COMBUSTION CONTROL DEVICE AND METHOD FOR AN INTERNAL COMBUSTION ENGINE

In a control device 50A, an actual compression ratio calculation unit 502 calculates an actual compression ratio µ from an air supply pressure Ps, a cylinder pressure before ignition Pc and an air supply temperature Ts. A deposit deposition estimation unit 504 determines the deposit deposition state of a combustion chamber 18 from a deviation µ between the actual compression ratio µ and a design compression ratio µ'. When the deviation µ exceeds a threshold value, ignition timing or air-fuel ratio being operation conditions of an internal combustion engine is corrected based on a correction map 508 so as to suppress deterioration of exhaust gas.