CONTROL DEVICE FOR DIESEL ENGINE

摘要

PROBLEM TO BE SOLVED: To promote mixing of residual gas in a cylinder with new air, obtain good combustion even at large EGR time, so that NOx and PM can be further reduced, in internal EGR control considered effective for simultaneously reducing NOx and PM emitted from a Diesel engine. SOLUTION: In an ECU 50, an exhaust valve 12 is closed earlier that TDC by an amount in accordance with an operating condition of a Diesel engine, and an intake valve 11 is opened later than a crank angle or more early closed by the exhaust valve 12 relating to the TDC. The exhaust valve 12 is closed earlier than this TDC with burned gas left in a cylinder, but by opening the intake valve 11 later than this early closed crank angle or more, the intake valve is opened from a condition that a negative pressure is temporarily generated in the cylinder, hear new air is allowed to rapidly flow in. In this way, mixing of the burned gas in the new air is accelerated.