An object of the present invention is to provide a technology that enables to enhance the effect of decreasing the NOx emission achieved by an exhaust gas purification system as a whole while favorably achieving both reduction in the amount of NOx generate...

Engine systems and methods for accomplishing regeneration of a NOx adsorber (28) using in-cylinder post-injection in a way that creates a lean-rich transition (Figure 3) for regenerating the NOx adsorber while attenuating engine torque output fluctuations ...