JP2018019557A - Vehicle control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle control device capable of suppressing excessive increase of a deceleration of a vehicle even when power generation is performed by a power generator.SOLUTION: A target acceleration of a vehicle corresponding to an engine speed and intake pipe pressure is set in order to control power generation by an alternator. Meanwhile, an actual acceleration of a vehicle is acquired. Then, power generation by the alternator is feed-back-controlled so as to allow a deviation between a target acceleration and an actual acceleration to be zero. Thus, an actual acceleration of the vehicle 1 is allowed to coincide with a target acceleration while securing power generation by the alternator. Besides, control gain of feed-back control is set in accordance with brake fluid pressure.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a vehicle control device.

  An alternator is mounted on a vehicle that uses an engine as a drive source. The power of the engine output shaft is transmitted to the alternator, and the power is converted into electric power used by an electric load such as an air conditioner or an audio device by the alternator.

  In recent vehicles, in order to improve fuel efficiency, when the accelerator operation is canceled during driving, the fuel supply to the engine is stopped (fuel cut), and the alternator is controlled to generate power actively. The As a result, the rotation transmitted from the wheels to the output shaft of the engine can be regenerated as electric power during coasting of the vehicle. And by charging the battery with the regenerated electric power, it is possible to suppress the power generation of the alternator by the power generated by the engine, and to improve the fuel consumption.

JP 2016-46878 A

  However, when power is generated by the alternator, the regenerative torque acts on the wheels via the output shaft of the engine, which increases the deceleration of the vehicle, releases the brake operation by the driver, and releases the accelerator operation by the driver. Sometimes done. When these operations are performed, the amount of power generated by the alternator is reduced, and the effect of improving fuel consumption is reduced.

  An object of the present invention is to provide a vehicle control device capable of suppressing an excessive deceleration of a vehicle even when power is generated by a generator.

  In order to achieve the above object, a vehicle control device according to the present invention is a control device used in a vehicle equipped with an engine, a generator that generates electric power by rotating the engine, and a brake that applies a braking force by hydraulic pressure to wheels. The target acceleration setting means for setting the target acceleration according to the engine speed and the intake pipe pressure, the real acceleration acquisition means for acquiring the actual acceleration of the vehicle, and the control gain according to the hydraulic pressure of the brake are set. Feedback of power generation by the generator based on the difference between the target acceleration set by the target acceleration setting means and the actual acceleration acquired by the actual acceleration acquisition means and the control gain set by the gain setting means Control means for controlling.

  According to this configuration, in order to control the power generation by the generator, the target acceleration of the vehicle according to the engine speed and the intake pipe pressure is set. On the other hand, the actual acceleration of the vehicle is acquired. Then, the power generation by the generator is feedback controlled so that the deviation between the target acceleration and the actual acceleration becomes zero. Thereby, the actual acceleration of the vehicle can be matched with the target acceleration while ensuring the power generation by the generator. Therefore, even if the generator generates power when the vehicle is decelerated, it is possible to suppress the deceleration of the vehicle from being excessive, and it is possible to suppress the release of the brake operation or the operation of the accelerator. As a result, the amount of power generated by the generator can be ensured, and fuel consumption can be improved.

  Further, a feedback control gain is set in accordance with the brake hydraulic pressure. For example, when the brake hydraulic pressure is high, the feedback control gain is set small, so that the change in the amount of power generated by the generator can be reduced, and the change in the deceleration of the vehicle due to the change in the regenerative torque can be smoothed. can do. As a result, even if power is generated by the generator with the brake hydraulic pressure being high, it is possible to prevent the deceleration of the vehicle from becoming excessive, and the brake operation can be released or the accelerator operation can be further performed. Can be suppressed.

  ADVANTAGE OF THE INVENTION According to this invention, even if power generation by a generator is performed at the time of deceleration of a vehicle, it can suppress that the deceleration of a vehicle becomes excessive, and it can suppress that brake operation is cancelled | released or accelerator operation is made. . As a result, the amount of power generated by the generator can be ensured, and fuel consumption can be improved.

It is a figure which shows the structure of the principal part of the vehicle by which the control apparatus which concerns on one Embodiment of invention is mounted. It is a block diagram which shows the structure regarding the function which performs feedback control of the electric power generation by an alternator. It is a figure for demonstrating the setting method of the control gain according to brake fluid pressure and engine speed. It is a flowchart which shows the flow of a control gain learning process.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

<Vehicle configuration>
FIG. 1 is a diagram illustrating a configuration of a main part of a vehicle 1 on which a control device according to an embodiment of the present invention is mounted.

  The vehicle 1 is an automobile that uses the engine 2 as a drive source.

