JP2000156919A - Power supply apparatus for hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power supply apparatus for a hybrid vehicle, which can suppress the electrical energy of a capacitor for motor-generator drive from being consumed wastefully. SOLUTION: This power supply apparatus for a hybrid vehicle is provided with an engine which transmits a motive force to a wheel. It is provided with a motor generator which has a function for transmitting motive force to the wheel and which comprises a function to start the engine. It is provided with a capacitor which supplies electric power to the motor generator, an auxiliary battery which is installed separately from the capacitor and which supplies electric power to a starter motor, a DC/DC converter which transfers electric power between the capacitor and the auxiliary battery. In addition, it is provided with a power supply control means (Step 100 to Step 103) which supplies the electric power of the capacitor to the auxiliary battery, when a request for starting the engine is not generated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hybrid vehicle having an engine and a starter having a function of transmitting power to wheels and a function of starting the engine, and more particularly to a power supply for controlling a power supply of the starter. It is.

[0002]

2. Description of the Related Art Conventionally, a vehicle equipped with a motor generator (first starting device) as a second power source has been developed in addition to an internal combustion engine (engine) generally used as a driving force source of the vehicle. ing. In this type of vehicle, the power output by the motor generator is not always sufficient for the vehicle to travel, but the controllability of the output of the motor generator is good, and the regeneration of energy by the motor generator is required. What you can do
The generator is configured to use a motor / generator taking advantage of the advantage that no exhaust gas is generated.

For example, when a large torque is required at the time of starting or the like, the motor generator is operated as an auxiliary power source of the internal combustion engine, and at the time of deceleration, the motor generator is made to function as a generator to save energy. Control such as regeneration is performed. An example of a vehicle power supply adjustment circuit applied to the above-described hybrid vehicle is described in Japanese Patent Application Laid-Open No. 4-271209.

The power supply adjusting circuit for a vehicle includes an induction rotating machine (first starting device) connected to a main shaft of an internal combustion engine (engine), a capacitor (power supply for a starting device) serving as a power source of the induction rotating machine. A storage battery (power supply for a functional device) connected in parallel with the capacitor and serving as a power supply for an auxiliary device (functional device) of the vehicle; and a power supply between the induction rotating machine and the storage battery and / or the capacitor. An inverter circuit for performing conversion, first switch means connected in series to a storage battery, and second switch means connected in series to a capacitor are described. By controlling the opening and closing of the first and second switch means, power can be freely exchanged between the storage battery and the capacitor.

[0005]

By the way, in the power supply adjusting circuit described in the above-mentioned publication, when a state in which an engine start request is not generated is continued for a long time, the power is accumulated in the capacitor due to self-discharge of the capacitor. There is a problem that the used electric energy is wasted.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a power supply device for a hybrid vehicle that can suppress wasteful consumption of electric energy of a power supply for a starting device. .

[0007]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, an invention for transmitting power to wheels, a function for transmitting power to the wheels, and starting the engine are provided. A first starting device having a function of performing the following functions; a starting device power source for supplying power to the first starting device; and a starting device power source provided separately from the first starting device.
A power supply device for a hybrid vehicle having a power supply for a functional device that supplies power to a functional device of the vehicle, and a power supply circuit that enables transmission and reception of power between the power supply for the starting device and the power supply for the functional device. A power supply control means is provided for supplying the power of the power supply for the starting device to the power supply for the functional device when the request for starting the engine is not issued.

According to the first aspect of the present invention, the electric energy stored in the power supply for the starting device is charged to the power supply for the functional device under the condition that the request for starting the engine is not generated. Therefore, the electric energy stored in the power supply for the starting device is used as the electric energy for the functional device.

According to a second aspect of the present invention, in addition to the configuration of the first aspect, power is supplied from the power supply for the starting device to the power supply for the functional device during a period of less than a predetermined time after the start request of the engine is extinguished. And a power supply prohibition unit for prohibiting the power supply.

