Abstract: An electric machine electrically connects to an inverter via a multi-phase power circuit. A method for monitoring the multi-phase power circuit includes non-intrusively adjusting a commanded AC electric current from the inverter after a prescribed time period and comparing a measured magnitude of AC electric current in the multi-phase power circuit with a minimum threshold. Presence of an open circuit fault in the multi-phase power circuit can be detected based upon the comparison.

Abstract: A powertrain system includes an electric machine mechanically coupled to an internal combustion engine mechanically coupled to a transmission. A method for operating the powertrain system includes determining an engine stall threshold rate during engine operation in a low load condition. A time-rate change in an accessory load is controlled by the electric machine operating in an electric power generating mode in response to the engine stall threshold rate during the engine operation in the low load condition.

Abstract: A method controls an amount of time required to commence transmitting torque of an internal combustion engine equipped with a stop/start feature to a transmission configured to transmit the torque of the engine to drive-wheels in a vehicle. The method includes determining whether a start of the engine is likely. The method also includes pre-filling with fluid a hydraulically-actuated clutch that is configured to connect the engine to the transmission when the start of the engine is likely. Accordingly, the amount of time required to commence transmitting torque of the engine to the transmission is reduced. A system employs the method for controlling an amount of time required to commence transmitting torque of the engine.

Abstract: A powertrain system includes an electric machine mechanically coupled to an internal combustion engine mechanically coupled to a transmission. A method for operating the powertrain system includes determining an engine stall threshold rate during engine operation in a low load condition. A time-rate change in an accessory load is controlled by the electric machine operating in an electric power generating mode in response to the engine stall threshold rate during the engine operation in the low load condition.

Abstract: The present invention provides an improved method and apparatus for regulating active damping in a hybrid vehicle powertrain. The method includes: monitoring the damping command sent to the active damping system; determining a mean reference point, which may be a filtered value of the damping torque command; determining if the unfiltered damping torque command value switches from one side to the other of the mean reference point; if a switch is detected, determining if the size of the switch exceeds a predetermined minimum; if it does, then increasing a total number of switches; determining if the total number of switches exceeds a switch threshold; if the total number of switches exceeds the switch threshold, determining if the current damping torque exceeds a damping torque threshold; and decreasing the damping torque if the total number of switches exceeds the switch threshold and the current damping torque exceeds the damping torque threshold.

Abstract: A method controls an amount of time required to commence transmitting torque of an internal combustion engine equipped with a stop/start feature to a transmission configured to transmit the torque of the engine to drive-wheels in a vehicle. The method includes determining whether a start of the engine is likely. The method also includes pre-filling with fluid a hydraulically-actuated clutch that is configured to connect the engine to the transmission when the start of the engine is likely. Accordingly, the amount of time required to commence transmitting torque of the engine to the transmission is reduced. A system employs the method for controlling an amount of time required to commence transmitting torque of the engine.

Abstract: The present invention provides an improved method and apparatus for regulating state variable estimators used in a hybrid active damping system for a vehicle powertrain. The state estimator provides variable estimates for operating states, such as real-time torque values of axles and dampers, that are not readily measurable with production powertrain and driveline hardware. This facilitates implementation of other control algorithms, such as torque oscillation damping control schemes which use multivariable feedback. The apparatus and method monitors the operating mode of the powertrain, and resets the state estimator for the hybrid active damping ring (HADR) under predetermined operating conditions. For instance, the state estimator includes an array of current state and predicted state variables that are set equal to corresponding reference values or measured values if the powertrain enters into four-wheel drive low (4WDLO).

Abstract: An improved method and apparatus for estimating driveline lash in a vehicle powertrain is provided herein. The method includes: determining if the powertrain is transitioning through driveline lash, e.g., driver commanded torque value changes sign, and then stays between a minimum and maximum commanded torque threshold for a calibrated time; if the powertrain is transitioning through driveline lash, determining when the driveline lash is taken up, e.g., when the transmission output acceleration exceeds a threshold minimum output acceleration, and thereafter changes sign; determining when the estimated lash state changes from neutral to a positive or negative state, which may be inferred from the axle torque estimate behavior; determining the time difference between when the driveline lash is taken up and when the estimated lash state changes from neutral to a positive or negative state; and updating the adaptive lash estimate if the aforementioned time difference is not equal to zero.

Abstract: The present invention provides an improved method and apparatus for regulating state variable estimators used in a hybrid active damping system for a vehicle powertrain. The state estimator provides variable estimates for operating states, such as real-time torque values of axles and dampers, that are not readily measurable with production powertrain and driveline hardware. This facilitates implementation of other control algorithms, such as torque oscillation damping control schemes which use multivariable feedback. The apparatus and method monitors the operating mode of the powertrain, and resets the state estimator for the hybrid active damping ring (HADR) under predetermined operating conditions. For instance, the state estimator includes an array of current state and predicted state variables that are set equal to corresponding reference values or measured values if the powertrain enters into four-wheel drive low (4WDLO).

Abstract: An improved method and apparatus for estimating driveline lash in a vehicle powertrain is provided herein. The method includes: determining if the powertrain is transitioning through driveline lash, e.g., driver commanded torque value changes sign, and then stays between a minimum and maximum commanded torque threshold for a calibrated time; if the powertrain is transitioning through driveline lash, determining when the driveline lash is taken up, e.g., when the transmission output acceleration exceeds a threshold minimum output acceleration, and thereafter changes sign; determining when the estimated lash state changes from neutral to a positive or negative state, which may be inferred from the axle torque estimate behavior; determining the time difference between when the driveline lash is taken up and when the estimated lash state changes from neutral to a positive or negative state; and updating the adaptive lash estimate if the aforementioned time difference is not equal to zero.

Abstract: The present invention provides an improved method and apparatus for regulating active damping in a hybrid vehicle powertrain. The method includes: monitoring the damping command sent to the active damping system; determining a mean reference point, which may be a filtered value of the damping torque command; determining if the unfiltered damping torque command value switches from one side to the other of the mean reference point; if a switch is detected, determining if the size of the switch exceeds a predetermined minimum; if it does, then increasing a total number of switches; determining if the total number of switches exceeds a switch threshold; if the total number of switches exceeds the switch threshold, determining if the current damping torque exceeds a damping torque threshold; and decreasing the damping torque if the total number of switches exceeds the switch threshold and the current damping torque exceeds the damping torque threshold.