System and method for controlling ignition timing to suppress engine knocking using periodic pseudo random signal
First Claim
1. A system for controlling ignition timing for an internal combustion engine, comprising:
- a) first means for detecting an engine revolution speed and an engine load;
b) second means for calculating a basic ignition timing value on the basis of the detected engine revolution speed and engine load;
c) third means for generating an ignition signal at a timing calculated by the second means and igniting air-fuel mixture supplied to the engine in response to the ignition signal;
d) fourth means for generating a periodic pseudo random signal;
e) fifth means for superimposing the periodic pseudo random signal on the ignition signal;
f) sixth means for detecting engine knocking and outputting an engine knocking level signal which changes due to the superimposition of the periodic pseudo random signal;
g) seventh means for calculating a cross-correlation function of both the knocking level signal and pseudo random signal;
h) eighth means for determining whether the cross-correlation function coincides with a predetermined target value;
i) ninth means for calculating an advance/retardation correction coefficient of the ignition timing so that the cross-correlation function coincides with the predetermined target value; and
j) tenth means for correcting the basic ignition timing value according to the calculated advance/retardation correction coefficient and determining an output ignition timing value.
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Accused Products
Abstract
A system and method for controlling ignition timing for an internal combustion engine to suppress engine knocking in which a periodic pseudo random signal (for example, M-series sequence signal) is superimposed on an ignition signal provided at an ignition timing, and a cross-correlation function between the periodic pseudo random signal χ and a knocking signal y is calculated to determine an actual knocking level. The ignition timing is then corrected so that the cross-correlation function coincides with a target value which is defined as a value placed in a vicinity of a knocking limit. The ignition timing for the engine is controlled so as to reach the value in the vicinity of the knocking limit but does not exceed the knocking limit.
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Citations
12 Claims
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1. A system for controlling ignition timing for an internal combustion engine, comprising:
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a) first means for detecting an engine revolution speed and an engine load; b) second means for calculating a basic ignition timing value on the basis of the detected engine revolution speed and engine load; c) third means for generating an ignition signal at a timing calculated by the second means and igniting air-fuel mixture supplied to the engine in response to the ignition signal; d) fourth means for generating a periodic pseudo random signal; e) fifth means for superimposing the periodic pseudo random signal on the ignition signal; f) sixth means for detecting engine knocking and outputting an engine knocking level signal which changes due to the superimposition of the periodic pseudo random signal; g) seventh means for calculating a cross-correlation function of both the knocking level signal and pseudo random signal; h) eighth means for determining whether the cross-correlation function coincides with a predetermined target value; i) ninth means for calculating an advance/retardation correction coefficient of the ignition timing so that the cross-correlation function coincides with the predetermined target value; and j) tenth means for correcting the basic ignition timing value according to the calculated advance/retardation correction coefficient and determining an output ignition timing value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for controlling ignition timing for all internal combustion engine to suppress engine knocking, comprising the steps of:
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a) detecting an engine revolution speed and n engine load; b) calculating a basic ignition timing value on the basis of the detected engine revolution speed and engine load; c) generating an ignition signal at a timing calculated in the step b) and igniting air fuel mixture supplied to the engine in response to the ignition signal d) generating a periodic pseudo random signal; e) superimposing the periodic pseudo random signal on the ignition signal; f) detecting engine knocking and outputting an engine knocking level signal which changes due to the superimposition of the periodic pseudo random signal; g) calculating a cross-correlation function of both the knocking level signal and pseudo random signal; h) determining whether the cross-correlation function coincides with a predetermined target value; i) calculating an advance/retardation correction coefficient of the ignition timing so that the cross-correlation function coincides with the predetermined target value; and j) correcting the basic ignition timing value according to the calculated advance/retardation correction coefficient and determining an output ignition timing value.
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Specification