U.S. patent application number 09/945664 was filed with the patent office on 2002-04-18 for apparatus and method for alarming decrease in tire air-pressure.
Invention is credited to Sugisawa, Toshifumi.
Application Number | 20020044051 09/945664 |
Document ID | / |
Family ID | 18755730 |
Filed Date | 2002-04-18 |
United States Patent
Application |
20020044051 |
Kind Code |
A1 |
Sugisawa, Toshifumi |
April 18, 2002 |
Apparatus and method for alarming decrease in tire air-pressure
Abstract
An apparatus for alarming a decrease in tire air-pressure by
using a judged value calculated based on rotational information
obtained from tires fitted to a four-wheeled vehicle. The apparatus
comprises: traveling determining means for determining whether the
vehicle should be stopped at once or the vehicle can still travel
to some extent; vehicle position detecting means; collating means
for collating the detected vehicle traveling position with
positional information on a blowout repairing facility; facility
calling means for calling a nearest blowout repairing facility; and
display means for displaying a route from the vehicle traveling
position to the called facility. The apparatus according to the
present invention can teach the route to the blowout repairing
facility after giving the alarm of the decrease in tire pressure,
thus achieving the repairing of blown-out tire after the safe
traveling.
Inventors: |
Sugisawa, Toshifumi;
(Kobe-shi, JP) |
Correspondence
Address: |
BIRCH STEWART KOLASCH & BIRCH
PO BOX 747
FALLS CHURCH
VA
22040-0747
US
|
Family ID: |
18755730 |
Appl. No.: |
09/945664 |
Filed: |
September 5, 2001 |
Current U.S.
Class: |
340/442 ;
340/444 |
Current CPC
Class: |
B60C 23/00 20130101;
B60C 23/0401 20130101; B60C 23/061 20130101 |
Class at
Publication: |
340/442 ;
340/444 |
International
Class: |
B60C 023/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 5, 2000 |
JP |
2000-269049 |
Claims
What is claimed is:
1. An apparatus for alarming a decrease in tire air-pressure which
alarms the decrease in inner pressure of the tire by using a judged
value calculated based on rotational information obtained from
tires fitted to a four-wheeled vehicle, comprising: traveling
determining means for determining whether the vehicle should be
stopped at once or the vehicle can still travel to some extent when
the decrease in tire air-pressure is judged; vehicle position
detecting means for detecting a vehicle traveling position at the
time of judgment of the decrease in tire air-pressure; collating
means for collating the detected vehicle traveling position with
positional information on a blowout repairing facility, which has
been input previously; facility calling means for calling a nearest
blowout repairing facility being open based on the collation by the
collating means; and display means for displaying a route from the
vehicle traveling position to the called facility, wherein the
vehicle position detecting means, the collating means, the facility
calling means and the display means are started to be operated in
the case where the traveling determining means determines that the
vehicle can still travel to some extent.
2. An apparatus for alarming a decrease in tire air-pressure which
alarms the decrease in inner pressure of the tire by using a judged
value calculated based on rotational information obtained from
tires fitted to a four-wheeled vehicle, comprising: vehicle
position detecting means for detecting a vehicle traveling position
at the time of judgment of the decrease in tire air-pressure;
collating means for collating the detected vehicle traveling
position with positional information on a blowout repairing
facility, which has been input previously; and threshold value
changing means for changing a threshold value of the judgement of
the decrease in inner pressure of the tires according to the
vehicle traveling position.
3. The apparatus of any one of claims 1 to 2, wherein the
positional information on the blowout repairing facility is input
in a navigation system.
4. A method for alarming a decrease in tire air-pressure which
alarms the decrease in inner pressure of the tire by using a judged
value calculated based on rotational information obtained from
tires fitted to a four-wheeled vehicle, comprising the steps of:
detecting a vehicle traveling position at the time of judgment of
the decrease in tire air-pressure; collating the detected vehicle
traveling position with positional information on a blowout
repairing facility, which has been input previously; calling a
nearest blowout repairing facility being open based on the
collation; and displaying a route from the vehicle traveling
position to the called facility, wherein the steps are started to
be performed in the case where it is determined that the vehicle
can still travel to some extent.
