Abstract: In an automotive power plant including a combustion engine, intake and exhaust passages communicated with a combustion chamber for an introduction of an air-fuel mixture into and a discharge of exhaust gases from the combustion chamber, respectively, a fuel injector for injecting a controlled amount of fuel into the combustion chamber together with air sucked through the intake passage, and a throttle valve of which opening is adjustable for controlling the flow of the air through the intake passage, a fuel control system for determining the amount of fuel to be injected into the combustion chamber in dependence on the amount of air being sucked.

Abstract: A method and apparatus for electronically controlling injection of fuel into an engine selectively uses fuel injection control based on an intake air flow rate sensing system (e.g. L-J system fuel injection control) and fuel injection control based on a speed density system (e.g. D-J system fuel injection control), this depending upon the amount of intake air. In an engine operating region where a control relationship between these two forms of fuel injection control is constant, e.g. in an operating region where the amount of intake air is low, the relationship is stored. In a region of high air intake, where the relationship no longer holds, the amount of fuel injection in the speed density system is corrected on the basis of the aforementioned relationship.

Abstract: A fuel injection control system in an automobile engine comprising an intake system for the supply of air towards the engine and including an air flow sensor, an exhaust system for the discharge of exhaust gases, a supercharger in the intake system for compressing the air flowing towards the engine, and a secondary air supply passage extending between the intake and exhaust systems for the introducing of a portion of the compressed air into the exhaust system and including a secondary air flow sensor. During a normal operating condition, fuel is injected into the engine in a quantity dependent on the difference between the air flow detected by the air flow sensor and the secondary air flow detected by the secondary air flow sensor, but in the event of trouble occurring in the secondary air flow sensor, the fuel is injected in a quantity dependent on the air flow detected by the air flow sensor.