JP5569211B2 - Vehicle regenerative power generation control system - Google Patents

Description

  The present invention relates to a regenerative power generation control technology that converts kinetic energy of a vehicle into electric energy when the vehicle is decelerated.

  In a system that performs regenerative power generation by operating a generator using the kinetic energy of a vehicle when the vehicle is in a decelerating running state, the upper limit value of the generated power according to the state of charge (SOC) of the battery Is known (see, for example, Patent Document 1).

JP 2006-238528 A JP 2005-161216 A JP 2005-304157 A JP 2009-292386 A

  According to the conventional technique described above, a control logic is required for changing the operating state (generated power) of the generator in accordance with the state of charge of the battery. Further, when the power generated by the generator is changed, the magnitude of the regenerative braking force changes. For this reason, in order to converge the vehicle deceleration to the driver's required value, a control logic for adjusting the braking force of the friction braking device in accordance with the magnitude of the regenerative braking force is also required.

  The present invention has been made in view of the various circumstances as described above, and an object of the present invention is to generate regenerative power by operating a generator using kinetic energy of the vehicle when the vehicle decelerates. The purpose of the control system is to simplify the control logic while expanding the regenerative amount of kinetic energy.

  In order to solve the above-described problems, the present invention can recharge a battery in a regenerative power generation control system for a vehicle that performs regenerative power generation by operating a generator using kinetic energy of the vehicle during vehicle deceleration. The power generated during regenerative power generation is determined based on the state of charge at which the power is maximized.

Specifically, the present invention relates to a regenerative power generation control system for a vehicle that performs regenerative power generation by operating a generator using kinetic energy of the vehicle when the vehicle decelerates.
A battery for storing electric power regenerated by the generator;
An acquisition means for acquiring a reference charging state that is a charging state of the battery when electric power that can be charged to the battery is maximized;
Control means for determining the target generated power at the time of regenerative power generation assuming that the state of charge of the battery is in a reference charge state;
I was prepared to.

Conventionally, the amount of work (generated power) of the generator during regenerative power generation is limited to the amount of power that can be received by the battery (hereinafter referred to as “chargeable power”). The magnitude of the chargeable power varies depending on the state of charge of the battery. Therefore, the work amount when the generator performs regenerative power generation changes according to the state of charge of the battery. As a result, the magnitude of the regenerative braking force acting on the vehicle varies depending on the state of charge of the battery, and it is necessary to increase or decrease the braking force of the friction braking device according to the variation.

  On the other hand, the regenerative power generation control system for a vehicle according to the present invention determines the work amount of the generator by assuming that the state of charge of the battery is in the reference charge state when performing regenerative power generation. That is, the generator performs regenerative power generation using a maximum value of rechargeable power (hereinafter referred to as “maximum rechargeable power”) as a target value. Therefore, the work amount (generated power) of the generator during regenerative power generation is constant (power equivalent to the maximum chargeable power) regardless of the actual charge state of the battery. As a result, the magnitude of the regenerative braking force is also kept constant.

  According to such an invention, the control logic for changing the generated power of the generator according to the state of charge of the battery and the control logic for changing the braking force of the friction braking device according to the magnitude of the regenerative braking force are simplified. can do.

  If the maximum chargeable power is larger than the chargeable power suitable for the actual charge state of the battery (hereinafter referred to as “actually chargeable power”), a part of the generated power is not charged to the battery. become. On the other hand, the regenerative power generation control system of the present invention may supply generated electric power (hereinafter referred to as “surplus generated electric power”) that cannot be charged to a battery to an electric device mounted on the vehicle. In that case, the regeneratively generated power can be used effectively.

  As the above-mentioned electric equipment, in addition to an electric load such as a defogger, an electric water pump, an electric oil pump, or an air conditioner, a heat medium that heats a heat medium (for example, cooling water or lubricating oil) circulating through the internal combustion engine. A heater, a catalyst heater for heating an exhaust purification catalyst disposed in an exhaust passage of the internal combustion engine, a motor-assisted turbo capable of rotating a rotating shaft of a turbocharger by an electric motor, a sub-battery provided separately from the battery described above, Etc. can be illustrated.

  When a plurality of electric devices as described above are mounted on a vehicle, the surplus generated power supply destination or the supply destination is determined according to the temperature of the heat medium, the temperature of the exhaust purification catalyst, or the charging state of the sub-battery. A priority may be determined.

  For example, when the temperature of the heat medium is lower than an appropriate temperature (the temperature of the heat medium after completion of warming up of the internal combustion engine), surplus generated power may be preferentially supplied to the heat medium heater. In this case, the friction of the internal combustion engine is reduced and the combustion state is improved, so that the fuel consumption rate can be improved and the exhaust emission can be reduced.

  When the temperature of the exhaust purification catalyst is lower than the activation temperature (the temperature at which the purification function of the exhaust purification catalyst is activated), or it is determined that the temperature of the exhaust purification catalyst may fall below the activation temperature during deceleration traveling. In such a case, surplus generated power may be preferentially supplied to the catalyst heater. In this case, the exhaust purification catalyst can be activated at an early stage or the temperature reduction of the exhaust purification catalyst can be suppressed, so that exhaust emission can be reduced.

  If it is predicted that the vehicle will accelerate after decelerating, surplus generated power may be preferentially supplied to the motor-assisted turbo. In this case, the turbo lag at the time of reacceleration can be kept small, and the fuel consumption rate can be improved and the exhaust emission can be reduced.

In addition, when it is not necessary to supply surplus generated power to an electric device other than the sub battery and the sub battery is in a chargeable state or when the sub battery is in a low charge state, surplus generated power is preferentially given to the sub battery. May be supplied. In this case, it is possible to avoid a situation in which surplus generated power is discarded (for example, heat is released after being converted into thermal energy using a resistor or the like), and the state of charge of the sub-battery can be increased.

