Abstract: A powertrain includes an engine with an engine output member and a transmission with two motor/generators and a transmission input member operatively connected to the engine output member. A control unit is configured to selectively cause a device to resist or prevent rotation of the input member in response to the existence of certain conditions, such as the engine not supplying torque to the transmission and the transmission being in reverse operating mode. Resisting or preventing rotation of the input member improves transmission performance when only the motor/generators are supplying torque to propel the vehicle. A corresponding method is also provided.

Abstract: A active noise control system having a digital signal processor programmed to function as adaptive digital filter with an output saturation control is described. The programmed adaptive filter has a specified maximum value for its output signal, above which the output signal becomes clipped and a condition commonly known as filter output saturation occurs. According to the described system, the filter output signal value is monitored to detect the occurrence of filter output saturation. When output saturation is detected, the normal adaptation of the filter is modified to reduce the value of the filter output signal to prevent the further occurrence of filter output saturation. Based upon the detection of filter output saturation, a power reference level is established to estimate the maximum average power that the output signal can contain without causing saturation.

Abstract: A method is described for attenuating the amplitudes of multiple harmonic noise components contained within noise generated by an internal combustion engine, based upon the rotation of the engine in its operating cycle. A signal representing selected multiple harmonic noise components is generated from a table of values, based upon the engine rotation. This signal is adaptively filtered to produce a canceling waveform, which is superimposed with the engine noise to attenuate the selected multiple noise harmonics. The method is useful for selecting and attenuating dominant noise harmonics produced at different engine speeds or by different types of engines, and the dominant harmonics of different forms of noise produced by the same engine.