Control apparatus and control method for internal combustion engine

#The disclosure of Japanese Patent Application No. 2008-128480 filed on May 15, 2008 including the specification, drawings and abstract is incorporated herein by reference in its entirety.

#1. Field of the Invention

#The invention relates to a control apparatus and a control method for an internal combustion engine that uses a fuel containing an alcohol component.

#The features, advantages, and technical and industrial significance of this invention will be described in the following detailed description of example embodiments of the invention with reference to the accompanying drawings, in which like numerals denote like elements, and wherein:

#FIG. 1 is a schematic configuration diagram showing a control apparatus for an internal combustion engine according to an embodiment of the invention, and a configuration around the internal combustion engine;

#FIG. 2 is a flowchart showing steps of a start routine for starting the internal combustion engine in the embodiment;

#Hereinafter, a control apparatus for an internal combustion engine according to an embodiment of the invention will be described with reference to FIG. 1 to FIG. 5. FIG. 1 shows an internal combustion engine 10 and a configuration around the internal combustion engine 10 in the embodiment. As shown in FIG. 1, a piston 12 is housed in each cylinder 11 of the internal combustion engine 10 in a manner such that the piston 12 reciprocates. The piston 12 is connected to a crankshaft 15 through a connecting rod 17. A crank position sensor 15a, which detects the rotational phase of the crankshaft 15, is provided for the crankshaft 15. Further, a water jacket 16 is provided in the internal combustion engine 10. A coolant, which cools the internal combustion engine 10, flows in the water jacket 16. Also, a coolant temperature sensor 16a, which detects the temperature of the coolant flowing in the water jacket 16, is fitted to the internal combustion engine 10.

#An intake camshaft (not shown) and an exhaust camshaft (not shown) are rotated due to the rotation of the crankshaft 15. An intake valve 25 is pressed downward due to the rotation of the intake camshaft, and thus, communication is provided between an intake port 24 and a combustion chamber 13. An exhaust valve 26 is pressed downward due to the rotation of the exhaust camshaft, and thus, communication is provided between an exhaust port 27 and the combustion chamber 13. An ignition plug 14 is provided to face the combustion chamber 13.

#An intake passage 20 is connected to the combustion chamber 13 in each cylinder 11 through the intake port 24. An exhaust passage 30 is connected to the combustion chamber 13 through the exhaust port 27. An air-fuel ratio sensor 30a is fitted to the exhaust passage 30. The air-fuel ratio sensor 30a detects a value corresponding to the concentrations of oxygen and unburned fuel in exhaust gas that flows in the exhaust passage 30.