Method and system for indicating automobile abnormal conditions

A system for indicating an abnormal condition of an automobile in which the condition of inspection items relating to the driving of the automobile is detected, and running speed of the automobile is detected. The system decides that the condition of an inspection item has reached a first abnormal level, and upon detection of the stoppage of the automobile after the time point of the decision, a voice cautioning the driver of the abnormal condition of the inspection item is automatically generated. Upon detection of the fact that a second abnormal level higher than the first abnormal level has been reached, a voice warning the driver of the abnormal condition of the inspection item is generated regardless of the driving condition of the automobile.

The present invention relates to a method and a system for orally 
indicating an abnormal condition included in predetermined inspection 
items for driving an automobile. 
In the prior art, an automobile has an OK monitor which lights a lamp 
indicating a point of trouble at the time of occurrence thereof, which OK 
monitor watches the conditions of the head lamps, the brake lamps, the 
tail lamps, the washer liquid, the battery liquid, the radiator liquid and 
the like. 
This OK monitor informs the driver of a point of trouble by the lighting of 
a lamp, and therefore it may be possible that the driver overlooks the 
warning of the particular trouble while driving the automobile. In recent 
years, means for warning the driver of a trouble using a voice such as a 
voice synthesizer have come to find practical applications. If such means 
issues a warning frequently, the driving skill may be adversely affected. 
Especially if a warning of a small trouble is issued while the automobile 
is being driven, the driver may psychologically, be undesirably upset. 
The present invention has been developed in view of this problem, and an 
object of this invention is to provide a method including the following 
steps and an apparatus for performing the method. The method according to 
this invention, comprises steps of monitoring the conditions of items to 
be inspected in driving the automobile, deciding that the condition of an 
inspection item has reached a first abnormal level, detecting that the 
driving of the automobile has been stopped upon or after the time of the 
decision, automatically issuing a voice warning of the abnormal condition 
of the particular inspection item upon the detection of automobile 
stoppage, deciding that the condition of the particular inspection item 
has reached a second abnormal level higher in abnormality than the first 
abnormal level, and automatically issuing a voice warning the driver of 
the abnormal condition of the inspection item regardless of the running 
condition of the automobile at the time of the second decision, to make it 
possible to inform the driver orally of the abnormal condition of the 
inspection item without causing any unnecessary strain of the driver while 
at the same time enabling him to carry out the instructions specified to 
rectify the abnormal condition. 
According to the present invention, the degree of abnormality of the 
inspection items is divided into two levels for decision, so that in the 
case of an abnormal condition low in abnormality level, the driver is 
informed of the abnormal condition by voice only after the automobile has 
stopped, thus the driver is prevented from being exposed to unnecessary 
strain. 
According to another aspect of the present invention, it is possible to 
indicate an abnormal condition of the automobile pertinently by using a 
speed sensor for detecting the running condition of the automobile 
correctly.

The present invention will be described below with reference to the 
embodiments shown in the accompanying drawings. FIG. 1 shows a general 
construction of an embodiment, which uses a car-mounted microcomputer for 
executing a software digital operation in accordance with a predetermined 
program of abnormal condition indication. 
In FIG. 1, reference numeral 1 designates a central processing unit of the 
car-mounted microcomputer. This central processing unit 1 has a crystal 
oscillator 2 to produce a reference clock of several MHz, in synchronism 
with which a software digital operation is executed. The central 
processing unit 1 is also connected with operational means comprising a 
read only memory (ROM) 6, a random access memory (RAM) 7 and an 
input-output circuit 8 for transmitting and receiving various information 
through an address bus 3, a control bus 4 and a data bus 5. These 
component elements are all made of semiconductor integrated circuits. The 
read only memory 6 contains an abnormal condition indication program in 
which the operational sequence for detecting an abnormal condition and 
oral indication thereof is recorded by step, and voice data for generating 
a predetermined voice for making such a voice indication. This operational 
process is executed by the central processing unit 1 sequentially reading 
out the operational steps. The various data in the course of operation are 
temporarily stored in the random access memory 7 on the one hand and read 
out as required on the other hand. 
