Electronic control of engine fuel delivery

• US 5,091,858 A
• Filed: 10/26/1989
• Issued: 02/25/1992
• Est. Priority Date: 01/09/1989
• Status: Expired due to Term

• Current Assignee: Prestolite Wire LLC (General Cable Corporation)
• Original Assignee: Digital Fuel Injection, Inc.
• Inventors: Paielli, Perry M.
• Primary Examiner(s): Lall, Parshotham S.
• Assistant Examiner(s): TRANS, VINCENT N
• Application Number:
  US07/429,789
• Time in Patent Office: 852 Days
• Field of Search: 364/431.1-431.04, 364/900, 364/200, 123/480, 365/228, 365/230.01
• US Class Current: 701/115
• CPC Class Codes: F02D 41/2422 Selective use of one or more tables
• CPC Class Codes: F02D 41/249 Methods for preventing the loss of data

Abstract

An engine fuel delivery control system includes an engine having at least one fuel injector fuel injector responsive to electronic control signals for delivering fuel to the engine cylinders and a plurality of sensor for supplying electrical sensor signals as various functions of engine operating conditions. An electronic engine control unit includes an electronic memory storing engine control parameters in a variety of look-up tables, a microprocessor-based controller for periodically addressing the memory tables and obtaining required control parameters as a function of sensor signal inputs, and circuitry for supplying control signals to the injectors as a predetermined function of the control parameters obtained from the look-up tables. Apparatus for selectively varying the control parameters in the look-up tables includes facility for up-loading selected tables from the engine control unit memory, monitoring engine operation as reflected by addressing of the parameter tables in real time, and selectively initiating a programming mode of operation. In such programming mode of operation, addressing of the control tables is inhibited in the electronic control unit, and the control parameters obtained from the tables immediately prior to onset of the programming mode of operation are employed to supply control signals to the injectors during the programming mode of operation. In this way, engine operation continues uninterrupted during the programming mode of operation.

Claims

1. An engine control system that comprises:

an engine including at least one mechanism responsive to electronic control signals for affecting engine operation and at least one sensor for supplying electrical sensor signals as a function of engine operating conditions,

an electronic control unit including an electronic memory storing engine control parameters in at least one lookup table, means for periodically addressing said memory and obtaining said control parameters as a function of said sensor signals, and means for supplying said control signals to said mechanism as a predetermined function of said control parameters, and

means for selectively varying said control parameters in said table including means for initiating a memory-programming mode of operation, means for inhibiting said periodically-addressing means during said memory-programming mode of operation, and means for employing control parameters obtained from said table prior to said memory-programming mode of operation to supply said control signals during said mode of operation such that engine operation continues during said memory-programming mode of operation.

2. The system set forth in claim 1 wherein said selectively-varying means comprises means for reading said table from said electronic memory, means for displaying said table to an operator, means responsive to an operator for identifying specific parameters in said table, means for selectively varying said specific parameters in said table, and means responsive to the operator for downloading said specific parameter varied by the operator into said table stored in said electronic memory.

3. The system set forth in claim 2 wherein said table-displaying means includes means coupled to said electronic control unit and responsive to said sensor signals for displaying current operating conditions at the engine.

4. The system set forth in claim 3 wherein said displaying means comprises a screen for displaying said table in alphanumeric tabular format as a function of engine operating conditions, wherein said identifying means comprises means forming a cursor on said screen and means for selectively moving said cursor on said screen so as to overlie parameter entries in said table on said screen, and wherein said selectively-varying means comprises means for selectively varying the parameter entry that said cursor overlies.

5. The system set forth in claim 4 wherein said selectively varying means comprises an alphanumeric keyboard.

6. The system set forth in claim 3 wherein said displaying means comprises a screen for displaying said table in graphic format as a function of engine operating conditions, wherein said identifying means comprises means forming a cursor on said screen and means for selectively moving said cursor on said screen along said graphic format display, and wherein said selectively-varying means comprises means for selectively varying the parameter entry at the intersection of said cursor and said graphic display.

7. The system set forth in claim 1 for controlling delivery of fuel to the engine wherein said mechanism comprises at least one electronic fuel injector, wherein said at least one sensor includes a first sensor for providing a signal as a function of engine speed and a second sensor for providing a signal as a function of engine air manifold pressure, and wherein said at least one look-up table comprises a first table containing a plurality of injector pulse width control parameters addressable as a function of engine speed and air manifold pressure.

8. The system set forth in claim 7 wherein said at least one sensor further includes a third sensor for providing a signal as a function of engine operating temperature, and wherein said at least one look-up table comprises a second table of parameters addressable as a function of engine temperature for modifying parameters read from said first table.

9. An electronic control system for an internal combustion engine that includes:

an engine having at least one mechanism responsive to electronic control signals for affecting operation of the engine and at least one sensor for supplying electrical sensor signals in real time as a function of operating conditions at the engine,

an electronic control unit including memory means having prestored wherein at least one look-up table of engine control parameters addressable as a function of engine condition signals, microprocessor-based control means including means for receiving said sensor signals, means for addressing said memory to obtain control parameters from said table as a function of said sensor signals, and means for generating said control signals to said mechanism as a preselected function of said control parameters, and

means for selectively reprogramming said table comprising means for selectively reading and temporarily storing said table, means for displaying said table to an operator, means on said displaying means responsive to an operator for selectively identifying specific parameter entries in said table to be varied, means for varying said specific entries on said displaying means and in said temporarily-storing means, and means for downloading parameter entries varied by the operator into said memory table,

said control means including means for employing said look-up table in said memory means to continue operation of the engine during reprogramming of said table.

