FUEL VOLATILITY RECOGNITION METHOD DURING THE POST-CRANKING STEP OF AN INTERNAL COMBUSTION ENGINE

• US 20090107226A1
• Filed: 09/15/2008
• Published: 04/30/2009
• Est. Priority Date: 09/13/2007
• Status: Abandoned Application

• Current Assignee: Magneti Marelli Powertrain S.p.A. (Magneti Marelli S.p.A.)
• Original Assignee: Magneti Marelli Powertrain S.p.A. (Magneti Marelli S.p.A.)
• Inventors: CATERINI, Canio Rocco, Zecca, Luca, Sala De Llobet, Carlo Enrico, Zanotti, Massimo, Lambertini, Loris
• Application Number:
  US12/210,257
• Publication Number:
  US 20090107226A1
• Time in Patent Office: Days
• US Class Current: 73/114.380
• CPC Class Codes: B60K 2006/4808 Electric machine connected or connectable to gearbox output shaft
• CPC Class Codes: B60K 2006/4825 Electric machine connected or connectable to gearbox input shaft
• CPC Class Codes: B60K 6/48 Parallel type
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 20/00 Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: B60W 20/19 for achieving enhanced acceleration
• CPC Class Codes: B60W 2510/244 Charge state
• CPC Class Codes: B60W 2540/10 Accelerator pedal position
• CPC Class Codes: B60W 2710/0666 Engine torque
• CPC Class Codes: B60W 2710/083 Torque
• CPC Class Codes: B60W 2710/105 Output torque
• CPC Class Codes: B60W 50/06 Improving the dynamic response of the control system, e.g. improving the speed of regulation or avoiding hunting or overshoot
• CPC Class Codes: F02D 19/061 by controlling fuel injectors
• CPC Class Codes: F02D 19/0636 by estimation, i.e. without using direct measurements of a corresponding sensor
• CPC Class Codes: F02D 19/0649 Liquid fuels having different boiling temperatures, volatilities, densities, viscosities, cetane or octane numbers
• CPC Class Codes: F02D 2200/0612 determined by estimation
• CPC Class Codes: F02D 2200/1012 Engine speed gradient
• CPC Class Codes: F02D 41/0025 Controlling engines characterised by use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
• CPC Class Codes: F02D 41/047 Taking into account fuel evaporation or wall wetting; special correction after fuel cut-off F02D41/126
• CPC Class Codes: F02D 41/1497 : With detection of the mechanical response of the engine
• CPC Class Codes: Y02T 10/30 : Use of alternative fuels, e.g. biofuels
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles

Abstract

A fuel volatility recognition method during the post-cranking step of an internal combustion engine; the recognition method contemplates the steps of: starting the internal combustion engine; adjusting the enrichment of the mixture burnt in the cylinders of the internal combustion engine according to a previously determined historic fuel volatility value; detecting the time evolution of the angular speed of a crankshaft of the internal combustion engine during the post-cranking step; determining the noise contained in the angular speed of the crankshaft by filtering the angular speed itself by means of a high-pass filter; comparing the noise contained in the angular speed of the crankshaft against at least one predetermined threshold value; and recognizing the fuel volatility according to the result of the comparison between the noise contained in the angular speed of the crankshaft and the predetermined recognition threshold.

Claims

1. ) A fuel volatility recognition method during the post-cranking step of an internal combustion engine (1);

the method comprising the steps of;

starting the internal combustion engine (1);

adjusting the enrichment of the mixture burnt in the cylinders (2) of the internal combustion engine (1) according to a previously determined historic fuel volatility value;

detecting the time evolution of the angular speed (ω

) of a crankshaft (4) of the internal combustion engine (1) during the post-cranking step;

determining the noise (r) contained in the angular speed (ω

) of the crankshaft (4) by filtering the angular speed (ω

) itself by means of a high-pass filter;

comparing the noise (r) contained in the angular speed (ω

) of the crankshaft (4) against at least one predetermined threshold value (Tv); and

recognizing the fuel volatility according to the result of the comparison between the noise (r) contained in the angular speed (ω

) of the crankshaft (4) and the predetermined recognition threshold (Tv).

2. ) A recognition method according to claim 1, wherein, if the noise (r) contained in the angular speed (ω

) of the crankshaft (4) is lower than the predetermined recognition threshold value (Tv), then the real fuel volatility value is not lower than the previously determined historic fuel volatility value.

