JP2001047988A - Braking force holding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To conduct a stable starting operation by properly releasing held braking force. SOLUTION: This holding device holds braking force to apply uninterruptedly to a vehicle the braking force in response to pedaling force of a brake pedal BP before releasing of the pedaling after the pedaling of the brake pedal BP is released at the time of vehicle stop, and releases the holding of the braking force when an starting operation. In this case, a time from a start of reduction of the braking force upto disappearance of the braking force is controlled to be constant irrespective of levels of the held braking force, when the holding of the braking force is released.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a braking force holding device capable of holding a braking force even after a brake pedal is depressed and released.

[0002]

2. Description of the Related Art Conventionally, when a vehicle is stopped, a hydraulic pressure passage between a master cylinder and a wheel cylinder is shut off by a solenoid valve, and the brake fluid pressure is maintained until a start operation is performed even after a brake pedal is released. The brake force holding device that makes it easy to start the vehicle smoothly without reversing on the uphill road,
For example, JP-A-60-12360 (vehicle braking device) and JP-A-63-43854 (control device of brake fluid pressure holding device) are known. The former vehicle braking device is provided with an electromagnetic check valve in the hydraulic passage between the master cylinder and the wheel cylinder, and by operating this valve, the flow of the brake fluid is prevented so that the brake force is maintained even after the brake pedal is released. Hold. The electronic control unit determines the operation signal and release signal of the solenoid valve based on detection signals from various detection devices such as a vehicle speed sensor, an accelerator pedal sensor, a clutch sensor, an engine rotation sensor, and a brake pedal switch. The control device of the latter brake fluid pressure holding device includes a tilt detection means, a reverse gear switch, a clutch switch, a brake switch, a valve capable of holding the brake fluid pressure even after the brake pedal is released, and an instruction of the fluid pressure holding operation and a fluid pressure holding valve. And a control unit for giving an instruction to release the pressure based on a signal from the inclination detecting means or the like.

[0003] Generally, the larger the inclination angle (ie, the road gradient) of the vehicle at the time of stopping and the larger the loaded weight, the larger the amount of braking required to hold the vehicle in the stopped state. Depress the pedal strongly. Therefore, if the braking force (brake fluid pressure in the wheel cylinder) corresponding to the depression of the brake pedal by the driver is maintained as it is, an appropriate braking force corresponding to the inclination angle and the loaded weight of the vehicle is normally maintained.

[0004]

However, even if the braking force to be held is maintained at an appropriate braking force corresponding to the inclination angle of the vehicle and the weight of the vehicle at that time, the braking force at the time of starting operation is increased. If the release is not properly performed, the driver cannot perform a stable start operation. Therefore, an object of the present invention is to provide a brake force holding device that enables a stable starting operation by appropriately releasing the holding brake force.

[0005]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems. According to the present invention, after the brake pedal is released when the vehicle is stopped, the brake force corresponding to the depression force of the brake pedal before the release is continuously released. A braking force holding device that holds a braking force so as to act on a vehicle, and releases the holding of the braking force when a start operation is performed.When releasing the holding of the braking force, the device starts reducing the braking force. It is characterized in that the time from when the brake force is no longer applied until when the brake force is stopped is controlled irrespective of the magnitude of the brake force.

[0006] According to this, the time from when the starting operation is performed and the reduction of the braking force is started until the braking force is stopped is made constant regardless of the magnitude of the braking force when the vehicle is stopped. it can. The held braking force has a correlation with the vehicle inclination angle (road gradient) and the loaded weight, and the steeper the steeper the greater the holding brake force.

In the present embodiment, the term "braking force according to the depression of the brake pedal" refers to maintaining the brake fluid pressure sent to the wheel cylinder as it is in the present embodiment. It is only necessary that the braking force proportional to the pedaling force be applied to the vehicle continuously, and instead of maintaining the brake fluid pressure sent to the wheel cylinder as it is, the brake pressure is reduced or the brake pedal is released. In a brake device provided with a pump capable of generating brake fluid pressure regardless of depression, the pressure may be increased and held.

[0008] The term "start operation" in the claims includes the following three cases. Depressing accelerator pedal by driver (vehicle equipped with automatic transmission) Depressing accelerator pedal and connecting clutch by driver (vehicle equipped with manual transmission) Driving to the extent that it automatically resists slopes by releasing the brake pedal In a vehicle in which the driving force transmission capacity of the starting clutch is increased so as to increase the force, the depression of the brake pedal is released and the driving force is increased thereafter (the present embodiment).

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a braking force holding device according to the present invention will be described below with reference to the drawings. 1 is a system configuration diagram of a vehicle equipped with a braking force holding device, FIG. 2 is a configuration diagram of the braking force holding device, FIG. 3 is a control logic for holding the braking force, and FIG. 4A is a control logic for permitting the operation of the braking force holding device, FIG. 4A is a control logic for setting the driving force control device to a weak creep state, FIG. 5 is a control logic for making a medium creep state, FIG. 5 is a control logic for automatically stopping an engine of a motor stopping device, FIG. 6 is a control logic for releasing a holding of a braking force, and FIG.
(B) is a control logic for judging the rise of creep, FIG. 7 is a drive force control device (a) is a control logic for setting a strong creep state (vehicle retreat detection version), (b)
Is a control logic (vehicle movement detection version) for setting a strong creep state, and FIG. 8 is an example of a vehicle backward detection method.
(A) is a configuration diagram of vehicle backward detection, (b) is a pulse phase of directional rotation in (a), (c) is a pulse phase of directional rotation in (a), and FIG. 9 is (a) of a motor stopping device. ) Is a control logic for automatically starting the engine (vehicle reversal detection version), (b) is a control logic for automatically starting the engine (vehicle movement detection version), FIG. 10 is a control flowchart of the braking force holding device, and FIG. 11 is a braking force. FIG. 12 is a control time chart in the case where the engine of the vehicle equipped with the holding device is not stopped, and FIG. 12 is the control time chart in the case where the engine of the vehicle equipped with the braking force holding device is stopped.

The brake force holding device of the present embodiment is mounted on a vehicle equipped with a prime mover, and can continuously hold the braking force even after the brake pedal is depressed and released when the vehicle starts moving. When releasing the holding of the braking force, the time from the start of the reduction of the braking force to the end of the braking force (hereinafter referred to as “braking force release time”)
) Regardless of the magnitude of the braking force that was held. This vehicle has a driving force control device that switches the driving force of creep between a large state and a small state in accordance with the depressed state of the brake pedal when the prime mover is in an idling state and at a predetermined vehicle speed or less. Creep is defined as D range or R in vehicles with automatic transmission.
When a driving range such as a range is selected, the vehicle slowly moves in a creeping manner without depressing the accelerator pedal (the engine is idling).

<< System Configuration of Vehicle, etc. >> First, the system configuration of the vehicle according to the present embodiment will be described with reference to FIG. Details of the braking force holding device will be described after the system configuration of the vehicle. The vehicle described in the present embodiment is a hybrid vehicle including an engine 1 that is an internal combustion engine powered by gasoline or the like as a prime mover and a motor 2 powered by electricity, and a belt-type continuously variable transmission as a transmission. 3 (hereinafter, referred to as CVT3). In the vehicle of the present invention, the prime mover is not particularly limited, such as only the engine or only the motor as the prime mover. Further, the transmission is not particularly limited, such as an automatic transmission or a manual transmission including a torque converter as the transmission.

[Engine (Motor) / CVT (Transmission)
[Motor (Motor)] The engine 1 is controlled by a fuel injection electronic control unit (hereinafter referred to as FIECU). The FIECU is configured integrally with a management electronic control unit (hereinafter, referred to as MG ECU),
Electronic control unit for fuel injection / management (hereinafter referred to as F
I / MG ECU 4). Also,
The motor 2 is a motor electronic control unit (hereinafter referred to as “MOTE”).
CU). Furthermore, CVT3
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 provided with disc 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 braking force 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.

The engine 1 is an internal combustion engine that utilizes heat energy, and drives driving wheels 8 via a CVT 3 and a driving 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 start mode for starting.

The CVT 3 changes the speed ratio steplessly 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. In addition, the vehicle equipped with the CVT 3 is capable of creep running when idling,
A driving force control unit DCU for reducing the driving force of creep
Is provided.

[Driving force control unit] Driving force control unit DCU
Is provided in the CVT 3 and variably controls the driving force transmission capacity of the starting clutch to switch the magnitude of the creep driving force. Further, when detecting the vehicle movement (or the vehicle retreat), the driving force control device DCU increases the driving force. Note that the driving force control unit DCU has a CVTEC described later.
U6 is also included in the configuration. Driving force control unit DCU
The CVT ECU 6 determines the conditions for the weak creep state, the conditions for the medium creep state, the conditions for the strong creep state, and the conditions for the strong creep state during running, which will be described later, and changes the driving force transmission capacity of the starting clutch. Then, the driving force is switched to a preset driving force in each creep state. further,
When detecting whether the vehicle has retreated or the vehicle has moved when starting uphill, the driving force control device DCU increases the driving force transmission capacity of the starting clutch and switches to the strong creep state. The driving force control unit DCU determines each condition for switching the driving force of creep by the CVT ECU 6, and determines the CVT
The ECU 6 transmits a hydraulic pressure command value to the CVT 3 to the linear solenoid valve that controls the hydraulic pressure applied to the starting clutch. Then, the driving force control unit DCU switches the engagement force of the starting clutch based on the hydraulic pressure command value in the CVT 3.
As a result, the driving force transmission capacity also changes, and the driving force for creep switches. The vehicle is controlled by the driving force control device DC.
By reducing the driving force by U, fuel efficiency is improved. The improvement in fuel efficiency is realized by reducing the load on the engine 1 and the load on the hydraulic pump in the starting clutch. Here, the driving force transmission capacity means the maximum driving force (driving torque) that can be transmitted by the starting clutch. That is, when the driving force generated by the engine 1 exceeds the driving force transmission capacity, the starting clutch cannot transmit the driving force exceeding the driving force transmission capacity to the driving wheels 8. Incidentally, when the failure detection device DU detects a failure in the brake force holding device RU, the switching to the weak creep state by the driving force control device DCU is prohibited.

The driving force control unit DCU of the present embodiment
If the travel range is selected in the transmission 3 even when the accelerator pedal is released at a predetermined vehicle speed or less and the accelerator pedal is released, the driving force is transmitted from the motor 1 to the drive wheels 8 and the brake pedal BP is depressed. When the brake pedal BP is depressed, the driving force transmitted to the drive wheels 8 is set to a "small state", and when the brake pedal BP is not depressed, the driving force is set to a "large state". . Thus, the brake pedal BP
The driving force is set to the “small state” when the driver depresses the vehicle so that the driver does not depress the brake pedal BP so that the vehicle does not retreat due to its own weight when stopping on a slope even if the driving force by the engine 1 disappears. To do that. On the other hand, the reason why the driving force is set to the “large state” when the brake pedal BP is released is to prepare for starting and acceleration of the vehicle and to be able to withstand a certain amount of slope without relying on the braking force. is there.

