Drivetrain and method for providing a supply to a compressed air system

Abstract

The invention relates to a drivetrain, in particular motor vehicle drivetrain, with a combustion engine having a drive output shaft and which produces a hot exhaust-gas flow; with a turbocompound system comprising: an exhaust-gas turbine which is arranged in the exhaust-gas flow such that it can be impinged upon by exhaust gas and which converts exhaust-gas energy into propulsive energy, wherein the exhaust-gas turbine is drive-connected, or can be switched so as to be drive-connected, to the output shaft of the internal combustion engine and also drives a turbocompressor or positive-displacement compressor by means of which the internal combustion engine is charged on the fresh-air side; with a compressed air system, comprising: an air compressor which can be driven by means of the combustion engine or an additional motor and which feeds compressed air into at least one compressed-air circuit or a compressed-air line. The invention is characterised by the fact that the air compressor can be charged by means of the turbocompressor or positive-displacement compressor of the turbocompound system, wherein air compressed by the turbocompressor or positive-displacement compressor is supplied to the air compressor on its intake side.

1 . Drivetrain, in particular motor vehicle drivetrain,
 having a combustion engine having a drive shaft and generating a hot exhaust gas stream;   having a turbocompound system comprising:
 an exhaust gas turbine, arranged in the exhaust gas stream to be impinged upon by exhaust gas and converting exhaust energy into drive energy, with the exhaust gas turbine drive-connected via a hydrodynamic coupling to the drive shaft of the combustion engine or able to be switched into one and also driving a turbocompressor or displacement compressor by means of which the combustion engine is supercharged on the fresh air side; 
   having a compressed air system comprising:
 an air compressor, which can be driven by means of a combustion engine or an additional engine and which feeds its compressed air into at least one compressed air circuit or into a compressed air line; wherein 
   the air compressor can be supercharged by means of the turbocompressor or displacement compressor of the turbocompound system, with the air compressed by the turbocompressor or displacement compressor being supplied to the air compressor on the intake side.   
     
     
         2 . Drivetrain according to  claim 1 , wherein the air compressor is developed as a piston-type compressor. 
     
     
         3 . Drivetrain according to  claim 1 , wherein the compressed air system is provided with a compressed air reservoir into which the air compressor conveys compressed air and provision is made in particular for a plurality of different compressed air circuits, with at least one compressed air circuit being developed as a compressed air brake circuit for vehicle brakes. 
     
     
         4 . Drivetrain according to  claim 1 , wherein the air compressor is drive-connected to the drive shaft of the combustion engine or can be switched into one and can be motor driven to feed drive output. 
     
     
         5 . Drivetrain according to  claim 1 , wherein provision is made for a connecting line for compressed air between the compressed air system, in particular its compressed air reservoir, and the fresh air side of the combustion engine, through which compressed air from the compressed air system can be selectively conveyed to the fresh air side of the combustion engine for supercharging. 
     
     
         6 . Drivetrain according to  claim 1 , wherein in addition to the turbocompound system provision is made for a turbocharger, comprising a turbocharger turbine in the exhaust gas stream of the combustion engine, in particular in the direction of flow of the exhaust gas upstream from the exhaust turbine of the turbocompound system, and a turbocharger compressor in a fresh air stream conveyed to the combustion engine, in particular in the direction of flow of fresh air downstream from the turbocompressor or the displacement compressor of the turbocompound system, with the turbocharger compressor being driven by the turbocharger turbine, in particular arranged non-rotatably on a common shaft. 
     
     
         7 . Drivetrain according to  claim 6 , wherein the air compressor can be charged by means of the turbocompressor or the displacement compressor of the turbocompound system and of the turbocharger compressor, with an intercooler line, in particular that branches off from the fresh air stream in the direction of flow after the two compressors—turbocompressor/turbocharger compressor and turbocharger compressor—and discharges on the intake side of the air compressor. 
     
     
         8 . Method for supplying a compressed air system, in particular a motor vehicle compressed air system, involving the following steps:
 an air compressor is driven by means of a combustion engine that generates an exhaust gas stream or by means of a motor for which additional provision is made;   the air is compressed by means of an air compressor and fed into at least one compressed air circuit and/or one compressed air line;   a turbocompressor or displacement compressor is driven by means of an exhaust turbine arranged in the exhaust gas stream, with said turbocompressor or displacement compressor conveying fresh air to the combustion engine on the fresh air side;   compressed fresh air is supplied to the air compressor on the intake side by means of the turbocompressor or the displacement compressor; wherein   in operational states where the exhaust gas stream being fed into the exhaust turbine has a comparatively low energy content, the exhaust turbine and/or the turbocompressor or displacement compressor is driven.   
     
