Method and structure for controlling an apparatus, such as a fuel injector, using electronic trimming

Abstract

A structure and method for electronically minimizing or eliminating performance variation of an apparatus controllable by a control signal, such as an electronically-controlled fuel injector, is disclosed. The method includes the steps of measuring the resultant characteristics of the apparatus at a plurality of operating conditions, such as timing and delivery characteristics of the fuel injector, adjusting the control signal as a function of the measured resultant characteristics, such as by adjusting a base timing and duration or pulse width of a fuel delivery command signal for a fuel injector, and controlling the apparatus in accordance with the adjusted control signal to reduce performance variation. A structure is disclosed to compensate or trim for individual injector variation, includes an electronic control module having a memory for storing trim signals for each injector, the trim signals being derived from observed performance parameter values taken at a plurality of operating conditions, a plurality of sensors for detecting at least one, and preferably a plurality of operating parameters and generating a respective one, and preferably a plurality of, operating parameter signals, and a means for communicating the trim signals to the memory. The electronic control module adjusts a base fuel delivery signal for each injector as a function of the trim data signals for each injector.

We claim:  
     
       1. A method of operating an apparatus of the type having a nominal resultant characteristic at a plurality of operating conditions when controlled in accordance with a control signal, comprising the steps of: 
       measuring a resultant characteristic associated with the apparatus at a plurality of operating conditions;  
       adjusting the control signal as a function of the variation between the measured resultant characteristics and the nominal resultant characteristic and as a function of the operating condition of said apparatus; and  
       controlling the apparatus in accordance with the adjusted signal such that the resultant characteristics of the apparatus when operated approach the nominal resultant characteristics.  
     
     
       2. The method of  claim 1 , further comprising the step of: 
       associating the resultant characteristics measured in said measuring step with the apparatus.  
     
     
       3. The method of  claim 2 , wherein the control signal is generated by a control means having a memory means, and wherein said associating step includes the substep of storing data indicative of the measured resultant characteristics of the apparatus in the memory means. 
     
     
       4. The method of  claim 2  wherein said associating step includes the substep of permanently recording data indicative of the measured resultant characteristics of the apparatus on said apparatus. 
     
     
       5. The method of  claim 4 , wherein the control signal is generated by a control means, and wherein said associating step includes the substeps of reading the data recorded on the apparatus and inputting the read data into the control means. 
     
     
       6. The method of  claim 1  wherein said adjusting step includes the substeps of categorizing the apparatus, based on the measured resultant characteristics, into one of a plurality of trim categories wherein each category has an associated offset value, and modifying the controls signal as a function of the offset value. 
     
     
       7. The method of  claim 6  wherein said modifying step is further performed as a function of an actual operating condition. 
     
     
       8. The method of  claim 1  wherein said adjusting step includes the substeps of determining the relationship between the nominal resultant characteristics as a function of the control signal and the measured resultant characteristics of the apparatus as a function of the control signal, and modifying the control signal based upon the determined relationship. 
     
     
       9. The method of  claim 8  wherein said modifying step is further performed as a function of an actual operating condition. 
     
     
       10. A method of operating a plurality of electronically-controlled fuel injectors of the type having a nominal start of injection characteristic wherein fuel injection is controlled by a fuel delivery signal, comprising the steps of: 
       measuring, for each injector, a respective start of injection characteristic;  
       associating, for each injector, the measured start of injection characteristic with the respective injector;  
       adjusting, for each injector, the fuel delivery signal as a function of the variation of the respectively associated measured start of injection characteristic from the nominal start of injection characteristic;  
       controlling each injector in accordance with the respective adjusted fuel delivery signal to reduce start of injection variation.  
     
     
       11. The method of  claim 10 , wherein the fuel delivery signal is generated by a control means having a memory means, and wherein said associating step includes the substep of storing data indicative of the measured start of injection characteristic of each injector in the memory means. 
     
     
       12. The method of  claim 10 , wherein said associating step includes the substep of permanently recording data indicative of the measured start of injection characteristic of each injector on a respective injector. 
     
     
       13. The method of  claim 12 , wherein said associating step includes the substep of categorizing each injector, based on a respective measured start of injection characteristic, into one of a plurality of trim categories wherein the permanently recorded data is a trim category designation. 
     
     
       14. The method of  claim 12 , wherein the fuel delivery signal is generated by a control means, and wherein said associating step includes the substeps of reading the data recorded on the injector and inputting the read data into the control means. 
     