The driving force control device DC according to the present embodiment
The driving force of creep by U has three magnitudes: a large state and a small state, and an intermediate state between the large state and the small state. The driving force transmission capacity in each state is preset to be large when the driving force is large, small when the driving force is small, and to an intermediate value when the driving force is an intermediate value. In this embodiment, a state in which the driving force (driving force of creep) is large is a strong creep state, a state in which the driving force is small is a weak creep state, and a state in which the driving force is intermediate between the large state and the small state is medium creep. Called state. Further, the strong creep state includes a level at which the driving force is large and a level at which the driving force is small. A large level is simply called a strong creep state, and a small level is called a strong creep state during running. The strong creep state is a state having a driving force balanced with the inclination of 5 °. The running strong creep state is a driving force smaller than the strong creep state and is a state before switching to the weak creep state (the driving force in the claims does not include the running strong creep state). The weak creep state is a state where there is almost no driving force. The medium creep state is a state in which the driving force is intermediate between the strong creep state and the weak creep state, and is an intermediate state in which the driving force is reduced stepwise in the process of switching from the strong creep state to the weak creep state. . The strong creep state is realized when the depression of the accelerator pedal is released below a predetermined vehicle speed (that is, in the idling state) and the travel range is selected by the position switch PSW. Proceed slowly as if crawling. The weak creep state is realized when the brake pedal BP is further depressed, and the vehicle is stopped or at a very low speed. In addition,
"The travel range is selected by the position switch PSW."
Means that the traveling range is selected in the transmission.

[Position Switch] The range of the position switch PSW is selected by a shift lever. The range of the position switch PSW is P
There are a range, an N range that is neutral, an R range used during reverse running, a D range used during normal running, and an L range used when sudden acceleration or strong engine braking is required. The traveling range is a range position where the vehicle can travel, and in this vehicle, there are three ranges of a D range, an L range, and an R range. Further, when the D range is selected by the position switch PSW, the mode switch MSW is used to set the D which is the normal driving mode.
Mode and S mode, which is a sport running mode, can be selected. Incidentally, information on the position switch PSW and the mode switch MSW is transmitted to the CVT ECU 6 and further transmitted to the meter 10. The meter 10 displays range information and mode information selected by the position switch PSW and the mode switch MSW. In the present embodiment, the aforementioned driving force of creep is reduced (that is, the driving force is set to a medium creep state or a weak creep state).
Is performed when the position switch PSW is in the D range or the L range, and when in the R range, the strong creep state is maintained. In the N range and the P range, the driving force is not transmitted to the driving wheels 8, 8, but the driving force transmission capacity is reduced and the mode is switched to a weak creep state in terms of form. These points will be described later in detail.

[ECUs] The FIECU included in the FI / MG ECU 4 controls the fuel injection amount so as to obtain an optimum air-fuel ratio, and controls the engine 1 in an integrated manner. The FIECU is transmitted with information indicating the throttle opening degree and the state of the engine 1, and controls the engine 1 based on each information. The MGECU included in the FI / MGECU 4 mainly controls 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. 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 starting of the engine 1 by the motor 2, 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, the driving force transmission capacity of the starting clutch, and the like. CVTE
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 CU 6, and control of the hydraulic pressure of each cylinder of the drive pulley and the driven pulley of the CVT 3 and control of the hydraulic pressure of the starting clutch are performed. To the CVT 3. Further, the CVT ECU 6 controls the proportional solenoid valves LSV (A), LS of the braking force holding device RU, which will be described in detail later.
ON (interruption) / OFF (communication) of V (B) (see FIG. 2)
Control unit CU for controlling the proportional solenoid valve LSV
(A), LSV (B) ON (cut off) / OFF (communication)
Is transmitted to the braking force holding device RU. In addition, the CVT ECU 6 determines the switching of the driving force of the creep, and also determines to increase the driving force when the vehicle movement (or the vehicle retreats) is detected during the operation of the braking force holding device RU, and the determination is made. Information CV
It transmits to the driving force control unit DCU of T3. Also, CVT
The ECU 6 includes a failure detection device DU for detecting a failure of the brake force holding device RU.

[Brake Apparatus] The disc brakes 9, 9, which are components of the brake apparatus, use a disc rotor that rotates integrally with the drive wheels 8, 8, and a wheel cylinder WC (see FIG. 2) as a drive source. It is sandwiched between brake pads and the braking force is obtained by the frictional force.

The master cylinder MC has a brake pedal B
This is a device that changes the stepping force of P to hydraulic pressure. Further, a master power MP is provided between the master cylinder MC and the brake pedal BP to assist the depressing force of the brake pedal BP. Master power MP
Is a device for increasing the braking force by adding a force such as a negative pressure of the engine 1 or compressed air to the force of the driver depressing the brake pedal BP, and reducing the pedaling force during braking. The brake switch BP is provided with a brake switch BSW, and detects whether the brake pedal BP is depressed or released.

Master cylinder MC and wheel cylinder W
Between C, a braking force holding device RU is provided. The brake force holding device RU keeps the brake force by applying the brake fluid pressure to the wheel cylinder WC even after the brake pedal BP is depressed and released. The brake force holding device RU includes a control unit CU in the CVT ECU 6 in its configuration. The configuration and the like of the brake force holding device RU will be described later in detail (see FIG. 2).

[Motor Stop Device] The motor stop device provided in this vehicle is composed of the FI / MGECU 4 and the like.
When the vehicle is stopped, the engine stop device is used to stop the engine 1
Can be automatically stopped. The motor stop device is
FI / MG ECU 4 and CVT ECU 6 determine an engine automatic stop condition. 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 / MGE
An engine stop command is transmitted from the CU 4 to the engine 1 to automatically stop the engine 1. The vehicle further improves fuel efficiency by automatically stopping the engine 1 by the motor stop device. When the engine 1 is automatically stopped by the prime mover stopping device, the FI / MG ECU 4 and the CVT ECU
At 6, the conditions for automatically starting the engine are determined. When the engine automatic start condition is satisfied, the FI / MG ECU 4
Transmits an engine start command to the MOTECU 5, further transmits a command to start the engine 1 from the MOTECU 5 to the motor 2, thereby automatically starting the engine 1 by the motor 2 and bringing the motor 1 into a strong creep state. The automatic engine start condition will be described later in detail.
Further, when the failure detection device DU detects a failure of the brake force holding device RU, the operation of the prime mover stopping device is prohibited.

[Signals] 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 a flag determined by the FI / MG ECU 4 in the engine automatic stop condition, and is a flag indicating whether or not all of the conditions are satisfied. The flag is 1 when the condition is satisfied, and is 0 when the condition is not satisfied. The engine automatic stop condition of F_MGSTB will be described later in detail. By the way, F
When both _MGSTB and F_CVTOK are switched to 1, the engine 1 is automatically stopped, and when either flag 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_MCRPON
Is a flag indicating whether or not the vehicle is in a medium creep state,
The value is 1 when in the middle creep state, and 0 when not in the middle creep state. When F_MCRPON is 1, the engine 1 is required to blow medium air (air weaker than strong creep) in the medium creep state. F_AIRSC
RP is a strong air request flag in a strong creep state,
The value is 1 when strong air is blown in the strong creep state, and 0 when strong air is not blown. Note that F_MCRPON and F_AI
When both RSCRP are 0, FI / MG ECU 4 blows weak air in the weak creep state. By the way, in order to keep the engine speed constant during idling regardless of the strong creep state, medium creep state, and weak creep state, blow air according to each state of strong creep state, middle creep state, weak creep state It is necessary to adjust the engine output. When the load of the engine 1 is high as in the strong creep state, it is necessary to blow strong air (strong air in the strong creep state). Note that blowing air means sending air from an air passage bypassing a throttle valve of the engine 1 to an intake pipe downstream of the throttle valve. The strength of the air is controlled by controlling the opening degree of the air passage to adjust the strength (amount) of the air to be sent. F_CVTOK is a flag that is determined by the CVT ECU 6 among the automatic engine stop conditions, and is a flag indicating whether or not all of the conditions are satisfied. The engine automatic stop condition of F_CVTOK will be described later in detail. F_CVTTO is CVT3
Is a flag indicating whether the oil temperature is equal to or higher than a predetermined value, and is 1 when the oil temperature is equal to or higher than the predetermined value, and is 0 when the oil temperature is lower than the predetermined value. In addition,
The oil temperature of the CVT 3 is estimated from the electric resistance value of the linear solenoid valve that controls the hydraulic pressure of the starting clutch of the CVT 3. F_POSR is a flag indicating whether the R range is selected in the range of the position switch PSW, and is 1 for the R range and 0 for other than the R range. F_POSDD is D range in the range of the position switch PSW and D in the mode of the mode switch MSW.
A flag indicating whether the mode has been selected.
The value is 1 for the mode D range and 0 for modes other than the D range D mode. When information indicating the D range D mode, the R range, the P range, and the N range has not been input, the FI / MGECU 4 determines that one of the D range S mode and the L range has been selected.

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 braking force 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 / MG ECU 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 with the position switch PSW, N or P
Is sent.

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 (that is, the driving force transmission capacity).

From the CVT ECU 6 to the braking force holding device R
The signal transmitted to U will be described. V_SOLA
Is the proportional solenoid valve LSV (A) of the brake force holding device RU
This is a control current for turning on (see FIG. 2) (closed, cutoff position) / OFF (open, communication position). Proportional solenoid valve LSV
When (A) is turned on, the current value of the control current is increased, and when it is turned off, the current value is decreased. Similarly, V_SOLB turns on the proportional solenoid valve LSV (B) (see FIG. 2) of the braking force holding device RU (closed / closed position).
/ OFF (open, communication position).
When the proportional solenoid valve LSV (B) is turned on, the current value of the control current is increased, and when it is turned off, the current value is decreased. Note that the control currents V_SOLA and V_SOLB
Can be continuously changed.

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,
Sent as position information.

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 (OF
F) is a flag that indicates 1) if it is depressed,
It is 0 when the depression is released.

The signal transmitted from CVT ECU 6 to meter 10 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. Further, D is set by the mode switch MSW.
Whether the mode (normal driving mode) or the S mode (sports driving mode) is selected is transmitted as mode information.

<< Brake Force Holding Device >> In the brake force holding device of the present invention, the brake force according to the depression force of the brake pedal before the depression is released continues to act on the vehicle even after the brake pedal is released. The braking force is maintained such that the braking force is maintained, and when the starting operation is performed, the holding of the braking force is released. When releasing the holding of the braking force, the releasing time of the braking force is controlled to be constant regardless of the magnitude of the holding braking force.

