Intake control device for an engine

An intake control device for an engine, comprising:

• an intake manifold including a main intake manifold and an auxiliary intake manifold, the main intake manifold removably mounted to an upper end of the auxiliary intake manifold, and the auxiliary intake manifold removably mounted to an upper end of a cylinder head;
• a partition plate provided in an intake passage extending obliquely upward from a combustion chamber, as seen along an axial direction of a crankshaft, arranged to divide the intake passage into an upper intake passage and a lower intake passage, the partition plate including an upstream partition plate and a downstream partition plate;
• and
• a tumble control valve provided in a vicinity of the upstream partition plate in the upper intake passage and arranged to open or close at least a portion of the upper intake passage;
• wherein
• a bottom wall arranged at an inlet of the lower intake passage is inclined at an angle α between approximately 25° to approximately 30° and spaced away from the upstream partition plate by a gradually increasing distance as the bottom wall extends upstream in the lower intake passage;
• a portion of the lower intake passage located downstream from the bottom wall extends parallel or substantially parallel to the downstream partition plate;
• a portion of the lower intake passage located upstream from the bottom wall extends parallel or substantially parallel to the upstream partition plate;
• when the tumble control valve is closed, intake air changes direction such that the intake air contacts the bottom wall and is directed towards the partition plate;
• and
• the upstream partition plate, the tumble control valve, and the bottom wall are arranged within the auxiliary intake manifold.