WO2011086657A1 - Control device and control method for hybrid vehicle - Google Patents

Abstract

Disclosed is a hybrid vehicle having an electrical heated catalyst (EHC), wherein, under the conditions that an engine (10) is not operated, the EHC is not activated, and electricity which can be discharged from a battery device is less than a predetermined value, an ECU temporarily increases a voltage command value (VH) so that electrical energy for assisting driving electricity of the EHC is temporarily stored in a smoothing capacitor, and the ECU lowers the voltage command value (VH) at the same time as the activation of the EHC is initiated so that the electrical energy temporarily stored in the smoothing capacitor is supplied to the EHC.

Description

Control device and control method for hybrid vehicle

This invention relates to control of a hybrid vehicle, and more particularly to control of a hybrid vehicle equipped with an electrically heated catalyst.

A vehicle equipped with an internal combustion engine is generally provided with a catalyst for purifying exhaust gas of the internal combustion engine. If the catalyst does not reach the activation temperature, the exhaust cannot be sufficiently purified. Therefore, conventionally, an electrically heated catalyst (hereinafter referred to as “EHC”) configured to be able to heat the catalyst with an electric heater or the like has been proposed.

Regarding a vehicle equipped with an EHC, Japanese Patent Application Laid-Open No. 5-187225 (Patent Document 1) discloses a technique for ensuring engine start by making an engine control power supply and an EHC power supply independent. Yes.

Further, in Japanese Patent Laid-Open No. 10-288028 (Patent Document 2), in a hybrid vehicle equipped with an EHC, if the state of charge of the battery is a state where the EHC cannot be sufficiently warmed up, the charge state of the battery is A technique is disclosed in which the exhausted state is suppressed while the battery exhaustion is suppressed by integrally controlling the operating state of the internal combustion engine and the energization amount to the EHC so that the EHC can be efficiently heated.

Japanese Laid-Open Patent Publication No. 6-58140 (Patent Document 3) discloses that in a vehicle equipped with an EHC, the voltage from a battery power source is boosted by a DC / DC converter and applied to an electric double layer capacitor. A technique for charging a capacitor and supplying electric power stored in an electric double layer capacitor to an EHC is disclosed.

JP-A-5-187225 Japanese Patent Laid-Open No. 10-288028 JP-A-6-58140

However, in any of Patent Documents 1 to 3 described above, when the battery temperature is lowered and the dischargeable power of the battery is limited, the EHC may not be sufficiently warmed up.

The present invention has been made in order to solve the above-described problems, and an object of the present invention is to reduce the electric power that can be discharged from a power storage device by reducing the temperature of the power storage device in a hybrid vehicle equipped with EHC. It is to warm up the EHC reliably.

The control device according to the present invention controls a hybrid vehicle. The hybrid vehicle includes an internal combustion engine, an electric motor, a first power storage device that stores electrical energy for driving the motor, a second power storage device, and the first power storage device and the second power storage device. A voltage conversion device that performs voltage conversion, a catalyst device that is configured to be electrically heated and that purifies exhaust gas of an internal combustion engine, and a first power storage device that is connected in parallel to the voltage conversion device and heats the catalyst device A power supply device capable of adjusting the power for the power supply. The control device determines whether or not the temperature of the first power storage device is lower than a predetermined temperature. When the temperature of the first power storage device is lower than the predetermined temperature, the control device stores the first power storage device in the first power storage device. When the first control for temporarily storing the stored electric energy in the second power storage device is executed and the catalyst device is operated, the second power storage device is controlled by the first control in addition to the electrical energy of the first power storage device. And a control unit that controls the voltage converter so as to execute the second control for supplying the temporarily stored electric energy to the power supply device.

Preferably, the voltage conversion device converts the voltage of the first power storage device into a value corresponding to the voltage command value and outputs the value to the second power storage device. When the temperature of the first power storage device is lower than the predetermined temperature, the control unit executes the first control by increasing the voltage command value, and decreases the voltage command value when operating the catalyst device. Execute control.

Preferably, the electric motor and the voltage conversion device are connected by power supply wiring and ground wiring. The second power storage device is a capacitor that smoothes the voltage between the power supply wiring and the ground wiring. The voltage conversion device is a boost converter that boosts the voltage of the first power storage device and outputs the boosted voltage to a capacitor.

Preferably, the second power storage device is an auxiliary battery that stores electric energy for operating an electric device mounted on the hybrid vehicle. The voltage conversion device is a step-down converter that steps down the voltage of the first power storage device and outputs it to the auxiliary battery.

