JP3196076B2 - Motor vehicle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has an automatic transmission and reduces the driving force of creep when the engine is idling and the brake pedal is depressed at a predetermined low vehicle speed or lower, as compared to when the brake pedal is depressed and released. A prime mover including a driving force reducing device and / or a prime mover stopping device capable of automatically stopping the prime mover when the vehicle stops, and further including a brake fluid pressure holding device capable of continuously applying the brake fluid pressure of the wheel cylinder even when the brake pedal is released. It is related to a vehicle with an attachment.

[0002]

2. Description of the Related Art A motor vehicle equipped with a brake hydraulic pressure holding device (including a traction control system) has been known as a means for holding a brake hydraulic pressure of a wheel cylinder even when a brake pedal is released.

For example, Japanese Patent Laying-Open No. 9-202159 discloses a brake force control device for a vehicle having a starting clutch. This vehicle controls the engagement state of the starting clutch at extremely low vehicle speeds in the driving range, and reduces the driving force of creep in the idling state when the brake pedal is depressed as compared to when the brake pedal is fully released, thereby improving fuel efficiency. It prevents deterioration. Then, the braking force control device holds the braking force until it detects that the driving force of the creep has switched from a small state to a large state when the brake pedal is released, and until the driving force increases. The vehicle is prevented from retreating when starting on a slope due to a time lag. It should be noted that the creep is such that when the driving range such as the D range or the R range is selected by the shift lever of the vehicle having the automatic transmission, the vehicle crawls without depressing the accelerator pedal (the prime mover is idling). Is to move slowly.

[0004]

The problem to be solved by the present invention is disclosed in Japanese Patent Application Laid-Open No. 9-202.
If the brake force control device disclosed in Japanese Patent No. 159 fails, the brake force cannot be held until the driving force switches to a large state when the brake pedal is released. As a result, when the brake pedal is released when the vehicle starts on a slope, the vehicle moves backward.

In order to further prevent deterioration of fuel efficiency, in a vehicle in which the driving force is reduced when the brake pedal is depressed and the motor is automatically stopped when the vehicle stops, the motor is automatically started by releasing the brake pedal. And the driving force is increased. Further, in a vehicle that does not reduce the driving force but automatically stops the prime mover when the vehicle stops, the prime mover is automatically started by releasing the brake pedal. Also in the case where the motor vehicle having either one of the two configurations is provided with the brake fluid pressure holding device, the driving force switches to a large state when the brake pedal is released due to the failure of the brake fluid pressure holding device. Unable to hold the braking force until. As a result, when the brake pedal is released when the vehicle starts on a slope, the vehicle moves backward.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a motor with a motor capable of maintaining a large driving force or switching the driving force to a large state when a brake fluid pressure holding device breaks down, thereby preventing the vehicle from moving backward on a slope. It is to provide a vehicle.

[0007]

According to a first aspect of the present invention, there is provided a vehicle with a prime mover, wherein a drive range is selected from the prime mover when a travel range is selected in the transmission even when the accelerator pedal is released. A motor vehicle that transmits a driving force to the vehicle, and when the vehicle speed is equal to or less than a predetermined low vehicle speed, the magnitude of the driving force is switched according to the depression of a brake pedal,
A driving force reduction device that reduces the driving force when the brake pedal is depressed compared to when the brake pedal is released, and a brake fluid pressure that can continuously apply brake fluid pressure to the wheel cylinders even after the brake pedal is released A failure detection device that detects a failure of the brake fluid pressure holding device, and operates the driving force reduction device when the failure detection device detects a failure of the brake fluid pressure retention device. Is prohibited. According to this motorized vehicle,
Since the operation of the driving force reduction device is prohibited when the failure of the brake fluid pressure holding device is detected, the driving force is maintained at a large state even when the brake pedal is depressed and the vehicle speed becomes lower than a predetermined low vehicle speed. Further, even if a failure of the brake fluid pressure holding device is detected after the driving force has been reduced, the driving force can be immediately switched to the large state.

According to another aspect of the present invention, there is provided a vehicle with a motor in which the driving force is transmitted from the motor to the drive wheels when the driving range is selected even when the accelerator pedal is released. A motor vehicle for transmitting power, wherein when the vehicle speed is equal to or lower than a predetermined low vehicle speed, the magnitude of the driving force is switched in accordance with depression of a brake pedal, and when the brake pedal is depressed, the driving force is greater than when the brake pedal is released. A driving force reducing device for reducing the force, a motor stopping device capable of stopping the motor when the vehicle with the motor is stopped, and a brake fluid pressure capable of continuously applying the brake fluid pressure to the wheel cylinder even after the brake pedal is released. And a failure detection device that detects a failure of the brake fluid pressure retention device, By detection device and inhibits the operation of the driving force reducing device and the driving motor stopping unit when detecting a failure of the brake fluid pressure retaining apparatus. According to this motor-equipped vehicle, when the failure of the brake fluid pressure holding device is detected, the operation of the driving force reduction device and the motor stop device is prohibited. And the driving force is maintained in a large state. Further, even if a failure of the brake fluid pressure holding device is detected after the motor is automatically stopped, the motor is automatically started immediately and the driving force is increased.

Further, in the vehicle with a motor according to the third aspect of the present invention, the driving force is transmitted from the motor to the drive wheels even when the accelerator pedal is released and the driving range is selected in the transmission. A vehicle with a motor that transmits power, a motor stop device that can stop the motor when the vehicle with the motor stops, and a brake fluid pressure holding device that can continue to apply brake fluid pressure to the wheel cylinders even after the brake pedal is released. A motor-equipped vehicle comprising: a failure detection device that detects a failure of the brake hydraulic pressure holding device; prohibiting the operation of the motor stop device when the failure detection device detects a failure of the brake hydraulic pressure holding device. It is characterized by doing. According to this motor-equipped vehicle, when the failure of the brake fluid pressure holding device is detected, the operation of the motor stop device is prohibited, so that even if the brake pedal is depressed and the vehicle stops, the operation of the motor is maintained,
Maintain a large driving force. Further, even if a failure of the brake fluid pressure holding device is detected after the motor is automatically stopped, the motor is automatically started immediately to increase the driving force.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a motor vehicle according to the present invention will be described below with reference to the drawings. 1 is a system configuration diagram of a motor vehicle, FIG. 2 is a configuration diagram of a variation in which a brake hydraulic pressure holding device of the motor vehicle is provided in a brake hydraulic circuit of a hydraulic brake device, and FIG. 3 is a brake of the motor vehicle. Configuration diagram of a variation in which a hydraulic pressure holding device is provided outside a brake hydraulic circuit of a hydraulic brake device,
FIG. 4 is a cross-sectional view showing a specific structure of a brake fluid pressure holding device of a motor vehicle, and FIG. 5 is an enlarged sectional view of (a) a main part of a relief valve and a throttle portion of the brake fluid pressure holding device of FIG. (B) action diagram when forming the aperture by cutting,
(C) Operational diagram when forming aperture by pressing, FIG. 6
FIG. 7 is a configuration diagram of a variation using a proportional solenoid valve for a brake fluid pressure holding device of a motor vehicle, FIG. 7A is a logic diagram for turning on a solenoid valve of a brake fluid pressure holding device of a motor vehicle, and FIG. FIG. 8 shows that the solenoid valve of (a) the brake fluid pressure holding device of the motor vehicle is turned off.
Logic for performing F, (b) engine automatic start conditions,
FIG. 9 shows (a) the driving force and the braking force and the solenoid valve ON / O when the brake fluid pressure holding device is normal in the motor vehicle.
FF control time chart, (b) Configuration diagram of brake fluid pressure circuit when vehicle is stopped, FIG. 10 (a) Driving force and braking force of brake fluid pressure holding device without relief valve in motor vehicle with normal operation And a control time chart for ON / OFF of the solenoid valve, (b) a configuration diagram of a brake hydraulic circuit when the vehicle is stopped, and FIG. 11 shows a drive with a motor when the engine is not stopped and the brake hydraulic pressure holding device is normal. FIG. 12 is a diagram showing (a) a circuit diagram, (b) a truth table, and (c) and (b) the truth of a failure detection device for a vehicle with a motor. FIG. 13 is a control time chart of the driving force and the braking force and the solenoid valve ON / OFF when the driving force reducing device is provided in the motor vehicle and the brake fluid pressure holding device fails. Reference numeral 4 denotes a motor vehicle equipped with a driving force reducing device and a motor stopping device, and also shows a control time chart of the driving force, the braking force and the solenoid valve ON / OFF when the brake fluid pressure holding device fails, and FIG. 5 is a control time chart of the driving force and the braking force and the solenoid valve ON / OFF when the engine stop device is provided and the brake fluid pressure holding device fails.

The vehicle with a motor according to the present invention is provided with a brake fluid pressure holding device capable of applying brake fluid pressure to the wheel cylinder even when the brake pedal is released, and a failure detection for detecting a failure of the brake fluid pressure holding device. Equipment. Further, a driving force reducing device for reducing the driving force of creep when the motor is idling and the brake pedal is depressed at a predetermined low vehicle speed or lower and / or a motor stopping device capable of automatically stopping the motor while the vehicle is stopped. Is provided. A motor vehicle described in the present embodiment is a hybrid vehicle including an engine that is an internal combustion engine powered by gasoline or the like as a prime mover and a motor powered by electricity, and a belt-type continuously variable transmission as a transmission. (Hereinafter referred to as CVT).
In the vehicle with a motor of the present invention, the motor is not particularly limited, such as only the engine or only the motor as the motor. The transmission is not particularly limited as long as it is an automatic transmission such as an automatic transmission having a torque converter as the transmission.

<< System Configuration >> First, FIG.
This will be described with reference to FIG. The vehicle is powered by an engine 1
And a motor 2 and a CVT 3 as a transmission. The engine 1 includes a fuel injection electronic control unit (hereinafter referred to as FIE).
CU). The FIECU is
It is configured integrally with a management electronic control unit (hereinafter, referred to as MGECU) and provided in a fuel injection / management electronic control unit (hereinafter, referred to as FI / MGECU) 4. The motor 2 is controlled by a motor electronic control unit (hereinafter referred to as MOTECU) 5. Further, the CVT 3 is controlled by a CVT electronic control unit (hereinafter referred to as CVT ECU) 6.

Further, a drive shaft 7 on which drive wheels 8, 8 are mounted is mounted on the CVT 3. The drive wheels 8, 8 are equipped with disk brakes 9, 9 having a wheel cylinder WC (see FIG. 2) and the like. The master cylinder MC is connected to the wheel cylinders WC of the disc brakes 9, 9 via a brake fluid pressure holding device RU. The depression from the brake pedal BP is transmitted to the master cylinder MC via the master power MP. The brake switch BP detects whether the brake pedal BP is depressed or not. Further, the brake switch BSW may detect whether or not the brake pedal BP is depressed by detecting whether or not the driver puts a foot on the brake pedal BP.

The engine 1 is an internal combustion engine that uses heat energy, and drives the drive wheels 8 via a CVT 3 and a drive shaft 7. In some cases, the engine 1 is automatically stopped when the vehicle stops to prevent deterioration of fuel efficiency. For this purpose, the vehicle includes a motor stop device that stops the engine 1 when an engine automatic stop condition is satisfied.

The motor 2 has an assist mode for assisting driving of the engine 1 by using electric energy from a battery (not shown). The motor 2 has a regenerative mode in which kinetic energy due to rotation of the drive shaft 7 is converted into electric energy when assist is not required (during downhill, deceleration, etc.), and stored in a battery (not shown). It has a starting mode for starting.

The CVT 3 continuously changes the gear ratio by winding an endless belt between a drive pulley and a driven pulley, and changing the width of each pulley to change the winding radius of the endless belt. And CVT3
Connects the start clutch to the output shaft, engages the start clutch, and transmits the output of the engine 1 or the like shifted by the endless belt to the drive shaft 7 via the output gear of the start clutch. The vehicle including the CVT 3 is capable of creep running and includes a driving force reducing device that reduces the driving force of the creep. The driving force of creep is adjusted by the engaging force of the starting clutch, and has two magnitudes, a state where the driving force is large and a state where the driving force is small. The state where the driving force is large is a state where the driving force is balanced with the inclination of 5 °, and is referred to as strong creep in the present embodiment. On the other hand, a state where the driving force is small is a state where there is almost no driving force, and is called weak creep in the present embodiment. In the strong creep, the brake pedal B is released when the accelerator pedal is released (that is, in an idling state) and the travel range (D range, L range or R range) is selected by the position switch PSW.
When the stepping on P is released, the vehicle moves slowly as if crawling. In weak creep, the vehicle is stopped or at a very low speed when the vehicle speed is equal to or lower than a predetermined low vehicle speed and the brake pedal BP is depressed. The range position of the position switch PSW is selected by a shift lever. Position switch PS
The range of W is the P range used when parking and stopping, the N range which is neutral, the R range used when running backward, the D range used when running normally, and the L range used when sudden acceleration or strong engine braking is required. There is. The traveling range is a range position where the vehicle can travel, and in this vehicle, the D range, the L range, and the R range
There are three ranges. Further, when the D range is selected by the position switch PSW, the mode switch MSW can select the D mode as the normal driving mode and the S mode as the sports driving mode.

FI ECU included in FI / MG ECU 4
Controls the fuel injection amount so as to obtain the optimum air-fuel ratio, and controls the engine 1 as a whole. FIE
Information indicating the throttle opening and the state of the engine 1 is transmitted to the CU, and the CU is controlled based on each information. MGECU included in FI / MGECU 4
Controls mainly the MOTECU 5 and determines an automatic engine stop condition and an automatic engine start condition. Information indicating the state of the motor 2 is transmitted to the MGECU, and information indicating the state of the engine 1 and the like are input from the FIECU, and an instruction to switch the mode of the motor 2 is given to the MOTECU 5 based on each information. Further, information indicating the state of the CVT 3, information indicating the state of the engine 1, range information of the position switch PSW, information indicating the state of the motor 2, and the like are transmitted to the MGECU, and the engine 1 is automatically stopped based on each information. Or determine the automatic start.

The MOTECU 5 controls the motor 2 based on a control signal from the FI / MG ECU 4. FI /
The control signal from the MGECU 4 includes mode information for instructing the motor 2 to start the engine 1, assisting the driving of the engine 1 or regenerating electric energy, an output request value for the motor 2, and the like. A command is issued to the motor 2 based on the instruction. Further, information is obtained from the motor 2 and the like, and information on the motor 2 such as the amount of power generation and the capacity of the battery are transmitted to the FI / MG ECU 4.

