System for detecting an air filter condition, in particular for combustion engine

• US 10,126,203 B2
• Filed: 06/25/2015
• Issued: 11/13/2018
• Est. Priority Date: 06/27/2014
• Status: Active Grant

• Current Assignee: FPT Motorenforschung AG (Iveco Group NV)
• Original Assignee: FPT Motorenforschung AG (Iveco Group NV)
• Inventors: Eckhardt, Thomas
• Primary Examiner(s): Ward, Eric
• Assistant Examiner(s): Ashbahian, Eric
• Application Number:
  US14/749,946
• Publication Number:
  US 20160018288A1
• Time in Patent Office: 1,237 Days
• Field of Search: 95 19
• CPC Class Codes: B01D 46/0086 Filter condition indicators
• CPC Class Codes: B01D 46/446 by pressure measuring
• CPC Class Codes: F02M 35/024 using filters, e.g. moistened F02M35/026 takes precedence; cleaning of the filtering material F02M35/08
• CPC Class Codes: F02M 35/08 with means for removing dust, particles or liquids from cleaners; with means for indicating clogging; with by-pass means; Regeneration of cleaners
• CPC Class Codes: F02M 35/09 Clogging indicators ; Diagnosis or testing of air cleaners sensors therefore F02M35/10373
• CPC Class Codes: F02M 35/10373 Sensors for intake systems throttle position sensors F02D9/105
• CPC Class Codes: G01M 15/09 by monitoring pressure in fluid ducts, e.g. in lubrication or cooling parts

Abstract

Method for detecting an air filter condition, in particular for combustion engines, comprising the following steps: calculation of a linear regression over data-couples values, each comprising pressure drop value at the air filter and square of air flow value crossing the air filter, corresponding to said pressure drop value, in order to obtain an angular coefficient of the linear regression, comparison of the angular coefficient or of the function construed on the angular coefficient with at least one threshold in order to detect an operative condition of the air filter (FIG. 1).

Claims

1. Method for controlling a combustion engine on the basis of a detected air filter condition, comprising the following steps:

(ik) calculation of a linear regression over data-couples values, each comprising

pressure drop value (ia) at the air filter

square of air flow value (ib) crossing the air filter, corresponding to said pressure drop value,

in order to obtain an angular coefficient (k) of the linear regression,

(iki) comparison of said angular coefficient or of a function construed on said angular coefficient with at least one threshold ((ThL, Th1, ThU), (kMin, kMax), ({dot over (V)}_min², {dot over (V)}_max²)) in order to detect (ikii) an operative condition of the air filter, and

limiting speed of the engine when said angular coefficient (k) or said function construed on said angular coefficient exceeds a higher threshold (ThU) (k or f(k)>

ThU;

YES),

wherein said pressure drop value is acquired (v) by a differential pressure sensor or by subtracting

a first measured absolute pressure, measured by means of a first absolute pressure sensor arranged downstream of the air filter according to air flow direction, from

a second measured absolute pressure, measured by means of a second absolute pressure sensor arranged in the ambient.

2. Method according to claim 1, wherein, when (iki) said angular coefficient (k) or said function construed on said angular coefficient exceeds a higher threshold (ThU) (k or f(k)>

ThU;

YES), the air filter is acknowledged (ikii) as clogged.

3. Method according to claim 1, wherein, when (iki) said angular coefficient (k) or said function construed on said angular coefficient is lower than a lower threshold (ThL) (k or f(k)<

ThL;

YES), the air filter is acknowledged (ikii) as tampered or absent or the intake pipe is acknowledged as leaking.

4. Method according to claim 1, wherein (iki) said angular coefficient (k) or said function construed on said angular coefficient is compared with at least three thresholds ThL<

Th1<

ThU in order to detect one of the following at least four conditions;

First condition;

ThL<

k<

Th1;

filter is acknowledged as new and/or in good conditions;

Second condition;

Th1<

k<

ThU;

filter is acknowledged as dirty, but not yet dangerously clogged;

Third condition;

ThU<

k;

filter is acknowledged as dangerously clogged;

Fourth condition;

k<

ThL;

the angular coefficient k is acknowledged as too low even for a new filter, thus a severe dangerous condition is acknowledged;

no filter cartridge present,

wrong filter cartridge present,

intake leakage.

