Communications: electrical – Land vehicle alarms or indicators – Internal alarm or indicator responsive to a condition of the...
Reexamination Certificate
2001-11-30
2004-02-10
Wu, Daniel J. (Department: 2632)
Communications: electrical
Land vehicle alarms or indicators
Internal alarm or indicator responsive to a condition of the...
C340S439000, C340S459000, C340S635000, C340S870030
Reexamination Certificate
active
06690269
ABSTRACT:
This application is based on Application No. 2001-172703, filed in Japan on Jun. 7, 2001, the contents of which are hereby incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a control unit for an internal combustion engine, and in particular to the detection of abnormality in an internal combustion engine and the generation of warnings based on the abnormality detected.
2. Description of the Related Art
FIG. 4
is a schematic constructional view illustrating those portions of such a kind of known control unit for an internal combustion engine which relate particularly to the detection of abnormality and the generation of warnings based on the abnormality detected. In this figure, the control unit for an internal combustion engine (hereinafter abbreviated as ECU), generally designated at a reference numeral
1
, is connected with abnormality detection devices
2
(though only one is illustrated) such as a variety of kinds of sensors, switches and so on, for example, for controlling the internal combustion engine (hereinafter simply referred to as an engine), and with warning devices such as a lamp
3
and a buzzer
4
for informing a user (driver, passengers, etc.) of the occurrence of abnormality based on the detection thereof.
The ECU
1
includes a control CPU
5
, input interface (“I/F”) circuits
6
provided one for each of the abnormality detection devices
2
, output I/F circuits
7
a
,
7
b
provided one for each of the warning devices comprising the lamp
3
, the buzzer
4
, etc, an input side connector
1
a
having a plurality of input terminals
2
p
provided one for each of the abnormality detection devices
2
, and an output side connector
1
b
having a plurality of output terminals
3
p
,
4
p
provided one for each of the warning devices
3
,
4
.
FIG. 5
particularly illustrates the circuit structure of one input I/F circuit
6
and one set of output I/F circuits
7
a
,
7
b
of the known control unit for an internal combustion engine of FIG.
4
. The input I/F circuit
6
includes a transistor Tr
1
, pull-up resistors R
1
, R
2
, a diode D
1
for protection from an external negative surge voltage, and a combination of a capacitor C
1
and a resistor R
3
together constituting an RC filter for preventing chattering by smoothing an input signal to the transistor Tr
1
.
The output I/F circuits
7
a
and
7
b
include transistors Tr
1
a
, Tr
1
b
, pull-up resistors R
11
a
, R
11
b
, resistors R
12
a
, R
12
b
connected with the base sides of the transistors Tr
11
a
, Tr
11
b
, respectively, and resistors R
13
a
, R
13
b
connected with the collector sides of the transistors Tr
11
a
, Tr
11
b
, respectively.
Now, the operation of the circuit of
FIG. 5
will be described briefly. When abnormality is detected by an abnormality detection device
2
, this abnormality detection device
2
shown as a switch in
FIG. 5
is closed, whereby the transistor Tr
1
of the input I/F circuit
6
is placed into an off state, permitting a high (H) level signal representative of the detection of abnormality to be input to the CPU
5
. As a result, the CPU
5
outputs H level signals to the output I/F circuits
7
a
,
7
b
, respectively. That is, current is supplied from a power supply Vcc to the transistors Tr
11
a
, Tr
11
b
, which are thereby turned on, driving the respective warning devices such as the lamp
3
and the buzzer
4
to generate warnings of light and sound.
In the past, the control unit for an internal combustion engine, i.e., ECU
1
, performs various control operations (e.g., ignition timing control, fuel injection control, etc.) for the internal combustion engine, and at the same time detects various abnormality states of the engine thereby to generate warnings to the user (in general, the driver).
To this end, there are provided the abnormality detection devices
2
such as, for example, various sensors, switches and the like, and the warning devices such as the warning lamps
3
, the warning buzzers
4
and the like. Connected with the ECU
1
are abnormality detection devices
2
and the warning devices
3
,
4
for detecting and warning of the above-mentioned abnormal states, so that the detection of abnormal states and the generation of warnings are controlled by means of the CPU
5
incorporated in the ECU
1
.
Here, it is to be noted that the input I/F circuits
6
and the input terminals
2
p
equal in number to the abnormality detection devices
2
are required though only one for each of them is illustrated in
FIGS. 4 and 5
for the sake of concise explanation. Also, the output I/F circuits
7
a
,
7
b
and the output terminals
3
p
,
4
p
equal in number to the corresponding warning devices
3
,
4
, are required though only two of them are illustrated in
FIGS. 4 and 5
for the sake of concise explanation.
In this manner, one or more warning devices is generally provided for one abnormality detection device in this kind of known control unit for an internal combustion engine, and hence two or more input terminals and output terminals of the control unit for an internal combustion engine are necessary.
At present, the number of kinds of warning control operations to be performed in the control unit for an internal combustion engine, i.e., the ECU, tends to increase, and hence the number of input and output terminals accordingly increases, too. As the number of the input and output terminals increases, the number of terminals of the connectors to be used accordingly increases, too. In addition, the size of the connectors also increases, thus resulting in an increase in size of the ECU.
In these circumstances, connector manufactures are now in the process of developing connectors with many terminals in order to cope with the increasing number of the input and output terminals. However, there is a tendency that the connectors newly developed in this manner become greater in size than the existing ones.
On the other hand, the configuration of the engine surroundings are also becoming more and more complicated in accordance with the increasing power, environmental response, etc., of an engine. As a consequence, miniaturization and weight reduction of the ECU come to be important problems.
SUMMARY OF THE INVENTION
The present invention is intended to obviate the problems as referred to above and has for its object to provide a control unit for an internal combustion engine in which the number of input and output terminals can be reduced for miniaturization and weight reduction thereof while maintaining the function of detecting an abnormality of an existing internal combustion engine and generating a warning based thereon.
Bearing the above object in mind, the present invention resides in a control unit for an internal combustion engine comprising: an input and output I/F circuit connected through a common signal line with an abnormality detection device, which generates an abnormality detection signal when an abnormality of the internal combustion engine is detected, and with at least one warning device, which generates a warning based on the abnormality detected, the input and output I/F circuit being adapted to receive an abnormality detection signal from the abnormality detection device and output a drive and hold signal to the warning device; and an arithmetic processing section for controlling the abnormality detection device and the warning device through the input and output I/F circuit in such a manner that a drive and hold signal is output to the warning device when the abnormality detection signal is input to the arithmetic processing section.
In a preferred form of the present invention, the control unit is provided with one input and output terminal for the one common signal line.
In another preferred form of the present invention, the arithmetic processing section disregards an abnormality detection signal from the abnormality detection device during the period in which a drive and hold signal is output to the warning device.
In a further preferred form of the present invention,
Mitsubishi Denki & Kabushiki Kaisha
Nguyen Hung
Wu Daniel J.
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