Engine torque smoothing

Patent metadata

Field	Value
Publication number	US-10787979-B2
Application number	US-201916278075-A
Country	US
Kind code	B2
Filing date	Feb 16, 2019
Priority date	Jan 12, 2015
Publication date	Sep 29, 2020
Grant date	Sep 29, 2020

Abstract

Methods, devices, estimators, controllers and algorithms are described for estimating the torque profile of an engine and/or for controlling torque applied to a powertrain by one or more devices other than the engine itself to manage the net torque applied by the engine and other device(s) in manners that reduce undesirable NVH. The described approaches are particularly well suitable for use in hybrid vehicles in which the engine is operated in a skip fire or other dynamic firing level modulation manner—however they may be used in a variety of other circumstances as well. In some embodiments, the hybrid vehicle includes a motor/generator that applies the smoothing torque.

First claim

The invention claimed is:

1. A method of operating a vehicle having an internal combustion engine and an additional power source/sink, the engine having working chambers capable of activation and deactivation and the outputs of the engine and additional power source/sink being combined in a powertrain, the method comprising, during operation of the engine:
deactivating, in a cylinder deactivation mode, all of the working chambers in response to a no engine torque request such that none of the working chambers are fired and no air is pumped through the working chambers as the crankshaft rotates;
receiving a torque request;
determining an engine torque profile based on the torque request; and
determining a smoothing torque to be applied by the additional power source/sink that is combined with the engine torque in the vehicle powertrain to deliver the requested torque and maintain acceptable NVH performance during activation of at least one of the engine working chambers, the smoothing torque determined at least partially to compensate for a torque surge caused by an increase in Manifold Absolute Pressure (MAP) during the cylinder deactivation mode; and
applying the smoothing torque in conjunction with the activation of the at least one of the engine working chambers as the internal combustion engine exits the cylinder deactivation mode.

2. The method as recited in claim 1 , wherein generating the smoothing torque further comprises filtering the engine torque profile.

3. The method as recited in claim 1 , wherein the vehicle is a hybrid vehicle and the additional power source/sink is a motor/generator.

4. The method as recited in claim 1 , wherein the additional power source/sink is an alternator that serves as a power sink.

5. The method as recited in claim 1 , wherein the additional power source/sink is an air conditioning unit that serves as a power sink.

6. The method as recited in claim 1 , wherein the smoothing torque is arranged to cause a predicted net powertrain torque to not exceed a threshold instantaneous torque throughout the activation of the at least one of the engine working chambers.

7. The method as recited in claim 1 , wherein the increase in Manifold Absolute Pressure results in the MAP being at atmospheric pressure prior to the exit from the cylinder deactivation mode.

8. The method as recited in claim 1 , wherein the engine is a spark-ignition engine and a spark timing of the at least one activated engine working chamber is adjusted for optimum fuel efficiency.

9. A method of reducing a powertrain torque surge when exiting a DCCO event in a hybrid vehicle having an internal combustion engine and an additional power source/sink both connected to the powertrain comprising:
determining a predicted engine torque surge for the DCCO event exit, the engine torque surge caused at least partially by an increase in Manifold Absolute Pressure (MAP) resulting from no air being pumped through all of the working chambers of the internal combustion engine during the DCCO event; and
applying a smoothing torque from the additional power source/sink to remove torque from a powertrain during the DCCO exit to at least partially counteract the predicted engine torque surge.

10. The method as recited in claim 9 , wherein the smoothing torque is arranged to cause a predicted net powertrain torque to not exceed a threshold instantaneous torque throughout the DCCO event exit.

11. The method as recited in claim 9 , wherein the additional power source/sink is an electric motor/generator.

12. A vehicle control system for directing operation of a vehicle having an internal combustion engine and an additional power source/sink, wherein outputs of the engine and additional power source/sink are combined in a powertrain, the engine having a plurality of working chambers that are capable of activation and deactivation, the vehicle control system comprising:
an engine control unit configured to direct operation of the engine at selected times in a deactivation mode where all of the working chambers are deactivated in response to a no engine torque request such that none of the working chambers are fired and no air is pumped through all of the working chambers as the crankshaft rotates and to direct an exit from the deactivation mode by directing at least one of the working chambers to be activation in response to a torque request received while all of the working chambers are deactivated to thereby generate an engine torque;
a torque profile estimation module configured to determine an engine torque profile reflective of the engine torque generated by the activation of the at least one of the working chambers; and
an additional power source/sink controller configured to determine a smoothing torque based at least in part on the engine torque profile and to direct the additional power source/sink to apply the smoothing torque to the powertrain in conjunction with the activation of the at least one of the working chambers, wherein the engine torque generated by the activation of the at least one of the working chambers and the smoothing torque combine to deliver the requested torque and to maintain acceptable NVH performance during the activation of at least one of the engine working chambers.

13. The vehicle control system as recited in claim 12 , wherein the vehicle is a hybrid vehicle and the additional power source/sink is a motor/generator.

14. The vehicle control system as recited in claim 12 , wherein the additional power source/sink is an alternator that serves as a power sink.

15. The vehicle control system as recited in claim 12 , wherein the additional power source/sink is an air conditioning unit that serves as a power sink.

16. The vehicle control system as recited in claim 12 , wherein the smoothing torque is arranged to cause a predicted net powertrain torque to not exceed a threshold instantaneous torque throughout the activation of the at least one of the engine working chambers.

17. The vehicle control system as recited in claim 12 , wherein the engine torque profile is at least partially reflective of a torque surge generated by the at least one activation working chamber caused by an increase in Manifold Absolute Pressure (MAP) resulting from no air being pumped through all of the working chambers of the internal combustion engine when all of the working chambers are deactivated.

18. A control system for use in a hybrid vehicle having an internal combustion engine and an additional power source/sink that are each connected to a powertrain, the engine having a plurality of cylinders that are capable of activation and deactivation, the control system being configured to:
determine a predicted engine torque surge associated with exiting an all cylinder cut-off event in which all of the cylinders are deactivated such that none of the cylinders are fired and no air is pumped through the cylinders as the crankshaft continues to rotate; and
direct the additional power source/sink to apply a smoothing torque to the powertrain to remove torque from the powertrain during the all cylinder cut-off exit to at least partially counteract the predicted engine torque surge.

19. The control system as recited in claim 18 , wherein the smoothing torque is arranged to cause a predicted net powertrain torque to not exceed a threshold instantaneous torque throughout the all cylinder cut-off event exit.

20. The control system as recited in claim 18 , wherein the additional power source/sink is an electric motor/generator.

Assignees

• Tula Technology Inc

Inventors

• Pirjaberi Mohammad R
• EISAZADEH-FAR Kian
• Carlson Steven E
• Serrano Louis J

Classifications

• F02D41/0087 Primary

  Selective cylinder activation, i.e. partial cylinder operation (deceleration cut-off F02D41/123) · CPC title

• F02D41/3058

  the engine working with a variable number of cycles · CPC title

• F02D41/1498

  measuring engine roughness · CPC title

• Y02T10/40

  Engine management systems · CPC title

• F02D41/0002

  Controlling intake air · CPC title