Abstract: A shift by wire vehicle transmission system includes control methods that are especially useful for controlling the transmission under start-from-stop conditions. Since the master clutch must be manually operated under such conditions, the invention includes a method of determining whether the clutch is open or closed. The rotational speed of the engine output shaft is compared to the rotational speed of the transmission input shaft and if the difference between those speeds is greater than a preselected value, the clutch is determined to be open. Another use of the disclosed method is to provide an indication to the driver whether a desired gear has been engaged. A visual or audible signal indicates to the driver that the desired gear is not yet engaged. Once engagement is confirmed, the signal is turned off and the driver knows that the desired shift has been accomplished.

Abstract: A shift by wire vehicle transmission includes control methods for engaging gears after the vehicle has been at rest or coasting. When the vehicle is started from a stop or rest, a default starting gear is automatically selected. The driver can override the default gear and choose to start driving the vehicle in one gear above or below the default starting gear by manipulating a shift lever. Similarly, the driver can override the default starting gear to begin driving the vehicle in reverse. When the vehicle has been coasting, the transmission control unit chooses the next gear based upon a signal that is provided when the driver manipulates the shift lever. Depending on the indicated desire of the driver, the system controller automatically selects a gear depending upon vehicle speed and torque conditions.