Chemistry: electrical current producing apparatus – product – and – With pressure equalizing means for liquid immersion operation
Reexamination Certificate
1999-09-10
2001-11-06
Chaney, Carol (Department: 1745)
Chemistry: electrical current producing apparatus, product, and
With pressure equalizing means for liquid immersion operation
C429S010000, C429S010000, C429S010000, C429S006000
Reexamination Certificate
active
06312843
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a fuel cell apparatus, more particular, it relates to the fuel cell apparatus in which a discharge gas having a pressure energy even after an oxygen has been consumed at the fuel cell is expanded at an expanding machine (expander) to collect the pressure energy in the discharge gas as a mechanical energy for assisting driving of a compressor.
2. Related Art
In this kind of fuel cell apparatus, the fuel cell is provided with an air supply tube extending from a compressed air source to the fuel cell, and a discharge gas tube extending from the fuel cell to an atmosphere; the compressor is disposed on the air supply tube, and the expander is disposed on the gas discharge tube respectively. The compressor is driven by an electric motor.
For example, a fuel cell apparatus disclosed in Japanese Unexamined (koukai) Patent Application No. 7-14599 which corresponds to U.S. Pat. Nos. 5,434,016 and 5,645,950, as shown in
FIG. 3
, includes a fuel cell
50
provided with an air supply tube
51
and a gas discharge tube
52
, a compressor
53
disposed on the air supply tube
51
, an expander
54
disposed on the gas discharge tube
52
, and an electric motor
56
for driving the compressor
53
. The air supplied from the air supply tube
51
is compressed to a predetermined pressure value by the compressor
53
and then is supplied to the fuel cell
50
, to consume oxygen contained therein at the fuel cell
50
. The discharge gas of which oxygen is consumed at the fuel cell
50
is then discharged through the gas discharge tube
52
, expanded by the expander
54
down near to an atmospheric pressure. The expander
54
is disposed coaxially with the compressor
53
and is connected thereto by a common shaft
57
to be driven by the electric motor
56
. In
FIG. 3
, reference numerals
58
and
59
each show a water separator,
61
shows a pump,
62
shows a nozzle, and
63
shows a tank, respectively.
This fuel cell apparatus intends to utilize the pressure energy remaining in the discharge gas discharged from the fuel cell
50
for assisting driving or power of the compressor
53
. That is, the pressure energy of the discharge gas is converted to mechanical energy (driving force) by the expander
54
, and the driving force is transmitted via the common shaft
57
to the compressor
53
to assist driving of the compressor
53
by the electric motor
56
.
However, the assisting drive force for the compressor
53
by the expander
54
can be obtained only after a discharge pressure in the gas discharge tube
52
increases up to a predetermined value (rating absorb pressure of the expander
54
), which is realized with a lapse of some time after an operation start of the fuel cell. In other words, before the discharge pressure in the gas discharge tube
52
reaches the predetermined value such as just after start of the fuel cell, expander
54
can not be operated by the discharge gas, so it is operated by the electric motor
56
to expand the discharge gas compulsorily down to below the atmospheric pressure. This means however not only the expander
54
can not collect mechanical energy but the expander
54
consumes electric energy of the electric motor
56
, in other words, a negative torque is transmitted from the expander
54
to the electric motor
56
.
In view of the above, in this conventional fuel cell apparatus, a swing plate valve or an air register
64
is provided between the fuel cell
50
and the expander
54
on the gas discharge tube (upstream of the expander
54
), to introduce the atmosphere into the gas discharge tube
52
, when the pressure in the gas discharge tube
52
is negative, for increasing the pressure therein.
However, even after the swing plate valve
64
is opened, the rotation of the expander
54
by the electric motor
56
continues until the pressure in the gas discharge tube
52
reaches the predetermined value, and the electric energy of the electric motor
56
is consumed for driving the expander
54
. In addition, due to the atmosphere introduced through the swing plate valve
64
by the expander
54
, amount of the air in the gas discharge tube
52
and the expander
54
increases, so that necessary time for increasing the pressure of the discharge gas in the discharge gas
52
is meaninglessly extended.
SUMMARY OF THE INVENTION
The present invention firstly intends to provide a fuel cell apparatus, in which the driving force of the electric motor is not used for driving the expander before the pressure in the gas discharge tube reaches the predetermined value.
The present invention secondarily intends to provide a fuel cell apparatus in which the pressure energy remaining in the discharge gas is converted to mechanical energy by the expander for assisting the driving of the compressor, after the pressure in the gas discharge tube reaches the predetermined value.
The present invention thirdly intends to provide a fuel cell apparatus in which the pressure increasing time in the gas discharge tube in starting of the fuel cell, that is, the time necessary until the pressure in the gas discharge tube reaches the predetermined value, can be shortened.
1) In order to achieve the first object, in the first embodiment of this invention, in a fuel cell apparatus comprising a fuel cell provided with an air supply tube cell and a gas discharge tube, a compressor disposed on the air supply tube, an electric motor for driving the compressor, an expander disposed on the gas discharge tube to be coaxial with said electric motor for expanding a discharge gas discharged from said fuel cell down to an atmospheric pressure, a clutch is disposed between the electric motor and the expander for interrupting the expander from the electric motor, and a control means for controlling the clutch is provided. This control means detects a pressure in the gas discharge tube between said fuel cell and said expander to interrupt said clutch as long as a detected pressure is lower than a predetermined value.
In the second embodiment of this invention, in the above fuel cell apparatus, a one-way clutch is disposed between said electric motor and said expander and idly rotates as long as the number of rotations of said expander is smaller than the number of rotations of said electric motor.
According to this invention, since the expander is connected to the electric motor via the clutch or one-way clutch, the electric motor and the expander are separated by interruption of the clutch or by the one-way clutch, until the pressure in the gas discharge tube reaches the predetermined value.
2) In order to achieve the second object, in the first embodiment, in a fuel cell apparatus comprising a fuel cell provided with an air supply tube cell and a gas discharge tube, a compressor disposed on the air supply tube, an electric motor for driving the compressor, an expander disposed on the gas discharge tube to be coaxial with said electric motor for expanding a discharge gas discharged from said fuel cell down to an atmospheric pressure, a clutch is disposed between said electric motor and said expander for connecting said expander with said electric motor, and a control means for controlling said clutch is provided. This control means detects a pressure in the gas discharge tube between said fuel cell and said expander to connect said clutch when the detected pressure becomes larger than the predetermined value.
In the second embodiment, in the above fuel cell apparatus, a one-way clutch is disposed between said electric motor and said expander for transmitting rotation of said expander to said electric motor and rotating together with said expander when the number of rotations of said expander becomes equal to the number of rotations of the electric motor.
According to this invention, by lapse of short time after starting of the fuel cell, the expander is connected with the electric motor and the compressor by the clutch or by the one-way clutch. As a result, the pressure energy of the discharge gas is collected as
Ban Takashi
Katoh Hirohisa
Kimbara Masahiko
Kubo Hidehito
Chaney Carol
Kabushiki Kaisha Toyoda Jidoshokki Seisakusho
Morgan & Finnegan , LLP
Yuan Dah-Wei D.
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