Nissan Motor Company Limited

Satoru Ishihara

Kenji Kawagoe

Masatsugu Yokote

Hideo Ito

Kazunobu Kawabata

An electronically controlled power steering system comprises a vehicle speed sensor, a steering wheel angle sensor, a power steering gear including a control valve, a bypass valve for regulating a flow rate of hydraulic fluid supplied to the control valve of the power steering gear in response to a control signal generated by a controller. The controller is operative responsive to sensor output signals of the sensors for generating the control signal. With the controller, the control signal is varied in response to the vehicle speed and the steering wheel angle when the steering wheel angle is less than a predetermined value, but this varying tendency of the control signal in response to the steering wheel angle is restrained when the steering wheel angle is not less than the predetermined value.

Electronically controlled power steering system

A suspension control system employs a road sensor monitoring road roughness or smoothness and producing a road condition indicative signal. The control system also employs other sensor or sensors for monitoring at least one preselected suspension control parameter, such as vehicle speed, steering angular variation and so forth, other than road roughness. The suspension switches between relatively hard and relatively soft characteristics based on the preselected suspension control prameters. In order to make suspension control more precisely suited to the vehicle driving conditions, the control characateristics of the suspension system are adjusted depending upon the road condition. With this arrangement, even when the suspension is controlled so as to suppress vehicular roll based on the steering angular displacement and when rough road conditions cause steering angular displacement due to kick-back from the road input through the steering mechanism, the erroneous judgement that steering adjustments are about to cause vehicular roll can be avoided. In case of acceleration responsive suspension control, rough road conditions tend to cause a driver to unconsciously operate the accelerator pedal so as to increase and decrease throttle valve angular position relative to the fully closed position. According to the present invention, by adjusting the control characteristics, erroneous detection that the vehicle is accelerating, which would normally cause winding-up, can be successfully avoided.

Growing community of inventors

Yokosuka, Japan

Satoru Ishihara