JP2020084960A - vehicle - Google Patents

Abstract

To provide a vehicle capable of suppressing occurrence of noise of a brake body occurring in stopping idling of an engine.SOLUTION: A vehicle 1 has driving wheels on which driving force of an engine 80 acts when the vehicle 1 is stopped. The vehicle 1 has a determination unit 30, a hydraulic pressure control unit 40, and a stop control unit 50. When an idling-stop condition other than a brake fluid pressure condition of the drive wheels is satisfied when the vehicle 1 is stopped and the engine 80 is idling, the determination unit 30 determines whether or not braking force of the drive wheels is lower than the driving force of the drive wheels based on the brake fluid pressure of the drive wheels. When the determination unit 30 determines that the braking force of the driving wheels is lower than the driving force, the hydraulic pressure control unit 40 increases the brake hydraulic pressure of the drive wheels so that the braking force of the drive wheels becomes equal to or larger than the driving force of the drive wheels. When the braking force of the drive wheels exceeds the driving force of the drive wheels, the stop control unit 50 stops idling of the engine 80.SELECTED DRAWING: Figure 1

Description

The present invention relates to a vehicle that stops engine idling after the vehicle stops.

BACKGROUND ART As a vehicle that stops engine idling after the vehicle has stopped, there is known a vehicle including an automatic engine stop/restart device for the vehicle of Patent Document 1. In the vehicle automatic engine stop/automatic restart device of Patent Document 1, when the engine is automatically restarted, the braking force release timing is made different between the front wheels and the rear wheels to prevent a sudden decrease in the braking force. , I try not to make the driver feel uncomfortable.

JP, 2003-260960, A

It is desired to suppress the generation of abnormal noise of the brake main body which occurs when the idling of the engine is stopped after the vehicle is stopped.

One of the objects of the present invention is to provide a vehicle capable of suppressing the generation of abnormal noise of the brake main body that occurs when the engine idling is stopped.

The present inventors investigated the cause of generation of the abnormal noise. As a result, it was found that the generation of abnormal noise was caused by the following phenomena (a) to (d).

(A) When the vehicle is stopped and the engine is idling, the braking force of the driving wheels is smaller than the driving force of the engine that acts on the driving wheels.
(B) Since the driving force of the driving wheel is smaller than the braking force of the driving wheel, a force is generated between the driving wheel and the driven wheel, and the suspension or the like is bent.
(C) When the engine idling is stopped while the suspension or the like is flexed, the flexure is released all at once.
(D) When the flexure is released, the friction material of the brake main body that applies the braking force to the drive wheel and the mating material (the disc rotor or the brake drum) come into sliding contact with each other.

The driving force of the engine that acts on the drive wheels when the vehicle is stopped and the engine is idling is the force associated with the creep phenomenon that causes the vehicle to move forward even if the driver of the vehicle does not press the accelerator pedal. The vehicle can be stopped when the total braking force of the front wheels and the rear wheels exceeds a threshold value for stopping the vehicle only by the braking force of the front wheels or a threshold value for stopping the vehicle by only the braking force of the rear wheels. The threshold for stopping the vehicle only by the braking force of the front wheels and the threshold for stopping the vehicle only by the braking force of the rear wheels are the same. When the vehicle stops when the total braking force of the front wheels and the rear wheels exceeds a threshold value at which the vehicle can be stopped only by the braking force of the front wheels (rear wheels), the braking force of the driving wheels may be less than the driving force of the driving wheels. is there. That is, the braking force of the driving wheels may fall below a threshold value at which the vehicle is stopped only by the braking force of the driving wheels. In this case, the difference between the braking force of the driving wheel and the driving force of the driving wheel acts on the driving wheel as torque in the forward (rear) direction of the driving wheel. The torque in the forward (reverse) direction causes the suspension or the like to bend due to the rotation of the wheels being stopped. If the idling stops when the suspension or the like is flexed, the driving force of the drive wheels becomes zero, and the flexure of the suspension or the like is released all at once. The reaction in which the flexure is released causes a torque in the rearward (forward) direction of the drive wheel to act on the drive wheel. At that time, the friction material of the brake main body, which applies the braking force to the drive wheels, and the mating material are in sliding contact with each other. Friction noise is generated along with this sliding contact.

This phenomenon occurs regardless of whether the vehicle drive system is front-wheel drive, rear-wheel drive, or four-wheel drive (4WD). Especially, when the drive system is rear wheel drive, the above-mentioned abnormal noise is likely to occur. This is because the brakes of the front wheels and the rear wheels of the vehicle are generally designed so that the braking force of the front wheels is higher than the braking force of the rear wheels. In other words, the total braking force of the front wheels and the rear wheels is higher than the threshold value for stopping the vehicle only by the braking force of the rear wheels, compared to the case where the braking force of the front wheels exceeds the threshold value for stopping the vehicle. Because it will grow.

