A combustion chamber system comprising: a combustion chamber defined around an axis and into which an air-fuel mixture is to be charged; ignition means disposed within said combustion chamber for igniting the air-fuel mixture disposed within said combustion chamber; and a single component intake/exhaust valve movably disposed within said combustion chamber between first CLOSED and second OPEN positions for controlling the intake of air into said combustion chamber and the exhaust of combustion products out from said combustion chamber; characterized in that a first combustion air intake port is defined within an upper side wall portion of said combustion chamber; a second combustion product exhaust port is defined within an upper wall portion of said combustion chamber; and said single component intake/exhaust valve has an annular configuration which permits combustion air to enter said first combustion air intake port for flow into said combustion chamber, and for permitting combustion products to be exhausted from said combustion chamber through said second combustion product exhaust port, when said single component intake/exhaust valve is disposed at said second OPEN position, and prevents combustion air from entering said first combustion air intake port for flow into said combustion chamber, and for preventing combustion products from being exhausted from said combustion chamber through said second combustion product exhaust port, when said single component intake/exhaust valve is disposed at said first CLOSED position; and said annularly configured single component intake-exhaust valve and said upper wall portion of said combustion chamber defining said second combustion product exhaust port comprise oppositely oriented flanged portions (116, 118) such that when said single component intake/exhaust valve is disposed at said first OPEN position, the combustion air entering said first combustion air intake port for flow into said combustion chamber will traverse a sinusoidal flow path. a combustion chamber defined around an axis and into which an air-fuel mixture is to be charged; ignition means disposed within said combustion chamber for igniting the air-fuel mixture disposed within said combustion chamber; and a single component intake/exhaust valve movably disposed within said combustion chamber between first CLOSED and second OPEN positions for controlling the intake of air into said combustion chamber and the exhaust of combustion products out from said combustion chamber; characterized in that a first combustion air intake port is defined within an upper side wall portion of said combustion chamber; a second combustion product exhaust port is defined within an upper wall portion of said combustion chamber; and said single component intake/exhaust valve has an annular configuration which permits combustion air to enter said first combustion air intake port for flow into said combustion chamber, and for permitting combustion products to be exhausted from said combustion chamber through said second combustion product exhaust port, when said single component intake/exhaust valve is disposed at said second OPEN position, and prevents combustion air from entering said first combustion air intake port for flow into said combustion chamber, and for preventing combustion products from being exhausted from said combustion chamber through said second combustion product exhaust port, when said single component intake/exhaust valve is disposed at said first CLOSED position; and said annularly configured single component intake-exhaust valve and said upper wall portion of said combustion chamber defining said second combustion product exhaust port comprise oppositely oriented flanged portions (116, 118) such that when said single component intake/exhaust valve is disposed at said first OPEN position, the combustion air entering said first combustion air intake port for flow into said combustion chamber will traverse a sinusoidal flow path.