JP5485581B2 - Vehicle control device - Google Patents

Description

  The present invention relates to a vehicle control device that cooperatively controls an engine and an electric parking brake.

  An electric parking brake provided in a vehicle such as an automobile drives a mechanical brake that prevents movement when the vehicle is parked or stopped by an electric actuator. Such an electric parking brake, for example, automatically brakes when the vehicle stops on a slope to prevent the vehicle from moving, and for example, the driver's re-start operation based on an increase in engine speed or the like. It is known that when it is detected, it is automatically canceled.

  As a prior art related to such an electric parking brake, for example, in Patent Document 1, in order to automatically release the electric parking brake from a slope or the like to start smoothly, the inclination angle of the road surface on which the vehicle is stopped is measured by an inclination sensor. An electric parking brake control device that detects and releases the parking brake when the electric motor is activated and the value corresponding to the inclination angle increases according to the depression of the accelerator pedal. Is described.

JP 2006-306300 A

However, in the conventional technology as described above, for example, when the driver depresses the accelerator pedal and then returns the accelerator pedal due to some misoperation, the engine speed does not reach a predetermined value, so Even though there is an intention to start, the electric parking brake is not released, which gives the driver discomfort.
In view of the above-described problems, an object of the present invention is to provide a vehicle control device that enables a smooth start even when an accelerator pedal is returned by an erroneous operation.

The present invention solves the above-described problems by the following means.
The invention according to claim 1 is a release condition determining means for determining whether or not a release condition for the electric parking brake device is satisfied, an inclination detecting means for detecting an inclination of the road surface on which the vehicle is stopped, Estimated resistance calculating means for calculating an estimated running resistance according to the inclination angle, driving force calculating means for calculating the driving force of the vehicle, and engine output control means for controlling the output of the engine based on the input from the accelerator pedal The engine output control means includes the estimated resistance calculation means that determines whether the release condition of the electric parking brake is satisfied by the release condition determination means and that the driving force calculated by the driving force calculation means is the estimated resistance calculation means. after There was a calculated estimated running resistance than the rotational speed of the engine regardless of the input from the accelerator pedal the electric parking blur A vehicle control apparatus characterized by automatic release of the key to the feedback control of the output of the engine to a predetermined lower limit engine speed above which is set higher than the engine speed is a threshold value to be performed.

The invention of claim 2 is characterized in that the engine output control means sets the lower limit engine speed so as to generate a driving force equal to or greater than the estimated running resistance calculated by the estimated resistance calculating means. 1. The vehicle control device according to 1.
According to a third aspect of the present invention, in the vehicle control according to the first or second aspect, the engine output control means ends the feedback control when the traveling speed of the vehicle exceeds a predetermined value. Device.
According to a fourth aspect of the present invention, the engine output control means delays the engine output change with respect to the operation of the accelerator pedal during execution of the feedback control from a normal time. It is a vehicle control device given in any 1 paragraph to.

According to the present invention, the following effects can be obtained.
(1) After determining that the release condition of the electric parking brake is satisfied and the driving force exceeds the estimated running resistance, the engine speed becomes equal to or higher than a predetermined lower limit engine speed regardless of the input from the accelerator pedal. By feedback control of the engine output, even if the driver subsequently returns the accelerator pedal due to an erroneous operation etc., the engine output will not decrease and the release of the electric parking brake will not be stopped, making the vehicle smoother You can start.
(2) By setting the lower limit engine speed so that a driving force equal to or greater than the estimated running resistance is generated during feedback control of the engine output, the vehicle can be prevented from retreating due to a road surface gradient or the like.
(3) By terminating the feedback control when the traveling speed of the vehicle becomes a predetermined value or more, it is possible to return to normal control at an appropriate timing.
(4) By delaying the engine output change with respect to the operation of the accelerator pedal during execution of the feedback control from the normal time, the accelerator operation at the time of starting that makes the accelerator operation difficult and the vehicle jumps out more easily than the normal time is facilitated. can do.

It is a typical perspective view which shows the mechanical structure of the Example of the vehicle control apparatus to which this invention is applied. It is a block diagram which shows the structure of the vehicle control apparatus of FIG. It is a flowchart which shows the operation | movement at the time of vehicle start of the vehicle control apparatus of FIG. It is a timing chart which shows transition of each parameter at the time of control execution of Drawing 3. It is a figure which shows the accelerator-throttle characteristic in the vehicle control apparatus of FIG. 1, Comprising: A horizontal axis shows an accelerator opening, and a vertical axis | shaft shows a throttle opening.

