Claims
- 1. An apparatus for driving a fuel injection valve, comprising:
- a piezoelectric actuator having an opening time;
- a charging device for charging said piezoelectric actuator;
- a discharging device for discharging said piezoelectric actuator;
- a monitoring device connected in parallel with said piezoelectric actuator;
- a discharging switch connected in parallel with said piezoelectric actuator and actuated by said monitoring device in the event of a fault; and
- said monitoring device having a timer turning on said discharging switch if the opening time of said piezoelectric actuator exceeds a predetermined monitoring time.
- 2. The apparatus according to claim 1, wherein said monitoring device is supplied with voltage while said piezoelectric actuator is being charged.
- 3. The apparatus according to claim 1, including a Zener diode connected in parallel with said piezoelectric actuator, said monitoring apparatus, said discharging switch and said Zener diode constructed as an integrated circuit.
- 4. The apparatus according to claim 3, wherein said integrated circuit is disposed inside a housing of a fuel injection valve.
- 5. A method for operating the apparatus according to claim 1, which comprises dimensioning the monitoring time of said monitoring device to be slightly longer than a maximum opening time of a fuel injection valve required to inject a maximum quantity of fuel at a maximum fuel pressure.
- 6. The method according to claim 5, which comprises carrying out at least two injection operations with opening times not exceeding the maximum opening time for each cylinder filling operation, in a starting phase of an internal combustion engine.
- 7. A method for operating the apparatus according to claim 1, which comprises turning off said monitoring device in a starting phase of an internal combustion engine.
- 8. The method according to claim 7, which comprises carrying out the step of turning off said monitoring device with a frequency-modulated signal output by a control circuit.
Priority Claims (1)
Number |
Date |
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197 11 903 |
Mar 1997 |
DEX |
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CROSS-REFERENCE TO RELATED APPLICATION
This application is a continuation of copending International Application No. PCT/DE98/00837, filed Mar. 20, 1998, which designated the United States.
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Continuations (1)
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Number |
Date |
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Parent |
PCTDE9800837 |
Mar 1998 |
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