As shown in FIG. 2, the brake force holding device RU in the present embodiment is incorporated in a brake hydraulic passage FP of the hydraulic brake device BK, and the master cylinder M
C and a brake fluid pressure passage FP between the wheel cylinder WC and a blocking position where the brake fluid pressure passage FP is blocked to maintain the brake fluid pressure of the wheel cylinder WC (that is, to maintain the braking force). It has an alternative proportional solenoid valve LSV. Hereinafter, the brake device BK and the brake force holding device RU will be described in this order.

[Structure of Brake Apparatus] First, the brake apparatus BK will be described (see FIG. 2). In the present embodiment, the brake device BK is composed of a hydraulic brake device. The brake hydraulic circuit BC of the brake device BK includes a master cylinder MC, a wheel cylinder WC, and a brake hydraulic passage FP connecting the master cylinder MC and the wheel cylinder WC. Since the brake has an extremely important role for safe driving, the hydraulic brake device BK has two independent brake hydraulic circuits (BC (A) and BC (B)), and one of the systems has failed. Even at the moment, the rest of the system is designed to provide the minimum braking force. When the driver depresses the brake pedal BP, the depressing force is increased by the master power MP, and is converted into brake fluid pressure by the master cylinder MC.
The brake fluid pressure is transmitted to a wheel cylinder WC built in the brake 9 and is reconverted into a mechanical force. This mechanical force becomes a braking force for braking the drive wheels 8 and the like.

The main body of the master cylinder MC has a piston M
The CP is inserted and the driver
, The piston MCP is pushed and pressure is applied to the brake fluid in the master cylinder MC, and mechanical force is converted to brake fluid pressure (pressure applied to the brake fluid). When the driver releases his / her foot from the brake pedal BP and releases the depression, the piston MC is driven by the force of the return spring MCS.
P is restored, and at the same time, brake fluid pressure also returns. FIG.
The master cylinder MC shown in FIG. 2 has two pistons MCP arranged side by side from the viewpoint of fail-safe that two independent brake hydraulic circuits BC are provided.
Tandem type master cylinder M with C body divided into two
C.

In order to reduce the operating 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.
The operation of P is facilitated.

The brake fluid pressure passage FP connects the master cylinder MC and the wheel cylinder WC and the master cylinder M
The brake fluid pressure generated in C serves as a flow path for transmitting the brake fluid 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, the brake fluid pressure circuits BC are provided independently of each other, so that two independent brake fluid pressure passages FP are provided. The brake hydraulic circuit BC constituted by the brake hydraulic passage and the like shown in FIG.
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. It should be noted that the brake hydraulic circuit is not of the X-pipe type, but may be 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.

The wheel cylinder WC is provided for each wheel. The brake fluid pressure generated by the master cylinder MC and transmitted to the wheel cylinder WC through the brake fluid pressure passage FP is applied to a mechanical force (brake) for braking the wheel 8. Plays the role of converting into force). A piston is inserted into the main body of the wheel cylinder WC, and the piston is pressed by the brake fluid pressure to actuate a brake pad in the case of a disc brake and a brake shoe in the case of a drum brake to brake the wheels. Create braking force.
In addition to the above, a brake fluid pressure control valve for controlling the brake fluid pressure of the front wheel cylinder WC and the brake fluid pressure of the rear wheel cylinder WC is provided as necessary.

[Structure of brake force holding device (see FIG. 2)] Next, the brake force holding device RU will be described. The brake force holding device RU is incorporated in a brake fluid pressure passage FP connecting the master cylinder MC and the wheel cylinder WC of the brake device BK, and includes a proportional solenoid valve LSV, a brake fluid pressure gauge PG, and a control unit CU (built in the CVT ECU 6).
It is composed of

The proportional solenoid valve LSV is operated by a control current from the control unit CU. The proportional solenoid valve LSV has a blocking position for blocking the flow of the brake fluid, and a communication position for allowing the flow of the brake fluid. 1) When the proportional solenoid valve LSV is switched to the shut-off position, the flow of the brake fluid is shut off at once, and the brake fluid pressure applied to the wheel cylinder WC is held as the braking force. As long as the proportional solenoid valve LSV is in the shut-off position, the braking force is maintained. 2) When the proportional solenoid valve LSV is switched to the communication position, the flow of the brake fluid is allowed at a stretch and the braking force is released. As long as the proportional solenoid valve LSV is in the communicating position, the braking force is not maintained after the brake pedal BP is depressed and released. Further, as will be described later, 3) the proportional solenoid valve LSV can reduce the held braking force at an arbitrary speed by changing the current value of the supplied control current.

In the proportional solenoid valve LSV, the sum (+, hereinafter referred to as “biasing force or the like”) of the biasing force of the built-in spring S and the product of the pilot pressure applied to the valve multiplied by the pressure receiving area of the valve is given by The valve is opened and closed to balance the electromagnetic force generated by a built-in electromagnetic coil (not shown). If the proportional solenoid valve LSV is of the normally open type, the valve opens and becomes the communication position if the urging force or the like is larger than the electromagnetic force. The communication position is maintained until electromagnetic force> biasing force or the like. on the other hand,
If the urging force or the like is smaller than the electromagnetic force, the valve closes to the shutoff position. The cutoff position is maintained until electromagnetic force <biasing force or the like. The pilot pressure is a brake fluid pressure on the wheel cylinder WC side with respect to the proportional solenoid valve LSV.

The electromagnetic force of the proportional solenoid valve LSV can be changed according to the value of the control current supplied to the electromagnetic coil. Therefore, in the case of the normally open proportional solenoid valve LSV, if the current value is gradually reduced from the shut-off position where the current value is maximum, the electromagnetic force is gradually weakened. By repeating the opening and closing (communication position / blocking position), the brake fluid pressure held in the wheel cylinder WC can be gradually reduced. That is, the braking force acting on the vehicle can be gradually reduced. Further, the braking force can be released at a stretch by reducing the current value of the control current at a stretch. In addition,
In the case of the normally open proportional solenoid valve LSV, the communication position is when the current value supplied to the electromagnetic coil is zero (when it is small). The proportional solenoid valve LSV of the present embodiment is of a normally-open type (to prevent the brake fluid pressure passage FP from being shut off when the power supply is cut off due to a failure or the like).

By the proportional solenoid valve LSV, even when the driver releases the depression of the brake pedal BP when starting up a hill, the brake fluid pressure is held in the wheel cylinder WC (that is, the braking force is held) and the vehicle is prevented from moving backward. can do. Furthermore, the release time of the braking force can be kept constant irrespective of the magnitude of the braking force. Stability is improved. The operation of the proportional solenoid valve LSV is performed from the time the vehicle stops to the time when the vehicle starts moving.
Details will be described later.

The check valve CV serves to transmit the brake fluid pressure generated in the master cylinder MC to the wheel cylinder WC when the proportional solenoid valve LSV is in the shut-off position and the driver further depresses the brake pedal BP.
The check valve CV is activated effectively when the brake fluid pressure generated in the master cylinder MC exceeds the brake fluid pressure in the wheel cylinder WC, and the driver's brake pedal BP
The brake fluid pressure of the wheel cylinder WC is quickly increased in response to the increase in the pressure of the brake pedal. This allows the proportional solenoid valve LSV
, The braking force can be increased. Note that if the proportional solenoid valve LSV, which has been closed once, is brought into the communication position when the brake fluid pressure of the master cylinder MC exceeds the brake fluid pressure of the wheel cylinder WC, the brake pedal is provided only with the proportional solenoid valve LSV. BP
Check valve C
It is not necessary to provide V. That is, the brake fluid pressure value on the master cylinder MC side and the brake fluid pressure value on the wheel cylinder WC side are detected. , The check valve CV can be dispensed with.

The brake switch BSW detects whether or not the brake pedal BP is depressed, and transmits a detection signal to the control unit CU. Based on this detection signal and a detection signal such as an accelerator pedal depression state, the control unit C
U instructs the switching of the communication position and the cutoff position of the proportional solenoid valve LSV.

The brake fluid pressure gauge PG is provided at least on the wheel cylinder WC side. The brake fluid pressure gauge PG detects the brake fluid pressure and transmits a brake fluid pressure value converted into an electric signal to the control unit CU.

[Basic control of brake force holding device]
The basic control of the braking force holding device RU of the present embodiment will be described. 1) First, the braking force holding device RU switches the proportional solenoid valve LSV to the shut-off position on condition that the brake pedal BP is depressed when the vehicle is stopped. The condition "when the vehicle is stopped" is that if the proportional solenoid valve LSV is switched to the shut-off position when the vehicle speed is high, the vehicle may not be able to stop at the position desired by the driver.
This is because if the vehicle is stopped, even if the proportional solenoid valve LSV is in the shut-off position, there is no hindrance to the driver's operation. When the vehicle stops, this includes the state immediately before the vehicle stops. Further, the condition that "the brake pedal BP is depressed" means that in the situation where the brake pedal BP is not depressed, the braking force is not maintained even when the proportional solenoid valve LSV is in the shut-off position. This is because there is no point in setting the LSV to the blocking position. In addition to the above, when the fact that the driving force transmission capacity is in the “small state (weak creep state)” when holding the braking force is added to the condition that the proportional solenoid valve LSV switches to the shut-off position, the driver Is strongly brake pedal B
It is possible to stop firmly on a slope to step on P. Also, fuel economy can be reduced. The state where the driving force is small includes a state where the driving force is zero and a state where the engine 1 is stopped.

2) Subsequently, the braking force holding device RU
Holds the braking force so that the braking force according to the depression force of the brake pedal BP before the depression is released continues to act on the vehicle even after the depression of the brake pedal BP is released. "Even after the brake pedal BP is released"
This is because the release of the holding of the braking force along with the release of the brake pedal BP causes the vehicle to retreat. The “braking force according to the depressing force of the brake pedal BP” has the meaning of maintaining the braking force to such an extent that the retreat does not occur. Therefore, the brake force when the proportional solenoid valve LSV is at the shut-off position (the brake force after the brake pedal BP is increased when the brake pedal BP is further increased) is maintained as it is, the pressure is reduced and maintained, and the pressure is increased. And holding.

