Abstract: A misfire detector prevents catalysts from being heated to damaging high temperatures. The misfire detector for a multi-cylinder engine includes a fuel cut control to stop supplying fuel to misfiring cylinders, a control to prevent a fuel feed back control and a fuel learning control and to initialize the correction values of both the fuel feed back control and the fuel learning control, and a retard control to retard the ignition timing based on the extent that misfire occurs or the air-fuel ratio. The retard control can be replaced by a throttle opening control for misfire to limit the throttle opening angle. The retard control can also be replaced by an engine or vehicle speed control to limit the engine or vehicle speed below a predetermined engine or vehicle speed, respectively, irrespective of the throttle position.

Abstract: The purpose of the present misfire detector is to prevent catalysts from being heated to high temperatures, thereby avoiding detriment or damage of the catalysts. The misfire detector for a multi-cylinder engine includes (1) a fuel cut control for misfire cylinders by a fuel cut means to stop supplying the fuel to the misfire cylinders, (2) a control to prevent a fuel feed back control and a fuel leaning control and to initialize the correction values of both the fuel feed back control and the fuel leaning control, and (3) a retard control to retard the ignition timing by a retard quantity set based on the extent the misfire occurs or the air-fuel ratio. The above control (3) can be replaced by a throttle opening control for misfire to limit the throttle opening angle as compared to a normal opening in accordance with the acceleration degree.

Abstract: This invention provides an evaporative fuel control system for an internal combustion engine which system comprises an intake passage and a canister in communication with a fuel tank. The canister includes more than one chamber with activated carbon provided to absorb evaporative fuel. In this system, the canister is connected to the atmosphere via an open passage which is controlled by the atmosphere open/close valve situated in the open passage. The canister is also connected to the intake passage via a purge passage. The purge passage is controlled via a purge valve situated in the purge passage. The evaporative fuel control system comprises further a purge concentration detector which detects the concentration of a purge taken into the engine and a controller which diagnoses leakage after a predetermined amount of time set according to the concentration of the purge detected by the purge concentration detector.

Abstract: This invention provides an evaporative fuel control system for an internal combustion engine which system comprises an intake passage and a canister in communication with a fuel tank. The canister includes more than one chamber with activated carbon provided to absorb evaporative fuel. In this system, the canister is connected to the atmosphere via an open passage which is controlled by the atmosphere open/close valve situated in the open passage. The canister is also connected to the intake passage via a purge passage. The purge passage is controlled via a purge valve situated in the purge passage. The evaporative fuel control system comprises further a purge concentration detector which detects the concentration of a purge taken into the engine and a controller which diagnoses leakage after a predetermined amount of time set according to the concentration of the purge detected by the purge concentration detector.

Abstract: A heater controller for an oxygen sensor associated with a vehicle engine. The controller includes a start detect section, a restart determination section, and a heater delay control section. The start detect section detects whether the engine is started. The restart determination section determines whether the engine is restarted. The heater delay control section operates the heater to activate after a predetermined delay time, delayed from startup of the engine, that is set according to an engine water temperature. The operation of the heater is executed when the start detect section detects that the engine is started and the restart determination section determines that the engine is not restarted.

Abstract: A heater controller for an oxygen sensor associated with a vehicle engine. The controller includes a start detect section, a restart determination section, and a heater delay control section. The start detect section detects whether the engine is started. The restart determination section determines whether the engine is restarted. The heater delay control section operates the heater to activate after a predetermined delay time, delayed from startup of the engine, that is set according to an engine water temperature. The operation of the heater is executed when the start detect section detects that the engine is started and the restart determination section determines that the engine is not restarted.

Abstract: A purge control system of an engine has a purge valve which is opened and closed in accordance with the state of operation of the engine so as to establish a purge-on mode and a purge-off mode, thereby controlling purge rate which is the flow rate of the purge gas supplied to said engine. An air-fuel ratio feedback controller performs feedback control of the air-fuel ratio based on an output signal from an air-fuel ratio sensor and a purge density which is computed as the concentration of the evaporated fuel in the purge gas supplied to said engine. An air-fuel ratio correcting device performs, in the purge-on mode, a purge learning control having a plurality of cycles for learning the results of computations of the purge density and for effecting correction of the air-fuel ratio based on purge learned values obtained through the learning. The air-fuel ratio correcting device effects, in the purge-off mode, correction of the air-fuel ratio based on normal learned values learned in the purge-off mode.

Abstract: An abnormality-diagnosing device for an evaporation purge system and an air-fuel ratio controller for an internal combustion engine having the abnormality-diagnosing device incorporated therein, which device can: prevent misdiagnosis as abnormal, which otherwise would occur under the influence of evaporative fuel caused by altitude, or change or swinging of fuel level or fuel; prevent deviation of an air-fuel ratio from a target value during purging of the evaporative fuel, which otherwise would occur under influence of the evaporative fuel resulting from altitude or fuel level; and, prevent deviation of the air-fuel ratio from the target value when the purge valve is opened, whereby a failure in drivability or aggravation of harmful exhaust component values can be prevented when the evaporative fuel is purged.

Abstract: An air-fuel ratio controlling apparatus for an internal combustion engine allows an air-fuel ratio learning control to be executed to a satisfactory extent during manufacture in a factory to thereby stabilize exhaust gases and driving performance. The apparatus is provided with a controller which sets air-fuel ratio learning execution counters in a plurality of learning zones. The counters judge whether an air-fuel ratio learning has been executed in an air-fuel ratio learning value storage map based on engine revolutions and engine load, and execute a forced learning control with the amount of purge as a fixed value where the air-fuel ratio learning is not performed at least a preset number of times in all the learning zones with the air-fuel ratio learning execution counters set therein.

