JP5682758B2 - Idle stop vehicle - Google Patents

Description

  The present invention relates to a control technology for a vehicle including an idle stop device.

2. Description of the Related Art Conventionally, an idle stop device that automatically stops operation of an internal combustion engine when stopping traveling at an intersection or the like is known as means for improving the fuel efficiency of an automobile.
The idle stop device automatically stops the idle operation of the internal combustion engine when a predetermined stop condition is satisfied, such as by stopping at an intersection when the vehicle travels, and then stops the internal combustion engine when the predetermined restart condition is satisfied. The vehicle is restarted and started.

  Furthermore, in vehicles equipped with an idle stop device, an auxiliary power supply device (voltage compensation circuit) such as a DC-DC converter, for example, is installed to maintain brakes and transmission hydraulic pressure when the battery voltage drops during restart. A technique for avoiding the influence of the above has been proposed. In a vehicle equipped with such an auxiliary power supply device, when the internal combustion engine is stopped by an idle stop device on a ramp, even if the battery voltage is lowered, the operation of the brake device or the like is ensured, and the vehicle is unexpected. The movement can be prevented (Patent Document 1).

JP 2002-38984 A

  However, in the vehicle of Patent Document 1, even when the auxiliary power supply device or the brake device is out of order, automatic stop by the idle stop device may be permitted on the ramp. Therefore, after determining whether or not the idle stop device actually operates normally, a method of allowing subsequent automatic stop is conceivable. In such a case, the internal combustion engine may be stopped in a state where the auxiliary power supply device or the brake device cannot be sufficiently operated, leading to an unexpected movement of the vehicle.

  The present invention has been made to solve such a problem, and the object of the present invention is to provide a highly reliable idle that can suppress the unexpected movement of the vehicle even if a failure is judged on the ramp. It is to provide a stop vehicle.

To achieve the above object, an idle stop vehicle according to claim 1, an internal combustion engine mounted on the vehicle when the road gradient detecting means for detecting a road gradient on which the vehicle is stopped, the Tokoro constant stop condition is satisfied Is stopped automatically , and then the internal combustion engine is restarted when a predetermined restart condition is satisfied, stop holding means for restricting movement of the vehicle, and hydraulic oil is supplied to the stop holding means and an electrical load to an auxiliary power source means for supplying power to the electric load, and a failure determining means for performing at least one of the failure judgment of said auxiliary power unit or the electrical load, the idle stop system, the from the vehicle key switch is turned ON until experiencing the failure determination by the failure determination means, as the stop condition, is detected by the road surface gradient detecting means The road surface gradient is less than or equal to a second predetermined value, and when one or both of the auxiliary power source means or the electric load determined by the failure determination means are determined to be normal, As the stop condition, it is set that the road surface gradient detected by the road surface gradient detecting means is not more than a first predetermined value larger than the second predetermined value .
According to this aspect, even if there is a failure, the vehicle is prohibited from being automatically stopped at a gradient larger than the second predetermined value until the failure determination of the auxiliary power source or the electric load that operates at the restart is completed. Runaway and the like are suppressed, and the reliability of the vehicle at the time of failure determination can be ensured. In addition, after it is confirmed that the failure is normal by the failure determination, the automatic stop at a slope not greater than the first predetermined value that is greater than the second predetermined value is permitted, thereby increasing the opportunity for executing the automatic stop and improving the fuel efficiency. Can be improved.

Further, in the idle stop vehicle according to claim 2, in the claim 1, when the idle stop device determines that the auxiliary power supply means or the electric load has failed by the failure determination means, The road gradient detected by the road gradient detector is set to be equal to or less than the second predetermined value .
According to this aspect, even when it is determined that there is a failure, the automatic stop is executed on the low slope road whose road surface gradient is equal to or less than the second predetermined value. Therefore, the opportunity for executing the automatic stop can be increased, and the fuel consumption can be improved. .
According to a third aspect of the present invention, there is provided the idle stop vehicle according to the first or second aspect, wherein the failure determination unit is configured such that the internal combustion engine is on an inclined road having a road surface gradient detected by the road surface gradient detection unit equal to or less than the second predetermined value. It is characterized in that failure determination is performed when the automatic stop is performed.
According to this aspect, it is possible to determine a failure based on the movement of the vehicle, and it is not necessary to provide a new sensor for detecting the failure.

