Method and device for evaluating ionic current signals for assessing combustion processes
First Claim
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1. A method for detecting combustion misfires in an internal combustion engine, the method comprising the steps of:
- subjecting a measured ionic current signal to a floating short-time integration using a floating short-time integrator;
forming a feature which corresponds to the maximum value of the floating short-time integrator within the entire measuring window with said short-time integrator having a window length shorter than said entire measuring window; and
, floatingly displacing said window length over said measuring window.
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Abstract
A method and an arrangement for detecting combustion misfires in internal combustion engines are presented where a measured ionic current signal is subjected to a floating short-time integration and a feature is formed which corresponds to the maximum value of the floating short-time integrator within the entire measuring window. The window length of the short-time integrator is shorter than the total measuring window and is floatingly displaced over the measuring window.
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Citations
8 Claims
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1. A method for detecting combustion misfires in an internal combustion engine, the method comprising the steps of:
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subjecting a measured ionic current signal to a floating short-time integration using a floating short-time integrator;
forming a feature which corresponds to the maximum value of the floating short-time integrator within the entire measuring window with said short-time integrator having a window length shorter than said entire measuring window; and
,floatingly displacing said window length over said measuring window. - View Dependent Claims (2, 3, 4)
after subjecting the measured ionic current signal to a floating short-time integration, supplying the output value of said short-time integrator to a maximum value former as soon as an enabling condition is satisfied;
recognizing said enabling condition as being satisfied when said ionic current signal has continuously exceeded an adjustable threshold value for an adjustable time duration; and
,immediately withdrawing said enabling condition when there is a drop below said threshold value.
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4. The method of claim 1, wherein said threshold value and said time duration are dependent upon engine and physical peripheral conditions including engine speed, load and ionic current amplitude.
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5. An arrangement for detecting combustion misfires in an internal combustion engine, the arrangement comprising:
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means for subjecting a measured ionic current signal to a floating short-time integration using a floating short-time integrator;
means for forming a feature which corresponds to the maximum value of the floating short-time integrator within the entire measuring window with said short-time integrator having a window length shorter than said entire measuring window; and
,means for floatingly displacing said window length over said measuring window. - View Dependent Claims (6, 7, 8)
means for supplying the output value of said short-time integrator to a maximum value former as soon as an enabling condition is satisfied after having subjected said measured ionic current signal to a floating short-time integration;
means for recognizing said enabling condition as being satisfied when said ionic current signal has continuously exceeded an adjustable threshold value for an adjustable time duration; and
,means for immediately withdrawing said enabling condition when there is a drop below said threshold value.
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8. The arrangement of claim 5, wherein said threshold value and said time duration are dependent upon engine and physical peripheral conditions including engine speed, load and ionic current amplitude.
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