Combustion control device for compression autoignition engine

A combustion control device for a compression autoignition engine, the combustion control device comprising:

• an engine configured to cause autoignition of air-fuel mixture in a combustion chamber formed by a cylinder and a piston;
• a state quantity setting device mounted to the engine, the state quantity setting device configured to set an inside of the combustion chamber to a desired state by adjusting introduction of fresh air and burned gas into the combustion chamber;
• an injector mounted to a roof of the combustion chamber, the injector configured to inject fuel into the combustion chamber;
• a spark plug disposed so as to face the inside of the combustion chamber, the spark plug configured to ignite air-fuel mixture in the combustion chamber;
• a controller connected to the state quantity setting device, the injector, and the spark plug, the controller configured to operate the engine by outputting control signals to the state quantity setting device, the injector, and the spark plug;
• and
• a sensor connected to the controller, the sensor configured to detect a parameter regarding an operation state of the engine and output a detection signal to the controller, wherein
• the piston has a cavity that is recessed from an upper surface of the piston and that faces the injector,
• the injector has a plurality of holes each having a hole axis inclined relative to a cylinder axis of the cylinder and injects the fuel toward the upper surface of the piston,
• the spark plug receives a control signal from the controller and ignites the air-fuel mixture at predetermined ignition timing such that the ignited air-fuel mixture is combusted by flame propagation and then unburned air-fuel mixture in the combustion chamber is combusted by autoignition, and
• the controller outputs a control signal to the injector such that, in a compression stroke, the fuel is injected at specific timing at which a line obtained by extending the axis of each hole of the injector overlaps with a specific portion including an opening edge of the cavity in the upper surface of the piston.