Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Vehicle diagnosis or maintenance indication
Reexamination Certificate
1999-10-12
2001-05-01
Dombroske, George (Department: 2855)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Vehicle diagnosis or maintenance indication
C073S116070, C073S117020, C073S118040, C701S031000
Reexamination Certificate
active
06226576
ABSTRACT:
The invention relates to a process for monitoring and error detection, particularly in a device for head detection of an internal combustion engine, according to the preamble to the main claim.
1. Prior Art
It is known that in internal combustion engines with knock control, the knock sensor and the associated signal processing circuit have to be monitored with regard to their functional performance. Otherwise, there is the danger that in the event of a failure of the knock sensor or a defect in the associated evaluation circuit, knocking will not be detected and the operating point of the engine will be undesirably shifted into the knocking region, which can lead to the engine being endangered. In connection with devices for knock detection, methods for error detection are therefore proposed, which permit a reliable malfunction of the knock sensor or the evaluation circuit to be detected.
The International Patent Application PCT/DE 94/01041 has disclosed a method for error detection in a device for knock detection in an internal combustion engine, in which the output signals of the knock sensor are compared to a variable reference level, which is produced as a function of preceding output signals of the knock sensor. If the knock signals exceed a level that corresponds to the reference level multiplied by a cylinder-selective knock detection factor, knocking is detected. If the reference level, which is normalized so that it increases with the increasing noise of the engine, exceeds a permitted reference level band, then an error is detected. In order to increase the reliability of the error detection, an error indicator is only triggered when the reference level lies outside the reference level band for a period of time that can be predetermined.
2. Advantages of the Invention
The method for monitoring and error detection according to the invention, particularly in a device for knock detection in an internal combustion engine, has the advantage that an additional increase in the reliability of the error detection is achieved in comparison to embodiments that are known from the prior art. This advantage is attained by virtue of the fact that in a method for error detection with the features of claim
1
, two different diagnosis functions are used and the two diagnosis functions are carried out in alternating fashion at fixed intervals. If one of the two diagnosis functions gives rise to the suspicion of an error, this diagnosis function is carried out an additional time or more often in order to verify the error message before the change-over to the other diagnosis function. If the error is confirmed, then an error is detected; if the error is not confirmed, then the process continues with the alternatingly executed diagnosis. The method is advantageously used analogously also when an error is cleared up. If an error that has been confirmed by a diagnosis is no longer occurring, this diagnosis is repeated at least once for confirmation before the error correction is acknowledged.
Other advantages of the invention are attained with the aid of the measures disclosed in the dependent claims. It is advantageous in this connection that the interval between the execution of the diagnosis functions can be determined as a time interval or, with the use in the control unit of an internal combustion engine, can also be determined as a number of combustions or work cycles. This permits an advantageous adaptation to various evaluation processes to be carried out. The two diagnosis functions contain separate debouncing counters for the sake of reliable error detection, with which the duration of the malfunction can also be taken into account in the error detection. If a diagnosis function has given rise to the suspicion of an error, the diagnoses are no longer carried out in alternating fashion, but rather the function that has produced the suspicion of an error is restarted and executed, wherein the interval, i.e. the time interval, the number of combustions, or the number of work cycles between two diagnoses can be reduced in comparison to the normal value. Therefore a rapid confirmation of the error suspicion or an elimination of the error suspicion can be produced in a particularly advantageous manner; this is particularly true when the interval becomes smaller. As soon as the error has been detected with certainty, or as soon as the error suspicion no longer exists, the normal state is re-activated and both diagnosis functions are executed in alternating fashion. This advantageously also applies for an error that has been detected but has been cleared up. A zero test and a test pulse are generated in a particularly advantageous manner as diagnosis functions, which in the normal state, are both alternatingly switched to the evaluation circuit.
The method for monitoring and error detection according to the invention can be used in a particularly advantageous manner in a device for knock detection in an internal combustion engine.
REFERENCES:
patent: 4418567 (1983-12-01), Boening et al.
patent: 4462362 (1984-07-01), Bonitz et al.
patent: 4521769 (1985-06-01), Dudeck et al.
patent: 4593553 (1986-06-01), Bonitz et al.
patent: 4821194 (1989-04-01), Kawamura
patent: 4981124 (1991-01-01), Sellner et al.
patent: 5088044 (1992-02-01), Matsuura
patent: 5414645 (1995-05-01), Hirano
patent: 5517969 (1996-05-01), Unland et al.
patent: 5522254 (1996-06-01), Kamabora et al.
patent: 5964811 (1999-10-01), Ishii et al.
patent: 720007 A1 (1996-07-01), None
patent: PCT/DE94/01041 (1994-09-01), None
Baeuerle Michael
Franke Steffen
Haeming Werner
Kluth Carsten
Surjadi Iwan
Dombroske George
Robert & Bosch GmbH
Striker Michael J.
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