  The power that can be generated by the generator (hereinafter referred to as “power that can be generated”) is limited by the rotational speed and temperature of the generator. For example, when the rotational speed of the generator is low or when the temperature of the generator is high, the power that can be generated may be less than the maximum charge power. In such a case, regenerative power generation may be performed using the power that can be generated as a target value, and regenerative power generation may be performed using the chargeable power corresponding to the state of charge of the battery as a target value.

  According to the present invention, in a regenerative power generation control system that performs regenerative power generation by operating a generator using kinetic energy of a vehicle when the vehicle is decelerating, the control logic is simplified while increasing the regenerative amount of kinetic energy. Can be achieved.

1 is a diagram showing a schematic configuration of a vehicle to which the present invention is applied in a first embodiment. It is a figure which shows typically the structure of the electric power generation mechanism in a 1st Example. It is a figure which shows the relationship between the charge condition (SOC) of a high voltage battery, and chargeable power. It is a figure which shows the relationship between a brake pedal stroke and total braking force. It is a flowchart which shows a regenerative power generation control routine. It is a figure which shows schematic structure of the vehicle to which this invention is applied in a 2nd Example. It is a figure which shows typically the structure of the electric power generation mechanism in a 2nd Example. It is a flowchart which shows the distribution control routine of the surplus generated electric power in a 2nd Example. It is a figure which shows schematic structure of the exhaust system of the internal combustion engine in a 3rd Example. It is a figure which shows typically the structure of the electric power generation mechanism in a 3rd Example. It is a flowchart which shows the distribution control routine of the surplus generated electric power in a 3rd Example. It is a figure which shows schematic structure of the intake / exhaust system of the internal combustion engine in a 4th Example. It is a figure which shows typically the structure of the electric power generation mechanism in a 4th Example. It is a flowchart which shows the distribution control routine of the surplus generated electric power in a 4th Example. It is a flowchart which shows the distribution control routine of the surplus generated electric power in a 5th Example.

  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 only 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. The vehicle shown in FIG. 1 is an automobile driven using an internal combustion engine as a prime mover, but may be a hybrid automobile driven using an internal combustion engine and an electric motor as a prime mover, or an electric automobile driven using an electric motor as a prime mover. May be. In short, any vehicle that can perform regenerative power generation that converts the kinetic energy of the vehicle into electrical energy when the vehicle is decelerating is acceptable.

  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 (rotation 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 battery 102, a low voltage battery 103, a changeover switch 104, a DC-DC converter 105, a high voltage electric load 106, and a low voltage electric load 107. .

  The alternator 101 corresponds to the generator according to the present invention. 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 as described above 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 alternator 101 is attached with a temperature sensor 101b for measuring the temperature of the alternator 101.

  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 output terminal (hereinafter referred to as “first output terminal”) 104 b of the two output terminals 104 b and 104 c of the changeover switch 104 is connected to the high voltage battery 102. The other output terminal (hereinafter referred to as “second output terminal”) 104 c of the two output terminals 104 b and 104 c is connected to the low voltage battery 103.

  The high voltage battery 102 corresponds to the battery according to the present invention. The high voltage battery 102 is a battery capable of charging and discharging high voltage (for example, about 42 V) electricity, and is constituted by a lead storage battery, a nickel metal hydride battery, or a lithium ion battery. The high voltage battery 102 is attached with a first SOC sensor 102 a that measures the state of charge (SOC) of the high voltage battery 102.

  The low voltage battery 103 corresponds to a sub battery according to the present invention. The low voltage battery 103 is a battery that can charge and discharge electricity at a voltage (for example, about 14 V) lower than that of the high voltage battery 102, and is constituted by a lead storage battery, a nickel metal hydride battery, or a lithium ion battery. The low voltage battery 103 is provided with a second SOC sensor 103 a that measures the state of charge (SOC) of the low voltage battery 103.

  The DC-DC converter 105 includes a power line (hereinafter referred to as “high voltage power line”) from the first output terminal 104 b of the changeover switch 104 to the high voltage battery 102 and a low voltage from the second output terminal 104 c of the changeover switch 104. A power supply line (hereinafter referred to as a “low voltage power supply line”) that leads to the battery 103, a function of stepping down the electricity flowing through the high voltage power supply line and outputting it to the low voltage power supply line, and a low voltage power supply line It has a function of boosting the electricity flowing through and outputting it to the high voltage power supply line.

  An electrical load (hereinafter referred to as “high voltage electrical load”) 106 that operates by high voltage electrical energy is connected to the above-described high voltage power supply line. Examples of the high voltage electric load 106 include a defogger, an oil heater, an electric water pump, a motor assist turbo, and an electrically heated catalyst.

  An electrical load (hereinafter referred to as “low voltage electrical load”) 107 that operates by low voltage electrical energy is connected to the above-described low voltage power supply line. Examples of the low-voltage electric load 107 include a fuel injection valve, a spark plug, a fuel pump, a headlight, and an ECU 20.

  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 receives output signals from various sensors such as an accelerator position sensor 21, a shift position sensor 22, a brake stroke sensor 23, a crank position sensor 24, a vehicle speed sensor 25, a temperature sensor 101b, a first SOC sensor 102a, and a second SOC sensor 103a. It is designed to be entered.

  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 stroke sensor 23 is a sensor that outputs an electrical signal corresponding to the operation amount (brake pedal stroke) of the brake pedal. 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 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 charging the high voltage battery 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 charging the high voltage battery 102, and the input terminal The changeover switch 104 is controlled so that 104a and the first output terminal 104b are connected.