  The engine 2 is provided with an electronic throttle valve for adjusting the amount of intake air into the combustion chamber of the engine 2, an injector (fuel injection device) that injects fuel into the intake air, and an ignition plug that generates electric discharge in the combustion chamber. It has been. The engine 2 is provided with a starter 3 for starting the engine 2.

  An alternator 4 is mounted on the vehicle 1. The alternator 4 includes a rotor, a stator, and an IC regulator. The rotor rotates as the crankshaft of the engine 2 rotates. The rotor is provided with a field coil (rotor coil). By supplying a field current (excitation current) from the IC regulator to the field coil of the rotating rotor, a three-phase alternating current by electromagnetic induction flows through the stator coil provided in the stator. The three-phase AC current is rectified to a DC voltage by a rectifier. The alternator 4 outputs DC power as generated power, and the generated power is supplied to the battery 5 to charge the battery 5.

  The IC regulator controls the duty ratio FDUTY of the field current supplied to the field coil. The power generation amount of the alternator 4 increases as the duty ratio FDUTY of the field current increases, and the power generation amount of the alternator 4 decreases as the duty ratio FDUTY decreases.

  The vehicle 1 includes a plurality of ECUs (Electronic Control Units). The plurality of ECUs include an engine ECU 11 and a brake ECU 12. Each ECU has a configuration including a microcomputer (microcontroller unit). The microcomputer includes, for example, a CPU, a ROM, a RAM, a data flash (flash memory), and the like. The plurality of ECUs are connected so as to be capable of bidirectional communication using a CAN (Controller Area Network) communication protocol.

  An engine speed sensor 21 and an intake pipe pressure sensor 22 are connected to the engine ECU 11.

  The engine speed sensor 21 outputs a pulse signal synchronized with the rotation of the engine 2 (rotation of the crankshaft) as a detection signal. The engine ECU 11 converts the frequency of the pulse signal input from the engine speed sensor 21 into the speed of the engine 2 (engine speed).

  The intake pipe pressure sensor 22 outputs a detection signal corresponding to the intake pipe pressure of the engine 2. The engine ECU 11 acquires the intake pipe pressure of the engine 2 from the detection signal input from the intake pipe pressure sensor 22.

  The engine ECU 11 is provided in the engine 2 for starting, stopping and adjusting the output of the engine 2 based on information obtained from detection signals of various sensors and / or various information input from other ECUs. The electronic throttle valve, injector, spark plug, starter 3 and the like are controlled. Further, the engine ECU 11 generates a voltage adjustment signal and outputs the voltage adjustment signal to the IC regulator of the alternator 4. When the voltage adjustment signal is received by the IC regulator, the IC regulator controls the duty ratio FDUTY of the field current of the alternator 4 based on the voltage adjustment signal.

  A brake fluid pressure sensor 23, a vehicle speed sensor 24, a G sensor 25, and the like are connected to the brake ECU 12.

  The brake fluid pressure sensor 23 outputs a detection signal corresponding to the fluid pressure generated by the brake master cylinder 26 (brake fluid pressure). The brake ECU 12 acquires the brake fluid pressure from the detection signal of the brake fluid pressure sensor 23.

  In the brake system of the vehicle 1, when the brake pedal is depressed, the pedaling force input to the brake pedal is transmitted to the brake booster. The pedal effort transmitted to the brake booster is amplified (boosted) by the negative pressure of the brake booster and is input from the brake booster to the brake master cylinder 26. In the brake master cylinder 26, a hydraulic pressure corresponding to the force input from the brake booster is generated. The hydraulic pressure in the brake master cylinder 26 is transmitted to the brake actuator 27. The brake actuator 27 incorporates a valve for controlling the hydraulic pressure of a wheel cylinder provided in the brake of each wheel. The hydraulic pressure transmitted from the brake master cylinder 26 to the brake actuator 27 is distributed and transmitted to the wheel cylinder of each brake. A brake force (braking force) is applied from the brake to the wheel by the hydraulic pressure of the wheel cylinder.

  The vehicle speed sensor 24 includes, for example, a rotor made of a magnetic body that rotates as the vehicle 1 travels, and an electromagnetic pickup that is provided in non-contact with the rotor. Each time the rotor rotates by a certain angle, a pulse signal is output from the electromagnetic pickup, and the pulse signal is input to the brake ECU 12. Since the frequency of the pulse signal corresponds to the vehicle speed, the brake ECU 12 converts the frequency of the pulse signal input from the vehicle speed sensor 24 into the vehicle speed.

  The G sensor 25 employs a sensor that outputs a signal corresponding to the displacement of the weight as a detection signal corresponding to the acceleration of the vehicle 1. When the vehicle speed and / or the road surface gradient change, the weight is displaced, and a signal corresponding to the displacement is output from the G sensor 25. The brake ECU 12 acquires the acceleration (actual G) of the vehicle 1 from the detection signal of the G sensor 25.

