Process for actuating a transmission mechanism

A process for actuating a transmission mechanism (3) having several shifting elements (A to E), which are acted on by a pressure source (4) with hydraulic fluid for one of engaging and disengaging different transmission steps, and with several electric actuators (7, 8) of a hydraulic system of the transmission mechanism (3) for adjusting actuating pressures for the shifting elements (A to E),

• wherein a current feed to the electric actuators (7, 8) is set from an operating level, at which the electric actuators (7, 8) are each energized with a current value equivalent to an actuating pressure of the shifting elements (A to E) in dependence upon an operating state when there is a request for an engine start/stop function for shutdown of an internal combustion engine (2) of a drive train having a transmission mechanism (3), to a standby level, and, when there is a request for startup of the internal combustion engine (2) by the engine start/stop function, the current feed to the electric actuators (7, 8) is set from the standby level to the operating level, a system pressure in the hydraulic system is zero when the internal combustion engine (2) is shutdown, and a power consumption in the transmission mechanism during the current feed to the electric actuators (7, 8), at the standby level, is lower than at the operating level, the selected standby level corresponds to the operating level provided for implementation of a transmission step when there is a request for shutdown of the internal combustion engine (2) for the current feed to the electric actuators (7, 8).

A process of adjusting hydraulic actuating pressures with electrical actuators, the hydraulic actuating pressures being directed to shifting elements (A to E) for one of engaging and disengaging shifting gear ratios of a transmission mechanism (3), the method comprising the steps of:

• when a request for shutting down an engine is made by an engine start/stop function, adjusting a flow of electrical current to the electrical actuators from an operating level to a standby level with the flow of electrical current at the operating level being related to the hydraulic actuating pressures directed to the shifting elements (A to E) in an operating state;
• when a request for starting the engine is made by the engine start/stop function, adjusting the flow of electrical current to the electrical actuators from the standby level to the operating level;
• when the engine is shut down, reducing the hydraulic actuating pressures directed to the shifting elements (A to E) to zero;
• setting the flow of electrical current to the electrical actuators at the standby level lower than the flow of electrical current to the electrical actuators at the operating level;
• and
• setting the flow of electrical current to the electrical actuators at the standby level to correspond with the flow of electrical current to the electrical actuators at the operating level for one of engaging and disengaging a shifting gear ratio when the request for shutting down the engine (2) is made by the engine start/stop function.