Abstract: An engine control system for suppressing vibration of a car body, primarily at acceleration thereof, by varying engine output torque. The system for suppression of the car body vibration takes into consideration car vibration detection delay time created by the intermittent detection of vibration data. The system includes a detector for intermittently detecting data relating to car body vibration, a period setting device for setting a period of car body vibration, a delay time setting device for setting a delay time corresponding to a detection delay time due to the intermittent detection of the vibration data detector, and a torque controller for controlling engine output torque by advancing a phase of engine output torque control timing by the delay time corresponding to the detection delay time, which is set by the delay time setting device, in each period of car body vibration set by the period setting device.

Abstract: Oscillation of the engine is detected by an oscillation sensor which outputs a signal representing the oscillation of the engine. The maximum value of the output of the oscillation sensor during combustion period in each cycle is detected. The maximum values obtained in a predetermined number of cycles are stored in a memory and knock occurrence is determined on the basis of the predetermined number of maximum values output from the memory.

Abstract: An ignition timing correcting circuit which retards ignition timing when knock occurs and advances ignition timing when knock does not occur. An optimal ignition timing on which the ignition timing is to be converged is set to a latest ignition timing to which the ignition time can be retarded without raising the exhaust gas temperature higher than a predetermined value at the actual air-fuel ratio at that time. The actual ignition timing corrected by the ignition timing correcting circuit is compared with the optimal ignition timing. An air-fuel ratio control circuit corrects the air-fuel ratio toward the lean side when the actual ignition timing is on the advance side of the optimal ignition timing and toward the rich side when the former is on the retard side of the latter.

Abstract: An air-fuel ratio control system for an automobile engine including an intake passage having a throttle valve, and a fuel supply unit, which comprises an air detector for generating an air signal indicative of the quantity of air sucked to the engine through the intake passage, a throttle detector for generating a throttle signal indicative of the opening of the throttle valve, and a control unit operable in response to the signals from the air and throttle detectors for determining the air-fuel ratio of a combustible air-fuel mixture to be supplied to the engine in dependence on the amount of air sucked when a load on the engine is small, but on the opening of the throttle valve when the load on the engine is great.

Abstract: A multiple cylinder engine including a first group of cylinders having a first intake passage which is provided with an air-fuel mixture of a predetermined ratio in accordance with the signal from an exhaust gas sensor provided in the exhaust passage from the first group of cylinders. The engine further includes a second group of cylinders having a second intake passage which is provided with a mixture having an air-fuel ratio which is of a predetermined relationship with respect to the air-fuel ratio of the mixture into the first group of cylinders, the predetermined relationship being determined in accordance the engine operating condition. An exhaust gas recirculation system is provided for controlling the recirculation gas flow to the second intake passage with respect to the recirculation gas flow to the first intake passage in accordance with the engine operating condition.