The inventors of the present invention have found the cause of the above-mentioned abnormal noise, and when an idling stop condition other than the brake fluid pressure condition of the drive wheels is satisfied when the vehicle is stopped and the engine is idling, the following (1) or (2) It was found that the occurrence of the abnormal noise can be suppressed by satisfying the condition of.
(1) When the braking force of the driving wheels exceeds the driving force of the driving wheels (2) The braking force of the driving wheels becomes zero, and the braking force of the driven wheels is a threshold value at which the vehicle can be stopped only by the braking force of the driven wheels. When it exceeds, the present invention is based on these findings.

A first vehicle according to an aspect of the present invention is
A vehicle having driving wheels to which a driving force of an engine acts when the vehicle is stopped,
When an idling stop condition other than the brake fluid pressure condition of the drive wheel is satisfied when the vehicle is stopped and the engine is idling, the braking force of the drive wheel is determined based on the brake fluid pressure of the drive wheel. And a determination unit that determines whether or not
When the determination unit determines that the braking force of the drive wheel is lower, a hydraulic pressure control unit that increases the brake hydraulic pressure of the drive wheel so that the braking force of the drive wheel becomes equal to or greater than the drive force of the drive wheel. When,
A stop control unit that stops idling of the engine when the braking force of the drive wheels becomes equal to or greater than the drive force of the drive wheels.

A second vehicle according to an aspect of the present invention is
A vehicle having driving wheels to which a driving force of an engine acts when the vehicle is stopped,
When an idling stop condition other than the brake fluid pressure condition of the drive wheel is satisfied when the vehicle is stopped and the engine is idling, the braking force of the drive wheel is determined based on the brake fluid pressure of the drive wheel. And a determination unit that determines whether or not
When the determination unit determines that the braking force of the driving wheel is lower, the brake fluid pressure of the driving wheel is reduced so that the braking force of the driving wheel becomes zero, and the braking force of the driven wheel is reduced. A hydraulic pressure control unit for increasing the brake hydraulic pressure of the driven wheels so as to be equal to or more than a threshold value at which the vehicle can be stopped only by the braking force of the driving wheels,
A vehicle comprising: a stop control unit that stops idling of the engine when the braking force of the driving wheels becomes zero and the braking force of the driven wheels becomes equal to or more than the threshold value.

The first and second vehicles can suppress the generation of abnormal noise of the brake body that occurs when the engine idling is stopped.

In the first vehicle, the braking force of the drive wheels can be increased more than the drive force of the drive wheels by the hydraulic pressure control unit before the idling of the engine is stopped. That is, the braking force of the driving wheels can be increased to a value equal to or higher than a threshold value at which the vehicle can be stopped only by the braking force of the driving wheels. Therefore, it is possible to eliminate the flexure of the suspension due to the torque in the forward (backward) direction due to the driving force of the drive wheels. Therefore, it is possible to prevent sliding contact between the friction material and the mating material in the brake main body of the drive wheel due to the torque in the backward (forward) direction of the drive wheel when idling is stopped.

In the second vehicle, the braking force of the driving wheels can be made zero by the hydraulic pressure control unit before the idling of the engine is stopped, so that the friction material of the brake main body of the driving wheels and the mating material can be separated from each other. Therefore, when idling is stopped, the friction material of the brake main body of the drive wheel does not come into sliding contact with the mating material. Then, before the idling of the engine is stopped, the hydraulic pressure control unit increases the braking force of the driven wheels to a value equal to or higher than a threshold value at which the vehicle is stopped only by the braking force of the driven wheels. Therefore, even if idling is stopped by setting the braking force of the driving wheels to zero, the vehicle can be kept stopped.

FIG. 1 is a configuration diagram showing an outline of a vehicle according to the first and second embodiments. FIG. 2 is a graph showing the relationship between the braking force of the front wheels and the rear wheels of the vehicle according to the first and second embodiments and the reference example 1. FIG. 3 is a flowchart showing a control procedure of idling stop when the vehicle drive system according to the first embodiment is rear wheel drive (4WD). FIG. 4 is a flowchart showing a control procedure of the idling stop system when the vehicle drive system according to the second embodiment is front wheel drive. FIG. 5 is a schematic diagram of a vehicle according to the first reference example. FIG. 6 is a flowchart showing a control procedure of idling stop of the vehicle according to the first reference example.

Embodiments 1 and 2 of the vehicle of the present invention will be described below. The same reference numerals in the drawings indicate the same names.

