CONTROL DEVICE FOR INTERNAL-COMBUSTION ENGINE

摘要

The objective of the present invention is, in an internal-combustion engine using alcohol fuel, to prevent blow-by gas from reaching a catalyst when the fuel is cut, and to control the increase in the oil dilution amount due to use of alcohol fuel, while protecting the catalyst. An engine (10) is provided with a PCV mechanism (50) for injecting blow-by gas in a crankcase (18) into an intake system. When fuel is cut with the PCV mechanism (50) in operational condition, the opening of a throttle valve (26) during fuel cut is set on the basis of the dilution level of the oil in the lubricant. It is therefore possible to adjust the throttle opening during fuel cut according to the amount of blow-by gas emitted, reducing intake negative pressure to an appropriate level. Therefore, it is possible to suppress the amount of blow-by gas introduced into the intake system that was blown out of the crankcase (18) due to intake negative pressure during the fuel cut.