Patent ID: 8701617

Claim:
A reciprocating piston internal combustion engine, comprising: an engine block supporting at least one cylinder enclosing a piston slidably and reciprocably disposed within the cylinder; an output shaft supported by the engine block; a power linkage which operably conducts power developed by reciprocation of the piston within its associated cylinder to the output shaft; and a cylinder head defining therein a combustion chamber for each cylinder, an induction path disposed to conduct fresh combustion air to each cylinder, and an exhaust path disposed to conduct spent combustion products away from each cylinder, wherein the combustion chamber closes one end of the cylinder; for each cylinder, an intake valve disposed in the induction path, which is disposed to open and close the induction path to flow of fresh combustion air to each cylinder, and having an intake valve head; for each cylinder, an exhaust valve disposed in the exhaust path to open and close the combustion chamber to the exhaust path, and having an exhaust valve head and wherein the axis of each cylinder defines a reference plane disposed perpendicularly to the axis and located between the valves and the piston; that portion of the head of the intake valve facing the combustion chamber defines an intake valve head plane disposed at an acute angle to the reference plane; and the combustion chamber comprises a bulge formed in the open space of the combustion chamber, which said bulge projects away from the piston and opens towards the piston, wherein the bulge has a distal portion located further from the piston than any part of the head of the intake valve is located from the piston, and wherein the bulge has a wall portion located proximate the head of the intake valve which has a slope which is arranged at an acute angle to the reference plane which is greater than the acute angle of the intake valve head plane relative to the reference plane, wherein said wall portion is located proximate the head of the intake valve, said wall portion being flat and linear for at least a part of its extent from the head of the intake valve to that point of the bulge which is farthest from the piston when considered in a cross section, said wall portion also intersecting with the head of the intake valve, and wherein the angle existing between the wall portion which is flat and linear and the valve head plane of the head of the intake valve is in a range of ten to twenty degrees.