System and method for predicting quantity of injected fuel and adaptation to engine control system

• US 6,725,147 B2
• Filed: 10/31/2001
• Issued: 04/20/2004
• Est. Priority Date: 10/31/2001
• Status: Expired due to Fees

• Current Assignee: International Engine Intellectual Property Company, LLC (Volkswagen AG)
• Original Assignee: International Engine Intellectual Property Company, LLC (Volkswagen AG)
• Inventors: Mollin, Chad
• Primary Examiner(s): Wolfe, Willis R.
• Assistant Examiner(s): Hoang, Johnny H.
• Application Number:
  US10/003,980
• Publication Number:
  US 20030083801A1
• Time in Patent Office: 902 Days
• Field of Search: 701/101-105, 123/446, 123/478, 123/480
• US Class Current: 701/104
• CPC Class Codes: F02D 2041/1433 using a model or simulation of the system
• CPC Class Codes: F02D 2041/2058 using information of the actual current value
• CPC Class Codes: F02D 41/064 at cold start F02D41/067 takes precedence
• CPC Class Codes: F02D 41/1408 Dithering techniques
• CPC Class Codes: F02D 41/2416 Interpolation techniques
• CPC Class Codes: F02D 41/2467 for injectors
• CPC Class Codes: F02D 41/2477 characterised by the method used for learning
• CPC Class Codes: F02D 41/34 with means for controlling injection timing or duration
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

A method of deriving a formula (FIG. 4) for calculating a quantity of fuel injected by an electric-actuated fuel injector (16) during an injection wherein duration of the injection is set by duration of an electric signal (P1, P2) applied to the fuel injector and pressure (ICP) at which the fuel is injected is set by pressure of hydraulic fluid applied to the fuel injector. The fuel injector is mapped by applying, various combinations of different selected hydraulic fluid pressures and different selected durations of the electric signal to create data sets of the corresponding selected hydraulic fluid pressure, the corresponding selected electric signal duration, and the quantity of fuel injected. Data from the data sets is processed to create terms of a multiple term mathematical formula that is used to calculate the quantity of fuel injected.

Claims

1. A method of deriving a formula for calculating a quantity of fuel injected by an electric-actuated fuel injector during an injection wherein duration of the injection is set by duration of an electric signal applied to the fuel injector and pressure at which the fuel is injected is set by pressure of hydraulic fluid applied to the fuel injector, the method comprising:

mapping the fuel injector by applying, to the fuel injector, various combinations of different selected hydraulic fluid pressures and different selected durations of the electric signal, and for each combination, measuring the quantity of fuel injected to create a corresponding data set for the combination that comprises the corresponding selected hydraulic fluid pressure, the corresponding selected electric signal duration, and the quantity of fuel injected in consequence of the application, to the fuel injector, of the corresponding selected hydraulic fluid pressure and the corresponding selected electric signal duration; and

processing data from the data sets to create terms of a multiple term mathematical formula that is used to calculate the quantity of fuel injected, wherein the terms of the formula include as variables, the electric signal duration and the hydraulic fluid pressure.

2. A method as set forth in claim 1 wherein the processing step comprises an intermediate step that comprises:

for each selected hydraulic fluid pressure, processing from the data sets that include that selected hydraulic fluid pressure, the electric signal durations and the quantities of fuel injected to create data for coefficients for terms of a respective intermediate formula for calculating the quantity of fuel injected at the selected hydraulic pressure as a function of the electric signal duration.

3. A method as set forth in claim 2 wherein the intermediate processing step comprises:

for each selected hydraulic fluid pressure, creating the data for the coefficients for the terms of the respective intermediate formula by processing, by linear regression, the electric signal durations and the quantities of fuel injected from the data sets that include that selected hydraulic fluid pressure.

4. A method as set forth in claim 3 wherein the processing step includes a further intermediate step of processing the data for the coefficients for the terms of the intermediate formulas to create certain data that appears in coefficients for respective terms of the formula for calculating the quantity of fuel injected, the latter terms including as variables, electric signal duration and hydraulic fluid pressure.

