Nippondenso Co., Ltd.

Toyota Jidosha Kogyo Kabushiki Kaisha

Hiromi Tokuda

Hidetaka Nohira

Masayoshi Takeda

Hiroshi Ishikawa

Takeyasu Taguchi

Toshiharu Naito

Kenji Fujiwara

Shusaku Fujimoto

Yuuichi Inoue

Tadaki Nakayama

Kouji Watanabe

Shigefumi Nakamura

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

A shock absorber is connected between a vehicle body and a vehicle wheel. The shock absorber provides a variable damping force. A control apparatus for the shock absorber includes an actuator for adjusting the damping force provided by the shock absorber. A vibration detecting device serves to detect a relative vibration between a spring upper member and a spring lower member. A damping-factor estimating device serves to estimate a damping factor of the shock absorber. A speed estimating device serves to estimate an absolute speed of the spring upper member on the basis of the relative vibration detected by the vibration detecting device and the damping force estimated by the damping-force estimating device. A signal setting device serves to set a drive signal of the actuator on the basis of the absolute spring upper member speed estimated by the speed estimating device.

Shock absorber control apparatus

In an exhaust gas recirculation system of the type including a control valve inserted in an exhaust gas recirculation passageway for controlling the flow rate of the exhaust gases to be recirculated, a constant pressure chamber defined in the recirculation passageway upstream of the control valve, and a modulator valve with a diaphragm chamber in communication with the constant pressure chamber for controlling, in response to the pressure variation in the diaphragm chamber, the negative pressure which is transmitted to the control valve for operating the same, an orifice is interposed between the constant pressure chamber and the diaphragm chamber and is so contoured that the resistance to the flow from the diaphragm chamber to the constant pressure chamber is greater than the resistance to the flow from the constant pressure chamber to the diaphragm chamber.

Exhaust gas recirculation system

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Nagoya, Japan

Hiromi Tokuda