Abstract: A boosting circuit in which a boosting efficiency is enhanced without increasing a chip area, and a time required for reaching a desired boosting voltage different in a voltage level and current ability is shortened. A stage-number switching circuit (20), for switching a connection state between charge pump circuits (12, 13), enables clock signals (CLK1, CLK3) to be supplied to the charge pump circuit (11) among 4-phase clock signals (CLK1 to CLK4) to be supplied to 2-stage charge pump circuits in the case where a stage-number switching control signal (SWHON) is at a supply voltage VDD level, is synchronized with pumping of the charge pump circuits, and turns on an internal switching transistor at a potential higher than a boosting potential of the charge pump circuit (12) in the previous stage, whereby between the 2-stage charge pump circuits (11, 12; 13, 14), a series connection is obtained.

Abstract: There is provided a boosting circuit in which a boosting efficiency is enhanced without increasing a chip area, and a time required for reaching a desired boosting voltage different in a voltage level and current ability is shortened.

Abstract: A malfunction detection apparatus for detecting a malfunction in an evaporated fuel purge system in which fuel vapor from a fuel tank is adsorbed in an adsorbent in a canister and the adsorbed fuel vapor in the adsorbent is purged into an intake passage of an engine. The apparatus includes a detection part for detecting a concentration of fuel in the fuel vapor purged into the intake passage so that a change in the detected fuel concentration from a time when a purge cutting is performed to a time when a purging is performed after the purge cutting has been performed is detected, and a discrimination part for determining whether there is a malfunction in the system on the basis of the change in the detected fuel concentration by the detection part.

Abstract: A device for determining a malfunction of an engine cylinder of an internal combustion engine, comprising a first detection unit for detecting a first engine speed at a predetermined first crank angle, and a detecting second engine speed at a predetermined second crank angle, during a power stroke of two engine cylinders under a continuous combustion cycle, a difference calculating unit for calculating a difference between the first and second engine speeds, a misfire determining unit for determining that a misfire has occurred in a corresponding engine cylinder when the difference is outside a predetermined limit, a malfunction determining unit for determining that a malfunction has occurred in the corresponding engine cylinders when a frequency at which the misfire determining unit determines that a misfire has occurred is larger than a predetermined frequency, a second detection unit for detecting a current engine load, and a first changing unit for changing at least one of the predetermined limit and the

Abstract: A malfunction detecting apparatus for an evaporated fuel purge system includes a first control valve for controlling a flow of fuel vapor in a purge passage between a canister and an intake passage, a second control valve for controlling a flow of air from the atmosphere to the canister via an air inlet opening of the canister, a first control part for turning OFF the second control valve and for turning ON the first control valve during a first time period, so as to subject the purge passage, the canister, and a vapor passage to a negative pressure of the intake passage during the first time period, and a first discriminator for detecting whether or not a malfunction has occurred in the system, in accordance with a pressure change rate derived from pressures of the system sensed at a start of the first time period and at an end thereof.

Abstract: The device for determining a misfiring of a cylinder of a multicylinder engine determines that a misfire has occurred when a change in the angular velocity of the crank shaft detected by a crank angle sensor mounted to the engine body becomes larger than a predetermined set value, and to prevent a misjudgement caused by engine vibration, the device changes the mode of operation for determining the misfire when the engine is operated in a region in which the engine vibration is increased, i.e., in this operating region, the determination of the misfire is not carried out, or the above predetermined set value for the change in angular velocity is increased.

Abstract: A diagnostic device for an exhaust gas recirculation device comprising an exhaust gas recirculation control valve. When the temperature of the engine cooling water exceeds a predetermined temperature, vacuum acts on the vacuum chamber of the exhaust gas recirculation control valve and the supply of the exhaust gas recirculation gas is started. A temperature sensor is arranged in the exhaust gas recirculation passage. When the temperature of the engine cooling water is slightly lower than the predetermined temperature, if the temperature of the interior of the exhaust gas recirculation passage exceeds a predetermined temperature, it is determined that the exhaust gas recirculation control device has malfunctioned.

Abstract: A malfunction detection apparatus for detecting a malfunction in an evaporated fuel purge system in which fuel vapor from a fuel tank is adsorbed in an adsorbent in a canister and the adsorbed fuel vapor in the adsorbent is purged into an intake passage of an engine. The apparatus includes a detection part for detecting a concentration of fuel in the fuel vapor purged into the intake passage so that a change in the detected fuel concentration from a time when a purge cutting is performed to a time when a purging is performed after the purge cutting has been performed is detected, and a discrimination part for determining whether there is a malfunction in the system on the basis of the change in the detected fuel concentration by the detection part.

Abstract: A determining device for determining a failure in an engine cylinder of an internal combustion engine, comprising a variation detecting unit for sequentially detecting a variation in an engine speed between a first engine speed detected by an engine speed detecting unit during a combustion process at a first engine cylinder and a second engine speed detected by the engine speed detecting unit during a combustion process at a second engine cylinder immediately preceding the first engine cylinder with respect to an ignition sequence of all of the engine cylinders, a first determining unit for determining that a misfire has occurred when the variation in the engine speed detected by the variation detecting unit is larger than a predetermined first variation in the engine speed, a second determining unit for determining that a failure has occurred in an engine cylinder when a frequency at which the first determining unit determines that a misfire has occurred is larger than a predetermined frequency, and a value

Abstract: In a double air-fuel ratio sensor system having three-way catalysts, a full O.sub.2 storage amount of the three-way catalysts is estimated and compared with a predetermined amount. When the estimated full O.sub.2 storage amount is smaller than the predetermined amount, the three-way catalysts are determined to have deteriorated.