  The present invention aims to provide a vehicle control device that enables a smooth start even when the accelerator pedal is returned due to an erroneous operation. The problem was solved by performing feedback control so that the number of revolutions was maintained above a predetermined value.

Embodiments of a vehicle control apparatus to which the present invention is applied will be described below.
The vehicle control device performs coordinated control of the electric parking brake device and the engine. The vehicle control device includes a parking brake 10, an actuator unit 20, a battery 30, a parking brake controller 40, an operation switch 50, an engine control unit 60, a vehicle side unit 70, and the like.

  The parking brake 10 is a mechanical (non-hydraulic pressure) braking device that brakes a vehicle wheel to prevent the vehicle from moving when the vehicle is parked or stopped, for example. Each is provided. The parking brake 10 includes a brake drum (not shown) disposed on the inner diameter side of a rotor of a disc brake used as a foot brake (main brake / service brake), and a brake (not shown) that pressurizes and contacts the inner diameter side of the brake drum during braking. This is a so-called drum-in-disk type equipped with a shoe.

The actuator unit 20 drives the shoe of the parking brake 10 and makes a transition between a braking state in which the parking brake 10 generates a braking force and a released state in which the braking force is not substantially generated. The actuator unit 20 includes a parking brake cable 21 and is fixed to, for example, a floor panel portion of the vehicle.
For example, the actuator unit 20 reduces the rotational force of a direct current (DC) motor by a reduction gear train, rotates a lead screw, and pulls or relaxes the parking brake cable 21 by an equalizer screwed to the lead screw. is there.

The parking brake cable 21 is provided between the actuator unit 20 and the left and right parking brakes 10, respectively, and has flexibility so as to be deformed according to a stroke of a rear suspension (not shown). The parking brake cable 21 brings the parking brake 10 into a braking state by being pulled, and releases the parking brake 10 by being relaxed.
Here, the actuator unit 20 has a function of adjusting the braking force of the parking brake 10 in the braking state by adjusting the traction force applied to the parking brake cable 21. The adjustment of the traction force is performed by changing the stroke with which the actuator unit 20 pulls the parking brake cable 21. For this reason, the actuator unit 20 is provided with a stroke sensor (not shown) that detects this stroke.

The battery 30 is a secondary battery that is used as a main power source for a vehicle electrical system, and generates, for example, a DC 12V terminal voltage. The battery 30 includes a plus terminal 31 and a minus terminal 32.
The plus terminal 31 is connected to the parking brake controller 40 via wiring (harness). As shown in FIG. 2, the wiring for supplying electric power from the plus terminal 31 to the parking brake controller 40 is provided with an ignition wiring 31a and a constant connection wiring 31b. The ignition wiring 31a is inserted at its intermediate portion with an ignition relay I that is switched between conducting and shutting off in conjunction with the on / off of the ignition switch, and is energized when the engine that is the driving power source of the vehicle is turned on. The always-connected wiring 31b is always energized regardless of the operation of the ignition switch.
The minus terminal 32 is grounded with respect to the vehicle body.

The parking brake controller 40 is an electric parking brake control device that controls the actuator unit 20 in accordance with an input from the operation switch 50 and changes the braking force of the parking brake 10 by changing the traction force of the parking brake cable 21. ECU 41, relay 42, and G sensor 43 are provided.
The ECU 41 includes a CPU that determines whether or not the parking brake 10 needs to be braked in response to inputs from the operation switch 50, the engine control unit 60, the vehicle-side unit 70, and the like, and sets braking force when braking is necessary. ing. The ECU 41 includes an integrated controller 41a, a stop determination unit 41b, an inclination determination unit 41c, a running resistance estimation unit 41d, a driving force estimation unit 41e, and the like.
The integrated controller 41a comprehensively controls the stop determination unit 41b, the inclination determination unit 41c, the travel resistance estimation unit 41d, the driving force estimation unit 41e, and the like.
The stop determination unit 41b performs a vehicle stop determination process for determining that the vehicle has shifted from the traveling state to the stopped state using an output of a vehicle speed sensor 71 described later.
The inclination determination unit 41c processes the output of the G sensor 43 and performs a known inclination determination process for determining the inclination of the road surface on which the vehicle stops.