  On the other hand, when charging the low-voltage battery 103, the ECU 20 controls the duty of the regulator 101a so that the power generation voltage of the alternator 101 matches the voltage (low voltage) suitable for charging the low-voltage battery 103, and the input terminal The changeover switch 104 is controlled so that 104a and the second output terminal 104c are connected.

  Further, when the vehicle is in a decelerating running state, the rotor of the alternator 101 is rotated by the kinetic energy transmitted from the drive wheels 6 to the internal combustion engine 1. At that time, if a field current is applied to the field coil of the alternator 101, the kinetic energy of the drive wheels 6 can be converted into electric energy (regenerative power generation).

  Therefore, the ECU 20 applies a field current to the field coil of the alternator 101 when the vehicle is in a decelerating running state (when the internal combustion engine 1 is in a decelerating fuel cut operation state), and generates electric power regenerated by the alternator 101. Regenerative power generation control for charging the high voltage battery 102 is performed.

  At that time, it is desirable that the kinetic energy recovered by regenerative power generation is as much as possible. By the way, the electric power (chargeable electric power) that can be accepted by the high voltage battery 102 increases or decreases according to the state of charge of the high voltage battery 102. For example, as shown in FIG. 3, the chargeable power of the high voltage battery 102 tends to decrease when the SOC is low (range S1 in FIG. 3) and when the SOC is high (range S3 in FIG. 3). . Therefore, when the state of charge (SOC) of the high-voltage battery 102 belongs to S1 and S3 in FIG. 3, the kinetic energy recovered by regenerative power generation may be reduced.

  Further, when the generated power of the alternator 101 is changed according to the state of charge (SOC) of the high voltage battery 102, the magnitude of the regenerative braking force acting on the vehicle also changes. Therefore, the total braking force of the vehicle (the sum of the regenerative braking force and the friction braking force) is adjusted by adjusting the braking force by the friction braking device (hereinafter referred to as “friction braking force”) according to the increase or decrease of the regenerative braking force. Needs to converge to the required braking force (braking force corresponding to the brake pedal stroke). Therefore, a control logic for adjusting the generated power of the alternator 101 according to the state of charge (SOC) of the high voltage battery 102, a control logic for adjusting the magnitude of the friction braking force according to the magnitude of the regenerative braking force, and the like are required. Become.

  On the other hand, in this embodiment, when the vehicle is in a decelerating running state, the generated power of the alternator 101 is controlled on the assumption that the charging state of the high voltage battery 102 is in a specific charging state. The specific charging state described above is a charging state (reference charging state) when the chargeable power of the high-voltage battery 102 is maximized (maximum chargeable power). That is, the ECU 20 determines the generated power of the alternator 101 on the assumption that the charging state of the high voltage battery 102 belongs to the range S2 in FIG.

According to such a method, the magnitude of the power generated by the alternator 101 during regenerative power generation is fixed to the same level as the maximum chargeable power. As a result, the magnitude of the regenerative braking force is also fixed at a constant magnitude. Therefore, there is no need for control logic that adjusts the generated power of the alternator 101 according to the state of charge (SOC) of the high-voltage battery 102 or control logic that adjusts the magnitude of the friction braking force according to the magnitude of the regenerative braking force. Therefore, the control logic at the time of regenerative power generation can be simplified. Furthermore, it becomes possible to increase the kinetic energy converted into electric energy at the time of regenerative power generation as much as possible.

  By the way, if the magnitude of the generated power of the alternator 101 is set to be equal to the maximum chargeable power when the brake pedal stroke is small, the total braking force of the vehicle may be excessive with respect to the brake pedal stroke. There is.

  Therefore, as shown in FIG. 4, when the measured value of the brake stroke sensor 23 is equal to or smaller than the predetermined value α, the ECU 20 increases or decreases the generated power of the alternator 101 in proportion to the measured value of the brake stroke sensor 23. When the measured value of 23 is larger than the predetermined value α, the magnitude of the generated power of the alternator 101 may be fixed to the same level as the maximum chargeable power.

  The predetermined value α described above is a friction braking force according to the regenerative braking force (hereinafter referred to as “maximum regenerative braking force”) and the brake pedal stroke when the alternator 101 generates electric power having the same magnitude as the maximum chargeable power. This is the maximum value of the brake pedal stroke which is considered that the sum total with the power exceeds the driver's required braking force, and is determined in advance by an adaptation process using experiments or the like.

  Thus, when the regenerative braking force is adjusted according to the measured value of the brake stroke sensor 23, a situation in which the total braking force becomes excessive when the brake pedal stroke is small (when the driver's required braking force is small) is avoided. can do. As a result, a decrease in drivability of the vehicle can be avoided.

  Further, when the driver of the vehicle performs a downshift operation, the rotational speed of the internal combustion engine 1 increases, and accordingly, the rotational speed of the alternator 101 also increases. Since the generated power of the alternator 101 changes according to the rotational speed of the alternator 101, the generated power and the regenerative braking force may change if a downshift operation is performed during regenerative power generation.

  Thus, when the ECU 20 detects a downshift operation via the shift position sensor 22 during regenerative power generation, it is desirable to change the duty ratio of the field current so that the generated power and the regenerative braking force do not change.

  Further, when the rotational speed of the alternator 101 is low or when the temperature of the alternator 101 is high, the power that can be generated is smaller than when the rotational speed of the alternator 101 is high or the temperature of the alternator 101 is low. Therefore, when the rotational speed of the alternator 101 is low or when the temperature of the alternator 101 is high, the power that can be generated may be smaller than the maximum chargeable power.

