In-chassis determination of fuel injector performance

• US 20030200957A1
• Filed: 04/26/2002
• Published: 10/30/2003
• Est. Priority Date: 04/26/2002
• Status: Active Grant

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Shinogle, Ronald D.
• Granted Patent: US 6,748,928 B2
• Time in Patent Office: Days
• US Class Current: 123/480
• CPC Class Codes: F02D 2041/0012 with selective deactivation of cylinders
• CPC Class Codes: F02D 2041/2055 with means for determining actual opening or closing time
• CPC Class Codes: F02D 2041/389 for injecting directly into the cylinder
• CPC Class Codes: F02D 41/20 Output circuits, e.g. for controlling currents in command coils
• CPC Class Codes: F02D 41/365 with means for controlling timing and distribution
• CPC Class Codes: F02D 41/401 Controlling injection timing F02D41/402 takes precedence
• CPC Class Codes: F02M 65/002 Measuring fuel delivery of multi-cylinder injection pumps
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

It is known that the performance of actual fuel injectors tends to deviate from performance of nominal fuel injectors in both quantity and timing of each fuel injection event. These deviations in timing and/or quantity can be a function of such variables as the on-time itself, rail pressure in the case of hydraulically actuated fuel injectors, and engine temperature. In addition, these variations in performance can change over the life of the fuel injector. Therefore, in order to accurately correct for performance deviations in each individual fuel injector, the invention can include an up-to-date diagnostic of that deviation in performance. The present invention includes in-chassis strategies for evaluating fuel injector performance deviations in both quantity and timing, and further includes software strategies for applying control signal adjustments to make all of the fuel injectors in a given engine behave more uniformly and more like a nominal fuel injector.

Claims

1. An in-chassis fuel injector diagnostic system comprising:

an engine mounted on a chassis;

a plurality of electronically controlled fuel injectors attached to said engine;

at least one electromotive sensor operably coupled to at least one of said electronically controlled fuel injectors; and

an electronic control module in communication with said electronically controlled fuel injectors and said at least one electromotive sensor, and including a fuel injector quantity deviation algorithm, and including a fuel injector timing deviation algorithm.

2. The system of claim 1 including at least one electronically controlled compression release brake attached to said engine.

3. The system of claim 1 wherein each of said fuel injectors includes at least one electromagnetic valve connected to an electronic circuit;

and

said electromotive sensor includes a monitor coupled to said electronic circuit.

4. The system of claim 3 wherein said at least one electromagnetic valve includes an electrical actuator operably coupled to a needle control valve.

5. The system of claim 3 wherein said at least one electromagnetic valve includes an electrical actuator operably coupled to an actuation fluid control valve.

6. The system of claim 3 including at least one electrically controlled compression release brake attached to said engine.

7. The system of claim 6 wherein said at least one electromagnetic valve includes an electrical actuator operably coupled to at least one of a needle control valve and an actuation fluid control valve.

8. The system of claim 2 wherein said fuel injector quantity deviation algorithm includes a testing operation mode for simultaneously operating a first portion of engine cylinders in a power mode and a second portion in a braking mode.

9. The system of claim 1 wherein said fuel injector timing deviation algorithm includes a signal to injection delay deviation determinator.

10. The system of claim 9 wherein said fuel injector quantity deviation algorithm includes a testing operation mode for simultaneously operating a first portion of engine cylinders in a power mode and a second portion in a braking mode.

11. The system of claim 1 wherein said fuel injector quantity deviation algorithm includes a speed change test mode in which less than all engine cylinders are operated in a power mode over an engine speed change.

12. The system of claim 11 wherein said fuel injector timing deviation algorithm includes a signal to injection delay deviation determinator.

13. The system of claim 1 wherein said electronic control module includes a control signal adjustment algorithm operably coupled to said fuel injector quantity deviation algorithm and said fuel injector timing deviation algorithm.

14. A method of determining a fuel injector performance deviation from nominal, comprising the steps of:

estimating a fuel injection quantity deviation at least in part by operating an engine with less than all cylinders in a power mode, and determining at least one of an injector response and an engine response; and

estimating a fuel injection timing deviation at least in part by coupling an electromotive sensor with an electronically controlled valve of a fuel injector, and energizing the electronically controlled valve.

15. The method of claim 14 wherein said step of estimating a fuel injection quantity deviation includes a step of operating a portion of engine cylinders in a braking mode during said step of operating an engine.

16. The method of claim 14 wherein said step of estimating a fuel injection quantity deviation includes changing engine speed during said operating step.

17. The method of claim 14 wherein said step of estimating a fuel injection timing deviation includes monitoring for pulses in an electronic circuit associated with said electronically controlled valve.

18. The method of claim 17 wherein said step of estimating a fuel injection quantity deviation includes at least one of:

operating a portion of engine cylinders in a braking mode while operating a different portion in a power mode; and

changing engine speed while operating less than all engine cylinders in a power mode.

19. An in-chassis method of trimming fuel injector operation in an engine, comprising the steps of:

performing timing deviation in-chassis diagnostic testing;

storing timing deviation data in memory;

performing quantity deviation in-chassis diagnostic testing;

storing timing deviation data in memory; and

adjusting a control signal to a fuel injector based at least in part on said quantity deviation data and said timing deviation data.

20. The method of claim 19 including a step of coupling at least one electromotive sensor with each fuel injector;

and

said step of performing quantity deviation in-chassis diagnostic testing includes a step of operating less than all engine cylinders in a power mode.