3) When the starting operation is performed, the holding of the braking force is released. When the "start operation" is performed, even if the holding of the braking force is released, smooth start can be performed while suppressing the retreat of the vehicle even on an uphill, in consideration of the driving force in the increasing process. The vehicle in the present embodiment is a vehicle in which the driving force control unit DCU increases the driving force transmission capacity such that the driving force is in a strong creep state by depressing and releasing the brake pedal BP. Therefore, the starting operation is regarded as the depressing release of the brake pedal BP and the subsequent achievement of the increase in the driving force. Achieving this increase in driving force
At some point after the driving force is generated and before the strong creep state is reached, releasing the brake force holding with only a small amount of driving force is convenient on downhill, It is not preferable on a hill because the vehicle may retreat. On the other hand, if the release of the braking force is performed in a state where the driving force is large, there is no problem on the uphill, but an abrupt feeling occurs on the downhill, which is not preferable.
Therefore, the stage at which the driving force is released from holding the braking force is determined by comparing the advantages and disadvantages of the uphill and downhill, together with the inertia force and rolling resistance of the vehicle. This point will be described later as “creep rising condition”.

[Control for Making Brake Force Release Time Constant] The brake force holding device RU of the present invention holds the brake force release time from the start of the reduction of the brake force to the end of the application of the brake force. Control is constant regardless of the magnitude of the braking force. That is, the driver adjusts the braking force according to the inclination angle of the vehicle (the gradient of the road) and stops. Specifically, on a steep slope, the brake pedal BP is strongly depressed to maintain the stopped state of the vehicle (high holding brake force). Maintained (small holding brake force). If the braking force is released uniformly in a situation where the magnitude of the holding brake force is different in this way, the point at which the braking force becomes zero will differ depending on the holding brake force, and the driver will perform the starting operation The time it takes to experience the initial movement of the vehicle will also differ.
However, by keeping the braking force release time constant irrespective of the magnitude of the holding brake force, the time from when the driver performs the start operation to when the driver feels the initial movement of the vehicle is always constant, and the time during the start operation is Stability is improved.

In the present embodiment, the control for keeping the release time of the braking force constant is performed by the control unit CU based on the preset release time and the held brake fluid pressure value from the brake fluid pressure gauge PG. Calculate the target reduction speed of the pressure value,
Based on the target reduction speed, the control unit CU reduces the current value of the control current supplied to the proportional solenoid valve LSV holding the braking force in accordance with the target reduction speed. The target reduction speed differs depending on the magnitude of the holding brake force (holding brake fluid pressure value). The target reduction speed increases as the holding brake force increases (the holding brake fluid pressure value increases). Conversely, as the holding brake force is smaller (the holding brake fluid pressure value is smaller), the target reduction speed is smaller.

The holding brake fluid pressure value is determined by the proportional solenoid valve LSV.
Is a brake fluid pressure value at an arbitrary point from the time when the start position is performed to the time when the start operation is performed. For example,
The brake fluid pressure value when the proportional solenoid valve LSV is in the shut-off position, the brake fluid pressure value when the brake switch BSW is turned off, the brake fluid pressure value at the maximum braking force when the vehicle is stopped, etc. It can be a pressure value. In the present embodiment, the brake fluid pressure value at the time when the start operation is performed is set as the holding brake fluid pressure value.

The release time is the time from when the release of the braking force is started until the braking force becomes zero. A long release time is not preferable because it gives the driver a sense of braking. On the other hand, when the release time is short, the time at which the release of the braking force is started is the time when a certain amount of driving force is generated (the time when the starting operation is performed). Can also. The release time in the present embodiment is a time from the time when the starting operation is performed to the time before and after the strong creep state is achieved.

{Specific Vehicle Control} Next, what kind of control is performed in the vehicle according to the present embodiment will be specifically described when the vehicle stops and when the vehicle starts. 3 to 9).

{Specific control when the vehicle is stopped} When the vehicle is stopped, 1) the condition that the brake force is held, 2) the condition that the operation of the brake force holding device is permitted, 3) the condition that the weak creep command is issued, and 4) The conditions under which a strong creep command is issued during running, the conditions under which a medium creep command is issued, and the conditions under which the engine is automatically stopped will be described in detail.

[1 Conditions for Holding Brake Force] Conditions for holding the brake force by the brake force holding device RU will be described. The braking force is maintained for the following 4
This is a case where all the conditions are satisfied (see FIG. 3A). I) The brake switch BSW is ON. II) The travel range is not any of neutral (N range), parking (P range), and reverse (R range). III) Operation for the brake force holding unit RU. IV) The vehicle speed is 0 km / h. When all these conditions are satisfied, the proportional solenoid valve LSV
Are in the shut-off position, and the braking force is maintained.

The conditions for maintaining the above-mentioned braking force will be described individually. I) The condition "the brake switch BSW is ON" is based on the reason that when the brake switch BSW is OFF, there is no or very little braking force to be held in the wheel cylinder WC.

II) The condition that the running range is not any of neutral (N range), parking (P range), and reverse (R range) is satisfied in N range and P range. This is because the strong creep state is maintained in the R range in order to eliminate useless operation, so that the vehicle is prevented from moving backward by the driving force in the strong creep state. Therefore, the braking force is maintained in the D range (drive range) and the L range (low range).

III) The condition that "the operation of the brake force holding device RU must be permitted" means that the driver depresses the brake pedal BP sufficiently hard before holding the brake force to prevent the driver from retreating on a slope. This is because it is necessary to secure the braking force that can be achieved. That is, in the strong creep state, the driver has the 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 the slope without stepping on P strongly. Therefore, when the driver
In some cases, P is depressed only weakly. However, in the weak creep state or the middle creep state, the vehicle does not have a driving force to prevent the vehicle from moving backward even on a slope having a slope of 5 degrees. Therefore, the driving force is weakened and the driver depresses the brake pedal BP appropriately in accordance with the slope, so that the braking force that can prevent the retreat on the slope even when the driving force decreases or disappears is secured. The control logic for permitting the operation of the brake force holding device RU will be described later.

IV) The condition "vehicle speed is 0 km / h" is because if the proportional solenoid valve LSV is set to the shut-off position during traveling, the vehicle cannot be stopped at an arbitrary position. On the other hand, if the vehicle speed is 0 km / h, the vehicle is in a stopped state, and there is no problem in driving operation even if the braking force is maintained. Note that “vehicle speed is 0 km / h” includes a state immediately before the vehicle stops.

[2 Conditions for Permitting Operation of Brake Force Holding Device] A condition for permitting operation of the brake force holding device RU, which is one of the conditions for holding the braking force, will be described. As shown in FIG. 3B, the operation of the brake force holding device RU is permitted in a weak creep state or a medium creep state. In other words, in the weak creep state or the middle creep state, the vehicle does not have a driving force to prevent the vehicle from moving backward even on a slope having a slope of 5 degrees. Therefore, before the braking force is held, the driver depresses the brake pedal BP appropriately in accordance with the sloping road to secure a braking force that can prevent the vehicle from moving backward on the sloping road, and holds the braking force to suppress the vehicle from moving backward. The driving force of the weak creep or the middle creep is determined based on a hydraulic pressure command value to the linear solenoid valve that controls the hydraulic pressure of the starting clutch of the CVT 3.

[3 Conditions for Issuing Weak Creep Command] The conditions for issuing a weak creep command will be described. The condition for issuing the weak creep command (F_WCRP) is when the following condition I) or II) is satisfied (FIG. 4 (a)).
reference). I) The transmission is in the N range or P range (NP range). II) Both of the following conditions are satisfied: 1) The brake force holding unit RU is normal, and 2) The brake switch BSW is ON, and 3) forward (DL) range,
And 4) The vehicle speed is 5km / h or less. 5) The vehicle speed> 5km / h and the vehicle speed> 4k after transition to the strong creep state.
m / h, or 6) weak creep state, or 7) vehicle speed is 0km / h, medium creep state, and a predetermined time has passed after transition to medium creep state

When any one of the above conditions I) and II) is satisfied, a weak creep command is issued and the vehicle enters a weak creep state. The above conditions are determined by the driving force control unit DCU. Also, to make the driving force weak creep state,
As described above, in addition to the reason that the driver depresses the brake pedal BP appropriately according to the slope (in accordance with the gradient of the stop location), the fuel consumption is reduced so that the vehicle does not retreat when stopping on the slope. There is also a reason to improve.

The conditions under which the above-described weak creep command is issued will be described individually. I) The condition "the transmission is in the N range or the P range" is that the accelerator pedal is quickly depressed at the same time as switching from the non-travel range (NP range) to the travel range (DL, R range). In this case, the driving force transmission capacity of the starting clutch is quickly increased, and a smooth start can be performed. That is, in the weak creep state, the hydraulic chamber of the starting clutch is already filled with the pressure oil, and there is no invalid stroke (play) of the pressing piston. Therefore, if the value of the pressure oil is increased, the driving force transmission capacity increases quickly. In addition, NP
Even if the range is set to the weak creep state in the range, this is because the driving force transmission capacity of the starting clutch is set to the capacity in the weak creep state in advance, and the driving force from the engine 1 is not transmitted to the drive wheels 8. In this regard, D.
This is different from the weak creep condition in the L range. By the way,
In the NP range, the connection between the engine 1 and the drive wheels 8 is completely interrupted by a forward / reverse switching mechanism arranged in series with the starting clutch on the driving force transmission path. That is, in the NP range, neither the forward driving force transmission path nor the reverse driving force transmission path is set. Therefore, no driving force is transmitted from the engine 1 to the driving wheels 8 at all.

The condition II) is a basic condition for the conditions 1) to 4) to be in the weak creep state, and the conditions before the weak creep state are the conditions 5) to 7) Either state is a condition for the weak creep state.

1) The condition "the brake force holding device RU is normal" means that the brake force cannot be held if the brake force holding device RU is abnormal, and if the brake force is not held, the vehicle may retreat on a slope in a weak creep state. Because it cannot be suppressed. For example, if there is an abnormality such as the proportional solenoid valve LSV not being at the shut-off position, and a weak creep command is issued and the vehicle enters a weak creep state,
After the brake pedal BP is depressed and released, the wheel cylinder WC does not hold the brake fluid pressure (the brake force is not held). Therefore, when the driver believes that the brake force holding device RU is activated when starting up a hill, and releases the depression of the brake pedal BP, the braking force is lost at once and the vehicle may retreat on the hill. In particular, if the braking force cannot be held, for example, when the driving force in the strong creep state after the brake pedal BP is depressed and released is set to be small on the premise that the braking force holding device RU is operated, the vehicle may retreat. easy. In this case, by maintaining the strong creep state, the vehicle is prevented from retreating on a sloping road, and the vehicle can be easily started uphill.

2) The condition that the brake switch BSW is ON is because the driver does not want to reduce the driving force at least when the brake pedal BP is not depressed.

3) The condition of "forward (DL) range" is for the purpose of improving fuel efficiency in the forward range. In the D range, a weak creep state is set in both the D mode and the S mode. By the way, R
In the range, the vehicle does not enter a weak creep state in order to facilitate garage entry due to strong creep traveling.

