Abstract: An engine includes a variable valve mechanism capable of switching a valve characteristic to a first valve characteristic according to which at least one of an operation of pre-opening an intake valve during an exhaust stroke prior to a valve opening time in an intake stroke and an operation of re-opening an exhaust valve during the intake stroke subsequently to the opening/closing thereof during the exhaust stroke is performed, and to a second valve characteristic according to which neither the pre-opening of the intake valve nor the re-opening of the exhaust valve is performed. In the engine, when the valve characteristic is the first valve characteristic, if the presence of a request for switching to the second valve characteristic resulting from an increase in engine load is detected, a pressure reducing operation for reducing the pressure in an exhaust passage of the engine is performed.

Abstract: An engine 1 includes a variable valve mechanism 18 capable of switching a valve characteristic to a first valve characteristic according to which at least one of an operation of pre-opening an intake valve 14 during an exhaust stroke prior to a valve opening time in an intake stroke and an operation of re-opening an exhaust valve 15 during the intake stroke subsequently to the opening/closing thereof during the exhaust stroke is performed, and to a second valve characteristic according to which neither the pre-opening of the intake valve 14 nor the re-opening of the exhaust valve 15 is performed. In the engine 1, when the valve characteristic is the first valve characteristic, if the presence of a request for switching to the second valve characteristic resulting from an increase in engine load is detected, a pressure reducing operation for reducing the pressure in an exhaust passage 40 of the engine 1 is performed (e.g., a regulate valve 68 is opened).