The idle stop vehicle according to claim 4 is the idle stop vehicle according to any one of claims 1 to 3, wherein the failure determination means performs failure determination of the electric load during the automatic stop of the internal combustion engine. A failure determination of the auxiliary power supply means is performed at the time of restart .
According to this aspect, it is possible to easily identify the failure site.
Further, the idle stop vehicle according to claim 5, in any one of claims 1 to 4, wherein the idle stop system, as the stop condition, further the working oil pressure of the stop holding means is equal to or greater than a predetermined value The failure determination means is configured to determine a failure based on an operating state of the stop holding means when the internal combustion engine is restarted.
According to this aspect, the failure determination can be easily performed.

According to the present invention, it is possible to provide a highly reliable idle stop vehicle that can suppress unexpected movement of a vehicle even if a failure is determined on an inclined road.

1 is a schematic configuration diagram of an idle stop device for a vehicle according to an embodiment of the present invention. It is a flowchart which shows the execution determination point of idle stop control in ECU which concerns on the 1st Embodiment of this invention. It is a flowchart which shows the execution determination point of idle stop control in ECU which concerns on the 1st Embodiment of this invention. It is a flowchart which shows the subroutine of an engine automatic stop availability determination process. It is a flowchart which shows the subroutine of an engine restart necessity determination process. It is a flowchart which shows the execution determination point of idle stop control in ECU which concerns on the 2nd Embodiment of this invention. It is a flowchart which shows the execution determination point of idle stop control in ECU which concerns on the 2nd Embodiment of this invention. It is a flowchart which shows the execution determination point of idle stop control in ECU which concerns on the 3rd Embodiment of this invention. It is a flowchart which shows the execution determination point of idle stop control in ECU which concerns on the 3rd Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram of an idle stop device 1 according to an embodiment of the present invention.
The idle stop vehicle (hereinafter referred to as a vehicle) of this embodiment includes an idle stop device 1.
The idle stop device 1 automatically operates the engine 11 (internal combustion engine) when a predetermined idle stop condition (stop condition) is satisfied, for example, by stopping at an intersection when the vehicle travels, as in a known idle stop device. After that, the engine 11 is restarted and the vehicle is started when a predetermined restart condition is satisfied.

As idle stop conditions, in addition to basic start conditions such as vehicle speed 0 and brake (vehicle service brake) ON, brake hydraulic pressure state, engine 11 temperature state, battery state, air conditioner operation request, accelerator opening Etc. are set.
As shown in FIG. 1, the vehicle is provided with a braking device 12 (stop holding means) for braking the vehicle. The braking device 12 is a vehicle braking device, for example, and has a function of braking so as to prevent the vehicle from moving when the engine 11 is automatically stopped and restarted by the idle stop device 1.

  Further, the vehicle is provided with an auxiliary power source 13 (auxiliary power source means) and an electric pump 14 (electric load) in order to prevent malfunction of the braking device 12 due to a battery voltage drop. The auxiliary power supply 13 is a power supply device different from the vehicle battery that supplies electric power to the engine starting motor, and is configured, for example, by adding a battery, a capacitor, or a DC-DC converter to these. The electric pump 14 is driven by the auxiliary power source 13 and has a function of supplying hydraulic oil to the brake device 12 so that the brake device 12 can be operated.

  Further, the vehicle according to the present embodiment includes a vehicle speed sensor 2 for detecting the vehicle speed, an inclination angle sensor 3 (road surface gradient detecting means) for detecting the vehicle inclination angle as a road surface gradient θ, and a brake master cylinder hydraulic pressure P for a service brake of the vehicle. An electronic control unit (hereinafter, referred to as a control unit for the idle stop device), a brake pressure sensor 4 for detecting the engine pressure, a coolant temperature sensor 5 for detecting the coolant temperature of the engine 11, an accelerator position sensor 6 for detecting the accelerator position. ECU10).

The ECU 10 includes an input / output device, a storage device (ROM, RAM, nonvolatile RAM, etc.), a central processing unit (CPU), and the like.
The vehicle speed sensor 2, the inclination angle sensor 3, the brake pressure sensor 4, and the cooling water temperature sensor 5 are electrically connected to the input side of the ECU 10, and detection information from these various sensors is input. Various vehicle information relating to the idle stop condition such as a vehicle battery deterioration state, a battery charge state, and an air conditioner operation switch operation information is input.

