Method for detecting combustion noise in internal combustion engine, combustion noise detection device, and device for controlling internal combustion engine

Patent metadata

Field	Value
Publication number	US-9494098-B2
Application number	US-201214235271-A
Country	US
Kind code	B2
Filing date	Jul 26, 2012
Priority date	Jul 28, 2011
Publication date	Nov 15, 2016
Grant date	Nov 15, 2016

Abstract

Although a method for changing a combustion method taking place in an internal combustion engine depending on running condition is proposed, it can be considered that conditions under which a combustion noise occurs naturally differ with different methods. A detection method of prior art is not compatible with different combustion methods and the accuracy of combustion noise detection was low. Accurate combustion noise detection is enabled by identifying a combustion mode taking place in the internal combustion engine, selecting a sensed frequency or frequency band of a combustion noise sensor that detects a combustion noise in a combustion chamber of the internal combustion engine according to the combustion mode, and detecting a combustion noise.

First claim

The invention claimed is:

1. A method for controlling an internal combustion engine, comprising detecting a combustion noise in the internal combustion engine for use in a control device that computes a comparative magnitude of a combustion noise by frequency analysis processing on a frequency signal from a combustion noise sensor that detects a combustion noise in a combustion chamber of the internal combustion engine as a frequency output, the method characterized in that the control device
(1) identifies a combustion mode taking place in the combustion chamber, which is set depending on running condition, the combustion mode being set to a mode corresponding to one of spark ignited combustion in which air-fuel mixture is ignited by an ignition plug and compression ignited combustion in which air-fuel mixture or air is compressed by a piston, thus causing self-ignition, and selects a proper sensed frequency of the combustion noise sensor for the combustion mode; and
(2) computes a comparative magnitude of a combustion noise specific to the combustion mode taking place in the combustion chamber by frequency analysis processing on the selected sensed frequency output; and
further comprising controlling combustion by a regulatory means so that an actual combustion noise becomes less than a predetermined value of combustion noise when the computed comparative magnitude of a combustion noise is more than the predetermined value.

2. The method for controlling an internal combustion engine according to claim 1 , characterized in that a sensed frequency of the combustion noise sensor for the compression ignited combustion is set to a lower value than a sensed frequency of the combustion noise sensor for the spark ignited combustion.

3. A method for controlling an internal combustion engine, comprising detecting a combustion noise in the internal combustion engine for use in a control device that computes a comparative magnitude of vibration by frequency analysis processing on a frequency signal from a non-resonant knock sensor that detects vibration caused by combustion in a combustion chamber of the internal combustion engine as a frequency output, the method characterized in that the control device
(1) identifies a combustion mode taking place in the combustion chamber, the combustion mode being set to a mode corresponding to one of spark ignited combustion in which air-fuel mixture is ignited by an ignition plug and compression ignited combustion in which air-fuel mixture or air is compressed by a piston, thus causing self-ignition, which is set depending on running condition, and selects a proper sensed frequency of the knock sensor for the combustion mode; and
(2) computes a comparative magnitude of vibration specific to the combustion mode taking place in the combustion chamber by frequency analysis processing on the selected sensed frequency output; and
further comprising controlling combustion by a regulatory means so that an actual vibration becomes less than a predetermined value of vibration when the computed comparative magnitude of vibration is more than the predetermined value.

4. The method for controlling an internal combustion engine according to claim 3 , characterized in that a sensed frequency of the knock sensor for the compression ignited combustion is set to a lower value than a sensed frequency of the knock sensor for the spark ignited combustion.

5. The method for controlling an internal combustion engine according to claim 4 , characterized in that a sensed frequency band of the knock sensor for the spark ignited combustion is set to a band including sensed frequencies having at least two or more distinct peaks and a sensed frequency band of the knock sensor for the compression ignited combustion is set to a band including a sensed frequency having a single distinct peak.

6. The method for controlling an internal combustion engine according to claim 4 , characterized in that sensed frequency bands of the knock sensor for the spark ignited combustion are set to two or more bands respectively including center frequencies having at least two or more distinct peaks and a sensed frequency band of the knock sensor for the compression ignited combustion is set to a band including a center frequency having a single distinct peak.

7. The method for controlling an internal combustion engine according to claim 1 , characterized in that the combustion mode taking place in the combustion chamber, which is set depending on running condition, is one of the following modes: compression ignited combustion, lean combustion, exhaust gas recirculation combustion, and stoichiometric spark ignited combustion, and a sensed frequency among these modes is lowest in compression ignited combustion, higher in lean combustion, even higher in exhaust gas recirculation combustion, and highest in stoichiometric spark ignited combustion.

8. A device for controlling an internal combustion engine, the device computing a comparative magnitude of a combustion noise by frequency analysis processing on a frequency signal from a combustion noise sensor that detects a combustion noise in a combustion chamber of the internal combustion engine as a frequency output, the device characterized by comprising:
a combustion mode identifying means that identifies a combustion mode taking place in the combustion chamber, the combustion mode being set to a mode corresponding to one of spark ignited combustion in which air-fuel mixture is ignited by an ignition plug and compression ignited combustion in which air-fuel mixture or air is compressed by a piston, thus causing self-ignition, which is set depending on running condition;
a frequency selecting means that selects a sensed frequency of the combustion noise sensor, which has been predetermined to be specific to a combustion mode identified; and
a combustion noise computing unit that computes a comparative magnitude of a combustion noise specific to the combustion mode taking place in the combustion chamber by frequency analysis processing on the selected sensed frequency output; and
a regulating means that, if an output of the combustion noise computing unit is more than a predetermined value of combustion noise, controls combustion so that an actual combustion noise becomes less than the predetermined value of combustion noise by action of the regulatory mechanism.

9. The device for controlling an internal combustion engine according to claim 8 , characterized in that the frequency selecting means selects a sensed frequency predetermined for the spark ignited combustion if the spark ignited combustion is identified and selects a sensed frequency predetermined for the compression ignited combustion, which is lower than the sensed frequency for the spark ignited combustion, if the compression ignited combustion is identified.

10. A device for controlling an internal combustion engine, the device computing a comparative magnitude of vibration by frequency analysis processing on a frequency signal from a non-resonant knock sensor that detects vibration caused by combustion in a combustion chamber of the internal combustion engine as a frequency output, the device characterized by comprising:
a combustion mode identifying means that identifies a combustion mode taking place in the combustion chamber, the combustion mode being set to a mode corresponding to one of spark ignited combustion in which air-fuel mixture is ignited by an ignition plug and compression ignited combustion in which air-fuel mixture or air is compressed by a piston, thus causing self-ignition, which is set depending on running condition;
a frequency selecting means that selects a sensed frequency of the knock sensor, which has been pred

Assignees

• Ogata Kenichiroh
• Watanabe Daisuke
• Okamoto Takashi
• Hitachi Automotive Systems Ltd

Inventors

• Ogata Kenichiroh
• Watanabe Daisuke
• Okamoto Takashi

Classifications

• F02D2041/1432

  the system including a filter, e.g. a low pass or high pass filter · CPC title

• F02D35/027

  using knock sensors · CPC title

• F02D41/1493 Primary

  Details · CPC title

• G01H17/00 Primary

  Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves, not provided for in the other groups of this subclass · CPC title

• G01M15/12

  by monitoring vibrations · CPC title