5. A method for alarming a decrease in tire air-pressure which
alarms the decrease in inner pressure of the tire by using a judged
value calculated based on rotational information obtained from
tires fitted to a four-wheeled vehicle, comprising the steps of:
detecting a vehicle traveling position at the time of judgment of
the decrease in tire air-pressure; collating the detected vehicle
traveling position with positional information on a blowout
repairing facility, which has been input previously; and changing a
threshold value of the judgement of the decrease in inner pressure
of the tires according to the vehicle traveling position.
6. The method of any one of claims 4 to 5, wherein the method
includes a step of accessing positional information on the blowout
repairing facility input in a computer outside of the vehicle by
means of a communication means capable of communicating with the
outside of the vehicle.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to an apparatus and a method
for alarming a decrease in tire air-pressure and, more
particularly, to an apparatus and a method for alarming a decrease
in tire air-pressure, which can teach a route to a blowout
repairing facility being open and can achieve safe traveling.
[0002] It is most dangerous in case of a tire blowout that a driver
continues traveling without any awareness of the blowout. In view
of this, there has been conventionally known a tire air-pressure
alarming apparatus (DWS) for giving an alarm to a driver about a
decrease in pressure of a tire upon detection of the decrease in
pressure of the tire.
[0003] However, even if the alarming apparatus can detect the tire
blowout so as to prevent an accident, no consideration is given to
repairing of the blown-out tire which is needed at a next step.
[0004] Should a blowout alarm be given during traveling on an
expressway, it is difficult for a driver to judge how far it is to
a next service area or how far the blown-out tire endures
traveling. Therefore, some of drivers might stop their cars on a
road shoulder of the expressway to repair the blown-out tire even
in the case where the blown-out tire could endure traveling to the
next service area. However, it is dangerous to repair the blown-out
tire on the road shoulder of the expressway.
[0005] Furthermore, since a blowout repairing facility being open
is limited in quantity during traveling in, for example, a suburb
of a city in the nighttime, it is difficult for a driver to find
out such a facility at once.
[0006] Moreover, a driver might be exposed to a danger during
repairing a blown-out tire in a region of a low level of
security.
[0007] Consequently, although the conventional apparatus for
alarming the decrease in tire air-pressure can prevent any accident
caused by the blowout, the apparatus cannot at all eliminate the
danger and inconvenience in the case where the driver possibly
repairs the blown-out tire on the road shoulder of the expressway
or in the region of a low level of security.
[0008] In view of the above-described circumstances, an object of
the present invention is to provide an apparatus and a method for
alarming a decrease in tire air-pressure, which can teach a route
to a blowout repairing facility being open and can achieve safe
traveling.
SUMMARY OF THE INVENTION
[0009] In accordance with the present invention, there is provided
an apparatus for alarming a decrease in tire air-pressure which
alarms the decrease in inner pressure of the tire by using a judged
value calculated based on rotational information obtained from
tires fitted to a four-wheeled vehicle, comprising: traveling
determining means for determining whether the vehicle should be
stopped at once or the vehicle can still travel to some extent when
the decrease in tire air-pressure is judged; vehicle position
detecting means for detecting a vehicle traveling position at the
time of judgment of the decrease in tire air-pressure; collating
means for collating the detected vehicle traveling position with
positional information on a blowout repairing facility, which has
been input previously; facility calling means for calling a nearest
blowout repairing facility being open based on the collation by the
collating means; and display means for displaying a route from the
vehicle traveling position to the called facility, wherein the
vehicle position detecting means, the collating means, the facility
calling means and the display means are started to be operated in
the case where the traveling determining means determines that the
vehicle can still travel to some extent.
[0010] In accordance with the present invention, there is further
provided an apparatus for alarming a decrease in tire air-pressure
which alarms the decrease in inner pressure of the tire by using a
judged value calculated based on rotational information obtained
from tires fitted to a four-wheeled vehicle, comprising: vehicle
position detecting means for detecting a vehicle traveling position
at the time of judgment of the decrease in tire air-pressure;
collating means for collating the detected vehicle traveling
position with positional information on a blowout repairing
facility, which has been input previously; and threshold value
changing means for changing a threshold value of the judgement of
the decrease in inner pressure of the tires according to the
vehicle traveling position.
