Abstract: A method of detecting a decrease in tire air pressure includes calculating tire rotation information obtained from the wheel tires; computing a first determination value showing a difference between the sums of the wheel rotation information of pairs of wheel tires on two diagonal lines and a second determination value showing a difference between the sum of the wheel rotation information of right wheel tires and the sum of the wheel rotation information of left wheel tires; assuming the computed first and second determination values as points on orthogonal coordinates; determining position of tire(s) having a decreased pressure based on the argument of the points on the polar coordinates; and comparing the moving radii of the points on the polar coordinates with a predetermined threshold value to thereby determine a decrease in tire air pressure.

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 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 method of detecting a decrease in tire air pressure based on wheel rotation information obtained from tires attached to a 4-wheel vehicle.

Abstract: An object is to provide a method capable of reducing calculation number of times for obtaining a primary regression line of a slip ratio and acceleration, and detecting a decrease in internal pressure of tires with high accuracy even in the case where is no evenness in a road surface.

Abstract: A method of judging the load distribution of a vehicle without providing a specific load sensor on a vehicle is characterized in that the load distribution by the every wheel of a vehicle or the load distribution by every axle is judged by comparing the result of comparing the calculation value of the rotational speeds of wheels in the predetermined two combinations of wheels with the result of comparing the calculation value of the rotational speeds of wheels in the fore-mentioned predetermined two combinations of wheels at a predetermined load when the vehicle is under brakeage.

Abstract: A method for detecting decompression of tires based on the rotational speed of wheels mounted on a vehicle, comprising the steps of: detecting the rotational speed of each of the above-mentioned wheels, determining the speed against ground of the vehicle, calculating the speed information of a fixed wheel from the rotational speeds of said wheels, calculating the judgment value of the wheel position by comparing the speed information of the wheels with the speed against ground of the vehicle, comparing the judgment value of the wheel position with the basis value of the wheel position obtained by preliminarily comparing the speed against ground of the vehicle with the speed information of the wheels at prescribed inner pressure, and judging decompression of tires based on relation between the comparison value of the basis value with the judgment value and a fixed threshold. A region of judging decompression of tires can be broadened and the accuracy of reduced pressure judgment can be improved.

Abstract: A method for detecting decompression of tires based on the rotational speed of wheels mounted on a vehicle, comprising the steps of: detecting the rotational speed of each of the above-mentioned wheels, determining the speed against ground of the vehicle, calculating the speed information of a fixed wheel from the rotational speeds of said wheels, calculating the judgment value of the wheel position by comparing the speed information of the wheels with the speed against ground of the vehicle, comparing the judgment value of the wheel position with the basis value of the wheel position obtained by preliminarily comparing the speed against ground of the vehicle with the speed information of the wheels at prescribed inner pressure, and judging decompression of tires based on relation between the comparison value of the basis value with the judgment value and a fixed threshold. A region of judging decompression of tires can be broadened and the accuracy of reduced pressure judgment can be improved.

Abstract: An object is to provide a method capable of reducing calculation number of times for obtaining a primary regression line of a slip ratio and acceleration, and detecting a decrease in internal pressure of tires with high accuracy even in the case where is no evenness in a road surface.

Abstract: A method for detecting decompression of tires based on the rotational speed of wheels mounted on a vehicle, comprising the steps of: detecting the rotational speed of each of the above-mentioned wheels, determining the speed against ground of the vehicle, calculating the speed information of a fixed wheel from the rotational speeds of said wheels, calculating the judgment value of the wheel position by comparing the speed information of the wheels with the speed against ground of the vehicle, comparing the judgment value of the wheel position with the basis value of the wheel position obtained by preliminarily comparing the speed against ground of the vehicle with the speed information of the wheels at prescribed inner pressure, and judging decompression of tires based on relation between the comparison value of the basis value with the judgment value and a fixed threshold. A region of judging decompression of tires can be broadened and the accuracy of reduced pressure judgment can be improved.

Abstract: A judgment whether a decrease in tire air-pressure occurs or not is performed by a process comprising the steps of: detecting information on wheel rotational velocities of tires; obtaining a judgment value for decrease in tire air-pressure based on relative comparison between the detected information on wheel rotational velocities; storing the judgment value(s) into an average preparation buffer BF; obtaining an average value of the judgment value(s) stored in the average preparation buffer BF when the vehicle stops; writing the average value and the number of the judgment values into a nonvolatile memory 2e; expanding the average value written in the nonvolatile memory 2e into the average preparation buffer BF in duplicate corresponding to the number of the judgment values after the start of a drive of the vehicle; and calculating an average value of a prescribed number of judgment values stored in the average preparation buffer BF so as to compare the average value with a threshold value.

Abstract: A detection method of reducing the air pressure of tires based on the rotational speed of wheels mounted on a vehicle. The method includes steps of: detecting the rotational speed of each of the wheels; storing the rotational speed of wheels; determining a judgment value of decompression of tires based on the relative comparison of the rotational speed; storing the judgment value in a non-volatile memory; determining an average value obtained by a moving average of a certain number of the judgment value; and judging decompression of tires by comparing the average value with a threshold. Decompression of tires can be detected even if the traveling of a vehicle is repeated for a short time and the chance of judging the reduced pressure of tires is magnified to be able to enhance the safety of vehicle traveling.

