Internal combustion engine and method for performing a mode switch in said engine

An automotive system, comprising:

• an internal combustion engine, comprising:
• at least one cylinder;
• a piston whose compression action causes a mixture of air and fuel within a combustion chamber of said cylinder to be ignited;
• at least one inlet valve for admitting gas which includes fresh air into said cylinder;
• at least one exhaust valve for exhausting combusted gases from said cylinder;
• a fuel injection system having at least one fuel injector, through which fuel is injected into said combustion chamber of said cylinder;
• an intake air charging system for supplying air under pressure to an engine air intake manifold;
• at least one sensor for measuring an engine operating parameter;
• and
• a controller operating said engine in a first combustion mode, said controller subsequently switching engine operation to a second combustion mode wherein manifold pressure in said second combustion mode is lower than manifold pressure in said first combustion mode;
• and controlling said intake air charging system to cause a temporary airflow reversal thereby equalizing a pressure difference between said intake valve and said exhaust valve.