Abstract: A control system for an internal combustion engine having a plurality of cylinders each having at least one intake valve, at least one exhaust valve, and a crankshaft. The control system has an electromagnetic driving section which electromagnetically causes opening and closing of at least one of the at least one intake valve and the at least one exhaust valve. A crank angle sensor generates a crank angle signal whenever the crankshaft rotates through a predetermined angle, and a cylinder position sensor generates a cylinder-discriminating signal indicative of a predetermined crank angle of a particular cylinder of a plurality of the cylinders. A piston position sensor detects an operating state or position of the piston of each of the plurality of the cylinders, based on the generated crank angle signal and the generated cylinder-discriminating signal.

Abstract: There is provided a catalyst deterioration-detecting system for an internal combustion engine having at least one catalyst arranged in the exhaust passage, for purifying noxious components present in exhaust gases emitted from the engine, and an exhaust gas component concentration sensor arranged in the exhaust passage at a location downstream of the catalyst, for detecting concentration of a specific component in the exhaust gases. An ECU of the system controls the ignition timing of the engine, and detects the degree of deterioration of the catalyst, based on an output value from the exhaust gas component concentration sensor. The ignition timing of the engine is retarded in dependence on the detected degree of deterioration of the catalyst.

Abstract: A fuel injection control system for an internal combustion engine calculates an amount of fuel to be supplied to the engine, based on operating conditions of the engine including at least load on the engine. The system also calculates an amount of fuel adhering to the inner wall surface of the intake passage of the engine, and an amount of fuel to be carried-off from fuel adhering to the inner wall surface, by the use of adhering fuel parameters representative of transfer characteristics of fuel injected into the intake passage. The amount of fuel to be supplied to the engine is corrected according to the amount of fuel adhering to the inner wall surface of the intake passage and the amount of fuel to be carried-off from fuel adhering to the inner wall surface, to thereby calculate a corrected fuel injection amount.

Abstract: An air-fuel ratio control system for an internal combustion engine having at least one catalytic converter arranged in the exhaust passage, comprises an ECU which changes air intake characteristics of the engine, based on operating conditions of the engine, and a plurality of exhaust gas component concentration sensors including at least upstream and downstream exhaust gas component concentration sensors arranged in the exhaust passage at respective locations upstream and downstream of the at least one catalytic converter. The air-fuel ratio of an air-fuel mixture to be supplied to the engine is controlled to a desired air-fuel ratio in a feedback manner responsive to an output from the upstream exhaust gas component concentration sensor. A feedback control parameter for use in the air-fuel ratio feedback control is calculated based on an output from the downstream exhaust gas component concentration sensor.

Abstract: A control system for an internal combustion engine comprises an ECU which calculates an amount of fuel to be supplied to the engine and determines a direct supply ratio and a carry-off ratio, based on operating conditions of the engine. The direct supply ratio is a ratio of a fuel amount directly drawn into the engine in a predetermined operating cycle of the engine to the whole fuel amount injected in the same operating cycle, and the carry-off ratio is a ratio of a fuel amount carried off the inner surface of the intake pipe and drawn into the engine in the predetermined operating cycle to the whole fuel amount which adhered to the inner surface of the intake pipe in an operating cycle immediately preceding the predetermined operating cycle.

Abstract: A fuel injection control system for an internal combustion engine comprises an ECU which calculates a direct supply ratio and a carry-off ratio, and detects a predetermined operating condition of the engine in which an increased amount of fuel is to be supplied to the engine. When the predetermined operating condition is detected, a plurality of fuel injection amounts to be sequentially injected by at least one fuel injection valve are calculated based on operating conditions of the engine, the direct supply ratio and the carry-off ratio. Then, an amount of fuel adhering to the intake system of the engine is calculated based on the total sum of the calculated plurality of fuel injection amounts, as well as on the calculated direct supply ratio and the calculated carry-off ratio. At least one of the calculated plurality of fuel injection amounts is corrected based on the calculated amount of fuel adhering to the intake system.