Therefore, when the power that can be generated by the alternator 101 is smaller than the maximum charging power, the ECU 20 may set the power that can be actually accepted by the high-voltage battery 102 (actually chargeable power) as the target generated power. The power that can be generated calculated using the rotation speed and temperature of 101 as parameters may be set as the target generated power. Further, the ECU 20 may increase the electric power that can be generated by the alternator 101 to be greater than or equal to the maximum chargeable electric power by increasing the rotational speed of the alternator 101. As a method of increasing the rotation speed of the alternator 101, a method of increasing the rotation speed of the internal combustion engine 1 by changing the gear ratio of the transmission 2 to the deceleration side can be used.

  Further, when the actual state of charge (SOC) of the high voltage battery 102 belongs to the ranges S1 and S3 in FIG. 3 described above, the generated power (maximum chargeable power) of the alternator 101 can be actually charged by the high voltage battery 102. It will exceed the power. Therefore, the ECU 20 supplies surplus generated power (surplus generated power) that cannot be charged to the high voltage battery 102 to electric devices such as the high voltage electric load 106 and the low voltage battery 103. If surplus generated power is consumed in this way, it becomes possible to effectively use the kinetic energy of the vehicle during deceleration traveling.

  Hereinafter, the regenerative power generation control procedure in this embodiment will be described with reference to FIG. FIG. 5 is a flowchart showing a regenerative power generation control routine. This regenerative power generation control routine is stored in advance in the ROM of the ECU 20, and is executed when the brake pedal is operated.

  In the routine of FIG. 5, the ECU 20 first determines whether or not the brake pedal is operated in S101, in other words, whether or not the measured value (brake pedal stroke) of the brake stroke sensor 23 is greater than zero. If a negative determination is made in S101, the ECU 20 once ends the execution of this routine. On the other hand, when a positive determination is made in S101, the ECU 20 proceeds to S102.

  In S <b> 102, the ECU 20 calculates the actual chargeable power Epbat of the high voltage battery 102. At that time, the ECU 20 may calculate the actual chargeable power Epbat from the measured value of the first SOC sensor 102a and the map as shown in FIG. Since the actual chargeable power Epbat of the high voltage battery 102 changes depending on the temperature of the high voltage battery 102, the ECU 20 uses the measured value of the first SOC sensor 102a and the temperature of the high voltage battery 102 as parameters. Epbat may be calculated.

  In S <b> 103, the ECU 20 calculates the electric power Epart that can be generated by the alternator 101. For example, the ECU 20 may calculate the electric power Epart that can be generated using the rotation speed of the alternator 101 and the measured value of the temperature sensor 101b (temperature of the alternator 101) as parameters.

  In S104, the ECU 20 compares the actual chargeable power Epbat obtained in S102 with the power-generating power Epart obtained in S103. At that time, the ECU 20 proceeds to S105 if the power generation possible power Epart is greater than or equal to the actual chargeable power Epbat, and proceeds to S107 if the power generation possible power Epart is smaller than the actual chargeable power Epbat.

  In S104 described above, the maximum chargeable power Epbatmax may be used instead of the actual chargeable power Epbat. In that case, the ECU 20 may proceed to S105 if the power generating power Epart is equal to or greater than the maximum rechargeable power Epbatmax, or may proceed to S107 if the power generating power Epart is smaller than the maximum rechargeable power Epbatmax.

  In S105, the ECU 20 sets the target generated power Ealttrg of the alternator 101 to a value equivalent to the maximum chargeable power Epbatmax. Subsequently, the ECU 20 calculates surplus generated power Epex (= Ealttrg−Epbat) by subtracting the actual chargeable power Epbat from the target generated power Ealttrg (= Epbatmax) in S106. Then, surplus generated power Epex is supplied to the high voltage electric load 106.

  Further, in S107, the ECU 20 sets the target generated power Ealttrg of the alternator 101 to a value equivalent to the actual chargeable power Epbat.

  As described above, when the ECU 20 executes the routine of FIG. 5, the acquisition means, control means, and calculation means according to the present invention are realized. As a result, the control logic can be simplified while increasing the kinetic energy regenerated during regenerative power generation.

<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.

  The difference between the first embodiment and the present embodiment lies in a method of distributing surplus generated power during regenerative power generation. That is, in this embodiment, when a plurality of high voltage electric loads including an oil heater are mounted on the vehicle, surplus generated power is preferentially supplied to the oil heater.

  In the vehicle of this embodiment, as shown in FIGS. 6 and 7, the oil temperature sensor 26 for measuring the temperature of the lubricating oil circulating in the internal combustion engine 1 and the lubricating oil are heated by using high-voltage electric energy. An oil heater 106a is mounted.

  The oil heater 106a is one of the high voltage electric loads 106, and is operated by high voltage electric energy. The vehicle is also equipped with a plurality of high-voltage electric loads 106b different from the oil heater 106a and a distributor 108 that distributes high-voltage electric energy generated by the alternator 101 to the oil heater 106a and other high-voltage electric loads 106. Has been. The distributor 108 is electrically controlled by the ECU 20.

  The lubricating oil here corresponds to the heat medium according to the present invention, and the oil heater 106a corresponds to the heat medium heater according to the present invention.

  In the vehicle regenerative power generation control system configured as described above, when the alternator 101 performs regenerative power generation, if the measured value (oil temperature) of the oil temperature sensor 26 is lower than the appropriate temperature, the ECU 20 uses the surplus power generation power Epex as an oil heater. The distributor 108 is controlled so as to be supplied preferentially to 106a.

  If the surplus generated power Epex is preferentially supplied to the oil heater 106a, the friction of the internal combustion engine 1 is reduced and the combustion state is improved, so that the fuel consumption rate can be improved and the exhaust emission can be reduced. Furthermore, it is possible to avoid a situation in which surplus generated power Epex is discarded (for example, heat is released after being converted into thermal energy using resistance or the like).

