An ECU executes a program sets a driver requested torque based on the
accelerator operation amount, and sets a torque-boost amount so that the
torque-boost amount increases as the driver requested torque increases,
until the driver requested torque exceeds a predetermined torque T(0).
When the driver requested torque exceeds the predetermined torque T(0),
the torque-boost amount decreases as the driver requested torque
increases. However, the torque obtained by adding the torque-boost amount
to the driver requested torque increases as the accelerator operation
amount increases.