Abstract: A system for detecting deflated tires by making a relative comparison among rotation speeds of tires attached to a vehicle. The system includes a rotation speed information detection means for detecting rotation speed information of the tires; a rotation speed calculation means for calculating rotation speeds of the tires; and a determination means for determining deflated tires by comparing a decreased pressure determination value using the calculated rotation speeds with a predetermined threshold value. The determination means determines that the vehicle is going straight when it is found, with regard to factors composed of a lateral G, a yaw rate, and a steering angle of the vehicle, at least two of the factors including the yaw rate show that a difference between the maximum value and the minimum value at a predetermined time is lower than a predetermined value, thereby detecting deflated tires.

Abstract: A system detects deflated tires based on a resonance frequency of tires with a vehicle and a relative comparison value of rotation speeds of the tires. The system includes: a rotation information detection means for detecting rotation information of the tires; a rotation speed calculation means for calculating rotation speeds of the tires; a resonance frequency assumption means for assuming a resonance frequency of the tires; and a determination means for detection of deflated tires using a decreased pressure determination index calculated by a relative comparison of the rotation speeds of the tires and the resonance frequency. The determination means is so configured as to reduce the second threshold to be compared with the decreased pressure determination index to a value equal to or higher than 1% and equal to or lower than 90% and to detect deflated tires when the decreased pressure determination index exceeds the reduced threshold.

Abstract: An apparatus for detecting a decrease in air pressure of a tire attached to a vehicle includes a rotation speed detection means for periodically detecting rotation speeds of tires of respective wheels of the vehicle; a rotation wheel speed ratio calculation means for calculating a rotation wheel speed ratio between front wheels and rear wheels of the vehicle; a wheel torque calculation means for calculating a wheel torque of the vehicle; an initialization means for obtaining a relation at a normal internal pressure between the wheel torque and the rotation wheel speed ratio; a comparison means for comparing the rotation wheel speed ratio with the rotation wheel speed ratio at a normal internal pressure obtained from the wheel torque and the relation; and a determination means for correcting the comparison result by a front-to-rear direction acceleration and determining whether there is a tire having a decreased air pressure or not.

Abstract: A system detects deflated tires based on a resonance frequency of tires with a vehicle and a relative comparison value of rotation speeds of the tires. The system includes: a rotation information detection means for detecting rotation information of the tires; a rotation speed calculation means for calculating rotation speeds of the tires; a resonance frequency assumption means for assuming a resonance frequency of the tires; and a determination means for detection of deflated tires using a decreased pressure determination index calculated by a relative comparison of the rotation speeds of the tires and the resonance frequency. The determination means is so configured as to reduce the second threshold to be compared with the decreased pressure determination index to a value equal to or higher than 1% and equal to or lower than 90% and to detect deflated tires when the decreased pressure determination index exceeds the reduced threshold.

Abstract: A system for detecting deflated tires by making a relative comparison among rotation speeds of tires attached to a vehicle. The system includes a rotation speed information detection means for detecting rotation speed information of the tires; a rotation speed calculation means for calculating rotation speeds of the tires; and a determination means for determining deflated tires by comparing a decreased pressure determination value using the calculated rotation speeds with a predetermined threshold value. The determination means determines that the vehicle is going straight when it is found, with regard to factors composed of a lateral G, a yaw rate, and a steering angle of the vehicle, at least two of the factors including the yaw rate show that a difference between the maximum value and the minimum value at a predetermined time is lower than a predetermined value, thereby detecting deflated tires.

Abstract: An apparatus includes an acceleration calculation means for calculating, based on rotation speed information obtained from a rotation speed detection means, accelerations of the respective tires; an acceleration variation calculation means for calculating acceleration variations of the tires; a comparison means for comparing the acceleration variations; a presumption means for presuming a pressure decrease of a tire; an examination means for identifying, based on the tire rotation speed information, a tire having a rotation speed that is higher than the rotation speeds of the other tires or that is lower than a predetermined criterion; and a determination means for determining, when a tire identified by the presumption means is identical with a tire identified by the examination means, a pressure decrease of the tire.

