Nippondenso Co., Ltd.

Toyota Jidosha Kabushiki Kaisha

Denso Corporation

Nippon Soken, Inc.

Advics Co., Ltd.

Mitsubishi Jidosha Engineering Kabushiki Kaisha

Mitsubishi Jidosya Kogyo Kabushiki Kaisya

Kenji Fujiwara

Takeyasu Taguchi

Toshiharu Naito

Takaji Umeno

Hideki Ohashi

Masahiko Kamiya

Takashi Watanabe

Hiroyoshi Kojima

Yoshihiro Nishikawa

Hiroyuki Masuda

Hiroyuki Kawai

Shusaku Fujimoto

Yuuichi Inoue

Hiromi Tokuda

Kotaro Kajiwara

Motoji Suzuki

Motonari Tominaga

Noriyuki Sakai

Mitsuharu Yokoyama

A failure check apparatus for a control apparatus of a vehicle such as ABS. When the failure check apparatus performs initial check for the ABS, it successively activates each of solenoid valves and a motor provided in the ABS, one at a time, for a predetermined time so as to determine whether a failure has occurred in the ABS. At that time, activation of the motor is started when a certain delay time elapses after the end of activation of the last solenoid valve. The delay time is a time which the vibration generated in the control apparatus upon activation of the last solenoid valve converges. Thus, interference between a vibration wave (sound wave) generated upon actuation of the solenoid valves and a vibration wave (sound wave) generated upon actuation of the motor, which differ in nature of vibration, is prevented.

Failure check apparatus for control apparatus of vehicle

When pressure in any one of tires of a vehicle becomes abnormally low, the tire pressure detecting device detects it and gives a warning to a driver. The tire pressure detection is solely performed based on a value calculated by an on-board micro computer from wheel speeds of each wheel sensed by wheel speed sensors. The calculated value to be used for the tire pressure detection must represent correctly the tire pressure. Whenever the calculated value has a possibility to misrepresent the tire pressure, such value is eliminated from the data for judging the tire pressure. When the value is calculated under a situation where any tire is slipping relative to a road surface, it is highly possible that the calculated value misrepresents the tire pressure. The situation where the tire slippage exists is found out by comparing a driving wheel acceleration with a driven wheel acceleration, and the value calculated under such situation is omitted from the data to be used for judging the tire pressure. It is also possible to prohibit calculation of the value when the tire slippage is found out. Thus, the tire pressure is detected with a high reliability.

Tire pressure detecting device which compares driven and driving wheel

An apparatus for estimating an air pressure of a tire of a tired wheel of a motor vehicle, on the basis of a temperature of the tire as well as a motion of the tired wheel, preferably including a temperature-related variable sensor for detecting a temperature-related variable related to the temperature of the tire, and an estimating device for estimating the air pressure of the tire on the basis of the temperature-related variable as well as the motion of the tired wheel.

Apparatus for estimating vehicle tire air pressure from not only tired

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

Growing community of inventors

Kariya, Japan

Kenji Fujiwara