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US 8,474,309 B2Granted
Noise existence diagnosis device for fuel injection system
AssigneeDenso Corporation
InventorKou Komatsu
Life of this patent
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Abstract
A waveform detector detects a variation in fuel pressure generated by an injection based on a detection value of a fuel pressure sensor as a fuel pressure waveform. A differential calculator calculates a differential waveform representing a variation in differential value of the fuel pressure waveform. A noise determiner determines that noise overlaps with the fuel pressure waveform when the differential waveform has a value higher than a predetermined upper threshold or when the differential waveform has a value lower than a predetermined lower threshold.
Claims6
A noise existence diagnosis device for a fuel injection system comprising:
- a fuel injection valve that injects fuel accumulated in an accumulator;
- a fuel pressure sensor that detects a fuel pressure in a fuel supply passage from the accumulator to an injection port of the fuel injection valve;
- a waveform detector that detects a variation in the fuel pressure based on a detection value of the fuel pressure sensor as a fuel pressure waveform when the variation is generated by a fuel injection;
- a differential calculator that calculates a differential waveform representing a variation in differential value of the fuel pressure waveform;
- and
- a noise determiner that determines that noise overlaps with the fuel pressure waveform when the differential waveform has a value higher than a predetermined upper threshold or when the differential waveform has a value lower than a predetermined lower threshold.
3 more elements
Dependencies are inferred from the claim text.