An engine 11, a braking device 12, and an electric pump 14 are connected to the output side of the ECU 10 so that the operation thereof can be controlled.
The ECU 10 includes an idle stop control unit 20 (automatic stop control unit) as a control unit of the idle stop device 1 and a failure determination unit 21 (failure determination unit) that performs a failure determination on a device related to the idle stop device 1. Yes.

From the various information input to the ECU 10, the idle stop control unit 20 automatically stops the engine 11 when the idle stop condition is satisfied as described above, and restarts the engine 11 when the restart condition is satisfied thereafter. Let
Hereinafter, the first embodiment of the present invention will be described with reference to FIGS.
FIGS. 2 and 3 are flowcharts showing execution determination points for idle stop control in the ECU 10 according to the first embodiment of the present invention.

This routine is repeated when the vehicle power is turned on.
First, the vehicle speed V is input from the vehicle speed sensor 2 in step S10 shown in FIG. Then, the process proceeds to step S20.
In step S20, it is determined whether or not the vehicle is stopped from the vehicle speed V input in step S10. Specifically, it is determined whether or not the vehicle is stopped depending on whether or not the vehicle speed V is 0 or less than or equal to a set value set near 0. If the vehicle is stopped, the process proceeds to step S30. If the vehicle is not stopped, this routine is terminated.

In step S30, the road surface gradient θ is input from the inclination angle sensor 3. Then, the process proceeds to step S40.
In step S40, it is determined whether or not the vehicle key switch is ON. If it is ON, the process proceeds to step S50. If it is OFF, the process proceeds to step S80.
In step S50, it is determined whether or not the auxiliary power supply failure determination experience flag Fa is set. If the auxiliary power failure determination experience flag Fa is set, specifically, if the auxiliary power failure determination experience flag Fa is 1, the process proceeds to step S60. If the auxiliary power failure determination experience flag Fa is not set, specifically, if the auxiliary power failure determination experience flag Fa is 0, the process proceeds to step S90.

  In step S60, it is determined whether or not the auxiliary power failure detection flag Fb is not set. If the auxiliary power failure detection flag Fb is not set, specifically, if the auxiliary power failure detection flag Fb is 0, the process proceeds to step S70. When the auxiliary power failure detection flag Fb is set, specifically, when the auxiliary power failure detection flag Fb is 1, the present routine is terminated.

  In step S70, it is determined whether or not the road surface gradient θ input in step S30 is equal to or less than a first predetermined value θ1. The first predetermined value θ1 may be set within the range of the gradient that allows the engine 11 to be automatically stopped and in the vicinity of the upper limit value thereof. When the road surface gradient θ is equal to or less than the first predetermined value θ1, the process proceeds to step S100 in FIG. When the road surface gradient θ is larger than the first predetermined value θ1, this routine is ended.

In step S80, the auxiliary power failure detection flag Fb is cleared to zero. Then, this routine ends.
In step S90, it is determined whether or not the road surface gradient θ input in step S30 is equal to or smaller than a second predetermined value θ2. The second predetermined value θ2 is a value smaller than the first predetermined value θ1, and the range in which the movement of the vehicle does not cause a problem when the engine 11 is restarted even if the operation of the braking device 12 is insufficient. Can be set within. When the road surface gradient θ is equal to or smaller than the second predetermined value θ2, the process proceeds to step S100 in FIG. When the road surface gradient θ is larger than the second predetermined value θ2, this routine ends.

In step S100 shown in FIG. 3, a subroutine for determining whether or not to automatically stop the engine shown in FIG. 5 is executed, and it is determined whether or not the engine 11 can be automatically stopped by the idle stop control unit 20. Then, the process proceeds to step S110.
If it is determined in step S110 that the engine 11 can be automatically stopped in step S100, the process proceeds to step S120. If it is determined that the automatic stop of the engine 11 is not possible, this routine is terminated.

In step S120, the engine 11 is automatically stopped by the idle stop control unit 20. Then, the process proceeds to step S130.
In step S130, an engine restart necessity determination subroutine shown in FIG. 5 is executed to determine whether the engine 11 needs to be restarted after automatic stop. Then, the process proceeds to step S140.