[0011] In accordance with the present invention, there is also
provided a method for alarming a decrease in tire air-pressure
which alarms the decrease in inner pressure of the tire by using a
judged value calculated based on rotational information obtained
from tires fitted to a four-wheeled vehicle, comprising the steps
of: detecting a vehicle traveling position at the time of judgment
of the decrease in tire air-pressure; collating the detected
vehicle traveling position with positional information on a blowout
repairing facility, which has been input previously; calling a
nearest blowout repairing facility being open based on the
collation; and displaying a route from the vehicle traveling
position to the called facility, wherein the steps are started to
be performed in the case where it is determined that the vehicle
can still travel to some extent.
[0012] In accordance with the present invention, there is yet
further provided a method for alarming a decrease in tire
air-pressure which alarms the decrease in inner pressure of the
tire by using a judged value calculated based on rotational
information obtained from tires fitted to a four-wheeled vehicle,
comprising the steps of: detecting a vehicle traveling position at
the time of judgment of the decrease in tire air-pressure;
collating the detected vehicle traveling position with positional
information on a blowout repairing facility, which has been input
previously; and changing a threshold value of the judgement of the
decrease in inner pressure of the tires according to the vehicle
traveling position.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a block diagram illustrating an embodiment of an
apparatus for alarming a decrease in tire air-pressure according to
the present invention;
[0014] FIG. 2 is a block diagram illustrating electric
configuration of the apparatus for alarming a decrease in tire
air-pressure of FIG. 1;
[0015] FIG. 3 illustrates the situation in which the apparatus for
alarming a decrease in tire air-pressure calls a blowout repairing
facility and teaches a route to the facility;
[0016] FIG. 4 is a flowchart illustrating the processing of
displaying the route to a nearest blowout repairing facility being
open after a decrease in pressure is judged; and
[0017] FIG. 5 is a flowchart illustrating the processing of
reducing a threshold value so as to easily give an alarm.
DETAILED DESCRIPTION
[0018] An apparatus and a method for alarming a decrease in tire
air-pressure according to the present invention will be described
below in reference to the accompanying drawings.
[0019] As shown in FIG. 1, an embodiment of an apparatus for
alarming decrease in tire air-pressure according to the present
invention is so designed as to detect whether or not pneumatic
pressures of four tires FL, FR, RL and RR (W.sub.i, i=1.about.4, 1:
front left tire, 2: front right tire, 3: rear left tire, 4: rear
right tire) attached to, for example, a four-wheeled vehicle are
decreased, and is provided with popular rotational information
detecting means 1 respectively provided in connection with each
tire W.sub.i.
[0020] The rotational information detecting means 1 takes the form
of, for example, a wheel speed sensor for measuring a rotational
speed from the number of rotation pulses generated by using an
electromagnetic pickup of the like, or an angular velocity sensor
for measuring a rotational speed from a voltage generated by using
rotation by a dynamo electric. Output of the rotational information
detecting means 1 and a lateral G sensor is applied to a control
unit 2. To the control unit 2, a display device 3 for informing of
the tire W.sub.i having a decreased pneumatic pressure, the display
device 3 being constituted by a liquid crystal display element, a
plasma display element, a CRT or the like, and an initialization
switch 4 capable of being operated by a driver are connected. In
this case, reference numeral 5 denotes a navigation system.
[0021] The control unit 2 includes, as shown in FIG. 2, an I/O
interface 2a required for giving and taking a signal with respect
to an external device, a CPU 2b functioning as a center of a
calculating process, a ROM 2c storing a control operation program
of the CPU 2b and a RAM 2d in which data is temporarily written or
the written data is read at a time when the CPU 2b executes the
control operation.
[0022] The present invention is featured by sharing information
stored in the apparatus for alarming a decrease in tire
air-pressure and information stored in a navigation system.
[0023] The apparatus for alarming a decrease in tire air-pressure
according to the present embodiment includes, for example,
rotational information detecting means for detecting rotational
information on each of tires, memory means for storing therein the
rotational information on each of the tires, calculating means for
calculating a judged value based on the rotational information on
each of the tires, and judging means for judging a decrease in
inner pressure of the tire based on the judged value. The apparatus
further includes traveling determining means for determining
whether a vehicle should be stopped at once or the vehicle can
still travel to some extent when the decrease in tire air-pressure
is judged; vehicle position detecting means for detecting a vehicle
traveling position at the time of the judgment of the decrease in
tire air-pressure; collating means for collating the detected
vehicle traveling position with positional information on a blowout
repairing facility, which has been input previously; facility
calling means for calling a nearest blowout repairing facility
being open based on the collation by the collating means; and
display means for displaying a route from the vehicle traveling
position to the called facility.
