is performed if the vehicle speed is 0 or less, the brake fluid pressure is the reference value or more, or the auto hold is in operation, regardless of the travel mode.

(Iv) Auto-hold operation condition Next, the auto-hold operation start condition will be described with reference to FIG.

  First, in step S21, the controller 530 determines whether or not the travel mode is a follow-up travel mode. As described above, in this embodiment, this determination is made based on a signal from the follow-up traveling mode switch SW1.

  If the determination in step S21 is NO, the process ends. On the other hand, if the determination in step S21 is YES and the travel mode is the follow-up travel mode, the process proceeds to step S22.

  In step S22, it is determined whether the vehicle speed is 0 or less.

  If the determination in step S22 is no, the process ends. On the other hand, if the determination in step S22 is yes and the vehicle speed is 0 or less, the process proceeds to step S23.

  In step S23, it is determined whether or not a preset hold permission time (reference period) has elapsed since the vehicle speed became 0 or less. This hold permission time is set to about 3 seconds, for example.

  If the determination in step S23 is no, the process ends. On the other hand, if the determination in step S23 is YES and the hold permission time has elapsed since the vehicle speed became 0 or less, the process proceeds to step S24.

  In step S24, assuming that the auto hold operation start condition is satisfied, the auto hold operation is started. That is, the hold valves 117 and 117 are fully closed.

  As described above, in this embodiment, when the travel mode is the follow-up travel mode, the vehicle speed is 0 or less, and the hold permission time elapses after the vehicle speed becomes 0 or less, the auto hold operation is started. . In the follow-up running mode, the brake fluid pressure is increased when the vehicle is stopped to reduce the vehicle speed to 0 or less, and after the hold permission time has elapsed, the brake fluid pressure is increased to a high value that is substantially higher than the reference value. ing.

  On the other hand, in the present embodiment, when the auto hold is in operation, regardless of whether the travel mode is the follow travel mode or the normal travel mode, and even if the vehicle speed is greater than 0, the value is If it is less than the hold permission speed (reference speed), auto hold is maintained. The hold permission speed is a very small speed at which it can be considered that the vehicle is almost stopped, and is set in advance by experiments or the like. For example, the hold permission speed is set to a value of about 3 km / h. In other words, in the present embodiment, once the auto hold is activated, the auto hold operation is maintained regardless of the travel mode and even when the vehicle speed is slightly higher than zero.

  The auto hold is canceled when the vehicle speed becomes equal to or higher than the hold permission speed, the accelerator pedal 120 is operated (in the normal travel mode), or the engine torque increases (in the follow travel mode). .

(V) Engine restart Conditions for restarting the engine will be briefly described.

  In the present embodiment, in the normal running mode, the engine is restarted when the depression operation of the brake pedal 111 is released or the depression operation of the accelerator pedal 120 is performed during idling stop.

  On the other hand, in the follow-up running mode, the engine is restarted when it is necessary to start the vehicle to follow the preceding vehicle due to the fact that the preceding vehicle has started. Specifically, the engine is restarted when the target acceleration of the vehicle calculated in step S3 of the flowchart of FIG.

(3) Operation, etc. In this embodiment, the time change of each parameter at the time of stopping in the normal travel mode is shown in FIG. Each graph of FIG. 7 shows, in order from the top, a travel mode flag indicating a travel mode, a brake depression amount that is a depression amount of the brake pedal 111, an accelerator opening, a vehicle speed, an engine speed, a brake fluid pressure, and an idling stop implementation state. The change with time of the IS flag representing is shown. The travel mode flag indicates that the normal travel mode is being implemented when the value is 0, and the follow-up travel mode is being implemented when the value is 1. Further, when the value of the IS flag is 0, it indicates that idling stop is not being performed, and when the value is 1, it indicates that idling stop is being performed.

  As shown in FIG. 7, when the accelerator opening is set to 0 at time t <b> 1 and the depression of the brake pedal 111 is started at the same time and the depression amount is increased, according to the depression amount of the brake pedal 111. As a result, the brake fluid pressure increases. Along with this, the engine speed and the vehicle speed are reduced. Thereafter, at time t2, the vehicle speed becomes 0, and the engine speed becomes the idle speed. When the brake fluid pressure becomes equal to or higher than the reference value at time t3 in the state where the vehicle speed is 0 as described above, the IS flag is set to 1 and the idling stop is performed to stop the engine.

