Knock suppressing apparatus for internal combustion engine

• US 5,287,837 A
• Filed: 08/22/1991
• Issued: 02/22/1994
• Est. Priority Date: 08/24/1990
• Status: Expired due to Term

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Iwata, Toshio, Hashimoto, Atsuko
• Primary Examiner(s): Nelli, Raymond A.
• Application Number:
  US07/748,725
• Time in Patent Office: 915 Days
• Field of Search: 123/425, 123/417, 123/422, 123/435, 364/431.08, 364/431.07
• US Class Current: 123/406.29
• CPC Class Codes: F02B 1/04 with fuel-air mixture admission into cylinder
• CPC Class Codes: F02D 41/1497 With detection of the mechanical response of the engine
• CPC Class Codes: F02P 5/152 dependent on pinking detecting or indicating knocks in internal-combustion engines G01L23/22
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

A knock suppressing apparatus for an internal combustion engine includes: a knock sensor for sensing the vibrations of an engine and generating a corresponding output signal; an interface circuit for generating a vibration level based on the output signal of the knock sensor; a noise level detector for generating a noise level based on the vibration level; a memory for storing a basic noise level, a basic threshold level and a correction value in relation to the number of revolutions per minute of the engine; a calculator for updating the correction value based on the noise level, the basic noise level and a current engine operating condition, and generating a corrected threshold for knock determination based on the basic threshold and the updated correction value; a knock determiner for making a comparison between the vibration level and the corrected threshold and generating a knock determination signal if the vibration level exceeds the corrected threshold; and a controller for controlling, based on the knock determination signal from the knock determiner, an engine control parameter in a direction to suppress knocking. A condition determiner may be further provided for determining whether the engine is in a predetermined operating range suitable for updating the correction value. In this case, the calculator updates the correction value and generates the corrected threshold if the engine is in the predetermined operating range.

Claims

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

a knock sensor for sensing the vibrations of an engine and generating a corresponding output signal;

an interface circuit for generating a vibration level based on the output signal of said knock sensor.

a noise level detector for generating a noise level based on the vibration level;

memory means for storing a basic noise level, a basic threshold level and a correction value in relation to the number of revolutions per minute of the engine;

calculating means for updating the correction value based on the noise level, the basic noise level and a current engine operating condition, and generating a corrected threshold for knock determination based on the basic threshold and the updated correction value;

a knock determiner for making a comparison between the vibration level and the corrected threshold and generating a knock determination signal if the vibration level exceeds the corrected threshold; and

a controller for controlling, based on the knock determination signal from said knock determiner, an engine control parameter in a direction to suppress knocking.

2. A knock suppressing apparatus according to claim 1, where said calculating means calculates the corrected knock determination threshold V_TH based on a previous threshold V_THR and the correction value V_G using the following formula:

space="preserve" listing-type="equation">V.sub.TH =V.sub.THR +V.sub.G

where V_G is calculated based on a previous correction value V_G * and a target correction value dV_TH as follows;

space="preserve" listing-type="equation">V.sub.G =(1-k)V.sub.G *+k×

dV.sub.TH

wherein k is a constant which is less than 1 and greater than 0, and the target correction value dV_TH is calculated based on the previous threshold V_THR, a deviation dV_N between the vibration level and the previous threshold, and the corrected threshold V_TH as follows;

space="preserve" listing-type="equation">dV.sub.TH =V.sub.THR ×

dV.sub.N /V.sub.TH

3. A knock suppressing apparatus for an internal combustion engine comprising:

a knock sensor for sensing the vibrations of an engine and generating a corresponding output signal;

an interface circuit for generating a vibration level based on the output signal of said knock sensor.

a noise level detector for generating a noise level based on the vibration level;

memory means for storing a basic noise level, a basic threshold level and a correction value in relation to the number of revolutions per minute of the engine;

a condition determiner for determining whether the engine is in a predetermined operating range suitable for updating the correction value;

calculating means for updating the correction value based on the noise level, the basic noise level and a current engine operating condition, and generating a corrected threshold for knock determination based on the basic threshold and the updated correction value if the engine is in the predetermined operating range;

a knock determiner for making a comparison between the vibration level and the corrected threshold and generating a knock determination signal if the vibration level exceeds the corrected threshold; and

a controller for controlling, based on the knock determination signal from said knock determiner, an engine control parameter in a direction to suppress knocking.