CONTROL DEVICE FOR A PLUG-IN HYBRID VEHICLE

The present invention suppresses the progress of capacitor deterioration during ignition on while shortening the time until a starter start-up at reverse transition from a CS mode to a CD mode. A control system for a plug-in hybrid vehicle comprises a drive system including a starter motor (1), a transverse engine (2), and a motor/generator (4), and a power supply system including a high voltage battery (21); a capacitor (23); and a hybrid control module (81) that controls charging and discharging of the capacitor (23). In the control system for an FF plug-in hybrid vehicle in which an external charging of the high-power battery (21) is available, the hybrid control module (81) starts the starter, performs mode selection control and charge/discharge control, maintains a capacitor voltage at or below a deterioration free voltage (b) when the CS mode is selected during ignition on, and recharges the capacitor to a starter start-up permission voltage that allows the starter to start when a pre-forecast of the reverse transition from the CS mode to the CD mode is established.