Combustion chamber structure for a spark ignition engine

Claim 1

A spark ignition, four-stroke cycle, internal combustion engine of the type that includes a cylinder block with at least one cylinder, a piston in the cylinder reciprocable through a predetermined stroke volume, a cylinder head formed with a single-chamber combustion space opening into the stroke volume of the cylinder and an intake port equipped with a poppet-type intake valve opening directly into the chamber, and means for supplying a stratified charge of air and carbureted fuel-rich mixture in sequence through the intake port during the intake stroke of the piston, but the configuration of the passageway formed by the intake port, the poppet-type intake valve and the single-chamber combustion space being such that the velocity of the charge entering the stroke volume of the cylinder is higher adjacent to at least a portion of the circumferential wall of the cylinder than it is in the rest of the cylinder, thereby causing undesirable mixing of the stratified charge, wherein the improvement comprises: a peripheral barrier located near the opening from the combustion chamber into the stroke volume of the cylinder and projecting inwardly from at least the portion of the circumferential wall of the cylinder in the way of the higher velocity portion of the incoming charge in order to create approximately uniform velocity of the incoming charge at all points on a plane normal to the direction of flow past the barrier.