System and method for determining engine knock

• US 10,107,217 B2
• Filed: 02/09/2017
• Issued: 10/23/2018
• Est. Priority Date: 06/09/2016
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Glugla, Chris Paul
• Primary Examiner(s): Kwon, John
• Application Number:
  US15/428,407
• Publication Number:
  US 20170356366A1
• Time in Patent Office: 621 Days
• Field of Search: 12340611, 12340612, 12340623, 12340624, 12340626, 12340634
• CPC Class Codes: F02D 17/02 Cutting-out cutting-out engines in multiple engine arrangements F02D25/04
• CPC Class Codes: F02D 2200/1002 Output torque
• CPC Class Codes: F02D 2200/101 Engine speed
• CPC Class Codes: F02D 35/027 using knock sensors
• CPC Class Codes: F02D 37/02 one of the functions being ignition
• CPC Class Codes: F02D 41/0087 Selective cylinder activation, i.e. partial cylinder operation deceleration cut-off F02D41/123
• CPC Class Codes: F02P 5/045 combined with electronic control of other engine functions, e.g. fuel injection in general F02D37/02
• CPC Class Codes: F02P 5/152 dependent on pinking detecting or indicating knocks in internal-combustion engines G01L23/22
• CPC Class Codes: F02P 5/1528 for turbocompressed engine
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

Systems and methods for detecting and controlling knock in an engine are presented. In one example, engine knock sensors are selected based on whether or not certain cylinders are activated and combusting air and fuel or deactivated and not combusting air and fuel. Output of selected knock sensors is the basis for adjusting engine spark timing.

Claims

1. A method for operating an engine, comprising:

generating a first knock reference value from a knock sensor output provided to a controller during a first cycle of a cylinder when a cylinder'"'"'s valves are active and combustion occurs in the cylinder;

generating a second knock reference value from the knock sensor output provided to the controller during a second cycle of the cylinder when the cylinder'"'"'s valves are not active and combustion does not occur in the cylinder;

judging a presence or absence of knock based on the first knock reference value during a first condition;

judging the presence or absence of knock based on the second knock reference value during a second condition; and

adjusting engine spark timing via the controller based on the presence or absence of knock.

2. The method of claim 1, further comprising generating a third knock reference value from the knock sensor output provided to the controller during a third cycle of the cylinder when at least one of the cylinder'"'"'s valves are active and combustion does not occur in the cylinder, and judging the presence or absence of knock based on the third knock reference value during a third condition.

3. The method of claim 2, where the first condition is combustion in all cylinders of the engine.

4. The method of claim 3, where the second condition is the first knock reference value being greater than a threshold.

5. The method of claim 2, where the third condition is the first knock reference value being greater than a threshold.

6. The method of claim 2, further comprising integrating the knock sensor output and dividing the integrated knock sensor output by the first knock reference value, the second knock reference value, or the third knock reference value.

7. The method of claim 2, further comprising integrating the knock sensor output and dividing the integrated knock sensor output by the first knock reference value, the second knock reference value, or the third knock reference value based on mapped expected knock reference values.

8. The method of claim 7, where the presence of knock is determined via comparing a knock intensity to a threshold value.