An intake air amount control apparatus for an internal combustion engine is
provided with: an opening control mechanism and a variable valve
mechanism, which control an intake air amount; an intake characteristics
change mechanism for controlling the intake air amount by adjusting a
parameter or parameters different from those of the above two mechanisms;
and an intake amount control device for performing a cooperative control
of these mechanisms upon the occurrence of any normal condition. The
intake air amount control apparatus is also provided with: an abnormality
detection device for detecting an abnormal condition in these three
mechanisms; and a fail-safe device for controlling the intake air amount
of the opening control mechanism out of these three mechanisms and
controlling the other two mechanism, so as to fix their control amounts to
constant values.
