JP5487811B2 - Vehicle power generation control system - Google Patents

Description

  The present invention relates to a power generation control system for a vehicle that can regeneratively generate kinetic energy during deceleration traveling.

  As a power generation system mounted on a vehicle such as an automobile, a generator capable of changing a generated voltage, a high voltage system circuit including a high voltage battery, a low voltage system circuit including a low voltage battery, and a generator are generated. And a switch for supplying the generated electrical energy to either the high voltage system circuit or the low voltage system circuit, and a system for increasing the generated voltage of the generator and supplying it to the high voltage system circuit when braking the vehicle It is known (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 5-161202 Japanese Patent Laid-Open No. 9-261887 Japanese Patent No. 3632319 JP 2006-311632 A Japanese Patent No. 4172094 JP 2004-336887 A JP-A-2005-22562

  By the way, when the generated voltage is switched from a low voltage to a high voltage during braking of the vehicle, the regenerative braking force changes suddenly, and the feeling of deceleration given to the driver changes suddenly. As a result, the drivability of the vehicle may be reduced.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to reduce drivability associated with a change in the generated voltage in a vehicle power generation control system including a generator capable of changing the generated voltage. It is to suppress.

  The present invention employs the following means in order to solve the above-described problems. That is, the present invention relates to a vehicle power generation control system that switches power supply to a low voltage system circuit and power supply to a high voltage system circuit in accordance with the power generation voltage of the alternator. During the transition period when the voltage suitable for one of the system circuits is changed to the voltage suitable for the other, the generated voltage is adjusted according to the acceleration / deceleration required by the driver.

Specifically, the vehicle power generation control system according to the present invention includes:
An alternator that operates using the kinetic energy of the motor or wheels of the vehicle and can change the generated voltage;
A low-voltage circuit connected to the first power storage device;
A high voltage system circuit connected to a second power storage device capable of inputting and outputting a higher voltage than the first power storage device;
A changeover switch for switching a supply destination of electricity generated by the alternator to either the low voltage system circuit or the high voltage system circuit in accordance with the power generation voltage of the alternator;
Detecting means for detecting the acceleration / deceleration required for the vehicle;
In the transition period in which the generated voltage of the alternator is changed from a voltage suitable for one of the low voltage system circuit and the high voltage system circuit to a voltage suitable for the other, the generated voltage of the alternator according to the detection result of the detection means Control means for adjusting,
Is provided.

  When the power generation voltage of the alternator is changed, the amount of kinetic energy consumed (regenerated) by the alternator changes. For this reason, in the vehicle in which the alternator generates power using the kinetic energy of the prime mover or wheels, the acceleration / deceleration rate of the vehicle changes when the power generation voltage of the alternator is changed.

  For example, when the generated voltage of the alternator is changed from a voltage suitable for a low voltage system circuit (hereinafter referred to as “low voltage”) to a voltage suitable for a high voltage system circuit (hereinafter referred to as “high voltage”). The force to decelerate the vehicle increases. For this reason, the degree of deceleration of the vehicle increases or the degree of acceleration of the vehicle decreases. On the other hand, when the power generation voltage of the alternator is changed from a high voltage to a low voltage, the force for decelerating the vehicle becomes small. For this reason, the degree of deceleration of the vehicle becomes low, or the degree of acceleration of the vehicle becomes high.

  Therefore, when the vehicle is in a decelerating state, the alternator power generation voltage can be set to a high voltage, and when the vehicle is in a non-decelerating state (acceleration state or constant speed state), the alternator power generation voltage can be set to a low voltage. preferable.

  However, when the driving state of the vehicle changes from one of the deceleration state or the non-deceleration state to the other, and the power generation voltage of the alternator is changed at one time, the acceleration / deceleration rate of the vehicle changes abruptly, There is a possibility of giving a shock or discomfort to the driver of the vehicle.

  For example, when the power generation voltage of the alternator is abruptly changed when the driver is requesting relatively gentle acceleration / deceleration, the acceleration / deceleration rate of the vehicle changes abruptly. Therefore, the acceleration / deceleration rate requested by the driver of the vehicle (hereinafter referred to as “requested acceleration / deceleration rate”) and the actual acceleration / deceleration rate may be separated from each other, and a driving operation for correcting it may be required. is there. As a result, the drivability of the vehicle may be reduced.

  On the other hand, when the driver requests a relatively rapid acceleration / deceleration, the driver can predict a sudden change in the acceleration / deceleration rate. For this reason, even if the power generation voltage of the alternator is suddenly changed, the difference between the required acceleration / deceleration rate and the actual acceleration / deceleration rate is considered to be small.

  On the other hand, according to the vehicle power generation control system of the present invention, in the transition period in which the power generation voltage of the alternator is changed from either the low voltage or the high voltage to the other, the power generation of the alternator according to the required acceleration / deceleration rate. The voltage will be changed. Therefore, the difference between the required acceleration / deceleration rate and the actual acceleration / deceleration rate can be reduced. As a result, a decrease in drivability is also suppressed.