Preferably, the control unit has a first condition that the internal combustion engine is stopped, a second condition that power supply to the catalyst device is stopped, and a first condition that the temperature of the first power storage device is lower than a predetermined temperature. The first control is executed when any of the three conditions is satisfied.

Preferably, the control unit limits the output power of the first power storage device when the temperature of the first power storage device is lower than a predetermined temperature.

A control method according to another aspect of the present invention is a control method performed by a hybrid vehicle control device. The hybrid vehicle includes an internal combustion engine, an electric motor, a first power storage device that stores electrical energy for driving the motor, a second power storage device, and the first power storage device and the second power storage device. A voltage conversion device that performs voltage conversion, a catalyst device that is configured to be electrically heated and that purifies exhaust gas of an internal combustion engine, and a first power storage device that is connected in parallel to the voltage conversion device and heats the catalyst device A power supply device capable of adjusting the power for the power supply. The control method includes a step of determining whether or not the temperature of the first power storage device is lower than a predetermined temperature, and when the temperature of the first power storage device is lower than the predetermined temperature, the temperature is stored in the first power storage device When the first control for temporarily storing the electrical energy in the second power storage device is executed and the catalyst device is operated, the first control temporarily stores the electrical energy in the second power storage device in addition to the electrical energy of the first power storage device. Controlling the voltage converter so as to perform a second control for supplying the stored electrical energy to the power supply device.

According to the present invention, in a hybrid vehicle equipped with an EHC, the EHC can be reliably warmed up even if the temperature of the power storage device decreases and the dischargeable power of the power storage device is limited.

1 is an overall block diagram of a hybrid vehicle. It is a flowchart (the 1) which shows the process sequence of ECU. It is a functional block diagram (the 1) of ECU. It is a figure which shows the correspondence of dischargeable electric power Wout, temperature Tb, and additional voltage value VHehc. It is a flowchart (the 2) which shows the process sequence of ECU. It is a timing chart of voltage VH. It is a figure which shows the flow of electrical energy. It is a functional block diagram (the 2) of ECU. It is a flowchart (the 3) which shows the process sequence of ECU.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

[First embodiment]
FIG. 1 is an overall block diagram of a hybrid vehicle according to an embodiment of the present invention. Referring to FIG. 1, hybrid vehicle 1 includes an engine 10, a first MG (Motor Generator) 20, a second MG 30, a power split device 40, a speed reducer 50, and drive wheels 80.

The engine 10 is an internal combustion engine that generates a driving force for rotating a crankshaft by combustion energy generated when an air-fuel mixture sucked into a combustion chamber is combusted.

The first MG 20 and the second MG 30 are AC motors, for example, three-phase AC synchronous motors.

Hybrid vehicle 1 travels by driving force output from at least one of engine 10 and second MG 30. The driving force generated by the engine 10 is divided into two paths by the power split device 40. That is, one is a path that is transmitted to the drive wheels 80 via the speed reducer 50, and the other is a path that is transmitted to the first MG 20.

The power split device 40 includes a planetary gear including a sun gear, a pinion gear, a carrier, and a ring gear. The pinion gear engages with the sun gear and the ring gear. The carrier supports the pinion gear so as to be capable of rotating, and is connected to the crankshaft of the engine 10. The sun gear is connected to the rotation shaft of the first MG 20. The ring gear is connected to the rotation shaft of second MG 30 and speed reducer 50.

Furthermore, the hybrid vehicle 1 includes a motor drive device 60, a smoothing capacitor C1, a voltage conversion device 90, and a power storage device 70.

The motor drive device 60 includes a first inverter 60-1 and a second inverter 60-2. First inverter 60-1 and second inverter 60-2 are connected to voltage converter 90 in parallel with each other.

The first inverter 60-1 is provided between the voltage converter 90 and the first MG 20. The first inverter 60-1 controls the drive of the first MG 20 based on a control signal S1 from an electronic control unit (Electronic Control Unit, hereinafter referred to as “ECU”) 150.

The second inverter 60-2 is provided between the voltage converter 90 and the second MG 30. Second inverter 60-2 controls driving of second MG 30 based on control signal S2 from ECU 150.

