Control device for internal combustion engine

摘要

An intake passage (26) of an engine has a main flow channel (26A) provided with a throttle valve (32) and a bypass flow channel (26B) for bypassing the throttle valve (32). A bypass quantity adjusting mechanism (33) is provided in the bypass flow channel (26B) for adjusting a bypass quantity. A control device (40) for an engine includes a mixing ratio determining part (43) for detecting or estimating a mixing ratio of alcohol of a fuel and a storing part (42) for storing the determined mixing ratio of ethanol. The control device (40) controls the bypass quantity adjusting mechanism (33) so that a bypass quantity before first explosion would be smaller than a bypass quantity after first explosion in the case that the mixing ratio of ethanol, the mixing ratio being stored in the storing part (42), is equal to or more than a predetermined value.