4) The condition that "the vehicle speed is 5 km / h or less"
At a vehicle speed exceeding 5 km / h, the reverse drive force from the drive wheels 8 can be transmitted to the engine 1 and the motor 2 via the starting clutch of the CVT 3 so that the engine brake is activated or the motor 2 generates regenerative power. Because there is.

5) “Vehicle speed after transition to strong creep state> 5 km / h
The condition of "vehicle speed> 4 km / h" is based on the reason that a weak creep state is obtained only by deceleration due to continuous brake depression. Since the driving force difference between the strong creep state and the weak creep state is large, if the vehicle is switched from the strong creep state to the weak creep state when the brake pedal BP is depressed, a strong deceleration unintended by the driver before the vehicle stops. Produces a feeling. In addition, when the vehicle is stopped and on an uphill, instantaneous retreat may occur. Therefore, it is necessary to prevent switching from the strong creep state to the weak creep state. Therefore, when the vehicle enters the strong creep condition, the vehicle speed exceeds 5 km / h, the throttle is turned off (the accelerator pedal is released), and the vehicle is not switched to the weak creep condition until the vehicle is switched to the strong creep condition during running.
Further, even if the vehicle speed exceeds 5 km / h and the driving force decreases after the vehicle enters a strong creep state (a strong creep state during running), for example, if the vehicle is approaching an uphill, the brake pedal BP is not depressed. Even so, the vehicle speed may decrease again to 5 km / h. At this time, the brake switch BSW is turned off.
Because of F, when the vehicle speed is reduced to 5 km / h, the vehicle enters a strong creep state. Even in such a case, in order to prevent the switching from the strong creep state to the weak creep state from being executed thereafter, a condition that the vehicle speed is greater than 4 km / h is provided, and when the vehicle speed decreases again to 5 km / h, the brake pedal BP If is not depressed, then the switch to the weak creep state is not executed. If the brake pedal BP is depressed when the vehicle speed has decreased to 5 km / h (the brake switch BSW is ON), switching from the strong creep state during running to the weak creep state is executed. That is, when the vehicle speed decreases again to 5 km / h (vehicle speed = 5
km / h), if you miss the opportunity to enter a weak creep condition,
Maintain strong creep as long as the speed is below km / h.

6) The condition of "weak creep state" is because once in the weak creep state, the conditions of 5) and 7) are excluded and the weak creep state is maintained. The condition 5) is set to a weak creep condition when the vehicle reaches 5 km / h, but the condition is not satisfied when the vehicle becomes lower than 5 km / h. Therefore, when the vehicle speed is lower than 5 km / h, 5)
It is not possible to maintain the weak creep condition only under the conditions described above. Therefore, in order to maintain the weak creep state even when the vehicle speed is less than 5 km / h, the weak creep state is a condition.

7) The condition that “the vehicle speed is 0 km / h, the medium creep state, and a predetermined time has elapsed since the transition to the medium creep state” is as follows.
This is a condition for setting the vehicle in a weak creep state in order to eliminate fuel consumption deterioration and vehicle body vibration when the vehicle is stopped in the strong creep state. When the vehicle speed decreases again to 5 km / h (vehicle speed = 5
km / h) to miss the opportunity to switch to the weak creep condition (conditions of 5), or after the brake pedal BP is released once the weak creep condition is reached and the vehicle enters the strong creep condition, the vehicle speed becomes 5 km / h. When h or less is maintained, the strong creep state is maintained. Further, if the vehicle stops in a strong creep state while the brake pedal BP is depressed, fuel efficiency deteriorates and vehicle body vibration continues. Therefore,
When the vehicle is completely stopped (vehicle speed = 0 km / h), the vehicle enters a medium creep state, which is a driving force intermediate between the strong creep state and the weak creep state, and furthermore, a predetermined time (eg, 300 msec) has passed,
Switch to weak creep condition. As described above, since the braking force is increased by depressing the brake pedal BP while the driving force is gradually lowered from the strong creep state to the medium creep state, and further to the weak creep state, an instant retreat on an uphill is also possible. It can be kept as small as possible.

[4 Conditions for Issuing a Strong Creep Command During Running] The conditions for issuing a strong creep command during running will be described. The strong creep command during running (F_MSCRP) is issued when both of the following conditions I) and II) are satisfied (see FIG. 4B). After a strong creep command during running, the vehicle enters a strong creep state during running. I) Vehicle speed> 5 km / h. II) Throttle is OFF (accelerator pedal is released). These conditions are determined by the driving force control unit DCU. In addition, the driving force is set to a strong creep state during running,
Strong deceleration feeling given to the driver before the vehicle stops, which occurs when switching from the strong creep state to the weak creep state,
Alternatively, this is to prevent instantaneous retreat when the vehicle is stopped and on an uphill. For this reason, the driving force is set to be smaller than the driving force in the strong creep state before entering the weak creep state.

The conditions under which the above-mentioned strong creep command during running is issued will be described individually. I) The condition that "vehicle speed> 5 km / h" means that when the vehicle transitions from the strong creep state to the weak creep state, the vehicle speed once exceeds 5 km / h after the transition to the strong creep state, and then becomes 5 km / h. This is because it is a condition to be in a weak creep state at the time of becoming. Further, this is for discriminating between a strong creep state at a vehicle speed of 5 km / h or less and a strong creep state at the time of running at a vehicle speed exceeding 5 km / h.

II) The condition "throttle is OFF (TH OFF)" is because the driver does not want to increase the driving force, and there is no problem even if the driving force is reduced.

[5 Conditions for Issuing Medium Creep Command] The conditions for issuing the medium creep command will be described. Conditions for issuing the medium creep command (F_MCRP) are as follows:
This is a case where all three conditions of I), II) and III) are satisfied (see FIG. 4 (c)). I) The brake switch BSW is ON. II) The vehicle is in the forward (DL) range. III) The vehicle is completely stopped (vehicle speed = 0 km / h). Is determined. In addition, the driving force is changed to the medium creep state when the vehicle speed is reduced to 5 km / h again (vehicle speed = 5 km / h) or the opportunity to switch to the weak creep state is missed, or once the weak creep state is reached. After the brake pedal BP was released and the vehicle was in a strong creep condition, the vehicle speed was 5km / h.
When the following is maintained, the strong creep state is maintained. Further, if the vehicle stops in the strong creep state, the fuel efficiency deteriorates and the body vibration continues. Therefore, if the vehicle is switched from the strong creep state to the weak creep state when the vehicle is stopped, instantaneous retreat occurs as described above. Therefore, the vehicle is switched to the medium creep state which is a driving force intermediate between the strong creep state and the weak creep state.

The conditions under which the above-described medium creep command is issued will be described individually. I) The condition that "the brake switch BSW is ON"
This is because when the brake pedal BP is not depressed, the driver does not want to at least reduce the driving force.

II) "Being in the forward (DL) range"
This is because the condition is set to a weak creep state in the D or L range, and it is necessary to set the medium creep state in this range. In the NP range, the transmission is switched to the weak creep state at the same time as the transmission is switched, so there is no need to set the medium creep state. Further, in the R range, there is no need to set the medium creep state to maintain the strong creep state.

III) "Complete vehicle stop (that is, vehicle speed =
0 km / h), the condition is a weak creep state in order to suppress the deterioration of fuel consumption and the body vibration in a strong creep state when the vehicle is stopped. For that reason.

Whether the vehicle is in the weak creep state, the strong creep state during running, or the middle creep state is determined by the hydraulic pressure command value for the starting clutch of the CVT 3.

[6 Engine Automatic Stop Condition] In order to further improve fuel efficiency, the engine 1 is automatically stopped when the vehicle stops. This condition will be described. When all the conditions shown in FIG. 5 are satisfied, an engine stop command (F_EN
GOFF) is issued, and the engine 1 automatically stops. 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. The automatic stop condition of the engine 1 is determined by the FI / MG ECU 4 and the CVT ECU 6, and determined by the FI / MG ECU 4 and when all of the conditions I) to VIII) are satisfied, F_MGSTB becomes 1 and C_MGSTB becomes 1.
When all of the conditions IX) to XV) are determined by the VT ECU 6, F_CVTOK becomes 1.

The conditions for automatically stopping the engine will be described individually. I) The condition "the brake switch BSW is ON" is for the purpose of calling 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 depression of the brake pedal BP.

II) The condition that “the water temperature of the engine 1 is equal to or higher than a predetermined value” 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.

III) "After starting the engine 1, once the vehicle speed is 5 k
m / h or more "is for facilitating garage departure and entry during creep running. This is because it is troublesome if the engine 1 is automatically stopped every time the vehicle is stopped due to a turning operation when the vehicle is taken in and out of the garage.

IV) The range is other than the R / D (S mode) / L range (ie, ND (D mode) /
The condition “P range)” is based on the following reason. This is because, when the position switch PSW is in the R range or the L range, it is troublesome if the engine 1 is automatically stopped frequently when entering the garage. When the position switch PSW is in the D range and the mode switch MSW is in the S mode,
This is because the driver expects that the vehicle can be started quickly in the D range S mode.

V) The condition that "the battery capacity is equal to or more than a predetermined value" is for the purpose of preventing the engine 2 from being unable to restart the engine 1 after the engine 1 is stopped.

VI) The condition of "not more than the predetermined value of the electric load" is for the purpose of ensuring the supply of electricity to the load.

VII) The condition that the negative pressure in the constant-pressure chamber of the master power MP is equal to or higher than a predetermined value is satisfied when the negative pressure in the constant-pressure chamber of the master power MP is small and the depressing force when the brake pedal BP is depressed. Because the amplification of the brake becomes small and the effectiveness of the brake decreases (it is not assisted),
For that reason. That is, when the engine 1 is stopped in a state where the negative pressure of the constant pressure chamber is small, the negative pressure of the constant pressure chamber is further reduced because the negative pressure of the constant pressure chamber is introduced from the intake pipe of the engine 1. Therefore, the amplification of the depression force when the brake pedal BP is depressed is reduced, and the braking force is reduced.

VIII) The condition that the accelerator pedal is not depressed (TH OFF) is because the driver does not want to increase the driving force and there is no problem even if the engine 1 is stopped. .

IX) "Engine 1 in FI / MG ECU 4"
That the automatic stop condition of the engine 1 is satisfied and all the automatic stop conditions of the engine 1 are completed. " Not because of that.

X) The condition "vehicle speed is 0 km / h" is because there is no problem even if the driving force is lost if the vehicle is stopped.

XI) The condition that "the ratio of CVT3 is low" is that if the ratio (pulley ratio) of CVT3 is not low, it may not be possible to start smoothly.
For that reason.

