Hybrid drive system

Abstract

The invention relates to a hybrid drive system comprising an internal combustion engine ( 11 ) which is operated using fuel ( 21 ) from a fuel tank ( 20 ), and comprising a hydraulic machine ( 12 ) which interacts with a hydraulic energy store ( 38 ). In order to provide a hybrid drive system which requires less installation space than conventional hybrid drive systems, the hydraulic machine ( 12 ) is operated with the same fuel ( 21 ) with which the internal combustion engine ( 11 ) is also operated.

1 . A hybrid drive system having an internal combustion engine ( 11 ) which is operated with fuel ( 21 ) from a fuel tank ( 20 ), and having a hydraulic machine ( 12 ) which interacts with a hydraulic energy store ( 38 ), characterized in that the hydraulic machine ( 12 ) is operated with the same fuel ( 21 ) with which the internal combustion engine ( 11 ) is also operated. 
     
     
         2 . The hybrid drive system as claimed in  claim 1 , characterized in that the hydraulic machine ( 12 ) is hydraulically connected to the fuel tank ( 20 ) of the internal combustion engine ( 11 ) and to the hydraulic energy store ( 38 ). 
     
     
         3 . The hybrid drive system as claimed in  claim 2 , characterized in that a pre-delivery pump ( 22 ) is connected between the fuel tank ( 20 ) and the hydraulic machine ( 12 ). 
     
     
         4 . The hybrid drive system as claimed in  claim 1 , characterized in that a control unit ( 35 ) is connected between the hydraulic machine ( 12 ) and the hydraulic energy store ( 38 ). 
     
     
         5 . The hybrid drive system as claimed in  claim 4 , characterized in that the control unit ( 35 ) is hydraulically connected to a clutch ( 14 ) which is connected between the internal combustion engine ( 11 ) and the hydraulic machine ( 12 ). 
     
     
         6 . The hybrid drive system as claimed in  claim 4 , characterized in that the control unit ( 35 ) is hydraulically connected to a hydraulic motor ( 45 ) which is drivingly connected to a fuel high-pressure pump ( 25 ) of a fuel injection system. 
     
     
         7 . The hybrid drive system as claimed in  claim 4 , characterized in that the control unit ( 35 ) is hydraulically connected to one inlet of a fuel high-pressure pump ( 25 ). 
     
     
         8 . The hybrid drive system as claimed in  claim 1 , characterized in that the hydraulic energy store ( 38 ) comprises a gas pressure accumulator which is filled with fuel and which is connected, or can be connected, to the fuel tank ( 20 ). 
     
     
         9 . A method for operating a hybrid drive system having an internal combustion engine ( 11 ) which is operated with fuel ( 21 ) from a fuel tank ( 20 ), and having a hydraulic machine ( 12 ) which interacts with a hydraulic energy store ( 38 ), comprising operating the hydraulic machine ( 12 ) with the same fuel ( 21 ) with which the internal combustion engine ( 11 ) is also operated. 
     
     
         10 . The method for operating a hybrid drive system as claimed in  claim 9 , further comprising supplying a fuel high-pressure pump ( 25 ) of the fuel injection system with fuel as a function of requirements, said fuel being pressurized by the hydraulic machine ( 12 ). 
     
     
         11 . The hybrid drive system as claimed in  claim 1 , wherein the hydraulic machine is driven by the internal combustion engine. 
     
     
         12 . The hybrid drive system as claimed in  claim 1 , wherein in a pump operating mode, the hydraulic machine pumps fuel from the fuel tank to the hydraulic energy store. 
     
     
         13 . The hybrid drive system as claimed in  claim 3 , characterized in that a control unit ( 35 ) is connected between the hydraulic machine ( 12 ) and the hydraulic energy store ( 38 ). 
     
     
         14 . The hybrid drive system as claimed in  claim 13 , characterized in that the control unit ( 35 ) is hydraulically connected to a clutch ( 14 ) which is connected between the internal combustion engine ( 11 ) and the hydraulic machine ( 12 ). 
     
     
         15 . The hybrid drive system as claimed in  claim 14 , characterized in that the control unit ( 35 ) is hydraulically connected to a hydraulic motor ( 45 ) which is drivingly connected to a fuel high-pressure pump ( 25 ) of a fuel injection system. 
     
     
         16 . The hybrid drive system as claimed in  claim 15 , characterized in that the control unit ( 35 ) is hydraulically connected to one inlet of a fuel high-pressure pump ( 25 ). 
     
     
         17 . The hybrid drive system as claimed in  claim 16 , characterized in that the hydraulic energy store ( 38 ) comprises a gas pressure accumulator which is filled with fuel and which is connected, or can be connected, to the fuel tank ( 20 ).