CONTROLLER FOR INTERNAL COMBUSTION ENGINE

摘要

Provided is an internal combustion engine including a sparkplug disposed in the vicinity of the center portion of an upper wall surface of a combustion chamber. Tumble flow generated during lean burn operation is controlled such that the tumble flow shape changes according to the engine rotation speed between a first tumble shape (usual tumble shape) in which the flow direction of a gas around the sparkplug at the time of ignition is direction from an intake valve side toward an exhaust valve side in a latter half of a compression stroke, and a second tumble shape (ω tumble shape) in which the flow direction of the gas is reversed in the latter half of the compression stroke from the direction from the intake valve side toward the exhaust valve side to the direction from the exhaust valve side toward the intake valve side.

主权项

1. A controller for an internal combustion engine, the internal combustion engine including:
a combustion chamber; and a sparkplug disposed in the vicinity of a center portion of an upper wall surface of the combustion chamber, the sparkplug being configured to ignite air-fuel mixture, wherein tumble flow is generated inside a cylinder of the combustion chamber during lean burn operation, the controller comprising: an electronic control unit configured to change a shape of the tumble flow between a first tumble shape and a second tumble shape according to an engine rotation speed, the first tumble shape being provided such that flow direction of gas around the sparkplug at the time of ignition of the internal combustion engine is direction from an intake valve side toward an exhaust valve side in a latter half of compression stroke, and the second tumble shape being provided such that the flow direction of the gas is reversed in the latter half of the compression stroke from the direction from the intake valve side toward the exhaust valve side to direction from the exhaust valve side toward the intake valve side due to change to the tumble flow having two swirling flow components with mutually opposite rotation directions, as viewed from above the combustion chamber, in a process in which an in-cylinder gas is compressed in the compression stroke.