The power storage device 70 typically includes a DC secondary battery such as nickel metal hydride or lithium ion. Voltage Vb of power storage device 70 is, for example, about 280 volts. Dischargeable power Wout (unit: watts) of power storage device 70 decreases as temperature Tb of power storage device 70 decreases. Note that when power that exceeds dischargeable power Wout is output from power storage device 70 (when an excessive load is applied to power storage device 70), the life of power storage device 70 is shortened. Therefore, the output power of power storage device 70 is limited as the temperature Tb of power storage device 70 is lower. Specifically, ECU 150 calculates dischargeable power Wout based on temperature Tb of power storage device 70 and controls voltage conversion device 90 so that the discharge power of power storage device 70 is equal to or lower than dischargeable power Wout.

The first MG 20 generates power using the power of the engine 10 divided by the power split device 40. The electric power generated by first MG 20 is converted from alternating current to direct current by motor drive device 60 and stored in power storage device 70.

Second MG 30 generates driving force using at least one of the electric power stored in power storage device 70 and the electric power generated by first MG 20. Then, the driving force of the second MG 30 is transmitted to the driving wheels 80 via the speed reducer 50. In FIG. 1, the driving wheel 80 is shown as a front wheel, but the rear wheel may be driven by the second MG 30 instead of or together with the front wheel.

When the vehicle is braked, the second MG 30 is driven by the drive wheels 80 via the speed reducer 50, and the second MG 30 operates as a generator. Thereby, 2nd MG30 functions also as a regenerative brake which converts kinetic energy of vehicles into electric power. The electric power generated by second MG 30 is stored in power storage device 70.

The voltage conversion device 90 performs voltage conversion between the power storage device 70 and the motor driving device 60. Voltage conversion device 90 supplies voltage Vb of power storage device 70 (more precisely, voltage VL between power supply line PL0 and ground wiring GL0 closer to power storage device 70 than voltage conversion device 90) to control signal S3 from ECU 150. The voltage is boosted to the voltage command value indicated by and is output to the motor drive device 60. As a result, the voltage (hereinafter also referred to as “voltage VH of the power supply wiring PL1” or simply “voltage VH”) between the power supply wiring PL1 and the ground wiring GL0 closer to the motor drive device 60 than the voltage conversion device 90 is supplied to the control signal S3. Is controlled to a voltage command value indicated by

The smoothing capacitor C1 is connected between the power supply wiring PL1 and the ground wiring GL1. The smoothing capacitor C1 smoothes the voltage VH by storing electric charge according to the voltage VH.

The exhaust gas discharged from the engine 10 is discharged to the atmosphere through the exhaust passage 130. An EHC 140 is provided in the middle of the exhaust passage 130.

The EHC 140 is configured such that a catalyst for purifying exhaust gas can be electrically heated. The EHC 140 is connected to the EHC power source 100 and heats the catalyst with the power supplied from the EHC power source 100. Various known EHCs can be applied to the EHC 140.

The EHC power supply 100 is provided between the EHC 140 and the power storage device 70. EHC power supply 100 is connected to power storage device 70 in parallel with voltage conversion device 90. The EHC power supply 100 adjusts the driving power of the EHC 140 based on the control signal S5 from the ECU 150.

Furthermore, the hybrid vehicle 1 includes a DC / DC converter 190 and an auxiliary battery B.

The auxiliary battery B stores electric power for operating electric components (for example, ECU 150) mounted on the hybrid vehicle 1 and supplies the electric power to each electric device as necessary. The voltage Vd of the auxiliary battery B is, for example, about 12 volts and is lower than the voltage Vb of the power storage device 70.

DC / DC converter 190 is provided between auxiliary battery B and power storage device 70. DC / DC converter 190 is connected to power storage device 70 in parallel with voltage conversion device 90 and EHC power supply 100. DC / DC converter 190 steps down voltage Vb of power storage device 70 based on control signal S6 from ECU 150 and supplies the voltage to auxiliary battery B. DC / DC converter 190 boosts voltage Vd of auxiliary battery B based on control signal S6 from ECU 150, and supplies the boosted voltage to power supply line PL0.

Furthermore, the hybrid vehicle 1 is a so-called plug-in hybrid vehicle, and includes a charging port 160 and a charger 170 for charging the power storage device 70 with electric power from the external power supply 210.

The charging port 160 is a power interface for receiving power from the external power source 210. When charging power storage device 70 from external power supply 210, charging port 160 is connected to connector 200 of a charging cable for supplying power from external power supply 210 to the vehicle.

Charger 170 is electrically connected to charging port 160 and power storage device 70. Then, in the charging mode in which power storage device 70 is charged from external power supply 210, charger 170 converts the power supplied from external power supply 210 to the voltage level of power storage device 70 based on control signal S7 from ECU 150. The power storage device 70 is charged after conversion.

