Method and system for variable displacement engine knock control

Patent metadata

Field	Value
Publication number	US-2019353131-A1
Application number	US-201815985257-A
Country	US
Kind code	A1
Filing date	May 21, 2018
Priority date	May 21, 2018
Publication date	Nov 21, 2019
Grant date	—

Abstract

Methods and systems are provided for operating a variable displacement engine that includes a knock control system. Engine background noise levels for detecting engine knock may be the basis for determining whether or not the engine is operating in a cylinder deactivation mode. Further, select variable engine displacement modes may be avoided so that engine background noise level changes may be reduced to improve engine knock detection.

First claim

1 . An engine operating method, comprising:
operating a variable displacement engine; changing from a first cylinder firing density to a second cylinder firing density via a controller based on maintaining fuel injector control actions for one or more engine cylinders that are performed during cylinder knock detection windows for active engine cylinders when the variable displacement engine is operated with the first cylinder firing density.

2 . The method of claim 1 , where the second cylinder firing density maintains fuel injector control actions for one or more cylinders that are performed during cylinder knock detection windows for active engine cylinders when an engine is operated with the first cylinder firing density.

3 . The method of claim 1 , where changing from the first cylinder firing density to the second cylinder firing density is further based on a change in vehicle operating conditions.

4 . The method of claim 3 , where the change in vehicle operating conditions includes a change in engine speed or engine load.

5 . The method of claim 1 , further comprising providing an indication of whether or not a fuel injector of the variable displacement engine is activated or deactivated via an engine knock background noise level and a controller; and
adjusting engine operation responsive to the indication via the controller.

6 . The method of claim 1 , where changing from the first cylinder firing density to the second cylinder firing density includes reducing a firing density of the engine.

7 . The method of claim 1 , where changing the from the first cylinder firing density to the second cylinder firing density includes increasing the firing density of the engine.

8 . An engine operating method, comprising:
operating a variable displacement engine; providing an indication of whether or not a fuel injector of the variable displacement engine is activated or deactivated via an engine knock background noise level and a controller; and adjusting engine operation responsive to the indication via the controller.

9 . The method of claim 8 , where adjusting engine operation includes enabling or disabling one or more variable displacement engine operating modes.

10 . The method of claim 8 , where adjusting engine operation includes adjusting engine spark timing and fuel injection amounts.

11 . The method of claim 8 , where the engine knock background noise level is based on output of an engine knock sensor.

12 . The method of claim 8 , further comprising integrating the output of the engine knock sensor to determine the engine knock background noise level and entering or exiting a variable displacement engine cylinder operating mode to urge a change in the engine knock background noise level, and where the indication of whether or not the fuel injector is activated or deactivated is based on the urge to change the engine knock background noise level, and where the urge to change the engine knock background noise level is commanding one or more engine cylinders to activate or deactivate.

13 . The method of claim 8 , further comprising determining the engine knock background noise level via an observer, where the observer provides an output that is dependent on engine speed, fuel injection timing, and fuel injection duration during a cylinder cycle.

14 . The method of claim 13 , where the output of the observer is further dependent on a difference between a filtered integrated knock level change estimate and an integrated knock level change estimate.

15 . The method of claim 8 , further comprising providing notification to vehicle occupants responsive to the indication.

16 . A system for operating an engine, comprising:
a variable displacement engine; and a controller including executable instructions stored in non-transitory memory to operate the variable displacement engine and change from a direct fuel injection only mode to a port fuel injection only mode when changing from operating the variable displacement engine with a first cylinder firing density to operating the variable displacement engine with a second cylinder firing density in the direct fuel injection only mode causes fuel injector control actions for one or more engine cylinders to be performed inside knock detection windows.

17 . The system of claim 16 , further comprising additional instructions to change start of fuel injection timing of direct fuel injectors when changing from the first cylinder firing density to the second cylinder firing density causes fuel injector control actions for one or more engine cylinders that are performed inside cylinder knock detection windows for active engine cylinders to be performed outside the knock detection windows, and where the fuel injector control actions for the one or more engine cylinders is closing fuel injectors.

18 . The system of claim 16 , where the fuel injector control actions are ceasing fuel injection via fuel injectors.

19 . The system of claim 16 , where a first total number of engine cylinders are active when the variable displacement engine is operated with the first cylinder firing density, where a second total number of engine cylinders are active when the variable displacement engine is operated with the second cylinder firing density.

20 . The system of claim 16 , where operating the variable displacement engine with the first cylinder firing density with direct fuel injection only mode causes fuel injector control actions for the one or more engine cylinders to be performed outside the knock detection windows.

Assignees

• Ford Global Tech Llc

Inventors

• Hakeem Mohannad
• Glugla Christopher Paul
• Kindree James Matthew
• Mcquinn Lee B

Classifications

• F02D41/401

  Controlling injection timing (F02D41/402 takes precedence) · CPC title

• F02D2200/101

  Engine speed · CPC title

• F02D37/02

  one of the functions being ignition · CPC title

• F02D35/027

  using knock sensors · CPC title

• F02D41/30

  Controlling fuel injection {(F02D41/182, F02D41/24 take precedence)} · CPC title