Method of monitoring an internal combustion engine ignition system by measuring spark duration or voltage and distinction between isolated errors and recurrent errors

A method of monitoring an ignition system of an internal combustion engine comprising the steps of:

• continually, contemporarily measuring engine operating parameters including engine speed and engine load, and deriving from combinations of said contemporarily measured parameters an indication of one condition of engine operation, within a range of several ranges of engine operation conditions;
• measuring, for a sequence of successive ignition sparks in at least one cylinder, the spark voltage, by sensing said spark voltage induced in a primary winding of an ignition coil;
• comparing, for an ignition spark of said sequence, spark duration represented by measured spark voltage with a previously stored limit value of spark duration thereby providing a designation of adequacy or deficiency, of the measured spark duration of said successive sparks in terms of spark voltage induced in said primary winding of said ignition coil;
• determining from at least one designation of deficiency among said designations of adequacy or deficiency whether a single malfunction recognition or a statistical recognition of malfunction from said sequence of ignition events is preferable, based on the condition of engine operation within the range;
• in the event of preference of a statistical recognition of malfunction, performing the following steps;
• in response to every ignition spark of said sequence for which a said deficiency is designated, incrementing a malfunction counter (FZ), by a predetermining first count value (B);
• in response to every ignition spark of said sequence for which no said deficiency is designated, decrementing said malfunction counter by a predetermined second count value, (A) said second count value being smaller than said first count value;
• and
• as soon as the count value of said malfunction counter exceeds a predetermined third count value which is at least twice as great as said first count value, producing at least a malfunction signal for the attention of a person using said internal combustion engine.

A method of monitoring an ignition system of an internal combustion engine comprising the steps of:

• continually, contemporarily measuring engine operating parameters including engine speed and engine load, and deriving from combination of said contemporarily measured parameters an indication of one condition of engine operation of several engine conditions within a plurality of operating condition ranges, wherein said ranges have limit values of said parameters;
• measuring, for a sequence of successive ignition sparks, in at least one cylinder the spark voltage, by sensing said spark voltage induced in a primary winding of an ignition coil, said limit values being in terms of spark voltage induced in said primary winding of said ignition coil;
• comparing, for an ignition spark of said sequence, the measured spark voltage with a previously stored limit value of spark voltage and in each case providing a designation of adequacy or deficiency;
• determining from at least one designation of deficiency among said designations of adequacy or deficiency whether a single malfunction recognition or a statistical recognition of malfunction from said sequence of ignition sparks is preferable, based on the condition of engine operation within one of said ranges;
• in the event of preference of a statistical recognition of malfunction, performing the following steps:
• in response to every ignition spark of said sequence for which a said deficiency is designated, incrementing a malfunction counter (FZ), by a predetermining first count value (B);
• in response to every ignition spark of said sequence for which no said deficiency is designated, decrementing said malfunction counter by a predetermined second count value (A), said second count value being smaller than said first count value;
• and
• as soon as the count value of said malfunction counter exceeds a predetermined third count value which is at least twice as great as said first count value, producing at least a malfunction signal for the attention of a person using said internal combustion engine.