Further, the input-output of various signals between the central processing 
unit 1 and the car-mounted microcomputer and external devices is regulated 
by the input-output circuit 8. 
Numeral 9 designates a cooling water temperature sensor, including a 
thermistor or the like, namely, means for detecting the temperature of the 
cooling water of the engine. Numeral 10 designates a car speed sensor 
arranged in the vicinity of a rotary magnet within a speed meter, which 
speed sensor 10 comprises an electromagnetic pick-up for generating an 
on-off signal proportional to the car speed and an F/V converter for 
converting the signal produced by the electromagnetic pick-up into an 
analog car speed voltage. Numeral 11 designates a stop switch adapted to 
be turned on when it is desired to stop the voice generation. This switch 
11 is mounted on an instrument panel or handle for easy operation by the 
driver. Numeral 12 designate an A/D converter for converting an analog 
signal into a digital signal, which converts the water temperature signal 
produced by the cooling water temperature sensor 9 and the car speed 
signal produced by the car speed sensor 10 into digital signals 
sequentially. 
Numeral 13 designates a timer circuit comprising a flip-flop supplied with 
a set-reset signal from the output of the input-output circuit 8, an 
oscillator circuit which starts oscillation in response to the activation 
or set of the flip-flop, and a counter for counting the oscillation pulses 
from the oscillator circuit and producing a 1-minute pulse to resume the 
counting operation from the initial state when the count reaches a time 
length corresponding to one minute. When this counter is set, it produces 
a 1-minute pulse for every minute. Numeral 14 designates an indicator 
including first and second flip-flop supplied with set and reset signals 
from the input-output circuit 8, and yellow and red lamps adapted to be 
lit in response to the output of the first and second flip-flops. By 
lighting one of the yellow and red lamps, the letters warning the driver 
of the overheat preprinted on the indication screen are displayed. Numeral 
15 designates a digital voice synthesizer, which together with the speaker 
18, makes up voice generator means. The digital voice synthesizer 15 
synthesizes and produces speech in response to the voice data sequentially 
delivered from the input-output circuit 8, and uses, for instance, a 
digital voice synthesizer of COR type described in The Electronics 
Technology (Denshi Gijutsu), Vol. 21, No. 12. Numeral 16 designates a D 
flip-flop which is supplied with the signal from the stop switch 11 at the 
clock terminal CLK and the reset signal from the input-output circuit 8 at 
the reset terminal R. Numeral 17 designates a relay circuit including a 
normally-closed relay by which the signal transmission between the speaker 
18 and the amplifier in the last stage of the digital voice synthesizer 15 
is subjected to on-off control in response to the output signal from the D 
flip-flop 16. Specifically, when the output signal from the D flip-flop 16 
is at low level, the signal transmission is turned on, while when the 
output signal is at high level, the signal transmission is turned off. The 
component elements 1 to 18 included in this general configuration diagram 
are adapted to be actuated in response to the stabilizing voltage Vcc 
produced from a stabilized power circuit (not shown) operated by the power 
supplied from the car-mounted battery when the key switch (not shown) is 
turned on. 
Now, the operation of the circuits of the above-mentioned general 
construction described above will be described with reference to the 
operational flowchart shown in FIGS. 2 to 5. 
As already explained, FIG. 2 is an operational flowchart showing the 
processes of the operating routine of overheat indication among the 
operations of the microcomputer according to an abnormal condition 
indication program, FIG. 3 is an operational flowchart showing the 
processes of an operating routine of overheat announcement in FIG. 2, FIG. 
4 is an operational flowchart showing the processes of the routine of 
caution, warning and processing of overheat in FIG. 3, and FIG. 5 is an 
operational flowchart showing the processes of an interrupting operation 
routine based on the 1-minute pulse from the timer circuit. 