  For example, the control means of the present invention may lower the change rate of the generated voltage of the alternator when the required acceleration / deceleration rate is low than when it is high. At that time, the control means may change the change speed stepwise with respect to the required acceleration / deceleration rate, or may change the change speed continuously.

  When the change speed of the generated voltage is adjusted in this way, the generated voltage can be changed more gently when the required acceleration / deceleration rate is low than when it is high. As a result, the difference between the required acceleration / deceleration rate and the actual acceleration / deceleration rate is further reduced.

The control means may change the power generation voltage of the alternator at a time when the acceleration / deceleration rate detected by the detection means exceeds a predetermined reference. That is, when the driver requests rapid acceleration / deceleration, the power generation voltage of the alternator may be immediately changed from one of the low voltage and the high voltage to the other. According to such control, the acceleration / deceleration rate of the vehicle can be quickly increased.

  Further, the control means of the present invention temporarily reduces the generated voltage of the alternator to a predetermined voltage set lower than the low voltage before starting the change of the generated voltage of the alternator, and the generated voltage of the alternator is less than the predetermined voltage. At some time, the changeover switch may be switched. The predetermined voltage is a voltage lower than the low voltage and includes zero.

  In this case, since the power generation voltage of the alternator is raised to a low voltage or a high voltage after the power generation voltage of the alternator is once lowered below a predetermined voltage, it is possible to avoid a situation in which the acceleration / deceleration rate of the vehicle changes rapidly. Furthermore, since the changeover switch performs the switching operation when the power generation voltage of the alternator is lowered to a predetermined voltage or lower, it is possible to reduce the load applied to the changeover switch.

  If the acceleration / deceleration detected by the detection means exceeds a predetermined reference, the control means skips the process of temporarily reducing the power generation voltage of the alternator, changes the power generation voltage, and switches the changeover switch. The operation may be started. According to such control, the acceleration / deceleration rate of the vehicle can be quickly increased.

  By the way, when the degree of acceleration requested by the driver is high, the accelerator opening degree becomes larger and the increase speed of the accelerator opening degree becomes higher than when the acceleration degree is low. Also, when the degree of deceleration requested by the driver is high, the gear ratio of the transmission is changed to a low speed side (for example, a downshift operation), or an operation for operating the braking device (for example, a brake) Pedal depression), the amount of operation of the braking device (for example, the amount of depression of the brake pedal) increases, or the operation speed of the braking device (for example, the depression speed of the brake pedal) increases. As described above, at least one of the accelerator opening, the state of the braking device, and the state of the transmission correlates with the acceleration / deceleration required by the driver.

  Therefore, the detection means of the present invention may detect the acceleration / deceleration based on at least one of the accelerator opening, the state of the braking device, and the state of the transmission. In this case, since the required acceleration / deceleration rate can be detected more accurately, the difference between the required acceleration / deceleration rate and the actual acceleration / deceleration rate can be further reduced.

  The control means is configured such that when the operation for operating the braking device is performed during deceleration of the vehicle, the transmission gear ratio is predetermined when the operation amount of the braking device is greater than a predetermined reference operation amount. If the speed ratio is lower than the reference speed ratio, it may be determined that the required deceleration rate exceeds the reference.

  Further, the control means is required for the vehicle when the accelerator opening is larger than a predetermined reference opening or when the acceleration opening increase rate is higher than a predetermined reference speed during acceleration of the vehicle. It may be determined that the acceleration rate exceeds the reference.

  The reference operation amount, the reference opening, and the reference speed described above correspond to the lower limit value of a range in which it is recognized that the driver can sense the difference between the acceleration / deceleration required for the vehicle and the actual acceleration / deceleration. It is determined in advance by an adaptation operation using an experiment or the like.

The control means of the present invention detects the actual acceleration / deceleration rate during and / or after changing the power generation voltage of the alternator, and sets the detected acceleration / deceleration rate so as to match the required acceleration / deceleration rate. The generated voltage may be feedback controlled. In this case, the difference between the required acceleration / deceleration rate and the actual acceleration / deceleration rate can be made extremely small.

  ADVANTAGE OF THE INVENTION According to this invention, the fall of the drivability accompanying the change of a generated voltage can be suppressed in the power generation control system of the vehicle provided with the generator which can change a generated voltage.

It is a figure which shows schematic structure of the vehicle to which this invention is applied. It is a figure which shows schematic structure of an electric power generation mechanism. It is a timing chart which shows the correlation with vehicle speed, the operating state of a changeover switch, and a target generated voltage with time. It is a timing chart which shows the change method of the target electric power generation voltage in a 1st Example. It is a flowchart which shows the electric power generation control routine in a 1st Example. It is a timing chart which shows the change method of the target electric power generation voltage in a 2nd Example. It is a flowchart which shows the electric power generation control routine in a 2nd Example. It is a figure which shows the other structural example of an electric power generation mechanism.

  Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. The dimensions, materials, shapes, relative arrangements, and the like of the components described in the present embodiment are not intended to limit the technical scope of the invention to those unless otherwise specified.