[0024] In the present embodiment, the vehicle position detecting
means, the collating means, the facility calling means and the
display means are started to be operated in the case where the
traveling determining means determines that the vehicle can still
travel to some extent.
[0025] That is to say, the apparatus for alarming a decrease in
tire air-pressure is equipped with the function of determining
whether or not the vehicle can reach the nearest blowout repairing
facility based on the judged value used for judging the decrease in
pressure in the apparatus for alarming a decrease in tire
air-pressure or its variation. For example, when the judged value
is moderately varied and it is judged that there is no possibility
of an abrupt burst after the judged value exceeds a predetermined
threshold value and the decrease in pressure is determined, a
driver is guided to the nearest blowout repairing facility. In this
manner, the driver can know a route to the blowout repairing
facility being open and safely drive the vehicle. In contrast, the
driver is called to stop the vehicle in the case where the judged
value is markedly large or the variation is large and there is a
danger of a burst until the driver reaches the nearest blowout
repairing facility. Consequently, the driver can replace the tire
by himself or herself, and further, can make contact with the
nearest blowout repairing facility being open or an on-site service
to have the tire replaced.
[0026] The method for determining whether the vehicle should be
stopped at once or the vehicle can still travel to some extent when
the decrease in tire air-pressure is judged is exemplified as
follows:
[0027] A wheel speed per second of a sampling time is first
captured based on a wheel speed pulse, a judged value of a decrease
in pressure of a tire (DEL) is calculated, the DEL values are
averaged per sampling time, for example, every five seconds in
order to enhance the accuracy of the judgement, past twelve
5-second average values (DEL5) are subjected to processing of
moving averages, and then, the decrease in pressure is judged by
the use of the resultant moving average value (DELAV), resulting in
a judgement (1) or (2) under the following conditions (A) to
(C):
[0028] (A) .vertline.DELAV.vertline..gtoreq.0.1
[0029] (B) .vertline.DEL5.vertline..gtoreq.0.15 occurs four times
in sequence
[0030] (C) .vertline.DEL5.vertline..gtoreq.0.1, and the condition
that an increase in DEL5 is 0.033 or more occurs four times in
sequence
[0031] (1) When the condition (B) or (C) is satisfied, it is judged
that the vehicle should be stopped at once.
[0032] (2) When the condition (A) is satisfied but the conditions
(B) and (C) are not satisfied, it is judged that the pressure is
decreased and the vehicle can still travel to some extent.
[0033] As the vehicle position detecting means can be used a car
navigation device using a GPS antenna or the like.
[0034] As the above-described car navigation device, there can be
used one which detects the traveling position by using an antenna
for a GPS (global positioning system) or the like, inputs map data
on the surroundings of the traveling position into a car navigation
body via a CD-ROM, and displays geographic information on a display
panel or the like through the processing of a map displaying
routine. Furthermore, the car navigation device receives road
information from an outside transmitter such as a beacon or an FM
transmitter installed with respect to a road via a beacon antenna,
and additionally displays the road information on the display panel
or the like through the processing of a displaying routine of the
navigation body. In the case where the above-described car
navigation device is used, the display panel can serve as the
display means.
[0035] As the collating means, there can be used one which stores
the positional information on, for example, the position, service
day and service time of the blowout repairing facility in a CD-ROM
or the like in the form of a database, and collates the positional
information with the detected vehicle traveling position so as to
extract the facility being open based on the current time and
position, or calculates a distance based on the current time and
position so as to make a search for the nearest facility.
[0036] In the present embodiment, the vehicle position detecting
means and the collating means constitute a navigation system 5,
which is mounted on a vehicle, as illustrated in FIG. 3.
[0037] Thus, when the apparatus 6 for alarming a decrease in tire
air-pressure detects a decrease in tire air-pressure, the
navigation system 5 finds the position, searches a nearest blowout
repairing facility 7a being open at that time out of blowout
repairing facilities 7a and 7b which have been previously
registered in the navigation system 5 and at which a blown-out tire
can be repaired, and then, teaches the driver a shortest route to
the facility 7a.