In an automobile having these devices, when the key switch thereof is 
turned on for starting the driving thereof, stabilized power supply 
circuit not shown supplies a stabilized voltage to the component elements 
1 to 18 to actuate them. By the start of operation, the register, the 
counter, the latch and the like in the microcomputer are set in an initial 
condition required to start the operational processes. This initial 
setting process includes the setting of a set flag and a first flag, 
cancellation of a reset flag, a caution flag and a warning flag, resetting 
of the condition of the data of number of times N.sub.1, N.sub.2 and 
N.sub.3 to make N.sub.1 =N.sub.2 =N.sub.3 =0, and delivery of a reset 
signal to the flip-flop of the timer circuit 13 and the first and second 
flip-flops of the indicator 14. After the initial setting, the operational 
processes of the main routine including the overheat indication routine of 
FIG. 2 are repeated in predetermined cycles. 
In the overheat indication operational routine in the repeated processes of 
the main routine, the operational process is started from the water 
temperature input step 101 of FIG. 2, so that the water temperature signal 
from the cooling water temperature sensor 9 is stored at the step 101 
through the A/D converter 12. Under this condition, the water temperature 
data T applied is comparatively low since it is at the time of the 
starting of the engine operation. Thus, the result of the process at the 
next first water temperature decision step 102 for deciding whether the 
water temperature T is higher than a decision level .alpha. such as 
90.degree. C. or not becomes "No", and the transfer is made to the reset 
flag judging step 109 where, since the reset flag is cancelled by the 
initial setting, the decision becomes "No", thus completing the first 
indication operation of the overheat indication operational routine. The 
operational processes of the main routine including the processes of the 
overheat indication operational routine are repeated in predetermined 
cycles, and the overheat indication is not effected by the indicator 14 or 
the speaker 18. 
Thereafter, the temperature of the cooling water increases gradually as the 
automobile continues to be driven. When the temperature of the cooling 
water reaches 90.degree. C. for some reason or other, the water 
temperature data T of 90.degree. C. or higher is applied to and stored at 
the water temperature input step 101 in FIG. 2. Thus, the decision at the 
next first water temperature decision step 102 becomes "Yes", and the 
route to the set flag decision step 103 is taken. Since the set flag is 
already set by initial setting, the decision at the step 103 becomes 
"Yes", thus advancing to the .alpha. level conversion step 104. At the 
.alpha. level conversion step 104, the decision level .alpha. is converted 
to a predetermined value such as a value corresponding to 85.degree. C. 
for the purpose of providing a hysteresis to the decision of the first 
water temperature decision step 102, and transfer is made to the set 
signal supply step 105. At this set signal supply step 105, a set signal 
is supplied to the flip-flop of the timer circuit 13 for the purpose of 
starting the operation of the particular timer. Then the route is taken to 
the set flag caoncel step 106 for cancelling the set flag, followed by 
transfer to the reset flag set step 107 for setting the reset flag. Then 
the route to the storage step 108 is taken to store the water temperature 
data T at the current time at a predetermined address of the random access 
memory 7 to proving an old water temperature data To, followed by transfer 
to the overheat announcement operational routine 200. At this overheat 
announcement operational routine 200, the operational process is started 
from the second water temperature decision step 201 in FIG. 3 thereby to 
decide whether the water temperature data T is higher than a value 
corresponding to the decision level .beta. such as 115.degree. C. or not. 
