Patent ID: 6877464

Claim:
A spark-ignition engine controller for a multi-cylinder spark ignition engine set such that the combustion cycle of each cylinder has a predetermined phase difference, said spark-ignition engine controller comprising: an operation mode controller for performing control such that a control mode for engine intake, exhaust, and combustion in a partial load range of the engine is set as a special operation mode, and in the special operation mode a two-cylinder connection is maintained in which burned gas discharged in the exhaust stroke of a preceding cylinder of a pair of cylinders having an overlapping exhaust stroke and intake stroke is introduced as is into a following cylinder during the intake stroke thereof through an intercylinder gas channel and exhaust gas discharged from the following cylinder is introduced into an exhaust passage, while combustion is performed in the preceding cylinder at a leaner air-fuel ratio than the stoichiometric air-fuel ratio, and combustion is performed in the following cylinder by feeding fuel to the lean air-fuel ratio burned gas introduced into the following cylinder from the preceding cylinder; a combustion condition controller for performing control such that in the operating range set as said special operation mode, combustion is performed in the following cylinder by compression ignition; and a fuel injection controller which, in an operating condition in a low load range within the compression ignition range of said following cylinder, sets the fuel injection timing into the following cylinder in an intake stroke and which, in an operating condition in a high load range within the compression ignition range of said following cylinder, retards the fuel injection timing into the following cylinder to be in a later half of the compression stroke.