Control system of compression-ignition engine

A control system of a compression-ignition engine, comprising:

• an engine configured to cause combustion of mixture gas inside a combustion chamber;
• an injector attached to the engine and configured to inject fuel into the combustion chamber;
• a spark plug disposed adjacent to the injector and configured to ignite the mixture gas inside the combustion chamber;
• and
• a controller operatively connected to the injector and the spark plug, and configured to operate the engine by outputting a control signal to the injector and the spark plug, respectively, wherein
• after the spark plug ignites the mixture gas to start combustion, unburned mixture gas combusts by self-ignition,
• the controller outputs the control signal to the injector to perform a first-stage injection of the fuel in a period from intake stroke to an early half of compression stroke, and a second-stage injection in a period from a latter half of the compression stroke to an early half of expansion stroke, and
• the controller also outputs the control signal to the injector to control a ratio of the injection amount of the second-stage injection with respect to the injection amount of the first-stage injection to be higher at a high engine speed than at a low engine speed.