Since it is immediately after the water temperature data T reached a value 
corresponding to 90.degree. C., the decision at the step 201 is "No", 
followed by transfer to the .beta. level conversion cancel step 211. At 
this .beta. level conversion cancel step 211, a calculation is made to 
return to the initial level if the decision level .beta. is converted to 
provide a hysteresis to the decision at the second water temperature 
decision step 201. In view of the fact that the decision level .beta. is 
not converted in this case, however, the particular value is kept and 
transfer is made to the next step 212 for resetting number of times. At 
the step 212 where the number of times is reset, the first time data 
N.sub.1 is reset to zero, followed by advance to the red indication 
extinction step 213 for supplying a reset signal to the second flip-flop 
for lighting the read lamp in the indicator 14. Then transfer is made to 
the overheat caution and warning operational routine 300. At this overheat 
caution and warning operational routine 300, the operational processes are 
started from the caution flag decision step 301 in FIG. 4 thereby to 
decide whether the caution flag is set or not. In view of the fact that 
the caution flag is cancelled by an initial setting, the decision becomes 
"No" and transfer is made to the warning flag decision step 308. At this 
warning flag decision step 308, it is decided whether the warning flag is 
set or not. Since the warning flag is cancelled by initial setting, the 
decision at the step 308 becomes "No", followed by transfer to the voice 
reset signal supply step 315. At the voice reset signal supply step 315, a 
reset signal is applied to the D flip-flop 16 in order to reduce the 
output of the D flip-flop 16 to low level, thus completing one operational 
process of the overheat caution and warning operational routine, namely, 
one operational process of the overheat indication operational routine. As 
a result, the set signal supplied from the set signal supply step 105 in 
FIG. 2 causes the timer circuit 13 to start the counting operation of the 
counter. When it proceeds to the set flag decision step 103 of FIG. 2 in 
the overheat indication operational routine, the decision at the step 103 
becomes "No" since the set flag is cancelled at the set flag cancel step 
106 in the previous operational cycle, so that a change is immediately 
made to the operational process for advancing to the overheat announcement 
operational routine 200. 
Subsequently, when the counter of the timer circuit 13 counts the time 
length of one minute and supplies a 1-minute pulse to the interruption 
terminal INT of the central processing unit 1, the microcomputer 
temporarily stops the operational process of the main routine and starts 
the operational process of the interruption routine shown in FIG. 5 from 
the interruption start step 401. Transfer is thus made to the water 
temperature input step 402 to supply the water temperature data T based on 
the water temperature signal from the cooling water temperature sensor 9, 
followed by transfer to the read-out step 403 where the old water 
temperature data To of one minute before is read out from the 
predetermined address of the random access memory 7. Then transfer is made 
to the change calculation step 404 for determining the amount of change in 
water temperature for one minute from the formula R.sub.T =T-To. In this 
case, if the amount of change R.sub.T is lower than the predetermined 
value A, the decision at the next first change decision step 405 becomes 
"No", followed by transfer to the storage step 408 so that the water 
temperature T at that time is stored at a predetermined address of the 
random access memory 7 as an old water temperature data To. Advance is 
made to the return step 409 for restoring the operational process of the 
main routine that has temporarily been stopped. 
Thereafter, the above-mentioned interruption operational process is 
executed at intervals of one minute in parallel with the operational 
process of the main routine. When the increase in the temperature of the 
cooling water causes the change R.sub.T determined at the change 
calculation step 404 to reach the predetermined value A, the next change 
decision step 405 becomes "Yes". Advance is made to the second change 
decision step 406 to decide whether the amount of change R.sub.T is higher 
than a predetermined value B (B&gt;A) or not. Since the amount of change 
R.sub.T is such a value as to reach the predetermined value A, the 
decision is "No", followed by transfer to the first flag decision step 
410, the decision at the step 410 becomes "Yes" since the first flag is 
set by initial setting. Advance is made to the caution flag set step 41 to 
set a caution flag, followed by transfer to the first flag cancel step 412 
thereby to cancel the first flag. Advance is made through the storage step 
408 to the return step 409 thereby to restore the operational process of 
the main routine thus far provisionally suspended in operation. 
As a consequence, at the main routine, when it proceeds to the caution flag 
decision step 301 of FIG. 4 in the overheat indication operational 
routine, the decision at the step 301 becomes "Yes", and thus advance is 
made to the car speed input step 302 for supplying the car speed signal 
from the car speed sensor 10 through the A/D converter 12. At this time, 
if the automobile is being driven or running and the car speed data S 
supplied at the car speed input step 302 is not zero, the decision at the 
next stop decision step 303 becomes "No", thus completing one operational 
process of the overheat indication operational routine. 