3. ) A recognition method according to claim 1, wherein if the noise (r) contained in the angular speed (ω

) of the crankshaft (4) is higher than the predetermined recognition threshold value (Tv) then the real fuel volatility value is lower than the previously determined historic fuel volatility value.

4. ) A recognition method according to claim 3, wherein the difference between the real fuel volatility value and the previously determined historic fuel volatility value depends on the difference between the noise (r) contained in the angular speed (ω

) of the crankshaft (4) and the previously determined recognition threshold value (Tv).

5. ) A recognition method according to claim 1, wherein the step of detecting the time evolution of the angular speed (ω

) of the crankshaft (4) of the internal combustion engine (1) during the post-cranking step contemplates the further steps of;

detecting the combustion time (tc) employed by the crankshaft (4) to cover the angular measurement ranges within which the combustion of each cylinder (2) of the internal combustion engine (1) occurs; and

generating a time-sorted combustion time vector.

6. ) A recognition method according to claim 5, wherein each angular measurement range presents a width of approximately 108°

-120°

.

7. ) A recognition method according to claim 1 and comprising the further step of filtering the noise (r) contained in the angular speed (ω

) of the crankshaft (4) by means of a low-pass filter before comparing against the previously determined threshold value (Tv).

8. ) A recognition method according to claim 1 and comprising the further step of using the real fuel volatility value recognized according to the result of the comparison between the noise (r) contained in the angular speed (ω

) of the crankshaft (4) and the predetermined recognition threshold (Tv) for adjusting the enrichment of the mixture burnt in the cylinders (2).

9. ) A recognition method according to claim 8, wherein the mixture burnt in the cylinders (2) is enriched if the noise (r) contained in the angular speed (ω

) of the crankshaft (4) is higher than the predetermined recognition threshold value (Tv).

10. ) A control method of an internal combustion engine (1) during the post-cranking step;

the control method comprises the steps of;

starting the internal combustion engine (1);

adjusting the enrichment of the mixture burnt in the cylinders (2) of the internal combustion engine (1) according to a previously determined historic fuel volatility value;

detecting the time evolution of the angular speed (ω

) of a crankshaft (4) of the internal combustion engine (1) during the post-cranking step;

determining the noise (r) contained in the angular speed (ω

) of the crankshaft (4) by filtering the angular speed (ω

) itself by means of a high-pass filter;

comparing the noise (r) contained in the angular speed (ω

) of the crankshaft (4) against at least one predetermined threshold value (Tv); and

varying the enrichment of the mixture burnt in the cylinders (2) according to the result of the comparison between the noise (r) contained in the angular speed (ω

) of the crankshaft (4) and the predetermined recognition threshold (Tv).

11. ) A recognition method according to claim 10, wherein the mixture burnt in the cylinders (2) is enriched if the noise (r) contained in the angular speed (ω

) of the crankshaft (4) is higher than the predetermined recognition threshold value (Tv).

12. ) A recognition method according to claim 10, wherein the enrichment of the mixture burnt in the cylinders (2) is decreased if the noise (r) contained in the angular speed (ω

) of the crankshaft (4) is lower than the predetermined recognition threshold value (Tv).

13. ) A recognition method according to claim 12, and comprising the further steps of:

comparing the noise (r) contained in the angular speed (ω

) of the crankshaft (4) against at least one predetermined threshold value (Tv) again after having decreased the enrichment of the mixture; and

maintaining the decrease in enrichment of the mixture only if the noise (r) contained in the angular speed (ω

) of the crankshaft (4) is still lower than the predetermined recognition threshold value Tv.

14. ) A recognition method according to claim 13, wherein a recursive algorithm which progressively decreases the mixture enrichment is used until the noise (r) contained in the angular speed (ω

) no longer exceed the predetermined recognition threshold (Tv) and at this point increases the enrichment of the mixture and stops.

15. ) A recognition method according to claim 10, wherein the step of detecting the time evolution of the angular speed (ω

) of the crankshaft (14) of the internal combustion engine (1) during the post-cranking step contemplates the further steps of;

detecting the combustion time (tc) employed by the crankshaft (4) to cover the angular measurement ranges within which the combustion of each cylinder (2) of the internal combustion engine (1) occurs; and

generating a time-sorted combustion time vector.

16. ) A recognition method according to claim 15, wherein each angular measurement range presents a width of approximately 108°

-120°

.

17. ) A recognition method according to claim 10 and comprising the further step of filtering the noise (r) contained in the angular speed (ω

) of the crankshaft (4) by means of a low-pass filter before comparing against the previously determined threshold value (Tv).