Tire pressure monitoring system

• US 20040260436A1
• Filed: 06/14/2004
• Published: 12/23/2004
• Est. Priority Date: 06/19/2003
• Status: Active Grant

• Current Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Original Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Inventors: Kin, Keiyu
• Granted Patent: US 7,205,886 B2
• Time in Patent Office: Days
• US Class Current: 701/29
• CPC Class Codes: B60C 23/061 by monitoring wheel speed measuring distance traversed on the ground by vehicles G01C22/00
• CPC Class Codes: B60C 23/062 Frequency spectrum analysis of wheel speed signals, e.g. using Fourier transformation

Abstract

A vehicle C is provided with four wheel speed sensors VS (VSfl, VSfr, VSrl, VSrr) (wheel vibration detection means) for detecting wheel speed V (Vfl, Vfr, Vrl, Vrr) at respective four wheels W (left and right front wheels Wfl, Wfr and left and right rear wheels Wrl, Wrr). When the tire pressure is in the normal value, a tire pressure monitoring system 1 prepares vibration frequency reference spectrum data for predetermined vehicle speed bands based on the detection values of each wheel speed sensor VS. The tire pressure monitoring system 1 compares the current vibration frequency spectrum data and the vibration frequency reference spectrum data corresponding to the current vehicle speed band, and determines that the tire is underinflated if the comparison result exceeds a predetermined value.

Claims

1. A tire pressure monitoring system comprising:

a wheel vibration detection means which detects vibrations of a wheel mounted to a vehicle;

a speed detection means which detects wheel speed;

a vibration frequency spectrum data producing means which applies a predetermined converting process to detection values from the wheel vibration detection means and produces vibration frequency spectrum data consisting of vibration frequency and a gain of the vibration frequency caused by a rotation of the wheel;

a vibration frequency reference spectrum data storage means which stores a plurality of vibration frequency reference spectrum data in a manner associated with wheel speed, the vibration frequency reference spectrum data being used as a reference for a case where air pressure of a tire attached to the wheel is a normal value; and

an air pressure determination means which reads the vibration frequency reference spectrum data from the vibration frequency reference spectrum data storage means on the basis of a current wheel speed or a current vehicle speed, compares a pattern of the thus read vibration frequency reference spectrum data with a pattern of current vibration frequency spectrum data produced by the vibration frequency spectrum data producing means, and determines that the tire is underinflated if a comparison result of these patterns exceeds a predetermined value.

2. A tire pressure monitoring system according to claim 1, further comprising means for producing the vibration frequency reference spectrum data at the time of driving the vehicle by means of applying a predetermined converting process to the detection values from the wheel vibration detection means, wherein the produced vibration frequency reference spectrum data is stored in the vibration frequency reference spectrum data storage means in a manner associated with vehicle speed.

3. A tire pressure monitoring system according to claim 1, wherein the wheel vibration detection means is a wheel speed sensor.

4. A tire pressure monitoring system according to claim 2, wherein the wheel vibration detection means is a wheel speed sensor.

5. A tire pressure monitoring system comprising:

a wheel vibration detection means which detects vibrations of a wheel mounted to a vehicle;

a speed detection means which detects the speed of the vehicle;

a vibration frequency spectrum data producing means which applies a predetermined converting process to detection values from the wheel vibration detection means and produces vibration frequency spectrum data consisting of vibration frequency and a gain of the vibration frequency caused by a rotation of the wheel;

a vibration frequency reference spectrum data storage means which stores a plurality of vibration frequency reference spectrum data in a manner associated with vehicle speed, the vibration frequency reference spectrum data being used as a reference for a case where air pressure of a tire attached to the wheel is a normal value; and

an air pressure determination means which reads the vibration frequency reference spectrum data from the vibration frequency reference spectrum data storage means on the basis of a current wheel speed or a current vehicle speed, compares a pattern of the thus read vibration frequency reference spectrum data with a pattern of current vibration frequency spectrum data produced by the vibration frequency spectrum data producing means, and determines that the tire is underinflated if a comparison result of these patterns exceeds a predetermined value.

6. A tire pressure monitoring system according to claim 5, further comprising means for producing the current vibration frequency reference spectrum data at the time of driving the vehicle by means of applying a predetermined converting process to the detection values from the wheel vibration detection means, wherein the produced vibration frequency reference spectrum data is stored in the vibration frequency reference spectrum data storage means in a manner associated with vehicle speed.

7. A system for producing wheel vibration frequency spectra comprising

a wheel vibration frequency sensing means,

a vibration frequency data storage means,

data processing means for converting vibration frequency data into vibration frequency spectra,

vibration frequency spectra storage means for storing vibration frequency spectra,

and comparison means for comparing stored vibration frequency spectra with instant vibration frequency spectra.

8. The system for producing wheel vibration frequency spectra of claim 7 wherein the wheel vibration frequency sensing means comprises a wheel speed sensor.

9. The system for producing wheel vibration frequency spectra of claim 7 wherein the vibration frequency data storage means provides storage for a plurality of vibration frequency data sets wherein each of the vibration frequency data sets is associated with a given wheel speed.

10. The system for producing wheel vibration frequency spectra of claim 9 wherein possible wheel speeds are partitioned into plural wheel speed bands, each wheel speed band of the plural wheel speed bands including a range of wheel speeds, and wherein

a vibration frequency data set is provided for each of the plural wheel speed bands, and

a vibration frequency spectra is provided for each of the plural wheel speed bands.

11. The system for producing wheel vibration frequency spectra of claim 10 wherein the comparison means determines the instant wheel speed, and selects the stored vibration frequency spectra from the wheel speed band that includes the instant wheel speed, for use in comparison with the instant vibration frequency spectra.

12. The system for producing wheel vibration frequency spectra of claim 11 wherein the system further comprises signaling means, and wherein when the results of the comparison between the stored vibration frequency spectra and the instant vibration frequency spectra is greater than a predetermined value, the signaling means is activated.

13. A tire pressure monitoring system for monitoring tire pressure within the wheel of a vehicle, the system comprising

a microprocessor, the microprocessor including data input means, data output means, data processing means and data storage means,

the system further comprising a wheel vibration detection means, vehicle speed determination means, and a tire pressure signaling means,

wherein the data processing means comprises means for producing vibration frequency spectra,

wherein data from the wheel vibration detection means detected under normal tire pressure conditions is input to the microprocessor and processed into vibration frequency reference spectra, and

wherein plural vibration frequency reference spectra are stored within the data storage means, such that at least one vibration frequency reference spectrum is stored for each of a plurality of vehicle speed ranges,

wherein data from the wheel vibration detection means under current tire pressure conditions is input to the microprocessor and processed by the data processing means into vibration frequency current spectra, and

wherein the data processing means provides a comparison between the vibration frequency current spectra and the stored vibration frequency reference spectra for a vehicle speed corresponding to the current vehicle speed,

and wherein the tire pressure alarm is activated by the data output means when the results of the comparison exceed a predetermined level.

14. The tire pressure monitoring system of claim 13 wherein both the vibration frequency current spectra and the vibration frequency reference spectra are normalized prior to the comparison.

15. The tire pressure monitoring system of claim 13 wherein the vehicle speed is calculated from data obtained from a sensor sensing wheel vibrations.

16. The tire pressure monitoring system of claim 13 wherein vehicle speed is calculated from data obtained from a sensor sensing wheel rotations.