Abstract: An air-fuel ratio control system for an internal combustion engine includes an air-fuel ratio sensor for detecting the air-fuel ratio of exhaust gases from the engine. An ECU estimates the air-fuel ratio of a mixture supplied to each of the cylinders cylinder by cylinder in response to an output from the air-fuel ratio sensor, by using an observer based on a model representative of the behavior of the exhaust system. Cylinder-by-cylinder air-fuel ratio control amounts corresponding respectively to the cylinders are calculated for carrying out feedback control of the air-fuel ratio of the mixture such that each of the estimated air-fuel ratio is converged to a desired value.

Abstract: A control device for a cylinder injection internal-combustion engine detects the deterioration of the combustion efficiency of the engine. The control device is equipped with: a fuel injection valve for directly injecting fuel to each cylinder in the internal-combustion engine; an ignition coil unit for driving a spark plug in each cylinder; an electronic control unit for driving each fuel injection valve and ignition coil unit according to the operational state of the internal-combustion engine; combustion state determining means for determining the combustion state of the internal-combustion engine; and combustion efficiency recovering means for recovering the combustion efficiency of the internal-combustion engine.

Abstract: A method is provided for enriching a fuel to air ratio in an engine during acceleration based on a known fuel multiplier. Initially, the method retrieves the fuel multiplier from a dynamic crankshaft fuel control (DCFC) system. This system uses the fuel multiplier to reduce the amount of fuel delivered to the engine. When acceleration is desired, the method increases the overall acceleration enrichment values as a function of the DCFC fuel multiplier. Thus, when the vehicle is launched via a throttle tip-in while the DCFC system is active, the acceleration enrichment values are increased thereby improving drivability by having combustion taking place in a richer environment.

Abstract: An air-fuel ratio control system for an internal combustion engine includes an ECU which cuts off fuel supply to the engine at deceleration thereof, measures a fuel cut-off period over which the fuel cut-off means cuts off fuel supply to the engine, and enriches the air-fuel ratio of a mixture supplied to the engine to a degree dependent upon the measured fuel cut-off period, at the restart of fuel supply to the engine immediately after termination of cutting-off of fuel supply to the engine.

Abstract: Undershoot of rotation speed is prevented by increasing an intake air amount of an engine when it decelerates. Precise control corresponding to differences of a deceleration state is realized by setting an increase amount of intake air to a different value according to the engine rotation speed and deceleration. Preferably, increasing of intake air amount starts when the engine rotation speed reaches a first predetermined value. It is terminated when the engine rotation speed reaches a second predetermined value smaller than the first predetermined value or when a predetermined time has elapsed, whichever is the sooner.

Abstract: An air-fuel ratio controller for an internal combustion engine, which controller is capable of: properly correcting an air-fuel ratio after a start-up explosion; preventing inconveniences such as occurrence of an engine stall, a decrease in an engine rotational speed, and a discharge of exhaust gases containing harmful components; and, allocating an idle time-learning value with reference to a rotational engine speed that is obtained at the time of engine start-up, thereby enhancing convenience of use.

Abstract: An adjustable interlocking ignition rotor device 10 includes a first member 12 having a plurality of orifices 34 radially positioned around the axis of the first member 12, a second member 14 having a plurality of orifices 56 radially positioned around the axis of the second member 14, and an index screw 16 to secure the first member 12 to the second member 14. The first and second members 12 and 14 are secured to a base portion of a distributor assembly or one end of a crankshaft to adjust the timing of an internal combustion engine. The engine timing is easily adjusted to an advanced or retarded position in relation to a zero degree setting by counting from a zero degree orifice 78 and 80 in both the first and second members 12 and 14 in a corresponding advanced or retarded direction, a quantity of orifices corresponding in number to a predetermined degree of engine timing.

Abstract: Cyclic variation in combustion of a lean burning engine is reduced by detecting an engine combustion event output such as torsional acceleration in a cylinder (i) at a combustion event (k), using the detected acceleration to predict a target acceleration for the cylinder at the next combustion event (k+1), modifying the target output by a correction term that is inversely proportional to the average phase of the combustion event output of cylinder (i) and calculating a control output such as fuel pulse width or spark timing necessary to achieve the target acceleration for cylinder (i) at combustion event (k+1) based on anti-correlation with the detected acceleration and spill-over effects from fueling.