Abstract: A method of proportional deceleration fuel lean-out for an internal combustion engine includes the steps of sensing a throttle position of a throttle for the engine with a throttle position sensor, calculating a throttle proportional deceleration fuel lean-out multiplier (LOTHR) value based on the sensed throttle position, sensing a manifold absolute pressure (MAP) of an intake manifold for the engine with a MAP sensor, calculating a MAP proportional deceleration fuel learn-out multiplier (LOMAP) value based on the sensed MAP, combining the LOTHR and LOMAP values and calculating an overall proportional deceleration fuel lean-out multiplier (LOMULT) value, and applying the calculated LOMULT value to a fuel pulsewidth value of fuel injectors for the engine and reducing the amount of fuel injected into the engine by the fuel injectors.

Abstract: The first mixing ratio error in a transient state is sampled as a pre-transient error, the last mixing ratio error in the transient state is sampled as a post-transient error, and the peak value of the mixing ratio errors in the transient state is also sampled. The difference between either this pre-transient mixing ratio error or post-transient mixing ratio error depending on whichever is the nearer to a peak value, and the peak value of said mixing ratio errors, is computed. Injection fuel correction amounts in transient running states are learned and the learned values are stored in a memory so as to eliminate this difference. By correcting the injection fuel amounts based on these learned values in transient running states, the effect of steady state errors on the transient learning precision is eliminated and instantaneous lean peaks in the air-fuel ratio are smoothed out.

Abstract: An air-fuel controller for a water-cooled engine provided with a mechanism for detecting a mixing ratio error which is a difference between a target mixing ratio and a real mixing ratio of fuel and air provided for the engine, a mechanism for performing learning related to a fuel injection amount based on the detected mixing ratio error, a memory for storing this learned value, a mechanism for computing a fuel injection correction amount based on this learned value, and a mechanism for outputting a fuel injection amount corrected by this correction amount to the fuel injector. This engine may be provided for example with a mechanism to set the difference between the mixing ratio error in the transient state and after the transient state has terminated as a transient mixing ratio error, and a mechanism to update the learned value stored in the memory such that the transient mixing ratio error is minimized. In this manner, learning precision in air-fuel ratio control is improved.

Abstract: An electronic system for controlling the fuel injection of an internal-combustion engine based on the load, rotational speed, and temperature, as well as at least an oxygen probe reading in the exhaust pipe. The system determines basic injection-quantity signal as well as a transition-compensation signal to adapt the injection fuel quantity in situations of acceleration and deceleration. The system stores an engine characteristics map for a wall-film-quantity signal, and dividing factors for acceleration and deceleration. The system generates a correction value (Wkor) for the wall-film quantity signal and correction factors (FWS1kor, FWS2kor) for the two dividing factors. Three methods are provided for changing the correction factors in connection with the adaptation and these are based on a direct calculation, based on an estimation of the missing quantity and incremental calculation, and based on an incremental adjustment based on the evaluation of the oxygen-probe voltage.

Abstract: In a steady operating condition of an engine, the fuel supply quantity is changed compulsorily and step-by-step, and in compliance with changing conditions of the fuel quantity sucked into cylinders after such correction of the fuel supply quantity, a fuel adhesion ratio and an evaporation ratio as the decisive parameters for a wall flow quantity of fuel are learned separately in each operational region, and using the learned results the fuel supply quantity in transitional operation is corrected.