According to the second aspect of the invention, the same operation as in the first aspect is produced, and the electric energy of the power supply for the starting device is directly started under the condition that there is a possibility that the engine start request may be generated again. It is held by the device power supply.

According to a third aspect of the invention, in addition to the configuration of the first or second aspect, the functional device is provided separately from the first starting device and has a function of starting the engine. In the case where the voltage of the power supply for the starting device is equal to or higher than a predetermined value, the engine is started by the first starting device, and the voltage of the power supply for the starting device is lower than the predetermined value. In this case, an engine starting means for starting the engine by the second starting device is provided.

According to the third aspect of the present invention, the same operation as in the first or second aspect is produced, and under the condition where it is difficult to start the engine by the first starting device, the second starting device is used. The engine is started.

[0013]

Next, the present invention will be described more specifically with reference to the drawings. FIG. 2 is a skeleton diagram showing a schematic configuration of a hybrid vehicle to which the present invention is applied, and FIG. 3 is a circuit diagram showing a main part of FIG. The hybrid vehicle in this embodiment has an engine 1 having a function as a first driving force source of the vehicle, and a motor generator (MG) 2 having a function as a second driving force source of the vehicle. The motor / generator 2 is arranged on the output side of the engine 1. In addition, motor generator 2
A transmission (T / M) is provided in the power transmission path between the
4, a propeller shaft 5, a differential device 6, an axle shaft 7, and the like are arranged.

As the engine 1, an internal combustion engine such as a gasoline engine, a diesel engine or an LPG engine is used. The engine 1 has a known structure including a fuel injection device (not shown), a lubrication device (not shown), an ignition device (not shown), a cooling device (not shown), and the like. Further, a starter motor 8 having a function of starting the engine 1 is provided. As the starter motor 8, a known DC motor such as a magnetic shift type or a reduction gear type is used.
The torque output from the starter motor 8 is transmitted to a flywheel (not shown) of the engine 1 to start the engine 1, and the engine 1 autonomously rotates by fuel injection by a fuel injection device and ignition of an ignition device. I do.

An electronic throttle valve (not shown) is provided in an intake pipe of the engine 1 so that the opening of the electronic throttle valve is electrically controlled. As the motor generator 2, for example, an AC synchronous type is applied. Motor generator 2
A rotor (not shown) having a permanent magnet and a stator (not shown) around which a coil is wound are provided. When a three-phase alternating current flows through the three-phase winding of the coil, a rotating magnetic field is generated, and torque is generated by controlling the rotating magnetic field according to the rotation position and the rotation speed of the rotor. The torque generated by the motor generator 2 is substantially proportional to the magnitude of the current, and the rotation speed of the motor generator 2 is controlled by the frequency of the alternating current. And
The motor-generator 2 has a function as a motor for converting electric energy into mechanical energy and a function as a generator for converting mechanical energy into electric energy.

That is, the motive energy input from the wheels 3 is transmitted to the motor / generator 2 while the vehicle is running by transmitting the power of the motor / generator 2 to the wheels 3 while the vehicle is decelerating or braking. It is also possible to generate regenerative braking force (regenerative braking torque) by using the motor / generator 2 as a generator. It is also possible to start the engine 1 by transmitting the torque of the motor / generator 2 to the engine 1.

The transmission 4 includes a transmission capable of changing the gear ratio by manual operation or an automatic transmission capable of automatically controlling the gear ratio based on the running state of the vehicle. included. In this embodiment, an automatic transmission will be described as an example, hereinafter, referred to as an "automatic transmission 4". The automatic transmission 4 includes a plurality of planetary gear mechanisms (not shown), and a plurality of frictional engagement devices (not shown) engaged / disengaged for switching the torque transmission paths of these planetary gear mechanisms. It is of a known structure provided with By switching between the engaged and disengaged states of these friction engagement devices, the gear ratio (that is, the gear position) of the automatic transmission 4 is controlled.

