Abstract: A control device for a multicylinder engine comprising a knocking detector for detecting the occurrence of knocking, a crank angle sensor for generating a signal indicative of the crank angle, an engine operating condition control device for governing the engine operating condition, and a control circuit for identifying one of the engine cylinders in which knocking has actually occurred, in dependence on both outputs from the detector and the crank angle sensor. The control circuit operates to cause the engine operating condition control device to control the at least one of the engine cylinders when the output from the detector is lower than a predetermined value, but to control all of the engine cylinders when it is higher than the predetermined value.

Abstract: A closed loop fuel control system for an automobile internal combustion engine, which derives a control signal indicative of the air-fuel mixing ratio and adapted to control the supply of a mixture of gasoline with alcohol to maintain the air-fuel mixing ratio at a stoichiometric value is used to control either the ignition timing or the rate of supply of exhaust gases being recirculated through the EGR system. This is applicable where as an automobile fuel, a mixture of air with blended fuel comprising, for example, gasoline and alcohol is used.

Abstract: An air-fuel ratio control system for an automobile engine of a type having a fuel injection system wherein at least two of parameters including the engine speed, the opening of a throttle valve and the negative pressure developed inside a fuel intake passage are utilized to detect the rate of flow of incoming air to be mixed with an injected mist of fuel to form a combustible mixture. The amount of fuel to be injected into the intake passage depends on the detected rate of flow of the incoming air. A composition sensor for detecting the concentration of an exhaust gas component is also provided for controlling an EGR control valve for controlling the recirculation of a portion of exhaust gases from an exhaust passage into the intake passage.

Abstract: An air-fuel ratio control system for an automobile engine of a type having a fuel injection system wherein at least two of parameters including the engine speed, the opening of a throttle valve and the negative pressure developed inside a fuel intake passage are utilized to detect the rate of flow of incoming air to be mixed with an injected mist of fuel to form a combustible mixture. The fuel injection system includes a fuel adjusting device so designed as to provide, when the engine operates within a particular operating region, the combustible mixture of an air-fuel mixing ratio lower than that to be supplied to the engine when the latter operates within the other operating region than the particular operating region.

Abstract: An air-fuel ratio control system for an automobile engine including a source of combustible air-fuel mixture on an intake passage and an exhaust gas purifying unit on an exhaust passage includes a composition sensor for generating an output signal indicative of the concentration of a particular component of exhaust gases flowing through the exhaust passage, a control unit for generating a control signal in dependence on the output signal, a pressure sensor for generating a pressure signal indicative of the pressure inside the intake passage, and an actuator operable in response to the control signal to adjust the air-fuel mixing ratio to a predetermined optimum value. The control unit is so designed to fix the duty ratio of the control signal at a mean value of the highest and lowest values of the duty ratio of the previous control signal if it has attained a generally identical value two or more times consecutively.

Abstract: An air-fuel ratio control system for an automobile engine of a type having a fuel injection system wherein at least two of parameters including the engine speed, the opening of a throttle valve and the negative pressure developed inside a fuel intake passage are utilized to detect the rate of flow of incoming air to be mixed with an injected mist of fuel to form a combustible mixture. The amount of fuel to be injected into the intake passage depends on the detected rate of flow of the incoming air. A composition sensor for detecting the concentration of an exhaust gas component is also provided for controlling an EGR control valve for controlling the recirculation of a portion of exhaust gases from an exhaust passage into the intake passage.

Abstract: An internal combustion engine has an exhaust gas recirculation system including a recirculation valve for controlling the amount of exhaust gas returned to the intake system. The position or opening of the valve is controlled to a desired position in accordance with a memory in a memory device storing desired valve positions under various combinations of the engine load and the engine speed. A device is provided for increasing the opening of the recirculation valve when the effective area of the recirculation passage is decreased due to carbon deposits.

Abstract: An automobile air-fuel control system is incorporated with an altitude compensator in order to minimize an excessive enrichment of an air-fuel mixture which would occur when the engine is operated at a high altitude under a high load operating condition. This altitude compensator is constituted by a delay circuitry operable to delay the timing at which the supply of bleed air for leaning the mixture is interrupted when the engine is operated at a high altitude under the high loaded condition.