The hybrid vehicle 1 further includes temperature sensors 121 and 125, voltage sensors 122, 124, and 128, a current sensor 123, an accelerator pedal position sensor 126, and a navigation device 127.

The temperature sensor 121 detects the temperature Tb of the power storage device 70. Voltage sensor 122 detects voltage Vb of power storage device 70. Current sensor 123 detects current Ib flowing through power supply line PL0. Voltage sensor 124 detects voltage VH of power supply wiring PL1. The temperature sensor 125 detects the temperature Tehc of the EHC 140. The accelerator pedal position sensor 126 detects an accelerator pedal operation amount A by the user. Voltage sensor 128 detects voltage Vb of auxiliary battery B. Each of these sensors transmits a detection result to ECU 150.

The navigation device 127 calculates the travel prediction route information N of the hybrid vehicle 1 based on the destination set by the user and transmits it to the ECU 150.

The ECU 150 includes a CPU (Central Processing Unit) (not shown) and a memory, and is configured to execute predetermined arithmetic processing based on a map and a program stored in the memory. Alternatively, at least a part of the ECU 150 may be configured to execute predetermined numerical / logical operation processing by hardware such as an electronic circuit.

The ECU 150 generates the control signals S1 to S7 described above based on the information of each sensor and the like, and outputs the generated control signals S1 to S7 to each device.

FIG. 2 is a flowchart showing a processing procedure when the ECU 150 executes drive control of the EHC 140.

As shown in FIG. 2, at step 10 (hereinafter, “step” is abbreviated as “S”), ECU 150 makes an engine start request while engine 10 is stopped (when traveling at the output of second MG 30). Determine whether or not. ECU 150 determines that there is an engine start request, for example, when accelerator pedal operation amount A increases and it becomes impossible to generate the driving force requested by the user only with the output of second MG 30.

When ECU 150 determines that there is an engine start request (YES in S10), ECU 150 determines whether or not temperature Tehc of EHC 140 is lower than predetermined temperature T0 (S11).

When temperature Tehc of EHC 140 is higher than predetermined temperature T0 (NO in S11), ECU 150 determines that the purification performance of EHC 140 is higher than the target level, and starts engine 10 without driving EHC 140 (S13). ).

On the other hand, when temperature Tehc of EHC 140 is lower than predetermined temperature T0 (YES in S11), ECU 150 determines that the purification performance of EHC 140 is lower than the target level, and drives EHC 140 in preparation for starting of engine 10. (S12). Specifically, ECU 150 controls EHC power supply 100 to supply electric power from power storage device 70 to EHC 140 until temperature Tehc of EHC 140 reaches temperature T1 higher than predetermined temperature T0. Thereby, since the EHC 140 is heated, the purification performance is improved. Note that, in the so-called plug-in type hybrid vehicle as in the hybrid vehicle 1 of the present embodiment, the frequency of operation of the engine 10 is less than that of a normal hybrid vehicle, and the frequency Tehc of the EHC 140 is lower than the predetermined temperature T0. Therefore, there is a high need for such catalyst warm-up.

Then, the ECU 150 determines when the purification performance of the EHC 140 is predicted to reach the target level (for example, when it is detected that the temperature Tehc of the EHC 140 has reached a predetermined temperature T0, or when the driving time of the EHC 140 is a predetermined time). The engine 10 is started at the time of reaching (S13).

Thus, when the temperature Tehc of the EHC 140 is lower than the predetermined temperature T0, the ECU 150 drives the EHC 140 and warms up the EHC 140 in advance before starting the engine.

However, when the temperature is low, the temperature Tb of the power storage device 70 also decreases, and the dischargeable power Wout of the power storage device 70 is limited. Therefore, there is a case where the drive power of the EHC 140 is insufficient and the EHC 140 cannot be sufficiently warmed. .

In order to solve such a problem, the ECU 150 performs control (hereinafter also referred to as “buffer control”) for stably supplying power to the EHC 140 even at a low temperature. Specifically, the ECU 150 temporarily stores more electric energy than usual in the smoothing capacitor C1 in preparation for driving the EHC 140 when the dischargeable power Wout is low, such as at low temperatures, and then drives the EHC 140. The electric energy temporarily stored in the smoothing capacitor C1 is sometimes supplied to the EHC power supply 100 to assist the drive power of the EHC 140. This is the most characteristic point of this embodiment.

