Abstract: A control system for an internal combustion engine for an automotive vehicle increases the output torque of the engine during an upshift of the automatic transmission so as to reduce a shock generated during the upshift. Time periods are measured over which respective speed clutches of the automatic transmission have been disengaged. The timing of increasing the output torque of the engine during the upshift of the automatic transmission is changed, based on one of the time periods measured over which one of the speed clutches of the automatic transmission to be selected for the upshift has been disengaged.

Abstract: A control system for an automatic transmission of an internal combustion engine installed on an automotive vehicle measures a duration over which the automatic transmission continues to be in a speed position. Downshift of the speed position of the transmission to a lower speed position is inhibited if the measured duration does not exceed a predetermined time period, when it is determined that the automotive vehicle is in a predetermined decelerating condition.

Abstract: In a control system for controlling motor vehicles in such a manner that the drive force of the vehicle is determined by the accelerator pedal stroke and the vehicle speed, the fuel consumption is minimized by appropriately selecting the gear ratio of the power transmission system under each current operating condition. In particular, the present invention accounts for the slip ratio of the lock-up clutch as well as the transmission efficiency of the torque converter by noting the fact that the lock-up clutch operates under semi-tight conditions as well as under tight and loose conditions.

Abstract: A driving force-calculating system calculates a desired driving force required by an automotive vehicle depending on operating conditions of the vehicle. A kinetic energy parameter representative of kinetic energy of the vehicle is calculated from an amount of change in speed of the vehicle assumed during acceleration of the vehicle. A correction coefficient is calculated based on an average value of a maximal value of the kinetic energy parameter assumed within a predetermined time period. The desired driving force required by the vehicle is calculated by the use of the correction coefficient. A control system for automotive vehicles which incorporates the driving force-calculating system is also provided.

Abstract: A device for detecting abnormality of the fuel supply system of an internal combustion engine inhibits supply of evaporative fuel to the intake passage when the air-fuel ratio correction coefficient becomes smaller than a predetermined value, and thereafter determines that the fuel supply system is normal when the air-fuel ratio correction coefficient increases above the predetermined value as a result of the inhibition of the supply of the evaporative fuel. The supply of the evaporative fuel to the intake passage is resumed after the determination that the fuel supply system is normal has been made. Determination of abnormality of the fuel supply system is inhibited after resuming of the supply of the evaporative fuel until the engine enters a predetermined operating condition in which the air-fuel ratio correction coefficient has increased.

Abstract: An evaporative fuel-processing system for an internal combustion engine, comprises an evaporative emission control system in which a first control valve is arranged across an evaporative fuel-guiding passage extending between a fuel tank and a canister, a second control valve across a purging passage extending between the canister and the intake system of the engine, and a third control valve at an air inlet port of the canister, respectively. An external diagnostic device is humanly operatable for diagnosing operating conditions of the engine and the vehicle.

Abstract: An evaporative fuel-processing system for an internal combustion engine, incorporates an evaporative emission control system in which a first control valve is arranged across an evaporative fuel-guiding passage extending between a fuel tank and a canister, a second control valve across a purging passage extending between the canister and the intake system of the engine, and a third control valve at an air inlet port of the canister, respectively. An ECU generates operation command signals to the first to third control valves for closing or opening the same to bring the evaporative emission control system into a predetermined negatively pressurized state. The ECU is responsive to an output from a parameter sensor which detects at least one of vehicle speed, temperature within the fuel tank, and an amount of fuel within the fuel tank, for determining whether there is an abnormality in the evaporative emission control system, based upon an output from a tank internal pressure sensor.

Abstract: A method of detecting abnormality in an evaporative fuel-purging system (evaporative emission control system) for an internal combustion engine comprises the steps of: (1) determining whether or not the engine is in a predetermined operating condition after completion of warming-up of the engine, (2) temporarily inhibiting purging of evaporative fuel into an intake passage when it is determined that the engine is in the predetermined operating condition, (3) obtaining a first value based on a parameter reflecting an amount of evaporative fuel purged into the intake passage during the temporary inhibition of the purging of the evaporative fuel, (4) obtaining a second value based on the parameter during execution of the purging of the evaporative fuel carried out after the temporary inhibition of the purging of the evaporative fuel, (5) comparing the first value with the second value, and (6) determining whether or not there is abnormality in the evaporative fuel-purging system, based on a result of the compari

Abstract: A fail-safe device for an engine temperature sensor. A value of the engine temperature detected by the engine temperature sensor is renewed and stored for engine control. While the engine is detected to be in a low temperature region lower than a predetermined value on the basis of the detected value, renewal of the detected value is inhibited when it has decreased. It is determined that the detected value has decreased, when the detected value is lower than a lower limit value. The lower limit value is set to a value corresponding to the detected value when the engine is detected to be in the low temperature region, whereas it is set to the predetermined value when the engine is detected not to be in the low temperature region. Renewal of the detected value is inhibited when the detected value has not remained within a predetermined range over a predetermined time period.

