Fuel-injection condition detector
AssigneeDenso Corporation
InventorYoshimitsu TAKASHIMA
Life of this patent
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Abstract
A fuel-injection condition detector includes a first approximate portion which approximates a plurality of fuel pressure values representing the descent pressure waveform or the ascent pressure waveform into a least-squares approximate line by least-squares method; and a weighting portion which applies a weight to the fuel pressure value. The weight is set greater as a difference between the fuel pressure and the least-squares approximate line is larger. Then, the weighted values are approximated into a weighted approximate line by the least-squares method.
Claims2
A fuel-injection condition detector applied to a fuel injection system in which a fuel injector injects a fuel accumulated in an accumulator, the fuel-injection condition detector comprising:
- a fuel pressure sensor detecting a fuel pressure in a fuel supply passage from the accumulator to an injection port of the fuel injector;
- an approximate means for approximating a descent pressure waveform or an ascent pressure waveform to a straight line, the descent pressure waveform and the ascent pressure waveform being a part of a pressure waveform detected by the fuel pressure sensor, the descent pressure waveform representing a decreasing fuel pressure due to an opening of the injection port, the ascent pressure waveform representing an increasing fuel pressure due to a closing of the injection port;
- and
- an injection condition estimating means for estimating a fuel-injection condition based on the straight line approximated by the approximate means, wherein
- the approximate means includes:
- a first approximate means for approximating a plurality of fuel pressure values representing the descent pressure waveform or the ascent pressure waveform into a least-squares approximate line by least-squares method;
- a weighting means for applying a weight to the fuel pressure value, the weight being set greater as a difference between the fuel pressure and the least-squares approximate line is larger;
- and
- a second approximate means for approximating the fuel pressure value having the weight into a weighted approximate line by the least-squares method.
A fuel-injection condition detector applied to a fuel injection system in which a fuel injector injects a fuel accumulated in an accumulator, the fuel-injection condition detector comprising:
- a fuel pressure sensor detecting a fuel pressure in a fuel supply passage from the accumulator to an injection port of the fuel injector;
- an approximate means for approximating a descent pressure waveform or an ascent pressure waveform to a straight line, the descent pressure waveform and the ascent pressure waveform being a part of a pressure waveform detected by the fuel pressure sensor, the descent pressure waveform representing a decreasing fuel pressure due to an opening of the injection port, the ascent pressure waveform representing an increasing fuel pressure due to a closing of the injection port;
- and
- an injection condition estimating means for estimating a fuel-injection condition based on the straight line approximated by the approximating means;
- wherein
- the approximate means includes:
- a computing means for computing a minimum differentiation value point at which a slope of the descent pressure waveform is minimum, or for computing a maximum differentiation value point at which a slope of the ascent pressure waveform is maximum,
- a weighting means for applying a weight to the fuel pressure value, the weight being set greater as the fuel pressure is more close to the minimum differentiation value point or the maximum differentiation value point;
- and
- a weighted approximate means for approximating the fuel pressure value having the weight into a weighted approximate line by the least-squares method.
Dependencies are inferred from the claim text.