The CVT ECU 6 controls the speed ratio of the CVT 3 and the engaging force of the starting clutch. Information indicating the state of the CVT 3, information indicating the state of the engine 1, range information of the position switch PSW, and the like are transmitted to the CVT ECU 6. To the CVT 3. Further, the CVT ECU 6 turns on (closes) / OF the solenoid valves SVA, SVB (see FIG. 2) of the brake fluid pressure holding device RU.
F (open) is controlled, and it is determined whether the creep driving force is set to a large state or a small state. In addition, the CVT ECU 6 includes a failure detection device DU for detecting a failure of the brake fluid pressure holding device RU.
The failure detection device DU also includes a drive circuit for turning on (close) / off (open) the solenoid valves SVA and SVB of the brake fluid pressure holding device RU. The configuration and the like of the failure detection device DU will be described later in detail.

The disc brakes 9, 9 are driven by wheels 8, 8,
The disk rotor, which rotates together with the disk rotor, is sandwiched between brake pads driven by a wheel cylinder WC (see FIG. 2), and a braking force is obtained by the frictional force. The brake fluid pressure of the master cylinder MC is supplied to the wheel cylinder WC via the brake fluid pressure holding device RU.

The brake fluid pressure holding device RU applies the brake fluid pressure to the wheel cylinder WC even after the brake pedal BP is released. Brake fluid pressure holding device RU
Also includes a drive circuit for driving (ON / OFF) the solenoid valves SVA and SVB of the brake fluid pressure holding device RU in the failure detection device DU in the CVT ECU 6. The configuration and the like of the brake fluid pressure holding device RU will be described later in detail. (See FIG. 2) Note that the ON / OFF state of the solenoid valve means that in the normally open solenoid valve, when the solenoid valve is ON, it means that the solenoid valve is closed and closed. That the solenoid valve opens and becomes open. " On the other hand, in the case of a normally-closed solenoid valve, when the solenoid valve is turned on, the solenoid valve is opened and becomes open, and when the solenoid valve is turned off, the solenoid valve is closed and becomes closed. The solenoid valves SVA and SVB in the present embodiment are normally open solenoid valves. Further, the drive circuit supplies a current to each coil of the solenoid valves SVA, SVB to turn on the solenoid valves SVA, SVB,
The current supply is stopped to turn off the solenoid valve.

The master cylinder MC is a device for changing the depression of the brake pedal BP to hydraulic pressure. Further, in order to assist the depression of the brake pedal BP, a master power MP is provided between the master cylinder MC and the brake pedal BP. The master power MP strengthens the braking force by applying a force such as a negative pressure of the engine 1 or a compressed air, in addition to the force of the driver pressing the brake pedal BP,
This is a device that reduces the pedaling force during braking. The brake pedal BP is provided with a brake switch BSW.
It is detected whether P is stepped on or the stepping is released.

The driving force reduction device provided in this vehicle is a CV
It is composed of a T3 and a CVT ECU 6. The driving force reduction device is used when the brake pedal BP is depressed and the vehicle speed is 5 km / h or less (at a predetermined low vehicle speed or less).
Then, the driving force of creep is reduced to change from a strong creep state to a weak creep state. The driving force reduction device is a CVT ECU
In step 6, whether or not the brake pedal BP is depressed is determined from the signal of the brake switch BSW, and whether or not the vehicle speed is 5 km / h or less is determined from the vehicle speed pulse of the CVT 3. When it is determined that the brake pedal BP is depressed and the vehicle speed is 5 km / h or less, the CVTE
A command to weaken the engagement force of the starting clutch is transmitted from the CU 6 to the CVT 3 to reduce the creep driving force. Further, C
In addition to the above two basic conditions, the VTECU 6 determines that the brake fluid temperature is equal to or higher than a predetermined value and the brake fluid pressure holding device RU is normal (the solenoid valves SVA, SVB of the brake fluid pressure holding device RU).
It is also determined that the range of the drive circuit (see FIG. 2) is normal and that the position switch PSW is in the D range, and when five conditions are satisfied, the driving force is reduced. The vehicle prevents deterioration of fuel efficiency by reducing the driving force by the driving force reduction device. In the weak creep state and when the engine 1 is stopped, the CVT ECU 6
Determine the conditions for strong creep. When the condition of the strong creep is satisfied, the CVT ECU 6 sends the CVT
A command to increase the engaging force of the starting clutch is transmitted to 3 to increase the creep driving force. Further, when the failure detection device DU detects the failure of the brake fluid pressure holding device RU, the operation of the driving force reduction device is prohibited.

The motor stopping device provided in this vehicle is an FI
/ MG ECU 4 and the like. The motor stop device is
When the vehicle is stopped, the engine 1 can be stopped automatically. The motor stop device is FI / MGECU4
Determines the automatic engine stop condition such as the vehicle speed of 0 km / h. The engine automatic stop condition will be described later in detail. When it is determined that all the engine automatic stop conditions are satisfied, the FI / MG
An engine stop command is transmitted from the ECU 4 to the engine 1,
The engine 1 is automatically stopped. The vehicle further prevents fuel consumption from deteriorating by the automatic stop of the engine 1 by the motor stop device. Note that when the engine 1 is automatically stopped by the motor stop device, the M
The GECU determines an engine automatic start condition. Then, when the engine automatic start condition is satisfied, FI / MG
The engine start command is transmitted from the ECU 4 to the MOTECU 5, and the engine 1 is transmitted from the MOTECU 5 to the motor 2.
Is transmitted, the engine 1 is automatically started by the motor 2, and a strong creep state is set.
The automatic engine start condition will be described later in detail. Further, when the failure detection device DU detects the failure of the brake fluid pressure holding device RU, the operation of the prime mover stopping device is prohibited.

Next, signals transmitted and received in this system will be described. Note that “F_” added before each signal in FIG. 1 indicates that the signal is flag information of 0 or 1, and “V_” indicates that the signal is numerical information (unit is arbitrary). "I_" indicates that the signal is information including a plurality of types of information.

The signal transmitted from FI / MG ECU 4 to CVT ECU 6 will be described. V_MOTTRQ
Is the output torque value of the motor 2. F_MGSTB
Is F_CV in the automatic engine stop condition described later.
This flag indicates whether or not all the conditions except for the five conditions of TOK are satisfied. The flag is 1 when the condition is satisfied, and is 0 when the condition is not satisfied. By the way, F_MGST
When both B and F_CVTOK switch to 1, engine 1
Is automatically stopped, and when either of the flags is switched to 0, the engine 1 is automatically started.

The signals transmitted from FI / MG ECU 4 to CVT ECU 6 and MOTECU 5 will be described. V
_NEP is the rotation speed of the engine 1.

The signal transmitted from CVT ECU 6 to FI / MG ECU 4 will be described. F_CVTOK is
The CVT 3 is in a weak creep state, the ratio (pulley ratio) of the CVT 3 is low, the oil temperature of the CVT 3 is a predetermined value or more, the brake fluid temperature is a predetermined value or more, and the brake fluid pressure holding device RU is normal (the electromagnetic pressure of the brake fluid pressure holding device RU). Valve SVA, SVB
This flag indicates whether or not the five conditions (including the normal operation of the drive circuit in FIG. 2) are satisfied. If all the five conditions are satisfied, at least one of the conditions is satisfied. Otherwise, it is 0. When the engine is stopped,
CVT3 is in weak creep condition, CVT3 ratio is low,
The condition that the oil temperature of the CVT 3 is equal to or higher than a predetermined value and the condition that the brake fluid temperature is equal to or higher than a predetermined value is maintained. That is, when the engine 1 is stopped, F_CVTOK is 1 when the brake fluid pressure holding device RU is normal, and F_CVTOK is 0 when the brake fluid pressure holding device RU is out of order.
F_CVTTO is a flag indicating whether or not the oil temperature of the CVT 3 is equal to or higher than a predetermined value. The oil temperature of the CVT 3 is C
It is estimated from the electric resistance value of the linear solenoid valve that controls the hydraulic pressure of the starting clutch of VT3. F_POSR is a flag indicating whether or not the R range has been selected in the range of the position switch PSW.
The value is 0 in cases other than the R range. F_POSDD is a flag indicating whether or not the D range is selected in the range of the position switch PSW and the D mode is selected in the mode of the mode switch MSW. 0. Note that F
The I / MG ECU 4 has a D range D mode, an R range,
If the information indicating the range and N range is not input,
It is determined that either the D range S mode or the L range has been selected.

From engine 1 to FI / MG ECU 4 and CV
The signal transmitted to the TECU 6 will be described. V_A
NP is a negative pressure value of the intake pipe of the engine 1. V_TH
Is the throttle opening. V_TW is engine 1
Is the cooling water temperature. V_TA is the intake air temperature of the engine 1. Note that the brake fluid temperature of the brake fluid pressure holding device RU disposed in the engine room is estimated based on the intake air temperature. This is because both change in relation to the temperature of the engine room.

From CVT 3 to FI / MGECU 4 and CVT
The signal transmitted to the ECU 6 will be described. V_VS
P1 is a vehicle speed pulse output from one of two vehicle speed pickups provided in CVT3. The vehicle speed is calculated based on the vehicle speed pulse.

The signal transmitted from CVT 3 to CVT ECU 6 will be described. V_NDRP is a pulse indicating the rotation speed of the drive pulley of the CVT 3. V_NDN
P is a pulse indicating the rotation speed of the driven pulley of the CVT 3. V_VSP2 is a vehicle speed pulse output from the other of the two vehicle speed pickups provided in CVT3. Note that V_VSP2 has higher accuracy than V_VSP1, and is used for calculating the slip amount of the starting clutch of the CVT3.

The signal transmitted from the MOTECU 5 to the FI / MG ECU 4 will be described. V_QBAT is the remaining capacity of the battery. V_ACTTRQ is the motor 2
, Which is the same value as V_MOTTRQ. I_MOT is information such as a power generation amount of the motor 2 indicating an electric load. In addition, all the electric power consumed by this vehicle including the motor driving electric power is generated by the motor 2.

The signal transmitted from FI / MG ECU 4 to MOTECU 5 will be described. V_CMDPWR
Is an output request value for the motor 2. V_ENGT
RQ is an output torque value of the engine 1. I_MG
Is information such as a start mode, an assist mode, and a regenerative mode for the motor 2.

From master power MP to FI / MG ECU 4
Will be described. V_M / PNP
Is a negative pressure detection value of the constant pressure chamber of the master power MP.

From position switch PSW to FI / MG
The signal transmitted to the ECU 4 will be described. Only when either the N range or the P range is selected by the position switch PSW, N or P is transmitted as position information.

The signal transmitted from CVT ECU 6 to CVT 3 will be described. V_DRHP is a hydraulic pressure command value for the linear solenoid valve that controls the hydraulic pressure of the cylinder of the drive pulley of the CVT 3. V_DNHP is CVT
This is a hydraulic command value to the linear solenoid valve that controls the hydraulic pressure of the cylinder of the driven pulley No. 3. Note that V_DRH
The gear ratio of CVT3 is changed by P and V_DNHP.
V_SCHP is a hydraulic pressure command value to the linear solenoid valve that controls the hydraulic pressure of the starting clutch of CVT3. In addition,
V_SCHP changes the engaging force of the starting clutch.

A signal transmitted from the CVT ECU 6 to the brake fluid pressure holding device RU will be described. F_SOLA
Is a flag for turning ON (close) / OFF (open) the electromagnetic valve SVA (see FIG. 2) of the brake fluid pressure holding device RU, and is 1 when it is turned ON and 0 when it is turned OFF. F_SOLB is a flag for turning ON (close) / OFF (open) the solenoid valve SVB (see FIG. 2) of the brake fluid pressure holding device RU, and is 1 when it is turned ON and 0 when it is turned OFF.

From position switch PSW to CVTEC
The signal transmitted to U6 will be described. Which position of the N range, P range, R range, D range or L range is selected by the position switch PSW is transmitted as position information.

The mode switch MSW to CVT ECU 6
Will be described. Mode switch M
Whether the D mode (normal running mode) or the S mode (sports running mode) is selected by SW is transmitted as mode information. The mode switch MSW
Is a mode selection switch that functions when the position switch PSW is set to the D range.

From the brake switch BSW to FI / MGE
The signals transmitted to the CU 4 and the CVT ECU 6 will be described. F_BKSW indicates whether the brake pedal BP is depressed (ON) or the depression is released (OFF)
The flag is 1 when the pedal is depressed, and is 0 when the pedal is released. This signal is
As described above, the flag may indicate whether the foot is placed on the brake pedal BP (ON) or not (OFF).

<< Structure of Brake Fluid Pressure Holding Device >> The brake fluid pressure holding device RU provided in the vehicle is incorporated in the brake fluid pressure circuit of the hydraulic brake device, and is adapted to reduce the speed at which the driver depresses the brake pedal BP. And a brake fluid pressure decreasing speed decreasing means for decreasing the decreasing speed of the wheel cylinder fluid pressure. Hereinafter, the brake hydraulic pressure holding device RU will be described together with the hydraulic brake device BK with reference to FIG.

[Hydraulic Brake Apparatus] First, the hydraulic brake apparatus BK will be described (see FIG. 2). The brake hydraulic circuit BC of the hydraulic brake system BK of the vehicle includes a master cylinder MC, a wheel cylinder WC, and a brake fluid pipe FP connecting the master cylinder MC and the wheel cylinder WC. Since the brake plays a very important role for safe driving, the hydraulic brake device B
K has two independent brake hydraulic circuits (BC (A), BC (B)) so that even if one system fails, the remaining system can obtain the minimum braking force. I have.

Pistons MCP, MCP are inserted into the main body of the master cylinder MC. When the driver depresses the brake pedal BP, the pistons MCP, MC
When P is pressed, pressure is applied to the brake fluid in the master cylinder MC, and mechanical force is converted to brake fluid pressure (the fluid pressure of the brake fluid). When the driver releases the brake pedal BP to release the depression, the return springs MCS, MC
With the force of S, the pistons MCP, MCP are returned to the original state, and at the same time, the brake fluid pressure is also returned to the original state. The master cylinder MC shown in FIG. 2 has a piston MC from the viewpoint of fail-safe in which two independent brake hydraulic circuits BC are provided.
This is a tandem-type master cylinder MC in which two P and MCP are arranged and the main body of the master cylinder MC is divided into two.

In order to reduce the operation force of the brake pedal BP, a master power MP (brake booster) is provided between the brake pedal BP and the master cylinder MC. The master power MP shown in FIG. 2 is of a vacuum (negative pressure) servo type, and extracts a negative pressure from an intake manifold (not shown) of the engine 1 to facilitate the driver's operation of the brake pedal BP.

