Control method for internal combustion engine system, and internal combustion engine system

An internal combustion engine system for a vehicle, including an internal combustion engine, an electric drive unit adapted to start up the internal combustion engine, a starter battery for use as an electric power source for activating the electric drive unit, an electric load that is activated in a stopped-state of the internal combustion engine, a general-purpose battery for supplying electric power to the electric load and running control unit configured to govern a running control of the internal combustion engine, the running control unit comprising:

• an automatic stop unit operable, upon satisfaction of a given automatic stop condition, to automatically stop the internal combustion engine being running;
• a restart unit operable, upon satisfaction of a given restart condition after the internal combustion engine is automatically stopped, to allow electric power to be supplied from the starter battery to the electric drive unit so as to automatically restart the internal combustion engine;
• a post-attached load detection unit operable to detect the presence or absence of a post-attached load to be supplied with electric power from the starter battery wherein the post-attached load is provided in addition to electric loads in conformity with specifications of the vehicle and connected to the starter battery, based on a discharging status of the starter battery due to the post-attached load in the automatically stopped state of the internal combustion engine;
• and
• a forcible restart unit operable, when the post-attached load is detected as a detection result of the post-attached load detection unit, to restart the internal combustion engine irrespective of the satisfaction or non-satisfaction of the restart condition.