FIG. 3 is a functional block diagram of the ECU 150 relating to the buffer control described above. Note that each functional block shown in FIG. 3 may be realized by providing the ECU 150 with hardware (electronic circuit or the like) having the function, or software processing (execution of a program or the like) corresponding to the function. May be realized by causing the ECU 150 to perform the above.

3, the ECU 150 includes an additional voltage setting unit 151, an addition unit 152, an upper limiter 153, a change rate filter 154, and a generation unit 155.

The additional voltage setting unit 151 sets an additional voltage value VHehc with respect to the required voltage value VHsys and outputs the additional voltage value VHehc to the adding unit 152. Here, required voltage value VHsys is a required value for voltage VH of power supply wiring PL1, and is set by, for example, an external ECU (not shown). The additional voltage value VHehc is a voltage that is added to the required voltage value VHsys in order to temporarily store electric energy for assisting the driving power of the EHC 140 in the smoothing capacitor C1. The additional voltage setting unit 151 includes a determination unit 151A and a setting unit 151B.

The determination unit 151A determines whether the following first to third conditions are satisfied or not, and outputs the determination results to the setting unit 151B.

The first condition is a condition that the engine 10 is in operation. The success or failure of the first condition is determined based on, for example, the control signal S4.

The second condition is a condition that the EHC 140 is operating. The success or failure of the second condition is determined based on the control signal S5, for example.

The third condition is a condition that the dischargeable power Wout of the power storage device 70 is larger than the predetermined value W1. The predetermined value W1 is electric power (unit: watts) required for driving the EHC 140. The success or failure of the third condition is performed based on the temperature Tb of the power storage device 70. Note that the success or failure of the third condition may be determined using another parameter instead of or in addition to the temperature Tb.

When the first condition is satisfied or the second condition is satisfied, the setting unit 151B temporarily stores electric energy for assisting the driving power of the EHC 140 in the smoothing capacitor C1. The additional voltage value VHehc is set to “0”.

On the other hand, when both of the first and second conditions are not satisfied, setting unit 151B adds according to whether the third condition is satisfied (that is, whether dischargeable power Wout is greater than predetermined value W1). A voltage value VHehc is set. When Wout> W1, setting unit 151B determines that the drive power of EHC 140 is secured, and sets additional voltage value VHehc to “0”. On the other hand, when Wout <W1, the setting unit 151B determines that the drive power of the EHC 140 is insufficient, and sets the additional voltage value VHehc to “A (> 0)”.

FIG. 4 is a diagram illustrating a correspondence relationship between the dischargeable power Wout of the power storage device 70, the temperature Tb of the power storage device 70, and the additional voltage value VHehc set by the additional voltage setting unit 151. As shown in FIG. 4, when the dischargeable power Wout when the temperature Tb is the predetermined temperature T1 is the predetermined value W1, the additional voltage value VHehc is “0” because Wout> W1 in the range of Tb> T1. In the range of Tb <T1, Wout <W1, so that the additional voltage value VHehc is set to “A”.

Returning to FIG. 3, the adding unit 152 sets a value obtained by adding the additional voltage value VHehc input from the additional voltage setting unit 151 to the voltage request value VHsys input from the external ECU, as a voltage command value VH0, and the upper limiter 153. Output to.

The upper limiter 153 sets a value obtained by limiting the upper limit value of the voltage command value VH0 to the maximum boosted voltage value VHmax as the voltage command value VH1, and outputs it to the change rate filter 154. More specifically, the upper limiter 153 sets VH1 = VL when VH0 <VL, sets VH1 = VH0 when VL <VH0 <VHmax, and sets VH1 = VHmax when VHmax <VH0. To do.

The change rate filter 154 sets a value obtained by limiting the amount of change per unit time of the voltage command value VH1 by a predetermined calculation process as the voltage command value VHcom, and outputs the voltage command value VHcom to the generation unit 155.

The generation unit 155 generates a control signal S4 for controlling the voltage VH to a value corresponding to the voltage command value VHcom, and outputs the control signal S4 to the voltage converter 90.

FIG. 5 is a flowchart showing a control processing procedure of the ECU 150 for realizing the function of the additional voltage setting unit 151 shown in FIG.

In S20, ECU 150 determines whether or not the first condition described above is satisfied, that is, whether or not engine 10 is in operation. If engine 10 is in operation (YES in S20), the process proceeds to S24. Otherwise (NO at S0), the process proceeds to S1.

In S21, ECU 150 determines whether or not the second condition described above is satisfied, that is, whether or not EHC 140 is operating. If EHC 140 is in operation (YES in S21), the process proceeds to S24. Otherwise (NO in S21), the process proceeds to S22.