The brake fluid pipe FP connects the master cylinder MC and the wheel cylinder WC, and serves as a flow path for transmitting the brake fluid pressure generated in the master cylinder MC to the wheel cylinder WC by moving the brake fluid. Further, when the brake fluid pressure of the wheel cylinder WC is higher, it serves as a flow path for returning the brake fluid from the wheel cylinder WC to the master cylinder MC. As described above, independent brake fluid circuits BC are provided, and two independent brake fluid pipes FP are provided. Brake fluid pressure circuit B composed of brake fluid pipe FP shown in FIG.
C is an X-pipe type in which one brake hydraulic circuit BC (A) brakes the right front wheel and the left rear wheel, and the other brake hydraulic circuit BC (B) brakes the left front wheel and the right rear wheel. is there. Note that the brake hydraulic circuit may be of a front-rear split type in which one brake hydraulic circuit brakes both front wheels and the other brake hydraulic circuit brakes both rear wheels, instead of the X piping system.

The wheel cylinder WC is provided for each wheel, and applies a brake fluid pressure generated by the master cylinder MC and transmitted to the wheel cylinder WC through the brake fluid pipe FP to a mechanical force (braking force) for braking the wheel. ). A piston (not shown) is inserted into the main body of the wheel cylinder WC, and the piston is pushed by a brake fluid pressure to operate a brake pad in the case of a disc brake or a brake shoe in the case of a drum brake. To create braking force to brake the wheels. In addition to the above, the brake fluid pressure of the front wheel cylinder WC and the rear wheel cylinder W
A brake fluid pressure control valve for controlling the brake fluid pressure of C is provided as needed.

[Brake fluid pressure holding device] Next, the brake fluid pressure holding device RU will be described (see FIG. 2). The brake fluid pressure holding device RU is constituted by a brake fluid pressure decreasing speed decreasing means for decreasing the decreasing speed of the brake fluid pressure in the wheel cylinder WC with respect to the decreasing speed of the driver's depression force of the brake pedal BP when the vehicle starts. You. When the driver releases the brake pedal BP when the vehicle restarts, the brake fluid pressure decreasing speed decreasing means determines the speed at which the brake fluid pressure of the wheel cylinder WC decreases (the speed at which the braking force decreases). Has a function of becoming slower than the speed at which the brake pedal BP is loosened.

The means for reducing the brake fluid pressure drop speed having such a function can be constituted by: I) providing a portion in the brake fluid pressure circuit BC which becomes a fluid resistance to the flow of the brake fluid. II) In addition to the brake hydraulic circuit BC, for example, even if the driver quickly releases the brake pedal BP by restricting the movement of the brake pedal BP itself, the brake pedal BP returns only gradually. It can also be configured by doing so. In the former case, the flow of the brake fluid itself is regulated. In the latter case, the movement of the brake pedal BP itself is restricted. In any case, the rate of decrease in the brake fluid pressure in the wheel cylinder WC can be made smaller than the rate of decrease in the driver's depression force on the brake pedal BP.

I) The brake fluid pressure reduction speed reducing means
A variation provided in the brake hydraulic circuit BC of the hydraulic brake device BK will be described. Since the hydraulic brake device BK includes two brake hydraulic circuits BC (A) and BC (B) having the same configuration, one of them is the brake hydraulic circuit BC (A). explain. In this variation, an electromagnetic valve SVA and a throttle D, and a check valve CV and a relief valve RV as necessary are provided in the brake hydraulic circuit BC (A) in order to regulate the flow of the brake fluid itself. In this variation, the solenoid valve SVA and the throttle D constitute a brake fluid pressure reduction speed reduction unit.

The electromagnetic valve SVA is turned ON (closed) / OFF (opened) by an electric signal from the CVT ECU 6, and in the ON state (closed state), shuts off the flow of the brake fluid in the brake fluid pipe FP to the wheel cylinder WC. It serves to maintain the applied brake fluid pressure. Incidentally, it is shown that the solenoid valve SVA shown in FIG. 2 is in an OFF state (open state).
By the electromagnetic valve SVA, even when the driver releases the depression of the brake pedal BP at the time of starting on a slope, the brake fluid pressure is held in the wheel cylinder WC, and the vehicle can be prevented from retreating. Note that retreating the vehicle means that the vehicle travels (downslope) in a direction opposite to the direction in which the driver tries to travel due to the potential energy (own weight) of the vehicle.

As the solenoid valve SVA, there are a normally closed type which is opened when energized (ON) and a normally open type which is closed when energized (ON), and any type of electromagnetic valve can be used. However, from the viewpoint of fail-and-safe, a normally open solenoid valve is preferable. This is because, when the power is cut off due to a failure or the like, the brake does not work with the normally closed solenoid valve, or the brake stays working. Incidentally, in normal operation, the solenoid valve SVA is
The state of N (closed state) is from the time when the vehicle stops to the time when the vehicle starts moving.
Whether VA is turned on (closed state) or turned off (opened state) will be described later.

The throttle D is connected to the master cylinder MC and the wheel cylinder W regardless of the ON / OFF state of the solenoid valve SVA.
C is conducted. Especially, solenoid valve SVA is ON (closed state)
When the driver releases the brake pedal BP or releases the brake pedal, the brake fluid trapped in the wheel cylinder WC is gradually released from the master cylinder M
It escapes to the C side and plays a role of reducing the brake fluid pressure of the wheel cylinder WC at a predetermined speed. The throttle D can be configured by providing a flow rate adjusting valve in the brake fluid pipe FP, or a portion of the brake fluid pipe FP that becomes a resistance to fluid (a portion where the cross-sectional area of the flow passage is reduced). ) May be provided.

If the driver releases or loosens the brake pedal BP due to the presence of the throttle D, even if the solenoid valve SVA is in the ON state (closed state), there is no state in which the brake is permanently applied. The braking force (braking force) gradually decreases. That is, the rate of decrease in the brake fluid pressure in the wheel cylinder WC can be made smaller than the rate of decrease in the depression force of the driver's brake pedal BP. Accordingly, even after the solenoid valve SVA is in the ON state (closed state), the braking force is sufficiently reduced after a predetermined time, and the vehicle can be restarted (starting on a slope) by the driving force of the prime mover. Also, on a downhill, the vehicle can be started only by the potential energy of the vehicle without the driver stepping on the accelerator.

In the state where the driver depresses the brake pedal BP, as long as the brake fluid pressure of the master cylinder MC is higher than the brake fluid pressure of the wheel cylinder WC, the braking force may not be reduced by the presence of the throttle D. Absent. This is because the throttle D has a function of flowing the brake fluid at a predetermined speed from a higher brake fluid pressure to a lower brake fluid pressure by a difference (differential pressure) between the brake fluid pressure of the wheel cylinder WC and the master cylinder MC. That is, as long as the driver does not release the brake pedal BP,
The brake fluid pressure of the wheel cylinder WC may increase but not decrease due to the presence of the throttle D. The throttle D may have a check valve function to prevent the flow of the brake fluid from the master cylinder MC to the wheel cylinder WC.

The speed at which the brake fluid pressure of the wheel cylinder WC is reduced is, for example, when the driver releases the brake pedal BP and depresses the accelerator pedal (change of pedal) on an uphill or the like, and the prime mover starts on a slope. Any time can be secured as long as it is possible to secure a time for preventing the vehicle from moving backward until a sufficient driving force is reached. The time required for changing the pedal to increase the driving force is usually about 0.5 seconds. When the speed of reducing the brake fluid pressure of the wheel cylinder WC is high, the solenoid valve SV
Even if A is ON (closed), brake pedal B
As soon as you release the stepping on P, the braking force is gone,
Before the vehicle has sufficient driving force, the vehicle retreats on a slope. Therefore, the purpose of facilitating starting on a slope cannot be achieved by the brake fluid pressure holding device RU. vice versa,
If the speed at which the brake fluid pressure of the wheel cylinder WC is reduced is low, the vehicle continues to be in a well-operated state even when the brake pedal BP is released, but the vehicle will not retreat. It is not preferable because extra time and power are required to secure the driving force. Also, it is difficult to easily start on a slope.

The speed at which the throttle D reduces the brake fluid pressure of the wheel cylinder WC is determined by the properties of the brake fluid and the type of the throttle D (shape such as the cross-sectional area and length of the flow path). In addition, the throttle D is set to the solenoid valve SVA or the check valve C.
It may be provided integrally with V or the like. By combining them, the number of parts and the installation space can be reduced.

The check valve CV is provided as needed. When the solenoid valve SVA is in the ON state (closed state) and the driver steps on the brake pedal BP, the check valve CV is set in the master cylinder MC. It serves to transmit the generated brake fluid pressure to the wheel cylinder WC.
The check valve CV operates effectively when the brake fluid pressure generated in the master cylinder MC exceeds the brake fluid pressure in the wheel cylinder WC, and the brake pedal B of the driver is used.
The brake fluid pressure of the wheel cylinder WC is quickly increased in response to the increase in the number of steps of P. The master cylinder MC
The brake fluid pressure of the wheel cylinder WC exceeds the brake fluid pressure of the wheel cylinder WC, the solenoid valve SVA once closed is turned off.
F (open state), the solenoid valve SVA
It is not necessary to provide the check valve CV because it is possible to cope with an increase in the number of steps of the brake pedal BP.

A relief valve RV is also provided if necessary. This relief valve RV is provided when the solenoid valve SVA is in the ON state (closed state) and the driver operates the brake pedal B
When the depression of P is released or the depression is loosened, the brake fluid confined in the wheel cylinder WC quickly escapes to the master cylinder MC side until a predetermined brake fluid pressure is reached. The relief valve RV operates when the brake fluid pressure of the wheel cylinder WC is equal to or higher than a predetermined brake fluid pressure and higher than the brake fluid pressure of the master cylinder MC. As a result, the solenoid valve SVA is turned on.
In the case of (closed state), it is possible to quickly reduce the brake fluid pressure in the wheel cylinder WC more than necessary to a predetermined brake fluid pressure. Therefore, it takes time to reduce the brake fluid pressure of the wheel cylinder WC only by the throttle D after the brake pedal BP is depressed more than necessary at the start of the slope and the driver depresses the brake pedal BP more than necessary. The problem of "unfavorable" can be solved by the relief valve RV.

The brake switch BSW detects whether or not the brake pedal BP is depressed. Based on the detected value, the CVT ECU 6 allows the solenoid valves SVA, SV
B is turned ON / OFF. Brake switch BS
W may detect whether the driver's foot is placed on the brake pedal BP.

II) The means for reducing the brake fluid pressure drop speed is
A variation provided outside the brake hydraulic circuit BC of the hydraulic brake device BK will be described with reference to FIG. This variation is, for example, a brake pedal BP
Of the brake pedal BP.

The return restricting means includes a return restricting cylinder RC,
A fixing jig FJ for fixing this to the brake pedal BP and the vehicle, an electromagnetic valve SV and a throttle D, and a check valve CV and a relief valve RV as required are provided. This configuration is almost the same as the variation in which the brake fluid pressure reduction speed reducing means is provided in the brake fluid pressure circuit BC. The brake fluid pressure reduction speed reducing means is configured by a return regulating cylinder RC, a solenoid valve SV, a throttle D, and the like.

A piston RCP is inserted into the body of the return regulating cylinder RC. Then, the fixing jig FJ fixes, for example, the return control cylinder RC body side to the vehicle and the piston RCP side to the brake pedal BP. As a result, when the driver depresses the brake pedal BP, fluid such as air inside the return control cylinder RC is discharged to the outside (atmosphere). Conversely, when the brake pedal BP is released, the brake pedal BP returns to its original position. Fluid such as air flows into the return control cylinder RC.
The above-mentioned solenoid valve SV and the like are connected to the return control cylinder RC, and the return speed of the brake pedal BP is controlled by restricting the flow rate of the fluid flowing into the return control cylinder RC after the brake pedal BP is released. .
The operation and role of the solenoid valve SV and the throttle D are the same as those of the variation in which the above-described brake fluid pressure reduction speed reducing means is provided in the brake fluid pressure circuit BC of the hydraulic brake device BK.

<< Specific Structure of Brake Fluid Pressure Holding Device >> Next, a specific structure of the brake fluid pressure holding device RU will be described with reference to FIG. Brake hydraulic pressure holding device R shown in FIG.
U has a structure in which the solenoid valve SV, the throttle D, the check valve CV, and the relief valve RV are combined and integrated.
That is, when the brake hydraulic pressure holding device RU is provided in the brake hydraulic circuit BC of the hydraulic brake device BK, the configuration shown in FIG. 2 is obtained. In this structure,
The throttle D is provided integrally with a part of the relief valve RV. The brake fluid pressure holding device of this structure
It can be provided inside the brake hydraulic circuit BC as shown in FIG. 2, or can be provided outside the brake hydraulic circuit BC as shown in FIG.

The solenoid valve SV is provided with a brake fluid pressure holding device RU.
Located at the top of. When a current flows through the coil part SVc of the solenoid valve SV, a magnetic force is generated, and the shaft SVs moves up and down due to the magnetic force. A ball SVb is attached to the lower end of the shaft SVs, and the ball SVb moves up and down as the shaft SVs moves up and down to open and close the valve portion SVv. Energization of the solenoid valve SV is performed by two electrodes SVe and SVe.
Is done through Reference sign SVf is an urging spring that urges the shaft SVs upward. Solenoid valve SV is OFF
In the state (open state), the brake fluid from the master cylinder MC is supplied to the master cylinder side joint Jm.
From the brake fluid pressure holding device RU through the main flow path Cm
(The main flow path Cm, the annular flow path Cr, and the main flow path Cm), the valve portion SVv in the open state, the main flow path Cm, and the wheel cylinder side joint Jw to reach the wheel cylinder WC. On the other hand, when the brake fluid flows from the wheel cylinder WC to the master cylinder MC, the reverse route is followed. The main flow path Cm of the brake fluid is shut off by the solenoid valve SV, and the brake fluid pressure is held in the wheel cylinder WC.

The check valve CV is a valve portion SV of the solenoid valve SV.
It is located near the lower part of v. When the driver increases the brake pedal BP when the solenoid valve SV is in the ON state (closed state), the brake fluid from the master cylinder MC enters the brake fluid pressure holding device RU from the master cylinder side joint Jm, and the main flow It passes through the path Cm, the annular flow path Cr, the valve portion CVv of the check valve CV, the main flow path Cm, and the wheel cylinder side joint Jw to reach the wheel cylinder WC. The check valve CV opens when the master cylinder M
This is the case where the brake fluid pressure of C is higher than the brake fluid pressure of the wheel cylinder WC, and the differential pressure, which is the difference between the two, is higher than the operating pressure of the check valve CV. The operating pressure of the check valve CV is the ball CVb of the check valve CV.
Is set by the pressing force of the spring CVs for pressing.
The member indicated by reference symbol CVc is a ball that closes a communication hole with the annular flow path Cr. The annular flow path Cr is a ring-shaped brake fluid flow path arranged so as to surround the check valve CV from below the valve portion SVv of the solenoid valve SV. Even when the solenoid valve SV is in the ON state (closed state), the check valve CV allows the driver to increase the brake force by increasing the brake pedal BP.