[0038] In addition to the function of searching the position of the
vehicle, information on facilities (such as a location, a service
time, a closing day and a telephone number) in which the blown-out
tire can be repaired (such as a parking area, a service area, a gas
station and a tire shop) has been previously registered in the
navigation system 5. Moreover, it is preferable that a dangerous
region or the like in view of security should be registered as
required.
[0039] In this manner, when the apparatus for alarming the decrease
in tire air-pressure detects the decrease in pressure of the tire,
the apparatus first searches the nearest blowout repairing facility
being open at that time on that day based on the information, and
then, teaches the driver the shortest route to the facility. At the
same time, the apparatus also displays a telephone number or the
like, thereby enabling the driver to make contact with the facility
via a mobile phone or the like.
[0040] If there is no facility being open thereabouts, the
apparatus can display a telephone number of an on-site service.
[0041] The embodiment according to the present invention will be
described with reference to FIGS. 3 and 4. As illustrated in FIG.
3, the apparatus is provided with communication means 8 capable of
communicating with the outside of the vehicle. As the communication
means 8 can be used a radio telephone line such as a PHS, a radio
device in conformance with the radio telephone line or the like.
The communication means 8 makes access to the positional
information on the blowout repairing facility 7a or 7b input in a
computer outside of the vehicle, for example, means such as a host
computer 9 of the VICS (Vehicle Information Communication System)
via the Internet.
[0042] First, as illustrated in FIG. 4, the processing of judging
the decrease in tire pressure of the traveling vehicle is performed
(step S1). The processing of judging the decrease in pressure in
the apparatus for alarming the decrease in tire air-pressure at
that time is performed according to, for example, the following
procedures. After rotational information detecting means 1 outputs
a pulse signal corresponding to the number of revolutions of each
of tires W.sub.i (hereinafter referred to as a wheel speed pulse),
a CPU 2b calculates a rotational angular velocity F.sub.i of each
of the tires W.sub.i per predetermined sampling cycle .DELTA.T
(sec.), for example, per second based on the wheel speed pulse
output from the rotational information detecting means 1.
[0043] Here, since tires W.sub.i are manufactured while
irregularity is present within a specification (initial
difference), the effective rolling radii of the tires W.sub.i
(values each obtained by dividing a distance advancing by one
rotation by 2.pi.) are not necessarily equal even if all of the
tires W.sub.i have ordinary internal pressure. As a result, the
rotational angular velocities F.sub.i of the tires W.sub.i become
irregular. Considering this, a corrected rotational angular
velocity F1.sub.i to cancel the irregularity due to the initial
difference is calculated. To be specific, the respective rotational
angular velocity is corrected as follows:
[0044] F1.sub.1=F.sub.1
[0045] F1.sub.2=mF.sub.2
[0046] F1.sub.3=F.sub.3
[0047] F1.sub.4=nF.sub.4
[0048] Correction coefficients m and n are obtained as
m=F.sub.1/F.sub.2 and n=F.sub.3/F.sub.4 by calculating the
rotational angular velocity F.sub.i under conditions, for example,
that a vehicle is running on a straight road and then obtaining the
coefficients m and n based on the calculated rotational angular
velocity F.sub.i. Based on above F1.sub.i, a vehicle speed V (Vi/4)
is are calculated.
[0049] Further, a pressure reduction judged value (DEL) for
detecting decrease in air-pressure of the tire W.sub.i is to
compare the difference between, for example, two sums of pairs of
front-wheel tires and rear-wheel tires on a diagonal. Specifically,
the sum of signals from one pair of wheels on a diagonal is
subtracted from the sum of signals from the other pair of wheels on
the diagonal, and a ratio of the subtraction result to the average
value of the two sums is obtained from the following formula (1): 1
DEL = 2 .times. { ( V1 + V4 ) - ( V2 + V3 ) V1 + V2 + V3 + V4
.times. 100 % ( 1 )
[0050] Subsequently, as the result of the judgement about the
decrease in pressure, if the decrease in pressure is not judged
(step S2), alarming and route searching are cleared (step S3). In
contrast, if the decrease in pressure is judged (step S2), it is
judged whether the vehicle should be stopped at once since the
judged value signifies an abrupt blowout or the vehicle can still
travel to some extent (step S4). Here, in case of an abrupt
blowout, the driver is alarmed to stop the vehicle at once (step
S5).