     
         9 . Method according to  claim 8 , wherein the exhaust turbine and/or turbocompressor or displacement compressor is driven by means of a drive connection from a drive shaft of the combustion engine via a hydrodynamic coupling to a shaft bearing the exhaust turbine and/or the turbocompressor. 
     
     
         10 . Drivetrain according to  claim 2 , wherein the compressed air system is provided with a compressed air reservoir into which the air compressor conveys compressed air and provision is made in particular for a plurality of different compressed air circuits, with at least one compressed air circuit being developed as a compressed air brake circuit for vehicle brakes. 
     
     
         11 . Drivetrain according to  claim 2 , wherein the air compressor is drive-connected to the drive shaft of the combustion engine or can be switched into one and can be motor driven to feed drive output. 
     
     
         12 . Drivetrain according to  claim 3 , wherein the air compressor is drive-connected to the drive shaft of the combustion engine or can be switched into one and can be motor driven to feed drive output. 
     
     
         13 . Drivetrain according to  claim 2 , wherein provision is made for a connecting line for compressed air between the compressed air system, in particular its compressed air reservoir, and the fresh air side of the combustion engine, through which compressed air from the compressed air system can be selectively conveyed to the fresh air side of the combustion engine for supercharging. 
     
     
         14 . Drivetrain according to  claim 3 , wherein provision is made for a connecting line for compressed air between the compressed air system, in particular its compressed air reservoir, and the fresh air side of the combustion engine, through which compressed air from the compressed air system can be selectively conveyed to the fresh air side of the combustion engine for supercharging. 
     
     
         15 . Drivetrain according to  claim 4 , wherein provision is made for a connecting line for compressed air between the compressed air system, in particular its compressed air reservoir, and the fresh air side of the combustion engine, through which compressed air from the compressed air system can be selectively conveyed to the fresh air side of the combustion engine for supercharging. 
     
     
         16 . Drivetrain according to  claim 2 , wherein in addition to the turbocompound system provision is made for a turbocharger, comprising a turbocharger turbine in the exhaust gas stream of the combustion engine, in particular in the direction of flow of the exhaust gas upstream from the exhaust turbine of the turbocompound system, and a turbocharger compressor in a fresh air stream conveyed to the combustion engine, in particular in the direction of flow of fresh air downstream from the turbocompressor or the displacement compressor of the turbocompound system, with the turbocharger compressor being driven by the turbocharger turbine, in particular arranged non-rotatably on a common shaft. 
     
     
         17 . Drivetrain according to  claim 3 , wherein in addition to the turbocompound system provision is made for a turbocharger, comprising a turbocharger turbine in the exhaust gas stream of the combustion engine, in particular in the direction of flow of the exhaust gas upstream from the exhaust turbine of the turbocompound system, and a turbocharger compressor in a fresh air stream conveyed to the combustion engine, in particular in the direction of flow of fresh air downstream from the turbocompressor or the displacement compressor of the turbocompound system, with the turbocharger compressor being driven by the turbocharger turbine, in particular arranged non-rotatably on a common shaft. 
     
     
         18 . Drivetrain according to  claim 4 , wherein in addition to the turbocompound system provision is made for a turbocharger, comprising a turbocharger turbine in the exhaust gas stream of the combustion engine, in particular in the direction of flow of the exhaust gas upstream from the exhaust turbine of the turbocompound system, and a turbocharger compressor in a fresh air stream conveyed to the combustion engine, in particular in the direction of flow of fresh air downstream from the turbocompressor or the displacement compressor of the turbocompound system, with the turbocharger compressor being driven by the turbocharger turbine, in particular arranged non-rotatably on a common shaft. 
     
     
         19 . Drivetrain according to  claim 5 , wherein in addition to the turbocompound system provision is made for a turbocharger, comprising a turbocharger turbine in the exhaust gas stream of the combustion engine, in particular in the direction of flow of the exhaust gas upstream from the exhaust turbine of the turbocompound system, and a turbocharger compressor in a fresh air stream conveyed to the combustion engine, in particular in the direction of flow of fresh air downstream from the turbocompressor or the displacement compressor of the turbocompound system, with the turbocharger compressor being driven by the turbocharger turbine, in particular arranged non-rotatably on a common shaft.