Nippondenso Co., Ltd.

Toyota Jidosha Kabushiki Kaisha

Denso Corporation

Nippon Soken, Inc.

Other

Kabushiki Kaisha Toyota Chuo Kenkyusho

Densco Corporation

Toyota Jidosha Kabushiki Kaisha & Kabushiki Kaisha Toyota Chuo Kenkyusho

Toshiharu Naito

Takeyasu Taguchi

Hideki Ohashi

Nobuyoshi Onogi

Yukio Mori

Takaji Umeno

Katsuhiro Asano

Yuichi Inoue

Kenji Fujiwara

Masaaki Tabata

Motonori Tominaga

Kazuhiro Kamiya

Hiroyoshi Kojima

Hiroyuki Kawai

Masahiko Kamiya

Yuuichi Inoue

Mamoru Sawada

Yoshiyuki Hattori

Yoshihisa Nomura

Eiichi Ono

Ikuo Hayashi

Hideki Kabune

Yoshihiro Nishikawa

Shusaku Fujimoto

Masahiro Yonetani

Hidenobu Kazita

Hiromi Tokuda

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

A tire burst predicting device which can predict occurrence of bursting of a tire and gives an alarm properly is provided. A break point frequency is estimated on the basis of time series data of wheel speed detected at a wheel speed sensor from frequency response of a first order model to which a transmission characteristic from a road surface disturbance to a wheel speed is approximated. A braking force gradient corresponding to the estimated break point frequency is estimated, on the basis of a map, which is prestored, representing a relationship between break point frequencies and braking force gradients. Extra high frequency components are eliminated from the estimated braking force gradient by a low pass filter to reduce estimation dispersion. Differentiators detect changing speed of the braking force gradient. An alarm is given when there is a possibility of bursting of tire when the detected changing speed reaches or exceeds a predetermined threshold value.

Tire burst prediction device

A tire air pressure detection device of the present invention includes a warning anticipation timing calculating portion for anticipating a warning timing at which tire air pressure decrease detecting portion will detect the tire air pressure decrease based on rotational status value compensated for by a rotational status value compensating portion. A tire air pressure decrease detecting portion detects a decrease in tire air pressure when a clocked determination time reaches the warning anticipation timing anticipated by the warning anticipation timing calculating portion.

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

In a tire air pressure estimating apparatus, wheel speeds of respective wheels are successively calculated when a vehicle is running. At least one of a tire resonance frequency and a tire spring constant is extracted from vibration frequency components included in a wheel speed signal with respect to each of tires. Tire air pressures of drive wheels are estimated based on the extracted tire resonance frequencies or the tire spring constants. Rotational state values (e.g. wheel speed values) of driven wheel tires are calculated based on the detected wheel speeds. Tire air pressures of driven wheels are estimated based on a deviation of the rotational state values of the driven wheel tires.

Tire air pressure estimating apparatus

A wheel information estimating apparatus, which includes: a detecting device for detecting a wheel motion state relating to a movement of a tired wheel of a motor vehicle; an estimating device for estimating wheel information relating to the tired wheel, on the basis of the wheel motion state detected by the detecting device; and a modifying device for modifying an element relating to estimation of the wheel information, so as to improve an accuracy of estimating the wheel information. The element to be modified is selected from a movement of a center of rotation of the tired wheel as viewed in a plane in which the wheel is rotated, a signal applied from the detecting device to the estimating device, and an internal parameter used by the estimating means for estimating the wheel information.

Wheel information estimating apparatus

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

In a tire air pressure estimation based upon vibration components extracted rom a vehicle wheel speed signal, when the vehicle is a driven vehicle wheel, the precision of estimation is improved by canceling the components of vibration due to the resonance of the drive system from the vibration components based upon which the estimation calculation is made. The vibration components due to the resonance of the drive system can be canceled by canceling those vibration components extracted from the vehicle wheel speed signal which are the same in the phase between left and right driven vehicle wheels. When the tire air pressure of one of a pair of left and right driven vehicle wheels is lower than that of the other, the lower tire air pressure is more correctly estimated. Therefore, the higher tire air pressure may be estimated according to the lower tire air pressure against the drive system resonance.

Device for estimating air pressure of tire from vibration components of

Pickup coils which generate vehicle wheel speed signals which include vibration frequency components of tires during vehicle cruising are provided. An electronic control unit extracts resonance frequencies of tires from the vehicle wheel speed signals and estimates tire pneumatic pressure based on the extracted resonance frequencies. When an estimated vehicle wheel pneumatic pressure falls below a predetermined critical pneumatic pressure, pneumatic pressure decline warnings are generated and displayed by a display unit. An update switch is provided and when this update switch is turned on when replacing tires, the electronic control unit adjusts and sets the value of the critical pneumatic pressure described above based on the resonance frequency extracted during this time.

Tire pneumatic pressure detector

An absolute vehicle speed determining system is provided. This system includes generally a first sensor for detecting an unsprung vibration frequency component acting on a front wheel and a second sensor for detecting an unsprung vibration frequency component acting on a rear wheel. A phase difference between the unsprung vibration frequency components is found to project an absolute speed of a vehicle based on the phase difference and a wheel base of the vehicle. In addition, a tire condition monitoring system is provided which is designed to monitor properties of the tire, for example, the inflation pressure, the type of tire, or the amount of tire wear using the absolute speed of the vehicle projected.

System for projecting vehicle speed and tire condition monitoring system

It is an object of the present invention to detect a tire air pressure indirectly with high detection precision. A tire air pressure detecting device includes a speed sensor for outputting a signal corresponding to a rotational speed of a tire, and an electronic control unit which inputs the signal from the speed sensor and performs predetermined arithmetic operations on that signal. The electronic control unit calculates a wheel speed based on the output signal of the speed sensor, performs a frequency analysis for the calculated vehicle speed, and derives a resonance frequency corresponding to the unsprung mass in the vertical and longitudinal directions. The tire air pressure is then detected based on this resonance frequency.

Tire air pressure detecting device

First and second outlet ports are connected to an inlet port. A first valve member selectively blocks and unblocks the first outlet port. A second valve member selectively blocks and unblocks the second outlet port. A first device urges the first valve member. A second device urges the second valve member. A movable member disposed between the first and second valve members allows a force of the first urging device to travel to the second valve member. The movable member can be driven by a solenoid winding. When the solenoid winding is deenergized, the first valve member is moved to its open position by the first urging device and the second valve member is moved against a force of the second urging device to its open position by the first urging device. When the solenoid winding is energized, the first valve member is moved against the force of the first urging device to its closed position by the movable member and the second valve member is moved to its closed position by the second urging device.

Growing community of inventors

Okazaki, Japan

Toshiharu Naito