In S22, ECU 150 determines whether or not the above-described third condition is satisfied, that is, whether or not dischargeable power Wout is greater than predetermined value W1. If dischargeable power Wout is greater than predetermined value W1 (YES in S22), the process proceeds to S24. Otherwise (NO in S22), the process proceeds to S23.

In S23, ECU 150 sets additional voltage value VHehc to “A”. In S24, ECU 150 sets additional voltage value VHehc to “0”.

FIG. 6 is a timing chart of the voltage VH when the ECU 150 performs buffer control. FIG. 7 is a diagram showing a flow of electric energy by buffer control.

When the dischargeable power Wout falls below the predetermined value W1 at time t1, the additional voltage value VHehc is set to “A” in preparation for the subsequent driving of the EHC 140. Thereby, as shown in the period α in FIG. 6, the voltage VH is temporarily controlled to a value higher than the voltage request value VHsys by an additional voltage value VHehc (= A). That is, as indicated by an arrow α in FIG. 7, the electrical energy stored in the power storage device 70 is temporarily stored in the smoothing capacitor C1 by an amount corresponding to the additional voltage value VHehc.

At the same time t2, the operation of the EHC 140 is started, and at the same time, the additional voltage value VHehc is set to “0”. As a result, the voltage VH gradually decreases to the required voltage value VHsys as shown in the period β of FIG. That is, as shown by an arrow β in FIG. 7, an amount of electrical energy corresponding to the additional voltage value VHehc temporarily stored in the smoothing capacitor C1 is supplied to the EHC power supply 100 (ie, EHC 140).

As described above, in this embodiment, when the dischargeable power Wout of the power storage device 70 decreases at a low temperature, the voltage VH is increased from the normal value in preparation for the subsequent drive of the EHC 140, so that the smoothing capacitor C1 normally More electrical energy is temporarily stored, and when the EHC 140 is driven, the voltage VH is lowered to a normal value, whereby the electrical energy temporarily stored in the smoothing capacitor C1 is supplied to the EHC power source 100, and the EHC 140 Assist the drive power.

Therefore, even when the temperature Tb of the power storage device 70 decreases and the dischargeable power Wout of the power storage device 70 is limited, sufficient power can be stably supplied to the EHC 140 without applying an excessive load to the power storage device 70. it can. Therefore, it is possible to reliably warm up the EHC and improve the exhaust gas purification performance while prolonging the life of the power storage device 70. Moreover, since the existing smoothing capacitor C1 and the voltage conversion device 90 are used, it is not necessary to increase the capacity of the power storage device 70 or add parts, and the cost can be suppressed.

In this embodiment, when all the first to third conditions are satisfied (that is, when the engine 10 is stopped and the EHC 140 is stopped and it is determined that Wout <W1), the engine 10 is turned off. The additional voltage value VHehc is set to “A” regardless of whether or not it is necessary to start the engine. For example, when all the first to third conditions are satisfied, it is necessary to start the engine 10 in the near future. When it is predicted that the engine 10 needs to be started in the near future, the additional voltage value VHehc may be set to “A”. Whether or not it is necessary to start the engine 10 in the near future depends on, for example, the remaining capacity of the power storage device 70 and the predicted travel route information N from the navigation device 127 (whether or not the hybrid vehicle 1 starts traveling on a long uphill. ) Based on this.

Further, in this embodiment, the series / parallel type hybrid vehicle in which the power of the engine 10 is divided by the power split device 40 and can be transmitted to the drive wheels 80 and the first MG 20 has been described. The present invention can also be applied to a so-called parallel type hybrid vehicle in which wheels are driven by an engine and a motor without being provided, or a so-called series type hybrid vehicle in which wheels are driven by a motor using the engine only for power generation.

In the present embodiment, the present invention is applied to a so-called plug-in type hybrid vehicle. However, the present invention is not limited to this, and the present invention may be applied to an ordinary hybrid vehicle.

[Second Embodiment]
In the first embodiment, a case has been described in which the electrical energy of the power storage device 70 is temporarily stored in the smoothing capacitor C1 in order to stably supply power to the EHC 140 even at a low temperature.

On the other hand, in the second embodiment, the electrical energy of the power storage device 70 is temporarily stored in the auxiliary battery B instead of the smoothing capacitor C1 or in addition to the smoothing capacitor C1. Since other structures, functions, and processes are the same as those in the first embodiment, detailed description thereof will not be repeated here.