<Example 1>
First, a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a diagram showing a schematic configuration of a vehicle to which the present invention is applied.

  In FIG. 1, the vehicle is equipped with an internal combustion engine 1 as a prime mover. The output shaft of the internal combustion engine 1 is connected to the input shaft of the transmission 2. An output shaft of the transmission 2 is connected to a differential gear 4 via a propeller shaft 3. Two drive shafts 5 are connected to the differential gear 4, and the drive shafts 5 are connected to the left and right drive wheels 6, respectively.

  Examples of the transmission 2 described above include a combination of a torque converter or a clutch mechanism and a speed change mechanism that changes the speed ratio stepwise or steplessly.

  The power (rotational torque of the output shaft) output from the internal combustion engine 1 is transmitted to the propeller shaft 3 after being converted in speed by the transmission 2, and then transmitted to the drive shaft 5 and the drive wheels 6 after being decelerated by the differential gear 4. Is done.

  The internal combustion engine 1 is provided with a power generation mechanism 100. As shown in FIG. 2, the power generation mechanism 100 includes an alternator 101, a high voltage system circuit 102, a low voltage system circuit 103, and a changeover switch 104.

  The alternator 101 is connected to the output shaft of the internal combustion engine 1 (or a member that rotates in conjunction with the output) via a pulley, a belt, or the like, and generates power that converts the kinetic energy (rotational energy) of the output shaft into electrical energy. Machine.

  Specifically, the alternator 101 includes a stator coil having a three-phase winding, a field coil wound around the rotor, a rectifier that rectifies an alternating current generated in the stator coil into a direct current, and a field current for the field coil. This is a three-phase AC generator including a regulator 101a that switches between energization (on) and non-energization (off) of (field current). The alternator 101 configured in this manner generates an induced current (three-phase alternating current) in the stator coil when a field current is applied to the field coil, and rectifies the generated three-phase alternating current into a direct current. Output.

  The output of the alternator 101 is input to the input terminal 104 a of the changeover switch 104. The changeover switch 104 is a circuit that includes one input terminal 104a and two output terminals 104b and 104c, and switches the connection destination of the input terminal 104a to one of the two output terminals 104b and 104c. One of the two output terminals 104 b and 104 c (hereinafter referred to as “first output terminal”) 104 b is connected to the high voltage circuit 102. The other of the two output terminals 104 b and 104 c (hereinafter referred to as “second output terminal”) 104 c is connected to the low voltage system circuit 103.

  The high voltage system circuit 102 is a circuit capable of inputting and outputting high voltage (for example, about 43.5 V) electricity, and is a circuit in which a high voltage battery 102a and a high voltage load 102b are connected in parallel. On the other hand, the low voltage system circuit 103 is a circuit that can input and output low voltage (for example, about 14.5 V) electricity, and is a circuit in which a low voltage battery 103a and a low voltage load 103b are connected in parallel.

  Returning to FIG. 1, the vehicle is provided with an electronic control unit (ECU) 20 for electrically controlling the internal combustion engine 1, the transmission 2, and the power generation mechanism 100. In FIG. 1, there is one ECU 20, but the ECU 20 may be divided into an ECU for the internal combustion engine 1, an ECU for the transmission 2, and an ECU for the power generation mechanism 100.

  The ECU 20 is supplied with output signals from various sensors such as an accelerator position sensor 21, a shift position sensor 22, a brake switch 23, a crank position sensor 24, and a vehicle speed sensor 25.

  The accelerator position sensor 21 is a sensor that outputs an electrical signal corresponding to the operation amount (depression amount) of the accelerator pedal. The shift position sensor 22 is a sensor that outputs an electrical signal corresponding to the operation position of the shift lever. The brake switch 23 is a sensor that outputs an ON signal when the brake pedal is depressed. The crank position sensor 24 is a sensor that outputs an electrical signal corresponding to the rotational position of the output shaft (crankshaft) of the internal combustion engine 1. The vehicle speed sensor 25 is a sensor that outputs an electrical signal corresponding to the traveling speed of the vehicle.

  The ECU 20 controls the operation state of the internal combustion engine 1, the speed change state of the transmission 2, the power generation state of the power generation mechanism 100, and the like based on the output signals of the various sensors described above. Hereinafter, a method for controlling the power generation state of the power generation mechanism 100 will be described.

The ECU 20 changes the generated voltage of the alternator 101 by duty-controlling on / off of the regulator 101a. For example, when increasing the power generation voltage of the alternator 101, the ECU 20 determines the duty ratio so that the regulator 101a has a long on-time (short off-time). On the other hand, when lowering the generated voltage of the alternator 101, the ECU 20 determines the duty ratio so that the ON time of the regulator 101a is short (off time is long). Further, the ECU 20 senses the actual power generation voltage of the alternator 101, and also performs feedback control of the duty ratio according to the difference between the actual power generation voltage and the target power generation voltage.

  In addition, when supplying electricity to the high voltage system circuit 102, the ECU 20 controls the duty of the regulator 101a so that the generated voltage of the alternator 101 matches the voltage (high voltage) suitable for the high voltage system circuit 102. The changeover switch 104 is controlled so that the input terminal 104a and the first output terminal 104b are connected.