  Hereinafter, a procedure for distributing the surplus generated power Epex will be described with reference to FIG. FIG. 8 is a flowchart showing a surplus generated power distribution control routine. This routine is a subroutine executed by the ECU 20 in S106 of the above-described regenerative power generation control routine (see FIG. 5).

  In the routine of FIG. 8, the ECU 20 first determines in S201 whether or not there is surplus generated power Epex. Specifically, the ECU 20 determines whether or not the target generated power Ealttrg is larger than the actual chargeable power Epbat. If a negative determination is made in S201, the ECU 20 ends the execution of this routine. On the other hand, if a positive determination is made in S201, the process proceeds to S202.

In S202, the ECU 20 reads the measured value (oil temperature) Toil of the oil temperature sensor 26.
In S203, the ECU 20 determines whether or not the oil temperature Toil read in S202 is lower than the appropriate temperature Ta. The appropriate temperature Ta corresponds to the oil temperature when the internal combustion engine 1 is in the warm-up completion state.

  If an affirmative determination is made in S203 (Toil <Ta), the ECU 20 proceeds to S204 and calculates the electric power Eoilmax that can be supplied to the oil heater 106a. The electric power Eoilmax here is electric power that can be supplied to the oil heater 106a within a range where excessive temperature rise of the lubricating oil can be avoided. The amount of temperature rise of the lubricating oil by the oil heater 106a correlates with the oil temperature Toil and the flow speed of the lubricating oil (the number of revolutions of the oil pump (the number of engine revolutions)). Therefore, a relationship among the electric power Eoilmax, the oil temperature Toil, and the engine speed may be experimentally obtained in advance and the relationship may be mapped.

  In S205, it is determined whether or not the power Eoilmax obtained in S204 is equal to or greater than the surplus generated power Epex. If an affirmative determination is made in S205 (Epoilmax ≧ Epex), the ECU 20 proceeds to S206 and controls the distributor 108 so that all of the surplus generated power Epex is supplied to the oil heater 106a.

  If a negative determination is made in S205 (Epoilmax <Epex), the ECU 20 proceeds to S207. In S207, the ECU 20 controls the distributor 108 so that the electric power corresponding to the electric power Epoilmax described above is supplied to the oil heater 106a from the surplus generated electric power Epex, and the remaining electric power is supplied to the other high-voltage electric load 106b. To do.

  If a negative determination is made in S203 (Toil ≧ Ta), the ECU 20 proceeds to S208 and distributes the surplus generated power Epex to the high voltage electric load 106b other than the oil heater 106a. To control.

  As described above, when the ECU 20 executes the distribution control routine of FIG. 8, the surplus generated power Epex is preferentially supplied to the oil heater 106a, so that it is possible to improve the fuel consumption rate and reduce the exhaust emission. As a result, the kinetic energy regenerated by regenerative power generation can be used effectively.

  In the present embodiment, the example in which the surplus generated power Epex is preferentially supplied to the oil heater 106a when the measured value (oil temperature) of the oil temperature sensor 26 is lower than the appropriate temperature has been described. When the temperature is lower, the surplus generated power Epex may be preferentially supplied to the oil heater 106a.

<Example 3>
Next, a third embodiment of the present invention will be described with reference to FIGS. Here, a configuration different from the above-described second embodiment will be described, and description of the same configuration will be omitted.

  The difference between the second embodiment and the present embodiment is that a heater for catalyst heating is mounted on the vehicle instead of the oil heater. FIG. 9 is a diagram showing a schematic configuration of an exhaust system of the internal combustion engine 1 in the present embodiment. In FIG. 9, an exhaust gas purification catalyst 51, a catalyst temperature sensor 52 that measures the bed temperature of the exhaust gas purification catalyst 51, and high voltage electric energy are used in an exhaust passage 50 of the internal combustion engine 1. A catalyst heating heater 106c for heating the catalyst 51 is provided.

The catalyst heating heater 106c is one of the high voltage electric loads 106, and is operated by high voltage electric energy. In addition, as shown in FIG. 10, the vehicle has a catalyst heating heater 106.
A plurality of high-voltage electric loads 106b different from c and a distributor 108 for distributing the high-voltage electric energy generated by the alternator 101 to the catalyst heating heater 106c and the other high-voltage electric loads 106 are mounted.

  In the vehicle regenerative power generation control system configured as described above, when the alternator 101 performs regenerative power generation, if the measured value (catalyst bed temperature) of the catalyst temperature sensor 52 is lower than the activation temperature, the ECU 20 uses the surplus power generation power Epex. The distributor 108 is controlled so as to be supplied preferentially to the catalyst heating heater 106c.

  If surplus generated power Epex is preferentially supplied to the catalyst heating heater 106c, the exhaust purification catalyst 51 can be activated at an early stage, so that exhaust emission can be reduced. Furthermore, it is possible to avoid a situation in which the surplus generated power Epex is discarded.

  Hereinafter, a procedure for distributing the surplus generated power Epex in this embodiment will be described with reference to FIG. FIG. 11 is a flowchart showing a surplus generated power distribution control routine. This routine is a subroutine executed by the ECU 20 in S106 of the above-described regenerative power generation control routine (see FIG. 5). In FIG. 11, the same reference numerals are given to the processes equivalent to the distribution control routine (see FIG. 8) of the second embodiment described above.