  As described above, in the present embodiment, in the normal traveling mode, the idling stop is performed when the conditions that the vehicle speed is 0 or less and the brake fluid pressure is the reference value or more are satisfied.

  Thereafter, the engine is restarted by releasing the depression of the brake pedal 111 at time t4. Accordingly, at time t4, the idling stop is stopped and the brake fluid pressure is reduced. Further, when the accelerator pedal 120 is depressed at time t5 and the accelerator opening increases, the engine torque is increased accordingly, and the engine speed and the vehicle speed increase.

  Next, FIG. 8 shows the time change of each parameter when the vehicle is stopped in the follow-up running mode. In FIG. 8, in addition to each graph shown in FIG. 7, an auto hold flag is additionally shown. The auto hold flag is a parameter indicating that auto hold is not operating when the value is 0, and that auto hold is being performed when the value is 1.

  As shown in FIG. 8, in the follow-up running mode, regardless of the depression amounts of the accelerator pedal 120 and the brake pedal 111 (in the example shown in FIG. 8, these pedals 111 and 112 are not depressed), at time t11. When the preceding vehicle stops, the brake fluid pressure is increased and the engine torque is reduced accordingly, whereby the engine speed and the vehicle speed are reduced. Thereafter, at time t12, the vehicle speed becomes 0, and the engine speed becomes the idle speed.

  In the follow-up running mode, as in the normal running mode shown in FIG. 7, the idling stop is performed at time t13 when the brake fluid pressure becomes equal to or higher than the reference value when the vehicle speed is 0, and the engine is stopped. The

  Thus, in this embodiment, even in the follow-up running mode, the idling stop is performed when the conditions that the vehicle speed is 0 or less and the brake fluid pressure is the reference value or more are satisfied.

  Further, in the present embodiment, the auto hold is activated at time t14 when the hold permission time has elapsed from time t12 when the vehicle speed becomes 0 or less, and the brake fluid pressure is kept high.

  Here, in the present embodiment, as described above, after the auto-hold is once operated, the auto-hold operation is maintained even if the vehicle speed is 0 or more and the vehicle speed is less than the hold permission speed. . Therefore, as shown in FIG. 8, at the time t15, even when the occupant moves in the vehicle during idling stop, the wheel 4 rotates and the vehicle speed becomes higher than 0. If so, the auto hold operation is maintained.

  Thereafter, when the target acceleration of the vehicle increases with the start of the preceding vehicle at time t16, the idling stop is stopped and the engine is restarted accordingly, and the vehicle starts. At this time, the auto-hold operation is stopped by increasing the engine torque, and the brake fluid pressure is reduced.

  FIG. 8 shows a case where idling is stopped in response to the brake fluid pressure being equal to or higher than the reference value at time t13 before the auto hold is activated at time t14. The idling stop may be performed after the value becomes equal to or greater than the value and the auto hold is activated.

  Next, FIG. 9 shows changes with time of each parameter when the steering wheel 130 is operated after the vehicle is stopped during the follow-up running mode and idling stop is realized.

  In the example of FIG. 9, as in the example of FIG. 8, the brake fluid pressure becomes equal to or higher than the reference value at time t <b> 13 and idling stop is started, and auto hold is activated at time t <b> 14. On the other hand, in the example of FIG. 9, the traveling mode is switched to the normal traveling mode as the steering wheel 130 is operated at time t25.

  Here, as described above, in the present embodiment, after the auto hold is once activated, the vehicle speed becomes equal to or higher than the hold permission speed, or the accelerator pedal 120 is operated or the engine torque increases. Auto hold is not canceled. Therefore, the auto hold operation is maintained even when the travel mode is switched to the normal travel mode at time t25.

  Therefore, although the brake pedal 111 is not depressed in the normal travel mode, the brake fluid pressure is maintained at a higher value than the reference value after time t25, and the idling stop is continued.