If it is determined in step S140 that the engine 11 needs to be restarted in step S130, the process proceeds to step S150. If it is determined that restart of the engine 11 is not necessary, the process returns to step S130.
In step S150, the engine 11 is restarted by the idle stop control unit 20. Then, the process proceeds to step S 160.

  In step S160, the failure determination unit 21 performs failure determination of the auxiliary power supply 13. The failure determination of the auxiliary power supply 13 is determined based on the operating state of the braking device 12. Specifically, when power can be supplied from the auxiliary power source 13 to the electric pump 14 and the braking device 12 is operating normally at the time of restart, the auxiliary power source 13 is normal and the braking device 12 is operating normally. If not, it is determined that the auxiliary power supply 13 has failed. Then, the process proceeds to step S170.

In step S170, it is determined whether or not the auxiliary power supply failure determination experience flag Fa is set. When the auxiliary power failure determination experience flag Fa is set (Fa = 1), the process proceeds to step S180. If the auxiliary power failure determination experience flag Fa is not set (Fa = 0), the process proceeds to step S200.
In step S180, when it is determined in the auxiliary power supply failure determination performed in step S160 that the auxiliary power supply is defective, the process proceeds to step S190. If it is determined that there is no failure, the process proceeds to step S210.

In step S190, the auxiliary power failure detection flag Fb is set to 1. Then, this routine ends.
In step S200, the auxiliary power failure determination experience flag Fa is set to 1. Then, the process proceeds to step S180.
In step S210, the auxiliary power failure detection flag Fb is not set, that is, cleared to 0. Then, this routine ends.

FIG. 4 is a flowchart of a subroutine for engine automatic stop propriety determination processing.
As shown in FIG. 4, in the engine automatic stop propriety determination process, first, in step S400, it is determined whether or not the battery is in a deteriorated state. Specifically, it is determined whether or not the internal resistance of the battery of the vehicle is less than 10 mΩ, and if it is less than 10 mΩ, it is determined that the battery is not deteriorated, and the process proceeds to step S410.

In step S410, it is determined whether or not the battery charge state is sufficient. Specifically, it is determined whether or not the amount of charge of the vehicle battery is 80% or more. If it is 80% or more, it is determined that the battery charge state is sufficient, and the process proceeds to step S420.
In step S420, it is determined whether or not an air conditioner operation request has been made. Specifically, it is determined whether or not an air conditioner operation switch is turned off. If it is turned off, it is determined that an air conditioner operation request has not been made, and the process proceeds to step S430.

In step S430, it is determined whether or not the engine 11 is in a warm-up state. Specifically, it is determined whether or not the coolant temperature input from the coolant temperature sensor 5 is 60 degrees or more, and if it is 60 degrees or more, it is determined that the engine 11 is in a warm-up state, Proceed to step S440.
In step S440, it is determined whether or not the hydraulic pressure of the brake master cylinder of the vehicle service brake is sufficient. Specifically, it is determined whether or not the hydraulic pressure P of the brake master cylinder input from the brake pressure sensor 4 is equal to or higher than a reference brake pressure Ps (for example, 0.5 MPa). And the process proceeds to step S450.

In step S450, it is determined whether or not the accelerator opening input from the accelerator opening sensor 6 is zero. If the accelerator opening is 0, the process proceeds to step S460.
In step S460, it is determined that the engine can be automatically stopped. Then, this subroutine is returned.
If it is determined in step S400 that the internal resistance of the battery is 10 mΩ or more, if it is determined in step S410 that the charge amount of the battery is less than 80%, it is determined in step S420 that the operation switch of the air conditioner is ON. If it is determined in step S430 that the engine coolant temperature is less than 60 degrees, if it is determined in step S440 that the hydraulic pressure of the brake master cylinder is less than 0.5 MPa, or if the accelerator opening is 0 in step S450. If it is determined that the value is larger, the process proceeds to step S470.

In step S470, it is determined that the engine cannot be automatically stopped. Then, this subroutine is returned.
FIG. 5 is a flowchart of a subroutine of engine restart necessity determination processing.
As shown in FIG. 5, in the engine restart necessity determination process, first, in step S500, it is determined whether or not the battery charge state is sufficient. Specifically, it is determined whether or not the amount of charge of the vehicle battery is 80% or more. If it is 80% or more, it is determined that the battery charge state is sufficient, and the process proceeds to step S510.

