Abstract: The method of the present invention improves the damping property of the yaw motion of the vehicle by feeding back a detected yaw rate value in a dynamic sense for compensating the front wheel steer angle so as to increase the damping coefficient of the yaw motion of the vehicle. By controlling the front wheel steer angle by accounting for not only the proportional term of the steering wheel input angle but also the derivative term which is proportional to the steering wheel input angular speed, in the feed-forward control of the front wheel steer angle in relation with the steering operation by the driver, and by appropriately varying the control parameters of the yaw rate feed-back and the steering wheel input feed-forward, the yaw response of the vehicle can be made proportional to the steering wheel input, and the response delay in the yaw rate against the steering wheel input can be reduced to substantially zero.

Abstract: A method for feedback controlling an air/fuel ratio of mixture supplied to an internal combustion engine to a target air/fuel ratio, which uses an output signal of an oxygen concentration sensor. The sensor's output signal is proportional to the oxygen concentration in the exhaust gas of the engine. When the target air/fuel ratio is set at a stoichiometric air/fuel ratio, the air/fuel ratio of the mixture is varied by a small amount around the stoichiometric value if the air/fuel ratio of mixture supplied to the engine is detected to be in a predetermined air/fuel ratio range which includes the stoichiometric air/fuel ratio. The determination of the air/fuel ratio is calculated from the output signal of the oxygen concentration sensor.

Abstract: A method for controlling an oxygen concentration sensor for controlling an internal combustion engine, having a sensor body including a wall of oxygen ion conductive solid electrolyte member, and a heater element for heating the wall of oxygen ion conductive solid electrolyte member. During a time period after the ignition switch of the internal combustion engine is turned on, current value of the heater current to the heater element is reduced to a value which is smaller than the current value of the heater current to be supplied after the lapse of the time period.

Abstract: A system of abnormality detection for an oxygen concentration sensor employed to sense the oxygen concentration in engine exhaust gas, for obtaining data to control the air/fuel ratio of a fuel mixture supplied to the engine, the oxygen concentration sensor including a sensor cell element and an oxygen pump element. The system serves to detect an abnormality such as an open-circuit or a short-circuit in electrode connecting leads of the oxygen pump element, on the basis of a level of the sensed pump current together with an air/fuel ratio compensation value which is derived from a sensed oxygen concentration level.

Abstract: A method of engine air/fuel ratio control using an oxygen concentration sensor producing a concentration-proportional output, in which a compensation value is computed for compensating a basic value such as a basic fuel injection time interval, and in which a deviation of an air/fuel ratio detected using the oxygen concentration sensor from a target air/fuel ratio is measured the compensation value is computed and updated only under the condition that the deviation is below a predetermined value, with the compensation value being determined in accordance with the amount of deviation.

Abstract: Abnormalities are detected in an oxygen concentration sensor employed to sense the oxygen concentration in engine exhaust gas for obtaining data to control the air/fuel ratio of a fuel mixture supplied to the engine, in which the oxygen concentration sensor includes a sensor cell element and an oxygen pump element. The method functions to detect an abnormality of the oxygen concentration sensor on the basis of the value of sensor voltage which is developed by the sensor cell element and at least one of a set of parameters consisting of an engine operating condition, the value of pump current which flows between the electrodes of the oxygen pump element, and an air/fuel ratio compensation value which is derived from a sensed oxygen concentration level.

Abstract: A method of air/fuel ratio control for a multicylinder internal combustion engine, utilziing an oxygen concentration sensor which produces an output varying in proportion to oxygen concentration, in which compensation values are computed and stored for use in compensating errors of a basic value which controls the air/fuel ratio. While the engine is operating in a condition condition in which the deviation of a detected air/fuel ratio from a target air/fuel ratio is below a predetermined level, respective compensation values are computed and updated for the individual cylinders of the engine, with these compensation values being computed in accordance with variations in the magnitude of the detected air/fuel ratio.

Abstract: Compensation of an output from an oxygen concentration sensor of an air/fuel ratio control apparatus for an internal combustion engine is executed during engine warm-up, to correct for an erroneous component in the oxygen concentration sensor output data caused by incomplete combustion during warm-up. The degree of compensation applied is determined by the engine operating temperature, as represented by the cooling water temperature. Excessive richness of the air/fuel ratio of the mixture supplied to the engine during warm-up is thereby eliminated.

