JP6477227B2 - Vehicle control device - Google Patents

Description

  The present invention relates to a vehicle control device.

  Patent Document 1 discloses a technique for preventing engine stall due to deceleration by releasing a friction clutch interposed between an engine and a drive wheel during collision avoidance control.

JP 2014-121886

However, in the above prior art, when the collision avoidance control is no longer necessary due to the movement of the obstacle, or when the driver intentionally continues the acceleration operation with confidence in the safe state, It does not consider how to control the clutch state.
The objective of this invention is providing the control apparatus of the vehicle which can perform control according to a driver | operator's intention after the start of collision avoidance control.

  In the present invention, after the collision avoidance control is started, when the collision avoidance control becomes unnecessary along with the movement of the obstacle, the automatic brake is released and the friction clutch is engaged, while the automatic brake is released and the friction clutch is released. The engine output will continue to be limited even after the conclusion.

  Therefore, after the start of the collision avoidance control, control according to the driver's intention can be performed.

It is a block diagram of the power train of FF hybrid vehicle of Example 1. FIG. It is a control block diagram of HCM20. It is a flowchart which shows the flow of each control after a collision avoidance control action. It is a time chart of the collision avoidance control and engine stall prevention control of a comparative example. 3 is a time chart of collision avoidance control and engine stall prevention control according to the first embodiment.

[Example 1]
[Power train]
FIG. 1 is a configuration diagram of a power train of the FF hybrid vehicle according to the first embodiment.
The engine 1 is a horizontally placed engine disposed in the front room with the rotation axis direction of the crankshaft 1a as the vehicle width direction. The starter motor 2 meshes with an engine start gear 1b provided on the crankshaft 1a. The starter motor 2 uses a 12V battery (not shown) as a power source. The 12V battery is charged by the starter motor 2 functioning as a generator while the engine 1 is operating. Further, the 12V battery is charged with electric power supplied from a lithium ion battery (not shown) via a DC / DC converter (not shown).

  The motor generator 3 has one of its motor output shafts 3 a connected to the engine 1 via a first clutch 4 and the other connected to a belt-type continuously variable transmission 6 via a second clutch 5. . The motor generator 3 is a three-phase AC permanent magnet type synchronous motor, and uses a lithium ion battery as a power source. An inverter 7 is connected to the stator coil of the motor generator 3. The inverter 7 converts the DC power from the lithium ion battery into three-phase AC power and supplies it to the motor generator 3 when the motor generator 3 is powered. Further, when the motor generator 3 is regenerated, the inverter 7 converts the reference AC power generated by the motor generator 3 into DC power and charges the lithium ion battery.

  The first clutch 4 is a normally closed dry single-plate friction clutch capable of continuously changing the engagement capacity in accordance with the supplied hydraulic pressure. The first clutch 4 is provided in the housing of the motor generator 3. The second clutch 5 uses a forward clutch 5a and a reverse brake 5b provided in a forward / reverse switching mechanism of the belt type continuously variable transmission 6 using a planetary gear. The forward clutch 5a and the reverse brake 5b are both normally open wet single-plate friction clutches capable of continuously changing the engagement capacity in accordance with the supplied hydraulic pressure. In the following description, the forward clutch 5a and the reverse brake 5b are collectively referred to as the second clutch 5 unless otherwise described. The belt type continuously variable transmission 6 is a transmission that obtains a continuously variable transmission ratio by changing the winding diameter of the belt 6c in accordance with the hydraulic pressure supplied to the cylinder chambers of the primary pulley 6a and the secondary pulley 6b. An output shaft 6d of the belt-type continuously variable transmission 6 is connected to left and right front wheels 10 which are drive wheels via a final reduction gear train 8, a differential gear (not shown), and left and right drive shafts 9.

  The main oil pump 11 sucks up and pressurizes oil stored in the oil pan 12, and discharges it to the oil passage 13a. The main oil pump 11 is rotationally driven by the motor output shaft 3a. The oil discharged to the oil passage 13a passes through the flapper valve 14a, and after being adjusted as the operating oil pressure by the proportional solenoids 15a, 15b, 15, 15d, 15e, the forward clutches of the first clutch 4 and the second clutch 5 5a, the reverse brake 5b of the second clutch 5, the primary pulley 6a and the secondary pulley 6b are respectively supplied. The flapper valve 14a is a one-way valve that opens when the pressure is equal to or higher than a predetermined pressure.