[0066] The relief valve RV is located below the brake fluid pressure holding device RU. The upper part of the relief valve RV is connected to the annular flow path Cr via the branch oil passage Cb. Therefore, when the solenoid pedal SV is in the ON state (closed state) and the driver depresses the brake pedal BP which has been strongly depressed, the brake fluid of the wheel cylinder WC is released from the wheel cylinder side joint Jw, the main flow path Cm, and the branch. Flow path Cb, valve portion RVv of relief valve RV, branch flow path Cb,
It passes through the annular flow path Cr, the main flow path Cm, and the master cylinder side joint Jm to reach the master cylinder MC. The reason why the relief valve RV opens is that the brake fluid pressure of the wheel cylinder WC is higher than the brake fluid pressure of the master cylinder MC, and the differential pressure that is the difference between the two brake fluid pressures is the operating pressure (relief pressure) of the relief valve RV. If it is higher. The relief pressure is set by the pressing force of a spring RVs pressing the ball RVb of the relief valve RV. Even when the solenoid valve SV is ON (closed state), the brake pedal BP which the driver strongly depressed by this relief valve RV
Is released, the brake fluid pressure of the wheel cylinder WC can be reduced to the set pressure of the relief valve RV at a stretch.

The throttle D is provided in the valve portion RVv of the relief valve RV as a small groove (details will be described later), and this groove is provided for the ball RVb even when the relief valve RV is in the closed state.
Will not be blocked by Therefore, the solenoid valve SV,
Regardless of the open / close state of the check valve CV and the relief valve RV, the master cylinder MC and the wheel cylinder WC are always in a state of conduction through the throttle D. When the brake fluid pressure of the wheel cylinder WC is higher than the brake fluid pressure of the master cylinder MC, the brake fluid is supplied to the wheel cylinder side joint Jw, the main flow path Cm, and the branch flow path C.
b, the throttle D provided in the valve portion RVv of the relief valve RV, the branch flow path Cb, the annular flow path Cr, the main flow path Cm, the master cylinder side joint Jm, and the master cylinder MC
Reach In which direction the throttle fluid flows through the throttle D is governed only by the difference between the brake fluid pressures of the master cylinder MC and the wheel cylinder WC. The amount of the brake fluid that passes through the throttle D depends on the cross-sectional area of the flow channel of the throttle D, the length of the flow channel, the difference (differential pressure) between the brake fluid pressures of the master cylinder MC and the wheel cylinder WC, and the viscosity of the brake fluid. Change. When the driver loosens or opens the brake pedal BP by the small groove D, the brake fluid flows from the wheel cylinder WC to the master cylinder MC even when the solenoid valve SV is ON (closed). Gradually decrease.

Referring to FIG. 5, the relief valve RV and the throttle D will be further described in detail. The relief valve RV is a normally-closed valve that presses a ball RVb against a valve portion RVv formed in a tapered shape to shut off a brake fluid flow path. It is the spring RVs that presses the ball RVb. In this configuration, when the brake fluid pressure on the wheel cylinder WC side is higher than the brake fluid pressure on the master cylinder MC side and the pressure difference between the two becomes greater than the pressing force of the spring RVs, the ball RVb , And the relief valve RV is opened. And when the differential pressure becomes smaller than the pressing force of the spring RVs,
The lifted ball RVb is pressed by the valve portion RVv, and the relief valve RV is closed.

The throttle D is provided in a part of the tapered valve portion RVv as a small V-shaped groove having a substantially V-shaped cross section along the flow of the brake fluid. As described above, even when the relief valve RV is in the closed state, the throttle D is not blocked by the ball RVb, so that the brake fluid is always conducted. The flow of the brake fluid indicated by the arrow in FIG. 5A is a flow when the brake fluid pressure on the master cylinder MC side is low. The shape of the cross section of the throttle D may be a U-shape or the like. If the driver releases the depression of the brake pedal BP, a specific shape can be used as long as the brake fluid can flow to the master cylinder MC side at a predetermined speed. It is not limited to the shape.

As shown in FIG. 5B, the aperture D as a V-groove can be manufactured by cutting a tapered valve portion RVv with a cutting tool CB. Further, as shown in FIG. 5 (c), it can be manufactured by pressing the jig JB against the tapered valve portion RVv. FIG.
Arrows (b) and (c) indicate the directions in which the blade CB and the jig JB are moved.

The V-groove can be formed by pressing, for example, after pressing a wedge-shaped jig JB (grooving) and then pressing (coining) a spherical jig JB ′. (See FIGS. 4 (c1) and (c2)). In the case of this manufacturing method, the return RE generated by the preceding groove processing is flattened by the later coining.
In the case of pressing, since the aperture D is produced only by deformation of the material, there is an advantage that cutting chips are not generated. 4 and 5, the throttle D is provided integrally in the relief valve RV. However, the throttle D may be provided integrally in the solenoid valve SV or the check valve CV. In addition,
The brake fluid pressure holding device RU in FIG. 4 has a structure in which solenoid valves SV and the like are combined to form a single unit.
Is not limited to the structure of the united brake fluid pressure holding device RU. Even in the brake fluid pressure holding device RU having a structure in which the solenoid valve SV, the check valve CV, etc. are provided separately without being combined, the throttle D is provided with the relief valve RV.
It can be configured as a V-groove provided in the like.

<< Modifications of the Brake Fluid Pressure Holding Device >> Various modifications of the brake fluid holding device RU are conceivable. For example, the electromagnetic valves SV,
Instead of using the throttle D and the relief valve RV, it is also possible to use a proportional solenoid valve LSV having these functions in one solenoid valve (see FIG. 6). In FIG.
The brake fluid pressure gauge indicated by G is the master cylinder MC
And the brake fluid pressure between the proportional solenoid valve LSV is measured. This measured value is taken into the CVT ECU 6 and subjected to arithmetic processing. Then, the proportional solenoid valve LSV adjusts the flow rate of the brake fluid (brake fluid pressure decreasing speed) by changing the opening degree of the valve based on a command from the CVT ECU 6. The two proportional solenoid valves LSV, LSV shown in FIG. 6 are both open. According to this configuration, since the proportional solenoid valve LSV plays the role of a throttle and a relief valve, the number of parts can be reduced.

Also in this modification, the check valve CV is provided as needed. The master cylinder MC
Is configured to increase the opening of the proportional solenoid valve LSV when the brake fluid pressure exceeds the brake fluid pressure of the wheel cylinder WC, it is possible to cope with an increase in the brake pedal BP only with the proportional solenoid valve LSV. be able to.

<< Basic Operation of Brake Fluid Pressure Holding Device >> A basic operation of the brake fluid pressure holding device RU will be described with reference to FIG. (Stop / Start on Uphill) For example, when waiting for a signal on an uphill, the driver depresses the brake pedal BP so that the vehicle does not retreat under its own weight. As a result, the brake fluid in the master cylinder MC is compressed, and the brake fluid pressure is increased. This brake fluid pressure is accompanied by the flow of the brake fluid, and the brake fluid pipe FP and the solenoid valves SVA,
The power is transmitted to the wheel cylinder WC through the SVB, converted into a braking force for braking the wheels, and the vehicle stops on a slope.

C for integrally controlling the electric system of the vehicle, etc.
The VTECU 6 determines conditions such as that the vehicle is stopped, turns on the solenoid valves SVA and SVB (closed state), and holds the brake fluid pressure in the wheel cylinder WC. The CVT ECU 6 does not need to determine whether the place where the vehicle is stopped is on a slope. The solenoid valves SVA, S
Even if VB is in ON state (closed state), check valve C
If V and CV are provided, the driver can use the brake pedal B
By stepping on P, this check valve C
The braking force can be increased through V and CV.

Next, the driver releases the depression of the brake pedal BP and depresses an accelerator pedal (not shown) in order to start on a slope. In this operation, the solenoid valves SVA,
Since the SVB is in the ON state (closed state), even if the driver releases the brake pedal BP, the vehicle does not retreat on the slope. However, the brake fluid pressure of the brake fluid in the wheel cylinder WC gradually decreases through the throttles D and D. On the other hand, when the driver depresses the accelerator pedal, the driving force increases. Then, when the driving force is greater than the sum of the force for stopping the advance on the slope and the gradually decreasing braking force, the vehicle starts on the slope. Apertures D, D allow the driver to
If the vehicle does not retreat on the sloping road for about 0.5 seconds after releasing the depression of P, the driver can easily start the sloping road. Some drivers may depress the brake pedal BP more than necessary. In such a case, if the relief valves RV, RV are provided, the brake fluid pressure in the wheel cylinder WC is reduced to a predetermined brake fluid pressure (relief pressure) by releasing or loosening the brake pedal BP. Since it can be reduced all at once, a quick slope start can be performed.

After starting on the slope, the solenoid valve SV
When A and SVB are in the ON state (closed state), the brake is dragged, which is not preferable. For this reason, the solenoid valves SVA and SVB are turned off when the driver performs the start operation.
(Open state). Specifically, in an automatic transmission vehicle, it is preferable to perform control to turn off the solenoid valve SV (open state) when the accelerator pedal is depressed. As a fail-and-safe action, the solenoid valves SVA and SVB that have stopped the flow of the brake fluid are turned off (open state) after a predetermined time (for example, after 2 to 3 seconds) since the depression of the brake pedal BP is released. )
May be controlled. The depression and release of the brake pedal BP are detected by the brake switch BSW. Furthermore, in order to eliminate unnecessary brake dragging, when the vehicle speed becomes equal to or higher than a predetermined speed (for example, 5 km / h), control for turning off the solenoid valves SVA and SVB (open state) may be performed. Good.

(Stop / Start on Downhill) When stopping on a downhill, the driver depresses the brake pedal BP as in the case of the uphill to stop. CVT ECU 6 is
The conditions such as that the vehicle is stopped are determined, and the solenoid valves SVA and SVB are turned on (closed state) to maintain the brake fluid pressure in the wheel cylinder WC, as in the case of an uphill.

Next, the driver releases the brake pedal BP in order to go down the hill (to start).
Normally, in the case of a downhill, the driver tries to go down the hill using the vehicle's own weight without depressing the accelerator pedal. According to the above-mentioned brake fluid pressure holding device RU, even if the solenoid valves SVA, SVB are in the ON state (closed state) by the throttles D, D, the brake pedal BP is released or the brake pedal BP is released, and the brake is released. Power gradually weakens. Therefore, the vehicle can be started without depressing the accelerator pedal, as in the case of starting the vehicle downhill in a normal vehicle.

According to the brake fluid pressure holding device RU, the vehicle can easily start even on an uphill where starting is difficult. Also, there is no problem in starting the vehicle even on a downhill or a flat place. Further, there is no need for the CVT ECU 6 to determine whether the vehicle is stopped on a slope or a flat place, and there is no need for means for detecting whether or not the vehicle is on a slope.

<< Others >> In a vehicle equipped with a traction control system capable of generating brake fluid pressure regardless of brake pedal depression, the brake fluid pressure in the wheel cylinder when the brake pedal is released after the vehicle stops. It is also possible to configure the brake fluid pressure holding device by performing control by a traction control system. In this case, however, the traction control is performed while detecting the decreasing speed of the brake fluid pressure (the decreasing speed of the depression force of the brake pedal) as in the brake fluid pressure holding device RU using the proportional solenoid valve LSV described with reference to FIG. It is necessary to control the brake fluid pressure in the wheel cylinder by the system. Similarly, even in a vehicle equipped with an anti-lock brake system capable of controlling the brake fluid pressure in the wheel cylinder when the brake pedal is depressed, the brake fluid pressure in the wheel cylinder is controlled by the anti-lock brake system. Thus, the brake fluid pressure holding device can be configured.

<< Case where brake fluid pressure is maintained >>
A case where the brake fluid pressure is held by the brake fluid pressure holding device RU will be described. The brake fluid pressure is maintained
As shown in FIG. 7A, this is the case where I) the driving force of the vehicle is in a weak creep state, and II) the vehicle speed is 0 km / h. When this condition is satisfied, two solenoid valves SV
A and SVB are both turned on to close, and the brake fluid pressure is held in the wheel cylinder WC. Note that the driving force enters the weak creep state (F_WCRON = 1) after the weak creep command (F_WCRP = 1) is issued. The reduction of the driving force from the strong creep state to the weak creep state is performed by a driving force reduction device.

I) The condition of "weak creep state"
On a slope, the brake pedal BP is strong enough for the driver.
Is to be stepped on. That is, in the strong creep state, the driver has a driving force so that the vehicle does not move backward even on a slope having a slope of 5 degrees.
The vehicle can be stopped on a slope without strongly stepping on the vehicle. Therefore, the driver may depress the brake pedal BP only weakly. In such a case, if the solenoid valves SVA and SVB are turned ON (closed state) and the engine 1 is stopped, the vehicle retreats on a slope.

II) The condition that the "vehicle speed is 0 km / h" is because the vehicle cannot be stopped at an arbitrary position if the solenoid valves SVA and SVB are turned on (closed) during running. by.

[I. Conditions under which a weak creep command is issued)
The weak creep command (F_WCRP) is, as shown in FIG. 7A, 1) that the brake fluid pressure holding device RU is normal, 2) that the brake fluid temperature is equal to or higher than a predetermined value (F_BKT).
O), 3) that the brake pedal BP is depressed and the brake switch BSW is ON (F_BKSW);
4) The vehicle speed is 5 km / h or less (F_V
S), 5) Issued when all of the conditions that the position switch PSW is in the D range (F_POSD) are satisfied. These conditions are determined by the driving force reduction device. The driving force is set to be in the weak creep state in addition to the reason that the driver strongly depresses the brake pedal BP as described above, and also the reason that fuel efficiency is improved.

1) The reason why the weak creep command is not issued when the brake fluid pressure holding device RU is not normal is, for example,
If a weak creep command is issued and the weak creep condition occurs when there is an abnormality such as the solenoid valves SVA and SVB not being turned on (closed state), the brake fluid pressure is not held in the wheel cylinder WC. This is because when the driver releases the brake pedal BP, the braking force is lost at a stretch and the vehicle retreats on a slope. In this case, by maintaining the strong creep state, the vehicle is prevented from retreating on a sloping road and the hill starts (uphill).