In step S510, it is determined whether an air conditioner operation request has been made. Specifically, it is determined whether or not the operation switch of the air conditioner is turned off. If it is turned off, it is determined that the operation request of the air conditioner is not requested, and the process proceeds to step S520.
In step S520, it is determined whether or not the engine 11 is in a warm-up state. Specifically, when the coolant temperature input from the coolant temperature sensor 5 is 60 degrees or more, it is determined that the engine 11 is in a warm-up state, and the process proceeds to step S530.

In step S530, it is determined whether or not the hydraulic pressure of the brake master cylinder of the service brake is sufficient. Specifically, it is determined whether or not the hydraulic pressure P of the brake master cylinder input from the brake pressure sensor 4 is equal to or higher than a reference brake pressure Ps (for example, 0.5 MPa). And the process proceeds to step S540.
In step S540, it is determined whether or not the accelerator opening is zero. If the accelerator opening is 0, the process proceeds to step S550.

In step S550, it is determined that engine restart is unnecessary. Then, this subroutine is returned.
If it is determined in step S500 that the charge amount of the battery is less than 80%, if it is determined in step S510 that the air conditioner operation switch is ON, then in step S520, the engine coolant temperature is less than 60 degrees. If it is determined, if it is determined in step S530 that the hydraulic pressure P of the brake master cylinder is less than the reference brake pressure Ps, or if it is determined that the accelerator opening is greater than 0 in S540, the process proceeds to step S560.

In step S560, it is determined that engine restart is necessary. Then, this subroutine is returned.
With the configuration as described above, the vehicle according to the present embodiment includes the auxiliary power supply 13, so that power is supplied from the auxiliary power supply 13 even when the battery voltage decreases during restart after the engine 11 is automatically stopped. Then, the electric pump 14 is operated, and hydraulic oil is supplied from the electric pump 14 to ensure the operation of the braking device 12. Therefore, when the vehicle stops on the ramp and the engine 11 automatically stops, braking is sufficiently performed even if the battery is not sufficiently charged, and movement of the vehicle at the time of automatic stop and restart is prevented. be able to.

Since the engine 11 is controlled not to be automatically stopped when the road surface gradient θ exceeds at least the first predetermined value θ1, the vehicle is prevented from moving due to the automatic stop of the engine 11 on a high slope road. Can do.
In the present embodiment, especially when the failure determination of the auxiliary power supply 13 is not performed after the key switch is turned on, the automatic stop of the engine 11 is regulated using the second predetermined value θ2 as a threshold value, and the failure of the auxiliary power supply 13 is detected. When the determination is performed at least once, the automatic stop is regulated using the first predetermined value θ1 larger than the second predetermined value θ2 as a threshold value. That is, until the idle stop device 1 is normally executed, it is prohibited to automatically stop at a gradient greater than the second predetermined value θ2 until it is determined with a low gradient. Even if the device is out of order, vehicle runaway or the like is suppressed, and the reliability of the vehicle at the time of the failure determination can be ensured. Further, when the auxiliary power supply failure is detected, the automatic stop is regulated thereafter, so that the reliability after the failure determination can be maintained even if the auxiliary power supply 13 is broken.

Further, in this embodiment, the auxiliary power supply 13 performs failure determination based on the operating state of the braking device 12 to restart when operating, a failure determination of the auxiliary power supply 1 3 can be easily performed.
Next, a second embodiment of the present invention will be described with reference to FIGS. 6 and 7 and FIGS.

FIGS. 6 and 7 are flowcharts showing execution determination points for idle stop control in the ECU 10 according to the second embodiment of the present invention.
This routine is repeated when the vehicle power is turned on.
First, in step S600 shown in FIG. 6, the vehicle speed V is input from the vehicle speed sensor 2. Then, the process proceeds to step S610.

In step S610, it is determined whether or not the vehicle is stopped from the vehicle speed V input in step S600. If the vehicle is stopped, the process proceeds to step S620. If the vehicle is not stopped, this routine is terminated.
In step S620, the road surface gradient θ is input from the inclination angle sensor 3. Then, the process proceeds to step S630.

In step S630, it is determined whether or not the vehicle key switch is ON. If it is ON, the process proceeds to step S640. If it is OFF, the process proceeds to step S680.
In step S640, it is determined whether or not the auxiliary power failure determination experience flag Fa is set. If the auxiliary power failure determination experience flag Fa is set (Fa = 1), the process proceeds to step S650. If the auxiliary power failure determination experience flag Fa is not set (Fa = 0), the process proceeds to step S690.

