Control apparatus for internal combustion engine

摘要

It is an object of this invention to restrain blow-by gas from reaching a catalyst during fuel cutoff, and protect the catalyst while coping with an increase in oil dilution amount resulting from the use of alcohol fuel, in an internal combustion engine that uses the alcohol fuel. An engine is equipped with a PCV mechanism that introduces blow-by gas in a crankcase into an intake system. Besides, when fuel cutoff is executed with the PCV mechanism in operation, an opening degree of a throttle valve during fuel cutoff is set on the basis of an oil dilution amount in lubricating oil. Thus, the throttle opening degree during fuel cutoff is adjusted in accordance with a generation amount of blow-by gas, so that an intake negative pressure can be appropriately reduced. Accordingly, during fuel cutoff, the amount of blow-by gas that is sucked out from the crankcase due to the intake negative pressure and introduced into the intake system can be held small.

主权项

1. A control apparatus for an internal combustion engine, characterized by comprising:
a throttle valve that is provided in an intake passage of the internal combustion engine to adjust an amount of intake air that is sucked into a cylinder via the intake passage; a fuel injection valve that injects alcohol fuel into the intake passage and/or the cylinder; a PCV mechanism that introduces, into the intake passage, evaporative fuel that has evaporated from lubricating oil in a crankcase of the internal combustion engine; an oil dilution amount estimation unit configured to estimate an oil dilution amount as an amount of fuel that has been mixed with the lubricating oil in the crankcase; and a fuel cutoff throttle control unit configured to set an opening degree of the throttle valve during fuel cutoff on a basis of the oil dilution amount when fuel cutoff is executed with the PCV mechanism in operation, wherein the fuel cutoff throttle control unit is configured to increase the opening degree of the throttle valve during fuel cutoff as the oil dilution amount increases.