VALVE SYSTEM OF INTERNAL COMBUSTION ENGINE

摘要

PROBLEM TO BE SOLVED: To prevent or suppress the blow back of intake air and suppress the lowering of fuel economy due to the lowering of an effective expansion ratio by starting to open an intake valve when a pressure in a combustion chamber is low. SOLUTION: The valve characteristic variable mechanism M of a valve system 40 controls an internal EGR rate by controlling an overlapping period and a non-overlapping period. The valve characteristic variable mechanism M comprises a control mechanism M3 swinging an intake link mechanism connected to an intake cam and an exhaust link mechanism connected to an exhaust cam 54 about a camshaft 50 and a drive mechanism driving the control mechanism M3. The control mechanism M3 connects the drive mechanism to each link mechanism so that the spark-retard angle of an intake valve 22 at an opening time by an intake link mechanism is larger than the spark-advance angle of an exhaust valve 23 at a closing timing by an exhaust link mechanism relative to the same drive amount of the drive mechanism in the increasing direction of an internal EGR rate. COPYRIGHT: (C)2005,JPO&NCIPI