  After time t25, when the accelerator pedal 120 is depressed at time t26, the auto hold operation is released, the brake fluid pressure is reduced, and the idling stop is stopped. Thereafter, as the accelerator opening increases, the engine torque increases and the engine speed and the vehicle speed increase.

  As described above, in the vehicle control device according to the present embodiment, whether or not the hydraulic pressure of the brake fluid is equal to or higher than the reference value regardless of whether the travel mode is the normal travel mode or the follow travel mode. Alternatively, idling stop is permitted depending on whether or not the auto hold is operating. That is, in any travel mode, whether or not the idling stop execution condition is satisfied is determined by the common control procedure shown in FIG. Therefore, it is not necessary to construct an individual control procedure for each travel mode, and the configuration of the control program and the like can be simplified.

  In particular, in the above embodiment, the reference value for comparing the brake fluid pressure is the same value regardless of the travel mode. Therefore, the configuration can be simplified more reliably. In addition, this makes it possible to make the time from when the vehicle stops to when the idling stop is started substantially the same in the normal travel mode and the follow-up travel mode. That is, the time from time t1 to time t3 in FIG. 7 and the time from time t11 to time t13 in FIG. 8 can be made substantially the same. Therefore, it can suppress that a passenger | crew feels uncomfortable with these time being different.

  Moreover, in the present embodiment, as shown in FIG. 9, even when the traveling mode is switched from the follow traveling mode to the normal traveling mode during idling stop, the traveling mode is changed to the normal traveling mode when the brake hydraulic pressure is high. The idling stop can be maintained while switching to. Accordingly, it is possible to prevent the engine from being unexpectedly restarted due to the switching of the traveling mode, and it is possible to switch the traveling mode in accordance with the intention of the occupant.

  In particular, as described above, when the traveling mode is switched from the follow-up traveling mode to the normal traveling mode by operating the steering wheel 130 or the brake pedal 111 during idling stop, an expectation is associated with the switching of the traveling mode. It is possible to facilitate the switching of the running mode while suppressing the restart of the unnecessary engine, and the convenience is improved.

  Further, in the present embodiment, the brake device 110 is provided with a hold valve 117, and when the vehicle stops when the follow-up running mode is performed, the auto hold is activated and the brake fluid pressure is maintained high. Therefore, even when the following travel mode is being implemented and the brake pedal 111 is not depressed, the brake fluid pressure can be maintained high and the vehicle can be stopped more reliably.

  Further, in the present embodiment, once the auto hold is activated, the auto hold is maintained until the vehicle speed becomes equal to or higher than the hold permission speed, the accelerator pedal 120 is operated, or the engine torque increases. Therefore, even if the drive mode is switched from the follow-up drive mode to the normal drive mode during idling stop, it is possible to maintain the idling stop by increasing the brake fluid pressure, and more reliably without causing an uncomfortable feeling to the passenger. The engine restart can be suppressed.

(4) Modification In the above embodiment, when the vehicle speed is 0 or less, it is determined that the idling stop condition is satisfied when the brake fluid pressure is equal to or higher than the reference value, or when the auto hold is activated. The case where the stop is executed has been explained, but the determination whether or not the auto hold is operating is omitted, and it is determined whether or not the idling stop condition is satisfied based on whether or not the brake fluid pressure is equal to or higher than the reference value. May be.

  In addition, the reference value for determining success or failure of the idling stop condition may be a value that differs for each travel mode. However, if the reference value is made common regardless of the driving mode, the configuration can be further simplified as described above, and the start timing of the idling stop can be set substantially at the same time regardless of the driving mode. .

  In the embodiment, the case where the auto hold is activated after the hold permission time elapses after the vehicle stops is described. However, after the vehicle stops, the brake fluid pressure becomes high regardless of the elapsed time (for example, the reference value). The auto hold may be activated at the time when the above is reached. However, if it takes time to open and close the hold valve 117 and the brake fluid pressure does not drop immediately even after the auto hold operation is released, the vehicle may start more slowly than the passenger intends. On the other hand, if comprised as mentioned above, in the case where it is desired to start immediately after the vehicle stops, it is possible to suppress the delay in starting, and the convenience can be improved.