A hydraulic control device 9 for controlling the automatic transmission 4 is provided. The hydraulic control device 9 controls the setting or switching of the gear position of the automatic transmission 4 and the hydraulic pressure acting on the friction engagement device. Control of the line pressure in the hydraulic circuit, control of the engagement pressure of the friction engagement device, and the like.
The hydraulic control device 9 is electrically controlled and includes various solenoid valves.

On the other hand, an inverter 11 is arranged in a circuit between the motor generator 2 and a capacitor 10 for supplying power to the motor generator 2. As shown in FIG. 3, the capacitor 10 has a plurality of capacitors (cells) 12 connected in series with each other, and a plurality of resistors 13 arranged in series with each other. A single module is constituted by the plurality of capacitors 12, and a plurality of modules are formed. In addition, each capacitor 12
And each resistor 13 are arranged in parallel with each other. These resistors 13 have a function of self-discharging the capacitor 10 and holding the voltage between the capacitors 12 equally. The rated voltage of the capacitor 10 thus configured is, for example, 2
It is set to 88V.

The inverter 11 converts the DC current of the capacitor 10 into a three-phase AC current and
And a three-phase bridge circuit (not shown) that converts a three-phase AC current generated by the motor generator 2 into a DC current and supplies the DC current to the capacitor 10. This three-phase bridge circuit is configured by electrically connecting, for example, six power transistors (not shown), and by switching on and off of these power transistors, the motor generator 2 and the capacitor 10 are connected to each other. Switch the direction of the current between them. In this way, the mutual conversion between the three-phase AC current and the DC current, the adjustment of the frequency of the three-phase AC current applied to the motor generator 2, and the conversion of the three-phase AC current applied to the motor generator 2 are performed. The adjustment of the magnitude and the magnitude of the regenerative braking torque of the motor / generator 2 are performed.

Further, a DCDC converter 14 is connected to the capacitor 10, and an auxiliary battery 15 is connected to the DCDC converter 14. This DCDC converter 14
Is a known device provided with a bridge circuit formed by a plurality of transistors, a transformer, a commutator, a smoothing capacitor, and the like. And this DCDC converter 14
It has a function of reducing the DC voltage of the capacitor 10 to a predetermined voltage and charging the auxiliary battery 15.

The auxiliary battery 15 is a known battery having an electrode plate, a separator, and the like. The auxiliary battery 15 can convert electrical energy into chemical energy and store it, and can extract it as electrical energy as needed. In particular,
The auxiliary machine battery 15 includes the starter motor 8 and the auxiliary machine 16
It also has a function of supplying power to various electronic control devices (described later). The auxiliary device 16 includes, for example, a vehicle headlamp (not shown), an air-conditioning blower or a fan (not shown), and the like. The rated voltage of the auxiliary battery 15 is set to, for example, 12V.

On the other hand, a hybrid electronic control unit (HV-ECU) 18 is connected to the capacitor 10 via a capacitor electronic control unit (capacitor ECU) 17, and an inverter 11 is connected to a motor / generator. The hybrid electronic control unit 18 is connected via an electronic control unit (motor ECU) 19. The electronic control unit 17 for the capacitor, the electronic control unit 18 for the hybrid, and the electronic control unit 19 for the motor / generator
Each is composed of a central processing unit (CPU), storage devices (RAM, ROM), and a microcomputer mainly including an input / output interface.

Then, the capacitor 10 and the capacitor electronic control unit 17 are connected to each other so as to be able to perform data communication,
The capacitor electronic control device 17 and the hybrid electronic control device 18 are connected so as to be able to perform data communication with each other. Further, the inverter 11 and the motor / generator electronic control device 19 are connected to each other so as to be able to perform data communication,
The motor / generator electronic control unit 19 and the hybrid electronic control unit 18 are connected so as to be able to perform data communication with each other.

The capacitor electronic control unit 17 detects the charge amount and voltage of the capacitor 10 and
It has a function of detecting a current value of a current flowing between the capacitor 10 and the motor generator 2. The motor / generator electronic control unit 19 has a function of controlling the motor / generator 2 via the inverter 11 based on a signal from the hybrid electronic control unit 18.

