KNOCK DETERMINATION APPARATUS FOR INTERNAL COMBUSTION ENGINE

• US 20160123249A1
• Filed: 11/02/2015
• Published: 05/05/2016
• Est. Priority Date: 11/04/2014
• Status: Active Grant

• Current Assignee: Fujitsu Ten Limited (DENSO Corporation), Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Fujitsu Ten Limited (DENSO Corporation), Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: SAKAYANAGI, Yoshihiro, HASHIMOTO, Sumiaki
• Granted Patent: US 9,816,446 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: F02D 2041/1432 the system including a filter, e.g. a low pass or high pass filter
• CPC Class Codes: F02D 35/023 by determining the cylinder pressure
• CPC Class Codes: F02D 35/027 using knock sensors
• CPC Class Codes: F02D 41/2441 characterised by the learning conditions
• CPC Class Codes: F02D 41/2451 characterised by what is learned or calibrated
• CPC Class Codes: G01H 17/00 Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves, not provided for in the preceding groups see provisionally also G01H1/00
• CPC Class Codes: G01L 23/22 for detecting or indicating knocks in internal-combustion engines; Units comprising pressure-sensitive members combined with ignitors for firing internal-combustion engines
• CPC Class Codes: G01L 23/225 circuit arrangements therefor

Abstract

A knock determination apparatus for an internal combustion engine calculates a knock intensity based on an output signal of an in-cylinder pressure sensor in a gate range for knock determination. When the calculated knock intensity is larger than a knock determination threshold value, the knock determination apparatus determines that knock has occurred. Further, the knock determination apparatus calculates an integrated intensity which is an integrated value of knock intensities that are equal to or larger than a knock intensity at a point of 97% or more in a target knock level among knock intensities that are calculated at the respective cycles during continuous N cycles in the same cylinder. Furthermore, the knock determination apparatus corrects a knock determination threshold value so that the difference between the calculated integrated intensity and a target integrated intensity becomes small.

Claims

1. A knock determination apparatus for an internal combustion engine including an in-cylinder pressure sensor that is installed in each cylinder and detects an in-cylinder pressure,

wherein the knock determination apparatus is configured to:

calculate a knock intensity that is a signal intensity in a predetermined frequency band including a knock frequency band, based on an output signal from the in-cylinder pressure sensor in a predetermined crank angle range;

determine that when the knock intensity calculated by the knock determination apparatus is larger than a knock determination threshold value, knock has occurred;

calculate an integrated intensity that is an integrated value of knock intensities that are equal to or larger than a predetermined knock intensity threshold value among knock intensities that are calculated at a respective cycles during a predetermined plurality of cycles in a same cylinder; and

correct the knock determination threshold value so that a difference between the integrated intensity calculated by the knock determination apparatus and a target integrated intensity becomes small,

wherein the predetermined knock intensity threshold value is a knock intensity in a boundary of top predetermined percentage out of knock intensities included in a frequency distribution showing a relation between the knock intensities acquired in the predetermined plurality of cycles when an internal combustion engine is operated in a state in which a knock level specified in accordance with a knock intensity and a knock frequency is a target knock level, and calculation frequencies of a respective knock intensities, and

wherein the target integrated intensity is an integrated value of knock intensities that are equal to or larger than the knock intensity threshold value that are extracted from the knock intensities which are acquired in the predetermined plurality of cycles when the internal combustion engine is operated in the state in which the knock level is the target knock level.

2. The knock determination apparatus according to claim 1,

wherein when the integrated intensity is larger than the target integrated intensity, the knock determination apparatus is configured to make the knock determination threshold value small.

3. The knock determination apparatus according to claim 1,

wherein when the integrated intensity is smaller than the target integrated intensity, the knock determination apparatus is configured to make the knock determination threshold value large.

4. The knock determination apparatus according to claim 1,

wherein the top predetermined percentage is in a range from top 3 percent through top 5 percent.