XII) The condition that “the oil temperature of the CVT 3 is equal to or higher than a predetermined value” is satisfied when the oil temperature of the CVT 3 is low.
This is because the actual hydraulic pressure rise of the starting clutch is delayed, and it takes time from the start of the engine 1 to the strong creep state, and the vehicle may retreat on a slope.

XIII) The condition that the accelerator pedal is not depressed (TH OFF) is because the driver does not want to increase the driving force and there is no problem even if the engine 1 is stopped. .

XIV) The condition "the brake force holding device RU is normal" means that if the brake force holding device RU is abnormal, the braking force cannot be held in some cases. To prevent the vehicle from moving backward on a slope.

XV) "(1) Holding brake force (proportional solenoid valve L
SV is in the cutoff position) and the brake switch BSW is ON.
Or [2) NP range] for the following reasons. 1) When the braking force is held, even if the engine 1 automatically stops and the driving force is lost, the vehicle does not retreat on an uphill. Further, 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. 2) When the vehicle is stopped with the position switch PSW in the P range or the N range, the driver does not stop the engine 1 because the driver intends to stop the vehicle completely. Under this condition, the engine 1 is automatically stopped even when the braking force holding device RU is not operating.

{Specific control when starting the vehicle} When starting the vehicle, 1) the condition for releasing the holding of the braking force, 2) the condition for judging the start of creep, 3) the condition for issuing a strong creep command, and 4) the automatic start of the engine. Each condition will be described in detail.

[1 Conditions for releasing the holding of the braking force]
The conditions under which the holding of the braking force by the braking force holding device RU is released will be described. As shown in FIG. 6A, the holding of the braking force is released when any of the following conditions is satisfied. I) N / P range and brake switch BSW is OFF
II) The delay time has elapsed since the brake switch BSW was turned off. III) The creep rise and the brake switch BSW
Is OFF. IV) The vehicle speed exceeds 20 km / h. When any of these conditions is satisfied, the proportional solenoid valve LSV is brought into the communicating position, and the holding of the braking force is released.

The conditions for releasing the holding of the braking force will be described individually. I) "NP range and brake switch BSW is OFF"
F ”is the condition that the brake force holding device RU
This is because the useless operation is omitted.

II) The condition that “the delay time has elapsed since the brake switch BSW was turned off” means that the brake force was held as long as the brake pedal BP was released as a fail-and-safe action. This is because it is not preferable to cause the dragging of the brake. In the present embodiment, the delay time (TMBKDLY) is determined when the brake pedal BP is released (when the brake switch BSW is turned off).
About 2 seconds from the time of).

III) The condition of "creep rising and the brake switch BSW being OFF" is a process in which the driving force increases to the strong creep state, and the vehicle has not reached the strong creep state, Considering the inertia force and the rolling resistance (plus the driving force in the increasing process) of the vehicle, the vehicle can be prevented from retreating, and the vehicle can be started without a sudden feeling on a downhill.

IV) The condition "vehicle speed exceeds 20 km / h" is for fail-safe action in order to eliminate unnecessary brake dragging.

However, when releasing the holding of the braking force under the condition of the above III), the releasing of the braking force is performed so as to be constant regardless of the magnitude of the holding braking force. That is, the control unit CU calculates the target reduction speed of the brake fluid pressure value from the preset release time and the held brake fluid pressure value, and according to the target reduction speed, the proportional solenoid valve LSV
The current value of the control current supplied to is decreased. II above
Under conditions other than I), the control unit CU sets the proportional solenoid valve LSV
The instantaneous release of the holding brake force is achieved by immediately reducing the current value of the control current supplied to the vehicle.

[2 Conditions for Judgment of Creep Rise] The judgment conditions for creep rise, which is one of the conditions for releasing the holding of the braking force, will be described. It is determined that creep has risen when one of the following I) or II) is satisfied (see FIG. 6 (b)). I) The hydraulic command value of the starting clutch of the CVT 3 is equal to or greater than a predetermined value. II) The engine 1 is restarted after the automatic stop and a predetermined time has elapsed. These two conditions are determined by the driving force control unit DCU. . When the creep rises, the brake force holding device R
Even when the operation of U is released and the braking force is lost, the driving force is increased to such an extent that the retreat on an uphill can be suppressed in consideration of the inertia force and the rolling resistance (plus the driving force in the increasing process) of the vehicle. It is in the state of doing. The creep rise includes a state in which the driving force is increased to such an extent that the retreat can be suppressed to a minimum by the increased driving force even if the vehicle slightly retreats.

The conditions for judging the rise of creep will be described individually. I) The condition that “the hydraulic command value of the starting clutch of the CVT 3 is equal to or more than a predetermined value” is based on the reason that the holding of the braking force is canceled if the hydraulic command value of the starting clutch of the CVT 3 is equal to or more than the predetermined value. It is determined that the driving force is increased to such an extent that the vehicle can be prevented from retreating on an uphill. In addition, the reason is that a smooth start without a sudden feeling can be performed even on a downhill. In addition, when the hydraulic command value of the starting clutch is equal to or more than the predetermined value, the hydraulic command value to the linear solenoid valve that controls the hydraulic pressure of the engaging force of the starting clutch is determined to be weak creep in the process of shifting from the weak creep state to the strong creep state. This is the point in time when it has increased to a value approximately in the middle of the strong creep.

II) The condition that "the engine 1 is restarted after the automatic stop and a predetermined time has elapsed" is that if the engine 1 is restarted after the automatic stop and the predetermined time has passed, the above-mentioned condition is maintained even if the holding of the braking force is released. For this reason, it is determined that the driving force has increased to such an extent that the vehicle can be prevented from retreating on an uphill slope. Another reason is that the vehicle can be started smoothly without a sudden feeling on a downhill. The predetermined time is counted from the time when the engine 1 is actually restarted and the supply of the pressure oil to the starting clutch of the CVT 3 is started. This is because when the engine 1 is stopped, the hydraulic oil in the hydraulic chamber of the starting clutch of the CVT 3 is leaked, and when the engine 1 is started and the supply of the pressure oil is started, the invalid stroke (play) of the pressing piston is caused. There is. Therefore, the hydraulic pressure command value to the linear solenoid valve of the starting clutch does not match the actual hydraulic pressure value (driving force transmission capacity). As a result, when the driving force increases from the stop state of the engine 1, it is not possible to determine the creep start from the hydraulic command value of the starting clutch of the CVT 3. Therefore, when shifting from the stopped state of the engine 1 to the strong creep state, the timer starts counting the supply of the pressure oil to the starting clutch (creep rising timer) to determine the creep rising.

[3 Conditions for Issuing Strong Creep Command] Conditions for issuing a strong creep command will be described. The strong creep command (F_SCRP) is shown in FIG.
It is emitted when the condition shown in (b) is satisfied, and enters a strong creep state.

The first condition for issuing the strong creep command is as follows:
This is the case where either of the following I) or II) is satisfied (see FIG. 7A). I) [1) Brake switch is OFF or throttle is O
N and forward (D / L) range] or [2) reverse (R) range], and 3) vehicle speed is 5 km / h or less. II) Vehicle retreat is detected.

Alternatively, the second condition for issuing the strong creep command is when one of the following III) or IV) is satisfied (see FIG. 7 (b)). III) [1) Brake switch is OFF or throttle is ON and forward (D / L) range] or [2) Reverse (R)
Range] and 3) The vehicle speed is 5 km / h or less. IV) The vehicle must be completely stopped before the vehicle speed pulse is input and the vehicle speed pulse is input.

Incidentally, the first condition and the second condition under which the strong creep command is issued are the same as the conditions I) and III), but different from the conditions II) and IV). Therefore, I)
Description of the condition III) that is the same as the condition III) is omitted. In addition,
These conditions are determined by the driving force control unit DCU.

The conditions under which the strong creep command is issued will be described individually. First, the conditions 1) to 3) of I) will be described (note that the contents are the same as those of III), so the description of III) is omitted). 1) "Brake switch is off or throttle is on
And the forward (D / L) range "is a condition in which the driver shifts to the starting operation and shifts to the strong creep state.
For that reason. That is, the driver sets the position switch PSW to the D range or the L range,
Since the depression of the brake pedal BP is released or the accelerator pedal is depressed, there is an intention to start. Therefore, the state is switched from the weak creep state to the strong creep state. When the accelerator pedal is depressed, the driving force transmission capacity after the driving force transmission capacity reaches a large state increases to a capacity that can transmit all of the driving force generated by the prime mover (a state larger than the large state). Is done. However, the strong creep flag (F_SCRPON) continues to be raised until another flag is raised next. 2) The condition of "reverse (R) range" is for the purpose of smooth creep running in the R range. That is, when the driver switches the position switch PSW to the R range, the driver may want to enter a garage or the like by running with a strong creep driving force. Therefore, the state is switched from the weak creep state to the strong creep state. 3) The condition that the vehicle speed is 5 km / h or less is for the purpose of judging the strong creep condition during traveling when the vehicle speed exceeds 5 km / h and the strong creep condition when the vehicle speed is 5 km / h or less.

II) The condition of "vehicle retreat detection" is that when the vehicle is moving backward on a steep uphill with the moving force due to the vehicle's own weight exceeding the braking force, the vehicle is starting to retreat, and the driving force in the strong creep state suppresses the retreat. To do that. In the case of an uphill, the sum of the driving force in the weak creep state (the driving force is zero when the engine 1 is stopped) and the braking force is the braking force against the moving force due to the vehicle's own weight.
However, as the slope becomes steeper, the moving force of the vehicle due to its own weight increases. Therefore, on a steep ascending slope, the moving force of the vehicle due to its own weight exceeds the sum of the driving force and the braking force in the weak creep state, and the vehicle moves backward. Therefore, when the vehicle is detected to move backward, the vehicle is unconditionally changed from the weak creep state to the strong creep state to generate a driving force against an uphill.

Here, the means for detecting the backward movement of the vehicle will be described with reference to FIG. For example, the helical gears HG (A), HG are located downstream of the starting clutch of CVT3.
(B) is provided. The helical gears HG (A), HG
The position where (B) is provided should just be a position which rotates with a tire. As shown in FIG. 8A, the helical gear HG
(A) and HG (B) have spiral teeth and are obliquely cut in the circumferential direction. Therefore, the phase of the tooth is shifted depending on the direction of the tooth or the rotational direction of the direction. Therefore,
Electromagnetic pickups P (A) and P (B) are provided on the same axis AX of the helical gears HG (A) and HG (B), and the tip of the tooth is detected by the electromagnetic pickups P (A) and P (B). . Then, the electromagnetic pickups P (A) and P (B)
The rotational direction is determined from the position of the pulse phase difference on the basis of the two pulses detected in (1). By the way, when rotating in the direction, as shown in FIG. 8B, the pulse detected by the electromagnetic pickup P (B) is
The pulse is shifted backward from the pulse detected in (A). That is, the tips of the teeth of the helical gear HG (A) are detected earlier than the tips of the teeth of the helical gear HG (B). On the other hand,
When rotating in the direction, as shown in FIG. 8C, the detected pulse detected by the electromagnetic pickup P (B) is shifted forward from the pulse detected by the electromagnetic pickup P (A).
That is, the tips of the teeth of the helical gear HG (A) are detected after the tips of the teeth of the helical gear HG (B). Thus, the rotation direction can be detected from the position of the pulse phase difference. Therefore, for example, in the case where the rotation in the direction is the backward movement of the vehicle, if the pulse detected by the electromagnetic pickup P (B) is shifted backward from the pulse detected by the electromagnetic pickup P (A), it is determined that the vehicle is moving backward. Although the helical gears HG (A) and HG (B) are used, any gear may be used as long as there is a phase difference between the teeth of the two gears.