5. A method as set forth in claim 4 wherein the further intermediate step comprises creating the certain data that appears in the coefficients for terms of the formula for calculating the quantity of fuel injected by processing the data for the coefficients for terms of the intermediate formulas according to best fit processing.

6. A method as set forth in claim 5 including a still further intermediate step that comprises processing, by non-linear regression, data appearing in the coefficients for terms of the formula for calculating the quantity of fuel injected to refine those coefficients for improved formula accuracy.

7. A method as set forth in claim 1 wherein the processing step comprises processing the electric signal durations and the quantities of fuel injected according to a process that yields certain data, one portion of which appears in a coefficient for a term of the formula that contains the electric signal duration as a first-power variable and another portion of which appears in a coefficient for a term of the formula that contains the hydraulic fluid pressure as a one-half-power variable.

8. A method as set forth in claim 1 wherein each duration of the electric signal is cooperatively defined by one variable that initiates actuation of the fuel injector to initiate an injection and another variable that terminates actuation of the fuel injector to terminate the injection, and the processing step comprises an intermediate step that comprises:

for each selected hydraulic fluid pressure, processing, by linear regression, from the data sets that include that selected hydraulic fluid pressure, the values of the variables that define the electric signal duration and the quantities of fuel injected to create data for coefficients for terms of a respective intermediate formula for calculating the quantity of fuel injected at the selected hydraulic pressure as a function of the one and the another variables.

9. A method as set forth in claim 8 wherein the processing step includes the further intermediate step of processing the data for the coefficients for terms of the intermediate formulas to create certain data that appears in coefficients for first, second, and third terms of the formula for calculating the quantity of fuel injected, wherein the first term includes the one variable that initiates an injection, the second term includes the another variable that terminates an injection, and the third term includes hydraulic fluid pressure as a variable.

10. A method as set forth in claim 9 wherein the further intermediate step comprises creating the certain data that appears in the coefficients for the first, second, and third terms by processing the data for the coefficients for the terms of the intermediate formulas according to best fit processing.

11. A system for deriving a formula for calculating a quantity of fuel injected by an electric-actuated fuel injector during an injection wherein duration of the injection is set by duration of an electric signal applied to the fuel injector and pressure at which the fuel is injected is set by pressure of hydraulic fluid applied to the fuel injector, the system comprising:

mapping apparatus for mapping the fuel injector by applying, to the fuel injector, various combinations of different selected hydraulic fluid pressures and different selected durations of the electric signal, and for each combination, measuring the quantity of fuel injected to create a corresponding data set for the combination that comprises the corresponding selected hydraulic fluid pressure, the corresponding selected electric signal duration, and the quantity of fuel injected in consequence of the application, to the fuel injector, of the corresponding selected hydraulic fluid pressure and the corresponding selected electric signal duration; and

processing apparatus for processing data from the data sets to create terms of a multiple term mathematical formula for calculating the quantity of fuel injected, wherein the terms of the formula include as variables, the electric signal duration and the hydraulic fluid pressure.

12. A system as set forth in claim 11 wherein the processing apparatus operates to perform an intermediate step that comprises:

for each selected hydraulic fluid pressure, processing from the data sets that include that selected hydraulic fluid pressure, the electric signal durations and the quantities of fuel injected to create data for coefficients for terms of a respective intermediate formula for calculating the quantity of fuel injected at the selected hydraulic pressure as a function of the electric signal duration.

13. A system as set forth in claim 12 wherein the processing apparatus operates to perform the intermediate processing step by creating, for each selected hydraulic fluid pressure, the data for the coefficients for the terms of the respective intermediate formula by processing, by linear regression, the electric signal durations and the quantities of fuel injected from the data sets that include that selected hydraulic fluid pressure.

14. A system as set forth in claim 13 wherein the processing apparatus operates to perform a further intermediate step of processing the data for the coefficients for the terms of the intermediate formulas to create certain data that appears in coefficients for respective terms of the formula for calculating the quantity of fuel injected, the latter terms including as variables, electric signal duration and hydraulic fluid pressure.

