Method for computer-assisted determination of multiple rotational irregularities in internal combustion engine

Abstract

The invention relates to a method for computer-assisted and absolute determination of multiple rotational irregularities in an internal combustion engine. The method according to the invention comprises a number of combustion chambers having moving pistons which are mechanically interconnected via a crankshaft in order to set the crankshaft in rotation, by means of uneven running values (LURn-i, LURn) which are determined relatively for each combustion chamber, continuously and successively during operation of the internal combustion engine, in the logical sequence of the ignition of the combustion chambers, according to a predetermined calculation rule, from measurement variables of the combustion chamber being considered and measurement variables of the combustion chamber ignited immediately before. A particular uneven running value (LURn-i, LURn) represents a measurement of a rotational irregularity of the crankshaft resulting from the combustion chamber just ignited. The method according to the invention comprises, in a step a), determination (S1) of the uneven running value (LURn) of a currently ignited combustion chamber which, in the logical sequence of the ignition of the combustion chambers, is ignited immediately after a logically preceding combustion chamber, of which the uneven running value (LURn- i), ascertained for the preceding combustion chamber, has exceeded a predetermined threshold value (SW1) and indicates a fault in the preceding combustion chamber. In a step b), a compensating factor (f) is determined (S2), which represents the mutual influencing of the uneven running values (LURn-i, LURn) of the combustion chamber and the preceding combustion chamber. In a step c), a compensated uneven running value (cLURn) of the combustion chamber is determined (S3) from the uneven running value (LURn) of the combustion chamber and the compensating factor (f). Lastly, in a step d), the compensated uneven running value (cLURn) of the combustion chamber is compared (S4) with the predetermined threshold value (SW1) in order to determine whether or not the combustion chamber has a fault.

Description

technical field [0001] The invention relates to a method for the computer-aided determination of multiple rotational inhomogeneities of an internal combustion engine. An internal combustion engine comprises a plurality of combustion chambers with moving pistons which are mechanically interconnected by a crankshaft so as to set the crankshaft in rotation. The rotational inhomogeneity is determined with the aid of operating irregularity values ​​which are calculated continuously and successively in a logical sequence of combustion chamber firings for each combustion chamber during operation of the internal combustion engine according to a predetermined calculation. The rule is determined from the measured parameters of the combustion chamber being observed and the measured parameters of the combustion chamber just before firing, wherein the corresponding running irregularity value represents the contribution to the non-uniformity of crankshaft rotation due to the combustion cham...

AI Technical Summary

Problems solved by technology

However, multiple rotational inhomogeneities cannot be reliably detected due to the alternating influence of the running irregularity values

[0006] The problem that arises from this is that it is difficult to detect multiple rotational inhomogeneities, that is to say simultaneous faults in several cylinders, which lead to running irregularities determined with the aid of the sensor wheel, when the corresponding cylinders fire one after the other Generates a torque that deviates from the rated value

As a result, faults cannot be located without problems, or complex, sometimes also cost-intensive and repeated fault elimination tests are required

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