An engine control device is configured to prevent surging in an engine
equipped with both a variable-nozzle turbocharger and an EGR device while
curbing costs by utilizing existing equipment and avoiding undesirable
secondary effects. When the engine is in a prescribed engine operating
state in which the fuel injection quantity should be reduced, the EGR
quantity delivered by the EGR device is reduced to a value lower than the
normal value and the opening degree of the turbine nozzle of the
turbocharger is increased. The prescribed engine operating state is
defined to exist when the vehicle is decelerating and when the fuel
injection quantity is decreased after regeneration of the NOx trapping
catalytic converter.