Abstract: A temperature control device for an oxygen concentration sensor having a solid electrolytic member having oxygen ion-conductivity, a gas diffusion-limiting zone defined by the solid electrolytic member and into which is introduced a gas the concentration of which is to be examined, and a couple of electrodes between which the solid electrolytic member is interposed. Pumping current is supplied to the solid electrolytic member and flows therein between the electrodes to cause an oxygen ion flow in the solid electrolytic member between the electrodes to vary the concentration of oxygen present within the gas diffusion-limiting zone. The pumping current is varied in response to the concentration of oxygen within the gas diffusion-limiting zone, whereby the concentration oxygen in the gas is detected from the pumping current value.

Abstract: An oxygen concentration-sensing device has an oxygen concentration-sensing element which senses the concentration of oxygen contained in a gas, and a heater which heats the sensing element. A control device is electrically connected to the heater for controlling the supply of electricity to the heater so as to bring the temperature of the heater to a desired temperature. A coupler connects between the sensing element and the control device. A compensating resistance is accommodated in the coupler, which has a resistance value corresponding to a resistance value of the heater assumed at the desired temperature. The control device controls the supply of electricity to the heater based upon electrical information obtained from the compensating resistance.

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: An oxygen concentration detecting device includes at least one oxygen concentration detecting element formed by an oxygen-pumping element and a cell element, composed of an oxygen ion-conductive wall, separating a pair of electrodes. The oxygen-pumping element and cell element define a gas diffusion chamber. A current detecting resistance forms a series circuit with the oxygen-pumping element. A voltage applying circuit applies to the series circuit an output voltage corresponding to the difference between a voltage between the electrodes of the cell element and a first reference voltage. An output detecting circuit outputs a voltage signal corresponding to a value of pumping current flowing through the resistance. An operational amplifier has a non-inverting input terminal supplied with a second reference voltage, an inverting input terminal connected to one end of the resistance, and an output terminal connected to the other end of the resistance.

Abstract: A device for detecting and measuring the concentration of a gas in a mixture of gas such as oxygen in the exhaust gas of an internal combustion engine and circuits for using that measurement to control the air-fuel ratio supplied to the engine. The detecting device has two separate gas residence chamber with different diffusion resistance openings for each chamber and separate pairs of electrodes for each chamber whereby the measurement can be separately made in each chamber. The particular chamber selected for measurement may be done on the basis of whether the air-fuel ratio is lean or rich whereby a substantially linear reading results for all ratios or on the basis of the transition-state or steady-state operating condition of the engine to provide either more rapid or more accurate readings.

Abstract: A control system for ignition timing and boost pressure in an internal combustion engine equipped with a turbocharger. The system has a device for detecting knocking in the respective cylinders and the result of the detection by this a device is used as the basis for calculating the ignition timing for each cylinder. When the mean ignition timing calculated from the ignition timings for all cylinders exceeds a prescribed reference value, the boost pressure is reduced. Alternatively, the boost pressure is immediately reduced when the most retarded of the ignition timings exceeds the prescribed value in the direction of retardation, irrespective of whether or not the average value exceeds the prescribed value. As a result, reduction of engine output can be minimized while precluding damage to the engine.

Abstract: An oxygen concentration-sensing device includes an oxygen concentration-sensing element formed by an oxygen-pumping element and a cell element, each composed of an oxygen ion-conductive electrolytic member and a pair of electrodes having the member interposed therebetween. The two elements define a gas diffusion-limiting zone therebetween. A current-to-voltage converter circuit has an input terminal connected to the junction between mutually connected ones of the electrodes. A first amplifier generates an output having a level variable in response to the difference between a potential at a conversion output terminal of the current-to-voltage converter circuit and a potential at the other electrode of the cell element, and applies the output to the other electrode of the oxygen-pumping element. A second amplifier has an input thereof connected to the above junction and generates an output proportional to current flowing in the oxygen-pumping element.

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 method for controlling an oxygen concentration sensor in which the supply of a heater current to a heater element is started when the complete combustion of the engine is detected. The supply of a pump current to an oxygen pump element is started when an internal resistance of the heater element is determined to be in a predetermined range. The supply of the pump current is started when the temperature of the oxygen pump element and the sensor cell element becomes sufficiently high to prevent the pump current from flowing excessively, thereby preventing the generation of blackening phenomenon.

Abstract: An apparatus for controlling ignition timing in an internal combustion engine determines the amount of adjustment of ignition timing for preventing knocking with reference to the engine operating state. The amount of adjustment of the ignition timing carried out upon the detection of knocking is varied depending on the engine speed. Specifically, it is made large in the low speed region where the interval between successive firings is relatively long, thus increasing the speed with which knocking can be prevented and enhancing the protection of the engine from damage in this operating region. Also, rapid acceleration and other transient engine operating states are detected and a transient state adjustment is calculated separately of the adjustment amount for knocking prevention. The transient state adjustment is added to the knocking prevention adjustment and the result is used for retarding the ignition timing, whereby knocking can be effectively prevented during rapid acceleration.

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 and an apparatus for controlling ignition timing in an internal combustion engine. When the ignition timing has been retarded for preventing knocking and the engine operation thereafter moves into a region of operation where knocking control is unnecessary with the retardation of the ignition timing still in effect, the ignition timing is slightly advanced once per predetermined number of firings. Since the ignition timing is gradually restored, engine output hunting is prevented. The advancement of the ignition timing is determined whether or not a prescribed wait period has passed. The period varies depending on an engine speed.

Abstract: A method of and an apparatus for controlling ignition timing in an internal combustion engine, which determines the ignition timing on the basis of the engine speed and load state, discriminates whether or not knocking has occurred on the basis of the output of a knocking detection circuit, retards the so-determined ignition timing by a predetermined amount when knocking occurs, and advances the ignition timing by a predetermined amount after knocking has been avoided. The maximum amount of retardation and advancement carried out upon occurrence of knocking is varied depending on one or more engine operating conditions, enabling the ignition timing to be controlled to near MBT and the engine output to be the maximum possible. The said engine operating condition or conditions include an engine speed in the case of compensation in the direction of ignition retardation and include an engine speed and a load state in the case of compensation in the direction of ignition advance.

Abstract: A method of and an apparatus for controlling boost pressure in a turbocharged internal combustion engine. A turbine disposed in the engine exhaust passage is driven by exhaust gas and in turn drives a compressor disposed in the engine air intake passage, thus boosts the engine combustion chamber by delivering pressurized air thereto. The boost pressure is reduced when the actual ignition timing becomes more retarded than a reference ignition timing. The reference ignition timing is varied in proportion to an engine speed and/or an intake air pressure. Since the decision whether or not to reduce the boost pressure is based on the ignition timing actually being applied to the engine, no risk of damage to the engine arises and unnecessary reduction of engine output can be reliably prevented, enabling the engine to operate with optimum performance.

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: An oxygen concentration sensor having an oxygen ion conductive solid electrolyte member forming a gas diffusion restricted region into which a measuring gas is introduced, includes a pump current source for supplying a pump current across a pair of electrodes sandwiching the solid electrolyte through a current detection element and a heater for heating the solid electrolyte. By an arrangement in which the current detection element is connected to one of the pair of electrodes facing the gas diffusion restricted region, error of measurement due to leakage of a drive current of the heater is prevented.

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.