Further, the hybrid electronic control unit 18
, A transmission electronic control unit (T / M-ECU) 20
And an electronic control unit for engine (engine ECU) 21. The transmission electronic control device 20
And the engine electronic control unit 21 are respectively a central processing unit (CPU) and a storage device (RAM, RO
M) and a microcomputer mainly comprising an input / output interface. And
The hybrid electronic control unit 18, the transmission electronic control unit 20, and the engine electronic control unit 21 are connected so as to be able to perform data communication with each other.

For the engine electronic control unit 21, a signal of an ignition switch (not shown) for detecting the operation of an ignition key (not shown), the depression amount of an accelerator pedal (not shown), A signal from an accelerator opening sensor (not shown) for detecting the opening,
A signal of a cooling water temperature sensor (not shown) for detecting the temperature of the cooling water of the cooling device, a signal of an engine speed sensor, and the like are input to. And the signal of the accelerator opening sensor,
Based on a signal from the shift position sensor, a signal from the output shaft speed sensor, and the like, the torque of the engine 1, the gear ratio (gear position) of the automatic transmission 4, and the torque of the motor generator 2 are calculated, and the driving force of the vehicle is calculated. Controlled.

The electronic control unit 20 for the transmission includes a running state of the vehicle,
For example, a shift diagram using the vehicle speed and the accelerator opening as parameters is stored. This transmission electronic control unit 20
, A signal from a shift position sensor (not shown) for detecting a shift position of a shift device (not shown), a signal from an input shaft speed sensor of the automatic transmission 4, and an output shaft rotation of the automatic transmission 4. A signal from a number sensor, a signal from an accelerator opening sensor, and the like are input. Then, a control signal is output from the hybrid electronic control device 18 based on signals from the shift position sensor, the accelerator opening sensor, and the output shaft speed sensor. Based on this control signal, actuators such as various electromagnetic valves of the hydraulic control device 9 are controlled, or the gear ratio is controlled.

On the other hand, from the hybrid electronic control unit 18, the motor / generator 2 or the starter motor 8
, A control signal for turning on / off a power supply circuit between the starter motor 8 and the auxiliary battery 15, a drive signal / stop signal for the DCDC converter 14,
A drive / stop signal for the inverter 11 is output.

Here, the correspondence between the configuration of the hybrid vehicle and the configuration of the present invention will be described. That is, the motor generator 2 corresponds to the first starting device of the present invention, the capacitor 10 corresponds to the power supply for the starting device of the present invention, the DCDC converter 14 corresponds to the power supply circuit of the present invention, And the starter motor 8 corresponds to the functional device of the present invention. The auxiliary battery 15 corresponds to the power supply for the functional device of the present invention, and the starter motor 8 corresponds to the second starting device of the present invention.

The control contents of the hybrid vehicle having the above hardware configuration will be briefly described. That is, the necessary driving force is determined based on the accelerator opening, the vehicle speed, the shift position, and other conditions, and the output of the engine 1, the gear ratio of the automatic transmission 4, the torque of the motor generator 2, and the like are controlled. The power of at least one of the engine 1 and the motor generator 2 can be transmitted to the wheels 3 via the automatic transmission 4 and the propeller shaft 5. Further, only the power of the motor generator 2 can be transmitted to the wheels 3 via the automatic transmission 4 and the propeller shaft 5. When the charge amount of the capacitor 10 becomes equal to or less than a predetermined value, the engine 1
A part of the motive power is transmitted to the motor generator 2 to function as a generator, and the electric energy is
It is also possible to charge the battery.

On the other hand, at the time of deceleration of the vehicle, it is possible to generate an engine braking force by transmitting the kinetic energy input via the wheels 3 to the engine 1. By inputting a part of the kinetic energy to the motor / generator 2, the motor / generator 2
Can function as a generator to generate regenerative braking force (regenerative braking torque).

