Controlling automatic gear-changing of an electric gear-change apparatus of a bicycle, the method may involve assigning each of a plurality of gears of the bicycle a predetermined gearing range. Controlling the process may also involve assigning a predetermined lower limit value and a predetermined upper limit value to each gearing range, wherein the upper limit value of a gearing range is in each case larger by a predetermined value than the lower limit value of a next higher gearing range, and the upper limit value of the gearing range and the lower limit value of the next higher gearing range define between them an overlap range. Controlling the process may also involve selecting an engagement of either a gear or a next higher gear in the overlap range depending on a speed profile of the bicycle.

Methods and systems for improving vacuum generation for an engine that may be operated at higher altitudes are presented. In one non-limiting example, a transmission that is mechanically coupled to the engine may be shifted from a gear to neutral in response to an actual total number of times a vehicle brake pedal is applied and partially released while the vehicle is stopped and the brake pedal is applied.

Methods and systems for improving vacuum generation for an engine that may be operated at higher altitudes are presented. In one non-limiting example, a transmission that is mechanically coupled to the engine may be shifted from a gear to neutral in response to an actual total number of times a vehicle brake pedal is applied and partially released while the vehicle is stopped and the brake pedal is applied.

The present invention relates to a control system for a vehicle powertrain (3). The vehicle powertrain (3) includes a transmission (27), a launch control clutch (31), and a transfer case (39) selectively operable in a high range and a low range. The control system includes a monitor (53, 55) for monitoring one or more operating parameters of the launch control clutch (31) and/or the transmission (27). The control system comprises a controller (49) configured, in dependence on said monitoring means determining that said one or more operating parameters are above a predefined operating threshold or outside a predefined operating range, to output a notification to the user to select said low range; and/or to output a transfer case control signal to the transfer case (39) automatically to select said low range.