Method and device for controlling fuel injection of diesel engine

A fuel injection control device of a diesel engine for performing a plurality of fuel injections to cause a plurality of combustions inside a cylinder in one combustion cycle, comprising:

• a fuel supply device configured to inject fuel into the cylinder;
• and
• a controller that computes an oxygen concentration inside the cylinder based on at least one of an intake air amount, a boost pressure, an exhaust gas recirculation ratio, an exhaust gas flow rate, an exhaust gas oxygen concentration, or an air-fuel ratio, wherein the controller is operatively coupled to the fuel supply device and is configured to:
• control the fuel supply device to perform, on compression stroke, the plurality of fuel injections at substantially even injection intervals, wherein the injection intervals are increased in response to detecting a decrease in the oxygen concentration;
• and
• perform, after the plurality of fuel injections, an additional fuel injection having a larger injection amount than a respective injection amount of each of the plurality of fuel injections, near a top dead center of the compression stroke.