2) The reason why the weak creep command is not issued when the brake fluid temperature is lower than the predetermined value is that when the brake fluid temperature is low, the brake fluid pressure holding device RU is operated to activate the solenoid valves SVA, SVA.
When VB is turned ON (closed state), when the depression of the brake pedal BP is partially released, the wheel cylinder WC
This is because there is a problem that the rate of decrease of the brake fluid pressure becomes extremely slow. That is, if the brake pedal BP is only loosened, the brake switch BSW remains ON, and the solenoid valves SVA and SVB remain ON forever.
In the state (closed state). Accordingly, the brake fluid is discharged only through the narrow throttle D. However, since the brake fluid has a high viscosity when the temperature is low, the brake fluid does not flow at a desired speed, so that the brake force is maintained in a strong state forever. This is because they will be left behind. As described above, when the brake fluid temperature is low, the weak creep state is prohibited, the strong creep state is maintained, and retreat on a slope is prevented. By the way, if the strong creep state is maintained, the brake fluid pressure holding device RU does not operate and the solenoid valve S
VA and SVB do not turn on and do not close. .
In the case of the brake fluid pressure holding device RU having no throttle D in the brake fluid pressure circuit BC, for example, the brake fluid pressure holding device RU having a configuration using a proportional solenoid valve LSV capable of changing the opening of the valve. In this case, the importance of controlling the temperature of the brake fluid is not so high. Also, in the case of the brake fluid pressure holding device RU configured to delay the return of the brake pedal BP itself, the management of the temperature of the brake fluid is not so important. Therefore, even when the brake fluid temperature is low to some extent, a weak creep command can be issued.

3) The reason why the weak creep command is not issued when the brake pedal BP is not depressed (F_BKSW) is that the driver does not want to at least reduce the driving force.

4) The reason why the weak creep command is not issued when the vehicle speed is 5 km / h or more is that the reverse driving force from the driving wheels 8, 8 is transmitted to the engine 1 or the motor 2 via the starting clutch, and This is because the brake may be applied or regenerative power generation by the motor 2 may be performed.

5) Unlike the case where the position switch PSW is in the D range, the weak creep command is not issued when the position switch PSW is in the R range or the L range. This is for facilitating garage entry due to strong creep running.

Whether or not the vehicle is in the weak creep state is determined based on the hydraulic pressure command value for the starting clutch of the CVT 3. The flag F_WCRPON in the weak creep state continues until the next strong creep state.

[II. Automatic Stopping Condition of Engine] In order to further improve fuel efficiency, the engine 1 is automatically stopped when the vehicle is stopped. This condition will be described. When all of the following conditions are satisfied, the engine stop command (F
_ENGOFF) is issued and the engine 1 automatically stops (see FIG. 7B). The automatic stop of the engine 1 is performed by a motor stop device. Therefore, the following engine automatic stop condition is determined by the motor stop device.

1) The position switch PWS is in the D range and the mode switch MSW is in the D mode (hereinafter, this state is referred to as "D range D mode");
In modes other than the D range D mode, the engine 1 does not stop unless the ignition switch is turned off. For example, when the position switch PSW is in the P range or the N range, a command to automatically stop the engine 1 is issued and the engine 1 is stopped. This is because it may be. When the position switch PSW is in the D range and the mode switch MSW is in the S mode (hereinafter, this state is referred to as “D range S mode”), the engine 1 is not automatically stopped. The driver is
This is because in the D range S mode, it is expected that the vehicle can be started quickly. When the position switch PSW is in the L range or the R range, the engine 1
The automatic stop is not performed because it is troublesome if the engine 1 automatically stops frequently when the vehicle is put in a garage or the like.

2) The brake pedal BP is depressed and the brake switch BSW is ON; this is to call the driver's attention. When the brake switch BSW is ON, the driver has put his foot on the brake pedal BP. Therefore, even if the driving force is lost due to the automatic stop of the engine 1 and the vehicle starts to retreat on the slope, the driver can easily increase the brake pedal BP.

3) After starting the engine 1, once the vehicle speed is 5km
/ H or more; This is for facilitating garage out of the garage during creep running. This is because it is troublesome if the engine 1 is automatically stopped every time the vehicle 1 is stopped due to a switching operation when the vehicle is taken in and out of the garage.

4) The vehicle speed is 0 km / h because no driving force is required if the vehicle is stopped. 5) Battery capacity is equal to or greater than a predetermined value; Engine 1
This is to prevent a situation where the engine 2 cannot be restarted by the motor 2 after the stop. 6) Electric load is not more than a predetermined value; this is to ensure supply of electricity to the load.

7) The negative pressure in the constant pressure chamber of the master power MP is equal to or higher than a predetermined value; when the engine 1 is stopped with the negative pressure in the constant pressure chamber being small, the negative pressure in the constant pressure chamber is introduced from the intake pipe of the engine 1. Therefore, the negative pressure in the constant-pressure chamber is further reduced, the amplification of the depression force when the brake pedal BP is depressed is reduced, and the effectiveness of the brake is reduced.

8) The accelerator pedal is not depressed; the driver does not want to increase the driving force, and there is no problem even if the engine 1 is stopped.

9) The CVT 3 is in a weak creep state; this is for preventing the vehicle from retreating even after the engine 1 is stopped by forcing the driver to depress the brake pedal BP strongly. That is, when the engine 1 is started, retreat on a slope is prevented by the sum of the braking force and the creep force. For this reason, in the strong creep state, the driver may increase or decrease the depression of the brake pedal BP, and may depress only weakly instead of depressing strongly.

10) The ratio of the CVT 3 is low; if the ratio (pulley ratio) of the CVT 3 is not low, the vehicle 1 may not be able to start smoothly, and the engine 1 is not automatically stopped. Therefore, for a smooth start,
When the ratio of the CVT 3 is low, the engine 1 is automatically stopped.

11) The water temperature of the engine 1 is equal to or higher than a predetermined value; this is because the automatic stop / automatic start of the engine 1 is preferably performed while the engine 1 is stable. If the water temperature is low, the engine 1 may not restart in a cold region.

12) The oil temperature of the CVT 3 is equal to or higher than a predetermined value. When the oil temperature of the CVT 3 is low, the actual rise of the hydraulic pressure of the starting clutch is delayed, and the engine 1 starts to be in a strong creep state. Since it takes time until the vehicle moves backward on a slope, the stop of the engine 1 is prohibited.

13) The temperature of the brake fluid is equal to or higher than a predetermined value; if the temperature of the brake fluid is low, the fluid resistance at the throttle D increases, causing unnecessary brake dragging. For this reason, the brake fluid pressure holding device RU
Does not work. Therefore, the automatic stop and the weak creep state of the engine 1 are prohibited, and the strong creep causes
Prevents retreat on slopes. In addition, R in the brake hydraulic circuit
Brake fluid pressure holding device RU having a configuration in which throttle D is not provided in U
In the case of, for example, the brake fluid pressure holding device R configured to use the proportional solenoid valve LSV capable of changing the opening of the valve
In the case of U, the importance of controlling the temperature of the brake fluid is not so high. Also, in the case of the brake fluid pressure holding device RU configured to delay the return of the brake pedal PB itself, the management of the temperature of the brake fluid is not so important. Therefore, even when the brake fluid temperature is low to some extent, the engine automatic stop command can be issued.

14) The brake fluid pressure holding device RU is normal; if the brake fluid pressure holding device RU is abnormal, the brake fluid pressure may not be able to be held. To prevent the vehicle from moving backward on a slope. Therefore, when there is an abnormality in the brake fluid pressure holding device RU, the automatic stop of the engine 1 is not performed. On the other hand, when the brake fluid pressure holding device RU is normal, there is no problem even if the engine 1 is automatically stopped.

<< When the holding of the brake fluid pressure is released >>
Solenoid valves SVA, SVB once turned on (closed state)
8) As shown in FIG. 8A, I) the brake pedal BP
If the specified delay time has elapsed after the release of the stepping-in, II)
If the driving force is in a strong creep condition, III) The vehicle speed is 5
When the speed becomes more than km / h, it is turned off (open state) when any of the conditions is satisfied, and the holding of the brake fluid pressure is released.

I) When the brake pedal BP is released (the brake switch BSW is turned off)
When it becomes FF), counting starts. The delay time is about 2 to 3 seconds, and the solenoid valves SVA and SVB are turned OFF (open state) as a fail-and-safe action to eliminate brake dragging.

II) The solenoid valves SVA and SVB are turned off (opened) when the driving force is in a strong creep state. In the strong creep state, the vehicle can be stopped against a 5 ° slope. This is because the provision of the driving force makes it unnecessary to hold the brake fluid pressure in the wheel cylinder WC to prevent the vehicle from moving backward. The strong creep state is set after the strong creep command (F_SCRP) is issued, but the strong creep command is issued when the brake pedal BP is released in the D range (when the brake switch BSW is OFF). Be emitted.

III) When the vehicle speed exceeds 5 km / h, the solenoid valves SVA and SVB are turned off (open state) because of a fail-and-safe action for eliminating unnecessary brake dragging.

[Automatic Engine Start Condition] After the engine 1 is automatically stopped, the engine 1 is automatically started in the following cases. This condition will be described (see FIG. 8B). The engine 1 starts automatically when any of the following conditions is satisfied.

1) D range D mode and release of brake pedal BP is released; it is determined that the driver's start operation has been started, so engine 1 automatically starts.

2) When the mode is switched to the D range S mode: When the engine 1 is automatically stopped in the D range D mode and then switched to the D range S mode, the engine 1 automatically starts. This is because the driver expects a quick start in the D range S mode, and automatically starts the engine 1 without waiting for the brake pedal BP to be released.

3) When the accelerator pedal is depressed;
This is because the driver expects the driving force of the engine 1.

4) When the range is switched to the P range, N range, L range, or R range: When the engine 1 is automatically stopped in the D range D mode and then switched to the P range, the engine 1 automatically starts. If the engine 1 does not start automatically when switching to the P range or N range, the driver may think that the ignition switch has been turned off,
This is because it is not necessary to turn off the ignition switch, and the vehicle may leave the vehicle as it is, which is not preferable from the viewpoint of fail-safe. In order to prevent such a situation, the engine 1 is restarted. The reason why the engine 1 is automatically started when the range is switched between the L range and the R range is that it is determined that the driver intends to start.

5) When the battery capacity is equal to or less than a predetermined value;
Is not automatically stopped, but the battery capacity may be reduced even after the engine 1 is automatically stopped once.
In this case, the engine 1 is automatically started for the purpose of charging the battery. The predetermined value is set to a value higher than the limit battery capacity at which the engine 1 cannot be automatically started when the battery capacity is further reduced.

6) When the electric load exceeds a predetermined value;
For example, if an electric load such as lighting is operating, the battery capacity is rapidly reduced, and the engine 1 cannot be restarted. Therefore, when the electric load is equal to or more than the predetermined value regardless of the battery capacity, the engine 1 is automatically started.

7) When the negative pressure of the master power MP falls below a predetermined value: When the negative pressure of the master power MP decreases, the braking force of the brake decreases, and the engine 1 is restarted to secure this. .

8) When the brake fluid pressure holding unit RU is out of order; When the solenoid valves SVA, SVB and the drive circuit of the solenoid valves are out of order, the engine 1 is started to create a strong creep state. If a failure is detected in the brake fluid pressure holding device RU including the drive circuit of the solenoid valve after the engine 1 is automatically stopped, the brake fluid pressure is maintained when the brake pedal BP is released when the vehicle starts moving. In some cases, the engine 1 is automatically started when a failure is detected in order to set a strong creep state. That is, the vehicle is prevented from moving backward in the strong creep state, and the vehicle is easily started on a slope. The failure detection of the brake fluid pressure holding device RU is performed by the failure detection device DU.

<< Control Time Chart when the Brake Fluid Pressure Holding Apparatus is Normal (1) >> Next, what kind of control is performed in the vehicle having the above-mentioned system configuration, for example, during traveling, is shown in FIG. This will be described with reference to FIG. Note that the position switch PSW and the mode switch MSW of the vehicle are D
It is not changed in the mode D range. Further, the brake fluid pressure holding device RU has a configuration including a relief valve RV. Here, the control time chart in the upper part of FIG. 9A is a diagram showing the increase and decrease of the driving force and the braking force of the vehicle in time series. In the drawing, a thick line indicates the driving force, and a thin line indicates the braking force. The lower control time chart in FIG. 9A shows ON (closed) / OFF of the solenoid valves SVA and SVB.
It is the figure which showed (open). FIG. 9B is a diagram showing a state of the brake hydraulic circuit BC at the time of stoppage, and shows the state of the solenoid valve SV.
(SVA, SVB) is in the ON state (closed state).

First, in FIG. 9A, when the vehicle is running,
When the driver depresses the brake pedal BP (brake switch BSW [ON]), the braking force increases. When the driver depresses the brake pedal BP, the driver releases the depression of the accelerator pedal, so that the driving force decreases and eventually goes into a strong creep state (normal idling state). Then, when the brake pedal BP is continuously depressed and the vehicle speed becomes 5 km / h or less, a weak creep command (F_WCRP) is issued, the vehicle enters a weak creep state (F_WCRPON), and the driving force further decreases.

When the vehicle speed becomes 0 km / h, the solenoid valves SVA and SVB are turned on (closed state), the engine 1 is automatically stopped (F_ENGOFF), and the driving force is lost. At this time, the solenoid valves SVA and SVB are ON
(Closed state), the brake fluid pressure is held in the wheel cylinder WC. Further, since the engine 1 stops after passing through the weak creep state, the driver depresses the brake pedal BP so strongly that the vehicle does not retreat on the slope. Therefore, even if the engine 1 is automatically stopped, the vehicle does not move backward (reverse restraining force). Even if the vehicle retreats, the vehicle is prevented from retreating only by slightly increasing the brake pedal BP. Since the driver is in the state where the brake pedal BP is depressed (the state where the foot is put on the brake pedal BP), the driver can easily increase the brake pedal BP without panic. The reason why the engine 1 is automatically stopped is to improve fuel efficiency and eliminate generation of exhaust gas. Conditions under which the driving force becomes weak creep,
The conditions under which the solenoid valves SVA and SVB are turned on (closed state) and the conditions under which the engine 1 is automatically stopped are as described above with reference to FIG.

Next, the driver releases the brake pedal BP in preparation for restart. The driver sets the brake pedal B higher than the set pressure (relief pressure) of the relief valve RV.
When the brake pedal P is depressed, the relief valve R is released by releasing the brake pedal BP as shown in FIG.
V operates to reduce the braking force to the relief pressure in a short time. By this relief valve RV, even when the driver depresses the brake pedal BP more than necessary, the vehicle can quickly start on a slope.

When the brake pedal BP is completely released (brake switch BSW [OFF]), an engine automatic start command (F_ENGON) is issued. Start automatically. Then, the driving force increases and a strong creep state occurs (F_SCRPON). The time from when the brake pedal BP is released (when the brake switch BSW is turned off) until the strong creep state is reached is about 0.5 second. During this time, the solenoid valves SVA, SV
Since B is still in the ON state (closed state), the brake fluid can only pass through the fine throttle D
Since the vehicle cannot move to the C side, the braking force decreases only gradually, and the vehicle is prevented from moving backward.