  The sub oil pump 16 sucks up and pressurizes the oil stored in the oil pan 12, and discharges it to the oil passage 13b. The sub oil pump 16 is driven to rotate by an electric motor using a lithium ion battery as a power source. The oil discharged to the oil passage 13b is supplied to one of the oil passage 13c and the oil passage 13d by the switching valve 17. The switching valve 17 communicates the oil passage 13b and the oil passage 13c when not energized, and communicates the oil passage 13b and the oil passage 13d when energized. The oil supplied to the oil passage 13c passes through the flapper valve 14b, and after being adjusted as the operating oil pressure by the proportional solenoids 15a, 15b, 15, 15d, 15e, the forward clutches of the first clutch 4 and the second clutch 5 5a, the reverse brake 5b of the second clutch 5, the primary pulley 6a and the secondary pulley 6b are respectively supplied. The flapper valve 14b is a one-way valve that opens when the pressure is equal to or higher than a predetermined pressure. The oil supplied to the oil passage 13d is supplied only to the forward clutch 5a of the second clutch 5 as it is as the operating hydraulic pressure. The switching valve 17 is for energizing the forward clutch 5a and is energized when the vehicle stops with the D range selected.

[Driving mode]
The 1-motor, 2-clutch powertrain has three travel modes, namely, “EV travel mode”, “HEV travel mode”, and “WSC travel mode”.
In the EV travel mode, the first clutch 4 is released, the second clutch 5 is engaged, and the motor generator 3 is used as the drive source. “Fastening” means a complete fastening state that does not allow differential rotation between input and output. The motor generator 3 performs torque control based on the target motor torque, and the target motor torque is set according to the required drive torque determined from the accelerator opening, the vehicle speed, and the like.
The HEV travel mode travels while the first clutch 4 and the second clutch 5 are engaged and the engine 1 is included in the drive source. The target engine torque is an engine torque that obtains an operating point where the output efficiency of the engine 1 is high. The motor generator 3 performs torque control based on the target motor torque, and the target motor torque is a difference between the required drive torque and the target engine torque.

In the WSC travel mode, the first clutch 4 is engaged and the second clutch 5 is slipped to travel using only the motor generator 3 as a drive source. Note that “slip” means a slip fastening state that allows differential rotation between input and output. The target second clutch engagement capacity is set according to the required drive torque. The motor generator 3 controls the rotational speed based on the target motor rotational speed, and the target motor rotational speed is set to the idle rotational speed of the engine 1. When starting from a stop in the HEV mode, the difference in rotation between the engine 1 and the front wheels 10 can be absorbed by selecting the WSC travel mode.
The travel mode is selected based on the accelerator opening, the vehicle speed, and the battery SOC in the EV travel mode, HEV travel mode, and WSC travel mode. When the accelerator opening is equal to or smaller than the predetermined opening, the EV mode is selected. When the accelerator opening exceeds the predetermined opening, the WSC mode is selected in the low vehicle speed range, and the HEV mode is selected in the medium / high vehicle speed range. Note that the WSC mode is selected when the battery SOC is low even when the accelerator opening is equal to or less than the predetermined opening.

[Powertrain control system]
The FF hybrid vehicle of the first embodiment has a hybrid control module (HCM) 20, an engine control module (ECM) 21, a motor controller (MC) 22, a CVT control unit (CVTCU) 23 lithium-ion battery controller as powertrain control means. (LBC) 24 and brake control unit (BCU) 25. These are connected via a CAN communication line.
HCM20 is responsible for managing the energy consumption of the entire vehicle and driving the vehicle with maximum efficiency. The HCM 20 includes an engine speed detected by the engine speed sensor 31, a motor speed detected by the motor speed sensor 32, a transmission input speed detected by the transmission input speed sensor 33, and a primary hydraulic sensor 34. Primary pressure detected by the secondary hydraulic pressure sensor 35, secondary pressure detected by the secondary hydraulic pressure sensor 35, forward clutch hydraulic pressure detected by the second clutch hydraulic pressure sensor 36 (second clutch hydraulic pressure), oil temperature detected by the oil temperature sensor 37, accelerator Accelerator opening detected by opening sensor 38, brake pedal stroke detected by brake pedal stroke sensor 39, battery SOC, battery temperature detected by battery temperature sensor 40, and each wheel detected by wheel speed sensor 41 The vehicle speed calculated from the speed is input directly or via CAN communication. The HCM20 determines the powertrain operating point based on each input information, selects the travel mode, and sets each target value (target engine torque, target motor torque, or target motor rotation) according to the travel mode and the state of the lithium ion battery. Number, target first clutch engagement capacity, target second clutch engagement capacity, target gear ratio, target deceleration, etc.).

