Abstract: A fuel concentration monitoring unit includes a fuel temperature dependent error correction circuit in the unit. A fuel concentration indicative voltage signal variation rate set with taking a specific fuel concentration as reference point. The output incorporated in the unit.

Abstract: Disclsoed is a system of protecting an engine of the type where a driving power is transmitted through a variable reduction gear ratio belt, in which when breaking of the belt is detected, control of stopping the engine is performed, or control of excessively enriching the air-fuel ratio of an air-fuel mixture supplied to the engine is performed and then, control of stopping the engine is performed.

Abstract: A crankcase temperature sensor is provided for detecting temperature of a crankcase. A low speed basic injection pulse width is provided based on the detected crankcase temperature for low engine speed. An ordinary fuel injection pulse width is provided in accordance with engine operating conditions for ordinary engine operating condition. A comparator is provided for comparing the low speed injection pulse width and the ordinary fuel injection pulse width with each other. A larger injection pulse width is determined for injecting fuel.

Abstract: In the control of the sequential fuel injection in an internal combustion engine, where the engine load is set based on the opening of the throttle valve and the engine revolution number and the quantity of correction of the fuel supply quantity is determined based on the ratio of the change of this engine load and the time up to a predetermined time during the intake stroke, this time is computed for each cylinder and the correction quantity is set individually for the respective cylinders.

Abstract: In a fuel supply control apparatus constructed so that a fuel supply quantity is feedback-controlled to bring a detected value of an air-fuel ratio of an air-fuel mixture sucked in an engine to a target air-fuel ratio, a disorder of air-fuel ratio-detecting means is diagnosed based on a change of the balance of the response characteristic of the air-fuel ratio-detecting means in both the change directions of the air-fuel ratio, a change of an output value of the air-fuel ratio-detecting means or a change of the frequency of the feedback control.

Abstract: An automatic power interrupting system for a vehicular control circuit including a relay switch having a contact connected between a power source and the supply terminal of a control circuit and a relay coil connected with the power source, a control switch connected between the power source and the supply terminal and with the signal input terminal of the control circuit and turned on only by an external force, a revolution detector for detecting engine revolutions and a switching device for turning the relay switch on when power is supplied to the circuit and off after a predetermined time period measured after stop of the engine based on a signal from the revolution detector.

Abstract: The present invention relates to a method and apparatus for detecting deterioration of a hot-wire type sucked air flow quantity-detecting device of an engine, in which the change ratio of the output voltage of the hot-wire type sucked air flow quantity-detecting device is measured when the output voltage of the sucked air flow quantity-detecting device is to be changed while the engine is in the substantially non-revolving state, and deterioration is judged by comparing the measured change ratio with a predetermined value, whereby it is possible to exchange parts promptly just in time and prevent degradation of the exhaust gas-purging performance of a vehicle.

Abstract: An inspection device is provided an inspection parameter generator generating predetermined parameter data. The parameter data is transmitted to a control unit subjecting inspection. The inspection device receives input signal from the control unit, which input signal corresponds to the parameter data input to the control unit. Both of the control unit and inspection device processes the corresponding data. The control unit feeds resultant output to the inspection device. The inspection device compares its own resultant data and the resultant output of the control unit to make judgment whether the control unit operates in normal condition or not.

Abstract: Disclosed is a system for controlling the fuel injection quantity at the start of a two-cycle engine, in which a predetermined amount of a fuel is preliminarily injected when a key switch of the engine is turned on, the revolution speed of the engine is smaller than a reference value and the opening degree of a throttle valve takes a predetermined change pattern.

Abstract: A method for detecting an intake pressure in an internal combustion engine which comprises detecting the intake pressure in the engine and at least one engine driving condition, variably setting a sampling period of the intake pressure to a sampling period, according to the engine driving condition, which is substantially different from a pulsation period of the intake pressure, sampling processing the intake pressure according to the sampling period set to set the value obtained by the sampling processing as a final detected value of the intake pressure, whereby the reliable sampling of the intake pressure is performed even if the intake pressure is pulsated.

Abstract: An assist air supply system employs a pressurized air source which is formed separately from an induction system of an automotive internal combustion engine. The pressurized air source is connected to an induction system in the vicinity of a fuel injection valve so as to inject pressurized air in the vicinity of fuel injected through the fuel injection valve. A valve means is disposed between the pressurized air source and discharge of a pressurized air passage, so that the pressurized air can be injected or discharged in synchronism with injection timing of the fuel injection valve.

Abstract: Disclosed are a method and apparatus for detecting deterioration of a sucked air flow quantity-detecting device of an engine, in which during a predetermined period after the start of use of the engine, detected values of sucked air flow quantities detected by the sucked air flow quantity-detecting device are learned for respective areas of the engine driving state, and then, the detected value of the sucked air flow quantity detected by the air flow quantity-detecting device is compared with the learned value and deterioration of the sucked air flow quantity-detecting device is judged when the difference is larger than a predetermined value.

