An internal combustion engine (10) includes at least one cylinder (12) having a piston, and a cylinder head containing an inlet duct (3) incorporating an inlet valve 1 to allow flow in only one direction and an exhaust duct incorporating no mechanical flow restricting device and at least one chamber valve (2) through which both inlet and exhaust fluids pass from the ducts (3,4) into and out of the cylinder (12), and a combustion chamber (6) in the cylinder (12) that allows the chamber valve (2) to be significantly open when the piston (5) is at top dead centre enabling a transfer of fluid, fluid flow pressure and pressure waves between the cylinder, and the inlet (3) and exhaust ducts (4).

An internal combustion engine (10) includes at least one cylinder (12) having a piston, and a cylinder head containing an inlet duct (3) incorporating an inlet valve 1 to allow flow in only one direction and an exhaust duct incorporating no mechanical flow restricting device and at least one chamber valve (2) through which both inlet and exhaust fluids pass from the ducts (3,4) into and out of the cylinder (12), and a combustion chamber (6) in the cylinder (12) that allows the chamber valve (2) to be significantly open when the piston (5) is at top dead centre enabling a transfer of fluid, fluid flow pressure and pressure waves between the cylinder, and the inlet (3) and exhaust ducts (4).

A poppet valve, in particular a hollow poppet valve, includes: a valve stem; a valve body having along a longitudinal axis, a first end with a neck portion to which the valve stem is coaxially arranged and having along a longitudinal axis a second end with a first outer contact face portion, the valve body including a cavity with a first opening towards the first end and a second opening towards the second end; and a valve cap coaxially arranged to the valve body on the second end for closing the second opening, the valve cap having a second outer contact face portion to form together with the first outer contact face portion a valve head contact face.

A poppet valve, in particular, a hollow poppet valve, can include a valve stem; a valve cap; a valve body comprising a longitudinal axis with a stem end to which the valve stem is arranged and a cap end to which the valve cap is arranged, the valve body further comprising a cavity with a stem opening towards the stem end and a cap opening towards the cap end; wherein the stem opening of the cavity is configured to be closed by the valve stem and the cap opening of the cavity is configured to be closed by the valve cap; wherein the valve cap comprises a cap wall protruding into the cavity along an interior circumference of the valve cap; and wherein the cap wall comprises a cap wall formation.