In step S650, it is determined whether or not the auxiliary power failure detection flag Fb is not set. If the auxiliary power failure detection flag Fb is not set (Fb = 0), the process proceeds to step S660. If the auxiliary power failure detection flag Fb is set (Fb = 1), the process proceeds to step S690.
In step S660, it is determined whether or not the road surface gradient θ input in step S620 is equal to or less than a first predetermined value θ1. When the road surface gradient θ is equal to or less than the first predetermined value θ1, the process proceeds to step S670. When the road surface gradient θ exceeds the first predetermined value θ1, this routine is terminated.

In step S670, it is determined whether or not the road surface gradient θ input in step S620 is greater than 0 and equal to or less than a second predetermined value θ2. When the road surface gradient θ is larger than 0 and equal to or smaller than the second predetermined value θ2, the process proceeds to step S100 in FIG. If the road surface gradient θ is 0 or less or greater than the second predetermined value θ2, the process proceeds to step S710 in FIG.
In step S680, the auxiliary power failure detection flag Fb is cleared to zero. Then, this routine ends.

In step S690, it is determined whether or not the road surface gradient θ input in step S620 is equal to or smaller than a second predetermined value θ2. When the road surface gradient θ is equal to or smaller than the second predetermined value θ2, the process proceeds to step S700. When the road surface gradient θ exceeds the second predetermined value θ2, this routine ends.
In step S700, it is determined whether or not the road surface gradient θ input in step S620 is not zero. If the road surface gradient θ is not 0, the process proceeds to step S100 in FIG. When the road surface gradient θ is 0, the process proceeds to step S710 in FIG.

In step S710 shown in FIG. 7, the engine automatic stop propriety determination subroutine shown in FIG. 4 is executed to determine whether or not the engine 11 can be automatically stopped by the idle stop control unit 20. Then, the process proceeds to step S720.
In step S720, if it is determined in step S710 that the engine 11 can be automatically stopped, the process proceeds to step S730. If it is determined that the automatic stop of the engine 11 is not possible, this routine is terminated.

In step S730, the engine 11 is automatically stopped by the idle stop control unit 20. Then, the process proceeds to step S740.
In step S740, the engine restart necessity determination subroutine shown in FIG. 5 is executed to determine whether or not the engine 11 needs to be restarted after automatic stop. Then, the process proceeds to step S750.

In step S750, if it is determined in step S740 that the engine 11 needs to be restarted, the process proceeds to step S760. If it is determined that restart of the engine 11 is unnecessary, the process returns to step S740.
In step S760, the engine 11 is restarted by the idle stop control unit 20. Then, this routine ends.

  By controlling as described above, in the second embodiment, as in the first embodiment, when the failure determination of the auxiliary power supply 13 is not performed after the key switch is turned on, the second predetermined value is set. When the stop of the engine 11 is regulated with θ2 as a threshold and the failure determination of the auxiliary power supply 13 is performed at least once, the engine 11 is automatically stopped with a first predetermined value θ1 larger than the second predetermined value θ2 as a threshold. Therefore, the reliability of the vehicle at the time of failure determination can be ensured.

  Further, in the second embodiment, the failure determination is performed when the road surface slope is automatically stopped on an inclined road having a second predetermined value θ2 or less, so that the electric motor 14 or the auxiliary device is moved by the vehicle moving during the automatic stop. It is possible to determine that the power supply 13 is in failure, and it is possible to determine failure in the electric motor 14 and the auxiliary power supply 13 without providing a new sensor for failure detection.

Even if there is a failure determination, automatic stop is executed on a low slope road whose road surface gradient is equal to or less than the second predetermined value θ2, so that the opportunity for execution of the automatic stop can be increased and fuel efficiency can be improved.
Next, a third embodiment of the present invention will be described with reference to FIGS.
FIGS. 8 and 9 are flowcharts showing execution determination points for idle stop control in the ECU 10 according to the third embodiment of the present invention.

This routine is repeated when the vehicle power is turned on.
First, in step S800 shown in FIG. 8, the vehicle speed V is input from the vehicle speed sensor 2. Then, the process proceeds to step S810.
In step S810, it is determined from the vehicle speed V input in step S800 whether or not the vehicle is stopped. If the vehicle is stopped, the process proceeds to step S820. If the vehicle is not stopped, this routine is terminated.

