Abstract: A parallel hybrid electric vehicle powertrain and control method wherein an internal combustion engine and an electric motor system define a split power operating mode, a generator drive mode and a parallel power mode. Provision is made, when the motor is inoperable, for preventing discharge of a battery in the electric motor system when the battery state-of-charge is low and for delivering power from the battery when the battery state-of-charge is greater than a predetermined value.

Abstract: A method and system of engine start/stop control for a HEV that monitors the battery and requests a specific engine state based on condition of the battery. A battery parameter such as discharge power limit (DPL) or state of charge (SOC) is compared with a set of threshold levels including a MIN level, an ON level, and an OFF level and the result of the comparison provides inputs to a state machine. The state machine includes an ON state, an OFF state and a OPPORTUNISTIC state. The machine transitions between the various states as a function of DPL and SOC relative to the sets of threshold levels.

Abstract: A parallel hybrid electric vehicle powertrain and control method wherein an internal combustion engine and an electric motor system define a split power operating mode, a generator drive mode and a parallel power mode. Provision is made, when the motor is inoperable, for preventing discharge of a battery in the electric motor system when the battery state-of-charge is low and for delivering power from the battery when the battery state-of-charge is greater than a predetermined value.

Abstract: A method and system for controllably transferring energy from a high voltage bus to a low voltage bus in a hybrid electric vehicle. A vehicle system controller controls a DC/DC converter coupled between the high voltage bus and the low voltage bus to control the transfer of energy therebetween.

Abstract: A parallel hybrid electric vehicle powertrain and control method wherein an internal combustion engine and an electric motor system define a split power operating mode, a generator drive mode and a parallel power mode. Provision is made, when the motor is inoperable, for preventing discharge of a battery in the electric motor system when the battery state-of-charge is low and for delivering power from the battery when the battery state-of-charge is greater than a predetermined value.