In an OFF condition of an ECO switch, a stop decision reference value
Wstop is set to a value W1 (step S420). In an ON condition of the ECO
switch, the stop decision reference value Wstop is set to a value W2
(step S430). When an output limit Wout of a battery set according to a
battery temperature and a state of charge of the battery is not less than
the set stop decision reference value Wstop, the engine is permitted to
stop (step S450). When the output limit Wout is less than the set stop
decision reference value Wstop, the engine is prohibited from stopping
(step S460). The value W1 is specified as a value of electric power
required for a smooth restart of the engine after its stop during a drive
of the vehicle. The value W2 is specified to be close to a value of
minimum electric power required for a restart of the engine after its
stop during a drive of the vehicle and is set to be smaller than the
value W1.