Bistable solenoid valve device, and method for monitoring it

A bistable solenoid valve device for a fluid system, wherein the bistable solenoid valve device comprises a bistable solenoid valve, the bistable solenoid valve comprising:

• a permanent magnet;
• an armature displaceable between a first armature position and a second armature position;
• a first switching coil for energization for a displacement of the armature into the first armature position;
• a second switching coil for energization for a displacement of the armature into the second armature position;
• and
• an evaluation device adapted to measure an induced coil voltage, an induced coil current, or both the induced coil voltage and the induced coil current, at one or more of the non-energized switching coils, and assess a switching behavior of the armature;
• wherein, when an ignition is switched on, a positive bias voltage is superposed on a negative induced coil voltage in order to generate a positive output signal.

A bistable solenoid valve device for a fluid system, wherein the bistable solenoid valve device comprises a bistable solenoid valve, the bistable solenoid valve comprising:

• a permanent magnet;
• an armature displaceable between a first armature position and a second armature position;
• a first switching coil for energization for a displacement of the armature into the first armature position;
• a second switching coil for energization for a displacement of the armature into the second armature position;
• and
• an evaluation device adapted to measure an induced coil voltage, an induced coil current, or both the induced coil voltage and the induced coil current, at one or more of the non-energized switching coils, and assess a switching behavior of the armature, wherein:
• in a switched-off state of the control device or when the ignition is switched off, the switching coils, the induced coil voltage, or both the switching coils and the induced coil voltage, are monitored for a positive voltage pulse;
• and
• in a switched-on state of the control device or when the ignition is switched on, a positive bias voltage is superposed onto the induced coil voltage by a functional device.

A method for monitoring a bistable solenoid valve device, the bistable solenoid valve device comprising an armature, and a first switching coil and a second switching coil for switching the armature into a first armature position or second armature position, the method comprising:

• actuating a control device for a first switching process into the first armature position, to output a first switching signal wherein the second switching coil has zero current;
• actuating the control device for a second switching process into the second armature position, to output a second switching signal for energizing a second switching coil wherein the first switching coil has zero current;
• wherein, in a quiescent mode, the two switching coils are not energized;
• monitoring, in each case, in a switching process, in the quiescent mode, or both the switching process and the quiescent mode, at least one non-energized switching coil for an induced coil current or induced coil voltage;
• and
• determining from the monitoring step whether there is a switching process present.