The powertrain system of an automobile is generally designed to supply a specific level of torque to the wheels of a vehicle even when the vehicle is stopped. This torque, commonly referred to as creep torque, works against the driver's application of the brakes such that the vehicle will begin to move when the brakes are released even if an accelerator is not depressed. However, in some situations, for example, when the vehicle is idling or when the vehicle is traveling downhill, a high level of creep torque is unnecessary and may cause needless consumption of fuel. Thus, there is a need for a transmission control system that can control the level of creep torque supplied by the powertrain to improve fuel economy.
On the other hand, supplying a consistently low level of creep torque or even no creep torque to increase fuel economy may be detrimental to driving performance. For example, supplying a low level of creep torque may cause unwanted rearward rolling when a vehicle is stopped on an uphill incline. Thus, there is also a need for a creep control system that can provide optimized creep performance while minimizing unnecessary fuel consumption.