Basic Gear Shifting Method for Automatic Gear Box in Mild-Hybrid Vehicles Using Cost Functions

摘要

An automatic gear box for a conventional vehicle has to handle basically only the same number of operating points as its number of gears [1]. A power request by the driver is followed by a calculation of new and possible operating points for the combustion engine. The operating point with the lowest fuel consumption is chosen. A Mild-Hybrid vehicle has more than one power source. The electric engine could support the combustion engine but also could also act as an additional load. The interaction of the two engines enables many combinations of electrical engine torque and internal combustion engine (ICE) torque. The best gear could only be chosen if the combination of torque with the lowest chemical and electrical energy consumption is found. The calculation necessary to find this combination has to be done for every possible gear. The presented method combines an energy management system (EMS) based on cost functions with a basic gear shift logic.