  On the other hand, when supplying electricity to the low voltage system circuit 103, the ECU 20 controls the duty of the regulator 101a so that the generated voltage of the alternator 101 matches the voltage (low voltage) suitable for the low voltage system circuit 103. The changeover switch 104 is controlled so that the input terminal 104a and the second output terminal 104c are connected.

  By the way, when the driving state of the vehicle is in a non-decelerated state, in other words, when the power generation voltage of the alternator 101 is increased to a high voltage when the vehicle is in an acceleration state or a constant speed state, the power (kinetic energy) generated by the internal combustion engine 1 ) Increases the proportion of kinetic energy consumed by the alternator 101. Therefore, the driving force of the driving wheel 6 may be excessively reduced. Furthermore, if the load on the internal combustion engine 1 is increased with respect to the decrease in driving force described above, the fuel consumption may increase.

  On the other hand, when the power generation voltage of the alternator 101 is lowered to a low voltage when the vehicle is in a decelerating state, the proportion of the kinetic energy regenerated by the alternator 101 in the kinetic energy of the drive wheels 6 decreases. Therefore, the kinetic energy consumed (discarded after being converted into thermal energy) by the braking device (for example, friction brake) increases.

  Therefore, in the power generation control of this embodiment, as shown in FIG. 3, when the vehicle running state is in the non-decelerated state, the power generation voltage of the alternator 101 is suppressed to a low voltage, and the vehicle running state is in the decelerated state. In some cases, the power generation voltage of the alternator 101 was increased to a high voltage.

  The running state of the vehicle is determined based on output signals from the accelerator position sensor 21 and the vehicle speed sensor 25. For example, the ECU 20 determines that the vehicle is in a deceleration state when the accelerator opening is zero and the vehicle speed tends to decrease. Further, when the accelerator opening is larger than zero and the vehicle speed tends to increase, the ECU 20 determines that the vehicle is in an acceleration state. Further, the ECU 20 determines that the vehicle is in a constant speed state when the accelerator opening is in a partial state and the change rate of the vehicle speed is within a certain range.

  In this way, by changing the power generation voltage of the alternator 101 according to the acceleration / deceleration state of the vehicle, the kinetic energy discarded during deceleration traveling is suppressed while suppressing the increase in kinetic energy consumed during power generation during acceleration traveling or constant speed traveling. Can be reduced.

  However, when the vehicle running state shifts from the non-decelerating state to the decelerating state, if the power generation voltage of the alternator 101 is temporarily changed from a low voltage to a high voltage, the vehicle deceleration rate rapidly increases. Therefore, there is a possibility of giving the driver a shock or discomfort.

  In particular, when the driver requests a relatively gentle deceleration, if the power generation voltage of the alternator 101 is changed from a low voltage to a high voltage at a time, a deceleration force more than the driver intends is generated. Therefore, a driving operation for correcting it is necessary, and drivability is lowered.

Similarly, the alternator 10 when the running state of the vehicle shifts from the deceleration state to the non-deceleration state.
When the power generation voltage 1 is changed from a high voltage to a low voltage at a time, the deceleration of the vehicle rapidly decreases. Therefore, the driver may be shocked and discomforted, and drivability may be reduced.

  On the other hand, in the power generation control of this embodiment, when the power generation voltage of the alternator 101 is changed from one of the low voltage and the high voltage to the other, the target power generation voltage of the alternator 101 is subjected to a smoothing process.

  For example, when the vehicle running state shifts from the non-decelerating state to the decelerating state, the target power generation voltage of the alternator 101 is gradually increased from a low voltage to a high voltage as shown in FIG. At that time, the time required for the target power generation voltage to reach the high voltage from the low voltage (time constant a) is a time constant peculiar to the alternator 101 (the time required for the power generation voltage of the alternator 101 to reach the high voltage from the low voltage). Response delay time) is set to be larger.

  Moreover, although the example shown in FIG. 4 shows an example in which the target power generation voltage changes linearly, it may change in a quadratic curve or in steps. Furthermore, although the example shown in FIG. 4 shows the case where the vehicle running state has shifted from the non-decelerated state to the decelerated state, the target of the alternator 101 is also applied when the vehicle running state has shifted from the decelerated state to the non-decelerated state. The generated voltage may be annealed.

  When the target generated voltage of the alternator 101 is smoothed in this way, the difference between the acceleration / deceleration rate requested by the driver and the actual acceleration / deceleration rate is reduced.

  Note that when the required acceleration / deceleration rate exceeds a predetermined reference, the above-described annealing process may not be performed. In other words, when the driver requests rapid acceleration / deceleration, the target power generation voltage of the alternator 101 may be temporarily changed from one of the low voltage and the high voltage to the other.

  When the target power generation voltage of the alternator 101 is changed by such a method, the difference between the required acceleration / deceleration rate and the actual acceleration / deceleration rate can be reduced. Therefore, a decrease in drivability can be suppressed.

