Patent ID: 8509979

Claim:
A control apparatus for a hybrid vehicle, the hybrid vehicle comprising: a power element including a rotating electrical machine and an internal combustion engine; a power transmission mechanism comprising a plurality of rotational elements which mutually perform differential operation and which include a first rotational element capable of adjusting a rotational speed by using the rotating electrical machine, a second rotational element coupled with a drive shaft connected to an axle, and a third rotational element coupled with the internal combustion engine; and a locking mechanism capable of changing a state of the first rotational element between a lock state in which the first rotational element cannot rotate and a non-lock state in which the first rotational element can rotate, wherein the power transmission mechanism is configured such that the rotating electrical machine functions as a reaction element that provides a reaction torque to the internal combustion engine, and the hybrid vehicle is configured such that a speed change mode is configured to be switched between a stepless speed change mode and a fixed speed change mode, the stepless speed change mode being a mode in which the first rotational element is in the non-lock state such that a transmission gear ratio, a ratio between a rotational speed of the internal combustion engine and a rotational speed of the drive shaft, is continuously variable, the fixed speed change mode being a mode in which the first rotational element is in the lock state such that the transmission gear ratio is fixed, and said control apparatus comprising: an operating condition specifying device that specifies an operating condition of the power element, including a torque of at least one of the rotating electrical machine and the internal combustion engine; and a judging device that judges whether or not there is a drag torque in the locking mechanism on the basis of the specified operating condition.