When the running of the automobile is stopped such as by a stop traffic 
signal at an intersection or the like, while repeating the above-mentioned 
operational processes, the car speed data S supplied at the car speed 
input step 302 becomes zero and therefore the decision at the next stop 
decision step 303 becomes "Yes". Transfer is then made to the addition 
step 304 where 1 is added to the second number of times data N.sub.2, that 
is to make N.sub.2 =N.sub.2 +1. Since this is the first arrival, the 
second time data N.sub.2 becomes 1. Transfer is made to the next frequency 
decision step 305 for determining whether the second time data N.sub.2 is 
larger than 2 or not. Since the second time data N.sub.2 is 1 at this 
time, the decision becomes "No", followed by transfer to the caution 
indication voice generation step 306. At the caution indicating voice 
generation step 306, the overheat caution in the form of voice data stored 
in the predetermined region of the read only memory 6 is supplied to the 
digital voice synthesizer 15 sequentially at repetitive intervals of 
several milliseconds, thus completing one overheat indication operational 
routine. In this way, the voice "Take care of overheat" is issued from the 
speaker 18. 
When it proceeds again to the overheat indication operational routine, the 
second time data N.sub.2 to be added to the addition step 304 in FIG. 4 
takes the value of 2, and the decision at the frequency decision step 305 
becomes "No", thus it proceeds to the caution indicating voice generation 
step 306. As a result, the voice "Take care of overheat" is again produced 
from the speaker 18. When it proceeds further again to the overheat 
indication operational routine, the second time data N.sub.2 to be added 
at the addition step 304 becomes 3, and therefore the decision at the 
frequency decision step 305 becomes "Yes". Transfer is thus made to the 
caution flag cancel step 307 to cancel the caution flag, thus completing 
one operational process of the overheat indication operational routine. 
From the next cycle, the decision becomes "No" when it proceeds to the 
caution flag of FIG. 4 in the overheat indication operational routine, and 
it proceeds to the warning flag decision step 308 where the decision 
becomes "No" and one operational process of the overheat indication 
operational routine is completed through the voice reset signal supply 
step 315. 
In the above-mentioned repetition of the operational processes, the 
interruption operational process of FIG. 5 is executed each time of 
generation of the 1-minute pulse from the timer circuit 13. That is, when 
the temperature of the cooling water rises gradually, the operational 
process is started from the interruption start step 401, and it proceeds 
to the first time flag decision step 410 through the water temperature 
input step 402, the read-out step 403, the change calculation step 404, 
the first change decision step 405 and the second change decision step 
406. Since the first time flag is cancelled, the decision at the step 410 
becomes "No", followed by the advance to the return step 409 through the 
storage step 408, thus completing one operational process. 
If the temperature of the cooling water increases rapidly in the 
above-mentioned interruption operational process, and the amount of change 
R.sub.T determined at the change calculation step 404 exceeds the 
predetermined value B, the decision of the second change decision step 406 
to which it proceeds through the first change decision step 405 becomes 
"Yes", followed by advance to the warning flag setting step 407 where a 
warning flag is set, so that the main routine is restored through the 
storage step 408 and the return step 409. 
When it proceeds to the warning flag setting step 308 in FIG. 4 of the 
overheat indication operational routine in the main routine, the decision 
at the step 308 becomes "Yes" since the warning flag is set already, 
followed by transfer to the addition step 309 thereby to add 1 to the 
third time frequency data N.sub.3 (N.sub.3 =N.sub.3 +1). Under this 
condition, since the third frequency data N.sub.3 is set at 0 by initial 
setting, the third time data N.sub.3 which is updated by addition becomes 
1. Thus the decision at the next frequency step 310 becomes "No", and 
advance is made to the yellow indication step 311. At the yellow 
indication step 311, a set signal is supplied to a related first flip-flop 
in order to turn on the yellow lamp of the indicator 14, followed by 
transfer to the warning voice generation step 312. At the warning voice 
generation step 312, the voice data on the overheat warning indication 
stored in a predetermined area of the read only memory 6 is supplied 
sequentially to the digital voice synthesizer 15 in repetitive cycles of 
several milliseconds. In this way, one operational process of the overheat 
indication operational routine is completed. As a result, the letters of 
the warning against overheat in the indicator 14 are lit in yellow, and 
the speaker 18 produces a voice "Warn against overheat". 
