System for method for controlling engine knock of a variable displacement engine

Patent metadata

Field	Value
Publication number	US-2017356366-A1
Application number	US-201715428407-A
Country	US
Kind code	A1
Filing date	Feb 9, 2017
Priority date	Jun 9, 2016
Publication date	Dec 14, 2017
Grant date	—

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.

First claim

1 - 20 . (canceled)

21 . A method for operating an engine, comprising:
saving to memory of a controller in response to deactivating one or more engine cylinders, a first knock reference value based on output of a knock sensor while all cylinders of the engine combust air-fuel mixtures in an engine cycle; and adjusting spark timing of the engine via the controller based on the knock reference value.

22 . The method of claim 21 , further comprising judging the presence or absence of knock based on the first knock reference value, and further comprising suspending knock control for deactivated cylinders and providing an indication of deactivated cylinders to a knock controller.

23 . The method of claim 22 , further comprising integrating output of a knock sensor during a predefined engine crankshaft angular range to provide an integrated knock signal.

24 . The method of claim 23 , further comprising dividing the integrated knock signal by the first reference value.

25 . The method of claim 21 , further comprising determining a second knock reference value in response to deactivating a cylinder via holding at least intake valves of the cylinder closed during a cycle of the cylinder.

26 . The method of claim 25 , where the second reference value is an average of a knock sensor output during a predetermined engine crankshaft interval.

27 . 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 the 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 the 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 a controller based on the presence or absence of knock.

28 . The method of claim 27 , 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.

29 . The method of claim 28 , where the first condition is combustion in all cylinders of the engine.

30 . The method of claim 29 , where the second condition is the first knock reference value being greater than a threshold.

31 . The method of claim 28 , where the third condition is the first knock reference value being greater than a threshold.

32 . The method of claim 28 , further comprising integrating the knock sensor output and dividing the integrated knock sensor output by the first knock reference, the second knock reference, or the third knock reference.

33 . The method of claim 28 , further comprising integrating the knock sensor output and dividing the integrated knock sensor output by the first knock reference, the second knock reference, or the third knock reference based on mapped expected knock reference values.

34 . The method of claim 33 , where the presence of knock is determined via comparing a knock intensity to a threshold value.

35 . A vehicle system, comprising:
an engine including one or more cylinder poppet valve deactivating mechanisms and a knock sensor; and a controller including non-transitory executable instructions, which when executed by the controller, cause the controller to select a knock reference value from a first knock reference value and a second knock reference value, divide an integrated output of the knock sensor by the first knock reference value to provide an engine knock indication during a first condition, divide the integrated output of the knock sensor by the second reference value to provide the engine knock indication during a second condition, and adjust engine spark timing in response to the engine knock indication.

36 . The vehicle system of claim 35 , where the second condition is the first reference value greater than a threshold value.

37 . The vehicle system of claim 35 , further comprising additional instructions to divide the integrated output of the knock sensor by the second reference value in response to deactivating one or more valves of a cylinder.

38 . The vehicle system of claim 35 , further comprising additional instructions to divide the integrated output of the knock sensor by a third reference value in response to deactivating fuel flow to a cylinder and flowing air through the cylinder.

39 . The vehicle system of claim 35 , further comprising instructions to filter output of a knock sensor to provide the first knock reference value.

40 . The vehicle system of claim 35 , further comprising additional instructions to save the first knock reference value to memory in response to deactivating one or more cylinders of the engine.

Assignees

• Ford Global Tech Llc

Inventors

• Glugla Chris Paul

Classifications

• F02D37/02

  one of the functions being ignition · CPC title

• F02D35/027

  using knock sensors · CPC title

• F02P5/152

  dependent on pinking (detecting or indicating knocks in internal-combustion engines G01L23/22) · CPC title

• F02D13/06

  Cutting-out cylinders · CPC title

• F02D2200/1002

  Output torque · CPC title