Method for operating a drivetrain of a motor vehicle, and drivetrain module of motor vehicle of said type

Patent metadata

Field	Value
Publication number	US-10309529-B2
Application number	US-201715492576-A
Country	US
Kind code	B2
Filing date	Apr 20, 2017
Priority date	Apr 21, 2016
Publication date	Jun 4, 2019
Grant date	Jun 4, 2019

Abstract

A method for operating a drivetrain of a motor vehicle, includes, when the motor vehicle is at a standstill and upon demand for a drive torque of the motor vehicle, increasing power (25p) supplied to a separate electric pump drive (25) such that a pressure chamber whose pressurization effects a complete closure or lock-up of a launch element (3) is fast charged with hydraulic pressure from a pump (24). The method also includes performing a launch process of the motor vehicle with the drive source (1) and with a closed or locked-up launch element (3) and reducing the power (25p) supplied to the separate electric pump drive (25) after fast charging the pressure chamber. A related drive train module is also provided.

First claim

The invention claimed is:

1. A method for operating a drivetrain of a motor vehicle, the drivetrain comprising at least one transmission ( 2 ) for providing different transmission ratios between a drive shaft ( 21 ) and an output shaft ( 22 ) of the transmission ( 2 ), a drive source ( 1 ) in the form of an electric motor, a launch element ( 3 ) which is hydraulically actuatable or lockable and which is situated in power flow between the drive source ( 1 ) and the output shaft ( 22 ), and a pump ( 24 ) which is operable independently of the drive source ( 1 ) by a separate electric pump drive ( 25 ) and is configured for hydraulic pressure supply to the transmission ( 2 ), the method comprising:
when the motor vehicle is at a standstill, and upon demand for a drive torque of the motor vehicle, increasing power ( 25 p ) supplied to the separate electric pump drive ( 25 ) such that a pressure chamber, whose pressurization effects a complete closure or lock-up of the launch element ( 3 ), is fast charged with hydraulic pressure from the pump ( 24 );
performing a launch process of the motor vehicle with the drive source ( 1 ) and with a closed or locked-up launch element ( 3 ); and
during the launch process, reducing the power ( 25 p ) supplied to the separate electric pump drive ( 25 ) after fast charging the pressure chamber,
wherein an internal combustion engine ( 9 ) of the motor vehicle is off during the launch process.

2. The method of claim 1 , wherein reducing the power ( 25 p ) supplied to the separate electric pump drive ( 25 ) comprises reducing the power ( 25 p ) supplied to the pump drive ( 25 ) to a value which is dependent on a setpoint drive torque.

3. The method of claim 2 , wherein reducing the power ( 25 p ) supplied to the pump drive ( 25 ) comprises reducing the power ( 25 p ) supplied to the separate electric pump drive ( 25 ) in a continuous manner or a stepped manner.

4. The method of claim 1 , wherein reducing the power ( 25 p ) supplied to the separate electric pump drive ( 25 ) comprises reducing the power ( 25 p ) supplied to the separate electric pump drive ( 25 ) after reaching or overshooting a predetermined rotational speed value ( 1 nt ) of the drive source ( 1 ).

5. The method of claim 4 , wherein the predetermined rotational speed value ( 1 nt ) of the drive source ( 1 ) is temperature-dependent.

6. A drivetrain module of a motor vehicle, comprising:
at least one drive source ( 1 ) in the form of an electric machine;
an interface to an internal combustion engine ( 9 ) of the motor vehicle;
a control unit;
a transmission ( 2 ) for providing different transmission ratios between a drive shaft ( 21 ) and an output shaft ( 22 ) of the transmission ( 2 );
a launch element ( 3 ) which is hydraulically actuatable or lockable and which is situated in power flow between the drive source ( 1 ) and the output shaft ( 22 ); and
a pump ( 24 ) which is operable independently of the drive source ( 1 ) by a separate electric pump drive ( 25 ) and is configured for hydraulic pressure supply to the transmission ( 2 ),
wherein the control unit is programmed for
when the motor vehicle is at a standstill, and upon demand for a drive torque of the motor vehicle, increasing power ( 25 p ) supplied to the separate electric pump drive ( 25 ) such that a pressure chamber, whose pressurization effects a complete closure or lock-up of the launch element ( 3 ), is fast charged with hydraulic pressure from the pump ( 24 ),
performing a launch process of the motor vehicle with the drive source ( 1 ) and with a closed or locked-up launch element ( 3 ), and
during the launch process, reducing the power ( 25 p ) supplied to the separate electric pump drive ( 25 ) after fast charging the pressure chamber,
wherein the control unit is programmed such that the internal combustion engine ( 9 ) of the motor vehicle is off during the launch process.

Assignees

• Zahnradfabrik Friedrichshafen

Inventors

• Bühle Felix
• Platzer Falko
• Lemp Thomas

Classifications

• B60Y2300/421

  Control of lock-up type clutches, e.g. in a torque converter · CPC title

• F16H61/143 Primary

  using electric control means · CPC title

• B60K2025/022

  by a mechanical transmission · CPC title

• B60W10/026

  of lock-up clutches · CPC title

• B60Y2300/18025

  Drive off, accelerating from standstill · CPC title