  The ECM 21 outputs a command for controlling the engine operating point to the throttle valve actuator of the engine 1 based on the target engine torque or the like. MC 22 outputs a command for controlling the motor operating point to inverter 7 based on the target motor torque (or target motor rotation speed). The CVTCU 23 outputs a command to control each engagement capacity of the first clutch 4 and the second clutch 5 to each proportional solenoid 15a, 15b, 15c based on the target first clutch engagement capacity and the target second clutch engagement capacity. The CVTCU 23 outputs a command for controlling the belt winding diameters of the primary pulley 6a and the secondary pulley 6b to the proportional solenoids 15d and 15e based on the target gear ratio. The BCU 25 outputs, to the hydraulic pressure control unit (HU) 26, a command for controlling the friction braking torque generated by the disc brake provided on each wheel based on the target deceleration. Further, when the motor generator 3 is regenerating, the BCU 25 outputs a command for compensating for the shortage with the friction braking torque to the HU 26 if the regenerative braking torque alone cannot be achieved (regenerative cooperative control). The HU 26 supplies brake fluid to the hydraulic caliper of each disc brake based on a command from the BCU 25.

[Collision avoidance control]
FIG. 2 is a control block diagram of the HCM 20.
The laser radar 42 is provided at each of the front end portion and the rear end portion of the vehicle. The laser radar 42 emits laser light in the traveling direction of the vehicle, receives reflected light from an obstacle, and determines the time of laser emission and the light receiving time of the reflected light. By detecting the time difference, the state (relative position, relative speed, etc.) of the obstacle present in the traveling direction of the host vehicle is measured. The camera 43 captures the area around the vehicle. The image processing device 44 calculates the state of the obstacle present in the surrounding environment of the host vehicle and the traveling direction of the host vehicle from the captured image of the camera 43.

The HCM 20 includes a collision avoidance control unit (collision avoidance control means) 20a that executes a collision avoidance control for avoiding a collision with an obstacle due to an erroneous depression of the brake pedal and the accelerator pedal. When the collision avoidance control unit 20a detects a strong depression of the accelerator pedal when the distance to the obstacle in the traveling direction of the host vehicle is close, the collision avoidance control unit 20a prompts the driver with a screen display and a warning sound, and simultaneously Suppression of acceleration by opening limit control and braking by automatic brake control are performed. The determination of a stepping error uses a known method based on the accelerator opening and the change speed of the accelerator opening. Collision avoidance control section 20a, the laser radar 42, if the obstacle is detected by the camera 43 and the image processing apparatus 44, the distance between the vehicle and the obstacle predetermined distance L ₁ or less, and the accelerator opening and the change When the speed is greater than or equal to threshold values APO ₁ and ΔAPO ₁ , accelerator opening limit control and automatic brake control are started.