  Next, a method for determining whether or not the required acceleration / deceleration rate exceeds the standard will be described. In this embodiment, the acceleration / deceleration required for the vehicle is determined based on the output signals of the accelerator position sensor 21, the shift position sensor 22, and the brake switch 23.

  First, when the vehicle is in a deceleration state, if the shift position is at a high speed (or the gear ratio of the transmission 2 is higher than the reference gear ratio) and the brake switch 23 is off, the required deceleration rate is It can be determined that the value is low. On the other hand, if the shift position is at the low speed (or the transmission gear ratio of the transmission 2 is a constant speed side from the reference gear ratio) and / or the brake switch 23 is on, it is determined that the required deceleration rate is high. Can do.

  When a sensor capable of detecting the operation amount of the brake pedal is mounted on the vehicle, it is determined whether or not the operation amount of the brake pedal is larger than the reference operation amount instead of the on / off signal of the brake switch 23. The result may be a parameter.

Next, when the vehicle is in an acceleration state, if the accelerator opening is smaller than the reference opening and the increase speed of the accelerator opening is lower than the reference speed, it can be determined that the required acceleration is low. On the other hand, when the accelerator opening is larger than the reference opening, or when the increasing speed of the accelerator opening is higher than the reference speed, it can be determined that the required acceleration is high.

  The reference gear ratio, the reference operation amount, the reference opening degree, and the reference speed described above are determined in advance by adaptation work using experiments or the like.

  Hereinafter, the power generation control in this embodiment will be described with reference to FIG. FIG. 5 is a flowchart showing a power generation control routine in the present embodiment. This routine is stored in advance in the ROM or the like of the ECU 20, and is periodically executed by the ECU 20.

  In the routine of FIG. 5, first, the ECU 20 acquires the traveling state of the vehicle from the output signals of the accelerator position sensor 21 and the vehicle speed sensor 25 in S101.

  In S102, the ECU 20 determines whether or not the traveling state of the vehicle is in a deceleration state. If an affirmative determination is made in S102, the ECU 20 proceeds to S103.

  In S103, the ECU 20 determines whether or not it is immediately after the start of deceleration. In short, the ECU 20 determines whether or not the power generation voltage of the alternator 101 is not switched from the low voltage Vl to the high voltage Vh. If an affirmative determination is made in S103, the ECU 20 proceeds to S104.

  In S104, the ECU 20 determines whether or not a low voltage stop condition is satisfied. The low voltage stop condition is a condition that is satisfied when power supply from the alternator 101 to the low voltage system circuit 103 can be stopped. The power supply from the alternator 101 to the low voltage system circuit 103 can be stopped when the state of charge (SOC) of the low voltage battery 103a is equal to or higher than a predetermined lower limit and / or the low voltage load 103b. The case where the required power is less than or equal to a predetermined upper limit value can be exemplified.

  Further, in order for the alternator 101 to generate the high voltage Vh, the number of rotations of the alternator 101 needs to be equal to or higher than a certain number of rotations. Therefore, it is desirable to add a condition that the number of rotations of the alternator 101 is equal to or higher than a certain number of rotations as one of the low voltage stop conditions. Since the rotation speed of the alternator 101 correlates with the rotation speed of the internal combustion engine 1 (engine rotation speed), the engine rotation speed may be a predetermined rotation speed or more.

  If an affirmative determination is made in S104, the ECU 20 proceeds to S105. In S105, the ECU 20 controls the changeover switch 104 so as to switch from the state where the input terminal 104a and the second output terminal 104c are connected to the state where the input terminal 104a and the first output terminal 104b are connected. That is, the ECU 20 controls the changeover switch 104 so as to switch from the state where the alternator 101 and the low voltage system circuit 103 are connected to the state where the alternator 101 and the high voltage system circuit 102 are connected.

  In S <b> 106, the ECU 20 acquires the deceleration rate (requested deceleration rate) requested by the driver. Acquisition of the required deceleration rate is performed based on the output signal of the shift position sensor 22 and the output signal of the brake switch 23 as described above.

  In S107, the ECU 20 determines whether or not the required deceleration rate acquired in S106 is below a reference. If an affirmative determination is made in S107, the ECU 20 proceeds to S108. On the other hand, if a negative determination is made in S107, the ECU 20 skips S108 and proceeds to S109.

In S108, the ECU 20 performs a smoothing process on the target generated voltage when the generated voltage of the alternator 101 is changed from the low voltage Vl to the high voltage Vh. At that time, the time constant “a” used for the smoothing process of the target generated voltage may be a fixed value adapted in advance, or a variable value that changes stepwise or continuously according to the required deceleration rate. Also good.

  In S109, the ECU 20 controls the regulator 101a so that the power generation voltage of the alternator 101 matches the target power generation voltage determined in S108. Note that if a negative determination is made in S107, the ECU 20 skips S108 and proceeds to S109, but the target power generation voltage that has not been subjected to the annealing process is used as the target power generation voltage in that case. . That is, the target power generation voltage is temporarily changed from the low voltage Vl to the high voltage Vh.