Abstract: An air-fuel ratio control system for an internal combustion engine includes a LAF sensor and an O2 sensor arranged in an exhaust pipe at respective locations upstream and downstream of a catalytic converter. A desired air-fuel ratio coefficient used in calculating an amount of fuel supplied to the engine is calculated based on operating conditions of the engine, and corrected based on output from the O2 sensor. The air-fuel ratio of a mixture supplied to the engine is feedback-controlled to a stoichiometric air-fuel ratio based on the corrected desired air-fuel ratio coefficient. When the output from the O2 sensor falls within a predetermined range, the desired air-fuel ratio coefficient is not corrected, but held at an immediately preceding value thereof.

Abstract: A control system for an internal combustion engine determines whether or not at least one of fuel cut which is cutting-off of supply of fuel to the engine and decreased fuel supply which is supplying of fuel to the engine in a decreased amount for deceleration of the engine has been started, and whether or not purging of evaporative fuel into an intake passage of the engine by an evaporative emission control system of the engine was carried out within a first predetermined time period before the at least one of the fuel cut and the fuel supply reduction for deceleration of the engine has been stated. The amount of auxiliary air supplied to the engine via a secondary intake air passage bypassing a throttle valve arranged in an intake passage of the engine is increased over a second predetermined time period after the at least one of the fuel cut and the decreased fuel supply for deceleration of the engine has been started.

Abstract: An electromagnetically driven valve control system for an internal combustion engine having at least one intake valve and at least one exhaust valve, and a starter for starting cranking of the engine. A CPU controls an energization time/timing control circuit section to electromagnetically drive at least one of the at least one intake valve and the at least one exhaust valve. The CPU detects a starting signal indicative of starting of the cranking of the engine, and a timer measures a time period elapsed after the starting signal is detected. An inhibiting time period is set, over which the operation of the starter means is inhibited, and the at least one of the at least one intake valve and the at least one exhaust valve is driven in a valve closing direction when the starting signal is detected. The operation of the starter is permitted when the time period elapsed after the starting signal is detected exceeds the inhibiting time period.

Abstract: A fuel injection control system for an internal combustion engine calculates an amount of fuel to be supplied to the engine, based on operating conditions of the engine including at least load on the engine. The system also calculates an amount of fuel adhering to the inner wall surface of the intake passage of the engine, and an amount of fuel to be carried-off from fuel adhering to the inner wall surface, by the use of adhering fuel parameters representative of transfer characteristics of fuel injected into the intake passage. The amount of fuel to be supplied to the engine is corrected according to the amount of fuel adhering to the inner wall surface of the intake passage and the amount of fuel to be carried-off from fuel adhering to the inner wall surface, to thereby calculate a corrected fuel injection amount.

Abstract: An ignition timing control system for an internal combustion engine is associated with a fuel injection amount control system for calculating an amount of fuel to be supplied to the engine, based on operating conditions of the engine, correcting the calculated amount of fuel, based on an adherent amount of fuel adhering to the inner wall surface of the intake passage, and a carried-off amount of fuel to be carried off from the adherent fuel into each combustion chamber of the engine, and injecting the corrected fuel amount into the intake passage. The ignition timing control system comprises an ECU which detects whether the engine has been recovered from a fuel cut state to a fuel supply state, and calculates ignition timing of the engine, based on operating conditions of the engine detected by engine operating parameter sensors, including pressure within the intake passage.

Abstract: A control system for an internal combustion engine calculates an amount of fuel to be supplied to the engine based on load on the engine, and estimates an amount of fuel adhering to an inner wall surface of an intake passage of the engine and an amount of fuel carried off the fuel adhering to the inner wall surface of the intake passage, based on an adherent fuel-determining parameter indicative of a fuel transfer characteristic of the engine. The amount of fuel to be supplied to the engine is corrected based on the amount of fuel adhering to the inner wall surface of the intake passage and the amount of fuel carried off the fuel adhering to the inner wall surface of the intake passage to determine a corrected amount of fuel supplied to the engine. The corrected amount of fuel to be supplied to the engine is injected into the intake passage. The timing of the fuel injection is controlled based on the adherent fuel-determining parameters.

Abstract: A control system according to one aspect calculates a ratio of an actual amount of fuel supplied to the combustion chamber to the desired amount of fuel to be supplied to the combustion chamber, by taking into account at least an amount of evaporative fuel supplied to the combustion chamber, and sets the rate of change of the air-fuel ratio correction coefficient based on this ratio of the actual amount to the desired amount. A control system according to another aspect of the invention calculates an injected fuel ratio of an amount of fuel injected to an amount of total fuel to be supplied to the combustion chamber, and controls the ignition timing based on the injected fuel ratio and depending on operating conditions of the engine.