  The vehicle speed sensor 24 and the G sensor 25 may be connected to an ECU different from the brake ECU 12. In that case, the vehicle speed and acceleration may be acquired by the ECU, and the vehicle speed and acceleration may be input to the brake ECU 12.

  The brake ECU 12 controls the brake actuator 27 and the like based on the vehicle speed, the operation amount of the brake pedal, and various information input from other ECUs, and the vehicle 1 is kept in a state where the posture of the vehicle 1 is kept stable. The braking force applied to the wheel from each brake is controlled so as to be braked.

<Alternator control function>
FIG. 2 is a block diagram showing a configuration related to a function for feedback control of power generation by the alternator 4. FIG. 3 is a view for explaining a control gain setting method according to the brake fluid pressure and the engine speed.

  The engine ECU 11 substantially includes a target G setting unit 101, a subtracting unit 102, a gain setting unit 103, and an FDUTY setting unit 104 as processing units for performing feedback control of power generation by the alternator 4. These processing units are realized by software by program processing, or a part thereof is realized by hardware such as a logic circuit.

  The target G setting unit 101 sets a target acceleration (target G) of the vehicle 1 according to the engine speed and the intake pipe pressure. Specifically, the non-volatile memory of the engine ECU 11 stores a map indicating the relationship between the engine speed and the intake pipe pressure and the target acceleration. From this map, a target corresponding to the engine speed and the intake pipe pressure is stored. The acceleration is read out.

  The subtraction unit 102 obtains a deviation between the target acceleration set by the target G setting unit 101 and the actual acceleration (actual G) of the vehicle 1.

  The gain setting unit 103 sets a control gain according to the brake fluid pressure and the engine speed. As shown in FIG. 3, the rewritable nonvolatile memory of the engine ECU 11 stores a map indicating the relationship between the brake fluid pressure, the engine speed, and the control gain. In this map, for example, one control gain is associated with the region A where the brake fluid pressure is 0 or more and less than 50 kPa and the engine speed is 0 or more and less than 1500 rpm, and the brake fluid pressure is 0 or more and 50 kPa. And one control gain is associated with the region B where the engine speed is 1500 or more and less than 8000 rpm. Further, one control gain is associated with the region C where the brake fluid pressure is 50 kPa or more and less than 120 kPa and the engine speed is 0 or more and less than 1500 rpm, and the brake fluid pressure is 50 kPa or more and less than 120 kPa, And one control gain is matched with the area | region D whose engine speed is 1500 or more and less than 8000 rpm. The control gain according to the brake fluid pressure and the engine speed is read from the map shown in FIG.

  The FDUTY setting unit 104 multiplies the deviation between the target acceleration obtained by the subtracting unit 102 and the actual acceleration by the control gain set by the gain setting unit 103 to obtain the target value of the duty ratio FDUTY of the field current of the alternator 4. Set. Then, a voltage adjustment signal corresponding to the target value of the duty ratio FDUTY is generated, and the voltage adjustment signal is output to the IC regulator of the alternator 4.

<Control gain learning process>
FIG. 4 is a flowchart showing the flow of the control gain learning process.

  When the control gain is set by the gain setting unit 103, the engine ECU 11 executes a control gain learning process for learning the control gain.

In the control gain learning process, the gain setting unit 103 uses the control gain associated with the same area A to D of the map shown in FIG. 3 as the control gain used by the FDUTY setting unit 104 for a first predetermined time ( For example, it is determined whether or not it is set over 3 seconds (step S1).
From the time when the control gain is set until the first predetermined time elapses, the map shown in FIG. 3 is associated with areas A to D different from the areas A to D with which the control gain is associated. When the control gain is set (NO in step S1), the subsequent processing is not executed.
When the control gain associated with the same areas A to D of the map shown in FIG. 3 is set as the control gain used in the FDUTY setting unit 104 over a first predetermined time (YES in step S1) The deviation (G deviation) between the target deceleration and the actual deceleration calculated by the subtracting unit 102 is -0.1 within a first predetermined time (for example, 3 seconds) from the setting of the control gain by the gain setting unit 103. It is determined whether or not it falls within the range of 0.1 to 0.1 (step S2).

  When the deviation between the target deceleration and the actual deceleration is within the range of −0.1 to 0.1 within the first predetermined time from the setting of the control gain (YES in step S2), the learning correction of the control gain is performed. The control gain learning process is terminated without being performed.

