Knock determination apparatus and method for engines

• US 7,356,404 B2
• Filed: 09/15/2006
• Issued: 04/08/2008
• Est. Priority Date: 09/16/2005
• Status: Active Grant

• Current Assignee: DENSO Corporation, Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: DENSO Corporation, Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Takemura, Yuichi, Kaneko, Rihito, Kasashima, Kenji
• Primary Examiner(s): Wolfe; Willis R.
• Assistant Examiner(s): Hoang; Johnny H.
• Application Number:
  US11/521,379
• Publication Number:
  US 20070067091A1
• Time in Patent Office: 571 Days
• Field of Search: None
• US Class Current: 701/111
• CPC Class Codes: F02D 35/027 using knock sensors
• CPC Class Codes: F02P 5/152 dependent on pinking detecting or indicating knocks in internal-combustion engines G01L23/22
• CPC Class Codes: G01L 23/225 circuit arrangements therefor

Abstract

In determining a knock of an engine, a vibration intensity is calculated by logarithm-transforming a peak value or an integral value of an output signal of a knock sensor. Further, a central value VMED of a vibration intensity distribution is calculated, and also a standard deviation σ in a region where the vibration intensity is smaller than this central value VMED is calculated. A vibration intensity reference value VIB is calculated as VMED−u×σ, thereby setting the vibration intensity reference value VIB to be close to a minimum of the vibration intensity distribution. Further, a knock reference value KCK is set by adding a predetermined value K to the vibration intensity reference value VIB. The vibration intensity detected by the knock sensor is compared with the knock reference value KCK to determine presence/absence of a knocking.

Claims

1. A knock determination apparatus for an internal combustion engine comprising:

a knock sensor for detecting a knock vibration of the internal combustion engine;

vibration intensity calculating means for calculating a vibration intensity from an output signal of the knock sensor in a predetermined sample cycle during operation of the internal combustion engine;

distribution determining means for statistically processing data of the vibration intensity for determining a vibration intensity distribution;

knock reference value setting means for setting a vibration intensity reference value in a region of the vibration intensity distribution where the vibration intensity is smaller and also a knock reference value by using the vibration intensity reference value as a reference; and

knock determining means for comparing the vibration intensity with the knock reference value for determining presence/absence of a knocking.

2. The knock determination apparatus according to claim 1,

wherein the vibration intensity calculating means calculates the vibration intensity by logarithm-transforming a peak value or an integral value of an output signal of the knock sensor during a predetermined knock determination section.

3. The knock determination apparatus according to claim 1,

wherein the knock reference value setting means calculates a central value of the vibration intensity distribution and a variation index in a region where the vibration intensity is smaller than the central value, and calculates the vibration intensity reference value as:

central value−

(variation index×

constant).

4. The knock determination apparatus according to claim 1,

wherein the knock reference value setting means sets the knock reference value by adding a predetermined value to the vibration intensity reference value or multiplying a predetermined value over the vibration intensity reference value.

5. The knock determination apparatus according to claim 1,

wherein the knock reference value setting part sets the knock reference value by adding a predetermined value to the vibration intensity reference value or multiplying a predetermined value over the vibration intensity reference value.

6. A knock determination apparatus for an internal combustion engine comprising:

a knock sensor that detects a knock vibration of the internal combustion engine;

vibration intensity calculating part that calculates a vibration intensity from an output signal of the knock sensor in a predetermined sample cycle during operation of the internal combustion engine;

distribution determining part that statistically processes data of the vibration intensity for determining a vibration intensity distribution;

knock reference value setting part that sets a vibration intensity reference value in a region of the vibration intensity distribution where the vibration intensity is smaller and also a knock reference value by using the vibration intensity reference value as a reference; and

knock determining part that compares the vibration intensity with the knock reference value for determining presence/absence of a knocking.

7. The knock determination apparatus according to claim 6,

wherein the vibration intensity calculating part calculates the vibration intensity by logarithm-transforming a peak value or an integral value of an output signal of the knock sensor during a predetermined knock determination section.

8. The knock determination apparatus according to claim 6,

wherein the knock reference value setting part calculates a central value of the vibration intensity distribution and a variation index in a region where the vibration intensity is smaller than the central value, and calculates the vibration intensity reference value as:

central value−

(variation index×

constant).