To provide a combustion control device of a diesel engine capable of optimizing exhaust gas during a transient operation by suppressing degradation of the exhaust gas such as spike NOx when switching a combustion mode while suppressing complication of control.
In this combustion control device, when switching a normal combustion mode and a premixed combustion mode, if an intake air oxygen concentration is lower than a first predetermined concentration A, a target MFB angle based on a premixed combustion mode map M2 is set, if the intake air oxygen concentration is equal to or higher than a second predetermined concentration B, a target MFB angle based on a normal combustion mode map is set, if the intake air oxygen concentration is equal to or higher than the first predetermined concentration A and lower than the second predetermined concentration B, a target MFB angle which is calculated by interpolating the target MFB angle based on the premixed combustion mode map and the target MFB angle based on the normal combustion mode map in accordance with the intake air oxygen concentration.
KOMATSU FUMITAKA
NAKAYAMA SHINJI