Then, in the strong creep state (F_SCRPO
In the case of N), a driving force capable of resisting a slope is generated, so that the braking force does not hinder the start of the vehicle, and in order to eliminate unnecessary dragging of the brake,
The solenoid valves SVA and SVB in the ON state (closed state) are turned off.
F (open state), the brake fluid pressure of the wheel cylinder WC is reduced at once, and the braking force is eliminated. Thereafter, the driving force increases due to further depression of the accelerator pedal, and the vehicle accelerates. Conditions under which the driving force is in a strong creep state, solenoid valves SVA and SVB are OFF (open state)
Are as described above with reference to FIG.

Note that, in the line indicating the braking force in the upper diagram of FIG. 9A, a virtual line extending obliquely downward to the right from the “relief pressure” portion indicates a case where the brake fluid pressure is not maintained.
In this case, the braking force decreases and disappears without being delayed by the decrease in the depression force of the brake pedal BP, so that it is not easy to start on a slope. Also, in the line indicating the braking force in the upper diagram of FIG. 9A, the solenoid valves SVA, SV
The imaginary line gradually lowering from the part where B is OFF (open state) to the lower right is the solenoid valves SVA and SVB with OF.
This shows a situation in which the braking force is reduced when F (open state) is not attained. When the braking force is reduced as shown by the imaginary line, the brake is dragged, which is not preferable. FIG.
(B) V_BKDLY in the lower diagram indicates a delay time. After the delay time has elapsed, the solenoid valves SVA and SVA are used as a fail-and-safe action regardless of the situation.
VB is turned off (open state).

<< Control Time Chart when the Brake Fluid Pressure Holding Apparatus is Normal (2) >> Next, with reference to FIG. 10, what kind of control is performed when the vehicle is running will be described. The position switch PSW and the mode switch MSW of the vehicle are not changed in the D mode D range. However, unlike the vehicle of the above-mentioned "control time chart (1)", the brake fluid pressure holding device RU does not include the relief valve RV. Here, the control time chart in the upper part of FIG. 10A is a diagram showing, in chronological order, increases and decreases in the driving force and the braking force of the vehicle. In the drawing, a thick line indicates the driving force, and a thin line indicates the braking force. The control time chart in the lower part of FIG. 10A shows that the solenoid valves SVA and SVB are ON (closed) /
It is the figure which showed OFF (open). FIG. 10B is a diagram showing a state of the brake hydraulic circuit BC at the time of stoppage, and the solenoid valves SV (SVA, SVB) are in an ON state (closed state).

First, the operation until the brake pedal BP is released is the same as in the case of the above-mentioned "control time chart (1)", and the description thereof will be omitted. The brake pedal B
Stepping release of P (Brake switch BSW [OFF])
Immediately before, the solenoid valves SVA and SVB are ON (closed),
The engine 1 is in an automatic stop state. In this state, when the driver releases the depression of the brake pedal BP, the braking force gradually decreases from the braking force at the time of releasing the depression of the brake pedal BP because the brake fluid pressure holding device RU does not include the relief valve RV. .

On the other hand, when the brake pedal BP is released, the brake switch BSW is turned off, an engine automatic start command (F_ENGON) is issued, and after a time lag due to signal communication and a delay in the mechanical system, the engine 1 automatically starts. I do. These points are the same as those in the case of the above-mentioned "control time chart (1)", and thus description thereof will be omitted.

The difference from the case of the above-mentioned "control time chart (1)" is the difference in the braking force at the time when the vehicle enters the strong creep state. "Control time chart (2)"
In the case of, since the relief valve RV is not provided, the braking force has a large value. However, in the strong creep state, the solenoid valves SVA and SVB are turned OFF (open state), and the braking force is instantaneously lost, so that unnecessary brake dragging does not occur. Brake pedal BP
It takes about 0.5 seconds from the release of the stepping on (after the brake switch BSW is turned off) to the strong creep state. After that, the driving force increases by further depressing the accelerator pedal, and the vehicle accelerates.

In the line indicating the braking force in the upper diagram of FIG. 10 (a), an imaginary line extending obliquely downward to the right from the “release of the brake pedal depression” indicates a case where the brake fluid pressure is not maintained. In this case, since the braking force is lost in a short time, it is not easy to start on a slope. Also, in the line indicating the braking force in the upper diagram of FIG. 10A, the imaginary line that gradually decreases obliquely downward to the right from the part where the solenoid valves SVA and SVB are OFF (open state) is
This shows a situation in which the braking force is reduced when the solenoid valves SVA and SVB are not turned off (open state). When the braking force is reduced as shown by the imaginary line, the brake is dragged, which is not preferable. V_BK in the lower diagram of FIG.
DLY indicates a delay time. After the delay time has elapsed, the solenoid valves SVA and SVB are turned off (open state) regardless of the situation as a fail-and-safe action. These points are the same as in the case of the aforementioned “control time chart (1)”.

As described above, the hill can be easily started without providing the relief valve RV in the brake fluid pressure holding device RU.

<< Control Time Chart when the Brake Fluid Pressure Holding Device is Normal (3) >> Lastly, with reference to FIG. 11, what kind of control is performed when the vehicle is running will be described. The position switch PSW and the mode switch MSW of the vehicle are not changed in the D mode D range. Further, the brake fluid pressure holding device RU is provided with a relief valve R.
V. Note that, unlike the vehicles of the above-mentioned "control time chart (1)" and "control time chart (2)", the vehicle of "control time chart (3)" does not perform control for automatically stopping the engine 1 when stopped. . Here, the control time chart in the upper part of FIG. 11 is a diagram showing, in chronological order, increases and decreases in the driving force and the braking force of the vehicle. In the drawing, a thick line indicates the driving force, and a thin line indicates the braking force. The lower control time chart of FIG. 11 shows ON (closed) / OFF of the solenoid valves SVA and SVB.
It is the figure which showed (open).

Until the vehicle stops, it is the same as the case of the above-mentioned "control time chart (1)" and the like, and the description thereof will be omitted. The electromagnetic valves SVA and SVB are turned on (closed state) by stopping the vehicle. On the other hand, the engagement force of the starting clutch is in a weak creep state even when the vehicle is stopped. In the weak creep state, there is almost no driving force, but fuel consumption is correspondingly small. Backing of the vehicle on a slope is prevented by the braking force. The conditions under which the driving force enters the weak creep state and the conditions under which the solenoid valves SVA and SVB are turned on (closed state) are as already described with reference to FIG.

Next, the driver releases the brake pedal BP in preparation for the restart. When the driver has depressed the brake pedal BP more than the relief pressure of the relief valve RV, as shown in FIG.
When the depression of P is released, the relief valve RV is operated, and the braking force is reduced to the relief pressure in a short time. By this relief valve RV, even when the driver depresses the brake pedal BP more than necessary, the vehicle can quickly start on a slope.

When the depression of the brake pedal BP is completely released (brake switch BSW [OFF]), a strong creep command (F_SCRP) is issued, the driving force increases, and a strong creep state is set (F_SCRPON). After the brake pedal BP is depressed and released, the solenoid valves SVA and SVB are in the ON state (closed state) until the strong creep state is reached.
, The brake fluid can move to the master cylinder MC side only through the small throttle D. Therefore, the braking force decreases only gradually, and the vehicle is prevented from moving backward. These points are the same as those described in the above “Control time chart (1)”.

Then, a strong creep state (F_SCRPO
In the case of N), a driving force capable of resisting a slope is generated, so that the braking force does not hinder the start of the vehicle, and in order to eliminate unnecessary dragging of the brake,
The solenoid valves SVA and SVB in the ON state (closed state) are turned off.
F (open state), the brake fluid pressure of the wheel cylinder WC is reduced at once, and the braking force is eliminated. After that, further depression of the accelerator pedal increases the driving force, and the vehicle accelerates. The conditions under which the driving force enters the strong creep state and the conditions under which the solenoid valves SVA and SVB are turned off (open state) are as already described with reference to FIG.

In the line indicating the braking force in the upper part of FIG. 11, a virtual line extending diagonally downward to the right from the “relief pressure” portion and a diagonal line extending from the portion where the solenoid valves SVA and SVB are OFF (open state) The description of the imaginary line and the like that gradually decreases downward is the same as the description in the above-mentioned “control time chart (1)”, and thus will be omitted.

<< Detection of Failure of Brake Fluid Pressure Holding Device >> Next, FIG.
This will be described with reference to FIGS. If the brake fluid pressure holding device RU fails, the brake force cannot be held when the brake pedal BP is released.
Therefore, the vehicle enters a strong creep state when the brake pedal BP is released when the vehicle is in a weak creep state by the driving force reduction device or when the engine 1 is in the automatic stop state by the motor stop device. Unable to maintain braking force until switching. As a result, when the vehicle starts on a slope, the vehicle moves backward when the brake pedal BP is released. Therefore, the brake fluid pressure holding device RU
It is necessary to stop the operation of the driving force reduction device and the motor stop device when the motor fails. In order to detect the failure, the vehicle includes a failure detection device DU.

[Failure Detection Device] The failure detection device DU in the CVT ECU 6 is a solenoid valve S of the brake fluid pressure holding device RU.
It drives VA / SVB (ON / OFF) and detects whether the brake fluid pressure holding device RU is operating normally. The detection of whether or not the brake fluid pressure holding device RU is operating normally is performed by the brake fluid pressure holding device RU.
It also includes whether the drive circuit of the solenoid valves SVA and SVB is normal. The drive circuit for the solenoid valves SVA and SVB is included in the failure detection device DU. When the failure detection device DU detects a failure of the brake fluid pressure holding device RU, CVTEC
U6 sets the strong creep state in the weak creep state and does not reduce the driving force by the driving force reduction device until the failure is eliminated. Further, the CVT ECU 6 determines that F
The information that the brake fluid pressure holding device RU is out of order is transmitted to the I / MG ECU 4 as information. And FI / MG
The ECU 4 controls the engine 1 if the engine 1 is in the automatic stop state.
Is automatically started, and the engine 1 is not automatically stopped by the motor stop device until the failure is eliminated.
It should be noted that the engine 1 is immediately brought into a strong creep state by the automatic start.

The failure detecting device DU will be described with reference to FIG. The failure detection device DU is a brake fluid pressure holding device RU.
The same circuit is provided for each of the two solenoid valves SVA and SVB. These two identical circuits are intelligent drivers IDa and IDa, which are driving elements having a self-diagnosis function.
Db or the like. Further, the failure detection device D
U is a central processing unit (hereinafter referred to as a CPU 6) of the CVT ECU 6.
a)). Since the failure detection device DU includes the same circuit having the same configuration and the same operation, only one of the circuits for the solenoid valve SVA will be described in detail.

First, the configuration of the circuit will be described with reference to FIG. The CPU 6a of the CVT ECU 6 is connected to the terminal Vin of the intelligent driver IDa. When the solenoid valve SVA is turned on (closed state), an H signal (5V) is transmitted and the solenoid valve SVA is turned off.
When it is set to (open state), an L signal (0 V) is transmitted.

Terminal V of intelligent driver IDa
The solenoid valve SVA of the brake fluid pressure holding device RU is connected to o. Then, according to the signal transmitted from the CPU 6a to the terminal Vin, the solenoid valve SVA is set to O from the terminal Vo.
When N, the current is supplied to the coil of the solenoid valve SVA to close the solenoid valve SVA, and when the solenoid valve SVA is turned off, no current is supplied. Therefore, when the brake fluid pressure holding device RU is normal, when the terminal Vin is at H (5 V), the terminal Vo is also at H (12 V), and the terminal Vin is at L (0 V).
In this case, the terminal Vo also becomes L (0 V).

Terminal V of intelligent driver IDa
b is connected to a 12V power supply from a battery (not shown). Further, a capacitor Ca is connected between the terminal Vb and the ground of the CVT ECU 6 to prevent noise. Further, a zener diode ZDa is connected between the terminal Vb and the terminal Vo in order to maintain an optimum voltage for turning on the solenoid valve SVA.

Terminal D of intelligent driver IDa
The CPU 6a is connected to the IAG and a resistor R
The power supply voltage 5V of the CVTECU 6 is connected via a. Then, according to H or L of the terminal Vo, the terminal DI
From the AG, H (5 V) or L (0 V) is supplied to the CPU 6a.
Send to The H signal or the L signal is a signal for detecting whether the intelligent driver IDa operates normally and whether the solenoid valve SVA connected to the intelligent driver IDa operates normally.

Terminal G of intelligent driver IDa
The ground of the CVT ECU 6 is connected to ND.

Next, the operation of the circuit and C accompanying the operation
The operation of the VT ECU 6 and the FI / MG ECU 4 will be described. In this description, description will be made separately depending on whether the brake hydraulic pressure holding device RU is operating normally or has failed.

A case where the brake fluid pressure holding device RU is normal will be described. When the CPU 6a of the CVT ECU 6 determines that the solenoid valve SVA of the brake fluid pressure holding device RU is ON, the CPU 6a determines the intelligent driver IDa.
H signal (5 V) is transmitted to the terminal Vin. Then, the intelligent driver IDa supplies a current to the coil of the solenoid valve SVA from the terminal Vo to close the solenoid valve SVA. At this time, the terminal Vo is at H (12 V).
As a result, the brake hydraulic pressure holding device RU operates, holds the brake hydraulic pressure in the wheel cylinder WC, and holds the braking force when the brake pedal BP is released. In this case, the terminal DIAG of the intelligent driver IDa
Outputs H (5 V) to the CPU 6 according to the output H of the terminal Vo.
Send to a. The CPU 6a confirms that the output H to the terminal Vin matches the input H from the terminal DIAG, and determines that the brake hydraulic pressure holding device RU is normal.

On the other hand, when the CPU 6a of the CVT ECU 6 determines that the solenoid valve SVA of the brake fluid pressure holding device RU is turned off, the CPU 6a
The L signal (0 V) is transmitted to the terminal Vin of Da. Then, the intelligent driver IDa does not supply a current from the terminal Vo to the solenoid valve SVA. Therefore, the solenoid valve SVA is in the open state. At this time, the terminal Vo is connected to L (0
V). As a result, the brake hydraulic pressure holding device RU does not operate, and does not hold the braking force when the brake pedal BP is released. In this case, the terminal DIAG of the intelligent driver IDa is set according to the output L of the terminal Vo.
L (0 V) is transmitted to the CPU 6a. The CPU 6a confirms that the output L to the terminal Vin matches the input L from the terminal DIAG, and determines that the brake fluid pressure holding device RU is normal.