<<Embodiment 1>>
〔vehicle〕
The vehicle 1 according to the first embodiment will be described with reference to FIGS. 1 to 3. The vehicle 1 according to the first embodiment has drive wheels on which the driving force of the engine 80 acts when the vehicle 1 is stopped and the engine 80 is idling (FIG. 1 ). One of the characteristics of the vehicle 1 according to the first embodiment is that when the idling stop (IDS) condition is satisfied when the vehicle 1 is stopped and the engine 80 is idling, if the braking force of the driving wheels is less than the driving force of the driving wheels. The point is that an idling stop system (IDSS) 20 is provided to stop the idling of the engine 80 after increasing the braking force of the driving wheels to a level greater than that of the driving wheels. Hereinafter, first, the outline of the vehicle 1 will be described, and then the IDSS 20 will be described.

[Overview]
The vehicle 1 has drive wheels on which the driving force of the engine 80 acts when the vehicle 1 is stopped and the engine 80 is idling. The driving force is a force associated with a creep phenomenon that causes the vehicle 1 to move forward even if the driver of the vehicle 1 does not press the accelerator pedal. That is, although not shown, the transmission system of the vehicle 1 includes an AT (automatic transmission) having a torque converter and a CVT (continuously variable transmission) having a torque converter. The magnitude of the driving force varies depending on whether the road surface on which the vehicle 1 stops is a flat road or an inclined road (uphill or downhill). Specifically, the driving force increases in the order of the driving force when stopped on an uphill, the driving force when stopped on a flat road, and the driving force when stopped on a downhill.

The drive wheels differ depending on the drive system of the vehicle 1. The drive system may be front wheel drive, rear wheel drive, or 4WD. When the drive system is front-wheel drive, the front wheels 61 are drive wheels and the rear wheels 62 are driven wheels. Similarly, in the case of rear wheel drive, the rear wheel 62 is the driving wheel and the front wheel 61 is the driven wheel. In the case of 4WD, both the front wheels 61 and the rear wheels 62 are drive wheels. The front wheels 61 and the rear wheels 62 are braked by a brake system.

The brake system applies a brake fluid pressure (hydraulic pressure) proportional to the depression force of the brake pedal 73 by the driver to the brake main bodies 71 and 72 of the front wheels 61 and the rear wheels 62 to generate a braking force. The brake bodies 71 and 72 may be disc brakes or drum brakes. The brake system of this example is a hydraulic (hydraulic) brake.

In the hydraulic brake, the brake pedal 73 and the brake bodies 71 and 72 of the front wheel 61 and the rear wheel 62 are mechanically connected to each other. The brake fluid pressure is generated by the master cylinder 74. The brake fluid pressure generated in the master cylinder 74 is distributed to each of the brake bodies 71 and 72 of the front wheels 61 and the rear wheels 62 via the brake actuator 77. The brake actuator 77 raises or lowers the brake fluid pressure from the master cylinder 74 so that the braking force of the front wheels 61 and the rear wheels 62 becomes a predetermined distribution. The distribution of the braking force to the front wheels 61 and the rear wheels 62 is determined depending on the type of the vehicle 1. Generally, the distribution of the braking force to the front wheels 61 and the rear wheels 62 is adjusted so that the brake main body 71 of the front wheels 61 is larger than the brake main body 72 of the rear wheels 62. The brake actuator 77 can be controlled by the hydraulic pressure control unit 40 described later. The hydraulic brake is normally provided with a booster device 76 interposed between the brake pedal 73 and the master cylinder 74 to assist the pedaling force of the brake pedal 73.

The brake system may be brake by wire. The brake-by-wire is different from the hydraulic brake in that the brake pedal 73 and the brake bodies 71 and 72 are not mechanically connected but electrically connected. The brake-by-wire includes, in place of the master cylinder 74, a sensor that detects the depression force of the brake pedal 73 and an electric hydraulic (hydraulic) pump that generates a brake hydraulic pressure based on the detection result of the sensor.

[Idling stop system]
The IDSS 20 of this example includes a determination unit 30, a hydraulic pressure control unit 40, and a stop control unit 50. The IDS-ECU (electronic control unit) 21 can be used as the determination unit 30, the hydraulic pressure control unit 40, and the stop control unit 50.

(Judgment part)
When the IDS condition other than the brake fluid pressure condition of the drive wheel is satisfied when the vehicle 1 is stopped and the engine 80 is idling, the determination unit 30 determines that the braking force of the drive wheel is based on the brake fluid pressure of the drive wheel. It is determined whether the driving force is lower than the driving force (lower than the driving force).

To satisfy the IDS condition, for example, the battery capacity is sufficient, the temperature of the cooling water of the engine 80 is not too low, and the difference between the set temperature of the air conditioner and the temperature inside the vehicle compartment is small. These conditions can be detected by various sensors.

