Patent ID: 7757485

Claim:
A motor vehicle drive train, comprising: an internal combustion engine that drives a crankshaft; an exhaust gas turbine that can drive said crankshaft; and a hydrodynamic coupling for selectively coupling said exhaust gas turbine to said crankshaft, said hydrodynamic coupling comprising: a primary impeller driven by said exhaust gas turbine; a secondary impeller, said primary and secondary impeller forming a working chamber that can be filled with working medium, said primary and secondary impellers being mounted in such a way that they can rotate in relation to each other; a first coupling operating mode in which said primary impeller is driven by said exhaust gas turbine and in which said secondary impeller is driven via a flow circulation of said working medium in said working chamber, said primary and secondary impellers rotating at varying revolutions per minute relative to one another and a slip of less than 100% exists in said hydrodynamic coupling; a retarder operating mode in which said primary impeller is locked mechanically against rotation and said secondary impeller is driven by said crankshaft so that a slip of 100% exists in said hydrodynamic coupling; a bearing inserted between said primary and secondary impellers, said bearing absorbing radial forces and/or axial forces between said primary and secondary impellers; and a film of bearing fluid being formed between a plurality of bearing components that move in relation to each other during operation of said hydrodynamic coupling, said film of bearing fluid being subjected to hydrostatic pressure.