     
       15. The method of  claim 14 , wherein said permanently recording data substep is performed by bar coding the respective data indicative of the measured start of injection on each injector to generate a respective bar code, and wherein said reading and inputting substeps are performed by scanning the bar codes recorded on the injectors, interpreting each bar code to reconstruct the data indicative of the measured start of injection characteristic, and transmitting the reconstructed data into the control means. 
     
     
       16. The method of  claim 14  wherein said permanently recording data substep is performed by affixing, for each injector, a resistor having a resistance value indicative of the measured start of injection of the respective injector, and wherein said reading and inputting sub-steps are performed by sensing, for each injector, the resistance value of the respectively affixed resistor, and interpreting, for each injector, the sensed resistance value to reconstruct the data indicative of the measured start of injection characteristic. 
     
     
       17. The method of  claim 13  wherein each category has an associated offset value, and wherein said adjusting step includes the substep of modifying the fuel delivery signal for each injector as a function of a respective offset value. 
     
     
       18. A method of operating a plurality of electronically-controlled fuel injectors wherein fuel injection is controlled by a fuel delivery signal, the injectors being of the type having a nominal delivery characteristic as a function of operating conditions, comprising the steps of: 
       measuring, for each injector, a respective delivery characteristic at a plurality of operating conditions;  
       associating, for each injector, the measured delivery characteristic with the respective injector;  
       adjusting for each injector, the fuel delivery signal as a function of the variation of the respectively associated measured delivery characteristic from the nominal delivery characteristic at each operating condition of the injector;  
       controlling each injector in accordance with the respective adjusted fuel delivery signal to minimize injector to injector delivery variation.  
     
     
       19. The method of  claim 18 , wherein said associating step includes the substep of permanently recording data indicative of the measured delivery characteristic of each injector on a respective injector. 
     
     
       20. The method of  claim 19 , wherein the fuel delivery signal is generated by a control means and wherein said associating step includes the substeps of reading the data recorded on the injector and inputting the read data into the control means. 
     
     
       21. The method of  claim 20  wherein said permanently recording data substep is performed by bar coding the respective data indicative of the measured delivery on each injector to generate a respective bar code, and wherein said reading and inputting substeps are performed by scanning the bar codes recorded on the injectors, interpreting each bar code to reconstruct the data indicative of the measured delivery characteristic, and transmitting the reconstructed data into the control means. 
     
     
       22. The method of  claim 20  wherein said permanently recording data substep is performed by affixing to each injector a resistor having a resistance value indicative of the measured delivery characteristic of the respective injector, and wherein said reading and inputting substeps are performed by sensing, for each injector, the resistance value of the respective affixed resistor and interpreting, for each injector, the sensed resistance value to reconstruct the data indicative of the measured delivery characteristic. 
     
     
       23. The method of  claim 18 , wherein the fuel delivery signal is generated by a control means having a memory means, and wherein said associating step includes the substep step of storing data indicative of the measured delivery characteristic of each injector in the memory means. 
     
     
       24. The method of  claim 19  wherein said associating step includes the substep of categorizing each injector, based on a respective measured delivery characteristic, into one of a plurality of trim categories wherein the permanently recorded data is a trim category designation. 
     
     
       25. The method of  claim 24  wherein each category has an associated offset value, and wherein said adjusting step includes the substep of modifying the fuel delivery signal for each injector as a function of a respective offset value. 
     
     
       26. A method of operating a plurality of electronically-controlled fuel injectors wherein fuel injection is controlled by a fuel delivery signal generated by a control means having a memory means, the injectors being of the type having a nominal start of injection characteristic and nominal delivery characteristic, comprising the steps of: 
       measuring, for each injector, a respective start of injection characteristic and delivery characteristic;  
       categorizing each injector into one of a plurality of trim categories as a function of the variation of the measured start of injection and delivery characteristics from the respective nominal start of injection and delivery characteristics, each trim category having an associated start of injection and delivery offset value;  
       recording the category into which each injector was categorized in said categorizing step on a respective injector;  
       storing the respective category recorded on each injector in the memory means;  
       calculating the fuel delivery signal as a function of actual operating conditions based on nominal start of injection and delivery characteristics;  
       adjusting the fuel delivery signal for each injector as a function of the respective start of injection and delivery offset values;  
       controlling each injector in accordance with the respective adjusted fuel delivery signal to reduce start of injection and delivery variation.  
     
     
       27. The method of  claim 26  wherein the injectors are hydraulically-actuated injectors which are further controlled by an actuating fluid pressure command signal, the method further comprising the step of adjusting the actuating fluid pressure command signal for each injector as a function of the respective start of injection and delivery offset values. 
     
