Diesel engine

A diesel engine having a main combustion chamber and an auxiliary combustion chamber communicating with the main combustion chamber, the diesel engine comprising:

• an injector having an injection portion that is provided facing an inside of the auxiliary combustion chamber, is exposed to an internal space of the auxiliary combustion chamber, and injects fuel into the internal space;
• a control device that controls an injection timing of the fuel injected from the injection portion;
• and
• exhaust circulating means that circulates exhaust of the diesel engine wherein,
• the control device controls the injection timing of main injection of the diesel engine and pre-injection of the diesel engine performed prior to the main injection and executes control such that, by ensuring a premixing period of the pre-injection from start of the pre-injection until ignition of a first air-fuel mixture of the fuel injected by the pre-injection and air, the first air-fuel mixture, which is homogenous and lean, is generated in the auxiliary combustion chamber by the fuel injected by the pre-injection and the air, and the premixing period of the main injection from the start of the main injection until ignition of a second air-fuel mixture of the fuel injected by the main injection and the air is ensured,
• the fuel for the pre-injection is injected at a crank angle of the diesel engine of 120° before top dead center or after in a compression stroke of the diesel engine,
• the first air-fuel mixture ignites at the crank angle after 10° before the top dead center in the compression stroke and prior to the top dead center in the compression stroke, and
• the fuel for the main injection is injected after a peak heat generation rate of the diesel engine generated by ignition of the first air-fuel mixture and before the top dead center in the compression stroke.