When it proceeds again to the overheat indication operational routine, the 
third time frequency data N.sub.3 which is added at the addition step 309 
in FIG. 4 becomes 2, and the decision at the frequency decision step 310 
becomes "No", therefore, transfer is made to the warning indication voice 
generation step 312 through the yellow indication step 311. Then, the 
voice "Warn against overheat" is again generated from the speaker 18. 
Further, when it proceeds again to the overheat indication operational 
routine, the third time data N.sub.3 which is added at the addition step 
309 in FIG. 4 becomes 3, therefore, the decision at the number of time 
decision step 310 becomes "Yes". The transfer is made to the warning flag 
cancel step 313 to cancel the warning flag, followed by transfer to the 
frequency reset step 314 thereby to set the third time data N.sub.3 at 
zero, thus completing one operational process of the overheat indication 
operational routine. From the next cycle of operation, the decision at the 
warning flag decision step 308 reached through the caution flag decision 
step 301 in FIG. 4 becomes "No", and one operational process of the 
overheat indication operational routine is completed through the voice 
reset signal supply step 315. 
When the temperature of the cooling water further increases up to 
115.degree. C., the water temperature data T applied and stored at the 
water temperature input step 101 of FIG. 2 takes a value higher than 
115.degree. C. Thus when it proceeds to the second water temperature 
decision step 201 of FIG. 3, the decision thereof becomes "Yes" followed 
by transfer to the .beta. level conversion step 202. At the .beta. level 
conversion step 202, the decision level .beta. is converted into a 
predetermined value such as a value corresponding to 110.degree. C. in 
order to provide a hysteresis to the decision at the second water 
temperature decision step 201. Advance is made to the addition step 203 
where 1 is added to the first frequency data N.sub.1 (N.sub.1 =N.sub.1 
+1). Since it is the first arrival to the step, the first time data 
N.sub.1 takes the value of 1. Thus the decision at the next number of 
times decision step 204 becomes "No", followed by transfer to the yellow 
indication cancel step 205. A reset signal is supplied to the first 
flip-flop for the yellow lamp of the indicator 14, followed by transfer to 
the red indication step 206 for supplying a set signal to the second 
flip-flop for the red lamp in the indicator 14, further followed by 
transfer to the overheat indication voice generating step 207. At the 
overheat indication voice generation step 207, the voice data for overheat 
indication stored in the predetermined area of the read only memory 6 are 
supplied sequentially to the digital voice synthesizer 15 at intervals of 
several milliseconds. And transfer is made to the caution flag cancel step 
209 thereby to cancel the caution flag, and also the transfer is made to 
the warning flag cancel step 210 thereby to cancel the warning flag, thus 
completing one operational process of the overheat indication operational 
routine. As a result, the letters warning the operator of overheat is lit 
in red at the indicator 14, and the voice "overheated" is issued from the 
speaker 18. 
Upon rearrival at the overheat indication operat operational routine, the 
first time data N.sub.1 which is added at the addition step in FIG. 3 
becomes 2, and the decision of the frequency decision step 204 becomes 
"No", Therefore, transfer is made to the yellow indication cancel step 
205, the red indication step 206, the overheat indication voice generation 
step 207, the caution flag cancel step 209 and the warning flag cancel 
step 210. Then the voice "overheated" is generated from the speaker 18 
again. When the overheat indication operational routine is reached in the 
third or subsequent cycle, the first time data N.sub.1 which is added at 
the addition step 203 becomes 3 or more, therefore, the decision at the 
frequency decision step 204 becomes "Yes", followed by transfer to the 
voice reset signal supply step 208 whereby a reset signal is supplied to 
the D flip-flop 16. Thus one operational process of the overheat 
indication operational routine is completed through the caution flag 
cancel step 209 and the warning flag cancel step 210. 