  In the routine of FIG. 11, if an affirmative determination is made in S201, the ECU 20 proceeds to S301, and reads the measured value (catalyst bed temperature) Tcat of the catalyst temperature sensor 52. Subsequently, the ECU 20 proceeds to S302, and determines whether or not the catalyst bed temperature Tcat read in S301 is lower than the appropriate temperature Tb. The appropriate temperature Tb corresponds to the lowest value in the temperature range in which the purification function of the exhaust purification catalyst 51 is activated.

  If an affirmative determination is made in S302 (Tcat <Tb), the ECU 20 proceeds to S303, and calculates the electric power Epcatmax that can be supplied to the catalyst heating heater 106c. The electric power Epcatmax here is electric power that can be supplied to the catalyst heating heater 106c within a range in which an excessive temperature rise of the exhaust purification catalyst 51 can be avoided. The amount of temperature rise of the catalyst bed temperature by the catalyst heating heater 106c is the catalyst bed temperature Tcat, the temperature of the exhaust gas flowing into the exhaust gas purification catalyst 51, and the flow rate of the exhaust gas flowing into the exhaust gas purification catalyst 51 (of the internal combustion engine 1). It correlates with the amount of intake air (for example, measured value of an air flow meter). Therefore, a relationship among the electric power Epcatmax, the catalyst bed temperature Tcat, the exhaust temperature, and the exhaust flow rate may be experimentally obtained in advance, and the relationship may be mapped.

  In S304, it is determined whether or not the power Epcatmax obtained in S303 is equal to or greater than the surplus generated power Epex. If an affirmative determination is made in S304 (Epcatmax ≧ Epex), the ECU 20 proceeds to S305, and controls the distributor 108 so that all of the surplus generated power Epex is supplied to the catalyst heating heater 106c.

  If a negative determination is made in S304 (Epcatmax <Epex), the ECU 20 proceeds to S306. In S306, the ECU 20 supplies the power corresponding to the above-described power Epcatmax among the surplus generated power Epex to the catalyst heating heater 106c and supplies the remaining power to the other high-voltage electric load 106b. To control.

  If a negative determination is made in S302 (Toil ≧ Tb), the ECU 20 proceeds to S208 and distributes so that all of the surplus generated power Epex is distributed to the high-voltage electric load 106b other than the catalyst heating heater 106c. The device 108 is controlled.

As described above, when the ECU 20 executes the distribution control routine of FIG. 11, the surplus generated power Epex is preferentially supplied to the catalyst heating heater 106c, so that it is possible to improve the fuel consumption rate and reduce the exhaust emission. it can. As a result, the kinetic energy regenerated by regenerative power generation can be used effectively.

  Note that the exhaust purification catalyst 51 is cooled by the low-temperature air while the vehicle is decelerating (during the deceleration fuel cut operation of the internal combustion engine 1). Therefore, when the catalyst bed temperature is in a relatively low temperature range equal to or higher than the activation temperature, there is a possibility that the catalyst bed temperature falls below the activation temperature during the deceleration fuel cut traveling of the vehicle. Therefore, even when the catalyst bed temperature is in a relatively low temperature range equal to or higher than the activation temperature, the surplus generated power Epex may be preferentially supplied to the catalyst heating heater 106c. In this case, it is possible to avoid a situation where the exhaust purification catalyst 51 is deactivated while the vehicle is decelerating, and therefore, it is possible to avoid an increase in exhaust emission after the end of decelerating travel.

  In the present embodiment, the case where the catalyst heating heater 106c is mounted on the vehicle instead of the oil heater 106a in the second embodiment described above is taken as an example. However, the oil heater 106a and the catalyst heating heater 106c are The distribution control of this embodiment can be applied even when mounted on a vehicle and the temperature Toil of the lubricating oil is equal to or higher than the appropriate temperature Ta.

<Example 4>
Next, a fourth embodiment of the present invention will be described with reference to FIGS. Here, a configuration different from the above-described second embodiment will be described, and description of the same configuration will be omitted.

  The difference between the second embodiment and the present embodiment is that a motor-assisted turbo is mounted on the vehicle instead of the oil heater. FIG. 12 is a diagram showing a schematic configuration of the intake and exhaust system of the internal combustion engine 1 in the present embodiment. In FIG. 12, the vehicle includes a centrifugal supercharger (turbocharger) 54 including a turbine 54 a disposed in the exhaust passage 50 of the internal combustion engine 1 and a compressor 54 b disposed in the intake passage 53 of the internal combustion engine 1. Is installed.

  The turbocharger 54 is a motor-assisted turbo that can rotate and drive a rotating shaft that connects a turbine wheel and a compressor wheel by an electric motor 106d. The electric motor 106d of the motor assist turbo 54 configured as described above is electrically controlled by the ECU 20.

  The electric motor 106d is one of the high voltage electric loads 106, and is operated by high voltage electric energy. Further, as shown in FIG. 13, the vehicle has a plurality of high-voltage electric loads 106b different from the electric motor 106d and high-voltage electric energy generated by the alternator 101 to the electric motor 106d and other high-voltage electric loads 106. A distributor 108 for distributing is mounted.

  In the vehicle regenerative power generation control system configured as described above, when the alternator 101 performs regenerative power generation, if the ECU 20 is predicted to shift to acceleration travel after decelerating travel, the surplus power generation power Epex is transferred to the electric motor 106d. The distributor 108 is controlled to supply with priority.

When surplus generated power Epex is preferentially supplied to the electric motor 106d, the turbo lag is reduced during acceleration traveling after decelerating traveling, and it is necessary to increase the rotational speed of the motor-assisted turbo 54 (the rotational speed of the rotating shaft). Heat energy (amount of fuel) can be reduced. As a result, the drivability of the vehicle is enhanced, and exhaust emission and fuel injection amount can be reduced. Furthermore, it is possible to avoid a situation in which the surplus generated power Epex is discarded.

