Patent ID: 8897946

Claim:
A control method of a hybrid vehicle that includes a first planetary gear set having a first sun gear, a first planetary gear, a first ring gear, and a first carrier, a second planetary gear set having a second sun gear, a second planetary gear, a second ring gear, and a second carrier, an engine connected to the first carrier via a first output shaft, a first motor-generator configured to rotate the first ring gear, a second motor-generator connected to the second sun gear to rotate the second sun gear and the first sun gear, a first brake configured to brake the first ring gear, a second brake configured to brake the second ring gear, a first clutch selectively connecting the first ring gear with the first carrier, and a second clutch selectively connecting the first carrier with the second ring gear, the method comprising: controlling, by a control unit installed in the vehicle, the second clutch to be engaged; outputting torque through a second output shaft that is connected to the second carrier, the torque supplied from the engine and the first and second motor-generators; controlling, by the control unit installed in the vehicle, the speed of the engine by using the first motor-generator; and controlling, by the control unit installed in the vehicle, the torque of the second output shaft by using the second motor-generator wherein a rotation speed of the first motor-generator is controlled so that the engine reaches a predetermined target speed, and wherein the predetermined target speed of the engine is calculated by Formula 2 below: ω MG ⁢ ⁢ 1 = 1 + R 1 + R 2 R 1 ⁢ ω ENG - 1 + R 2 R 1 ⁢ ω out , Formula ⁢ ⁢ 2 wherein R 1 corresponds to a gear ratio of a ring gear of a first planetary gear set, R 2 corresponds to a gear ratio of a ring gear of a second planetary gear set, ω out corresponds to an output velocity of the second carrier gear and ω ENG corresponds to an output velocity of the engine.