Control system for direct injection diesel engine

A control system for a direct injection diesel engine having a fuel injection valve (15) for injecting fuel whose quantity corresponds to engine load directly into a cylinder (14) and an intake throttle valve (23) provided in an intake passage (2) comprises an intake throttle valve controller (41) which performs a control operation for reducing the amount of intake air by closing the intake throttle valve (23) to thereby make the air-fuel ratio in the cylinder (14) smaller than the theoretical air-fuel ratio during warm engine idling, and a fuel injection controller (40) which controls the fuel injection valve (15) to make pilot injection of the fuel during execution of the control operation for reducing the amount of intake air.