In the case where the temperature of the cooling water decreases below 
110.degree. C. during the idling of the automobile engine or the like in 
subsequent cycles of operational process, the water temperature data T 
stored at the water temperature input step 101 in FIG. 2 is reduced to a 
value lower than 110.degree. C. Consequently, upon arrival at the second 
water temperature decision step 201 in FIG. 3, the decision thereof 
becomes "No", followed by transfer to the .beta. level conversion cancel 
step 211 thereby to restore the decision level .beta. to a value 
corresponding to 115.degree. C. Advance is then made to the number of 
times reset step 212 where the first time data N.sub.1 is reset, followed 
by transfer to the red indication cancel step 213, so that a reset signal 
is supplied to the second flip-flop for turning on the red lamp of the 
indicator 14. Thus through the overheat and warning operational routine 
300, one operational process is completed. The indicator 14 fails to 
indicate anything by light and informs the passenger or driver of the fact 
that the overheated condition has ceased. 
When the temperature of the cooling water decreases to become lower than 
85.degree. C., the water temperature data T applied and stored at the 
water temperature input step 101 in FIG. 2 takes a value lower than 
85.degree. C. Therefore, the decision at the first water temperature 
decision step 102 becomes "No", followed by advance to the reset flag 
decision step 109, so that the decision at the step 109 becomes "Yes" 
since the reset flag has thus far been set. Advance is made to the .alpha. 
level conversion cancel step 110 thereby to restore the decision level 
.alpha. to a value corresponding to 90.degree. C. Advance is made further 
to the reset signal supply step 111, thus supplying a reset signal to the 
flip-flop of the timer circuit 13 in order to stop the counting operation 
threof, followed by transfer to the set flag setting step 112 thereby to 
set a set flag. Then advance is made to the reset flag cancel step 113 to 
cancel the reset flag, followed by transfer to the yellow indication 
cancel step 114 so that a reset signal is supplied to the first flip-flop 
of the indicator 14, thus completing one operational process of the 
overheat indication operational routine. As a result, the counting 
operation of the timer circuit 13 stops, and the monitoring of the change 
in the cooling water temperature by the interruption routine of FIG. 5 is 
suspended. The next and subsequent cycles of overheat indication 
operational routine are such that transfer is made from the water 
temperature input step 101 to the first water temperature decision step 
102. Since the water temperature is lower than 90.degree. C., the decision 
at the step 102 becomes "No", followed by transfer to the reset flag 
decision step 109, where the decision becomes "No" since the reset flag is 
cancelled, thus completing the particular operational process. 
In the generation of the voice indicating the overheated condition as 
described above from the speaker 18, when the driver recognizes the voice 
and turns on the stop switch 11 in order to stop the generation of the 
voice, the signal change from the stop switch 11 causes the output of the 
D flip-flop 16 to change to "high" level, and the relay contact of the 
relay circuit 17 is opened to stop the transmission of the voice from the 
digital voice synthesizer 15 to the speaker 18. Thus, no voice is 
generated from the speaker 18. After stoppage of the voice generation, a 
reset signal is supplied to the D flip-flop 16 at the voice reset signal 
supply step 208 or 315, therefore, the output of the D flip-flop 16 is 
again reduced to "low" level, thus reclosing the relay contact of the 
relay circuit 17. 
A general configuration of a second embodiment of the present invention is 
shown in FIG. 6. In the second embodiment, the car speed sensor 10 
provided in the first embodiment of FIG. 1 is lacking and is replaced by a 
demand switch 19. The output of the demand switch 19 is connected to the 
input-output circuit 8 so that the on-off signal of the demand switch 19 
is applied to the input-output circuit 8. Those component elements in FIG. 
6 which are similar to those in the embodiment of FIG. 1 are shown by 
similar reference numerals. 
