MAIN PUMP TO AUXILIARY PUMP HAND-OFF STRATEGY IN HYBRID ELECTRIC VEHICLE

摘要

A method and system of reducing an occurrence of hydraulic pressurization loss during the transition from gas-powered engine operation to electric motor operation in a hybrid electric vehicle. The method includes maintaining operation of the gas-powered engine while initiating an auxiliary pump with its associated electric motor. A master timer is initiated. Once the auxiliary pump exceeds a minimum speed threshold, a delay time period is determined during which operation of the auxiliary pump is tested. If the auxiliary pump does not stall during the delay time period and the master timer has not yet expired, the gas-powered engine is allowed to shut-off.