Abstract: A method for controlling an air/fuel ratio of an internal combustion engine. The fuel supply is performed normally by a feedback control operation for controlling the air/fuel ratio of the mixture toward a target air/fuel ratio in accordance with an oxygen concentration in an exhaust gas of the engine. A fuel cut operation under a predetermined condition includes a step for detecting a transition from the fuel cut operation to resume the fuel supply, and a step for shifting, for a time period after a detection of the transition, the target air/fuel ratio of the feedback control to a lean side with respect to a target air/fuel ratio value to be used after the elapse of the time period.

Abstract: An oxygen concentration detection apparatus includes a detection unit having a pair of oxygen-ion conductive solid electrolyte walls forming first and second gas retaining chambers on which first and second sets of electrodes, which are designed to operate alternatively, are provided. First and second current supply circuits are provided for alternatively supplying first and second pump currents respectively on the first and second sets of electrodes. Between the current supply circuits and the sets of electrodes respectively, a first variable resistor and a second variable resistor are provided so that adjustment operations are enabled separately for obtaining an accurate overall output signal characteristic of the oxygen concentration detection apparatus.

Abstract: A method of engine air/fuel ratio control whereby a compensation value is computed for compensating an error of a basic fuel injection time interval. The computation is periodically performed as an operating sequence including steps of computing a current first compensation value, utilizing a preceding first compensation value (obtained and memorized during a previous execution of the sequence, under the same engine operating conditions as those of the current first computation value), obtaining a second compensation value based on the deviation between a detected air/fuel ratio and a target air/fuel ratio, and compensating the basic value by the first and second compensation values to obtain an output value, used to control fuel supply to the engine. In addition, while engine acceleration or deceleration is occurring, the basic value is corrected by a transition compensation value, computed in accordance with the degree of acceleration or deceleration.

Abstract: A system of abnormality detection for an oxygen concentration sensor employed to sense the oxygen concentration in engine exhaust gas for obtaining data to control the air/fuel ratio of a fuel mixture supplied to the engine. In which, the oxygen concentration sensor includes a sensor cell element, an oxygen pump element each formed of a pair of electrodes which sandwich a solid electrolytic member, and a heater element for heating the solid electrolytic member. The system functions to detect an abnormality of the heater element on the basis of the value of a voltage developed between the electrodes of the sensor cell element and an air/fuel ratio compensation value that is derived by sensing the exhaust gas oxygen concentration.

Abstract: A system of abnormality detection for an oxygen concentration sensor employed to sense the oxygen concentration in engine exhaust gas, and to obtain data to control the air/fuel ratio of a fuel mixture supplied to the engine. The oxygen concentration sensor including a sensor cell element and an oxygen pump element. The system serves to detect an abnormality such as an open-circuit or a short-circuit in electrode connecting leads of the sensor cell element on the basis of a value of voltage developed between the electrodes of the sensor cell element and of a value of current which flows between the electrodes of the oxygen pump element.

Abstract: An air/fuel ratio control system for an internal combustion engine includes an oxygen concentration sensor for sensing the oxygen concentration in the exhaust gas of the engine, and a correction value setting device which determines a correction value corresponding to an output signal of the oxygen concentration sensor obtained when the fuel cut operation of the engine has continued for more than a predetermined time period. The output signal of the oxygen concentration sensor is corrected by the correction value during the engine operation other than the fuel cut operation.

Abstract: A method for controlling an oxygen concentration detection apparatus mounted on an engine, including an oxygen concentration sensing element and a heater element for heating the oxygen concentration sensing unit, includes an operation for detecting an engine temperature of a time immediately before the start of the supply of a drive current to the heater element, and an operation for controlling the magnitude of the drive current for a time period which is determined correspondingly to the engine temperature, to be lower than a level of the drive current to be supplied to the heater element after the elapse of the time period determined according to the engine temperature.

Abstract: A method for controlling an oxygen concentration sensor mounted on an engine, including oxygen ion conductive solid electrolyte members operative as an oxygen pump element and a sensor cell element respectively, a source of pump current to be supplied to the oxygen pump element, and a heater element for heating the oxygen pump element and the sensor cell element. The method includes an operation for detecting an engine temperature of a time immediately before the start of the supply of a drive current of the heater element, and a control operation for starting the supply of the pump current after an elapse of a time period determined in response to the engine temperature from the start of the supply of the drive current of the heater element.