Abstract: An apparatus includes a rotating wheel speed ratio calculation means for calculating, based on rotation velocity information, a rotating wheel speed ratio between front wheels and rear wheels of the vehicle; a wheel torque calculation means for calculating a wheel torque of the vehicle; an initialization means for obtaining a relation at a normal internal pressure between the wheel torque and the rotating wheel speed ratio between the front wheels and the rear wheels; a storage means for storing the relation obtained; a comparison means for comparing the rotating wheel speed ratio obtained by the rotating wheel speed ratio calculation means with the rotating wheel speed ratio at a normal internal pressure obtained from the wheel torque obtained by the wheel torque calculation means and the relation; and a judgment means for judging whether a tire air pressure is decreased or not based on a comparison result.

Abstract: An apparatus for detecting a decreased air pressure of a tire includes an acceleration calculation circuit for calculating, based on rotation velocity information of tires of respective wheels of a vehicle; an acceleration variation calculation circuit for calculating acceleration variations of the respective tires; a comparison circuit for comparing the acceleration variations of the respective tires; an estimation component for estimating, when a comparison result of the comparison shows that an acceleration variation of a certain tire is greater than acceleration variations of the other tires, a decrease in air pressure of the certain tire; a test circuit for determining a tire having a rotation velocity that is faster than the rotation velocities of the other tires or that is further slower than a predetermined reference; and a judgment circuit for judging, when a certain tire identified by the estimation is identical with the tire identified by the test, a decrease in air pressure of the certain tire.

Abstract: An apparatus for detecting a decrease in air pressure of a tire attached to a vehicle.

Abstract: An apparatus includes an acceleration calculation means for calculating, based on rotation speed information obtained from a rotation speed detection means, accelerations of the respective tires; an acceleration variation calculation means for calculating acceleration variations of the tires; a comparison means for comparing the acceleration variations; a presumption means for presuming a pressure decrease of a tire; an examination means for identifying, based on the tire rotation speed information, a tire having a rotation speed that is higher than the rotation speeds of the other tires or that is lower than a predetermined criterion; and a determination means for determining, when a tire identified by the presumption means is identical with a tire identified by the examination means, a pressure decrease of the tire.

Abstract: It is the purpose of the present invention to provide a method, apparatus and program for alarming abnormality in tire air-pressure capable of precisely detecting decrease in tire air-pressure even at actuation of air suspension in a vehicle equipped with air suspensions. The present invention discloses a method for alarming abnormality in tire air-pressure informing decrease in tire air-pressure mounted on a vehicle, comprising a step of judging whether loads applied on respective tires are changed by the influence of air suspensions based on the difference of the heights of strokes between left wheel and right wheel in a vehicle equipped with the air suspensions and affect the rotational wheel speeds of tires or not, and increasing threshold for carrying out the judgment of decrease in tire air-pressure when the air suspensions provide influence.

Abstract: The apparatus for detecting a decreased air pressure of a tire includes an acceleration calculation means for calculating, based on rotation velocity information of tires of respective wheels of a vehicle; an acceleration variation calculation means for calculating acceleration variations of the respective tires; a comparison means for comparing the acceleration variations of the respective tires; an estimation means for estimating, when a comparison result of the comparison means shows that an acceleration variation of a certain tire is greater than acceleration variations of the other tires, a decrease in air pressure of the certain tire; a test means for determining a tire having a rotation velocity that is faster than the rotation velocities of the other tires or that is further slower than a predetermined reference; and a judgment means for judging, when a certain tire identified by the estimation means is identical with the tire identified by the test means, a decrease in air pressure of the certain tir

Abstract: An apparatus includes a rotating wheel speed ratio calculation means for calculating, based on rotation velocity information, a rotating wheel speed ratio between front wheels and rear wheels of the vehicle; a wheel torque calculation means for calculating a wheel torque of the vehicle; an initialization means for obtaining a relation at a normal internal pressure between the wheel torque and the rotating wheel speed ratio between the front wheels and the rear wheels; a storage means for storing the relation obtained; a comparison means for comparing the rotating wheel speed ratio obtained by the rotating wheel speed ratio calculation means with the rotating wheel speed ratio at a normal internal pressure obtained from the wheel torque obtained by the wheel torque calculation means and the relation; and a judgment means for judging whether a tire air pressure is decreased or not based on a comparison result.

