Electricity: motive power systems – Constant motor current – load and/or torque control
Reexamination Certificate
2000-10-02
2001-12-25
Nappi, Robert E. (Department: 2837)
Electricity: motive power systems
Constant motor current, load and/or torque control
C318S139000, C180S065230, C180S165000
Reexamination Certificate
active
06333612
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a motor control apparatus for a hybrid vehicle which carries a combustion engine and a motor.
This application is based on Japanese Patent Application No. 11-283579, the contents of which are incorporated herein by reference.
2. Description of the Related Art
To improve the driveability of a vehicle, a control apparatus, which can respond without delay to instructions from a driver to accelerate or decelerate the vehicle, is required. A hybrid vehicle which has a combustion engine and a motor must control without delay the amount of electric energy which is supplied to the motor, or which is drawn from the motor. The hybrid vehicle supplies the electric energy to the motor, and the motor assists the engine to accelerate the vehicle. Further, the hybrid vehicle uses the motor as a generator, and the generated electric energy is drawn so that the vehicle decelerates.
To achieve the control without delay, the gain supplied from the control apparatus to the motor may be increased, and, alternatively, the rate of change of electric energy per unit time drawn from the motor may be increased, and the rate of change of the motor torque per unit time may be increased.
To achieve the above-mentioned control, a structure for drawing and supplying the electric energy to the motor must be provided, and the structure may unbalance the energy management when the engine is idling, or when the vehicle is cruising at a constant speed. When the engine is idling, or when the vehicle is cruising, the motor acts as a generator to send the generated energy to the battery, and the battery is charged. The amount of electric energy stored in the battery cannot be accurately known only by detecting the electric energy which is supplied to or sent from the motor. The reason for this is that the battery is not only connected to the motor but also connected to various other electrical equipment which consumes electric energy, and that the electric energy supplied to and sent from the motor is not necessarily the same as that supplied to and sent from the battery.
To solve this problem, the electric energy supplied to and sent from the battery may be detected. However, according to the structure for detecting the electric energy and for controlling the detected value to maintain it at a fixed value, when the motor generates electric energy while the vehicle is idling or cruising, the motor generates the electric energy to be consumed by the electrical equipment such as the air conditioner, head lights, and defroster, and the electric energy to be supplied to the battery. Therefore, variations in the electric energy consumed by the electrical equipment appears as a variation in electric energy generated by the motor.
According to this structure, when electrical equipment is turned on or off while the engine is idling, the electric energy generated by the motor varies, the load on the engine also varies, and the engine may therefore stall.
Further, when electrical equipment is turned on or off while the vehicle is cruising, the electric energy generated by the motor varies, the load on the engine also varies, and the vehicle may behaves unstably.
BRIEF SUMMARY OF THE INVENTION
It is therefore a first object of the present invention to provide a motor control apparatus for a hybrid vehicle which can respond to instructions of the driver to accelerate or decelerate the vehicle while balancing the energy management when the engine is idling or when the vehicle is cruising.
It is a second object of the present invention to provide a motor control apparatus for a hybrid vehicle which can prevent the engine from stalling even when electrical equipment is turned on or off while the engine is idling, and which can prevent the unstable behavior of the vehicle even when the electrical equipment is turned on or off while the vehicle is cruising.
It is therefore a third object of the present invention to provide a motor control apparatus for a hybrid vehicle which can respond to an instruction of a driver to accelerate or decelerate the vehicle while balancing the energy management when the engine is idling or when the vehicle is cruising, which can prevent the engine from stalling even when electrical equipment is turned on or off while the engine is idling, and which can prevent the unstable behavior of the vehicle even when the electrical equipment is turned on or off while the vehicle is cruising.
In a first aspect of the present invention, a motor control apparatus for a hybrid vehicle is provided with a combustion engine (
10
) for outputting driving force, an electric motor (
2
) for generating a force for assisting the output from the engine, a power storage unit (the main battery
1
) for supplying electric power to the motor and for storing electric energy regenerated by the motor, and an electrical equipment (
5
) which is operated by the electric power. The motor control apparatus comprises: a first electric power measuring device (
6
) for measuring the electric power supplied from or stored in the power storage unit; a second electric power measuring device (
7
) for measuring the electric power supplied to or drawn from the motor; a drive mode determining device (
11
) for determining the drive mode, based on a predetermined parameter; a measured electric power selector (
16
) for selecting one of the value measured by the first electric power measuring device and the value measured by the second electric power measuring device, depending on the determination by the drive mode determining device; and a motor controller (the feedback processor
15
, and the power drive unit
3
) for controlling the electric power which is to be supplied to or is to be drawn from the motor, depending on the measured value selected by the measured electric power selector.
According the first aspect of the present invention, the measured electric power selector selects one of the value measured by the first electric power measuring device and the value measured by the second electric power measuring device, depending on the drive mode determined by the drive mode determining device. Namely, the measured electric power selector selects one of the electric power supplied from or stored in the battery and the electric power supplied to or drawn from the motor. Therefore, the motor control apparatus is responsive to a driver's instruction to accelerate or decelerate the vehicle in the assistance mode or in the deceleration mode, while balancing the energy management when the vehicle is idling or cruising.
In a second aspect of the present invention, the motor control apparatus comprises: an electric power measuring device (the first electric power measuring device
6
, and the second electric power measuring device
7
) for measuring the electric power transferred between the power storage unit and the motor; a motor controller (the feedback processor
15
, and the power drive unit
3
) for controlling the electric power which is to be supplied to the motor or which is to be drawn from the motor, depending on the value measured by the electric power measuring device; a drive mode determining device (
11
) for determining the drive mode, based on a predetermined parameter;, and a gain switcher (
14
) for switching a gain which defines a rate of change of the torque of the motor, depending on the determination by the drive mode determining device. The motor controller controls the electric power which is to be supplied to or is to be drawn from the motor, depending on the rate of change defined by the gain switched by the gain switcher.
According the second aspect of the present invention, the gain switcher switches a gain which defines a rate of change in torque of the motor, depending on the determination by the drive mode determining device. Therefore, the motor control apparatus is responsive to driver's instructions to accelerate or decelerate the vehicle in the assistance mode or in the deceleration mode, while preventing the engi
Hara Kazuhiro
Ochiai Shinobu
Suzuki Minoru
Yoshikawa Shinji
Arent Fox Kintner & Plotkin & Kahn, PLLC
Duda Rina I.
Honda Giken Kogyo Kabushiki Kaisha
Nappi Robert E.
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