Compression ignition engine with supercharger

A compression ignition engine with a supercharger, comprising:

• an engine body having a cylinder where a combustion chamber is formed;
• the supercharger, configured to boost intake air to the combustion chamber of the engine body;
• one or more valves configured to switch a state between a first state in which the intake air is boosted by the supercharger and a second state in which the intake air is not boosted by the supercharger;
• a fluid temperature adjuster comprising a grille shutter provided in front of a radiator and configured to adjust a temperature of engine coolant configured to be supplied to the radiator from the engine body to cool the engine body, the grille shutter comprising a plurality of flappers which rotate on respective axes extending in a vehicle width direction;
• and
• a controller comprised of circuitry, configured to control operation of the engine body including operations of the one or more valves and the fluid temperature adjuster,
• wherein when the controller determines that an operating state of the engine body is in a high-load operating range where an engine load is more than a given load, the controller controls a combustion mode of the engine body to be in a compression ignition combustion mode in which an unburnt mixture gas is self-ignited during flame propagation combustion of a mixture gas caused by jump-spark ignition inside the combustion chamber,
• wherein when the controller determines that the operating state of the engine body is in the high-load operating range, causing the one or more valves to be in the first state, while when the operating state of the engine body is in a low-load operating range in which the load is lower than the given load, causing the one or more valves to be in the second state,
• wherein when the controller determines that the operating state of the engine body is in the high-load operating range, the controller outputs a control signal to the grille shutter so that an opening of the grille shutter becomes larger, compared with the opening of the grille shutter when the operating state of the engine body is in the low-load operating range,
• wherein the fluid temperature adjuster comprises the grille shutter and a radiator fan configured to adjust an amount of air passing through the radiator, the radiator fan provided rearward of the radiator,
• wherein when the operating state of the engine body is in the high-load operating range, the controller increases a rotational speed of the radiator fan, compared with the rotational speed of the radiator fan when the operating state of the engine body is in the low-load operating range, and
• wherein the controller controls the grille shutter and the radiator fan such that:
• a detection result of a fluid temperature sensor becomes a first fluid temperature when the operating state of the engine body is in a low-speed operating range and in the low-load operating range, and
• the opening of the grille shutter is fully closed and the rotational speed of the radiator fan is set to zero when the detection result of the fluid temperature sensor is below the first fluid temperature.