Importance

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Abstract

A cylinder head for a four-valve per cylinder internal combustion engine comprises a bowl-shaped combustion chamber recess on a lower surface which cooperates with a piston in a cylinder to form a combustion chamber. The combustion chamber recess has first and second exhaust openings, and first and second intake openings. First and second exhaust ports extend from the first and second exhaust openings to an exhaust outlet through an exhaust side wall of the cylinder head. First and second intake ports, divided by a septum, extend from the first and second intake openings, along a curved flow path, to an intake passage. The intake passage delivers intake charge from an intake inlet in an intake side wall of the cylinder head to the first and second intake ports. The first and second intake ports have first and second intake valves to regulate flow of intake charge through the intake valve openings. The intake passage has a port protrusion including a swirl-inducing ramp, on an upstream side to redirect a portion of the intake charge entering the first intake port and inducing swirl about a stem of the first intake valve, and a back angled ramp on a downstream side so as to reduce hindrance of induced swirl.

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First Claim