Abstract: A forward flow region in which forward intake air currents are produced and a reverse flow region in which reverse intake air currents are produced are formed in the throttle bore of a throttle body 3 included in an internal-combustion engine, and the boundary between those regions extends below a throttle valve 5. A fuel vapor control system for an internal-combustion engine has a purge tube 13 joined to the throttle body 3 to supply fuel vapor into the throttle body 3 and is provided with an opening 22 which acts as a purge port. The opening 22 is positioned at a distance from the inner surface 21 of the throttle body 3 defining a throttle bore on the boundary between the forward intake air currents and the reverse intake air currents. Fuel vapor jetted through the opening 22 of the purge tube 13 into the throttle bore flows toward an intake manifold 2, diffusing into both the forward intake air currents and the reverse intake air currents from the boundary between the intake air currents.

Abstract: An apparatus for controlling a control parameter of a multicylinder internal combustion engine so that a cycle-by-cycle torque variation is equal to a target torque variation after an inter-cylinder correction for bringing the quantities of torque generated in a plurality of cylinders into agreement is performed. In the engine control apparatus, a modification part modifies a range within which a torque variation correction factor can change into a narrower range, when it is judged that the inter-cylinder correction has not been completed, so that a control part generates an appropriate control parameter based on first correction factors calculated by a first calculation part and the torque variation correction factor calculated by a second calculation part even when the inter-cylinder correction routine has not been completed.

Abstract: An engine control apparatus for controlling a control parameter of an internal combustion engine equipped with an automatic transmission using a torque converter with a lock-up clutch.

Abstract: An evaporative fuel control apparatus of an internal combustion engine is provided with a purge correction prohibition part. The apparatus includes a detection part for detecting operating conditions of the internal combustion engine and for supplying signals indicative of the operating conditions, a purge control valve for controlling a flow of fuel vapor to an intake passage of the engine, a calculation part for calculating a fuel injection amount in response to the signals, and a fuel injection control part for varying a feedback correction factor of an air-fuel ratio in response to the signals so as to maintain the air-fuel ratio at a stoichiometric value and for correcting the fuel injection amount on the basis of the feedback correction factor.

Abstract: An evaporative fuel control apparatus of an internal combustion engine for controlling a purge correction amount and a fuel injection amount in response to a concentration of fuel vapor in intake mixture. The apparatus includes a detection part for detecting operating conditions of the engine and for supplying signals indicative of the operating conditions, a purge valve for controlling a flow of fuel vapor from a fuel tank to an intake passage, and a calculation part for calculating the fuel injection amount in response to the signals.

Abstract: A diagnosis device of an exhaust gas recycling device of an internal combustion engine checks operating conditions of the engine and determines whether the engine is operating with performance of exhaust gas recycling based upon the checked conditions by modifying them according to atmospheric pressure.

Abstract: An engine having a fuel injector for normally feeding a lean air-fuel mixture into the engine cylinders. Ignition timing is determined so that it is suitable for the lean air-fuel mixture. The gear changing operation of the transmission of the engine is detected from the change in the engine speed and the change in the absolute pressure in the intake passage. When the gear changing operation is carried out, a rich air-fuel mixture is fed into the engine cylinders, and the ignition timing is retarded.

Abstract: An ignition timing control apparatus for a spark ignition internal combustion engine for a vehicle having a manually operated transmission system. The apparatus includes an ignition control system for controlling ignition timing in such a manner that the timing is advanced when the engine speed drops due to engagement of the clutch of the transmission apparatus to begin the initial movement of the vehicle. The drop in the engine speed is sensed by detecting whether a second order difference value of the engine speed is lower than a reference value. This realizes quick control of the engine speed.

Abstract: Synchronous fuel injection amount of injected from a fuel injector in synchronization with rotation of an engine is controlled in relation to the second time differential of either the intake pipe pressure or intake flow rate.

Abstract: Fuel is injected in synchronism with the crank angle. In addition, an engine acceleration state is detected from the second-order differential value of the intake-pipe pressure, and the quantity of the asynchronous fuel injection in which fuel is injected in asynchronism with the crank angle is increased in an early stage of acceleration but is decreased after the early stage of acceleration. Moreover, no asynchronous injection is carried out in a low engine speed region. It is thereby possible to obtain an optimum air-fuel ratio in accordance with the engine acceleration state.