The running resistance estimation unit 41d calculates an estimated running resistance R of the vehicle by multiplying a preset default value by a table value read from a table prepared in advance based on the output of the G sensor 43. It is. The estimated running resistance R is a value that increases as the road gradient increases. The running resistance estimation unit 41d functions as an estimated resistance calculation unit according to the present invention.
The driving force estimation unit 41e refers to a map prepared in advance based on the engine operating state such as the engine speed, the intake air amount, and the throttle opening provided from the engine control unit 60. The force F is calculated. The driving force estimation unit 41e functions as a driving force calculation unit according to the present invention.

The relay 42 supplies driving power to the actuator unit 20 in accordance with a control signal output from the ECU 41. The relay 42 shifts the parking brake 10 from the braking state to the released state, and brakes from the released state. In order to make a transition to the state, a function of reversing the polarity of the drive power is provided, and the actuator unit 20 is in a neutral state where conduction with the actuator unit 20 is interrupted except when the actuator unit 20 is driven.
The G sensor 43 includes an acceleration sensor that detects acceleration acting in the front-rear direction of the vehicle, and inputs the output to the ECU 41.

The operation switch 50 is an operation unit for a user such as a driver to input a manual selection operation of the braking state and the release state of the parking brake 10, and is a push button switch mounted on an instrument panel (not shown) of the vehicle, for example. It has. The operation switch 50 transmits the input to the parking brake controller 40, and the parking brake controller 40 supplies driving power to the actuator unit 20 and drives the parking brake 10 accordingly.
In addition, the operation switch 50 can be turned on / off in an auto mode in which the parking brake 10 is automatically set to a braking state when the vehicle is stopped, and then the parking brake 10 is automatically released according to a start operation by the driver. It has become.

The engine control unit 60 controls the vehicle engine and its auxiliary equipment in an integrated manner. In this embodiment, the engine (not shown) is, for example, a 4-stroke gasoline engine, and performs output control by adjusting the amount of intake air using an electric throttle valve.
The engine control unit 60 and a vehicle-side unit 70 described later can communicate with the parking brake controller 40 via an in-vehicle LAN such as a CAN communication system.

An accelerator opening sensor 61, an engine speed sensor 62, an intake air amount sensor 63, a throttle actuator 64, and the like are connected to the engine control unit 60.
The accelerator opening sensor 61 detects the position (accelerator opening) of an accelerator pedal (not shown) where the driver performs a stepping operation in response to an acceleration request.
The engine rotational speed sensor 62 detects the rotational speed of a crankshaft that is an output shaft of the engine.
The intake air amount sensor 63 is an air flow meter that detects the flow rate of air taken in by the engine as combustion air (fresh air).
The throttle actuator 64 drives a throttle valve that adjusts the intake air amount of the engine in accordance with the target throttle opening that is sequentially set by the engine control unit 60. The engine control unit 60 functions as engine output control means in the present invention in cooperation with the throttle actuator 64.

The vehicle-side unit 70 includes, for example, a transmission control unit (TCU) that controls a vehicle transmission (transmission), a vehicle stability control unit that performs vehicle stability control including ABS control, and other electrical components of the vehicle. It is equipped with a vehicle integration unit that controls it centrally.
The vehicle side unit 70 includes a vehicle speed sensor 71, a brake lamp switch (BLS) 72, and the like.
The vehicle speed sensor 71 is provided in, for example, a wheel hub portion, and is used for detecting the traveling speed (vehicle speed) of the vehicle by outputting a vehicle speed pulse signal corresponding to the rotational speed of a tone wheel that rotates with the wheels.
The BLS 72 is provided on a brake pedal (not shown) that is depressed when the driver performs a braking operation using a hydraulic service brake, and is turned on when the brake pedal is depressed, and is turned off in other cases. It is a switch.

The engine control unit 60 and the vehicle side unit 70 sequentially provide the parking brake controller 40 with information such as, for example, engine speed, accelerator opening, transmission shift position, foot brake operation status, vehicle speed, and the like. In the auto mode, the parking brake controller 40 shifts the parking brake 10 from the braking state to the released state when it is determined that the driver has started the vehicle based on these inputs. For example, in this embodiment, the parking brake 10 is released when the engine speed becomes equal to or greater than a predetermined value due to the accelerator operation. At this time, the parking brake controller 40 functions as a release condition determination unit according to the present invention.
On the other hand, the parking brake controller 40 determines that the parking brake 10 needs to be braked when the stop determination of the stop determination unit 41b is established, and determines that the vehicle has shifted from the running state to the stopped state. Driving electric power is supplied to shift the parking brake 10 from the released state to the braking state. The target braking force at this time is set according to the output of the inclination determination unit 41c.