Abstract: An air-fuel ratio control system for an internal combustion engine controls an amount of fuel supplied to the engine. Operating conditions of the engine, including engine rotational speed and intake pressure, are detected. Also detected is a valve opening of a recirculation control valve arranged in an exhaust recirculation passage, for controlling recirculation of exhaust gases. An amount of recirculation gas is determined based on a detected value of the valve opening of the recirculation control valve. A fuel supply amount is calculated based on the engine rotational speed and the intake pressure. The fuel supply amount is corrected based on the amount of recirculation gas determined.

Abstract: An air-fuel ratio control system for an internal combustion engine detects a central value of an output from a first exhaust gas component concentration sensor arranged in an exhaust passage at a location upstream of a catalytic converter and having an output characteristic which is substantially proportional to the concentration of a component in the exhaust gases. The central value is corrected based on the output from the first exhaust gas component concentration sensor, when an output from a second exhaust gas concentration sensor arranged downstream of the catalytic converter falls within a predetermined range. The output from the first exhaust gas component concentration sensor is corrected based on the corrected central value. An air-fuel ratio of a mixture supplied to the engine is corrected based on the corrected output value from the first exhaust gas component concentration sensor.

Abstract: An air-fuel ratio control system for an internal combustion engine includes a LAF sensor and an O2 sensor arranged in an exhaust pipe at respective locations upstream and downstream of a catalytic converter. A desired air-fuel ratio coefficient used in calculating an amount of fuel supplied to the engine is calculated based on operating conditions of the engine, and corrected based on output from the O2 sensor. The air-fuel ratio of a mixture supplied to the engine is feedback-controlled to a stoichiometric air-fuel ratio based on the corrected desired air-fuel ratio coefficient. When the output from the O2 sensor falls within a predetermined range, the desired air-fuel ratio coefficient is not corrected, but held at an immediately preceding value thereof.

Abstract: A control system for an internal combustion engine according to one aspect of the invention calculates a total amount of evaporative fuel purged from a canister based on dynamic characteristics and concentration of purged gas. The system calculates an amount of evaporative fuel supplied to the combustion chamber of the engine based on the total amount of evaporative fuel and depending on dynamic characteristics of the purged gas. Then, the system determines a required amount of fuel to be injected by a fuel injection valve based on the amount of evaporative fuel supplied to the combustion chamber.

Abstract: A control system for controlling operation of an internal combustion engine detects a selected one of two exhaust modes: a first exhaust mode in which exhaust gases are guided through a first catalytic converter upstream of a second catalytic converter, and a second exhaust mode in which exhaust gases are guided through a bypass passage bypassing the first catalytic converter. A control mode is determined according to the selected one of the two exhaust modes, in which the operation of the engine is to be controlled by the control system.

Abstract: A control system for an internal combustion engine estimates an amount of adherent fuel adhering to the inner surface of the intake passage, as well as an amount of carried-off fuel evaporated form fuel adhering to the inner surface of the intake passage and carried into combustion chambers, determines an amount of supply fuel to be supplied to the engine, based upon operating conditions of the engine, the estimated adherent fuel amount, and the estimated carried-off fuel amount, and supplies the determined supply fuel amount into the intake passage. The control system calculates an amount of exhaust gases to be recirculated from the exhaust passage to the intake passage, and corrects the estimated adherent fuel amount and the estimated carried-off fuel amount, based upon the calculated exhaust gas recirculating amount, based upon the calculated exhaust gas recirculating amount.

Abstract: A catalyst deterioration-detecting device for an internal combustion engine has at least one catalyst arranged in an exhaust passage of the engine,for purifying exhaust gases emitted from the engine, first and second exhaust component concentration sensors arranged in the exhaust passage upstream and downstream of the catalyst, respectively. The catalyst deterioration-detecting device calculates an average value of an output value from the second exhaust component concentration sensor, calculates an output fluctuation width with respect to the average value, based on the output value from the second exhaust component concentration sensor, and determines whether the catalyst is deteriorated, based on the calculated average value and the calculated output fluctuation width. The detection of the catalyst deterioration is carried out when the engine is in a predetermined operating condition defined by engine temperature, engine speed and engine load.