PURPOSE: To reduce pumping loss by controlling an air intake and exhausting timing variable device when fuel supply is stopped or before fuel is stopped after fuel supply stop conditions are satisfied so as to increase the period during which air intake and exhaust ports are open concurrently.
CONSTITUTION: When the conditions for fuel cut are satisfied in decelerating operation or the conditions for fuel cut are satisfied in the operation at the maximum speed, an worm gear 24 is driven by an air intake valve drive motor 23 so as to control a second air intake valve 12, a period during which the valve opening period of the second air intake valve 12 and the valve opening period of an exhaust valve 13 is overlapped is made larger than the overlapped amount of valve opening period between the first air intake valve 11 and the exhaust valve 13, and then fuel from a fuel injection valve 9 is cut off. In this case, because the second air intake valve 12 is opened so as to overlap it with the exhaust valve 13, a pumping loss is reduced. Then fuel cut is started and, at the same time the second air intake valve 12 is returned gradually in increments of a specified angle for each specified period so as to suppress pumping loss.
MURAKAMI KENJI
ICHIKAWA TAKAHIRO
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