Braking strategy for a hybrid drive of a vehicle
AssigneeRobert Bosch GmbH
InventorsThomas Winter, Jochen Fassnacht, Nicole Weber, Kay Hindorf
Life of this patent
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Abstract
Method for operating a hybrid drive, in particular a parallel hybrid drive, of a vehicle. The parallel hybrid drive includes an internal combustion engine and at least one electric drive, at least one energy storage device, and a vehicle transmission. During deceleration phases in which a torque required on the transmission input side is present, the internal combustion engine is operated either in drag mode or at a minimum drive torque.
Claims14
A method for operating a parallel hybrid drive of a vehicle including an internal combustion engine, at least one electric drive, at least one energy storage device, and a vehicle transmission, the method comprising:
- during a deceleration phase in which a torque required on an input side of the transmission is less than zero, obtaining a value of the torque required;
- and
- based on the obtained value of the torque required, calculating energy costs respectively associated with a first mode combination and a second mode combination, wherein in each mode combination, operating modes are selected for the internal combustion engine and for the at least one electric drive;
- comparing the energy cost of the first mode combination to the energy cost of the second mode combination;
- and
- based on the comparison, selecting either the first mode combination or the second mode combination;
- wherein in the first mode combination, the internal combustion engine is selected to be operated in a drag mode, and wherein in the second mode combination, the internal combustion engine is selected to be operated in a minimum drive torque mode;
- wherein in the first mode combination, the at least one electric drive is selected to be operated in an engine mode in which the at least one electric drive provides a positive torque,
- wherein in the second mode combination, the at least one electric drive is selected to be operated in a generator mode in which the at least one electric drive charges the at least one energy storage device, and
- wherein the comparison is based on C1=EEM,1·CBatt,
- wherein:
- C1:
- cost of drawing energy from the energy storage device;
- EEM,1:
- energy drawn from the electric machine in engine mode;
- CBatt:
- energy cost;
- and of energy fed to the at least one energy storage device based on
- C
- 2
- =
- C
- VB
- -
- E
- EM
- ,
- 2
- ·
- C
- VB
- E
- VB
- ,
- internal
- ,
- and
- wherein:
- C2:
- cost of fed energy;
- EEM,2:
- energy fed to the energy storage device when the electric machine is operated in generator mode;
- CVB:
- drive energy of the internal combustion engine;
- and
- EVB,internal:
- internal energy of the internal combustion engine.
A method for operating a parallel hybrid drive of a vehicle including an internal combustion engine, at least one electric drive, at least one energy storage device, and a vehicle transmission, the method comprising:
- operating the internal combustion engine either in drag mode or at a minimum drive torque during deceleration phases in which a torque required on an input side of the transmission is present,
- wherein a braking strategy implemented within a brake function ascertains a more favorable variant, with regard to energy, of operating the internal combustion engine in drag mode or at the minimum drive torque based on a cost comparison of drawing energy for drag of the internal combustion engine based on:
- C1=EEM,1·CBatt
- wherein
- C1:
- cost of drawing energy from the energy storage device;
- EEM,1:
- energy drawn from the electric machine in engine mode;
- CBatt:
- energy cost;
- and of energy fed to the at least one energy storage device based on
- C
- 2
- =
- C
- VB
- -
- E
- EM
- ,
- 2
- ·
- C
- VB
- E
- VB
- ,
- internal
- wherein
- C2:
- cost of fed energy;
- EEM,2:
- energy fed to the energy storage device when the electric machine is operated in generator mode;
- CVB:
- drive energy of the internal combustion engine;
- and
- EVB,internal:
- internal energy of the internal combustion engine.
A method for operating a parallel hybrid drive of a vehicle including an internal combustion engine, at least one electric drive, at least one energy storage device, and a vehicle transmission, the method comprising:
- during a deceleration phase in which a torque required on an input side of the transmission is less than zero, obtaining a value of the torque required;
- based on the obtained value of the torque required, selecting an operation mode for the internal combustion engine, wherein the selected operation mode is either a drag mode or a minimum drive torque mode;
- wherein the selecting of the operation mode for the internal combustion engine is triggered in response to determining TVB,drag<TGE,gef<0, TVB,drag being the drag torque of the internal combustion engine, and TGE,gef being the torque required on the input side of the transmission;
- and
- implementing a braking strategy by ascertaining a more favorable variant, with regard to energy, of operating the internal combustion engine in the drag mode or at the minimum drive torque mode based on a cost comparison of drawing energy for drag of the internal combustion engine, wherein the comparison is based on:
- C1=EEM,1·CBatt
- wherein:
- C1:
- cost of drawing energy from the energy storage device;
- EEM,1:
- energy drawn from the electric machine in engine mode;
- CBatt:
- energy cost;
- and of energy fed to the at least one energy storage device based on
- C
- 2
- =
- C
- VB
- -
- E
- EM
- ,
- 2
- ·
- C
- VB
- E
- VB
- ,
- internal
- ,
- and
- wherein:
- C2:
- cost of fed energy;
- EEM,2:
- energy fed to the energy storage device when the electric machine is operated in generator mode;
- CVB:
- drive energy of the internal combustion engine;
- and
- EVB,internal:
- internal energy of the internal combustion engine.
Dependencies are inferred from the claim text.