Fuel composition estimation and control of fuel injection
First Claim
1. A method for estimating a composition of a fuel within an engine, comprising performing the following steps under ambient conditions:
- (a′
) determining an ambient temperature of the fuel;
(a) monitoring a fuel pressure inside a fuel rail of the engine over a period of time;
(b) calculating at least one frequency component of the change in fuel pressure;
(c) calculating a speed of sound transmission c on the basis of the at least one frequency component; and
(d) estimating the composition of the fuel on the basis of the calculated speed of sound transmission at said ambient temperaturewherein the fuel comprises a biodiesel.
3 Assignments
0 Petitions
Accused Products
Abstract
A method for estimating the composition of a fuel within an engine, comprises performing the following steps under ambient conditions: (a′) determining the ambient temperature of the fuel; (a) monitoring the fuel pressure inside a fuel rail of the engine over a period of time; (b) calculating at least one frequency component of the change in fuel pressure; (c) calculating the speed of sound transmission c on the basis of the at least one frequency component; and (d) estimating the composition of the fuel on the basis of the calculated speed of sound transmission at said ambient temperature. Suitably, the speed of sound transmission in the fuel is calculated using the equation: c=fλ, where the wavelength λ of the standing wave with frequency f is 2L, where L is the length of the fuel rail. Also described are methods for estimating the temperature of the fuel at a non-ambient temperature, and determining a fuels physical properties. Methods for controlling a fuel injection system in an engine according to the determined physical properties of the fuel and the resultant fuel injection system are also described.
35 Citations
20 Claims
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1. A method for estimating a composition of a fuel within an engine, comprising performing the following steps under ambient conditions:
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(a′
) determining an ambient temperature of the fuel;(a) monitoring a fuel pressure inside a fuel rail of the engine over a period of time; (b) calculating at least one frequency component of the change in fuel pressure; (c) calculating a speed of sound transmission c on the basis of the at least one frequency component; and (d) estimating the composition of the fuel on the basis of the calculated speed of sound transmission at said ambient temperature wherein the fuel comprises a biodiesel. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A method for estimating a composition of a fuel within an engine, comprising performing the following steps under ambient conditions:
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(a′
) determining an ambient temperature of the fuel;(a) monitoring a fuel pressure inside a fuel rail of the engine over a period of time; (b) calculating at least one frequency component of the change in fuel pressure; (c) calculating a speed of sound transmission c on the basis of the at least one frequency component; and (d) estimating the composition of the fuel on the basis of the calculated speed of sound transmission at said ambient temperature.
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17. A fuel injection control system for an engine having one or more engine cylinders, comprising:
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means for estimating a composition of the fuel within an engine at ambient conditions; means for estimating at least one physical property of the fuel under the ambient conditions on the basis of the estimated fuel composition; means for estimating mass-flow rate of the fuel under the ambient conditions; and means for adjusting the start and end points of a fuel injection event controlled by the fuel injection system on the basis of the mass-flow rate of the fuel, such that a predetermined mass of fuel is injected into the one or more engine cylinders in said fuel injection event at start-up; and optionally which further comprises; means for estimating a temperature of the fuel within an engine under non-ambient conditions; means for estimating at least one physical property of the fuel under the non-ambient conditions on the basis of the non-ambient temperature; means for estimating mass-flow rate of the fuel under the non-ambient conditions; and means for adjusting the start and end points of a fuel injection event controlled by the fuel injection system on the basis of the mass-flow rate, such that a predetermined mass of fuel is injected into the one or more engine cylinders in said fuel injection event under non-ambient conditions. - View Dependent Claims (18, 19, 20)
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Specification