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Method for detecting clogging in a fuel filter in an internal combustion engine supply circuit

Imported: 24 Feb '17 | Published: 06 Jan '04

Henri Mazet

USPTO - Utility Patents

Abstract

The invention concerns a method for detecting clogging in a fuel filter, between a fuel pressure regulator imposing a pressure towards the internal combustion engine downstream of the filter and an electric motor pump compressing fuel coming from the tank towards the regulator through the filter which consists in: determining the fuel pressure at the pump output and by considering it as the fuel pressure at the filter intake; determining the fuel pressure at the filter outlet as being the pressure imposed by the regulator; determining the pressure drop of the filter from the difference between the filter input and output pressure levels, and by comparing at least a value based on the pressure drop with at least a reference value to deduce therefrom information concerning the clogging condition of the filter. The invention is applicable to preventive or predictive maintenance of fuel supply circuits in internal combustion engines.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Other advantages and features of the invention will become clear from the example of an embodiment given below, which is not restrictive in any respect, described with reference to the appended drawings, of which:

FIG. 1 is a schematic view of the fuel supply circuit of an injection engine and

FIG. 2 is a block diagram showing a part of the electronic control unit of the circuit illustrated in FIG. 1, used to compute the pressure drop in the filter of this circuit.

Claims

1. A method of detecting clogging in a fuel filter having a filter intake and a filter outlet and provided in a fuel supply circuit of an internal combustion engine, and disposed between a fuel pressure regulator downstream of said filter and operating on a bypass system delivering fuel at an imposed pressure upstream and towards said internal combustion engine and a pump for delivering fuel from a tank, said pump being disposed upstream of said filter and supplying said regulator via said filter of which said filter intake is connected to a pump output and said filter outlet is connected to a regulator inlet, wherein said method comprises at least the following steps,

2. Method as claimed in claim 1, consisting of determining said first fuel pressure at said pump output by measuring said first fuel pressure by means of at least one pressure sensor between said pump output and said filter intake.

3. A method as claimed in claim 1, consisting of determining said first fuel pressure at said pump output on the basis of at least one relationship between said first fuel pressure and at least one of operating parameters of said pump, which are the instantaneous rotation speed of said pump, the mean supply current of an electric motor driving said pump and the thermal state of said pump.

4. A method as claimed in claim 3, consisting of driving said pump by use of an electric motor with a commutating collector and determining said pump instantaneous rotation speed on the basis of at least the instantaneous rotation speed of said electric motor, which is determined by analysing the instantaneous current in said electric motor and detecting commutations of said motor collector.

5. A method as claimed in claim 3, consisting of determining said mean supply current of said electric motor by measuring a drop in voltage at terminals of a shunt in an electric supply circuit of said motor.

6. A method as claimed in claim 3, consisting of determining said pump thermal state by measuring or estimating the temperature of said pump on the basis of at least one relationship between said pump temperature and at least one operating parameter of said pump.

7. A method as claimed in claim 1, wherein the step of comparing at least one value based on said pressure drop with at least one reference value incorporates at least one comparison of at least one absolute value of said filter pressure drop for at least one work rate or at least a given work rate range of said circuit with at least one threshold value for at least said rate or at least said range of fuel rate.

8. A method as claimed in claim 1, wherein the step of comparing at least one value based on said pressure drop with at least one reference value incorporates at least a comparison of at least one slope value for a pressure drop variation in said filter over time with at least a slope threshold for at least one work rate or at least a given work rate range of said circuit.

9. A method as claimed in claim 1, wherein the step of comparing at least one value based on said filter pressure drop with at least one reference value incorporates at least one comparison of at least one absolute value or slope value of a pressure drop variation in said filter at a given instant with at least a similar value at least a previous instant for at least one work rate or at least a given work rate range of said circuit.

10. A device for detecting clogging in a fuel filter of a fuel supply circuit of an internal combustion engine, said filter being disposed between an output of a pump driven by an electric motor and delivering fuel from a tank, and an inlet of a fuel pressure regulator supplied by said pump via said filter and imposing a fuel pressure towards said engine and towards said filter, said device comprising at least one electronic control unit, controlling operation of said pump and said electric drive motor, and which, on the one hand, knows said fuel pressure imposed by said regulator depending on fuel requirements of said engine, and, on the other hand, determines a fuel pressure at said pump output on the basis of at least one of operating parameters of said pump including the instantaneous rotation speed of said pump, the mean supply current of said electric drive motor and the thermal state of said pump, said electronic control unit computing a pressure drop in said filter as being the difference between a fuel pressure at said pump output and said imposed fuel pressure as imposed by said regulator, and comparing at least one value based on said pressure drop or at least one variation in said pressure drop with at least one reference value in order to deduce information therefrom about the state of clogging in said filter.