Abstract: When there is observed a tendency that the proportion of the correction by an air-fuel ratio correction value for the feedback control of an air-fuel ratio in an air-fuel mixture sucked into an engine to a target air-fuel ratio is increased in the air-fuel ratio-enriching direction in a region of a smaller sucked air flow quantity, it is judged that the leakage of air into a suction system of the engine occurs. The quantity of the correction of the sucked air flow quantity corresponding to the quantity of leaking air is set based on the relation between the air-fuel ratio correction value and the corresponding sucked air flow quantity, and the detection value of an air flow meter is corrected based on this correction quantity.

Abstract: In an alcohol sensor failure detection system for an internal combustion engine, a failure of an alcohol sensor is detected utilizing an air/fuel ratio dependent correction coefficient during a FEEDBACK control being executed to maintain an air/fuel ratio of an air/fuel mixture at a target value with a fuel supply amount which is corrected by the correction coefficient. The correction coefficient is variable between predetermined maximum and minimum values depending on a monitored air/fuel ratio of the air/fuel mixture. When the correction coefficient is retained to the maximum or minimum value for no less than a predetermined time, the failure of the alcohol sensor is determined.

Abstract: An oxygen gas concentration-detecting apparatus for use in an internal combustion engine comprising a plate-shaped substrate, a plate-shaped oxygen ion-conducting solid electrode for generating an electromotive force between a first surface contacted with air and a second surface contacted with an exhaust gas of the engine according to the difference between the concentrations of oxygen gases of the air and the exhaust gas, the solid electrode being laminated on the substrate, a pair of electrode members for taking out the electromotive force as a detection signal and a nitrogen oxide-reducing catalyst layer for promoting the reduction of nitrogen oxide arranged to cover the second surface of the oxygen ion-conducting solid electrode. By this apparatus, the concentration of oxygen gas inclusive of oxygen gas generated by reduction of nitrogen oxides can be precisely detected.

Abstract: In a multi-fuel engine which is operated on gasoline, alcohol or a mixture of the two, upon an alcohol sensor being diagnosed as being out of order, an alcohol correction factor in the injection pulse width calculation is clamped at an arbitrary value and in the case of high load operation a carburetion correction factor is incrementally increased instead of being set to a pre-recorded value for the instant load.

Abstract: A fail-detection system is designed for detecting failure of a fuel concentration sensor for monitoring concentration of one of a plurality of different types of fuels which are blended to be supplied to an internal combustion engine, which fuel concentration sensor varies output signal level depending upon the monitored fuel concentration in the blended fuels. The system comprises first means for receiving the output signal from the fuel concentration sensor for providing a monitored data associated with monitored fuel concentration, second means for providing a reference data representative of normal range of the value of the monitored data, and third means for comparing the monitored data with the reference data for detecting abnormality of the fuel concentration sensor when the monitored data is out of a predetermined relationship with the reference data.

Abstract: A method and apparatus for detecting an intake air state quantity in an internal combustion engine, where a detected value of an intake air state quantity participating in the quantity of air sucked in the engine, are dislosed. The method and apparatus are constructed so that a random number is generated, the frequency time of the above-mentioned sampling is variably set based on this random number, and the sampling frequency of the detected value of the intake air state quantity is randomly changed.

Abstract: An oxygen gas concentration-detecting apparatus in an internal combustion engine using an alcohol fuel includes a ceramic substrate having one surface falling in contact with a reference gas and the other surface falling in contact with an exhaust gas of the engine and generating an electromotive force according to oxygen gas concentrations of both the gases. A pair of electrode members are arranged on the ceramic substrate to take out the electromotive force. A first oxidation catalyst layer is formed on the outer surface of the ceramic substrate to promote oxidation reaction of unburnt components. A laminate of a protecting layer of a metal oxide and a reduction catalyst layer of promoting reduction reaction of nitrogen oxides is formed on the outer surface of the first oxidation catalyst layer, and a second oxidation catalyst layer is arranged on the outer side face of the laminate to promote oxidation reaction of hydrogen gas.

Abstract: A fuel supply control system derives a basic induction volume efficiency on the basis of an intake air pressure and modifies the basic induction volume efficiency with a correction value which is derived on the basis of an engine revolution speed and the intake air pressure. An induction volume efficiency is derived on the basis of modified basic induction volume efficiency, which derived induction volume efficiency is used for deriving a basic fuel supply amount with the intake air pressure. The basic fuel supply amount thus derived is used for controlling fuel supply for the engine. Derivation of the basic induction volume efficiency is performed by an interrupt routine which may be executed in a predetermined timing derived depending upon a time or in synchronism with engine revolution cycle. The correction value may be derived in a background job.