  Hereinafter, the distribution procedure of surplus generated power Epex in the present embodiment will be described with reference to FIG. FIG. 14 is a flowchart showing a surplus generated power distribution control routine. This routine is a subroutine executed by the ECU 20 in S106 of the above-described regenerative power generation control routine (see FIG. 5). In FIG. 14, the same reference numerals are assigned to the processes equivalent to the distribution control routine (see FIG. 8) of the second embodiment described above.

  In the routine of FIG. 14, if an affirmative determination is made in S201, the ECU 20 proceeds to S401 and acquires re-acceleration information of the vehicle. For example, information such as the state of a signal in front of the vehicle, the inter-vehicle distance from the preceding vehicle, passage of a toll gate on the highway, and the shape of the road are obtained from traffic information using the navigation system.

  In S402, the ECU 20 determines whether or not the vehicle is reaccelerated after decelerating from the information acquired in S401. For example, the ECU 20 changes the signal in front of the vehicle from “stop (red)” to “progress (blue)”, increases the distance between the vehicle and the front car, passes through the toll gate of the highway, and has a curved road shape. It is determined (predicted) that the vehicle will re-accelerate after traveling at a reduced speed when information such as a change from a straight line to a straight line is obtained.

  If an affirmative determination is made in S402, the ECU 20 proceeds to S403, and calculates the electric power Epmotmax that can be supplied to the electric motor 106d. The electric power Epmotmax here is electric power required to increase the rotational speed of the motor assist turbo 54 to a rotational speed suitable for reacceleration. The amount of increase in the rotational speed of the motor assist turbo 54 correlates with the rotational speed of the motor assist turbo 54 or the flow rate of the exhaust gas flowing into the motor assist turbo 54. Therefore, a relationship between the electric power Epmotmax and the rotation speed (or exhaust flow rate) of the motor assist turbo 54 may be experimentally obtained in advance, and the relationship may be mapped.

  In S404, it is determined whether or not the power Epmotmax obtained in S403 is equal to or greater than the surplus generated power Epex. If an affirmative determination is made in S404 (Epmotmax ≧ Epex), the ECU 20 proceeds to S405 and controls the distributor 108 so that all of the surplus generated power Epex is supplied to the electric motor 106d.

  If a negative determination is made in S404 (Epmotmax <Epex), the ECU 20 proceeds to S406. In S406, the ECU 20 controls the distributor 108 such that the electric power corresponding to the electric power Epmotmax is supplied to the electric motor 106d and the remaining electric power is supplied to the other high-voltage electric load 106b. To do.

  If a negative determination is made in S402, the ECU 20 proceeds to S208 and controls the distributor 108 so that all of the surplus generated power Epex is distributed to the high voltage electric load 106b other than the electric motor 106d.

  As described above, when the ECU 20 executes the distribution control routine of FIG. 14, the surplus generated power Epex is preferentially supplied to the electric motor 106d, so that the drivability of the vehicle can be improved and the fuel consumption rate can be reduced. Improvement and reduction of exhaust emissions can be achieved. As a result, the kinetic energy regenerated by regenerative power generation can be used effectively.

<Example 5>
Next, a fifth embodiment of the present invention will be described with reference to FIG. Here, a configuration different from the above-described second embodiment will be described, and description of the same configuration will be omitted.

  The difference between the second embodiment described above and this embodiment is that the surplus generated power Epex is supplied to the low voltage battery 103 instead of being supplied to the high voltage electric load 106 such as an oil heater.

  The low voltage electric load 107 to which power is supplied from the low voltage battery 103 includes an electric load indispensable for the vehicle to travel, such as a fuel injection valve, a spark plug, a fuel pump, or an ECU 20. There is a case. Therefore, when the charging state of the low voltage battery 103 is lowered, it is desirable to charge the low voltage battery 103 in preference to the high voltage electric load 106.

  Therefore, when the alternator 101 performs regenerative power generation, if the state of charge of the low voltage battery 103 (measured value of the second SOC sensor 103a) is low, the ECU 20 reduces the surplus generated power Epex by the DC-DC converter 105. The low voltage battery 103 is supplied.

  When surplus generated power Epex is preferentially supplied to the low-voltage battery 103, avoiding a situation where the drive power of the low-voltage electric load 107 is insufficient or the operation of the low-voltage electric load 107 becomes unstable. Can do. Furthermore, it is possible to avoid a situation in which the surplus generated power Epex is discarded.

  Hereinafter, a procedure for distributing the surplus generated power Epex in the present embodiment will be described with reference to FIG. FIG. 15 is a flowchart showing a surplus generated power distribution control routine. This routine is a subroutine executed by the ECU 20 in S106 of the above-described regenerative power generation control routine (see FIG. 5). In FIG. 15, the same reference numerals are given to the processes equivalent to the distribution control routine (see FIG. 8) of the second embodiment described above.

  In the routine of FIG. 15, when an affirmative determination is made in S201, the ECU 20 proceeds to S501 and acquires the state of charge of the low-voltage battery 103 (measured value of the second SOC sensor 103a) SOC2.

  In S502, the ECU 20 determines whether or not the state of charge SOC2 acquired in S501 is equal to or lower than the lower limit value β. The lower limit value β is a value obtained by adding a predetermined margin to a minimum state of charge necessary for supplying power to the low-voltage electric load 107, and is determined in advance by an adaptation process using an experiment or the like.

  When an affirmative determination is made in S502 (SOC2 ≦ β), the ECU 20 proceeds to S503, and calculates the chargeable power Epbatsubmax of the low-voltage battery 103. The rechargeable power Epbatsubmax here is power necessary to increase the state of charge of the low-voltage battery 103 to the target value set higher than the lower limit value β.