The case where the brake hydraulic pressure holding unit RU is out of order will be described. A direct cause of the inability to hold the braking force in the brake fluid pressure holding device RU is when the solenoid valve SVA (or SVB) is open. That is, since the solenoid valve SVA (or SVB) and the failure detection circuit DU are disconnected, the solenoid valve SVA (or SVV) is disconnected.
B) cannot be switched to the holding position (the position where the solenoid valve is closed) by exciting B). Further, although not a direct cause, there is a case where the brake fluid pressure holding device RU cannot normally control the holding of the braking force. One is when the solenoid valve SVA (or SVB) is in a short circuit state.
That is, since the solenoid valve SVA (or SVB) is short-circuited, the solenoid valve SVA (or SVB) is always excited and cannot be switched to the open position (the position where the solenoid valve is open). The other is when the intelligent driver IDa (or IDb) is overheated. At this time, since the intelligent driver IDa (or IDb) may not be able to operate normally, the solenoid valve SVA (or SVB) may not be driven normally and the holding of the braking force may not be controlled normally.

The case where the solenoid valve SVA is open will be described. When the CPU 6a of the CVT ECU 6 determines that the solenoid valve SVA of the brake fluid pressure holding device RU is ON,
The CPU 6a transmits an H signal (5V) to the terminal Vin of the intelligent driver IDa. Then, the intelligent driver IDa supplies a current to the coil of the solenoid valve SVA from the terminal Vo to close the solenoid valve SVA. At this time, the terminal Vo is at H (12 V). However, since the solenoid valve SVA is disconnected from the terminal Vo, no current is supplied to the solenoid valve SVA. Therefore, the solenoid valve S
VA is not turned on because it is not excited. Therefore, the brake hydraulic pressure holding device RU does not operate, and the brake hydraulic pressure cannot be held in the wheel cylinder WC, so that the brake force is not held when the brake pedal BP is released. In this case, the terminal DIAG of the intelligent driver IDa transmits H (5 V) to the CPU 6a according to the output H of the terminal Vo. Since the output H to the terminal Vin and the input H from the terminal DIAG match, the CPU 6a cannot determine that the brake hydraulic pressure holding device RU has failed.

On the other hand, when the CPU 6a of the CVT ECU 6 determines that the solenoid valve SVA of the brake fluid pressure holding device RU is turned off, the CPU 6a
The L signal (0 V) is transmitted to the terminal Vin of Da. Then, the intelligent driver IDa does not supply a current from the terminal Vo to the solenoid valve SVA. However, the solenoid valve SV
Since terminal A is disconnected from terminal Vo, terminal Vo is at H (1
2V). At this time, the brake fluid pressure holding device R
U does not operate and does not hold the braking force when the brake pedal BP is released. In this case, the terminal DIAG of the intelligent driver IDa transmits H (5 V) to the CPU 6a according to the output H of the terminal Vo. CPU 6a
Is the output L from the terminal Vin and the input H from the terminal DIAG.
Are inconsistent with each other, and the brake fluid pressure holding device R
It is determined that U is out of order.

The case where the solenoid valve SVA is in a short-circuit state will be described. When the CPU 6a of the CVT ECU 6 determines that the solenoid valve SVA of the brake fluid pressure holding device RU is ON,
The CPU 6a transmits an H signal (5V) to the terminal Vin of the intelligent driver IDa. Then, the intelligent driver IDa supplies a current to the coil of the solenoid valve SVA from the terminal Vo to close the solenoid valve SVA. However, since the solenoid valve SVA is short-circuited, the solenoid valve SVA is in a continuous excitation state and is always in an ON state (closed state). Therefore, the terminal Vo becomes L (0 V). As a result, the brake fluid pressure holding device RU always operates, holds the brake fluid pressure in the wheel cylinder WC, and keeps the braking force when the brake pedal BP is released. In this case, the terminal DIAG of the intelligent driver IDa transmits L (0 V) to the CPU 6a according to the output L of the terminal Vo. The CPU 6a outputs the output H to the terminal Vin and the terminal DI
It is confirmed that the input L from the AG does not match, and it is determined that the brake fluid pressure holding device RU has failed.

On the other hand, when the CPU 6a of the CVT ECU 6 determines that the solenoid valve SVA of the brake fluid pressure holding device RU is turned off, the CPU 6a
The L signal (0 V) is transmitted to the terminal Vin of Da. Then, the intelligent driver IDa does not supply a current from the terminal Vo to the solenoid valve SVA. However, the solenoid valve SV
A is in a continuously excited state because it is short-circuited.
This is the N state (closed state). Therefore, the terminal Vo is at L
(0 V), and as a result, the brake fluid pressure holding device RU
Always operates, the brake fluid pressure is held in the wheel cylinder WC, and the brake force is always held when the brake pedal BP is released. In this case, the terminal DIAG of the intelligent driver IDa transmits L (0 V) to the CPU 6a according to the output L of the terminal Vo. CPU 6a
Is the output L from the terminal Vin and the input L from the terminal DIAG.
Are matched, the brake fluid pressure holding device R
It cannot be determined that U is out of order.

A case where the intelligent driver IDa is overheated will be described. CPU 6 of CVT ECU 6
When determining that a turns on the electromagnetic valve SVA of the brake fluid pressure holding device RU, the CPU 6a transmits an H signal (5V) to the terminal Vin of the intelligent driver IDa.
However, since the intelligent driver IDa is overheated, it does not operate normally and cannot supply current from the terminal Vo to the solenoid valve SVA. At this time, the terminal Vo becomes L (0 V). As a result, the brake fluid pressure holding device RU does not operate, and does not hold the braking force when the brake pedal BP is released. In this case, the intelligent driver ID
The terminal DIAG of a is connected to L in accordance with the output L of the terminal Vo.
(0 V) is transmitted to the CPU 6a. The CPU 6a confirms that the output H to the terminal Vin and the input L from the terminal DIAG do not match, and determines that the brake hydraulic pressure holding unit RU has failed. In this case, to be precise, it is a failure of the drive circuit of the solenoid valve SVA of the brake fluid pressure holding device RU.

On the other hand, when the CPU 6a of the CVT ECU 6 determines that the electromagnetic valve SVA of the brake fluid pressure holding device RU is turned off, the CPU 6a
The L signal (0 V) is transmitted to the terminal Vin of Da. However, since the intelligent driver IDa is overheated, it does not operate normally and does not supply current from the terminal Vo to the solenoid valve SVA. At this time, the terminal Vo becomes L (0 V).
As a result, the brake hydraulic pressure holding device RU does not operate, and does not hold the braking force when the brake pedal BP is released. In this case, the terminal DIAG of the intelligent driver IDa transmits L (0 V) to the CPU 6a according to the output L of the terminal Vo. Since the output L to the terminal Vin and the input L from the terminal DIAG match, the CPU 6a cannot determine that the brake hydraulic pressure holding device RU has failed.

When the CPU 6a of the CVT ECU 6 detects the failure of the brake fluid pressure holding device RU, the CVT ECU 6 prohibits the operation of the driving force reduction device and does not enter the weak creep state. That is, the CVT ECU 6 maintains the strong creep state because the condition for setting the weak creep state described above (see the condition of FIG. 7A) is not satisfied due to the failure of the brake fluid pressure holding device RU. In the case where the driving force reduction device is in a weak creep state when the failure is detected, C
The VTECU 6 transmits V_SCHP to the CVT 3 and
The engaging force of the starting clutch of the VT3 is increased to bring the VT3 into a strong creep state.

The CVT ECU 6 sets F_CVTOK
F_CVTOK is switched to 0 because the brake fluid pressure holding device RU in the above condition does not satisfy the normal condition. Then, the FI / M to which the F_CVTOK that has become 0 is transmitted
The GECU 4 prohibits the operation of the motor stop device and does not automatically stop the engine 1. That is, FI / MGE
The CU 4 does not automatically stop the engine 1 because the above-described engine automatic stop condition (see FIG. 7B) is not satisfied because the brake fluid pressure holding unit RU is out of order. Further, when the engine 1 is in the automatic stop state at the time when the failure of the brake fluid pressure holding device RU is detected, F_CVTOK switches from 1 to 0, and the C_VT ECU 6 switches from FI / MG to FI / MG.
It is transmitted to the ECU 4. While the engine 1 is stopped, F
_CVTOK in CVT3 in weak creep state, CV
The condition that the ratio of T3 is low, the oil temperature of CVT3 is equal to or higher than a predetermined value, and the brake fluid temperature is equal to or higher than a predetermined value is maintained. Therefore, while the engine 1 is stopped, F_CVTOK changes from 1 to 0 when a failure of the brake fluid pressure holding device RU is detected.
Switch to. Then, FI / MG ECU 4 sets the MOT
The engine 1 start mode is transmitted to the ECU 5 by I_MG. Further, the MOTECU 5 supplies the motor 1 with the engine 1
And the engine 1 is automatically started by the motor 2. Immediately after the automatic start of the engine 1, a strong creep state is set.

As described above, when the brake fluid pressure holding unit RU fails, the vehicle maintains the strong creep state, or immediately switches to the strong creep state in the case of the weak creep state or the automatic engine 1 stop state. As a result, when the vehicle starts on a slope, the vehicle does not retreat even if the brake pedal BP is released.

FIG. 12B shows the terminals Vin, Vo, and the terminals of the intelligent driver IDa (or IDb) described above.
The truth values of DIAG are tabulated, and the truth is shown in FIG. 12 (c). As described above, the CPU 6a
Can detect an abnormality when the truth (H or L) of the terminal Vin and the terminal DIAG do not match. Therefore, when the solenoid valve SVA (or SVB) is open, the terminal Vin is L, when the solenoid valve SVA (or SVB) is short, the terminal Vin is H, and when the intelligent driver IDa (or IDb) is overheated, the terminal V is connected.
An abnormality can be detected when in is H.

Next, the control of the braking force and the driving force when the brake fluid pressure holding device RU of the vehicle is out of order will be described in chronological order. This vehicle is provided with a driving force reduction device and a motor stopping device. Here, there are three patterns of a case where only the driving force reduction device is provided, a case where the driving force reduction device and the motor stopping device are provided, and a case where only the motor stopping device is provided. Will be described.

<< Control Time Chart when Detecting Failure of Brake Fluid Pressure Holding Device (1) >> Referring to FIG. 13, the braking force when the driving force reduction device is provided and brake fluid pressure holding device RU fails is determined. The control of the driving force will be described in chronological order. In this case, both the driving force reduction device and the prime mover stopping device are provided, but this also corresponds to the case where the engine 1 does not automatically stop because the engine automatic stop condition is not satisfied. The position switch PSW and the mode switch MSW of the vehicle do not change the D range D mode. In addition, the control time chart in the upper part of FIG. 13 is a diagram showing, in chronological order, the increase and decrease of the driving force and the braking force of the vehicle, in which a thick line indicates the driving force, a thin line indicates the braking force, The broken line indicates the driving force when the driving force reduction device operates. The control time chart in the lower part of FIG. 13 shows ON (closed) / OFF of the solenoid valves SVA and SVB.
It is the figure which showed (open).

Until the brake pedal BP is depressed and the brake switch BSW is turned on, the driving force has a driving force according to the amount of depression of an accelerator pedal (not shown), and there is no braking force. Then, when the accelerator pedal is released and the brake pedal BP is depressed to turn on the brake switch BSW, the driving force decreases, the braking force increases, and the vehicle speed decreases. Further, the driving force is reduced, a strong creep state is caused (normal idling state), and the braking force is maximized.

Normally, at the time point S5 when the brake switch BSW is turned on and the vehicle speed reaches 5 km / h, the driving force reduction device issues a weak creep command and reduces the driving force until the vehicle enters a weak creep state (FIG. 13). Broken line). However, since the failure detection device DU has detected the failure of the brake fluid pressure holding device RU, the operation of the driving force reduction device is prohibited and the weak creep command is not issued. Therefore, a strong creep state is maintained.

Further, at time S0 when the vehicle speed decreases, the vehicle is weakly creeped and the vehicle speed becomes 0 km / h, the solenoid valves SVA and SVB of the brake fluid pressure holding unit RU are normally turned on (closed).
I do. However, since the brake fluid pressure holding device RU is out of order, the solenoid valves SVA and SVB are not turned on and are kept open.

As a result, when the depression of the brake pedal BP is started, the brake fluid pressure holding device RU does not operate. Therefore, the brake fluid pressure of the wheel cylinder WC decreases in accordance with the decreasing speed of the depression of the brake pedal BP. ,
The braking force also decreases. That is, the wheel cylinder W
The brake fluid pressure of C is not maintained, and the braking force is not maintained. However, since the driving force is maintained in a strong creep state, the vehicle does not retreat even on a slope.

According to the vehicle having only the driving force reduction device, when the brake fluid pressure holding device RU fails, the failure detection device DU detects the failure and inhibits the operation of the driving force reduction device. Therefore, even if the brake pedal BP is depressed and the vehicle speed becomes 5 km / h or less, the strong creep state is maintained. Further, even if the brake fluid pressure holding device RU breaks down after the weak creep state, the state is switched to the strong creep state at that time. Therefore, when the brake pedal BP is released, the vehicle is in a strong creep state. As a result, even if the brake hydraulic pressure holding device RU breaks down, the vehicle does not move backward because the vehicle is in a strong creep state when the vehicle starts on a slope.

<< Control Time Chart when Detecting Failure of Brake Fluid Pressure Holding Device (2) >> Referring to FIG. 14, when a driving force reduction device and a motor stop device are provided and brake fluid pressure holding device RU has a failure. The control of the braking force and the driving force will be described in chronological order. The position switch PSW and the mode switch MSW of the vehicle do not change the D range D mode. The control time chart in the upper part of FIG. 14 is a diagram showing, in chronological order, the increase and decrease of the driving force and the braking force of the vehicle, where a thick line indicates the driving force, a thin line indicates the braking force, The broken lines indicate the driving force when the driving force reduction device and the motor stop device are activated. The control time chart in the lower part of FIG. 14 is a diagram showing ON (closed) / OFF (open) of the solenoid valves SVA and SVB.

Until the brake pedal BP is depressed and the brake switch BSW is turned on, the driving force has a driving force according to the depression amount of an accelerator pedal (not shown), and there is no braking force. Then, when the accelerator pedal is released and the brake pedal BP is depressed to turn on the brake switch BSW, the driving force decreases, the braking force increases, and the vehicle speed decreases. Further, the driving force is reduced, a strong creep state is caused (normal idling state), and the braking force is maximized.

Normally, at the time point S5 when the brake switch BSW is turned on and the vehicle speed becomes 5 km / h, the driving force reducing device issues a weak creep command and reduces the driving force until the vehicle enters a weak creep state (FIG. 14). Broken line). However, since the failure detection device DU has detected the failure of the brake fluid pressure holding device RU, the operation of the driving force reduction device is prohibited and the weak creep command is not issued. Therefore, a strong creep state is maintained.