  If the required deceleration rate exceeds the standard while the actual power generation voltage is gradually increased by the target power generation voltage annealing process, the annealing process is stopped and the target power generation voltage is immediately set to the high voltage Vh. You may change to

  In S110, the ECU 20 determines whether or not the actual generated voltage of the alternator 101 has risen above the high voltage Vh. If a negative determination is made in S110, the ECU 20 returns to S109. On the other hand, if a positive determination is made in S110, the ECU 20 proceeds to S111.

  In S111, the ECU 20 feedback-controls the duty ratio of the regulator 101a so that the actual generated voltage of the alternator 101 is maintained at the high voltage Vh.

  Next, when a negative determination is made in S102 described above and a negative determination is made in S103 described above, the ECU 20 proceeds to S112. In S112, the ECU 20 determines whether or not it is immediately after the end of deceleration. That is, the ECU 20 determines whether or not the generated voltage of the alternator 101 is not switched from the high voltage Vh to the low voltage Vl.

  When a negative determination is made in S112 (when the generated voltage of the alternator 101 has been changed from the high voltage Vh to the low voltage Vl), the ECU 20 proceeds to S119, and the generated voltage of the alternator 101 is maintained at the low voltage Vl. Thus, the duty ratio of the regulator 101a is feedback controlled.

  On the other hand, if an affirmative determination is made in S112, the ECU 20 proceeds to S113. In S113, the ECU 20 controls the changeover switch 104 so as to switch from the state where the input terminal 104a and the first output terminal 104b are connected to the state where the input terminal 104a and the second output terminal 104c are connected. That is, the ECU 20 controls the changeover switch 104 so as to switch from a state where the alternator 101 and the high voltage system circuit 102 are connected to a state where the alternator 101 and the low voltage system circuit 103 are connected.

  In S <b> 114, the ECU 20 acquires the acceleration degree (requested acceleration degree) requested by the driver. Subsequently, the ECU 20 proceeds to S115, and determines whether or not the required acceleration obtained in S114 is below a reference. If an affirmative determination is made in S115, the ECU 20 proceeds to S116.

  In S116, the ECU 20 executes a smoothing process on the target generated voltage when the generated voltage of the alternator 101 is changed from the high voltage Vh to the low voltage Vl. In this case, the time constant a used for the target power generation voltage smoothing process may be a fixed value that is adapted in advance, or a variable value that changes stepwise or continuously according to the required acceleration. Also good.

  In S117, the ECU 20 controls the regulator 101a so that the power generation voltage of the alternator 101 matches the target power generation voltage determined in S116. If a negative determination is made in S115, the ECU 20 skips S116 and proceeds to S117. In this case, the target generated voltage that has not been subjected to the annealing process is used as the target generated voltage. . That is, the target power generation voltage is temporarily changed from the high voltage Vh to the low voltage Vl.

  In the middle of the actual power generation voltage being gradually reduced by the target power generation voltage smoothing process, if the required acceleration level becomes high, the smoothing process is stopped and the target power generation voltage is reduced to the low voltage Vl. You may change it immediately.

  In S118, the ECU 20 determines whether or not the actual power generation voltage of the alternator 101 has dropped below the low voltage Vl. If a negative determination is made in S118, the ECU 20 returns to S117. On the other hand, if a positive determination is made in S118, the ECU 20 proceeds to S119.

  In S119, the ECU 20 feedback-controls the duty ratio of the regulator 101a so that the actual generated voltage of the alternator 101 is maintained at the low voltage Vl.

  If a negative determination is made in S104 described above, the ECU 20 proceeds to S119. That is, the ECU 20 maintains the generated voltage of the alternator 101 at the low voltage Vl. In this case, it is possible to avoid a situation where power is insufficient in the low voltage system circuit 103, a situation where the power generation voltage of the alternator 101 does not rise to the high voltage Vh, and the like.

  Thus, when the ECU 20 executes the routine of FIG. 5, the detection means and control means according to the present invention are realized. Therefore, it is possible to change the power generation voltage of the alternator 101 according to the acceleration / deceleration required by the driver, and it is possible to suppress a decrease in the drivability of the vehicle in the transition period of the power generation voltage change.

  In the present embodiment described above, the example in which the target power generation voltage smoothing process is not performed when the required acceleration / deceleration rate exceeds the standard is described. However, when the required acceleration / deceleration rate exceeds the standard, the required acceleration / deceleration rate is not corrected. The annealing process may be performed using a smaller time constant than when the speed is below the reference.

<Example 2>
Next, a second embodiment of the present invention will be described with reference to FIGS. Here, a configuration different from that of the first embodiment will be described, and description of the same configuration will be omitted.

  In the first embodiment described above, the example in which the target generated voltage is gradually changed in the transition period in which the generated voltage of the alternator 101 is changed has been described. In contrast, in the present embodiment, an example in which the generated voltage is once lowered to a voltage lower than the low voltage Vl before the change of the generated voltage is started in the transition period in which the generated voltage of the alternator 101 is changed will be described.