Next, an example of control of the capacitor 10 and start control of the engine 1 will be described with reference to the flowchart of FIG. First, it is determined whether or not the ignition switch is turned off (corresponding to the lock position of the ignition key) (step 100). If an affirmative determination is made in step 100, the request for starting the engine 1 is not generated, so it is determined whether or not the elapsed time Time from when the ignition switch is turned off is equal to or longer than a predetermined time TDC. (Step 10
1). The predetermined time TDC is stored in the hybrid electronic control device 18 in advance.

If the determination in step 101 is affirmative,
Since it is under the condition that the possibility of starting the engine 1 is low, it is determined whether the voltage Vc of the capacitor 10 is equal to or higher than the predetermined voltage Vcl (step 102). The predetermined voltage Vcl is a value determined based on, for example, the performance of the converter 14 and the like, and corresponds to the lowest voltage at which the capacitor 10 can discharge. Step 1
If an affirmative determination is made in step 02, control is performed to charge the auxiliary battery 15 with the electric energy stored in the capacitor 10 by controlling the switching element of the converter 14 (step 103), and the routine returns.

If a negative determination is made in step 102,
Since the electric energy of the capacitor 10 cannot be charged to the auxiliary battery 15 by the function of the converter 14, the process returns without discharging (discharging) the electric energy of the capacitor 10 (step 104). Note that the control routine is repeated from step 102 to step 103,
If a negative determination is made in step 2, the process proceeds to step 104, and the discharging of the capacitor 10 ends. On the other hand, step 10
If a negative determination is made in step 1, since the ignition switch may be switched to a state other than off in the near future, the process returns without discharging the electric energy of the capacitor 10.

If a negative determination is made in step 100, it is determined whether a request to start the engine 1 has been issued (step 105). For example, if the ignition switch is switched to the start position by operating the ignition key, an affirmative determination is made in step 105, and the voltage Vc of the capacitor 10 becomes the predetermined voltage VCON.
It is determined whether or not this is the case (step 106). The predetermined voltage VCON is, for example, a value estimated to be able to output torque required for starting the engine 1 from the motor generator 2, and the predetermined voltage VCON is stored in the hybrid electronic control device 18.

If an affirmative determination is made in step 106, control for starting the engine 1 is performed by the motor generator 2 (step 107), and the routine returns. On the other hand, if a negative determination is made in step 106,
Since it is difficult to start the engine 1 by the motor / generator 2, the engine 1 is started by the starter motor 8 (step 108) and the process is returned. If the signal of the ignition switch is on or accessory in step 105, a negative determination is made in step 105, and the routine returns without starting the engine 1.

Here, the correspondence between the functional means shown in FIG. 1 and the configuration of the present invention will be described. That is, steps 100 and 103 correspond to the power control means of the present invention, step 101 corresponds to the power supply prohibiting means of the present invention, and steps 106 and 108 correspond to the engine starting means of the present invention.

As described above, according to the control example of FIG. 1, when the ignition switch is turned off, the electric energy stored in the capacitor 10 is stored in the auxiliary battery 1
6 is charged. Therefore, even when a long time has elapsed without a request for starting the engine 1 being generated, the electric energy stored in the capacitor 10 is used as electric power for driving the accessory 16 or the starter motor 8,
Waste of electric energy can be prevented. Furthermore, since waste of electric energy can be prevented,
The frequency of transmitting part of the power of the engine 1 to the motor / generator 2 and causing it to function as a generator is reduced, and fuel efficiency can be improved.

Further, in this control example, a condition during which the request for starting the engine 1 disappears due to the turning off of the ignition switch for less than a predetermined time TDC, that is, a condition in which the request for starting the engine 1 may be generated again. In, the electric energy of the capacitor 10 is maintained as it is without supplying power from the capacitor 10 to the auxiliary battery 15. Therefore, even if the start request of the engine 1 disappears and the start request of the engine 1 is issued again during the predetermined time TDC, the start of the engine 1 can be smoothly performed by the torque of the motor generator 2. ,
The startability of the engine 1 is improved.