In step S820, the road surface gradient θ is input from the inclination angle sensor 3. Then, the process proceeds to step S830.
In step S830, it is determined whether or not the vehicle key switch is ON. If it is ON, the process proceeds to step S840. If it is OFF, the process proceeds to step S880.

  In step S840, it is determined whether or not the electric option failure detection flag Fc is not set. The electric option is an electric device that supplies hydraulic oil to a brake device or a transmission during automatic stop, and corresponds to the electric pump 14 in this embodiment. If the electric option failure detection flag Fc is not set, specifically, if the electric option failure detection flag Fc is 0, the process proceeds to step S850. When the electric option failure detection flag Fc is set, specifically, when the electric option failure detection flag Fc is 1, this routine is terminated.

In step S850, it is determined whether or not the auxiliary power supply failure determination experience flag Fa is set. If the auxiliary power failure determination experience flag Fa is set (Fa = 1), the process proceeds to step S860. If the auxiliary power failure determination experience flag Fa is not set (Fa = 0), the process proceeds to step S890.
In step S860, it is determined whether or not the auxiliary power failure detection flag Fb is not set. If the auxiliary power failure detection flag Fb is not set (Fb = 0), the process proceeds to step S870. If the auxiliary power failure detection flag Fb is set (Fb = 1), the process proceeds to step S890.

In step S870, it is determined whether or not the road surface gradient θ input in step S820 is equal to or less than a first predetermined value θ1. When the road surface gradient θ is equal to or less than the first predetermined value θ1, the process proceeds to step S900 in FIG. When the road surface gradient θ exceeds the first predetermined value θ1, this routine is terminated.
In step S880, the auxiliary power failure detection flag Fb is cleared to zero. Then, this routine ends.

In step S890, it is determined whether or not the road surface gradient θ input in step S820 is equal to or smaller than a second predetermined value θ2. When the road surface gradient θ is equal to or smaller than the second predetermined value θ2, the process proceeds to step S900 in FIG. When the road surface gradient θ exceeds the second predetermined value θ2, this routine ends.
In step S900 shown in FIG. 9, a subroutine for determining whether or not to automatically stop the engine shown in FIG. 5 is executed to determine whether or not the engine 11 can be automatically stopped by the idle stop control unit 20. Then, the process proceeds to step S910.

If it is determined in step S910 that the engine 11 can be automatically stopped in step S900, the process proceeds to step S920. When it is determined that the engine cannot be automatically stopped, this routine is terminated.
In step S920, the engine automatic stop by the idle stop control unit 20 is executed. Then, the process proceeds to step S930.

In step S930, the vehicle speed V is input from the vehicle speed sensor 2. Then, the process proceeds to step S940.
In step S940, it is determined from the vehicle speed V input in step S930 whether the vehicle is stopped. Specifically, it is determined whether or not the vehicle is stopped based on whether or not the vehicle speed V is 0 or less than a set value set close to 0. If the vehicle is stopped, the process proceeds to step S950. If the vehicle is not stopped, the process proceeds to step S1030.

In step S950, the electric option failure detection flag Fc is not set, that is, cleared to 0. Then, the process proceeds to step S960.
In step S960, the engine restart necessity determination subroutine shown in FIG. 5 is executed to determine whether or not the engine 11 needs to be restarted after automatic stop. Then, the process proceeds to step S970.

In step S970, if it is determined in step S960 that the engine 11 needs to be restarted, the process proceeds to step S980. If it is determined that restart of the engine 11 is not necessary, the process returns to step S960.
In step S980, the engine 11 is restarted by the idle stop control unit 20. Then, the process proceeds to step S990.

  In step S990, failure determination of the auxiliary power supply 13 is executed by the failure determination unit 21. The failure determination of the auxiliary power supply 13 is determined based on the operating state of the braking device 12. Specifically, it is possible to supply electric power from the auxiliary power supply 13 to the electric pump 14, and the failure determination of the auxiliary power supply 13 is performed depending on whether or not the braking device 12 is operating normally at the time of restart. Then, the process proceeds to step S1000.