Abstract: An air-fuel ratio controller for an internal combustion engine, which controller is capable of: properly correcting an air-fuel ratio after a start-up explosion; preventing inconveniences such as occurrence of an engine stall, a decrease in an engine rotational speed, and a discharge of exhaust gases containing harmful components; and, allocating an idle time-learning value with reference to a rotational engine speed that is obtained at the time of engine start-up, thereby enhancing convenience of use.

Abstract: A failure diagnosis controller of a pressure sensor whereby abnormalities of the pressure sensor can precisely be diagnosed, wrong abnormality diagnoses can be avoided, users' perplexity and confusion on maintenance avoided, users' distrust removed, and unnecessary maintenance eliminated. The invention provides a control means which diagnoses the pressure sensor to be in a failure mode when the intake air temperature is in a state of being measured and the integrated load of the internal combustion engine from its starting time exceeds the criterion of the integrated load.

Abstract: A catalyst deterioration-detecting device is provided with a control which includes a catalyst deterioration-determining section.

Abstract: A misfire-determining controller comprises a control which is provided with the added function of controlling so as to cease misfire monitoring when at least one misfire detection-ceasing conditions is true, which misfire detection-ceasing conditions including: ignition timing being under adjustment; throttle-bypassing air being under adjustment; an ISC valve flow rate being under adjustment; a fuel feedback correction amount being under adjustment; an abnormality being present in a fuel system; and a fuel failure.

Abstract: A catalyst deterioration-determining device for an internal combustion engine having first and second exhaust sensors positioned in an exhaust path of the internal combustion engine upstream downstream, respectively, of a catalyzer located in the exhaust path. The internal combustion engine further including a control station for effecting feedback control to match an air-fuel ratio with a desired value in accordance with first and second detection signals from the first and second exhaust sensors, respectively. The catalyst deterioration-determining device including a determining section provided in the control station which obtains a deterioration-determined value from calculations based on a rich determination delay time, a lean determination delay time, a lean response delay time and a rich response delay time when a deteriorated state of the catalyzer is determined.

Abstract: An air-fuel ratio control system for an internal combustion engine in which an exhaust sensor is located in an exhaust path of the internal combustion engine. A control means provides feedback control to match an air-fuel ratio with a target value in accordance with a detection signal from the exhaust sensor. The control means is provided with a correction section which, upon fulfillment of predetermined implementation conditions of correction determination, detects a response time that elapses from the occurrence of a change in an operating state of the internal combustion engine until the detection signal from the exhaust sensor issues a determination signal value. The correction section governing the feedback control of the air-fuel ratio corrects the feedback control in accordance with the detected response time.

Abstract: A catalyst deterioration judging apparatus for an internal combustion engine wherein first and second exhaust sensors are provided on the exhaust passage respectively upstream and downstream of a catalyst material provided in the exhaust passage. A control arrangement determines deterioration of the catalyst by sensing the exhaust gas upstream and downstream of the catalyst, and provides a feedback control for controlling the air-fuel ratio.

Abstract: An air-fuel ratio control device for an internal combustion engine, in which a first exhaust sensor is disposed at an exhaust passage of an internal combustion engine on an upstream side of a catalytic member which is disposed at the exhaust passage, and a second exhaust sensor is disposed at the exhaust passage on a downstream side of the catalytic member, with the air-fuel ratio being feedback-controlled by a control system in accordance with detection signals from the front and rear exhaust sensors.

Abstract: An apparatus for detecting a flameout in an internal combustion engine includes a rotational speed sensor for detecting engine rotational speed and for generating an electrical signal corresponding to the engine rotational speed. A sensor is provided for detecting the air-fuel ratio of the engine exhaust gas and for generating an output electrical signal corresponding to the air-fuel ratio. An engine load sensor arrangement detects a load state of the internal combustion engine and generates an output electrical signal corresponding to the load state. A control arrangement is provided for comparing the output signal from the exhaust gas sensor with the output signal from the engine load sensor arrangement when the exhaust gas sensor indicates a lean mixture. The control arrangement uses this comparison information to determine whether a flameout has occurred. The control arrangement is also capable of accommodating a response or delay time associated with the exhaust gas sensor.

Abstract: A method and apparatus for controlling the air intake rate of an internal combustion engine, which internal combustion engine includes a deceleration control system responsive to actuation of an idle switch during deceleration for bypassing an intake throttle valve and feeding bypass air into the engine. The control device actuates the deceleration control system only when (1) the cooling water temperature of the engine is greater than or equal to a predetermined water temperature, (2) the engine is decelerating, (3) the engine speed is less than or equal to an actuation speed associated with the deceleration control system, and (4) the engine speed is changing at a rate which is greater than or equal to an actuation differential change rate associated with the deceleration control system.

Abstract: An apparatus controls the number of idle rotations of an internal combustion engine for a vehicle so that the number of engine revolutions becomes a target number of idle rotations, the apparatus starting the controlling of the number of idle rotations when each and every one of a plurality of first conditions is satisfied, the first conditions including the opening degree of an air inlet throttle valve of the internal combustion engine, the vehicle speed, and the number of engine revolutions.