The second embodiment is different from the first embodiment in that while 
a caution voice is generated by the car speed sensor 19 upon detection of 
the fact that the car speed is reduced to zero in the first embodiment, a 
caution voice signal is generated upon detection of the fact that the 
demand switch 19 has been turned on in the second embodiment. The 
operation of the second embodiment is identical to that of the first 
embodiment except the fact that in the second embodiment, a caution signal 
is generated not upon detection of the car speed of zero but in response 
to the turning on of the demand switch 19. An operational flowchart of the 
overheat caution and warning operational routine for the second embodiment 
is shown in FIG. 7. In the flowchart of FIG. 7, as compared with that of 
FIG. 4, the car speed input step 302 is eliminated, and in place of the 
step 303 for deciding the car speed of zero, the demand switch on decision 
step 316 is added, the remainder being the same as FIG. 4. At the demand 
switch on decision step 316, it is decided whether the signal level has 
risen in response to the turning on of the demand switch 19 or not, and if 
it has risen, advance is made to the addition step 304. 
In the above described embodiments, when the temperature of the cooling 
water exceeds 90.degree. C., the degree of change of the water temperature 
is monitored at intervals of one minute on the basis of the water 
temperature signal from the cooling water temperature sensor 9. When the 
degree of change reaches a predetermined value A, a caution of overheat is 
issued by voice when the car has stopped; while when the degree of change 
of the water temperature reaches a predetermined value B (B&gt;A), an 
indication warning against the overheated condition is made by voice 
regardless of the driving condition of the car. As an alternative method, 
the above-mentioned system of caution and warning may be applied to other 
abnormal conditions than the overheat. For instance, four air pressure 
sensors may be provided for proportionately detecting the air pressure of 
the four tires of a car, whereby it is decided that the air pressure of 
one of the four tires is reduced below a predetermined level in response 
to signals from the four air pressure sensors. From the time of this 
decision, the degree of change of the air pressure of the tires is 
monitored, and when this degree of change reaches a predetermined value A 
(within a range not affecting the driving of the car), a caution of the 
reduced air pressure is indicated by voice upon stoppage of the car. When 
the degree of air pressure change reaches a predetermined value B (B&gt;A), 
on the other hand, a warning of the reduced air pressure is issued by 
voice regardless of the driving conditions of the car. As another 
alternative, the invention may be used for the purpose of forecasting a 
battery voltage, the engine oil condition or a lamp disconnection or for 
monitoring all of these. 
In the above-described embodiments, a voice is synthesized by a digital 
voice synthesizer on the basis of the voice data supplied from the read 
only memory 6 storing the voice data through the input-output circuit 8 
and the voice is issued from the speaker 18. Instead of this system, the 
digital voice synthesizer 15 may contain a read only memory for storing 
the voice data, and the first address of the voice generating area of the 
read only memory is designated by the microcomputer, so that the voice 
data in the addresses following the first address are read out 
sequentially to synthesize the voice, thus shortening the time of 
operation of the microcomputer. 
The above-described embodiments comprise the digital voice synthesizer 15 
and the speaker 18, but these component elements may be replaced by a 
magnetic tape for storing voice data on the indication of abnormal 
conditions, and a circuit for searching a predetermined area of the 
magnetic tape and reproducing the voice data in that particular area. 
Also, the microcomputer used as operational processing means may be 
replaced by a hard logic construction including electronic circuits. 
Furthermore, in place of the stop switch 11 for stopping the voice 
generation temporarily, means may be used for recognizing the voicing of 
the word "stop" by the driver or a passenger for provisional stoppage of 
voice generation. 
In the first embodiment mentioned above, a voice of caution is generated 
when the car speed signal from the car speed sensor 10 reaches zero 
indicating the car stoppage. The car speed signal may not necessarily be 
zero but a low value approximate to zero. 
Further, the decision on the stoppage of the car may be made on the basis 
of the fact that the brake is kept applied for longer than a predetermined 
length of time.