Abstract: A system according to the invention controls the vaporized amount of a blended fuel composed of gasoline and an alcohol such as methanol and contained in a fuel tank mounted at a vehicular internal combustion engine. The methanol concentration in the fuel is sensed and from the sensed value, reid vapor pressure of the fuel is presumed. The pressure in the fuel tank is then regulated at a target pressure by adjusting the amount of vaporized fuel to be removed from the fuel tank and fed to a canister in response to the presumed reid vapor pressure.

Abstract: A system for controlling supply of fuel to a hybrid fuel powered engine during starting. The system has a sensor detecting the alcohol concentration of the fuel, a device for calculating an alcohol correction factor from the detected alcohol concentration, a device for correcting a basic amount of fuel supply in accordance with the alcohol correction factor, a device for increasing or decreasing the factor in increments of a magnitude determined on the basis of the engine coolant temperature once per interval determined on the basis of the engine coolant temperature, and a device for reversing the direction of the increments each time the factor reaches an upper limit value or a lower limit value, whereby the factor is swept over a prescribed range until the engine starts.

Abstract: An air-fuel ratio control system for internal combustion engine using fuel containing alcohol corrects an amount of fuel supplied to the engine by a correction amount dependent on load on the engine when the engine is in a predetermined high load region. The concentration of alcohol in the fuel is detected, and the correction amount is decreased to a smaller value as the detected concentration of alcohol in the fuel is higher.

Abstract: A system for controlling an air/fuel ratio of an internal combustion engine supplied with a blended fuel of gasoline and alcohol and equipped with a blowby gas ventilator. An oxygen sensor is provided and an amount of fuel supply is corrected in response to the detected air/fuel ratio within a range having a lower limit set in the lean direction and an upper limit set in the rich direction. At engine starting, injected alcohol may not vaporize but leak into the crankcase and will then vaporize to pass into the air intake passage along with the blowby gas when the engine temperature rises, causing the air/fuel ratio to be become rich beyond the correction lower limit. For that reason, in this system, engine coolant temperature and alcohol content in the fuel are detected. And if the temperature is within a range defined from the alcohol boiling point when the alcohol content is above a reference value, the lower limit of the range is shifted in the leaner direction.

Abstract: An air-fuel ratio control system for an internal combustion engine using an alcohol blended fuel, in which an alcohol concentration-dependent correction coefficient for use in calculating an amount of fuel supplied to the engine is calcuated in response to concentration of alcohol in the fuel defected by an alcohol concentration sensor. An average value of the correction coefficient is calcuated depending on operating conditions of the engine. The amount of fuel supplied to the engine is calculated by the use of the average value of the correction coefficient to thereby control the air-fuel ratio of an air-fuel mixture supplied to the engine.

Abstract: An air-fuel ratio control method controls the air-fuel ratio of an air-fuel mixture supplied to an internal combustion engine having spark plugs, and heaters for heating the air-fuel mixture in the vicinity of respective ones of the heaters, the air-fuel mixture containing a fuel which is poor in atomizing characteristic at a low temperature. The method comprises the steps of (1) determining whether or not a temperature of the engine is lower than a predetermined value, (2) determining whether or not the engine is being cranked, (3) detecting an amount of electric current flowing through each of the heaters, and (4) controlling an amount of fuel supplied to the engine based on the detected amount of electric current when it is determined that the temperature of the engine is lower than the predetermined value and at the same time the engine is being cranked.

Abstract: An abnormal combustion-detecting device and a combustion control device for internal combustion engines. Ignition timing for the cylinders is set in accordance with engine operating conditions. The set ignition timing for at least one of the cylinders is retarded when the engine is in a predetermined operating condition. Abnormal combustion caused by postignition within the at least one cylinder is detected when the set ignition timing is retarded. When abnormal combustion is detected within the at least one cylinder, temperature within the cylinders is lowered, thereby positively preventing possible occurrence of preignition.

Abstract: A fuel-vapor purge and air-fuel ratio control system controls the amount of fuel vapor to be purged under an engine vacuum into a carburetor of an automotive engine from a charcoal canister and also controls the air-fuel ratio of an air-fuel mixture to be supplied to the carburetor. The fuel vapor is purged form the charcoal canister by applying the engine vacuum to the charcoal canister only when the air-fuel ratio is controlled. The applied engine vacuum may be regulated to control the amount of purged fuel vapor to change in proportion to the amount of air drawn by the engine, or the amount of purged fuel vapor may be increased to an upper limit when the air-fuel ratio is in a normal air-fuel ratio control region, and the amount of purged fuel vapor may be reduced to a lower limit when the air-fuel ratio is outside the normal air-fuel ratio control region.