Abstract: A PCV system with a check valve device oriented in a vertical direction and including a valve body, a seat member, and a stopper plate. The valve body includes a valve head constructed of elastomer. The seat member includes a valve seat surface on a lower surface thereof. The seat member further includes at least one perforation which opens into the lower surface. The valve head of the valve body is disposed below the valve seat surface so as to resiliently contact the valve seat surface when no differential pressure acts on the valve. A stopper plate is disposed between the lower surface of the seat member and the valve head of the valve body. The stopper plate prevents the valve head from being excessively deformed into the perforation to cause cracks to develop in the valve head. As a result, the durability of the check valve device is improved.

Abstract: An idling speed control device normally controlling the idling speed of the engine so that it becomes equal to a desired idling speed. At the time of acceleration, the lean time and the rich time of the air-fuel mixture are calculated during the lean-rich discriminating time, which is basically equal to a time of an occurrence of the lean time and the rich time when the air-fuel ratio is maintained at the stoichiometric air-fuel ratio at the time of acceleration. If the lean time becomes considerably longer than the rich time when the engine is started, the idling speed is increased.

Abstract: A fuel injection control device in which the amount of fuel injected by the fuel injector is increased at the time of acceleration. Namely, at the time of acceleration, the lean time and the rich time of the air-fuel mixture are calculated during the lean-rich discriminating time, which is basically equal to a time of an occurence of the lean time and the rich time when the air-fuel ratio is maintained at the stoichiometric air-fuel ratio at the time of acceleration. When the lean time becomes considerably longer than the rich time, the amount of fuel injected by the fuel injector is further increased.

Abstract: A fuel injection control device in which the supply of fuel into the engine cylinder is stopped at the time of deceleration, and a rich time of the air-fuel mixture is calculated when the supply of fuel is stopped. If the rich time becomes relatively long, the accelerating increasing rate of the amount of fuel is increased, and if the rich time becomes relatively short, the accelerating increasing rate of the amount of fuel is reduced.

Abstract: A fuel injection control device in which it is determined whether the air-fuel mixture is lean or rich at a predetermined crankangle during a lean-rich discriminating time at the time of acceleration. The lean-rich discriminating time is shortened as the degree of the acceleration becomes larger, and the times of being lean and the times of being rich within the lean-rich discriminating time are calculated. When the times of being lean are larger than the times of being rich, and the difference therebetween is larger than a predetermined value, the accelerating increasing rate of the amount of fuel fed into the engine cylinder is increased.

Abstract: A device for detecting a malfunction of a fuel evaporative purge system comprises a pressure sensor for detecting gas pressure in a purge passage connecting a canister to an intake pipe, and an intake vacuum sensor for detecting a negative pressure in the intake pipe. In the purging condition, the device determines whether the obtained relationship between the detected negative pressure in the purge passage and the detected intake vacuum is within a predetermined area and judges that a malfunction has occurred in the system when the relationship is not within the predetermined area.

Abstract: An irregular combustion determining device comprising a variation detecting unit, a first determining unit, and a second determining unit. The variation detecting unit detects a variation in an engine speed on the basis of two successive engine speed detected at predetermined crank angles. The first determining unit determines that an irregular combustion has occurred when the variation in the engine speed detected by the variation detecting unit is larger than a predetermined first variation in the engine speed. When the first determining unit determines that an irregular combustion has occurred, at the next detection of the variation in the engine speed by the variation detecting unit, the second determining unit determines that an irregular combustion has occurred when the variation in the engine speed detected by the variation detecting unit is larger than the predetermined second variation in the engine speed which is smaller than the predetermined first variation in the engine speed.

Abstract: A fuel injection control device for controlling a synchronous injection time period and an asynchronous injection time period. When the synchronous injection time period calculated from the operating state of the engine exceeds one time period of the synchronous injection, the actual synchronous injection time period is restricted so that it does not exceed one time period of the synchronous injection. When the request for the asynchronous injection occurs during the time the synchronous injection is carried out, the actual synchronous injection time period is prolonged by the asynchronous injection time period.

Abstract: A shift indication apparatus having an engine rotation sensor, a throttle valve sensor, and a shift position sensor, a microcomputer having a ROM and RAM for storing data corresponding to the engine speed, throttle valve openings, and the shift positions therein, and an indicator for indicating preferable shift positions to be performed by a driver in which a torque data map and a fuel consumption rate data map have stored in the ROM for calculating various torque and fuel consumption rates so as to obtain preferable shift positions relating to optimum fuel consumption rate in accordance with said data detected. With this construction, it becomes possible for a driver to run his car in accordance with the indications of the shift operation on the indicator so as to enable the economical running of the car to be realized.