METHOD FOR OPERATING A DRIVETRAIN

• US 20120158232A1
• Filed: 08/31/2010
• Published: 06/21/2012
• Est. Priority Date: 09/02/2009
• Status: Active Grant

• Current Assignee: ZF Friedrichshafen AG (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: ZF Friedrichshafen AG (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: Amann, Notker, Banerjee, Alexander
• Granted Patent: US 8,527,131 B2
• Time in Patent Office: Days
• US Class Current: 701/22
• CPC Class Codes: B60K 25/00 Auxiliary drives B60K16/00 takes precedence; arrangements of tyre-inflating pumps mounted on vehicles B60C23/10; driving tyre-inflating pumps B60C; driving engine auxiliaries F02B
• CPC Class Codes: B60L 2240/34 Cabin temperature
• CPC Class Codes: B60W 10/10 including control of change-speed gearings
• CPC Class Codes: B60W 10/26 for electrical energy, e.g. batteries or capacitors
• CPC Class Codes: B60W 10/30 including control of auxiliary equipment, e.g. air-conditioning compressors or oil pumps
• CPC Class Codes: B60W 20/00 Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: B60W 30/1888 Control of power take off [PTO]
• CPC Class Codes: B60Y 2400/15 Pneumatic energy storages, e.g. pressure air tanks
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y02T 10/84 Data processing systems or methods, management, administration

Abstract

A method of operating a drive-train of a motor vehicle having a hybrid drive with an internal combustion engine and an electric machine, an electrical energy accumulator that can be charged when the electric machine operates as a generator and discharged when the electric machine operates as a motor, a transmission connected between the hybrid drive and a drive output, and at least one auxiliary power takeoff on either the transmission or the hybrid drive side such that the auxiliary power takeoff can be operated with variable energy demand within functional capability limits that depend on the auxiliary power takeoff. Depending on the current operating status of the hybrid drive unit, the electrical energy accumulator and/or the auxiliary power takeoff, energy available in the drive-train, but not required at the drive output, can bypass the electrical energy accumulator and be stored in the auxiliary power takeoff.

Claims

1-9. -9. (canceled)

10. A method of operating a drive-train of a motor vehicle, the drive-train comprising a drive aggregate having a hybrid drive unit with an internal combustion engine and an electric machine, an electrical energy accumulator that is chargeable when the electric machine of the hybrid drive unit operates as a generator and is dischargeable when the electric machine of the hybrid drive unit operates as a motor, a transmission connected between the hybrid drive unit and a drive output, and at least one auxiliary power takeoff on at least one of a transmission side and a drive aggregate side such that the at least one auxiliary power takeoff operable with variable energy demand within functional capability limits that depend on the auxiliary power takeoff, depending on at least one of a current operating status of the hybrid drive unit, a current operating status of the electrical energy accumulator and a current operating status of the at least one auxiliary power takeoff, the method comprising the steps of:

determining an energy balance for the drive-train as a whole, and

based on the determined energy balance and taking into account an efficiency of the internal combustion engine, the electric machine, the electrical energy accumulator and the at least one auxiliary power takeoff, and a storage capacity and condition parameters of the energy accumulator and functional capability limits of the at least one auxiliary power takeoff, at least one of;

storing energy not required at the drive output in the electrical energy accumulator, and

directing the energy to bypass the electrical energy accumulator and storing the energy in the auxiliary power takeoff to ensure an optimum overall efficiency of the drive-train.

11. The method according to claim 10, further comprising the step of, when the auxiliary power takeoff is a cooling aggregate that cools a refrigeration chamber, the energy not needed at the drive output bypassing the electrical energy accumulator and being used by the cooling aggregate for cooling down the refrigeration chamber to within admissible temperature limits so as to store the energy, not needed at the drive output, as thermal energy in the refrigeration chamber.

12. The method according to claim 10, further comprising the step of when the auxiliary power takeoff is a cooling fan that cools an internal combustion engine, the energy not needed at the drive output bypassing the electrical energy accumulator and being used by the cooling fan for cooling the internal combustion engine to within admissible temperature limits so as to utilize the energy, not needed at the drive output, as thermal energy for cooling the internal combustion engine.

13. The method according to claim 10, further comprising the step of when the auxiliary power takeoff is a heating aggregate that warms up an internal combustion engine, the energy not needed at the drive output bypassing the electrical energy accumulator and being used by the heating aggregate for warming up the internal combustion engine to within admissible temperature limits so as to utilize the energy, not needed at the drive output, as thermal energy for warming up the internal combustion engine.

14. The method according to claim 10, further comprising the step of when the auxiliary power takeoff is an air-conditioning unit that either warms up or cools down a passenger compartment, the energy not needed at the drive output bypassing the electrical energy accumulator and being used by the air-conditioning unit for either warming up or cooling down the passenger compartment to within admissible temperature limits so as to utilize the energy, not needed at the drive output, in the passenger compartment.

15. The method according to claim 10, further comprising the step of when the auxiliary power takeoff is either a hydraulically or a pneumatically actuated auxiliary power takeoff, the energy not needed at the drive output bypassing the electrical energy accumulator and being used to increase a working pressure to within admissible pressure limits in either a hydraulic reservoir or a pneumatic reservoir.

16. The method according to claim 10, further comprising the step of increasing a load operating point of the internal combustion engine based of the energy balance.

17. The method according to claim 16, further comprising the step of, at high driving speeds within the functional capability limits of the auxiliary power takeoff, preventing supply of further energy to the auxiliary power takeoff concerned based on the energy balance.

18. A method for operating a drive-train of a motor vehicle, the drive-train comprising a hybrid drive unit with an internal combustion engine and an electric machine, an electrical energy accumulator that is chargeable when the electric machine operates as a generator and dischargeable when the electric machine operates as a motor, a transmission that is connected between the hybrid drive unit and a drive output, and at least one auxiliary power takeoff connected to at least one of the transmission and the hybrid drive, the at least one auxiliary power takeoff is operated with a variable energy demand within functional capability limits that depend on the auxiliary power takeoff, depending on a current operating status of at least one of the hybrid drive unit, the electrical energy accumulator and the at least one auxiliary power takeoff, the method comprising the steps of:

determining an energy balance for the drive-train as a whole;

at least one of storing energy that is not required at the drive output in the electrical energy accumulator and directing the energy that is not required at the drive output to bypass the electrical energy accumulator and storing the energy that is not required at the drive output in the auxiliary power takeoff, based on the determined energy balance and at least one of an efficiency of the internal combustion engine, an efficiency of the electric machine, an efficiency of the electrical energy accumulator, an efficiency of the at least one auxiliary power takeoff, and storage capacity and condition parameters of the energy accumulator and functional capability limits of the at least one auxiliary power takeoff.