The brake fluid pressure of the drive wheels can be detected by the brake fluid pressure sensor 75. The brake fluid pressure sensor 75 is provided, for example, downstream of the brake actuator 77. That is, the brake fluid pressure sensor 75 can detect the brake fluid pressure applied to each of the brake bodies 71 and 72 of the front wheel 61 and the rear wheel 62. The braking force of the driving wheels is proportional to the magnitude of the brake fluid pressure of the driving wheels.

The driving force of the driving wheels is obtained by previously mapping and storing the driving force corresponding to the stopped state (tilt) of the vehicle 1 and comparing the detected stopped state (tilt) of the vehicle 1 with the map. be able to. The stopped state (tilt) of the vehicle 1 can be determined by an acceleration sensor.

(Hydraulic pressure controller)
When the determination unit 30 determines that the braking force of the driving wheels is less than the driving force of the driving wheels, the hydraulic pressure control unit 40 adjusts the braking fluid pressure of the driving wheels so that the braking force of the driving wheels becomes equal to or greater than the driving force. Boost. The brake fluid pressure can be increased by controlling the operation of the brake actuator 77 by the fluid pressure control unit 40.

(Stop control unit)
The stop control unit 50 stops the idling of the engine 80 when the hydraulic pressure control unit 40 increases the brake hydraulic pressure of the drive wheels so that the braking force of the drive wheels becomes equal to or greater than the drive force. Further, the stop control unit 50 stops the idling of the engine 80 when the determination unit 30 determines that the braking force of the driving wheels satisfies the driving force of the driving wheels or more.

(Control procedure)
The control procedure of the IDSS 20 of the vehicle 1 according to the first embodiment will be described for each drive system based on the graph of FIG. 2 and the flowchart of FIG. The graph of FIG. 2 shows the relationship between the braking force of the front wheels 61 and the braking force of the rear wheels 62 required to stop the vehicle 1. The horizontal axis of the graph represents the braking force of the front wheels 61, and the vertical axis represents the braking force of the rear wheels 62. The threshold value of the total braking force of the front wheels 61 and the rear wheels 62 required to stop the vehicle 1 is indicated by the line segment α. The line segment α depends on the vehicle type. The line segment β indicates the total braking force of the front wheels 61 and the rear wheels 62 based on the total value of the brake fluid pressures of the front wheels 61 and the rear wheels 62 measured by the brake fluid pressure sensor 75. When the line segment β (the total braking force of the front wheels 61 and the rear wheels 62) reaches the area on the right side of the line segment α, the vehicle 1 stops. The slope of the line segment β is determined according to the distribution of the braking force to the front wheels 61 and the rear wheels 62. Generally, since the braking force of the front wheels 61 is larger than the braking force of the rear wheels 62, the slope of the line segment β is 1 or less. The line segment α intersects both the horizontal axis and the vertical axis, and the intersection of the line segment α and the horizontal axis is a threshold value x1 at which the vehicle 1 can be stopped only by the braking force of the front wheels 61, and the line segment α and the vertical axis. The intersection with the axis is a threshold value y1 at which the vehicle 1 can be stopped only by the braking force of the rear wheel 62. The threshold value x1 and the threshold value y1 are the same. The flowchart of FIG. 3 shows a control procedure of the IDSS 20 when the drive system is rear wheel drive (4WD).

When the IDS conditions other than the brake fluid pressure conditions for the driving wheels are satisfied when the vehicle 1 is stopped and idling, the IDS control is started. That is, based on the measurement result of the brake fluid pressure sensor 75 when the driver of the vehicle 1 depresses the brake pedal 73, the total braking force of the front wheel 61 and the rear wheel 62 (the line based on the brake fluid pressure of the front wheel 61 and the rear wheel 62) is calculated. When it is determined that the segment β) is at or above the intersection with the line segment α, the control of the IDS is started.

<When the drive system is rear-wheel drive>
Based on the measurement result of the brake fluid pressure sensor 75, the determination unit 30 determines whether the braking force based on the brake fluid pressure of the rear wheel 62, which is the driving wheel, is lower than the driving force of the rear wheel 62. That is, it is determined whether the braking force of the rear wheel 62 is less than the threshold value y1 (step S11).

When the condition of step S11 is satisfied, the hydraulic pressure control unit 40 operates the brake actuator 77 to increase the brake hydraulic pressure of the brake main body 72 of the rear wheel 62 so that the braking force of the rear wheel 62 becomes equal to or greater than the threshold value y1. (Step S12).

Subsequently, the stop control unit 50 stops idling of the engine 80 (IDS) (step S13). Then, this control ends.

