Abstract: In an internal combustion engine equipped with an electronic throttle control device for electrically driving a throttle valve, a control apparatus includes failure detecting means for detecting a failure of the electronic throttle control device, and control means for limiting fuel supply to the engine when the failure detecting means detects a failure of the electronic throttle control device, if the rotating speed of the engine becomes equal to or higher than a predetermined value.

Abstract: A control apparatus for an internal combustion engine is applied to vehicles equipped with a so-called drive by wire. When one of several control systems within the control apparatus fails, the drive is urged to obtain repairs. Also, even when all of the several control systems of the drive by wire fail and the failures of these control systems cannot be detected, unpredictable motion of the throttle valve can be prevented, thereby enhancing vehicle safety.

Abstract: A throttle valve control device is provided which includes a throttle valve mounted in an intake pipe of an internal combustion engine, an actuator which drives the throttle valve so as to change an opening of the throttle valve, an operating condition sensor which detects operating conditions of the internal combustion engine, an accelerator sensor which detects an accelerator pedal position that represents an amount by which an accelerator pedal is depressed by a driver, and a control unit for controlling the throttle valve.

Abstract: The present invention relates to a control apparatus for a vehicle equipped with an electronic throttle control unit (drive by wire) as electronic throttle control means and an automatic transmission, and the object of the invention is to provide a control apparatus for a vehicle which is capable of ensuring stable travel even in the case where a throttle valve is stuck by a failure of an electronic throttle control unit. In a control apparatus for a vehicle equipped with electronic throttle control means for electrically driving a throttle valve by drive means and an automatic transmission having a plurality of speed change gear stages, the control apparatus is provided with sticking judgment means for judging whether or not the throttle valve has been stuck, and speed change regulation means for inhibiting use of a predetermined gear stage among the speed change gear stages of the automatic transmission in the case where the throttle valve is judged to have been stuck by the sticking judgment means.

Abstract: A suction control device for a multiple cylinder internal combustion engine comprising a shell body presenting a suction path communication to each cylinder in a multiple cylinder internal combustion engine, a rotary shaft (21a) penetrating and born by the shell body, a butterfly valve (21) supported by the rotary shaft and provided in each of the suction paths so that it can freely open or close the suction path, and a restricting means for restricting movement of the rotary shaft in the axial direction; wherein the rotary shaft and the butterfly valve are monolithically formed with a resin material, the shell body is made from a resin material, and the restricting means comprises an expanding piece (21b) monolithically formed on the rotary shaft and having a width in the radial direction thereof, a contact wall (24) formed on the shell body and slidably contacting and supporting the expanding piece, and a resilient energizing member (33) for energizing the expanding piece to contact it to the contact wall.

Abstract: A method for detecting a misfire by fluctuation in crankshaft rotation in which the occurrence of a misfire can be detected exactly by eliminating the effect of detection error in detecting the fluctuation in crankshaft rotation, caused by the error in the construction of a crank angle sensor. By succeedingly receiving pulses from the crank angle sensor, a processor detects a time interval taken from the entering into a crankshaft rotation angle region, relating to a cylinder corresponding to both pulses, to the leaving therefrom (S2), calculates the crankshaft angular acceleration D.omega..sub.n by using the correction factor calculated on the basis of the above detected time interval, and the time interval determined by dividing the time taken for one rotation of the crankshaft by the number of cylinders (S3, S4), the latter interval being free from sensor error, and detects the occurrence of a misfire when the calculated value D.omega..sub.n is less than the decision value (S5 through S7).

Abstract: A fault diagnosis apparatus for a fuel evaporative emission suppressing system has an electronic control unit which inputs an average value of integral terms for air-fuel ratio feedback control, engine speed, etc. when diagnosis executing conditions are satisfied, and then starts opening operation of a purge control valve. Subsequently, the average value of integral terms, engine speed, etc. are input again. If no substantial change occurs in the average value, etc. with driving of the purge control valve, it is concluded that purge air for fault diagnosis has not been introduced, and that the suppressing system is faulty. In driving the purge control valve, its driving duty ratio is increased by a relatively small increment till the driving duty ratio reaches a predetermined duty ratio.

Abstract: A method and apparatus for detecting faults in a fuel evaporative emission control system, in which the fuel evaporative emission which is admitted from a fuel tank and adsorbed once by a canister is separated from the canister by purge air and sucked into a suction passage of an engine. The fault diagnostic apparatus fluid-tightly closes the fuel tank such that a vacuum is held in the fuel tank, and then detect the presence of a leak in a fuel evaporative emission flow path on the basis of a rate of increase of the pressure in the fuel tank. At the same time, the average value of the pressure in the fuel tank is calculated at regular intervals, and the calculated average value is compared with levels of the pressure in the tank detected within a predetermined period of time, so that the detection of the leak is interrupted depending upon the result of the comparison.

Abstract: A detecting apparatus for a catalytic converter has a pair of O.sub.2 sensors, arranged individually on the up- and downstream sides of the converter, and an electronic control unit for discriminating reduction of the purifying capacity of a three-way catalyst in the converter. This unit discriminates the reduction of the purifying capacity in accordance with the comparison between a decision value and the ratio between the respective frequencies of outputs from the O.sub.2 sensors. In the case where the O.sub.2 sensor on the upstream side is subject to thermal degradation, its decision value is corrected, or the decision itself is interrupted.

