Method and device for recognizing the knocking of an internal-combustion engine

• US 5,467,638 A
• Filed: 08/04/1994
• Issued: 11/21/1995
• Est. Priority Date: 04/07/1992
• Status: Expired due to Term

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Philipp, Matthias
• Primary Examiner(s): Williams, Hezron E.
• Assistant Examiner(s): Oda, Christine K.
• Application Number:
  US08/284,528
• Time in Patent Office: 474 Days
• Field of Search: 73/35, 364/431.08, 123/425, 123/435
• US Class Current: 73/35.06
• CPC Class Codes: G01L 23/225 circuit arrangements therefor

Abstract

The method of detecting knocking of an internal combustion engine includes generating a sensor signal with a knock sensor provided with the internal combustion engine; digitizing the knock sensor signal to form a digitized signal; high-pass filtering the resulting digitized signal to form a high-frequency signal; counting amplitudes of oscillations the high-frequency signal which are greater than a first threshold value (P1) to form an amplitude count; integrating an absolute value of the high-frequency signal to obtain an integrated signal; comparing the integrated signal to a second threshold value (P2); and generating an output signal indicating that knocking is occurring when the amplitude count is at least one and when the integrated signal is greater than the second threshold value (P2).

Claims

1. Method of detecting knocking of an internal combustion engine, said method comprising the steps of:

a) generating a sensor signal characteristic of said knocking by a knock sensor provided with said internal combustion engine;

b) digitizing said sensor signal generated in step a) to form a digitized signal;

c) high-pass filtering said digitized signal formed in step b) to form a high frequency signal comprising a plurality of oscillations having amplitudes;

d) counting said amplitudes of said oscillations of said high frequency signal greater than a first threshold value (P1) to form an amplitude count;

e) integrating an absolute value of said high-frequency signal to obtain an integrated signal;

f) comparing said integrated signal to a second threshold value (P2); and

g) generating an output signal indicating said knocking is occurring, when said amplitude count is at least one and when said integrated signal is greater than said second threshold value (P2).

2. Method as defined in claim 1, wherein said internal combustion engine is provided with at least one cylinder having an internal pressure and said sensor signal of said knock sensor is proportional to the internal pressure in the at least one cylinder of the internal combustion engine and said first threshold value is a pressure value.

3. Method as defined in claim 2, wherein said second threshold value is an absolute value characteristic of an energy content of said high frequency signal.

4. Method as defined in claim 3, wherein said comparing is performed only during a measurement window defining an operating phase of said internal combustion engine.

5. Method as defined in claim 4, wherein said internal combustion engine has a crankshaft and said measurement window is open when said crankshaft is at a crank angle in a crank angle range of said crankshaft and closed when said crank angle is outside said crank angle range.

6. Method as defined in claim 4, wherein said internal combustion engine has a camshaft and said measurement window is open when said camshaft is at a cam angle in a cam angle range of said camshaft and closed when said cam angle is outside said cam angle range.

7. Device for detecting knocking in an internal combustion engine, said device comprising

a knock sensor for generating a sensor signal characteristic of said knocking in said internal combustion engine;

an analog/digital converter connected to said knock sensor to receive said sensor signal and to generate a digitized signal;

processor means for high pass filtration and analysis of said sensor signal to detect a presence of a knocking condition in said internal combustion engine,

wherein said processor means includes high-pass filter means for high-pass filtration of said digitized signal to form a high frequency signal comprising a plurality of oscillations having amplitudes, means for counting said amplitudes of said oscillations of said high frequency signal greater than a first threshold value (P1) to form an amplitude count;

means for integrating an absolute value of said high-frequency signal to obtain an integrated signal;

means for comparing said integrated signal to a second threshold value (P2); and

means for generating an output signal indicating said knocking is occurring when said amplitude count is at least one and said integrated signal is greater than said second threshold value.

8. Device as defined in claim 7, wherein said knock sensor is a pressure transducer.

9. Device as defined in claim 7, wherein said internal combustion engine includes a crankshaft and further comprising a position transmitter connected to said crankshaft, said position transmitter including means for generating a crankshaft position signal including information regarding an angular position of said crankshaft.

10. Device as defined in claim 7, wherein said internal combustion engine includes a camshaft and further comprising a position transmitter connected to said camshaft, said position transmitter including means for generating a camshaft position signal including information regarding an angular position of said camshaft.