  In step S504, the ECU 20 calculates the passing power of the DC-DC converter 105 (high voltage power stepped down by the DC-DC converter 105) Epdcdc. For example, the ECU 20 calculates the power when the chargeable power Epbatsubmax calculated in S503 is boosted to a high voltage.

In S505, the ECU 20 determines whether or not the passing power Epdcdc calculated in S504 is equal to or greater than the surplus generated power Epex. If an affirmative determination is made in S505 (Epdcdc ≧ Epex), the ECU 20 proceeds to S506 and controls the DC-DC converter 105 so that all of the surplus generated power Epex is supplied to the low voltage battery 103.

  If a negative determination is made in S505 (Epdcdc <Epex), the ECU 20 proceeds to S507. In S507, the ECU 20 supplies the DC-DC converter 105 so that the power corresponding to the above-described passing power Epdcdc is supplied to the low-voltage battery 103 and the remaining power is supplied to the high-voltage electric load 106b. And the distributor 108 is controlled.

  If a negative determination is made in S502, the ECU 20 proceeds to S508, and controls the distributor 108 so that all of the surplus generated power Epex is distributed to the high voltage electric load 106b.

  As described above, when the ECU 20 executes the distribution control routine of FIG. 15, the surplus generated power Epex is preferentially supplied to the low voltage battery 103, so that the low voltage electric load 107 that is indispensable for the vehicle to travel is included. Operation can be guaranteed.

  In addition, when the charging state of the low voltage battery 103 is low, the surplus generated power Epex may be supplied to the low voltage electric load 107 instead of being supplied to the low voltage battery 103, or the low voltage battery 103 and the low voltage electric load may be supplied. The surplus generated power Epex may be supplied to both of 107.

<Example 6>
Next, a sixth embodiment of the present invention will be described. Here, configurations different from those of the second to fifth embodiments described above will be described, and description of similar configurations will be omitted.

  In the second to fifth embodiments described above, any one of the oil heater 106a, the catalyst heating heater 106c, the motor assist turbo 54, or the low voltage battery 103 is mounted on the vehicle (or any one). In the present embodiment, the case where the surplus generated power Epex needs to be supplied to at least two of the plurality of electric devices will be described.

  When it is necessary to supply the surplus generated power Epex to at least two of the plurality of electric devices described above, the ECU 20 may determine a supply destination of the surplus generated power Epex according to a predetermined priority order. For example, the priority order may be set in the order of the low-voltage battery 103, the oil heater 106a, the catalyst heating heater 106c, and the motor assist turbo 54. In that case, the operation of the low-voltage electric load 107 that is indispensable for the traveling of the vehicle is ensured, and then the warm-up of the internal combustion engine 1 is promoted. In addition, if there is surplus generated power Epex that cannot be consumed by an electrical device with a high priority, it may be supplied to an electrical device with a low priority.

  Further, the ECU 20 may allocate the surplus generated power Epex to a plurality of electric devices by multiplying the surplus generated power Epex by a weighting coefficient previously assigned to each electric device.

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 2 Transmission 3 Propeller shaft 4 Differential gear 5 Drive shaft 6 Drive wheel 20 ECU
24 Crank position sensor 26 Oil temperature sensor 50 Exhaust passage 51 Exhaust purification catalyst 52 Catalyst temperature sensor 53 Intake passage 54 Motor assist turbo 54a Turbine 54b Compressor 100 Power generation mechanism 101 Alternator 101a Regulator 101b Temperature sensor 102 High voltage battery 102a First SOC sensor 103 Low voltage battery 103a Second SOC sensor 104 Changeover switch 105 DC-DC converter 106 High voltage electric load 106a Oil heater 106b High voltage electric load 106c Heater 106d for catalyst heating Electric motor 107 Low voltage electric load 108 Distributor

Claims (5)

In a regenerative power generation control system for a vehicle that performs regenerative power generation by operating a generator using the kinetic energy of the vehicle when the vehicle is in a decelerating running state,
A battery for storing electric power regenerated by the generator;
An acquisition means for acquiring a reference charging state that is a charging state of the battery when the power that the battery can accept is maximized;
When the vehicle is in a deceleration state, assuming that the state of charge of the previous SL battery is in the reference charge state, the maximum power equivalent to power the battery can accept a reference charge state to the generator and control means for power generation,
A regenerative power generation control system for a vehicle. According to claim 1, further comprising a calculating means for calculating the actual real chargeable power is actually power which can accept battery charge state as a parameter of the battery,
When the actual chargeable power calculated by the calculation means is smaller than the chargeable power in the reference charging state, the control means is an electric device in which surplus generated power that cannot be charged in the battery is mounted on the vehicle. A regenerative power generation control system for a vehicle, characterized by being supplied to a vehicle. In Claim 2, the electric device is a plurality of electric loads including a heat medium heater for heating the heat medium circulating in the internal combustion engine,
The regenerative power generation control system for a vehicle, wherein when the temperature of the heat medium is lower than an appropriate temperature, the control means supplies surplus generated power to the heat medium heater in preference to another electric load. In Claim 2, the electrical equipment is a plurality of electrical loads including a catalyst heater for heating an exhaust purification catalyst disposed in an exhaust passage of an internal combustion engine,
When the temperature of the exhaust purification catalyst is lower than the activation temperature, the control means supplies surplus generated power to the catalyst heater in preference to other electric loads, and the vehicle regenerative power generation control is characterized in that system. In Claim 2, the electric device is a sub-battery independent of the battery,
The regenerative power generation control system for a vehicle, wherein the control means supplies surplus generated power to the sub battery when the sub battery is in a chargeable state.

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