Wabco Gmbh & Co Ohg

Zf Meritor, LLC

Gerhard Bockmann

Andreas Bohm

Robert Anthony Sayman

Jon M Huber

James Henry Devore

Non-synchronized, manually shiftable transmissions of modern vehicle types are actuated by means of an automated transmission control, and the driver can optionally select any gear by means of an actuator which is electrically connected to the transmission control device. In general terms, the method of this invention includes the operator generating a signal indicating a desire to shift the transmission. The transmission then automatically begins implementing the shift. If the currently engaged gear is not disengaged within a preselected time period, because the system cannot achieve a break torque condition, for example, the system signals the driver to manually operate the clutch. A visual and audible signal preferably are provided to the driver. Once the driver manually operates the clutch, the system is able to complete the desired shift.

Indicator for a shift by wire vehicle transmission

A method of engaging and disengaging transmission gears in a vehicle is provided. A controller processes an initial torque representing an engine torque and an estimated zero torque representing an estimate of a transmission output shaft torque. The controller also sets a high and low band torque about the estimated zero torque. Once the above torques have been determined, the controller compares the initial torque to the high band torque. If the initial torque is below the high band torque, the controller increases the engine torque to the high band torque. If the initial torque is greater than the high band torque, then no preliminary adjustments to the engine torque need be made. At least one shift valve is energized when the engine torque is equal to or greater than the high band torque. The engine torque is decayed by the controller to the low band torque to facilitate engaging and disengaging transmission gears.

Shift synchronization using decaying torque

A process for the control of non-synchronized, manually shiftable vehicle transmissions which are actuated in vehicles of new construction by means of an automated transmission control system whereby the driver is able to select a desired gear by means of an operating unit which is connected electrically to the transmission control system. When the vehicle is stopped and the clutch is disengaged practice of the invention prevents a situation in which the engagement of a gear is prevented by a tooth-on-tooth position of the transmission claws. The disclosed process makes it possible to engage the selected gear in all operating states of the vehicle in a simple and reliable manner. In this regard, a desired gear is first selected, and the clutch is then disengaged. When a suitable speed of the transmission input is then reached, a gear to be engaged is automatically engaged. Thereby, the engagement of a gear when the vehicle is stopped is systematized and facilitated for the driver. Furthermore the driver need not disengage and then again engage the clutch repeatedly in order to avoid a tooth-on-tooth position. The process is used preferably in utility vehicles.

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Laatzen, Germany

Gerhard Bockmann