Abstract: A device for controlling an internal combustion engine, comprising a variable valve mechanism for varying opening areas (valve lift) or the working angles (valve-opening periods) of at least either the intake valves or the exhaust valves, wherein a pressure in the cylinder is calculated based on the opening area or the working angle of at least either the intake valve or the exhaust valve varied by the variable valve mechanism, and the internal combustion engine is controlled based on the pressure in the cylinder. Upon calculating the pressure in the cylinder based on the opening areas or the working angles of the intake and exhaust valves, it is possible to more suitably control the internal combustion engine based not only upon the peak combustion pressure in the cylinder like when a combustion pressure sensor is used but also upon a pressure in the cylinder at a moment other than the peak combustion pressure.

Abstract: An idle speed control device for an internal combustion engine controls an idle speed of the internal combustion engine by at least one of an amount of intake air and an ignition timing during application of an external load. The control device calculates a target amount of air corrected by the external load, estimates a transient speed of the internal combustion engine when changing the amount of intake air to the target amount of air, and further corrects the amount of intake air or corrects the ignition timing on the basis of a difference between the estimated speed and the actual speed of the internal combustion engine at the timing when the speed is estimated, in such a manner as to reduce the difference. If the external load changes, the control device corrects the amount of intake air so as to maintain the engine speed, and prevents the engine speed from fluctuating due to a delay of response in such a case.

Abstract: An evaporated fuel processing apparatus for an internal combustion engine is provided which includes a canister that traps fuel vapors generated in a fuel tank, and a purge control valve disposed between the canister and an intake passage of the internal combustion engine. A controller of the apparatus determines (a) a quantity of purge gas that passes through the purge control valve, (b) a fuel injection amount correction coefficient for reducing a deviation of an actual air-fuel ratio from a target air-fuel ratio due to the purge gas, (c) a fresh air ratio that represents a ratio of purge air contained in the purge gas to the purge gas, based on the fuel injection amount correction coefficient, and (d) a quantity of the purge air based on the quantity of the purge gas and the fresh air ratio. The controller then controls the internal combustion engine based on the quantity of the purge air.

Abstract: An idle speed control device for an internal combustion engine controls an idle speed of the internal combustion engine by at least one of an amount of intake air and an ignition timing during application of an external load. The control device calculates a target amount of air corrected by the external load, estimates a transient speed of the internal combustion engine when changing the amount of intake air to the target amount of air, and further corrects the amount of intake air or corrects the ignition timing on the basis of a difference between the estimated speed and the actual speed of the internal combustion engine at the timing when the speed is estimated, in such a manner as to reduce the difference. If the external load changes, the control device corrects the amount of intake air so as to maintain the engine speed, and prevents the engine speed from fluctuating due to a delay of response in such a case.

Abstract: An evaporated fuel treatment device comprising a purge control valve for controlling an amount of fuel vapor fed into the intake passage from a charcoal canister, wherein the pressure in the fuel vapor chamber of the canister is detected and wherein the vapor concentration, which is one of the values for correction of the amount of fuel injection, is increased when the pressure in the fuel vapor chamber increases while the purge operation is stopped.

Abstract: In an evaporated fuel treatment device for an internal combustion engine, various parameters indicating that an engine is currently in a state where a fuel vapor is generated from a fuel tank are detected from moment to moment to estimate in advance that the amount of the fuel vapor is generated more than a capacity of the canister. Then, the purge from the canister is promoted on the basis of that estimation so that the fuel vapor of more than the capacity of canister is prevented from being adsorbed by the canister. With this structure, the overflow of the fuel vapor from the canister is prevented, and also the evaporative emission is suppressed.

Abstract: An evaporated fuel treatment device comprising a purge control valve arranged between a canister and an intake passage of an engine. A drive pulse of the purge control valve is controlled by a duty ratio. When the engine operating state is one in which a large amount of evaporated fuel is produced in the fuel tank, the feedback correction coefficient is maintained at a is position deviated from the reference value so as to enable the feedback correction coefficient to change in accordance with the fluctuations of the air-fuel ratio.

Abstract: An evaporated fuel treatment device comprising a purge control valve for controllling an amount of fuel vapor fed into the intake passage from a charcoal canister. At the time of restarting a purge action, the purge action is restarted by a low purge rate when the concentration of the fuel vapor to be purged into the intake passage rose to a predetermined concentration while the purge action was stopped and the engine was idling.

Abstract: An evaporated fuel treatment device comprising a purge control valve for controlling an amount of fuel vapor fed into the intake passage from a charcoal canister. The drive pulse of the purge control valve is controlled by a duty ratio. When the engine is idling, if the air-fuel ratio becomes rich, the speed of increase of the duty ratio of the drive pulse of the purge control valve is restricted to less than a predetermined speed.

Abstract: It is an object of the invention to control the fluctuation in an air-fuel ratio in a multicylinder internal combustion engine when the driving period of a purge control valve is substantially synchronized with an engine cycle, thereby better purifying exhaust gas and preventing lean misfires.