When the condition of step S11 is not satisfied, that is, when the braking force of the rear wheel 62 satisfies the threshold value y1 or more (the driving force of the rear wheel 62 or more), the control ends through step S13.

<When the drive system is front-wheel drive>
In the control procedure of the IDSS 20 in the front wheel drive, the rear wheel 62 in the control procedure of the IDSS 20 in the rear wheel drive may be read as the front wheel 61, the threshold value y1 as the threshold value x1, and the brake body 72 as the brake body 71.

<When the drive system is 4WD>
The control procedure of the IDSS 20 in 4WD is the same as the control procedure of the IDSS 20 in the rear wheel drive. This is because if the braking force of the rear wheel 62 satisfies the threshold value y1 or more, the braking force of the front wheel 61 satisfies x1 or more. Therefore, regardless of the magnitude relationship between the driving force of the front wheels 61 and the driving force of the rear wheels 62, sliding contact between the friction material and the mating material in the brake body of the driving wheel can be prevented. When the driving force acts only on the front wheels 61 when the vehicle is stopped in 4WD, the same control procedure as the control procedure of the IDSS 20 in front wheel drive may be performed.

[Action effect]
The vehicle 1 according to the first embodiment can suppress the generation of abnormal noise of the brake body that occurs when the engine 80 stops idling. Before the idling of the engine 80 is stopped, the braking force of the drive wheels can be increased to a threshold value or more by the hydraulic pressure control unit 40, so that it is possible to prevent sliding contact between the friction material and the mating material in the brake body of the drive wheels when the idling is stopped. Because.

<<Embodiment 2>>
〔vehicle〕
A vehicle 1 according to a second embodiment will be described with reference to FIGS. 1, 2, and 4. One of the characteristics of the vehicle 1 according to the second embodiment is that if the braking force of the driving wheels is lower than the driving force of the driving wheels when the IDS condition is satisfied when the vehicle 1 is stopped and the engine 80 is idling, The point is that the IDSS 20 is provided to stop idling of the engine 80 after the braking force is set to zero and the braking force of the driven wheels is increased to a specific threshold value or more. The drive type of the vehicle 1 of this example is, for example, front wheel drive. Since the outline of the vehicle 1 of this example is the same as that of the first embodiment, the description thereof will be omitted.

[Idling stop system]
The IDSS 20 of this example includes a determination unit 30, a hydraulic pressure control unit 40, and a stop control unit 50. The IDS-ECU 21 can be used for the determination unit 30, the hydraulic pressure control unit 40, and the stop control unit 50, as in the first embodiment.

(Judgment part)
When the IDS condition other than the brake fluid pressure condition of the drive wheel is satisfied when the vehicle 1 is stopped and the engine 80 is idling, the determination unit 30 determines that the braking force of the drive wheel is based on the brake fluid pressure of the drive wheel. It is determined whether the driving force is lower than the driving force. The IDS condition is as described above.

(Hydraulic pressure controller)
When the determination unit 30 determines that the braking force of the driving wheels is lower, the hydraulic control unit 40 sets the braking force of the driving wheels to zero, and the braking force of the driven wheels is only the braking force of the driven wheels. The brake fluid pressure of the driven wheel is increased so as to be equal to or higher than the threshold value at which the brake is stopped. When the braking force is zero, it means that the friction material of the brake main body 72 and the mating material (the disc rotor or the brake drum) are separated from each other. In order to reduce the braking force of the drive wheels to zero, it is possible to reduce the brake fluid pressure of the drive wheels to zero. The reduction of the brake fluid pressure of the drive wheels and the increase of the brake fluid pressure of the driven wheels can be performed by controlling the operation of the brake actuator 77 by the fluid pressure control unit 40.

(Stop control unit)
The stop control unit 50 stops idling of the engine 80. The idling is stopped by the stop control unit 50 when the braking force of the drive wheels becomes zero and the braking force of the driven wheels becomes equal to or more than a threshold value, or when the determination unit 30 determines that the braking force of the drive wheels is not less than the driving force of the drive wheels. It is performed when it is determined that the condition is satisfied.

(Control procedure)
A control procedure of the IDSS 20 of the vehicle 1 according to the second embodiment will be described with reference to the graph of FIG. 2 and the flowchart of FIG. The flowchart of FIG. 4 shows the control procedure of the IDSS 20 when the drive system is front-wheel drive. When the IDS condition other than the brake fluid pressure condition of the drive wheels is satisfied when the vehicle 1 is stopped and idling, the IDS control is started.