The accelerator opening restriction control is a control that restricts the value of the accelerator opening for calculating the required drive torque to be smaller than the accelerator opening detected by the accelerator opening sensor 38. When the distance between the vehicle and the obstacle is between L ₁ and L ₂ (<L ₁ ), the collision avoidance control unit 20a makes a request to increase the limit amount of the accelerator opening as the distance is shorter. If the distance between the vehicle and the obstacle is L ₂ or less, a request to make the accelerator opening zero is output to the ECM 21. Collision avoidance control section 20a, the distance between the vehicle and the obstacle when it exceeds L _1, when the vehicle has stopped, or the vehicle speed of the host vehicle has reached a predetermined vehicle speed V ₂ (10~12km / h) When the accelerator opening limit control is canceled.
The automatic brake control is a control for automatically applying a friction braking torque to each wheel regardless of the driver's braking operation. The collision avoidance control unit 20a outputs to the BCU 25 a request to decelerate at a constant deceleration (for example, 0.2G) until the vehicle speed of the host vehicle reaches a target vehicle speed (for example, 5 to 10 km / h) that is about the creep vehicle speed. The target vehicle speed may be set to a lower value as the distance between the own vehicle and the obstacle at the start of the automatic brake control is shorter. The collision avoidance control unit 20a releases the automatic brake control when the vehicle speed drops to the target vehicle speed, but the distance between the vehicle and the obstacle becomes L ₃ (<L ₂ ) or less after the release or during the control. In this case, the vehicle is suddenly decelerated at a constant deceleration (eg, 0.6G) until the host vehicle stops.

[End prevention control]
Since the first clutch 4 is engaged in the HEV traveling mode, if the collision avoidance control is activated during traveling in the HEV traveling mode, if the second clutch 5 is engaged, along with deceleration by the automatic brake control, An engine stall occurs. Therefore, in the first embodiment, engine stall prevention control for preventing engine stall during the collision avoidance control operation is executed. The HCM 20 includes an engine stall prevention control unit (engine stall prevention control means) 20b that executes engine stall prevention control. When the vehicle speed decreases and the possibility of engine stall increases after the start of the collision avoidance control operation, the engine stall prevention control unit 20b outputs a request to switch the second clutch 5 from the engaged state to the slip state to the CVTCU 23.

FIG. 3 is a flowchart showing the flow of each control after the collision avoidance control operation.
In step S1, the engine stall prevention control unit 20b determines whether or not the collision avoidance control is activated. When the collision avoidance control is operating, the braking force is applied to the vehicle by automatic braking, and the engine output is limited by decreasing the accelerator pedal opening. If the determination in this step is YES, the process proceeds to step S2, and if NO, the process proceeds to return.
In step S2, the engine stall prevention control unit 20b determines whether the vehicle speed is equal to or lower than a predetermined vehicle speed V ₁ (30 km / h). If yes, go to step S3, if no, go to return. The predetermined vehicle speed V ₁ is a vehicle speed at which the possibility of engine stall increases due to sudden deceleration.
In step S3, slip control that causes the second clutch 5 to slip is performed in the engine stall prevention control unit 20b. In the present embodiment, the second clutch 5 is controlled to slip, but may be controlled to be completely released.
In step S4, it is determined whether or not the automatic brake control is stopped under the control of the engine stall prevention control unit 20b. The automatic brake release unit (automatic brake release means) 20c of the HCM 20 stops the automatic brake control when the obstacle is moved away from the front of the vehicle and safety is confirmed, although the accelerator pedal is continuously depressed. If YES, the process proceeds to step S5. If NO, the process proceeds to step S7.

In step S5, it determines the HCM engine stall prevention control section 20b, the vehicle speed whether a predetermined vehicle speed V ₂ or more. If YES, the process proceeds to step S6. If NO, the process proceeds to step S7. Predetermined vehicle speed V ₂ is a general engine car lockup vehicle speed equipped with a belt-type continuously variable transmission (e.g., 10~12km / h).
In step S6, the slip control of the second clutch 5 is released in the friction clutch fastening portion (friction clutch fastening means) 20d of the HCM 20. That is, the second clutch 5 is switched from the slip state to the fully engaged state. The completely engaged state referred to here means that the engaged state does not slip with the engine torque applied so far. For example, in step S9, which will be described later, the engagement may be performed with an engagement force that does not cause the clutch to slip with the engine torque immediately before stopping the accelerator opening restriction control.
In step S7, the engine stall prevention control unit 20b continues the slip control of the second clutch 5. Note that, as described above, when the second clutch 5 is completely released in step S3, switching from complete release to slip control is performed in step S7.
In step S8, the collision avoidance control unit 20a determines whether or not the vehicle speed is equal to or higher than a predetermined vehicle speed V ₃ (> V ₁ ). If yes, go to step S9, if no, go to return. Predetermined vehicle speed V ₃ is, for example, 40 km / h.
In step S9, the collision avoidance control unit 20a stops the accelerator opening restriction control and cancels the collision avoidance control.

