To properly set the allowable number of revolutions and to realize proper fail-safe, in the variable valve system device of an internal combustion engine to continuously set a valve lift amount by a three-dimensional cam.
An actual regulation amount by a lift amount variable actuator is detected by a shift position sensor at a step S1020. Thereby, it is detected that by which of profiles a valve lift amount is executed within the cam surface of an intake cam. As noted above, since a valve lift amount to decide the allowable number NEG of revolutions togetherwith the spring load and a valve mass of a valve spring is detected, the accurate allowable number NEG of revolutions is set at a step S1030. Thus, the state of the actual number NE of revolutions is properly decided by using the allowable number NEG of revolutions at a step S1040. Namely, when the actual number NE of revolutions exceeds the allowable number NEG of revolutions (when 'YES' at a step S1040), rotation of an engine 11 is properly suppressed through fuel cut at a step S1050.
MORIYA YOSHITO
EINAGA HIDEO
KIKUOKA SHINICHIRO
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