Next, the operation at the time of vehicle start in the vehicle control device described above will be described step by step for each step of the flowchart shown in FIG. The following processing is started from a state where the vehicle is stopped with the engine turned on and the parking brake 10 is in a braking state.
<Step S01: Judgment of vehicle speed>
The ECU 41 determines whether or not the vehicle speed detected based on the output of the vehicle speed sensor 71 is substantially zero. Specifically, if the vehicle speed is equal to or lower than the detection lower limit speed of the vehicle speed sensor 71, the process proceeds to step S02 assuming that the vehicle speed is substantially zero, and otherwise the process proceeds to step S11.

<Step S02: Determination of accelerator opening>
The ECU 41 determines whether or not the current accelerator opening is substantially fully closed based on the output of the accelerator opening sensor 61 provided from the engine control unit 60. When the ECU 41 is not substantially fully closed ( When the accelerator pedal is depressed), the process proceeds to step S03, and when it is substantially fully closed (when the accelerator pedal is not depressed or is depressed, the depression amount is small), step S11 is performed. Proceed to

<Step S03: BLS off determination>
The ECU 41 determines whether or not the output of the BLS 72 provided from the vehicle side unit 70 is off. When the BLS 72 is off, the process proceeds to step S04, and when it is on, the process proceeds to step S11.

<Step S04: Electric parking brake auto mode determination>
Based on the state of the operation switch 50, the ECU 41 determines whether or not the automatic mode of the electric parking brake is on. When the auto mode is on, the process proceeds to step S05, and when it is off, the process proceeds to step S11.

<Step S05: Estimated Running Resistance R Calculation>
The running resistance estimation unit 41d of the ECU 41 calculates the estimated running resistance R of the vehicle as described above.
Thereafter, the process proceeds to step S06.

<Step S06: Estimated Driving Force F Calculation>
The driving force estimation unit 41e of the ECU 41 calculates the estimated driving force F of the vehicle as described above.
Thereafter, the process proceeds to step S07.

<Step S07: Estimated Driving Force, Estimated Travel Resistance Determination>
The ECU 41 compares the estimated driving force F calculated in step S06 with the estimated traveling resistance R. If the estimated driving force F exceeds the estimated traveling resistance R, the ECU 41 determines that the execution condition of the start-time control is satisfied. The process proceeds to S08, and in other cases, the process proceeds to Step S11 on the assumption that the execution condition of the start control is not satisfied.

<Step S08: Electric parking brake release permission>
The ECU 41 sets a flag that permits the parking brake 10 to be released. Thus, the parking brake controller 40 starts energizing the actuator unit 20 when the engine speed becomes a predetermined value or more, and starts the transition of the parking brake 10 from the braking state to the released state.
Thereafter, the process proceeds to step S09.

<Step S09: Execution of engine speed feedback control>
In response to a control signal from the parking brake controller 40, the engine control unit 60 executes feedback control of the engine speed for controlling the throttle actuator 64 so that the engine speed becomes equal to or higher than a predetermined lower limit engine speed D.
Here, the lower limit engine speed D is set so that the estimated driving force F of the vehicle is equal to or greater than the estimated running resistance R, and is set to a higher speed as the road surface gradient increases. Further, the lower limit engine speed D is set higher than the engine speed which is a threshold value at which the parking brake 10 is automatically released in the auto mode.
Then, it progresses to step S10.

<Step S10: Change accelerator-throttle characteristics>
The engine control unit 60 changes the characteristics of the throttle opening according to the accelerator pedal opening. Specifically, the target throttle opening relative to the accelerator pedal opening is made lower than normal (characteristic 2 in FIG. 5), and the change in the throttle opening per unit time when the accelerator pedal opening changes (throttle throttle). The valve opening / closing speed is decreased to increase the delay amount for delaying the throttle opening change with respect to the accelerator opening change.
Thereafter, the series of processing is terminated (returned). Note that the feedback control of the engine speed and the change in the accelerator-throttle characteristic described above are canceled when the vehicle starting operation is completed when the vehicle speed exceeds a predetermined value.

<Step S11: Electric parking brake release prohibited>
The ECU 41 sets a flag for prohibiting the release of the parking brake 10. At this time, the parking brake controller 40 does not energize the actuator unit 20 regardless of the engine speed, and the parking brake 10 is maintained in a braking state.
Thereafter, the process proceeds to step S12.

