Motor vehicle drive train comprising a hydrodynamic retarder that can be disengaged, and control method therefor

Abstract

The invention relates to a motor vehicle drive train including a hydrodynamic retarder that comprises a revolving bladed impeller and a stationary or counter-rotating bladed turbine which jointly form a working chamber that can be filled with a working medium to switch on the retarder. The hydrodynamic retarder can be mechanically disengaged from the drive train by a disconnect clutch. The invention is characterized in that a fill level monitoring device detects the current fill level of the working medium in the working chamber, while a disconnect clutch-blocking device is effectively connected in a communicating or mechanical manner to the fill level monitoring device and prevents the disconnect clutch from engaging in accordance with the detected fill level.

Description

technical field [0001] The invention relates to a drive train of a motor vehicle with a hydrodynamic retarder which can be mechanically decoupled from the drive train by means of a separating clutch and a control method thereof. Background technique [0002] For many years, hydrodynamic retarders have been used as wear-free continuous brakes not only in rail vehicles but also in road vehicles, the latter in particular trucks. Despite the undisputed advantages of such a wear-free continuous brake in terms of safety during braking and less wear compared to friction-operated service brakes, the hydrodynamic retarder is The idling loss of time is a point of contention. Although idling losses can be reduced by presetting so-called ventilation baffles or by presetting the rotor (primary wheel) moving away from the stator (secondary wheel) during non-braking operation, the latter measure in particular is usually not sufficient here. Reduce idling loss to almost zero. [0003] On...

AI Technical Summary

Problems solved by technology

However, the following disadvantages arise here: on the one hand, the time for closing the separating clutch increases to the time for filling the hydrodynamic retarder, which prolongs the requirement to activate the hydrodynamic retarder and to provide the necessary braking torque from the hydrodynamic retarder reaction time between

On the other hand, compared to a drive train with a hydrodynamic retarder connected to the drive train without a disengaging clutch, a disengaging clutch in particular configured as a friction clutch may suffer due to high loads, especially when the hydrodynamic retarder is switched on. deactivated, resulting in an earlier need for service or replacement parts

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