Abstract: A variable valve-timing engine includes a VTC for adjusting a relative phase angle of an exhaust cam for opening and closing an exhaust valve and an intake cam for opening and closing an intake valve; an oil pressure controlling unit for operating the VTC; a deterioration detecting unit for detecting the deterioration of hydraulic fluid in the oil pressure controlling unit; a correcting unit for correcting the oil pressure of hydraulic fluid of the oil pressure controlling unit based on a detected value by the deterioration detection unit, and a deterioration indicating unit for indicating a replacement of the hydraulic fluid based on the detected value of the deterioration detecting unit, so that the user can be advised of a required oil replacement.

Abstract: A lead frame material comprises a base plate consisting of copper or copper alloys, and a protective coating formed on the upper or the both surface of the base plate. The protective coating is composed of at least one metal selected from the group consisting of gold, gold alloy, silver, silver alloy, palladium and palladium alloy, and has a thickness of 10-500 angstrom. The protective coating is formed by means of vapor deposition. It is possible to form an intermediate coating of nickel or nickel alloys between the surface of the base plate and the protective coating, by means of vapor deposition or wet plating. The suitable thickness of the intermediate coating is within the range of 50-20000 angstrom.

Abstract: In a control system for a valve actuation property variable control device which can switch over between a plurality of modes including a low speed mode for adapting at least one of an intake valve and an exhaust valve of an engine to a low speed range and a high speed mode for adapting the valve to a high speed range at least according to the rotational speed of the engine and a representative temperature of the engine, to prevent an abrupt change in the engine output by switching over valve actuating properties while the engine is being warmed up, the load condition of the engine is detected so that the transition from the low speed mode to the high speed mode may be prohibited if the representative temperature of the engine exceeds a prescribed level while a load higher than a prescribed level is being detected. Thereby, the driveability of the engine is improved.

Abstract: An ignition timing control system for an internal combustion engine in which an ECU sets a basic spark advance value in response to operating condition of the engine, corrects the set basic spark advance value, and delimits the corrected spark advance value in a spark retarding direction by means of a retard limiting value. The ECU further detects operation of a slip control system which detects a predetermined slip state of driving wheels of the vehicle and controls the engine so as to reduce output thereof upon detection of the predetermined slip state. When the slip control system is operative, the ECU changes the retard limiting value toward an advanced side relative to a value set when the slip control system is inoperative.

Abstract: An air-fuel ratio control method for an internal combustion engine. The air-fuel ratio of an air-fuel mixture supplied to the engine is feedback-controlled to a predetermined value in response to an output from the exhaust gas ingredient concentration sensor. The temperature of at least one component part of the engine, which should be controlled, is estimated based on the detected temperature of exhaust gases, engine rotational speed, and engine load. The air-fuel ratio of the air-fuel mixture is inhibited from being feedback-controlled but enriched, when the estimated temperature of any one of the at least one component part of the engine is higher than a corresponding predetermined value.

Abstract: A method of determining the activation of an exhaust gas ingredient-concentration sensor for use in an internal combustion engine. The air-fuel ratio of a mixture is controlled in a feedback manner by the use of a coefficient varying with an output of the sensor during engine operation in an air-fuel ratio feedback control region. The activation of the sensor is determined based on the output of the sensor. When the engine has shifted from the air-fuel ratio feedback control region to a predetermined decelerating region, calculated is an average value of values of the coefficient obtained by the feedback control immediately before the shifting. The air-fuel ratio of the mixture is leaned by the use of the average value thus calculated. It is determined whether or not the sensor is activated when the air-fuel ratio has thus been leaned.

Abstract: A method and device for controlling the air-fuel ratio of an internal combustion engine are disclosed. In this method and device the actuator for controlling the air-flow rate is selected as an actuator capable of causing change with passage of time frequently, and the deviation of air-fuel ratio is detected by an air-fuel sensor from a small air-flow rate point corresponding to, for example, an idling speed of engine and a large air-flow rate point corresponding to a predetermined engine speed during running thereby correcting the parameters a and b.

Abstract: An electronically controlled internal combustion engine provided with an accelerator position sensor wherein, in order to positively prevent violent running and make some degree of running possible, an idling switch, intermediate switch and fully opening switch issuing signals when a wiper crosses them are provided within the accelerator position sensor, in case the magnitude of the output from the accelerator position sensor when any of the above mentioned respective switches issues signal during the operation of the accelerator position sensor is not in a normal range memorized in advance, the accelerator position sensor will be judged to fail and, when the accelerator position sensor is judged to fail, signals from the accelerator position sensor will not be accepted, a desirable running state will be judged on the basis of a combination of the signals from the respective switched and an injector will be controlled.