Fuel identifier algorithm

• US 6,283,102 B1
• Filed: 11/04/1999
• Issued: 09/04/2001
• Est. Priority Date: 11/04/1999
• Status: Expired due to Term

• Current Assignee: FCA US LLC (Stellantis NV)
• Original Assignee: Daimler Chrysler Corporation (Mercedes-Benz Group AG)
• Inventors: Nelson, Brian J., Wielenga, Jason E., Alicke, Luiz R., Adams, Joseph B.
• Primary Examiner(s): SOLIS, ERICK R
• Application Number:
  US09/433,895
• Time in Patent Office: 670 Days
• Field of Search: 73/350.2, 123/1.A, 123/575, 123/435, 123/436
• US Class Current: 123/575
• CPC Class Codes: F02D 19/088 by estimation, i.e. without using direct measurements of a corresponding sensor
• 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 41/1497 With detection of the mechanical response of the engine
• CPC Class Codes: Y02T 10/30 Use of alternative fuels, e.g. biofuels

Abstract

A method for identifying high driveability index fuel for use in a motor vehicle engine includes the steps of determining an engine rotational speed after the engine has started, measuring an elapsed time required for the engine rotational speed to increase from a predetermined low limit to a predetermined high limit, and identifying high driveability index fuel when the elapsed time is greater than a predetermined time limit.

Claims

1. A method for identifying high driveability index fuel for use in a motor vehicle engine, the method comprising the steps of:

determining an engine rotational speed;

beginning to measure an elapsed time once said engine rotational speed reaches a predetermined low limit

ceasing to measure said elasped time once said engine rotational speed reaches a predetermined high limit wherein said predetermined low limit and said predetermined high limit define a window capturing the lowest rate of said engine rotational speed; and

identifying high driveability index fuel when said elapsed time is greater than a predetermined time limit.

2. The method of claim 1 wherein said step of determining an engine rotational speed includes measuring said engine rotational speed for a period of time after the engine is started.

3. The method of claim 1 wherein said predetermined time limit is greater than the time required for an engine burning non-high driveability index fuel to pass from said predetermined low limit to said predetermined high limit.

4. The method of claim 1 wherein said predetermined time limit ranges from about 0.08 to 0.26 seconds.

5. The method of claim 1 wherein said predetermined low limit and said predetermined high limit define a window capturing the lowest rate of increase of said engine rotational speed.

6. A method for controlling an engine of a motor vehicle comprising the steps of:

determining an engine rotational speed;

measuring a rate of increase of said engine rotational speed from a predetermined low limit to a predetermined high limit; and

determining if a high driveability index fuel is present by comparing said rate of increase to a predetermined rate; and

modifying an engine control parameter to account for the presence of said high driveability index fuel by revising a roughness goal to compensate for the lesser volatility of said high driveability index fuel.

7. The method of claim 6 wherein said step of modifying an engine control parameter includes revising a roughness goal to compensate for the lesser volatility of said high driveability index fuel.

8. The method of claim 6 wherein said step of modifying an engine control parameter includes modifying a rate of change in which said roughness goal is reached.

9. The method of claim 6 wherein the step of modifying an engine control parameter includes implementing a less aggressive correction factor when said engine rotational speed is greater than a target speed.

10. The method of claim 6 wherein said low limit and said high limit are less than 2000 revolutions per minute.

11. The method of claim 10 wherein said low limit is about 200 revolutions per minute.

12. The method of claim 10 wherein said high limit is about 750 revolutions per minute.

13. A method for controlling an engine of a motor vehicle comprising the steps of:

determining an engine rotational speed;

measuring a rate of increase of said engine rotational speed from a predetermined low limit to a predetermined high limit;

determining if a high driveability index fuel is present by comparing said rate of increase to a predetermined rate;

determining when a throttle is open; and

modifying an engine control parameter to account for the presence of said high driveability index fuel if said throttle is open when the engine is started.

14. A method for controlling an engine of a motor vehicle comprising the steps of:

determining an engine rotational speed;

measuring a rate of increase of said engine rotational speed from a predetermined low limit to a predetermined high limit;

determining if a high driveability index fuel is present by comparing said rate of increase to a predetermined rate;

determining when the engine was last run; and

modifying an engine control parameter to account for the presence of said high driveability index fuel if the engine was run in less than a predefined time period.

15. An engine control system for a motor vehicle comprising:

a control module and

a fuel identifier module for determining the presence of a high driveability index fuel, said fuel identifier module in communication with said control module, said control module notifying said engine control system if said high driveability index fuel is present comprising a counter to determine a length of time for an engine rotational speed to pass from a low limit to a high limit and wherein said length of time ranges from about 0.08 seconds to 0.26 seconds.

16. The engine control system for a motor vehicle of claim 15 wherein said fuel identifier module includes a counter to determine a length of time for an engine rotational speed to pass from a low limit to a high limit.

17. The engine control system for a motor vehicle of claim 16 wherein said length of time ranges from about 0.08 seconds to 0.26 seconds.

18. The engine control system for a motor vehicle of claim 15 further including an initialization module for switching said fuel identifier module from an inoperable mode to an operable mode.

19. The engine control system for a motor vehicle of claim 18 wherein said initialization module includes a fuel level sensor, said fuel level sensor signaling said initialization module to switch said fuel identifier module into said operable mode when fuel has been added.

20. An engine control system for a motor vehicle comprising:

a control module;

a fuel identifier module for determining the presence of a high driveability index fuel, said fuel identifier module in communication with said control module, said control module notifying said engine control system if said high driveability index fuel is present; and

an initialization module includes a history register to record the presence of said high driveability index fuel over time, said initialization module sending a signal indicating the presence of high driveability index fuel if the history register contains a certain frequency of records.