Measuring and testing – Simulating operating condition – Marine
Reexamination Certificate
1997-07-29
2001-01-09
Dombroske, George (Department: 2855)
Measuring and testing
Simulating operating condition
Marine
C701S031000
Reexamination Certificate
active
06170323
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a vehicle meter self-diagnosis apparatus for diagnosing a condition such as a broken line or a short circuit of vehicle electric analog meters each using a cross coil movement and a method of starting a self-diagnosis mode of the self-diagnosis apparatus.
2. Description of the Related Art
If a meter seems to fail, a self-diagnosis apparatus is used to carry out a diagnosis for determining a failure place (the meter or a sensor) at a dealer or a service garage.
An apparatus shown in
FIG. 11
is known as such a conventional vehicle meter self-diagnosis apparatus, for example, as disclosed in Japanese Utility Model Laid-Open No. Sho 62-195776.
FIG. 11
is a circuit diagram to show a conventional vehicle meter self-diagnosis apparatus.
FIG. 12
is a block diagram of a conventional self-diagnosis start control circuit.
FIG. 13
is a block diagram of a conventional odo/trip signal processing circuit.
In
FIG. 11
, numeral
100
is an incorporated pseudo signal generation circuit, numeral
101
is a speed signal, numerals
102
and
104
are input circuits, numeral
103
is an engine rotation signal, numeral
105
is a fuel remaining amount signal, numeral
106
is a water temperature signal, numeral
107
is an A/D (analog-digital) converter, numeral
108
is a CPU (central processing unit) for performing signal processing, operations, etc., numeral
109
is an LCD (liquid crystal display) for producing odd/trip display, and numeral
110
is a driver for driving the LCD
109
.
Numeral
111
is a speed meter made up of components such as a cross coil movement having a pair of coils placed so as to cross each other at an angle of 90 degrees and a moving magnet for indication placed rotatably under a magnetic field produced by the coils, numeral
112
is a driver for driving the speed meter
111
, numeral
113
is a tachometer, numeral
114
is a driver for driving the tachometer
113
, numeral
115
is a fuel gauge, numeral
116
is a driver for driving the fuel gauge
115
, numeral
117
is a water temperature gauge, and numeral
118
is a driver for driving the water temperature gauge
117
.
Numeral
120
is a driver control circuit for controlling the drivers
112
,
114
,
116
, and
118
and numeral
122
is a ROM (read-only memory) of a nonvolatile memory into which indication adjustment information such as pointer swing angles of the speed meter
111
, the tachometer
113
, the fuel gauge
115
, and the water temperature gauge
117
are written. Numeral
132
is an odd/trip meter reset switch.
In
FIG. 12
, numeral
140
is a self-diagnosis start control circuit being provided in the CPU
108
for the odo/trip LCD
109
, the speed meter
111
, the tachometer
113
, the fuel gauge
115
, and the water temperature gauge
117
.
The self-diagnosis start control circuit
140
comprises a power supply sequence connected to a battery
150
via a power supply circuit
152
, an odd/trip signal processing circuit
142
for performing predetermined signal processing to produce odd/trip display on the LCD
109
, and an LCD driver interface
143
of an interface to the driver
110
. Numeral
154
is an ignition switch.
As shown in
FIG. 13
, the odd/trip signal processing circuit
142
comprises a sensing section
142
a
for sensing that the ignition switch
154
is on or off and a data output section
142
b
for outputting segment data to the LCD driver interface
143
in response to output of the sensing section
142
a
. The output of the sensing section
142
a
is connected to the pseudo signal generation circuit
100
.
Next, the operation will be discussed.
FIG. 14
is a flowchart to show the operation of the conventional vehicle meter self-diagnosis apparatus. While the reset switch
132
is turned on with the battery
150
on, the ignition switch
154
is turned on at step ST
1
. Then, the sensing section
142
a
senses that the ignition switch
154
is turned on, and control goes to step ST
2
.
If the reset switch
132
is not turned on and the ignition switch
154
is not turned on either, the LCD
109
does not go on. If the reset switch
132
is not turned on and the ignition switch
154
is turned on, the vehicles enter the normal operation mode.
At step ST
2
, the data output section
142
b
outputs predetermined segment data to the LCD driver interface
143
and the LCD driver interface
143
and the driver
110
check the LCD
109
for segments.
In the cross coil movement, the pseudo signal generation circuit
100
is also started by the operation and shifts to the self-diagnosis mode and the speed meter
111
the tachometer
113
, the fuel gauge
115
, and the water temperature gauge
117
are operated in response to indication adjustment information such as swing angles and sweep time preset as pseudo signals in the pseudo signal generation circuit
100
. whether or not a failure occurs is determined according to the operation information.
An apparatus shown in
FIG. 15
is known as another conventional vehicle meter self-diagnosis apparatus. In the figure, numeral
160
is a pseudo signal generator connected from the outside. Other components and the operation are similar to those in the conventional example described above and will not be discussed again.
Since the conventional vehicle meter self-diagnosis apparatus is thus configured, the input circuits
102
and
104
, the A/D converter
107
, the CPU
108
, and the like with a large number of circuit elements and a high failure probability must be used to start the self-diagnosis mode. If the circuit itself fails, which of the circuit or the cross coil movement fails cannot be determined and the reliability of the self diagnosis is degraded.
Since the self-diagnosis mode is started only by turning on both the reset switch
132
and the ignition switch
154
at the same time, there is a possibility that general users will starts the self-diagnosis mode by mistake. Once the self-diagnosis mode is started by mistake, the meters are determined to fail.
Further, to use the pseudo signal generator
160
to carry out a self-diagnosis, the vehicle meters must be removed to input predetermined signals; it is difficult to carry out an easy and prompt diagnosis.
SUMMARY OF THE INVENTION
The invention has been made in view of the above circumstance, and therefore an object of the invention is to provide a vehicle meter self-diagnosis apparatus that can carry out an easy and prompt diagnosis with high reliability.
It is another object of the invention to provide a method of starting a vehicle meter self-diagnosis mode that can prevent general users from starting a self-diagnosis mode by mistake.
According to a first aspect of the invention, there is provided a vehicle meter self-diagnosis apparatus, comprising cross coil movements, drivers for driving the cross coil movements, a driver control circuit for controlling the drivers, a nonvolatile memory into which indication adjustment information of the cross coil movements is written, a central processing unit for inputting the indication adjustment information in the nonvolatile memory to the drive control circuit based on an input signal from a sensor and controlling the driver control circuit, and a self-diagnosis control circuit being started by start means, for driving the drivers and diagnosing the cross coil movements.
According to a second aspect of the invention, there is provided a method of starting a vehicle meter self-diagnosis mode, comprising the steps of: turning on power, turning on an ignition switch while turning on start means of a self-diagnosis control circuit for a predetermined time, and turning on the start means a predetermined number of times within a predetermined time after turning on the ignition switch, thereby starting a self-diagnosis mode for diagnosing vehicle meters.
The above and other objects and features of the present invention will be more apparent from the following description taken in conjunction with the accompanying drawings.
REFERENCES:
patent: 5174238
Enomoto Akihiro
Kobayashi Masakazu
Tanaka Yoichiro
Dombroske George
Kansei Corporation
Sughrue Mion Zinn Macpeak & Seas, PLLC
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