<Step S12: Cancel Engine Speed Feedback Control>
The engine control unit 60 cancels the feedback control of the engine speed described above.
Thereafter, the process proceeds to step S13.

<Step S13: Return accelerator-throttle characteristics>
The engine control unit 60 restores the characteristic of the throttle opening corresponding to the accelerator pedal opening described above to the normal characteristic (characteristic 1 in FIG. 5). This return is gradually performed so that the characteristics continuously change.
Thereafter, the series of processing is terminated (returned).

According to the embodiment described above, the following effects can be obtained.
(1) After the release of the parking brake 10 is started and the estimated driving force F becomes equal to or higher than the estimated running resistance R, the engine speed becomes equal to or higher than the predetermined lower limit engine speed D regardless of the input from the accelerator pedal. Thus, by performing feedback control of the throttle actuator 64, even if the driver subsequently returns the accelerator pedal due to an erroneous operation or the like, the engine output does not decrease and the release of the parking brake 10 is not stopped, and the vehicle is You can start smoothly.
(2) By setting the lower limit engine speed D so as to generate a driving force equal to or greater than the estimated traveling resistance R during feedback control of the engine speed, it is possible to prevent the vehicle from retreating due to a road surface gradient or the like.
(3) By terminating the feedback control when the vehicle speed exceeds a predetermined value, it is possible to return to normal control at an appropriate timing.
(4) By delaying the throttle opening change with respect to the accelerator pedal operation during the feedback control from the normal time, the accelerator operation at the start is easier and the vehicle is likely to jump out than normal. Can be.

(Modification)
The present invention is not limited to the embodiments described above, and various modifications and changes are possible, and these are also within the technical scope of the present invention.
(1) The configuration of the vehicle control device is not limited to the above-described embodiment, and can be changed as appropriate. For example, a plurality of units in the embodiment may be integrated, and conversely, a function executed in a single unit in the embodiment may be divided into a plurality of units.
(2) In the embodiment, the engine output control is performed by changing the opening of the electric throttle valve, for example. However, the present invention is not limited to this, and for example, the lift amount of the intake valve and the valve opening timing. The present invention can also be applied to an engine having a so-called valve throttle that adjusts the output by changing the valve closing timing, and a diesel engine that adjusts the output by changing the combustion injection amount.
(3) The method for estimating the running resistance and driving force of the vehicle is not limited to the one in the embodiment, and can be changed as appropriate.

DESCRIPTION OF SYMBOLS 10 Parking brake 20 Actuator unit 21 Parking brake cable 30 Battery 31 Positive terminal 31a Ignition wiring 31b Regular connection wiring I Relay 40 Parking brake controller 41 ECU
41a Integrated controller 41b Stop determination unit 41c Inclination determination unit 41d Travel resistance estimation unit 41e Driving force estimation unit 42 Relay 43 G sensor 50 Operation switch 60 Engine control unit 61 Accelerator opening sensor 62 Engine rotation speed sensor 63 Intake air amount sensor 64 Throttle Actuator 70 Vehicle side unit 71 Vehicle speed sensor 72 Brake lamp switch

Claims (4)

Cancellation condition determination means for determining whether the cancellation condition of the electric parking brake device is satisfied;
Inclination detecting means for detecting the inclination of the road surface on which the vehicle is stopped;
An estimated resistance calculating means for calculating an estimated running resistance according to an inclination angle of the road surface;
Driving force calculating means for calculating the driving force of the vehicle;
An engine output control means for controlling the output of the engine based on an input from an accelerator pedal,
The engine output control means determines that the release condition of the electric parking brake is satisfied by the release condition determination means, and the driving force calculated by the driving force calculation means is greater than or equal to the estimated running resistance calculated by the estimated resistance calculation means. After that, regardless of the input from the accelerator pedal , the engine speed becomes equal to or higher than a predetermined lower limit engine speed set higher than the engine speed, which is a threshold value at which the electric parking brake is automatically released. As described above, the vehicle control apparatus performs feedback control on the output of the engine. 2. The vehicle control device according to claim 1, wherein the engine output control unit sets the lower limit engine speed so as to generate a driving force equal to or greater than the estimated running resistance calculated by the estimated resistance calculating unit. . The vehicle control device according to claim 1 or 2, wherein the engine output control means ends the feedback control when a traveling speed of the vehicle becomes a predetermined value or more. The engine output control means delays the engine output change with respect to the operation of the accelerator pedal during execution of the feedback control from the normal time. 4. The vehicle control device described.

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