Further, according to this control example, when the voltage Vc of the capacitor 10 is lower than the predetermined voltage Vcon,
If it is difficult to start the engine by the generator 2, the engine 1 is started by the starter motor 8. Accordingly, even when the capacitor 10 is discharged after a state in which the start request of the engine 1 is not generated for a long time, the start function of the engine 1 can be ensured. In this embodiment, a different motor generator from the first starting device can be used as the second starting device. In this embodiment, the case where the electronic throttle valve is provided in the engine 1 has been described. However, the throttle valve is of a type in which the operation amount of the accelerator pedal is mechanically reflected on the opening of the throttle valve. It is also applicable to existing vehicles.

[0042]

According to the first aspect of the present invention, the electric energy stored in the power supply for the starting device is charged to the power supply for the functional device under the condition that the request for starting the engine is not generated. Therefore, even if a long period of time has elapsed without a request for starting the engine, the electric energy stored in the power supply for the starting device is used as the electric power of the functional device, and waste of the electric energy can be prevented. .

According to the second aspect of the invention, the same effects as those of the first aspect can be obtained, and in addition, the engine start request is generated for less than a predetermined time after the engine start request has disappeared. Under possible conditions, powering the functional device power supply from the starting device power supply is prohibited. Therefore, even when the request to start the engine is issued again after the request to start the engine has disappeared, the first starting device can smoothly start the engine, and the startability of the engine is improved.

According to the third aspect of the invention, in addition to the same effects as those of the first or second aspect, the voltage of the power supply for the starting device is less than a predetermined value, and the engine is started by the first starting device. Is difficult, the engine is started by the second starting device. Therefore, the engine start function can be ensured even when the power supply for the starter is discharged after the engine start request is not generated for a long time.

[Brief description of the drawings]

FIG. 1 is a flowchart showing one control example of the present invention.

FIG. 2 is a skeleton diagram showing a schematic configuration of a hybrid vehicle to which the present invention is applied.

FIG. 3 is a circuit diagram showing a main part of the hybrid vehicle shown in FIG. 2;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Engine, 2 ... Motor generator, 3 ... Wheel, 8 ... Starter motor, 10 ... Capacitor, 1
4: DCDC converter, 15: auxiliary battery, 16: auxiliary machine.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // B60K 6/00 B60K 9/00 Z 8/00 (72) Inventor Makoto Nakamura Toyota-cho, Toyota-shi, Aichi Prefecture 1st address Toyota Motor Corporation F term (reference) 3G093 AA04 AA05 AA07 AA16 AB00 AB01 BA19 CA01 CB07 DA06 DB05 DB11 DB19 DB23 EB00 EC02 FA11 FB05 5H115 PA12 PC06 PG04 PI13 PI22 PO02 PO17 PU21 PV09 PV23 QE01 SE04 SE06 TE01

Claims (3)

[Claims] 1. An engine for transmitting power to wheels, a first starting device having a function of transmitting power to the wheels and a function of starting the engine, and a starting device for supplying power to the first starting device. A power supply for the device, a power supply for the functional device that is provided separately from the power supply for the starting device, and supplies power to the functional device of the vehicle, and a power supply between the power supply for the starting device and the power supply for the functional device. A power supply device for a hybrid vehicle having a power supply circuit capable of supplying and receiving the power, comprising: a power supply control unit configured to supply the power of the power supply for the starting device to the power supply for the functional device when the request for starting the engine does not occur. A power supply device for a hybrid vehicle. 2. A power supply prohibiting means for prohibiting power supply from the power supply for the starting device to the power supply for the functional device for less than a predetermined time after the engine start request is extinguished. The power supply device for a hybrid vehicle according to claim 1. 3. The functional device includes a second starting device that is provided separately from the first starting device and has a function of starting the engine, and includes a power source for the starting device. When the voltage is equal to or higher than a predetermined value, the engine is started by the first starting device, and when the voltage of the power supply for the starting device is lower than a predetermined value, the engine is started by the second starting device. The power supply device for a hybrid vehicle according to claim 1 or 2, further comprising a starting means.