Systems and methods for operating a hybrid powertrain that includes an engine and a motor/generator are described. The systems and methods adjust torque converter clutch opening responsive to whether or not a motor/generator is available to provide a negative torque to a driveline. Further, the motor/generator and the vehicle's engine are operated to provide a desired amount of driveline braking.

A hybrid vehicle having a pendulum damper in which resonance at around an idling speed of an engine can be prevented to improve N.V. performance. The hybrid vehicle comprises an engine and at least one motor. In the hybrid vehicle, a power transmission path is formed between the engine and drive wheels. In the power transmission path, a pendulum damper is disposed to suppress torsional vibrations, and a disconnecting clutch is disposed to selectively interrupt power transmission between the engine and the pendulum damper.

A hybrid vehicle having a pendulum damper in which resonance at around an idling speed of an engine can be prevented to improve N.V. performance. The hybrid vehicle comprises an engine and at least one motor. In the hybrid vehicle, a power transmission path is formed between the engine and drive wheels. In the power transmission path, a pendulum damper is disposed to suppress torsional vibrations, and a disconnecting clutch is disposed to selectively interrupt power transmission between the engine and the pendulum damper.

Systems and methods for operating a hybrid powertrain that includes an engine and a motor/generator are described. The systems and methods adjust torque converter clutch opening responsive to whether or not a motor/generator is available to provide a negative torque to a driveline. Further, the motor/generator and the vehicle's engine are operated to provide a desired amount of driveline braking.

A method for calibrating the feedback gains of an LQI controller implemented in an electronic control unit operatively connected for controlling operation of a physical electric or electro-mechanical device of a dynamic physical system, in particular a vehicle powertrain, wherein the method of calibrating the LQI controller includes: obtaining values of various physical parameters of the dynamic physical system; inserting the obtained values of the physical parameters into predetermined equations for calculating numerical values of the individual terms of a P matrix, wherein the P matrix is the solution to the Algebraic Riccati equation, and wherein said equations include the physical parameters of the system; and calculating new feedback gains for the LQI controller based on the matrix equation

[00001]$K=r^{-1}{B}_{\mathrm{aug}}^{T}P,$

based on an arbitrarily chosen positive value of r, wherein the terms of the K matrix corresponds to the feedback gains.