Controller for homogeneous charge compression ignition internal combustion engine

A controller for a homogeneous charge compression ignition internal combustion engine which includes a fuel supply device capable of supplying respectively plural types of fuels with mutually different octane numbers to a combustion chamber and adjusting a supplied quantity of the respective plural types of fuels, wherein a fuel-air mixture containing a fuel supplied to the combustion chamber by the fuel supply device and air inhaled to the combustion chamber is ignited to make a combustion by compressing the fuel-air mixture,

• wherein the apparatus has a fuel-cut mode in which a combustion of a fuel-air mixture is not performed in the combustion chamber by switching off forcibly the supply of the plural types of fuels to the combustion chamber, and a normal mode in which a combustion of the fuel-air mixture is performed as a working mode for the homogeneous charge compression ignition internal combustion engine,
• the apparatus comprising:
• a fuel supply control means configured to determine a control operation value group, which is a group of control operation values, for defining a supplied quantity for the respective plural types of fuels to be supplied to the combustion chamber, with respect to the plural types of fuels according to at least a working state of the homogeneous charge compression ignition internal combustion engine by a predefined control rule and to control the fuel supply device according to the determined control operation value group in the normal mode excluding a predefined duration immediately after a return of the working mode from the fuel-cut mode to the normal mode;
• and to determine a return control operation value group obtained by correcting at least one control operation value of a normal control operation value group which is a control operation value group determined according to the predefined control rule and to control the fuel supply device according to the determined return control operation value group in the predefined duration immediately after the return of the working mode from the fuel-cut mode to the normal mode,
• wherein the fuel supply control means determines the return control operation value group so as to increase a proportion of a supplied quantity of a lower-octane fuel in the entire supplied quantity of the respective plural types of fuels to be greater than a normal proportion which is a proportion defined by the normal control operation value group which is determined according to the predefined control rule in the predefined duration immediately after the return of the working mode from the fuel-cut mode to the normal mode.