Based on the measurement result of the brake fluid pressure sensor 75, the determination unit 30 determines whether the braking force of the front wheel 61 based on the brake fluid pressure of the front wheel 61, which is the driving wheel, is lower than the driving force of the front wheel 61. That is, it is determined whether the braking force of the front wheels 61 is less than a threshold value x1 at which the vehicle 1 can be stopped only by the braking force of the front wheels 61 (step S21).

When the condition of step S21 is satisfied, the braking force of the rear wheel 62 based on the brake fluid pressure of the rear wheel 62 falls below the threshold value y1. In this case, the hydraulic pressure control unit 40 operates the brake actuator 77 to reduce the brake hydraulic pressure of the brake main body 71 of the front wheel 61 so that the braking force of the front wheel 61 becomes zero (step S22). Further, the hydraulic pressure control unit 40 operates the brake actuator 77 to increase the brake hydraulic pressure of the brake main body 72 of the rear wheel 62 so that the braking force of the rear wheel 62 becomes equal to or more than the threshold value x1 (step S23). Step S22 and step S23 may be performed simultaneously or sequentially. When performing in order, for example, step S23 and step S22 may be performed in order. If step S23 and step S22 are performed in this order, the vehicle 1 is reliably maintained in the stopped state without moving forward due to the creep phenomenon.

Then, the stop control unit 50 performs IDS (step S24). Then, this control ends.

When the condition of step S21 is not satisfied, that is, when the braking force of the front wheels 61 satisfies the threshold value x1 or more (the driving force of the front wheels 61 or more), the control ends through step S24.

The control procedure of the IDSS 20 in the rear wheel drive may be the same as the control procedure of the IDSS 20 in the front wheel drive. In that case, the front wheel 61 in the control procedure of the IDSS 20 in the front wheel drive may be replaced with the rear wheel 62, the threshold value x1 may be replaced with the threshold value y1, and the brake body 71 may be replaced with the brake body 72. In the case of rear wheel drive, it is preferable to go through the control procedure of the IDSS 20 according to Appendix 1 described later. The control procedure of the IDSS 20 in 4WD may be the same as the control procedure of the IDSS 20 in front wheel drive. In the case of 4WD, the control procedure can be simplified and the load on the IDS-ECU 21 can be reduced as compared with Appendix 1 described later.

[Action effect]
The vehicle 1 according to the second embodiment can suppress the generation of the abnormal noise of the brake body that occurs when the engine 80 stops idling, as in the first embodiment. Before the idling of the engine 80 is stopped, the braking force of the front wheel 61, which is the driving wheel, can be made zero by the hydraulic pressure control unit 40, so that the friction material of the brake body 71 of the front wheel 61 and the mating material can be separated from each other. .. Therefore, when idling is stopped, the friction material of the brake body 71 of the front wheel 61 does not make sliding contact with the mating material. Then, before the idling of the engine 80 is stopped, the braking force of the rear wheels 62 is increased to a threshold value y1 or more by the hydraulic pressure control unit 40, so that the braking force of the driving wheels is set to zero and the idling of the vehicle 1 is stopped. The suspension can be maintained.

The present invention is not limited to these examples, but is defined by the claims, and is intended to include meanings equivalent to the claims and all modifications within the scope.

<Note>
The following supplementary notes will be further disclosed in relation to the embodiments of the present invention described above.

[Appendix 1]
A vehicle having rear wheels to which a driving force of an engine acts when the vehicle is stopped,
When the idling stop conditions other than the brake fluid pressure conditions for the front wheels and the rear wheels are satisfied when the vehicle is stopped and the engine is idling,
A first determination unit that determines whether or not the braking force of the rear wheels is lower than the driving force of the rear wheels based on the brake fluid pressure of the rear wheels,
A second determination unit that determines whether or not the braking force of the front wheels is below a threshold value that allows the vehicle to be stopped only by the braking force of the front wheels, based on the brake fluid pressure of the front wheels,
When it is determined by the first determination unit that the braking force of the rear wheels is lower, a first hydraulic pressure control unit that makes the braking force of the rear wheels zero,
When it is determined that the braking force of the front wheels is lower by the second determination unit, a second hydraulic pressure control unit that increases the brake fluid pressure of the front wheels so that the braking force of the front wheels is equal to or more than the threshold value,
A vehicle comprising: a stop control unit that stops idling of the engine when the braking force of the rear wheels becomes zero and the braking force of the front wheels becomes equal to or more than the threshold value.

In the vehicle of Appendix 1, the braking force of the rear wheels, which are the driving wheels, can be made zero by the first hydraulic pressure control unit before the idling of the engine is stopped, so that the friction material of the brake body of the rear wheels and the mating material are mutually Can be separated. Therefore, when idling is stopped, the friction material of the brake body of the rear wheel does not come into sliding contact with the mating material. Then, before the idling of the engine is stopped, the braking force of the front wheels is increased by the second hydraulic pressure control unit to a threshold value at which the vehicle is stopped only by the braking force of the front wheels. Therefore, even if idling is stopped by setting the braking force of the driving wheels to zero, the vehicle can be kept stopped.