  FIG. 6 is a timing chart showing a method for changing the target power generation voltage and the changeover timing of the changeover switch 104 when the vehicle running state shifts from the non-decelerating state to the decelerating state.

As shown in FIG. 6, the ECU 20 first sets the target power generation voltage of the alternator 101 to a predetermined voltage lower than the low voltage Vl (“0” in the example shown in FIG. 6) when the vehicle traveling state shifts to the non-decelerating state. To lower. Subsequently, the ECU 20 switches the changeover switch 104 when the actual power generation voltage of the alternator 101 drops to a predetermined voltage. Further, the ECU 20 changes the target generated voltage of the alternator 101 to the high voltage Vh after the changeover operation of the changeover switch 104.

  When the target power generation voltage is changed by such a procedure, it is possible to avoid a situation in which the power generation voltage of the alternator 101 is suddenly changed from the low voltage Vl to the high voltage Vh. Therefore, it is possible to avoid a situation in which the acceleration / deceleration rate of the vehicle suddenly changes, and to reduce the load acting on the changeover switch 104, the alternator driving belt and the pulley. As a result, it is possible to suppress a decrease in drivability and to improve the durability of the changeover switch 104 and the like.

  Hereinafter, power generation control in this embodiment will be described with reference to FIG. FIG. 7 is a flowchart showing a power generation control routine in the present embodiment. In FIG. 7, the same steps as those in the routine of the first embodiment (see FIG. 5) described above are denoted by the same reference numerals.

  In the routine of FIG. 7, the ECU 20 sequentially executes the processes of S106 and S107 when an affirmative determination is made in S104. And when affirmation determination is carried out in S107, ECU20 performs the process of S201. In S201, the ECU 20 executes a power generation voltage reduction process. As described in the description of FIG. 6, the generated voltage reduction process is a process for reducing the generated voltage of the alternator 101 from the low voltage Vl to “0” (power generation is stopped).

  The ECU 20 executes the process of S202 after executing the process of S201. In S202, the ECU 20 determines whether or not the actual generated voltage of the alternator 101 has decreased to “0”. The process of S202 is repeatedly executed until the actual generated voltage of the alternator 101 becomes “0”.

  If an affirmative determination is made in S202, the ECU 20 executes the process of S203. In S203, the ECU 20 controls the changeover switch 104 to switch from the state where the alternator 101 and the low voltage system circuit 103 are connected to the state where the alternator 101 and the high voltage system circuit 102 are connected. Then, ECU20 performs the process of S109-S111.

  If a negative determination is made in S107, the ECU 20 skips S201 and S202 described above and proceeds to S203. That is, when the required deceleration rate exceeds the reference, the switching operation of the changeover switch 104 and the change of the generated voltage are performed without executing the generated voltage reduction process.

  Next, when an affirmative determination is made in S112, the ECU 20 sequentially executes the processes of S114 and S115. If an affirmative determination is made in S115, the ECU 20 executes the process of S204. In S204, the ECU 20 executes a power generation voltage reduction process. In this case, the power generation voltage reduction process is a process of reducing the power generation voltage of the alternator 101 from the high voltage Vh to “0” (power generation is stopped).

  The ECU 20 executes the process of S205 after executing the process of S204. In S205, the ECU 20 determines whether or not the actual generated voltage of the alternator 101 has decreased to “0”. The process of S205 is repeatedly executed until the actual generated voltage of the alternator 101 becomes “0”.

If an affirmative determination is made in S205, the ECU 20 executes the process of S206. In S206, the ECU 20 controls the changeover switch 104 to switch from the state where the alternator 101 and the high voltage system circuit 102 are connected to the state where the alternator 101 and the low voltage system circuit 103 are connected. Then, ECU20 performs the process of S117.

  The ECU 20 executes the process of S207 after executing the process of S117. In S207, the ECU 20 determines whether or not the actual power generation voltage of the alternator 101 has increased to the low voltage Vl or higher. If a negative determination is made in S207, the ECU 20 returns to S117. On the other hand, if an affirmative determination is made in S207, the ECU 20 proceeds to S119.

  If a negative determination is made in S115, the ECU 20 skips S204 and S205 described above and proceeds to S206. That is, when the required deceleration rate exceeds the reference, the switching operation of the changeover switch 104 and the change of the generated voltage are performed without executing the generated voltage reduction process.

  If the required acceleration / deceleration rate exceeds the standard during the power generation reduction process, the ECU 20 stops the power generation reduction process and immediately performs the switching operation of the changeover switch 104 and the change of the target power generation voltage. Also good.

  In this way, the ECU 20 can execute the routine of FIG. 7 to change the power generation voltage of the alternator 101 according to the acceleration / deceleration required by the driver, and the drivability of the vehicle in the transition period of the power generation voltage change. The decrease can be suppressed. Further, it is possible to improve the durability of the changeover switch 104 and the like.