[Second clutch overheat suppression]
As a comparative example of the first embodiment, an operation when the engine stall prevention control is continued until the collision avoidance control is stopped will be described. FIG. 4 is a time chart of the collision avoidance control and engine stall prevention control of the comparative example.
At time t1, the driver starts depressing the accelerator pedal. Since the vehicle starts according to the accelerator opening, the host vehicle accelerates according to the accelerator pedal opening, and the vehicle speed increases.
At time t2, since it is determined that there is an obstacle in front of the vehicle and the distance between the host vehicle and the obstacle is L ₁ or less, collision avoidance control and engine stall prevention control are started. The accelerator operation becomes invalid (accelerator opening≈0) by the accelerator opening restriction control, and the friction braking torque is applied to each wheel by the automatic brake control, so that the host vehicle decelerates at a constant deceleration. At this time, since the second clutch is switched from the engaged state to the slip state by the engine stall prevention control, the engine 1 maintains the idling rotation and no engine stall occurs.

At time t3, for example, when the obstacle passes in front of the vehicle and no obstacle exists, the automatic brake control stops. However, if all collision avoidance control is canceled, there is a possibility of sudden start. Therefore, the accelerator opening restriction control and the engine stall prevention control are continued, and the amount of restriction on the accelerator opening in the accelerator opening restriction control is gradually reduced. Since the clutch slip state is also maintained, the vehicle speed gradually increases.
At time t4, the distance between the vehicle and the obstacle due to exceeded L _1, accelerator position limit control is stopped, the collision avoidance control and the engine stall prevention control is canceled. The limitation on the accelerator opening is lost, and the second clutch is switched from the slip state to the engaged state.
In such a case, there arises a problem that the slip state of the second clutch continues and the second clutch overheats.

FIG. 5 is a time chart of collision avoidance control and engine stall prevention control according to the first embodiment. The section from time t1 to t3 is the same as the section from t1 to t3 in FIG.
At time t4, since the vehicle speed of the host vehicle has reached the predetermined vehicle speed V ₂ (10 to 12 km / h), the engine stall prevention control is canceled and the second clutch 5 is switched from the slip state to the engaged state.
At time t5, since the vehicle speed of the host vehicle has reached the predetermined vehicle speed V ₃ (40 km / h), the accelerator opening limit control is stopped and the collision avoidance control is released.

  The state in which the automatic brake control is stopped and the accelerator opening restriction control is continued is a state in which the host vehicle is sufficiently decelerated and the acceleration of the vehicle is restricted. Further, even when the accelerator pedal is depressed, the accelerator pedal is gradually increased, so that sudden acceleration of the vehicle can be prevented. Then, by fastening the second clutch 5 at time t4, the slip time of the second clutch 5 can be shortened while ensuring safety. Thereby, even if the driver maintains the intention to accelerate as the obstacle moves, the vehicle can smoothly shift to normal driving. Furthermore, overheating of the second clutch 5 can be suppressed at this time.

  In the first embodiment, the second clutch 5 is engaged after the vehicle speed of the host vehicle increases to a predetermined vehicle speed V2 (10 to 12 km / h), not immediately after the automatic brake control is stopped. This is because if the second clutch 5 is engaged in a state where the vehicle speed is low, the engine speed is suddenly reduced and engine stall is likely to occur. This is because, when the second clutch 5 is locked and engaged after waiting for the vehicle speed information, the engine speed is rapidly reduced and the engine stall is likely to occur when the second clutch 5 is engaged. By waiting for the vehicle speed to rise and engaging the second clutch 5, engine stall can be suppressed.

In the first embodiment, the collision avoidance control is canceled when the vehicle speed of the host vehicle reaches a predetermined vehicle speed V ₃ (40 km / h). In the conventional collision avoidance control, the collision avoidance control is canceled based on the distance between the vehicle and the obstacle, so the vehicle collides with the preceding vehicle (obstacle) in a traffic jam. When the avoidance control is activated, the state in which the acceleration performance is lowered continues, resulting in deterioration of drivability. In contrast, in Example 1, by the vehicle speed of the own vehicle is to release a collision avoidance control when it reaches a predetermined vehicle speed V _3, can be suppressed drivability deterioration when the vehicle continues to travel.