5. Method according to claim 4, comprising a step of detecting (ikiii) of a Fifth condition, when said angular coefficient (k) or a function construed on said angular coefficient suddenly passes from said Second or Third condition to the Fourth condition, indicating a tampering approach.

6. Method according to claim 5, further comprising limiting the speed of the engine when said Fourth or Fifth condition is detected.

7. Method according to claim 1, wherein, said function construed on said angular coefficient (k) is a theoretical maximal pressure drop (Δ

p_max) corresponding to a predefined theoretical maximal air flow value ({dot over (V)}_max).

8. Method according to claim 7, wherein said theoretical maximal pressure drop Δ

p_max is given by

Δ

p_max=k·

{dot over (V)}_max² 

 

Eq. 3

where {dot over (V)}_max coincides with said predefined theoretical maximal air flow value.

9. Method according to claim 1, wherein an applicable range [{dot over (V)}_min, {dot over (V)}_max] of air flows is subdivided (iii) into a predefined number of adjacent intervals (0-7), then, said data-couples values Δ

p, {dot over (V)}² are grouped (iv) on the basis of the respective interval belonging the air flow value {dot over (V)} and associated to the respective interval,

and wherein said angular coefficient k is calculated (ik) by means of the following formula

10. Method according to claim 9, further comprising a preliminary step (v) of acquisition of said data-couples Δ

p, {dot over (V)}² and a subsequent step of inhibition (vi) of said linear regression calculation, until at least a predefined number of intervals is associated with at least one data-couple.

11. Apparatus for controlling a combustion engine on the basis of a detected air filter condition, comprising

a differential pressure sensor or two or more absolute pressure sensors for acquiring (v) a pressure drop value at the air filter,

an air flow measuring device or electronic controller for acquiring (v) an air flow value crossing the air filter, corresponding to said pressure drop value

an ECU adapted to carry out steps including:

(ik) calculation of a linear regression over data-couples values, each comprising

pressure drop value (ia) at the air filter

square of air flow value (ib) crossing the air filter, corresponding to said pressure drop value,

in order to obtain an angular coefficient (k) of the linear regression,

(iki) comparison of said angular coefficient or of a function construed on said angular coefficient with at least one threshold ((ThL, Th1, ThU), (kMin, kMax), ({dot over (V)}_min², {dot over (V)}_max²)) in order to detect (ikii) an operative condition of the air filter, and

limiting speed of the engine when said angular coefficient (k) or said function construed on said angular coefficient exceeds a higher threshold (ThU) (k or f(k)>

ThU;

YES).

12. Combustion engine comprising an air filter and an apparatus for detecting its operative conditions according to claim 11.

13. Terrestrial vehicle comprising a combustion engine according to claim 12.

14. A non-transitory computer readable medium on which is recorded a program for controlling a combustion engine on the basis of a detected air filter condition, the program executable by a computer to perform steps comprising:

(ik) calculation of a linear regression over data-couples values, each comprising

pressure drop value (ia) at the air filter

square of air flow value (ib) crossing the air filter, corresponding to said pressure drop value,

in order to obtain an angular coefficient (k) of the linear regression,

(iki) comparison of said angular coefficient or of a function construed on said angular coefficient with at least one threshold ((ThL, Th1, ThU), (kMin, kMax), ({dot over (V)}_min², {dot over (V)}_max²)) in order to detect (ikii) an operative condition of the air filter, and

limiting speed of the engine when said angular coefficient (k) or said function construed on said angular coefficient exceeds a higher threshold (ThU) (k or f(k)>

ThU;

YES),

wherein said pressure drop value is acquired (v) by a differential pressure sensor or by subtracting

a first measured absolute pressure, measured by means of a first absolute pressure sensor arranged downstream of the air filter according to air flow direction, from

a second measured absolute pressure, measured by means of a second absolute pressure sensor arranged in the ambient.