Abstract: A judgment whether a decrease in tire air-pressure occurs or not is performed by a process comprising the steps of: detecting information on wheel rotational velocities of tires; obtaining a judgment value for decrease in tire air-pressure based on relative comparison between the detected information on wheel rotational velocities; storing the judgment value(s) into an average preparation buffer BF; obtaining an average value of the judgment value(s) stored in the average preparation buffer BF when the vehicle stops; writing the average value and the number of the judgment values into a nonvolatile memory 2e; expanding the average value written in the nonvolatile memory 2e into the average preparation buffer BF in duplicate corresponding to the number of the judgment values after the start of a drive of the vehicle; and calculating an average value of a prescribed number of judgment values stored in the average preparation buffer BF so as to compare the average value with a threshold value.

Abstract: It is the purpose of the present invention to provide a method of judging the load distribution of a vehicle without providing a specific load sensor on a vehicle. The method for judging the load distribution of a vehicle of the present invention is characterized in that the load distribution by the every wheel of a vehicle or the load distribution by every axle is judged by comparing the result of comparing the calculation value of the rotational speeds of wheels in the predetermined two combinations of wheels with the result of comparing the calculation value of the rotational speeds of wheels in the fore-mentioned predetermined two combinations of wheels at a predetermined load when the vehicle is under brakeage.

Abstract: A detection method of reducing the air pressure of tires based on the rotational speed of wheels mounted on a vehicle. The method includes steps of: detecting the rotational speed of each of the wheels; storing the rotational speed of wheels; determining a judgment value of decompression of tires based on the relative comparison of the rotational speed; storing the judgment value in a non-volatile memory; determining an average value obtained by a moving average of a certain number of the judgment value; and judging decompression of tires by comparing the average value with a threshold. Decompression of tires can be detected even if the traveling of a vehicle is repeated for a short time and the chance of judging the reduced pressure of tires is magnified to be able to enhance the safety of vehicle traveling.

Abstract: A method for detecting decrease in tire air-pressure in which decrease in internal pressure of a tire is detected on the basis of rotational information obtained from tires attached to a vehicle. The method includes the steps of: detecting rotational information of the respective tires; storing the rotational information of the respective tires; obtaining a slip rate between the tires and a road surface during running; comparing the slip rate with a slip rate which has been preliminarily obtained when at normal internal pressure; and judging simultaneous decompression of two wheel tires of both front wheels or simultaneous decompression of two wheel tires of both rear wheels on the basis of a relationship between a value obtained through comparison of the two slip rates and a specified threshold. It is possible to judge simultaneous decompression of two wheel tires of both front wheels or wheel two tires of both rear wheels.

Abstract: A method for detecting decompression of tires based on the rotational speed of wheels mounted on a vehicle, comprising the steps of: detecting the rotational speed of each of the above-mentioned wheels, determining the speed against ground of the vehicle, calculating the speed information of a fixed wheel from the rotational speeds of said wheels, calculating the judgment value of the wheel position by comparing the speed information of the wheels with the speed against ground of the vehicle, comparing the judgment value of the wheel position with the basis value of the wheel position obtained by preliminarily comparing the speed against ground of the vehicle with the speed information of the wheels at prescribed inner pressure, and judging decompression of tires based on relation between the comparison value of the basis value with the judgment value and a fixed threshold. A region of judging decompression of tires can be broadened and the accuracy of reduced pressure judgment can be improved.

Abstract: A method for detecting decrease in tire air-pressure in which decrease in internal pressure of a tire is detected on the basis of rotational information obtained from tires attached to a vehicle. The method includes the steps of: detecting rotational information of the respective tires; storing the rotational information of the respective tires; obtaining a slip rate between the tires and a road surface during running; comparing the slip rate with a slip rate which has been preliminarily obtained when at normal internal pressure; and judging simultaneous decompression of two wheel tires of both front wheels or simultaneous decompression of two wheel tires of both rear wheels on the basis of a relationship between a value obtained through comparison of the two slip rates and a specified threshold. It is possible to judge simultaneous decompression of two wheel tires of both front wheels or wheel two tires of both rear wheels.

Abstract: An apparatus for alarming decrease in tire air-pressure comprising: a rotational information detecting means for detecting rotational information of the respective tires; a rotational information memory means; a judged value calculating means for calculating judged values based on the rotational information; a judged value memory means; a transition calculating means for calculating transition of the judged values based on the stored judged values; a judging means for determining a decrease in tire air-pressure; and an alarming means for issuing preliminary alarm prior to issuing a predetermined alarm for informing decrease in internal pressure in case the judged value tends to move to exceed a predetermined threshold. It is possible to appropriately inform the driver of the vehicle of a decompressed condition of a tire for making the driver drive safely.

Abstract: An apparatus for alarming decrease in tire air-pressure comprising: a rotational information detecting means for detecting rotational information of the respective tires; a rotational information memory means; a judged value calculating means for calculating judged values based on the rotational information; a judged value memory means; a transition calculating means for calculating transition of the judged values based on the stored judged values; a judging means for determining a decrease in tire air-pressure; and an alarming means for issuing preliminary alarm prior to issuing a predetermined alarm for informing decrease in internal pressure in case the judged value tends to move to exceed a predetermined threshold. It is possible to appropriately inform the driver of the vehicle of a decompressed condition of a tire for making the driver drive safely.