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AssigneeMagnetic Marelli S.p.A.
InventorsMarco Berti, Piero Carbonaro, Daniele Ceccarini, Luca Poggio
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A circuit for monitoring and diagnosing an oxygen probe provided with a sensitive cell connected between a first and a second signal terminal, and a heating member connected between a battery and a heating terminal; the circuit includes an interface stage and a control unit. The interface stage includes a first resistor connected between a switch which is normally open and a supply line at a known potential and the first signal terminal, a second resistor connected between the first signal terminal and a second signal terminal and a third resistor connected between the second signal terminal and reference potential line. The control unit further includes a first analog-digital converter connected to the first signal terminal and a second analog-digital converter connected to the second signal terminal.
A circuit for monitoring and diagnosing an oxygen probe (2) provided with a sensitive cell (3) connected between a first and a second signal terminal (6, 7) and a heating member (10) connected between a battery (11) and a heating terminal (12), the circuit comprising an interface stage (15) and a control unit (16), the interface stage (15) comprising a first resistor (20) connected between a supply line (22) and the first signal terminal (6) of the oxygen probe (2), and a second resistor (23) connected between the first signal terminal (6) and the second signal terminal (7) of the oxygen probe (2), the circuit being characterized in that the control unit (16) comprises first analog-digital converter means (26) connected to the first signal terminal (6), and the second analog-digital converter means (27) connected to the second signal terminal (7) and in that the interface stage (15) comprises a third resistor (24) connected between the second signal terminal (7) and a reference potential line.
A method for monitoring and diagnosing an oxygen probe (2), provided with a sensitive cell (3) connected between a first and a second signal terminal (6, 7) and supplying an output voltage (Vλ), and a heating member (10) connected between a battery (11) and a heating terminal (12), the oxygen probe being connected to a monitoring and diagnosis circuit (1) having an interface stage (15) and a control unit (16) comprising first and second analog-digital converter means (26, 27) connected respectively to the first and the second signal terminals (6, 7), this interface stage (15) comprising a first resistor (20) connected between a supply line (22) and the first signal terminal (6) and having a first resistance value (R1), a second resistor (23) connected between the first and second signal terminals (6, 7) and having a second resistance value (R2), a third resistor (24) connected between the second signal terminal (7) and a reference potential line and having a third resistance value (R3), and interface switch means (21) disposed between the supply line (22) and the first resistor (20), the method comprising the stages of:
Dependencies are inferred from the claim text.