Hitachi, Ltd.

Unisia Jecs Corporation

Atsugi Motor Parts Company, Limited

Hitachi Automotive Systems, Ltd.

Tamotsu Yamaura

Fumiyuki Yamaoka

Yutaka Makino

Kenichi Hamada

Mitsuo Sasaki

Sunao Hano

Nobuyuki Ohtsu

Gen Inoue

Atsushi Matsuoka

A diagnosing system for diagnosing a control device of a vehicle-mounted equipment is provided, which has a chip of integrated circuit that stores a control program data for controlling the vehicle-mounted equipment, a control program data storage zone arranged in the chip and storing the control program data for controlling the vehicle-mounted equipment, a diagnosing data storage zone arranged in the chip and storing a diagnosing data that is provided by modifying the control program data and a data abnormality diagnosing section that detects an abnormality of the control program data by comparing the control program data with the diagnosing data.

Diagnosing system for diagnosing control device of vehicle-mounted equipment

A failure detection apparatus for a resolver outputting a sine signal indicative of sin &#x3b8; and a cosine signal indicative of cos &#x3b8; according to a rotational angle &#x3b8; of a rotator, includes an inspection value calculating section configured to calculate an inspection value based on at least one of the sine signal and the cosine signal; a failure detecting section configured to judge whether the resolver is in a failure state or not on the basis of the inspection value; a counting section configured to gradually increase a count value with a lapse of time when the failure detecting section is determining that the resolver is in the failure state, and configured to gradually decrease the count value with a lapse of time when the failure detecting section is determining that the resolver is not in the failure state; and a failure deciding section configured to finally decide that the resolver has caused the failure on the basis of the count value.

Failure detection apparatus for resolver

A power steering apparatus includes an electric motor, a temperature sensor, and a control unit. The electric motor produces an assist steering effort in a steering system. The temperature sensor measures a temperature of a first portion subject to thermal influence of operation of the electric motor. The control unit determines an estimated temperature of a second portion in accordance with a value of a motor current, the second portion being subject to thermal influence of operation of the electric motor. The control unit determines a first upper limit value in accordance with the measured temperature; determines a second upper limit value in accordance with the estimated temperature; limit the motor current to a smaller one of the first and second upper limit values, when determining that the temperature sensor is normal; limit the motor current to the second upper limit value, when determining that the temperature sensor is abnormal.

Power steering apparatus

An automotive brake control system with an anti-brake skid (ABS) unit which controls a wheel-brake cylinder pressure to each individual wheel cylinder of the road wheels to prevent a wheel lock-up condition during braking, and an ABS control unit being configured to be connected electrically to at least wheel speed sensors and the ABS unit to execute skid control having at least a reduce-pressure operating mode and a pressure build-up operating mode, when the wheel speed sensor signals indicate that at least one of the road wheels is locking up. The ABS control unit includes a road-surface-condition change determination section which determines, based on both a time length of brake-fluid-pressure control continuously executed during the skid control and a recovery acceleration of the wheel speed of the road wheel subjected to the skid control, whether there is a road-surface &mgr; change from low-&mgr; road to high-&mgr; road.

Automotive brake control system with anti-skid braking device

A road surface condition determination system for an automotive vehicle comprises wheel-speed sensors, and a control unit being configured to be electrically connected to the wheel-speed sensors for data-processing a wheel-speed data signal. The control unit calculates a wheel-speed fluctuation of each of the road wheels on the basis of a previous value of the wheel-speed data signal and a current value of the wheel-speed data signal, and calculates an absolute value of the wheel-speed fluctuation of each of the road wheels. A integration circuit is provided to produce a first integrated value of the absolute values of the wheel-speed fluctuations of the road wheels. A smoothing circuit is provided to make a smoothing operation to the integrated value to produce a smoothed value. A road-surface condition determining section is also provided to determine a road surface condition on the basis of the smoothed value. In an automotive vehicle with an ABS system, a skid control section uses the result of discrimination between good and bad roads, executed by the road-surface condition determining section, so as to vary a pressure-reduction threshold depending on the road surface condition detected.

Road surface condition determination system for automotive vehicles and anti-skid braking system having the same

A shock absorber comprises a cylinder assembly defining a working chamber filled with a hydraulic working fluid and disposed therein a piston, and a fluid reservoir chamber filled with the hydraulic working fluid and a pneumatic working fluid, a communication path for connecting the working chamber and the fluid reservoir chamber for fluid communication therebetween, and a check and flow restriction assembly disposed within the communication path for selectively establishing and blocking fluid communication between the working chamber and the fluid reservoir chamber, the check and seal assembly includes a fluid check valve and a fluid flow restriction arranged in series, the flow restriction permitting pneumatic and hydraulic fluid flow directed to the fluid reservoir chamber during piston bounding stroke and providing flow restriction for the hydraulic fluid flow, and the check valve blocking fluid communication between the fluid reservoir chamber and the working chamber during piston rebounding stroke and permitting hydraulic fluid flow during the piston bounding stroke.

Shock absorber

A shock absorber is provided a piston stroke dependent variable shock absorbing characteristics by means of a first and second flow restriction valves associated with a piston. The first and second flow restriction valves are arranged in a fluid path for communicating first and second working chambers defined within a shock absorber cylindrical housing in series. The first flow restriction valve is associated with an orifice forming a part of the fluid path and has variable flow restriction rate in response to a pressure difference between the first and second chambers greater. The second flow restriction means is disposed in tandem fashion with the first flow restriction valve for providing a predetermined constant flow restriction rate in response to the pressure difference smaller than a predetermined criterion and providing a variable flow restriction as a function of the piston stroke speed in response to the pressure difference greater than the predetermined criterion.

Growing community of inventors

Atsugi, Japan

Tamotsu Yamaura