Diesel engine

The invention relates to a diesel engine comprising a sensor that detects an engine temperature; and a combustion-temperature control device that adjusts a combustion temperature of the engine depending on engine speed, engine load and the engine temperature detected by the sensor. The invention aims to provide an improved engine having an enhanced heating performance and stable combustion during the cold engine warm-up period. Therefore, the invention proposes that an ignition-delay-duration control device adjusts an ignition delay duration, depending on the engine speed, the engine load, and the engine temperature detected by the sensor, so as to change a rate of premix combustion to diffusion combustion, the ignition delay duration being defined as a time duration between a start of fuel-injection and a start of ignition.