FIG. 8 is a functional block diagram of a portion related to buffer control of the ECU 150A according to the second embodiment.

As shown in FIG. 8, the ECU 150A includes an additional voltage setting unit 156, an adding unit 157, and a generating unit 158.

The additional voltage setting unit 156 sets the additional voltage value Vdehc with respect to the required voltage value Vdsys, and outputs it to the adding unit 157. . Here, the required voltage value Vdsys is a required value for the voltage Vd of the auxiliary battery B, and is set by, for example, an external ECU (not shown). The additional voltage value Vdehc is a voltage that is added to the required voltage value Vdsys.

The additional voltage setting unit 156 includes a determination unit 156A and a setting unit 156B. Note that the function of determination unit 156A is the same as that of determination unit 151A shown in FIG. 3, and therefore detailed description thereof will not be repeated.

The setting unit 156B receives the determination result of the determination unit 156A, and when the first condition is satisfied (when the engine 10 is in operation) or when the second condition is satisfied (EHC 140 is If it is in operation), it is determined that there is no need to temporarily store electric energy for assisting the drive power of EHC 140 in auxiliary battery B, and additional voltage value Vdehc is set to “0”.

On the other hand, when both the first and second conditions are not satisfied, setting unit 156B adds according to whether or not the third condition is satisfied (that is, whether or not dischargeable power Wout is greater than predetermined value W1). A voltage value Vdehc is set. When Wout> W1, the setting unit 156B determines that the drive power of the EHC 140 is secured, and sets the additional voltage value Vdehc to “0”. On the other hand, when Wout <W1, the setting unit 156B determines that the drive power of the EHC 140 is insufficient, and sets the additional voltage value Vdehc to “B (> 0)”.

The addition unit 157 outputs a value obtained by adding the additional voltage value Vdehc input from the additional voltage setting unit 156 to the voltage request value Vdsys input from the external ECU to the generation unit 158 as the voltage command value Vdcom.

The generation unit 158 generates a control signal S6 for controlling the voltage Vd of the auxiliary battery B to a value corresponding to the voltage command value Vdcom, and outputs the control signal S6 to the DC / DC converter 190.

FIG. 9 is a flowchart showing a control processing procedure of the ECU 150A for realizing the function of the additional voltage setting unit 156 shown in FIG. In the flowchart shown in FIG. 9, the same steps as those in the flowchart shown in FIG. 5 are given the same step numbers. The processing is the same for them. Therefore, detailed description thereof will not be repeated here.

As shown in FIG. 9, when a negative determination is made in all the processes of S20, S21, and S22, ECU 150A sets additional voltage value Vdehc to “B” in S30. On the other hand, if an affirmative determination is made in at least one of S20, S21, and S22, ECU 150A sets additional voltage value Vdehc to “0” in S31.

As described above, in this embodiment, when the dischargeable power Wout of the power storage device 70 decreases at a low temperature, the voltage Vd of the auxiliary battery B is increased from the normal value in preparation for the subsequent driving of the EHC 140. The auxiliary battery B temporarily stores more electrical energy than usual, and then temporarily stores the auxiliary battery B in the auxiliary battery B by lowering the voltage Vd of the auxiliary battery B to the normal value when the EHC 140 is driven thereafter. Electric energy is supplied to the EHC power supply 100 to assist the drive power of the EHC 140.

Therefore, as in the first embodiment, sufficient power can be stably supplied to the EHC 140 without applying an excessive load to the power storage device 70 even at a low temperature. Gas purification performance can be improved. Further, since the existing auxiliary battery B and the DC / DC converter 190 are used, it is not necessary to increase the capacity of the power storage device 70 or add parts, and the cost can be suppressed.

In the first and second embodiments described above, the case where the electrical energy of the power storage device 70 is temporarily stored in the other power storage device (smoothing capacitor C1 or auxiliary battery B) as the electrical energy has been described. The electrical energy of power storage device 70 may be temporarily stored in a state of being converted to another energy form. For example, by using the electrical energy of power storage device 70 to temporarily maintain the rotational speed of first MG 20 or second MG 30 higher than normal, the electrical energy of power storage device 70 is converted to the kinetic energy (rotational energy of first MG 20 or second MG 30). ) Can be temporarily stored in a converted state. In this case, when the operation of the EHC 140 is started, the regenerative power generated by the first MG 20 or the second MG 30 by the inertial force of the first MG 20 or the second MG 30 is supplied to the EHC power source 100 (that is, the EHC 140). Good.

