Patent ID: 7637244

Claim:
An intake air amount controlling apparatus of an internal-combustion engine, the apparatus comprising: an intake manifold that is branched from an intake manifold collecting portion of the engine, the intake manifold communicating with an intake port of a cylinder head of a corresponding cylinder; a throttle valve provided in the intake manifold of the cylinder; and a throttle bore provided in the intake manifold, the throttle bore having a curved surface, wherein the throttle valve rotates such that one half of the throttle valve contacts with the curved surface of the throttle bore until the throttle valve reaches a predetermined opening degree, thereby preventing an air flow via the one half of the throttle valve from entering the intake port while allowing an air flow via the other half of the throttle valve to enter the intake port; and wherein areas of cross sections, which are orthogonal to an air flow passing through the intake manifold, of the intake manifold at an upstream end and a downstream end of the curved surface of the throttle bore are larger than an area of a cross section, which is orthogonal to an air flow entering the intake port, crossing an open face at which the intake manifold communicates with the intake port.