Engine control apparatus

An engine control apparatus, comprising:

• an engine including an injector configured to inject fuel into a combustion chamber and an ignition plug configured to ignite air-fuel mixture of the fuel and air in the combustion chamber;
• and
• a controller configured to control the injector and the ignition plug to switch a combustion mode based on a required torque of the engine, wherein
• the combustion mode includes:
• a spark ignition combustion of gasoline fuel with ignition;
• a first homogenous charge compression ignition combustion of reformed fuel without ignition, the reformed fuel being obtained by reforming a portion of the gasoline fuel into peroxide;
• a second homogenous charge compression ignition combustion of the reformed fuel with ignition;
• and
• a diffusion combustion of the reformed fuel without ignition, wherein the controller controls the injector and the ignition plug:
• to switch the combustion mode to the second homogenous charge compression ignition combustion when the required torque is less than a first predetermined value;
• to switch the combustion mode to the first homogenous charge compression ignition combustion when the required torque is equal to or more than the first predetermined value and less than a second predetermined value larger than the first predetermined value;
• to switch the combustion mode to the spark ignition combustion when the required torque is equal to or more than the second predetermined value and less than a third predetermined value larger than the second predetermined value;
• and
• to switch the combustion mode to the diffusion combustion when the required torque is equal to or more than the third predetermined value.