  Further, the condition for switching from the follow-up running mode to the normal running mode during idling stop is not limited to the time when the brake pedal 111 is operated or the steering wheel 130 is operated. However, if the driving mode is switched by these operations, the driving mode can be more easily switched, and convenience is enhanced.

1 Engine 110 Brake Device 111 Brake Pedal 114 Brake Fluid Circuit 116 Fluid Pressure Pump (Brake Fluid Pressure Changing Means)
117 Hold valve (control valve)
118 Wheel cylinder (braking force applying part)
120 accelerator pedal 530 controller (control means)
SN6 Brake fluid pressure sensor (brake fluid pressure detection means)

Claims (8)

In a vehicle control device having an engine, an accelerator pedal, a brake pedal, a brake device, a control means for controlling the output of the engine and the brake device, and capable of automatically stopping and restarting the engine,
The brake device includes a braking force applying unit that receives a supply of brake fluid and applies a braking force to the wheels, and a brake fluid pressure changing unit that can change a hydraulic pressure of the brake fluid supplied to the braking force applying unit. A brake fluid pressure detecting means for detecting a fluid pressure of the brake fluid supplied to the braking force applying unit,
The control means includes
A normal travel mode in which the output of the engine is changed based on the operation amount of the accelerator pedal, and the hydraulic pressure of the brake fluid is changed based on the operation amount of the brake pedal, the operation amount of the accelerator pedal, and the The travel mode can be switched to a follow travel mode that changes the output of the engine and the hydraulic pressure of the brake fluid so as to follow the vehicle ahead regardless of the amount of operation of the brake pedal,
In any of the normal driving mode and the following driving mode, it is determined whether or not to allow automatic engine stop based on the brake fluid pressure detected by the brake fluid pressure detecting means. A control apparatus for a vehicle. The vehicle control device according to claim 1,
In any of the normal travel mode and the follow-up travel mode, the control means is configured such that the brake fluid pressure detected by the brake fluid pressure detection means is equal to or higher than a preset reference value. The vehicle control device is characterized in that it is determined that the automatic stop of the engine is permitted, and the reference value is set to the same value in each travel mode. The vehicle control device according to claim 1 or 2,
The brake device includes: a brake fluid circuit that connects the braking force application unit and the brake fluid pressure changing unit; and the brake fluid circuit that is capable of opening and closing the brake fluid circuit and closing the brake fluid circuit. A control valve for holding the hydraulic pressure of the brake fluid being supplied to
The control means closes the brake fluid circuit with the control valve when the host vehicle stops in a state where the follow-up running mode is being implemented, and once the closure is made, the running mode is set to the normal running. Even when the mode is switched, the vehicle control device is characterized in that the closure is maintained until a predetermined condition is satisfied. The vehicle control device according to claim 3,
In a case where the host vehicle is stopped in the state where the follow-up running mode is being implemented, the control means causes the brake fluid circuit to be moved by the control valve after a preset reference period has elapsed since the stop of the host vehicle. A control device for a vehicle, wherein the control device is closed. The vehicle control device according to claim 3 or 4,
After the brake fluid circuit is once closed by the control valve, the control means is configured to control the brake fluid by the control valve if the vehicle speed is less than a preset reference speed even if the vehicle speed increases to 0 or more. A control device for a vehicle, characterized by maintaining circuit closure. In the vehicle control device according to any one of claims 1 to 5,
The vehicle control apparatus according to claim 1, wherein the control means cancels the follow-up running mode when the brake pedal is operated while the engine is automatically stopped. In the control apparatus of the vehicle in any one of Claims 1-6,
A steering angle changing device for changing the steering angle of the wheel;
The vehicle control apparatus according to claim 1, wherein the control means cancels the follow-up running mode when the steering angle changing device is operated while the engine is automatically stopped. In the vehicle control device according to any one of claims 1 to 7,
An inter-vehicle distance detecting means for detecting the distance of the host vehicle to the preceding vehicle,
The control means changes at least one of the output of the engine and the hydraulic pressure of the brake fluid based on the inter-vehicle distance detected by the inter-vehicle distance detection means when the follow-up running mode is implemented. A control apparatus for a vehicle.

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