15. A system as set forth in claim 14 wherein the processing apparatus operates to perform the further intermediate step by creating the certain data that appears in the coefficients for terms of the formula for calculating the quantity of fuel injected by processing the data for the coefficients for terms of the intermediate formulas according to best fit processing.

16. A system as set forth in claim 15 wherein the processing apparatus operates to perform a still further intermediate step that comprises processing, by non-linear regression, data appearing in the coefficients for terms of the formula for calculating the quantity of fuel injected to refine those coefficients for improved formula accuracy.

17. A system as set forth in claim 11 wherein the processing apparatus operates to process the electric signal durations and the quantities of fuel injected according to a process that yields certain data, one portion of which appears in a coefficient for a term of the formula that contains the electric signal duration as a first-power variable and another portion of which appears in a coefficient for a term of the formula that contains the hydraulic fluid pressure as a one-half-power variable.

18. A system as set forth in claim 17 wherein each duration of the electric signal is cooperatively defined by one variable that initiates actuation of the fuel injector to initiate an injection and another variable that terminates actuation of the fuel injector to terminate the injection, and the processing apparatus operates to perform an intermediate step that comprises:

for each selected hydraulic fluid pressure, processing, by linear regression, from the data sets that include that selected hydraulic fluid pressure, the values of the variables that define the electric signal duration and the quantities of fuel injected to create data for coefficients for terms of a respective intermediate formula for calculating the quantity of fuel injected at the selected hydraulic pressure as a function of the one and the another variables.

19. A system as set forth in claim 18 wherein the processing apparatus operates to perform the further intermediate step of processing the data for the coefficients for terms of the intermediate formulas to create certain data that appears in coefficients for first, second, and third terms of the formula for calculating the quantity of fuel injected, wherein the first term includes the one variable that initiates an injection, the second term includes the another variable that terminates an injection, and the third term includes hydraulic fluid pressure as a variable.

20. A system as set forth in claim 19 wherein the processing apparatus operates to perform the further intermediate step by creating the certain data that appears in the coefficients for the first, second, and third terms by processing the data for the coefficients for the terms of the intermediate formulas according to best fit processing.

21. An internal combustion engine comprising:

one or more electric-actuated fuel injectors each of which injects fuel into a respective combustion chamber of the engine as a function of injector control pressure and the duration of an electric actuating signal that sets the duration of a fuel injection to achieve an injection quantity determined at least in part by a desired fueling data representing desired fueling of the engine;

and an engine control system comprising one or more processors that calculate the desired fueling data, and from the desired fueling data, the duration of the electric actuating signal for each fuel injector by processing the desired fueling data and data representing injector control pressure, including processing, according to a mathematical formula, data correlated with the desired fueling data and data representing injector control pressure, to develop data that the control system further processes to calculate the duration of the electric actuating signal.

22. An engine as set forth in claim 21 wherein each duration of the electric actuating signal is cooperatively defined by one variable that initiates actuation of a fuel injector to initiate an injection and another variable that terminates actuation of that fuel injector to terminate that injection, and wherein the control system selects data for the one variable based on the desired fueling data, processes the selected data for the one variable and the injector control pressure data according to the formula to develop data for the another variable that terminates the injection, and wherein the one variable one sets the time at which the electric actuating signal begins and the another variable sets the time at which the electric actuating signal terminates.

23. An engine as set forth in claim 22 wherein the control system selects a predetermined constant as data for the one variable when the desired fueling data exceeds a predefined limit, but equates the one variable to the another variable when the desired fueling data is equal to or less than the predefined limit.

24. An engine as set forth in claim 22 wherein each fuel injector comprises plural electric actuators, one of which is energized to begin a fuel injection and another of which is energized to terminate the fuel injection, and wherein the one variable sets the time at which the one actuator is energized and the another variable sets the time at which the another actuator is energized.

25. An engine as set forth in claim 22 wherein the control system comprises an engine controller comprising a processor that calculates the desired fueling data and an injector control module that comprises a processor that processes the desired fueling data calculated by the engine controller and the data representing the injector control pressure to develop data defining the duration of the electric actuating signal.