Communications: electrical – Condition responsive indicating system – Specific condition
Reexamination Certificate
2000-06-15
2001-10-16
Lieu, Julie (Department: 2632)
Communications: electrical
Condition responsive indicating system
Specific condition
C340S644000, C340S635000, C324S523000
Reexamination Certificate
active
06304189
ABSTRACT:
BACKGROUND INFORMATION
The present invention concerns a method for detecting faulty switching operations of a first relay, whose switching element is connected in series with a load.
From German Patent No. 31 35 888, a method is described which functions to detect faulty switching operations of a relay whose switching element is connected in series with a load and which, in accordance with the switch position, interrupts or closes the connection to the load on the basis of switching commands. If a faulty switching operation is detected, either in the switching commands or in the relays, the driving load is supplied with potential such that it is prevented from starting up. The present detection of faults depends on the detection of given potentials and their quite complex evaluation.
SUMMARY OF THE INVENTION
In contrast, the method according to the present invention for detecting faulty switching operations of a first relay has the advantage of making available a simple and reliable solution, in which a relay test is carried out through a current measurement implemented in an electronic control unit. In an advantageous manner, all relays can therefore be triggered without one of the actuators, designated as load, having to be moved.
In the method according to the present invention, for this purpose, a current is measured that flows through a circuit containing the switching element, and a faulty functioning of the relay, in particular a sticking of the switching element, is detected if the current intensity does not correspond to the current intensity to be expected in accordance with the switch position selected.
According to a particularly effective refinement of the present invention, provision is made for at least one second relay, which, in a switch-over, can connect a first terminal of the circuit to at least two different potentials, and a second terminal of the circuit is connected to the first of the two potentials, and according to the present invention, a switching signal connecting the first terminal to the second potential is sent to the second relay and a switching signal to open is sent to the first relay, and a first fault signal characterizing a fault of the two relays is sent if a current flow is detected in the circuit.
In an advantageous embodiment of this refinement according to the present invention, provision is made that a switching signal for connecting the first terminal to the first potential is sent to the second relay, and a switching signal for closing is sent to the first relay, if no fault was detected in the preceding step, and that a fault signal characterizing a fault of the two relays is sent if a current flow is detected in the circuit.
In a further advantageous embodiment of the present invention, provision is made that a plurality of loads having assigned first relays are connected in parallel to the two terminals, and faults are detected in individual and/or a plurality of relays.
In a particularly advantageous and expedient refinement of the present invention, provision is made for a third relay, using which the second terminal can be connected to one of the two potentials. In accordance with an advantageous application of this refinement according to the present invention, by connecting the third relay, faulty functioning of the second relay is determined, and vice versa.
A further advantageous embodiment of the present invention is characterized by the use of a semiconductor switch in place of at least one of the relays.
REFERENCES:
patent: 5136280 (1992-08-01), Bjarne
patent: 5243291 (1993-09-01), Heihachiro
patent: 31 35 888 (1983-03-01), None
patent: 0 563 683 (1993-10-01), None
patent: 0 651 489 (1995-05-01), None
patent: 2 162 391 (1986-01-01), None
patent: 09 213471 (1997-08-01), None
Koch Stefan
Kremser Rolf
Soellner Michael
Kenyon & Kenyon
Lieu Julie
Robert & Bosch GmbH
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