[0051] Next, in the case of not an abrupt blowout (step S4), it is
judged whether or not the decrease in pressure is judged by a first
detection of the decrease in pressure (step S6). If the decrease in
pressure is judged by the first detection of the decrease in
pressure, the blowout repairing facility being open is extracted
(step S7). After the blowout repairing facility nearest the current
position is retrieved and searched (steps S8 and S9), the apparatus
displays the route to the nearest blowout repairing facility being
open so as to teach it to the driver (step S10). Here, since there
is a danger of omission of the route search unless the decrease in
pressure is judged by the first detection of the decrease in
pressure in step S6, it is judged whether or not the current route
search is omitted.
[0052] In this manner, the driver can know the route to the blowout
repairing facility being open, and can safely drive.
[0053] An apparatus for alarming a decrease in tire air-pressure in
another preferred embodiment according to the present invention is
provided with threshold value changing means for changing a
threshold value of the judgement of a decrease in tire air-pressure
according to a traveling position of a vehicle.
[0054] In judging the decrease in tire air-pressure judgement of
the decrease in pressure) in the apparatus for alarming the
decrease in tire air-pressure, the threshold value of the judgement
of the decrease in tire air-pressure is set lower than a usual
value by the threshold value changing means during traveling in a
region or a time zone in which it seems to be preferable to give an
alarm indicating the decrease in pressure to the driver earlier
than usual in the case where, for example, there is no blowout
repairing facility being open at that time thereabouts or a vehicle
travels in a region of a low level of security based on information
stored in a navigation system.
[0055] Namely, in order to avoid any situation in which the driver
cannot reach the blowout repairing facility, a blowout alarm is
given earlier than usual during traveling in an area in which the
repairing facility is few in quantity. The apparatus for alarming
the decrease in tire air-pressure judges based on the judged value
whether or not the tire blows, and if its threshold value is too
small, a blowout might be erroneously judged in spite of a normal
inner pressure. Therefore, the threshold value takes a large value
to such a certain extent that no alarm is given with an error
occurring under normal inner pressure.
[0056] However, from the viewpoint of the safeness for the driver,
it is desirable to earlier notify the driver of the possibility of
the decrease in tire pressure even with a fear of an erroneous
alarm during traveling in the area or time zone in which the
repairing facility is few in quantity or in the region of a low
level of security. Consequently, in order to promote early
inspection in the tire repairing facility, the threshold value is
set to a slightly small value so as to easily give an alarm under
the above-described circumstance.
[0057] A further embodiment according to the present invention will
be explained below with reference to FIG. 5. First in step S21, a
blowout repairing facility being open is extracted based on a
current position at an updating timing, for example, once every ten
minutes (step S22), and then, it is retrieved whether or not there
is a blowout repairing facility within a predetermined radius of 30
km from the current position (step S23). As a result of the
retrieval, when there is a blowout repairing facility being open
within a radius of 30 km from the current position (step S24), the
decrease in pressure is judged based on a normal alarm threshold
value at the time of the decrease in tire air-pressure (step S25).
In contrast, if there is no blowout repairing facility being open
within a radius of 30 km from the current position (step S24), the
alarm threshold value at the time of the decrease in tire
air-pressure is set to 0.8 times the normal threshold value since
it seems to be preferable for the driver to give an alarm of the
decrease in pressure earlier than usual (step S26). Thereafter, the
decrease in pressure is judged (step S25). Thus, the driver can be
notified of the judgement of the decrease in pressure earlier than
usual, and therefore, can safely drive.
[0058] Incidentally, in the above-described embodiments, the
information registered in the navigation system can be updated by
loading down latest data from an information terminal such as a
mobile telephone.
[0059] In this manner, the addition of the information registered
in the navigation system to the conventional apparatus for alarming
the decrease in tire air-pressure can provide not only the
apparatus for simply alarming the decrease in tire pressure but
also the information for safely and speedily repairing the
blown-out tire, or can provide higher safeness for the driver by
early giving the alarm according to the traveling region or time
zone so as to avoid such a situation in which the driver cannot
reach the blowout repairing facility.
[0060] As described above, the apparatus for alarming the decrease
in tire air-pressure according to the present invention can teach
the route to the blowout repairing facility after giving the alarm
of the decrease in tire pressure, thus achieving the repairing of
blown-out tire after the safe traveling.
* * * * *