Abstract: An apparatus and method for detecting an intake air mass flow rate using a Karman vortex air flow arranged in an intake passage of an internal combustion engine, in accordance with the formula:.gamma.(x)=.gamma.(760).times.V.sub.p (x)/V.sub.p (760)where .gamma.(x) is an intake air density to be obtained; .gamma.(760) is the air density under standard atmospheric pressure, V.sub.p (x) is the amplitude value of the analog signal obtained from the Karman vortex air flow sensor; and V.sub.p (760) is the amplitude value of the analog signal under standard atmospheric pressure.

Abstract: A fuel injection control method for an internal combustion engine in which asynchronous fuel injection can be carried out in accordance with the change in the number of engine rotations and throttle valve opening and asynchronously with the rotations of a crank shaft within a predetermined range of the number of engine rotations while inhibiting the asynchronous fuel injection when the number of engine rotations is not within the range, whereby the lean and over rich conditions of the air/fuel ratio which often occurred in the conventional method for controlling fuel injection can be prevented and acceleration with a good response can be realized.

Abstract: In an electronic fuel injecting method for an internal combustion engine, wherein fuel injection timings for every groups are controlled in accordance with reference signals variable in the proximity of intake top dead center of a predetermined cylinder and the angle signals variable at every predetermined rotary angles, during a low rotational speed operation of the engine, all of the cylinders perform injections simultaneously in accordance with the angle signals according to the necessity, during a medium rotational speed operation of the engine, group injections with the cylinders being discriminated by the reference signal are performed in accordance with the reference signals and the angle signals, and, during a high rotational speed operation of the engine, group injections with the cylinders being not discriminated by the reference signal are performed in accordance with the angle signals according to the necessity.

Abstract: A method for controlling, according to the L-jetronic fuel injection principle, an internal combustion engine with a fuel injection valve fitted to its intake manifold, and an intake air flow meter. Repeatedly a first quantity representing the desired amount of fuel to be provided to the combustion chambers of the engine during the time period between the next two fuel injection pulse time points is determined, based upon sensed values of certain operational parameters including intake air flow, and a second quantity is determined as the time smoothed value of the first quantity. Optionally further the second quantity may be modified according to engine operational parameters. Simultaneously, at proper injection time points in the engine's operational cycle, the fuel injection valve is opened for a time corresponding to a third quantity which is calculated from the second quantity. A device is also explained, incorporating an electronic computer, which practices this method.

Abstract: The volumetric efficiency of an internal combustion engine is calculated from the detected flow rate of the intake air and from the detected rotational speed. The changing rate of the calculated volumetric efficiency is restricted to a limit rate. Then, the amount of fuel to be injected into the engine is calculated, depending upon the restricted volumetric efficiency.

Abstract: Engine parameter signals indicative of the operating condition of the engine and an air-fuel ratio signal indicative of whether the air-fuel ratio condition of the engine is on the rich side or the lean side relative to a stoichiometric condition are produced. When the engine operates under a predetermined state, the fuel feeding rate to the engine is controlled in response to the engine parameter signals and the air-fuel ratio signal, by a closed loop control operation, in order to determine a learning control correction factor F.sub.G. In the closed loop control operation, a feedback correction factor F.sub.B is calculated depending upon the air-fuel ratio signal, and the fuel feeding rate is corrected depending upon the calculated factor F.sub.B, so as to control the air-fuel ratio condition to a condition close to the stoichiometric condition. At the same time, the learning control correction factor F.sub.G is adjusted, so as to settle the feedback correction factor F.sub.