Fuel injection detecting device
AssigneeDenso Corporation
InventorsMinoru Imai, Naoyuki Yamada
Life of this patent
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Abstract
A fuel injection detecting device computes an actual fuel-injection-end timing based on a rising waveform of the fuel pressure detected by a fuel sensor during a period in which the fuel pressure increases due to a fuel injection rate decrease. The rising waveform is modeled by a modeling formula. A reference pressure Ps(n) is substituted into the modeling formula, whereby a timing “te” is obtained as the fuel-injection-end timing.
Claims14
A fuel injection detecting device detecting a fuel injection condition, the fuel injection detecting device being applied to a fuel injection system in which a fuel injector injects a fuel accumulated in an accumulator and a multi-stage fuel injection is performed during one combustion cycle, the fuel injection detecting device comprising:
- a fuel pressure sensor provided in a fuel passage fluidly connecting the accumulator and a fuel injection port of the fuel injector, the fuel pressure sensor detecting a fuel pressure which varies due to a fuel injection from the fuel injection port;
- and
- a fuel-injection-end timing computing means for subtracting a fuel pressure waveform generated by former fuel injections until (n−1)-th (n≧2) fuel injection from the fuel pressure waveform detected by the fuel pressure sensor with respect to n-th (n≧2) fuel injection, and for computing an actual fuel-injection-end timing based on a rising waveform of the fuel pressure during a period in which the fuel pressure increases due to a fuel injection rate decrease;
- wherein:
- the fuel-injection-end timing computing means includes a modeling means for modeling the rising waveform by a mathematical formula, a reference pressure computing means for computing a reference pressure based on a fuel pressure right before a fuel pressure drop due to a fuel injection is generated, and the fuel-injection-end timing computing means computes the fuel-injection-end timing based on the mathematical formula modeled by the modeling means;
- the reference pressure computing means computes the reference pressure with respect to a first fuel injection, and
- the fuel-injection-end timing computing means subtracts a pressure drop amount depending a fuel injection amount of previous fuel injections from the reference pressure computed with respect to the first fuel injection, and defines the obtained pressure as a reference pressure for computing the fuel-injection-end timing of the second and successive fuel injection.
A fuel injection detecting device detecting a fuel injection condition, the fuel injection detecting device being applied to a fuel injection system in which a fuel injector injects a fuel accumulated in an accumulator and a multi-stage fuel injection is performed during one combustion cycle, the fuel injection detecting device comprising:
- a fuel pressure sensor provided in a fuel passage fluidly connecting the accumulator and a fuel injection port of the fuel injector, the fuel pressure sensor configured to detect a fuel pressure which varies due to a fuel injection from the fuel injection port;
- and
- a processing system, comprising a computer processor, the processing system being configured to:
- subject a fuel pressure waveform generated by former fuel injections until (n−1)-th (n≧2) fuel injection from the fuel pressure waveform detected by the fuel pressure sensor with respect to n-th (n≧2) fuel injection,
- compute an actual fuel-injection-end timing based on a rising waveform of the fuel pressure during a period in which the fuel pressure increases due to a fuel injection rate decrease,
- model the rising waveform by mathematical formula,
- compute a reference pressure based on a fuel pressure right before a fuel pressure drop due to a fuel injection is generated,
- compute the fuel-injection-end timing based on the mathematical formula,
- compute the reference pressure with respect to a first fuel injection,
- subtract a pressure drop amount depending a fuel injection amount of previous fuel injections from the reference pressure computed with respect to the first fuel injection, and
- define the obtained pressure as a reference pressure for computing the fuel-injection-end timing of the second and successive fuel injection.
The fuel injection detecting device according to 11,
- the processing system being configured to model the rising waveform by a straight line model and compute the fuel-injection-end timing based on the straight line model.
A method of detecting a fuel injection condition, the fuel injection detecting device being applied to a fuel injection system in which a fuel injector injects a fuel accumulated in an accumulator and a multi-stage fuel injection is performed during one combustion cycle, the method comprising:
- detecting, using a fuel pressure sensor provided in a fuel passage fluidly connecting the accumulator and a fuel injection port of the fuel injector, a fuel pressure which varies due to a fuel injection from the fuel injection port;
- subtracting a fuel pressure waveform generated by former fuel injections until (n−1)-th (n≧2) fuel injection form the fuel pressure waveform detected by the fuel pressure sensor with respect to n-th (n≧2) fuel injection;
- computing, using a processing system comprising a computer processor, an actual fuel-injection-end timing based on a rising waveform of the fuel pressure during a period in which the fuel pressure increases due to a fuel injection rate decrease;
- modeling the rising waveform by a mathematical formula;
- computing a reference pressure based on a fuel pressure right before a fuel pressure drop due to a fuel injection is generated;
- computing the fuel-injection-end timing based on the mathematical formula;
- computing the reference pressure with respect to a first fuel injection;
- subtracting a pressure drop amount depending a fuel injection amount of previous fuel injections from the reference pressure computed with respect to the first fuel injection;
- and
- defining the obtained pressure as a reference pressure for computing the fuel-injection-end timing of the second and successive fuel injection.
Dependencies are inferred from the claim text.