In step S1000, it is determined whether or not the auxiliary power supply failure determination experience flag Fa is set. If the auxiliary power failure determination experience flag Fa is set, the process proceeds to step S1010. If the auxiliary power failure determination experience flag Fa is not set, the process proceeds to step S1050.
If it is determined in step S1010 that the auxiliary power supply 13 has failed in the auxiliary power supply failure determination performed in step S990, the process proceeds to step S1020. If it is determined that there is no failure, the process proceeds to step S1060.

In step S1020, the auxiliary power failure detection flag Fb is set to 1. Then, this routine ends.
In step S1030, the electric option failure detection flag Fc is set to 1. Then, the process proceeds to step S1040.
In step S1040, the engine 11 is restarted by the idle stop control unit 20. Then, this routine ends.

In step S1050, the auxiliary power failure determination experience flag Fa is set to 1. Then, the process proceeds to step S1010.
In step S1060, the auxiliary power failure detection flag Fb is not set, that is, cleared to 0. Then, this routine ends.
By controlling as described above, in the third embodiment, as in the first and second embodiments, when the failure determination of the auxiliary power supply 13 is not performed after the key switch is turned on, the second embodiment is performed. The automatic stop of the engine 11 is regulated with the predetermined value θ2 as a threshold value, and when the failure determination of the auxiliary power supply 13 is performed at least once, the first predetermined value θ1 larger than the second predetermined value θ2 is set as the threshold value. Therefore, the reliability of the vehicle at the time of failure determination can be ensured. Moreover, since the failure determination is performed based on the operating state of the braking device 12 at the time of restart, the failure determination of the auxiliary power supply 13 and the braking device 12 can be easily performed.

Furthermore, in the third embodiment, the failure determination of the electric pump 14 is also executed during the automatic stop. As a result, it is possible to more easily determine where the failure site is in the idle stop device 1.
In the above embodiment, the electric pump 14 is cited as the electric load that is operated by the auxiliary power source 13 when the engine is automatically stopped. However, other vehicle-mounted lights, air conditioners, and the like are also operated by the auxiliary power source 13 when the engine is automatically stopped. If it is an electric load that operates, the failure determination can be performed together with the auxiliary power supply 13 in the same manner as in the above embodiment.

1 Idle stop device 3 Tilt angle sensor 10 ECU
12 Braking Device 13 Auxiliary Power Supply 14 Electric Pump 20 Idle Stop Control Unit 21 Failure Determination Unit

Claims (5)

Road surface gradient detecting means for detecting the road surface gradient at which the vehicle stops;
The internal combustion engine mounted on the vehicle when Tokoro constant stop condition is satisfied is automatically stopped, then the idle stop system in which a predetermined restart condition is to restart the internal combustion engine when satisfied,
Stop holding means for restricting movement of the vehicle;
An electric load for supplying hydraulic oil to the stop holding means;
Auxiliary power means for supplying power to the electrical load;
A failure determination means for determining a failure of at least one of the auxiliary power supply means or the electrical load ;
The idle stop device has a second predetermined road surface gradient detected by the road surface gradient detecting unit as a stop condition from when the key switch of the vehicle is turned on until the failure determination unit experiences a failure determination. When it is determined that one or both of the auxiliary power supply means or the electric load determined by the failure determination means is normal among the auxiliary power supply means or the electric load, the road surface is used as the subsequent stop condition. An idle stop vehicle characterized in that the road surface gradient detected by the gradient detecting means is set to be equal to or less than a first predetermined value that is larger than the second predetermined value . In the idle stop device, when it is determined by the failure determination means that the auxiliary power supply means or the electric load has failed, as the subsequent stop condition, the road surface gradient detected by the road surface gradient detection means is the second 2. The idle stop vehicle according to claim 1, wherein the vehicle is set to be equal to or less than a predetermined value . Said failure determining means, according to claim 1, characterized in that the failure determination when the road surface gradient detected by the road gradient detecting means said internal combustion engine at a ramp below the second predetermined value is automatically stopped or The idle stop vehicle according to 2. The failure determination means makes a failure determination of the electric load during the automatic stop of the internal combustion engine, and makes a failure determination of the auxiliary power supply means when the internal combustion engine is restarted . The idle stop vehicle of any one of Claims . The idle stop device further sets, as the stop condition, that the operating hydraulic pressure of the stop holding means is a predetermined value or more,
The idle stop vehicle according to any one of claims 1 to 4 , wherein the failure determination means determines a failure based on an operating state of the stop holding means when the internal combustion engine is restarted.

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