10. The system set forth in claim 9 wherein said displaying means comprises a screen for displaying said table in alphanumeric tabular format as a function of engine operating conditions, wherein said identifying means comprises means forming a cursor on said screen and means for selectively moving said cursor on said screen so as to overlie parameter entries in said table on wherein said screen, and said selectively-varying means comprises means for selectively varying the parameter entry that said cursor overlies.

11. The system set forth in claim 10 wherein said selectively varying means comprises an alphanumeric keyboard.

12. The system set forth in claim 9 wherein said displaying means comprises a screen for displaying said table in graphic format as a function of engine operating conditions, wherein said identifying means comprises means forming a cursor on said screen and means for selectively moving said cursor on said screen along said graphic format display, and wherein said selectively-varying means comprises means for selectively varying the parameter entry at the intersection of said cursor and said graphic display.

13. The system set forth in claim 9 wherein said table-displaying means includes means for displaying current operating conditions at the engine.

14. In a method of controlling operation of an engine that comprises the steps of:

(a) storing an electronic table of engine control parameters as addressable functions of engine operating conditions,

(b) monitoring operating conditions at the engine,

(c) periodically addressing said table as a function of said conditions to obtain at least one control parameter associated with current operating conditions at the engine, and

(d) controlling at least one mechanism associated with the engine affecting operation at the engine as a function of said at least one control parameter associated with said current operating conditions,

the improvement for selectively varying parameters in said table without interrupting operation at the engine comprising the steps of;

(e) detecting a mode of operation in which parameters in said table are to be varied,

(f) upon onset of said mode of operation, storing the at least one control parameter obtained in said step (c) and thereafter inhibiting said step (c) during duration of said mode of operation, and

(g) employing in said step (d) said parameter stored in said step (f) during said mode of operation.

15. The method set forth in claim 14 comprising the additional steps during said mode of operation of:

(h) displaying said table in its entirety to an operator,

(i) variably indicating display table locations at which parameters may be varied,

(j) varying parameters at said display table locations indicated in said step (i) under control of the operator,

(k) loading parameters varied in said step (j) into said electronic table at associated table locations, and then

(l) terminating said mode of operation.

16. An electronic system for controlling fuel delivery to an internal combustion engine having at least one electronic fuel injector and a plurality of sensors for providing electronic sensor signals that vary as functions of operating conditions at the engine, said system comprising:

an electronic memory having a multiplicity of injector pulse width control parameters prestored therein as a look-up table addressable as a function of said sensor signals,

means for selectively varying said parameters in said table comprising means for displaying the entire said table to an operator, means on the display responsive to an operator for selectively identifying a table location at which the associated parameter is to be varied, means for selectively varying said associated parameter to a modified parameter on said display, and means responsive to the operator for replacing said associated parameter at said table location with said modified parameter, and

an electronic controller including means for receiving said sensor signals, means for addressing said table as a function of said sensor signals to obtain a first pulse width control parameter associated with current operating conditions at the engine, means responsive to said selectively-varying means and to said parameter replacing means to store said first parameter and inhibit addressing of said table while said table parameters are being varied, and means for energizing said injector for a time duration that varies as a function of said first parameter.

17. The system set forth in claim 16 wherein said table-displaying means includes means responsive to said sensors for displaying current operating conditions at the engine.

18. The system set forth in claim 17 wherein said table comprises a three-dimensional first table of parameters by engine speed and engine air manifold pressure.

19. The system set forth in claim 18 wherein said sensors include an oxygen sensor responsive to engine exhaust, wherein said means for displaying current operating conditions including means responsive to said oxygen sensor for displaying current air/fuel ratio information, and wherein said table-displaying means comprises a screen and means for displaying said first table and said air/fuel ratio information in separate display windows on said screen.

20. The system set forth in claim 19 wherein said table further comprises a two-dimensional second table of parameters by engine operating temperature, and wherein said table-displaying means comprises means for selecting between said first and second tables for display and modification at said screen.

21. The system set forth in claim 20 wherein said table-displaying means comprises means for displaying said second table in graphic format, wherein said identifying means comprises means forming a cursor on said screen and means for selectively moving said cursor on said screen along said graphic format display, and wherein said selectively-varying means comprises means for selectively varying the parameter entry at the intersection of said cursor and said graphic display.

22. The system set forth in claim 20 wherein said table-displaying means comprises means for displaying said first table in alphanumeric tabular format as a function of engine speed and air manifold pressure, wherein said identifying means comprises means forming a cursor on said screen and means for selectively moving said cursor on said screen so as to overlie parameter entries in said table on said screen, and wherein said selectively-varying means comprises means for selectively varying the parameter entry that said cursor overlies.

23. The system set forth in claim 22 wherein said selectively varying means comprises an alphanumeric keyboard.