<<Reference Example 1>>
〔vehicle〕
A vehicle 1 according to Reference Example 1 will be described with reference to FIGS. 2, 5, and 6. The vehicle 1 according to the reference example 1 has the rear wheels 62 on which the driving force of the engine 80 acts when the vehicle 1 is stopped. The drive type of the vehicle 1 of this example may be rear wheel drive or 4WD. One of the features of the vehicle 1 according to Reference Example 1 is that when the vehicle 1 is stopped and the engine 80 is idling, when the IDS conditions other than the brake fluid pressure conditions of the front wheels 61 and the rear wheels 62 are satisfied, the control of the rear wheels 62 is performed. If the power is less than the driving force of the rear wheel 62, the braking force of the rear wheel 62 is set to zero, and after increasing the braking force of the front wheel 61 to a specific threshold value or more, the IDSS 20 that stops idling of the engine 80 is set. There is a point to prepare. Since the outline of the vehicle 1 of this example is the same as that of the first embodiment, the description thereof will be omitted.

[Idling stop system]
The IDSS 20 of this example includes a first determination unit 31, a second determination unit 32, a first hydraulic pressure control unit 41, a second hydraulic pressure control unit 42, and a stop control unit 50. As with the first embodiment, the IDS-ECU 21 can be used for the first determination unit 31, the second determination unit 32, the first hydraulic pressure control unit 41, the second hydraulic pressure control unit 42, and the stop control unit 50.

(First determination unit)
When the vehicle 1 is stopped and the engine 80 is idling, when the IDS conditions other than the brake fluid pressure conditions of the front wheels 61 and the rear wheels 62 are satisfied, the first determination unit 31 determines the rear wheel pressure based on the brake fluid pressure of the rear wheels 62. It is determined whether the braking force of 62 is less than the driving force of the rear wheel 62. The IDS condition is as described above.

(Second determination unit)
When the IDS condition other than the brake fluid pressure conditions of the front wheels 61 and the rear wheels 62 is satisfied when the vehicle 1 is stopped and the engine 80 is idling, the second determination unit 32 determines the front wheel 61 based on the brake fluid pressure of the front wheels 61. It is determined whether the braking force is below a threshold value at which the vehicle 1 can be stopped only by the braking force of the front wheels 61.

(First hydraulic pressure controller)
When the first determination unit 31 determines that the braking force of the rear wheels 62 is less than the driving force of the rear wheels 62, the first hydraulic pressure control unit 41 sets the braking force of the rear wheels 62 to zero. To reduce the braking force of the rear wheels 62 to zero, it is possible to reduce the brake fluid pressure of the rear wheels 62 to zero by controlling the operation of the brake actuator 77 by the first hydraulic pressure control unit 41.

(Second hydraulic pressure controller)
When the second determination unit 32 determines that the braking force of the front wheels 61 is below the threshold value, the second hydraulic pressure control unit 42 sets the brake fluid pressure of the front wheels 61 so that the braking force of the front wheels 61 exceeds the threshold value. Boost. The brake fluid pressure of the front wheels 61 can be increased by controlling the operation of the brake actuator 77 by the second fluid pressure control unit 42.

(Stop control unit)
The stop control unit 50 stops the idling of the engine 80 when the braking force of the rear wheels 62 becomes zero and the braking force of the front wheels 61 exceeds the threshold value. In addition, the stop control unit 50 stops the idling of the engine 80 when the first determination unit 31 determines that the braking force of the rear wheels 62 satisfies the driving force of the rear wheels 62 or more.

(Control procedure)
A control procedure of the IDSS 20 of the vehicle 1 according to the reference example 1 will be described based on the graph of FIG. 2 and the flowchart of FIG. The flowchart of FIG. 6 shows a control procedure of the IDSS 20 in rear wheel drive. When the IDS conditions other than the brake fluid pressure conditions for the driving wheels are satisfied when the vehicle 1 is stopped and idling, the IDS control is started.

Based on the measurement result of the brake fluid pressure sensor 75, the first determination unit 31 determines whether the braking force of the rear wheel 62 based on the brake fluid pressure of the rear wheel 62, which is the driving wheel, is lower than the driving force of the rear wheel 62. .. That is, it is determined whether the braking force of the rear wheel 62 is less than the threshold value y1 (step S31).