IV) The condition that "the vehicle is completely stopped before the vehicle speed pulse is input and the vehicle speed pulse is input" is that if the vehicle moves even a little from the completely stopped state, the vehicle may retreat (retreat). And there is a strong creep condition to resist the slope. That is, it is not determined whether the vehicle has moved forward or backward, but the time when the vehicle has moved is determined. In the case of a slope, the sum of the driving force of weak creep (the driving force is zero when the engine 1 is stopped) and the braking force is the braking force against the moving force due to the vehicle's own weight. However, as the slope becomes steeper, the moving force due to its own weight increases. Therefore, on a steep hill, the moving force of the vehicle due to its own weight exceeds the sum of the driving force and the braking force of the weak creep, and the vehicle may move forward (downhill) or retreat (uphill). Therefore, the forward or backward movement of the vehicle (that is, the movement of the vehicle) is detected, the weak creep state is changed to the strong creep state, and a driving force against a slope is generated.
First, before the vehicle speed pulse is input, it detects that the vehicle speed pulse is 0 pulse, and detects that the vehicle is completely stopped. Thereafter, when even one pulse of the vehicle speed is input, it is determined that the vehicle has moved. It should be noted that even when the vehicle travels in the direction intended by the driver, setting the driving force in the strong creep state does not adversely affect the driver's will, so there is no problem.

[4 Engine Automatic Start Conditions] Engine 1
After the automatic stop, the conditions for automatically starting the engine 1 will be described. When the conditions shown in FIG. 9A or 9B are satisfied, an engine start command (F_ENGON) is issued, and the engine 1 starts automatically. The automatic start of the engine 1 is performed by a motor stop device. Therefore, the following engine automatic start conditions are determined by the motor stop device. The automatic start condition of the engine 1 is FI /
MG / ECU 4 and CVT ECU 6 determine FI / MG
If any of the conditions I) to VI) is satisfied as determined by the ECU 4, F_MGSTB becomes 0, and the CVT ECU 6
VII) to XI) [or VII) to X) and XI
F) If any of the conditions is satisfied, F_CVTOK becomes 0. Incidentally, the first condition (the condition shown in FIG. 9A) and the second condition (the condition shown in FIG. 9B) at which the automatic start condition of the engine 1 is issued are XI determined by the CVT ECU 6; XII) The only difference is the vehicle stop condition before the vehicle speed pulse is input and the vehicle speed pulse is input. Therefore, only the second condition under which the automatic start condition of the engine 1 is issued will be described.

I) "The brake pedal BP is released (that is, the brake switch BSW is
FF) "is based on the reason that it is determined that the driver's start operation has been started by releasing the brake pedal. That is, in the case of the D range D mode, the driver releases the depression of the brake pedal BP when the start operation is started.
The engine 1 is automatically started. In the P range and the N range, the driver releases the depression of the brake pedal BP in order to get out of the vehicle. In this case, the driver does not need to turn off the ignition switch due to the automatic stop of the engine 1. Then, the engine 1 is automatically started so as not to leave the vehicle.

II) The condition "switched to the R / D (S mode) / L range" means that after the engine 1 is automatically stopped, the transmission is switched to the R / D (S mode) / L range. Switching is because the driver is deemed to have an intention to start immediately. Therefore, after the engine 1 automatically stops in a range other than the RD (S mode) and the L range, the RD
(S mode)-When switched to the L range, the engine 1 is automatically started.

III) The condition that the battery capacity is equal to or less than the predetermined value is because the engine 1 cannot be automatically started when the battery capacity is reduced, which is prevented. That is, unless the battery capacity is equal to or greater than the predetermined value, the engine 1 is not automatically stopped. However, even after the engine 1 is automatically stopped, the battery capacity may be reduced. In this case, the engine 1 is automatically started for the purpose of charging the battery. Note that 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.

IV) "Electric load is not less than a predetermined value"
This is because, for example, when 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.

V) The condition that "the negative pressure of the master power MP is equal to or less than a predetermined value" is because the braking force of the brake decreases as the negative pressure of the master power MP decreases. Therefore, when the negative pressure of the master power MP falls below a predetermined value, the engine 1 is automatically started.

VI) The condition "the accelerator pedal is depressed (TH ON)" is because the driver expects the driving force of the engine 1. Therefore, when the accelerator pedal is depressed, the engine 1 is automatically started.

VII) The condition that “the automatic start condition of the engine 1 in the FI / MG ECU 4 is satisfied”
This is because the CVT ECU 6 also determines the automatic start condition of the engine 1 determined by the FI / MG ECU 4.

VIII) The condition that the accelerator pedal is depressed (TH ON) is because the driver expects the driving force of the engine 1. Therefore, when the accelerator pedal is depressed, the engine 1 is automatically started.

IX) "The brake pedal BP is released (that is, the brake switch BSW
Is OFF) ", because it is determined that the driver's starting operation has been started by depressing the brake pedal BP. That is, in the case of the D range D mode, the driver releases the depression of the brake pedal BP when the start operation is started, so that the engine 1 is automatically started.

X) The condition that "the braking force holding device RU is faulty" means that the driver believes that the braking force is held when the braking force holding device RU does not hold the braking force due to the failure. If the driving operation of the vehicle is performed, when the engine 1 is stopped, there is a possibility that the vehicle may retreat (forward) on a slope. Therefore, when the proportional solenoid valve LSV or the like is out of order,
The engine 1 is automatically started to create a strong creep condition.
If a failure is detected in the braking force holding unit RU after the engine 1 is automatically stopped, the braking force may not be able to be held when the brake pedal BP is released when the vehicle starts moving, so that strong creep may occur. The engine 1 is automatically started when a failure is detected in order to set the state. That is, the vehicle is prevented from moving backward in the strong creep state, and the vehicle is easily started uphill. The failure detection of the brake force holding device RU is performed by the failure detection device DU.

XI) The condition of "vehicle retreat detection" is that the vehicle starts retreating on a steep uphill because the moving force due to the vehicle's own weight exceeds the braking force and the vehicle starts to retreat.
The retraction is suppressed by the driving force of the above. In the case of an uphill, when the engine 1 is stopped, the braking force becomes a braking force against the moving force due to the weight of the vehicle. However, as the slope becomes steeper, the moving force due to its own weight increases. Therefore, on a steep uphill, the moving force of the vehicle due to its own weight exceeds the braking force, and the vehicle may retreat. Therefore, when the vehicle is moved backward, the engine 1 is unconditionally changed from the stopped state to the strong creep state to generate a driving force against an uphill. The method of detecting the backward movement of the vehicle has been described on the condition that the strong creep command is issued, and thus the description thereof is omitted.

XII) The condition that the vehicle is completely stopped before the vehicle speed pulse is input and the vehicle speed pulse is input is a condition that the vehicle moves backward even if it moves a little from the completely stopped state (the vehicle may retreat). The engine 1 is automatically started and the driving force is used to resist the slope. That is, it is not determined whether the vehicle has moved forward or backward, but the time when the vehicle has moved is determined. In the case of a slope, when the engine 1 is stopped, only the braking force is the braking force against the moving force due to the vehicle's own weight. However, as the slope becomes steeper, the moving force due to its own weight increases. Therefore, on a steep slope, the moving force of the vehicle due to its own weight exceeds the braking force, and the vehicle may move forward (downhill) or retreat (uphill). Therefore, the forward or backward movement of the vehicle (that is, the movement of the vehicle) is detected, and the engine 1 is automatically started (creating a strong creep state) to resist the slope. First,
Before the vehicle speed pulse is input, it detects that the vehicle speed pulse is 0 pulse, and detects that the vehicle is completely stopped. Thereafter, when even one pulse of the vehicle speed is input, it is determined that the vehicle has moved.

{Control Time Chart} Next, with reference to FIGS. 11 and 12, it will be described how the vehicle having the above-mentioned system configuration is controlled, for example, during traveling (deceleration → stop → start). This will be specifically described. FIG. 11 is a control time chart when the engine 1 does not automatically stop when the vehicle stops, and FIG. 12 is a control time chart when the engine 1 automatically stops when the vehicle stops.

The braking force holding device RU of the present embodiment performs an operation based on a control flowchart illustrated in FIG. That is, the system waits for the brake pedal BP to be depressed and the brake switch BSW to be turned on while the vehicle is running (S1), waits for the vehicle to stop when the brake switch BSW is turned on (S2), and applies the braking force when the vehicle stops. The holding device RU holds the braking force (S3). That is, the proportional solenoid valve LSV is in the shut-off position.
Next, the process waits until the brake pedal BP is released when the vehicle starts and the brake switch BSW is turned off (S4). When the brake switch BSW is turned off, the driving force rises to the driving force in the strong creep state, but waits for the creep to rise (S5). If it is determined that the creep has risen, the target reduction speed of the braking force is set to a predetermined release time. The braking force is calculated from the holding brake fluid pressure value at the time when it is determined that creep has risen (S6), and the braking force is released with the release time kept constant irrespective of the magnitude of the holding brake force (S7).

[Control time chart (1), see FIG. 11] The control time chart (1) shows the case where the holding brake force when the vehicle is stopped is large (corresponding to a steep slope, braking force 1), and when the vehicle is medium. (Corresponding to a middle slope, braking force 2) and small (corresponding to a flat road, braking force 3). The thick line in FIG. 11 indicates the driving force, and the thin line indicates the braking force.

The vehicle in the control time chart (1) does not automatically stop the engine 1 when the vehicle stops. The position switch PSW and the mode switch MSW of the vehicle are not changed in the D mode D range.

First, when the vehicle is running (by the way, vehicle speed> 5 km
/ h), when the driver releases the accelerator pedal (ie, when the throttle is turned off), the driving force control unit DCU issues a strong creep command during driving (F_MSCR).
P) and a strong creep condition during running (F_MSCRPO)
N). Therefore, a strong creep state (F_SCRP
ON), the driving force decreases.

