US 2010/0250095 A1Published application

Fuel injection detecting device

AssigneeDenso Corporation

InventorsNaoyuki Yamada, Koji Ishizuka

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Abstract

A fuel injection detecting device computes a maximum-fuel-injection-rate-reach timing and a fuel-injection-rate-decrease-start timing based on a falling waveform of the fuel pressure and a rising waveform of the fuel pressure. The falling waveform represents 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 represents the fuel pressure detected by the fuel sensor during a period in which the fuel pressure decreases due to a fuel injection rate increase. The rising waveform and the falling waveform are respectively modeled by modeling function. In a case of small fuel injection quantity, an intersection timing at which lines expressed by the modeling functions intersect with each other is defined as the maximum-fuel-injection-rate-reach timing and the fuel-injection-rate-decrease-start timing.

Claims28

Dependent claims

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, 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 changing point computing means for computing a changing timing based on
a falling waveform of the fuel pressure during a period in which the fuel pressure decreases due to a fuel injection rate increase and
a rising waveform of the fuel pressure during a period in which the fuel pressure increases due to the fuel injection rate decrease, wherein
the changing timing is at least one of a fuel-injection-rate-decrease-start timing and a maximum-fuel-injection-rate-reach timing,
the fuel-injection-rate-decrease-start timing represents a timing at which the fuel injection rate starts to fall from a maximum fuel injection rate, and
the maximum-fuel-injection-rate-reach timing represents a timing at which the fuel injection rate becomes the maximum fuel injection rate.

5 more elements

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;
a falling-modeling means for modeling a falling waveform of the fuel pressure by a falling-modeling function during a period in which the fuel pressure decreases due to a fuel injection rate increase;
a rising-modeling means for modeling a rising waveform of the fuel pressure by a rising-modeling function during a period in which the fuel pressure increases due to a fuel injection rate decrease;
an intersection timing computing means for computing an intersection timing at which a first line expressed by the falling-modeling function and a second line expressed by the rising-modeling function intersect with each other,
an intersection pressure computing means for computing an intersection pressure at which a first line expressed by the falling-modeling function and a second line expressed by the rising-modeling function intersect with each other;
a reference pressure computing means for computing a reference pressure based on a fuel pressure right before the falling waveform is generated;
a determination means for determining whether a pressure difference between the reference pressure and the intersection pressure is smaller than or equal to a specified value;
and
a changing point computing means for computing
a maximum-fuel-injection-rate-reach timing at which an output of the falling-modeling function is the specified value and
a fuel-injection-rate-decrease-start timing at which an output of the rising-modeling function is the specified value in a case that the difference between the reference pressure and the intersection pressure is smaller than or equal to the specified value.

8 more elements

Dependencies are inferred from the claim text.