Abstract: An evaporated fuel treatment device comprising a purge control valve for controlling an amount of fuel vapor fed into the intake passage from a charcoal canister. The purge action of the fuel vapor is temporarily stopped and then restarted. The purge action is restarted by the purge rate of just before the purge action was stopped when the engine load at the time of the restart of the purge action is higher than a predetermined set load, while the purge action is restarted by a purge rate lower than a predetermined purge rate when the engine load at the time of the restart of the purge action is lower than the set load.

Abstract: An evaporated fuel treatment device comprising a purge control valve arranged between a canister and an intake passage of an engine. A drive pulse of the purge control valve is controlled by a duty ratio. When the purge action starts, the duty ratio is gradually increased. When the amount of the intake air is large other than at engine idling, the purge action is started. After the purge action is started, the purge action is performed even during engine idling.

Abstract: An evaporated fuel treatment device comprising a purge control valve arranged between a canister and an intake passage of an engine. A drive pulse of the purge control valve is controlled by a duty ratio. When the purge action starts, the duty ratio is gradually increased. In the region of a small duty ratio where the flow rate of the purge control valve becomes unstable, the duty ratio is either increased or else held constant so that the duty ratio is not allowed to fall.

Abstract: An object of the present invention is to improve the performance of purifying an exhaust gas by suppressing the variation of the air-fuel ratio of an engine occurring when the rotation cycle of the engine is substantially synchronous with the drive cycle of a purging control valve, and to prevent misfiring caused by a lean air-fuel mixture.

Abstract: An apparatus for processing evaporated fuel produced in a fuel tank for a multicylinder engine evenly distributes purged fuel to each cylinder of the engine.The apparatus has a canister 25 for adsorbing the evaporated fuel and a purge pipe 26 for connecting the canister to an intake duct and purging the adsorbed fuel into the intake duct. The purge pipe 26 has purge ports 1 and 2 that are open in the intake duct at different positions involving different velocities of intake air. The purge pipe 26 may have means for adjusting a flow time of purged fuel passing through the purge pipe. The purge ports may be arranged to produce a swirl of purged fuel in the intake air.

Abstract: An evaporative control system for a multicylinder internal combustion engine makes the driving period of a purge control valve for asynchronous to an engine cycle when controlling purged fuel, to keep an air-fuel ratio in the engine stabilized, improve exhaust purifying performance, and prevent lean misfires.The engine has a canister for storing evaporated fuel from a fuel tank, a purge pipe for connecting the canister to an intake duct of the engine, and a purge control valve disposed in the purge pipe. A driving period changing unit sequentially changes the driving period of the purge control valve from one to another, or changes it so that the start of the driving period may not continuously agree with a crank angle of the engine. A valve controlling unit opens and closes the purge control valve according to the driving period set by the driving period changing unit. A duty factor setting unit sets a minimum valve open time for the purge control valve. A timer unit measures an interval of purge control.

Abstract: A fuel-vapor treatment method and apparatus for an internal combustion engine, wherein when the density of fuel vapor emitted directly from a fuel tank is higher than the density of fuel vapor emitted from a canister, provisions are made to prevent the density of the mixture of these vapors purged into an intake passage from varying substantially, thereby suppressing perturbations in air-fuel ratio. When purge execution time becomes long, the energization of a solenoid valve used to control the amount of purge gas from the canister is limited to keep the maximum/minimum amount of purge gas or the amount of change thereof within a prescribed range. This serves to suppress the variation in purge gas amount, and hence the variation in vapor density, that may occur during a transition from idling to driving (in the increasing direction of the purge gas amount) or during a transition from driving to idling (in the decreasing direction of the purge gas amount).

Abstract: A fuel supply control device for an engine comprises a canister in which fuel vapor is temporarily stored and from which fuel vapor is purged into the engine. When the throttle valve is in the idling position and when the engine speed N is higher than the first reference speed N1, the fuel injection and the purging operation are stopped. During the stoppage of the fuel injection and the purging operation, if the throttle valve is out of the idling position or if the engine speed N is lower than the second reference speed N2, the fuel injection and the purging operation are restarted. The reference speeds N1 and N2 are set to become higher when the storing capacity of the canister becomes lower.

Abstract: This fuel injection control apparatus consists of a calculating device for calculating an air-fuel ratio correction factor FAF, a learning device for learning an air-fuel ratio learning factor KG in accordance with the deviation of FAF from the reference value, and a controller for controlling the amount of injected fuel in accordance with FAF and KG. When the start enrichment FASE and the warm-up enrichment FWL are added, KG is learned in accordance with the corrected deviation which is the deviation of FAF corrected by the correction factor f(FASE+FWL) which is concerned with FASE and FWL. The learning accuracy is improved because KG is learned at each region of FWL which is divided into plural regions in accordance with the engine driving conditions.

Abstract: A fuel emission control device for an engine comprises an adsorbent for temporarily adsorbing fuel vapor therein. A canister for housing the adsorbent therein is connected to a fuel tank via a fuel vapor passage, through which fuel vapor in the fuel tank is introduced into the canister. The canister is also connected to an intake passage downstream of a throttle valve via a purge passage, through which fuel vapor adsorbed in the adsorbent is purged into the intake passage. When an amount of fuel vapor to be introduced to the canister becomes larger, the effective volume of the adsorbent interposed between the fuel vapor passage and the purge passage is made larger.