Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Electric vehicle
Reexamination Certificate
2002-06-21
2004-01-27
Cuchlinski, Jr., William A. (Department: 3661)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Electric vehicle
C180S065310, C320S101000
Reexamination Certificate
active
06684135
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a control device for a fuel cell vehicle using a fuel cell and an electric double layer capacitor, which are connected parallel to each other, as a power supply for a driving electric motor, and more particularly to a process of coping with the occurrence of an abnormal condition in the fuel cell.
2. Description of the Related Art
As a control device, mounted on a fuel cell vehicle, for controlling an output of a driving electric motor for the fuel cell vehicle, for example, a control device constituted as shown in
FIG. 4
is known.
The control device shown in
FIG. 4
has a motor driving unit
101
for supplying a driving electric energy to a driving electric motor
100
and a fuel cell
102
functioning as a power supply for an electric accessory such as an air-conditioner (not shown). An electric double layer capacitor
103
is connected parallel to the fuel cell
102
. At the start time of the generation of an electric energy from the fuel cell
102
, an electric energy is discharged from the electric double layer capacitor
103
to operate a reactive gas supply unit
104
which has an air compressor or the like and supplies reactive gases (hydrogen and air) to the fuel cell
102
, so that the supply of the reactive gases to the fuel cell
102
is started.
An electric vehicle control unit
105
determines a target output (PD_REQ) of the electric motor
100
depending on a rotational speed (Nm) of the electric motor and the amount of depression (Ap) of an accelerator pedal.
A torque command determining unit
106
, provided for the electric vehicle control unit
105
, determines a torque command (TRQ_CMD) so that the electric motor
100
generates the target output (PD_REQ). A reactive-gas-supplied-amount determining unit
107
, provided for the electric vehicle control unit
105
, determines the supplied amount of reactive gases needed to achieve the target output (PD_REQ) and generates a signal indicative of a rotational speed (CMP_CMD) of an air compressor motor necessary to achieve the corresponding supplied amount of reactive gases. Consequently, the amount of generated electric energy depending on the target output (PD_REQ) can be obtained from the fuel cell
102
, so that driving torque depending on the target output (PD_REQ) is generated from the electric motor
101
.
However, in some cases, while the fuel cell vehicle is running, water which is produced by an electrochemical reaction of reactive gases remains in the fuel cell
102
to cause the occurrence of an abnormal condition in which the amount of electric energy generated by the fuel cell
102
decreases. While the target output (PD_REQ) is set at a high level as in the case of, for example, rapidly acceleration of the fuel cell vehicle, when the fuel cell
102
is in the abnormal condition and the amount of electric energy generated by the fuel cell
102
is lower than a level at which the electric energy necessary to operate the reactive gas supply unit
104
can be supplied, the electric energy discharged from the capacitor
103
is consumed by the motor driving unit
101
and the reactive gas supply unit
104
, so that the electric energy charged into the capacitor
103
decreases abruptly.
As mentioned above, when the electric energy charged into the capacitor
103
decreases, there is the following disadvantage: It is difficult to keep the supply of the electric energy at a level necessary to drive the air compressor motor of the reactive gas supply unit
104
. As a result, the fuel cell vehicle cannot run.
SUMMARY OF THE INVENTION
The present invention is made in order to solve the above disadvantage. It is an object of the present invention to provide a control device for a fuel cell vehicle, which suppresses such a fact that the fuel cell vehicle cannot run when an abnormal condition of a fuel cell is caused. There is provided a control device for a fuel cell vehicle, comprising: a fuel cell which is used as a power supply for a driving electric motor; an electric double layer capacitor, connected parallel to the fuel cell, for discharging for compensation for an insufficient electric energy when the amount of electric energy generated by the fuel cell is insufficient; reactive gas supply means, driven by an electric energy supplied from the fuel cell or the electric double layer capacitor, for supplying reactive gases to the fuel cell; and motor driving regenerative means, operated using the fuel cell and the electric double layer capacitor as a power supply, for regulating a driving electric energy supplied to the electric motor depending on a predetermined target torque to control driving torque generated in the electric motor and for regulating a regenerative electric energy recovered from the electric motor to the electric double layer capacitor to control regenerative torque generated in the electric motor.
The control device further comprises upper-limit-amount-of-generated-electric-energy recognizing means for recognizing the operating condition of the fuel cell to recognize the upper limit amount of electric energy generated by the fuel cell depending on the operating condition; current supply limiting means for limiting a current supplied from the fuel cell to the electric double layer capacitor and the motor driving regenerative means; capacitor-charging-amount-of-electric-energy recognizing means for recognizing the amount of electric energy charged into the electric double layer capacitor; and fuel cell abnormality countermeasure means for permitting the current supply limiting means to limit the current supplied from the fuel cell to the electric double layer capacitor and the motor driving regenerative means and permitting the reactive gas supply means to be driven by the regenerative electric energy of the electric motor when the upper limit amount of generated electric energy is equal to a predetermined amount of generated electric energy or lower and the amount of electric energy charged into the electric double layer capacitor is equal to a predetermined amount of charged electric energy or lower while the fuel cell vehicle is running.
According to the present invention, the fuel cell generates a current due to an electrochemical reaction of reactive gases. In some cases, water produced in association with the electrochemical reaction is not completely discharged from the fuel cell but the water remains in the fuel cell. The above-mentioned water remaining in the fuel cell interferes with the supply of the reactive gases to the fuel cell, resulting in a decrease in upper limit amount of electric energy generated by the fuel cell. The electric energy is discharged from the electric double layer capacitor for compensation for the insufficient amount of electric energy generated by the fuel cell, resulting in a decrease in amount of electric energy charged into the electric double layer capacitor. As a result, the fuel cell vehicle may not run.
While the fuel cell vehicle is running, when the upper limit amount of electric energy generated by the fuel cell is equal to the predetermined amount of generated electric energy or lower and the amount of electric energy generated by the fuel cell is equal to the predetermined amount of charged electric energy or lower, the fuel cell abnormality countermeasure means permits the current supply limiting means to limit the current supplied from the fuel cell to the electric double layer capacitor and the motor driving regenerative means and permits the reactive gas supply means to be driven by the regenerative electric energy of the electric motor.
As mentioned above, when the electric energy supplied from the fuel cell to the electric double layer capacitor and the motor driving regenerative means is limited, the amount of electric energy generated by the fuel cell decreases and the amount of reactive gases increases, the reactive gases being not consumed by the fuel cell but passing through the fuel cell as they are. Consequently, the discharge of water rem
Uenodai Asao
Yoshikawa Shinji
Cuchlinski Jr. William A.
Gibson Eric
Honda Giken Kogyo Kabushiki Kaisha
Lahive & Cockfield LLP
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