The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 hybrid vehicle, 10 engine, 20 1st MG, 30 2nd MG, 40 power split device, 50 speed reducer, 60 motor drive device, 60-1 first inverter, 60-2 second inverter, 70 power storage device, 80 drive wheels , 90 voltage converter, 100 EHC power supply, 121, 125 temperature sensor, 122, 124, 128 voltage sensor, 123 current sensor, 126 accelerator pedal position sensor, 127 navigation device, 130 exhaust passage, 140 EHC, 150 ECU, 151 156 Additional voltage setting unit, 151A, 156A determination unit, 151B, 156B setting unit, 152, 157 addition unit, 153 upper limit limiter, 154 change rate filter, 155, 158 generation unit, 160 charging port, 170 charger 190 DC / DC converter, 200 connector, 210 external power supply, B auxiliary battery, C1 smoothing capacitor, GL0, GL1 ground line, PL0, PL1 power wiring.

Claims (7)

A control device for a hybrid vehicle,
The hybrid vehicle
An internal combustion engine (10);
An electric motor (30);
A first power storage device (70) for storing electrical energy for driving the electric motor;
A second power storage device (C1, B);
A voltage converter (90, 190) for performing voltage conversion between the first power storage device and the second power storage device;
A catalyst device (140) configured to be electrically heated and purifying exhaust gas of the internal combustion engine;
A power supply device (100) connected in parallel to the voltage conversion device with respect to the first power storage device and capable of adjusting power for heating the catalyst device;
The control device includes:
A determination unit (151A) for determining whether the temperature of the first power storage device is lower than a predetermined temperature;
When the temperature of the first power storage device is lower than the predetermined temperature, the first control for temporarily storing the electrical energy stored in the first power storage device in the second power storage device is executed, and the catalyst When operating the device, in addition to the electrical energy of the first power storage device, the second control is executed to supply the power source device with the electrical energy temporarily stored in the second power storage device by the first control. A control device for a hybrid vehicle, including a control unit (150) for controlling the voltage conversion device. The voltage conversion device converts the voltage of the first power storage device into a value corresponding to a voltage command value and outputs the value to the second power storage device,
The controller performs the first control by increasing the voltage command value when the temperature of the first power storage device is lower than the predetermined temperature, and the voltage command value when operating the catalyst device. The control apparatus for a hybrid vehicle according to claim 1, wherein the second control is executed by lowering the value. The electric motor and the voltage converter are connected by a power supply wiring (PL1) and a ground wiring (GL1),
The second power storage device is a capacitor (C1) that smoothes a voltage between the power supply wiring and the ground wiring,
The hybrid vehicle control device according to claim 2, wherein the voltage conversion device is a boost converter (90) that boosts the voltage of the first power storage device and outputs the boosted voltage to the capacitor. The second power storage device is an auxiliary battery (B) that stores electric energy for operating an electric device mounted on the hybrid vehicle,
The hybrid vehicle control device according to claim 2, wherein the voltage conversion device is a step-down converter (190) that steps down the voltage of the first power storage device and outputs the step-down voltage to the auxiliary battery. The control unit includes a first condition that the internal combustion engine is stopped, a second condition that power supply to the catalyst device is stopped, and a temperature of the first power storage device is lower than the predetermined temperature. The hybrid vehicle control device according to claim 2, wherein the first control is executed when any of the third conditions is established. The hybrid vehicle according to claim 1, wherein the control unit (151b) limits the output power of the first power storage device when the temperature of the first power storage device is lower than the predetermined temperature. Control device. A control method performed by a hybrid vehicle control device,
The hybrid vehicle
An internal combustion engine (10);
An electric motor (30);
A first power storage device (70) for storing electrical energy for driving the electric motor;
A second power storage device (C1, B);
A voltage converter (90, 190) for performing voltage conversion between the first power storage device and the second power storage device;
A catalyst device (140) configured to be electrically heated and purifying exhaust gas of the internal combustion engine;
A power supply device (100) connected in parallel to the voltage conversion device with respect to the first power storage device and capable of adjusting power for heating the catalyst device;
The control method is:
Determining whether the temperature of the first power storage device is lower than a predetermined temperature;
When the temperature of the first power storage device is lower than the predetermined temperature, the first control for temporarily storing the electrical energy stored in the first power storage device in the second power storage device is executed, and the catalyst When operating the device, in addition to the electrical energy of the first power storage device, the second control is executed to supply the power source device with the electrical energy temporarily stored in the second power storage device by the first control. A control method for a hybrid vehicle, comprising: controlling the voltage converter.

Images