Process and system for detecting misfiring in internal combustion engines
First Claim
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1. A process for detecting misfires in an internal combustion engine comprising the steps of:
- detecting an indicated torque value for each expected combustion of the engine, and generating a sequence of said indicated torque values corresponding to said expected combustions,generating a cycle signal by combining at least two successive values of said sequence of indicated torque values,determining a peak value of said cycle signal,determining a threshold value corresponding to an expected torque of the engine in the presence of effective combustion, andcomparing said peak value with said threshold value and evaluating whether said peak value differs from said threshold value so as to identify a misfire of said engine.
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Abstract
Starting from a sequence of values of indicated torque detected for each expected combustion in the engine a cycle signal is generated as a combination of at least two successive values of the said sequence. The peak value of the said cycle signal is then compared with a comparison threshold chosen preferably in proportion of the fuel injection duration into the cylinders. Misfires are identified preferably from the result of a comparison between the said peak value and the said comparison threshold which differs from the result of comparison in the presence of regular operation of the engine.
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Citations
18 Claims
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1. A process for detecting misfires in an internal combustion engine comprising the steps of:
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detecting an indicated torque value for each expected combustion of the engine, and generating a sequence of said indicated torque values corresponding to said expected combustions, generating a cycle signal by combining at least two successive values of said sequence of indicated torque values, determining a peak value of said cycle signal, determining a threshold value corresponding to an expected torque of the engine in the presence of effective combustion, and comparing said peak value with said threshold value and evaluating whether said peak value differs from said threshold value so as to identify a misfire of said engine. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A system for detecting misfires in an internal combustion engine, said system including:
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first sensor means for detecting an instantaneous speed and phase of rotation of said engine, passage of engine cylinders through a top dead center position and a duration of fuel injection into the cylinders of the engine, processor means for determining from the engine speed signal, for each expected combustion a value of an indicated torque of the engine, thus generating a corresponding sequence of values;
wherein said processor means generates as a combination of at least two successive values of said sequence, a cycle signal, determines a peak value of said cycle signal, and determines a threshold value corresponding to the expected torque of the engine in the presence of effective combustion; and
compares said peak value with said threshold value and determines whether said peak value differs from said threshold value so as to indicate a misfire of the engine, anddisplay means controlled by said processor means to present the result of said comparisons and determining whether said peak value differs from said threshold value so as to identify a misfire of said engine. - View Dependent Claims (18)
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Specification