     
       28. The method of  claim 26  wherein said measuring step is performed at a plurality of operating conditions, and wherein said adjusting step includes the substep of further adjusting the fuel delivery command signal as a function of an actual operating condition. 
     
     
       29. The method of  claim 26  wherein said recording step includes the substep of affixing, for each injector, a respective bar code that is indicative of the category into which the respective injector was categorized. 
     
     
       30. The method of  claim 26  wherein said recording step includes the substep of affixing, for each injector, a respective resistor having a resistance value that is indicative of the category into which the respective injector was categorized. 
     
     
       31. A system for controlling the delivery of fuel through a plurality of fuel injectors to an engine, each injector being of the type characterized by at least one observed performance parameter, comprising: 
       sensor means for detecting a plurality of operating parameters and generating a respective plurality of operating parameter signals indicative of the parameter detected;  
       control means responsive to said operating parameter signals for generating a base fuel delivery signal for each injector; each fuel injector being coupled with said control means to receive a respective base fuel delivery signal for controlled fuel delivery to the engine;  
       memory means coupled with said control means for storing trim signals for each injector, said trim signals being derived from observed performance parameter values taken at a plurality of operating conditions;  
       means for communicating said trim signals to said memory means;  
       said control means being responsive to said trim signals for trimming said base fuel delivery signal for each injector as a function of said trim signals and as a function of said operating parameter signals for reducing performance parameter variation.  
     
     
       32. A method of preparing for shipment an apparatus of a type having measurable resultant characteristics at a plurality of operating conditions when controlled in accordance with a control signal, comprising the steps of: 
       
         measuring at least one resultant characteristic associated with the apparatus at a plurality of operating conditions;  
       
       
         determining a control signal adjustment as a function of a variation between the measured resultant characteristics and nominal resultant characteristics and as a function of an operating condition of the apparatus; and  
       
       
         recording data indicative of the control signal adjustment on the apparatus. 
       
     
     
       33. The method of  claim 32  wherein the apparatus is a fuel injector; and 
       
         the plurality of operating conditions include different engine operating conditions. 
       
     
     
       34. The method of  claim 33  wherein the control signal adjustment includes a fuel injection quantity adjustment that is a function of an operating condition of the fuel injector. 
     
     
       35. The method of  claim 34  wherein said recording step includes a step of attaching a bar code to the fuel injector. 
     
     
       36. The method of  claim 35  wherein the control signal adjustment includes a fuel injection timing adjustment. 
     
     
       37. The method of  claim 36  wherein said attaching step includes a step of locating the bar code at a location that is readable after the fuel injector is installed in an engine. 
     
     
       38. A method of operating an apparatus of a type having measurable resultant characteristics at a plurality of operating conditions when controlled in accordance with a control signal, comprising the steps of: 
       
         reading data recorded on the apparatus that is indicative of a control signal adjustment;  
       
       
         inputting the control system adjustment data into an electronic control module;  
       
       
         establishing a control communication link between the apparatus and the electronic control module; and  
       
       
         controlling the apparatus in accordance with an adjusted control signal that is a function of a nominal control signal, an operating condition and the control signal adjustment data. 
       
     
     
       39. The method of  claim 38  wherein the apparatus is a fuel injector; and the method includes a step of: 
       
         installing the fuel injector in an engine. 
       
     
     
       40. The method of  claim 39  wherein said reading step includes a step of scanning a bar code attached to the fuel injector. 
     
     
       41. The method of  claim 40  wherein the control signal adjustment data includes fuel injection quantity adjustment data that is a function of an operating condition of the fuel injector. 
     
     
       42. The method of  claim 41  wherein the control signal adjustment data includes fuel injection timing adjustment data. 
     
     
       43. An actuatable mechanism that produces a measurable resultant characteristic in response to an electronic control signal, comprising: 
       
         a body;  
       
       
         an electrical actuator attached to said body;  
       
       
         a data recording attached to said body and including control signal adjustment data that is a function of a variation between measured resultant characteristics and nominal resultant characteristics and as a function of an operating condition of the mechanism. 
       
     
     
       44. The mechanism of  claim 43  wherein the mechanism is a fuel injector. 
     
     
       45. The mechanism of  claim 44  wherein said data recording includes a bar code. 
     
     
       46. The mechanism of  claim 45  wherein the control signal adjustment data includes fuel injection quantity adjustment data that is a function of an operating condition of the fuel injector. 
     
     
       47. The method of  claim 46  wherein the control signal adjustment data includes a fuel injection timing adjustment data.