Example 1 has the following effects.
(1) A collision avoidance control unit 20a that applies automatic braking and restricts engine output against the acceleration operation by the driver for collision avoidance, and torque transmission between the engine 1 and the front wheels 10 during the collision avoidance control. In the vehicle control device having the engine stop control unit 20b for slip-engaging or releasing the second clutch 5 for connecting and disconnecting the vehicle, when the collision avoidance is unnecessary during the acceleration operation by the driver, the automatic braking is performed. An automatic brake releasing part 20c for releasing and a friction clutch engaging part 20d for engaging the second clutch 5 after releasing the dynamic brake are provided, and the engine output is continuously limited even after the automatic brake is released and the second clutch 5 is engaged. To do.
Therefore, it is possible to suppress deterioration in drivability when the driver's intention to accelerate is maintained while ensuring safety, and to suppress overheating of the second clutch 5.

(2) After the automatic brake is released, the engine output is increased in a direction approaching the engine output according to the driver's acceleration operation. When the engine output is increased, at least the second clutch 5 is slip-engaged.
Therefore, it is possible to bring the engine output closer to the driver's acceleration intention while suppressing the engine stall.

(3) The friction clutch engaging portion 20d fully engages the second clutch 5 when the vehicle speed of the host vehicle reaches a predetermined first vehicle speed (predetermined vehicle speed V ₂ ).
Therefore, engine stall when the second clutch 5 is completely engaged can be suppressed.

(4) When the predetermined second vehicle speed (predetermined vehicle speed V ₃ ) higher than the first vehicle speed is reached, the engine output restriction is released, and the engine output according to the driver's acceleration request is set.
Therefore, an engine output corresponding to the driver's intention to accelerate can be obtained.

(Other examples)
As mentioned above, although the form for implementing this invention was demonstrated based on the Example, the concrete structure of this invention is not limited to an Example, The design change of the range which does not deviate from the summary of invention And the like are included in the present invention.
The present invention is not limited to the FF hybrid vehicle shown in the first embodiment, but can be applied to a vehicle (engine vehicle, FR hybrid vehicle, 4WD hybrid vehicle) using an engine as a drive source, and the same effects as those of the first embodiment. Play.

1 engine
3 Motor generator
4 First clutch
5 Second clutch
5a Forward clutch (friction clutch)
5b Reverse brake (friction clutch)
6 Belt type continuously variable transmission
7 Inverter
10 Front wheel (drive wheel)
20a Collision avoidance control unit (collision avoidance control means)
20b Engine stall prevention control unit (engine stall prevention control means)
20c Automatic brake release part (automatic brake release means)
20d Friction clutch fastening part (friction clutch fastening means)

Claims (3)

Collision avoidance control means for applying automatic brake and limiting engine output against the acceleration operation by the driver for collision avoidance,
An engine stall prevention control means for slip-engaging or releasing a friction clutch for connecting and disconnecting torque transmission between the engine and the drive wheel during the collision avoidance control;
In a vehicle control device comprising:
Automatic brake release means for releasing the automatic brake when collision avoidance is no longer necessary during the acceleration operation by the driver;
Friction clutch fastening means for fastening the friction clutch after releasing the automatic brake;
With
The collision avoidance control means increases the engine output in a direction approaching the engine output according to the acceleration operation of the driver after the automatic brake is released, and limits the engine output even after the automatic brake is released and the friction clutch is engaged. to continue,
The vehicle engine control apparatus according to claim 1, wherein the engine stall prevention control means slip-engages at least the friction clutch when the collision avoidance control means increases the engine output after the automatic brake is released . The vehicle control device according to claim 1,
The vehicle control apparatus according to claim 1, wherein the friction clutch engaging means completely engages the friction clutch when the vehicle speed of the host vehicle reaches a predetermined first vehicle speed. The vehicle control device according to claim 2,
The collision avoidance control means cancels the engine output restriction when a predetermined second vehicle speed higher than the first vehicle speed is reached, and sets the engine output according to the driver's acceleration request. Control device.

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