Denso Corporation

Other

Toyota Jidosha Kabushiki Kaisha

Nippon Soken, Inc.

Densco Corporation

Yuichi Inoue

Takeyasu Taguchi

Yukio Mori

Hideki Ohashi

Toshiharu Naito

Takaji Umeno

Kazuhiro Kamiya

Masahiro Yonetani

Masaaki Tabata

Mamoru Sawada

Motonori Tominaga

Nobuyoshi Onogi

Hideki Kabune

A tire air pressure detection device includes an ideal driving status calculating portion () and a rotational status value compensating portion (). The ideal driving status calculating portion calculates an ideal status value (&#x3b2;id) corresponding to a slip value under an ideal driving status without tire slippage. The rational status value compensating portion calculates and ideal rotational status value under the ideal driving status without tire slip based on the regression line calculated by a regression line calculating portion () and the ideal slip status value calculated by the ideal driving status calculating portion.

Tire air pressure detection device for detecting air pressure based on vehicle speed signal

The invention provides an apparatus and a method of estimating tire air pressure with high accuracy from vehicle operation at low at high speeds regardless of various elements to be mounted to the vehicle. Estimation of tire air pressure based on a resonance frequency extracted based on a wheel speed signal outputted from a wheel speed sensor corresponding to the respective tire and estimation of tire air pressure based on a dynamic load radius derived based on the wheel speed signal, are used to selectively switch in accordance with a magnitude of a variance value of the resonance frequency at a plurality of time points.

Method and apparatus for estimating tire air pressure

Lowpass and highpass filters, having cutoff frequencies different from each other, are used to perform first to fourth filter processing. Then, product-sums of outputs of respective filter processing are obtained. Then, frequencies corresponding to the resonance frequency are obtained based on the result of respective product-sum calculations. The thus obtained frequencies are different from each other in the degree of influence of noise components. Then, among the obtained frequencies, an optimum frequency having less influence of noise components is selected. Then, the selected frequency is smoothed to obtain a resonance frequency for a pneumatic tire pressure estimation.

Pneumatic tire pressure estimating apparatus

Tire air pressure determining apparatus and method of determining tire air pressure

In a tire air pressure warning device, an outside impact such as hydraulic brake pressure is intentionally applied in a pulsating way to a tire when the vehicle substantially stops so as to exert vibration (rotation variation) of the tire axle. Through data processes in analyzing signals of wheel speed sensors that reflect the rotation variation of the tire axle, tire air pressure is estimated for informing to a driver abnormal tire air pressure.

Tire air pressure warning device

A signal processor comprises wheel speed-detecting means for detecting a wheel speed signal including vibrational components of a tire, extraction means for extracting a resonant frequency of the vibrational components of the tire or a tire spring constant based on the wheel speed signals, air pressure-estimating means for estimating a tire air pressure based on the resonant frequency or the tire spring constant, and determining means for determining whether the estimated tire air pressure is abnormal or not by comparing with a determination value. Further, correcting means corrects at least one of the determination value, the estimated tire air pressure, the resonant frequency and the tire spring constant in response to a tire temperature. A temperature-sensing device is mounted inside the signal processor to detect a temperature associated with the tire temperature.

Apparatus for estimating tire air pressure

To achieve both accuracy in correcting sensing error caused by nonstandard factors of a pulse signal generated by rotation of a rotor to be measured and reduction in cost of an apparatus for doing the same, each passage of rotor sensors which rotate integrally with vehicle tires are sensed to produce pulse signals. The pulse signal periods are sequentially integrated every pulse signal train consisting of multiple pulse signals. When all of the pulse signal periods of the pulse signal train are integrated, the integrated value is stored in memory. The memory always stores the integrated values of the newest one rotation of the rotor to be measured. The pulse signal periods are averaged from the sum of the integrated values. With such a construction, the average of the pulse signal periods can be obtained as a learning reference value in the correction without storing all of the pulse signal periods of one rotation, thereby realizing both correction accuracy and cost reduction.

Tire abnormality sensor

Growing community of inventors

Tajimi, Japan

Yuichi Inoue