  On the other hand, if the deviation between the target deceleration and the actual deceleration does not fall within the range of −0.1 to 0.1 within the first predetermined time from the setting of the control gain (NO in step S2), It is determined whether or not the deviation between the target deceleration and the actual deceleration is within the range of −0.1 to 0.1 within the second predetermined time (for example, 6 seconds) from the setting of the control gain ( Step S3).

  When the deviation between the target deceleration and the actual deceleration is within the range of −0.1 to 0.1 within the second predetermined time from the setting of the control gain (YES in step S3), the first gain is set to the current gain. A correction value (for example, 0.001) is added or subtracted (step S4). For example, if the average value of the deviation between the target deceleration and the actual deceleration acquired from when the gain is set until the first predetermined time elapses is negative (a negative number), the first correction value is added to the current gain. Are added, and if the average value of the deviation is positive (positive value), the first correction value is subtracted from the current gain.

  Further, in the map showing the relationship between the brake fluid pressure, the engine speed and the control gain, that is, the map shown in FIG. 3, the areas A to D where the gain before addition or subtraction is set are specified. Then, the gain associated with the identified areas A to D is learned and corrected to the gain after the addition (step S5), and the control gain learning process is terminated.

  If the deviation between the target deceleration and the actual deceleration does not fall within the range of -0.1 to 0.1 within the second predetermined time from the setting of the control gain (NO in step S3), the current gain is Two correction values (for example, 0.005) are added or subtracted (step S6). For example, if the average value of the deviation between the target deceleration and the actual deceleration acquired from when the gain is set until the second predetermined time elapses is negative (negative number), the second correction value is added to the current gain. If the average value of the deviation is positive (positive value), the second correction value is subtracted from the current gain.

  Further, areas A to D in which the control gain before addition or subtraction is set are specified in the map showing the relationship between the brake fluid pressure, the engine speed, and the control gain, that is, the map shown in FIG. Then, the gain associated with the identified areas A to D is learned and corrected to the gain after the addition (step S5), and the control gain learning process is terminated.

<Effect>
As described above, in order to control the power generation by the alternator 4, the target acceleration of the vehicle 1 according to the engine speed and the intake pipe pressure is set. On the other hand, the actual acceleration of the vehicle 1 is acquired. The power generation by the alternator 4 is feedback controlled so that the deviation between the target acceleration and the actual acceleration becomes zero. Thereby, the actual acceleration of the vehicle 1 can be matched with the target acceleration while ensuring the power generation by the alternator 4. Therefore, even if the power generation by the alternator 4 is performed when the vehicle 1 is decelerated, it is possible to suppress the deceleration of the vehicle 1 from being excessive, and it is possible to suppress the release of the brake operation or the operation of the accelerator. As a result, the amount of power generated by the alternator 4 can be ensured, and fuel consumption can be improved.

  Further, a control gain of feedback control is set according to the brake fluid pressure. For example, when the brake fluid pressure is large, the control gain of the feedback control is set small, so that the change in the amount of power generated by the alternator 4 can be reduced, and the change in the deceleration of the vehicle 1 due to the change in the regenerative torque can be smoothed. Can be. As a result, even if power generation by the alternator 4 is performed in a state where the brake hydraulic pressure is large, it is possible to suppress the deceleration of the vehicle 1 from being excessive, and the brake operation is released or the accelerator operation is performed. It can be further suppressed.

<Modification>
As mentioned above, although one Embodiment of this invention was described, this invention can also be implemented with another form.

  For example, in the above-described embodiment, the configuration in which the engine ECU 11 and the brake ECU 12 are individually provided is taken up, but part or all of the functions of the engine ECU 11 and the brake ECU 12 may be integrated into one ECU.

  In addition, various design changes can be made to the above-described configuration within the scope of the matters described in the claims.

1 Vehicle 2 Engine 4 Alternator (generator)
11 Engine ECU (control device)
12 Brake ECU (actual acceleration acquisition means)
25 G sensor (actual acceleration acquisition means)
26 Brake master cylinder (brake)
27 Brake actuator (brake)
101 Target G setting section (target acceleration setting means)
102 Subtraction unit (actual acceleration acquisition means)
103 Gain setting section (gain setting means)
104 FDUTY setting section (control means)

Claims (1)

A control device used in a vehicle equipped with an engine, a generator that generates electric power by rotation of the engine, and a brake that applies a braking force by hydraulic pressure to wheels,
Target acceleration setting means for setting a target acceleration according to the engine speed and the intake pipe pressure;
Actual acceleration acquisition means for acquiring the actual acceleration of the vehicle;
A gain setting means for setting a control gain according to the hydraulic pressure of the brake;
Based on the deviation between the target acceleration set by the target acceleration setting means and the actual acceleration acquired by the actual acceleration acquisition means and the control gain set by the gain setting means, feedback control of power generation by the generator is performed. And a vehicle control device.

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