Camshaft phaser control for variable displacement engines

Patent metadata

Field	Value
Publication number	US-10927779-B2
Application number	US-201815899920-A
Country	US
Kind code	B2
Filing date	Feb 20, 2018
Priority date	Feb 20, 2018
Publication date	Feb 23, 2021
Grant date	Feb 23, 2021

Abstract

Methods and systems are provided for controlling camshaft phasers of a variable displacement engine. In one example, the engine includes first and second cylinder banks, with the engine being configured to operate in a rolling variable displacement mode. The camshaft phasers are torque actuated camshaft phasers, and a controller of the engine may adjust operation of camshaft phasers at the first cylinder bank differently than camshaft phasers at the second cylinder bank.

First claim

The invention claimed is:

1. A method, comprising:
controlling phasing of a first camshaft coupled to a first bank of an engine via a first phase timer;
controlling phasing of a second camshaft coupled to a second bank of the engine via a second phase timer; and
correcting the first and second phase timers by first and second corrections, respectively, where each of the first and second corrections are based on an induction ratio of both the first bank and the second bank, with the first correction being different than the second correction.

2. The method of claim 1 , further comprising providing first and second pulse width modulated actuating signals via a controller to the first and second phase timers, respectively, wherein the controlling of phasing provided by the first phase timer is related to a duty cycle of the first pulse width modulated actuating signal, and the controlling of phasing provided by the second phase timer is related to a duty cycle of the second pulse width modulated actuating signal.

3. The method of claim 2 , wherein the first correction is provided by scaling the duty cycle of the first pulse width modulated actuating signal in relation to the induction ratio, and the second correction is provided by scaling the duty cycle of the second pulse width modulated actuating signal in relation to the induction ratio, with the scaling of the duty cycle of the first pulse width modulated actuating signal being different than the scaling of the duty cycle of the second pulse width modulated actuating signal.

4. The method of claim 3 , wherein the scaling of the duty cycle of the first pulse width modulated actuating signal and the scaling of the duty cycle of the second pulse width modulated actuating signal is increased as the induction ratio decreases.

5. The method of claim 3 , wherein the scaling of the duty cycle of the first pulse width modulated actuating signal is based on a first adjustment curve stored in non-transitory memory of an electronic controller of the engine, and the scaling of the duty cycle of the second pulse width modulated actuating signal is based on a different, second adjustment curve stored in the non-transitory memory of the electronic controller.

6. The method of claim 1 , wherein the first and second phase timers are cam torque actuated phase timers.

7. The method of claim 6 , wherein correcting the first phase timer by the first correction includes:
estimating a first amount of torque applied to the first camshaft based on the induction ratio, and providing a first pulse width modulated actuating signal via an electronic controller to the first phase timer based on the first amount of torque; and
wherein correcting the second phase timer by the second correction includes:
estimating a second amount of torque applied to the second camshaft based on the induction ratio, and providing a second pulse width modulated actuating signal via the electronic controller to the second phase timer based on the second amount of torque.

8. The method of claim 1 , wherein the engine is a variable displacement engine having multiple cylinders and the induction ratio is a ratio of activated cylinders of the multiple cylinders to a total number of the multiple cylinders.

9. A method, comprising:
determining which cylinders of a variable displacement engine are activated or deactivated;
controlling phasing and phase rate of a first camshaft coupled to a first bank of the engine via a first phase timer responsive to a first actuating signal;
controlling phasing and phase rate of a second camshaft coupled to a second bank of the engine via a second phase timer responsive to a second actuating signal; and
scaling the first and second actuating signals in relation to a ratio of activated cylinders of the first bank and the second bank to total cylinders of the first bank and the second bank such that a change in phase rate when a portion of the cylinders is deactivated is equal to a change in phase rate when all the cylinders are activated, the scaling of the first actuating signal being different than the scaling of the second actuating signal.

10. The method of claim 9 , wherein the scaling of the first actuating signal is performed by an electronic controller of the engine via a first scaling factor related to the ratio of the activated cylinders of the first bank and the second bank to the total cylinders of the first bank and the second bank, scaling of the second actuating signal is performed by the electronic controller via a second scaling factor related to the ratio of the activated cylinders of the first bank and the second bank to the total cylinders of the first bank and the second bank, and the first scaling factor is different than the second scaling factor even when a total amount of activated cylinders of only the first bank of the engine is equal to a total amount of activated cylinders of only the second bank of the engine.

11. The method of claim 10 , wherein the first scaling factor and the second scaling factor are each adjusted by a same amount based on an operating temperature of the engine.

12. The method of claim 10 , wherein the first scaling factor is a first output of a first function or first look-up table stored in non-transitory memory of the electronic controller, and wherein the second scaling factor is a second output of a different, second function or different, second look-up table stored in the non-transitory memory of the electronic controller.

13. The method of claim 9 , wherein the controlling of the phasing and the phase rate of the first camshaft via the first phase timer includes adjusting a duty cycle of the first phase timer by transmitting the first actuating signal from an electronic controller of the engine to the first phase timer, and wherein the controlling of the phasing and the phase rate of the second camshaft via the second phase timer includes adjusting a duty cycle of the second phase timer by transmitting the second actuating signal from the electronic controller to the second phase timer.

14. The method of claim 13 , wherein the first and second phase timers are cam torque actuated phase timers, with the duty cycle of the first phase timer determining a phase direction of the first camshaft and the duty cycle of the second phase timer determining a phase direction of the second camshaft.

15. The method of claim 9 , further comprising adjusting which cylinders of the engine are activated or deactivated while maintaining the phase rates of the first and second camshafts at equal rates throughout the adjustment.

16. The method of claim 15 , wherein the maintaining of the phase rates of the first and second camshafts at equal rates includes:
responsive to decreasing a number of activated cylinders while adjusting which cylinders of the engine are activated or deactivated, increasing the scaling of the first actuating signal and the scaling of the second actuating signal; and
responsive to increasing the number of activated cylinders while adjusting which cylinders of the engine are activated or deactivated, decreasing the scaling of the first actuating signal and the scaling of the second actuating signal.

17. A system, comprising:
an engine;
a first cylinder bank of the engine having a first plurality of cylinders, the first plurality of cylinders including valves driven by a first camshaft;
a second cylinder bank of the engine having a second plurality of cylinders, the second plurality of cylinders including valves driven by a second camshaft;
a first camshaft phaser coupled to the first

Assignees

• Ford Global Tech Llc

Inventors

• Bonkoski Phillip
• Karnik Amey
• Cunningham William
• Mcconville Gregory
• Ku Kim Hwe

Classifications

• F01L1/34409 Primary

  by torque-responsive means · CPC title

• F01L1/2405

  by means of a hydraulic adjusting device located between the cylinder head and rocker arm · CPC title

• F01L13/0005

  Deactivating valves · CPC title

• F01L2013/001

  Deactivating cylinders · CPC title

• F01L2001/186

  Split rocking arms, e.g. rocker arms having two articulated parts and means for varying the relative position of these parts or for selectively connecting the parts to move in unison · CPC title