  In the present embodiment described above, an example has been described in which the generation voltage reduction process is not performed when the required acceleration / deceleration rate exceeds the standard, but when the required acceleration / deceleration rate exceeds the standard, the required acceleration / deceleration rate is not The power generation voltage reduction process may be performed while increasing the predetermined voltage from when it is below the reference.

  The ECU 20 may execute a combination of the annealing process of the first embodiment and the generated voltage reduction process of the present embodiment. For example, the ECU 20 may perform the smoothing process when raising the power generation voltage of the alternator 101 to the high voltage Vh or the low voltage Vl after the power generation voltage reduction process.

  Further, the ECU 20 detects the actual acceleration / deceleration rate during or after changing the power generation voltage of the alternator 101, and generates power of the alternator 101 so that the detected acceleration / deceleration rate matches the required acceleration / deceleration rate. The voltage may be feedback controlled. For example, when the actual deceleration rate exceeds the required deceleration rate, or when the actual acceleration rate falls below the required acceleration rate, the ECU 20 may control the regulator 101a so as to decrease the power generation voltage of the alternator 101. .

  As an actual acceleration / deceleration detection method, a calculation method based on the output signal of the vehicle speed sensor 25 can be exemplified. When an acceleration sensor is mounted on the vehicle, the output signal of the acceleration sensor may be used as the actual acceleration / deceleration rate.

  Moreover, as a power generation mechanism to which the present invention is applied, a power generation mechanism having a configuration as shown in FIG. 8 can be used. In FIG. 8, the high voltage system circuit 102 and the low voltage system circuit 103 are electrically connected via a DC-DC converter (DC-DC converter) 105. The DC-DC converter 105 is a circuit that steps down the high voltage Vh flowing through the high voltage system circuit 102 to the low voltage Vl and supplies it to the low voltage system circuit 103 by the switching operation of the built-in power transistor, and is controlled by the ECU 20. Is done.

  According to the power generation mechanism configured as described above, when it is determined in S104 of FIGS. 5 and 7 described above that the state of charge (SOC) of the low voltage battery 103a is less than a predetermined lower limit, and / or Alternatively, even when it is determined that the required power of the low voltage load 103b exceeds a predetermined upper limit value, the generated voltage of the alternator 101 can be switched from the low voltage Vl to the high voltage Vh. As a result, it is possible to increase the regenerative amount of kinetic energy while avoiding a situation where power is insufficient in the low-voltage system circuit 103.

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 2 Transmission 3 Propeller shaft 4 Differential gear 5 Drive shaft 6 Drive wheel 20 ECU
100 power generation mechanism 101 alternator 101a regulator 102 high voltage system circuit 102a high voltage battery 102b high voltage load 103 low voltage system circuit 103a low voltage battery 103b low voltage load 104 changeover switch 104a input terminal 104b first output terminal 104c second output terminal

Claims (7)

An alternator that operates using the kinetic energy of the motor or wheels of the vehicle and can change the generated voltage;
A low-voltage circuit connected to the first power storage device;
A high voltage system circuit connected to a second power storage device capable of inputting and outputting a higher voltage than the first power storage device;
A changeover switch for switching a supply destination of electricity generated by the alternator to either the low voltage system circuit or the high voltage system circuit in accordance with the power generation voltage of the alternator;
Detecting means for detecting the acceleration / deceleration required for the vehicle;
In the transition period in which the generated voltage of the alternator is changed from a voltage suitable for one of the low voltage system circuit and the high voltage system circuit to a voltage suitable for the other, the generated voltage of the alternator according to the detection result of the detection means Control means for adjusting,
A vehicle power generation control system comprising:   2. The power generation control system for a vehicle according to claim 1, wherein the control means slows the change speed of the power generation voltage of the alternator when the acceleration / deceleration required for the vehicle is low compared to when it is high.   2. The control unit according to claim 1, wherein the control means temporarily lowers the power generation voltage of the alternator to a predetermined voltage set lower than a voltage suitable for the low voltage system circuit before starting to change the power generation voltage of the alternator. A power generation control system for a vehicle, wherein the changeover switch is switched when the power generation voltage of the alternator is equal to or lower than the predetermined voltage.   4. The control device according to claim 3, wherein when the acceleration / deceleration detected by the detection device exceeds a predetermined reference, the control device immediately starts changing the power generation voltage of the alternator and switching the changeover switch. A power generation control system for a vehicle.   5. The vehicle power generation according to claim 1, wherein the detection unit determines the acceleration / deceleration based on at least one of an accelerator opening, a state of a braking device, and a state of a transmission. Control system.   5. The control unit according to claim 4, wherein when the vehicle decelerates, the control means has a braking operation amount greater than a predetermined reference operation amount, and / or the transmission speed ratio is lower than a predetermined reference speed ratio. And determining that the deceleration required for the vehicle exceeds a reference, a power generation control system for a vehicle.   5. The control device according to claim 4, wherein when the accelerator opening is larger than a predetermined reference opening at the time of acceleration of the vehicle, or when the increasing speed of the accelerator opening is higher than a predetermined reference speed. A power generation control system for a vehicle, characterized in that it is determined that an acceleration required for the vehicle exceeds a reference.

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