Abstract: A fuel control unit and a fuel injection control method for a multi-cylinder engine adjust the pulse width of asynchronous injection so as to set the air-fuel ratio of a fuel-air mixture in a first cylinder to 17 or more but under 21 if it is determined according to an engine speed (Ne) that an engine is in an idling mode and if it is determined according to the opening of a throttle valve that a condition for starting the acceleration of the engine has been satisfied. The foregoing first cylinder is the cylinder in which compression pressure increases first following the determination described above.

Abstract: An engine control system for controlling operation of an engine of a type injecting fuel directly into a combustion chamber in different injection modes according to engine operating conditions has a map of engine control values with respect to specified engine operating conditions at intersection points of a grid pattern in which engine control values at extreme intersection points adjacent to a boundary between adjacent injection modes is discontinual. The engine control system calculates an engine control value for an engine operating condition by interpolation with the aid of engine control values at the intersection points and determines an engine control value for an engine operating condition at a point closer to the boundary than the extreme intersection point of one injection mode based on engine control values at intersection points of the one injection mode only.

Abstract: An engine control system for an automobile engine of, for example, the type which injects fuel directly into an combustion chamber (16) and executes a fuel-cut control under a specified engine operating condition establishes a stratified charge combustion mode and a homogeneous charge combustion mode selectively according to engine operating conditions following termination of the fuel-cut control and shuts off nearly completely an engine throttle valve (28) during execution of the fuel-cut control and opens the engine throttle valve (28) so as to variably control an amount of intake air passing through an intake passage (24) into the combustion chamber (16) before the stratified charge combustion mode is established following termination of the fuel-cut control.

Abstract: During an air-fuel ratio feedback control based on an oxygen concentration in exhaust gases which converges an air-fuel ratio toward a target ratio suitable for a satisfactory purifying efficiency of a catalyst, the air-fuel ratio is coercively deflected so as to make a fuel mixture richer and leaner alternatively. An extent of deflection of the air-fuel ratio is set larger before the catalyst has not yet been activated sufficiently.

Abstract: An air-fuel ratio control system for a gaseous fuel engine which runs on gaseous fuel containing at least partly hydrogen gas has a fuel supply control valve which adjusts the amount of the gaseous fuel supplied to the engine and a control unit which controls the fuel supply control valve to control the air-fuel ratio according to the engine load. The control unit controls the fuel supply control valve so that the air-fuel ratio becomes higher than a NOx-maximizing air-fuel ratio, at which the amount of NOx emitted from the engine is maximized, in a predetermined operating range of the engine, and in the predetermined operating range of the engine, the control unit controls the fuel supply control valve so that the air-fuel ratio becomes higher in a high engine speed range than in a low engine speed range.

Abstract: An air-fuel ratio control apparatus for an alcohol engine driven by fuel containing an alcohol component, where oxygen density of the exhaust gas is detected by an O.sub.2 sensor and an air-fuel ratio is controlled to approach a theoretical air-fuel ratio in response to the oxygen density detected by the O.sub.2 sensor, is disclosed. The apparatus comprises an engine load detecting means for detecting engine load, and a control unit for correcting the air-fuel ratio to be rich in response to engine load such that the degree of the correction becomes larger as the engine load becomes small.

Abstract: An engine induction system includes intake passages connected to inlet ports of an engine, an injector provided in the intake passage for injecting fuel in an intake plenum between the injector and the inlet port, the injector being disposed in such a position that the volume of the intake plenum is greater than the predetermined stroke volume. This ensures improved vaporization and atomization of fuel and mixing of fuel and air, and improves the combustibility and increases the charging efficiency of use of latent heat of vaporization.

Abstract: An intake system for a multi-cylinder internal combustion engine having an intake manifold that is made up of a common intake passage and separate intake passages that branch off from the common intake passage and connect to intake ports of the engine cylinders. An upstream throttle valve is located in the common intake passage. Downstream throttle velves located in the separate branched intake passages near the intake ports. A controller controls intake air actually introduced into the cylinder by actuating the downstream throttle valves to throttle down, smaller than the upstream throttle valve in a light engine load range and by actuating the upstream throttle valve to throttle down smaller than the downstream throttle valves in a heavier engine load range.

Abstract: An air-fuel ratio control system for an engine in which a fuel injection amount is calculated according to the engine operating conditions and is corrected according to the output of an air-fuel ratio sensor, comprises a base fuel injection amount calculating section for calculating a base fuel injection amount corresponding to the stoichiometric air-fuel ratio on the basis of the intake air amount, a target air-fuel ratio calculating section for calculating a target air-fuel ratio according to the engine operating condition, a reference value calculating section for calculating a reference value which represents the target air-fuel ratio and is submitted to comparison with the output of the air-fuel ratio sensor, a feedback correction coefficient calculating section for calculating a feedback coefficient according to the deviation of the output of the air-fuel ratio sensor from the reference value, and a final fuel injection amount calculating section which corrects the base fuel-injection amount on the basi

Abstract: An air-to-fuel ratio control system for an internal combustion engine comprises means for performing a feedback control for keeping a fuel mixture to have the theoretical air-to-fuel ratio or approximations thereof in response to the output of an air-to-fuel ratio sensor, means for conducting the learning to compute a supplemental feedback quantity of fuel used for revising the quantity of fuel by which the fuel actually supplied is determined in at least one of partitions of the operating condition of the engine under the feedback control, means for memorizing the supplemental feedback quantity of fuel in at least one of memorizing areas partitioned in accordance with the partitions of the operating condition of the engine as a resultant of the learning, means for renewing the resultant of the learning in each of the remaining memorizing areas on the strength of the resultant of the learning newly memorized in at least one of memorizing areas, and means for supplying the fuel of the quantity computed with th

Abstract: A knock control system for a supercharged engine comprising a supercharger for providing a super charged air to the engine, an engine condition detector for detecting an engine operating condition, a knock detector for detecting the occurrence of engine knocking, an ignition timing determining unit, a supercharged pressure regulator, an ignition timing correcting unit, and a supercharged pressure correcting unit. The timing determining unit is operable to determine a principle ignition timing in response to an output from the condition detector, and the timing correcting unit is operable in response to an output from the knock detector to adjust the principle ignition timing in the event of occurrence of the knocking.