Internal combustion engine with dual induction system and with fuel

Abstract

A spark ignition fuel injection reciprocatory internal combustion engine with dual induction system has within a cylinder head a primary intake passage to direct air fuel mixture charge into a cylinder to swirl therein and a secondary intake passage to direct air charge into the cylinder in such a direction as to impede the swirling motion of the air fuel mixture charge, thereby to maintain the volumetric efficiency of the engine at a sufficiently high level. A fuel injector is so positioned as to discharge fuel into the primary intake passage. An air flow sensor is provided upstream of primary and secondary throttle valves to detect the total of flow of induction air fed to the engine so that fuel is discharged at a rate proportional to the total induction air flow. Under engine operating conditions when only the primary throttle valve opens, air fuel mixture charge will swirl at a sufficiently high rate as to enhance evaporation and dispersion of fuel droplets. Under engine operating conditions when both the primary and secondary throttle valves open, the air fuel mixture charge issuing from the primary intake passage is enriched and air charge from the secondary intake passage impedes swirling motion of enriched air fuel mixture charge from the primary intake passage to enhance evaporation and dispersion of fuel droplets.