STOP CONTROL APPARATUS FOR ENGINE, ENGINE SYSTEM, AND VEHICLE

A stop control apparatus for an engine includes a determination unit which determines whether or not an automatic stop condition is satisfied and a control unit which stops the engine when the automatic stop condition is satisfied. The control unit executes oxygen concentration adjustment control which controls a throttle valve and an EGR valve such that an oxygen concentration in an intake passage on a downstream side of a connection portion with an EGR passage has a predetermined target value Dx in a period until the engine is completely stopped after fuel cut is executed. The oxygen concentration adjustment control includes first control which sets the throttle valve to a valve-open state such that the oxygen concentration is elevated and a second control which closes the throttle valve at a time point when the oxygen concentration is elevated to the target value.