Further, when the driver releases the depression of the accelerator pedal and depresses the brake pedal BP (that is, when the brake switch BSW is turned on), the braking force increases. Then, when the brake pedal BP is continuously depressed and the vehicle speed becomes 5 km / h,
The driving force control unit DCU issues a weak creep command (F_WCR
P) to make a weak creep state (F_WCRPON). At this time, the driver changes from the strong creep state to the weak creep state during running, so that the driver does not feel a strong deceleration feeling.

When the vehicle speed becomes 0 km / h, the braking force holding device RU holds the braking force by setting the proportional solenoid valve LSV to the shut-off position. When the vehicle stops, the driver depresses the brake pedal BP according to the gradient of the stop location, so that the holding brake force at the time of stopping the vehicle also corresponds to the gradient. That is, the holding brake force is large on a steep slope (braking force 1), the holding braking force is medium on a middle slope (braking force 2), and the holding braking force is small on a flat road (braking force 3).

Next, the driver releases the brake pedal BP in preparation for the restart. When the brake switch BSW is turned off, a strong creep command is issued (F
_SCRP) The driving force increases. When the driving force increases to about half of the driving force value in the weak creep state and the driving force value in the strong creep state, it is determined that creep has started (F_SCDLY). At the start of creep, no driving force is generated to the extent that it resists a steep slope. However, considering the inertial force acting on the vehicle, the rolling resistance of the driving wheels 8 and the like, and the driving force in the ascending process, the braking force is increased. Even if the vehicle speed is reduced, the vehicle does not retreat immediately. Therefore, the release of the holding brake force is started at the time of creep rising (F_SCDLY).

The release of the braking force is determined by the brake fluid pressure value (holding brake fluid pressure value) at the time when it is determined that creep has risen.
The control unit CU calculates a target reduction speed for reducing the holding brake force from the preset release time and the current value of the control current supplied to the proportional solenoid valve LSV according to the target reduction speed. Is performed by reducing
As a result, the braking force is released in a fixed time regardless of the magnitude of the holding brake force. The magnitude of the target reduction speed is in the order of braking force 1> braking force 2> braking force 3, and the target reduction speed is smallest in the case of braking force 3 (flat road). In this case, the braking force decreases linearly (linear reduction pattern).

Then, when the driving force increases and enters a strong creep state (F_SCRPON), a sufficient driving force is generated. For this reason, in the present embodiment, regardless of the magnitude of the holding brake force, before and after the strong creep state (F_
The release time is set so that the current value of the control current supplied to the proportional solenoid valve LSV becomes zero (near SCRPON) and the holding brake force is released. Thereafter, the driving force increases due to depression of the accelerator pedal, and the vehicle accelerates.

In this embodiment, the current value of the control current supplied to the proportional solenoid valve LSV at the time when the proportional solenoid valve LSV is at the shut-off position depends on the magnitude of the braking force when the vehicle stops. And always the maximum current value, and this current value is maintained until the creep rise. Therefore, if the current value of the control current is reduced from the maximum current value according to each target reduction speed, the release time will be different. In the case of FIG. 11, when the holding brake force is small, the braking force 3 requires a long time until the braking force is released. Therefore, the control unit CU
Reduces the control current at once to the current value corresponding to the holding brake fluid pressure value at the time of creep rise, that is,
The control current is reduced at a stretch to a current value at which the electromagnetic force of the proportional solenoid valve LSV and the spring force are balanced (adjustment of the control current), and then the holding brake force is reduced at each target reduction speed.

In the line indicating the braking force in FIG. 11, an imaginary line extending obliquely downward and to the right from the portion of “braking pedal depressed and released” indicates a case where the braking force is not maintained. In this case, the braking force is reduced without delaying the release of the depression of the brake pedal BP, so that it is not easy to start uphill. This virtual line also indicates the return status of the brake pedal BP.

[Control time chart (2), see FIG. 12] The control time chart (2) also shows a case where the holding brake force when the vehicle is stopped is large (corresponding to a steep slope, braking force 1) and a medium case. (Corresponding to a middle slope, braking force 2) and small (corresponding to a flat road, braking force 3). A thick line in FIG. 12 indicates the driving force, and a thin line indicates the braking force.

The vehicle in the control time chart (2) automatically stops the engine 1 when the vehicle stops. The position switch PSW and the mode switch MSW of the vehicle are not changed in the D mode D range.

Until the vehicle stops, it is the same as the control time chart (1), and the description is omitted. When the vehicle stops (vehicle speed 0 km / h), the braking force holding device RU sets the proportional solenoid valve LSV to the shut-off position and holds the braking force. When the vehicle stops, the driver depresses the brake pedal BP in accordance with the gradient of the stop location, so that the holding brake force at the time of stopping the vehicle also corresponds to the gradient. That is, the holding brake force is large on a steep slope (braking force 1), the holding braking force is medium on a middle slope (braking force 2), and the holding braking force is small on a flat road (braking force 3). At the same time, the engine stop device automatically stops the engine 1 for the purpose of improving fuel efficiency. Therefore, the driving force becomes zero.

Next, the driver releases the brake pedal BP in preparation for the restart. Then, the brake switch BSW is turned off, and an engine automatic start command (F_ENGON) is issued. Then, after a time lag due to a delay in the signal communication system and the mechanical system, the engine 1 is automatically started to start supplying pressure oil to the starting clutch of the CVT 3 (SC [ON]), and the driving force increases. This "S
C (ON) ”activates the creep rise timer,
After a predetermined time has elapsed, it is determined that creep has risen (F_SCDLY), and the release of the holding brake force is started. The significance of the creep rising is as described in the time chart (1). In addition, judging the rise of creep by the creep rise timer is because
This is because when the engine 1 stops, the hydraulic oil in the hydraulic chamber of the starting clutch escapes, so that the hydraulic command value for the starting clutch does not match the actual oil pressure value (driving force transmission capacity). Incidentally, when the vehicle stops while maintaining the weak creep state, the hydraulic command value for the starting clutch and the actual hydraulic value (driving force transmission capacity) match.

As in the control time chart (1), the release of the holding brake force is performed based on the predetermined release time and the holding brake fluid pressure value at the time of creep rise, by the control unit C.
U is the holding brake force (holding brake fluid pressure value)
Is calculated by calculating the target reduction speed according to the target reduction speed, and reducing the current value of the control current supplied to the proportional solenoid valve LSV according to the target reduction speed. In this case, as in the case of the control time chart (1), the control current is adjusted at the time when the release of the holding brake force is started. The magnitude of the target reduction speed is also in the order of braking force 1> braking force 2> braking force 3 as in the case of the control time chart (1), and the braking force 3 (flat road) has the smallest target reduction speed. In each case, the braking force decreases linearly.

Then, when the driving force increases and a strong creep state (F_SCRPON) occurs, a sufficient driving force is generated. For this reason, in the present embodiment, regardless of the magnitude of the holding brake force, before and after the strong creep state (F_
The release time is set so that the current value of the control current supplied to the proportional solenoid valve LSV becomes zero (near SCRPON) and the holding brake force is released. Thereafter, the driving force increases due to depression of the accelerator pedal, and the vehicle accelerates.

In the line indicating the braking force in FIG. 12, an imaginary line extending obliquely downward and to the right from the portion of “braking pedal depressed and released” indicates a case where the braking force is not maintained. In this case, the braking force is reduced without delaying the release of the depression of the brake pedal BP, so that it is not easy to start uphill. This virtual line also indicates the return status of the brake pedal BP.

As described above, the present invention is not limited to the above-described embodiments of the present invention, but may be embodied in various forms. For example, the braking force holding device is constituted by means acting on the brake fluid pressure as means acting on the braking force, but is not particularly limited as long as it can act on the braking force. The release pattern of the holding brake force may not be a linear reduction pattern, but may be a curvilinear reduction pattern as long as the stability during starting operation is not impaired.

[0161]

According to the invention described above, the time from when the starting operation is performed and the reduction of the braking force is started until the application of the braking force is stopped is controlled to be constant.
The time from when the driver performs the start operation to when he / she senses the initial movement of the vehicle is always constant, and the sense of stability at the time of the start operation is improved.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of a vehicle on which a braking force holding device according to an embodiment is mounted.

FIG. 2 is a configuration diagram of a braking force holding device according to the present embodiment.

FIG. 3A is a control logic for holding the braking force, and FIG. 3B is a control logic for permitting the operation of the braking force holding device.

4 (a) is a control logic for setting a weak creep state, FIG. 4 (b) is a control logic for setting a strong creep state during running, and FIG. 4 (c) is a medium creep state of the driving force control apparatus according to the present embodiment. Control logic.

FIG. 5 is a control logic for automatically stopping the engine of the prime mover stopping device according to the present embodiment.

FIG. 6A is a control logic for releasing the holding of the braking force, in the braking force holding device according to the present embodiment;
(B) is a control logic for judging the rise of creep.

7 (a) is a control logic for setting a strong creep state (vehicle reversal detection version), and FIG. 7 (b) is a control logic for setting a strong creep state (vehicle movement detection version). It is.

8A and 8B show an example of a vehicle backward detection method according to the present embodiment, wherein FIG. 8A is a configuration diagram of vehicle backward detection, FIG. 8B is a pulse phase of directional rotation in FIG. a) The pulse phase of the direction rotation in the figure.

9A is a control logic (vehicle reverse detection version) for automatically starting the engine, and FIG. 9B is a control logic (vehicle movement detection version) for automatically starting the engine. is there.

FIG. 10 is a control flowchart of the braking force holding device according to the present embodiment.

FIG. 11 is a control time chart in the case where the engine of a vehicle having the brake force holding device according to the present embodiment is not stopped.

FIG. 12 is a control time chart when the engine of a vehicle on which the braking force holding device according to the present embodiment is mounted is stopped.

[Explanation of symbols]

 RU brake force holding device BP brake pedal

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Toshiya Kanda 1-4-1 Chuo, Wako-shi, Saitama Pref. Honda Technology Laboratory Co., Ltd. (72) Inventor Takahiro Eguchi 1-4-1 Chuo, Wako-shi, Saitama F-term in Honda R & D Co., Ltd. (Reference) 3D046 BB02 CC02 EE01 HH02 HH05 HH06 JJ14 JJ21 KK11 LL23

Claims (1)

[Claims] When the brake pedal is released when the vehicle is stopped, the brake force is maintained so that the brake force corresponding to the depression force of the brake pedal before the depression is released continues to act on the vehicle. This is a brake force holding device that releases the holding of the braking force when an operation is performed.When releasing the holding of the braking force, it holds the time from the start of the reduction of the braking force until the braking force stops working. A brake force holding device characterized by constant control regardless of the magnitude of the braking force that has been applied.