Method and system for detection of fuel quality using engine power output and NOx emission values

• US 10,466,225 B2
• Filed: 04/25/2014
• Issued: 11/05/2019
• Est. Priority Date: 04/30/2013
• Status: Active Grant

• Current Assignee: Scania CV AB (Volkswagen AG)
• Original Assignee: Scania CV AB (Volkswagen AG)
• Inventors: Nordin, Mikael
• Primary Examiner(s): Fan, Michele
• Application Number:
  US14/787,058
• Publication Number:
  US 20160069855A1
• Time in Patent Office: 2,020 Days
• CPC Class Codes: F01N 13/008 Mounting or arrangement of exhaust sensors in or on exhaust apparatus sensor arrangements for engine control F02D41/1439
• CPC Class Codes: F02D 19/06 peculiar to engines working with pluralities of fuels, e.g. alternatively with light and heavy fuel oil, other than engines indifferent to the fuel consumed
• CPC Class Codes: F02D 2200/0612 determined by estimation
• 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 41/1461 of the exhaust gases emitted by the engine
• CPC Class Codes: F02D 41/1462 with determination means using an estimation
• CPC Class Codes: F02D 41/1497 With detection of the mechanical response of the engine
• CPC Class Codes: G01N 33/22 Fuels; Explosives
• CPC Class Codes: G01N 33/2829 Mixtures of fuels
• CPC Class Codes: Y02T 10/30 Use of alternative fuels, e.g. biofuels

Abstract

A method and a system for detecting a fuel quality in a vehicle including a first determination unit to determine a correction factor k_kW for fuel as a quotient between an output fo_kW required to propel a vehicle and a reference output eng_kW which an engine in the vehicle is estimated to yield;

$k_{kW}=\frac{{\mathrm{fo}}_{kW}}{{\mathrm{eng}}_{kW}};$
a second determination unit to determine a correction factor k_NOx for exhaust gas emissions as a quotient between a value measured in the vehicle for nitrogen oxides eng_NOx and a reference value for nitrogen oxides ECU_NOx;

$k_{\mathrm{NOx}}=\frac{{\mathrm{eng}}_{\mathrm{NOx}}}{{\mathrm{ECU}}_{\mathrm{NOx}}};$
and a detection unit to detect the fuel quality based on a relation between the correction factor k_kW for fuel and the correction factor k_NOx for exhaust gas emissions.

Claims

1. A method of operating a vehicle having a system with a parameter that can be optimized based on fuel quality, comprising:

determining a correction factor k_kW for fuel as a quotient between an output fo_kW required to propel said vehicle and a reference output eng_kW which an engine in said vehicle is estimated to yield;

2. A method according to claim 1, further comprising determining said output fo_kW required to propel said vehicle based on a driving resistance F_drivingres acting on said vehicle and on a vehicular speed v of said vehicle.

3. A method according to claim 2, wherein said driving resistance F_drivingres comprises external forces to be overcome for said vehicle to maintain a constant speed or to accelerate.

4. A method according to claim 3, further comprising calculating said driving resistance F_drivingres based on at least a weight m for said vehicle, a rolling friction force F_roll acting on said vehicle and an air resistance force F_air acting on said vehicle.

5. A method according to claim 1, wherein said reference output eng_kW is related to an engine output P_eng calculated to be yielded by an engine in said vehicle.

6. A method according to claim 5, wherein said engine output P_eng is determined based on a speed co for said engine and on efficiency of a quantity of a selected fuel for said fuel.

7. A method according to claim 1, further comprising said reference output eng_kW based on a quantity M_fuel of fuel consumed, an energy content E_fuel in said fuel and an efficiency n_eng for said engine.

8. A method according to claim 7, further comprising determining said measured value for nitrogen oxides eng_NOx based on a standardized mass flow Φ

_{NOx_mass_norm} of nitrogen oxides through said exhaust gas treatment system and a gas flow Φ

_gas through said engine in said vehicle.

9. A method according to claim 1, further comprising determining an estimated value for nitrogen oxides eng_NOx based on a measurement by at least one nitrogen oxide-sensitive sensor placed near an exhaust gas treatment system in said vehicle.

10. A method according to claim 1, wherein said reference value for nitrogen oxides ECU_NOx represents a predetermined value for a predetermined fuel.

11. A method according to claim 10, wherein said predetermined fuel is comprised of diesel.

12. A method according to claim 1, further comprising said detecting of said fuel quality is based on a quality correction factor k_quality, and calculating said quality correction factor as a quotient between said correction factor k_kW for fuel and said correction factor k_NOx for exhaust gas emissions;

13. A method according to claim 12, further comprising determining said detecting of said fuel quality by comparing a value for said quality correction factor k_quality with at least a predetermined interval corresponding to a known fuel quality.

14. A method according to claim 12, wherein, if a predetermined fuel, to which said reference value for nitrogen oxides ECU_NOx and said reference output eng_kW relate, is comprised of diesel, said correction factor k_quality has a value equal to one of the group:

k_quality≈

1, which is equivalent to k_kW≈

1 and k_NOx≈

1, when said fuel contains 100% diesel;

k_quailty≈

1.7, which is equivalent to k_kW≈

0.7 and k_NOx≈

0.4, when said fuel contains 100% ethanol;

k_quailty≈

0.7, which is equivalent to k_kW≈

0.9 and k_NOx≈

1.3, when said fuel contains 100% FAME (Fatty Acid Methyl Ester); and

k_quality≈

0.8, which is equivalent to k_kW≈

0.98 and k_NOx≈

1.16, when said fuel contains 50% FAME.

15. A method according to claim 14, wherein said detecting of fuel quality is deemed reliable if said changes to said correction factor k_kW for fuel and to said correction factor k_NOx for exhaust gas emissions are uniform.

16. A method according to claim 14, wherein said detecting of fuel quality is deemed unreliable if said changes to said correction factor k_kW for fuel and to said correction factor k_NOx for exhaust gas emissions are not uniform.

17. A method according to claim 1, further comprising performing a reliability check on said detection of fuel quality by analyzing a change to said correction factor k_kW for fuel and a change to said correction factor k_NOx for exhaust gas emissions.

18. A method according to claim 1, further comprising said detection of fuel quality is performed after a refilling of said fuel in said vehicle.

19. A method according to claim 18, wherein said refilling of said fuel is deemed to have taken place when a fuel level in a fuel tank in said vehicle has increased at least 20% since a previous level measurement.

20. A method according to claim 1, further comprising detecting said fuel quality under essentially stationary conditions of said vehicle.

21. A method according to claim 20, wherein said essentially stationary conditions are equivalent to an engine in said vehicle having had a speed w within an interval equal to ±

10 r.p.m., and a load L within an interval equal to ±

50 Nm during a time interval T₁-T₂ min.

22. A method according to claim 20, wherein said essentially stationary conditions are equivalent to normal main road and/or motorway driving having taken place during a predetermined time interval T₁-T₂ min.

23. A computer software product including a non-transitory computer-readable medium and a computer program stored on said readable medium;

said computer program comprising program code configured such that when said program code is executed in a computer, said code causes said computer to execute the method in accordance with claim 1.