Method to allow trickle-charging on a strong hybrid vehicle to balance accessory loads

Patent metadata

Field	Value
Publication number	US-9493063-B2
Application number	US-201414333337-A
Country	US
Kind code	B2
Filing date	Jul 16, 2014
Priority date	Jul 16, 2014
Publication date	Nov 15, 2016
Grant date	Nov 15, 2016

Abstract

A control-module implemented method for controlling a powertrain system comprising an internal combustion engine, at least one electric machine, a high-voltage battery and an electro-mechanical transmission operative to transmit torque to a driveline includes monitoring a state of charge (SOC) of a high-voltage battery configured to provide stored electrical power to a first electric machine, a second electric machine and at least one auxiliary load. A trickle-charging event is enabled only when the SOC of the high-voltage battery is less than a first SOC threshold. The trickle-charging event activates the first clutch coupled to a first planetary gear set. The trickle-charging event further coordinates a torque capacity of the activated first clutch and a charging set of torque commands between the engine, the first electric machine and the second electric machine to establish a net zero output torque condition.

First claim

The invention claimed is:

1. A control module-implemented method for controlling a powertrain system comprising an internal combustion engine, a first electric machine, a second electric machine, a high-voltage battery and an electro-mechanical transmission operative to transmit torque to a driveline, the control module executing the following steps, comprising:
during operation of the transmission in neutral while the engine is on and a first clutch is deactivated , monitoring a state of charge (SOC) of the high-voltage battery configured to provide stored electrical power to the first electric machine, the second electric machine and at least one auxiliary load;
enabling a trickle-charging event only when the SOC of the high-voltage battery is less than a first SOC threshold, comprising:
activating the first clutch coupled to a first planetary gear set, the first planetary gear set comprising a first element, a second element, and a third element; and
coordinating a torque capacity of the activated first clutch and a charging set of torque commands between the engine, the first electric machine and the second electric machine, the charging set of torque commands comprising torque commands for each of the engine, the first electric machine and the second electric machine configured to establish a net zero output torque condition while enabling generation of electrical energy through the first electric machine.

2. The method of claim 1 , further comprising:
deactivating a second clutch decoupling the first element of the first planetary gear set from a first element of a second planetary gear set, the second planetary gear set comprising the first element coupled to the first electric machine, a second element coupled to the second element of the first planetary gear set via a rotating shaft and a third element of the second planetary gear set coupled to the engine.

3. The method of claim 1 wherein the charging set of torque commands further enables generation of electrical energy through said first electric machine for storage within the high-voltage battery upon presence of the activated first clutch.

4. The method of claim 1 wherein the first clutch is a grounding clutch configured to ground the first element of the first planetary gear set when the first clutch is activated, the second element of the first planetary gear set is coupled to an output member that reacts with the driveline and the third element of the first planetary gear set is coupled to the second electric machine.

5. The method of claim 1 wherein the first clutch provides a reactive torque to assist in establishing the net zero output torque condition upon presence of the activated first clutch.

6. The method of claim 1 wherein generation of electrical energy through said first electric machine for storage within the high-voltage battery is not provided upon a presence of the deactivated first clutch prior to enabling the trickle-charging event during operation of the transmission in neutral.

7. The method of claim 1 wherein operation of the transmission in neutral is enabled in response to an operator input.

8. The method of claim 1 wherein coordinating the charging set of torque commands among the engine and said first and second electric machines to establish the net zero output torque condition comprises:
commanding a positive engine torque;
commanding a positive first motor torque from the first electric machine; and
commanding a negative second motor torque from the second electric machine.

9. The method of claim 8 wherein the commanded positive engine torque supports engine operation at a minimum engine speed associated with engine idle operation enabling generation of electrical energy through said first electric machine for storage within the high-voltage battery only upon presence of the activated first clutch.

10. The method of claim 1 , further comprising:
disabling the trickle-charging event when the SOC of the high-voltage battery is at least a second SOC threshold, comprising:
deactivating the first clutch; and
coordinating a non-charging set of torque commands between the engine, the first electric machine and the second electric machine, the non-charging set of torque commands comprising torque commands for each of the engine, the first electric machine and the second electric machine configured to establish the net zero output torque condition while not enabling generation of electrical energy through the first electric machine.

11. The method of claim 10 wherein the second SOC threshold is equal to the first SOC threshold.

12. The method of claim 10 wherein the second SOC threshold is greater than the first SOC threshold.

13. A control-module implemented method for controlling a powertrain system of a vehicle comprising an internal combustion engine, first and second electric machines, a high-voltage battery, an electro-mechanical transmission comprising at least a first and a second planetary gear set configured to transmit torque to a driveline, the control module configured to execute the following steps, comprising:
in response to an operator input selecting neutral operation of the transmission, operating the transmission in neutral without mechanically decoupling the transmission from the driveline comprising:
commanding a net zero output torque from the transmission to the driveline based on balancing a first set of torque commands among each of the engine and the first and second electric machines;
deactivating a first clutch to unground a first element of the first planetary gear set, the first planetary gear set comprising the first element, a second element, and a third element;
deactivating a second clutch decoupling the first element of the first planetary gear set from a first element of the second planetary gear set, the second planetary gear set comprising the first element, a second element and a third element of the second planetary gear set coupled to the engine; and
when a state of charge of the high-voltage battery configured to provide stored electrical power to the first electric machine, the second electric machine and at least one auxiliary load is less than a SOC threshold, enabling a trickle-charging event comprising:
activating the first clutch to ground the first element of the first planetary gear set, and
coordinating a torque capacity of the activated first clutch and a second set of torque commands among each of the engine, the first electric machine and the second electric machine to maintain the net zero output torque from the transmission to the driveline.

14. The method of claim 13 wherein the second set of torque commands further enable generation of electrical energy through said first electric machine for storage within the high-voltage battery upon a presence of the activated first clutch.

15. The method of claim 13 wherein the first set of torque commands do not enable generation of electrical energy through said first electric machine for storage within the high-voltage battery upon a presence of the deactivated first clutch.

16. The method of claim 13 wherein the second clutch remains deactivated during the trickle-charging event.

17. The method of claim 13 wherein the first clutch provides a reactive torque to assist in maintaining the net zero output torque from the transmission to the driveline upon presence of the activated first clutch and the first set of torque commands among the engine and said first electric machine comprises:
commanding a positive engine torque;
commanding a positive first motor torque f

Assignees

• Gm Global Tech Operations Llc

Inventors

• Naqi Syed
• Bowman Shaun C
• Heap Anthony H
• Mcgrogan Sean W

Classifications

• F16H2200/2035

  with two engaging means · CPC title

• F16H2037/102

  the input or output shaft of the transmission is connected or connectable to two or more differentials · CPC title

• F16H2037/0873

  with switching means, e.g. to change ranges · CPC title

• F16H3/728

  with means to change ratio in the mechanical gearing · CPC title

• B60W2510/101

  Transmission neutral state · CPC title