Abstract: The present invention provides an apparatus, method and program for detecting abnormality in tire air-pressure which allow detecting abnormality in tire air-pressure even if pressure in a tire is completely zero. The apparatus for alarming abnormality in tire air-pressure includes means of (1) calculating the acceleration variations of respective tires from accelerations of the tires calculated by rotational wheel velocities; (2) comparing the calculated acceleration variations of the respective tires; and (3) detecting air-pressure in a tire is abnormal when the acceleration variation of the tire is larger than the acceleration variations of the remaining tires as a result of comparison.

Abstract: An object of the present invention is to provide a device for detecting as to whether or not the heterogeneous tires are set on the right and left wheels, respectively, and accurately detecting the loss of the pneumatic pressure in the tire, even when heterogeneous tires are set on the right and the left wheels, respectively.

Abstract: The present invention provides an apparatus, method and program for alarming abnormality in tire air-pressure which prevent the issuance of an erroneous alarm and thus determine abnormality in tire air-pressure even when a rotational velocity of the tire changes by causes other than a decrease in an air pressure. An apparatus for alarming abnormality in tire air-pressure decrease detects a change in a relationship between wheel velocities of front wheel tires and those of rear wheel tires, and replaces a relationship between the wheel velocities of the front wheel tires and those of the rear wheel tires with a relationship between wheel velocities of front wheel tires and those of rear wheel tires obtained after the change of the relationship, thereby determining abnormality in air-pressure when the change is detected.

Abstract: The present invention provides an apparatus, method and program for alarming abnormality in tire air-pressure which detects abnormality of a tire even under unusual conditions such as offset load on a vehicle or providing a snow chain on one wheel. The apparatus, method and program for alarming abnormality in tire air-pressure include means of comparing rotational wheel velocities of respective tires provided on a vehicle and detecting whether or not rotational wheel velocity of one wheel is slower than those of other wheels by comparing rotational wheel velocities of respective tires provided on a vehicle.

Abstract: A method, an apparatus and a program for alarming abnormality in tire air-pressure which enables to prevent issuing a erroneous alarm or no alarm when only one tire is replaced with a new tire can be provided. The method of alarming abnormality in tire air-pressure includes a step of detecting whether or not a new tire has been mounted by comparing the difference between determinate values to judge a decrease in air-pressure before and after enlargement of a diameter of the new tire with a set threshold value when solely one tire is replaced with the new tire with the use of a phenomenon that a diameter of a new tire on a vehicle enlarges after running.

Abstract: The subject is to provide a method for alarming a decrease in tire air-pressure that can improve the precision of the reduced pressure judgment and a device thereof and a program for judging the decrease in tire air-pressure. Means for solution is a method for alarming a decrease in tire air-pressure that informs the decrease in tire air-pressure based on the rotational speed obtained from tires loaded on a four-wheeled vehicle, a device thereof and a program thereof, wherein the influence of turning and the influence of acceleration to a lateral direction that are the correction factors of the judged value of the decrease in tire air-pressure are excluded.

Abstract: An apparatus for calculating an initial correction coefficient for correcting rotational angular velocities obtained from outputs of rotational angular velocity detecting means. The apparatus includes a judged value calculating means which calculates a judged value on the basis of the rotational angular velocities; an identifying means which identifies whether the vehicle is performing turning movements at high velocity, straight-ahead running or turning movements at mid/low velocity; and an initial correction coefficient calculating means which obtains an initial correction coefficient when it has been identified by the identifying means that the vehicle is performing straight-ahead running or turning movements at mid/low velocity. It is possible to obtain accurate correction coefficients so that it is possible to accurately detect, for instance, a decrease in tire air-pressure and thus to maintain safe running.