Patent ID: 7079942
Filing Date: 2006-07-18
Classification: B60K,B60W,F02N,Y02T

Abstract:
1. A method for determining an engine smoothness factor in an engine start event for an accelerator-controlled engine in a vehicle having a hybrid powertrain that includes an electric motor, a battery, a generator and transmission torque delivery elements that define, in part, integrated power flow paths to vehicle traction wheels whereby the engine may be turned off during power delivery from the motor, the method comprising the steps of: determining whether the vehicle is in a park mode or a neutral mode and initializing the method by determining a temporary smoothness factor depending on park or neutral selection and setting it to a value corresponding to maximum smoothness if the vehicle is in a park mode or a neutral mode; measuring accelerator position and determining a temporary smoothness factor as a function of accelerator position; measuring battery voltage and determining a temporary smoothness factor as a function of battery voltage; measuring engine coolant temperature and determining a temporary smoothness factor as a function of engine coolant temperature; measuring battery discharge power limit and determining a temporary smoothness factor as a function of the battery discharge power limit; and selecting the determined temporary smoothness factor with a value corresponding to least smoothness when the engine is in a start-up mode.