| 摘要 |
1. A process for measuring the ageing of an internal combustion engine and for regulating operation thereof characterized in that it involves the following steps comprising : a) using a device for angular detection of the position of the crankshaft using a target (1) provided with teeth which are regularly spaced except in respect of interruptions (3) for absolute detection, said teeth passing in front of a sensor (2) associated with a pulse shaping means (4), which means may be the same as that used for the electronic ignition of the engine, b) determining on the target (1) angular windows (F) which are equal in number to the number of explosions per revolution, of which the sum of the angular values over a revolution represents 180 degrees and whose beginning is displaced by about 8 degrees et 10 degrees in the retard direction relative to the corresponding top dead centre point, c) calculating from a clock frequency by digital processing the periods (TF) for which said varrious windows pass and producing the sum thereof of over a revolution, and then calculating a first value which is the absolute value of the difference between said sum for a revolution and that of the previous revolution, d) calculating the time of the period of rotation over a revolution (TP) and calculating a second value as the absolute value of the difference between the periods of rotation of two successive revolutions, e) calculating a third value as the absolute value of the difference between double the first value calculated in c) and the second value calculated in d), f) calculating an instantaneous instability criterion (C) as the absolute value of the difference between the third value calculated in e) and a correction term (K) which is a function of the level of precision of the measurements and which is of the order of 7 microseconds for a clock frequency of 1 MHz, g) diving the term obtained in f) by the cube of the period of rotation (TP) which was previously determined, h) calculating a relative criterion (Cn) as the relationship between the number of times over n revolutions in which the preceding instantaneous criterion (C) has exceeded an experimetally determined threshold (S), and said number n of revolutions, and finally i) determining the minimum and maximum tolerances a and b respectively for the relative criterion (Cn), diagnosing a state of ageing of the engine by determining the amount by which the criterion (Cn) deviated from said tolerances and acting on at least one of the operating parameters of the engine in the required direction to maintain said relative criterion (Cn) within the tolerances (a, b).
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