Abstract: A method of detecting failure of an exhaust gas component concentration sensor for detecting concentration of a component of exhaust gases from an internal combustion engine. The method comprises the steps of: (1) applying a predetermined voltage to the sensor, (2) determining whether or not a change in an output voltage from the sensor caused by the application of the predetermined voltage to the sensor is smaller than a predetermined value, and (3) deciding that the sensor is faulty when the change in the output voltage is smaller than the predetermined value. A device for sensing concentration of a component of exhaust gases from an internal combustion engine comprising an electric resistance member connected in series between an electric current supply source and one of a pair of electrodes provided on a solid electrolytic element.

Abstract: A method of controlling in a feedback manner the air-fuel ratio of an air-fuel mixture being supplied to an internal combustion engine of the type that vaporized fuel is supplied from a fuel supply system to an intake system thereof. The air-fuel ratio is controlled by the use of a correction value which varies in response to an output from an exhaust gas ingredient sensor, and the maximum or minimum value of which is limited to an upper or lower limit value. The pressure of the vaporized fuel in the fuel supply system is sensed, and at least one of the upper and lower limit values is set in accordance with the sensed pressure of the vaporized fuel. Further, the air-fuel ratio is controlled by the use of an average value of the correction value. The pressure of the vaporized fuel in the fuel supply system is sensed, and the calculation of the average value is inhibited when the sensed pressure of the vaporized fuel is higher than a predetermined value.

Abstract: A fuel supply control method for a multicylinder internal combustion engine equipped with a fuel supply control system including a main fuel injection valve disposed in the intake passage upstream of the throttle valve, and an auxiliary fuel injection valve disposed in the intake passage downstream of the throttle valve and upstream of the intake manifold, for controlling the fuel supply control system according to operating conditions of the engine.

Abstract: A fuel supply control method for a multicylinder internal combustion engine equipped with a fuel supply control system including a main fuel injection valve disposed in the intake passage upstream of the throttle valve, and an auxiliary fuel injection valve disposed in the intake passage donwstream of the throttle valve and upstream of the intake manifold, for controlling the fuel supply control system according to operating conditions of the engine.

Abstract: A method of controlling fuel supply during beginning acceleration and acceleration after the interruption of fuel supply of an internal combustion engine is provided wherein a basic fuel supply amount which is determined in accordance with stable operating conditions of the engine is increased when it is detected that the throttle valve of the engine is opened from its almost closed position. The method comprises the steps of determining a reference value by adding a predetermined value of the throttle valve opening to a detected amount or value of throttle valve opening when it is detected that the throttle valve is opened from its almost closed position. The basic fuel supply amount is additionally correctionally increased if the correctional increase of the basic fuel supply amount, which was initiated upon detection of opening of the throttle valve, has not yet reached an end when the detected value of the opening of the throttle valve reaches the throttle valve opening reference value.

Abstract: An ignition timing control method for an internal combustion engine, which controls the ignition timing, on the basis of a basic ignition timing value determined as a function of operating parameters of the engine. When a detected parameter value indicative of engine temperature is lower than a predetermined value, a correction variable for the basic ignition timing value is determined based upon detected parameter values indicative of engine temperature and engine load magnitude, to correct the basic ignition timing value thereby. Ignition of the mixture is effected at a timing according to the corrected basic ignition timing value. Preferably, when detected engine rotational speed is lower than a predetermined value lower than the engine idling speed or when it is higher than a predetermined high rotational speed value, the correction of the basic ignition timing value by the correction variable is prohibited.

Abstract: A solenoid operated cut valve controls flow through a vent passage leading from a float chamber for a carburetor for an internal combustion engine. A normally closed switch opens in response to high temperature of the engine, and a normally closed timer switch opens at the start of cranking and closes again after a predetermined time of cranking. The switches are connected to the solenoid to prevent increase in pressure within the float chamber from delivering an excessive amount of fuel to the air intake passage of the engine. In a modification, a switch responsive to vacuum intensity in the intake passage is included in the solenoid circuit to facilitate acceleration of the engine after a hot start.