Abstract: A deterioration diagnostic apparatus for a three-way catalyst includes an electronic control unit, which obtains a frequency of reversals of the changing direction in which the output of an upstream-side O.sub.2 sensor changes, based on the number of times the output voltage of the O.sub.2 sensor crosses a threshold. Also, the control unit obtains a frequency of reversals of the changing direction in which the output of a downstream-side O.sub.2 sensor changes, based on the number of times the output voltage of the downstream-side O.sub.2 sensor crosses upper and lower reversal reference values which are obtained by adding and subtracting a hysteresis constant to and from an average value of input values of the downstream-side O.sub.2 sensor output voltage.

Abstract: A system for the diagnosis of an idling speed control system has a first timer for measuring the time elapsed since entrance to a feedback control mode, an engine speed state detection unit for detecting whether the engine speed has fallen within a predetermined speed range, a second timer for measuring the time elapsed since the engine speed has been detected to fall within the speed range, and a normality determining unit for determining that the idling speed control system is in order, when the time measured by the first timer is within a first preset time and also the engine speed is detected to have fallen within the speed range and has remained in the speed range until the time measured by said second timer reaches a second preset time.

Abstract: A fault diagnosis apparatus for detecting a fault in a fuel evaporative emission suppressing system, if it is concluded that an engine (1) is being operated in an operating state fulfilling fault diagnosis execution conditions, detects the current valve opening position of an idling speed control (ISC) valve (8) and then drives a purge control valve (46) to open the same. If a relatively high load is applied to the engine at this time, the threshold value determining the operating sensitivity of the ISC valve is so corrected as to be decreased. When a predetermined period of time has elapsed from the moment when the valve opening position of the ISC valve is detected, the valve opening position of the ISC valve is detected again. If the deviation between these valve opening positions is not larger than the threshold value, it is concluded that the purge air introduction by the drive of the purge control valve is not performed, that is, it is concluded that the valve is faulty.

Abstract: A fault diagnosis apparatus for detecting a fault in a fuel evaporative emission suppressing system comprises an electronic control unit. When fault diagnosis execution conditions are fulfilled, the electronic control unit stores an average of integral term values for air-fuel ratio feedback control, operating position of an idling speed control valve, and engine speed, and then actuates a purge control valve of the suppressing system so that the valve opens. In a predetermined time period after the actuation of the purge control valve, the integral term average and the like are stored again. If any changes of the integral term average and other values caused by the actuation of the purge control valve are detected, the suppressing system is concluded to be normal. If no changes are detected, on the other hand, the suppressing system is concluded to be faulty.

Abstract: An apparatus for determining a failure of an exhaust gas recirculation (EGR) apparatus includes an electronic control unit. When judging the fulfillment of the failure diagnosis executing condition, the electronic control unit stores the intake pressure detected by a pressure sensor, and then introduces part of the exhaust gas from an engine to an intake passage via an EGR passage to start the EGR for failure diagnosis. Thereafter, the intake pressure is detected again. If a significant change in intake pressure does not occur before and after the execution of the EGR for failure diagnosis, it is judged that the EGR apparatus is faulty.

Abstract: A misfire detection method is provided, which method makes it possible to accurately detect the occurrence/absence of misfire by eliminating a detection error in misfire detection. This error is caused by a vibrational increase or decrease of the rotational changing rate of a crankshaft after a misfire state occurs. A processor, which receives pulse outputs from a crank angle sensor, calculates in sequence angular accelerations D.omega..sub.n-2, D.omega..sub.n-1, D.omega..sub.n, and D.omega..sub.n+1 in crank angle areas which correspond to a preceding cylinder, two cylinders checked for misfire, and a succeeding cylinder, respectively. If the values D.omega..sub.n-1 and D.omega..sub.n n significantly decrease in comparison with the values D.omega..sub.n-2 and D.omega..sub.n-1, respectively, then it is tentatively determined that misfire has occurred in both cylinders checked. Then If the value D.omega..sub.n+1 significantly increases compared to the value D.omega..sub.

Abstract: A fault detection system is provided for an exhaust gas recirculation (EGR) system. The fault detection system is constructed of an engine operation state detection device, an EGR valve opening/closing device, and a system operation fault detection device. The engine operation state detection device is provided with an air flow sensor arranged in an intake passage on an upstream side of a throttle valve, and detects the engine operation state that the pressure difference between a pressure within an intake passage on a downstream side of the throttle valve and a pressure within the intake passage on an upstream side of the throttle valve is not greater than a critical pressure. Upon detection of the above engine operation state, the EGR valve opening/closing device opens or closes an EGR valve.

Abstract: An exhaust gas cleaning device for controlling the air-to-fuel ratio of the air-fuel mixture supplied to an internal combustion engine (1) provided with a catalytic converter (14) disposed in the exhaust pipe (13). The air-to-fuel ratio is oscillated around the central level of the integral control or proportional plus integral feedback control signal based on the output of an air-to-fuel ratio sensor (12); the amplitude of oscillation and the proportional control amount are, or alternatively, the frequency of the oscillation is, varied in accordance with the operating condition of the engine.

Abstract: An exhaust gas cleaning device for controlling the air-to-fuel ratio of the air-fuel mixture supplied to an internal combustion engine (1) provided with a catalytic converter (14) disposed in the exhaust pipe (13) is disclosed. The air-to-fuel ratio is oscillated around the central level of the integral control or proportional plus integral feedback control signal based on the output of an air-to-fuel ratio sensor (12); the amplitude of oscillation and the proportional control amount are, or alternatively, the frequency of the oscillation is, varied in accordance with the operating condition of the engine.