Further, at the time S0 when the vehicle speed decreases, the vehicle is weakly creeped and the vehicle speed becomes 0 km / h, the solenoid valves SVA and SVB of the brake fluid pressure holding device RU are normally turned on (closed).
I do. However, since the brake fluid pressure holding device RU is out of order, the solenoid valves SVA and SVB are not turned on and are kept open. Also, at the time S0 when the vehicle speed becomes 0 km / h,
Usually, the motor stop device confirms that the engine automatic stop condition is satisfied, and automatically stops the engine 1. Therefore, there is no driving force as shown by the broken line in FIG. However, since the failure of the brake fluid pressure holding device RU is detected by the failure detection device DU,
The operation is prohibited and the engine 1 is not automatically stopped. Therefore, a strong creep state is maintained.

As a result, when the depression of the brake pedal BP is started, the brake fluid pressure holding device RU does not operate. Therefore, the brake fluid pressure of the wheel cylinder WC decreases according to the decreasing speed of the depression of the brake pedal BP. ,
The braking force also decreases. That is, the wheel cylinder W
The brake fluid pressure of C is not maintained, and the braking force is not maintained. However, since the driving force is maintained in a strong creep state, the vehicle does not retreat even on a slope.

According to the vehicle having the driving force reducing device and the motor stopping device, when the brake hydraulic pressure holding device RU fails, the failure is detected by the failure detecting device DU, and the driving force reducing device and the motor stopping device are determined. Operation is prohibited. Therefore, even if the brake pedal BP is depressed and the vehicle speed becomes 5 km / h or less, the strong creep state is maintained. Further, even if the vehicle speed becomes 0 km / h, the strong creep state is maintained without automatically stopping the engine 1. Further, even if the brake fluid pressure holding device RU fails after the engine 1 automatically stops, at that time, the engine 1 is automatically started and switched to the strong creep state. Therefore, when the brake pedal BP is released, the vehicle is in a strong creep state. As a result, even if the brake hydraulic pressure holding device RU breaks down, the vehicle does not move backward because the vehicle is in a strong creep state when the vehicle starts on a slope.

<< Control Time Chart when Detecting Failure of Brake Fluid Pressure Holding Device (3) >> Referring to FIG. 15, the braking force and drive when a motor stop device is provided and brake fluid pressure holding device RU fails are provided. The control of the force will be described in chronological order. The position switch PSW and the mode switch MSW of the vehicle do not change the D range D mode. In addition, the control time chart in the upper part of FIG. 15 is a diagram showing the increase and decrease of the driving force and the braking force of the vehicle in chronological order, in which a thick line indicates the driving force, a thin line indicates the braking force, The broken line indicates the driving force at the time of operating the motor stop device. The control time chart in the lower part of FIG. 15 shows that the solenoid valves SVA and SVB are ON (closed) / OFF (open).
FIG.

Until the brake pedal BP is depressed and the brake switch BSW is turned on, the driving force has a driving force in accordance with the depression amount of an accelerator pedal (not shown), and there is no braking force. Then, when the accelerator pedal is released and the brake pedal BP is depressed to turn on the brake switch BSW, the driving force decreases, the braking force increases, and the vehicle speed decreases. Further, the driving force is reduced, a strong creep state is caused (normal idling state), and the braking force is maximized.

Further, at the time S0 when the vehicle speed decreases to a weak creep state and the vehicle speed becomes 0 km / h, the solenoid valves SVA and SVB of the brake fluid pressure holding device RU are normally turned on (closed).
I do. However, since the brake fluid pressure holding device RU is out of order, the solenoid valves SVA and SVB are not turned on and are kept open. Also, at the time S0 when the vehicle speed becomes 0 km / h,
Usually, the motor stop device confirms that the engine automatic stop condition is satisfied, and automatically stops the engine 1. Therefore, there is no driving force at all, as indicated by the broken line in FIG. However, since the failure of the brake fluid pressure holding device RU is detected by the failure detection device DU,
The operation is prohibited and the engine 1 is not automatically stopped. Therefore, a strong creep state is maintained.

As a result, when the depression of the brake pedal BP is started, the brake fluid pressure holding device RU does not operate. Therefore, the brake fluid pressure of the wheel cylinder WC decreases in accordance with the speed at which the brake pedal BP is depressed. ,
The braking force also decreases. That is, the wheel cylinder W
The brake fluid pressure of C is not maintained, and the braking force is not maintained. However, since the driving force is maintained in a strong creep state, the vehicle does not retreat even on a slope.

According to the vehicle having only the motor stop device, when the brake fluid pressure holding device RU fails, the failure detection device DU detects the failure and inhibits the operation of the motor stop device. Therefore, even when the brake pedal BP is depressed and the vehicle speed becomes 0 km / h,
The strong creep state is maintained without the engine 1 being automatically stopped. Further, even if the brake fluid pressure holding device RU fails after the engine 1 automatically stops, at that time, the engine 1 is automatically started and switched to the strong creep state. Therefore, when the brake pedal BP is released, the vehicle is in a strong creep state. As a result, even if the brake hydraulic pressure holding device RU breaks down, the vehicle does not move backward because the vehicle is in a strong creep state when the vehicle starts on a slope.

As described above, the present invention is not limited to the above-described embodiment, but can be embodied in various forms. For example, the failure detection device is configured to also serve as a drive circuit for the electromagnetic valve of the brake fluid pressure holding device, but may be configured separately. In addition, an intelligent driver, which is a driving element having a self-diagnosis function, is used to configure the failure detection device. However, the present invention is not limited to this configuration, and may be configured by various electronic circuits. Further, the failure detecting device may be configured to monitor the brake fluid pressure of the brake fluid pressure retaining device and detect a failure of the brake fluid pressure retaining device based on a change in the value of the brake fluid pressure. Further, the configuration of the failure detection device and the detection method varies depending on the configuration of the brake fluid pressure holding device, and is not particularly limited. For example, in a configuration in which a traction control system is used as a brake fluid pressure holding device, a failure detection device may be incorporated in a device that monitors the traction control system. Further, the motor-equipped vehicle according to the present invention can employ various structures in the motor, the driving force reducing device, the motor stopping device, or the brake fluid pressure holding device.

[0178]

As described above, according to the vehicle with the motor of the first aspect, the failure of the brake fluid pressure holding device is detected, and the operation of the driving force reduction device is prohibited when the failure is detected.
Therefore, the driving force is maintained at a large state irrespective of the depressed state of the brake pedal and the like, and it is possible to prevent the vehicle with the motor from moving backward when the vehicle starts on a slope. Further, when a failure of the brake fluid pressure holding device is detected after the driving force is reduced by the driving force reducing device, the driving force can be switched to a large state before the brake pedal is released. Therefore, when the brake pedal is released, there is no time lag until the driving force increases,
It is possible to prevent the motor vehicle from moving backward when the vehicle starts on a slope.

According to the vehicle with the motor according to the second aspect of the present invention, the failure of the brake fluid pressure holding device is detected, and when the failure is detected, the operation of the driving force reduction device and the motor stop device is prohibited. Therefore, irrespective of the depressed state of the brake pedal or the like, the driving force is maintained at a large state, and it is possible to prevent the vehicle with the motor from retreating when starting on a slope. Also, if a failure of the brake fluid pressure holding device is detected after the driving force is reduced by the driving force reduction device and the motor is automatically stopped by the motor stopping device, the motor is restarted before the brake pedal is released. However, the driving force can be switched to a large state. Therefore, when the depression of the brake pedal is released, no time lag occurs until the driving force increases, and it is possible to prevent the vehicle with the motor from moving backward when the vehicle starts on a slope.

According to the vehicle with the motor according to the third aspect of the present invention, the failure of the brake fluid pressure holding device is detected, and when the failure is detected, the operation of the motor stopping device is prohibited. Therefore, the driving force is maintained at a large state irrespective of the depressed state of the brake pedal and the like, and it is possible to prevent the vehicle with the motor from moving backward when the vehicle starts on a slope. Also, if a failure of the brake fluid pressure holding device is detected after the prime mover is automatically stopped by the prime mover stopping device, the prime mover is restarted and the driving force is switched to a large state before the brake pedal is released. Can be. Therefore, when the depression of the brake pedal is released, no time lag occurs until the driving force increases, and it is possible to prevent the vehicle with the motor from moving backward when the vehicle starts on a slope.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of a motor vehicle according to the present invention.

FIG. 2 is a configuration diagram of a variation in which a brake hydraulic pressure holding device for a motor vehicle according to the present invention is provided in a brake hydraulic circuit of a hydraulic brake device.

FIG. 3 is a configuration diagram of a variation in which a brake hydraulic pressure holding device for a motor vehicle according to the present invention is provided outside a brake hydraulic circuit of a hydraulic brake device.

FIG. 4 is a cross-sectional view showing a specific structure of a brake fluid pressure holding device for a motor vehicle according to the present invention.

5 is an enlarged sectional view of (a) an essential part of a relief valve and a throttle portion of the brake fluid pressure holding device of FIG. 4, (b) an operation diagram when a throttle is formed by cutting, and (c) pressing a throttle. FIG. 3 is an operation diagram when forming by (1), (c-1) is an operation diagram showing groove processing, and (c-2) is an operation diagram showing coining.

FIG. 6 is a configuration diagram of a variation in which a proportional solenoid valve is used for a brake fluid pressure holding device of a motor vehicle according to the present invention.

7 (a) is a logic for turning on the solenoid valve of the brake fluid pressure holding device of the motor vehicle according to the present invention, (b)
This is the condition for automatically stopping the engine.

FIG. 8 is a diagram illustrating logic for turning off the solenoid valve of the brake fluid pressure holding device in the motor vehicle according to the present invention;
(B) Conditions for automatic engine start.

FIG. 9 is a control time chart of (a) the driving force, the braking force, and the solenoid valve ON / OFF when the brake fluid pressure holding device is normal in the motor vehicle according to the present invention, and (b) the brake fluid pressure when the vehicle is stopped. It is a block diagram of a circuit.

FIG. 10 (a) when the brake fluid pressure holding device without the relief valve in the motor vehicle according to the present invention is normal.
It is a control time chart of a driving force, a braking force, and a solenoid valve ON / OFF, and (b) is a configuration diagram of a brake hydraulic circuit when the vehicle stops.

FIG. 11 is a control time chart of the driving force and the braking force and the solenoid valve ON / OFF when the engine is not stopped and the brake fluid pressure holding device is normal in the motor vehicle according to the present invention.

12A is a circuit diagram, FIG. 12B is a diagram illustrating a truth table, and FIG. 12C is a diagram illustrating the truth of FIGS. 12C and 12B of the failure detection device for a motor vehicle according to the present invention.

FIG. 13 is a control time chart of the driving force, the braking force, and the solenoid valve ON / OFF when the driving force reducing device is provided in the motor vehicle according to the present invention and the brake fluid pressure holding device fails.

FIG. 14 is a control time chart of the driving force, the braking force, and the solenoid valve ON / OFF when the driving force reducing device and the motor stopping device are provided in the motor vehicle according to the present invention and the brake fluid pressure holding device fails. is there.

FIG. 15 is a control time chart of a driving force and a braking force and a solenoid valve ON / OFF when a motor stop device is provided in the vehicle with a motor according to the present invention and the brake fluid pressure holding device fails.

[Explanation of symbols]

1: Engine (motor) 3: Belt-type continuously variable transmission (CVT) (driving force reducing device) 4: Fuel injection / management electronic control unit (FI / MG ECU) (motor stopping device) 5. ..Electronic control unit for motor (MOTECU) 6 ... Electronic control unit for CVT (CVT ECU) (driving force reduction device) 8 ... Driving wheel BP ... Brake pedal DU ... Fault detection device RU ... Brake Hydraulic pressure holding device WC ・ ・ ・ Wheel cylinder

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI F02D 29/02 341 F02D 29/02 341 (72) Inventor Takahiro Eguchi 1-4-1 Chuo, Wako-shi, Saitama Honda Motor Co., Ltd. Inside the research institute (72) Inventor Tetsuro Yamaguchi 1-4-1 Chuo, Wako-shi, Saitama Pref. In Honda R & D Co., Ltd. (72) Inventor Hirotoshi Inoue 1-4-1 Chuo in Wako-shi, Saitama pref. (56) References JP-A-9-210093 (JP, A) JP-A-7-144625 (JP, A) JP-A-8-119083 (JP, A) JP-A-61-102363 (JP, A) Open Sho 64-21026 (JP, A) Open Sho 61-17368 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F02D 29/00-29/06 B60K 41/00- 41/28 B60T 7/12-7/22 B60T 8/00 B60T 8/32-8/96

Claims (3)

(57) [Claims] When a driving range is selected in a transmission even when an accelerator pedal is depressed and released, a vehicle with a motor that transmits driving force from a motor to driving wheels is provided. A driving force reducing device that switches the magnitude of the driving force according to the depression of a brake pedal, and reduces the driving force when the brake pedal is depressed as compared with when the brake pedal is depressed; and after the brake pedal is depressed. And a brake fluid pressure holding device capable of continuously applying brake fluid pressure to the wheel cylinders. A motorized vehicle comprising: a failure detection device that detects a failure of the brake fluid pressure retention device; With a motor, wherein the operation of the driving force reduction device is prohibited when a failure of the hydraulic pressure holding device is detected. Both. 2. A vehicle with a motor that transmits a driving force from a motor to a driving wheel when a travel range is selected in the transmission even when the accelerator pedal is depressed and released, when the vehicle speed is lower than a predetermined low vehicle speed, A driving force reduction device that switches the magnitude of the driving force in accordance with the depression of a brake pedal, and reduces the driving force when the brake pedal is depressed as compared to when the brake pedal is released; A motor-equipped vehicle comprising: a motor stopping device capable of stopping the motor; and a brake fluid pressure holding device capable of continuously applying a brake fluid pressure to a wheel cylinder even after the brake pedal is released. A failure detection device for detecting a failure of the brake fluid pressure holding device is detected by the failure detection device. A motor-equipped vehicle, wherein the operation of the driving force reduction device and the motor stop device is prohibited when the vehicle stops. 3. A motor-operated vehicle that transmits a driving force from a motor to a driving wheel when a travel range is selected in the transmission even when the accelerator pedal is depressed and released, wherein the motor-powered vehicle stops when the motor-equipped vehicle stops. A motor-equipped vehicle comprising: a motor stop device capable of stopping a motor; and a brake fluid pressure holding device capable of continuously applying brake fluid pressure to a wheel cylinder even after a brake pedal is depressed and released. A motor-equipped vehicle, comprising: a failure detection device that detects a failure of the brake fluid pressure holding device when the failure detection device detects a failure of the brake fluid pressure holding device.