When the condition of step S31 is satisfied, the braking force of the front wheel 61 based on the brake fluid pressure of the front wheel 61, which is the driven wheel, is determined by the second determination unit 32 based on the measurement result of the brake fluid pressure sensor 75. It is determined whether or not the value is below a threshold value x1 at which 1 can be stopped (step S32).

When the condition of step S32 is satisfied, the second hydraulic pressure control unit 42 operates the brake actuator 77 to increase the brake hydraulic pressure of the brake main body 71 of the front wheel 61 so that the braking force of the front wheel 61 becomes equal to or more than the threshold value x1. (Step S33). Further, the first hydraulic pressure control unit 41 operates the brake actuator 77 to reduce the brake hydraulic pressure of the brake main body 72 of the rear wheel 62 so that the braking force of the rear wheel 62 becomes zero (step S34). By performing step S33 and step S34 in this order, the vehicle 1 is reliably maintained in the stopped state without moving forward due to the creep phenomenon. Step S33 and step S34 may be performed simultaneously or sequentially.

Subsequently, the stop control unit 50 performs IDS (step S35). Then, this control ends.

When the condition of step S31 is not satisfied, that is, when the braking force of the rear wheel 62 satisfies the threshold value y1 or more, this control is ended via step S35.

When the condition of step S32 is not satisfied, that is, when the braking force of the front wheel 61 satisfies the threshold value x1 or more, this control is ended through step S34 and step S35 in order.

The control procedure of the IDSS 20 in 4WD may be the same as the control procedure of the IDSS 20 in rear wheel drive. In the case of 4WD, the load on the brake actuator 77 can be reduced as compared with the second embodiment. This is because the brake fluid pressure of the front wheel 61 with respect to the brake main body 71 is larger than that of the rear wheel 62, so that the rate of increasing the brake fluid pressure can be reduced as compared with the case of increasing the brake fluid pressure of the rear wheel 62.

[Action effect]
The vehicle 1 according to the reference example 1 can suppress the generation of the abnormal noise of the brake main body that occurs when the idling of the engine 80 is stopped, as in the first and second embodiments. Before the idling of the engine 80 is stopped, the braking force of the rear wheel 62, which is a driving wheel, can be made zero by the first hydraulic pressure control unit 41, so that the friction material of the brake body 72 of the rear wheel 62 and the mating material are separated from each other. It can be in a closed state. Therefore, when idling is stopped, the friction material of the brake body 72 of the rear wheel 62 does not come into sliding contact with the mating material. Then, before the idling of the engine 80 is stopped, the braking force of the front wheels 61 is increased to a threshold value x1 or more by the second hydraulic pressure control unit 42, so that the braking force of the driving wheels is set to zero and the idling is stopped. Can continue to be maintained.

1 vehicle 20 IDSS
21 IDS-ECU
30 determination unit 31 first determination unit 32 second determination unit 40 hydraulic pressure control unit 41 first hydraulic pressure control unit 42 second hydraulic pressure control unit 50 stop control unit 61 front wheel 62 rear wheel 71 brake body 72 brake body 73 brake pedal 74 master cylinder 75 brake fluid pressure sensor 76 booster 77 brake actuator 80 engine

Claims (2)

A vehicle having driving wheels to which a driving force of an engine acts when the vehicle is stopped,
When an idling stop condition other than the brake fluid pressure condition of the drive wheel is satisfied when the vehicle is stopped and the engine is idling, the braking force of the drive wheel is determined based on the brake fluid pressure of the drive wheel. And a determination unit that determines whether or not
When the determination unit determines that the braking force of the drive wheel is lower, a hydraulic pressure control unit that increases the brake hydraulic pressure of the drive wheel so that the braking force of the drive wheel becomes equal to or greater than the drive force of the drive wheel. When,
A vehicle comprising: a stop control unit that stops idling of the engine when the braking force of the drive wheels becomes equal to or greater than the drive force of the drive wheels. A vehicle having driving wheels to which a driving force of an engine acts when the vehicle is stopped,
When an idling stop condition other than the brake fluid pressure condition of the drive wheel is satisfied when the vehicle is stopped and the engine is idling, the braking force of the drive wheel is determined based on the brake fluid pressure of the drive wheel. And a determination unit that determines whether or not
When the determination unit determines that the braking force of the driving wheel is lower, the brake fluid pressure of the driving wheel is reduced so that the braking force of the driving wheel becomes zero, and the braking force of the driven wheel is reduced. A hydraulic pressure control unit for increasing the brake hydraulic pressure of the driven wheels so as to be equal to or more than a threshold value at which the vehicle can be stopped only by the braking force of the driving wheels,
A vehicle comprising: a stop control unit that stops idling of the engine when the braking force of the driving wheels becomes zero and the braking force of the driven wheels becomes equal to or more than the threshold value.

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