Method and apparatus for detecting discrete levels of detonation in an internal combustion engine

• US 4,829,956 A
• Filed: 11/02/1987
• Issued: 05/16/1989
• Est. Priority Date: 11/02/1987
• Status: Expired due to Term

• Current Assignee: Caterpillar Sarl (Caterpillar Incorporated)
• Original Assignee: Caterpillar Incorporated
• Inventors: Esters, Daniel W., Rehn, Bryce H., Baker, Harold A., Penick, Ronald J.
• Primary Examiner(s): Argenbright, Tony M.
• Assistant Examiner(s): NOT, DEFINED
• Application Number:
  US07/115,285
• Time in Patent Office: 561 Days
• Field of Search: 123/198 D, 123/198 DB, 123/198 DC, 123/425, 73/35
• US Class Current: 123/198.0DB
• CPC Class Codes: F02D 35/027 using knock sensors
• CPC Class Codes: F02D 41/22 Safety or indicating devices for abnormal conditions in air/fuel ratio feedback systems F02D41/1495, in electric control linkage F02D11/107, in purge control systems F02M25/0809
• CPC Class Codes: F02P 11/02 Preventing damage to engines or engine-driven gearing
• CPC Class Codes: F02P 5/045 combined with electronic control of other engine functions, e.g. fuel injection in general F02D37/02
• 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 method detects the magnitude of knock in an internal combustion engine. Each knock is quantified into a discrete level which gives an indication of the operating condition of the engine. The discrete level signals provide information helpful during engine calibration and engine monitoring. After a predetermined number of level signals indicative of preselected magnitudes of knock are received, an engine shutdown signal is delivered which ceases engine operation.

Claims

1. A method of detecting the magnitude of knock in an internal combustion engine having at least one combustion chamber, comprising the steps of:

transmitting a signal responsive to a cavity resonance frequency of said combustion chamber;

processing said transmitted signal to produce a knock signal having a magnitude responsive to the magnitude of knock in at least one combustion chamber;

comparing the magnitude of said knock signal to a first preselected reference;

comparing the magnitude of said knock signal to a second preselected reference;

delivering a level signal indicative of the magnitude of said knock signal in response to a portion of said knock signal exceeding at least one of said preselected references;

counting the number of portions of said knock signal exceeding said first preselected reference;

counting the number of portions of said knock signal exceeding said second preselected reference;

delivering an engine shutdown signal in response to a first predetermined number of portions of said knock signals exceeding the first preselected reference; and

delivering an engine shutdown signal in response to a second predetermined number of portions of said knock signals exceeding the second preselected reference.

2. The method, as set forth in claim 1, further comprising the step of:

displaying a level of knock in response to aid level signal.

3. The method, as set forth in claim 2, wherein said step of displaying includes:

illuminating a selected portion of a display in response to the magnitude of said level signal

4. A method of detecting the magnitude of knock in an internal combustion engine having at least one combustion chamber, comprising the steps of:

transmitting a signal responsive to a cavity resonance frequency of said combustion chamber;

processing said transmitted signal to produce a knock signal having a magnitude responsive to the magnitude of knock in at least one combustion chamber;

counting the number of portions of said knock signal exceeding a first preselected reference;

counting the number of portions of said knock signal exceeding a second preselected reference;

delivering n engine shutdown signal in response to a first predetermined number of portions of said knock signals exceeding the first preselected reference; and

delivering an engine shutdown signal in response to a second predetermined number of portions of said knock signals exceeding the second preselected reference.

5. The method set forth in claim 4, wherein said step of processing includes:

filtering said transmitted signal and delivering a filtered signal having a frequency within a range about said cavity resonance frequency.

6. The method, as set forth in claim 5, wherein said step of processing includes:

demodulating said filtered signal and delivering a knock signal responsive to the magnitude of knock.

7. The method set forth in claim 4, wherein:

said engine shutdown signal is delivered in response a first predetermined number of portions of said knock signal exceeding the first preselected reference in a first predetermined amount of time; and

said engine shutdown signal is delivered in response to a second predetermined number of portions of said knock signal exceeding the second preselected reference in a second predetermined amount of time.

8. A method of delivering a shutdown signal in response to the magnitude and recurrence of knock in an internal combustion engine having at least one combustion chamber, comprising the steps of:

transmitting a signal responsive to a cavity resonance frequency of said combustion chamber;

processing said transmitted signal to produce a knock signal having a magnitude responsive to the magnitude of knock in at least one combustion chamber;

counting the number of portions of said knock signal whose magnitude exceeds a preselected reference; and

delivering an engine shutdown signal in response to the counter number exceeding a preselected number in a predetermined amount of time.

9. An apparatus for delivering a shutdown signal in response to the magnitude and recurrence of knock in an internal combustion engine having at least one combustion chamber, comprising:

means for transmitting a signal responsive to a cavity resonance frequency of the combustion chamber;

means for receiving said transmitted signal and processing the same to produce a knock signal having magnitude responsive to the magnitude of knock in the combustion chamber;

means for counting the number of portions of the knock signal whose magnitude exceeds a preselected reference; and

means for delivering an engine shutdown signal in response to the counted number exceeding a preselected number in a predetermined amount of time.

10. An apparatus for delivering a shutdown signal as set forth in claim 9, in which:

the counting means also counts a second number of portions of the knock signal exceeding a second preselected reference; and

the last-mentioned means delivers an engine shutdown signal in response to the second counted number exceeding a second preselected number in the second predetermined amount of time.

11. An apparatus for delivering a shutdown signal as set forth in claim 10, wherein the means for receiving and processing includes:

means for filtering the transmitted signal and delivering a filtered signal having a frequency within a range about said cavity resonance frequency.

12. An apparatus for delivering a shutdown signal as set forth in claim 11, wherein the means for receiving and processing further includes:

a demodulator for demodulating said filtered signal and delivering a knock signal responsive to the magnitude of knock.

13. An apparatus for detecting the magnitude of knock in an internal combustion engine having at least one combustion chamber, comprising:

means for transmitting a signal responsive to a cavity resonance frequency of the combustion chamber;

means for receiving and processing said transmitted signal to produce a knock signal having a magnitude responsive to the magnitude of knock in the combustion chamber;

means for counting the number of portions of said knock signal exceeding a first preselected reference and for counting the number of portions of said knock signal exceeding a second preselected reference; and

means for delivering an engine shutdown signal in response to a first predetermined number of portions of said knock signals exceeding the first preselected reference, and for delivering an engine shutdown signal in response to a second predetermined number of portions of said knock signals exceeding the second preselected reference.